US2063110A - Electrical appliance and plug therefor - Google Patents

Description

Dec. 8, 1936. w MCARDLE 2,063,110

ELECTRICAL APPLIANCE END PLUG THEREFOR Filed Sept. '7, 1934 Patented Dec. 8, 1936 UNITED STATES PATENT OFFICE ELECTRICAL APPLIANCE AND iLUG THEREFOR Application September 7, 1934, Serial No. 743,078

6 Claims.

This invention relates to connector plugs for electric appliances, and while the invention is of general application to plugs for electrical household appliances, the invention is herein shown and described for purposes of illustration in connection with an electric sadiron.

Electric current is supplied to the conventional electric sadiron and similar household appliances through a flexible cord attached thereto and this point of attachment has always given a considerable amount of trouble. However, when the irons were of low capacity, the trouble was not particularly diificult but with the advent of high capacity irons drawing in the region of a thousand watts, the difficulty is much more serious. In the past, the iron has been provided with a pair of contact terminals projecting from the body of the iron and adapted to be received in a connector plug carried on one end of the cord, the plug being capable of withdrawal from the terminals to separate the cord from the iron. However, when the plug is removed from the terminals there is a considerable amount of arcing between the terminals and the contact elements of the plug. This causes pitting and corroding of the terminal posts and of the contact elements so that in a short time the parts are not capable of making an effective contact. As above mentioned, when the wattage of the irons was low this trouble was not particularly diflicult but with the increased wattage in 1000 watt irons the arcing is much more severe and the pitting andcorroding is increased.

Another source of difficulty to this type of connection between the cord and the iron lies in the fact that the terminal posts are received in sockets of the plug formed by bronze contacts, the bronze contacts being used to secure proper conductivity. These contacts cannot be tempered and hardened as would be the case with spring steel and, consequently, when the plug is pushed over the terminal posts the bronze contacts spread apart and do not again come together so as to grip the terminal posts tightly. As a result, a certain amount of arcing normally occurs during the useof the iron. This is further aggravated by the fact that the plug is then loosely held on the terminal posts which allows a certain amount of movement of the plug as the iron is moved about. It augments the arcing and further increases the difiiculty from corroslon and from pitting.

The cord cannot be satisfactorily connected directly to the iron, that is, to the terminal posts of the iron because the heat of the iron is then conducted into the cord, causing the insulation to be burned or otherwise depreciated to a point where the two cables of the cord come into contact or in such proximity that the cord becomes burned off or shorted.

With the above mentioned objections in view, I havev aimed to provide a connector plug for connecting the cord to the appliance in such manner that the contact elements of the plug at all times firmly grip the terminal posts.

A further object of the invention is to provide a plug carrying means for normally securing the plug to the appliance to prevent frequent removal of the plug.

Another object of the invention is to provide a plug structure having means for preventing a considerable amount of the heat from the appliance from passing to the plug and thereby heating both the plug and the cord attached thereto.

Another object of the invention is to provide aplug having means for holding the same against movement with respect to the terminal .a plug having means for normally securing the plug on the iron against movement with respect to the terminal posts, the means being accessible for removal of the plug as required.

Another object of the invention is to provide a plug of generally improved design and function.

Other objects and attendant advantages will become apparent to those skilled in the art from the following description and the accompanying drawing, in which- Fig. 1 is a side elevation partly in section;

Fig. 2 is a fragmentary rear elevation;

Fig. 3 is a section or. the line 3-3 of Fig. 2, and

. Fig. 4 is asection on the line 44 of Fig. 2.

The invention contemplates a plug of insulating material provided with meansfor spacing the end of the plug from the body of the appliance and means for holding the plug in fixed position with respect to the appliance, together with spring means for holding the contact elements or plug jacks in firm contact with the terminal posts of the appliance.

Referring to Figure 1, I have shown the invention in connection with a conventional electric sadiron having a body 6, a handle I secured thereto by means of handle straps 8 and 9, the handle being secured to the handle straps by means of a bolt H, a temperature controlled lever l2 mounted on the'body, and a heel rest tion of a cord plug.

I3 having a rectangular sleeve M for the recep- The plug includes two insulating members l5 and I6 complementarily shaped and positioned face to face to form a'plug body. The member I6 carriesa pin I1 receivable in an opening l3 of the member I5 to-locate the two portions with respect to each other. The bodyihasa pairof sockets l9 and 2| for the reception of jacks22 and 23 presently to be described, the socketsbew ing formed by recesses inthe adjoining faces of contact elements are placed face to face so as to provide a more or less cylindrical surface for v the reception of the terminal posts for maximum surface area therebetween. The upper ends of the contact elements 21 and 28 are secured together by means of a screw 34 which also serves. for the attachment of the individual cables 35 and 36 of'the cord 26. The jacks 22 and 23 are of such size that the contact elements 21 and 23 7 come substantially into contact when the in su lating portions l5 and I6 are in surface contact and have somewhat smaller inside diametersthan the outside diameters of the terminalposts 32 and, V

33 so that when the terminal posts enter the jacks the contact elements 21 and 28 are spread as well as the insulating portions l5 and I6 of the body;

Pressure is applied between the, jacks and the terminal posts by means of springs 31 and 38 which span the edges of the plug adjacent the lower end thereof, as best shown in Fig. 4. The springs are positioned in recesses 39 and 4| in the outer surface of the plug whereby to hold'the portions of the plug together without bolts or screws and maintain the portions in registering relationship. move into the jacks, the contact elements 21 and 28 are spread, causing the plug to spread against the tension of the springs 31 and 38 whereby the springs urge the contact elements into gripping contact with the terminal posts.

