US2086754A - Control device - Google Patents

Description

July 13, 1937.'.V c. J. WERNER ET A1. 2,086,754

' CONTROL DEVICE Filed July 18, 1934 5l za 5 5l 23 24 l d 24 j; l 14 -52 30 i 30 5g w T z8 i l od M o Q 35 Q/as CALVIN J WERNER AN CARL H. KINDL.

ATTO R N EYS Patented July 13, 1937 PATENT @FFICE CUNTRL DEVIGE Calvin J. Werner and (Carl El. Kindl, Dayton,

Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application Jilliy i8, 19%, 'Serial No. 735,903

8 Claims.

This invention relates to control devices, and more particularly to one operating responsive to the speed of a movable member, such as are used for controlling an electric motor.

An object ofthe present invention is to pro=l vide 'a control device that is responsive to the speed of a `movable member and that minimizes mechanical operating noise.

In the disclosed embodiment of this invention, the control device incorporates a combination op.: erable cooperatively with' a movable member or shaft and comprising a magnet, a movable arma ture having anormal position with respect to the magnet, a speed responsive means eilecting a change of the air gap between armature and magnet in response to a change in speed oi the rotatable member or shaft, which change in air gap eects m0vement`of the armature with res spect to the magnet, and control means actun ated by the armature.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompany-1 ing drawing, wherein a preferred embodiment ci one form of the present invention is clearly7 shown.

In the drawing:

Fig. l is a fragmentary sectional view oi an electric motor equipped with the present invena tion. In this view the automatic control device is shown in normal position.

Fig. 2 is a view similar to Fig. l showing the control device in operated position.

Fig. 3 is a fragmentary detail view` taken in a direction oi the arrow of Fig. i.

Fig. 4 is a view similar to Fig. 3, taken substan tially in a direction of the arrow ci Fig. 2.,

Referring to the drawing, 'the motor is shown comprising a frame y 20, having held windings 2l. An end cover 22 is attached to the trarne to in any suitable manner, said end cover providing a bearing 23 winch supports one end or the y armature or rotor shaft 24.

Alug 25 is provided on the inner surface oi the end cover 22, this lug forming a mounting block for the magnet 26 of the control device. niother lug 21 on the cover 22 comprises a mounting block for stops or terminals of the control device.

Referring to Figs. 3 and 4 in particular, a sta tionary contact element 28 is shown mounted on the lug 21, insulated therefrom by the member 29. Another stationary contact 30 is insulatingly carried by said lug 2i. Contacts 2% and 3@ are in alignment and properly spaced so as to have the movable arm 3| carrying contacts t? and.

(Gi. mil- 530i on opposite sides thereof positioned therebe" tween. The arm il which carries contacts 32 and 33 is secured to a resilient blade spring 34, one end of which is shown riveted to the end 35 of the magnet 2B. The resilient blade spring 34 has a member 3o attached thereto, which member is oi' magnetic material and; forms the movable armature of the control device. The other end or pole of the magnet 26 is designated by the numeral 4B. "in the present instance the magnet 2t is shown as a permanent magnet, but it may clearly be understood that this could be an electromagnet having a winding adapted to be brought into the circuit and energized when the circuit to the motor is closed for running purposes.

lt will be seen that the air gap between the armature 36 and the opposite pole 40,0f the magnet is so great that the magnetic reluctance will render the magnetic force ineffective to move the armature 36 toward the pole end 40 and consequently the blade spring 34 will normally bias to cause contact 32 on arm 3l to engage the stationary contact 29.

order to move the contact 32 out of engagement with contact 28 it is necessary to introduce a magnetizable element between the armature B6 and the pole end 40 of the magnet so as to reduce the magnetic reluctance and render efiective the magnetic force to attract the armature 33. ln the present instance applicants have pron vided a centrifugal governor on the shaft it which governor includes a weight member 5l normally biased. into the position as shown :in Fig. l by a spring 52. At a predetermined R. P. ivi.' ot the shaft 24 a speed responsive Weight 5i will be moved into the position as shown in Fig. 2. in its normal position this speed responsive element or weight 5i is suihcientiy out of the magnetic iield of the magnet it so as not to cause movement of the armature 3E. This is clearly shown in Figs. i and 3. However, when the magnetizable weight or speed responsive element 5I of the governor' 5U is moved into the position as shown in Figs. 2 and 4, said element enters into the magnetic field oi. the magnet 2S, reducing the magnetic reluctance by closing the air gap ben tween the armature 3G and the pole end #ill of the magnet so that the magnetic force. may attract the armature it by netting spring blade 3&3, moving it into the position as shown in Fig. in which position contact 32 is out of engage-1 ment with contact E8, and contact 33 is in engagement with the stationary Contact Sil.

in the present drawing, the control device when in normal position permits certain contacts to engage while, when moved into the active or operated position, in response to speed in this instance, these certain contact engagements are broken and others are made. It may clearly' come within the realm of the present invention Where, instead of breaking one contact and clos7 ing another one, the movable contact member is merely moved from normal stop engaging position into the active contact making position, or in another instance at a predetermined a circuit may be broken by moving the movabie contact out oi engagement with a live terminal into a position in rwhich merely engages stop. are modifications which arenierely obvious and entail no invention.

