US2683597A - Governor utilizing leaf spring responsive to throw of governor weights - Google Patents

Description

y' 1954 R. J. REEK 2,683,597

GOVERNOR UTILIZING LEAF SPRING RESPONSIVE T0 THROW OF GOVERNOR WEIGHTS Original Filed Aug. 1, 1946 //V|/ENTOR. R074! (A Eff/a jrraR/vsy.

Patented July 13, 1954 UNITED STATES PATENT OFFICE GOVERNOR UTILIZING LEAF SPRING RE- SPONSIVE TO THROW OF GOVERNOR WEIGHTS corporation of Delaware Continuation of application Serial No. 687,780,

August 1, 1946. This a Serial No. 230,215

4 Claims.

This invention relates to speed sensing devices or governors responsive to the speed of its driving apparatus for controlling a mechanism.

This application is a continuation of my application Serial No. 687,780, filed August 1, 1946, now abandoned.

It is an important object of the invention to provide a governor responsive to its driving apparatus for controlling a switch which forms a part of an electrical system.

Another important object of the invention resides in the provision of centrifugally controlled switch.

A further important object of the invention resides in the provision of a centrifugally controlled switch which may be adjusted to vary its opening and closing cycle.

Another object of the invention is to provide a device having these advantages and capacities, and which is, compact, and closely organized in construction, reliable and effective in operation, conveniently adjustable and adapted to be economically manufactured.

Other objects and advantages reside in certain novel features of the construction, arrangement and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference beinghad to the accompanying drawing forming a part of this specification, and in which;

Figure 1 is a view in section of the device of the invention, with parts shown in elevation;

Figure 2 is a view in perspective of the rotating member of the device;

Figure 3 is an elevational view of the rotating member; and

Figure 4 is a modified form of the centrifugally operated mechanism.

Referring to the drawing, reference numeral I designates a housing having a cover [2, secured thereto by screws l4. The housing is formed to provide a boss 16 which is bored at l8 to receive a sleeve 28, recessed at 22 to serve as a bearing for a rotatable shaft 24. The boss is threaded at 25 to enable mounting the housing securely in place. The shaft 24 may be connected, in any suitable manner, to a mechanism, not shown, the speed of which is to be sensed.

The cover I2 carries a single pole double throw switch 28 located interiorly thereof. The switch pplication June 6, 1951,

comprises a blade 30 normally biased downwardly, as viewed in the drawing, toward terminal 32, but urged into contact with terminal 34 by centrifugally operated mechanism 36. The blade 30 is securely held to the cover i2, in any suitable manner, such as by a rivet 38 which also forms a conductor for passing current to the blade 30. A lug 40, into which electrical conductors may be inserted, is held in place to the exterior of the cover by the rivet 38. The terminals 32 and 34 are electrically connected to the exterior of the cover by rivets 42 and 44 respectively. The rivets 42 and 44 engage lugs 45 and 48 respectively at one end and the terminals 32 and 34 at the other end. It should be pointed out that instead of operating the switch 28 the centrifugally operated mechanism could be made to move a lever to operate a valve, not shown, or to move a member, not shown, to start a chain of events which eiTects control of the driving mechanism, not shown.

The centrifugally operated mechanism 36 is suitably fastened to the shaft 24 in any manner, as shown. The mechanism comprises an over center spring or toggle arrangement 50 formed from a U-shaped element having its parallel sides 52 and 54 secured to a base plate 56 mounted on the shaft 24. The U-shaped element is slotted at 58 and 69 to provide a member 62 fixed at both ends to the element and formed to be longer than the length of the slots 58 and 60 to thereby cause the member to bulge or seek an arcuate form. Member 62 is formed in a manner to provide a spring having a negative rate or characteristic. That is, as the sprin is bent downwardly to ward an over center position its resistance to bending decreases. The switch blade 30 carries a button 6!, made of insulating material, and normally is in contact with the member 62, whereby the blade is held out of contact with the terminal 32 and in contact with the terminal 34. In the present invention the member 62 is deflected downwardly at its center under the centrifugal action of weights 64 and 68 which are clamped or otherwise fixed to the member 62. These weights are suspended from the member 62 with their pivot points offset radially from the axis of rotation of the shaft. The bias of the spring-like member 62 is such that the bulge is normally in the direction shown in the drawing,

Figures 1 and 2. The base plate 55 is cut out at 38 and is to accommodate the ends of the suspended weights B4, and 66 which are drilled and tapped at 1'2 and M to receive adjusting screws 16 and '58 to vary the center of gravity of the Weights and consequently the length of their moment arms. This adjustment varies the centrifugal force applied by the weights for moving the member 62 from the position shown in Figure 2 to that shown in Figure 3 and, therefore, controls the high speed at which the governor responds. Adjusting screws 30 and 82 are diametrically disposed in the parallel sides of the U-shaped element in a mannerto limit the outward swing or throw of the weights to thereby control the speed range of the mechanism. That is, since the radius of gyration of the weightsincreases as they move away from ,the'center of rotation in response to a predetermined shaft speed it follows that the shaft speed must be rereduced below said predetermined speed to allow the weights to return. The: amount of reduction in shaft speed below said predetermined value will, of course, depend upon the increase-inradius of gyration or the distance the Weights have moved out from their center of rotation and the characteristic of the spring-like member, 62. To increase the speed range of the governor, screws and 82 are turned outwardly with respect to the sides 52 and 3 and .vice Versa to decrease the speed range. This adjustment controls the low speed at which the governorresponds. It will thus be noted that either adjustment independently controls the speed range, that is, the overall speed range of the governor. Stating it another way, either adjustment will vary the differential between high and low governor speeds.

