TECHNOLOGICAL FIELD

The technological field of the present invention, in some embodiments thereof, relates to adherence of a device to surfaces and objects, and, more particularly, but not exclusively, to an adherent device with non-damaging release.

BACKGROUND

Many mechanisms are known to cause two objects to resist separation from each other.

Adhesive materials, such as glue and cement, create a strong bond between the two objects. Typically, the bond is permanent and may be severed only by applying a strong force between the objects.

Hook-and-loop fasteners include two components which are attached to the opposing surfaces to be fastened. Pressing the two together causes the hooks to catch in the loops and the two pieces fasten or bind temporarily. The two components may be separated by pulling them apart so that the hooks release from the loops.

Some ways to create a bond between objects utilize heat. Welding heats the objects to their liquid states, so that they fuse together and unite when they cool. Soldering joins two or more objects together by melting solder into the joint. When the solder cools it holds the objects together.

SUMMARY

A device for controllably adhering to and detaching from a surface (denoted here the “adherent device”) creates an adhesive force between itself and a surface by freezing a liquid absorbed in the portion of the device abutting the surface (for example in a layer of sponge). A thermal control element is thermally coupled to the absorbent material. The thermal control element is capable of cooling (and optionally heating) the absorbent material, and thus the liquid absorbed within it. The liquid freezes into a solid when the thermal control element cools the absorbent material to a temperature below the liquid’s liquid to solid transition temperature. While the liquid is frozen, the absorbent material adheres to the surface. When the frozen liquid thaws, the absorbent material releases from the surface. Any liquid left on the surface may evaporate. No adhesive or other material remains permanently on the surface.

Technical effects of embodiments of the invention described herein may include one or more of: a) The device may be used multiple times, to adhere to and detach from the same or different surfaces simply by adjusting the temperature of the absorbent material. Detaching from the surface does not render the device inoperable or require the replacement of parts for further operation. b) Simple control of adherence and detaching by bringing the absorbent material to a required temperature. A simple temperature sensor may be used to determine whether the absorbent material is at a suitable temperature for adhering or detaching. c) Adaptable to different operating conditions by selecting materials and temperature mechanisms suited for the required operating conditions. d) Does not require adhesives or other permanent bonding technique.

According to a first aspect of some embodiments of the present invention there is provided a device for controllably adhering to and detaching from a surface. The device includes an absorbent material and a thermal control element thermally coupled to the absorbent material. The absorbent material is capable of absorbing a liquid that adheres to a surface when positioned in physical contact with the surface and the liquid freezes and to detach from the surface when the frozen liquid thaws. The thermal control element cools the absorbent material to a temperature below a liquid to solid transition temperature of the liquid.

According to a second aspect of some embodiments of the present invention there is provided a device for controllably adhering to and detaching from a surface. The device includes an absorbent material and a thermal control element thermally coupled to the absorbent material. The absorbent material is capable of absorbing a non-crystalline material adheres to and detaches from a surface positioned in physical contact with the surface based on the viscosity of the non-crystalline material. The thermal control element control the viscosity of the non-crystalline material by adjusting the temperature of the non-crystalline material. According to some embodiments of the first aspect of the invention, the device further includes control circuitry that control the adhering and detaching by adjusting a temperature of the thermal control element.

According to some embodiments of the first aspect of the invention, the thermal control element includes at least one thermoelectric cooler (TEC), wherein the temperature of the absorbed liquid is established by controlling a level and direction of current flow through the at least one TEC.

According to some embodiments of the first aspect of the invention, the thermal control element includes a refrigeration compression system.

According to some embodiments of the first aspect of the invention, the thermal control element includes: a heat exchanger that dissipates heat from the liquid absorbed in the absorbent material to a first fluid at a temperature lower than the liquid to solid transition temperature; a reservoir that contains the first fluid; and a circulator that circulates the first fluid between the heat exchanger and the reservoir.

According to some embodiments of the first aspect of the invention, the thermal control element thaws the first liquid by heating the absorbent material.

According to some embodiments of the first aspect of the invention, the absorbent material flexibly conforms to a shape of the surface.

According to some embodiments of the first aspect of the invention, the device further includes a receptacle for holding the liquid and a pump for supplying the liquid to the absorbent material.

According to some embodiments of the first aspect of the invention, the device further includes a heat sink that dissipates heat from the thermal control element.

According to some embodiments of the first aspect of the invention, heat is dissipated from the thermal control element by at least one of: circulating a coolant through at least one channel running through the heat sink; blowing air on fins of the heat sink; and expanding a refrigerant in an evaporator within the heat sink. According to some embodiments of the first aspect of the invention, heat is dissipated from the thermal control element by applying a second fluid to the exterior of the temperature control element.

According to some embodiments of the first aspect of the invention, the device is configured to adhere to a bottom of a surface.

According to a second aspect of some embodiments of the present invention there is provided method for controllably adhering to and detaching from a surface. Adhering to the surface includes cooling an absorbent material in physical contact with a surface and having a liquid absorbed therewithin to a temperature below a liquid to solid transition temperature of the liquid. Detaching from the surface includes bringing the temperature of the absorbent material to a temperature above the solid to liquid transition temperature of the liquid.

According to some embodiments of the second aspect of the invention, adhering to the surface further includes positioning the absorbent material in physical contact with the surface.

According to some embodiments of the second aspect of the invention, bringing the temperature of the absorbent material to above the solid to liquid transition temperature includes terminating the cooling of the absorbent material.

