US1491244A - Double-throw fuse motor-starting switch - Google Patents

Description

April 22, 1924.

l l l 1111111 J 1 lllllllllllllllll -ll- IIIIIIIIIIIIIIIII Il lllldldlll lift!!! G E PALMER DOUBLE THROW FUSE MOTOR STARTING SWITCH Filed Jan; 8, 1919 IIIT l I I I l l I l I! A15491.244 l s. E. PALMER f DOUBLE THROW FUSE MOTOR STARTING SWITCH April 22, 1924;

Filed Jan. 8, 1919 4 Sheets-Sheet 2 April 22, 1924.

Filed Jan. 8, 1919 4; Sheets-Sheet 5 r llllllll llt,

und

April 22, 1924. 1,491,244

- G. E. PALMER DOUBLE THROW FUSE MOTOR sTARTINO SWITCH Filed Jan. 8, 1919 4'Sheets-Sheet 4 @511.1111 ll\\ I( 1| lPatented Apr. 22, 1924.

l Y 1,491,244. `iJNiriiiJ s'rAl'rEs PATENT orricE.

GRANVILLE P-AJZIEB, l' BOSTON, IKASSACHUSITTS, yASSIGN'QBTO THE PALm ELECTRIC IANUFACTUBING COMPANY. 0F BOSTON, MASSACHUSETTS, A. COB- ron'noiw or im.

I 'DOUBLE-THEOW FUSE KOTOR-STARTING application ma mmm-y s, isis. semi navals.

i To all whom it may, concern:

Be it known that I, GixANviLE E. PALMER,

a ,c itizen' of the United States, residi at Boston, in the county of Su'olk and tate of Massachusetts, have invented new and useful Improvements in Double-Throw Fuse Motor-Starting Switches, of which the following is a specification.

The Vobject of this invention is to rovide l0 a simple double-throw switch for po` y hase induction-motor circuits, so constructe and arranged that,l before thel current is suplied continuously to the motor through uses of proper capacity, a startin `current is supplied by moving a movab e switch member into a position which closes the circuit between the terminals but from which it moves automatically to running position on being released by the operator. In such starting switches, mechanism should be provided for preventing the initial rclosure of the circuits through the working fuses. The high amperage, temporarily .occasioned by closing t e motor circuit, would require fuses of such ca acity that the subsequent inclusion of suc fuses in the working circuit would cause their failure to respond to overloads during the normal operation of the motor.

In accordance with the present invention, I provide a sliding carrier onY which the fuses are mounted, the terminals of which, when the carrier is in one position, are engaged and electrically connected with the live terminals of the| circuit. The carrier is provided with a second set of connectedl terminals, which, when the carrier is in another position, are engagedy and electrically connected with the stationary live contacts so as temporarily to close the motor circuit and i provide the starting current. The carrier is so constructed and operated that, before the fuse terminals can be brought into electrical contact with the stationary contacts, it is necessary first to"move the carrier into position to sup 1y the starting current, after which the re ease of the carriercauses it automatically to assume a position in which the fuses and their terminals are moved into so operative position.

The starting switch as a whole comprises a metallic case in which all of the operative Karts. with the exception of an oscillatory andle, are located. The front wall of the through the '-with the necessaryk overlap in case is provided with anopening throughl which, under certain conditions, access. may

be had to the fuses on the carrier. Associated with the opening is a'slidable door which may be moved to open ositon to afford access to the fuses, an interlocking mechanism between lthe door and the actuator for the fuse-carrier is provided for the purpose of lpreventing the opening of the door except w en the fuse carrier is in its neutral inactivieposition and by which the door is preven from being opened when the fuse carrier is in a position in which the circuits are closed between ther stationary contacts. The switch. carrier is actuated by a rock shaft and a` toggle connectin the shaft with the carrier, the to gle icing so arranged that, when the switc carrier is in its normal closed position with the fuses carrying ythe current, the carrier is locked. thereby against accidental yopening movement. l 7

vOn the accompanying drawings,- Figure 1 represents in front elevation a starting switchlembdying the invention.v

Figure 2 represents a longitudinal section,

through the same.

