MXPA99007577A - Apparatus preventing electric shock, for use with a component that has a non-isolated outer surface - Google Patents

Abstract

The present invention relates to a finger protector, which is used with an electronic device, to restrict physical access to a component of this electronic device, which has an uninsulated surface, adapted to carry a voltage. The apparatus includes a housing, which defines a first opening and which is adapted to mount the electronic device, so that this first opening allows passage of the passive infrared energy and ambient light to the component. The apparatus also includes an arrangement of projections, which extends from the housing, which limits physical access to the surface of the component through the first opening and which defines a second opening, through which infrared energy can enter. and go through the first opening to the component. An electronic circuit may also be provided, which limits the current provided to an uninsulated component, such as an infrared or environmental light detector of the electronic device, from a circuit of the electronic device. The apparatus includes a resistive element, which couples a terminal of the component without insulating ground, and a capacitive element, which also couples the terminal of the uninsulated component to ground. The resistive and capacitive elements have resistance and capacitance values, respectively, that limit the current to less than 500

Description

APPARATUS PREVENTING ELECTRICAL SHOCK. FOR USE WITH A COMPONENT THAT HAS A SURFACE EXTERIOR NOT ISOLATED BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an apparatus and method for preventing electrical shock, due to contact with an uninsulated electronic component, such as a passive infrared detector. More particularly, the present invention relates to a mechanical apparatus, such as a finger guard, which restricts physical contact with an uninsulated component, for example an infrared detector, which carries a voltage, and an electrical device, such as a current limiting circuit, which limits the current supplied to an uninsulated component, to prevent electric shocks due to inadvertent or intentional contact with this non-isolated electrical component. Description of the Related Art; A switch of a motion sensor, such as the Model AT277W switch, manufactured by Hubbell, Inc., includes a passive infrared detector (PIR), and an ambient light detector. This motion sensor switch can be used, for example, as a busy state detector, which turns off the lights after a period of time in a room, when no one is present in this room, and turns on the lights in the room when a person enters the same. The motion sensor switch can also be used, for example, as a motion sensor for an alarm system. The motion sensor detects movement in a busy area, such as an office, a conference room in a building, or a home, and in turn controls lighting loads to save energy. The motion sensor detects a change in the radiated infrared energy of the occupant, as this occupant moves in and out of, or between the PIR lenses, which detect the compartments. This PIR detector has a pass band in the infrared range of 8 to 14 μm. If a person enters the monitored area, this person changes the amount of infrared energy that is detected by the PIR detector. Therefore, the magnitude of the signal output by the PIR detector, which is representative of the amount of infrared energy detected, will change. The detection circuit in the motion detector device processes this signal and produces a signal indicating the amount of infrared energy that has changed received by the infrared detector.

The control circuit interprets the output of the signal by the IR detection circuit, together with the signal provided by the ambient light detector. If the signal provided by the ambient light detector indicates that this ambient light, in the monitored area, is low (for example, a very unnatural light is present in the monitored area), the control circuit will turn on or increase the brightness of the the lights in the monitored area. However, if the signal provided by the ambient light detector indicates that this ambient light in the monitored area is sufficient (for example, due to sunlight, etc.), the control circuit can not turn on or do more Bright lights, or you can just make the lights brighter in a slight way. In any case, the control of the lights is based on the signals provided by the infrared detector and the ambient light detector. If a person (occupant) then leaves the monitored area for a period of time that exceeds the "off delay" time, the motion sensor circuit shuts off the lighting load in the monitored area. The infrared detector and the ambient light detector employed in a motion detector switch, of the type described above, are non-insulated electronic components, which, during operation typically carry voltage in at least a portion of their outer casing, or in exposed non-isolated terminals. Because these voltages can create a danger of an electrical shock, the UL standards covering non-insulated active parts (ie UL733A, effective August 30, 1998), require that either the physical access to the infrared detector and the ambient light detector be restricted, or that the current provided The infrared detector and the ambient light detector shall be limited to less than 500 μA. Therefore, in a motion sensor switch, of the type described above, a Fresnel lens, which is made of, for example, polyethylene, flexible plastic or other suitable material, is installed in front of the infrared detector and the detector of the environmental light This lens is more transmitting in the infrared range of 8-14 μm, but it also allows visible ambient light (400 to 700 nm wavelength) to pass. This makes it possible for the infrared detector and the ambient light detector to receive infrared energy and ambient light, respectively, while also preventing physical contact with the infrared detector and the ambient light detector. Although a lens, of the type described above, is typically suitable for preventing contact with the infrared detector in the motion detector switch while in place, the violation (e.g., cutting or forcing with a tool) of the switch of the Motion detector, can result in lens removal. Once the lens has been removed, the surfaces of the infrared detector and the ambient light detector are exposed and can make contact, for example, with a person's finger, which may result in the person receiving an electrical shock from the person. voltage and current carried by those detectors. Also, the lens is made of a material which will usually melt when exposed to fire. Therefore, due to the required infrared transmission properties, the lens is not capable of passing a 12.7 cm flame test, required in UL773A. Although it is possible to supply a flame resistant lens over the infrared energy and ambient light detectors, these types of lenses can be very expensive and thus do not provide an effective cost solution. Accordingly, there continues to be a need for an apparatus and method which provides added security in preventing an electrical shock due to contact with infrared and ambient light detectors, for example, a motion detector switch, which does not obstruct Significantly the passage of infrared energy and ambient light to the infrared and ambient light detectors, respectively, and which also complies with the UL773A standard.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus which restricts physical access to an uninsulated component, such as an infrared light detector or ambient light, in a device, such as a motion detection device, for Prevent electrical shock due to the voltage and current carried by the uninsulated component, and which completely complies with the normal UL773A. Another object of the present invention is to provide an apparatus which restricts physical contact with an uninsulated component, such as an infrared or environmental light detector, in a device, such as a motion sensing device, while allowing a sufficient amount of infrared energy and light is received by the non-isolated component, for the attempted operation of this non-isolated component. A further object of the present invention is to provide an apparatus, such as an electronic circuit, which limits the amount of the current provided to an uninsulated component, such as an infrared or ambient light detector, in a device, such as a movement detection device, for the safe protection against electric shock to a person making contact with the non-isolated component, while making it possible for this non-isolated component to operate as intended.

