US2719890A - Operating linkage for electromagnetically operated switches - Google Patents

Description

Oct. 4, 1955 H. E. SCHLEICHER 2,719,590

OPERATING LINKAGE FOR ELECTROMAGNETICALLY OPERATED SWITCHES Filed May 6, 1953 2 Sheets-Sheet l WITCHES Oct. 1955 H. E. SCHLEICHER OPERATING LINKAGE FOR ELECTROMAGNETICALLY OPERATED S Filed May 6 1953 2 Sheets-Sheet 2 fiU/e'l 1%01. jicwofdli'cfdeicrcer Q/EL ML United States Patent OPERATING LINKAGE FOR ELECTROMAGNETI- CALLY OPERATED SWITCHES Harold E. Schleicher, West Hartford, Conn., assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application May 6, 1953, Serial No. 353,364

11 Claims. (Cl. 200-87) This invention relates to operating linkages for electromagnetically operated switches and particularly those electromagnetically operated switches in which the electromagnet armature moves in a plane parallel to and between a backplate and an insulating base spaced from the backplate, the switch contacts being located on top of the base and operated through it. Although the invention relates to and is particularly useful in connection with that type of switch it is not limited to that use but may be used elsewhere.

Electromagnetically operated switches are commonly provided of different sizes to take care of diflerent current and voltage requirements. For devices designed to handle heavy currents and higher voltages the parts are necessarily larger because, in order to handle a heavy current, heavy contacts and terminals are required and hence larger supporting mechanism (which itself is heavier) must be operated. Hence the electromagnet also must be larger and more massive. Thus different conditions and circumstances require change in the form and operation of the various types of electromagnetic switches.

The present invention is particularly adaptable for starting switches and like uses of sizes up to about 50 H. P. at voltages of 550 volts or less (polyphase).

in order that the switch may have long use it is desirable that the movable contacts have a wiping action as they engage and disengage the fixed contacts. It is also desirable that the contacts move substantially perpendicularly towards and from the fixed contacts due to the fact that the movable contacts are located above the switch base and on the opposite side thereof from the electromagnet and its operating mechanism.

Therefore it is an object of the invention to provide improved operating means for an electromagnetically operated switch or controller in which movable bridging contacts are mounted upon one side of an insulating base and may be moved toward the base into engagement with fixed contacts with a wiping action by mechanism mounted upon the other side of the base.

Another object is to provide operating mechanism for the switches of the above mentioned sort in which the operating parts may be economically manufactured and assembled and will be reliable during long and continuous operation.

Another object is to provide operating mechanism for switches of the above sort having provision to prevent twisting and turning of the mechanism by the magnet as it actuates the mechanism.

Other objects and advantages will become apparent as the invention is described in connection with the accompanying drawing.

in the drawing Figure 1 is a perspective view partly broken away of a switch embodying the invention;

Figure 2 is a longitudinal vertical sectional view taken along lines 2-2 of Figure 4 with the location of the electromagnet indicated in dotted outline.

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Figure 3 is a fragmentary perspective view of certain parts of the operating linkage.

Figure 4 is a longitudinal vertical section view taken along line 44 of Figure 5;

Figure 5 is an end elevation view of the invention.

Referring to the drawings a base 10 of molded or other suitable insulating material is supported from a sheet metal backplate by stamped sheet metal sideplates 17 and 18 located at opposite sides of the device. These sideplates have flanges at their tops and bottoms such as 17a, 18a, 17b and 18b, respectively. The insulating base 10 rests upon and is secured at its end edges to the flanges 17a and 1811 while the bottom flanges 17b and 18b rest upon and are secured to the backplate. On the top surface of the base 10 sets of fixed contacts 12a and 12b are mounted in parallel spaced relation and are secured at opposite edges to said base. There may be as many sets of fixed contacts as required for the particular usage to which the switch is to be put. The fixed contacts are adapted to be engaged and disengaged by a bridging contact bar 14 mounted upon an insulating contact carrier 16. The contact carrier may be molded from insulating material with a transverse portion running from one end towards the other beneath the base and mounted so as to be movable toward and from the base. Contact supporting posts 16a may extend up at spaced points along the contact carrier and extend through apertures in the base so as to permit mounting of the bridging contacts 14 on the upper and outwardly extending ends of said posts. The contact carrier may be mounted on a supporting yoke of substantially inverted U-shape (designated generally by numeral 30) having a transverse portion 30! upon which the contact carrier 16 is mounted. Vertical legs 39a and 3012 extend parallel to one another down from the transverse portion of the yoke adjacent but spaced from the opposite sideplates of the device.

