US2040772A - Make and break switching device - Google Patents

Description

May 12, 936. E E. JOHNSON MAKE AND BREAK SWITCHING DEVICE Filed Dec. 14, 1934 Patented May 12, 1936 UNITED STATES PATENT OFFICE Edward E. Johnson, St. Paul, Minn., assignor to Edward E. Johnson, Incorporated, St. Paul,

Minn.

Application December 14, 1934, Serial No. 757,579

' 9 Claims.

My invention relates to a make-and-break switching device for controlling an intermittent electric current, as, for example, an intermittent flow of welding current employed in spot welding. It is an object of my invention to provide a rotary contactor adapted to be rotated at a uniform rate which will effect contacts to close an electric circuit over a portion of its cycle of rotation and will be out of contact over the remain- 1 ing portion of said cycle of rotation, thus making and breaking the circuit in a timed relation.

It is a further object of my invention to provide such a make-and-break device which can be operated at very high speed and which will at all 15 times be accurate and uniformly timed in 0peration no matter how great the speed.

It is a further object of my invention to provide synchronously-operated pairs of such rotating make and break members with means for 20 adjusting the members of the pair relatively'so as to lengthen or shorten the period of closed circuit for each cycle of rotation as may be desired.

It is a further object of my invention to provide :25 means for throwing out the contact members with which the aforesaid contactor cooperates so as to throw out the operation of the circuit makeand-break switch as desired.

The full objects and advantages of my inven- 30 tion will appear in connection with the detailed description thereof and the novel features are particularly pointed out in the claims.

In the drawing, illustrating an application of my invention in one. form,--

Fig. 1 is a front plan view of my switching device in the thrown-out position with a part broken away and in section. Fig. 2 is a partial front view of the parts shown in Fig. 1 with the contact members in thrown-in position. Fig. 3 is a side 40 elevational view of the switching mechanism.

Fig. 4 is a view similar to Fig. 3 on line 44 of Fig. 1. Fig. 5 is a section through the contact brush.

A base ID has thereon a pair of standards II 45 and I2 secured by bolts [3 and a flange plate l4 to the base at one side thereof. A similar pair of standards is similarly secured by bolts I6 and flange plate I! at the other side of base In.

Journaled in the respective standards ll, 15 and 50 I2, I 5, in the same horizontal plane and in parallel relation, are two shafts l8 and l 9 having thereon equal meshing gears and 2|, preferably of non-conducting material. Shaft I9 is extended as indicated at 22 to connect with suitable driv- 55 ing mechanism (not shown) by which the two shafts l8 and 19 are rotated at a desired speed, the driving mechanism being provided with wellknown change-speed mechanism, not shown.

Centrally disposed on shafts l8 and H! are split carrier blocks 23 and 24 having thereon radiallyextended arms 25 and 26. Carrier block 24 is secured upon a squared portion 21 of shaft I9 and is insulated from said shaft as indicated at '28 in Fig. 3. The carrier block 24 embraces this squared portion of insulation and is securely held by means of a screw-bolt 29 which extends through the cleft portion 30 of brush carrier 24. The carrier block 23 embraces an enlarged circular portion 3| of shaft [8 and is insulated therefrom as indicated at 32 in a manner similar to that of carrier block 24. The carrier block 23 is held in any desired adjusted position on the portion 3! by means of the set-bolt 33 and the cleft portion 34. The adjustment of the arm 25 in any desired angular position is to increase or decrease the time of closing the. circuit and resulting duration of electric current, as may be desired.

Journaled in the standards ll, l2 on one side and the standards I 5 on the other side are a pair of rockshafts 35, 36, which have secured thereto arms 31, 38 adapted to be operated, up as in Fig. 2 or down as in Fig. 1, by an operating link 39. This link may be connected to any desired operator, as a manually-controlled lever or an electrically-operated solenoid (neither being shown) of usual construction, to throw in and throw out the switching mechanism as desired. Upon the shaft 35 is mounted two pairs of spring arms 4U, 41 and 42, 43, and on shaft 36 are two 'correspondingly-positioned pairs of spring arms 44, 45 and 46, 41, as best shown in Fig. 4. These sets of arms 40, 4| and 42, 43 on one side and 44, 45 and 46, 41 on the other side depend from the rockshafts 35 and 36 and are moved simultaneously inwardly and outwardly by rocking of said rockshafts. Each of the spring arms above enumerated carries a pad 48 of insulating material, as shown in Figs. 1 and 2, and these insulating pads may be at suitable times engaged by the ends of plungers 49 and 50.