According to some embodiments of the second aspect of the invention, bringing the temperature of the absorbent material to above the solid to liquid transition temperature includes heating the absorbent material.

According to some embodiments of the second aspect of the invention, cooling the absorbent material is performed by at least one thermoelectric cooler (TEC) thermally coupled to the absorbent material, and the cooling the absorbent material includes controlling a level and direction of current flow through the TEC.

According to some embodiments of the second aspect of the invention, cooling the absorbent material is performed by a refrigeration compression system thermally coupled to the absorbent material.

According to some embodiments of the second aspect of the invention, cooling the absorbent material includes circulating a first fluid at a temperature lower than the liquid to solid transition temperature through a heat exchanger thermally coupled to the absorbent material.

According to some embodiments of the second aspect of the invention, the method further includes supplying the liquid to the absorbent material.

According to some embodiments of the second aspect of the invention, the method further includes dissipating heat generated during the cooling.

According to some embodiments of the second aspect of the invention, dissipating the heat generated during the cooling includes at least one of: circulating a coolant through at least one channel running through a heat sink; blowing air on fins of a heat sink using a fan; expanding a refrigerant in an evaporator within a heat sink; and applying a second fluid to an exterior of a thermal control element. According to some embodiments of the second aspect of the invention, the method further includes pressing the absorbent material onto the surface such that the absorbent material conforms to a shape of the surface.

According to a third aspect of some embodiments of the present invention there is provided a system for moving upon a surface. The system includes multiple adherent devices, a motor assembly and control circuitry. Each of the adherent devices includes an absorbent material and a thermal control element thermally coupled to the absorbent material. The absorbent material is configured to absorb a liquid and to be positioned in physical contact with a surface, wherein the absorbent material adheres to the surface when the liquid freezes and detaches from the surface when the frozen liquid thaws. The thermal control element cools the absorbent material to a temperature below a liquid to solid transition temperature of the liquid. The motor assembly is configured to move the adherent devices upon the surface. The control circuitry is configured to control the motor assembly and respective temperatures of the thermal control elements. The control circuitry is further configured to move the system upon the surface by: detaching at least one of the adherent devices from the surface while retaining remaining ones of the adherent devices adhered to the surface; repositioning the at least one detached adherent device at respective next locations on the surface using the motor assembly; and re-adhering the at least one repositioned adherent device to the surface.

According to some embodiments of the third aspect of the invention, detaching an adherent device from the surface includes thawing a liquid frozen within the respective absorbent material by adjusting the temperature of the respective thermal control element.

According to some embodiments of the third aspect of the invention, re-adhering an adherent device to the surface includes freezing a liquid absorbed within the respective absorbent material by adjusting the temperature of the respective thermal control element.

According to some embodiments of the third aspect of the invention, at least one of the thermal control elements includes at least one thermoelectric cooler (TEC), wherein a temperature of the absorbed liquid is established by controlling a level and direction of current flow through the at least one TEC.

According to some embodiments of the third aspect of the invention, at least one of the thermal control elements includes a refrigeration compression system.

According to some embodiments of the third aspect of the invention, at least one of the thermal control elements includes: a heat exchanger configured to dissipate heat from the liquid absorbed in the absorbent material to a first fluid at a temperature lower than the liquid to solid transition temperature; a reservoir configured to contain the first fluid; and a circulator configured to circulate the first fluid between the heat exchanger and the reservoir.

According to some embodiments of the third aspect of the invention, the thermal control elements are thermally coupled to respective heat sinks, and heat is dissipated from at least one of the thermal control elements by at least one of: circulating a coolant through at least one channel running through the thermal control element’s heat sink; blowing air on fins of the thermal control element’s heat sink; and expanding a refrigerant in an evaporator within the thermal control element’s heat sink. According to some embodiments of the third aspect of the invention, heat generated during the cooling is dissipated by applying a second fluid to an exterior of a thermal control element.

According to some embodiments of the third aspect of the invention, the absorbent material is configured to flexibly conform to a shape of the surface.

According to some embodiments of the third aspect of the invention, the system further includes at least one receptacle for holding the liquid and at least one pump for supplying the liquid to the absorbent materials.

According to some embodiments of the third aspect of the invention, the system is configured to move upon the bottom of a surface.

According to some embodiments of the third aspect of the invention, the adherent devices are attached to a belt.

According to some embodiments of the third aspect of the invention, the adherent devices are attached to respective robotic arms.

According to a fourth aspect of some embodiments of the present invention there is provided a device for controllably adhering to and detaching from a surface. The device includes an absorbent material and a thermal control element thermally coupled to the absorbent material. The absorbent material is capable of absorbing a non-crystalline material adheres to and detaches from a surface positioned in physical contact with the surface based on the viscosity of the non-crystalline material. The thermal control element control the viscosity of the non-crystalline material by adjusting the temperature of the non-crystalline material.

According to some embodiments of the fourth aspect of the invention, the device further includes control circuitry that control the adhering and detaching by adjusting a temperature of the thermal control element.

According to some embodiments of the fourth aspect of the invention, the thermal control element includes at least one thermoelectric cooler (TEC), wherein the temperature of the absorbed liquid is established by controlling a level and direction of current flow through the at least one TEC.

According to some embodiments of the fourth aspect of the invention, the thermal control element includes a refrigeration compression system. According to some embodiments of the fourth aspect of the invention, the thermal control element includes: a heat exchanger that dissipates heat from the liquid absorbed in the absorbent material to a first fluid at a temperature lower than the liquid to solid transition temperature; a reservoir that contains the first fluid; and a circulator that circulates the first fluid between the heat exchanger and the reservoir.

