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Publication numberUS3621164 A
Publication typeGrant
Publication dateNov 16, 1971
Filing dateJan 5, 1970
Priority dateJan 5, 1970
Publication numberUS 3621164 A, US 3621164A, US-A-3621164, US3621164 A, US3621164A
InventorsBacker Stanley
Original AssigneeBacker Stanley
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus for discharging static electricity
US 3621164 A
Abstract  available in
Images(3)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

United States Patent [72] Inventor Stanley Backer 5 Irving Road, Waban, Mass. 02168 [21] Appl. No. 569 [22] Filed Jan. 5, 1970 [45] Patented Nov. 16, 1971 [54] APPARATUS FOR DISCHARGING STATIC ELECTRICITY 13 Claims, 19 Drawing Figs. [52] US. Cl ZOO/61.58, 317/2 R [51] Int.Cl H01h3/l6 [50] Field of Search ZOO/61.58. 157,169 PB, 172 A; 317/2 R; 174/5 R, 5.1, 5.2 [56] References Cited UNITED STATES PATENTS 559,416 5/1896 Soper 200/172 X 2,038,323 4/1936 Thomas 200/61.58 3,462,! 83 8/1969 Dudley et a1 317/2 R X ABSTRACT: Apparatus is disclosed for use in conjunction with operators such as doorknobs, switches, pushbuttons and the like to enable a person to effect a painless discharge of an accumulated charge of electricity when the person contacts the operators. in each embodiment the apparatus comprises two electrically conductive members one of which carries a contact surface which protrudes therefrom toward the other member but which is normally spaced therefrom by means of insulation including an airgap. Means is provided to bias the members away from one another so that the accumulated static charge is transferred from the person when he touches the member carrying the contact surface and urges it against the biasing means into engagement with or at least into proximity with the other member. The embodiments associated with doorknob structures are constructed to transfer static electricity when the knob is pushed, pulled or rotated; the embodiment associated with the pushbutton is constructed to transfer static electricity when the button is pushed; and the embodiment associated with the switch is constructed to operate when the switch is operated.

PATENTEnuuv 1s |97l 3.621.164

sum 3 or 3 FIGIS.

INVENTORZ STANLEY BACKER BY Wan d Warz AT TYS.

APPARATUS FOR DISCI-IARGING STATIC ELECTRICITY The present invention relates to apparatus for discharging static electricity, and more particularly, the present invention relates to apparatus for enabling a person to effect a painless discharge of static electricity when operating such things as metallic doorknobs, electrical toggle switches, pushbuttons, or the like.

It is well-known that a charge of static electricity may be generated by a person walking across a floor covered by carpeting of certain synthetic materials or when wearing clothing manufactured from certain synthetic fibers. Under conditions of low-relative humidity, a relatively large electrical potential may be developed. When the person extends his fingers or hand while attempting to touch an object at a lower electrical potential, current flows from the extremities thereof, causing the person to feel a shocking sensation. Thus, at present, the performance of ordinary acts such as grasping a metallic doorknob on a door, touching the metal plate on a toggle switch or depressing a metallic pushbutton often causes people considerable annoyance and discomfort.

In an efiort to obviate the foregoing disadvantages, some carpet manufacturers provide metal ground wires in their synthetic carpets. This approach to the problem has not been satisfactory, however, because it has not been entirely effective. In addition, synthetic carpeting having metal ground wires is expensive to manufacture. Insulators, such as rubber covers, have also been installed on doorknobs and the like in another attempt to solve the shock problem. However, the use of such devices only postpones the shock which a person ultimately receives when touching a metallic object at an electrical potential lower than himself.

In view of the foregoing, it is the primary object of the present invention to provide novel apparatus for enabling a person to painlessly discharge an accumulated charge of static electricity. V

It is another object of the present invention to provide simple and inexpensive apparatus for use in conjunction with doorknobs, toggle switches, pushbuttons and like structures to enable a person to operate these devices without receiving an electrical shock after walking across a floor covered by carpeting of certain synthetic materials or when wearing clothing manufactured from certain synthetic fibers.

As a further object, the present invention provides improved doorknob structures which operate to discharge static electricity when manually engaged by a person and either pushed, pulled or rotated to actuate the latching assembly connected thereto.

It is a still further object of the present invention to provide unique apparatus for use on a conventional doorknob to enable a person to effect a painless discharge of static electricity when gripping the knob.

