FIELD OF THE INVENTION

Provided herein are methods and devices for determining at least one parameter associated with applying a physical force on a fastener and monitoring the status thereof, comprising the use of at least one sensing element, wherein said sensing element comprises an assembly of nanoparticles being in electric contact with conductive electrodes.

BACKGROUND OF THE INVENTION

Bolts tightening devices, such as various forms of washers, are used to tighten a bolt and to secure its connections. These bolt tighteners are typically in the form of a circular ring that surrounds the bolt and is thus coupled thereto.

Bolts tightening devices can be critical for some applications, for example construction and industrial manufacturing equipment. Undesired related issues of bolt tighteners can include over- tightening, under-tightening and un-evenness of tightening. Incorrect bolt tightening can result in material deformation over time which can damage the bolt and can lead to leaks, costly downtime, and potential safety hazards. In many cases, the use of a torque meter is recommended during tightening of bolts, yet it can be challenging to monitor compliance with this recommendation. In addition, bolts tend to loosen over time due to vibration or thermal stress under certain circumstances.

Currently there are a few available solutions that deploy load cells and strain gauges that are designed as a washer and enable torque monitoring upon tightening and continuous monitoring of a clamp load, over time. These solutions are not widely adopted due to their high price, complexity of wiring of an electrical sampling circuit, and their high energy consumption, which hinders continuous wireless monitoring thereof.

Visual solutions are also available. These solutions change an indicator color upon tension changes. The main drawbacks of these solutions include a lack of resolution, the need to inspect visually, and lack of remote monitoring.

International Pub. No. WO 2019/116212 is directed towards a method for determining a fluid pressure parameter related to a fluid located within a fluid conduit, the method may include measuring one or more resistances of one or more nanoparticle based sensing elements to provide sensed information; wherein the one or more nanoparticle based sensing elements comprise nanometric particles having an electrical resistance that is responsive to at least one out of pressure and temperature; wherein the one or more nanoparticle based sensing elements are printed between conductive electrodes, wherein the conductive electrodes are either printed on an exterior of the fluid conduit or are formed on a substrate that is attached to the exterior of the fluid conduit; and determining, based on the sensed information, the fluid pressure parameter.

There remains an unmet need for a simple, cost effective, low energy consuming solution to enable real-time fastener tightening evaluation, as well as continuous monitoring of fastener tightness, evenness, load distribution, and clamp load changes, over time.

SUMMARY OF THE INVENTION

The present invention provides methods and devices for determining at least one parameter associated with applying a physical force on a fastener and monitoring the status thereof, over time.

According to one aspect, there is provided a fastener tightening device comprising: at least two washers, and at least one sensing element printed on or adhered to an external surface of at least one of the at least two washers, wherein at least one of the at least two washers comprises a spring mechanism, wherein the at least one sensing element comprises an assembly of nanoparticles being in electric contact with conductive electrodes, wherein the fastener tightening device is configured to be coupled to a fastener, and wherein the nanoparticles have an electrical resistance that is responsive to the application of pressure and/or force applied by the fastener on the fastener tightening device, so that the fastener tightening device is configured to measure a resistance of the assembly of nanoparticles, and thereby to determine a status of the fastener under applied pressure and/or force.

According to some embodiments, each one of the at least two washers is canonically shaped and extends between a concave surface and a convex surface, wherein the at least one sensing element is printed on or adhered to the concave surface of a first washer, wherein the convex surface of a second washer is adhered or attached to the concave surface of the first washer and/or to at least a portion of the at least one sensing element, so that the sensing element is disposed between the first and the second washers. According to further embodiments, each one of the at least two washers is a Belleville washer. According to some embodiments, at least one of the at least two washers is a canonically shaped washer and extends between a concave surface and a convex surface, wherein at least one of the at least two washers is a flat washer, wherein the at least one sensing element is printed on or adhered to a surface of the canonically shaped washer, and wherein the flat washer is adhered or attached to the canonically shaped washer and/or to at least a portion of the at least one sensing element, so that the sensing element is disposed between the flat and the canonically shaped washers. According to further embodiments, the canonically shaped washer is a Belleville washer.

According to some embodiments, the at least one sensing element is printed on the at least one washer, or is provided on a substrate which is adhered to the at least one washer. According to further embodiments, the fastener tightening device comprises a substrate which is a substantially flexible substrate being made of an electrically insulating polymeric material selected from the group consisting of polyimide, polyamide, polyimine, polyethylene, polyester, polydimethylsiloxane, polyvinyl chloride, and polystyrene.

