Tamper resistant receptacle using cooperating shutter and door

Abstract

A tamper-resistant receptacle having a cooperating shutter and door mechanism that is spring biased in the ready position. Attempted entry into a single blade opening of the receptacle will result in failure to unlock or move the shutter or door members from their protective positions. Simultaneous insertion of both plug blades allows for an unlatching of the shutter members with simultaneous downward rotation of the door member, whereby one or more or a series of cam teeth on the door member engage corresponding cam heads on the shutter member to pull against the spring bias of the device to allow the shutter to move laterally and door to move vertically out of their protective positions providing respective paths for the plug blades to reach the devices' terminals. Upon retraction of the plug blades, the spring bias forces the shutter and door members to return to their ready position.

Description

Attorney Docket No. 34704.2380 (911 -0907 WO)TAMPER RESISTANT RECEPTACLE USING COOPERATING SHUTTER AND DOORCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 682,403, filed August 13, 2024, the contents of which is incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates to tamper resistant electrical receptacles. More particularly, the present disclosure relates to tamper resistant electrical receptacles using a cooperating spring-loaded shutter and door.BACKGROUND

[0003] Tamper resistant receptacles are known in the art. “Tamper Resistant” or “TR” receptacles refers to a type of electrical wiring device, such as a household duplex electrical receptacle, equipped with means for physically blocking access to the electrical contacts which lie below the hot and neutral plug blade openings in the faceplate of the receptacle unless simultaneous force is exerted upon both the hot and neutral plug blade openings at the same time. Currently, NEC Code 406.11 et seq. and other regulatory requirements provide that not only must the outlet openings remain blocked unless force is applied to both openings at the same time, but also that any foreign object 1 / 32 inch or larger, must be prevented from bypassing the blocking member of a plug opening. All new construction and major renovations are mandated to by code to use TR receptacles.

[0004] As will be appreciated, these code requirements were enacted in response to the all-to-often tragic phenomena of a curious child inserting a conductive material, such as a paper clip or small toy, into either the hot or neutral plug blade opening of a receptaclefaceplate and contacting the live hot or neutral electrical contact resulting in electrical shock, burns, or even death.

[0005] In meeting the code standard and providing the level of protection sought from these devices, the art has gravitated towards a configuration of receptacles utilizing cooperating shutter members to block access beyond the faceplate openings of the outlet. Specifically, to ensure that force directed into only one of the two blade openings is prevented from reaching the electrical contact that lies beneath, a sliding shutter mechanism is spring-biased into a position blocking (or “shuttering”) the blade opening from underneath the faceplate. The shutter physically prevents an object entering the blade opening from reaching the electrical contact below that shutter. In order to allow the shutter of a respective blade opening to be uncovered, the spring-bias must be overcome by a camming action caused by the other plug blade during insertion in the other blade opening.

[0006] To this end, the most common prior art configuration of a TR receptacle includes a shutter assembly comprising a pair of cooperating shutters. Each of the shutters includes a blocking portion positioned below a respective one of the blade openings blocking access to the contacts. Each of the shutters also includes a cam portion that extends to the opposite blade opening that receives contact from a plug blade and translates the vertical force of a plug blade and camming action into a lateral sliding displacement of the blocking portion. Thus, force by vertical insertion of a plug-blade on the neutral blade opening will move the shutter from obstructing access to the electrical contact below the hot blade opening, and vice versa.

[0007] Specifically, for example, during insertion of a plug, the neutral blade tine will cam against and past the shutter cam surface forcing the shutter cam arm to move laterally, thereby overcoming the spring bias of the shutter and causing the hot blade shutter blocking portion to slide into a position away from and revealing the electrical contact beneath the hot blade opening. Likewise, force on the hot blade opening will contact the cam surface and allow the blade to cam past and move the arm and compress the spring to move the shutter blocking portion that covers the neutral blade opening out of the way.

[0008] As will be appreciated, with this configuration, when a child tries to insert a toy into either opening of the outlet, the blocking portion of the shutter remains immobile from the spring bias of the opposite shutter and prevents the child from reaching the electrical contact. However, when both blades of an electrical plug contact the shutters simultaneously, the simultaneous force and camming action allows both blades to continue their downward insertion by simultaneously sliding respective shutter blocking portions laterally out of the way of the electrical contacts of the opposite shutter until the blades cam past the shutters and are able to properly “plug in” to the outlet's internal face contacts.

[0009] Existing prior art TR receptacle designs and their operational details are available in U.S. Pat. No. 4,379,607 to Bowden, Jr.; U.S. Pat. No. 7,645,148 to Carbone et aL; and U.S. Pat. No. 8,632,348 to Baldwin, et al. and the references cited therein.

[0010] The proliferation of these important safety devices has led to an appreciation of the issues affecting their effective life span and cost. A presently appreciated issue recognized by the present inventor stems from the need to use a shutter housing component with mounted pairs of shutter members arranged therein to effectuate the safety features of the sliding shutters. Having to deploy an entire sub-housing comprising numerous pieces beneath the faceplate of an outlet may be a significant cost increase, difficult to assembly, and have multiple points of failure thereby hindering the life span.

[0011] The foregoing underscores some of the problems associated with conventional TR receptacles. Furthermore, the foregoing highlights the long-felt, yet unresolved need in the art for a TR receptacle that may extend the useful life of the device. Moreover, the forgoing highlights the long-felt, yet unresolved need in the art for a TR receptacle that has an extended service life at a reasonable cost by using fewer and uncomplicated constituent parts.SUMMARY

[0012] Various embodiments of the present disclosure can overcome various of the aforementioned and other disadvantages associated with known TR receptacles and offer new advantages as well.