As another object, the present invention provides a unique cap for attachment to a conventional pushbutton to automatically effect a discharge of static electricity from a person when the button is depressed.

A still further object of the present invention is to provide a novel metallic element associated with a wall-type toggle switch for discharging static electricity from a person when the switch is operated.

The present invention also has as an object the provision of discharge apparatus to enable a person to periodically effect a positive and complete discharge of static electricity.

More specifically, each embodiment of the discharge apparatus of the present invention comprises first and second electrically conductive members disposed in normally spaced apart relation with one of the members carrying contact means protruding therefrom toward the other. Insulation means, including an airgap, is provided between the members; and means, including a resilient insulator, is provided to bias the members away from one another to effect the required spacing. Static electricity is painlessly transferred from a person and to the first member when the person engages the second member and displaces it against its bias toward the first member and into engagement therewith or at least sufficiently close thereto to cause the static electricity to jump from the second member to the first member.

In the embodiments of the invention preferred for use with doorknobs, the first and second members are formed integrally with a doorknob structure and in other embodiments the first member is a doorknob and the second member is a removable device carried thereon, the apparatus of these embodiments operating to discharge static electricity when the knob is pulled, pushed, rotated or squeezed.

In the embodiments preferred for use with switches, the first member is a metallic receptacle mounting a cover through which the handle of a toggle switch projects and the second member is a spring element mounted on the front of the cover' to discharge static electricity when the spring element is urged against the cover and the switch is operated. In a further em bodiment, the first member includes a metallic plate slidably mounting a pushbutton and the second member includes a cap surrounding terminus of the button and insulated therefrom, the cap having an annular surface confronting the plate a spaced distance therefrom and being operable to transfer static electricity to the plate when the button is depressed and the surface engages the plate.

These and other objects, features and advantages of the present invention should become apparent from the following description when taken in conjunction with the accompanying drawings in which:

FIGS. 1, 3 and 5 are partially sectioned side elevational views of three different doorknob structures embodying the present invention;

FIGS. 2, 4 and 6 are sectional views taken along lines 2-2, 4-4 and 6-6 of FIGS. 1, 3 and 5 respectively;

FIG. 7 is a partially sectioned, side elevational view of a conventional doorknob mounting removable apparatus embodying the present invention;

FIG. 8 is a fragmentary sectional view taken along line 8-8 of FIG. 7;

FIGS. 9 and 10 are fragmentary sectional views of the apparatus of FIG. 7 illustrating portions thereof in operating positions;

FIG. 11 is a partially sectioned, side elevational view of a conventional doorknob mounting removable squeeze-type discharge apparatus embodying the present invention;

FIG. 12 is a sectional view taken along line 12-12 of FIG. 1 1;

FIG. 13 is an inverted plan view of the knob of FIG. 11;

FIG. 14 is a sectional view of a pushbutton mounting discharge apparatus embodying the present invention;

FIG. 15 is a partially sectioned, side elevational view of an electrical toggle switch mounting discharge apparatus embodying the present invention;

FIG. 16 is a front elevational view of the apparatus illustrated in FIG. 15;

FIG. 17 is a view similar to FIG. 15 but illustrating the discharge apparatus in one of its operating positions for transferring static electricity;

FIG. 18 is a detached perspective view illustrating the underside of the apparatus of FIGS. 15-17; and

FIG. 19 is an enlarged fragmentary sectional view of the upper end of the discharge apparatus illustrated in FIGS. 15-17.

Referring now to the drawings, there are disclosed in FIGS. 1-6 (Sheet 1) doorknob structures 10, 30 and 60 embodying the present invention. The structure of FIGS. 1 and 2 operates to discharge static electricity when the knob 10 is pulled rearwardly or displaced rightward; the structure of FIGS. 3 and 4 operates to discharge static electricity when the knob 30 is pushed forwardly or displaced leftward; and the structure of FIGS. 5 and 6 operates to discharge static electricity when the knob 50 is rotated in the clockwise or counterclockwise directions. Common to each of the aforementioned doorknob structures is a first member or shank, ll 31 and 51 rotatable in a collar 12, 32 and 52 comprising part of a latching assembly 13, 33 and 53 mounted in a door 14, 34 and 54 respectively and being operable upon rotation of the shank. A second member or hollow knob 15, 35 and 55 surrounds the terminal portions of the respective shanks and is operable, in a manner to be described, to discharge static electricity, and actuate the respective latching assemblies.

