US3527905A

US3527905A - Induction switch with adjustment means for independently selecting the clockwise and counterclockwise angular velocities of actuation

Info

Publication number: US3527905A
Application number: US705053A
Authority: US
Inventors: Kaname Doi
Original assignee: Sumitomo Electric Industries Ltd
Current assignee: Sumitomo Electric Industries Ltd
Priority date: 1968-02-09
Filing date: 1968-02-13
Publication date: 1970-09-08
Anticipated expiration: 1987-09-08
Also published as: FR1555961A; GB1205328A

Description

Sept. 8, 1970 KANAME DOI 3,527,905

INDUCTION SWITCH WITH ADJUSTMENT MEANS FOR INDEPENDENTLY SELECTING THE CLOCKWISE AND COUNTER CLOCKWISE ANGULAR VELOCITIES OF ACTUATION Filed Feb. 13, 1968 v 3 Sheets-Sheet 1 /6 I 2 w 5 4/ '-'--4/5 J 4 I 8 5- /3 4 I N :-23, 2 :7

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INDUCTION SWITCH WITH ADJUSTMENT MEANS FOR INDEPENDENTLY SELECTING THE CLOCKWISE'AND COUNTER CLOCKWISE ANGULAR VELOCITIES OF ACTUA'IION Filed Feb. 15, 1968.

v 3 Sheets-Sheet 2 Fig.3

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KA AME 00/ BY (A20 M525 (Ago THEES H13 A TTOEA/fKS United States Patent 3,527,905 INDUCTION SWITCH WITH ADJUSTMENT MEANS FOR INDEPENDENTLY SELECTING THE CLOCKWISE AND COUNTERCLOCK- A'NGULAR VELOCITIES OF ACTUA- Kaname Doi, Ibaragi, Japan, assignor to Sumitomo Electric Industries, Ltd., Osaka, Japan, a company of Japan Filed Feb. 13, 1968, Ser. No. 705,053 Int. Cl. H01h /10 US. Cl. 20061.46 6 Claims ABSTRACT OF THE DISCLOSURE cally induced rotation of the first named rotor with the magnetized rotor.

BACKGROUND OF THE INVENTION This invention relates generally to electrical circuit makers and breakers and more particularly to switches responsive to angular velocity of a shaft.

It is frequently required in a rotary mechanical structure which rotates in both the clockwise and counterclockwise directions, that a portion or the entirety of a control system or circuit be switched when the mechanical structure changes its condition of rotation such as direction and angular velocity. However, such switches presently in existence provide no means to preset the actuation of the electric switch to independently selected clockwise and counterclockwise angular velocities of a shaft.

SUMMARY OF THE PRESENT INVENTION The induction switch of the present invention comprises a magnetized rotor mounted for rotation on a sup port and a movable contact biased to a neutral position and inductively coupled with the magnetized rotor for magnetically induced movement therewith to switch a circuit or actuate an electrical switch and actuator means to move the contact in one direction from its neutral position regardless of the direction of rotation of the magnetized rotor. The induction switch is provided with means to readily adjust the actuation of the electrical switch to a selected angular velocity of the magnetized rotor and is further provided with means to preset the actuation of the electrical switch to independently selected clockwise and counterclockwise angular velocities of the magnetized rotor.

Other objects and advantages appear hereinafter in the following description and claims.

The accompanying drawings show for the purpose of exemplification without limiting the invention or claims thereto, certain practical embodiments illustrating the principles of this invention wherein:

FIG. 1 is a simplified longitudinal cross-sectional view in side elevation of one embodiment of the induction switch of the present invention.

FIG. 2 is a view in front elevation of the induction switch shown in FIG. 1 as seen in the direction indicated by line 22 in FIG. 1.

FIG. 3 illustrates the structure of FIG. \2 in the condition of actuation when the shaft is rotated in the counterclockwise direction.

FIG. 4 illustrates the structure of FIG. 2 in the condition of actuation when the shaft is rotated in the clockwise direction.

