Patent Description:
Electrical devices may require sterilization. A current sterilization process is autoclaving, which subjects the electrical device to high temperature and pressure sufficient to kill germs, bacteria and viruses. As such, the electrical devices cannot be powered during the sterilization process. However, it is desirable to count the number of times the electrical device has been sterilized by a thermal event wherein the electrical device is exposed to elevated temperatures, such as an autoclave procedure, so as to determine when maintenance is required.

<CIT> discloses a device, such as a threshold-value counter of sterilization cycles, comprises a latching mechanism with a catch element configured as a freely rotatable gear wheel and a pawl, wherein the pawl can engage between two teeth of the gear wheel. For rotation of the gear wheel, a thermally deflectable actuation means is deflected and bent upwards along a rotation direction at a predetermined threshold value and hereby in a retarded state touches one tooth of the gear wheel and causes the rotation. In a further embodiment, the device comprises in a housing and a linear catch element biased by a tension element. A pawl is engaged in the linear catch element. A thermally deflectable actuation element actuates the pawl. In case of deflection of the actuation means the pawl is lifted upwards releasing the engagement with the linear catch element and the linear catch element is pulled by the tension element into a seated position inside the housing. Due to the linear catch element with a limited number of individual teeth for engaging, the repeated use of this counting device is limited.

<CIT> concerns a display device indicating the number of heatings performed, such as for autoclave sterilization, including a rotatable ratchet wheel with teeth in a housing and a shaft arranged slidable above the ratchet wheel. A spring as a temperature-sensitive mechanical element is arranged around the shaft such, that under increasing temperature the spring expands and therewith moves the shaft into a first direction. Hereby, a ratchet serves as the actuating element of the counter and is fixed with one end to the bottom side of the shaft. By movement of the shaft the other end of the fixed ratchet engages a tooth of the ratchet wheel and rotates the ratchet wheel.

<CIT> describes an apparatus for counting the number of times a temperature cycle occurs with a housing having a cylindrical orifice, in which a rotatable ratchet wheel with a plurality of interior teeth having sloping surfaces and back shoulders is arranged. A bimetallic spiral is arranged in the center of the housing, expands sufficiently at a first temperature and rides over a sloping surface and then snaps behind the shoulder of a tooth of the ratchet wheel. A pawl jams into the shoulder preventing a further clockwise rotation of the wheel ratchet. Only when the spiral is cooled again and is radially retarded, the spiral acts on the tooth shoulder and therefore causes a rotation in the counter-clockwise direction.

As such, it is desirable to have a counting device which can count the number of times an electrical device is sterilized by a thermal event without requiring electrical power during the sterilization process.

The objective of the present invention is to improve the known state of the art.

The problem is solved by a counting unit for counting a number of times an electrical device has been sterilized by exposure to a thermal event according to claim <NUM> and as an alternative solution according to claim <NUM>.

The counting unit comprising: a rotary member configured to rotate about a first axis, the rotary member including a plurality of position indicators fixedly disposed on the rotary member; an actuator configured to engage the rotary member, the actuator is configured to change shape from a first configuration to a second configuration when subjected to a predetermined temperature, wherein in the second configuration, the actuator engages the rotary member so as to rotate the rotary member when the actuator changes shape from the first configuration to the second configuration; and a sensor configured to detect the plurality of position indicators so as to determine a rotation of the rotary member, wherein the actuator is an elongated and/or radially expanded member in the second configuration.

Consequently, a counting unit is provided for use in an electrical device. The counting unit is configured to count a thermal event such as a sterilization procedure including an autoclave cleaning operation when the electrical device is not electrically powered. The counting unit operates without requiring electrical power during the sterilization process.

Furthermore, the problem is solved by a counting unit for counting a number of times an electrical device has been sterilized by exposure to a thermal event, the counting unit comprising: a housing; a plunger disposed within the housing, the plunger including a catch, the plunger moveable from a seated position to an extended position; a biasing member disposed within the housing, the biasing member continuously urging the plunger out of the housing; a heat responsive arm movable between an engaged position when the heat responsive arm is below a predetermined temperature and locks the plunger in the seated position, and a disengaged position where the heat responsive arm reaches the predetermined temperature and disengages from the plunger; a drive electrically powered, the drive operable to move the plunger from the extended position to the seated position; a sensor configured to detect the plunger when the plunger is in the extended position; and a controller configured to detect and count the number of times the drive moves the plunger from the extended position to the seated position.

Hereby, the biasing member is configured to continuously urge the plunger in an extended position and the drive is configured to overcome the force of the biasing member so as to move the plunger in a seated position. The heat responsive arm is movable from an engaged position and a disengaged position, wherein the heat responsive arm is moved to the disengaged position when the heat responsive arm reaches a predetermined temperature, and the heat responsive arm is in the engaged position when the heat responsive arm is below the predetermined temperature. In the engaged position the heat responsive arm locks the plunger in the seated position and in the disengaged position, the heat responsive arm is disengaged with the plunger. As such, when a heating event occurs the plunger is placed in the extended position and moved to the retracted position when the drive is powered.