As noted heretofore, it is well-known that during periods of low-relative humidity a person may accumulate a charge of static electricity by walking across a floor covered with certain synthetic carpeting materials or when wearing clothing made from certain synthetic fabrics. Thereafter, when extending his fingers to turn a doorknob, to depress an elevator call button, to operate a toggle switch, or to actuate like devices, an arc of electricity may jump from the extremity of his fingers and to the device, causing the sensation of electric shock to be felt. The magnitude of the shock, of course, depends on the quantity of charge generated and the potential difference between the person and the device, with well-grounded objects such as doorknobs on metal doors, metallic switch cover plates causing substantial discomfort when touched.

The foregoing disadvantages are obviated by the present invention which, in accordance with its primary object, provides apparatus for use in conjunction with the aforementioned and like devices to enable a person to touch and operate the devices without receiving an electrical shock. To this end, the first and second members, i.e., the shank 11 and knob in the FIG. 1 embodiment is spaced apart by means of insulation which provides a normally interrupted electron flow path between the knob 15 and the shank 11 but which provides a completed flow path when the knob is pulled. In addition, the knob 15 is mounted onto its shank 11 in a manner which causes the latching assembly 13 to be actuated when the knob 15 is rotated on its axis A in either the clockwise or counterclockwise directions. For these purposes, the insulation means comprises a faceted molded insulator 16 mounted in the terminal end of the shank 11, a band of insulation 17 on the periphery of the shank adjacent its terminus, and an airgap 18 surrounding the bank 17 and the end of the shank 11. The knob 15 is mounted for axial displacement forwardly and rearwardly on the shank 11 by means of a forwardly protruding stem 15' which is slidably received in an axial bore located centrally in the insulator 16. Means is also provided to couple the knob 15 to the shank 11 to prevent relative rotation therebetween. In the present instance, the coupling means comprises three elongated catches 19,19 mounted in rearwardly opening cavities in the shank 11 which register with a like number of forwardly opening cavities in the knob 15. The catches 19,19 extend axially a spaced distance outwardly from the axis A, and the cavities in the knob 15 threadedly mount set screws 20,20 which may be rotated, as will be more fully described hereinafter, to vary the airgap 18. Thus, with this structure, rotation of the knob 15 causes the shank l1 and the latching assembly 13 to operate through the interengagement of the catches 19,19.

In order to complete the electron flow path when the knob 15 is pulled rearwardly or displaced rightward, contact means is provided on the knob 15 and the shank 11. As may be seen in FIGS. 1 and 2, the contact means comprises forwardly facing arcuate surfaces 21,21 on circumferentially interrupted flanges 11a, Ila extending radially outward on the terminus of the shank l1 and a like number of circumferentially interrupted rearwardly facing arcuate surfaces 150, 15a in registry therewith on the knob 15. Each surface 15a has a raised portion tapering toward an apex 15b which confronts the surface on the flange 11a and engages it when the knob is pulled. The surfaces are interrupted to enable the knob 15 to be mounted on its shank 11 by aligning the interruptions on the knob with the flanges 11a, 11a on the shank 11, displacing the knob axially, and then rotating the knob to cause the surfaces to register with one another.

For the purpose of normally maintaining the airgap l8 the apexes 15b, 15b from the surface of the flanges 11a, 110. Also, means is provided to limit the airgap l8 and to adjust the applied biasing force. In the embodiment of FIG. 1, the biasing means comprises a compression spring 23 engaged between an annular shoulder 24 in an axial recess in the knob 15 and the head 25 of a threaded fastener 26 threaded into the insulator 16. In the present instance, the threaded fastener 26 is a bolt which is operable upon rotation in the clockwise direction (FIG. 2) to compress the spring 23 and increase the pulling force required to interengage the contact surfaces and operable upon rotation in the counterclockwise direction to relieve the compression of the spring 23 and reduce the pulling force required to interengage the contact surfaces. The spacing between the contact surfaces 11a and 15a is limited by means of the catch 19 which is mounted in the cavities in the knob 15 and insulator 16 and which is engaged at its rearwardmost end by the setscrew 20. With this structure, rotation of any one of the set screws 20 in the clockwise direction (FIG. 2) causes the contact surface spacing to decrease, and rotation of the setscrew in the counterclockwise direction causes the contact surface spacing to increase, as long as the spring 23 is compressed. Thus, should it become necessary to adjust the airgap 18, for example, to ensure shock resistance when large electrical potentials are developed, or should it be desirable to adjust the required pulling force, the setscrews 20,20 and the threaded fastener 26 may be rotated accordingly, The knob also has a cover 28 which masks the aforementioned adjusting mechanisms and provides a pleasing appearance for the knob assembly 10.