According to some embodiments of the fourth aspect of the invention, the thermal control element thaws the first liquid by heating the absorbent material.

According to some embodiments of the fourth aspect of the invention, the absorbent material flexibly conforms to a shape of the surface.

According to some embodiments of the fourth aspect of the invention, the device further includes a receptacle for holding the liquid and a pump for supplying the liquid to the absorbent material.

According to some embodiments of the fourth aspect of the invention, the device further includes a heat sink that dissipates heat from the thermal control element.

According to some embodiments of the fourth aspect of the invention, heat is dissipated from the thermal control element by at least one of: circulating a coolant through at least one channel running through the heat sink; blowing air on fins of the heat sink; and expanding a refrigerant in an evaporator within the heat sink.

According to some embodiments of the fourth aspect of the invention, heat is dissipated from the thermal control element by applying a second fluid to the exterior of the temperature control element.

According to some embodiments of the fourth aspect of the invention, the device is configured to adhere to a bottom of a surface.

Unless otherwise defined, all technical and/or scientific terms used within this document have meaning as commonly understood by one of ordinary skill in the art/s to which the present disclosure pertains. In case of conflict, the patent specification, including definitions, will control.

Methods and/or materials similar or equivalent to those described herein can be used in the practice and/or testing of embodiments of the present disclosure, and exemplary methods and/or materials are described below. Regarding exemplary embodiments described below, the materials, methods, and examples are illustrative and are not intended to be necessarily limiting.

Implementation of the method and/or system of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.

Some embodiments of the present disclosure are embodied as a system, method, or computer program product. For example, some embodiments of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro code, etc.) or an embodiment combining software and hardware aspects.

For example, hardware for performing selected tasks according to some embodiments of the present disclosure could be implemented as a chip or a circuit. As software, selected tasks according to some embodiments of the present disclosure could be implemented as a plurality of software instructions being executed by a computational device e.g., using any suitable operating system.

In some embodiments, one or more tasks according to some exemplary embodiments of method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage e.g., for storing instructions and/or data. Optionally, a network connection is provided as well. User interface/s e.g., display/s and/or user input device/s are optionally provided.

Some embodiments of the present disclosure may be described below with reference to flowchart illustrations and/or block diagrams. It will be understood that each step of the flowchart illustrations and/or block of the block diagrams, and/or combinations of steps in the flowchart illustrations and/or blocks in the block diagrams, may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart steps and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable medium that can direct a computer (e.g., in a memory, local and/or hosted at the cloud), other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium can be used to produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be run by one or more computational device to cause a series of operational steps to be performed e.g., on the computational device, other programmable apparatus and/or other devices to produce a computer implemented process such that the instructions which execute provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

FIG. 1A-1D are simplified block diagrams of a device for controllably adhering to and detaching from a surface, according to respective embodiments of the invention;

FIGS. 2A-2C are simplified diagrams of heat sinks, according to respective exemplary embodiments;

FIGS. 3-4 are simplified block diagrams of an adherent device, according to respective exemplary embodiments of the invention; FIGS. 5A-5E are simplified illustrations of adherent devices adhered to surfaces and objects having differing shapes and angles, according to embodiments of the invention;

FIGS. 6-7 are simplified flowcharts of a method for controllably adhering to and detaching from a surface, according to respective embodiments of the invention;

FIG. 8 is a simplified schematic diagram of a mobile system, according to an exemplary embodiment of the invention;

FIG. 9 is a simplified flowchart of a method for moving a mobile system upon a surface according to some embodiments of the invention;

FIG. 10 is a simplified illustration of an adherent device attached to a robotic arm, according to an exemplary embodiment of the invention; and

FIG. 11 is a simplified illustration of adherent devices mounted on a belt, according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure, in some embodiments, thereof, relates to a device, system and method for creating adherence to a surface by temperature control.

Reference is now made to FIGS. 1A-1D, which are simplified block diagrams of a device for controllably adhering to and detaching from a surface, according to respective embodiments of the invention.

Adherent device 100 includes absorbent material 110, thermal control element 120, and optionally heat sink 130. The adherent device may be attached to a surface at any angle. When adhered to a surface, the adherent device may be used to suspend or move another object or objects, as described in more detail below.

I. Absorbent Material

Absorbent material 110 is a material which is capable of absorbing a liquid. In order to adhere adherent device 100 to the surface, liquid is absorbed into absorbent material 110. Freezing the liquid creates an adhesive force between the absorbent material and a surface it is contact with. This causes adherent device 100 to adhere to the surface. When the frozen liquid thaws, the adhesive force weakens, and adherent device 100 detaches from the surface. Optionally, the liquid is water. In alternate embodiments, another liquid may be used, as described in more detail below.

As used herein the term “surface” means the substance to which the device or system will adhere. The surface may be flat or have a contoured or irregular shape. Optionally, the surface may have a gap in it (for example when it is formed from two or more adjacent objects).

As used herein the term “absorbent material” means any material that can absorb a liquid and be placed in contact with a surface.

As used herein the term “liquid to solid transition temperature” means the temperature at which a material changes phase from liquid to solid.

As used herein the term “solid to liquid transition temperature” means the temperature at which a material changes phase from solid to liquid.

As used herein the term “freezing” means bringing the liquid in the absorbent material to a temperature below its liquid to solid transition temperature, regardless of whether the solid is crystalline or amorphous.