The electromagnet and the actuating means connecting it with the movable contact carrier are located between the base and the backplate so as to be isolated from the switch contacts and terminals. The electromagnetic operating means may consist of a conventional C-shaped field piece 29 made of laminated magnetic material in the center opening of which is located a conventional solenoid coil 22. Within the coil and movable in and out thereof is a T-shaped armature 24 also made of laminated magnetic material. The field piece is located in parallel relation to the insulating base and backplate so that the armature will move in a plane parallel to the base and backplate.

In order to transmit the force of the armature and, also, to translate its motion from parallel to the base into motion of the contacts to and from the base, a drive rod 32 is provided extending transversely between the sideplates 17 and 18 parallel to the planes of the base and the backplate. Its ends are guided in elongated slots such as 18s punched in the sideplates 17 and 18. These slots are identically placed and extend parallel to the base and backplate and hence the drive rod is guided in a plane parallel to the base and plate.

To transmit the force of the armature to the drive rod a driving member 34 stamped from sheet metal and loosely and pivotally secured to the armature is looped around the rod and connected to the armature. Near the opposite ends of the drive rod 32 similar stamped sheet metal driving links or bars 36a, 3612 are mounted. To pivotally support these links on the drive rod each link has a hollow cylindrical bushing 3% mounted on its end. One end of each bushing is formed with a reduced neck 38n providing a shoulder which abuts the outside of the link as the reduced neck is inserted in a hole provided therefor in the end of the link. On the reduced neck 3811 is a collar 39, the end of the neck being staked over against the end of the collar thus firmly and securely afiixing the bushing on the driving link and providing a bearing for the pivotal mounting of the link upon the drive rod.

At their other ends the links 36a and 3611 are each respectively pivotally connected to identical triangularly shaped bell-crank levers ib-a, MI), by a pin 41a, 41b. These bell-crank levers are each respectively pivotally mounted upon coaxial fixed studs 42a, 42b secured to and extending inwardly from the side plates 17 and 18 above the pivotal connection or" the driving links to said bellcrank levers. A reduced neck may be formed on the inner end of each of the mounting studs 42a, 42b, the ends of the necks being turned over to hold the bell-crank levers on the studs.

From the foregoing it will be observed that the motion of the armature is transmitted through the drive rod 32 and the driving links 36 to the bell-crank levers 40a and 40b and that the bell-crank will pivot about the fixed studs. In order to transmit the motion of the bell-cranks to the contacts the bell-cranks are pivotally connected by pins 44a, 44b to the side arms 39a and 3012 respectively of the contact-carrier supporting yoke. This pivotal connection is made intermediate the lower ends of the side arms 30a and 30b and the transverse connecting portion 30L In order to guide the movement of the lower ends of the arms 30a and 3%, a pivotally mounted guide member is provided, designated generally by numeral 48. This member may conveniently be stamped from sheet metal into U-shape having parallel identical side arms 43a, 48b, which are connected intermediate their ends by a transverse bar 482. The arms 48a and 48b extend par allel to the side plates 17 and 18 inwardly of the device. Their inner ends are connected pivotally to the lower end of the side arms 391i and 30b of the contact-carrier sup porting yoke by the pivot pins 46a, 46b and their other ends are pivotally mounted upon identical fixed coaxial pins 49a, 49b mounted in the side plates 17 and 18 beneath the drive rod 32.

In order to constantly urge the mechanism into the position which the parts occupy as in Figure 3, a pair of coiled tension springs Sila, 50b may be provided inside of the side plates and between them and the linkage mechanism just described. One end of each of the springs is connected to fixed pivot pins @911, 491; on the connecting member of guide link 48. The other ends of these springs are connected with heads 37]), 37a inturned at right angles on the ends of the driving links 36a, 3612.

From the foregoing the operation of the invention may r be understood. As the armature 24 is attracted when the solenoid is energized the drive bars 36a, 36b will be moved inward. Their outer ends will slide inwardly parallel to the side plate guided by slots 17s, 18s while their inner ends cause the bell-crank levers 40a, 40b to pivot about the coaxial fixed pivots 42a, 42b, causing the coaxial pivotal connections 44a, 4431 between the bell-crank levers and the contact carrying yoke 30 to move down, i. e.. toward the hackplate. That downward movement is guided by the coaxial pivotal connections 46a, 46b of the contact carrying yoke arms at their bottom ends with the side arms of the guide member 48 as the latter pivots about the fixed pivots 49a, 4%.

Since the bell-crank levers 4%, 40b swing about an are smaller and in an opposite direction to the arc of the guide member 48, the switch contact-carrier moves with an S motion towards closed position thus producing a Wiping action as the movable contacts engage the fixed contacts. The opposite wiping action occurs when the contacts separate. This tends to keep the contacts clean and bright, giving better and lower resistance contacting and prolonging the life of the switch.

