US3249711A - Speed responsive device - Google Patents

Description

May 3, 1966 J. H. sTREsEN-REUTER ETAL 3,249,711

SPEED RESPONSIVE DEVICE Filed June 5, 1964 United States Patent 3,249,711 SPEED RESPUNSIVE DEVICE .lohn H. Stresen-Reuter, Birmingham, and `lohn F. Vismara, Detroit, Mich., assignors to Holley Carburetor Company, Warren, Mich., a corporation of Michigan Filed .lune 5, 1964, Ser. No. 372,910 3 Claims. (Cl. Z110-80) This invention relates generally to electrical switches, and more particularly to a switch having means for actuating an electrical switch in response to some sensed speed.

There are many .applications wherein it is desirable to operate a switch as a function of the speed of an associated engine. For example, in conjunction with the development of automotive gas turbine engines, it has been found desirable to provide means for actuating a switch so as to cut olf the igniter system upon attainment of a predetermined engine speed.

Accordingly, a general object of the invention is to provide a switch having means responsive to sensed engine speed for opening the switch when the engine reaches a predetermined speed.

Another object of the invention is to provide such means which transforms a rotary motion indicative -of engine speed into a corresponding linear motion.

Still another object of the invention is to provide such a means which is compact in design and eicient in operation.

A more specific object of the invention is to provide such a means .comprising a sleeve slidably and rotatably mounted on la rotating shaft, a novel centrifugal means for moving the sleeve axially along the shaft while both are rotating, and an associated L-shaped lever, one leg of which is actuated about a pivot at the juncture between its legs in response to the axial movement of the rotating sleeve, the free leg being associated with a switch for opening and closing the same.

A further object of the invention is to provide such a means which includes a through drive feature, enabling it to additionally operate a speedometer or a tachometer cable.

A still further object of the invention is-to provide such a means which includes mechanism for limiting the force applied to the switch during overspeed conditions.

- Other objects and advantages of the invention will become more apparent when reference is made to the follow# ing specification and the accompanying drawings wherein:

FIGURE 1 is a side elevational view of a switch embodying the invention;

FIGURE 2 is an end view, in fragmentary cross-section, taken along the plane of line 2-2 of FIGURE 1 and looking in the direction of the arrows;

FIGURE 3 is a fragmentary cross-sectional view taken along the plane of line 3-3 of FIGURE l and looking in the direction of the arrows;

FIGURE 4 is a fragmentary cross-sectional view taken along the plane of line 4-4 of FIGURE 1 and looking in the direction of the arrows; and

FIGURE 5 is a fragmentary cross-sectional view of a modification of the invention.

Referring now to the drawings in greater detail, FIGURE l illustrates a speed responsive switch assembly 10, including a lightweight housing 12 having a chamber 14 formed therein and closed at one end by a cover plate 16, the latter being fastened to the housing 12 by any suitable means such as bolts 18. The opposing end 19 of the housing 12, as well as the hub 20 of the cover plate 16, are externally threaded and have openings 21 and 22 ICC formed therein, Bearings 24 and 26 may be inserted in the openings 21 and 22, respectively.

A shaft 28, which extends through the chamber 14, is fitted at its ends into the bearings 24 and 26. A collar 30 may be formed on or secured to the shaft 28 in order to control the depth to which the shaft 28 is inserted into the bearing 24 in the housing 12.. A connecting means, such as non-circular holes 32 (FIGURES 1 and 2), may be formed in both ends of the shaft 28 suitable for Areceiving a driving means, such as a flexible cable 33. A hanged sleeve 34 is slidably mounted around the shaft 28 such that the flanged end 36 is adjacent the collar 30, and a suitable bearing 38 is secured to the sleeve 34 adjacent the ilange 36. A recessed washer 40 is loosely mounted around the sleeve 34 and positioned with its outer edge 42 against the bearing 38.

A rectangular or other suitably shaped block 44 is secured to the sleeve 34 at a predetermined distance :from the flange 36, and a second block 46 is iixedly secured to V,the shaft 28 rat a point adjacent the cover plate 16. The

block 46 may be secured to the shaft 28 by any suitable means such as by a pin 47 aligned in holes formed through the block 46 and the shaft 28. A suitable resilientmeans, such as a spring 48, is confined between the block 46 and spring retainer -49 adjacent the bearing 26 and serves to hold the bearing 26 in the cover plate 16.