As used herein the term “thawing” means bringing the liquid frozen in the absorbent material to a temperature above its solid to liquid transition temperature.

As used herein the term “liquid” means the substance absorbed by the absorbent material while in liquid phase.

As used herein the term “frozen liquid” means the substance absorbed by the absorbent material when it is changed into solid phase.

As illustrated in FIG. IB, absorbent material 110 is optionally flexible and conforms to the surface of the object 140 it is physical contact with. For example, absorbent material 110 may include a sponge and/or felt and/or cloth and/or a flexible solid that absorbs liquid within it.

Optionally, adherent device 100 is pressed onto the surface before the liquid is frozen. In an irregular surface, this increases the area of contact between absorbent material 110 and the surface, creating a stronger adhesion between them.

Optionally, absorbent material 110 is heated prior to placing it in contact with and/or pressing onto the surface, in order to ensure that the substance absorbed within it is in liquid phase. This enables adherent device 100 to operate in an environment that has an ambient temperature lower than or close to the liquid to solid transition temperature of the liquid.

II. Liquid

The liquid used in the device (i.e. absorbed into the absorbent material) is selected in accordance with the operational, environmental and other requirements for a specific device or for a system which includes adherent device(s). For example, the desired liquid to solid transition temperature may be affected by the ambient temperature in which the adherent device will be operating.

Liquids which may be used include but are not limited to: a) Water. b) Gallium (liquid to solid transition temperature of 29.8 °C). c) Rubidium (liquid to solid transition temperature of 39.3 °C) - Rubidium reacts with water to produce hydrogen and liquid RbOH. Optionally, when Rubidium is used the surface may be cleaned after the adherent device has been detached by applying water to the area. The reaction with water is exothermic. Further optionally, if the rubidium is in solid state the heat of the reaction may be used to melt it to prepare for the next attachment to a surface. d) Metals mixed to form liquid alloys - Examples of alloys that may be used for the adherent device include but are not limited to: a Gallium- Indium-Tin alloy (liquid to solid transition temperature of -19 °C), a Bismuth-Lead-Tin-Cadmium-Indium-Thallium alloy (liquid to solid transition temperature of 41.5 °C), or a Bismuth-Cadmium-Lead- Tin-Indium allow (liquid to solid transition temperature of 47 °C). As will be appreciated, alloys may be modified or developed to obtain a desired target liquid to solid transition temperature (for example, by increasing the content of gallium in the alloy). e) Octadecane (liquid to solid transition temperature of 29 °C). f) Hexadecane (liquid to solid transition temperature of 18.2 °C). g) Alcohols - Examples include but are not limited to: decanol (liquid to solid transition temperature of 6.4 °C), dodecanol (liquid to solid transition temperature of 24 °C) and tetradecanol (liquid to solid transition temperature of 38 °C). III. Thermal Control Element

Thermal control element 120 is thermally coupled to absorbent material 110. Thermal control element 120 controls the temperature of absorbent material 110 by cooling, and optionally heating, a thermally coupled absorbent material 110. When thermal control element 120 reduces the temperature of the liquid absorbed within absorbent material 110 beneath its liquid to solid transition temperature the liquid freezes. This causes adherent device 100 to adhere to the surface.

Optionally, the operation of thermal control element 120 is controlled by control signals input from an internal component of adherent device 100 (e.g. internal control circuitry) and/or from external device(s) or system(s). The control signals control, at least in part, the temperature of the portion of thermal control element 120 that is adjacent to absorbent material 110.

It is noted that the term "control signals” is not limited to digital signals. For example, when thermal control element 120 includes a thermoelectric cooler (TEC) the input signal may be a current supplied to the thermal control element 120.

In some embodiments of the invention, thermal control element 120 includes one or more one thermoelectric coolers (shown as TEC(s) 121 in FIG. 1A). A thermoelectric cooler (TEC) is a solid-state active heat pump which transfers heat from one side of the device to the other depending on the direction of the current. TEC(s) may be used for cooling absorbent material 110, and optionally for heating it. The temperature of the absorbed in liquid material 110 is established by controlling the level and direction of current flow through the TEC.

The number of TECs used depends on the implementation requirements. Using layered TECs increases the temperature range of thermal control element 120 relative to using a single TEC. However, efficiency decreases when the TECs operate over a greater temperature range.

Reference is now made to FIG. 1C, which is a simplified block diagram of an adherent device according to some embodiments of the invention. In FIG. 1C, thermal control element 120 includes a refrigeration compression system 122, which operates by compressing, condensing, and expanding a circulating refrigerant as known in the art. The temperature of the absorbent material is controlled by any means known in the art, for example, by controlling the rate of flow of the refrigerant through the compression system’s evaporator.

Reference is now made to FIG. ID, which is a simplified block diagram of an adherent device according to some embodiments of the invention. In FIG. ID, adherent device 100 does not include a heat sink. Instead, temperature control element 120 includes heat exchanger 123, reservoir 124 and circulator 125. Circulator 125 circulates a fluid from reservoir 124 through heat exchanger 123 and back to reservoir 124. The circulated fluid is at a temperature lower than the liquid to solid transition temperature, causing the liquid absorbed in absorbent material 110 to freeze.

In one example, the circulating fluid is liquid nitrogen, either in its liquid form or in its gas form. In a second example, the circulating fluid is ammonia.

As used herein the term “heat exchanger” means an element which has a cold fluid circulating through it and serves to cool the temperature control element to a temperature low enough to create adherence between the absorbent material and the surface.