These and other objects of the present invention are essentially obtained by the provision of an apparatus, such as a finger guard, for use with an electronic device, to restrict physical access to a component of the electronic device having an adapted surface. to carry a voltage. This apparatus includes a housing, which defines a first opening, and which is adapted to be mounted to the electronic device, so that this first opening allows the passage of light to the component. The apparatus further includes a projection arrangement, which extends from the housing and which defines a second opening, which allows infrared energy and light to pass through it, to go through the first opening to the component, while it also limits physical access to the surface of the component through the first opening. The projection arrangement may include a plurality of projections, which are arranged at intervals around the first aperture, and each includes a first projection portion which extends away from the housing, and a second projection portion, which is extends transversely of the direction of extension of the first projection portion. The edges of the second projection portion of each projection fall substantially within a periphery, which defines the second aperture. The above objects, together with other objects, are also essentially achieved by the provision of an apparatus for use with an electronic device, to limit the current provided to an uninsulated component, such as an infrared detector of the electronic device, from a circuit of this electronic device. The apparatus includes a resistive element, which couples the terminal of the uninsulated component to ground, and a capacitive element, which also couples the terminal of the uninsulated component to ground. The resistive and capacitive elements have resistance and capacitance values, respectively, which limit the current to less than about 500 μA. The capacitive element comprises a plurality of capacitors, which are coupled in series. Therefore, if one of the capacitors becomes shorted, the rest of the capacitor (s) will provide sufficient capacitance to enable the apparatus to limit the current supplied to the non-isolated component to less than about 500 μA. Other objects, advantages and salient features of the invention will become more apparent from the following detailed description, which taken in conjunction with the accompanying drawings, exhibits the preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the accompanying drawings, which form part of the original description: Figure 1 is a perspective view, with separate parts, of a motion sensing device, employing a finger guard, in accordance with one embodiment of the present invention; Figure 2 is an enlarged front view of the motion detector device, shown in Figure 1, with the lens being removed to expose the finger guard; Figure 3 is an enlarged perspective view of the finger guard, shown in Figures 1 and 2; Figure 4 is a front view of the finger guard, shown in Figures 1-3; Figure 5 is a cross-sectional view of the finger guard, taken along lines 5-5 in Figure 4; Figure 6 is a cross-sectional view of the finger guard, taken along lines 6-6 of Figure 4; Figure 7 is a cross-sectional view of the finger guard, taken along lines 7-7 of Figure 4; Figure 8 is a top view of the finger protector, shown in Figure 4; Figure 9 is an enlarged detail view of the opening and projections of the finger guard, shown in Figure 4; Figure 10 is a schematic front view of an articulated probe, in accordance with the UL guide lines, UL773A, which is used to determine whether the finger guard, shown in Figure 4, sufficiently limits access to the infrared detector and to the ambient light detector of the motion sensor device, shown in Figures 1 and 2; Figure 11 is a side view of the probe shown in Figure 10; Figure 12 is a plan view of the proximal end of the probe, taken in the direction of lines 12-12 in Figure 10; Figure 13 is a cross-sectional view of the probe, taken along lines 13-13 in Figure 10; Figure 14 shows a cross-sectional view of the finger guard shown in Figures 3 to 9, in relation to the distal end of the articulated probe, shown in Figures 10 to 13; Figure 15 is a perspective view of a finger guard, according to another embodiment of the present invention; Figure 16 is a top plan view of the finger guard shown in Figure 15; Figure 17 is a top plan view of a finger guard, according to a further embodiment of the present invention; and Figure 18 is a schematic electronic view of a circuit, according to an embodiment of the present invention, for limiting the current, which is supplied to an infrared detector in the motion detector device shown in Figures 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES A motion detector 100, in which a finger guard, according to one embodiment of the present invention is employed, is illustrated in Figures 1 and 2. This motion detector 100 may be, for example, example, the AT277W motion detector switch, manufactured by Hubbell, Inc., or any other suitable motion detector.

