US2255669A - Enclosed switch and contact therefor - Google Patents

Description

Filed Oct. 6, 1938 I INVENTOR l WIL and'me M75! af/Qzddcw/.

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Edwin BY I @my Patented Sept. 9, 1941 ENCLOSED SWITCH ANDI CONTACT THERE- FOR Edwin W. Landmeier, Cincinnati, Ohio, assignor to The Wadsworth Electric Manufacturing Company, Covington, Ky., a. corporation of Kentucky Application October 6, 1938, Serial No. 233,615

1 Claim.

The present invention relates to switches and has for an object the provision of an enclosed type switch wherein the moving contact and its operating mechanism are simplified and rendered less expensive to produce while at the same time the efliciency and durability of the switch is enhanced over previously known devices.

Another object of the invention is to provide a simplified novel form of moving contact wherein a maximum effective conductivity is attained at reduced cost in material `and manufacturing operations.

A further object of the invention is to provide a switch wherein the assembly ofthe moving contact carrier and its operating crank is greatly simplified.

These and other objects are attained by the means described herein and exemplified in the accompanying drawing, in which:

Fig. l is a perspective view showing a switch embodying the invention with a fragment of the side wall of the switch box in operative relation thereto.

Fig. 2 is a View taken on line 2-2 of Fig. 1.

Fig. 3 is a view taken on line 3 3 of Fig. 1.

Fig. 4 is a perspective view of the improved moving contact of the invention.

Fig. 5 is an end View of the device shown in Fig. 4.

Fig. 6 is a side elevational view of the switch blade carrier of the device of Fig. 1 removed from the switch, but having the contact blade in position therein.

Fig. 7 is a perspective view showing a modified form of the switch of the invention.

The switch of the present invention may comprise a suitable insulating base I having a slot or way I I, the opposed wall faces I2 and I3 thereof being recessed as at I4 and I5 respectively in order to seat a pair of fixed contacts I6 and I1. In the present embodiment the contact I6 has an angularly turned flange I8 secured in place by a screw I9 which passes through a bore 2l) and threadedly engages in a threaded perforation in said flange. The free end of fixed contact I6 is depressible into recess I4 when sufficient pressure is exerted thereon against the yielding resistance of the metal of said contact. The contact I1 has an angularly turned flange 2| secured by threaded engagement therewith of screw 23 which is also entered from the bottom of the switch base through a suitable bore 24. The projecting ends of the screws I9 and 23 are each adapted to receive a loop of conducting wire and a binding nut (not shown) in order to connect the switch of the invention in an electrical circuit to be controlled thereby.

A switch blade carrier 25 formed of strong insulating material such as hard ber is of such thickness as will enable it to be freely and slidably moved between the adjacent faces of contacts I6 and I1.

In the switch illustrated inFigs. 1, 2 and 3, the blade carrier 2'5 has an elongated slot 26 therethrough which snugly receives a flat operating bar 21. Spaced from slot 26 and adjacentl one edge of insulating blade carrier 25 a substantially rectangular aperture 28 is cut through the carrier 25. A moving contact 29 is floatingly seated in the aperture 28 so that when the carrier is moved between the fixed contacts, the opposed faces of parallel major side walls 30 thereof will effect a snug wiping contact with adjacent faces of contacts I6 and I1. The moving contact 29 forms an important feature of the switch and it distinguishes from previously known and used floating 'contacts in that the weight of metal employed may be reduced to a minimum. The wall structure of contact 29 is continuous, the major side walls 30 being connected together along opposed edges by the integral end walls 3l, thus forming two paths for the flow of current when interposed between fixed contacts such as I6 and I1. The temperature of the cooperating contacts is considerably lower in a given installation utilizing the continuous moving wall contact such as 29 as compared with heretofore known contacts. Contact 29 is formed rapidly and inexpensively and the spacing between outer faces of walls 30 is subject to accurate control, thus assuring smooth operation of the switch in which the contact is employed. The compressive strain imposed upon walls 30 as the contact is slidably moved between the relatively fixed contacts I6 and I1 is uniformly distributed upon the pair of connecting end Walls 3| so that there is no likelihood of crystallization and cracking due to continued manipulation of the switch.

In assembling the switch justl described, contacts I6 and I1 are secured to the base IU whereupon the hollow continuous walled contact 29 is seated in aperture 28 and the carrier is then slipped into the slot in base I9 whereupon the opposed walls of the slot I I preclude further displacement of contact 29. The fiat rod 21 is then entered into slot 26 in the carrier 25 and into suitable bearings which may be formed in the cabinet wall 32 or any other wall structure associated with the switch. By turning operating bar 21 on its longitudinal axis, carrier 25 is mizes the danger of burningthe contacts but.,

the wear due to the frictionV of wiping contact is likewise reduced to -a minimum because of the p compensating self-adjustment o'f the moving contact, 29 in the direction of Athe thickness of switch blade carrier 25.

As illustrated in Fig. 1 the bearing for operating rod 21Ymay be constituted bythe walls of an odd-shaped aperture 33 having arcuate end walls 34 spaced apart at a distance slightly greaterY than the width of operating bar 21 and connected together by side walls presenting op- -posed fulcrum points 35 whichare spaced apart slightly more thanthe thickness of operating bar 21. 'I'he bar 21 inserted in a pair of apertures such as 33 provides anv'inexpensive and easily assembled bearing and limit stops controlling theY degree of rocking movement of the bar and -its associated switch blade carrier 25. A suitable ihandle crank 36 is formed on one end of bar 21.

Itis to be understood that the invention herein is not limited to a structure wherein the insulating switch blade carrier is movable through an arc of a circle. For example, the moving carrier supporting a contact such as 29 may be adapted to rectilinear movement instead of arcuate vmovement. While the retention of contact 29 is desirable by oating support between the walls of the recess in the carrier and the walls of a slot in which said carrier operates, this oating mounting of either the contact or its carrier, or

both may be attained in any other way. For Y convenience, as shown in the embodiment of Fig. 7, the insulating base 31 may take a form comparable to the base l of Fig. 1 and may have the fixed contacts 38 and 39 in the relation described for the corresponding parts in Fig. 1. A strip or carrier of insulating material 40 has an aperture therethrough to receive a moving contact such as 29 adjacent its one end while the remaining* end 4I may be of reduced Width to enable the passage thereof through a restricted slotv in a cabinet wall (not shown) for push and pull operation of the switch from the exterior of such a cabinet. Any suitable handle means such as a bar 42 may be provided on the exteriorly accessible part of the switch blade, What is'claimed is: An enclosed type switch comprising a slotted base of insulating material, a pair of fixed contacts disposed in the'slot adjacent opposite walls thereof, a carrier of insulating material disposed in the slot between said contacts Yand having an aperture therein adjacent an edge thereofV for receiving a moving Contact, and further provided with an elongated slot, a flat bar insaid slot and a cabinet wall having an aperture therein to receive said bar and presenting: opposed fulcrum points on opposite sides of said bar and further presenting arcuate 'edges restraining -edgewise Y movement of the bar and permitting limited rotational movement thereof,

EDWIN W. LANDMEIER.

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