Field of the Invention

The invention relates to a battery powered handheld device for use in the medical, for example the dental area, comprising a device housing as well as a battery and a battery chassis. The invention also relates to a charging device for charging the battery powered handheld device according to the invention.

Background Art

In the medical, e.g. dental area, a lot of handheld devices are known. If those handheld devices are battery powered, they may be easy to use, since no power cord needs to be present at the handheld device.

ETS 5 471 129 A discloses a rechargeable light curing apparatus having at least one hand-operated device with a handle and an on/off switch and a recharging unit to which said hand operated device can be mechanically and electrically coupled.

Especially in the medical, e.g. dental area these handheld devices and/or their charging devices may come in contact with fluids for example disinfection fluids. These fluids may cause electrochemical corrosion of electrical contacts, for example of the charging contacts of the device, if a fluid film is created that extends from one electrode to another electrode and if an electrical potential exists between the two electrodes. Sometimes user manuals or labels of battery powered devices give instructions to the user as to avoid liquids and to keep the contacts dry. However, it can be experienced that in current practice, these instructions are not considered or followed in every case. Furthermore, fluid films on the contacts may be present even if these instructions are complied with because fluid films are not necessarily visually observable. For example, by wiping the battery powered device and its charger device with a moist cloth, the remaining liquid film may still be sufficient to cause some weak corrosion, even if the fluid or agent vaporizes after a few minutes. If a longer period of time is considered, the incremental corrosion of the contacts will affect the electrical properties of the contacts and might therefore influence charging time of the device or cause other problems.

Therefore, a need exists to provide a prevention of electro-chemical corrosion of electric contacts, in particular of battery powered handheld devices. EP 1 473 795 Al discloses for example a battery powered hand piece comprising means for allowing charging current to flow but preventing current flow in the opposite direction, or comprising means for sensing a current flow due to fluids present. In this reference it is mentioned that it is rather useful and desirable that the charging contacts are open and easily accessible because placing the battery powered device into the charging station and the charging operation should be easy and quick.

In view of the above mentioned prior art there is still a need for battery powered handheld device with an enhanced protection of the charging contacts. In order to provide more flexibility for the user, there is also a need for providing a battery powered handheld device that can be charged or refilled with energy in several different ways.

Summary of the Invention

According to a first aspect, the invention relates to a battery powered handheld device comprising a device housing, a battery for storing energy for powering the handheld device and a battery chassis, the battery chassis comprising a receiving area for the battery as well as at least one electrical contact for providing an electrical connection to the battery chassis, wherein the contact is arranged such on the battery chassis that it is placed inside of the device housing.

Battery powered handheld devices are frequently used in the medical, e.g. the dental area. Since they usually do not have a power cord, they are easy to use. These handheld devices may provide a variety of functionalities, such as motors, light sources, heat sources or the like. One very often used tool in the dental area are curing lights. They may be used to cure dental materials inside of a patient’s mouth. Those dental curing lights need to fulfill a variety of requirements such as for example easy handling, as mentioned above, but also requirements related to hygiene, safety for the user. It is also advantageous if they are produced cost effectively.

It is further advantageous if the handheld device provides an ergonomic design such that it can be easily grabbed and that it can be easily handled during the use. Examples of an ergonomic design may be that the shape of the device is selected such that it does not provide sharp edges, that the design provides areas for placing the five fingers of a hand, that the materials of the surface of the device are selected such that they have a nice haptic appearance and so on. Another point is that the handheld device should not be too big and too heavy for easy handling.

In order to provide a battery powered handheld device, the device according to the invention provides a battery. In the context of the invention a battery is any means that is able to store energy and to provide energy in the handheld device, when the handheld device is used, e.g. when the light source is activated. The battery may be a built-in battery, it may be a removable battery, it may be a rechargeable battery. Single use batteries may also be used when according safety instructions are being taken care of.

According to the invention, the battery is placed in a battery chassis, which is also part of the battery powered handheld device. The battery chassis holds or carries the battery as well as possibly other components and provides at least one contact that is arranged such on the battery chassis that it is placed inside of the device housing. Thus, the device housing provides a protection of the contacts against environmental influences, such as for example liquids or mechanical impacts. The contact establishes the electrical connection from and to the battery. In particular, the contact establishes the electrical connection between the battery and an electronic circuit (for example a charging and/or security circuit) of the powered handheld device. As will be laid out below it may be used for different purposes. The contact may at least partially be made out of electrically conductive material. It may provide any kind of known shape for electrical contacts, such as for example simple flat metal strip. The battery chassis may particularly provide two contacts for corresponding two contact of the battery.

