US2927184A - Silencing means for a. c. switches - Google Patents

Description

March 1, 1960 H. HUBBELL SILENCING MEANS FOR A.C. SWITCHES Filed May 26, 1954 25" 7 22 I VENTOR 2 ATTORNEYS.

United States Patent C) 2,927,184 SILENCING MEANS FOR A.C. SWITCHES Harvey Hubheil, Long Hill, Comm, assignor to Harvey I- Iubbell, Incorporated, Bridgeport, Conn., 21 corporatron of Connecticut Application May 26, 1954, Serial No. 432,406 Claims. 01. 200-166) This invention relates to electric switches, and has for an object to provide a simple and effective silencing means for the switch operating means.

Another object is to provide means for eflecting a gradually increasing arresting movement at the limits of movement of the operating lever of a snap-action switch to eliminate the greater part of the noise usually caused by the means employed for arresting this movement.

With the foregoing and other objects in view I have devised the construction illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications with in the scope of the invention.

In this drawing:

Fig. 1 is a top plan view of the lower portion of one form of snap action switch with the upper half of the body and the operating means removed;

Fig. 2 is a longitudinal section of the assembled switch taken substantially on line 22 of Fig. 1;

Fig. 3 is a similar section substantially on line 3-3 of, Fig. 1;

Figs. 4 and 5 are transverse sections substantially on lines 4-4 and 55 respectively of Fig. 2;

Fig. 6 is a perspective view of the operating lever or handle;

Fig. 7 is a detail on an enlarged scale of the silencing means at the beginning of the arresting operation, and

Fig. 8 is a partial section and partial side elevation of this silencing means showing the pants at substantially the end of the arresting operation.

In the usual snap action switch in which there is a spring which gives a rapid shifting of the switch after the operating lever or handle has been given a partial movement, such, for example, as a spring operated toggle, there is a definite snap or relatively loud noise caused by some part of the handle hitting a limit stop or bumper, and this is true even where a flat surface on the handle engages a rubber or resilient bumper for the arresting efiect. It is an object of the present invention to greatly reduce and practically eliminate this annoying noise. The device is shown in a four-way type of switch comprising two sets of electrical contacts by way of example, but it will be understood it will be used in different types of snap switches such, for example, as one, two or threeway switches.

The device shown for illustrating the invention comprises a switch including an insulating body 10 composed of two sections, a back section 11 and a forward section 12 secured together by a pair of screws 13 passing through the two sections from the rear wall of the section 11 and threaded into any suitable type of mounting yoke 14 on the front side of the body for mounting the device in the usual wall boxes (not shown). The type of switch shown is a four-way type of switch comprising a pair of bowed spring contacts 15 and 16, contact 15 being secured at one end 17 to a binding post connector 18 proice vided with the usual binding post screw 19 for securing a lead wire thereto. The opposite free end of this spring contact carries a contact member 20 movable between two stationary contacts 21 and 22, the contact 21 being mounted on a binding post block 23 provided with the usual binding screw 24 for securing a lead wire thereto.

' The bowed spring contact 16 carries a similar contact '25 movable between stationary contacts 26 and 27, contact 25 being carried by a similar binding post suppont'28 carrying a binding post screw 29 for a lead wire connection. As shownin Fig. 5, the block 23 is connected with the contact 27 by a. cross connector 30, and similarly the block 23 is connected with the contact 22 by a cross connector 31. The fixed end of the contact 16 is connected to a binding post block 32 similar to-the block 18 for mounting the contact 15.

An operating handle or lever is provided for operating the spring contacts 15 and 16 to shift the contacts 20 and 25 carried thereby between the contacts 21, 22 and 26, 27 respectively. This handle or lever, as indicated at 33, is a member of insulating material pivoted by trunnions 34 on opposite sides thereof in recesses 35 in the upper member 12 of the body. The body portion 36 of this lever is extended on opposite sides of the pivot members 34 and on opposite sides of a finger grip 37 for operating the lever or handle, and through it for operating the switch members. For this purpose the extensions, including the trunnions 34, are provided'with cam members 38 for engaging the bowed portions of the contacts 15 and 16 for shifting them downwardly to hold the contacts 2! and 25 away from the contacts 21 and 26 and in engagement with the contacts 22 and 27 when the lever 33 is shifted to one position, that being the left hand position shown in full lines in Figs. 2 and 3. When shifted to the right or dotted line position of Fig. 2, these cams will release the contacts 15 and 16 and permit them to move upwardly and move the contact 20 from engagement with the contact 22 to engagement with the contact 21, and permit contact 25 to move from engagement with the contact 27 to engagement with contact 26.

