US2158164A - Contact device - Google Patents

Description

Ma 16, 1939. R. VAN WYNEN 2,158,164

CONTACT DEVICE Filed Oct. 21, 1937 FIGJ.

'INVENTOR RUSSELL V/W kW/VE/V BY flu M ATTORNEYS Patented May 16, 1939 UNITED STATES CONTACT DEVICE Russell Van Wynen, Westmount, Quebec, Canada, assignor to Schick Industries Limited, Nassau, Bahama Islands, a corporation of Bahama Islands Application October 21, 1937, Serial No. 170,134 I 9 Claims.

This invention relates to contact devices and particularly to contact devices for use under circumstances which require precise adjustment of the timing of a circuit in relation to a rotating body such as the armature of an impulse motor.

It is among the objects of the invention to provide means for mounting one of the contact members of a contact. device in a manner enabling variation of the position of impact of the contact points carried by the contact device whereby the timing of the electrical circuit controlled thereby may be varied as desired. This results in enabling accurate factory adjustment and affords simple and easily adjustable means for correcting for wear of the operating parts.

Another object of the invention is to provide in a contact device of the type wherein one of the contact members is continuously operated and the other contact member is relatively stationary, mechanism by which such a contact device is made capable of long use without the excessive wear which frequently afl'ects devices of this type because of the impacts deliveredagainst the stationary contact.

26 Another object of the invention is to provide a contact device and mounting means for securing the same upon a support or base made of Bakelite or equivalent condensation product and which is capable of prolonged use without such loosening of. the mounting means as to impair the-correct operating relationship of the parts of the contact device.

Further and other objects of the present invention will be hereinafter set forth in the ac- 'companying specification and claims and demonstrated by the drawing which shows by way of illustration a preferred embodiment and the principle of my invention and what I now consider the best mode in which I have contemplated applying that principle. Other embodiments of the invention employing the same principle may be used and structural changes made as desired by those skilled in the art, within the spirit of the appended claims and without departing from the present invention.

In the drawing:

Fig; 1 is a plan of the contact device and its mounting.

Fig. 2 is a section on line 2-2 of Fig. 1 showing a section through the adjusting mechanism.

Fig. 3 is a view showing the upper portion of a contact member and a section through the cam or eccentric by which adjustment of position is 55 accomplished.

Fig. 4 is a section on line 4-4 of Fig. 1 showing the supporting stud for the contact member.

The contact device of the present invention has advantages for controlling circuits of impulse motors. and has particular utility with impulse 5 motors of. small sizes such as are used in shaving devices and in other hand tools employing portable motors. The efiiciency of operation of an impulse motor is in part dependent upon the proper timing of the circuit which energizes the 10 field 0011s. The energization of the field coils is usually accomplished. by a contact device adapted to make and break the circuit under control of the rotating armature. For this purpose the armature shaft is provided with a cam 15 mounted in definite angular relation to the armature to cause opening and closing of the circuit when the armature is in predetermined positions in respect to the pole pieces of the motor. The adjustment required for accomplishing this 20 can be made in the factory when the motor is assembled but unless correction is applied from time to time, the timing of the circuit may change owing to the wear resulting from extensive use. The device of the present invention fa- 25 cilitates adjustment and correction of the timing of the circuit and makes the adjusting operation simple enough to understand for individuals lacking the skill of a factory technician. In view of. its particular suitability for a me- 30 chanical shaver, I have chosen to explain my invention in conjunction with such a device. In Fig. 1 I have illustrated the upper portion of a hollow handle l0 which constitutes a container or casing for the motor. The contact device in-, 35 cludes a breaker arm ll pivotally mounted upon a post l2, and a contact member l3 which is supported at its lower end upon a collar of another post in the form of a shouldered screw Id. The mounting for contact member l3 provides 40 for slight motion upon impact from the breaker arm and angular adjustment about the axis of screw ll. Post I2 and screw H are mounted upon a base l5 which in the present embodiment of the invention consists of a block of Bakelite 5 or equivalent condensate material.