[0013] According to various embodiments of the present disclosure there is provided a tamper-resistant receptacle sub-assembly comprising a sub-assembly body that includes integral ramps, pivot points, and / or blocking surfaces to support operational mounting and use of a cooperating shutter and door assembly spring biased in a closed position. The position and configuration of the various features of the sub-assembly may vary between 15-Amp and 20-Amp devices due to the presence or absence of a T- shaped neutral blade opening to accommodate the perpendicular orientation of the neutral prong of the 20-Amp plug.

[0014] According to some embodiments there is provided a sub-assembly housing comprising a single-piece molded body having an open top. In some forms, the body in molded to include pivot points, pin cradles, ramps, support flanges, blocking tabs, and / or spring mounting posts. As will be appreciated, the ability to mold a single body with essential features of the operational mechanism saves on costs, helps ensure structural integrity, lessons parts, reduces points of failure, and ensures quality control.

[0015] In some forms, the sub-assembly includes only four separate parts including the body, a shutter, a door, and a spring member. As will be appreciated, reducing the number of constituent parts saves on costs, reduces potential part failures, and aid in ease of construction and quality control.

[0016] According to some embodiments, there is provided a 15-Amp TR receptacle sub-assembly for use in 15-Amp TR receptacles. The sub-assembly is positioned beneath the hot and neutral plug openings in the TR faceplate. In some forms, the subassembly includes a body member configured to operatively accept a shutter member, a door member, and a spring member. In some forms, the tamper-resistant receptacle sub-assembly comprises a base having at least one ramp member and at least one locking tab; a shutter disposed in said base and pivotable and movable relative to said ramp member, said shutter locked in a ready position by said locking tab and said shutter including a cradle and cam head; a door pivotably disposed in said base and said cradle and locked in a ready position by said cam head biasing the door in a horizontal position, said door including a cam tooth; and a spring member disposed in said housing and biasing said shutter in the ready position; whereby only simultaneous contact force with said shutter and said door allows said shutter to unlatch from the atleast one locking tab and allows said door to pivot vertically thereby camming against the cam head and overcoming the spring bias of the spring member via the contact force to move the shutter down said at least one ramp members.

[0017] In some forms, the base defines a pair of door pin notches and a protruding tab positioned behind said door member. In some forms, the base includes a spring seat.

[0018] In some forms, the shutter includes an upper end, a lower end, and a pair of arms connecting said upper end to said lower end and defining an interior opening. In some forms, the shutter includes a flange member having a spring seat and said spring member is disposed in said interior opening and fixed on a first end at the spring seat.

[0019] In some forms, the shutter includes at least one rocking pin for contacting said at least one ramp members. In some forms, the door includes an axle body on a back end and a blocking surface on a front end, wherein the underside of said blocking surface includes said cam tooth.

[0020] In some forms, the tamper-resistant receptacle sub-assembly is preferably configured such that when a force applied to only the shutter side of the device will fail to unlatch the shutter the locking tabs and force applied to only the door side of the device will fail to rotate the door in the vertical position.

[0021] According to other embodiments of the invention, there is provided a 20-Amp tamper-resistant receptacle sub-assembly comprising a base having at least one ramp member and at least one locking tab; a shutter disposed in said base and pivotable and movable relative to said ramp member, said shutter locked in a ready position by said locking tab and said shutter including at least first and second cam heads; a door pivotably disposed in said base and locked in a ready position by said shutter biasing the door in a horizontal position, said door including at least first and second cam teeth; and a spring member disposed in said housing and biasing said shutter in the ready position; whereby only simultaneous contact force with said shutter and said door allows said shutter to unlatch from the at least one locking tab and allows said door to pivot vertically thereby camming against the first cam head and overcoming the spring bias of the spring member via the contact force to move the shutter down and allow the door torotate to engage the second cam head of said shutter to overcome the bias of spring member and move said shutter and door to the open position.

[0022] In some forms, the shutter includes a third cam head and said door includes a third cam tooth. In some forms, the base includes a spring opening and spring seat on a first side and an elongated ramp and guide slot on a second side.

[0023] In some forms, the shutter includes a spring seat post for said spring member on a first side and a guidepost pin on a second side configured to travel in said guide slot on a second side.

[0024] In some forms, the door comprises a roller axle on a first end, a blocking surface, and a cam tooth extension flap. In some forms, said cam tooth extension flap includes a first main tooth, a pair of second cam teeth, and a pair of third cam teeth positioned for engagement with corresponding cam heads on said shutter.

[0025] In some forms, said cam teeth and said cam heads are positioned to allow downward movement of the extension flap to pull the shutter and overcome the bias of spring member and move the shutter down the ramp members.

[0026] In some forms, said guide slot and said guidepost pin hold the shutter in lateral position during spring compression.

[0027] In some forms, the 20-Amp tamper-resistant receptacle sub-assembly is configured such that a force applied to only the shutter side of the device will fail to unlatch the shutter from the locking tabs and force applied to only the door side of the device will fail to rotate the door in the vertical position.

[0028] In some forms, the body includes protruding tabs whereby an object inserted at an angle will fail to gain sufficient clearance to reach the electric terminals of the device.

[0029] In some forms, there is a tamper-resistant sub-assembly that includes a base, a shutter, a door, and a spring. The base has a lower surface and a wall that extends from the lower surface. A ramp member is coupled to the lower surface and a locking tab is coupled to an upper edge of the wall. The shutter is positioned at least partially within the base. The shutter includes a cradle and a cam head. The door is pivotably disposed in said cradle and locked in a ready position by said cam head biasing the door in a position parallel to the lower surface. The door includes a cam tooth. Thespring member is coupled between the base and the shutter. Only simultaneous contact force with said shutter and said door allows said shutter to unlatch from the locking tab and allows said door to pivot vertically thereby camming against the cam head and overcoming the spring bias of the spring member via the contact force to move the shutter down said ramp member.

