US2066989A - Centrifugal device - Google Patents

Description

G. H. LELAND GENTRIFUGAL DEVICE v Filed Sept. 24, 1934 Jan. 5, 1937.

2 Sheets-Sheet l E/EURE'E EL A/\/17.

his/4 W EN :3

' Jan. 5, 1937.

G. H. LELAND CENTRIFUGAL DEViCE Filed Sept. 24, 1954 2 Sheets-Sheet 2 5505 55 LEL 4ND.

6 M54 TTUFf/VEX Patented Jan. 5, 1937 UNETD sra'rss PATENT OFFICE CENTRIFUGAL DEVICE Application September 24, 1934, Serial No. 745,302

21 Claims.

This invention relates to a centrifugal device and is designed more particularly for automatically controlling the starting and running circuits of an induction motor.

One object of the invention is to provide a centrifugal device of compact construction which may be installed and operated in a relatively small space.

A further object of the invention is to provide a centrifugal device which will operate with a snap action and which will offer firm resistance to the pressure of the resilient switch member when the switch is closed.

A further object of the invention is to provide a centrifugal device which will be simple in construction and which can'be produced at a low cost.

A further object of the invention is to provide a centrifugal device of a strong durable construction which is not liable to disarrangernent or injury in service.

Other objects of the invention will appear as the mechanism is described in detail.

In the accompanying drawings Fig. 1 is an end elevation of a motor embodying my invention, partly in section on the line i-l of Fig. 2; Fig. 2 is a staggered horizontal section taken on the line 22 of Fig. 1; Fig. 3 is a vertical section taken on the line 3-3 of Fig. 1; Fig. 4 is a sectional detail View of a portion of the centrifugal device, showing the weight in its outermost position; Fig. 5 is a similar view showing the weight in its retracted position; Fig. 6 is a detail view of one of the levers of the centrifugal device; and Fig. 7 is a detail view of the cushioning device.

In these drawings I have illustrated one embodiment of my invention and have shown the same as applied to an induction motor but it will be understood that the invention may take various forms and may be used in connection with motors or other devices of various kinds.

In the particular embodiment here illustrated the motor comprises end frames, one: of which is shown at IU, which support the stator l I and the rotor l2 of the motor, the shaft 13 of the rotor being journaled in bearings l4 carried by the end frames. As is customary in induction motors the stator is provided with separate starting and running circuits and these circuits are automatically controlled in accordance with the speed of the motor by means of a suitable switch which is here shown as comprising a stationary contact member 2|, carried by a terminal block 15, and a movable contact member 29 carried by a resilient arm 28 which is supported on the terminal block,

as shown at 2B and extends across the rotor shaft I3.

The switch member 28 is automatically actuated to close the starting circuit when the rotor is stationary or moving at low speed and to open that circuit when the motor attains normal high speed, this being accomplished by a suitable centrifugal device. The centrifugal device here shown is of a simple inexpensive construction and is highly efficient in operation. It comprises an actuating member, such as a collar 4|, slidably mounted on the rotor shaft l3 and having at one end thereof a circumferential flange 42 arrange to engage the switch member 28. This actuating member or collar is provided in opposite sides, adjacent to the flange, with notches 43. The actuating member is of insulating material and to facilitate the molding thereof the notches are formed by molding in the collar longitudinal openings 44 which extend through the flange adjacent to the shaft and for a short distance into the body of the collar beyond the shaft, these last mentioned portions of the openings extending entirely through the body of the collar and thus providing the desired notches. In order to impart greater depth to the notches I prefer to form on the body of the collar at the end of each opening a radial projection 45.