The motion detector 100 includes a front housing 102 and a rear housing 104, which are made of plastic, a composite material or any other suitable material, and are internally locked together to form the housing of the motion detector 100. Specifically, the front housing 102 includes the latch members on its top and bottom, which receive the locking tongues 108 on top and bottom of the rear housing 104, to latch, releasably, the front and rear housings , 102 and 104, with each other. The motion detector 100 further includes a circuitry, comprising a circuit board 110 for power supply, having a wire 112 coupled, which is connected to an alternating current power source (not shown), to supply energy to circuit 110 that supplies power. This circuit board 110 for power supply also has a wire 113 coupled, which is used to supply an output of the motion detector 100 to, for example, control a lighting circuit. The motion detector 100 further includes a printed circuit board assembly 314, which includes components, such as a light emitting diode (LED) 116, indicating motion, an infrared detector 118, and a light detector 119 environmental, whose purpose will be described in detail below. The circuit board assembly 114 further includes the connectors 120, which are plugged into the PCB 122 of the power supply circuit board 110 to enable the circuit board assembly 114 to receive power from the supply circuit board 110 of energy. An isolator 124 is placed between the power supply circuit 110 and the circuit board assembly 114, to prevent unintentional contact between the components in the circuit board 110 of the power supply and the assembly 114 of the circuit board. The motion detector 100 also includes a light tube 126, which is placed over the LED 116, to direct light from the LED 116 through an aperture 128 in the front housing 102. A button 130 is placed in the front. of the front housing 102 and mechanically connected to bypass the oppressor button 132 in the assembly 114 of the circuit board. The front housing 102 further includes a switch opening 134, which provides access to an automatic / off switch 136 in the circuit board assembly 114. A door 138 is removably attached to the front housing 102 to cover the paid / automatic switch 136 and thus allows access to this switch 136 only when it is removed.

The front housing 102 also includes a window 140, which allows the passage of infrared energy and light to the infrared detector 118 and the ambient light detector 119, as described in more detail below. A lens 142, which is made, for example, of a flexible plastic material and is essentially transparent to infrared energy and can be used for ambient visible light, is mounted on the window 140. When the lens 142 is mounted on the the window 140, this lens 142 prevents physical access to the components, such as the infrared detector 118 and the ambient light detector 119, on the assembly 114 of the circuit board. The lens 142 includes the tabs 143, the purpose of which is described below. The motion detector 110 may also include a tag 144, which is attached to the wires 112 and 113, for example, and includes the information pertaining to the wire joint. This motion detector 110 may further include a tag 146, which attaches external portions of the front and rear housings, 102 and 104, and includes information, such as the part number, UL rating criteria, and the like. The motion detector 100 also includes a support assembly 148, which has openings 150, which receive the locking tabs 108 of the rear housing 104 and the latch members 106 of the front housing 102, to mount the support assembly 148 to the housing, front and rear, 102 and 104, assembled. The support assembly 148 further includes a ground wire 151, which can be coupled to ground or, for example, to a ground terminal of the power supply (not shown), which provides power to board 110 of the power supply circuit. energy, as described before. A metal plug assembly 152 is mounted to the support assembly 148 by a screw 154, which shaft passes through the opening 156 in the support assembly 148 and into the opening 158 in the pin assembly 152. This pin assembly 152 passes through the opening 160 in the rear housing 104 and engages a slot (not shown) in the power supply circuit board 110, to provide an electrical connection between the circuit board 110 power supply and wire 151 to ground. The support assembly 148 further includes the screws 162 which pass through the openings 164 in the support assembly 148, to mount this support assembly and thus, the motion detector 100, in an electrical box, for example. The washers 166 can be used in conjunction with the screws 162 to mount the bracket to the electrical box. This support assembly 148 also includes additional openings 168, which can receive additional screws, rivets or other suitable structure for the motion detector 100 on the support surface. As described above, a finger protector 170, according to one embodiment of the present invention, is employed in the motion detector 100, as shown. This finger protector 170 is a one-piece integral unit, made, for example, of a hard or relatively hard plastic or composite material, or any other suitable material, as per the UL773A standards, mentioned above. The finger protector 170 may also include warning labels 172, which provide information relating to a potential hazard, created by the infrared detector 118 and the ambient light detector 119, as described in more detail below. As shown in Figure 2, in particular, the finger protector 170 is positioned between the circuit board assembly 114 and the front housing 102, so the finger protector 170 is aligned with or essentially aligned with the window 140 in the front housing 102. When the lens 142 is mounted in the window 140, this lens 142 covers the front of the finger protector 170. However, for illustrative purposes, Figure 2 shows the motion detector 100 with the lens 142 being removed to expose the finger protector 170.

