US1720395A - Noiseless switch - Google Patents

Description

July 9, 1929. R. F. GEoRGE NQISELESS SWITCH Filed June 14, 1926 INV ENTOR I F055 FGEO/PGE l A l RNEY III i I 5 I Patented July 9, 1929.

llhllTiED STATES PATENT fil 'l 'ltihl.

BOSS 'F. GEORGE, OF SEATTLE, WASHINGTON.

NOISELESS SWITCH.

Application filed June 14.,

This in rention relates to improvements in electric switches and more particularly to switches of that character adapted for use in connection with the electric commercial appliances and for lighting and heating circuits as commonly installed in residences.

it is the principal object of this invention to provide an electric switch that is distinguished from the usual type of snap switches in that it is practically noiseless in its operation.

More specifically stated, the invention resides in the provision of an electric switch of the above character embodying a contact bar that is manually shiftable to etl'ect the opening and closing of a circuit through the switch and which, at its ends, operates against air cushions which so retard it that its movements under spring tension are rendered noiseless.

Other objects reside in the various details of construction and combination of parts which provides for an easily assembled, easily operated and relatively inexpensive sw tch.

in accomplishing these and other ob]ects of the invention, 1 have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Figure 1 is a vertical sectional view of a switch embodied by the present invention.

Figure 2 is a horizontal section taken on the line 2-2 in Figure 1.

Figure 3 is a front view of the switcln Figure 4 is a sectional view of a switch of an alternative construction.

Figure 5 is a perspective View of apart of the switch shown in Figure 1.

Figure 6 is a sectional view of another alternative form of construction embodying a mercury contact.

Figure 7 is a detail View of another alternative construction.

Referring more in detail to the drawings- 1 designates a switch box, which may be equipped with a removable cover or front plate 2 adapted to he held 111 place by screws 8 and having a central, rectangular opening 1. Fitted within the box, at its opposite ends, respectively, are blocks of insulation 5 and 6 provided with vertically ahned bores or sockets 7 and 8 in which rounded end portions 9 and 10. formedat the opposite ends of acontact bar 11, are slidably contained. The ends 9 and 10 serve to support and to guide the bar in its reciprocal movementand also 1926. Serial No. 115,913.

act as pistons against the air pocketed in the bores to cushion and retard movement of the bar. The bores, or sockets 7 and 8, open through the blocks and register with small air ports 12 in the end walls of the box 1 through which the air may be drawn into or forced from the sockets as the bar completes its movement. There are also air vents 13 leading laterally from the sockets to permit a fast initial movement of the bar but which are closed off by the extensions 9 or 10 when nearin g the inner limit of movement.

Mounted on a block of insulation 15 that is fixed to the back wall of the box: are two y eldable contacts 16 and 17 with which circuit wires 18 and 19 are electrically connected and which, at their outer ends, are vertically alined and are adapted, when the bar 11 is shifted downwardly to on position, to simultaneously engage with the bar to eill'ect an electrical connection between the contacts. When the bar is shifted upwardly to off position, it disengages the lower contact and thus breaks the electrical connection through the circuit Wires. The cont-acts may be of various kinds but are here shown to be in the form of plungers that are slidably contained in housings 20 to which the circuit wires 1.8 and 19 are attached and in which coiled springs 21 are seated to bear against the plungers to yieldably retain them against the bar. The lower contact is limited in its outward movement by a head portion 22 at its inner end which engages with the closed end of its housing so that it cannot moveoutwardly far enough to engage with the guide portion 10 of the bar when the bar is raised to off position.

The means for actuating the switch consists of knob 25 mounted at the outer end of an arm or pair of arms 26 that extend from the cam 27 outwardly from within the box through the front plate opening 4. The cam has trunnions29 at its opposite ends revolubly mounted in supports 30 and 31 and has a lever arm 32 extended in the opposite directions from the arms 26 into a slot 33 formed longitudinally in bar 11. The cam is supported ust within the opening l with its axis tranversely of the opening and a leaf spring 34 is mounted on the inner face of the plate 22 to press against the cam in such mannor as to urge the switch lever toward its limit of movement in one direction or the other after it has been manually shifted past the dead center point; that is, when the the sockets or bores 7 and S.

knob 25 is actuated downwardly from on position as shown in full line position in Figure 1, past horizontal position, at which the cam is at dead center with respect to the spring, the spring acts against the cam to cause the lever to be thrown quickly toward off position. Likewise, when the knob is moved upwardly from oil position, past the dead center, the spring causes it to be thrown towart on position.

Since the vertical movement of the bar 11 is to be relatively short as compared to the movement of thelever 82, the slot 33 is made ofsuch length and is so disposed that its ends will be engaged only as the lever approaches the final movement in one direction or the other. Cushions 14 0t fibre or other suitable material are set within the ends of the slot to be engaged by the lever and when the latter contacts therewith, it causes the bar to be quickly shifted but the final shitting movement is retarded by the air cushions in The air 1', permitted to enter or leave these bores radually tl'n'ough the ports 12 and thus tne bar completes its movement slowly and quietly.

If it is desired, cushions or springs as at may be located in the bores for the ends '5 the guide portions 9 and 10 to seat against.