FIG. 5 is a diagrammatic sketch illustrating the adjustable dimensions of the apparatus.

FIG. 6 is a schematic diagram of a circuit illustrating one application of the present invention.

FIG. 7 is a schematic diagram of a circuit illustrating another application of the present invention.

FIG. 8a is a detailed longitudinal cross-sectional view in side elevation of one practical embodiment of the present invention.

FIG. 8b is a partial section detailed view in front elevation of the structure shown in FIG. 8a as seen from the left side.

Referring to FIGS. 1 and 2 of the drawings,the induction switch shown has a two piece housing; namely, casing members 1 and 2. Bearing 4' is secured to casing member 1, while bearing 4 is secured to casing member 2, thereby functioning to afford smooth rotation in either direction of rotor shaft 5 which is journaled therein. Reference numeral 3 indicates a cylinder or sleeve made of pure iron secured to casing member 1 in coaxial relationship to rotor shaft 5. A close clearance 10 is provided between non-magnetized coupling or rotor 7 and sleeve 3 thereby forming a magnetic circuit between magnetized rotor or steel piece 36 and sleeve 3.

Magnetized rotor 36 is secured to rotor shaft 5 for rotation therewith. Coupling discs 6 and 6 are secured to and part of coupling or rotor 7. Rotor 7, including discs '6 and 6', is made of non-magnetizable, highly electroconductive material. Rotor or coupling 7 is given close clearances 9 and 10 between the coupling and the magnetized rotor 36 and cylinder 3, respectively. The nonmagnetized rotor made up of the coupling 7 and coupling discs 6 and 6' is supported by

bearings

8 and 8 which permit free rotation relative to the rotor shaft and is prevented from moving axially by means of spacers 11 and 11'.

Actuator contacts or

arms

12 and 13 are secured to coupling disc 6', and pass with clearance through restricting or limit

holes

12' and 13, respectively, provided in casing member 1. Thus, rotor shaft 5 and magnetized rotor 36 can be continuously driven from a power source, while coupling 7, which is positioned in the magnetic field formed by the magnetic line of force between cylinder 3 and magnetized rotor 36, is angularly displaced by an angle of /206, while actuator 13 is disengaged from contact or switch lever 15 and moves to limit point 17 of restricting hole 13.

When the rotor shaft rotates in the direction L, actuator 13 urges switch lever 15 to limit point 17' of restricting hole 13 against the tension of return spring 25 so that switch lever 15 is angularly displaced by the angle of /200, while actuator 12 is disengaged from switch lever 15 and moves to limit point 18 of restricting hole 12'. When the rotation of rotor shaft 5 is stopped,

actuators

12 and 13 as well as switch lever 15 return to their neutral positions respectively, by virtue of the tensional force 25' of return spring 25. Other suitable spring returns may be employed such as the use of a torsion shaft for pivot shaft 14.

As switch lever 15 is angularly displaced in the direction 15', actuating spindle 20 of switch 19 is displaced in the direction indicated by arrow 21, thereby switching the contacting point of movable contact 22'. That is, when rotor shaft 5 is motionless, movable contact 22' is engaged with stationary contact 24', and when rotor shaft 5 is rotated sufficiently to thereby angularly displace switch lever 15 by the set angle in the direction 15', movable contact 22' will engage stationary contact 23'.

Reference numeral 16 indicates a casing cover which is provided for the purpose of preventing dust from entering casing member 1.

FIG. 3 shows the position of

actuators

12 and 13 when the shaft is rotating in the counterclockwise direction L, and FIG. 4 shows the position of the actuators when the shaft is rotating in the clockwise direction R.

FIG. 2 shows the condition of the induction switch when rotor shaft 5 either is motionless or is rotating with magnetic torque insufiicient to give

actuators

12 and 13 the required force necessary to actuate switch 19 by overcoming the force 25' eifected by return spring 25 through switch lever 15. On the other hand, FIGS. 3 and 4 show the condition of the present device in which the rotational speed of rotor shaft 5 is sufficient to apply the necessary torque to the actuators to overcome the action effected by tensional force 25 of return spring 25.