This base has a thick solid portion H5 at its upper end which carries a journal bushing I! for the pivot shaft l8 of a lever ill by which the movable cutting element 20 of the shaver is op- 5 erated. Depending from the upper portion l6 there are two thinner plate- like portions 22 and 23, between which the armature 24 of the motor is mounted. The front portion 22 carries a bearing 25 for shaft 26 of the armature and a similar bearing is mounted in rear portion 23. The base is secured to the field magnet by bolts 21 engaging the rear portion of the base and the poles of the magnet.

Preferably the base is made in one piece so that journal I! of pivot shaft 18 and the bearings for shaft 26 may be carefully positioned and the mounting of the respective shafts in parallel relationship assured. This is important because a cam (not shown), which actuates the lower end of lever Ill, is carried by armature shaft 25 and accurate mounting of the shaft it in respect to its driving member is desirable.

The center of shaft 26 is mid-way between a pair of field poles it, 29 of the magnet.

The end of the armature shaft which extends beyond the outer surface of the front plate-like portion 22 of the base has a cam 3% by which the breaker arm ii is operated. The breaker arm may be of any conventional type, the one illustrated consisting of a sheet metal arm provided with a journal for engaging post 112. The free end of the breaker arm carries a contact point 3i made of tungsten or of other suitable material. This contact point is adapted to close a circuit between the breaker arm ii and contact member it through a cooperating contact point 32 which is carried by the contact member.

On the breaker arm, intermediate post l2 and the contact point 3i, there is secured a rubbing block 33 having a bearing surface which cooperates with cam ill] and causes the intermittent rocking of the breaker arm. A spring 3% is provided for restoring the closed condition of the contacts following each opening operation by the cam. One end of spring 36 is secured to the breaker arm and the other end abuts a post which is mounted on base 115. The free end of the spring provides convenient means for attaching the conductor 86 which is connected with the coil of the field magnet.

The armature of the motor illustrated has two poles ill and 38.

In the operation of the device, cam Sit on the armature shaft causes the breaker arm to be raised and contacts iii and 32 separated twice for each revolution of the armature. When a high part or" the cam passes rubbing block spring 35 causes the breaker arm to snap back and bring the contacts into contact with each other. In order to assure good electrical conduction between the contacts the low portions of cam ill] are preferably sufficiently low to clear the rubbing block and permit spring 34 to exert its entire resilient force towards maintaining the contacts closed. As a result of this, it is apparent that contact 32 receives the full force of the impact produced by the release of the spring pressed breaker arm when the high part of the cam passes the rubbing block. This is a desirable result because it tends to prevent filming between the contacting surfaces of the contacts and discourages the forming of oxides whose presence would otherwise impair electrical conductivity between the contacts. On the other hand, the repeated and numerous impacts upon contact 32 might cause loosening of the mounting by which the contact is held in place, with the result that the timing of the opening and closing of the circuit would be upset unless provision were made to avoid this result. As explained hereinafter, provision is made for absorbing without excessive shock the impact of the actuated contact.

In contact devices, much of the wear is likely to occur at the contact points and between the rubbing blockand actuating cam. Wear at either of these places will result in upsetting the timing of the circuit by changing the moments of making and breaking of the circuit at the contacts in relation to the angular positions of the armature, so that following prolonged use, the motor will not operate as efficiently as it did when it left the factory in its proper adjustment. Loss of material on surfaces of the contact points results in moving the line of contact toward the right (Fig. 1), with the result that for an armature rotating in a clockwise direction the contacts will be opened sooner. and closed later as the wear increases. Any wear of the sliding surfaces of the rubbing block and the actuating cam has the effect of causing the contacts to open later and to close sooner as the wear increases. These are of the sort of changed conditions which bring mounted upon a collar 39 of shoulder screw Fig. 4. The upper end of contact member i3 is provided with a hole iii (Figs. 2 and 3), in which there is disposed a cam 3i in'the form of an eccentric mounted upon a pin 12 whichextends in and is made fast to the base i5 upon which the contact device is mounted The top portion of the cam is provided with a knob it having a slot 66 therein by which the cam may be readily rotated to any desired position about the axis of the pin. Rotation of the cam upon pin t2 varies the angular position of the-contact member it about its supporting post it and by rotating the earn it is possible to change the normal position of impact of contact 32 and thereby change the moments of opening and closing of the circuit.