The plungers 49 and 50, as clearly shown in Fig. 1, are mounted to be transversely movable in long brackets 5| and 52, respectively, which are formed of insulating material and secured to the base I0 bymeans of screws 53. The plungers 49, in pairs, have fast thereon arcuate contact pieces 54 and 55, while the plungers 50 have in pairs fast thereon arcuate contact pieces 56 and 51. The plungers are held in the position of Fig. 1,

with collars 58 engaging the inner walls of brackets 5| and 52, by means of compression springs 59 in cylindrical pockets 60, as clearly shown in Fig. 1. A cylindrical collar 61 seats in the socket 66 and is provided with a shoulder 13. A check nut 66 on the threaded end 69 of plunger 49 is adapted to position the shoulder 13 so as to limit the inward movement of the plunger and the attached arcuate contact pieces, to hold them in the right position to be engaged by the brush mechanism hereinafter described.

Mounted for endwise sliding movement in the outer ends of arms 25 and 26 is a brush 1!) formed of carbon or other good current-carrying material, which has on its ends contact surfaces 6| and 62. The brush 16 is provided with a longitudinal slot 1| through which extends a screw pin 12 as shown in Fig. 5. Also the fit of the brush in the holes in the arms 25 and 26 is loose enough to permit longitudinal movement in either direction of the brush 10 on the pin 12. The length of the brush 16 is such that the faces 6| and 62 at its extremities are adapted to engage the arcuate contact pieces 54 and 56 or 55 and 51 when in their inward or active position as in Fig. 2. This engagement will be such as to tend to push the contact pieces of a pair, as 54 and 56, away from one another slightly against the spring pressure of the arms 40, 4|, 44, 45 or 42, 43, 46, 41 and the compression springs 59. The longitudinal sliding action of brush 10 adjusts the position of brush surfaces 6| and 62 to equalize the pressure thereon from the respective pairs of contact pieces 54, 56 or 55, 51. This insures a perfect wiping contact of the brush surfaces GI and 62 with each of the arcuate contact pieces whereby a perfect electrical conducting contact from these pieces across the brush is assured.

In the position of Fig. 1 contact faces 6| and 62 of the respective brushes 1|] on the arms 25 and 26 will not engage the faces of arcuate contact sectors 54, 56 of one pair of plungers or of arcuate contact sectors 55, 51 of the other pair. In this position, therefore, determined by the position of the link 39 and connected parts, and by the operation of springs 59, there will be no closing of the circuit and the switch, notwithstanding that the arms 25 and 26 are being rotated, will be inoperative. When, however, the shafts 35 and 36 are rocked by pulling up on the shifter link 39, the sets of spring arms 40, 4| and 42, 43 on one side and 44, 45 and 46, 41 on the other side will simultaneously thrust the plungers 49 and 50 toward each other from their position in Fig. 1, against the opposing action of compression springs 59, to their position in Fig. 2. This is the operative position of the switch, wherein, as heretofore pointed out, the arcuate contact sectors 54, 56 and 55, 51 are yieldingly held to have the contact surfaces 6| and 62 of brush 10 engage them with a. wiping contact at each revolution of the shafts l8 and IS. The inward position of the contact sectors in the path of brush 10 is limited by shouldered collars 13 on the plungers 49, but the contact sectors can be pushed away from each other as much as needed against the pressure of springs 59 and that of the spring arms, with longitudinal adjustment of the brush 10 to efiect equalized pressure from each of said arcuate contact sectors, thus insuring a good spring-pressed circuit-closing contact between contact sectors 54 and 56 of one pair and 55, 51 of the other pair and the faces 6|, 62 of brushes 10.

Line wires 63 and 66 are connected to the contact sectors 54 and 55 respectively and other line wires 64 and 65 are connected to contact sectors 56 and 51. When, therefore, the contact surfaces 6| and 62 of brush 10 on arms 25 and 26 are between the sets of contact sectors 54, 56 and 55, 51, respectively, the circuit will be completed through the brush 10 from Wires 63, 66 to wires 64, 65. The wires 63, 66 come from a common line and the wires 64, 65 lead to a common line so the contacts above defined will close the circuit as long as the faces 6|, 62 of brush 16 are in contact with either of the sets of contact sectors 54, 56 or 55, 51. Since these arcuate contact sectors are mounted on insulating brackets 5| and 52 and are further insulated from the sets of spring arms 46, 4| and 42, 43 on one side and 44, 45 and 46, 41 on the other side by pads 43, and the brush carriers 23 and 24 are insulated from their driving shafts, the line current is confined to a circuit passing from wires 63, 66 through brush 16 to wires 64, 65.