According to some embodiments, the fastener tightening device further comprises at least one circumferential spacer which is placed between the at least two washers.

According to some embodiments, the fastener tightening device comprises a plurality of washers and sensing elements, wherein at least one sensing element is disposed between each two consecutive washers.

According to some embodiments, the nanoparticles comprise gold (Au) nanoparticles. According to some embodiments, the nanoparticles are capped with an organic coating, wherein said organic coating is selected from the group consisting of: alkylthiols, arylthiols, alkylarylthiols, alkenyl thiols, alkynyl thiols, cycloalkyl thiols, heterocyclyl thiols, heteroaryl thiols, alkylthiolates, alkenyl thiolates, alkynyl thiolates, cycloalkyl thiolates, heterocyclyl thiolates, heteroaryl thiolates, co-functionalized alkanethiolates, arenethiolates, (co - mercaptopropyl)tri-methyloxysilane, dialkyl disulfides and combinations thereof.

According to some embodiments, the assembly of nanoparticles comprises a monolayer of nanoparticles or multiple layers of nanoparticles.

According to some embodiments, the fastener tightening device is characterized by having a gauge factor greater than about 25.

According to some embodiments, the at least one sensing element is characterized by having a resistance greater than about 140 Kohm. According to another aspect, there is provided a method for detecting and/or monitoring a fastener status, the method comprising: (a) coupling the fastener tightening device as disclosed herein above to a fastener, wherein the fastener is coupled to an element; (b) measuring a resistance of the assembly of nanoparticles from the sensing element of the fastener tightening device during and/or following the application of a force on the fastener, and providing sensed information, and (c) determining, based on the sensed information, at least one fastener parameter that is indicative of the status of the fastener and/or of a process.

According to some embodiments, the at least one fastener parameter is selected from the group consisting of a fastener's tightness, evenness, load distribution, clamp load changes over time, pressure, temperature, and combinations thereof.

According to some embodiments, the step (c) further comprises determining, based on the sensed information, at least one element parameter that is indicative of the status of the element. According to further embodiments, the at least one element parameter is selected from the group consisting of boulted joints alignment, closing or opening percentage of a valve, cable load increase or decrease, and combinations thereof.

According to some embodiments, the step (c) further comprises outputting data representative of the at least one fastener and/or element parameter(s) to a remote destinated device.

According to some embodiments, the fastener tightening device is in operative communication with a control unit, wherein said control unit is configured to determine or calculate the resistance of the assembly of nanoparticles from the sensing element. According to further embodiments, the method further comprises monitoring parameters thresholds and patterns, and optionally providing alerts, based on the determination of the at least one fastener and/or element parameters.

According to some embodiments, the fastener tightening device is battery operated, and wherein the sensed information is transmitted wirelessly.

Certain embodiments of the present invention may include some, all, or none of the above advantages. Further advantages may be readily apparent to those skilled in the art from the figures, descriptions, and claims included herein. Aspects and embodiments of the invention are further described in the specification herein below and in the appended claims.

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, but not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other advantages or improvements.

BRIEF DESCRIPTION OF THE FIGURES

Some embodiments of the invention are described herein with reference to the accompanying figures. The description, together with the figures, makes apparent to a person having ordinary skill in the art how some embodiments may be practiced. The figures are for the purpose of illustrative description and no attempt is made to show structural details of an embodiment in more detail than is necessary for a fundamental understanding of the invention. For the sake of clarity, some objects depicted in the figures are not to scale.

In the Figures:

Figs. 1A-B illustrate a Belleville washer which is a part of a fastener tightening device: a top view (Fig. 1A), and a side view (Fig. IB), according to some embodiments of the present invention.

Fig. 1C illustrates a sensing element which is a part of a fastener tightening device, according to some embodiments of the present invention.

Fig. 2A shows a photograph of a circumferential spacer which is a part of the fastener tightening device, according to some embodiments of the present invention.

Fig. 2B shows a photograph of the fastener tightening device, according to some embodiments of the present invention.

Fig. 3 shows a flowchart of method 200 for monitoring a fastener status, according to some embodiments of the present invention.

Fig. 4A shows a photograph of a sensing element adhered to a Belleville washer.

Fig. 4B shows a photograph of a fastener tightening device consisting of two Belleville washers stacked one over the other, and the sensing element of Fig. 4A disposed therebetween.