In one embodiment, the amount of cold fluid stored in reservoir 124 is large enough to remain at cold enough for the entire period of operation of the device.

In another embodiment, the reservoir holds a cold solid which cools the fluid recirculated into the reservoir (e.g. a block of ice at -150 degrees C).

IV. Heat Dissipation from Thermal Control Element

In some embodiments, thermal energy dissipated from the liquid in the absorbent material may cause a temperature differential over thermal control element. In one example, the thermal control element includes a TEC and the temperature range across the thermal control element is approximately -10 °C on the cold side and 5 °C on the hot side.

Optionally, the adherent device includes a heat sink that is thermally coupled to the thermal control element. The heat sink dissipates heat from the thermal control element to ensure that it is capable of reducing the temperature of the liquid absorbed within the absorbent material to temperatures low enough to solidify the liquid. Reference is now made to FIGS. 2A-2C which are simplified diagrams of heat sinks, according to respective exemplary embodiments.

In FIG. 2A, a coolant is circulated through at least one channel 220 running through heat sink 210. The heat sink may include fins (not shown) which passively discharge heat to the surroundings.

In FIG. 2B, heat sink 230 has protruding fins 240. Fan 250 blows air onto fins 240 thereby dissipating heat from them.

In FIG. 2C, heat sink 260 is cooled by expanding a refrigerant in evaporator 270 within the heat sink. The refrigerant enters heat sink at high pressure and exits it at a lower pressure.

In cases where the thermal control element includes a refrigeration compression system (see FIG. 1C), the heat sink may be incorporated into the refrigeration compression system.

As used herein the term “coolant” means a substance that is used to reduce or regulate the temperature of the adherent device by flowing through a portion of the device.

As used herein the term “refrigerant” means a substance that dissipates heat by undergoing a phase change while flowing through a portion of the adherent device (e.g. an evaporator).

As used herein the term “heat sink” means an element that dissipates the heat generated by the adherent device away from the adherent device. The heat sink may have a coolant circulating through it and/or may include an evaporator where a refrigerant undergoes a phase change.

Alternately or additionally, heat is dissipated from the adherent device by applying a cold fluid onto an exterior of a thermal control element. Typically the temperature of the applied fluid is below the liquid to solid transition temperature of the liquid absorbed in the absorbent material. The cold fluid may be:

1) The liquid used to wet the absorbent material;

2) The coolant used to cool the heat sink;

3) The refrigerant used to cool the heat sink;

4) A different fluid. Reference is now made to FIG. 3, which is a simplified block diagram of an adherent device, according to an exemplary embodiment. Adherent device 300 includes absorbent material 310 and thermal control element 320, but does not include a heat sink. Thermal control element 320 is cooled by cold fluid 330, which is applied to the exterior of thermal control element 320. For example, the cold fluid may be stored in a tank above thermal control element 320 and flow or drip onto thermal control element when the tank is opened.

Optionally, heat dissipation by heat sink 130 is controlled by control signals input from an internal component of adherent device 100 (e.g. internal control circuitry) and/or from external device(s) or system(s). The control signals control, at least in part, the amount of heat dissipated from thermal control element 120, and thus the temperature of the portion of thermal control element 120 that is adjacent to absorbent material 110.

It is noted that the term "control signals” is not limited to digital signals. For example, when heat sink 120 is cooled by a coolant a control signal may be an analog signal to a valve that regulates the rate of flow through heat sink 120.

V. Adherent Device

Embodiments of the adherent device include any combination of the options described herein for absorbent material, liquid, thermal control element and heat dissipation.

For example, in one embodiment the absorbent material is sponge, the liquid is water, the thermal control element includes one or more TECs and heat dissipation is performed by running a coolant through the heat sink.

In a second embodiment, the absorbent material is sponge, the liquid is rubidium, the thermal control element is a refrigeration compression system and heat dissipation is performed by applying a fluid to the exterior thermal control element.

Many other embodiments are possible.

Reference is now made to FIG. 4, which is a simplified block diagram of an adherent device, according to some embodiments of the invention. Adherent device 400 includes absorbent material 410, thermal control element 420 and heat sink 430 described above. Adherent device 400 is arranged so that absorbent material 410 may be placed against a surface.

FIG. 4 shows an exemplary embodiment in which adherent device 400 includes a heat sink 430 for cooling thermal control element 420.

A fluid is stored in receptacle 470. The stored fluid (e.g. water) is used both to wet absorbent material 410 and to be circulated through heat sink 430 by pump 460.

As will be appreciated by the skilled person, other embodiments may be used, including but not limited to: a. Wetting absorbent material 410 by gravity (instead of a pump). Receptacle 470 would be placed higher than absorbent material 410; b. Using a different liquid for absorbent material 410 and fluid for heat sink 430. In this case they would be stored separately (e.g. receptacle 470 would be subdivided or in separate receptacles). c. Using a different method for dissipating heat from thermal control element 420 (e.g. phase change of a refrigerant in heat sink 430, cooling heat sink 430 with a fan and/or applying a fluid to thermal control element 420).

Optionally, adherent device 400 includes control circuitry 440 which controls the adherence and detaching to a surface or object. Specific control functions are dependent on the implementation of the adherent device. Examples of control functions performed by control circuitry 410 include but are not limited to: a. Controlling the rate of application of the liquid to absorbent material 410; b. Controlling the temperature of thermal control element 420. In an exemplary embodiment, thermal control element 420 includes at least one TEC and control circuitry 410 controls the direction and magnitude of the current flowing through the TEC(s). Alternately or additionally, thermal control element 120 includes a refrigeration compression system and control circuitry 410 controls the operation of the refrigeration compression system.

