US1911964A - Centrifugal switch - Google Patents

Description

y 1933. w. .1. PASINSKI I 1,911,964

CENTRIFUGAL SWITCH Original Filed Feb. 1a, 1928 2 Sheets- Sheet 1 INVENTOR ATTORNEYS so the position of the parts 85 ature sha t w safety clutch 16 to a driving worm 17 is eld in adjuste Patented May 30, 1933 UNITED STATES wanna J. rasmskr, or nn'moir, mronmm,

MACHINE 00mm, or nnraorr, mcmean,

assronoa 'ro mmnoncns mute a conrolwrron or memes! OENTBIFUGAL SWITCH Original application fled February 18, 1928, Serial No. 254,077, now Patent 110. 1,857,790, dated In! 10, 1988. Divided and this application died October 1, 1981. Serial 80. 569,288.

This invention relates to a centrifugal switch, the present application being a division of my co-pendmg application, Serial No. 254,677, filed February 16, 1928, now Patent No. 1,857,790, for a speed controlling mechanism. 1

The speed controlling mechanism of said application is primarily designed to govern the speed of a small series motor used to drive calculating machines and the switch of the present application is particularl useful in this environment where a sma sensitive switch is required that is responsive to the speed of a motor.

- The general object of the invention is to provide an improved centrifugal switch.

Other objects and advantages of the invention will appear from the following specification and drawings.

An embodiment of the invention is shown in theaccompanying drawings in wh1ch:--

s viewof'a speed governor with the switch ap lied thereto. p Fig. 2 is an enlarged section and plan view of the switch showing the position of the parts when the switch is closed to start the motor and before the switch has started rotating.

Fig. 3 is a view similar to Fig. 2 showing with the switch open while it is being rotated.

The switch is driven by an electric motor whose s dis to begoverned. The arm- 11 of this motor is connected by a coupling 12 to a drive shaft 13 journaled in a sleeve 14 screw threaded into a housing 15 that encloses the driving connections. The shaft 13 is connected'through afripitiorai xe to av shaft 18 journaled in the housing 15. The driving friction of the safety clutch 16 is maintained b a spring 19 whose tension ma be adjuste b means of a nut 20 that position by a lock nut 21. The clutch 16 provides a connection in the driving train t at will slip to prevent breakage in the event any (part of the mechanism should become locke or jammed. The

50 worm 17 meshes with a worm wheel 22 fixed re 1 is a horizontal section and plan to a driving clutch member 23 journaled loosely on a shaft 24 which, in turn, is journaled in the housing 15. Positioned for 00- operative engagement with the driving clutch member 23 is a driven clutch member 26 having teeth adapted to mesh with the teeth of member 23. The member 26 is in the form of a sleeve slidably mounted on the shaft 24. A lever 27 pivoted at 28 to a bracket 29 attached to housing 15 is employed to open and close the switch to start 7 and stop the motor.

When the motor is at rest and the clutch is in open position, the parts occupy the position of Fig. 1, whereit will be observed that the lever 27 holds the switch open. When the clutch is engaged the member 27 is rocked counterclockwise from the position of Fig. 1 so as to release the switch to permit it to close and to free it for opening and closing as will be presently described.

Fixed to a reduced portion 18 is a circular race member in the form of a disk having anannular raceway 41 in one of its faces. The outer edge of'this raceway is inclined as indicated at 42. Positioned within the raceway are a lurality of balls 43, maintained in spaced re ation by spacers 44. Positioned below the raceway for en agement by carrie by a sleeve 46 slidably and rotatabl mounted on the reduced end 47 of the sha 18. The disk is rotated with the disk 40 by means of a connecting pin 48 fixed to the disk 40 and rojecting into an opening in the disk 45. e lower end of the sleeve 46 is cup-shaped and it fits over a ball 49 which is rotatably mounted in the cupped end of an adjustin screw 50. This provides a ball hearing or sleeve 46. The screw- 50 is threaded into an insulating washer 51 carried by one end of a lever. 52 pivoted at 59 to an arm 54 projecting from the stationary bracket 29 whose u per end is attached to the housing 15. it is to be observed that the bracket' 29 is insulated from housing 15 by a washer 57 between the bracket and housing. The other end of lever 52 has a raised portion 58 positioned to contact one arm 59 of a bell crank lever pivoted the balls 43 is a disk 45.

30 of the shaft at 60 on the arm 54. The other arm 61 of the bell crank lever carries an electrical contact 62 adapted to engage companion stationary contact 63 mounted in an insulating bushing 64 in the support 29. The bell crank lever 5961, with its contact 62 is urged in a clockwise direction by a spring 65 connected at one end to the arm 61 and at its other end to an L-shaped member 66 carried by an adjusting screw 67 threaded into the support 29 and locked in adjusted position by'a nut 68. The arm 61, which is made of conducting material, is electrically connected through its pivot with a line con-.

ductor 69, and the contact 63 is electrically connected to one of the main motor leads 70 so that one side of the current supplied to the motor is controlled by the contacts 62-63. In order to reduce sparking between the contacts, a condenser, not shown, is connected across them, the leads 71 and 72 to the condenser being illustrated in Fi 1.