Levers 4i; are arranged on opposite sides of the actuating member, and have their inner ends seated in the respective notches 43, these notches being of sufficient width to permit of the free pivotal movement of the levers therein. The levers have their outer ends weighted, in the present instance by providing the same with metallic rollers 41, and these weighted ends of the levers are guided in substantially radial paths so that as the weighted ends of the lever move toward and from the shaft the inner ends of the lever, and the actuating device with which they are connected, will be moved lengthwise of the shaft. In the construction shown each lever comprises a transverse portion 48 having a lip 49 to enter the corresponding notch in the collar and arms 50 extend from the respective ends of the transverse portion 48 lengthwise of the shaft and toward the rotor and have their end portions extending outwardly from the shaft. These end portions are provided with apertures 5! to receive the pintles or shaft 52 of the corresponding weight. Each arm of the lever has near its outer end laterally extending lugs 53 and the corresponding lugs of the two levers are connected one to the other by springs 54 which resist the outward movement of the weights by centrifugal force and serve to move the weights toward the shaft when the centrifugal force ceases.

The weights may be guided in radial paths by any suitable means but, in the present construction, I have mounted on the shaft, adjacent to the rotor, a transverse member 55 which extends for some distance beyond the opposite sides of the shaft and has its end portions bent inwardly, as shown at 56, and spaced from the body of the transverse member to provide guideways in which the weights or rollers are mounted for radial movement. The inwardly turned parts 56 of the guide members extend between the arms 50 of the levers so as to cause the levers and their weights to rotate with the shaft, to which the guide member is rigidly secured. As shown in Figs. 3 and 4 the weights and levers are in the positions which they occupy when the motor is running at normal speed and the starting circuit is open. When the motor slows down or stops the springs 54 will move the weights inwardly in radial paths, thus causing the inner ends of the levers to move the actuating device away from the rotor and into engagement with the switch member 28, thereby closing the starting circuit, as shown in Fig. 5.

The arrangement of the centrifugal levers and weights is such that when the weights are in their innermost positions, and the switch closed, as shown in Fig. 5, the points of connection of the centrifugal springs with the levers will be spaced a considerable distance from the axes of the levers and will offer a maximum of resistance to the outward movement of the weights. As the weights move outwardly the points of connection of the springs with the levers approach over center positions with relation to the respective axes and move in approximately straight lines so that the resistance of the springs to the final movements of the weights is relatively small. Hence the weights will be retained in their innermost positions until the centrifugal force is sufficient to overcome the tension of the springs 54 and will then move quickly to their outermost positions, with what is in effect a snap action. Likewise when the weights begin their inward movement the pull of the springs will increase as the weights move inwardly to quickly complete that movement. If the switch starts to open, due to a temporary slowing down of the motor, it is quickly returned to its closed position. This construction eliminates all fluttering of the switch, which is highly objectionable, particularly in a motor of the type here shown where it is destructive to the motor starting mechanism and reduces the pick-up power of the motor.

The centrifugal mechanism is of such a character as to impart to it a toggle action which serves to hold the switch closed against the action of the resilient switch member or spring 28. It will be noted that when the centrifugal weights are in their innermost positions, as shown in Fig. 5, the axis of the lever, the axis on which the weight is connected with the lever, and the point of contact of the weight with the guide member 55 are almost in line and will offer a very substantial resistance to the outward movement of the switch actuating member 4|, independently of the centrifugal springs 54. The switch actuating member is thus held firmly in a position to hold the switch closed and to prevent the pressure of the switch member or spring 28 from moving the actuating member outwardly. In production it is very difllcult to provide switch members or springs 28 which are absolutely uniform in tension and unless some means other than the centrifugal springs are provided for holding the actuating member against outward movement it is necessary that the centrifugal springs 54 be of sufficient strength to overcome the maximum pressure of the switch member. With the present construction the switch members may vary greatly in resilient strength without any likelihood of the pressure thereon imparting movement to the switch actuating member and the springs may be of light tension and the weights of light weight without danger of outward movement being imparted to the weights by the switch member or spring, and a variation of the strength of the switch springs will have no effect on the cut-out speed of the motor.