Fig. 4C represents the response of sensing elements of Figs. 4A-B to three load cycles. DETAILED DESCRIPTION

The present invention provides methods and devices for determining at least one parameter associated with applying physical force on a fastener and monitoring the status of the fastener, during time. The invention makes use of a combination of at least one sensing element printed on or adhered to a part of a fastener tightening device, such as but not limited to, a Belleville washer, and measuring physical force (e.g., load, torque, etc.) applied thereon, over time.

In the following description, various aspects of the disclosure will be described. For the purpose of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the different aspects of the disclosure. However, it will also be apparent to one skilled in the art that the disclosure may be practiced without specific details being presented herein. Furthermore, well-known features may be omitted or simplified in order not to obscure the disclosure. In the figures, like reference numerals refer to like parts throughout.

The present investors have discovered that by combining high strain sensitivity sensors based on nanoparticles with washers (e.g., Bellville washer), a new device can be proposed to enable a simple, cost effective, low energy consuming solution to enable real-time fastener tightening evaluation, as well as continuous monitoring of fastener tightness, evenness, load distribution, and clamp load changes, over time

Reference is now made to Figs. 1A-2B. Figs. 1A-B illustrate a Belleville washer which is a part of a fastener tightening device: a top view (Fig. 1A), and a side view (Fig. IB), according to some embodiments of the present invention. Fig. 1C illustrates a sensing element which is a part of a fastener tightening device, according to some embodiments of the present invention. Fig. 2A shows a photograph of a circumferential spacer which is a part of the fastener tightening device, according to some embodiments of the present invention. Fig. 2B shows a photograph of the fastener tightening device, according to some embodiments According to a first aspect, there is provided a fastener tightening device 100 configured to interact with a fastener.

According to some embodiments, the fastener tightening device 100 comprises at least one washer 110 which comprises a spring mechanism. According to further embodiments, the fastener tightening device 100 comprises at least two washers 110, wherein at least one of the at least two washers 110 comprises a spring mechanism. According to still further embodiments, the fastener tightening device 100 comprises at least two washers 110, wherein each one of the at least two washers 110 comprises a spring mechanism.

The term “spring mechanism”, as used herein, refers in some embodiments to an elastic object that stores mechanical energy and can act as a loaded spring, so that when an external force is applied thereon the shape of the elastic object can deform, and when the external force is removed therefrom the elastic object can return to its original shape . It is to be understood that the term “spring mechanism” is meant to encompass also a spring-like mechanism, for example, provided by a particular shape of the washer, such as, inter alia, the frusto-conical shape of the Bellville washer.

According to some embodiments, the fastener tightening device 100 comprises at least one washer 110 which is preferably a Bellville washer. It is to be understood that other suitable washers known in the art can also be used. According to further embodiments, the fastener tightening device 100 comprises at least two Bellville washers 110. According to some embodiments, the at least one Bellville washer 110 comprise spring-like characteristics due to its shape, and therefore inherently comprises a spring mechanism. According to other embodiments, the fastener tightening device 100 comprises at least one flat washer 110 and at least one Bellville washer.

According to some embodiments, the fastener tightening device 100 comprises at least one Bellville washer 110, which comprises a central hole 114 through which a fastener can be placed. In further embodiments, the fastener can be selected from a bolt, a screw, a nail, a nut, a spring, and the like. Each possibility represents a different embodiment. In still further embodiments, the fastener is a bolt. The Bellville washer 110 comprises a central hole 114 having an inner diameter DI and an external diameter D2, wherein D2 is greater than DI. The Bellville washer 110 is further canonically shaped and extends between a concave surface 112 and a convex surface 116, as illustrated at Fig. IB. Said canonically shape makes the Bellville washer particularly effective at handling heavy loads due to its spring-like characteristics.

Upon utilization, the Belleville washer 110 is coupled to a bolt, so that the bolt is inserted in the center of the central hole 114 thereof. The main utilization of a Belleville washer is to absorb loads and vibrations, by acting as a spring. When a load is applied on a Belleville washer, the washer is able to compress due to its canonical shape, and therefore act as a spring. At the same time, the Belleville washer exerts an equal amount of force against the object. Therefore, Belleville washers can handle larger, heavier loads that aren’t possible with conventional washers. Depending on the application, multiple Belleville washers can be used to create greater resistance against heavy loads to form a stack of Belleville washers, which acts as multiple springs, each of which acts against the object.

According to some embodiments, the fastener tightening device 100 comprises at least one sensing element 120 printed on or adhered to the concave surface 112 of the at least one washer 110.