As further shown in Figure 2 and described in more detail below, the finger protector 170 includes a circular or substantially circular opening 174, which is aligned with the infrared detector 118, when the finger protector 170 is mounted on a 100 movement detector. This finger protector 170 also includes an aperture 175 of substantially rectangular configuration, which is aligned with the ambient light detector 119, when the finger protector 170 is mounted on the motion detector 100. Thus, as described in more detail below, the infrared energy and ambient light entering the window 140 of the front housing 102 passes through the openings 174 and 175 in the finger protector 170 and is detected by the infrared detector 118. and the detector 119 of ambient light, respectively. The finger protector 170 is shown in greater detail in Figures 3-9. This finger protector 170 includes a vertical wall portion 176, an upper wall portion 178 and a bottom wall portion 180, which are integral with each other. The vertical wall portion 176 has portions, 182 and 183, flat or substantially flat, inclined portions, 184 and 186, and a flat or substantially planar portion, 188, extending parallel or substantially parallel to the flat portions 182 and 183 The flat portions, 182 and 183, each have a TI thickness of about 0.635 mm. The inclined portions 184 and 186 each extend at an angle? 1 with respect to their respective planar portion, 182 and 183, and each has a width DI measured from a central vertical plane Y, which, as shown in FIG. Figure 5, extends through the center of the finger protector 170. In this example, it is approximately 20o- and the width W is approximately 8128 mm. The combined width W2 of the inclined portions 184 and 186, in this example, is therefore about 16,256 mm. The recessed flat portion 188 is divided by the vertical plane Y into two halves, which have essentially equal widths, with the general width 3 of the recessed flat portion 188, in this example, being about 10.16 mm. The back surface of the recessed flat portion 188 is recessed at a distance DI from the back surfaces of the planar portions 182 and 183. In this example, the distance DI is about 1.1176 mm. An elevated portion 189 extends outwardly from the inclined portions 184 and 186 and the recessed flat portion 188. The raised portion 189 includes a circular or substantially circular portion, which surrounds the opening 174 in the finger protector 170, and a portion 191 of substantially rectangular configuration, which encircles the second opening 175 in a finger protector 170. In this example, the circular portion has a diameter of about 13,462 mm and the opening has a diameter of about 10.16 mm, which is sufficient to accommodate the infrared detector 118, so nothing of the circular portion 190 obstructs the front surface of the detector. infrared detector 118. The circular portion 190, therefore, has a thickness of approximately 3,302 mm. Also in this example, opening 175 has a length Ll of about 0.5,461 mm, with each longitudinal edge of portion 191 of rectangular configuration having about 52 of draft (see Figure 9, in particular), and has a Hl height of about 4064 mm with each height edge of the rectangular configuration portion 191 having about 52 shot. In this example, portion 191 of rectangular configuration has a thickness of about 0.762 mm, with each of the four slivers of portion 191 of rectangular configuration being surrounded to have an internal radius of about 0.762 mm. The finger protector 170 further includes projection portions 192, 194, 196 and 198, each of which extends outwardly from the raised portion 190 at a distance D2 from the rear surface of the recessed flat portion 188., a distance D3 from the back surfaces of the flat portions 182 and 183 and an angle of about 22 with respect to the vertical plane Y. In this example, the distance D2 is around 5,461 mm and the distance D3 is around 4,343. mm. Additional details of the projection portions 192, 194, 196 and 198 and their purpose are described below. The vertical wall portion 170 further includes vertical edge portions 200 and 202, which extend outward from the opposite side edges of the flat portions 182 and 183, respectively, in a normal or substantially normal direction to the planar portions 182 and 183. at a distance D4 from the back surface of the flat portions 182 and 183, respectively. In this example, the distance D4 is around 2286 mm. The width 4 of the finger protector 170 taken between the inner surfaces of the vertical edge portions 200 and 202 is about 26,162 mm in this example. The vertical edge portion 202 includes a notch 204, having a depth D5 and a length L2, which functions as a locating notch to position the finger protector 170 correctly with respect to the lens 142 of the motion detector 100. In this example, the depth D5 is around 1143 mm and the length L2 is around 0.508 mm. As shown in Figure 1, the notch 204 receives the tab 143 of the lens 142 and does maintain the finger protector 170 in a predetermined position with respect to the lens 142.

The upper portion 187 of the finger proor 170 includes a lower or substantially planar flat portion 206, and an upper or substantially planar flat portion 208, which is parallel or substantially parallel to the lower planar portion 206. The upper portion 178 further includes a stepped edge portion 212 including an outer edge surface 214, a step surface 216 and an inner edge surface 218. The stepped edge portion 212 receives a flange (not shown) along the upper inner surface of the lens 142 to assist in securing the finger proor 170 to the lens 142, during assembly. The outer rim surface, 214, extends normal or substantially normal to the lower planar portion 205 and is integral with the stepped surface 216, which extends normal or substantially normal to the outer rim surface, 214, and thus parallel or substantially parallel to the lower flat portion 206 and the upper flat portion 208. The inner edge surface 218 extends between an edge of the upper planar portion 208 and an edge of the stepped surface 216, normal or substantially normal to the stepped surface 216 and the upper flat portion 208. In this example, the outer edge surface 214 extends over a height H2 which, in this example is about 0.762 mm, and the inner edge surface 218 extends over a height H3 which, in this example is around 0.762 mm. Therefore, the overall height H4 between the lower flat portion 206 and the upper flat portion 208 is about 1524 mm, in this example.