While I have illustrator the deviceot Figures 1, 2 and 3, asprovided with air cushions at opposite ends of bar 11,'it is possible to provide a device wherein there is a compound air cushion at but one end of the box as shown in Figure 7 and the extension 9 ot the bar has a head 71 at its end that is movable into air pockets or against cushions 70 and switch lever 32 has a rotatable connection about the axis of the cam 27 and at its outer end it carries an arcuate cross head 40 with rounded extension 41 at its ends adapted to seat within sockets 4-2 in a mounting block L3. The rotative movement of the switch lever 32 on the cam is limited by the contacting of a pin 47 carried by the lever with the ends of a slot 48 formed in a circumferential direction in the cam and which is o1 such length that the cam may be moved to about the dead center point with respect to the spring 3% before the switch will be moved and the latter will then be snapped quickly to the other position. As the extensions 41 move into their respective sockets when the switch is. actuated from one position to another, the movement is retarded by the trapped air which so cushions the switch that no noise is perceptible. Small ports, as at 414:, may be provided for the slow escape of the air from r the sockets.

In this latter switch the cross head is provided with knife contacts engageahle with yieldable, leatl. contacts to and, All with which circuit wires are connected.

In Figure 6 is illustrated another alternative construction. The construction consists of a mercury tube 50 having vertical. end portions 51 and and a lower end connecting portion formed with a central hump or raise 53. A pair of contacts 54 and enter the tube at one side of the hump and these are connected with the circuit wires. Slidably titted in the vertical ends of the tube are plungers 56 and 57 and these have a lost motion connection at their outer ends with a switch lever 58. The lever is pivotally mounted centrally between the connections with the plungcrs so that when it is shil'tcd, the plnncers move in opposite directions to cause the icrcury contact 0 contained in the tube to he forced from one side oi the hump to the other to quickly break or open the circuit as it is moved into and from circuit closing I'clation with the contacts 5% and The switch lever is equipped with a cam 61 at the mounting point against which a spring (32 bears to throw it to one position or the other after the lever is actuated manually past a center point and the final movement of the lever is retarded by the action ot a plunger (34: at the end of a continuation of the piece so an inst an air cushion within a cylinder (37; this being a modification of the retarding means previously described but operating on, the same principle.

In Figure '2' is illustrated a slight modification in construction for a. cushioned switch bar wherein the plunger moves during its final inward movement into an air pocket at the end of an enlarged cylinder 7 1.

Having thus described my invention, what claim as new therein and desire to secure by Letters-Patent, is:

1. In a switch of the character described, a pair of circuit contacts, a switch bar movable longitudinally inlo and from circuit closing relation with said contacts, a pivotally mounted lever manually operable to actuate the switch bar in opposite directions, a pair of mounting blocks having sockets therein for receiving the ends of the switch bar and cushioning means in said sockets against which the ends of the bar will engage to retard its final movement when shifted from one position to the other.

2. In a switch of the character described, a circuit closing bar, means operable to shift the bar to open or close a circuit through the switch, a pair of blocks provided with sockets for receiving the ends of the bar when shi tted in opposite directions and providing air cushions for retarding final movement of the bar; said pockets having ports of restricted area thereinto for the escape or inlet of air.

3. In a switch of the character described, a pair of circuit contacts, a switch bar adapted ill) lit!) to be moved into and from circuit closing relation with said contacts and having gulde portions at its ends, a pair of blocks provided with sockets in which said guide portions are slidably contained; said sock ts providing air cushions against which the bar operates when shifted from one position to another and means for yieldably retaining the bar at its different positions.

4. In a switch of. the character described, a plurality oi circuit contacts, a switch bar adapted to engage the contacts and having guide portions at its ends, socketed mounting members slidably containing said guide portions and providing air cushions for retarding movement of the bar, a pivotally mounted cain, an actuating lever for the cam, a s ning bearing against the cam to throw it to different positions after being manually actuated by said lever past a dead center position and a switch bar actuating lever extended from the cam and having a lost motion connection with the switch bar which provides that the bar be moved thereby after the cam has been moved past its dead center position.

5. In a switch of the character described, a plurality of circuit contacts, a switch bar adapted to engage the contacts having a longitudinally directed slot therein and having guide portions extending from its opposite ends, a pair of insulated mounting blocks provided with sockets wherein said guide portions of the bar are slidably fitted and providing air cushions for retarding movement of the bar; said sockets having ports oi restricted area tor the escape or inlet of air, a pivotally mounted switch actuating lever having one end portion extended tl'n'ough said bar slot, a cam on the lever and a spring bearing against said cam to retain the bar at its different positions.

6. A switch of the character described comprising a housing provided with a front opening, a pair of yieldable contacts mounted in the housing, insulated mounting blocks fixed Within upper and lower ends of the box having vertically alined sockets therein, a switch bar engageahle with the contacts and having guide portions at its ends slidably contained in said sockets; said sockets providing air cushions against which the bar operates when moved from one position to another, a cam rotatably mounted within the housing, a lever extendin from the cam and having operative connection with the bar, an

actuating lever extending from the cam through said housing opening and provided with an actuating knob at its outer end, and a spring mounted in the housing and bearing against the cans to actuate it and the switch bar to one position or the other when shifted past a dead center point.

Signed at Seattle, lVashington, this 4th day of J one, 1926.

ROSS F. GEORGE.

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