As used herein, the terms “sensing elements”, “nanoparticle-based sensors”, and “nanoparticle sensors” are interchangeable, and refer to the sensing elements comprising an assembly of nanometric particles, as presented herein.

The sensing element 120 is based on an assembly of nanometric particles. The nanoparticles can be metallic. Suitable metallic nanoparticles within the scope of the present invention include, but are not limited to Au, Ag, Ni, Co, Pt, Pd, Cu, Al, and combinations thereof, including metal alloys such as, but not limited to Au/Ag, Au/Cu, Au/Ag/Cu, Au/Pt, Au/Pd, Au/Ag/Cu/Pd, Pt/Rh, Ni/Co, and Pt/Ni/Fe. Each possibility represents a separate embodiment of the present invention. In some exemplary embodiments, the nanoparticles are gold (Au) nanoparticles.

The high sensitivity of the nanoparticle-based sensing elements suitable for use in the methods of the present invention and wide dynamic range thereof, enable detection of very small pressure changes (which is not possible with current strain sensing technologies) over a wide range of pressures with high accuracy and without the need for additional elements. Additionally, the nanoparticle-based sensing elements are characterized by particularly rapid response times, thereby allowing immediate detection of pressure changes, due to the application of various forms of force.

The change in the measured property (e.g., electrical resistance) is determined by the change in the inter-particle distance between the nanoparticles within the nanoparticles assembly, said nanoparticles being neighboring nanoparticles of the same nanoparticles layer and/or nanoparticles of adjacent nanoparticle layers within the nanoparticles assembly. In some embodiments, the electrical signal is produced by the sensing elements by the swelling of the assembly of nanoparticles in response to changes in pressure. As used herein, the term “swelling” refers to an increase of the average inter-particle distance in the assembly of nanoparticles. In other embodiments, the electrical signal is produced by the aggregation of the assembly of nanoparticles in response to changes in pressure. As used herein, the term “aggregation” refers to a decrease of the average inter-particle distance in the assembly of capped nanoparticles.

According to some embodiments, the interparticle distance is highly affected by lateral strain/pressure and/or torque (i.e., rotational force).

According to some embodiments, the metallic nanoparticles are capped with an organic coating, for example, to ensure long time stability and/or to enhance the sensor signal. The organic coating of the metallic nanoparticles comprises a monolayer or multilayers of organic molecules. Suitable coating includes, but is not limited to alkylthiols, e.g., alkylthiols with C3- C24 chains, arylthiols, alkylarylthiols, alkenyl thiols, alkynyl thiols, cycloalkyl thiols, heterocyclyl thiols, heteroaryl thiols, alkylthiolates, alkenyl thiolates, alkynyl thiolates, cycloalkyl thiolates, heterocyclyl thiolates, heteroaryl thiolates, co-functionalized alkanethiolates, arenethiolates, (co -mercaptopropyl)tri-methyloxysilane, dialkyl disulfides and combinations thereof. Each possibility represents a separate embodiment of the present invention. In various embodiments, the organic coating is characterized by a thickness ranging from about 1 nm to about 1000 nm. In further various embodiments, the organic coating is characterized by a thickness ranging from about 1 nm to about 250 nm, about 50 nm to about 750 nm, about 1 nm to about 500 nm, or about 100 nm to about 800 nm. Each possibility represents a different embodiment of the present invention.

In some embodiments, the sensing element 120 further comprises a plurality of conducting electrodes. In certain such embodiments, the nanoparticle assembly is coupled to said electrodes, i.e., being in electric contact therewith, thereby enabling the measurement of the signals generated by the nanoparticle assembly. The sensing element can include two, three or more electrodes. Different configurations of the electrodes may be fabricated as is known in the art. The distance between adjacent electrodes defines the sensing area. Typically, the distance between adjacent electrodes in each sensing element ranges between about 0.01 mm to about 5 mm. In some embodiments, the sensing element comprises interdigitated electrodes. The nanoparticle assembly can be disposed upon the electrodes, covering at least a portion of each electrode, or between the electrodes. Each possibility represents a separate embodiment of the invention. The conducing electrodes may comprise metals such as Au, Ag, Pt, Cu, and alloys and combinations thereof, and may further be connected by interconnecting wiring.

According to some embodiments, the nanoparticle-based sensing element can be printed on or adhered to the concave surface 112 of the at least one washer 110 of the device 100. Alternatively, the nanoparticles can be supported on an essentially flexible substrate. Said substrate can be adhered to the concave surface 112 of the at least one washer 110 of the fastener tightening device 100.

