US 3316523 A
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Description (OCR text may contain errors)
April 25, 1967 G. J. TRANGMAR ELECTRICAL CORD ACCESSORY Filed Nov. 20, 1964 3,316,523 ELECTRICAL CORD ACCESSORY George J. Trangmar, 418 S. Shaffer, Orange, Calif. 92666 Filed Nov. 20, 1964, Ser. No. 412,734 3 Claims. (Cl. 339-75) The present invention relates to an accessory for use in cooperation with an electrical plug of the type employed to temporarily establish electrical connection between a source ofpower and a utilization apparatus.
Electrically powered hand tools have now come into exceedingly widespread use. For example, in the construction industry, a vast number of electrically-powered hand saws are used by carpenters. Of course, in using electrical hand tools, they must be connected, as by a cord, to a source of electrical power. Conventionally, several lengths of cord, each terminating in a plug or terminal connector, are available for use with a hand tool. The user then interconnects the required number of these cords to permit use of the hand tool at the desired location.
One of the problems in using hand tools in the construction industry, and in related fields as well, is that the plugs or terminal structures tend to catch on virtually any obstacle with the result that the user must frequently stop working, trace the cord to the location where the plug is caught and free the plug for further movement. Of course, this operation is time consuming and annoying to the user of the electrical hand tool or other apparatus.
Another problem attendant the use of portable electrical hand tools is that the cord or power line frequently parts, thereby requiring repair. Most usually, the line separation involves simply a pair of plugs or junction terminals that have been pulled apart. However, not infrequently, the break occurs in the cord or power line, the most frequent instance of which is a break contiguous a plug.
As a result of these difficulties arising in the use of electrically powered hand tools, a need exists for an accesory which may be combined with an electrical plug and cord, in combination, to permit the use of these hand tools with greater effectiveness and convenience. Furthermore, the accessory of the present invention is also useful in cooperative combination with electrical plugs employed in conjunction with various other forms of electrical apparatus and equipment.
An object of the present invention is to provide an accessory for use in combination with an electrical plug and cord, which reinforces the plug and cord against separation, provides a smooth transitional surface between the plug and the cord to avoid the junctions from catching on various obstacles, and incorporates fastening means whereby pairs of the combination units may be locked together.
Another object of the present invention is to provide an accessory for use in combination with an electrical plug and cord, which accessory may be inexpensively manufactured, and effectively employed in conjunction with said plug and cord combination.
A further object of the present invention is to provide an improved junction in an electrical cord or transmission line utilized for connecting an electrical apparatus to a source of electrical energy.
These and other objects and advantages of the present invention will become apparent from a consideration of nited States Patent 3,316,523 Patented Apr. 25, 1967 the following, taken in conjunction with the drawing, wherein:
FIGURE 1 is a perspective view of a combination structure incorporating the present invention;
FIGURE 2 is a vertical sectional view taken along line 2-2 of FIGURE 1;
FIGURE 3 is a vertical sectional view taken along line 3-3 of FIGURE 1;
FIGURE 4 is a perspective view of a component of the combination structure of FIGURE 1;
FIGURE 5 is a sectional view of another form of accessory incorporating the principles of the present invention;
FIGURE 6 is a vertical sectional view taken along line 6-6 of FIGURE 5; and
FIGURE 7 is a perspective view of a component incorporated in the structure of FIGURE 5.
Referring initially to FIGURE 1, there is shown a flat cylindrical plug 10 as well known and widely used in conjunction with electrical hand tools. The plug 10 incorporates a set of electrical prongs 12 serving as junction terminals and friction fasteners. An electrical cord 14 incorporating individual conductors 16 is aflixed to the plug 10 with the conductors 16 electrically contacting the prongs 12. An accessory 18 constructed in accordance with the present invention is then cooperatively mated with the plug 10 and the cord 14 as a result of being fixed over the cord 14 contiguous the rear of the plug 10.
In function, the accessory 18 provides a conical configuration, the outside surface of which afiords a smooth contiguous surface between the plug 10 and the cord 14. As a result, the plug 10 may be easily pulled across various obstacles without catching thereon. Furthermore, the accessory 18 serves to reinforce the attachment between the plug 10 and the cord 14, as well as relieving the strain normally received by the cord 14 contiguous the plug 10.