FIG. 3 illustrates the condition wherein rotor shaft 5 is rotated in the counterclockwise direction and the torque given to actuator 13 has overcome the torque applied by tensional force 25 of return spring 25. Switch lever 15 is therefore angularly displaced about the axis of pivot shaft 14 by the action of actuator 13 until actuator 12 reaches limit point 18 of restricting hole 12', so that switch lever 15 moves actuating spindle 20 in the direction 31. Movable contact 22' is therefore engaged with stationary contact 23' by the actuation referred to above.

FIG. 4 shows the condition in which rotor shaft 5 is rotated in the clockwise direction and the torque given to actuator 12 has overcome the torque exerted by the tensional force 25' of return spring 25, thereby angularly displacing switch lever 15 about the axis of pivot shaft 14 by the action of actuator 12 until actuator 13 reaches limit point 17 of restricting hole 13'. Switch lever 15 therefore moves actuating spindle 20 in the direction 21.

Movable contact 22' is thus engaged with stationary contact 23' by this actuation. Switch lever 15 is always displaced in one and the same direction irrespective of the direction of rotation of rotor shaft 5, thereby necessitating only one single switch 19 to be actuated.

FIG. 5 is a diagrammatic view for explanatory purposes and illustrates the fact that the actuation of switch 19 can be adjustably or selectively set to independently chosen values of clockwise and counterclockwise angular velocities of rotor shaft 5.

In a rotary mechanical structure, there may be requirements wherein the operating conditions of the control system of the structure in the motionless condition should be varied from that in the rotating condition thereof, or the switching point of the control system must be made at the same rotational speed in either the counterclockwise or clockwise direction of rotation of the structure, or the rotational speed resulting in the switching point of the control system in either one of the directions of rotation of the structure should be varied from the rotational switching speed of the other direction. FIG. 5 illustrates the fact that the present invention provides the ability of presetting the control system to any of the conditions referred to above within a limited range.

Assuming that:

l =distance between the center of rotor shaft 5 and that of actuator 12,

l =distance between the center of rotor shaft 5 and that of actuator 13,

r =distance between the center of pivot shaft 14 and that of actuator 12,

r =distance between the center of pivot shaft 14 and that of actuator 13,

l =torque given to actuator 12,

t =torque given to actuator 13,

T =torque generated in rotor shaft 5,

M =moment about pivot shaft 14 resulting from torque 112, and

M =moment about pivot shaft 14 resulting from torque Then, the following equations are obtained:

t =T /l 12 12' 1 1 1' 5 t13=T5/l2 i3= 1s' 2="2 2 5 Assuming now that switch 19 is required to be set so as to be actuated at the same rotational speed of rotor shaft 5 in either the counterclockwise or clockwise directions while the moments about pivot shaft 14 generated by actuator 12 and actuator 13, respectively, are made the same amount with each other, it is only necessary to set the values of the factors referred to above as follows:

Then, the following relationship is obtained from the above equations;

On the other hand, it means that, in order to set the actuating point of switch 19 to any desired value depending upon the direction of rotation of rotor shaft 5, it can be achieved by suitably selecting the ratio of r to r as well as that of 1 to 1 The value of torque T produced by the eddy current generated in coupling 7 having the radius a by virtue of the rotation of magnetized steel piece 36 is obtained as follows:

T= oc Xw) /10,!) (dyne-cm.) where:

X=thickness of the wall of the coupling, OL IfidlllS of the coupling,

w=angular velocity of the magnetized steel piece, A area of the magnetic pole,

0=coeflicient of eddy current,

==electrical resistance of the coupling, =magnetic flux.

As clearly seen from FIG. 1, the switching point of switch 19 can be set at an extremely low rotational speed by increasing the torque of coupling 7 while the frictional resistance occurring at bearings 8 and 8' and pivot shaft 14 as well as the mechanical loss in switch 19 are kept at a minimum and, at the same time, by setting tensional force 25' of return spring 25 to a minimum. It is further possible to change the switching time of switch 19 toward the side of higher rotational speed of rotor shaft 5 by suitably increasing the tensional force of return spring 25.