Under some circumstances the edges 15 and MB of hole Mi may be so spaced as to always engage the periphery of cam ii so that the cam would rigidly maintatin the contact member in its set position at all times. However, the effect of the repeated impacts upon a fixed contact tends to loosen the mounting holding the contact in place, with the result that any loosening that may de velop could cause disarrangement of the proper timing of the circuit and factory attention would be necessary to resecure the .mountings and restore correct timing. 1 have therefore provided means for resiliently absorbing the energy developed when the breaker arm is released and the contacts engage, and in order to accomplish this I have provided a spring 48 (Figs. 1 and 2).

This spring may be secured to or turned up at right angles from a bracket 49, which is fastened to contact member l3 by such means as rivets 50, M; or may be fastened by any other equivalent means, such as by welding. The free end or spring 48 rests against knob 43 and resiliently maintains contact member l3 against cam 4|. The position thus maintained is the position in which contact 32 receives the impact from the contact on the breaker arm. In this position edge 46 of hole is spaced from cam 4| (Fig. 3) so as to assure that the effect of the impact will be resiliently absorbed by the spring. Edge 45 of hole all is held against the cam as though it were an outside edge of the contact member.

As explained hereinabove, the position of impact of contact 32 may be varied by changing the angular position of cam 4| upon its supporting pin 42. In order to maintain the cam in the position in which it is set, the upper end of spring 48 preferably is hooked so as to engage one or another of the longitudinal grooves 52 in the outer surface,of knob 43. The spring thereby forms an abutment substantially tangential to and against any rotary displacement of the knob and associated cam.

In addition to thesefunctions, spring 48 acts to maintain the cam and knob upon the pivot post with the cam opposite an edge of the contact member. To attain this end a flange or shoulder 53 is provided upon the cam "and the inner side of this flange is held in engagement I with the outer side of contact member [3 by the edge of spring 48 which is located adjacent the outer side 54 of the flange. To remove the cam it is necessary only to flex spring 48 sufficiently to clear the periphery of flange 53 and then lift the cam from its supporting pin 42.

The flanges of rivets 50 and Si, which secure the spring to the contact member l3, serve to maintain the contact member raised from the base I5 and also afford restricted bearing surfaces. A spring washer 56 (Fig. 4)- engages rivet 5| and maintains thecontact member in position with the flange of the rivet bearing against the base upon which the contact member is mounted.

The contact member itself consists of a metallic plate having an end portion 51 turned-up at right angles to the plate and bent back upon itself where it is welded or otherwise secured to the plate, as at 58. The turned-up portion 51 serves as a support for the contact point 32, but any other suitable form of" support may be provided.

When the contacts are closed the circuit is completed through conductor 36, spring '34,

breaker arm H, contacts 3!, 32, contact member I3, a depending terminal 59 and conductor 60.

What is claimed is:

1. In combination, a contact device comprising a pivotallymounted breaker arm carrying a contact point, a contact member positioned for receiving impacts from said breaker arm, means supporting said contact, member for pivotal movement, a contfi'at point carried by said contact member and adapted to be intermittently engaged by the contact point on said breaker arm for controlling a circuit, means for actuating said breaker arm, means resiliently supporting said contact member against the force of impact imparted by the breaker arm at each closing of the circuit, said means including a spring initially stressed and exerting pressure upon the pivoted contact member against the direction .of closing movement of the contact point carried by the breaker arm while enabling pivotal movement of said contact member as the energy of impact is absorbed by said spring.

2. In combination, a contact device comprising a breaker arm pivotally mounted for actuation, a contact carried by said breaker arm, an

against said cam whereby shock of impact at the closing of the contacts is materially dissipated.