[0030] The disclosure herein should become evident to a person of ordinary skill in the art given the following enabling description and drawings. The drawings are for illustration purposes only and are not drawn to scale unless otherwise indicated. The drawings are not intended to limit the scope of the invention. The following enabling disclosure is directed to one of ordinary skill in the art and presupposes that those aspects within the ability of the ordinarily skilled artisan are understood and appreciated.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various aspects and advantageous features of the present disclosure will become more apparent to those of ordinary skill when described in the detailed description of preferred embodiments and reference to the accompany drawing wherein:

[0032] Various aspects and advantageous features of the present disclosure will become more apparent to those of ordinary skill when described in the detailed description of preferred embodiments and reference to the accompany drawing wherein:

[0033] FIG. 1 is an exploded view of the constituent parts of an exemplary 15-Amp tamper resistant receptacle sub-assembly according to various embodiments disclosed herein.

[0034] FIGS. 2A-B are perspective views of the base housing of the embodiment depicted in FIG. 1 .

[0035] FIGS. 3A-B are perspective views of the shutter member of the embodiment depicted in FIG. 1 .

[0036] FIGS. 4A-D are various perspective, top, and bottom views of the door member of the embodiment depicted in FIG. 1 .

[0037] FIG. 5 is perspective view of an assembled of an exemplary 15-Amp tamper resistant receptacle sub-assembly according to various embodiments disclosed herein.

[0038] FIG. 6 is cross-sectional view of the assembled sub-assembly of FIG. 5 in the ready position.

[0039] FIG. 7 is a cross-sectional view of the sub-assembly showing the location of the electrical terminals of the device and the hot and neutral blade entry points into the sub-assembly.

[0040] FIG. 8 is a cross-sectional view showing the tamper resistant feature of the assembled sub-assembly when an object attempts entry in only the hot blade opening.

[0041] FIG. 9 is a cross-sectional view showing the tamper resistant feature of the assembled sub-assembly when an object attempts entry in only the neutral blade opening.

[0042] FIGS. 10A-D are cross-sectional views of the sub-assembly during the stages of plug insertion causing cooperating movement of the shutter and door.

[0043] FIG. 1 1 is cross-sectional view showing the resetting of the device to the ready position upon plug removal.

[0044] FIG. 12 is a cross-sectional view showing the tamper resistant feature in operation when an object is attempted to be inserted at an angle in the neutral opening.

[0045] FIG. 13 is an exploded view of the constituent parts of an exemplary 20-Amp tamper resistant receptacle sub-assembly according to various embodiments disclosed herein.

[0046] FIGS. 14A-C are perspective views of the base housing of the embodiment depicted in FIG. 1 .

[0047] FIGS. 15A-D are perspective views of the shutter member of the embodiment depicted in FIG. 1 .

[0048] FIGS. 16A-E are various perspective, top, and bottom views of the door member of the embodiment depicted in FIG. 1 .

[0049] FIG. 17 is perspective view of an assembled of an exemplary 20-Amp tamper resistant receptacle sub-assembly according to various embodiments disclosed herein.

[0050] FIG. 18 is cross-sectional view of the assembled sub-assembly of FIG. 17 in the ready position and showing the location of the electrical terminals of the device and the hot and neutral blade entry points into the sub-assembly.

[0051] FIG. 19 is a cross-sectional view showing the tamper resistant feature of the assembled sub-assembly when an object attempts entry in only the neutral blade opening.

[0052] FIG. 20 is a cross-sectional view showing the tamper resistant feature of the assembled sub-assembly when an object attempts entry in only the hot blade opening.

[0053] FIGS. 21 A-D are cross-sectional views of the sub-assembly during the stages of plug insertion causing cooperating movement of the shutter and door.

[0054] FIG. 22 is a close-up perspective view of the cam teeth and cam heads of the device during the plug insertion process.

[0055] FIGS. 23A-C are cross-sectional views showing the resetting of the device to the ready position during the extraction of the electrical plug blades.

[0056] FIG. 24 is a cross-sectional view of the tamper resistant feature during attempted insertion of an object at an angle in the neutral blade opening.

[0057] FIG. 25 is a close-up view of the protruding tab of the housing and its position relative to the door and shutter members.

[0058] FIG. 26A-C are various cutaway and partial cross-sectional views showing the tamper resistant feature during attempted insertion of a small objected at an angle in the neutral blade opening.DETAILED DESCRIPTIONS

[0059] The Figures depict presently preferred embodiments of a tamper-resistant receptacle sub-assembly for use in a 15-Amp (FIGS. 1 -12) or 20-Amp (FIGS. 13-25) TR receptacle. As depicted in the embodiment in the Figures, the tamper-resistant subassembly can be configured for use with a 15-Amp and / or 20-Amp receptacle and adapted for receipt of a two-prong or three-prong plug member. However, one of ordinary skill in the art armed with the present specification will readily appreciate that the teachings of the present disclosure may be adapted for any specific type of TR device through routine experimentation, including duplex receptacles, electrical cords, receptacles with USB ports, receptacles with circular or other geometries for the face or prongs, etc.