The substrate suitable for use in the sensing elements implemented in the methods of the present invention should be substantially flexible. According to some embodiments, the substantially flexible substrate is made of an electrically insulating polymeric material. Such substantially flexible substrates include stretchable substrates as is known in the art, e.g., polymers which may be polyimide (e.g. Kapton ®), polyamide, polyimine (e.g. polyethylenimine), polyethylene, polyester (e.g. Mylar ®, polyethylene terephthalate, polyethylene naphthalate), polydimethylsiloxane, polyvinyl chloride (PVC), polystyrene and the like; or silicon-based substrates, such as, silicon dioxide or Si rubber. Each possibility represents a separate embodiment of the present invention.

The substantially flexible substrate can have any desirable geometry, which is compatible with the washer and the nanoparticles assembly shape. The thickness of the substrate can range from about 1 micrometer to about 1000 micrometers. According to some embodiments, the thickness of the substrate is in the range of about 1 micrometer to about 100 micrometers, about 100 micrometers to about 200 micrometers, about 200 micrometers to about 300 micrometers, about 300 micrometers to about 400 micrometers, about 400 micrometers to about 500 micrometers, about 500 micrometers to about 600 micrometers, about 600 micrometers to about 800 micrometers, or about 800 micrometers to about 1000 micrometers. Each possibility represents a separate embodiment of the present invention. According to further embodiments, the thickness of the substrate is in the range of about 5 micrometers to about 500 micrometers.

According to some currently preferred embodiments, the sensing element 120 has a thin-film structure. The thin film configuration of the nanoparticle sensors prevents or substantially diminishes delamination of the sensing elements from the surface of the washer which results from either shear stresses induced by lateral strains associated with the pressure changes and/or normal stresses induced by the elastic bending force of the sensing element in the case of curved surfaces.

The nanoparticles within said sensing element 120 can be arranged in well-ordered two- or three-dimensional assemblies, i.e., the assembly of nanoparticles can include a monolayer or multiple layer of nanoparticles. The nanoparticles assembly can have any shape or surface area suitable for attaching the sensing element to the washer. The nanoparticles assembly can further have a specific pattern, which can be disposed between a pair of conductive electrodes. The electrical contact between the nanoparticles assembly and the electrodes can be obtained with or without printing any part of the pattern on one or more conductive electrodes of the pair.

The assembly of nanoparticles can be formed on the substrate, the conductive electrodes, and/or the concave surface 112 of the at least one washer 110 by means of any technique suitable for depositing nanoparticle inks. Non-limiting examples of suitable deposition techniques include inject printer printing, 3D printing, random deposition from solution of nanoparticles on solid surfaces, field-enhanced or molecular-interaction-induced deposition from solution of nanoparticles on solid surfaces, Langmuir-Blodgett or Langmuir- Schaefer techniques, soft lithographic techniques, such as micro-contact printing (mCP), replica molding, micro-molding in capillaries (MIMIC), and micro-transfer molding (mTM), and combinations thereof. Each possibility represents a separate embodiment of the present invention.

The conducting electrodes can be formed on the concave surface 112 of the at least one washer 110 or on the substrate by depositing a conductive ink, such as for example, AgCite from Nanodimension, by inject printing or 3D printing. Photonic sintering (e.g., by Xenon) can be performed in order to sinter the electrodes and make them conductive.

The sensing element 120 can further include a protective coating. The protective coating can be configured to protect the nanoparticles assembly from external stimuli, such as, for example, humidity or adsorption of volatile organic compounds. The protective coating can further be used to ensure structural and mechanical integrity of the nanoparticles assembly during prolonged sensing periods, in particular where the nanoparticles are not supported on a substrate or wherein the sensing elements are attached directly to the washer 110 and not through the nanoparticles assembly. Typically, the protective coating comprises a polymer such as, but not limited to: polydimethylsiloxane (PDMS), polyurethane, parylene, fluoropolymer, and/or other suitable materials such as acrylic fibers, epoxy, silicone, combinations thereof, or any other suitable polymer/material that is known in the art.

According to specific embodiments, the at least one sensing element 120 comprises a sensing layer 122 consisting of an assembly of nanometric particles as disclosed herein above, which is electrically coupled to a plurality of conducting electrodes 124, which is supported on a flexible substrate 126. Said substrate 126 can be adhered to the concave surface 112 of the at least one washer 110 of the fastener tightening device 100. According to further embodiments, the assembly of nanometric particles comprises Au, the conducting electrodes comprise Cu coated with Au, and the substrate comprises Kapton.