FIG. 6 shows an example of application of the present invention in an electric circuit in which the present invention is utilized together with a relay. FIG. 7 shows an example of the application of the present invention in an electric circuit in which the induction switch is used in series in the circuit. In both of the drawings, reference numeral 60 indicates contacts 22' and 23' of switch 19 in an extremely low rotational speed detector or induction switch. FIG. 6 shows an electric circuit for applying a voltage across load 61 to do work. In this circuit, it is possible to utilize the control circuit in such a manner, that by setting the contacts of electro-magnetic relay 63 to a condition in which they are either closed or opened by the excitation of coil 63 of the electro-magnetic relay, the electric current either flows through control circuit 62-63-61-62 or is cut off when the electric current flows through extremely low rotational speed detector circuit 62-63-60-62, and the electric current flowing through the control circuit is either cut off or caused to flow when the electric current flowing through the extremely low rotational speed detector is cut 01f.

FIG. 7 shows an electric circuit in which the electric current flow therethrough is controlled by switch 19 of the low rotational speed detector. In this circuit, switch 19 of the low rotational speed detector is connected directly in series in the control circuit and the opening and closing operations of switch 19 are set so as to directly coupled with the opening and closing operations of the control circuit.

FIG. 8 shows a practical embodiment of the present invention in detail. FIG; 8a shows the cross-sectional side view of the embodiment and FIG. 8b is an end view thereof.

Reference numeral 101 designates the switch casing and reference numeral 102 designates the rotor casing. Both casings are joined together by means of machine screws 50. Oil impregnated bearings 4' and 4, are fixedly secured to switch casing 101 and rotor casing 102, respectively, thereby assuring the smooth rotation of rotor shaft 5 which is journaled in the bearings. Bearings 4' and 4 also limit the unnecessary axial clearances between rotor shaft 5 and each of the bearings 4' and 4. Reference numeral 3 designates a cylinder made of pure iron and fixedly secured to rotor casing 102 in coaxial relationship to rotor shaft 5. A close clearance is provided between magnetized rotor 36 and non-magnetized rotor 7 thereby inductively coupling rotor 7 with magnetized rotor or steel piece 36.

The non-magnetized rotor or coupling is supported for free rotation by ball bearings 8 and 8' and consists of coupling or rotor discs 6 and 6', coupling 7,

ball bearings

8 and 8, ball bearing retaining plate 35, and actuator 35'. Rotor shaft 5 and magnetized rotor 36 are fixedly joined together 'by the interposition of soft material 36' such that they are held against both rotational and axial movement relative to each other. Coupling disc 6 and ball bearing retainer 35 as well as coupling disc 6' and actuator 35, all of which are made of non-magnetizable material, are held tightly together by means of rivets 37 which are also made of non-magnetizable material. Coupling 7 is made of non-mangetizable, highly electroconductive material and is secured to each of coupling discs 6 and 6 by means of spring pins 38 which also are made of nonmagnetiza-ble material. The rotor assembly consisting of coupling 7 and coupling discs 6 and 6' is supported for free rotation by rotor shaft 5 through

ball bearings

8 and 8 but prevented from moving axially. Spacers 1t1 maintain close axial clearances between the rotors and each of bearings 4 and 4' so that the rotor shaft is supported for unin' hibited rotation by the bearings. The driving of rotor shaft 5 is facilitated by connector 51 with a key hole therein and is press-fitted in a hole machined in the end surface of rotor shaft 5.

Magnetized rotor or steel piece 36 is coaxial with coupling 7 with close clearance 9 being held therebetween.

Poles or

arms

12 and 13 of actuator '35 pass with clearance through elongated holes 12' and 13', respectively, provided in switch casing 101. Each of these poles is limited in its permissible angular movement by abutments or ends 18 and 17' or 18 and 17 of the respective elongated holes 12 and 13', depending upon the direction of rotation of the non-magnetized rotor or coupling 7.