Also, as shown in Figure 8, in particular, the outer edge surface 214 extends arcuately at a radius R1 which, in this example, is approximately 14,351 mm and the inner edge surface 218 arches in an arcuate manner. radius R2 which, in this example, is about 13,487 mm. Therefore, the lower planar portion 206 and the upper planar portion 208 each have a semicircular or substantially semicircular configuration. However, as further shown in Figure 8, the outer edge surface 214 includes straight or substantially straight portions, 220 and 222, and an inner edge surface 218, which includes straight or substantially straight portions, 224 and 226. straight portions, 220-226 each extend normal or substantially normal to vertical wall portion 176 at a distance D6 from the back surface of the flat portions, 182 and 183. In this example, D6 is about 3030 mm. Therefore, the finger proor 170 has a general width W5 of about 27,432 mm in this example, as measured between the outer surfaces of the straight portions, 220 and 222. The width 6, measured between the internal surfaces of Straight portions, 220 and 222, is around 25,654 mm in this example. The upper portion 178 also includes projections 228 and 230, each extending from the upper planar portion 208 in a normal or substantially normal direction to the upper planar portion 208 at a height H5, which is 0.762 mm in this example. The projection 228 has a beveled end 232 and the projection 230 has another beveled end 234. The bevelled ends 232 and 2234 each extend at an angle of 302 with respect to the upper planar portion 208 and thus, at an angle of about 30s with respect to the upper surfaces of the projections 228 and 230. These projections, 228 and 230, each extend rearwardly along the upper planar portion 208 from the inner edge surface 218 at a distance D7 from the rear surface. of the respective flat portions 182 and 183. In this example, the distance D7 is approximately 6.35 mm. The projections 228 and 230 each have a width W7 which, in this example, is about 1.27 mm. The external sides of the projections, 228 and 230, each one extends at an angle? 2 of about 52, with reference to the respective planes, which are parallel to the vertical plane Y. The centers of the projections 228 and 230 are spaced at a width of 8, which, in this example, is about 19.05 mm and are thus at a distance W9 of about 9.525 mm from the vertical plane Y. The upper portion 178 further includes an inclined portion 236, which extends at an angle 03 with with respect to the upper flat portion 208. In this example, 3 3 at an angle of approximately 26 °. The vertical sections 238 and 240 extend downward in a normal or substantially normal direction to the lower flat portion 206 to the inclined portion 236, as shown. As further illustrated, the label 172 is attached to the inner surface of the inclined portion 236. This inclined portion 236 has a width W10 which, in this example, is about 9,982 mm and extends from the back surfaces of the portions flat, 182 and 183, for a distance D8 which, in this example, is about 10.16 mm, taken along the vertical plane Y. As shown further, the width ll of the rear surface of the flat portion recessed 188 is about 11.43 mm in this example, which is slightly larger than the width 10 of the slanted portion 236. The bottom portion 180 includes a lower flat portion 242 and an upper planar portion 244, which extends parallel or substantially parallel to the lower flat portion 242. The bottom portion 180 further includes a stepped edge portion 246 that includes an inner edge surface 248, a stepped surface 250 and an outer edge surface 252. The portion of Stepped edge 246 receives a flange (not shown) extending along the internal bottom surface of lens 142 to assist in securing finger guard 170 to lens 142 during assembly. The inner edge surface 248 extends upwardly from the lower flat portion 242, in a direction normal or substantially normal to the lower planar portion 242. The stepped surface 250 extends from the inner edge surface 248 in a normal or substantial direction normal to the inner edge surface 248, and the outer edge surface 252 extends between the stepped surface 250 and the upper planar portion 244 and curves in a radius of about 0.508 mm. The inner edge surface 248 extends arcuately at the radius R2 described above, while the outer edge surface 252 extends arcuately at the radius R1, described above. In this example, the finger protector 170 also has the following dimensions. The height H6 of the finger protector 170, taken between the lower flat portion 242 and the upper flat portion 208, in this example, is approximately 27.7368 ram. The height H7, taken between the upper flat portion 244 and the lower flat portion 206, in this example, is approximately 24.8158 mm. The height H8, taken between the lower flat portion 242 and the lower edge of the inclined portion 236, in this example, is about 20,828 mm. This height H8 is also essentially equal to the height of the inclined portion 184 and 186, taken from the lower flat portion 242. The height H9, taken from the lower flat portion 242 to the bottom edge of the second opening 175, in this example , it is around 2.7432 mm and the height H10, taken from the bottom edge of the second opening 175 to the horizontal plane X, passing through the center of the opening 174, is around 10.2362 mm in this example. The height Hll, between the lower flat portion 242 and the bottom edge of the indentation 204, in this example, is about 11,176 mm. The height H12 between the stepped surface 250 and the stepped surface 217 in this example is about 26,162 mm. Details of the projection portions 192 will now be described., 194, 196 and 198. As shown explicitly in Figures 7 and 9, the projection portion 192 includes a first portion 154 and a second portion 256. As discussed above, the projection portion 192 extends at an angle of shot of about 22 with respect to the vertical plane Y. Thus, the first portion 254 extends outwardly from the raised portion 190 at that angle of shot and thus substantially normal to the upper surface of the raised portion 190. The projection portion 194 it includes a first portion 258 and a second portion 260, which are similar or identical in size and construction to the first and second portions, 254 and 256, respectively. The projection portion 196 includes a first portion 262 and a second portion 264 that are similar in size and construction to the first portion 254 and the second portion 256, respectively. The projection portion 198 includes a first portion 266 and a second portion 268, which are similar in size and construction to the first portion 254 and the second portion 256. Each first portion 254, 258, 262 and 266 has a thickness T2 of about 0.7874 mm and each second portion 256, 260, 264 and 268 has a thickness T3 of about 0.762 mm. As shown in Figure 9, the second portions 256, 260, 264 and 268 e extend radially from the inner edges 270, 272, 274 and 276, respectively, to the outer edges 278, 280, 282 and 284, respectively, of so that the sides 290 and 292 of the second portion 260 extend at an angle T4 to each other, the sides 294 and 296 of the second portion 264 extend at an angle 4 4 to each other, and the sides 298 and 300 of the second. portion 268 e extend at an angle 04 to each other, as shown. In this example,? 4 has a value of about 152. The inner edges 270, 272, 274 and 276 each are placed on or substantially on the perimeter of a circle, defined by the inner edges 270, 272, 274 and 276, which, in this example, has a diameter of about 6,477 mm and is placed within a plane parallel or substantially parallel to a plane in which the aperture 174. is formed. The thickness of each second portion 256, 260, 264 and 268, taken along their respective internal edges 270, 272, 274 and 276, is approximately 0.8636 mm in this example. As shown further in this example, the centers of the second portions 256, 260, 264 and 268 are each at an angle 05 with respect to the horizontal plane H. In this example,? 5 is about 452. Also, sides adjacent portions of the second adjacent portions are at an angle 06 relative to each other, which, in this example, is about 752. It will be noted that, although specific dimensions, angles and radii have been previously discussed for the finger protector 170, the components of the finger protector 170, discussed above, can have any suitable dimension, angle and radius, which achieve the purpose of the finger protector 170, discussed above.