Many modifications within the scope of the invention will occur to those skilled in the art. Therefore the invention is not limited to the specific form and configuration of the parts illustrated and described.

What I claim is:

1. In combination, an insulating base, fixed contact means mounted thereon, bridging contact means movable to engage and disengage said fixed contacts with a wiping action, and mechanism for transmitting a contact moving force to said bridging contact means comprising a contact supporting yoke, bell-crank lever means pivotally connected thereto, a fixed pivot for said bell-crank lever means, driving means pivotally connected to said bell-crank lever means, means to move said driving member substantially longitudinally causing movement of said bridging contact means toward and from said base, movable guide means pivotally connected to said yoke, and a fixed pivotal mounting for said guide means, said guide means and said bell-crank lever means cooperating with said yoke to provide to-and-fro wiping engagement of the movable contacts over the fixed contacts.

2. The combination claimed in claim 1 having a rigid one-piece yoke to prevent twisting of the bridging contact means relative to the fixed contact means.

3. The combination claimed in claim 2 wherein the guide means comprises a rigid one-piece member which connects with the yoke on opposite sides, preventing twist ing of the operating mechanism.

4. The combination claimed in claim 1 wherein the guide means comprises a rigid one-piece member which connects with the yoke on opposite sides, preventing twisting of the operating mechanism.

5. In combination, an insulating base, fixed contact means mounted thereon, bridging contact means movable to engage and disengage said fixed contacts with a wiping action, and mechanism for transmitting a contact moving force to said bridging contact means comprising contact supporting means, lever means pivotally connected to said contact supporting means, a fixed pivot about which said lever means turns when an operating force is applied to said lever means, and guide means pivotally connected to said contact supporting means at a point spaced farther from the contact means than the pivotal connection of said lever means and contact supporting means, and a fixed pivotal mounting for said guide means located to cause pivoting of said guide means in the opposite direction to said lever means and to cause to-andfro wiping movement of the movable contacts over the fixed contacts.

6. In combination, an insulating base, fixed contact means mounted thereon, bridging contact means movable to engage and disengage said fixed contacts with a wiping action, and mechanism for transmitting a contact moving force to said bridging contact means comprising contact supporting means, a plurality of lever means pivotally connected to said contact supporting means at spaced points along the latter, fixed pivotal mountings for said lever means located at spaced points to cause said bridging contact means to have a sidewise component of motion in one direction at the outset of movement toward said fixed contact means, and to have a sidewise component of motion in the opposite direction at the end of contact engaging movement, whereby a wiping action of the contact means is provided.

7. In an electric switch, the combination claimed in claim 6 wherein one lever means is in the form of a bellcrank, and operating means connected thereto movable in a direction substantially perpendicular to the movement of said contact supporting means.

8. In an electric switch, the combination claimed in claim 7 wherein the bridging contact means are mounted on an insulating support carried by the contact supporting means, said support having portions extending through said base on which said bridging contact means are mounted, said mechanism for moving said bridging contact means being on the opposite side of the base.

9. In an electric switch, the combination claimed in claim 6 wherein one lever means is in the form of a bellcrank, and operating means connected thereto movable in a direction substantially perpendicular to the movement of said contact supporting means, said operating means having a spring anchor formed thereon, and spring means connected to said anchor at one end and to a fixed part at the other end to bias the parts toward one position.

10. In an electric switch, the combination claimed in claim 6 wherein one lever means is in the form of a bellcrank, and operating means connected thereto movable in a direction substantially perpendicular to the movement of said contact supporting means, means guiding one end of said operating means for movement in a straight line, and a rectilinearly moving electromagnet armature connected to said guide means.

11. In combination, an insulating base, fixed contact means mounted thereon, bridging contact means movable to engage and disengage said fixed contacts with a wiping action, and mechanism for transmitting a contact mov- 20 ing force to said bridging contact means comprising contact supporting means, lever means pivotally connected to said contact supporting means, a fixed pivot about which said lever means turns when an operating force is applied to said lever means, and guide means pivotally connected to said contact supporting means, the pivotal connections of said lever means and guide means to said supporting means being spaced apart with one farther than the other from said contact means, said guide means and said lever means cooperating with said supporting means to provide to-and-fro wiping engagement of the movable contacts over the fixed contacts.

References Cited in the file of this patent UNITED STATES PATENTS 1,714,085 Getchell May 21, 1929 1,783,421 Getchell Dec. 2, 1930 1,816,429 Getchell July 28, 1931 2,283,795 Dahl May 19, 1942

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