Oil retainer 40 is detachably secured to switch casing 101 by means of machine screws 45. The oil is supplied from oil impregnated cotton material 41 received in the recess of retainer 40 to oil impregnated bearing 4. Similarly, lubricating oil is retained in oil cup 39 forcibly fitted in the oil supplying hole in rotor casing 102, so that the oil is supplied from oil cup 39 to oil impregnated bearing 4.

Switch lever or contact is mounted for free rotation on pivot shaft 14 which is press-fit in a hole in switch casing 101. Contact 15 is located adjacent to one side of

poles

12 and 13 of actuator 35, actuating spindle of switch 19 engaging the side of the lever or contact opposite to that where

poles

12 and 13 are located. Adjusting spring 32 and return spring are anchored to switch lever 15 at opposite sides of the axis of rotation about pin 14. Both of these springs urge the switch lever 15 toward the same side. In other words, they oppose each other about pin 14.

Adjusting spring 32 is adjustable to eliminate fluctuations and provide positive actuation of actuating spindle 20 of switch 19. The load of the spring 32 may be adjusted by angularly moving spring hanger 33 about the axis of locking screw 34.

Return spring 25 serves to restore mechanical contact 15 to its neutral position after it has been angularly dis placed by the action of pole 12 or pole 13 of actuator 35 and the rotational speed of rotor shaft 5 has reduced to the preselected switching value. Reference numeral 28 designates the coarse adjustment screw threadedly fitted to switch casing 101, and reference numeral 31 designates the locking nut for use therewith. Reference numeral 27 designates the fine adjustment screw, and

reference numerals

30 and 29 designate snap rings, respectively. Snap ring 30 is adapted to afford a restriction to the freedom of the axial movement of fine adjustment screw 27 with respect to coarse adjustment screw 28 and, at the same time, renders the fine adjustment screw to be freely rotated relative to the coarse adjustment screw. Snap ring 29 serves to prevent sliding hanger 26 from being withdrawn from fine adjustment screw 27 by the rotation thereof. The load to be set to return spring 25 which is anchored with its ends to a sliding hanger 26 and switch lever 15, respectively, can be freely varied by moving the sliding hanger 26 either in one direction indicated by arrow 25 or the opposite by rotation of coarse adjustment screw 28 and fine adjustment screw 27.

Switch 19 is secured to switch bracket 44 by means of machine screws 52. Switch bracket 44 is in turn mounted on switch casing 101 by means of machine screws 42 and 43. The hole through which machine screw 43 passes in switch bracket 44 is elongated so that a small amount of displacement of switch bracket 44 about the axis of machine screw 42 in either direction, indicated by arrows 43' and 43", can be effected. This permits the contact pressure of actuating spindle 20 of switch 19 against switch lever 15 to be properly adjusted. This is necessary in order to increase the sensitivity of the opening and closing characteristics of the electric circuit including wire 22 and wire 24 as the opening and closing of the electric circuit is effected by the fine displacement of actuating spindle 20 in the direction indicated by arrow 21.

Reference numeral 46 designates a grommet made of electrically non-conductive material, and it serves to protect

wires

22 and 24 extending from the interior of the casing. FIG. 8b shows that the casing is provided with blind plugs 47 and 48 which permit inspection or location of switch 19, switch lever 15, spring hanger 33, adjustment screws 27 and 28, sliding hanger 26, adjusting spring 32 and return spring 25.

Reference numeral 16 designates a cover which serves to prevent dust from entering the interior of switch casing 101. The cover is secured to switch casing by means of machine screws 16'.

