Security Device for Electric Appliances

This invention relates to electrical appliance security devices, and more particularly to such devices which secure the appliance by capturing the plug.

Heretofore unauthorized use of expensive, delicate or dangerous electrical equipment and machinery has been prevented by traditional lock-and-key devices such as taught in United States Letter Patents:

U.S. Pat. No. 2,654,037 issued Sept. 29, 1953 to Katz,

U.S. Pat. No. 4,488,764 issued Dec. 18, 1984 to Pfenning,

U.S. Pat. No. 4,592,607 issued June 3, 1986 to Pejovie, and

U.S. Pat. No. 4,648,667 issued Mar. 10, 1987 to Baumgart.

The plug on the cord to the electrical equipment was placed in a strong, tamper proof container which was then closed and secured shut by a lock.

The key was available to authorized personnel only. Unauthorized personnel were unable to open the container, and were prevented from using the secured device unless they had possession of the key. Mere verbal permission from the authorized personnel was insufficient. The key had to be located and brought to the equipment location. Without keys, unauthorized personnel were unable to exercise discretion in emergencies or other unforeseeable situations.

A second disadvantage of these lock-and-key devices concerned the long lifetime of the lock mechanism. Over the years many extra keys were made, and unauthorized personnel eventually possessed unauthorized keys. The security of the lock-and-key devices became diluted.

U.S. Pat. No. 4,219,693 issued Aug. 26, 1980 to French teaches a security technique which discourages unauthorized use of electronic equipment; but does not physically prevent unauthorized use. The input cable to the electronic device was secured within a brittle plastic shell. The shell was formed by opposed halves which snap together around the cable to prevent use. The shell had to be broken and removed in order to install the cable and use the equipment. A missing shell, or pieces of a broken shell, indicated unauthorized use. The fear of post use detection discouraged tampering by unauthorized individuals.

It is therefore an object of this invention to provide an improved appliance security device for discouraging unauthorized use of secured appliances.

It is another object of this invention to provide such an appliance security device which may be easily installed over the appliance plug by hand without the use of tools.

It is further object of this invention to provide such an appliance security device which is difficult to remove from the appliance plug without a suitable cutting tool.

It is further object of this invention to provide such an appliance security device which is inexpensive.

It is further object of this invention to provide such an appliance security device which reveals unauthorized use of the appliance.

It is further object of this invention to provide such an appliance security device which prevents young children from accessing the secured electrical appliance.

It is further object of this invention to provide such an appliance security device which supports use discretion by an unauthorized user.

Briefly, these and other objects of the present invention are accomplished by providing an electrical appliance security device having an open condition and a closed condition for retaining the plug of an electrical cord. The device has a base for receiving the plug when the security device is in the open condition, and an opposed cover which cooperates with the base to form a plug retaining chamber when the security device is in the closed condition. A port permits the electrical cord to extend out of the chamber. A post and cap latch secures the base and cover together when the security device is in the closed condition. The post must be severed to permit the security device to open and release the cord.

Further objects and advantages of the appliance security device and the post use detection feature will become apparent from the following detailed description and drawing in which:

FIG. 1 is a perspective view of a general embodiment of an appliance security device shown in the open condition for receiving the appliance plug;

FIG. 2 is a perspective view of the appliance security device of FIG. 1 shown in the closed condition for securing the appliance plug;

FIG. 3 is a fragmentary view in section showing a locking post with a cutting groove defining the location of the sever between the post and the cap;

FIG. 4 is a perspective view of a releasably hinged embodiment of the appliance security device in which the cover member is removably hinged to the base member

FIG. 5 is a broken away view of a cutter for removing the post cap to release the appliance plug; and

FIG. 6 is a fractional view in section showing a locking aperture having a submerged perimeter.

Security device 10 has a lower or base closure member 12-B and an opposed upper or cover closure member 12-C hinged thereto at one end. Device 10 forms a closable "clam" like chamber 16 for receiving plug 18 (shown in dashed lines) of an electrical appliance to be secured. The plug is mounted within chamber 16 when security device 10 is in the open condition as shown in FIG. 1. Latching means such as twin locking posts 20 extend upward from base 12-B and engage twin locking apertures 22 in cover member 12C for holding the closure members together. The plug is secured within the chamber when the device is in the closed condition as shown in FIG. 2. Cord port means such as opposed notches 24-B and 24-C along the edge of the closure members 12-B and 12-C permit the cord of the appliance to extend out of the chamber. The notches are preferably located in the end of the security device opposite to the hinge.

The plug to be secured is placed in the chamber area of base 12-B with the cord resting in cord channel 25 between locking posts 20 and lower notch 24-B. Cover 12-C is pressed downward against base 12-B causing posts 20 to pass through locking holes 22. The posts have conical caps 26 slightly larger than locking holes 22, which self center into the holes. The resulting snap-lock of the peripheral portion of the caps past the edge of the holes prevents separation of the closure members. The closure is secured in the closed condition and plug 18 is unaccessible. Locking posts 20 are spaced to guide the cord toward lower notch 24-B, and position the plug properly within the chamber prior to closure.