According to some embodiments, the fastener tightening device 100 comprises at least one Belleville washer 110 and at least one flat washer, wherein the at least one sensing element 120 is printed on or adhered to the concave surface 112 of the at least one Belleville washer 110, and wherein the flat washer is coupled to the concave surface 112 of the at least one Belleville washer 110 and optionally to at least a part of the at least one sensing element 120. According to other embodiments, the fastener tightening device 100 comprises at least one Belleville washer 110 and at least one flat washer, wherein the at least one sensing element 120 is printed on or adhered to the convex surface 116 of the at least one Belleville washer 110, and wherein the flat washer is coupled to the convex surface 116 of the at least one Belleville washer 110 and optionally to at least a part of the at least one sensing element 120.

Advantageously, the flat washer as disclosed herein above can act as a protective washer protecting the at least one sensing element 120, as well as a load distributor so that the load applied by the fastener on the fastener tightening device 100 is not concentrated on the lips of the central hole 114, but rather on the bulk portion thereof surrounding the hole, thus affectively distributing the load applied thereon.

According to alternative embodiments, the fastener tightening device 100 comprises at least two Belleville washer 110, a first washer 110A and a second washer HOB, as illustrated at Fig. 2B, wherein the at least one sensing element 120 is disposed therebetween. In further embodiments, the at least one sensing element 120 is printed on or adhered to the concave surface 112 of the first washer 110A, wherein the second washer HOB is adhered or attached to the first washer and/or to at least a portion of the at least one sensing element 120, so that the sensing element 120 is disposed or stacked or retained or 'sandwiched' between the first and the second washers. In still further embodiments, the convex surface 116 of the second washer 110B is adhered or attached to the concave surface 112 of the first washer 110A and/or to at least a portion of the at least one sensing element 120.

In further embodiments, at least two Belleville washers 110 are stacked one over the other, and wherein the at least one sensing element 120 is disposed or stacked or retained therebetween. In other embodiments, at least one sensing element 120 or a portion thereof is printed on or adhered to the concave surface 112 of the first washer 110A, wherein at least one sensing element 120 or a portion thereof is printed on or adhered to the convex surface 116 of the second washer HOB, and wherein the first and the second washers are coupled to one another so that their respective sensing elements 120 are facing each other and/or are in contact with one another.

According to some embodiments, the fastener tightening device 100 comprises a plurality of Belleville washers 110 stacked one over the other and a plurality of sensing elements 120, wherein at least one sensing element 120 is disposed or retained between each two consecutive washers, as disclosed therein above. In further embodiments, at least one sensing element 120 of the plurality of sensing elements 120 is disposed or retained alternately between the plurality of washers, so that each two consecutive washers 110 are separated by the at least one sensing element 120 printed on or adhered to at least one surface thereof.

During operation and/or utilization, the fastener tightening device 100 is coupled to a fastener (e.g., a bolt), so that the fastener is inserted into the center of the central hole 114 thereof. Then, various forms of forces (stresses, loads, etc.) may be inflicted on the fastener, and as a result, on the fastener tightening device 100 as well. Advantageously, it is contemplated in some embodiments, that structure of the fastener tightening device 100 as disclosed herein above, comprising at least two Belleville washers 110 stacked one over the other, or at least one Belleville washer 110 and at least one flat washer, and at least one sensing element 120 disposed or retained therebetween, enables to maintain the active area of the sensing element 120 protected from mechanical wear associated from the loads inflicted on the fastener tightening device 100 during operation, and therefore can enhance the sensitivity of the sensing element 120 and contribute to its continuous proper operation.

According to some embodiments, the fastener tightening device 100 further comprises at least one circumferential spacer 130, as shown for example in Fig. 2A, which is placed between the first and the second washers (shown in Fig. 2B), so that the spacer 130 may protect the sensing element 120 disposed therebetween and optionally any electrical wires from direct compressive loads, during operation and/or utilization thereof. According to some embodiments, the circumferential spacer 130 comprises teeth-like inner protrusions (not shown), configured to prevent friction between the first and the second washers.

According to some embodiments, the fastener tightening device 100 is in operative communication with a control system, in order to determine sensed information. The control system can comprise electronic circuity configured to detect or receive electrical signals from the sensing element 120, via wired or wireless communication. In some embodiments, the control system comprises electronic circuity configured to detect the electrical signals of the sensing element 120. The electronic circuity for measuring the electrical signal can comprise at least one of: a printed control board (PCB), provided with a central processing unit (CPU) or a processor, a memory, a real-time clock (RTC), a battery or other power source, and a communication module, wherein the CPU or the processor applies voltage to the sensing elements and calculates the resulting resistance.