Torque is magnetically induced in coupling 7 tending to rotate it in the same direction of rotation as magnetized rotor 36 by virtue of the eddy currents generated in coupling 7 and produced between magnetized rotor 36 and cylinder 3 by the rotation of the former when rotor shaft 5 is driven by connecting a power source to connector 51 in any known manner. When the torque generated in

actuator pole

12 or 13, secured to coupling 7, overcomes the tensional force of return spring 25,

actuator poles

12 and 13 move angularly in

elongated holes

12' and 13, respectively, until they reach abutments 17' and 18 if rotor shaft '5 rotates in the direction L or ends 17 and 18' if rotor shaft 5 rotates in the direction R. Switch lever 15 is thereby angularly displaced about the axis of pivot shaft 14 so that actuating spindle 20 of switch 19 is urged in the direction indicated by arrow 21 thereby opening the connection between

wires

22 and 24 of the electric circuit. When the rotational speed of rotor shaft 5 decreases and the torque generated in

actuator pole

12 or 13 becomes less than the tensional force of return spring 25, switch lever 15 causes actuator

poles

12 and 13 to return to the initial or neutral positions illuustrated, and actuating spindle 20 is released in the direction opposite to that indicated by arrow 21 to close the connection between

contacts

22 and 24. The electrical control of the rotary mechanical structure can be altered when the rotational speed of the rotor shaft increases or decreases beyond the preselected value.

The rotary induction switch of the present invention can easily be adapted to close a circuit when the rotor shaft moves from a standstill condition to a rotating condition, or from a rotating condition to the standstill condition, or when the rotational speed is increased or decreased beyond a desired preselected rotational speed.

Any suitable rotor combination may be employed to provide the magnetized rotor and the inductively coupled non-magnetized rotor. The rotors need not necessarily be positioned coaxially one over the other. The rotors may be positioned end to end as is commonly done for other applications or apparatus.

I claim:

1. An induction switch operable with angular displacement of a shaft, comprising an electrical switch, a support, a magnetized rotor mounted for rotation on said support, and a movable contact biased to a neutral position and inductively coupled with said magnetized rotor for magnetically induced movement therewith from said neutral position to actuate said switch, actuator means to move said contact in one direction from said neutral position regardless of the direction of rotation of said magnetized rotor, and means to preset the actuation of said switch to independently selected clockwise and counterclockwise angular velocities of said rotor.

2. An induction switch operable with angular displacement of a shaft, comprising an electrical switch, a support, a magnetized rotor mounted for rotation on said support, a second rotor inductively coupled with said magnetized rotor for magnetically induced rotation therewith, a contact lever pivotally secured to said support and biased to a neutral position, and actuator contact means secured to and protruding from said second rotor and operable upon a preselected magnitude of angular displacement thereof in either direction to rotate therewith to engage and pivot said lever in one direction to actuate said switch.

3. The induction switch of claim 2 characterized by means to preset the actuation of said switch by said lever to independently selected clockwise and counterclockwise angular velocities of said magnetized rotor.

4. An induction switch operable with angular displacement of a shaft, comprising an electrical switch, a support, a magnetized rotor mounted for rotation on said support, a second rotor inductively coupled with said magnetized rotor for magnetically induced movement therewith, a pair of actuator contacts extending in the axial direction from one end of said second rotor and aligned on a common diameter thereof with the axis of rotation disposed therebetween, a lever pivotally mounted on said support about an axis parallel with the axis of said second rotor, spring means urging said lever to a neutral position with one edge thereof in engagement with both of said contacts, said lever being displaceable upon induced movement of said second rotor to actuate said switch.

5. The induction switch of claim 4 characterized in that said spring means is adjustable to preset the actuation of said switch to a selected angular velocity of said magnetized rotor.

6. The induction switch of claim 4 characterized in that said actuator contacts, said axis of rotation of said second rotor, and said axis of rotation of said lever are prepositioned relative to each other to preset the actuation of said switch to independently selected clockwise and counterclockwise angular velocities of said magnetized rotor.

References Cited UNITED STATES PATENTS 2,880,288 3/ 1959 Rosenberg 33568 3,021,402 2/1962 La Warre et a1. 200-61.46 3,091,680 5/1963 Adrig. 3,180,163 10/1963 Kripke et a1 ZOO-61.46

FOREIGN PATENTS 1,160,963 8/1958 France.

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDERHYE, Assistant Examiner US. Cl. X.R.