US 2628293 A
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Description (OCR text may contain errors)
1953 J. H. WILLIAMS ETAL 2,628,293
I ELECTRIC SWITCH Filed Jan. 9. 1952 INV NTORS.
Patented Feb. 10, 1953 UNITED STATES PATENT ELECTRIC SWITCH John. H. Williams, Barringion, and Edward J. Mastney, Berwyn, Ill., assignors to Oak Mfg. 00., a corporation of Illinois Application January 9, 1952, Serial No. 265,584
This invention relates to an electric switch and particularly to a construction for operating a rotary switch through a predetermined angle of movement.
In certain types of apparatus, particularly portable radio receivers of the type adapted for operation either from a battery or from a power line, it is customary to provide a switch construction for changing from one type of operation to the other. Such receivers have a line cord terminating in a conventional two-prong plug which may be inserted into a conventional wall-type socket for connection to a 110 volt power line. When the receiver is to be used on battery, the line plug is inserted into a special receptacle by the receiver. This receptacle includes a switch which is operated by one of the prongs of the plug to change the internal circuits of the receiver so that battery operation is possible.
This invention provides a construction which is an improvement upon such switch mechanism.
In order that the invention may be understood, it will be explained in connection with the drawing wherein:
Figure 1 is a side elevation of a construction embodying the present invention, an operating plug being shown ready for insertion into the switch;
Figure 2 is a front view on line 22 of Figure 1;
Figure 3 is a side view similar to Figure 1 but showing the mechanism in a different position with the plug fully inserted;
Figure 4 is a top view along line 4-4 of Figure 3.
The construction embodying the present invention has frame generally indicated by numeral I!) and consisting of front portion II and side portions I2 and I3, respectively. Front portion II of the frame is provided with slots I5 and I3, these slots being transverse to the long dimension of front portion II and being spaced and dimensioned to accommodate prongs I8 and I9 of plug 2%.
Slot I6 and prong I9 have no function as far as switch operation is concerned. It is understood that it is immaterial which particular prong of plug 2!] is used, since the construction is not polarized. Thus, plug 29 may be turned around so that prong I9 simply refers to the lower prong.
Slot I5 has the right portion thereof, as seen in Figure 2, enlarged to form a transverse slot 2|, slots I5 and 2| together forming a generally T-shaped composite slot.
Part I2 of the frame extends for a sumcient distance to provide part 23 for supporting one end of a short stub shaft 24 forming part of a rotary switch. Part 23 of the frame also has car 25 to which may be anchored one end of coil spring 26.
Rigidly attached to stub shaft 24 is switch operating member 21 consisting of an irregularlyshaped piece. Member 27 has ear 28 for supporting the hooked end 29 of coil spring 26. The other end of coil sprin 25, indicated by numeral 3|, is looped over car 25 so that the coil spring biases part 2? to the position shown in Figure l.
Member 2'! has edge portion 32 term nating in tip port on 33 bearing against in-ide surface 34 of front portion I I of the frame. It is understood that coil spring 3'! presses member 2! so that tip 33 is in the position shown.
Part I3 of the frame is large enough to support stub shaft 24. As seen in Figures 2 and 4, member 2! is disposed between sides I2 and I3 of the frame. Thus, actuating portion 32 and tip portion 33 of member 21 comes behind slot I5 and is normally engaged by prong I8 of the plug when inserted. Member 21 has concave part 35 adjacent to actuating portion 32 so that when prong I8 is inserted, the tip of the prong will ride along actuating part 32 of member 21, this actuating part functioning as a cam surface and finally permits the tip of prong I8 to enter concave region 35 of member 21. In this position, as shown in Figure 3, member 21 has been turned again"t the bias of spring 30 counter-clockwise through a predetermined angle, and member 21 and the prong will be stable.
Secured to stub shaft 24 is portion 3'! of a 1'0- tary switch section generally indicated by numeral 38. Switch section 38 has stator 39 rigidly secured to the frame as by staking ears 40 and II extending from side I3 of the frame. Switch section 3'! may be of any desired construction and is conveniently one section of switch as disclosed, for example, in Patent 2,186,949, issued on January 16, 1940. Instead of one switch section, a plurality of sections may be provided.
The particular switching arrangement and contact arrangement in the switch section is not important, as far as this invention is concerned. However, such switch sections have appreciable drag and thus the entire actuating mechanism for the switch presents a substantial load upon prong I8 of the plug. As is well known, most plugs have prongs I8 and I9 disposed in a rubber molding or in a suitable flexible mount so that some play of the prongs is permitted.
The tendency of one prong to move with respect to the other prong thus makes it difficult for a plug of this character to operate the mechanism so far described. In order to support prong I8 against displacement from the desired path of travel during switch operation, side I3 is punched out to provide strips AI and 42 generally extending toward each other, as seen in Figure 2, but having the opposing edges spaced from each other to provide a gap. The gap between supporting members AI and 42 is substantially equal to the width of slot l5 and permits prong [8 to slide between these two supporting members.
As is evident from Figures 1 and 3, supporting members 4! and 42 extend for a substantial distance along side l3 in back of front part I l of the frame so that the major portion of the length of prong I8 is supported against movement toward or away from prong l9. Thus the load upon prong l8 will have no tendency to bend or damage the actuating prong of the plug upon insertion into the switch mechanism.
It is understood that the frame and the various parts thereof, such as the sides, spring and the like, are made of steel or other sheet metal.
What is claimed is: 1. A switching mechanism comprising a rigid said frame, said member having a cam portion movable with member rotation to and from the rear surface of the front part of the frame, spring means for biasing said member so that the cam portion is at the rear surface of the front portion of said frame, said cam portion lying rearwardly in line with said slot, and spaced supporting members carried by one of said frame side portions, said supporting members extending rearwardly of the front frame portion and forming a channel which is a prolongation of said slot whereby a pronged member inserted into said slot to engage the cam portion for turning said member will have support, switching means having stationary and movable contact portions, means for securing the stationary contact portion to said frame and means for coupling said rotary member to said movable contact portion.
2. The structure according to claim 1, wherein said member has a cut-out adjacent the cam surface into which the prong end may rest when the prong is fully inserted.
JOHN H. WILLIAMS. EDWARD J. MASTNEY.
No references cited.