According to some embodiments, the fastener tightening device 100 is in electrical communication with a power source (e.g., battery) configured to provide power thereto. According to further embodiments, the fastener tightening device 100 is battery operated.

According to some embodiments, the fastener tightening device 100 is configured to be coupled to a fastener (e.g., a bolt) as disclosed herein above, and to measure a resistance of the assembly of nanoparticles from the sensing element 120, and to provide sensed information to the control system. The sensing element 120 comprise nanometric particles as disclosed herein above, having an electrical resistance that is responsive to the application of pressure and/or force (e.g., load, torque, etc.). The utilization of the fastener tightening device 100 as disclosed herein above enables to determine, based on the sensed information (by the control system), the status of the fastener, which includes at least one fastener parameter. The at least one fastener parameter can be indicative of the tightness of the fastener, evenness, load distribution, clamp load changes over time, combinations thereof, and the like. Each possibility represents a different embodiment.

According to some embodiments, the control system is configured to determine or calculate the resistance of the assembly of nanoparticles from the sensing element 120, and to determine based on this data, the status of the at least one fastener parameter under applied pressure and/or force, as disclosed herein above. The control system can output data to a remote destinated device (e.g., a computer, a tablet, a smartphone, etc.) via a wired and/or wireless communication module (e.g., Bluetooth, WiFi, etc.), and thus to provide indications to a user. According to some embodiments, the fastener tightening device 100 is configured to wirelessly transmit data to the control system.

According to some embodiments, the fastener tightening device 100 is characterized by having a gauge factor greater than about 10, 25, 50, 75, 90, 100, or more. According to further embodiments, the fastener tightening device 100 is characterized by having a gauge factor greater than about 25, optionally greater than about 50, or alternatively greater than about 90. According to still further embodiments, the fastener tightening device 100 is characterized by having a gauge factor selected from the range of about 5-150, alternatively 10-100, or optionally 25-95. Each possibility represent a different embodiment. According to some embodiments, the fastener tightening device 100 is characterized by having a gauge factor of about a 100 or less.

According to some embodiments, the sensing element 120 of the fastener tightening device 100 of the present invention is characterized by having a resistance greater than about 50 Kohm, optionally greater than about 100 Kohm, or alternatively greater than about 140 Kohm. According to further embodiments, the sensing element 120 of the fastener tightening device 100 is characterized by having a resistance selected from the range of about 100 - 2000 Kohm, optionally about 120 - 1500 Kohm, or alternatively 140 - 1400 Kohm. Each possibility represent a different embodiment. According to still further embodiments, the sensing element 120 of the fastener tightening device 100 is characterized by having a resistance selected from the range of about 140 - 1400 Kohm.

It is contemplated that the gauge factor (i.e., the ratio of relative change in electrical resistance to mechanical strain) of the fastener tightening device 100 of the present invention can reach 100, in comparison to a typical Gauge factor of 2 for conventional metallic strain gauges. In addition, the sensing element of the present invention could have a relatively high resistance (about 140 - 1400 Kohm) which forms a simple resistor. Therefore, it is possible to build a battery-operated fastener tightening device 100 that will sample the sensing element 120 and transmit the data via wireless protocol (e.g., Bluetooth). The power consumption of the sensors can be in the rage of 10s Microamp.

Reference is now made to Fig. 3, illustrating a flowchart of a method 200 for detecting and/or monitoring a fastener status, the method comprises step 202 of providing a fastener tightening device 100 as disclosed herein above, and coupling it to a fastener. The fastener can be coupled or attached to an element (i.e., a flange, valve, cable, lift, chain, crane, etc.), wherein the fastener is configured to fix and/or tighten said element in place, or attach/coupled it to another element.

Step 202 can further include applying a pressure and/or a force (e.g., load, torque, etc.) onto the fastener, and optionally onto the fastener tightening device 100. As a result from the application of pressure and/or force applied on the fastener during the utilization thereof, the fastener applies pressure and/or force onto the fastener tightening device 100.

The method further comprises step 204 of measuring a resistance of the assembly of nanoparticles from the sensing element 120 of the fastener tightening device 100, and providing sensed information, optionally to a control system. The measuring can be performed under applied pressure and/or force (e.g., load, torque, etc.) onto the fastener and the fastener tightening device 100 in step 202.