" Figure 3 re resentsa through the sliding door carrier thereby- Figure 4 shows the switch mechanism transverse section l ont wall of the oase and with the front wall removed, and illustrates v the motor circuit diagrammatically.

Figure 5 illustrates the normal open position of the fuse carrier, the fuses and terminals being omitted from the drawin Figure 6 shows the first position to iv iich the fuse carrier is moved to supply the starting current to the motor. i

Fi re 7 shows the final operative closed position of the fuse carrier.

The case or box is preferably madeof sheet metal and comprises the rear wall 10, the side walls 11, the top and ` bottom walls 12 and 13, and the front wall 14. These are stamped out of sheet metal and are provided flanges which are riveted together. e ront wall `14: is preferably removable so as to afford access to the entire interior of the box. The case, as is customary, is, provided with the usual knockout plu so that the conductor wires may be carried into the box. The front wall or cover 14 of the box is provided 'impossible to actuate the i ick shaft.

with an opening 15 normally closed by `a. door 16 movable laterally in guides 17, 17, affixed to the rear of the cover. The door` at its upper end has a flange 18 overlapping the guide 17, and at its lower end it has an elongated inwardly-projeotin flange 19 for a purpose to be described. oo'ated within the box or case, there is a frame consistin of a base plate 20 and upper and lower en walls 21, 22, secured thereto, this frame being bodily removable from the case so as to carry with it the mechanism supported thereby. Upon the base plate are secured two parallel blocks 23, 23, of slate, compressed fiber, or other insulating material. These blocks are located beyond the side edges of the opening in the cover. Upon the blocks are secured the stationary terminals or contacts 24, 25. As shown in Figure 4, they are arranged in pairs. Each contact may be made in any suitable way so that a conductor wire may be secured thereto by a binding screw 26, and each is provided with an upright member 27 with which the movable contact may be engaged. The member 27 may be formed separately and secured to the member 24, 25, by a screw 28 as shown.

A movable fuse carrier 30 is arranged between the blocks 23, 23, and is itself formed of insulating material. This carrier is secured upon a metal plate 31 (see Figure) which is vertically and longitudinally movable between guides 32 formed on or secured to the base plate 20. The fuse carrier, when inoperative or open, occupies the lposition shown in Figure 5, but it may be moved up-v wardly or downwardly therefrom as will be explained. The mechanism for actuating the carrier comprises a rock shaft 33, the inner reduced end of which is journaled in the base plate 20 and the forward end of which is journaled in a bracket 34 secured to the lower end plate 22 of the frame in the case. This shaft is formed or provided with an arm 35, between which and the carrier or the plate 31 thereof is located a curved link 36 pivotally connected to the plate 31 by a pivot 37 and pivotally connected to the arm 35 by a pivot or pintle 38. The front end of the shaft 33 projects through the front wall or cover 14 of the case, and has secured upon it by a screw 39 an operating handle 40 provided with a knob 41. On the shaft there is a cam 42 having a flattened face 43, which, when the shaft and handle are in the position shown in Figure 1, is parallel to the flange 19. This latter flange 19 has, however, an inward extension 119, which, when the door 16 is moved to the right, slides across the flat face of the cam and prevents the cam from being rotated; and consequently, when the door is open, it is When the door is closed and the operating handle with a plurality of pairs of fuse terminalsl equal in number to the pairs'of stationary contacts 24, 25, on the blocks 23. Each pair of fuse terminals, which are indicated at 44,

is Provided with spring clips 45 to receive a use 46, and each is also provided with a sprin may e brought into electricalengagement and contact with the nearest stationary contact member 27. The spring contacts 47 are below the associated contact members 2T, so that, to cause their engagement, it is necessary to move the sliding carrier vertically to the u per limit of its movement. When this has Ibeen done, the circuit is closed permanently to the'motor through the fuses. For the purpose of supplying a starting current,however. the carrier 30 is provided with another set of contact members which are arranged in pairs as at 48, 48, each pair being connected by a metal conductor 49 extending across the face of the carrier. These spring contacts 48 are respectively above the associated stationary contacts 27 so that, in order to engage them, it is necessary to move the carrier downwardly. Thus 1t is apparent from the foregoing description that the normal operation of the switch mechanism to close the circuit through the motor would be first to move the carrier downwardly to bring the contacts 48 into engagement with the contacts 27 to supply the starting current, and then to move the carrier vertically upwardly until the contacts 47 are brought in Contact with the stationary contacts 27.