3. In combination, a contact device comprising a breaker arm pivotally mounted for actuation, a contact carried by said breaker arm, an adjustably positionable contact member, a contact carried by said contact member and arranged for cooperation with said first named contact, a base for supporting said breaker arm and contact member, a post for pivotally supporting said contact member, said supporting post being mounted 0n said base, a cam engaging said contact member and capable of chang ing the position of the contact member about its supporting post, means supporting said cam upon said base, and a spring carried by said contact member and having its free end in engagement with a portion extending from said cam, said spring serving to maintain the contact member against the cam.

4. In combination, a contact device comprising a breaker arm pivotally mounted for actuation, a contact carried by said breaker arm, an adjustably positionable contact member, a contact carried by said contact member and arranged for cooperation with said first named contact, a base for supporting said breaker arm and contact member, a supporting post for said contact member in engagement within a hole in the contact member, said supporting post being mounted on said base, a pin also mounted on said base and extending through another hole in said contact member, a cam rotatably mounted on said pin, a spring carried by said contact member and having its free end in engagement with a knob extending. from said cam, said spring serving to maintain the contact member resiliently against the cam to absorb energy of impact between the contact points, means on said knob for engaging said spring to prevent change in the setting of the cam, said means being grooves normal to the plane of rotation of the cam, and a shoulder carried by the cam, said shoulder being engaged by the spring to maintain the cam upon its supporting pin.

5. In combination, a contact device comprising a breaker arm pivotally mounted for actuation, a contact carried by said breaker arm, an adjustably positionable contact member, a contact car-' ried by said contact member and arrangedfor cooperation with said first named contact, a base for supporting said breaker arm and contact member, said base being of one-piece and consisting of a condensation product, a post for pivotally supporting said contact member, said supporting post being mounted on said base, a

cam engaging said contact member and capable" of changing the position of the contact member about its supporting post, means supporting said cam upon said base, and a spring carried by said contact member and having its free end in engagement with a portion extending from said cam, said springserving to'maintain the contact'member against the cam.

6. In combination, a contact device comprising a pivotally mounted breaker arm carrying a contact point, an adjustable contact member, a contact point carried by said adjustable contact member and adapted to cooperate with the contact point on said breaker arm for controlling a circuit, means for actuating said breaker arm, means supporting said adjustable contact member and enabling variation of its position and the position of impact of the contact 1 tact member and adapted to cooperate with the contact point on said breaker arm for controlling a circuit, means for actuating said breaker arm, means supporting said adjustable contact member and enabling change in its position for receiving impacts from the breaker arm, said supporting means being capable of positive determination of selected impact positions of the adjustable contact member, and self-locking means cooperating with said supporting means for normally holding said supporting means and adjustable contact member in selected positions.

8. In combination, a contact device comprising a pivotallyrnounted breaker arm carrying a contact point, an adjustable contact member, a contact point carried by said adjustable contact member and adapted to cooperate with the contact point on said breaker arm for controlling so a circuit, a base supporting said adjustable eontact member, means for intermittently actuating said breaker arm for causing engagement of the contact points, means cooperating with said adjustable contact member for determining the position in which it is to receive impacts from the breaker arm, and a spring carried by said contact member and engaging said position-determining means, said spring serving to bias said contact member and position-determining means into engagement with each other while also cushioning said supporting base from the shock of impact between the contact points.

9. In combination, a contact device comprising a breaker arm pivotally mounted for actua tion, a contact point carried by said breaker arm, an adjustably positionable contact member, a contact point carried by said contact member for cooperation with said first named contact point, a base supporting'said adjustable eontact member, a rotatably settable cam cooperating with said adjustable contact member for determining the position in which the contact member is to receive impacts from said breaker arm, means for supporting said 'cam upon said base, a spring engaging said cam, said spring serving to bias the contact member against the cam, and mean: engaging said cam and spring whereby the cam is held on its supporting means by the spring.

Vim" 'i/VYWEN.

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