Abstract:
A tamper-resistant outlet cover uses a spreadable grounding socket engageable post to secure the cover in place to thereby block access to an electrical receptacle, typically a wall outlet. The post is spread by insertion of a spreader, typically a threaded screw. The head of the screw is configured to only be engaged by a cooperatively shaped tool. Installation and removal of the cover is thus afforded only to one in possession of the tool.

Description:
FIELD OF THE INVENTION 
     The present invention is directed generally to a cover for an electrical outlet. More particularly, the present invention is directed to a tamper-resistant cover for an electrical wall outlet. Most specifically, the present invention is directed to a tamper-resistant outlet cover that requires the use of a cooperatively shaped tool to accomplish its installation and removal. The tamper-resistant outlet cover is positionable in a generally conventional electrical wall outlet that has two electrical plug blade receiving apertures and one electrical plug grounding prong or post receiving socket. The outlet cover utilizes a split and spreadable grounding prong or post, together with a grounding prong or post spreading element, to hold the cover in place. 
     BACKGROUND OF THE INVENTION 
     In a typical office environment, and particularly in a multi-person office environment, a plurality of computers are in use. Each computer, with its associated monitor and printer, is powered by electricity that is typically supplied from a conventional wall outlet. The usual wall outlet has two three apertured outlets that are defined by a suitable wall plate. Often, the computer and its associated peripherals will all be plugged into a surge protector whose purpose is to protect the equipment from damage resulting from possible power surges or current spikes. The surge protector is again connected to the convention wall outlet, typically by a short length of power cord. 
     Anyone who has been in a typical office will appreciate the havoc that is created by a loss of electrical power. Unless each computer is protected by some type of a back-up power supply, the loss of electricity, means that whatever is being worked on at the time of the loss of power will itself be lost. Despite the admonition to back up data on a frequent basis, such losses of data and work product are apt to be substantial. The result, in the instance of an electrical power failure, is loss of work product and loss of time. 
     Some electrical outages are beyond human control. The summer thunder storm, the failure of a transformer and the like are examples of unpredictable electrical failures that are a part of life. However, many potential power outages can be anticipated and precautions can be taken to avoid such outages. In many office buildings, especially in those buildings that are more than a few years old, the electrical wiring systems were not intended to accommodate the demands placed on them by the now common use of multiple computers. If the current load is overstepped, one or more circuit breakers will open. Such an occurrence will then require the services of maintenance personnel to re-set the breaker. Again, the result is a loss of data and a loss of productivity. 
     Often through trial and error, the capacity of an electrical distribution network in an office is determined. So long as that capacity is not exceeded, the office functions and the computers stay on. However, the addition of another electrical device, and particularly one which draws a substantial amount of current will upset the balance and trip the breakers. Vacuum cleaners operated by janitorial staff, space heaters used by cold employees in winter, fans used by the same employees in summer, and a multitude of coffee pots, water heaters and the like all can upset the balance. 
     In an effort to avoid circuit breaker openings, signs will be posted, memos will be circulated, and employees will be reminded, None of these efforts typically meet with long-term success. The memos are unread, the signs are unheeded and the discussions are forgotten. One employee plugs in a space heater or one janitor plugs in a vacuum cleaner or a floor scrubber. The result is the same, a loss of data and productivity as computers fail. 
     One effort to alleviate this problem has been the use of outlet covers. Every parent is familiar with the well-known child resistant outlet covers that have been employed to “child proof” a room or a home. These are typically plastic plates with a pair of wall outlet aperture engaging blades. While they are effective in preventing a small child from inserting an object into a wall outlet socket, they are easily removed by an adult. They do not provide a sufficient deterrent to an adult to accomplish the desired objective of preventing the connection of additional electrical equipment to a wall outlet. 
     It will thus be seen that a need exists for an outlet cover that is effective, efficient and easy to use. The tamper-resistant outlet cover in accordance with the present invention provides such a device that overcomes the limitations of the prior art. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an outlet cover. 
     Another object of the present invention is to provide a tamper-resistant outlet cover. 
     A further object of the present invention is to provide an outlet cover which is readily installed. 
     Still another object of the present invention is to provide an outlet cover which is securely attachable to a wall outlet socket. 
     Even yet a further object of the present invention is to provide a tamper-resistant outlet cover that is inexpensive and effective. 
     The tamper-resistant outlet cover in accordance with the present invention utilizes a pair of blades that are received in the two active sockets of a wall outlet. A generally cylindrical post is insertable into the grounding socket of the wall outlet. The two blades and the post are all connected to the rear face of a generally ovoid face plate. The entire cover is made of a non conductive material, such as plastic. The grounding socket engaging post has an axially extending central bore or aperture that is sized to receive a spreading element, typically a headed screw. As the screw is inserted into the post, it causes the post to increase in diameter. With the outlet cover positioned so that its blades and post are in the two active and the single grounding socket, respectively, the insertion of the spreading element into the grounding post acts to increase the diameter and thus the effective circumference of the post. This spreading of the post secures the post in place in the outlet&#39;s grounding socket. The head of the spreading element, such as a screw, is configured to be engageable only with a cooperatively shaped tool. This tool can have a number of suitable yet non-conventional shapes other than those of conventional screw drivers. 