l provide mechanism for insuring that the operation of the switch mechanism shall be accomplished in the manner described and not otherwise, so that it is impossible to close the motor circuit initially through the fuses and the associated contacts 47.

50, which, when the fuse carrier is in its iu- The `cam 42 is provided with a tooth or shoulder brush or contact member 47 which 69 on a pawl 51 pivoted b v a screw pin 52 to a bracket 53 secured to the end plate 22. A spring 54 holds Athe pawl in engagement with the cam, which in this instance serves as a one-toothed ratchet. When the parts are in the position shown in Figures 4 and 5, the shaft 33 cannot be rotated clockwise so as to move the carrier upwardly and bring the fuse terminals into engagement with stationary contacts 27 The rock shaft, howmana-1.4,

the carrier downwardly and bring the electrically-connected terminals or spring contacts 48 into engagement with the stationary eon.

taets 27. The link 36 and arm. 35 are so formed that Lthe link engages the shaft. during the anti-clockwise movement .of the shaft, before the parts reach a dead-center position, and thus prevents the carrier from being locked 'in its lowermost position; and also a stop 154 is located in the path of the arm 35, as shown in Figure 6, vfor the same purpose. I provide means for insuring that, when the shaft 45 has been rocked anti-clockwise to cause the initial engagement of the spring contacts 48 with the stationary contacts 27, on release of the operative handle. the carrier will movey automatically vinto position to cause the final closing of the motor circuits through the fuses by the engagement of thecontacts 47 with the stationary contacts 27. On the base plate 20v are secured two flanged brackets-55, 56, to which are secured the guide rods 57, 58, respectively. Theplate 31 of,

the carrier hasthe two brackets 59 and 60 respectively,- which are in slidingcontact with the guide rods 57, 58. On the rod 57 there is the helical compression spring 61, and on the rod 58 there is a like compression spring 62. The rod 58 projects upwardly beyond the bracket 6() and is provided at its upper end with a nut 63. A shock absorbing spring 64 is located between the nut 63 and the bracket 60. When the carrier is moved to its lowermost position, shown in Figure 6, the springs 62, 61 are compressed and sufficient power is stored therein, on release of the carrier, to move it quickly to its uppermost position as shown in Figure 7. The spring 64 serves to take up the shock of the carrier and gradually stop 1t. In order that the carrier may be locked in its uppermost position, the toggle, consisting ofthe arm 35 and the link 36, should move just beyond dead-center sition, and, to hold the parts in this position, the link 36 is provided with a stop 65 for engaging the arm 35. To ensure that the parts will move slightly lvpast their dead-center position. I.

employ a tension spring 66, one end of which is? secured to the plate 31 and the other end of which is secured to a lug 67 projecting laterallv from the link 36 to one side of the pivot 37.

When the carrier has been moved downwardly by the actuating handle to throw the starting current on the` line, it is necessary forfthe operator to maintainl his hold upon the handle. When the handle is released` however, the carrier is moved upwardly bv the springs so as to effect a quick make of the contacts. If the operator should restrain the upward movement o f the carrier,

the pawl would engage the-tooth 50 of the cam and prevent the further movement of the carrier. In order, however, that the carrier may be permitted to move rapidly to its uppermost position, the cam is provided with a projection 68 which engages ,the pawl as the cam rotates clockwise, and throws the pawl outwardly on its pivot. The projection is located fairly close to the tooth', and the pawl is thrown outward with sufficient force when the cam strikesl the pawl so that the element of time required for its outward and inward movement is sufiicient to permit the tooth 5()v to pass by the shoulder 69 on the pawl without being engaged thereby. This action is entirely automatic, and all that is necessary for the operator to do is to release the handle, when the parts are inthe position shown in Figure 6, for the carrier to move` automatically into its closed position and there become locked by the toggle mechanism. To break the circuit through thefuses, the operator moves the handle anti-clockwise, and the carrier comes to a state of rest ,in the position shown in Figure 5. The springs 61, 62 and 64 normally hold u the fuse carrier in the neutral or open position.