Two pair of U-shaped round wire links 50 and 52, each link having one long and one short leg identied as 54 and 56,. respectively, (FIGURE 3,) serve to connect the two rectangular blocks 44 and 46 and to thereby cause the lsleeve 34 to rotate lwith the shaft 28. Due to the pivotal connections described below, the links 50 and 52 also permit the sleeve 34 to move axially along the shaft 28 a distance which has a linear relationship tothe speed at which the shaft 28 is rotating. The longer legs 54 are pivotally retained within openings 58 yformed through the two rectangular blocks 44 and 46 `by means of cotter pins 60 (FIGURE 1) inserted through transverse openings 62 (FIGURE 3) formed through the exposed ends of the longer legs 54. v

As illustrated in FIGURE 3, the longer legs 54 are inserted through the openings 58 in the rectangular blocks 44 and 46 in opposite directions, thereby causing the short legs 56 of opposing links 50 or 52 to be pointed toward one another. Each of the pair of ilyweight balls 64 has a diametrical hole 66 formed therethrough to receive the short legs 56 of the opposing U-shaped links 50 or 52. However, the short legs 56 are first inserted through the round and elongated openings 68 andv 70, respectively, formed near' the ends of each thin metal strap 72, as illustrated in FIGURE l. That is there is a strap 72 on each side of the balls 64 and each strap 72 has a round opening 68 and -a slot 70, the straps 72 serving to limit the outward movement of the balls 64.

A generally lL-shaped lever 74 having a forked end 76 i (FIGURE 4) formed in its leg 78 suitable for straddling the sleeve 34 between the rectangular block 44 and the washer 4t), is pivotally mounted at the juncture 8i) between its legs 78 and 82 in the cham-ber 14 by means of 'a pivotpin 84 secured to lthe housing 12. A suitable resilient means, such as a spring 86, is mounted between a spring seat 88 and a projection 90 formed on the leg 82 of the L-shaped llever 74. An adjusting screw 92 mounted in a threaded opening in the wall of the housing 12 and abutted at its internal end 94 against the spring seat 88, serves to permit manual adjustment of the spring 86.

A standard electrical switch 96 having a pair of leads 98 and 100 (FIGURE 2) extending therefrom is adjustably mounted within the chamber 14 by means of a metal bracket 102, the latter being fastened d-own by screws 103. The bracket 102 contains an elongated opening 104 near one of its ends suitable for permitting manual adjustment of the switch 96 toward or away from the bent end 106 of the L-shaped lever 74 for proper alignment therewith. The detailed internal structure of the switch 96 is not material to the invention, the particular switch shown being normally closed by a spring and being opened by upward movement of the actuator 107 by the end'106 of the lever 74.

Operation In a typical application, the shaft 28 is rotated by the flexible cable 33, which may be connected between the square opening 32 of either end of the shaft 28 and a gear reduction system (not shown), in some direct proportion to the speed of a gas turbine engine (not shown). The threaded ends 19 and 20 facilitate mounting the speed responsive switch 10 on any suitable support structure. As the speed of the shaft 28 and the associated sleeve 34 increases, the resultant centrifugal force moves the balls 64 outwardly, the short legs 56 of the U-shaped links 50 and `52 being free to pivot in opposite directions within ythe opening 66 formed through the balls 64.

As the balls 64 move outwardly, the distance between the opposing longer legs 54 of the U-shaped links 50 and 52 is decreased, and the rectangular block 44 secured to the sleeve 34 is pulled toward the block 46 secured to the shaft 28. This, of course, moves the sleeve 34 axially along the shaft 2S. The bearing `38 and the washer 40, as well as the forked end 76 of the leg 78 of the L-shaped lever 74, will likewise be moved axially along the shaft by the fiange 36 formed on the sleeve 34. The cooperation of the bearing 38, the collar 36, the recessed washer 40 and the forked end 76 .of the lever 74, permits the collar 36, sleeve 34 and inner race of the bearing 38 to rotate at the same time'that the outer race of the bearing 38, the washer 40 and the forked end 76 of the lever 74 are moved axially to the right in -FIGURE 1,

ythe lever 74 pivoting counterclockwise about the pivot pin 84 against the force of the spring 86. The other end 106 of the L-shaped lever 74 is thus moved upwardly in FIGURE 1 against the normally closed switch 96, thereby breaking the circuit which act-uates, for example, the igniter plugs (not shown) of the turbine engine. This, of course, would render the igniter system of the engine inoperative.

FIGURE modification When desirable, the cover plate 16, the bearing 26, the spring 48 and the flexible cable 33 may be eliminated, and the shaft 28 may be connected directly to some driving unit, such as the unit partially illustrated in FIG- URE 5 and identified as 108. In this instance, the square hole 32 in .the end of the shaft 28 (FIGURE 2) would be replaced by a slot 110 receiving a pin 112 having the ends thereof fixed in the shaft 113 having an opening 114 to receive t-he shaft 28. A spring 116 may be located in the opening 114 to keep the shaft '113 from creeping tothe left along the shaft 2'8 and also to aid the spring 86 of the lFIGURE 1 embodiment in holding the collar 30 against the bearing 24 through the L-shaped lever 74.

As modified, the housing 12 may have a flange 118 formed thereon including holes 120 for mounting purposes.