In the embodiment illustrated in FIGS. 3 and 4, the knob structure 30 operates upon forward displacement of the knob 35 on the axis B relative to the shank 31 to cause the spring between the contact surfaces to decrease and the surfaces to ultimately interengage one another. In this embodiment, the shank 31 has an arcuate, in the present instance annular contact surface 31a and the knob 35 has a like contact surface 35a in registry therewith which tapers to an apex 35b a spaced distance therefrom. Like the knob assembly 10 of FIG. 1, the FIG. 3 embodiment has an insulator 36 mounted in the end of the shank 31, and the insulator 36 has a bore slidably receiving a forwardly protruding stem 35' on the knob. In the present instance, the contact apex 35b of the knob 35 is spaced from the shank surface 31a by means of catches 39,39 mounted in circumferentially spaced axially extending cavities in the insulator 36 and in like cavities in the knob 35. A compression spring 37 engages between the catch 39 and the bottom of the shank-cavity to urge one end of the catch 39 against a setscrew 40 threadedly engaged in internal threads in the catchcavity in the knob 35. The spacing and hence the airgap 38 between the apex 35b and the contact surface on the shank l2 limited by means of a bolt 42 threaded into the shank 31 and having its head 43 engaging the knob 35. Similarly to the aforedescribed FIG. 1 embodiment, the spacing may be decreased by rotating the bolt 42 in the clockwise direction FIG. 4) and the spacing may be increased by rotating the bolt 42 in the counterclockwise direction. If desired, the amount of force required to effect interengagement of the contact surfaces may be adjusted by rotating the setscrews 40, clockwise rotation increasing the required interengagement force and counterclockwise rotation decreasing the interengagement force. As in the FIG. 1 embodiment, a cover 48 on the front of the knob masks the aforementioned adjusting mechanism.

In each of the aforedescribed embodiments, the knobs are insulated from the shank so that there is no substantial discharge of static electricity when the knob is first grasped. When the knob is thereafter operated, contact between the members is effected remotely from the point where the knob is grasped, so as to avoid discharge in the region of the hand. The discharge is facilitated by the use of the apex to cooperate with the contacting surface, and this point of discharge is encased within the knob.

The knob assembly 50 illustrated in FIGS. 5 and 6 operates upon rotation of the knob 55 in either the clockwise or counterclockwise direction to effect interengagement of the contact surfaces. In this embodiment, an insulator 56 is fixedly secured to the shank 51 and rotatably mounts the knob 55 thereon. The contact surfaces are disposed in a circle concentric with the axis of rotation C of the knob 55 and interengage one another upon a predetermined amount of rotation of the knob 55 relative to the shank 51. In the present instance, the contact surfaces are provided on two pairs of pins 51a, 55a and 51a, 55a which extend along the axis C on diametrical sides thereof. The pins 51a, 51a are pressed into bores in the shank 51 and extend through the insulator 56 to terminate adjacent the inside of the knob 55. The pins 55a, 550 are similarly mounted in the knob 55 and terminate adjacent to the insulator 56 so that each pair 51a and 55a of the pins is disposed in circumferentially spaced side-by-side relation. The pairs of pins are maintained in normally spaced relation by means of a resilient member which engages the insulator 56 and the knob 55. In the present instance, as may be seen in FIG. 5, the resilient member is a torsion spring 57 having an axially extending arm mounted in the insulator 56 and another axially extending arm mounted in the knob 55. The knob 55 is secured to the shank 51 by means of a bolt 62 threadedly received in the insulator 56 and extending coaxially through the coils of the torsion spring 57 with its head engaging the knob 55. Thus, when the knob 55 is rotated in the clockwise direction (FIG. 6) the spacing between the top pair of pins decreases to transfer static electricity from the knob 55 to the shank 51, and when the knob 55 is rotated in the counterclockwise direction, the spacing between the bottom pair of pins decreases to transfer static electricity within the confines of the knob, continued rotation of the knob in either of the aforementioned directions effecting interengagement of the surfaces and actuation of the latching assembly 53. Like the aforedescribed embodiments, a cover 58 is provided on the front of the knob 55.