     Once the tamper-resistant outlet cover has been put in place and the spreader element has been inserted, the outlet cover is difficult to remove, absent the use of the cooperatively configured tool. With the appropriately configured tool, the outlet cover is easily removed. The installed cover thus provides an effective deterrent to the unauthorized connection of extraneous electrical equipment, such as space heaters, fans, vacuum cleaners, floor scrubbers and buffers and the like while at the same time being quickly removable by authorized personnel. 
     The tamper-resistant outlet cover in accordance with the present invention is simple yet effective. It is quite easily and inexpensively fabricated. It requires a special tool for its use. However, that special tool is not expensive and is one that is likely to be available to authorized personnel. The use of the tamper-resistant outlet cover in accordance with the present invention dramatically reduces the incidence of circuit breaker openings and their resultant computer failure related problems. The tamper-resistant outlet cover of the present invention is an effective solution to the problem. It is a substantial advance in the art. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A full and complete understanding of the tamper-resistant outlet cover in accordance with the present invention may be had by referring to the following description of the preferred embodiments taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is an exploded perspective view of a first preferred embodiment of a tamper-resistant outlet cover in accordance with the present invention and showing the cover in cooperation with a wall outlet; 
     FIG. 2 is another exploded perspective view of the tamper-resistant outlet cover taken from the rear of the cover; 
     FIG. 3 is an assembled perspective view of the first preferred embodiment of the outlet cover showing the spreader partially inserted; 
     FIG. 4 is a cross-sectional side elevation view of the first preferred embodiment of the tamper-resistant outlet cover taken along line  4 — 4  of FIG. 2; 
     FIG. 5 is an exploded perspective view of a second preferred embodiment tamper-resistant outlet cover in accordance with the present invention; and 
     FIG. 6 is a cross-sectional side elevation view of the tamper-resistant outlet cover taken along line  6 — 6  of FIG.  5 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring initially to FIG. 1, there may be seen generally at  10  a first preferred embodiment of a tamper-resistant outlet cover in accordance with the present invention. Tamper-resistant outlet cover  10  is intended to be used to cover or to block one receptacle  12  of a typical electrical wall outlet, generally at  14 . As is well known, the typical wall outlet  14  includes a cover plate  16  that is secured to, and covers an electrical outlet box, which is not specifically depicted. The cover plate  16  typically provides two receptacles  12 , each of which has a pair of an active electrical plug blade receiving slots  18  as well as an electrical plug grounding prong or post receiving socket  20 . Such wall outlets  14  and receptacles  12  are well known and are of standard size and shape. 
     The tamper-resistant outlet cover  10 , as indicated previously, is sized and configured to block access to one receptacle  112  of the wall outlet  14 . It is clearly within the purview of the present invention to provide a cover plate that could block access to both receptacles  12  of a wall outlet  14 . However, it is typically more convenient to block or disable only one receptacle  12  at a time. 
     Tamper-resistant outlet cover  10  is preferably made of plastic or a similar non-conductive and deformable material. Cover  10  includes a cover plate, generally at  22 . This cover plate  22  includes a front face  24  and a rear face  26 , as seen more clearly in FIG.  2 . The cover plate  22  is sized to cover the receptacle  12  in the wall outlet  14  with which it will be used. As shown in FIGS. 1-3, the cover plate  22  is generally in the shape of a truncated oval. It will be understood that the exact shape of the cover plate  22  is selected so that it will adequately cover the receptacle  12  which it is intended to cooperate with. 
     A pair of active socket engaging blades  28  and  30  are connected, at their proximal ends, to the rear face  26  of the cover plate  22 . These blades  28  and  30  extend away from the cover plate&#39;s rear face  26  and are unsupported at their distal ends  32 ,  34 ; respectively. These blades  28  and  30  are sized to be receivable in the two active slots  18  of the receptacle  12  of the wall outlet  14 . Their distal ends  32  and  34 , respectively are preferably tapered to facilitate the insertion of the blades  28  and  30  into the two active slots  18  of the receptacle  12  of the wall outlet  14 . 