Considering the structure of the present invention in greater detail, reference will now be had, somewhat simultaneously to FIGURES 1, 2, 3 and 4. The accessory 18 consists of two separate sections 20 and 22 (FIGURE 3) joined by a pair of self-threading screws 24 and 26;, set in recesses 28 and 36 in the section 20.
The two sections 20 and 22 mate to form the conical configuration of the accessory and also to define a particular interior cavity. That is, the sections 20 and 22 each contain interior chambers defining a coaxial passage through the accessory through which the cord 14 passes and further providing irregularities serving to fix the accessory to the plug 10. Specifically, a semi-cylindrical cavity 32 (FIGURE 4) enters the small end 34 (remote the plug 10) extending substantially half-way through the section. At the termination of the cavity 32, a larger semi-cylindrical cavity 36 is formed in each of the sections 20 and 22 provided to receive a flange clamp 38 (FIGURE 2) which is a portion of the plug it and serves to clamp the plug 10 to the cord 14. The cavity 36 is partially closed by a semi-annular end 40 (FIGURE 4) defining an opening 42.
In mating relationship, the sections 20 and 22 provide a passage defined by the cavities 32 which receives the cord 14. These cavities are lined by teeth 44 which bite into the cord 14 so that the strains applied to the cord 14 are transferred to the plug 10 through the accessory 18 rather than through the electrical junction between the .cord 14 and the plug 10.
Adjacent the passage defined by the cavities 34 in the accessory 18 is a larger chamber defined by the cavities 36 serving to contain the clamp 38. The ends 40 of the two sections 20 and 22 dwell in the space 48 between the clamp 38 and the plug 10 in the assembled configuration locking the accessory to the plug 10. Therefore, the accessory 18 is locked to the plug 10 by the ends 40 and to the cord 14 by the teeth 44.
The accessory structure as shown in FIGURES 1 through 4 may be best manufactured of insulating material, thereby avoiding exposed surfaces which may be energized by electrical potential. For example, the sections 20 and 22 may be molded of plastic, hard rubber, or various other similar materials. In this regard, the teeth 44 may be molded into the surface of the cavity 32 comprising the same material as the remainder of the section; or, alternatively, the teeth 44 may be provided in a. cylindrical metal liner or separately-embedded teeth may be used.
In using the accessory, it is a simple matter to bring the sections 20 and 22 into mating relationship locked over the clamp 38. Thereafter, the screws 24 and 26 are easily placed in the sections 20 and 22 fastening them together so that the accessory may be parted if desired at a later time. In this regard, the clamp 38 will normally be tightened by tightening the bolts 46 comprising a part thereof prior to applying the accessory 18. Thereafter, the accessory 18 provides shelter for the bolts 46 with the result that they are less likely to be loosened, in turn releasing the clamp 38.
In certain instances, a modified form of the accessory embodiment considered above will be found useful. One example of such a modified form will now be considered with reference to FIGURES 5, 6 and 7 wherein elements similar to those previously described carry identical reference numbers. FIGURE shows a male plug as previously considered matably engaged with a female plug 50 having an exterior configuration similar the plug 10. The plug 50 carries a clamp 52 incorporating bolts 54 for locking the plug 50 to a cord 56. As shown in FIGURE 5, the plugs 10 and 50 are both equipped with accessories 58 which units are locked together by a spring leaf 60 as shown in FIGURE 7. As a result,- the plugs 10 and 50 may not be easily separted without first releasing the spring leaf 60. Therefore, in pulling the cords 14 and 56 through and over various obstacles, the
' plugs 10 and 50 are not easily separated.
Considering the structure of FIGURE 5 in greater detail, the two accessories 58 as shown are identical in form, comprising an upper section 62 and a lower section 64 held together in mating relationship by a snap ring 66 positioned in an annular groove 68' about the sections 62 and 64. The mated sections 62 .and 64 define a concentric cylindrical passage 70 bearing teeth 72 which lock the accessory 58 to the cord lying in the passage 70.
The passage 70, adjacent the small end of the accessory 58 opens into a larger cavity 74 which is partially closed by the annular end 76 dwelling in the space 48 7 between the clamp of the plug and the plug proper to lock the accessory to the plug.
The cavity '74 is generally cylindrical and receives a large transverse bore 78 and a small rectangular-section transverse passage 80. The passages 80 carry the ends of the spring leaf 60 anchoring two plugs e.g. plugs '10 and 50 in mating relationship. The spring leaf '60 (FIG- URE 7) includes an elongate flat section 82 the ends 84 and 86 of which are turned substantially normal to the section 82. The terminations 88 and 90 of the ends 84 and 86 respectively, are again curved to provide locking flaps.