[0060] Turning back to the Figures. In FIGS. 1 -12, a 15-Amp TR receptacle (not shown) that may be equipped with a tamper-resistant receptacle sub-assembly 10 is shown. In this embodiment, the sub-assembly 10 is positioned beneath the hot and neutral openings in the TR faceplate to prevent unwanted access to the electrical terminals of the outlet. In the exemplary embodiment in FIGS. 1 -12, the sub-assembly 10 comprises a base housing 100, a shutter 200, a door 300, and a spring member 400. As best shown in FIGS. 5-6, the shutter 200, door 300, and spring 400 are disposed in the base housing 100. The base 100 includes a plastic body 101 having a generally planar bottom surface 102, an open top 103, a continuous upwardly extending sidewall 104 surrounding the bottom surface terminating at the open top 103.

[0061] In some forms, as best shown in FIGS. 2A-2B, the bottom surface 102 is generally rectangular and includes on a first, or neutral end 105A, an elongated lateral opening 106 to allow access to the neutral contact terminal of the TR receptacle; and on a second, or hot end 105B, both a shorter elongated lateral opening 107 to allow access to the hot terminal of the TR receptacle and a perpendicular opening 108 positioned beneath an upper protruding tab or finger extension 109 extending inwardly from the top edge 103 of a central portion of the sidewall 104 on the hot end 105B of the body 101 .

[0062] The bottom surface 102 of the housing body 101 also defines raised ramp members 1 10A, 110B associated with respective sidewalls 104A, 104B of the body 101 . The raised ramp members 110A, 110B each define a pivot pin cradle 11 1 A, 11 1 B and a ramp incline surface 1 12A, 1 12B. Disposed centrally in an area generally between the ramp members 1 10A, 1 10B is a raised central spring seat 113 sized to accommodate spring member 400 extending towards the hot end 105B of the body 101 . Formed in the backwall of the neutral end 105A is an internal blocking shoulder 114.

[0063] The top edge of the open top 103 also defines a pair of door member pivot pin cradles 115A, 115B on opposite sides of the housing body 101 towards the hot end 105B, and a pair of shutter locking tabs 1 16A, 1 16B on opposite sides of the housing body 101 towards the neutral end 105A of the housing body 101 .

[0064] The various features of the housing body 101 described above are preferably formed as part of a single piece molding for ease of construction, reduction of materials, savings on labor costs, and elimination of parts and points of failure. However, one ofordinary skill in the art will readily understand that any configuration or assembly of separate features to carry out the tamper resistant functions of the device are to be understood to be equally within the scope of the present disclosure.

[0065] In some forms, such as depicted in FIGS. 3A-B, the shutter 200 is sized to fit just below the open top 103 of the housing 101 on the neutral end 105A of the housing 101. The shutter 200 is preferably a single molded piece, and in the depicted form, comprises an upper shutter end 201 and a lower cam end 202. Extending between the upper end 201 and lower end 202 are left and right arms 203A, 203B which define an interior opening 204. The interior opening is sized to allow clearance of a plug blade as well as the spring seat 1 13 of the housing body 101 .

[0066] The upper shutter end 201 has a blocking surface 205 terminating in an angle end 206 and defining a pair of locking tab recesses 207A, 207B sized to allow the locking tabs 1 16A, 1 16B of the housing body 101 to hold the shutter 200 in place as part of the tamper resistant protection. The shutter blocking surface 205 is sized and positioned to block access from the neutral opening of the receptacle and preventing access to the neutral terminal contact of the device seated beneath the neutral opening 106. Extending laterally from the internal end of the blocking surface 205 is a central flange 208 having a spring seat 209 sized for the back end of the spring member 400. With this configuration, the spring member 400 is positioned on a first end 401 on the spring seat 209 of the central flange 208 and on a second end 402 on the spring seat 1 13 of the raised spring flange of the housing body 101 .

[0067] Each arm 203A, 203B defines on its underside in an upper area a rocking pin 210A, 210B sized to sit in the pin cradles 11 1 A, 11 1 B of the ramp member 1 10A. 110B. The arms 203A, 203B terminate at the lower end portion 202 of the shutter 200. The lower end portion 202 includes a raised cam platform 215 having a door pin cradle 220 and a cam head 225 for cooperating with door member 300.

[0068] As shown in FIGS. 4A-D, the door member 300 in turn, sits in the pin cradle 220 on the hot end 105B of housing body 101 and is supported by the door pin notches 1 15A, 1 15B defined in the upper edge of the open top 103. The door member 300 is positioned away from the protruding tab 109 of the housing 101 and situated to providecoverage over the hot terminal contact opening 107 and block access from the hot blade opening of the receptacle.

[0069] In some forms, the door 300 includes a blocking surface 301 laterally extending from a roller body axle 302. The axle 302 terminates on each end with a pin member 303A, 303B that cooperatively pivots in the door pin notches 115A, 115B of the body 101 . The underside of the door blocking platform surface 301 includes a cam tooth 305 that extends a distance to engage the cam head 225 of the shutter 200.

[0070] Once fully assembled, as best understood in connection with the Figures, the TR sub-assembly 10 is sized and configured to sit below the hot and neutral plug openings in the face of a TR receptacle. Once assembled and included as part of a TR receptacle, the shutter 200 is locked in place via the locking tabs 1 16A, 1 16B of the housing 101 and spring biased by spring 400 towards the neutral end 105A of the housing 101. In this position, the rocking pins 210A, 210B sit in the pin cradles 1 1 1 A, 11 1 B atop the ramp members 110A, 110B of the housing body. The door 300, in turn, pivotally rests via pins 303A, 303B seated in pin notches 1 15A, 115B of the housing 101 and axle body 302 in the cradle 220 of cam platform 215 of the shutter 200. The shutter 200 in this position blocks the neutral blade opening in the faceplate of the TR receptacle and the door 300 blocks the hot blade opening in the faceplate. In order to access the terminal contacts, simultaneous pressure from both the hot and neutral blade of an electrical plug must be applied.