According to one embodiment of the invention the handheld device comprises a light source. The light source may comprise an LED (light emitting diode) that is configured for emitting light at a wavelength between 450 nm - 495 nm (visible blue light). The light source may be used as a curing light. The use of dental materials that are hardenable by blue light of a wavelength of between about 450 and 500 nm has become common in dentistry. Accordingly, dental light irradiation devices used for hardening such dental materials typically emit light at such wavelengths and typically enable the device to automatically control the light emission for only a pre-selected or pre-selectable time period. Such dental light irradiation device, for example, is available from 3M ESPE, Germany, under the trade designation Elipar™ S10 LED Curing Light. According to another embodiment of the invention the light source may be arranged in the device housing itself and not in the battery chassis. Usually the device housing of a curing light provides an elongated shape with the light exiting the device at its outer most tip. Such a design enables an easy positioning of the curing light device in a patient’s mouth in order to direct the light onto the material that needs to be cured.

According to another embodiment of the invention the battery chassis is detachably attached to the device housing. Thus, it is possible to remove the battery chassis together with the battery (and eventually any other components) from the device housing. This may for example be advantageous when the battery needs to be exchanged or recharged or when any other modifications of the handheld device need to be made.

The electrical contact of the battery powered handheld device may be arranged on the outside of the battery chassis. With such a design it is easily accessible from the outside, when the battery chassis is removed from the device housing. With such a configuration it is for example possible to use the at least one electrical contact on the outside of the battery chassis as charging contacts for charging the battery of the battery powered handheld device.

The electrical contact may furthermore establish an electrical connection between the battery in the battery chassis and the device housing. In other words, the contact provides the electrical connection from the battery to the functionalities in the device housing, for example for powering a light source or the like. Thus, the contact may fulfill two different functions, one being charging contacts, for example when the battery chassis is removed from the device housing and the battery chassis with the battery is positioned on a charging station. The other being establishing an electrical connection between the battery in the battery chassis and the components in the device housing.

The battery chassis may further comprise additional components such as for example a charging circuit and/or a security circuit. A charging circuit may provide the electronic components that are necessary to charge a battery. The charging circuit may also be arranged in the device housing. Since different ways of charging may be used for charging the battery of the handheld device according to the invention, for example inductive charging or direct charging, the charging circuit may enable a charging of the battery independent of the charging method that is selected. In other words, the charging circuit provides electronic for both charging methods. A security circuit may provide electronic components that may be necessary for protecting the device and its user in the case the battery is defect. They are for example required for all lithium ion batteries.

As mentioned above, different ways of charging exist, e.g. inductive charging or direct charging. In order to provide maximum flexibility for a user the battery powered handheld device may provide means for charging the battery that allow different ways of charging. The battery powered handheld device may for example provide contacts for charging the battery directly. These contacts may be the at least one electronic contact arranged on the battery chassis. In this case the contact or contacts need to be easy accessible from the outside. The battery powered handheld device may also provide a charging coil for inductive charging of the battery. The charging coil may for example be positioned inside of the battery chassis or inside the device housing.

According to another embodiment, the interface between the device housing and the battery chassis is sealed to prevent fluids from entering the device. The sealing may be achieved by mechanical means such as for example geometric shapes of the device housing and the battery chassis that interact with each other. An example for such a geometric shape is for example a step shaped interface. In addition, the interface between the device housing and the battery chassis may also provide additional sealing means such as an elastic seal, for example a rubber or foam strip or film.

The battery chassis may be fastened to the device housing through a snap fit connection, a screw connection or any other known mechanical means for connection to components with each other that are detachably attached to each other.

