US2558223A - Centrifugal switch structure - Google Patents

Description

June 26, 1951 R. REGER CENTRIF'UGAL SWITCH STRUCTURE Filed July l2, 1947 Patented June 26, 1951 CENTRIFUGAL SWITCH STRUCTURE Raymond Reger, Anderson, Ind., assignor to The Pierce Governor Company, Inc., Anderson, Ind.,

a corporation Application July 12, 1947, Serial No. 760,666

7 Claims. l

This invention relates to an overcenter operable switch structure.

The chief object of this invention is to provide a speed responsive switch that does not fluctuate to and fro in making contact and breaking contact at thecritical speed, which action is commonly called hunting the switch thus making contact and maintaining contact at a critical speed and breaking contact and maintaining open circuit condition at any other speed on the same side of the critical speed, as for example lower speeds.

Obviously the invention can be, arranged to open a circuit instead of close a circuit at critical speed, this being a reverse arrangement. The circuit herein can be utilized for direct power control or for pilot control, that is, in a remote control system. The present disclosure of the invention is represented as a centrifugally operable switch device.

The chief feature ofthe present invention resides in providing Ian oscillatable arm or fork and an arm including a switch member of a snap action type so that switch hunting if any, within a very slight variation of force, at the critical or predetermined force will not reversely actuate the switch.

Other objects and features of the invention will be set forth more fully hereinafter.

The full nature of the invention will be understood from the `accompanying drawings and the following description and claims.

In the drawings- Fig. 1 is a side elevation of a centrifugally operable switch structure embodying the invention, the cover plate being removed.

Fig. 2 is a plan View of the invention, the switch housing being shown in section.

Fig. 3 is a view similar to Fig. 1 and of a modified form of the invention.

Fig. 4 is a view similar toFig. 2 and of the form shown in Fig. 3, the major portion of the centrifugal portion being omitted.

In Fig. 2 of the drawings there is illustrated in dotted lines the interior mechanism of a centrifugal governor such as illustrated, described and claimed in copending application Serial No. 642,149 filed January 19, 1946 and entitled Compact Centrifugal Governor, which application was subsequently abandoned, and formally made a part hereof, which mechanism generally will be hereinafter more fully referred to.

In Fig. 1, I indicates a housing generally and from which projects a rock shaft II. The housing may include the exterior chamber forming walls I 2 and suitably secured within the chamber is bracket I3 having spaced arms I4 and I5 provided with aligned apertures.

A threaded stem I6 is disposed therein and mounts a lock nut I'I at one end and terminates in eye I8 at the opposite end. A concentric spring 9 at one end bears upon arm I4 and at its opposite end bears upon stop I9 carried by stem I6 between the arms.

Rock shaft II has rigidly secured to it within said chamber the insulation block 20a to which is secured the arm 29. This arm is provided with a, longitudinally disposed series of apertures 2|. Secured to eye I8 is one end of a spring 22, the other end 22a being selectively associated with the desired aperture 2|. Spring 22 is the governor load spring and its force is adjusted by advancing or retracting the stem I6 toward and away from arm 20. Other adjustment is eected by selecting the desired aperture 2| for spring mounting purposes.

Block 2lia has disposed in transverse relation to the longitudinal axis of arm 2S a pair of spaced stops 23 and 24. These are offset radially from the shaft. Stop 24 includes contact 25 and connected thereto is pigtail 2E, same being connected to insulated terminal 2'! carried by wall I2.

Disposed between the stops is a contact 28 carried by portion 29, see Fig. 2, of a member having spaced arms 3d and intermediate arm 3l. The outer arms are bowed and the intermediate arm is generally straight. An insulation block 32 is suitably secured within the chamber as at 33 and carried thereby is the U-shaped conductor having arms 34 notched on the ends at 35, see Fig. 1, and the midportion 36 disposed in contact with the extended portion of arm 3l. Arms 30 are fulcrumed in notches 35. A connecting screw 3l serves as an anchor for terminal strip 38connected to insulated terminal post 39 also carried by wall I2 of the chamber.

The resulting structure is a snap action switch actuated by rock shaft II upon counter-clockwise rotation in opposition to load spring 22 and in accordance with centrifugal force 0f the governor generated in accordance with or proportional to the power speed.

The switch is so arranged that the circuit is normally open below governed speed and at governed speed the circuit is closed by the switch. This is eifected as follows: AS the stop 23 moves counter-clockwise, contact 28 is carried therewith. When carried beyond the equilibrium or central position, the member 29 snaps overcenter 3 and contact 28 immediately engages terminal member 25 to complete the circuit.

Obviously if member 25 were applied to stop 23 instead of stop 24 the switch would be normally disposed in closed circuit condition and snap overcenter to the open circuit condition.

Reference will now be had to Figs. 3 and 4. Herein the governor housing has projecting from same into the chamber formed by walls |2, the governor or speed responsive rock shaft which mounts slightly arched arm |2l having two concentric series of holes |2|, same being staggered as shown.

Load spring |22 has its end |22a selectively associated with the desired hole |2| for properv adjustment. The other end of lsaid spring is secured in aperture H8 in the confronting end vof member H5. Bracket ||3 includes spaced guidel portions ||4 and H5 and member H6 is secured in adjusted position by nut lll.

Concentric with member lit is spring |99 which bears at one end against portion I4 and at its opposite end uponretainer H9 fixed to member The general similarity of this form to that shown in Figs. 1 and 2 will be obvious.