[0071] Specifically, in the ready position just described, if a user attempts to insert an object into only hot blade opening of the TR receptacle as depicted in FIG. 8, the downward pressure will push against the blocking surface 301 of the door 300. As the door 300 attempts to rotate downwards by pivoting in the notches and / or cradle, the cam tooth 305 attempts to pull against the cam head 225 of the shutter 200 to overcome the spring bias of the spring member 400 and pull the shutter 200 towards the hot end 105B of the housing body 101 while simultaneously pivoting the shutter 200 about its rocking pins 210A, 210B. The locking tabs 116A, 1 16B seated in the locking notches 207A, 207B prevent any movement against the spring 400 as the shutter 200 is locked in place since the locking tabs cannot be cleared. Thus, continued force from the hot opening against the door 300 will not provide access as the cam platform 215 serves as a physical stopfrom further rotation towards the open position and the pivoting of the shutter 200 only serves keeps the locking tabs 1 16A, 1 16B in place and both blade openings of the TR receptacle remain blocked.

[0072] Similarly, when a user attempts to insert an object into only the neutral blade opening of the TR receptacle as depicted in FIG. 9, the downward pressure will push against blocking surface 205 and attempt to unseat the shutter from the locking tabs 1 16A, 116B. The downward pressure forces the shutter to pivot via its rocking pins 210A, 210B until the pivoting tips the lower end 202 of the shutter 200 into sealing contact with the door 300 preventing any further rotation or downward tipping of the upper end 201 of the shutter 200. In no event could the shutter pivot enough to allow any object or the shutter itself from clearing the internal blocking shoulder 114 of the housing 101 absent compression of spring member 400 and lateral movement of the shutter 200.

[0073] Even if an object is inserted in the neutral opening at an angle as shown in FIG. 12, the rotation of the shutter and the positioning of the protruding tab 109 prevent any clearance for an object to enter the neutral (or hot) opening and the electrical terminals of the device.

[0074] Only simultaneous pressure, typically via the insertion of both the hot and neutral blades of an electrical plug, will allow the electrical terminals to be accessible as shown in FIGS. 10A-D. As shown, as the blocking surface 205 and blocking surface 301 of the shutter 200 and door 300 are contacted by the plug blades, the simultaneous downward force will unlatch the shutter 200 from the locking tabs 116A, 1 16B as the cam tooth 305 simultaneously pulls against cam head 225 to begin compressing spring member 400. Continued simultaneous downward force will allow the door 300 to rotate further and cam the shutter 200 towards the hot end 105B of the device further overcoming the bias of spring member 400. The plug blades continue to travel into the housing body 101 through the plug openings which forces door 300 to pivot fully open which compresses spring 400 enough to provide clearance for the neutral blade to pass the angled end 206 of the shutter 200 and have access to the neutral terminal through neutral opening 106 while also allowing the door to pivot fully out of the way of hot blade and the opening 204 in shutter providing access to the hot terminal through the hot opening 107.

[0075] Upon retraction of the plug as shown in FIG. 11 , once the plugs are retracted, the bias of spring 400 will snap the shutter 200 back towards the neutral end 105A of the housing 100 and the cam platform 215 resets door 300 into the ready position while the shutter 200 resets in the locking tabs 1 16A, 116B providing tamper resistant protection until the next plug insertion.

[0076] A 20-Amp TR receptacle (not shown) may also be equipped with a tamperresistant receptacle sub-assembly 60 beneath the hot and neutral openings in the TR faceplate to prevent unwanted access to the electrical terminals of the outlet. In the exemplary embodiment in FIGS. 13-25, the sub-assembly 60 is differently configured but also comprises four pieces including a base housing 600, a shutter 700, a door 800, and a spring member 900. As best shown in FIGS. 17-18, the shutter 700, door 800, and spring 900 are operatively disposed in the base housing 600.

[0077] In some forms for a 20-Amp device, the base housing 600 includes a plastic body 601 having a generally planar bottom surface 602, an open top 603, a continuous upwardly extending sidewall 604 surrounding the bottom surface and terminating at the open top 603.

[0078] In some forms, as best shown in FIGS. 14A-C, the bottom surface 602 is generally rectangular and includes on a first, or neutral end 605A, a T-shaped lateral opening 606 to allow access to the neutral contact terminal of the TR receptacle; and on a second, or hot end 605B, a wider T-shaped opening 607 to allow access to the hot terminal of the TR receptacle.

[0079] The body 601 also includes a spring slot 608 and a spring seat 609 on a first lateral side 604A. On an opposite second lateral side 604B, the body 601 defines a raised ramp 610 having an apex pivot point 61 1 leading to a declining slope area 612 that ends with a raised flat run portion 613. Running parallel with the ramp 610 on the second lateral side 604B is a guide slot or guide track 614 stretching across a portion of the bottom planar surface 602.

[0080] The body 601 further includes door pin notches 615A, 615B and shutter locking tabs 616A, 616B similar to the 15-Amp embodiment described above. However, this embodiment includes door blocking tabs 617A, 617B positioned in front of the door pin notches. In addition, as depicted, this embodiment includes a raised T-shaped profilemount 618 positioned in front of the hot opening 607 in the planar bottom 602. Formed in the backwall of the neutral end 605A is an internal blocking shoulder 619.

[0081] The body 601 also includes declining slope area 622A and 622B raised at the T-shape slot 606 formed an internal blocking shoulder 623 at the end of 20A neutral slot.