The centrifugal device is of such a construction as to practically eliminate all noise from its operation and to accomplish this I have provided cushioning devices to gradually check the movement of the switch actuating member or collar toward the rotor and to gradually check the movement of the weights toward the shaft. The guideways for the weights are of a length slightly greater than the maximum outward movement of the weights. Consequently the weights do not engage the ends of the guideways but their outward movement will be limited by the interruption of the movement of the actuating collar 4!. The cushioning means comprises a collar or band 51 of resilient metal mounted about the shaft and rigidly secured to the transverse member 55. This collar is provided on each side of the shaft with a pair of resilient fingers 58, the end portions of which are curved away from the transverse member 55 and extend into the paths of the weights 41. Those portions of the collar 5'! lying between the fingers of the respective pairs are bent outwardly, as shown at 59, to provide the same with resilient portions lying in the path of the actuating collar 4!. Hence as the collar moves toward the rotor it will engage the resilient portions 59 which will gradually check and cushion the movement thereof. When the weights move inwardly toward the shaft they will engage the resilient fingers 58 and their movement will be gradually checked.

It will be apparent from the foregoing description that the centrifugal device is of a very simple compact construction and that it may be mounted and operated in a comparatively small space, due to the character and movement of the weights. At the same time the construction is of a very strong durable character and there islittle likelihood of the parts being disarranged or injured in the operation of the motor. Due to the simple character of the parts and the case with which they may be assembled the device as. a whole may be produced and installed at a low cost.

While I have shown and described one embodiment of my invention I wish it to be understood that I do not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In combination with a rotatable structure, centrifugal mechanism comprising a member mounted for movement lengthwise of the of said structure, a plurality of substantially radial arms connected with said structure for rotation therewith, and having their outer portions turned inwardly and spaced from the inner portions thereof lengthwise of the of said structure to form guideways, a plurality of levers pivotally mounted on said movable member and having arms extending lengthwise of said axis, rollers carried by said arms and mounted in the respective guideways, and yieldable means for resisting the outward movement of said arms.

2. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, a device connected with said shaft for rotation therewith and having near one limit of movement of said slidable member a plurality of substantially radial guideways, the inner ends of which are spaced from said shaft and overhang the path of said slidable member, a plurality of levers pivotally mounted on said slidable member near that end thereof opposite said device and having arms extending toward said device and provided with parts mounted for movement in the respective guideways, and yieldable means for resisting the outward movement of said arms.

3. In combination with a rotatable structure, a centrifugal mechanism comprising a member mounted for movement lengthwise of the axis of said rotatable structure, a plurality of levers pivotally connected with said member at points spaced about the same and having their outer end portions spaced from said pivotal connections lengthwise of the axis of said rotatable structure, weights pivotally mounted on said outer end portions of said levers, substantially radial guides for said weights rigidly connected with said rotatable structure, each lever and its weight being so arranged that when said weight is in its innermost position the pivotal axis thereof will be approximately in line with the pivotal axis of said lever and the point of contact of the weight with its guide.

4. In combination with a rotatable shaft, centrifugal mechanism comprising a member slidably mounted on said shaft, a device connected with said shaft for rotation therewith and having on a plurality of sides of said shaft parts spaced one from the other lengthwise of said shaft to form substantially radial guideways, levers pivotally connected at their inner ends with said slidable member and having outer portions extending lengthwise of said shaft, circular weights rotatably mounted on the outer portions of said levers and mounted in the respective guideways for bodily movement, each lever and its weight being so arranged that when said weight is in its innermost position the axis of rotation of said weight will be adjacent to a line extending through the point of contact of said weight with its guideway and through the pivotal axis of said lever.

5. In combination with a rotatable shaft, centrifugal mechanism comprising a member slidably mounted on said shaft, a device connected with said shaft for rotation therewith and provided on a plurality of sides of said shaft with guideways, Weights mounted in the respective guideways, levers pivotally connected at their outer ends with said weights and pivotally connected at their inner ends with said slidable member, and yieldable means to resist the outward movement of said weights, said levers and said weights being arranged to operate as a toggle to resist the movement of said slidable member in one direction.

6. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, a device connected with said shaft for rotation therewith and having on a plurality of sides of said shaft parts spaced one from the other lengthwise of said shaft to form substantially radial guideways, weights mounted in the respective guideways, levers connected at their outer ends with said weights and pivotally connected. at their inner ends with said slidable member, said levers having parts engaging said device to retain said weights in said guideways and to cause said levers to rotate with said shaft, and yieldable means to resist the outward movement of said weights.