On the front of the cover I iix a segmental plate 7() with which cooperates a pointer 71 attached to the shaft 33. On the segmental plate I place the Words Start and Run and between them the word Oft These symbols indicate theseveral positions which are assumed by the rock shaft and the carrier; that is, the position to supply the starting current, the position to supply the current continuously through the fuses, and the intermediate neutral or inactive position of the' carrier with both sets of movable contacts disengaged from the stationary contacts.

It is highly desirable that all of the live current-carrying terminals should be carefully guarded from access through thek door-v closed opening, and therefore I locate between the side edges of the doory andthe stationary contacts, barriers of insulating material which extend substantially to the front cover and shut of access through the opening to the stationary contacts. These barriers consist of parallel plates or walls 73, 7 3, which are attached to the sides of the tacts 48 and 47 project through apertures f formed in the walls or partitions. When the door is moved to open position, the fuses are easily accessible and are exposed through the opening, and an operator may change or remove the fuses without danger'of coming into contactwith any of the current-carrying fuses.

It is of course quite evident that, in lieu 0f connecting each pair of contacts 48., 48, by'

a permanent connection 49, I may substitute for the latter removable. fuses capable of carrying the high potential starting current, but, for ordinary purposes, this is unnecessary.

It may be stated that the case Should be arranged vertically when in use, the springs being of such length and strength as normally to hold the carrier in its neutral open position. When the operator turns the handle anti-clockwise to the start position, the springs G1, 62, are compressed and the spring cont-acts 48 are under tension, and

hence, on releasing the handle, the carrier is forced upwardly and its acquired momentum is such that the contacts 47 are brought into tensioned engagement with the stationary contacts 2T. The power of the springs 6l and 62 is so regulated, however, that the carrier will not be forced thereby into the closed run position unless it has been moved to a position with the contacts 48 under tension, before being released. Unless the cam acquires such speed as to throw the pawl the requisite distance to the right, the pawl will engage the tooth on the cam and prevent the movement of the carrier upwardly from its neutral open position.

Having thus explained the nature of my said invention and described a way of making and using the same, although without attempting to set forth all of the forms in which it may be made or all of the modes of its use, whatl I claim is l. A double-throw switch comprising a pair of stationary contacts, a carrier between said contacts and having two pairs of movable contacts arranged alternately to engage the stationary contacts. a fuse connectingr one pair of movable contacts, an electrical connection between the other pair of movable contacts, yielding' means for holding said carrier in a neutral open position with both pairs of contacts out of engagement with the stationary contacts, a rock shaft, and a toggle connecting said rock shaft and said carrier.

2. A double-throw switch comprisingr a pair of stationary contacts, acarrier between said contacts and having two pairs of movable contacts arranged alternately to engage the stationary contacts, a fuse connecting one pair of movable contacts, an electrical connection between the` other pair of movable contacts, a rock shaft, a toggle connecting said rock shaft and said carrier and arranged when said rock shaft is moved in one direction to move the carrier in a direction to bring the electrically-connected contacts into engagement with the stationary contacts, and spring mechanism for moving said carrier in the opposite direction to bring the `fuse connected contacts into engagement with the stationary contacts, said toggle being constructed and arranged to lock said carrier in its last-mentioned position.