[0082] The various features of the housing body 601 described above are preferably formed as part of a single piece molding for ease of construction, reduction of materials, savings on labor costs, and elimination of parts and points of failure. However, one of ordinary skill in the art will readily understand that any configuration or assembly of separate features to carry out the tamper resistant functions of the device are to be understood to be equally within the scope of the present disclosure.

[0083] In some forms, such as depicted in FIGS. 15A-D, the shutter 700 is sized to fit just below the open top 603 of the housing 601 on the neutral end 605A of the housing 601. The shutter 600 is preferably a single molded piece, and in the depicted form, comprises an upper shutter end 701 and a lower cam end 702. Extending between the upper end 701 and lower end 702 are left and right arms 703A, 703B which define an interior opening 704. In some forms, the interior opening has a block pyramidal shape and is sized to allow clearance of a hot plug blade in the opening while also providing sufficient camming clearance for a neutral blade to clear the end of the shutter as described in more detail below.

[0084] The upper shutter end 701 has a blocking surface 705 and a pair of locking tab recesses 707A, 707B sized to allow the locking tabs 116A, 116B of the housing body 101 to hold the shutter 700 in place as part of the tamper resistant protection. Beneath the locking tab recesses are curved bumps 706A, 706B that served to reinforce the tab notches to ensure product life, but also serve as bearings to aid smooth and even movement of the shutter to prevent binding or uneven movement.

[0085] The shutter blocking surface 705 is sized and positioned to block access from the neutral opening of the receptacle and preventing access to the neutral terminal contact of the device seated beneath the T-shaped neutral opening 606. The underside of the proximal end of the upper portion 701 includes rocking axles or pins 710A, 710B designed to sit on the pivot point 611 of the main ramp 610 and the pivot point 621 of the spring-side ramp 620 of the housing body 601 .

[0086] The arms 703A, 703B are generally downward ramp-shaped members that extend to the lower end portion 702 of the shutter 700. The spring side arm 703A includes a spring seat post 709 for the side spring member 900. The main ramp side arm 703B defines a downwardly extending track post pin 708 sized to fit in the guide slot 614 of the housing 601. The guide slot and post pin, as well as the raised T-shaped protrusion of the planar surface 602 of the housing hinder binding or uneven movement of the shutter in the housing due to spring force being applied to only one side.

[0087] The lower end portion 702 also includes a first cam body 712, a pair of second cam bodies 713, and a pair of third cam bodies 714. The configuration and positioning of the various cam members will become clearer in connection with the discussion of the operation of the device in the paragraphs below. On opposite corners of the lower end are a pair of blocking feat 715A, 715B especially shaped and formed to fill the void adjacent the blocking tabs of the housing 601 .

[0088] In some forms, such as the 20-Amp embodiment depicted in FIGS. 16A-E, the door 800 includes a blocking surface 801 for blocking the hot blade opening of the TR receptacle faceplate and preventing access to the hot blade terminal beneath the hot blade opening 607. Behind and pivotable about is the roller axle body 802 terminating in left and right pins 803A, 803B that rest in the door pin notches 615A, 615B of the housing 601 . The door 800 may include pin stop flanges 804A, 804B as shown in the Figures to prevent over-rotation of the door. Additionally, the housing 601 includes blocking tabs 617A, 617B in front of the door flanges.

[0089] In some forms, the 20-Amp embodiment includes a cam teeth extension plate 805 that extends beyond the blocking surface 801 towards the neutral end 605A of the device. The extension plate 805 is sized to allow room for a first central cam tooth 806, a pair of second cam teeth 807 adjacent and behind the first cam tooth, and a pair of third cam teeth 808 adjacent and behind the second cam teeth. The cam teeth 806, 807, 808 are configured and sized for cooperatively camming engagement with the first 712, second 713, and third 714 cam protrusions of the shutter 700 as discussed below.

[0090] The door blocking surface 801 also includes small raised tabs 809A, 809B that are positioned to block the larger gap in 20-Amp receptacles in conjunction with the blocking feat and blocking tabs.

[0091] Once fully assembled, as best understood in connection with the Figures, the TR sub-assembly 60 is sized and configured to sit below the hot and neutral plug openings in the face of a 20-Amp TR receptacle. Once assembled and included as part of a 20-Amp TR receptacle, the shutter 700 is locked in place via the locking tabs 616A, 616B of the housing 601 and spring biased by spring 900 towards the neutral end 605A of the housing 601 . In this position, the rocking pins 710A, 710B sit at the apex of ramps 610, 620 of the housing body 601 . The door 800, in turn, pivotally rests via pins 803A, 803B seated in pin notches 615A, 615B of the housing 601 and behind door stops 617A, 617B. The shutter 700 in this position blocks the neutral blade opening in the faceplate of the 20-Amp TR receptacle and the door 800 blocks the hot blade opening in the faceplate. In order to access the terminal contacts, simultaneous pressure from both the hot and neutral blade of an electrical plug must be applied.

[0092] Specifically, in the ready position just described, if a user attempts to insert an object into only hot blade opening of the TR receptacle as depicted in FIG. 20, the downward pressure will push against the blocking surface 801 of the door 800. As the door 800 attempts to rotate downwards by pivoting in the notches 615A, 615B the cam tooth 305 attempts to pull against the first cam of the shutter 700 to overcome the spring bias of the spring member 900 and pull the shutter 700 towards the hot end 605B of the housing body 601 while simultaneously pivoting the shutter 700 about its rocking pins 710A, 710B. The locking tabs 616A, 616B seated in the locking recesses 707A, 707B prevent any movement against the spring 900 as the shutter 700 is locked in place since the locking tabs cannot be cleared. Thus, continued force from the hot opening against the door 800 will not provide access as the first cam tooth 712 serves as a physical stop from further rotation towards the open position and the pivoting of the shutter 700 only serves keeps the locking tabs 616A, 616B in place and both blade openings of the TR receptacle remain blocked.