The battery chassis comprises at least one battery cell. It may also provide more than one battery cells, such as for example two, three, four or more battery cells. The more cells are used the more energy in sum is available, the longer the handheld device may be used without charging or changing the batteries can be used. The number of cells used may be limited by the space that is available and the weight of the handheld device. Depending on the electronic circuit used in the battery chassis, the batteries may be arranged in series or in parallel. The battery cells may also for example be single use batteries that cannot be recharged but only exchanged. The battery may be a standard battery (for example according to the standard DIN EN 60086-1 : 2016-07 also referred to as A, AA or AAA battery, respectively) or it may be a built-in battery. The battery may be rechargeable or it may be a one use battery. According to a second aspect, the invention relates to a charging station for charging a battery of a battery powered handheld device according to any of the preceding claims.

The charging device may comprise means for inductively charging the battery as well as means for directly charging the battery.

Brief Description of the Figures

Fig. 1 is a perspective view of a battery powered dental curing light;

Fig. 2 is a partial exploded, perspective view of the handle part of the dental curing light of Figure 1 with a battery chassis;

Fig. 3 is a perspective, transparent view of the battery chassis of Fig. 2;

Fig. 4 is a partial transparent side view of the handle part of the dental curing light of Figure 1;

Fig. 5 is an exploded, perspective view of another embodiment of a battery powered dental curing light;

Fig. 6 is a partial exploded, transparent view of the bottom part of the dental curing light of Figure 5;

Fig. 7 is a perspective, partially transparent view of the battery chassis of Fig. 5 and

Fig. 8 is a perspective view of the battery powered dental curing light of Figures

1 to 4 with a charging station.

Detailed Description of the Invention

In Figure 1 a perspective view of a battery powered medical, dental handheld device, here a curing light 1 is shown. Dental handheld devices usually need to be light in weight in order to be handled easily during the use. They also need to provide an ergonomic shape such that they can easily be grabbed, kept and used. For this purpose, the curing light 1 of Figure 1 provides a handle portion 2 and an operating portion 3. Both portions have a generally circular cross section, wherein the diameter of the cross section of the handle portion 2 is larger than the diameter of the cross section of the operating portion 3.

The operating portion 3 has a generally cylindrical shape. At its outermost tip it provides an angled section 4 that carries a light extracting area 5 pointing in a direction approximately perpendicular to the general extension of the battery powered curing light 1. This design ensures that the light, that needs to be projected onto a specific spot in a patients’ mouth can be directed easily onto this spot by holding the battery powered curing light 1 in a hand and directing the operation portion 3 into the mouth of the patient.

The handle portion 2 has also a generally cylindrical shape. It provides an ergonomic shape by providing no sharp edges and a slightly curved outer surface such that the fingers of a dentist may easily and securely be placed on the handle portion 2. The handle portion 2 further provides a switch 6 for activating and controlling the battery powered handheld device 1. It also provides an indicating area 7 that may display different kind of information to a user such as for example the time for that the curing light 1 was activated. Additional buttons may be present, such as for example a timer button for setting the curing time. All these areas and functions are sealed so that no liquid can enter the curing light 1.

Finally, the dental curing light 1 shown in Figure 1 provides no electrical contacts on its outside. This is a major advantage in the area of battery powered handheld devices, because as already laid out above, there is a risk, especially when the battery powered handheld devices come in contact with liquids, that the electrical contacts corrode, which in the end may lead to a less effective operation of the battery powered handheld device. The battery powered curing light 1 of Figure 1 provides two possibilities for charging, one being an inductive charging and the other being a charging through direct electrical contact. These two options will be described in more details with reference to the following drawings.

Figure 2 is a partial exploded, perspective view of the handle part 2 of the dental curing light 1 of Figure 1. It shows the handle part 2 which provides a two part housing 11 and 12. For the rest of the description the upper housing part 11 will be named housing 11 and the lower housing part 12, carrying the battery 13, will be named battery chassis 12. The housing 11 and the battery chassis 12 are detachably attached or fixed to each other through a snap fit connection that will be described in more detail below with reference to Figure 3. The housing 11 holds all the electronics and functionalities that are necessary for the dental curing light 1, including the light source, the electronic circuits for the switch 6 and the timer 7 as well as a heatsink The battery chassis 12 holds the battery 13 as well as all necessary electrical contacts (will be described with reference to Figure 3). The battery chassis 12 may further hold charging electronics as well as security electronics (not shown in Figure 2). The battery chassis 12 has a generally cylindrical, bottom part, which opens on the side, which is directed towards the housing 11. The opening enables access to the components inside of the battery chassis 12. The battery chassis 12 is closed at the side, which is directed away from the housing 11.