Specifically, as explained above, the finger protector 170 functions to allow infrared energy to be received by the infrared detector 118 and to allow ambient light to be received by the ambient light detector 119, while restricting physical contact with the detector. 118 infrared and 119 detector of ambient light. In particular, the positions and dimensions of the projection portions 192-198 are such that portions of projections 192-198 prevent, for example, the fingers of a person from making contact with the infrared detector 118, while allowing an adequate amount of infrared energy passes through the aperture 174, which is to be detected by the infrared detector 118, so the sensitivity of the motion sensor 100 does not decrease significantly. Similarly, the rectangular portion 191 of the finger guard 170, surrounding the ambient light detector 119, prevents, for example, a person's finger from making contact with the ambient light detector 119, while allowing a Sufficient amount of ambient light passes through the opening 175 to be detected by the ambient light detector 119, so the sensitivity of the motion sensor 100 does not decrease significantly. As explained above, the finger protector 170, and in particular, the projection portions 192-198 and the portion 191 of rectangular configuration, have dimensions that restrict physical contact with the infrared detector 118 and the ambient light detector 119, to the degree necessary to comply with UL773A standards, discussed above. The finger protector 170, therefore, must prevent an articulated probe having dimensions according to UL773A Figure 4.1 from contact with the infrared detector 118 and the ambient light detector 119, when the finger protector 170 is placed in the motion detector 100. The dimensions and placement of the projection portions 192, 194, 196 and 198 are such that the projection portions 192, 194, 196 and 198 sufficiently prevent contact with the infrared detector 118 to comply with UL773A standards, while only blocking in shape minimizing the passage of infrared energy in aperture 174 at certain angles. An example of an articulated probe 304 having dimensions in accordance with UL773A, is shown in Figures 10-13. In particular, the articulated probe 304 has a tip portion 306 and a base portion 308. The articulated probe 304 has the dimensions P1-P25 which are as follows: Pl = 97.0 mm; P2 = 78.0 mm; P3 = 0.05 mm; P4 = 0.05 mm; P5 = 0.05 mm; P6 = 0.05 mm; P7 = 16.0 mm; P8 = 25.4 mm; P9 = 0.05 mm; PIO = 50.0 mm; Pll = 78.0 mm; P12 = 234.0 mm; P13 = 154.0 mm; P14 = 136.0 mm; P15 = 100.0 mm; P16 = 96.0 mm; P17 = 90.0 mm; P18 = 60.0 mm; P18 = 30.0 mm; P20 = 5.0 mm; P21 = 5.8 mm; P22 = 15.0 mm, P23 = 19.0 mm; p24 = 21.5 mm and P25 = 25.4 mm. Similarly, the distal tip of the tip portion 306 has a radius PR1 of about 3.5 mm and the base portion 308 has a radius PR2 and PR3 each of about 25 mm. Also, the distal end of the tip portion 306 is inclined at an angle? Pl of about 302, as shown, as further indicated, the tip portion 306 includes a first section 310, a second section 312 and a third section 314, which are pivotally coupled together by screws 316. As shown in Figure 14, the orientation and dimensions of the projections 192-198 prevent the distal end of the tip portion 306 from contacting the infrared detector 118. , when the finger protector 170 is placed in the movement detector 100. The projection portions 192-196 prevent the distal end of the tip portion 306 of the articulated probe 304 from contacting the infrared detector 118, regardless of the angle at which the tip portion is attempted to the end aperture 174. Similarly, the portion 191 of rectangular configuration prevents the distal end of the tip portion 306 from contacting the detector 119 of ambient light. Thus, the finger protector 170 complies with the guide lines indicated in UL 773A. Although the finger protector 170 is shown as having four projection portions, this finger protector 170 can be configured to include any number of projection portions that make it possible for the finger protector 170 to remain in compliance with the UL 773A standard. It is also preferable that the projection portions be narrow so that they obstruct only a small fraction of the infrared energy that propagates towards the aperture 174, and thus the sensitivity of the motion detector 100 does not significantly decrease. Also, the projections do not need to be spaced circularly around the opening 174 and may have a suitable spacing arrangement. Specifically, the projection portions 192-198 are positioned to minimize the obstruction of infrared energy, or any other spectral energy (e.g., visible light, etc.) that propagates to the infrared detector 118, so that there is no attenuation of passive infrared energy or visible light occurring along the horizontal axis, which extends normal to the surface of the infrared detector 118 and the shadow of the infrared detector 118 lens is minimized. The projection portions 192-198 positioned as exemplified above, are essentially aligned with a segment-to-segment bonding area on the lens of the infrared detector 118, when a minimum gain occurs. Any attenuation that could be caused by the projection portions 192-198 occurs for the infrared energy that propagates to the infrared detector 118 at angles with respect to the horizontal axis, which will result in the trajectory of the infrared energy intercepting any of the portions of projection 192-198. A finger guard 318, according to another embodiment of the present invention, is shown in Figures 15 and 16. This finger guard 318 is made of a plastic, a composite material or any other suitable material, as required by UL773A . The finger protector 318 includes a cylindrical or substantially cylindrical base, 320, having a disc-shaped portion 322 and a cylindrically or substantially cylindrically shaped portion 324. The projection portions 326, 328 and 330 extend from the upper side of the cylindrical portion 324, as indicated. Although not shown in Figure 15, for illustrative purposes, another set of projection portions 332, 334 and 336 extend upward from the top of cylindrical portion 324 and face projection portions 326, 328 and 330, respectively, as shown in Figure 16.