Therewith, counting devices are provided which count the number of times an electrical device is sterilized by a thermal event, which are linked by the common inventive idea of a heat responsive element, the actuator and the heat responsive arm, changing its respective shape depending on the temperature. The heat response and consequently the changing of the shape affects a retraction or expansion of the actuator and/or the heat responsive arm. Consequently, a spatial dimension of the actuator and/or the heat responsive arm is changed resulting for example in a longitudinal and/or radial expansion of the actuator and/or the heat responsive arm. The thermal event that actuates the actuator and/or the heat responsive arm to change shape from the first configuration to the second configuration is associated with the temperatures generated by an autoclave, such as a temperature above <NUM> degrees Celsius and/or at least <NUM> degrees Celsius.

In a first embodiment of the disclosure, a counting unit for counting a number of times an electrical device has been sterilized by a thermal event is provided. The counting unit includes a rotary member, an actuator and a sensor. The rotary member is configured to rotate about a first axis, the rotary member includes a plurality of position indicators fixedly disposed on the rotary member. The actuator is configured to engage the rotary member. The actuator is further configured to change shape from a first configuration to a second configuration when subjected to a predetermined temperature. In the second configuration, the actuator engages the rotary member so as to rotate the rotary member. The sensor is configured to detect the position indicators so as to determine a rotation of the rotary member.

In one embodiment of the counting unit, the rotary member includes a plurality of teeth and/or ramps. In such an embodiment, the actuator is configured to engage one of the plurality of teeth or ramps in the second configuration so as to rotate the rotary member in a first direction.

In another embodiment of the counting unit, the counting unit further includes a catch. The catch is rotatable about a second axis and configured to engage one of the plurality of teeth so as to prevent the rotary member from rotating in a second direction, the second direction opposite of the first direction.

In another embodiment of the counting unit, the counting unit further includes a biasing member configured to continuously urge the rotary member in the second direction.

According to the invention, the actuator is an elongated and/or radially expanded member in the second configuration.

In yet another embodiment of the counting unit, the actuator is an elongated member having a proximal end and a distal end. The distal end is configured to engage one of the plurality of teeth. In the first configuration a distance between the proximal end and the distal end is a first length and in the second configuration the distance between the proximal end and the distal end is a second length. A distance between the distal end of the first length and the distal end of the second length is greater than a distance from one of the plurality of teeth to an adjacent one of the plurality of teeth.

In one embodiment, the actuator is an elongated member made of a shape memory alloy. The shape memory alloy may be made from one of a copper-aluminum-nickel alloy and a nickel titanium alloy.

In a another embodiment of the disclosure, the actuator is a wound member configured to radially expand when subjected to the predetermined temperature. In such an embodiment, the wound member is made of a bimetallic material.

The position indicators can be associated with each tooth or ramp of the rotary member. Position indicators can comprise binary codes, which are patterned so as to indicate a position associated with a respective tooth or ramp. In one embodiment, the binary codes are patterned in such a manner that the number of metallic traces is different with respect to adjacent binary codes on respective tooth or ramp.

Any sensor configured to detect the presence of an object and/or the position indicators may be adapted for use herein, such as an infrared sensor, a photoelectric cell, a capacitive sensor, and the like. Thus, the sensor is configured to detect a rotation of the rotary member or a presence or absence of a plunger so as to detect a thermal event.

When the electrical device is removed from the autoclave and is subsequently powered, the sensor is powered also and the position indicator can be read. By comparing the reading from this position indicator to a position indicator of a previous unpowered state, it can be determined if the position of the rotary member has changed. Thus, a change in position may be determined by having the position indicators alternating in patterns between each other, e.g. the binary encoding pattern may simply be two different patterns. Consequently, the counting unit is able to count the number of times the electrical device has been sterilized by a thermal event.

In the further aspect of the disclosure, a counting unit includes a housing, a plunger, a heat responsive arm, a drive, a sensor, and a controller. The plunger is disposed within the housing. The plunger includes a catch and is moveable from a seated position to an extended position. The second biasing member is disposed within the housing. The second biasing member continuously urges the plunger out of the housing. The heat responsive arm is movable from an engaged position and a disengaged position, wherein the heat responsive arm is moved to the disengaged position when the heat responsive arm reaches a predetermined temperature, and wherein the heat responsive arm is in the engaged position when the heat responsive arm is below the predetermined temperature. In the engaged position, the heat responsive arm locks the plunger in the seated position. In the disengaged position, the heat responsive arm is disengaged with the plunger. The drive is electrically powered. The drive is operable to move the plunger from the extended position to the seated position. The sensor is configured to detect the plunger when the plunger is in the extended position. The controller is configured to detect and count the number of times the drive moves the plunger from the extended position to the seated position. Hereby, the heat responsive arm is likewise an actuator changing its shape and therewith its dimension depending on a predetermined temperature.