As can be seen in Figure 2, the housing 11 and the battery chassis 12 are adapted in their shape such that they perfectly engage with each to the above described ergonomically shaped handle portion 2 of the handheld device 1. The interface between the housing 11 and the battery chassis 12 may be sealed through known sealing means, such as adapted geometries or additional sealing means in the form of foams or rubbers (not shown in the drawings).

Figure 3 is a perspective, partially transparent view of the battery chassis 12 of Figure 2. As already described above, the battery chassis 12 provides a generally cylindrical bottom part with a closed end as well as an open upper part, which is directed towards the housing 11. The battery chassis 12 holds first of all the battery 13. It further holds a coil 14 that may be used for inductively charging a battery. It also provides space for electronic components 15 such as for example a charging circuit and/or a security circuit. The charging circuit is necessary in order to provide energy to the battery such that it gets charged properly. It may provide the correct way of charging depending on the charging method that is used (here for example inductive charging). The security circuit may provide electronic components that may be necessary for protecting the device and its user in the case the battery is defect. The battery chassis 12 also provides an electrical contact 16 for electrically connecting the battery and the according circuits with the housing 11 and the rest of the battery powered handheld device 1. In this drawing one electrical contact 16 is shown. The second electrical connection between the battery chassis 12 with the battery 13 and the housing 11 will be described with reference to Figure 4. For mechanically connecting the battery chassis 12 to the housing 11 it provides mechanical fastening means 17 that extend out of the battery chassis 12 into the direction of the housing 11. The fastening means 17 have a shape that enables a snap fit connection with corresponding means arranged in the housing 11 (not shown in the drawings). The fastening means 17 are positioned such that they extend inside of the housing 11 when the battery chassis 12 is connected to the housing 11, such that the outer cylindrical shape of the handheld device 1 is not destroyed by any fastening means.

The battery may be any kind of known energy storing device. It may be a rechargeable built-in battery. It may be a rechargeable standard battery that can be taken out of the battery chassis 12. Or it may be single use standard battery that may get exchanged as soon as it has delivered all the stored energy.

Figure 4 is a partial transparent side view of the handle part 2 of the dental curing light 1 of Figure 1 with the battery chassis 12 being attached to the housing 11. It can be nicely seen that the two parts engage such with each other that the curing light 1 provides a cylindrically shaped handle portion 2. Figure 4 also shows the components inside of the curing light 1. On the side facing the housing 11 the battery chassis 12 comprises electronic components 21 that are only schematically shown in the drawing. On the opposite side the battery chassis 12 comprises, from the right to the left, a charging coil 14, electronic circuits 15 like charging circuit and/or security circuit, an electrical contact connecting the electronic circuits 15 with the battery 13, the battery 13, a further electrical contact 19 connecting the battery 13 with the electronic components 21 of the housing 11 and the electrical contact 16, connecting the electronic circuits 15 of the battery chassis 12 with the electronic components 21 of the housing 12 already described above.

The embodiment described with reference to the Figures 1 to 4 provides the following advantages. The dental battery powered handheld device 1 is light weight and slim in the design such that it enables easy handling. It further provides a closed outer housing 11 and 12 without any electronic contacts being arranged on its outside, which prevents corrosion issues of the contacts. It also provides the possibility of inductively charging the battery 13, which might be useful in some instances. But since the housing can be opened and the battery is accessible, it also provides the possibility of exchanging the battery. The battery can be any kind of battery, such as for example a single use battery or a rechargeable battery. In case of a rechargeable battery the battery may be recharged with any kind of know charging stations (one example will be described with reference to Figure 8) and then replaced.

Figure 5 is an exploded, perspective view of another embodiment of a battery powered dental curing light 1. The curing light 1 of Figure 5 also provides a handle portion 2 and an operating portion 3. Both portions 2 and 3 have a generally circular cross section, wherein the diameter of the cross section of the handle portion 2 is larger than the diameter of the cross section of the operating portion 3.

The operating portion has a general cylindrical shape. At its outermost tip it provides an angled section 4 that carries a light extracting area 5 pointing in a direction approximately perpendicular to the general extension of the battery powered curing light 1. This design ensures that the light, that needs to be projected onto a specific spot in a patients’ mouth can be directed easily onto this spot by holding the battery powered curing light 1 in a hand and directing the operation portion 3 into the mouth of the patient.