From the above description it will e clear that the spring 65 not only urges the contact 62 toward the contact 63, but it also urges the disk 45 toward the disk 40. The parts are balanced to float so that only a very slight force is required to move them. The operation of the switch is as follows: Assume that the contacts 62 and 63 are in engagement and that the parts occupy the position of Fig. 2 with the controlling lever 27 out of the way so as to permit free movement of arm 61. The main motor circuit is closed and the motor then operates to rotate the shaft 13. This rotates the disk 40 together with the disk 45. The balls 43 tend to move outward by centrifugal force as the speed of the motor increases but they are prevented from moving outward directly by the walls 42 of the disk 40. The centrifugal force tending to move the balls outwardly causes them to move down the inclined walls 42 and push on the disk 45. This tends to move the disk down ward and it, in turn, rocks the bell crank 5961 counterclockwise to move the contact 62 out of engagement with the contact 63 to momentarily break the motor circuit. When the motor circuit is broken the motor no longer has an energy supply and its 5 eed immediately decreases. As the speed ecreases, the centrifugal force on the balls 43 decreases and the spring 65 comes into action to move the parts back toward normal position to close the contacts 62-63. \Vhen the contacts are closed the motor is again energized whereupon it picks up speed and, if there is still a tendency for its speed to increase above the desired amount, the above operation is repeated. The spring 65 may be adjusted so that, at the desired normal speed, the contacts are opened and closed at the given rate. Preferably, this opening and closing of the contacts 62 and 63 takes place rather rapidly and the motor is just supplied with enough energy to keep it at a constant speed.

An important feature of the construction is that the normal or critical speed of the motor may be varied while the motor is running by simply adjusting the set screw 67 which varies the tension of the spring 65 and therefore varies the centrifugal force required to overcome the spring. This alters the time of engagement and disengagement of the contacts 62 and 63 with the result that, by simply turning the set screw 67, different constant speeds may be obtained.

Another advantage is that the switch may be made very small so as to occupy a small space and at the same time it is very sensitive. It does not depend upon the action of one centrifugal weight but employs a large number of balls all of which act to secure the desired results.

I claim:

1. A centrifugal switch comprising a disk-like rotatable member having an annular recess in one of its faces forming a ball race at a substantial distance from the center of rotation of said member, the outer periphery of said recess being inclined relative to the axis of rotation of said member, a plurality of balls in said recess, a rotatable disk adjacent the face of said member having said recess therein, connections between said disk-like member and said disk to cause said disk to rotate with said member, said disk being slidably mounted so as to be movable to and from said member and being urged toward said member, a movable arm carrying a switch contact adapted to engage a stationary switch contact, and connections between said slidable disk and said arm for causing sliding movements of said disk to open and close said switch.

2. A centrifugal switch comprising a rotatable shaft, a disk-like member fixed to said shaft, said member having an annular recess in one of its faces forming a ball race at a substantial distance from the center of rotation of said member, the outer periphery of said recess being inclined relative to the axis of rotation of said member, a plurality of balls in said recess, a disk rotatably and slidably mounted on said shaft and positioned adjacent the face of said disk-like member having said annular recess, a movable arm carrying a switch contact adapted to engage a stationary switch contact, and connections between said slidable disk and said arm for causing sliding movements of said disk to open and close said switch.

3. A centrifugal switch comprising a rotatable disk-like member having an annular recess in one of its faces forming a ball race at a substantial distance from the center of rotation of said member, the outer periphcry of said recess being inclined relative to the axis of rotation of said member, a 1urality of balls in said recess, a rotatable isk adjacent the face of said member having said ball race in it, means connecting sai disk-like member and said disk to cause them to rotate together, said disk being slidably mounted so as to be movable to an from said member, a movable arm carrying a switch contact adapted to engage a stationary contact, connections between said slidable disk and said arm for causing sliding movements of said disk to open and close said switch, a spring urging said sliding member toward said disk-like member and urging said switch to closed position, and means for adjusting the tension of said spring whereby the action of said centrifugal switch can be conveniently regulated while it is operating.

4. A centrifugal switch comprising a rotatable shaft, a disk-like member fixed to said shaft and having an annular recess in one of its faces forming a ball race at a substantial distance from the center of rotation of said member, the outer periphery of said recess being inclined relative to the axis of rotation of said member, a plurality of balls in said recess, a disk slidably and rotatably mounted on said shaft, said disk being 0- sitioned adjacent the face of said mem er having said ball race in it, a sleeve connected to said disk, a movable arm carrying a switch contact adapted to engage a stationary switch contact, aball bearing connection between said arm and the free end of said sleeve, a sprin ur ing said arm in a direction to close sai switch and to move said disk into engagement with the balls in said race, and means for adjusting the tension of said spring whereby the action of said centrifugal switch may be readily reg-- ulated while said switch is o eratin WALTER J'. lASI SKI.

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