In yet another embodiment of this counting unit, the drive is a coil of wire. The heat responsive arm is formed of a bimetallic material. In another embodiment, the counting unit further includes a power input configured to provide electrical power to the drive so as to move the plunger into the extended position when connected to electric power.

The following description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:.

With reference first to <FIG>, an exemplary depiction of an electrical device <NUM> is provided. The electrical device <NUM> includes a counting unit <NUM> configured to count a thermal event. For illustrative purposes, the electrical device <NUM> will be described in the context of an endoscope.

As used herein, a thermal event means any process in which the electrical device <NUM> is subjected to heat, to include autoclaving. Further, it should be appreciated that the counting unit <NUM> described herein may be applicable to any electrical device <NUM> subject to a thermal event. The electrical device <NUM> includes a housing <NUM> configured to house electric components for performing an intended use. The counting unit <NUM> is disposed within the housing <NUM>. <FIG> shows a generic depiction of the counting unit <NUM>, while <FIG> provide a detailed illustration of the counting unit <NUM>, 10a-c.

With reference now to <FIG>, a depiction of a first embodiment of a counting unit <NUM> is provided. The counting unit <NUM> is configured to count the number of times the electrical device <NUM> has been subjected to a thermal event, such a sterilization within an autoclave.

The counting unit <NUM> includes a rotary member <NUM>, an actuator <NUM> and a first sensor <NUM>. The rotary member <NUM> is a gear having a plurality of teeth <NUM> disposed on the circumference of the rotary member <NUM>. The rotary member <NUM> is rotatable about a fixed pin <NUM> which is fixed to a substrate <NUM> which may be formed within the housing <NUM>. The fixed pin <NUM> defines a first axis of the rotary member <NUM>. The first axis is generally centered with respect to the rotary member <NUM>. Preferably, the rotary member <NUM> is configured to freely rotate in a clockwise and counter-clockwise direction. The rotary member <NUM> is illustratively shown as having ten teeth <NUM>. It should be appreciated that the number of teeth <NUM> depicted is illustrative and not limiting to the scope of the appended claims.

The rotary member <NUM> includes a first surface <NUM> opposite of a second surface <NUM>. The second surface <NUM> faces the substrate <NUM>. Preferably, the first and the second surfaces <NUM>, <NUM> are generally planar. The rotary member <NUM> further includes a plurality of position indicators <NUM> fixedly disposed on the second surface <NUM> of the rotary member <NUM>. A depiction of the position indicators <NUM> is illustratively shown in <FIG> depicts the position indicators <NUM> as binary encoding printed on the second surface <NUM>, wherein the binary codes of the binary encoding may be metallic traces. The rotary member <NUM> is shown as having a position indicator <NUM> associated with each teeth <NUM>. The binary codes are patterned so as to indicate a position associated with a respective tooth <NUM>. In one embodiment, the binary codes are patterned in such a manner that the number of metallic traces is different with respect to adjacent binary codes on respective teeth <NUM>.

With reference again to <FIG>, the first sensor <NUM> is opposite of and faces the second surface <NUM> of the rotary member <NUM>. The first sensor <NUM> is a printed circuit board <NUM> having a microcontroller <NUM> and a plurality of conductive traces <NUM> electrically connected to the microcontroller <NUM> on one end and a contact pad <NUM> on the other. The contact pads <NUM> may be formed of an electrically conductive material configured to complete an electric connection with a corresponding metallic trace or binary encodes of the position indicator <NUM>.

In the depiction shown in <FIG>, the printed circuit board <NUM> includes three conductive traces <NUM> defining an output path 34a for a control signal from the microcontroller <NUM> and three conductive traces <NUM> defining an input path 34b for a position signal. In this case, an electrical connection made between the contact pad <NUM> and the metallic trace of the binary encoded rotary member <NUM> is processed to determine if there is a change in a position of the rotary member <NUM>.

With reference again to <FIG>, an illustrative depiction of the actuator <NUM> is provided. The actuator <NUM> is configured to engage the rotary member <NUM>. In particular, the actuator <NUM> is configured to engage the rotary member <NUM> by changing shape from a first configuration to a second configuration when subjected to a predetermined temperature. In the first configuration, the actuator <NUM> is bent as shown in a solid line in <FIG>. When heated to a predetermined temperature, the actuator <NUM> changes shape to the second configuration, wherein the actuator <NUM> straightens out as shown in dashed lines in <FIG> (also shown in a solid line in <FIG>). As shown in <FIG>, as the actuator <NUM> changes from the first configuration (i.e., bent) to the second configuration (i.e., straight), a distal end of the actuator <NUM> presses the corresponding tooth <NUM> so as to rotate the rotary member <NUM>. In particular, the actuator <NUM> rotates the rotary member <NUM> in a first direction, which is a counter-clockwise direction as indicated by the arrow in <FIG>.