In accordance with another object of the present invention, apparatus may be provided for use with conventional doorknobs to effect the discharge of static electricity from a person when the person reaches to grasp the knob. In the embodiment of FIGS. 7-10 (Sheet 2) static electricity is discharged when the doorknob assembly 70 is pushed or turned, and in the embodiment of FIGS. 1113, static electricity is discharged when the knob assembly 90 is squeezed. As may be seen in FIG. 7, the knob assembly 70 comprises a first electrically conductive member or knob 75 and a second electrically conductive member 76 surrounding the knob 75. The cover 76 extends across the front of the knob 75 and inwardly toward a shank 71 behind the knob. The cover 76 is spaced from the knob by means of insulation 77 which frictionally engages both the cover 76 and the periphery of the knob 75 so that the knob 75 rotates when the cover 76 is rotated. In this embodiment, contact surfaces are provided by means of a series of pins 80,80 carried by the insulator 77 in circumferentially spaced relation around the periphery of the knob 75 and a pair of tabs 81,81 associated with each pin. Each of the pins 80 has its head engaging the knob 75 and its stem projecting radially outward therefrom, and each pair of the tabs 81 is integral with the cover 76, extending inwardly therefrom in registry with opposite sides of each pin stem 80 b. The insulator 77 is recessed as indicated at 83 in the vicinity of the pins and tabs and is resilient so that the tabs 81, 81 are normally spaced from the stems of their associated pins within the recesses 83 but so that they may be engaged therewith for transferring static electricity within the confines of the recesses 83 when the cover 76 is rotated in either of the clockwise or counterclockwise directions (See FIG. 9). If desired, a tab 82 may be formed on the cover 76 to project inwardly toward the front of the knob 75 for effecting contact when the cover 76 is displaced forwardly toward the knob with a push type of motion similar to that required to effect interengagement of the contact surfaces in the FIG. 3 embodiment (See FIG. Thus, with this structure, the cover 76 may be mounted on the conventional doorknob to thereby enable a person to discharge static electricity by either pushing on the cover or turning the cover in either the clockwise or counterclockwise directions.

In the embodiment illustrated in FIGS. 11-13, static electricity is discharged when a squeezing action is applied to the doorknob assembly 90. For this purpose a first member, in the present instance a doorknob 91 is surrounded by a second member or band 92 which surrounds a major portion of its periphery. The bank 92 is spaced from the periphery of the knob 91 by means of an insulator 93 which covers the front of the knob and which has a pair of upstanding flanges 93a, 93a engaging opposite edges of the band 92 to prevent the band from being displaced axially relative to the knob 90. In the present instance, the bank 92 is formed of resilient springlike material having a natural radius of curvature which is slightly less than the radius of curvature of the outer periphery of the insulator 93. Thus, by virtue of its inherent elasticity, the bank 92 clamps itself onto the insulator 93. In this embodiment, the contact surfaces include the periphery of the knob 91 and a series of tabs 95,95 formed integrally with the band 92 and projecting inwardly through a like series of recesses or holes 96,96 in the insulator 93 and toward the periphery of the knob. The insulator 93 is sized to frictionally engage the knob 91 and the band 92 to cause the knob 91 to rotate when the band 92 is rotated. In addition, the insulator is formed of an elastically deformable or compressible substance which enables the tabs 95,95 to be engaged against the periphery of the knob within the recesses 96 for discharging static electricity thereto when the bank 92 is squeezed.

The present invention is also adapted for use in conjunction with metallic pushbuttons, for example an elevator call button -100(FIG. 14). As may be seen therein, a first member, in the present instance a metallic plate 101 slidably mounts a plunger 102 for displacement theretoward to effect operation of a switch assembly 103 mounted behind the plate 101. A cap of second metallic member 104 surrounds the terminus of the plunger 102 and is spaced therefrom by means of insulation 105. The cap 104 has a central thumbrest portion 109 and an annular wall 106 which extends along the plunger 102 and toward the plate 101 and which terminates in an apex 106b a spaced distance from the plate 101. In this embodiment, the cap 104 is normally biased away from the plate 101 by means of a compression spring 107 which is mounted in the plunger 102. The spacing between the apex and the plate 101 is limited by means of a split washer 108 mounted in a peripheral groove in the plunger 102 and engageable against the inside of the plate 101. With this structure, static electricity may be discharged from a person and the switch assembly 103 actuated when the person touches the thumbrest 109 of the cap 104 and depresses the plunger 102 toward the plate 101 to cause the apex 106b of the annular wall 106 to engage the plate 101. The point of static discharge between the apex 106b and the contact surface of the plate 101 is remote from the thumbrest 109.