The arms 25 and 26 will move in opposite directions across the contact sectors. When they are in the dotted-line position shown in Fig. 3 each will have moved one-half the length of its set of contact sectors and have one-half of their length yet to move, so that the period of circuit-closing will have the relation of the time it takes either or both contact discs to travel the length of the contact sectors. In the position of Fig. 4 the arm 26 and brush 10 with its contact surfaces 6|, 62 has traveled substantially the length of the con tact sectors 55, 51 in contact or circuit-closing relation thereto, while the arm 25 and its brush 10 with its contact surfaces 6|, 62 have substantially the whole length of contact sectors 54, 56 to travel in contacting or circuit-closing engagement. Hence, in this relative position of the arms 25, 26 the closing of the circuit will be for a period substantially equal to the time it will require first one and then the other of the brushes 16 to pass in contacting engagement the sets of contact sectors 54, 56 and 55, 51, respectively, or substantially a closing of the circuit of double the duration of that eifected when the arms are in the position of Fig. 3. By adjusting the arm 25 as indicated in Fig. 4, the length of duration would be substantially one and one-half times that when the arms are in the position of Fig. 3. This adjustment, therefore, makes possible an adjustably variable duration of circuitclosing from the minimum possible of once the time of contact with a set of arcuate contact sectors up to twice that time and for any intervening periods.

The advantages of the make-and-break switching device above described reside in the fact that the closing and breaking of the circuit is effected with certainty and very little sparking, and that it can be effected so certainly when the makeand-break is very rapid, say up to from five hundred to a thousand times per minute; that the duration of the period of current flow is nicely adjustedfrom a minimum to a maximum of double the part of the cycle of revolution of the shaft represented by the length of one set of contact sectors; and, finally, because the structure even when subjected to the heavy duty of the extreme- 1y rapid make-and-break above noted, will perform this function without injury or undue wear, so it is durable and capable of long, eifective use.

I claim:

1. A make-and-break switch for electric circuits, comprising contact members, spring means holding said control members spaced apart to break said circuit, a second contact member adapted to engage the first-named contact members simultaneously and spread them against the forces of said spring means to close the circuit, and means for moving the second contact member into and out of such engagement at a regular predetermined rate.

2. A make-and-break switch for electric circuits, comprising contact members held in spaced parallel relation to break said circuit, a shaft an arm connected with the shaft, a single brush member mounted for transverse movements on said arm, its opposite faces adapted to engage the first-named contact members simultaneously to close the circuit, and means for rotating the shaft at a regular predetermined rate.

3. A make-and-break switch for electric circuits, comprising contact members held spaced apart to break said circuit, a second contact member adapted to engage the first-named contact members simultaneously to close the circuit, means for moving the second contact member into and out of such engagement at a regular predetermined rate, a link and connections therewith for separating said contact members so that the rotating member cannot engage them and the make-and-break switch is thereby thrown out of operation.

4. A make-and-break switch for electric circuits comprising contact members having faces held in spaced parallel relation to break said circuit, means for automatically filling the gap between said contact members at definitely-timed intervals and for definite periods of time to close the electric circuit during said timed periods only,

, and means for extending or diminishing the effectively-engaging portions of said faces to vary the lengths of said closed periods.

5. A make-and-break switch for electric circuits comprising two pairs of arcuate contact sectors held in spaced parallel relation in said circuit and breaking the same through said spacing, a shaft in spaced relation to each pair of sectors, and a contact member carried by each shaft in position to be brought to fill the gap between its adjacent first-named contact members over definitely-timed intervals during each cycle of rotation of the shafts, and means to rotate the shafts.

6. A make-and-break switch for electric circuits comprising two pairs of arcuate contact sectors held in spaced parallel relation in said circuit and breaking the same through said spacing, a shaft in spaced relation to each pair of sectors, a contact member carried by each shaft in position to be brought to fill the gap between its adjacent first-named contact members over definitely-timed intervals during each cycle of rotation of the shafts, means to rotate the shafts, and means to adjust the relation of contacts for said last-named rotated contact members to lengthen or shorten the period of contact and closing of the circuit during each cycle of rotation of the two shafts.

7. A make-and-break switch for electric circuits comprising alined plungers each having a contact member at its adjacent end, spring means holding said contact members with their faces spaced definite distances to break the electric circuit, and conducting means brought between and engaging and spreading said faces at definitely-timed intervals and for definite periods of time to close the electric circuit during said timedperiods only.

8. A make-and-break switch for electric circuits comprising alined plungers each having a contact member at its adjacent end, spring means holding said contact members with their faces spaced definite distances to break the electric circuit, a shaft, a conducting contact member carried by the shaft in position to be brought between and engage and spread said first-named contact members over definitely-timed intervals during each cycle of rotation of the shaft, and means to rotate the shaft.

9. A make-and-break switch for electric circuits comprising alined plungers carrying contact members at their adjacent ends, spring means holding said plungers and contact members with their faces spaced definite distances to break the electric circuit, conducting means brought between and engaging and spreading apart said faces at definitely-timed intervals and for definite periods of time to close the electric circuit during said timed-periods only, and means to move the plungers in opposite directions to further separate said contact faces out of position to be engaged by said last-named conducting means.

EDWARD E. JOHNSON.

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