In one embodiment, the counting unit <NUM> may further include a first catch <NUM>. The first catch <NUM> is rotatable about second pin <NUM> which defines a second axis. The second pin <NUM> may be fixed to the substrate <NUM> and is configured to engage one of the plurality of teeth <NUM> so as to prevent the rotary member <NUM> from rotating in a second direction, the second direction is opposite of the first direction. In this case, the second direction is a clockwise direction.

<FIG> depict the actuator <NUM> as being an elongated member having a proximal end 14a and a distal end 14b. The proximal end 14a is fixed to the substrate <NUM>. The distal end 14b is configured to engage one of the plurality of teeth <NUM>. In the first configuration a distance between the proximal end and the distal end is a first length "L1" as indicated in <FIG>. In the second configuration the distance between the proximal end and the distal end is a second length "L2" which is commensurate with the length of the actuator <NUM>. A distance between the distal end of the first length "L1" and the distal end of the second length "L2" is greater than a distance "L3" between adjacent teeth <NUM>. Thus, as the actuator <NUM> changes shape from the first configuration to the second configuration, the degree of rotation is sufficient to rotate rotary member <NUM> wherein the teeth <NUM> advance sufficiently to allow the first catch <NUM> to engaging a preceding tooth <NUM>.

As discussed above, the actuator <NUM> is an elongated member. A proximal end of a main body portion <NUM> of the actuator <NUM> may be fixed to an anchor point <NUM>. It should be appreciated that the actuator <NUM> is formed of a material configured to change shape when subjected to a predetermined temperature. As an example, the actuator <NUM> may be formed of a shape memory alloy. The shape memory alloy may be made from one of a copper-aluminum-nickel alloy and a nickel titanium alloy. Such material may be tuned to change shape when subjected to a predetermined temperature. The process of making such a material with the desired shape changing functions is currently known and used and may be modified for use herein. The actuator <NUM> may be described as having the main body portion <NUM> and a flex portion <NUM>. The flex portion <NUM> is contiguous with the main body portion <NUM> and is illustratively shown as being generally centered within the main body portion <NUM>. However, it should be appreciated that the flex portion <NUM> may be disposed in other regions of the main body <NUM>, such as a distal end or a proximal end of the main body so long as the actuator <NUM> engages the rotary member <NUM> when the actuator <NUM> changes from a first configuration to a second configuration. In the illustrative example of an actuator being an elongated member, the flex portion <NUM> is operable to straighten the main body portion <NUM> when the actuator <NUM> is subjected to the predetermined temperature and concurrently rotating the rotary member <NUM>.

The counting unit <NUM> may further include a first biasing member <NUM>. The first biasing member <NUM> is configured to continuously urge the rotary member <NUM> in the second direction. Thus, the first biasing member <NUM> is configured to cooperate with the first catch <NUM> to retain a corresponding tooth <NUM> in engagement with the first catch <NUM> and keep the rotary member <NUM> from rotating.

In operation, as the electrical device <NUM> is subject to a thermal event such as autoclaving. It should be appreciated that prior to autoclaving, the actuator <NUM> is at room temperature and thus is bent, as shown in solid line in <FIG>. During autoclaving, the actuator <NUM> is subjected to a temperature sufficient to actuate the actuator <NUM> so as to change shape from the first configuration to the second configuration, as shown in <FIG> and in dashed lines in <FIG>. Specifically, the actuator <NUM> straightens out so as to push against a corresponding tooth <NUM> of the rotary member <NUM>. The force of the actuator <NUM> as it straightens out is enough to overcome the opposing force of the first biasing member <NUM> so as to rotate the rotary member <NUM> in the first direction (counter-clockwise).

The actuator <NUM> is formed of a shape memory alloy having a resiliency sufficient to overcome the force of the first biasing member <NUM>. Preferably the actuator <NUM> is bent in the first configuration and is straight in the second configuration wherein the distal end 14b of the actuator <NUM> travels a distance, the difference between "L1" and "L2", which is greater than the distance "L3" between adjacent teeth <NUM>. Simultaneously, the teeth <NUM> engaged with the first catch <NUM> rotates away from the first catch <NUM>, and the first catch <NUM> slides against an angled surface of the preceding tooth <NUM> and passes the preceding tooth <NUM> so as to fall onto the angled surface of the next tooth <NUM>. The first biasing member <NUM> urges the rotary member <NUM> in the second direction, placing the first catch <NUM> into engagement with the preceding tooth <NUM> so as to fix the rotary member <NUM> in position. During this process, the position indicators <NUM> are moved, wherein the preceding position indicator <NUM> is placed into contact with the contact pads <NUM> of the first sensor <NUM>.