The finger guard 318 is placed over the infrared detector 118 so that this infrared detector 118 is received in the opening 325 in the cylindrical portion 324, and is positioned so that the tab 337 in the infrared detector 118 extends through the opening 338 in the cylindrical portion 324. Therefore, the projection portions 326-336 prevent the articulated probe 304 (see Figures 10-13) from contact with the infrared detector 118, regardless of the angle at which the articulated probe 304 attempts to enter the opening 325 in the cylindrical portion 324. Thus, the finger protector 318 also complies with the UL773A standard for the infrared detector 118. Alternatively, the finger guard may be arranged as a finger guard 339, which includes a pair of finger guard portions 340 and 342, placed under pressure. As indicated, the portion 340 of the finger guard includes three projection portions, 344, 346 and 348 and the finger guard portion 342 includes the projection portions 350, 352 and 354. The finger guard portions 342 and 344 are removably positioned on the infrared detector 118 directly or on a sleeve member 355 which has a cylindrically shaped portion surrounding the infrared detector 318 and a portion thereof. rectangular 357 surrounding the detector 119 of ambient light. The portions, 342 and 344, of the finger guard and the sleeve member 355, each are made of plastic, a composite or any other suitable material, as regulated by UL773A. The projection portions 344-354 prevent the articulated probe 304 (see Figures 10-13) from contacting the infrared detector 318, regardless of the angle at which the articulated probe 304 attempts to make contact with the infrared detector 118. The portion rectangular 357 prevents the articulated probe 304 from contacting the ambient light detector 119, from any angle. Thus, the finger protector 338 also fully complies with the UL773A standard for the infrared detector 118 and the ambient light detector 119. Alternatively, instead of including the projection portions, as discussed above, the finger protector 320 and the sleeve member 355 may include an insulating window that transmits infrared light (not shown), made of, for example, polyethylene high density, silicon, germanium or any other suitable material, covering the infrared detector 118. Thus, the window allows the infrared energy to pass to the infrared detector 118 while also preventing physical contact with the infrared detector 118.

Instead of supplying a mechanical device, such as a finger guard, which prevents contact with the infrared detector 118, to prevent the possibility of an electrical shock, a current limiting circuit can be coupled to the infrared detector 118 to limit the current that the infrared detector 118 receives from the power supply circuit 110. That is, as shown schematically in Figure 18, the infrared detector 118 includes terminals 358 and 360 which are coupled to the circuit system (not shown) and thus receive power from board 110 of the power supply circuit (see Figure 1) . The infrared detector 118 further includes a terminal 362. A current limiting circuit 364, according to one embodiment of the present invention, is coupled to the terminal 362 of the infrared detector 118 as shown. This current limiting circuit, 364, does not provide an optical attenuation to the infrared energy or the ambient light that is received by the infrared detector 118. The current limiting circuit, 364, includes a resistor 366 in a plurality of capacitors 368 and 370. In this example, the resistor 366 has a resistance value of 830 kO and the capacitors 368 and 370 each have a capacitance of 500 pF. A resistor terminal 366 is connected directly to terminal 362 of the infrared detector 118, and the other terminal of the resistor 366 is connected to ground. One terminal of the capacitor 368 is directly connected to the terminal 362 of the infrared detector 118 and the other terminal of the capacitor 368 is connected to the terminal of the capacitor 370. The other terminal of the capacitor 370 is connected to ground, as indicated. Therefore, in this example, the capacitors 368 and 370 are coupled in series with each other to provide a high frequency noise derivation path and are coupled in parallel with the resistor 366 that supplies the connection limited to the direct current. The current limiting circuit 364 operates to limit the current that is provided to the infrared detector 118 to less than about 500 μA. The current limiting circuit 364, therefore, complies with the UL733A standard in that it limits the maximum current that can be provided to an uninsulated electronic component (i.e. the infrared detector 118) to less than 500 μA. Although the current limiting circuit 364, in this example, includes a resistor 366 and two capacitors 368 and 370, the circuit can include any number of resistors and capacitors, which have any suitable resistance and capacitance value, which will limit the current maximum received by the infrared detector 118 to less than 500 μA. Likewise, it is preferable to use at least two capacitors, as shown, to supply the desired amount of capacitance, instead of a capacitor having the desired capacitance value. Therefore, if one of the capacitors 368 or 370 becomes short-circuited, the other capacitor will supply sufficient capacitance to limit the maximum current provided to the infrared detector 118 to less than 500 μA. However, if only one capacitor is used and it becomes short-circuited, the resistor will be short-circuited by the capacitor, which will not limit the maximum current provided to the infrared detector 118 below 500 μA. Similarly, although not shown, a current limiting circuit, similar to circuit 364, may be coupled to ambient light detector 119 to limit the current provided to this detector 119 of ambient light to less than 500 μA. Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications to exemplary embodiments are possible, without departing materially from the novel teachings and advantages of this invention. Therefore, it is intended that all such modifications be included within the scope of the invention, as defined by the following claims.