3) Controlling heat dissipation from thermal control element 420. In an exemplary embodiment, control circuitry 440 controls the operation of pump 460. In an alternate embodiment control circuitry 440 controls the flow of refrigerant through heat sink 430. In an additional or alternative embodiment, control circuitry 440 controls a fan (not shown) which cools fins on heat sink 430. In another additional or alternative embodiment, control circuitry 440 controls the application of a cooling fluid onto thermal control element 420.

Optionally, adherent device includes at least one temperature sensor 450 for monitoring the temperature of absorbent material 410 and providing a feedback signal to controller 440.

Optionally, adherent device includes power source 460 for providing power to active components. Alternately or additionally, adherent device 400 is powered by an external power source.

Reference is now made to FIGS. 5A-5E, which are simplified illustrations of adherent devices adhered to surfaces and objects having differing shapes and angles, according to embodiments of the invention. Adherent device 500 may be in accordance with any of the embodiments described herein.

In FIG. 5A illustrates an adherent device 500 adhered to a flat, vertical surface 510. Experimental results demonstrate that an adherent device which includes a 4 cm by 4 cm TEC, operating at a DC voltage of 5.8 Volts and 3.86 Amps is capable of securing an object weighing 6.8 kg. to a vertical surface (e.g. a wall). The adherent device’s heat sink is a 4 cm x 4 cm x 1 cm aluminum block through which a water mixture at 0 °C flows. A small pump (approximately 3 Watts, such as a typical aquarium pump) circulates water through the heat sink.

In FIG. 5B illustrates an adherent device 500 adhered to the bottom of a sloping surface 520. An object 530 is suspended from surface 520 using adherent device 500 and cable 535.

FIG. 5C illustrates an adherent device 500 adhered to the top of a sloping surface 540.

FIG. 5D illustrates an adherent device 500 attached to the top of object 560. Adherent device 500 is suspended from the bottom of a horizontal surface 550 by mechanical connectors 165 (e.g. cables or a clasp). Thus, adherent device 500 secures object 560 to horizontal surface 550. Experimental results demonstrate that an adherent device which includes a 4 cm by 4 cm TEC, operating at a DC voltage of 5.8 Volts and 3.86 Amps is capable of securing an object weighing 3 kg. to a horizontal surface (e.g. a ceiling). The adherent device’s heat sink is a 4 cm x 4 cm x 1 cm aluminum block through which a water mixture at 0 °C flows. A small pump (approximately 3 Watts, such as a typical aquarium pump) circulates water through the heat sink.

Reference is now made to FIG. 5E, which is a simplified illustration in which adherent device 500 is used to raise an object from a surface, according to an exemplary embodiment of the invention. Adherent device 500 is attached to the top of object 590 by freezing a liquid absorbed in the absorbent material as described herein Adherent device 500 is connected from above by cable 580 which runs over pulley 590. Object 570 is raised from the surface when a sideways force is applied to cable 580.

VI. Method for Adhering to and Detaching from a Surface

Reference is now made to FIG. 6, which is a simplified flowchart of a method for controllably adhering to and detaching from a surface according to some embodiments of the invention.

In 610 the absorbent material an absorbent material having a liquid absorbed within it is cooled to a temperature below a liquid to solid transition temperature of the liquid.

Optionally, cooling the absorbent material includes using at least one TEC thermally coupled to the absorbent material. Cooling the absorbent material includes controlling the level and direction of current flow through the TEC.

Optionally, cooling the absorbent material includes using a refrigeration compression system thermally coupled to the absorbent material.

Optionally, cooling the absorbent material includes circulating a fluid at a temperature lower than the liquid to solid transition temperature through heat exchanger thermally coupled to the absorbent material.

Optionally, in 620 the absorbent material is placed in physical contact with the surface.

Optionally, the method further includes pressing the absorbent material onto the surface such that the absorbent material conforms to a shape of the surface. Optionally, in 630 the absorbent material is detached from the surface by bringing the temperature of the absorbent material to above the solid to liquid transition temperature of the liquid.

Optionally the method further includes supplying the liquid to the absorbent material. In one example, the absorbent material is placed in physical contact with the surface and then the liquid is absorbed into it. In a second example, the liquid is first absorbed into absorbent material which is then placed in physical contact with the surface. Additional liquid may be supplied to the absorbent material over time and/or when the absorbent material is moved to a different location.

Optionally, the temperature of the absorbent material is brought above the solid to liquid transition temperature by terminating cooling of the absorbent material. The temperature of the absorbent material then rises to ambient temperature. Alternately or additionally, the temperature of the absorbent material is brought above the solid to liquid transition temperature by heating the absorbent material.

Optionally the method further includes dissipating heat generated during the cooling. Further optionally, dissipating heat generated during the cooling includes at least one of:

1. Circulating a coolant through at least one channel running through a heat sink;

2. Blowing air on fins of a heat sink using a fan;

3. Expanding a refrigerant in an evaporator within a heat sink; and

4. Applying a fluid to the exterior of a thermal control element.

Optionally, the method further includes collecting the liquid remaining on the surface after the adherent device is detached. Collecting the liquid reduces the rate of consumption of the liquid during repeated operation, so the device may operate longer with the same amount of liquid.