When the electrical device <NUM> is removed from the autoclave or allowed to cool down, the actuator <NUM> is returned to the first configuration so as to move into a position to engage a preceding tooth <NUM>. When the electrical device <NUM> is powered, the first sensor <NUM> is powered and the microcontroller <NUM> is able to read the position indicator <NUM> and compare the reading from the position indicator <NUM> of a previous unpowered state to determine if the position of the rotary member <NUM> has changed. This may be accomplished by simply comparing if the position indicator <NUM> value has changed. Thus, a change in position may be determined by having the position indicators <NUM> alternating in patterns between each other. That is, the binary encoding pattern may simply be two different patterns, as opposed to the seven different patterns shown in <FIG>.

The microcontroller <NUM> may be further programmed to associate that change in position with a thermal event and thereby associate the change in position with a thermal event, or a sterilization. Accordingly, the counting unit <NUM> is able to count the number of times the electrical device <NUM> has been sterilized by a thermal event. It should be appreciated that the microcontroller may be disposed within the electrical device <NUM> or may be disposed on a camera control unit (not shown), but the contact pads <NUM> are positioned so as to read the position indicators <NUM>. Thus, the printed circuit board <NUM> may simply include the conductive traces <NUM> which are electrically connected to the microcontroller <NUM> which is disposed in the camera control unit.

With reference now to <FIG>, a second embodiment of a counting unit 10a is provided. As shown, the actuator <NUM> is a wound member configured to radially expand when subjected to the predetermined temperature. In such an embodiment, the wound member is made of a bimetallic material. The proximal end 14a of actuator <NUM> is fixedly disposed to an anchor point <NUM> within the rotary member <NUM>. The anchor point <NUM> is centered within the rotary member <NUM> so as to be generally centered within the rotary member <NUM>. The distal end 14b of the actuator <NUM> includes an engagement member <NUM>. The engagement member <NUM> includes a flat surface for engaging the teeth <NUM>.

The rotary member <NUM> is freely rotatable in a clockwise and counter-clockwise direction. The rotary member <NUM> may be held in a carrier <NUM> which has a circular pocket 52a allowing the rotary member <NUM> to rotate therein. The carrier <NUM> may be integrated into the housing <NUM> of the electrical device <NUM>. As shown in <FIG>, the teeth <NUM> are disposed within a circular opening <NUM> of the rotary member <NUM>, as is the first catch <NUM>, and the rotary member <NUM> is centered within the circular opening <NUM>. The position indicators <NUM> are disposed on the first surface <NUM> of the rotary member <NUM>.

As with the first embodiment, the actuator <NUM> is configured to rotate the rotary member <NUM> when the actuator <NUM> (also referred to as a wound member <NUM>) changes shape from a first configuration to a second configuration. In the first configuration (shown in <FIG>), the wound member <NUM> is contracted, while in the second configuration (shown in <FIG>, wherein <FIG> are not fully dimensional concerning the expansion of the wound member <NUM>), the wound member <NUM> is expanded. The wound member <NUM> radially expands from the first configuration to the second configuration when subjected to a thermal event, such as a sterilization within an autoclave. As the wound member <NUM> expands radially, its overall length is essentially constant, and the distal end 14b of the wound member <NUM> moves further from the center of the wound member <NUM> in a radial direction and engages a tooth <NUM>, rotating the rotary member <NUM> in a clockwise direction.

It should be appreciated that the wound member <NUM> is configured to rotate the rotary member <NUM> a distance greater than a distance between adjacent teeth <NUM>. A first biasing member <NUM> (not shown) may be disposed on the second surface <NUM> of the rotary member <NUM> which is formed on an opposite side of the first surface <NUM> of the rotary member <NUM> which is shown in <FIG>. As with the first embodiment, the first biasing member <NUM> is configured to urge the rotary member <NUM> in a counter-clockwise direction, placing the first catch <NUM> into engagement with a tooth <NUM>. As with the first embodiment, the rotation of the rotary member <NUM> rotates the position indicators <NUM>. The first sensor <NUM> shown in <FIG> may be adapted and modified for use in the second embodiment. As such, the printed circuit board <NUM> is positioned over the first surface <NUM>, and processes a change in position in the same manner as described above. For example, the first sensor <NUM> is placed on top of the first surface <NUM> of the rotary member <NUM> so as to position the contact pads <NUM> above the position indicators <NUM>.

An operation of the counting unit 10a according to the second embodiment is now provided. As the electrical device <NUM> is subject to a thermal event, the distal end 14b including the engagement member <NUM> of the wound member <NUM> expands radially and engages one of the teeth <NUM> of the rotary member <NUM> and rotates the rotary member <NUM> so as to advance the tooth <NUM> a distance greater than the distance between adjacent teeth <NUM>, thus the position indicators <NUM> are also advanced, wherein a preceding position indicator <NUM> is now positioned opposite of the contact pad <NUM> of the first sensor <NUM>.