[0093] Similarly, when a user attempts to insert an object into only the neutral blade opening of the TR receptacle as depicted in FIG. 19, the downward pressure will push against blocking surface 705 and attempt to unseat the shutter 700 from the locking tabs 616A, 616B. The downward pressure forces the shutter 700 to pivot via its rocking pins 710A, 710B until the pivoting tips the lower end 702 of the shutter 700 into sealing contactwith the door 800 preventing any further rotation or downward tipping of the upper end 701 of the shutter 700. In no event could the shutter 700 pivot enough to allow any object or the shutter 700 itself from clearing the internal blocking shoulder 614 of the housing 601 absent compression of spring member 900 and lateral movement of the shutter 700.

[0094] Even if an object is inserted in the neutral opening at an angle as shown in FIGS. 24-25, the rotation of the shutter and the positioning of the protruding tabs 617A, 617B prevent any clearance for an object to enter the hot opening and the hot terminal of the device and internal shoulder 619 prevent any object from having the clearance to reach the neutral terminal.

[0095] Even if a small object is inserted in the neutral opening at an angle as shown in FIGS.26A to 26C, the declining slope area 622A and 622B will block or slip the small object away from reaching the underneath electrical contact.

[0096] Only simultaneous pressure, typically via the insertion of both the hot and neutral blades of an electrical plug, will allow the electrical terminals to be accessible as shown in FIGS. 21 A-D. As shown, as the blocking surface 705 and blocking surface 801 of the shutter 700 and door 800 are contacted by the plug blades, the simultaneous downward force will unlatch the shutter 700 from the locking tabs 616A, 616B as the first cam tooth 806 simultaneously pulls against first cam head 712 to begin compressing spring member 900. Continued simultaneous downward force will allow the door 800 to rotate further and cam the shutter 700 towards the hot end 105B of the device as second cam teeth 807 engage the second cam heads 713 further overcoming the bias of spring member 900. The guide pin and track slot opposite the spring, as well as the raised T- shaped member and other relief features that may be deployed, aid in the smooth and even sliding of the shutter in the housing body. Given that the spring is only on one side of the device and the shutter has to travel relatively further, the device is designed to hinder binding or unequal or uneven lateral movement of the shutter.

[0097] Returning to the Figures, in order to fully clear and provide access to the T- shaped neutral opening of the device, the third set of cam teeth 808 engage the third cam heads 714 and pull the shutter 700 a distance sufficient to allow the plug blades to enter the device, whereby the neutral blade will engage the end of the shutter and push it to the left as it passes and continues to the T-shaped opening and the hot blade passesthrough the internal opening of the shutter 700 after fully pivoting the door 800 and continues through the hot terminal opening 607. The plug blades reach the terminals, and the device is plugged in.

[0098] Upon retraction of the plug, as shown in FIGS. 23A-C, once the plug blades are retracted, the bias of spring 900 will snap the shutter 700 back towards the neutral end 605A of the base housing 600 and the cooperating cam teeth and heads reset door 800 into the ready position while the shutter 700 resets in the locking tabs 616A, 616B providing tamper resistant protection until the next plug insertion.

[0099] The above embodiments and similar embodiments use few parts and are thus easy and cost effective to build. Fewer parts also increase the useful life of the products as there are fewer points of failure. Fewer parts and simple mechanical interaction also increase the lifespan of the products. All of these benefits help to encourage and increase the use, availability, and reliability of these important safety products.

[0100] One of ordinary skill will appreciate that the exact dimensions and materials are not critical to the disclosure and all suitable variations should be deemed to be within the scope of the disclosure if deemed suitable for carrying out the objects of the disclosure.

[0101] One of ordinary skill in the art will also readily appreciate that it is well within the ability of the ordinarily skilled artisan to modify one or more of the constituent parts for carrying out the various embodiments of the disclosure. Once armed with the present specification, routine experimentation is all that is needed to determine adjustments and modifications that will carry out the present disclosure.

[0102] The above embodiments are for illustrative purposes and are not intended to limit the scope of the disclosure or the adaptation of the features described herein. Those skilled in the art will also appreciate that various adaptations and modifications of the above-described preferred embodiments can be configured without departing from the scope and spirit of the disclosure. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

CLAIMSWhat is claimed is:1 . A tamper-resistant receptacle sub-assembly comprising: a base having at least one ramp member and at least one locking tab; a shutter disposed in said base and pivotable and movable relative to said ramp member, said shutter locked in a ready position by said locking tab and said shutter including a cradle and cam head; a door pivotably disposed in said base and said cradle and locked in a ready position by said cam head biasing the door in a horizontal position, said door including a cam tooth; and a spring member disposed in said base and biasing said shutter in the ready position; whereby only simultaneous contact force with said shutter and said door allows said shutter to unlatch from the at least one locking tab and allows said door to pivot vertically thereby camming against the cam head and overcoming the spring bias of the spring member via the contact force to move the shutter down said at least one ramp members.

2. The tamper-resistant receptacle sub-assembly of claim 1 , wherein said base defines a pair of door pin notches.

3. The tamper-resistant receptacle sub-assembly of claim 2, wherein said base includes a protruding tab positioned behind said door.

4. The tamper-resistant receptacle sub-assembly of any one of claims 1 to 3, wherein said base includes a spring seat.

5. The tamper-resistant receptacle sub-assembly of any one of claims 1 to 4, wherein said shutter includes an upper end, a lower end, and a pair of arms connecting said upper end to said lower end and defining an interior opening.