Rigid with arm and shaft I|| is a transversely disposed arm |2la and same mounts stop pins |23 and |24 spaced apart as shown. The latter may have suitably secured to it contact |25 electrically connected by pigtail or like member |25 to insulatably mounted terminal post |27.

Wall ||2 of the chamber insulatably supports terminal post |39 and lead |38 is connected to terminal screw I3? carried by current conducting member |32 insulatably secured as at |33 and 333a to the back wall of the chamber.

Herein member |32 includes portion |34 grooved as at |35. A pair of flat spring arms |39 are pivoted therein and the opposite ends terminate in a common portion |29 carrying contact |28, the latter and the free end of portion |29 being disposed between stop |23 and |24 for selective operative contact therewith.

Disposed parallel to portion |34 of member |32 Y is a similar portion |36 aperturedat |32a to take one end of spring |3|, the other end being elongated at I3 ia to extend through aligned aperture Hille, the other end being anchored as at |29a to switch portion |29.

The switch construction hereof operates simibracket portion |36 in any well known manner,

to wit, an eye bolt threaded in aperture |36a and locked by a nut if desired.

In Fig. 2, 4Q indicates a speed driven member mounted on a shaft 4| rotatably supported in the housing l0. A sleeve 42 is slidable on said shaft and is operatively associated with race structure 43 that is engaged by yoke 44 carried by said shaft Shaft 4| mounts plate or spider Q5 to which is pivoted at 46 weight members 41, the tails 43 of which bear against the adjacent end of sleeve 42.

Normally load spring 22 constrains the shaft yoke 44, and sleeve 42 to the position wherein 4 suiicient, centrifugal force overcomes the force of the load spring 22 and the rock shaft I| is rocked or oscillated. This occurs at the predetermined speed.

Since shaft movement is gradual or progressive in the neighborhood of governed speed, speed uctuation would alternately open and close the circuit due to hunting and surging. Snap action, herein, insures that the desired circuit is effected at the desired speed, alternate circuit reversals in the neighborhood thereof are prevented, and in opening the circuit, the arc does not hang on but immediately dies out, thus prolonging the life of the contacts 25-28 or |'25-'|23. This means that high cost, long life, arc resisting contacts are not necessary.

While the invention has been illustrated and described in great detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character.

The several modifications described herein as well as others which will readily suggest themselves to persons skilled in this art, all are con- Y sidered to be within the broad scope of the invention, refer-ence being had to the appended claims.

The invention claimed is: l. In a device of the character described, in combination, a centrifugally operated rock shaft, an arm carried by said shaft and extending at an angle to the axis of said shaft, a biasing spring having one end stationarily anchored and the opposite end connected to said arm, a pair of space-d apart stop arms carried by said shaft extending at an angle to said arm and rockable by said shaft, a contact mounted on one of said stops, a flexible plate contact carrying arm rigidly supported at one end and having a free end disposed between said stop arms andmovable by said stop arms in opposite directions by said stop arms when the same are rocked by the rocking movement of said shaft and means for biasing the free end of said plate in either direction when the plate is moved past dead center in either direction by engagement with said stop arms.

2. In a device of the character described in combination a centrifugally operated rock shaft, an arm carried by said shaft and extending at an angle to the axis of said shaft, a biasing spring having one end stationarily anchored and the opposite end connectible at Variable points along the length of said arm, a pair of spaced apart stop arms carried by said shaft extending at an angle to said shaft and rockable by said shaft, contact means mounted on one of said stop arms, a flexible plate contact carrying arm rigidly supported at one end and having its free end disposed between said stop arms and movable by said stop arms in opposite directions when the same are rocked by the rocking movement of said shaft, and means for biasing the free end of said plate in either direction when the plate is moved past dead center in either direction by engagement of said stop arms.

3. In a device of the character described in combination, a centrifugally operated rock shaft, an arm carried by said shaft and extending at right angles to the axis of said shaft, a biasing the weights 41 are collapsed toward the shaft spring having one end adjustably stationarily anchored and the opposite end connected to said arm, a pair of spaced apart stop arms carried by said shaft extending at an angle to said shaft and rockable thereby, a contact mounted on one of said arms, a flexible plate contact carrying arm rigidly supported at one end and having its free end disposed between said stop arms an-d movable by said stop arms in either direction and movable by said stop arms in opposite directions when the same are rocked by the rocking movement of said shaft and means for biasing the free end of said plate when the plate is moved past dead center in either direction by engagement of said stop arms.

4. A switch assembly comprising a centrifugally movable non-rotatable rock shaft, centrifugally operable rotative means for rocking the shaft, angularly disposed arms oscillatable thereby, a pair of supports, one being in `general alignment with the longitudinal axis of one of the arms and the other support being directed substantially transverse to the similar axis of the other arm, a load spring operatively connected at one end to the said other arm and at its opposite end to the support directed transverse thereto and normally opposing rocking of the shaft by the said rst mentioned means, to and fro movable switch means carried by the said one support and directed toward the arm aligned therewith, spaced stops determining the extent of the to and fro movement, spring means biasing the switch means to either of the to and fro positions when moved toward the same and beyond REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,357,734 Shivers Nov. 2, 1920 2,113,645 Bone Apr. 12, 1938 2,189,996 Riche Feb. 13, 1940 2,236,699 Riche Apr. 1, 1941 2,326,760 Clare Aug. 17, 1943 2,356,202 Benjamin Aug. 22, 1944 2,439,747 lNelson Apr. 13, 1948 2,464,853 De Marco Mar. 22, 1949

Images