VII. Adherent Device with Non-crystalline Material

The embodiments described above are directed at a liquid which undergoes transitions from liquid to solid and from solid to liquid. Some materials are noncrystalline and do not undergo a discrete phase change. Instead the viscosity of the material increases as the temperature is lowered. In some embodiments of the invention, increasing and decreasing the viscosity of non-crystalline materials is used to control adherence to and detachment from a surface.

The structure of the adherent device for non-crystalline materials is substantially similar to the above described devices. It includes an absorbent material and thermal control element thermally coupled to the absorbent material. Optionally the device includes a heat sink.

The absorbent material absorbs a non-crystalline material.

Thermal control element controls the viscosity of the non-crystalline material by adjusting a temperature of the non-crystalline material. Cooling the non-crystalline material absorbed in the absorbent material to a low enough temperature reduces the viscosity and causes the absorbent material to adhere to a surface it is in physical contact with. When the temperature of the non-crystalline material rises to a high enough temperature, the viscosity of the non-crystalline material increases, and the absorbent material detaches from the surface.

Embodiments of the thermal control element are substantially similar to those described above for a liquid which undergoes phase transitions. Optionally, the thermal control element includes at least one of:

1. A TEC;

2. A refrigeration compression system; and

3. A heat exchanger cooled by a fluid circulated from a reservoir.

Embodiments of dissipating heat from the thermal control element are substantially similar to those described above for a liquid which undergoes phase transitions. Heat dissipation may be performed, for example, by one or more of:

1. Circulating a coolant through at least one channel running through a heat sink thermally coupled to the thermal control element;

2. Blowing air on fins of a heat sink thermally coupled to the thermal control element using a fan;

3. Expanding a refrigerant in an evaporator within a heat sink thermally coupled to the thermal control element; and

4. Applying a fluid to the exterior of a thermal control element. Reference is now made to FIG. 7, which is a simplified flowchart of a method for controllably adhering to and detaching from a surface according to embodiments of the invention. Adhering to the surface is performed in 710 by freezing a non-crystalline material absorbed into an absorbent material which is in contact with a surface.

In 710 the absorbent material an absorbent material having a non-crystalline material absorbed within it is cooled to a temperature at which the viscosity of the noncrystalline material is low enough to cause the absorbent material to adhere to the absorbent material.

Optionally, cooling the absorbent material includes using at least one TEC thermally coupled to the absorbent material. Cooling the absorbent material includes controlling the level and direction of current flow through the TEC.

Optionally, cooling the absorbent material includes using a refrigeration compression system thermally coupled to the absorbent material.

Optionally, cooling the absorbent material includes circulating a fluid at a temperature lower than the temperature required to obtain the required viscosity for adherence through a heat exchanger thermally coupled to the absorbent material.

Optionally, in 720 the absorbent material is placed in physical contact with the surface.

Optionally the method further includes pressing the absorbent material onto the surface such that the absorbent material conforms to a shape of the surface.

Optionally, in 730 the absorbent material is detached from the surface by bringing the temperature of the absorbent material to above the temperature required to obtain the required viscosity for detaching the absorbent material from the surface.

Optionally the method further includes supplying the liquid that solidifies without forming a crystalline state to the absorbent material. In one example, the liquid that solidifies without forming a crystalline state is first absorbed into absorbent material which is then placed in physical contact with the surface. In a second example, the absorbent material is placed in physical contact with the surface and then the liquid that solidifies without forming a crystalline state is absorbed into it. Additional liquid may be supplied to the absorbent material over time and/or when the absorbent material is moved to a different location. Optionally, the temperature of the absorbent material is brought above the solid to liquid transition temperature by terminating cooling of the absorbent material. The temperature of the absorbent material then rises to ambient temperature. Alternately or additionally, the temperature of the absorbent material is brought above the solid to liquid transition temperature by heating the absorbent material.

Optionally the method further includes dissipating heat generated during the cooling. Further optionally, dissipating heat generated during the cooling includes at least one of:

1. Circulating a coolant through at least one channel running through a heat sink;

2. Blowing air on fins of a heat sink using a fan;

3. Expanding a refrigerant in an evaporator within a heat sink; and

4. Applying a second fluid to the exterior of a thermal control element.

VIII. Mobile System

In some embodiments of the invention, multiple adherent devices are combined in a system capable of moving upon a surface (denoted herein a mobile system). Optionally, each adherent device is capable of adhering to surfaces having varying inclines and surfaces, making the mobile system capable of motion upon a wide variety of surfaces, including but not limited to the bottom of a horizontal surface such as a ceiling.

The mobile system includes multiple adherent devices, a motor assembly and control circuitry. The mobile system may additionally include other hardware elements required by the specific configuration of the mobile system (e.g. as pumps, reservoirs, power sources etc.) but may be easily incorporated into the mobile device. The adherent devices may be placed on surfaces at any orientation, as illustrated in FIGS. 5A-5E. Additionally, some of the adherent devices may be one surface and other adherent devices may be on another surface, permitting the mobile system to move between separated surfaces.

Reference is now made to FIG. 8, which is a simplified schematic diagram of a mobile system, according to an exemplary embodiment of the invention. FIG. 8 shows a non-limiting example in which adherent devices 810.1-810.4 are located on a single flat vertical surface 840. In the non-limiting example of FIG. 8, mobile system 800 has four adherent devices 810.1-810.4. Alternate implementations may include two, three or more than four adherent devices. For clarity, other hardware elements such as pumps, reservoirs, power sources etc. are not shown.