To effect these movements with a rapid snap action a spring toggle comprising a pivoted rocking member 39 is pivoted by trunnions 46 in recesses 41 in the base member 11 and provided with a lug 42 on which is seated one end of a coil spring 43, the other end embracing a lug 44 projecting from the lever 33 and resting against shoulders 45 on opposite sides of this lug. As the lever is swung between its left and right hand positions indicated by the full and dotted lines in Fig. 2, as it moves through the first half of this movement it compresses the spring 43, and then as it passes through the line joining the centers of the trunnions 34 and 40 the spring operates with a toggle action to shift the lever with a rapid snap action to complete its movement. Because of this, when the lever is stopped at its extreme movement it is in its most rapid movement, and it is ordinarily arrested by means of a fiat surface or shoulder 46 hitting against a stop shoulder or bumper. This gives a rather loud, sharp noise which may be quite annoying, and this is true even though the fiat surface 46 might act against a rubber or similar resilient bumper.

To greatly reduce or practically eliminate the noise there is provided on each of the shoulders or flat surfaces 46 a tapered lug 47, preferably substantially cone-shaped, and mounted in the body member 11 is a pair of bumpers 48, one on each of the opposite sides of the lever, in the paths of movement of the shoulders 46 and the lugs 47. An effective way of mounting these bumpers is to provide the lower wall of the member 11 with circular or cylindrical sockets 49 in which the bumper blocks 48 will be inserted from the top and seated and held in these engages the top flat wall 51 of the bumper block 48.

This lug gradually sinks into the resilient material of the block or bumper, as shown in Fig. 5, under action of the blow of the snap action imparted to the lever 33 by the spring 43, and due to the taper on the lug 47 the arresting action of the block on the lever is a gradually increasing arresting action, so that instead of the lever being stopped by a short blow on a rigid surface it' is stopped by a yielding resilient material, and the action of this material on the lever is a gradually increasing retarding action from a minimum as the smaller end of the lug first contacts the resilient bumper until the tapered lug is fully embedded in the resilient material and the flat surface or shoulder 46 engages the top of the bumper. The tapered lug sort of slides into the yieldable resilient material making its own depression in this material. Eventually the flat surface 46 hits the resilient material, but by that time the speed of the handle has been slowed down so there is no appreciable noise. This action practically eliminates any noise incident to the action of the bumper in arresting movement of the lever, and of course when the pressureof the lever is removed the resiliency of the material of the bumper restores it to its original condition to receive and cooperate with the tapered lug in the arresting of the next movement of the lever. This forms a very simple and eifective means for eliminating the noise incident to the usual hammer blow of a flat surface, for example, against the arresting bumper surface as is experienced in the usual type of operating switch constructions.

Having thus set forth the nature of my invention, I claim:

1. In an electric switch, a movable switch member, an operating means for said switch member comprising a pivoted member including a finger grip for shifting it between on and o positions, a spring toggle shifting the pivoted member to either position with a snap action after partial movement by the finger grip, a bumper block of yieldable rubber-like material positioned to form a limit stop for each movement of the pivoted member, and said pivoted member having a tapered lug with its smaller end arranged to engage the bumper block first and the lug gradually sink into the block in arresting movement of the pivoted member, said tapered lug being normally spaced from its bumper block before movement toward this block and engaging the block only at the end of the snap action movement of the pivoted member.

2. In an electric switch a spring toggle snap-acting lever for operating the switch, a rubber-like yieldable resilient bumper forming a limit stop for movement of said lever, and a tapered lug on said lever in position to engage the bumper for the arresting movement, said lug normally spaced from the'bumper at beginning of movement of the lever under action of the toggle and engag' ing the bumper only at the end of the toggle 'movement, said lug having a pointed end to engage the bumper first so the tapered lug gradually sinks into the material of the bumper for a gradually increasing arresting action.

3. In an electric switch a spring toggle snap-acting lever for operating the switch provided with a shoulder, a bumper of rubber-like yieldable resilient material in the path of movement of said shoulder forming a limit stop for the lever, and a tapered lug projecting outwardly from said shoulder in position for its outer smaller end to first engage the bumper and the lug will gradually sink into the resilient material for a gradually increasing arresting action, said lug normally spaced from the bumper, before movement of the lever and engaging the bumper only at the end of its movement.

4. In an electric switch a spring toggle snap acting pivoted lever for operating the switch provided with a substantially conically'shaped tapered luglocated laterally of its pivot, and a bumper member comprising a block of rubber-like yieldable material cooperating with said lug to arrest movement of the lever under action of saidspring toggle, said lug and bumper so arranged that the outer smaller end of the lug engages the bumper first so the lug sinks gradually into theresilient material for a gradually increasing arresting action, and the lug being spaced from the bumper, at the beginning of the lever movement and engaging the bumper only at the end of its movement under the toggle action.

5. In an electric switch a spring toggle snap acting pivoted lever for operating the switch provided with a shoulder and a substantially conically shaped tapered lug projecting outwardly from said shoulder, and a' bumper comprising a block of rubber-like yieldable resilient material cooperating with said shoulder and lug to limit movement of the lever under action of the spring toggle, the lug being so arranged its outer smaller end engages the resilient material and the lug sinks into it to provide a gradually increasing arresting action before the shoulder engages the bumper, and the lug being spaced from the bumper at the beginning of the lever movement and engaging the bumper only at the end of its movement under the toggle action.

Millermaster Mar. 17, 1931 Despard Aug. 11, 1953

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