In a further embodiment, the present invention provides apparatus for use in conjunction with an electrical toggle switch 200 to enable a person to discharge static electricity when the switch is actuated. To this end, a first member, in the present instance a metallic switch cover plate 201 (FIG. 15, Sheet 3) spans across an opening in a wall 202 mounting a box 203 in which is carried a conventional electrical toggle switch 200. The switch 200 has a handle or operator 204 projecting outwardly through an elongated slot 205 in the cover plate 201 and operable between alternate positions adjacent each end of the slot 205. The cover plate 201 is mounted to the box 203 by means of threaded fasteners, in the present instance screws 206, 206 which are threaded into the conventional sockets of a switch-mounting strap 200 which is mounted on mounting ears 207, 207 of the box 203.

In order to prevent a person from receiving a shock when his finger is positioned in close proximity to the plate 201 and handle 204, a second member or element 210 is mounted on the front of the plate 201 and insulated spaced distance therefrom. 1n the illustrated embodiment, the second member comprises an elongated metal strip having intumed flanges 211, 211 through which pass the screws 206, 206. The strip is insulated from the cover plate 201 by means of nonconductive shouldered washers 213, 213 (P16. 19) disposed intermediate the plate and one side of the flanges 211, 211 and nonconductive washers 215, 215 disposed between the other side of the flanges 211, 211 and the heads of the screws 206, 206. In the present instance, the entire cover plate 201 is metallic and electrical communication between the plate and the box 203 is provided by means of metallic washers 217, 217 disposed intermediate the inside of the plate 201 and the lips 207, 207 around the screws 206, 206. Thus, when the screws 206, 206 are rotated, a clamping action occurs between the cover plate 201 and the lips 207, 207 to effect electrical communication therebetween.

For the purpose of transferring electrical energy from the element 210 to the cover plate 201, contact means, in the present instance tabs 220, 220 are provided on the element 210. In the present instance, the tabs 220, 220 are formed integrally with the element 210 and protrude therefrom toward the cover plate 201 adjacent opposite ends of an elongated slot 221 which registers with the slot in the cover plate 201 and through which the handle 204 projects. The tabs 220, 220 are normally spaced and biased away from the cover plate 201 by the looped shape of the flanges 211, 211 which operate to prevent a persons fingers from contacting the screws 206, 206 and thereby being shocked, as presently would be possible even with conventional cover plates of nonconductive material such as plastic (See FIG. 17) Each of the tabs 220 is provided with an apex to engage the contact surface of the plate remote from the point where the finger rests on the element 210. If the plate is nonconductive, the apex of the tab 220 may be positioned to engage the screw 206. in addition, as may be seen in FIG. 15, the element 210 is preferably disposed inwardly of the terminus of the handle 204 so that a person is required to displace the element 210 toward the plate and the tabs 220, 220 into contact therewith before being able to flip the handle 204 upwardly or downwardly (See FIG. 17). It is also to be noted that apertures are provided in each end of the element 210 in registry with the screws 206, 206 to receive a screwdriver for rotating the screws to mount and dismount the element 210.

In view of the foregoing, it should be apparent that novel means has now been provided for enabling a person to periodically discharge static electricity while performing routine functions.

While preferred embodiments of the present invention have been described in detail, various modifications, alterations or changes may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

What is claimed is:

1. Apparatus for transferring an accumulated charge of static electricity between a person and an object comprising: first electrically conductive member connected to the object and mounted for rotation an an axis, a second electrically conductive member spaced from said first member and mounted for rotation on an axis coaxial therewith, the conductive portion of said second member being exposed for engagement with the person, means providing electrical insulation on one of said members and an airgap between said first and second members, contact means on said members and carried on at least one of said members and projecting toward the other of said members, said contact means including at least one surface carried by each of said members a spaced distance outwardly from said axis, said surfaces confronting one another and lying in a circle concentric with said axis and being normally disposed in circumferentially spaced relation, and means biasing said contact means on one member away from said other member to normally space said contact therefrom, whereby the spacing between the surfaces may be diminished when the second member is rotated relative to the first member and against said biasing means to thereby effect the transfer of static electricity therebetween.