The springs 31 and 38 each carry a depending finger extendingbeyond the end of the plug, as shown at 42 and43,"the fingers being adapted to abut the body of the sadiron, as shown in Figure 1, to space the lower end of the plug from the body of the iron. This structure permits air to circulate between the end-of the plug and the body of the iron, the air circulating around the terminal posts and serving to cool the same so that only a limited portion of the heat of the iron is transmitted upward along the terminal posts and, as a result, the plug is maintained at a relatively low temperature.

- The two insulating halves of the plug body are held together at their upper ends by means of a collar 44 shaped to be received in an annular recess 45 at the upper'end of the body. This collar prevents the two halves of the plug body from spreading at the top but permits the bottom end to spread, as previously described. The collar 44 has a-bracket 46 extending upwardly and outwardly so as to register with the end of the handle 1 and is provided with an opening 41 for the reception of the bolt I I so that the bracket is fixedly attached to the handle 1 and the handle Thus, when the terminal posts strap 9. The bracket and collar are so shaped as to apply a slight downwardpressure on the top of the plug body urging the fingers 42 and 43 intofcontact with the body of the iron, whereby to'fixedly secure the plug on the iron and prevent any tilting or weaving movement of the plug with respect to the iron. In this way, repeated withdrawals of the plug from the iron are prevented, the plug being attached in a semi-permanent manner to the iron. In service, this requires the operator to disconnect the iron from the source of current supply at the opposite end of the cord26, leaving the plug in position on the iron. However, when necessary, the plug may be easily and conveniently removed from the iron by loosening the bolt II and withdrawing the plug from the terminal posts in the usual manner.

While the advantages of my improved construction will doubtless be apparent, I desire to direct particular attention to the following features:

' he plug body is formed of two insulating complementary halves which are held together by means of spring clips which permit the jacks to .be madesomewhat smaller than the terminal posts which are received therein whereby the "jacks, may spread when the posts are inserted, the springs serving to cause the jacks thereafter {:to firmlyflgripitheaterminal posts. The plug is {provided.witli'ffingers which serve to space the hebody of the iron to provide for the plug from t r wma Q f" cooling air between the plug and for securing-theplug on the iron in a semi-permanent'fashion in such manner that the plug [may be conveniently removed when necessary and yet may not be repeatedly attached and re- 'moved from the iron in the normal operation thereof. The attaching means acts to prevent weavingand tilting of the plug on the terminal posts when the iron is in service and holds the plug in such manner as toprovide a fixed con- WhilelI have thus described and illustrated a specific embodiment of my invention, I am aware that numerous alterations and changes therein may be made without departing from the spirit 7 of the invention and the scope of the appended claims, in which I claim:

1. A- plug for use with electrical appliances having fixed terminal posts, comprising a body of insulating material formed of two substantially identical halves arranged face to face and having recesses in the faces forming sockets, plug jacks in said sockets for the reception of the terminal posts of an electrical appliance, and spring clips on the outer surface of said plug at oneend thereof for preventing lateral movement of said halves and for urging the halves together to compress the jacks against the terminal posts, said springs carrying depending fingers for spacing the plug from said appliance.

2. A plug for use with electrical appliances having fixed terminal posts, comprising a body ofinsulating material formed of two substantially identical halves arranged face to face-and having recesses in the faces forming sockets, plug jacks in said sockets for the receptionof temiinal posts of an electrical appliance, and spring x theiron the air being circulated .1 around theit'erminal posts, Means are provided andpermit spreading pf the portions at'their lower ends against the tension of the spring clips.

clips on the outer surface of said plug at one end thereof for preventing lateral movement of said halves and for urging the halves together to compress the jacks against the terminal posts, said springs carrying depending fingers for spacing the plug from said appliance, and means on the opposite end of said body holding the halves together when said halves are spread by insertion of terminal posts in said jacks arranged for permanent attachment to the appliance for rigidly holding the plug in position on the terminal posts.

3. A connector plug for electrical appliances having fixed terminal posts, comprising separable body halves with interposed plug jacks at one end and interposed terminal conductor wires emanating from the opposite end, means yieldingly urging the halves together at the plug jack end, means at the upper end of the plug holding the halves together, the latter means having an extension adapted for attachmentto the appliance for rigidly holding the connector plug in position with its jacks plugged onto the terminal posts.

4. A connector plug as set forth in claim 3, in which said plug holding means has a socket for reception of the upper end of the plug body halves for holding the upper end of said halves 7 against separation and said extension is detachable from the appliance to permit removal of the plug from the terminal posts.

5. A connector plug as set forth in claim 3, including depending fingers on the plug jack end of the plug for spacing the plug away from the appliance to allow air circulation between the appliance and .said plugged end.

6. A connector plug for electrical appliances having fixed terminal posts comprising separable body halves with interposed plug jacks at the lower end adapted to be plugged onto said jacks, spring clips on the outer surface of said body halves serving to yieldingly urge them together and by their contact with the interposed jacks to yieldingly compress the jacks against the terminal posts, said spring clip having lugs projecting downwardly beyond the end of the plug body to hold the plug away from the appliance and allow air to circulate under the plug when it is plugged onto the terminal posts, and means at the top of the plug for holding the halves together and permitting separation of the lower ends thereof against the pressure of said spring clips when said plug is plugged onto the terminal posts, said means having an extension arm for rigidly but detachably securing the plug position on the terminal posts.

MICHAEL W. MCARDLE.

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