'7. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, a device connected with said shaft for rotation therewith and having on a plurality of sides of said shaft parts spaced one from the other lengthwise of said shaft to form substantially radial guideways, weights mounted in the respective guideways, levers comprising outwardly extending parts pivotally connected at their inner ends with said slidable member and each having arms extending lengthwise of said shaft, connected with the corresponding weight and embracing a part of its guideway to retain said weight in said guideway and to connect said arms with said shaft, and yieldable means to resist the outward movement of said weights.

8. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, said slidable member having a plurality of radial notches spaced about the same, levers having portions loosely seated in the respective notches for pivotal movement with relation to said member and extending outwardly therefrom, each lever having another portion extending lengthwise of said shaft, weights connected with the last mentioned portions of said levers, a device connected with said shaft for rotation therewith, held against axial movement and having parts forming substantially radial guideways in which the respective weights are mounted, and yieldable means to resist the outward movement of said weights.

9. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft and having a plurality of notches in the exterior surface thereof, a plurality of substantially radial arms connected with said shaft for rotation therewith and held against axial movement, each arm having its outer portion turned inwardly and spaced from the inner portion thereof lengthwise of said shaft to form a guideway, a plurality of levers each having a part loosely mounted in one of the notches of said slidable member for pivotal movement therein and extending outwardly therefrom and also having arms extending from the respective sides of said part lengthwise of said shaft, rollers rotatably supported between the arms of said lever and mounted in one of said guideways for bodily movement therein, and yieldable means to resist the outward movement of said levers.

10. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft and having a plurality of notches in the exterior surface thereof, a plurality of substantially radial arms connected with said shaft for rotation therewith and held against axial movement, each arm having its outer portion turned inwardly and spaced from the inner portion thereof lengthwise of said shaft to form a guideway, a plurality of levers each having a part loosely mounted in one of the notches of said slidable member for pivotal movement therein and extending outwardly therefrom and also having arms extending from the respective sides of said part lengthwise of said shaft, rollers rotatably supported between the arms of said levers and mounted in the respective guideways for bodily movement therein, the arms of each lever being arranged to engage a part of the corresponding guide arm to cause said' lever and said slidable member to rotate with said shaft, and yieldable means to resist the outward movement of said levers.

11. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, levers pivotally connected with said slidable member and extending outwardly therefrom, centrifugal weights connected with the outer ends of the respective levers, means rotatable with said shaft for guiding said weights in substantially radial paths, yieldable means to resist the outward movement of said weights, and yieldable means near the inner ends of said paths to cushion the final inward movement of said weights, and yieldable means to cushion the final movement of said slidable member by said weights.

12. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, levers pivotally connected with said slidable member and extending outwardly therefrom, centrifugal weights connected with the outer ends of the respective levers, a device rotatable with said shaft and having parts forming substantially radial guideways for said weights, yieldable means for resisting the outward movement of said weights, and a cushioning device mounted in a fixed position with relation to said shaft and having yieldable parts arranged in the path of said weights as the latter move inwardly.

13. In combination with a rotatable shaft, a centrifugal mechanism comprising member slidably mounted on said shaft, levers pivotally connected with said slide-bio me. her and extending outwardly therefrom, centri a1 weights connected with the outer ends of the respective levers, a, device rotatable with said shaft and having parts forming substantially radial guideways for said weights, yieldable means for resisting the outward movement of said weights, a collar mounted in a fixed position about said shaft and having a yieldable part arranged in the path of said slidable member.

14. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, lovers pivotally connected with slidable member and extending outwardly therefrom, centrifugal weights connected with the outer ends of the respective levers, a device rotatable with said shaft and having parts forming substantially radial uideways for said weights, yieldable means for resisting the outward movement of said weights, and a collar mounted about said shaft, having resilient fingers extending into the paths of said weights and having resilient portions between said fingers and arranged in the path of said slidable member.