Summary It should be apparent from the above discussion that the invention provides novel means for actuating an electrical switch -in response to speed. Since the lever structure provides mechanical amplification of the speed sense, as compared to the usual centrifugal fiyweight arrangement, the device may be more compactly packaged. It is further evident that a driving unit, such as the fiexible cable illustrated in FIGURE l, may be connected to i either end of the shaft at random, with the same efficient result. The through drive feature obviously enables the other end of the shaft to be put to use driving an accessory item, such as a speedometer or a tachometer. A

Once the switch is opened by the L-shaped lever at the predetermined speed, additional movement by the lever is not necessary and, in fact, may be harmful to the switch at excessively high shaft speeds. Hence, it is evident that the straps associated with the balls and U-shaped links serve to limit the force which the L-shaped lever may exert on the switch, while not in the least interfering with the rotation of the shaft and sleeve.

The length of the slots 70 and 104, the force of the lsprings 48 and 84, the weight of the balls 64 and the dimensions of the lever 74 are some of the design factors that may be varied to change the operating characteristics of the switch v10.

Although but two embodiments of the invention have been disclosed and described, it is apparent that other modifications are possible within the scope of the appended claims, including -uses other than a switch.

What we claim as our invention is:

1. A speed responsive switch device, comprising a rotatable shaft, a sleeve slidably and rotatably mounted around said shaft, a first member fixedly attached to said sha-ft, a second member fixedly attached to said sleeve, a pair of U-shaped links pivotally connected along one leg thereof to each of said first and second members, a weight having an opening therethrough for receiving the other leg of each opposing pair of links, pivotable means operatively 'connected to said sleeve for axial movement therewith, and a rigid member operatively connected to said links for positively limiting the outward movement of said weights, said member being pivotally connected at one end thereof to one link of one of said pairs of links and having a slot formed near the other end thereof, said slot receiving one link of said other pair of links.

2. A speed responsive switch device, comprising a shaft, means for rotating said shaft, a first member fixedly attached to said shaft, a sleeve slidably mounted around a portion of said shaft, a fiange formed on one end of said sleeve, a second member 4fixedly attached to saidV sleeve, a bearing surrounding said sleeve and positioned betweensaid second member and said ange, a pair of U-shaped links pivotally connected along one leg thereof to each of said first and second members, a weight having an opening therethrough for receiving the other leg of each opposing pair of links such that the other end of said sleeve is located a predetermined -distance away from said first member while said shaft is not being rotated and with said predetermined distance diminishing with increased centrafugal force on said Weight and said links, a strap pivotally connected at one end thereof to one of said links and having a slot formed in the other end thereof receiving and permitting limited movement therein of an opposing link, a pivotabl-e L-shaped lever having one forked end straddling said sleeve between said bearing and said first member, and a switch associated with the other end of said L-shaped lever. n

3. A speed responsive actuating assem-bly, comprising a housing forming a closed chamber, a shaft extending through said chamber and mounted for rotation therein, a sleeve mounted on said shaft so as to be movable rotationally and axially with respect to said shaft, a first cross member mounted for rotation with said shaft, a second one of said linkage means and including a slotted opening in the other end for receiving the other of said linkage means, an abutment formed on said sleeve, a member to be actuated mount-ed within said housing, an L-shaped'lever pivotally mounted at the juncture of its legs to said housing, `one leg of said lever engaging said abutment on said sleeve and the other leg of said lever being positioned to operate said member .to be actuated upon attainment of a predetermined speed of said shaft,

1,491,712 4/1924 Low -200-80 X 3,005,886 10/1961 Yeager ZOO-80 6 FOREIGN PATENTS 283,317 4/1915` Germany.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

H, A. LEWTTER, Assistant Examiner.

Claims (1)

1. A SPEED RESPONSIVE SWITCH DEVICE, COMPRISING A ROTATABLE SHAFT, A SLEEVE SLIDABLY AND ROTATABLY MOUNTED AROUND SAID SHAFT, A FIRST MEMBER FIXEDLY ATTACHED TO SAID SHAFT, A SECOND MEMBER FIXEDLY ATTACHED TO SAID SLEEVE, A PAIR OF U-SHAPED LINKS PIVOTALLY CONNECTED ALONG ONE LEG THEREOF TO EACH OF SAID FIRST AND SECOND MEMBERS, A WEIGHT HAVING AN OPENING THERETHROUGH FOR RECEIVING THE OTHER LEG OF EACH OPPOSING PAIR OF LINKS, PIVOTABLE MEANS OPERATIVELY CONNECTED TO SAID SLEECE FOR AXIAL MOVEMENT THEREWITH, AND A RIGID MEMBER OPERATIVELY CONNECTED TO SAID LINKS FOR POSITIVELY LIMITING THE OUTWARD MOVEMENT OF SAID WEIGHTS, SAID MEMBER BEING PIVOTALLY CONNECTED AT ONE END THEREOF TO ONE LINK OF ONE OF SAID PAIRS OF LINKS AND HAVING A SLOT FORMED NEAR THE OTHER END THEREOF, SAID SLOT RECEIVING ONE LINK AND OTHER PAIR OF LINKS.

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