When the electrical device <NUM> is removed from the autoclave or allowed to cool down, the actuator <NUM> is returned to the first configuration wherein the distal end 14b including the engagement member <NUM> of the wound member <NUM> is spaced apart from the teeth <NUM>, as shown in <FIG>. When the electrical device <NUM> is powered, the first sensor <NUM> is powered and the microcontroller <NUM> is able to read the position indicator <NUM> and compare the reading from the position indicator <NUM> to determine that the position of the rotary member <NUM> has changed. The microcontroller <NUM> may be further programmed to associate that change in position with a thermal event and thereby associate the change in position with a thermal event, or a sterilization. Accordingly, the counting unit 10a is able to count the number of times the electrical device <NUM> has been sterilized by a thermal event.

With reference now to <FIG>, another aspect of the second embodiment of the counting unit 10b is provided. The processing of the position indicators <NUM> and thus the counting of a thermal event is the same as described above; however, the mechanical operation of the actuator <NUM> with respect to the rotary member <NUM> is different.

As shown in <FIG>, the actuator <NUM> is a wound member <NUM>. The wound member <NUM> may be the same as the wound member <NUM> disclosed in <FIG>. Specifically, the wound member <NUM> moves between the first configuration (shown in <FIG>) where the wound member <NUM> is contracted, and the second configuration (shown in <FIG>) where the wound member <NUM> is expanded. The actuator <NUM> is mounted on the first surface <NUM> of the rotary member <NUM>. The rotary member <NUM> includes a plurality of teeth <NUM> disposed on the circumference of the rotary member <NUM>. The rotary member <NUM> further includes a plurality of ramps <NUM> disposed on the first surface <NUM> of the rotary member <NUM>. As shown in <FIG>, the ramps <NUM> have a top surface 56a which is angled and a front surface 56b which is generally orthogonal to the first surface <NUM> of the rotary member <NUM>. The top surface 56a is angled so as to form an obtuse angle "θ" with respect to the first surface <NUM> as indicated in <FIG>. Accordingly, the engagement member <NUM> of the distal end 14b of the actuator <NUM> is configured to push the front surface 56b of a respective ramp <NUM> and slide over the top surface 56a of the ramp <NUM>. In the current illustration, as the actuator <NUM> radially expands due to heat, the distal end 14b of the actuator <NUM> moves in a counter-clockwise direction, thus pushing one of the teeth <NUM> shown in <FIG> to the left as indicated by the solid arrow. As the actuator <NUM> is cooled, the wound member <NUM> retracts and the distal end 14b of the wound member <NUM> may simply slide over the top surface 56a of the ramp <NUM> to the right of the ramp <NUM> that was pushed. Naturally, as the wound member <NUM> retracts, at some point the distal end 14b of the wound member <NUM> is free of all of the ramps <NUM>.

As with the counting unit <NUM>, 10a shown in <FIG>, <FIG>, when the electrical device <NUM> is removed from the autoclave or allowed to cool down, the actuator <NUM> is returned to the first configuration. However, unlike the counting unit 10a in <FIG>, the distal end 14b of the wound member <NUM> is free of and spaced apart from the teeth <NUM> and instead engages ramps <NUM> to rotate the rotary member <NUM>. When the electrical device <NUM> is powered, the first sensor <NUM> is powered and the microcontroller <NUM> is able to read the position indicator <NUM> on the second surface <NUM> and compare the reading from the position indicator <NUM> to determine that the position of the rotary member <NUM> has changed. The microcontroller <NUM> may be further programmed to associate that change in position with a thermal event and thereby associate the change in position with a thermal event, or a sterilization. Accordingly, the counting unit 10b is able to count the number of times the electrical device <NUM> has been sterilized by a thermal event.

It should be appreciated that the thermal event that actuates the actuator <NUM> to change shape from the first configuration to the second configuration is associated with the temperatures generated by an autoclave. Thus, the actuator <NUM> is formed of a material which does not change shape until the material reaches a temperature associated with autoclaving, such as at least <NUM> degrees Celsius. As such, the actuator <NUM> will not be actuated by being merely placed in a hot room or a hot car.

With reference now to <FIG> and <FIG>, a description of an alternative counting unit 10c for use in an electrical device <NUM> is provided. The counting unit 10c includes a second housing <NUM>, a plunger <NUM>, a heat responsive arm <NUM>, a drive <NUM>, a second sensor <NUM>, and a controller <NUM>. The counting unit 10c is configured to count a thermal event.

The second housing <NUM> is illustratively shown as being cylindrical with an open end 58a opposite of a closed end 58b. Preferably, the second housing <NUM> is formed of a durable material configured to withstand an autoclaving process, such as steel. The second housing <NUM> includes an interior void <NUM> for second housing <NUM> components of the counting unit <NUM>.