6. The tamper-resistant receptacle sub-assembly of claim 5, wherein said shutter includes a flange member having a spring seat and said spring member is disposed in said interior opening and fixed on a first end at the spring seat.

7. The tamper-resistant receptacle sub-assembly of any one of claims 1 to 6, wherein said shutter includes at least one rocking pin for contacting said at least one ramp members.

8. The tamper-resistant receptacle sub-assembly of any one of claims 1 to 7, wherein said door includes a roller axle on a back end and a blocking surface on a front end.

9. The tamper-resistant receptacle sub-assembly of claim 8, wherein an underside of said blocking surface includes said cam tooth.

10. The tamper-resistant receptacle sub-assembly of any one of claims 1 to 9, wherein a force applied to only a shutter side will fail to unlatch the shutter the locking tabs and force applied to only a door side will fail to rotate the door in a vertical position.1 1. A 20-Amp tamper-resistant receptacle sub-assembly comprising: a base having at least one ramp member and at least one locking tab; a shutter disposed in said base and pivotable and movable relative to said ramp member, said shutter locked in a ready position by said locking tab and said shutter including at least first and second cam heads; a door pivotably disposed in said base and locked in a ready position by said shutter biasing the door in a horizontal position, said door including at least first and second cam teeth; and a spring member disposed in said base and biasing said shutter in the ready position;whereby only simultaneous contact force with said shutter and said door allows said shutter to unlatch from the at least one locking tab and allows said door to pivot vertically thereby camming against the first cam head and overcoming the spring bias of the spring member via the contact force to move the shutter down and allow the door to rotate to engage the second cam head of said shutter to overcome the bias of spring member and move said shutter and door to an open position.

12. The 20-Amp tamper-resistant receptacle sub-assembly of claim 1 1 , wherein said shutter includes a third cam head and said door includes a third cam tooth.

13. The 20-Amp tamper-resistant receptacle sub-assembly of claim 12, wherein said a base having at defines a spring opening and spring seat on a first side and an elongated ramp and guide slot on a second side.

14. The 20-Amp tamper-resistant receptacle sub-assembly of claim 13, wherein said shutter includes a spring seat post for said spring member on a first side and a guidepost pin on a second side configured to travel in said guide slot on a second side.

15. The 20-Amp tamper-resistant receptacle sub-assembly of claim 14, wherein said door comprises a roller axle on a first end, a blocking surface, and a cam tooth extension flap.

16. The 20-Amp tamper-resistant receptacle sub-assembly of claim 15, wherein said cam tooth extension flap includes a first main tooth, a pair of second cam teeth, and a pair of third cam teeth positioned for engagement with corresponding cam heads on said shutter.

17. The 20-Amp tamper-resistant receptacle sub-assembly of claim 15 or claim 16, wherein said cam teeth and said cam heads are positioned to allow downward movement of the extension flap to pull the shutter and overcome the bias of spring member and move the shutter down the ramp members.

18. The 20-Amp tamper-resistant receptacle sub-assembly of claim 17, wherein said guide slot and said guidepost pin hold the shutter in lateral position during spring compression.

19. The 20-Amp tamper-resistant receptacle sub-assembly of any one of claims 1 1 to 18, wherein a force applied to only a shutter side will fail to unlatch the shutter from the locking tabs and force applied to only a door side will fail to rotate the door in a vertical position.

20. The 20-Amp tamper-resistant receptacle sub-assembly of claim 19, wherein said base includes protruding tabs whereby an object inserted at an angle will fail to gain sufficient clearance to reach either electric terminal.21 . A tamper-resistant receptacle sub-assembly comprising: a base having a lower surface and a wall extending from the lower surface, wherein a ramp member is coupled to the lower surface and a locking tab is coupled to an upper edge of the wall; a shutter positioned at least partially within the base, wherein the shutter includes a cradle and a cam head; a door pivotably disposed in said cradle and locked in a ready position by said cam head biasing the door in a position parallel to the lower surface, said door including a cam tooth; and a spring member coupled between the base and the shutter; whereby only simultaneous contact force with said shutter and said door allows said shutter to unlatch from the locking tab and allows said door to pivot vertically thereby camming against the cam head and overcoming the spring bias of the spring member via the contact force to move the shutter down said ramp member.

22. The tamper-resistant receptacle sub-assembly of claim 21 , wherein said base defines a pair of door pin notches.

23. The tamper-resistant receptacle sub-assembly of claim 22, wherein said base includes a protruding tab positioned behind said door.

24. The tamper-resistant receptacle sub-assembly of any one of claims 21 to 23, wherein said base includes a spring seat.

25. The tamper-resistant receptacle sub-assembly of any one of claims 21 to 24, wherein said shutter includes an upper end, a lower end, and a pair of arms connecting said upper end to said lower end and defining an interior opening.

26. The tamper-resistant receptacle sub-assembly of claim 25, wherein said shutter includes a flange member having a spring seat and said spring member is disposed in said interior opening and fixed on a first end at the spring seat.

27. The tamper-resistant receptacle sub-assembly of any one of claims 21 to 26, wherein said shutter includes at least one rocking pin for contacting said ramp member.

28. The tamper-resistant receptacle sub-assembly of any one of claims 21 to 27, wherein said door includes a roller axle on a back end and a blocking surface on a front end.

29. The tamper-resistant receptacle sub-assembly of claim 28, wherein an underside of said blocking surface includes said cam tooth.

30. The tamper-resistant receptacle sub-assembly of any one of claims 21 to 29, wherein a force applied to only a shutter side will fail to unlatch the shutter the locking tabs and force applied to only a door side will fail to rotate the door in a vertical position.

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