US1815989A - Automatic switch - Google Patents

Description

3 Sheets-Sheet l R. E, RUESS AUTOMATIC SWTCH Filed Aug. 20. 192

July 21s, 1931` VMM 3 Sheets-Sheet 2 R. E. RUESS AUTOMATIC SWITCH Filedgug. 2o, 192s Jly 2s, 1931.

July Z8, 1931. R E. RUESS gg AUTOMATIC SWITCH V u Filed Aug. 20, i928 .3 Sheets-Shee 5 MH HI Patented July 28, 1931 PATENT OFFICE ROBERT EMERY RUESS, OF PHILADELPHIA, PENNSYLVANIA AUTOMATIC SWITCH Application led August 20, 1928. Serial No. 300,656.

My invention relates to automatic switches of the centrifugal or governor type.

One of the principal objectsof my 1nvention is the provision of a switch of this 5 character which is adapted to govern the aciion of electric motors and generators and other electrically-operated or electrlcallycontrollable devices having rotatable parts.

The switch is so designed and constructed that it may be employed 'either as an independent governing unit rotatably connected with the device to be controlled, or as a structural element of a motor or generator.

Another object of the invention 1s the provision of an improved automatic switch of the governor type which is capable of controlling an electric circuit, or a plurality of circuits, at any predetermined points of rotative speed of the member or device to be controlled.

Another object is to provide an automatlc switch of this character in which the action of circuit opening and closing is critical, sharp, positive and arcless, and in which the operating parts of the switch are free of torque strains;

A further object is to produce an improved centrifugal type switch provided with adjustable resistances by means of which the desired sharpness of action of the circuit opening and closing means may be obtained, to move the movable switch element quickly and positively to its operative positions and effectively maintain it in either of such positions; and by which the opening and closing action may be effected at any desired and predetermined rates of rotative speed of the device or apparatus to be governed.

The device by which I accomplish these and other beneficial results is capable of varied uses. As an independent unit, it is adapted to be connected to the starting motor of an internal combustion engine, to cut out the starting motor when the engine is in 0peration and to cut in the starting motor whenever the engine falls below a predetermined speed. Or the switch may be con"- nected to or associated with suitable means foroperating a clutch device associated with an internal combustion engine,'so that the circuit opening or closing action of the switch will eiiect the engagement of the clutch when the engine has attained a predetermined spee Also, as a structural element of, or structurally included in or combined with, a motor or generator assembly, my switch device is capable of accomplishing several important and useful results. For example, when so positioned or arranged, it is adapted to maintain the synchronization of a synchronous motor. Or, in the case of a generator, the switch is capable of controlling the voltage, the action of the automatic switch cutting the load on the generator in or out for any selected voltage.

My invention thus constitutes a centrifugal control device capable of use in various rela-- tions and for the accomplishment of a variety of specilically diierent functions and results. The invention is illustrated both as a separate and independent unit and as a structural part of a motor or generator. In the drawings- Figure l is a central longitudinal sectional View of the preferred form of my device, constructed as an. independent entity capable of more or less general application.

Figure 2 is a transverse sectional view on line 2-2 of Fig. 1, looking in the direction of the arrows,

Figure 3 is an enlarged sectional View of the slidable contact ring similar to the view illustrated in Fig. 1,

Figure 4 is an enlarged detail sectional view taken on line 4 4 of Fig. 1,

Figure 5 is a side elevational view, partly in section, showing the automatic switch il lustrated in Fig. l enclosed in and forming a structural element of the .rotor of a motor or generator, and

Figure 6 is a view similar to Fig. 3, showing a modified form oi construction of fixed and slidable contact rings.

As will be apparent from the drawings,- my invention comprises, generally speaking, a .rotatably mounted support, preferably in the form of a cage or casing and designed to be rotated, directly or indirectly, by the device with. which it may be associated and shown as a complete and independent structural unit, designed to control various rotative devices and to be rotated by the apparatus or device to be governed.

My invention does not require that the switch device be rotated in a magnetic field, but certain beneficial results accrue from 4such manner of use, and I prefer to have the switch casing rotatably positioned in a stationary magnetic field, as shown, for example, in Fig. 1.

In the construction illustrated in Figs. 1 to 4, inclusive, the parts of my centrifugal switch are contained in a switch casing A, rotatably suspended in suitable bearings in a frame B between fixed poles 51, 52, projecting inwardly of the frame. Ihe magnetic field within which the switch casing rotates is produced by coils 53, 54, energized from any suitable external source in a wellknown manner. The mounting of the switch easing in a magnetic field in this way, although not strictly necessary, is useful in that it serves as a magnetic blowout to prevent arcing of the switch contacts.

The easing A is preferably formed of a cylinder 1 closed at its ends by end plates 2 and 3, detaehably secured by screws 4 or other suitable means. The switch casing may be secured to and supported by a rotatable shaft or other rotatable part or device which is to be governed. Preferably the casing is rotatably mounted upon a supporting frame or within a suitable housing. When supported on a frame or housing, as shown in the drawings, a journal shaft is .rigidly secured at each end of the casing, either directly to the respective end plates 2 and 3, or, as is preferred, to mounting plates which mag be screwed or otherwise removably attac ed to the end plates. In the construction illustrated, involving the use of a plurality of fixed contacts and the control of a plurality of electric circuits, each of the mounting plates also carries two collector rings for establishing electrical connection between the contact wires which lead from the switch casing and suitable exterior circuit wires. Shaft 57 for example, has xed upon it a collar which is screwed or otherwise secured to mounting plate 55 and carries collector rings 59 and 60. This shaft is journaled in ball bearings 64 positioned in an aperture in frame B and retained in position by being confined between an annular shoulder 65 on the shaft and a nut 66 on the screw-threaded end of the shaft. Shaft 57 and mounting plate 55 have a screwthreaded axial bore to receive the adjusting screw 31 of the switch, which screw is provided with a lock nut 67 for retaining it 1n adjusted position.

Shaft 58, at the opposite end of the device, has its collar 71 rigidly secured to plate 56, and is supported in frame B by means of ball bearings in a bearing housing 50. This shaft carries collector rings 61 and 62 and a gear 68, or other suitable means, by which the switch casing connected to it may be rotated.

Any ordinary or convenient means associated with the collector rings for establishing electrical connection between the interior and exterior circuit wires may be employed. The means -illustrated comprises brushes 68 supported upon brush studs 69 and provided with the usual brush leads 72.

An axial bore through the plate 56 and shaft 58 slidably receives and guides the end of the axial rod 24 which projects out of the switch casing A.

W hen my switch device is incorporated in a direct current generator or direct current motor rotor, one of the mounting plates 55, 5G, has a eommutator assembled on its journal shaft, while the mounting plate upon the opposite end carries four collecting rings, for use with the two-circuit switch illustrated.

In the specific embodiment of the invention illustrated, the interior wall of the cylinder 1 of the casing is bored or recessed to receive a fixed contact ring support 5 and a slidable contact ring 18. The fixed contact support is of insulating material and has in its exposed face one or more fixed contacts, each comprising a plurality of metallic ring segments arranged in annular relation and spaced from each other at their ends by insulating ribs 6. Ordinarily, one such annular set of contact segments will be suflicent, and this fixed contact may be located in the position of either of thc fixed contacts shown in Fig. 1. Adjacent segments of cach annular set are connected tc different circuit wires to form one or more circuits normally interrupted by ribs 6. In the specific embodiment of the invention shown in Fig. 1 two annular sets of ring segments are provided, each being composed of two segments. The segments 7 and 8 of one set are connected to circuit wires 9 and 10, respectively, which extend into the easing through suitably insulated apertures 11 in end plate 2 and conduits 12 in cylinder 1. Segments 18 and 14, of the other annular set. are similarly connected to wires 15 and 1G of the sam-e or a different circuit, these wires preferably extending into the casing through insulated apertures 17 in end plate 3. Where it is desired to control a greater number of circuits, a greater number of ring segments may be employed, the segments being connected by suitable wiring in spaced pairs in any predetermined arrangement in the same circuit or in a plurality of different circuits.

Then the switch device is arranged for rotation in a magnetic field, as illustrated, the wall of cylinder 1 of casing A should be of iron, am the governor weights and other movable parts of non-magnetic material.

Control of t-he circuit or circuits in which the rin" segments or fixed contacts are incorporated is ei'lected by the axial movement of the slidable Contact ring 18, und-er the inlinence ofthe centrifugal movement of the governor weights 19. The movement of contact ring 18 is limited in one direction by the annular shoulder 28 formed in the wall of cylinder 1, and in the other direction by an annular stop rib 29 on end plate 3. Ring 18 is set in a metal channel casing 20 and insulated therefrom by a ring 21 of channel form of any suitable insulatingmaterial. Within the ring 18, at spaced intervals around the ring and contacting therewith, spring-pressed contact buttons 22 are set. The edges of casing 20 being beveled, and ring 21 being of insulating material, the contact between the slidablc ring 18 and the contact segments of the xed support 5 is effected by the projecting buttons 22, the springs bearing upon these buttons insuring proper contact at all times.

The slidable contact ring 18 and the other movable parts of the switch are supported upon a sleeve 23, slidable upon an axial rod 24, which is in turn slidably supported at one end in an aperture 25 in end plate 3 and at its opposite end is -provided with a head 26 slidably supported by and adjustable Within a :guide cylinder 27 which projects inwardly from end plate 2. The gui-de cylinder 27 also receives one end of the slidable sleeve 23 and forms an enclosing casing for a coil spring 30 confined between the end of sleeve 23 and the head 26 of axial rod 24. The action of the spring 30 tends to force the sleeve toward the right and to maintain it in that position in opposition to the force exerted by the c entrifugal action of the governor Weights 19 tending to pull the sleeve to the left when the casing is rotated. The tension of spring 30, and consequently the resistance to be overcome by the centrifugal action in the operation of the switch, may be regulated by means of an adjusting screw 31, which projects through a screw-threaded aperture in end plate 2 and bears upon head 26 of the axial rod 24.

The governor Weights 19, by which the movement of the slidable Contact ring is effected, are supported Within the casing A upon toggle arms pivotally secured at one end to the casing and at the other end to the slidable sleeve 23. In the specific embodiment of the invention illustrated six governor weights are shown, but a larger or smaller number may be employed. Each of the weights is hung on a toggle arm composed of llnks 32 and 34, each pivoted to the weight. The link 32, at its other end, is pivotally attached to the end late 2 ofthe casing, as at 33, and link 34 1s similarly connected to sleeve 23. The link 41 which pivotall connects sleeve 23 and slidable contact rlng 18 is resiliently extensible, and is preferably formed of telescopic sections. One of the sections, pivoted to sleeve 23, is in the form ot' a piston rod 35 screwed into bore 37 of a piston 38 and held therein by a lock-nut 36. The piston 38 is slidably positioned Within a piston chamber' 39 in a tubular casing'40. 'lhe casing 40 is pivotally connected to an ear 42 provided for this purpose on easing 20 of contact ring 18. A coil spring 43 within the casing bears against piston 38 and tends to maintain the telescopic link in extended condition and provide av resilient resistance to the shortening of the link by the movement ot' the piston 38 inwardly of casing 40. The degree of resistance offered to such movement may be varied by adjustment of piston 38 and nut 36 on rod 35.

In the operation of the switch mechanism the movement of the slidable contact 18 controls the circuits through the contact rings 7 8 and 13-14, this circuit control being effected by the centrifugal motion of governor weights 19. When the rotatable device to be governed and the switch casing A connected to it are at rest or rotating at lov7 speed, the governor weights and other movable parts, under the combined infiuence of springs 30 and 43, are forced to occupy the positions indicated in dotted lines in Fig. 1, and positively held in the dottedline position shown in Fig. 1, due to the extension of the spring links by springs 43. In this position contact ring 18 bridges the gap created by ribs 6 between ring segments 7 and 8 and may thus close an electric circuit, for example, through the starting motor of an automobile engine and, by appropriate and Well-unders" ood use of a relay, may hold open another circuit, for example, a circuit including an alarm signal.

Upon an increase in the speed of rotation of casing A, the governor weights 19 move outwardly in opposition tothe resistance presented by springs 30 and 43. As the speed increases, the centrifugal motion of the governor weights continues and links 34 pull the sleeve 23 along the axial rod 24 and straighten and shorten the telescopic links 41. As the points of attachment of these links to sleeve 23 pass the center line, the expansion of springs 43 extends the -links 41 and provides a snap action for moving contact ring 18 to the position indicated in full lines in Fig. 1. The parts are so arranged and adjusted'that links 41 and contact ring 18 Will be brought to this full line position when the rotation of the casing has attained a predetermined speed. The contact ring 18 is positively maintained in this position by springs 43, so that a proper and continuing contact is assured. In this position of contact ring 18 it closes the circuit through the segments 13 and 14 of theiother tixed contact ring, to operate an alarm signal or .any other desired electrical device. For example, the circuit thus closed, or a branch circuit, may contain an electrically operated device for cutting off the ignition of an automobile when the automobile engine has attained a predetermined speed.

When the rotative speed of the casing decreases, sleeve 23 must carry links 4l hack past the center line against the resistance ot' springs 43, in order to return contact ring 18 to its dotted line or rest position.

By the use of a plurality of fixed contacts and circuits connected therewith, my switch device can thus be made to operate the respective circuits at any different predetermined rates of speed, there being no iixed ratio for the operative speeds. For example,-it can open one circuit and close another at 5() R. P. M., and reverse the opening and closing of these circuits at R. P. M. Or the parts of the device can be adjusted. by meansl ot adjusting screw 31 and nut 86. to open and close, or close and open any of the circuits at any predetermined rates of speed. For example, instead of 50-60 R. l. M.. the operative speeds selected might be 7 5-100, 1GO-150, 1200-1400, etc.

lf it is desired to control a greater number of circuits, this result can be accomplished by an arrangement ot' contacts such as that shown in Fig. 6, wherein the slidable contact ring 18a is made ot' spaced segments insulated from each other, each segment having a pair ot contact buttons 22a arranged to make contact with and bridge the gap between a pair of fixed contact segments 107, 108 in the support 5a. The ixed contact segments are spaced radially and arranged in axially spaced pairs. The segments of the fixed and slidable contacts may be made as short as desired, and as many of these sets of contact segments may be used in forming the contact rings as may be found necessary or convenient, the number being determined largely by the number of circuits to be controlled.

It will be observed that the rates of speed at which the movement of the sli-table contact 18 engages or disengages the fixed contacts, to open or close one or more circuits through the latter, arf' determined and regulated by the adjustment of the tension of springs 30 and 43.

The switch casing, governor weights, contacts and all other parts of my switch device are in fixed relation to each other, as regards rotary motion. The cylinder 27 and axial rod 24 are subjected to no torque strains, but

serveI merely as guides for axial movement of the parts associated with them. rl'he springloaded contact arms formed by telescopic links 4l and the governor arms, composed of links 82 and 34, are definitely balanced by the spring-adjusting means heretofore described. 'lhe springs 3U and 43, when properly adjusted for operation at the predetermined rates ot speed, cooperate with the movement ot the governor weights 19 to produce a sharp and positive opening and closing action ot' the switch by the movable Contact 18.

As indicated above, the switch construction Which constitutes my invention may be used as an independent unit rotatably supported in any suitable manner, either directly upon the shaft or other rotatable device or apparatus to be governed, or upon a separate rotatable element connected thereto, or may be journaled in a frame or housing and rotatlively connected to the device to be governe( When the switch casing and enclosed operating parts of the switch, constructed as illustrated in Fig. 1, are incorporated in the rotor ot a motor or generator. as shown in Fig. 5, the switch casing A may be secured to journal shafts 57, 58, and rotatably mounted in the end bells 75, 7 6 of the motor or generator, in the same general manner as the mounting is etlected in the arrangement shown in Fig. 1. The cast iron yoke 77 of the motor or generator carries laminated poles 78, 79, forming the polar structure of the stator. The rotor comprises the rotatably mounted switch casing A, with suitable polar projections 80, 81, the windings 82, 83 of which are connected to collector rings or commutator 84, 85. The wires from the segments of the fixed contact ring or rings Within the switch casing may be connected to collector rings 86, 87, the number of which will depend upon the nurnber of contact rings provided in the switch construction and the number of circuits to be controlled.

Thus incorporated in the rotor, the switch casing rotates as a part of the rotor and serves to control the motor or generator, as the case may be, in the manner and with the results mentioned above.

I claim:

1. An automatic switch device comprising a rotatable casing, an axially disposed guide cylinder in said casing, an axial guide rod slidably mounted in said casing and having a head slidably engaging within said cylinder, a sleeve slidable on said rod and extending into said cylinder, a coil spring in said cylinder between said head and said sleeve, an adjusting screw extending through said casing and engaging said head to vary the tension of said spring against said sleeve, toggle arms pivotally connected to said casing and to said sleeve, centrifugal governor mem` bers supported on said toggle arms, a link formed of telescopic sections pivotally connecting said sleeve and said slidable contact, a coil spring interposed between said sections and tending to hold said link in extended condition, and means for adjusting the ten- Sion of said last-mentioned spring.

2. An automatic switch devlce comprising a rotatable casing, a guide cylinder in said casing, a guide rod in said casing, a sleeve slidable on said rod and extending into said cylinder, a spring in said cylinder bearing upon said sleeve, means for varying the tension of said spring, a fixed contact and a movable contact, centrifugal governormembers Within said casing, toggle arms supporting said governor members, each toggle arm being pivotally connected to said casing and to said sleeve, and pivotal connections between said sleeve and said movable contact.

3. An automatic switch device comprising a rotatable casing, a guide rod in said casing, a sleeve slidable on said rod, a fixed contact and a movable contact, centrifugal governor members within said casing, toggle arms supporting said governor members and pivotally connected to said casing and to said sleeve, and a resilient connection between said sleeve and said movable contact, said resilient connection comprising telescopic members, an interposed coil spring, and means for adjusting the operative relation of the telescopic members and interposed spring.

4. An automatic switch device comprising spaced plates connected and adapted to be rotated together, an axially disposed guide cylinder on one of said plates, a lixed electric contact and a slidable contact carried by and insulated from the other plate, an axial guide rod slidably mounted in said other plate and slidably engaging within said cylinder, a sleeve slidable on said rod and extending into said cylinder, a spring in said cylinder bearing upon said sleeve, means for varying the tension of said spring, toggle arms pivotally connected to one of said plates and to said sleeve, centrifugal governor members supported on said toggle arms, and pivotal connections between said sleeve and said slidable contact.

5. An automatic switch device comprising a. rotatable casing, a guide in said casing, a slidable member carried by said guide, centrifugal governor means within the 'casing pivotally connected to said casing and said slidable member, a fixed contact in the wall of said casing, and a slidable contact pivotally connected to said slidable member.

6. An automatic switch device comprising a rotatable casing, a guide in said casing, a slidable member carried by said guide, governor means comprising centrifugal governor members within said casing, toggle arms supporting said governor members and pivotally 5 connected to said ,casing and said slidable member, a fixed contact inthe side wall of said casing, a slidable contact sleeve ad. 'ted to engage said fixed contact and a 'ent pivotal connection between said slidable contact and said slidable member.

7. An automatic switch device comprising a rotatable casing, an axial guide rod in said casing, a member slidable on said rod, centrifugal governor members in said casing, toggle means supporting said governor members and pivotally connected to said casing and said slidable member, a fixed contact, a slidable contact, and resilient means pivotally connected to said slidable member and said slidable contact.

8. An automatic switch device comprising a rotatable casing, a guide in said casing, a. slidable member carried by said guide, a centrifugal governor within said casing pivotally connected to said slidable member, a ixed Contact in the side wall of the casing, a slidable contact sleeve adapted to engage said fixed contact, and a pivotal connection between said contact sleeve and said slidable member. .Y

9. An automatic switch device comprising a rotatable casing having an annular recess in the inner surface of its side wall, a guide in said casing, a slidable member carried by said guide, centrifugal governor means within said casing pivotally connected to said casing and said slidable member, longitudinally spaced fixed contacts in said recess, a contact sleeve slidable in said recess, and a resilient pivotal connection between said Contact sleeve and said slidable member.

l0. An automatic switch device comprising a rotatable casing, a guide in said casing, a. slidable member carried by said guide, governor means comprising centrifugal governor members within said casing, toggle arms supporting said governor members and pivotally connected to said casing and said slidable member, a fixed contact in the side wall of said casing, a slidable contact sleeve adapted to engage said fixed contact, a resilient pivotal connection between said slidable contact and said slidable member, a spring bearing upon said slidable member and opposingthecentrifugal motion of said governor means, and means for adjusting the tension of said s rin p g ROBERT EMERY RUESS.

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