2. Apparatus according to claim 1 including a latching assembly connected to said first member and being operable upon rotation in selected clockwise and counterclockwise directions, means including a pair of said surfaces carried by each of said members to limit said relative rotation when said second member is rotated in a selected one of said directions, said biasing means connected to said members to normally space said confronting surfaces at substantially equal distances from one another, so that when the second member is rotated in the clockwise direction, the spacing between the confronting surfaces decreases to transfer static electricity to the first member and interengagement of the surfaces causes the first member to rotate for operating the latching assembly, and when the second member is rotated in the counterclockwise direction the spacing between the surfaces decreases to transfer static electricity to the first member and interengagement of the surfaces causes the first member to rotate for operating the latching assembly.

3. Apparatus according to claim 1 wherein said first member includes a metallic doorknob, said second member includes a metallic element surrounding the periphery of said knob, said insulation means includes a resilient substance having an inwardly facing surface frictionally engaging the inner periphery of said element, and being elastically deformable to provide said biasing means, said contact means comprising at least one pin engaging the outer periphery of said knob and projecting radially outward therefrom and at least one inward projection in said metallic element and depending therefrom toward said pin alongside thereof, whereby the pin is engaged by said projection when the metallic element is rotated relative to the knob.

4. Apparatus according to claim 1 wherein said first member includes a metallic knob surrounding the terminal portion of said shank, said contact means comprising metallic studs secured to said shank diametrically with respect to said axis and extending axially toward said knob, and metallic studs secured to said knob and extending axially toward said shank, said studs normally being disposed in spaced side-by-side relation, said insulation means being secured to said shank and having a cylindrical outer periphery rotatably receiving said knob, said biasing means including a torsion spring having one arm engaging in said insulation means and another arm engaging in said knob, and including a threaded fastener threadedly engaging said insulation means on said axis and engaging said knob to rotatably mount said knob adjacent said shank, whereby the studs are operatively engaged upon rotation of the knob in either the clockwise or counterclockwise direction.

5. Apparatus for transferring an accumulated charge or static electricity between a person and an object comprising a first electrically conductive member connected to the object, a latching assembly connected to said first member and being operable upon rotation of said first member on an axis, a second electrically conductive member spaced from said first member, means slidably mounting said second member to said first member for displacement on said axis, means providing electrical insulation on one of said members and an airgap between said members, contact means on each of said members disposed in axially spaced confronting relation, means biasing said contact means on one member away from said other member to normally space said contact means from one another, means acting counter to said biasing means for limiting the spacing between said contact means and other means to limit relative angular displacement between said members, so that relative axial displacement between the members decreases the spacing between the contact means for transferring electrical energy and rotation of the second member on its axis causes said other means to actuate the latching assembly.

6. Apparatus according to claim 5 wherein said other means includes at least one axially extending cavity spaced outwardly from said axis in one of said members, another axially extending cavity in registry with said one cavity in the other of said members, and. a catch slidably received in said cavities, whereby the interengagement of the catch in the cavities operates to couple the members and prevent relative angular displacement therebetween while permitting axial displacement.

7. Apparatus according to claim 6 wherein said first member includes a doorknob shank and said second member includes a doorknob surrounding the terminal portion of said shank, said insulation means including an insulator mounted in the end of said shank, a stem on said knob slidable in said insulator, said stem having a through bore therein, and said spacing-limiting means including a bolt extending through said bore with its head engaging said knob and its tail carried by said insulator, whereby displacement of the knob axially of said bolt decreases the spacing of the contact means.

8. Apparatus according to claim 7 including an outwardly projecting portion on said shank defining one arcuate surface and an inwardly projecting portion on said knob defining another arcuate surface confronting said shank portion, the arcuate surface on said knob portion having a tapered apex adjacent said shank portion and being engageable therewith upon axial displacement of said knob, said biasing means including a shoulder in said stem-bore and a compression spring surrounding said bolt and seated between said shoulder and said bolt-head to bias said knob axially toward said shank.

9. Apparatus according to claim wherein said contact means includes confronting arcuate surfaces with one surface having a tapered portion terminating in an apex adjacent another arcuate surface, said biasing means including a compression spring mounted in one of the cavities to engage the 10. Apparatus for transferring an accumulated charge of static electricity between a person and an object comprising: a first electrically conductive member connected to the object, said first member including a metallic plate, a plunger slidably mounted in said plate, a second member including a metallic cap mounted on and surrounding said plunger on the end thereof remote from said plate, insulation mea'ns interposed between said cap and said plunger, said cap having a surface spaced from and confronting said plate to provide contact means, means connected to said plunger to bias said plunger and hence said surface away from said plate, whereby the accumulated static electricity is transferred from the cap to the plate when the plunger is displaced toward the plate and the spacing between the surface on the cap and the plate is decreased.