15. In combination with a rotatable shaft, a centrifugal mechanism comprising a member slidably mounted on said shaft, said slidable member comprising a body portion and a flange at one end of said body, said member having axial openings extending through said flange and into said body and said body having projections at the ends of said openings to form notches, levers having their inner ends seated in said notches, centrifugal weights connected with said levers, means to cause said levers and said weights to rotate with said shaft, and yieldable means to move said weights toward said shaft.

16. In combination with a rotatable shaft, an annular member slidably mounted on said shaft, levers pivotally connected with said member near one end thereof, extending lengthwise thereof and terminating at points near the other end of said member, weights connected with the free ends of said levers, substantially radial guides for said levers connected with said shaft for rotation therewith and having means to cause said levers and said weights to rotate with said shaft, said guides having their inner ends spaced from said shaft and arranged to overhang said annular member when the latter is at one limit of its movement, and yieldable means to resist the outward movement of said weights.

1?. In combination with a rotatable shaft, a centrifugal mechanism comprising an annular member mounted on said shaft for movement lengthwise thereof, a device rigidly connected with said shaft beyond but adjacent to one limit of movement of said annular member and having a plurality of parts spaced about said shaft and forming substantially radial guides, said guides being arranged in a transverse plane intersecting said shaft between the limits of movement of said annular member and having their inner ends spaced from said shaft to permit a part of said annular member to move into the plane of said guides, a plurality of levers having their inner ends pivotally connected with said annular memher and having their outer ends weighted and connected with the respective guides for radial movement thereon, and spring means for moving the weighted ends of said levers inwardly.

18. In combination with a rotatable shaft, centrifugal mechanism comprising an annular member mounted on said shaft for movement lengthwise thereof, a plurality of substantially radial guides connected with said shaft beyond but adjacent to one limit of movement of said annular member, each guide comprising two parts connected one to the other at their outer ends and spaced one from the other lengthwise of said shaft to form between them a guideway the plane of which intersects said shaft between the limits of movement of said annular member, the inner end of one part of each guide being spaced from said shaft to permit said annular member to enter the space between the same and said shaft, a plurality of weighted levers pivotally mounted on said annular member and having at their outer ends parts movably mounted in the respective guideways, and yieldable means to resist the outward movement of said weighted levers.

19. In combination with a rotatable shaft, centrifugal mechanism comprising an annular member mounted on said shaft for movement lengthwise thereof, a plurality of substantially radial guides connected with said shaft for rotation therewith and arranged in a transverse plane intersecting said shaft near one limit of movement of said annular member, said guides having their inner ends spaced from said shaft to permit said annular member to enter the space between said guides and said shaft, a plurality of weighted levers having their inner ends pivotally connected with said annular member near that end thereof remote from said guides and having their outer ends slidably connected with the respective guides, and spring means for moving the outer ends of said guides inwardly.

20. In combination with a rotatable structure, a centrifugal mechanism comprising a member mounted for movement lengthwise of the axis of said rotatable structure, a device connected with said structure for rotation therewith and having on a plurality of sides of the axis of said structure parts forming substantially radial guides arranged in a plane which intersects said axis between the limits of movement of said member, a plurality of levers each having a part pivotally mounted on said movable member and extend ing outwardly therefrom, and arms extending from said part lengthwise of the axis of said structure, weights supported by the arms of said levers and connected with the respective guides for movement thereon toward and from said axis, and yieldable means to resist outward movement of said weights.

21. In combination with a rotatable structure, a centrifugal mechanism comprising a member mounted for movement lengthwise of the axis of said rotatable structure, a device connected with said structure for rotation therewith and having on a plurality of sides of the axis of said structure parts spaced one from the other lengthwise of the axis to form substantially radial guideways arranged in a plane intersecting said axis between the limits of movement of said member, a plurality of levers each having a part pivotally mounted on said movable member and extending outwardly therefrom, and arms extending from said part lengthwise of the axis of said structure and having outwardly extending ends, rollers carried by the ends of said arms and mounted in the respective guideways for bodily movement toward and from said axis, and yieldable means to resist the outward movement of said levers and said rollers.

GEORGE H. LELAND.

Images