3. A double-throw switch comprising a pair of stationary contacts, a carrier having two pairs of movable contacts adapte alternately to engage the stationary contacts, an' electrical connection between one pair of movable contacts, a.. fuse connecting the vmovable contacts of the other pair, a rock shaft, a toggle operatively connecting the rock shaft and the carrier and adapted to lock the carrier with the fuse-connected contacts in engagement with the stationary contacts, spring mechanism normally holding said carrier in` neutral position with the contacts thereon out of engagement with the stationary contacts, and arranged by the power stored therein when the carrier is moved in one direction to move the carrier automatically in the other direction to bring the` fuse-connected contacts into engagement. with the stationary contacts, and pawl and ratchet mechanism for preventing the movement of the carrier from neutral position directly to the last-mentioned position.

4. A double-throw switch comprising a pair of stationary contacts, a movable carrier having two pairs of contacts thereon,

one pair being fuse-connected and the other' pair being electrically-connected, a rock shaft, a toggle connecting said shaft with said carrier, a spring-pressed pawl, and a toothed member on said shaft having a cam projection for moving said pawl temporarily into inactive position.

5. A double-throw switch comprising a pair of stationary contacts, a movable carrier having two pairs of contacts thereon, one pair being fuse-connected and the other pair being -electrically-connected, a rock shaft, a toggle connecting said shaft "with said carrier, a spring-pressed pawl, a toothed member on said shaft having a cam projection for moving said pawl temporarily into inactive position,and spring-actuatingmechanism normally holding the carrier in an intermediate or neutral openposition, and adapted when power is stored therein by movement of the rock shaft to move said carrier to a position in which the fuse-connected contacts are engaged with the stationary contacts.v

6. A double-throw switch comprising a pair of stationary contacts, a movable carrier having two pairs of contacts thereon, one pair above the stationary contacts and the other pair below the same, a. fuse connecting one pair of said movable contacts, an electrical connection between the other pair of movable contacts, spring mechanism normally holding said carrier in an intermediate or neutral open position but adapted to'move said carrier from one extreme position to its other extreme position,

switch comprising a case having an opening in its front wall, and provided with a door associated with said opening, insulating blocks aixed in the case and arran ed on both sides of the opening, a plura it of pairs of stationary contacts mounts on said blocks, a movable carrier arranged between the contacts of said pairs of stationary contacts and o posite said opening, a plurality of pairs o fuse-connected contacts on the carrier adapted, when said carrier is at one extreme position, to engage the stationary contacts, a plurality of pairs of electrically-connected contacts on the carrier adapted when the carrier is at the other extreme position to engage said stationary contacts, and partition walls 0r barriers located between the stationary contacts and the opening in the case to prevent access to said stationary contacts when the door is moved to open position while permitting access to the fuses and contactlconnections of said carrier. j

8. A double-throw fuse motor-starting switch comprising a case having an opening in its front wall, and provided with a door associated with said opening, insulating blocks affixed in the case and arranged on both sides of the opening, a plurality of pairs of stationary contactsmounted on said blocks, la movable carrier arranged between the contacts of saidpairs of stationary contacts, a plurality of pairs of fuse-connected contacts on the carrier adapted, when said carrier is at one extreme position, to engage the stationary contacts, a plurality of pairs of electrically-connected contacts on the carrier adapted when the carrier is at the other extreme position to engage said stationary contacts, partition walls or barriers located between the stationary contacts and the opening in the case to prevent access to said stationary contacts when the door is moved to open position and through openings in which said carrier contacts extend, and mechanism for positively locking said carrier in an intermediate neutral position when the door is opened.

9. A. double-throw fuse motor-starting switch comprising a case having an opening in its front wall, and provided with a door associated with said opening, insulating blocks affixed in the case and arranged on both sides of the opening, a pluralit of pairs 'of stationary contacts mounted1 on said blocks, a movable carrier arranged between the contacts of said pairs of stationary contacts, a plurality of pairs of fuse-connected contacts on `the carrier adapted, when said carrier is at one extreme position, to engage the stationary contacts, a plurality of pairs of electrically-connected contacts on the carrier adapted when the carrier is at the other extreme position to engage said stationary contacts, partition walls or barriers located between the stationary contacts andthe opening in the case to prevent access to said stationary contacts when the dolor is moved to open position and through which said carrier contacts extend, a manually-operable device for moving said carrier into position to bring the electricallyconnected contacts into engagement with the stationary contacts, spring mechanism y arranged on release of said manually-operable device to move said carrier into position to bring the'fuse-connected contacts into engagement with the stationaryk contacts, and interlocking mechanism between said door and said manually-operable' device whereby lsaid device is locked against movement by both said device and said spring mechanism when the door is open. p