The method further comprises step 206 of determining, based on the sensed information, at least one fastener parameter that is indicative of the status of the fastener, under applied pressure and/or force. The at least one fastener parameter can be selected from the group comprising the fastener's tightness, evenness, load distribution, clamp load changes over time, and combinations thereof. Each possibility represents a different embodiment. The determination of the at least one fastener parameter based on the sensed information can be performed by the control system.

According to some embodiments, step 206 of method 200 can further determine, based on the sensed information, at least one element parameter that is related to the element (e.g., flange, valve, cable, etc.) which the fastener is attached or coupled to. The at least one element parameter is selected from the group consisting of: boulted joints alignment, closing or opening percentage of a valve, cable load increase or decrease, and combinations thereof. Each possibility represents a different embodiment. Method 200 can further determine and/or asses the operation status of the element, based on patterns recognition of the at least one element parameter over time. For example, method 200 can determine and/or asses flange and/or valve leakage, uneven load distribution on cable systems, and the like. The determination and/or assessment of the at least one element parameter based on the sensed information can be performed by the control system.

According to some embodiments, step 206 of method 200 can further determine, based on the sensed information, parameters that are related to a process (e.g., pressure, temperature, etc.). The at least one fastener parameter as disclosed herein above can further include pressure and/or temperature related parameters (which can be can be monitored), and as a result to provide indications regarding the status of a process. Process parameters thresholds can be monitored and alerted, based on the determination of the at least one fastener parameter, if at least one certain parameter threshold has been crossed. Process related patterns can be monitored, and abnormalities that are related to a known issue (or an unknown issue), can be alerted to a user as needed.

According to some embodiments, step 206 can further include outputting data representative of the at least one fastener and/or element parameter(s) to a remote destinated device (e.g., a computer, a tablet, a smartphone, etc.).

The term “plurality”, as used herein, means more than one.

The term "about", as used herein, when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of +/-10%, more preferably +/-5%, even more preferably +/-1%, and still more preferably +/-0.1% from the specified value, as such variations are appropriate to the disclosed devices, systems and/or methods.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the patent specification, including definitions, governs. As used herein, the indefinite articles "a" and "an" mean "at least one" or "one or more" unless the context clearly dictates otherwise.

It is appreciated that certain 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 or in any suitable subcombination or as suitable in any other described embodiment of the invention. No feature described in the context of an embodiment is to be considered an essential feature of that embodiment, unless explicitly specified as such.

EXAMPLES

Example 1 - fabrication of a fastener tightening device

A sensing element was fabricated by printing gold nanoparticles encapsulated with organic ligands using a digital print head, to create the sensing layer. The printing was performed on a defined interdigitated electrode (Cu coated with Au) that were evaporated on a Kapton substrate. The final structure of the sensing element is similar to sensing element 120 as disclosed herein above and as is illustrated in Fig. 1C.

To fabricate the fastener tightening device, the sensing element was adhered to the curved surface of a M20 stainless steel Belleville washer using Loctite 9492 as the adhesives, as shown in Fig. 4A. Then, the sensing element was attached to a Belleville washer so that the Kapton layer was facing the Belleville washer. An additional Belleville washer was placed or stacked on the first Belleville washer comprising the nanoparticles-based sensor, as shown in Fig. 4B, so as to form a protective “sandwich” formation that maintains the active area of the sensing element protected from mechanical wear associated from the loads inflicted on the fastener tightening device. The black cable in Fig. 4B seen on the right side is the sensor wiring coming out between the two washers, through a pre-machined groove made in one/or both of the washers.

Example 2 - Torque testing

Rotational motion (torque) was inflicted on the fastener tightening device fabricated at Example 1. The torque was applied with a manual torque meter in cycle steps [N/M] of: 0- >20->40->60->0. Each cycle was repeated for 3 times, as can be seen in Fig. 4C. Each value had a deviation of about ± 5 N/M. The results shown at Fig. 4C demonstrate the high sensitivity of the fastener tightening device to torque. The high response indicates that torques as small as a few N/M can be detected.

It is contemplated that the spring like properties of the washers of the fastener tightening device can also be monitored with this system, since if the flexibility thereof is damaged, the baseline of the sensors may be irreversibly changed.

Although the invention is described in conjunction with specific embodiments thereof, it is evident that numerous alternatives, modifications and variations that are apparent to those skilled in the art may exist. 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 herein. Other embodiments may be practiced, and an embodiment may be carried out in various ways. Accordingly, the invention embraces all such alternatives, modifications and variations that fall within the scope of the appended claims.