The accessories 58 as shown in FIGURES 5 and 6 may be formed of sections which are molded or otherwise formed of various insulating materials, e.g. plastics, or hard rubber. The spring leaf 60 may be formed by stamping or various other operations and will normally be made of metal e.g. beryllium copper or spring steel.
In assembling the structure as shown in FIGURE 5, the plugs 10 and 50 are first mated respectively to the cords 14 and 56. Thereafter, the bolts 46 and 54 are tightened thereby clamping the plugs onto their associated cords. Next, the sections 62 and 70 of the accessories 58 are mated over the plugs 10 and 50 along with the cords 14 and 56, and locked in position by placement of the snap rings 66, which structures are very well known in the prior art.
Next, the plugs 10 and 50 are matingly engaged and the spring leaf 60 is positioned with one end in each of the passages 80, so that the tabs 88 and extend along the interior of the cavity 74 locking the spring leaf in position to hold the plugs 10 and 50 in mating relationship.
In using the structural combination as illustrated in FIGURE 5, it can be appreciated that the provision of a smooth continuous surface between the cords 14 and 56 permits the junction therebetween to be pulled over various obstacles without being caught thereon. Furthermore, the interlocking relationship between the two accessories 58 preserves the plugs 10 and S0 mated together with relatively few occurrences of plug separations.
Still further, it is also apparent that mechanical stresses applied to the cords 14 and 56 are largely relieved by the accessories 58 rather than to be applied to the electrical junction. As a result, failure occurs less frequently.
At the conclusion of a particular job, it may be desired to separate the plugs 10 and 50 as shown in FIG- URE 5. To accomplish such separation, the operator inserts a finger through the bores 78 contacting one of the end tabs 88 or 90 urging it toward the plugs 10 and 50 so that it is released and may be withdrawn through the passage 80. As a result, the two plugs 10 and 50 are no longer locked together and may be easily disconnected. Of course, if it should be necessary to repair one of the plugs or otherwise gain access thereto, it is readily apparent that the accessories 58 are easily parted by simply removing the snap ring 68 by twisting the ends 92 thereof as shown in FIGURE 6.
As apparent from the above consideration, the structure of the present invention provides an advantageous accessory which may be simply and easily manufactured in large quantity, and which affords considerable convenience and time saving in the use of power tools supplied with electrical energy through extended lengths of electrical cord. Of course, other advantages and features of the present invention in addition to those apparent from the embodiment described herein will be readily understood and appreciated by persons skilled'in the art. Furthermore, various modifications of the embodiments shown and described herein will also be apparent. Therefore, the scope hereof shall not be determined by the disclosure set forth above, but rather by the claims appended hereto.
What is claimed is:
1. In combination:
a first electrical plug including a spaced-apart transversely-extending cord clamp defining an indentation;
a first electrical cord afiixed to said first electrical plug by said cord clamp;
a second electrical plug to mate with said first electrical plug, also including a spaced-apart transverselyextending cord clamp defining an indentation;
a second electrical cord affixed to said second electrical plug by said cord clamp;
first and second accessories for each of said first and second plugs, each of said accessories including;
first and second sections of insulating material 5 a 6 matable to define a conical exterior configurament with said accessories and accessible for release ration, said sections each further defining inbeneath the exterior configuration of said accessories. ternal chambers to receive said cord and internal extensions to matingly engage said plug References Cited y the Examine! inaaid indentatlion, by liocking1 engagement with 5 U D STATES PATENTS sai transverse y-exten rng c amp; an means for locking said first and second sections Nerf) 339-403 X White 229-63 In mating relationship affixed to said plug and 2 043 666 6/1936 Ki b 339 63 said cord whereby to provide a smoothly tapered 2841635 7/1958 iz I 339 75 transitional surface between said plug and said 10 3170749 2/1965 J 1 e I cord o anson et a 2. A combination according to claim 1 further com- FOREIGN PATENTS prising fastening means for locking said first and said second accessories together whereby to hold said first and 1,098,645 3/1955 Francesecond plugs matingly engaged. 15
3. A combination according to claim 2 wherein said EDWARD ALLEN Primary Examiner fastening means includes latching portions for engage- W. DONALD MILLER, Examiner.