The relationship between the blade. 38 and the member are is such that when the member reaches a lrinematically unstable condition there will still remain a substantial contact pressure between the blade 38 and the contact'34.. This prevents fluttering of the blade 39 and hence eliminates premature making and breakingof the contacts.

Figure 4 illustrates a modified form of the centrirugally operated mechanism compri g a supporting element 36 having abase 92 'Wlbl'l a boss Bil adapted to lit the shaftj2 l to. securely fasten the mechanismthereto. The base 92 has sides 96 and 98 integral therewith and notched at iilil and it? to receive the ends of a preformed spring-like member as; having a negative rate. The weights E i and 66 are suspended from the member 564 in any suitable manner, as shown. Due to the centri ugal action of the weights when the shaft rotates at predetermined speeds, the spring 534 is flexed downwardly. A tension ing screw E66 passes through side 95 andthreadedly engages side 98. to thereby hold the-sides relatively rigid. The screw also provides .adjusting means for varying the actuating force of spring we upon the blade 36. The springlii l has a diminishing rate characteristic, which can be varied by. adjusting means shown in the form of a threaded bolt or red ice, connecting the sides or side portions 96 and 93 of the U- haped member 96. By adjusting the bolt or rod N36 to decrease the spacing of the sidestli and GS of U-shaped member, the spring rate of the leaf spring its may be increased, the opposite effect resulting from an increase in the spacing of said sides or side portions 96 andefi. .Changing the rate characteristic of the .spring .564 varies the speed range of thedevice.

Operation. and adjustment of. the. mechanism is as follows: With the parts in the position shown in Figures 1 and 2, screws it and it are adjusted, so that at a preselected speed of the driving shaft 2:3, the weights will cause the 5 member 62 to assume the position shown in Figure 3, at which time, an electrical connection is made between the blade 36 and contact This adjustment takes care of the up speed of the governor. After selecting the down speed or speed range desired the screws as and 32 are adjusted. If for example, it is decided to increase the speed range, that is, make the switch operate at a lower governor speed from that shown in Figure 1, screws=3ii and 82 would be turned outwardly to thereby allow a greater radius of gyration of the weights.

Although this invention has been described in connection with certain specific embodiments, principles are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

-Having thus described the various features of the invention, what I claim as new and desire to secure by LettersPatent is:

1. A speed sensing device comprising a rotatable element, meanscontrolled by the speed of the element within apredetermined speed range, centrifugally actuated means mounted for rotation by said element and comprising a U shaped member having spaced side portions, a .leaf spring suspended .by. its. ends on the side portionsof said U-shapedmember in a manner such as to provide said spring with a diminishing rate characteristic, said spring being arin operative relationship with said first named means, a pair of Weights, one carried. on each end of said spring adjacent the points of r0. suspension,v and an. adjustable connection be tween the sides of the U-shaped member for changing the rate characteristic of the spring.

2. A speed sensing device. comprising a rotatable element, means controlled by the rota- 5 tional speed of. the element within a predetermined speed range, centrifugally. actuated means carried by said elementand respomive to the speed thereof comprising a U-shaped .member having spaced side portions, aleaf spring supportedatits ends between the side portions ofsaid member in a manner to provide said spring with a diminishing rate characteristic, said leaf spring being. arranged in operative relationship with said first namedmeans, a pair of Weights,

one swingably suspended .oneach end of said leaf spring and positionedinside the points of support and contiguous thereto,.. means carried at the free end of each weight forchanging the length of its moment arm, and means connecting so the, side portions of. said U-shaped member for varying the rate characteristic of said leaf spring.

3.. A speed sensing device comprising. a rotatable element, means controlled by the rotational speed of the element within a predeter- 5 mined speed range, centrifugally actuated means to, said portions and located in operative. relationship with. said nrst-namedgmeans, side portions being so spaced as to maintain the spring under compression with .a diminishingratecharacteristic asthe. spring flexes toward dead center,

.75. a..pair of elongated weights-secured to opposite ends of said leaf spring adjacent the points of connection of the spring to said side portions, said weights having radially-outwardly swingable portions depending between the side portions of the U-shaped member, means carried by the swingabie portions of each weight for varying its moment arm, and means supported by the side portions of the U-shaped member for limiting the outward throw of said weights.

4. A speed sensing device as claimed in claim 3 wherein means are provided for adjusting the spacing of the side portions of said U-shaped member to thereby adjust the rate characteristics of said leaf spring.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Crabb Mar. 2, 1920 Tomiinson May 9, 1922 Tomiinson May 9, 1922 Tomlinson Oct. 24, 1922 Parsons Sept. 2, 1924 Sole June 27, 1933 Wright Mar. 4, 1947 Vacha Oct. 28, 1952

Images