10. A double-throw switch comprising a casing, a pair of stationary contacts therein, a carrier therein havin thereon and movv able Vtherewith two pairs of contacts for alternately engaging said stationary contacts and adapted to assume a neutral position with the contacts thereof disengaged from the stationar contacts, a fuse connecting one pair o said movable contacts,

an electrical connection between the other pair of movable contacts, a door normally covering said fuse, and interlocking mechanism intervening between said door and carrier and locking the door except when said carrier is in neutral position.

11. A double-throw switch comprising a casing, a pair of stationary contacts therein, a carrier therein havin thereon and mov- 'able therewith two palrs of contacts for alternately engaging said stationar contacts and adapted to assume a neutra position with the contacts thereof disengaged from the stationary contacts, a fuse connecting one pair of said movable contacts, an electrical connection between theother pair of movable contacts, a door normally covering said l fuse, interlocking mechanism intervening between said door and carrier and locking the door except when said carrier is in neutral position, and means permitting the movement of said movable contacts and concealing said stationary contacts and preventin access tosaid stationary contacts when t e door is open.

l2. A double-throw switch comprising a movable carrier havin two pairs of contacts movable therewit a fuse connecting one pair of contacts, an electrical connection between the other pair of contacts, a pair of stationary contacts arranged between and adapted to be engaged by the pairs of movable contacts, a casing enclosing said elements and having a movable door, and means for preventing access to said stationary contacts when the door is open.

13. A double-throw switch comprising a movable carrier havi two pairs of contacts movable therewith, a fuse connecting one pair of contacts, an electrical connection between the other pair of contacts, a pair of sta-tionar contacts arran ed between and adapted to engaged b t 1e pairs of movable contacts, a casing enc osing said elements and having a movable door, and means for preventing access to said Stationary contacts when the door is open, said fuse being located on said carrier in the rear of said door and accessible when the door is open.,

14. A double-throw switch comprising a -movable carrier having two pairs of contacts movable therewith, a fuse connecting one pair or" contacts, an electrical connection between the other pair of contacts, a pair of stationary) contacts arranged between and adapted yto e engaged by the pairs of movable contacts, a casing enclosing said elements and having a movable door, means for preventing access to said stationary con- 1 tacts when the door is open, said fuse being located cn said carrier in the rear of said door and accessible when the door is open, and interlocking means between the door and the carrier by which the carrier is ositively locked in an intermediate neutra position when the door is open.

15. A switch comprising a casing having a door opening therein, a carrier movable in said casing opposite said door opening, two pairs of contacts movable with said carrier, a fuse connecting one of said pairs of contacts, an electrical connection between the other pair of contacts, said fuse and connection being accessible through said opening, a pair of stationary contacts arranged between said movable contacts at opposite sides of said door: opening and adapted to be engaged by said pairs of movable contacts, and barriers extending from the margins of said door opening and preventing access to said stationary contacts from said door opening.

16. A switch comprising a casing having a door opening therein, a movable door for closing said opening, a carrier movable in said easing opposite said door opening, two pairs of contacts movable with said carrier, a fuse connecting one of saidv pair of contacts, and electrical connection between the other pair of said contacts, said fuse and connection being accessible through said opening when the door is open, a pair of sta' tionary contacts arranged between said movable contacts at opposite sides of said door opening and adapted to be engaged by said pairs of movable contacts, barriers extending from the margin of said door opening and preventing access to said stationary contacts from said door opening, and interengaging means between said door and carrier acting lto-prevent the opening ot' said door when either of said pairs of movable contacts are in engagement with said stationary contacts, and to prevent the movement of said carrier to engage either of said pairs of movable contacts with said stationary contacts when the door is opened.

In testimony whereof I have allixed my signature.

GRANVILLE E. PALMER.

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