From the aioregoing it may ciearly be seen thatl applicants have provided a control device adapted to be actuated in Vmiese to the movement of a respon. without noisy operation, for no c. tacts are made to move the controi this being done magnetically. The only actual corr tact made by moving parte is that made by the moving control element, this instance movable contact engaging either terminais or stops.

From the foregoing description ci tl'ie construction and mode of operation ci this control device, it will be clearly understood that the device chiefly includes a rotatable member 24;

vcontrol means 28, 39, 3|, s2 and 33; a magnet 2li and an armature 35, at least one of which (armature 35 as disclosed) is movable in rcsponse to magnetic force between them to actuate the control means 2i, 3G, 3|, 32 and 33; and means 5I and 52 comprehending a spring 52 having one end connected to the rotatable member 24 for controlling the reluctance of the magnetic path between the armature 36 and magnet 26 in rezsponse to the speed of the rotatable member While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

l. A control device comprising, in combination, a rotating member; a magnet; a hinged, polar extension for said magnet; speed responsive means driven by the rotatable member and movable between the polar extension and the other pole of the magnet to reduce the magnetic reluctance therebetween for eiecting movement of the polar extension; and a control device actuated by said polar extension.

2. A control device comprising, in combination, amagnet; a blade spring attached at one end to one of the ends of the magnet; a contact cargried by said blade spring; a stationary contact adapted to be engaged by said contact; a magnetizable member carried by the blade spring, said member 'forming an extension for the one pole of the magnet; and means adapted to be moved into the air gap between the magnetizable member and the opposite pole of the magnet, for reducing the magnetic reluctance therebetween and eiecting movement of the contact carrying blade spring relatively to the stationary contact.

3. A control device comprising, in combination, a magnet; a blade spring attached at 4one end to one of the ends of the magnet; a contact carried by said blade spring; a stationary contact adapted to be engaged by said contact; a magnetizable member carried by the blade spring. said member forming an extension for the one pole of the magnet; and a centrifugal governor having a magnetizable member adapted, in response to centrifugal force, to be moved into the cir gap between the magnetizable member and the opposite pole of the magnet, for reducing the magnetic reluctance therebetween and effecting movement oi' the Contact carrying blade spring relatively to the stationary Contact.

i control device comprising, in combination,

` iilagnet; a ilexible, nom-magnetic member attween. the magnetiaable element on the iiexible member and the opposite pole of the magnet for reducing the magnetic reluctance therebetween and rendering the magnetic force eiiective to actuate the movable part of the control device.

5. il. controi device responsive to speed, compricing, in combination, a rotatable member; a magnet; a movable amature having a normal position with respect to the magnet; means comprehending a resilient member effecting control oi the air gap between the armature and magnet below a predetermined speed of the rotatable member and in response to changes oi speed of the rotatable member; and control means actuated in response to the change in air gap corresponding to a speed above said predetermined speed.

6. A control device responsive to rotary speed comprising, in combination, a rotatable member; control means; a magnet and an armature, at least one of which is movable in response to the magnetic force between them to actuate the control means; and means comprehending a spring having one end connected to the rotatable member for controlling the reluctance of the magnetic path between the armature and magnet in response to the speed of the rotatable member.

7. A control device for a motor having a shaft comprising, in combination, a stationary magnet; a resiliently mounted armature having a normal position with respect to the magnet; a magnetic member pivotally mounted on the shaft and normally biased away from the armature and-magnet, said magnetic member being movable toward the 'magnet and armature under the iniluence of centrifugal force when the shaft rotates to effectively reduce the reluctance of the magnetic path between the armature and magnet and effect movement of the armature.

8. A control device for a motor having a frame and a shaft comprising, in combination, a-resiliently biased member secured to the frame, a second member pivotally secured to the shaft and rotatable therewith, and magnetic means, said second member being movable responsive to cen'- trifugal force to effectmovement of the resiliently biased member with respect to the magnetic means.

CALVIN J. WERNER. CARL H. KINDL -rmined speed, to move into the air gap ben'

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