11. Apparatus for transferring an accumulated charge of static electricity between a person and an object comprising: a first electrically conductive member connected to the object and a second electrically conductive member spaced from said first member, a cover disposed intermediate said first and second members and having an elongated slot, an operator protruding forwardly through said slot and operable from in front of said cover between alternate positions adjacent opposite ends of said slot, means adjacent said opposite ends of said slot providing electrical communication between said front of the cover and said first member located behind said cover, the second member including a metallic element having an elongated aperture in registry with said slot and being disposed inwardly of the outermost terminus of said operator, contact means including a tab on the back of said element normally spaced from said electrical communication means and operable upon rearward displacement to establish electrical connection with said electrical communication means, and means including biasing means to mount said element for rearward displacement whereby electrical energy is transferred from the element to the first member behind the cover when the element is displaced by the person actuating said operator.

12. Apparatus according to claim 11 and further including an additional tab on saidelement and wherein said electrical communication means includes metallic portions on said cover in electrical communication with said first member, said biasing means including a resilient intumed flange on said element adjacent opposite ends of said aperture, said element mounting means including an opening in each flange and a threaded fastener extending through each opening and threadedly received in said one member, and insulation means including nonconductive washers between the metallic portions of said cover and the flanges and nonconductive washers and between the heads of the threaded fasteners and the flanges, so that the tabs are normally spaced from the cover by the resiliency of the flanges.

13. Apparatus according to claim 12 and further including an electrical mounting box and wherein said first member includes a strap mounting said box with said operator and confronting the back of the cover, said strap threadedly receiving said threaded fasteners, said element being metallic with said tabs being formed integrally therewith, and including electrically conductive washers disposed intermediate said cover and the strap around the threaded fasteners, so that rotation of the fasteners causes a clamping action to effect electrical communication between the cover and the mounting box.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. Dated November 16 1971 Inventor (8) S tanley Backer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, line 65 "60" should be 50" C01. 3, line 39 "bank should be "band" Col. 6, line 9 DITTO Cole 6, line 4 Col. 6, line 30 Col. 4, line 52 "shank 12" should be "shank is" Col. 6, line 37 "of", first occurrence, should be or 7, li 59 "an", first occurrence should be on C01. 7, line 73 after "Contact" the word "means" omitted Col. 8, line 36 the following omitted after "metallic" and up to "knob" "shank having a terminal portion, said second member includes a metallic" Col. 8, line 53 "or" should be "of Col. 9, line 28 should be "according to claim 7" Signed and sealed this 6th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHL+1R, JR. ROBERT GO'F'TSCHALK Attesting Officer Commissioner of Patents )RM PC4050 (10-69) uscoMM-Dc 60376-P69 I7 U 5 GOVERNMENT PRINTINIS (JFFICl Nil! U356 )34

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3780345 *Sep 14, 1972Dec 18, 1973Earman EStatic electricity deshocker
US3935508 *Aug 5, 1974Jan 27, 1976Burroughs CorporationHigh voltage discharge switch for protecting sensitive electronic equipment and the operators thereof
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US4858061 *Mar 2, 1988Aug 15, 1989General Dynamics Corp.Electrostatic discharge control device
US5283710 *Mar 1, 1993Feb 1, 1994Iomega CorporationElectrostatic discharge shield for switches
US5335137 *Jul 29, 1992Aug 2, 1994Key Tronic CorporationComputer keyboard with electrostatic discharge feature
US6866353 *Dec 27, 2000Mar 15, 2005Shalom WertsbergerElectrostatic discharge device
US9153397 *Dec 11, 2012Oct 6, 2015Cooper Technologies CompanyWiring device with metal switch cover
US20020080549 *Dec 27, 2000Jun 27, 2002Shalom WertsbergerElectrostatic discharge device
US20140158510 *Dec 11, 2012Jun 12, 2014Darron LaceyWiring Device with Metal Switch Cover
DE10251329A1 *Nov 5, 2002May 13, 2004Friedrich FeilckeA method for discharging electrostatic charges from the body has the installation of electrically resistive pads attached in the vicinity of appropriate areas by adhesive
WO1994004012A1 *May 5, 1993Feb 17, 1994Key Tronic CorporationComputer keyboard with electrostatic discharge feature
Classifications
U.S. Classification200/61.58R, 361/220
International ClassificationH05F3/02
Cooperative ClassificationH05F3/02
European ClassificationH05F3/02