The plunger <NUM> is slidably disposed within the second housing <NUM>. The plunger <NUM> is a cylindrical member. A portion of the plunger <NUM> is disposed through the open end 58a of the second housing <NUM> and a portion of the plunger <NUM> is disposed within the interior void <NUM> of the second housing <NUM>. The plunger <NUM> is moveable from a seated position to an extended position. <FIG> shows the plunger <NUM> in the extended position and <FIG> shows the plunger <NUM> in the seated position.

The plunger <NUM> includes a second catch <NUM>. The second catch <NUM> is shown as being a notch which is formed by a slanted surface 72a and a back wall 72b so as to form a generally "V" shaped cross-sectional. The back wall 72b extends along a plane extending radially from a center of the plunger <NUM> so as to be flat. The second catch <NUM> is illustratively shown as being disposed adjacent a distal end of the plunger <NUM>; however, it should be appreciated that the second catch <NUM> may be formed adjacent a center of the plunger <NUM> or any area in between.

The counting unit 10c further includes a second biasing member <NUM>. The second biasing member <NUM> is disposed within the second housing <NUM> between the open end 58a and the closed end 58b. One end of the second biasing member <NUM> is fixed in an inner surface of the closed end 58b. The second biasing member <NUM> continuously urges the plunger <NUM> out of the second housing <NUM> and into the extended position. The second biasing member <NUM> is illustratively shown as being a coil spring; however, any biasing member known and used or later developed may be modified for use herein.

The heat responsive arm <NUM> is disposed on an exterior surface of the open end 58a of the second housing <NUM> and is generally parallel to and spaced apart from the plunger <NUM>. The heat responsive arm <NUM> is movable from an engaged position (<FIG>) and a disengaged position (<FIG>). The heat responsive arm <NUM> is configured to move from the engaged to the disengaged position when the heat responsive arm <NUM> reaches a predetermined temperature. The heat responsive arm <NUM> is in the engaged position when the heat responsive arm <NUM> is below the predetermined temperature. The heat responsive arm <NUM> is formed of a material configured to change shape, such material is known and illustratively includes a shape memory alloy such as Nitinol® or may be a bimetallic material wherein each metal has different heat expansion rates.

<FIG> shows the heat responsive arm <NUM> in the disengaged position. In the disengaged position, the heat responsive arm <NUM> is disengaged with the plunger <NUM>. <FIG> shows the heat responsive arm <NUM> in the engaged position. In the engaged position, the heat responsive arm <NUM> locks the plunger <NUM> in the seated position. The heat responsive arm <NUM> may include a tab <NUM> disposed on the distal end of the heat responsive arm <NUM>. The tab <NUM> is configured to engage the second catch <NUM> of the plunger <NUM> so as to prevent the second biasing member <NUM> from urging the plunger <NUM> into the extended position.

The drive <NUM> is disposed within the second housing <NUM> and is electrically powered. The drive <NUM> is operable to move the plunger <NUM> from the extended position to the seated position. In other words, the drive <NUM> is configured to pull the plunger <NUM> into the second housing <NUM>. The drive <NUM> is mechanically configured to generate sufficient pulling force to overcome the force of the second biasing member <NUM>. In one embodiment, the drive <NUM> is a coil of wire that when powered generates an electromagnetic force configured to pull the plunger <NUM> inwardly into the second housing <NUM>. The controller <NUM> is further configured to provide electrical power to the drive <NUM> so as to move the plunger <NUM> into the extended position when connected to electric power. In one embodiment, the controller <NUM> includes a battery which may be electrically coupled to the electrical device <NUM>. In another embodiment, the controller <NUM> is electrically powered by an electrical connection of the electrical device <NUM> to a residential or commercial power plug. For example, the counting device 10c may include a power input <NUM> configured to electrically connect to the power supply of the electrical device, the power input <NUM> may be a pair of wires which pass through the controller <NUM>. In such an embodiment, the controller <NUM> includes known electrical components (not shown) configured to regulate power to the drive <NUM>. Such known electrical components include but are not limited to relays, fuses and the like.

The second sensor <NUM> is configured to detect the plunger <NUM> when the plunger <NUM> is in the extended position. Any sensor configured to detect the presence of an object may be adapted for use herein, illustratively including an infrared sensor, a photoelectric cell, a capacitive sensor, and the like. In such a manner, the second sensor <NUM> may detect the presence of the plunger <NUM> by contact or by proximity. For illustrative purposes, the second sensor <NUM> is shown displaced from the distal end of the plunger <NUM> when the plunger <NUM> is in the extended position. However, it may be the case that the second sensor <NUM> is a capacitive sensor which is configured to contact the plunger <NUM> to determine that the plunger <NUM> is in the extended position. As such, the depiction shown in <FIG> is illustrative and not limiting to the scope of the appended claims.