     A grounding socket engaging post, generally at  36  is also formed integral with, or is attached to the rear face  26  of the cover plate  22 . This grounding socket engaging post  36  is generally cylindrical and has a central, axially extending bore  38 . Bore  38  originates at the front face  24  of the cover plate  22  in a suitable chamfered cover aperture  40  and extends axially the length of the port  36 . As seen more clearly in FIGS. 2-4, post  36  is separated into two post segments  42  and  44 , each of which is generally semi-cylindrical in shape. Proximal ends of the two post segments  42  and  44  are joined to the rear face  26  of the cover plate  22 , as seen most clearly in FIG.  4 . Distal ends  46  and  48  of the two post segments  42  and  44  are not connected, in the first preferred embodiment of the tamper-resistant cover plate of the present invention, as may also be seen by referring to FIGS. 2-4. These two post segments  42  and  44  are formed by bifurcating the post  36  axially from its juncture with the rear face  24  of the cover plate  22  to the distal ends  46  and  48  of the post segments  42  and  44 . 
     A spreader, generally at  50 , is useable to spread apart the distal ends  46  and  48  of the two segments  42  and  44  of the grounding socket engaging post  36 , once the tamper-resistant outlet cover, generally at  10  has been inserted into the receptacle  12  of the wall outlet  14 . The spreader  50  is preferably a headed screw having a threaded shank  52  and a champered head  54 . Head  54  has a face  56  that is specially configured to cooperate with a complimentarily shaped tool, which is not specifically depicted. In the configuration shown in FIGS. 1 and 3, screw head face  56  has a pair of spaced bores  58 . It will be understood that these face bores  58  are sized and spaced to receive a pair of tips of a screwdriver-like tool. Only that tool, which is known in the art, but which is typically not possessed by an office worker or a janitor, will be able to turn the screw so that the threaded shank  52  of the screw or spreader  50  will travel along the axially extending bore  38  of the split post  36 . 
     In use, the tamper-resistant outlet, cover  10 , in accordance with the present invention, will be placed in a receptacle  12  of a wall outlet  14 , which receptacle  12  is to be blocked. The two blades  28  and  30  of the cover  10  are inserted into the active slots  18  of the receptacle  12  and the grounding socket engaging post  36  of cover  10  is placed into the grounding socket  20  of the receptacle  12 . Once this has been done, the spreader  50  is inserted into the bore  38  of the post  36  through the cover aperture  40 . The spreader is screwed into the post bore  38 . As spreader  50  travels axially along the bore  38 , it causes the two distal ends  46  and  48  of the post segments  42  and  44  to spread apart. Since the post segments  42  and  44  are constrained inside the grounding socket  20  of the receptacle  12 , the insertion of the spreader  50  will increase the effective circumference of the post  36 , to the extent possible in view of the constraints imposed by the diameter of the grounding socket  20 . This effects a positive securement of the post  36  in the socket  20  and thus a positive securement of the cover  10  over the receptacle  12 . It will be understood that the length of the shank  52  of the spreader  50  is selected so that the spreader  50  can be screwed fully into the axial bore  38  of the post  36 . The head  54  of the spreader  50  will be received in the champered cover aperture  40  with the face  56  of the spreader head  54  being flush with the front face  24  of the cover plate  22 . Removal of the tamper-resistant outlet cover  10  is easily accomplished by simply backing the spreader  50  out of the post bore  38 . This is again accomplished using the cooperatively shaped tool which is configured to engage the bores  58  or the other surface configuration of the spreader head  54 . 
     Turning now to FIGS. 5 and 6, there may be seen a second preferred embodiment of a tamper-resistant outlet cover in accordance with the present invention, generally at  60 . Cover  60  is generally the same in overall construction and operation as is the cover  10  discussed above. The same numerals will be used for corresponding elements in both embodiments. In the cover  60 , the grounding socket engaging post, generally at  62  is comprised of a generally cone-shaped or tapered segment  64  which is attached to the rear face  26  of the cover plate  22  of the outlet cover by an annular sleeve  66 . Both the cone-shaped segment  66  and the annular sleeves  66  have axially extending slots  68 . These slots  68  allow the sleeve  66  and the cone-shaped segment  66  to increase in diameter and circumference when the spreader  50  is inserted through the cover aperture  40 . The cone shape of the segment  64 , which defines a shoulder  70  where it joins the annular sleeve  66 , may, in some circumstances, provide an even more secure attachment of the outlet cover  60  to the wall receptacle  12 . It would also be possible to provide the cone-shaped segment  64  of the cover  60  as a truncated cone. In such a configuration, which is not specifically depicted, a distal position  72  of the cone-shaped segment  64  could be cut off. This would allow the distal ends of the now separate at least two cone-shaped segments, as defined by the axial slots  68 , to spread apart to a greater degree. Again, such spreading is limited by the diameter or circumference of the grounding socket  20  of the wall receptacle  12  into which the post  62  of the tamper-resistant outlet cover  60  is placed. 
     While preferred embodiments of a tamper-resistant outlet cover in accordance with the present invention have been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example the specific non-conductive material used to make the outlet cover, the overall size of the cover and the like can be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims.