US2640124A - Combined starting and protective switch - Google Patents

Description

May 26, 1953 v. G. VAUGHAN ETAL COMBINED STARTING AND PROTECTIVE SWITCH Filed March 21, 1950 4 Sheets-Sheet 1 4\ EAR I S y H FM 1 mHwn A m w A M W HMM a. A mm {UM 0 A VRJ v. G. VAUGHAN ETAL COMBINED STARTING AND PROTECTIVE SWITCH Filed March 21, 1950 May 26, 1953 4 Sheets-Sheet 2 S TAR TING RUN/VINO INVENTORS. V/crm? G. VflUGH/JN, Roaeer G. MAW/V6), JAMES A. BflG/VAZL, 4 Atty May 26, 1953 v. G. VAUGHAN ETAL 2,540,124

COMBINED STARTING AND PROTECTIVE SWITCH Filed March 21, 1950 4 Sheets-Sheet s INVENTORS, V/CTOR G. VAUGHAN, ROBERT 6. MA W/VEY, JAMES A. BAG/VALL May 26, 1953 v. G. VAUGHAN ETAL 2,640,124

COMBINED STARTING AND PROTECTIVE SWITCH Filed March 21, 1950 4 Sheets-Sheet 4 a0 I START/N6 INVENTORS, V/c TOR G. VAUGHAN,

Rosew- MAW/WY, dmwas A. SAGA/ALL,

Patented May 26, 1953 COMBINED STARTING AND PROTECTIVE SWITCH Victor G. Vaughan and Robert G. Mawney, Attleboro, Mass, and James A. Bagnall, Dearborn, Mich., assignors to Metals & Controls Corporation, Attleboro, Mass., a corporation of Massachusetts Application March 21, 1950, Serial No. 150,832

23 Claims.

This invention relates to combined starting and protective switches for electric motors, and more particularly to switches of this class which are applicable to motors having a separate starting winding.

Among the several objects of the invention may be noted the provision of a combined starting and protective switch for a motor having starting and running windings, in which the motor protecting device is a replaceable self-contained unit functioning as a part of the starting switch mechanism; the provision of a switch of the class described so constructed that it is impossible to leave the running winding of the motor connected into the power circuit without first actuating the starting contacts; the provision of a switch of the class described in which the motor protecting device is of the manually reset type so arranged that manually resetting the device after trip-out also actuates means for starting the motor to which the switch is connected; the provision of a switch of the class described in which the motor protecting device is so arranged as to be readily demountable from the switch so as to enable the ready changing of the rating of the protecting device to adapt the switch as a whole to various sizes of motors; and the provision of a switch of the class described which has relatively few parts, is simple and economical to make, and which is substantially foolproof in both its switching and protective functions. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is illustrated one of the various possible embodiments of the invention:

Fig. 1 is a cross-sectional elevation showing the component parts of one embodiment of the switch in non-operative position;

Fig. 2 is a plan view of the top of the Fig. 1 embodiment, taken along the sight line 2--2;

Fig. 3 is a plan view of the body of the Fig. 1 embodiment, taken along sight line 3-3;

Fig. 4 is a plan view of the bottom of the body of the Fig. 1 embodiment, taken along sight line 4-4;

Fig. 5 is a plan view of the top of the bottom of the Fig. 1 embodiment, taken along sight line 55;

Fig. 6 is a cross-sectional elevation of the Fig. 1 embodiment, taken from the opposite side, in order to show certain other details of construction;

Fig. '7 is a View similar to the view of Fig. 6 but showing the component parts in an intermediate operating position;

Fig. 3 is a view similar to the View of Fig. 6 but showing the component parts in a further operative position;

Fig. 9 is a fragmentary view of a portion of the view of Fig. 8, showing certain parts being returned to the non-operative position of Fig. 1;

Fig. 10 is a perspective exploded view in order more clearly to illustrate the component parts of this embodiment;

Fig. 11 is a cross-sectional view of the protecting device which is to be incorporated into the Fig. 1 embodiment;

Fig. 12 is a plan view of the top of another bottom part for the Fig. 1 embodiment, to show a possible different arrangement of certain parts therein;

Fig. 13 is a schematic wiring diagram illustrating a circuit into which the device with the bottom of Fig. 5 may be connected; and

Fig. 14 is a schematic wiring diagram illustrating a circuit into which the device with the bottom of Fig. 12 may be connected.

Similar reference characters indicate corresponding parts throughout the several views of the, drawings.

. In order to reduce the cost of motors for certain applications, the centrifugal switch which is incorporated in certain motors and which .serves to start the motor automatically by first connecting and then disconnecting the starting winding of the motor is eliminated. This centrifugal switch is then replaced by a manually actuated starting switch, generally of a fairly simple and inexpensive construction. In addition to the above, there is a growing tendency to use some kind of protective device in connection with the motor so that the motor may be as small as practicable for a given horsepower rating without burning out on overload. Several switches have been made and sold on the market which combine in the single switch both these starting and protective functions. However. these switches are generally so constructed that the protective mechanism is built integrally into the switch and protects only a single size of motor, and it is not possible to adapt such a switch to motors of diiferent sizes, either larger or smaller, without a relatively expensive replaceoperation on the switch to change the protecting mechanisms. This generally increases the cost of the switches. Also, such switches are sometimes of such construction that it is possible to latch the switch contacts into position for onneeting the running winding of the motor to line without first connecting the starting winding of the motor to line.

It is the general. purpose of this invention,

VELilOlls sizes of motors, and in which it is to leave the main winding of the motor connected to the power circuit without also having connected the starting winding to the power circuit. Other advantages and purposes of the invention will be obvious or will be pointed out hereinafter.

Referring now to the drawings, and in particular to T 1i there-is shown one embodiment of invention. The switch base is indicated g three per *cttoro part :1. These component parts of the switch base are made from electrically insulating material, of which good examples are the molded plastics.

The center p rt is provided with a. square hole -ich extends partially through this center t, and which is continued by round hole 6 of educed dimensions as indicated. Hole 5 rees square push button and in the present nee, hole t? is made square in shape in order r ep push button i from turning. Button 1 ise made of insulating material. A spring the bottom of hole 6 to bias push button 1 .r as shown. Button 7 is provided with an inwarcry inclining cam surface 9 and a horizontally extending surface If the purpose of which will be described later.

part is also provided with hole H nds completely throughout center part as shown, and which is of such size as to receive A the casing of a protective thermotat .n licated generally by numeral l2. Hole II of two diameters so as to provide the ledge 56 as shown.

The top surface of center part 3 is inclined ownwardly to the right as shown, in order to leave appreciably more space between the under i? of top and surface 3 at its inner nd than is provided at the outer end of surace ..cp part i. of this embodiment fits snugly over the center part B and the two parts are held ogether by screws (not shown) in any well known ashion. Top part 2 is provided with two holes and 55 passing therethrough and adapted slidably to receive pus button '1 and the manual reset knob i6 of thermostat l2, respectively. Holes are axially aligned with holes 5 and i l, hole ii is made square to correspond to the shape of button i.

Lying: wit" *1 the space provided between top surface 23 of center part 3 and the underside i1 is slide member 18. Push button '1 through a square hole IS in slide bowed spring member lying ii of slide l8 and the inner end "a cc surfaces 9 the right. It will be noted that slide 18 is of lesser thickness than the height of the above mentioned space formed between surface I3 and underside ll, permitting the inner end 54 of slide 53 to move in an up and down direction and thus providing lost-motion. A bowed spring member 22 fastened to underside l1 bears against the top of slide [8 and biases it downwardly against surface 13.

Spring member 22 is fastened to underside H in the present instance by providing a slot 23 in the underside IT with an upstanding peg 24 being provided at the center of slot 23. Spring member 22 is made of flat spring steel, for example, and is provided with tongues 25 and 26 at its center as shown to define hole 21. When hole 21 is forced over peg 24, the ends of the tongues 25 and 26 bend upwardly and engage peg 24 to prevent withdrawal of the spring from the peg. Spring 22 is suitably bowed so that its ends rest against, and bias downwardly, the slide [8 as described above.

The protective device i2 is in this instance the unitary thermostat l2 which is fully shown and described in the John D. Bolesky United States Patent No. 2,199,388, and attention is directed to said patent for the detailed construction and operation of this thermostat. By unitary is meant that the thermostat i2 is built as a complete device in itself, insofar as its thermostatic switching action is concerned. Briefly, thermostat [2 comprises a case having the upstanding wall 28, provided with shoulder 55, and the bottom 25. Fastened in the bottom 29 are ti'o terminal:. 30 and 3|, between which is connected a. heater element 32 and a third terminal 33 diametrically opposite from terminal 3 l. A central supporting and adjusting post 34 bears on its in per end the snap-acting disc 35 which carries the contacts 36 and 31, these contacts being welded to the disc in such position as to engage rcspectively the inner ends of terminals 33 and 3|. Mounted upon adjusting post 34 is the reset plate 38 and the reset push button 16, these last two mentioned elements being fastened together and jointly slidable toward disc 35 upon actuation of push button I6. Disc 35 is of the manual reset type, by which is meant a disc which upon being snapped by heating, will not snap back until a temperature is reached considerably lower than the temperature to which the disc is subjected in normal use. In order to reset the disc of this thermostat, the reset plate 38 must be pushed downwardly, as drawn in Fig. 11, in order to have the plate bear against the disc to manually resnap it to the position shown in Fig. 11. Button [6 serves to actuate plate 38.

The bottom part 4 of this embodiment is likewise constructed of electrical insulating material, and fits against the bottom surface of central part 3, being held in ali nment therewith by engagement of the rabbit 39, provided on the bottom edge of center part 3, with the top edge of bottom part 4. Bottom part 4 is held attached to center part 3 by screws passing through part 4 and threading into part 3. These screws are used in conventional manner and consequently their location is not described in detail here, since they do not form a part of this invention. Bottom part 4 is provided with a hole 40 axially in line with the mounting post 34 of the thermostat l2 when the latter is inserted in hole II. A cup 4| of insulating material is slidably received in hole 40 and serves to cap a spring 42 which is placed in hole 40 as shown. Spring 42 biases thermostat I2 upwardly (as drawn) and is strong enough to overcome the bias of spring 22 downwardly. Mounted on bottom 4 are the three contact arms 43, 44 and 45. Contact arms 43, 44 and 45 are of the spring type and are normally biased upwardly as shown. Contact arm 45 is mounted so that its free end is under the free end of contact arm 43. As the arms are assembled in bottom part 4, the free end of arm 43 is directly under terminal 30 of thermostat I2 and over the end of arm 45, and the free end of contact arm 44 is directly under terminal 3| of said thermostat. Contact arm 43 does not touch contact arm 45, being normally biased away from arm 45.

Illustrated by Fig. 13 is a circuit showing schematically how the switch of the present invention is connected to a motor having starting and running windings. A motor, indicated generally by numeral 46, has running winding 4'! and starting winding 43. Winding 4"I is connected by wire 49 to contact arm 43. Starting winding 43 is connected by wire 55 to contact arm 45. The other ends of windings 4'! and 48 are joined together and connected by wire 5| to one side of the power supply line. Contact arm 44 is connected by wire 52 to the other side of the power supply line.

Mechanical operation With the component parts mounted as shown in Fig. l, which is the condition of parts in which the switch may be said to be in non-operating position, spring 42 biases thermostat I2 upwardly so that the top 53 of wall 28 bears against the underside II of top part2. With thermostat I2 in this position, it will be observed that the circular inner edge 54 of slide I8 presses against the side of thermostat I2 and is thus prevented from moving to the right under the influence of spring 20. It is also to be noted that with thermostat IZ'biased upwardly as shown in Fig. 1, terminals 33 and 3| do not engage contact arms 43 and 44, nor does the free end of contact arm 43 engage contact arm 45.

Upon pushing button It downward, thermostat |2 is pushed downwardly against the bias of spring 42 until terminals 30 and 3| engage with the free ends of contact arms 43 and 44, respectively. Further downward motion of thermostat I2 will move the free ends of contact arms 43 and 44 downwardly against their normal bias until the end of arm 43 makes contact with contact arm 45 (see Figure 7), this further movement being arrested by the seating of a shoulder 55 on ledge 55. Contact arm 45 is preferably made flexible so as to be able to give slightly until the arresting of the motion of thermostat I2 as described. In addition, such further downward motion will bring top 53 of thermostat I2 below the top surface I3 of center part 3, thus allowing slide it to move to the right under the influence of spring 20 and lie between top 53 and underside I'I. Upon releasing push button It, spring 42 will urge thermostat I2 upwardly, which in turn will. carry upwardly the inner end 54 of slide I8 until slide I8 strikes underside II. With slide I8 interposed between thermostat I2 and underside i I, thermostat I2 will be held in an intermediate position, as shown in Fig. 8, in. which position terminals 3|] and 3| still engage contact arms 43 and 44, respectivel but contact arm 43 has-left contact arm 45.

In order to return the parts to their Fig. 1 position, push-button 1 may be pushedwith the result illustrated in the fragmentary section shown in Fig. 9. Upon downward pushing of button 1, cam surface 9 bears against the adjacent edge of hole I9 and cams slide I8 backward, thus withdrawing edge 54 of slide I8 from between the top 53 of thermostat I2 and underside II. Upon such withdrawal, thermostat I2 moves upwardly to the Fig. 1 position, causing terminals 30 and 3| to leave contacts arms 43 and 44.

Electrical operation When push button I6 is pushed inwardly (or downwardly as drawn), terminals 30 and 3| first make contact with arms 43 and 44. This establishes a circuit to the running winding of the motor as follows: From one side of power line by wire 52 to contact arm 44, to terminal 3|, contact 31, disc 35, contact 36, terminal 33, heater 32, terminal 30, contact arm 43, wire 49, running winding 41, and back to the other side of the power line by wire 5|. Further inward pushing results in arm 43' making contactwith arm 45, which completes a circuit to the start winding as follows: From one side of power line by Wire 52 to contact arm 44, to terminal 3 I, contact 37, disc 35, contact 36, terminal 33, heater 32, terminal 30, contact arm 43, contact arm 45. wire 50, starting winding 48, and back to other side of the power line by wire 5 I.

Thus, with button I6 pushed all the way in, both the starting and running windings are connected to the source of electrical energy. When button It is released, protective thermostat I2 will move upward, biased by spring 42, until slide It strikes underside I1. Contact arm 43 is thus allowed to leave arm 45, thus opening the circuit to the starting winding 48. As described above, slide I8 prevents further upward movement of thermostat I2, so that terminals 39 and 3| remain in engagement, respectively, with contact arms 43 and 44, thus maintaining the circuit to running winding 41.

One of the novel features of this invention is now pointed out, in respect to the slide I8 and the lost-motion provided in respect to the up and down freedom of motion permitted the end 54 by the space between surface I3 and underside II. It will be noted that in order for slide I8 to move into locking position, thermostat I2 must be pushed inwardly far enough so that contact arm 43 engages contact arm 45, that is, far enough so that the starting winding of the motor will be connected into the power circuit. However, it is also necessary that thermostat I2 move outwardly (for running operation) far enough so that contact arm 43 may leave contact arm 45, and the lost motion space referred to above is provided for that purpose. By this means, it is impossible to latch thermostat I2 into the motor running position without first having to push thermostat I 2 far enough in to connect the starting' winding.

Upon pushing button I inwardly, as described above, slide It is withdrawn, and thermostat I2 moves upwardly, thus permitting disengagement of terminals 33 and ill from contact arms 43 and 44, respectively, to disconnect the motor complete- 1y from the power circuit.

If the motor should overheat due to overload conditions, for exampleQthis heat will be conducted to the switch, if it is mounted on the motor to heat disc 35. In addition, an overloaded motor will draw more current, and this increased current will heat disc 35. Disc 35 is so calibrated, in accordance with known motor protection practies, that upon the motor approaching a dangerous temperature, disc 35 will snap to an oppositely bowed configuration, thus separating contacts 31 and 36, respectively, from terminals 3| and 33 to interrupt the current to the motor. The motor will then cool down; and disc 35 will likewise cool. However, as pointed out above, disc 35 must be manually reset by pushing on button 16, in order to reclose the circuit through thermostat I2, the above described shoulder 55 and ledge 56 acting as a solid abutment against which button l6 may react in order to reset disc 35.

It is at this point that one of the advantages of the invention becomes apparent. It would be disadvantageous to close the circuit to the running winding without at the same time closing the circuit to the starting winding. As a result of the construction of this device, wherein the button that is actuated to connect the starting winding is the same button that is actuated to reset disc 35 and reconnect the running winding, when button I is pushed hard enough to reset disc 35 to its circuit closing position, it also pushes thermostat l2 inwardly far enough to cause contact arm 43 to engage contact arm 45, thus connecting the starting winding into the circuit.

If it is found that the particular thermostat 2 has not the correct calibration to protect the motor, it is a simple matter to take off top part 2, remove thermostat l2 and substitute another thermostat of different calibration. Similarly, in the event of burn-out or other failure of thermostat 12, it is a simple and relatively inexpensive repair job to remove the defective thermostat and put in a properly operating one, without having to replace the other parts of the switch mechanism.

Referring now to Figs. 12 and 14, there is shown a modification of the bottom part of Fig.

5, and the circuit in which this modification may be used. In this instance, contact arms 43 and 45 are not arranged so that the free end of arm 43 will touch, upon being deflected, contact arm 45. Instead, contact arm 45 is removed from underneath arm 43 and is so placed relative to thermostat l2, that the deflectible end of arm 45 is engageable by terminal 33 of thermostat l2, terminal 33 in this instance being made so as to project from the base 29 of thermostat 12 as do terminals 30 and 3|. Contact arms 43, 44 and 45 are so arranged that as thermostat I2 is pushed inwardly, arms 44 and 45 are engaged by (respectively) terminals 3| and 33 first, and upon further inward movement of thermostat |2, terminal 30 engages arm 43.

Referring to Fig, 14, a wiring diagram for this embodiment is illustrated as follows: One end of starting Winding 48 is connected by wire 51 to contact arm 43. One end of running winding 41 is connected by wire 58 to arm 45. The common connection between the other ends of these windings is connected, as before, by wire 5| to one side of the power supply line; and the other side of the power supply line is connected, as before, by wire 52 to arm 44.

With the connections thus made, the arrangement operates as follows: When button I6 is pushed to move thermostat |2 inwardly, terminals 3| and 33 first engage arms 44 and 45, respectively, to allow current to flow to running winding 4'! through wire 52, arm 44, terminal 3|, contact 31, disc 35, contact 36, terminal 33, arm 45 and wire 58. Further inward motion of thermostat l2 causes terminal 30 to engage arm 43 to allow current to flow to starting winding 48 through wire 52, arm 44, terminal 3|, contact 31, disc 35, contact 36, terminal 33, heater 32, terminal 30, arm 43, and wire 51. When the motor has come up to speed, button I6 is released, and thermostat |2 will move upwardly until stopped by the slide member I8 as described for the Fig. l embodiment. In this position, terminal will have left arm 43, thus opening the circuit to the starting winding, while terminals 3| and 33 will still engage arms 44 and respectively, thus maintaining the circuit to the running winding.

The protecting, resetting, and start and stop functions of this embodiment are the same as described above for the Figs. 1 and 5 embodiment, with all the attendant advantages, the only difference being that in this arrangement, the heater 32 may function only while terminal 30 is engaging arm 43, that is, while the starting winding is in the circuit. This is a desirable arrangement for some types of motors.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results obtained.

As many changes could be made in the above construction and arrangement or" parts without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying draw ings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A combined starting and protective switch for an electrical motor, comprising a first base, first contact means carried by said base, unitary protective means carried by said base and movable from a non-contact-making position to two contact-making positions, said protective means comprising a second base with second contact means mounted thereon and manually resettable current responsive means carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means electrically engaging said first contact means when said protective means is in one of its said positions and being electrically disengaged from at least one of said first contact means when said protective means is in another of its positions, and latch means operable to hold said protective means in said one position.

2. A combined starting and protective switch for an electrical motor, comprising a first base, contact means in said base, movable contact means in said base for cooperating with said contact means, unitary protective means carried by said base and movable from a non-contactmaking position to two contact-making positions said protective means comprising a second base with contacts mounted thereon and manually resettable thermally responsive means carried by said second base for electrically connecting and disconnecting said contacts, one of said contacts being adapted electrically to engage said movable contact means when said protective means is in one of its positions in the first base and being electrically disengaged therefrom when said protective means is in another of its positions, and latch means operable to hold said protective means in said one position.

3. A combined starting and protective switch for an electrical motor, comprising a first base, first contact means carried by said base, a first movable contact arm carried by said base and cooperable with said first contact means to make and break an electrical circuit, a second movable contact arm carried by said base, unitary protective means carried by said base and movable to occupy three positions in said base, said protective means comprising a second base with second contact means mounted thereon and manually resettable thermally responsive means carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means being adapted to engage said first and second movable contact arms when said protective means is in two of said three positions, said first movable contact arm being adapted to engage said first contact means carried by said first base when said protective means is in one of said two positions, and latch means operable to hold said protective means in the other of said two positions.

4. The device of claim 3, wherein said manually resettable thermally responsive means comprises a thermally responsive element and manual means for actuating said element, said manual means being adapted, upon actuation thereof, to move said protective means into said one position.

5. A combined starting and protective switch for an electrical motor, comprising a first base, first contact means carried by said base, unitary protective means carried by said base and movable from one position to another position, said protective means comprising a second base with second contact means mounted thereon and manually resettable thermally responsive means carried by said second base for electrically con necting and disconnecting said second contact means, said second contact means electrically engaging said first contact means when said protective means is in one of its said positions and being electrically disengaged from at least one of said first contact means when said protective means is in another of its positions, and latch means operable to hold said protective means in said one position, said protective means being associated with lost motion space whereby said latch means is inefiective to hold said protective means in said one position until said protective means has traversed said space.

6. The device of claim 5, wherein said manually resettable thermally responsive means comprises a thermally responsive element and manual means for actuating said element, said manual means being adapted, upon actuation thereof, to move said protective means into said one position.

'7. A combined starting and protective switch for an electrical motor, comprising a first base, first contact means carried by said base, unitary protective means carried by said base and movable from one position to another position, said protective means comprising a second base with second contact means mounted thereon and manually resettable thermally responsive means carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means electrically engaging said first contact means when said protective means is in one of its positions in the first base and being electrically disengaged from at least one of said first contact means when said protective means is in another of its positions, and latch means operable to hold said protective means in said one position, said latch means comprising a, plate slidable toward and away from said protective means and interposable between said protective means and a portion of said base.

8. A combined starting; and protective switch.

for an electrical motor, comprising a first base, first contact means carried by said base, unitary protective means carried by said base and movable from one position to another position, said protective means comprising a second base with second contact means mounted thereon and manually resettable thermally responsive means carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means being adapted electrically to engage said first contact means when said protective means is in one of its positions in the first base and being electrically disengaged from at least one of said first contact means when said protective means is in another of its positions, and latch means operable to hold said protective means in said one position, said latch means comprising a plate slidable toward and away from said protective means and interposable between said protective means and a portion of said base, said protective means being associated with lost motion space whereby said latch means is ineffective to hold said protective means in said one position until said protective means has traversed said space.

9. The device of claim 8, wherein said manually resettable thermally responsive means comprises a thermally responsive element and manual means for actuating said element, said manual means being adapted, upon actuation thereof, to tmove said protective means into said one posi- 10. A combined starting and protective switch for an electrical motor, comprising a first base, first contact means carried by said base, a first movable contact arm carried by said base and cooperable with said first contact means to make and break an electrical circuit, a second movable contact arm carried by said base, unitary protective means carried by said base and movable to occupy three positions in said base, said protective means comprising a second base with second contact means mounted thereon and a manually resettable snap-acting thermostat element carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means being adapted to engage said first and second movable contact arms when said protective means is in two of said three positions, said first movable contact arm being adapted to engage said first contact means carried by said first base when said protective means is in one of said two positions, and latch means operable to hold said protective means in the other of said two positions.

11. A combined starting and protective switch for an electrical motor, comprising a first base, first contact means carried by said base, a first movable contact arm carried by said base and cooperable with said first contact means to make and break an electrical circuit, a second movable contact arm carried by said base, unitary protective means carried by said base and movable to occupy three positions in said first base, said protective means comprising a second base with second contact means mounted thereon and manually resettable thermally responsive means carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means being adapted to engage said first and second movable con tact arms when said protective means is in two of said three positions, said first movable contact arm being adapted to engage said first contact means carried by said first base when said protective means is in one of said two positions, and latch means to hold said protective means in the other of said two positions, said protective means being associated with lost motion space whereby said latch means is ineffective to hold said protective means in said other position until said protective means has been first moved to said one position.

12. The device of claim 11, wherein said manually resettable thermally responsive means comprises a thermally responsive element and manual means for actuating said element, said manual means being adapted, upon actuation thereof, to move said protective 1r. ans into said one position.

13. A combined stai ig and protective switch for an electrical motor, comprising a first base, first contact means carried said base, a first movable contact ai carried by said base and ccoperable rst contact means to make and bree' contact tive means occupy three tective means com i by said base, unitary proteccarried by base and movable to positio s in said first base, said prosing a second base with sec- 0nd contact means mounted thereon and mani ually resettable thermally responsive means carried by s second base for electrically connecting and disconnecting said second contact mean said second contact means being adapted to engage said first and second movable contact arms when said protective means is in two of said three positions, said first movable contact arm being adapted to engage said first contact means carried by said first l ase when said protective means is in one of said two positions, and latch means opera .c to hold said protective means in the other of said two positions, said latch means comprising a plate slidable toward and away f om said protective means and interposable between said protective means and a portion of said base, said protective means being associated with lost motion space whereby said latch means is incifective to hold protective means in said other position until said protective means has been first moved to said one position.

14. The device of claim 13, wherein said inanually resettable thermally responsive means coinprises a thermally "esponsive element and manual means for actuating said element, said manual means being adapted, upon actuation thereof, to move said protective means to said one position to permit said latch to move into holding position.

15. A combined starting and protective switch for an eectrical motor, comprising a first base, first contac means carried by said base, unitary protective carried by said base and movable irom one position to another, said protective means comprising a second base with second contact means mounted thereon and manually re settable thermally responsive means carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means electrically engaging said first contact means when said protective means is in one of its positions in the first base and being electrically disengaged from at least one of said first contact means when said protective means is in another of its positions, said manually resettable thermally responsive means comprising a thermally responsive element and manual means for actuating said element, said manual means, upon actuation thereof, being adapted to move said protective means into said one position, and latch means operable to hold said protective means in said one position.

an electrical circuit, a second movable 16. A combined starting and protective switch for an electrical motor, comprising a first base, first contact means in said base, movable contact means in said base for cooperating with said first contact means, movable unitary protective means in said base, said protective mean. comprising a second base with contacts mounted on said second base and manually resettable thermall responsive means carried by said second base for electrically connecting and disconnecting said contacts, at least one or" said contacts being adapted electrically to engage said movable contact means when said protective means is in one of its positions in said first base and being electrically disengaged therefrom when said protective means is in another of its positions, said manually resettable thermally responsive means comprising a thermally responsive element and manual means for actuating said element, said manual means being adapted, upon actuation thereof, to move said protective means into said one position, and latch means operable to hold said protective means in one position.

17. A combined starting and protective switch for an electrical motor, comprising a base, first contact means carried by the base, a first movable contact a in car led by the base and cooperable with said first contact means to make and break an electrical circuit, a second movable contact carried by the base, a recess in the base, unitary protective means slidably mounted in said recess, said protective means comprising a cup with second contact meanslnounted on the bottom thereof and a manually resettable snapacting thermostat element mounted therein and adapted electrically to connect and disconnect said second contact means, said second contact means being adapted electrically to engage said first and second movable contact arms respectively and to cause said first movable contact arm electrically to engage said first contact means carried by said base when said protective means is moved to one end of said recess, at least one of said contact means being disengaged from said movable contact arms when said protective means is at the other end of said recess, and latch means carried by the base and operable to hold said protective means in a position intermediate the ends of the recess.

18, A combined starting and protective switch for an electrical motor, comprising a base, first contact means carried by the base, a first movable contact arm carried by the base and cooperable with said first contact means to make and break an electrical circuit, a second movable contact arm carried by the base, a recess in the base, unitary protective means slidably mounted in said recess, said protective means comprising a cup with second contact means mounted on the bottom thereof and a manually resettable snapacting thermostat element mounted therein and adapted electrically to connect and to disconnect said second contact means, said second contact means being adapted electrically to engage said first and second movable contact arms respectively and to cause said first movable contact arm electrically to engage said first contact means carried by said base when said protective means is moved to one end of said recess, at least one of said second contact means being disengaged from said movable contact arms when said protective means is at the other end of said recess, and latch means carried by said first base and operable to hold said protective means in a position intermediate the ends of the recess, said latch means comprising a plate slidablc toward and away from said protective means and inter= posable between said protective means and a portion of said base.

19, A combined starting and protective switch for an electrical motor, comprising a base, first contact means carried by the base, a first movable contact arm carried by the base and c operable with said first contact, means to make and break an electrical circuit, a second movable contact arm carried by the base, a recess in the base, unitary protective means slidably mounted in said recess, said protective means comprising a cup with second contact means mounted on the bottom thereof and a manually resettable snapv acting thermostat element mounted therein and adapted electrically to connect and to disconnect said second contact means, said second contact means being adapted electrically to engage said first and second movable contact arms respectively and to cause said first movable contact arm electrically to engage said first contact means carried by said base when said protective means is moved to one end of said recess, at least one of said contact means being disengaged from said movable contact arms when said protective means is at the other end of said recess, and latch means carried by said first base and operable to hold said protective means in a position intermediate the ends of the recess, said latch means comprising a plate slidable toward and away from said protective means and interposable between said protective means and a portion of said base, said protective means being associated with lost motion space whereby said latch means is ineffective to hold said protective means in said intermediate position until said protective means has been first moved to said one end of the recess.

20. A combined starting and protective switch for an electrical motor, comprising a first base, first con-tact; means carried by said base, unitary protective means carried by said base and mov able from one position to another with respect to the base, said protective means comprising a second base with second contact means mounted on said second base and manually resettable thermally responsive means carried by said second base for electrically connecting and disconnecting said second contact means, said second contact means being so arranged on said second base as to engage electrically with said first contact means when said protective means is in one of its positions with respect to the first base but to be electrically disengaged from at least one of said first contact means when said protective means is in another of its positions, said anually actuable means for resetting said hermally responsive means being adapted upon actuation to move said protective means to said he position, latch means carried by said first base and operable to hold said protective means n said one position, and manually actuable neans for moving said latch means in an unocking direction.

21. In aco'mbination starting and protective Witch for an electrical motor, a base, cooperating electrical first contact means mounted on the base, self-contained and replaceable protective means carried by said base and movable with respect to said first contact means, said protective means mounting in itself both second contact means and manually resettable thermally responsive means for electrically connecting and disconnecting said second contact means, said manual means for resetting said thermally responsive means being adapted for moving said protective means in order to bring said second contact means into electrical engagement with said first contact means, and latch means for holding said first and second contact means thereafter in engagement.

22. A combined starting and protective switch for an electrical motor, comprising a first base, first, second and third first base contact means carried by said base, unitary protective means movably mounted in said base, said protective means comprising a second base also carrying first, second, and third second base contact means, a manually resettable thermally responsive means carried by said second base and adapted to electrically connect and disconnect two of said second base contact means, said second base contact means being adapted to make electrical contact with said first base contact means when said protective means is in a first position in the first base but .to make electrical contact with only two of said first base contact means when said protective means is in a second position in said first base, and latch means operable to hold said protective means in said second position.

23. A combined starting and protective switch for an electrical motor comprising a first base, first, second and third first base contact means carried by said base, unitary protective means mounted in said base, said protective means also carrying first, second and third second base contact means, and. manually resettable thermally responsive means adapted electrically to connect and disconnect two of said second base contact means, said unitary protective means being movable into a plurality of positions in respect to said base whereby, in a first position each or said second base contact means engages one of said first base contact means, in a second position only .two of said second base contact means engage the respective two of said first base contact means, and in a third position not more than one of said second base contact means engages a first base contact means, and latch means operable to hold said protective means in said second position.

VICTOR G. VAUGHAN. ROBERT G. MAWNE-Y. JAMES A. BAGNALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,120,223 Murray Dec. 8, 1914 2,199,388 Bolesky May 7, 1940

Images