In order to access the plug, the cone caps are sheared off using a suitable cutting edge (shown in dashed lines in FIG. 2) such as a blade, scissors or clippers. The locking posts are freed from the locking apertures, permitting the closure members to open releasing the plug from the chamber. The cutting instrument is guided by the top surface of the cover member, and does not penetrate the shell or enter the chamber. Damage to the insulation of the plug and cord is avoided.

In order to facilitate shearing the caps, the locking post may be provided with a cutting groove 30 immediately beneath the cap as shown in FIG. 3. The cutting groove defines the location of the cut and minimizing the effort required to execute the cut. The cutting edge slips into the crevice between the overhanging periphery of the cap and the surface of the top cover, and is directed into the cutting groove. The loss of material in the post due to the cutting groove does not affect the closing of the chamber which presents only a compressive load on the post.

Security device 10 does not physically prevent access to the plug, but severely discourages access due to the shame-guilt reaction of the tamperer who knows his access will be discovered. The missing caps are concrete evidence of unauthorized access. In unusual situations, unauthorized users may exercise user discretion, and open the chamber, access the plug and use the secured appliance. The security device is designed to prevent access to personal appliances such as TVs and PCs in noncritical situations. For dangerous electrical equipment such as power tools, conventional lock-and-key devices should be employed.

The security device may be color coded (and/or symbol coded) to prevent installation of an identical replacement device after unauthorized access. The remainder of the surface area on either shell is available for warnings and instructions. Authorized access to the secured appliance requires only verbal permission such as over a telephone, and a cutting instrument. Transfer of a key is not necessary.

A removable cover embodiment in which the cover closure member is removably hinged to the side of the base closure member is shown in FIG. 4. Cover 40-C has downward extending forward and rear edge flanges 42-F and 42-R extending along a side of major dimension. The flanges have hinge slots therein for engaging forward and rear curved hinge tabs 44-F and 44-R on base 40-B. In the open condition shown in FIG. 4, the cover is completely removed from the base permitting ready access to the plug chamber. To close the device, the hinge slots are engaged over tabs 44, and the cover is pivoted to close over the base.

Twin arrow posts 48 extending upwards from base 40-B engage twin locking slots 50 in cover 40-C for locking the cover in the closed position. The points of the arrows slip into the locking slots and snap-lock as the wider wing portion 48-W of the arrows pass through the slots.

The arrows also assist in retaining the cord in the cord channel between the securing posts during mounting of the plug. The cord is guided by the arrow heads and easily slips into the channel. The inside wings of the arrows trap the cord within the channel until the cover is closed thereover.

Cutting device 50 has a cutting blade 52 slideably mounted within a flat housing 54 for severing the caps from the locking posts. The cap to be severed is retained within cutting aperture 56, and blade plunger 58 is pushed forward into housing 54. Cutting blade 52 is connected to the plunger, and is displaced past the cutting aperture to sever the post cap. The cutting blade in cutter 50 is never exposed to the user during normal use.

Cutting device 60 has nosed shaped snipping blades 62 for entering a submerged perimeter region 64 around aperture 66 to snip off cap 68. Ordinary cutting blades cannot enter submerged perimeter region 64. This recessed cap embodiment is particularly difficult for children to open.

The follow particulars of the security device are given only as an illustrative example.

Overall dimensions of the security device

height 11/4 inches (3 cm)

width 11/2 inches (3.8 cm)

length 3 inches (7.6 cm).

Dimensions of the post, cap and aperture

post height with cap 11/2 (3.8 cm)

post diameter 1/8 inches (0.32 cm)

cap diameter 1/4 inches (0.64 cm)

aperture diameter 3/16 inches (0.48 cm).

The dimensions and material give above are not intended as defining the limitations of the invention. Numerous other applications and configurations are possible.

It will be apparent to those skilled in the art that the objects of this invention have been achieved by providing an improved appliance security device for discouraging unauthorized use of secured appliances as described hereinbefore. The security device which may be easily installed over the appliance plug by hand without the use of tools merely by placing the cord into the device and snapping the device shut. The device locks in the closed condition making it difficult to remove from the appliance plug without a suitable cutting tool. The missing caps reveals unauthorized use of the appliance. In addition young children are prevented from accessing the secured electrical appliance because they cannot sever the caps. Unauthorized discretion is possible because a key is not required.

Clearly various changes may be made in the structure and embodiments shown herein without departing from the concept of the invention. Further, features of the embodiments shown in the various Figures may be employed with the embodiments of the other Figures. Therefore, the scope of the invention is to be determined by the terminology of the following claims and the legal equivalents thereof.