Claims (21)

1. CLAIMS 1. An apparatus, for use with an electronic device, which restricts physical access to a component of this electronic device, which has an external surface not isolated, adapted to carry a voltage, this apparatus comprises: a housing, which it defines a first opening and is adapted for mounting to the electronic device, so that this first opening allows the passage of the spectral energy therethrough to the component; and a projection array, extending from the housing and defining a second opening, which allows the spectral energy to pass through it, to pass through the first opening to the component, this projection arrangement limits physical access to the surface of the component through the first opening.
2. 2. An apparatus, as claimed in claim 1, wherein the projection array comprises: a first projection portion, extending from the housing in a first direction, transverse to the first plane in which the housing defines the first aperture; and a second projection portion, extending from the first projection portion, along a second plane transverse to the first direction and having an edge defining at least a portion of a perimeter of the second aperture.
3. 3. An apparatus, as claimed in claim 1, wherein: the second projection portion comprises a plurality of projections, each extending substantially along the second plane.
4. 4. An apparatus, as claimed in claim 3, wherein: each of the projections extends along the second plane that faces another of the projections.
5. 5. An apparatus, as claimed in claim 1, wherein: the array of projections comprises a plurality of these projections, each extending from the housing around the first aperture, in a transverse direction a plane on which the housing defines the first opening.
6. An apparatus, as claimed in claim 5, in which at least one of the projections in this array of projections comprises: a first projection portion, extending from the housing in a direction of transverse extension to a plane in which this housing defines the first opening; and a second projection portion, extending from the first projection portion in a direction transverse to the extension direction, and having an edge defining at least a portion of the perimeter of the second aperture.
7. 7. An apparatus, as claimed in claim 6, wherein: each of the projections comprises a first projection and a second projection.
8. 8. An apparatus, as claimed in claim 5, in which: the projections are disposed at substantially equal intervals around the first opening.
9. 9. An apparatus, as claimed in claim 5, wherein: the array of projections comprises four of these projections, spaced substantially at intervals of 902 about a central axis of the first aperture.
10. 10. An apparatus, as claimed in claim 1, wherein: the housing defines the first opening in a plane; and the arrangement of projections allows the spectral energy to enter the first aperture at angles varying from a normal angle to the plane to an angle substantially parallel to this plane.
11. 11. An apparatus, as claimed in claim 1, in which: the housing and arrangement of projections comprise a composite material.
12. 12. An apparatus, as claimed in claim 1, wherein the component is an infrared detector and the arrangement of projections limits physical access to the infrared detector while allowing infrared energy to pass to the infrared detector.
13. 13. An apparatus, as claimed in claim 1, wherein: the electronic device includes a second component, which has an uninsulated external surface, adapted to carry a voltage; and the housing defines a third opening, which allows passage of light therethrough to the second component, and includes a wall portion, which comprises at least a portion of the third opening, which restricts physical access to the second. component through this third opening.
14. 14. An apparatus, as claimed in claim 13, in which: the second component is a detector of ambient light, and the wall portion limits physical access to the ambient light detector through the second aperture, while allowing the ambient light passes to the ambient light detector through the second opening.
15. 15. An apparatus, for use with an electronic device, for limiting a current provided to an infrared detector of this electronic device from a circuit of this electronic device, the apparatus comprises: a resistive element, adapted to couple a terminal of the infrared detector to ground; and a capacitive element, adapted to couple the terminal of the infrared detector to ground; these resistor and capacitive elements have resistance and capacitance values, respectively, which limit the current to less than about 500 μA.
16. 16. An apparatus, as claimed in claim 15, wherein: the capacitance element comprises a plurality of capacitors coupled in series.
17. 17. An apparatus, as claimed in claim 16, wherein: each of the capacitors has a capacitance of approximately 500 pF.
18. 18. An apparatus, as claimed in claim 15, in which: the resistive element has a value of at least about 820 kO.
19. 19. An apparatus, as claimed in claim 15, in which: the resistive and capacitive elements are coupled in parallel between the terminal and ground.
20. 20. A method for restricting physical access to a spectral energy detector of an electrical device, having an uninsulated external surface, adapted to carry a voltage, this method comprises the steps of: providing a housing, defining a first opening , and an array of projections extending from the housing and defining a second opening; and placing the housing in the electronic device, so that this first opening is substantially aligned with the component, the arrangement of projections allows the spectral energy to pass through the second opening, then pass through the first opening to the component , while limiting physical access to the surface of the component through this first opening.
21. 21. A method for limiting a current provided to a spectral energy detector of an electronic device from a circuit of this electronic device, comprising the steps of: coupling a current limiting circuit, comprising a resistive element and a capacitive element coupled in parallel, between a terminal of the spectral energy detector and ground; and operating the current limiting circuit, to limit this current to less than about 500 μA.