The controller <NUM> is configured to detect the position of the plunger <NUM> and count the number of times the drive <NUM> moves the plunger <NUM> from the extended position to the seated position. The number of times the plunger <NUM> moves from the extended to the seated position may be associated with a thermal event so as to track the number of times the electrical device <NUM> has been sterilized by a thermal event. The controller <NUM> may be a microcontroller mounted onto a printed circuit board <NUM> which includes electrical components configured to count the number of times the electrical device <NUM> has been sterilized by a thermal event. As described above, this may be done by associating a thermal event with a sterilization. The controller <NUM> may determine a thermal event by counting the number of times the plunger <NUM> is detected in the extended position or by the number of times the drive <NUM> draws the plunger <NUM> from the extended position to the seated position.

In operation, the counting unit 10c is disposed within the electrical device <NUM> wherein the plunger <NUM> is in the seated position, as shown in <FIG>. When the user sterilizes electrical device <NUM>, using an autoclave as an example, the heat responsive arm <NUM> is moved from engaged position to the disengaged position when the heat responsive arm <NUM> reaches a predetermined temperature. It should be noted that the predetermined temperature need not be the operating temperature of the autoclave, but may be set to be lower. For instance, the predetermined temperature may be <NUM> degrees Celsius.

As the heat responsive arm <NUM> moves from the engaged position to the disengaged position, the tab <NUM> clears the second catch <NUM> allowing the second biasing member <NUM> to urge the plunger <NUM> from the seated position to the extended position. The plunger <NUM> remains in the extended position during the duration of the sterilization process. When removed from the autoclave, the electrical device <NUM> is allowed to cool wherein the heat responsive arm <NUM> returns to the engaged position. However, the plunger <NUM> is still in the extended position and thus the tab <NUM> of the heat responsive arm <NUM> is not engaged with the second catch <NUM> but just behind the catch, e.g. disposed between the second catch <NUM> and the open end 58a of the second housing <NUM>.

When the electrical device <NUM> is powered, the second sensor <NUM> is able to detect that the plunger <NUM> is in the extended position, wherein the controller <NUM> processes the position of the plunger <NUM> and powers the drive <NUM> so as to move the plunger <NUM> into the seated position. The drive <NUM> draws the plunger <NUM> into the second housing <NUM>, overcoming the biasing force of the second biasing member <NUM> so as to move the second catch <NUM> past the tab <NUM>, wherein the tab <NUM> is free to engage the second catch <NUM>. The controller <NUM> may be configured to turn off the drive <NUM> when the plunger <NUM> is in the seated position. In one embodiment, the controller <NUM> is configured to actuate the drive <NUM> for a predetermined period of time before turning off the drive <NUM>. In such an embodiment, the predetermined period of time is sufficient to draw the plunger <NUM> into the seated position. In another embodiment, a third sensor (not shown) may be positioned within the second housing <NUM> to detect when the plunger <NUM> is in the seated position. In either case, when the drive <NUM> is turned off, the second biasing member <NUM> is free to urge the plunger <NUM> from the seated position to the extended position. However, the tab <NUM> of the heat responsive arm <NUM> engages the second catch <NUM> of the plunger <NUM> so as to retain the plunger <NUM> in the seated position.

As described above, the controller <NUM> is configured to count and track the number of sterilizations performed by a thermal event. In one embodiment, the determination of a sterilization is made by a thermal event, which may be associated with the detection of the plunger <NUM> in the extended position, or the actuation of the drive <NUM>.

It should be appreciated that the thermal event that actuates the heat responsive arm <NUM> to move from the engaged to the disengaged position is associated with the temperatures generated by an autoclave. Thus, the heat responsive arm <NUM> is formed of a material which does not change shape until the material reaches a temperature associated with autoclaving, such as at least <NUM> degrees Celsius. As such, the heat responsive arm <NUM> will not be actuated by being merely placed in a hot room or a hot car.

Claim 1:
Counting unit (<NUM>, 10a, 10b) for counting a number of times an electrical device (<NUM>) has been sterilized by exposure to a thermal event, the counting unit (<NUM>, 10a, 10b) comprising:
a rotary member (<NUM>) configured to rotate about a first axis (<NUM>), the rotary member (<NUM>) including a plurality of position indicators (<NUM>) fixedly disposed on the rotary member (<NUM>);
an actuator (<NUM>) configured to engage the rotary member (<NUM>), the actuator (<NUM>) configured to change shape from a first configuration to a second configuration when subjected to a predetermined temperature; and
a sensor (<NUM>) configured to detect the plurality of position indicators (<NUM>) so as to determine a rotation of the rotary member (<NUM>), characterized in
the actuator is an elongated and/or radially expanded member in the second configuration, wherein the actuator (<NUM>) engages the rotary member (<NUM>) so as to rotate the rotary member (<NUM>) when the actuator (<NUM>) changes shape from the first configuration to the second configuration.