The handle portion 2 has also a generally cylindrical shape. It provides an ergonomic shape by having no sharp edges and by having a slightly curved outer surface such that the fingers of a dentist may easily and securely be placed on the handle portion 2. The handle portion 2 further provides a switch 6 for activating and regulating the battery powered handheld device 1. It may also provide an indicating area (not shown in this Figure).

Finally, the dental curing light 1 shown in Figure 5 provides no electrical contacts on its outside. This is a major advantage in the area of battery powered handheld devices, because as already laid out above, there is a risk, especially when the battery powered handheld devices come in contact with liquids, that the electrical contacts corrode, which in the end may lead to a less effective operation of the battery powered handheld device. The battery powered curing light of Figure 5 provides two possibilities for charging, one being an inductive charging and the other being a charging through direct electrical contact. These two options will be described in more details with reference to the following drawings.

Further components of the curing light 1 are a housing 11 and electronic components placed inside of the hosing, indicated at 21. The electronic components 21 will not be explained in detail in this patent application. The curing light 1 also comprises a battery chassis 12 that will be described in more detail with reference to Figures 6 and 7 and a lid 22

Figure 6 is an exploded, transparent view of the handle part 2 of the dental curing light 1 of Figure 5. The curing light 1 provides a housing 11, a battery chassis 12 and a lid 22. Different from the embodiment described above, the battery chassis 12 completely fits into the housing 11. When the lid 22 is attached to the housing 11 the battery chassis 12 and its components are completely placed inside of the housing 11. The interface between the housing 11 and the lid 22 are designed such no water can enter the curing light 1 when the lid 22 is attached to the housing 11. This may be done through the above described means (geometric correlation of the interface and/or additional sealing means).

In the following the battery chassis 12 and its components will be described in more detail with reference to Figures 6 and 7. The battery chassis 12 has the shape of a half- cylinder. It carries from the right to the left a coil 14 for inductive charging, electronic circuits 15 like for example a charging circuit and/or a security circuit, an electrical contact 18 for electrically connecting the electronic circuits 15 with the battery 13, the battery 13, a further electrical contact 19 for electrically connecting the battery 13 with the electronic components 21 of the curing light 1 as well as an electrical contact 16 connecting the electronic circuits 15 of the battery chassis 12 with the electronic components 21 of the housing 11.

The embodiment described with reference to the Figures 5 to 7 provides the following advantages. The dental battery powered handheld device 1 is light weight and slim in the design such that it enables easy handling. It further provides a closed outer housing 11 and 12 without any electrical contacts being arranged on its outside, which prevents corrosion issues of the contacts. It also provides the possibility of inductively charging the battery 13, which might be useful in some instances. But since the housing can be opened and the battery chassis 12 is detachable from the housing 11, it also provides the possibility of either direct charging the battery 13 within the battery chassis 12 or exchanging the battery 13. The battery 13 can be any kind of battery, such as for example a single use battery or a rechargeable battery. In case of a rechargeable battery the battery may be recharged with any kind of known charging stations (one example will be described with reference to Figure 8) and then replaced.

Figure 8 is a perspective view of the battery powered dental curing light 1 of Figures

1 to 4 with a charging station 25. The charging station 25 provides a receiving space 26 for receiving the handle part 2 of the curing light 1. Underneath the receiving space 26 a charging coil 27 is positioned which may interact with a charging coil 14 of the curing light 14 for inductive charging the battery 13 of the handheld device 1. This inductive charging provides a simple and fast solution of charging the battery 13 in times the curing light 1 is not used. The charging station 25 with its receiving space 26 also provides a place to store the curing light 1. If inductive charging is not the right charging method, e.g. if charging needs to be done very quickly, the charging station 25 also provides the possibility to charge the batter 13 with direct charging. Therefore, it provides an additional receiving space 27 on its bottom side which is adapted in its shape and size to the shape and size of the batteries 13 used in the curing light 1. It is possible to keep an extra battery 13 in the receiving space 27 underneath the charging station 25 which can be exchanged with the battery 13 inside of the curing light 13 whenever needed.