Motor assembly 820 moves adherent devices 810.1-810.4 on the surface based on signals provided by control circuitry 830.

1. Adherent devices - Adherent devices 810.1-810.4 may be implemented according to any of the embodiments described above. Each adherent device includes at least an absorbent material able to absorb a liquid and to be positioned in physical contact with a surface and a thermal control element for cooling the absorbent material to a temperature below the liquid to solid transition temperature of the liquid.

2. Motor assembly - The motor assembly moves the adherent devices upon the surface based on control signals from the control circuitry. The motor assembly, its connections to adherent devices 810.1-810.4 and the way it moves adherent devices 810.1-810.4 may be implemented by any means known in the art.

3. Control circuitry - Control circuitry 830 controls the operation of the mobile device. The control circuitry may include one or more processing units and at least one internal memory for storing code instructions to be executed by the processing unit(s). The control circuitry may be centralized in a single location or dispersed in multiple locations within the mobile device. Control functions performed by the controlling circuitry may include but are not limited to:

• Controlling the motor assembly, and in particular the locations to which it moves the adherent devices.

• Controlling the operation of the thermal control elements to obtain the desired respective temperatures of the absorbent materials. This enables the adhering and releasing the adherent devices independently.

• Controlling heat dissipation from the adherent devices.

Reference is now made to FIG. 9, which is a simplified flowchart of a method for moving a mobile system upon a surface according to embodiments of the invention.

In 910 at least one of the adherent devices is detached from the surface. Other adherent devices remain adhered to the surface so that the mobile system stays attached to the surface. In 920 the detached adherent device(s) are repositioned by the motor assembly at their new locations. In 930, the repositioned adherent device(s) are readhered to the surface.

By performing these processes iteratively, the mobile device may move along a surface and/or between surfaces in a controllable manner.

Optionally, detaching an adherent device from the surface includes thawing a liquid frozen within the respective absorbent material by adjusting the temperature of the respective thermal control element.

Optionally, re-adhering an adherent device to the surface includes freezing a liquid absorbed within the respective absorbent material by adjusting the temperature of the respective thermal control element.

Optionally, at least one of the thermal control elements includes at least one TEC.

Optionally, at least one of the thermal control elements includes a refrigeration compression system.

Optionally, at least one of the thermal control elements includes: a. A heat exchanger for dissipating heat from the liquid absorbed in the absorbent material to a fluid at a temperature lower than the liquid to solid transition temperature; b. A reservoir for containing the fluid; and c. A circulator for circulating the fluid between the heat exchanger and the reservoir.

Optionally, the thermal control elements are thermally coupled to respective heat sinks and heat is dissipated from at least one of the thermal control elements by at least one of: a. Circulating a coolant through at least one channel running through the heat sink; b. Blowing air on fins of the heat sink; and c. Expanding a refrigerant in an evaporator within the heat sink.

Optionally, heat generated during the cooling is dissipated by applying a fluid to the exterior of a thermal control element. The fluid applied to the exterior of the thermal control unit and the fluid circulated in a thermal control unit heat exchanger may or may not be the same fluid.

Optionally, the absorbent material is able to flexibly conform to a shape of the surface. Optionally, the mobile system includes at least one receptacle for holding the liquid and at least one pump for supplying the liquid to the absorbent materials.

Optionally, the mobile system is configured to move upon the bottom of a surface.

Reference is now made to FIG. 10, which is a simplified illustration of an adherent device attached to a robotic arm, according to an exemplary embodiment of the invention. Robotic arm 1000 includes four sections 1010.1-1010.4. Adherent device 1020 is attached to section 1010.1. The robotic arm may be manipulated by the motor assembly by any means known in the art in order to position the adherent devices at the desired locations.

Reference is now made to FIG. 11, which is a simplified illustration of adherent devices mounted on a belt, according to an exemplary embodiment of the invention. Adherent devices 1100.1-1100.12 are attached to the exterior of belt 1110. When one or more of the adherent devices are released from the surface the motor assembly (not shown) is able to rotate the belt. This brings other adherent devices at the other side of the belt in contact with the surface, where they are re-adhered. Repeating this process iteratively moves the mobile device on the surface.

It is expected that during the life of a patent maturing from this application many relevant absorbent materials, cooling devices, heat sinks, heat exchangers, crystalline materials, non-crystalline materials, refrigerants and coolants will be developed and the scope of the terms absorbent material, thermal control element, heat sinks, heat exchanger, liquid, non-crystalline material, fluid, refrigerant and coolant is intended to include all such new technologies a priori.

As used herein, the terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

As used herein, the term “consisting of’ means “including and limited to”.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

As used herein the term "method" refers to techniques and procedures for accomplishing a given task. Although specific embodiments of the invention have been described herein, many alternatives, modifications and variations may be apparent to those skilled in the art. All alternatives that fall within the broad scope of the appended claims are embraced herein.

Features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately.

Features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Although the present disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, this application intends to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

It is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways.

All references (e.g., publications, patents, patent applications) mentioned in this specification are herein incorporated in their entirety by reference into the specification, e.g., as if each individual publication, patent, or patent application was individually indicated to be incorporated herein by reference. Citation or identification of any reference in this application should not be construed as an admission that such reference is available as prior art to the present disclosure. In addition, any priority document(s) and/or documents related to this application (e.g., co-filed) are hereby incorporated herein by reference in its/their entirety.

Where section headings are used in this document, they should not be interpreted as necessarily limiting.