US3617675A

US3617675A - Heavy-duty switch

Info

Publication number: US3617675A
Application number: US15071A
Authority: US
Inventors: George H Pohm; Harold O Wright; Gary G Siegmund
Original assignee: Lorain Products Corp
Current assignee: Lorain Products Corp
Priority date: 1970-02-27
Filing date: 1970-02-27
Publication date: 1971-11-02
Anticipated expiration: 1988-11-02
Also published as: CA936205A

Abstract

A pressure contact switch having a control member fixed with respect to a movable contact thereby to translate the movable contact from one fixed contact to another fixed contact about a first center when the control member is shifted laterally. A second center is provided about which the control member is rotated at each end of the translating stroke thereby to tighten the movable contact against the respective fixed contact.

Description

United States Patent Inventors George H. Pohm Lorain;

Harold 0. Wright, Lorain; Gary G. Siegmund, Elyria, all of Ohio Feb. 27, 1970 Nov. 2, 1970 Lorain Products Corporation Appl. No. Filed Patented Assignee HEAVY-DUTY SWITCH 2 Claims, 5 Drawing Figs.

U.S. Cl 200/170 A Int. Cl. .H0lh l/50 Field of Search ZOO/11672d References Cited UNITED STATES PATENTS 7/1958 Burt et al. 200/170 RX 11/1960 Kussmaul et a1.. 200/170 A 4/1965 Hales et al. 200/170 R l1/l968 Kussmaul 200/170 A X 7/1969 Kussmaul Primary Examiner-H. 0. Jones Attorney-John Howard Smith ABSTRACT: A pressure contact switch having a control member fixed with respect to a movable contact thereby to translate the movable contact from one fixed contact to another fixed contact about a first center when the control member is shifted laterally. A second center is provided about which the control member is rotated at each end of the translating stroke thereby to tighten the movable contact against the respective fixed contact.

PATENTEU 2 3,617, 67 5 SHEET 1 OF 4 I N VEN TOR.

GEORGE H. POHM HAROLD o. WRIGHT GARY s. SIEGMUND IN VIINTOR.

.GEORGE H. POHM HAROLD o. WRIGHT GARY e. SIEGMUND /i QQNMM PATENIEfluuvz 1971 sum 30F 4 FIG. 3

IN VENTOR. 1

GEORGE H, POHM HAROLD o. WRIGHT GARY s. SIEGMUND HEAVY-DUTY SWITCH BACKGROUND OF THE INVENTION In electrical circuits where switches control theflow of large I electric currents, an important consideration is reducing the voltage drop across the switch contacts. This is because of the adverse affect which this voltagedrop hason the voltage regulation and efficiency of the system in which the switch is used. One desirable method of reducing contact voltage drop is to decrease the resistance of the switch contacts as, for example, by utilizing pressure to force the switch contacts into intimate, face-to-face electrical contact.

Prior to the present invention, this class of switches has utilized springs, cams having complex geometries, or both, or have required a separate tightening mechanism for each fixed contact. The use of springs is undesirablebecause of the tendency of a spring to lose its resiliency after prolonged exposure to the degree of heat often generated in this type of switch. This loss of resiliency can cause the pressure between the switch contacts to lessen, thereby greatly increasing the heat generation at the switch contacts. Since this increased heat generation further weakens the spring, it will be seen that the loss of effectiveness of the switch may become regenerative, resulting in the total failure of the switch or even in a fire. Thus, complexity and temperature considerations have limited the usefulness of heavy-duty switches.

SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to provideimproved bolted contact switches of the single and double throw types.

' It is still another object of the invention to provide an improved switch wherein one or more movable contacts are tightened against one or more respective fixed contacts by single tightening mechanisms attached to respective movable contacts.

It is yet another object of the invention to provide a bolted contact switch including a control member rotatably fixed to a movable contact for laterally displacing or translating said movable contact into a position adjacent to a fixed contact when a follower mechanism attached to the control member moves in one portion of a follower guide, and for tightening or untightening the movable contact in face-to-face relationship against such fixed contact when the follower mechanism moves rotatably with respect to the movable contact in another portion of the follower guide, the follower mechanism being adapted to enter the second portion of the follower guide as the movable contact becomes adjacent .to such fixed contact.

Another object of the invention is to provide a double throw switch of the above character wherein the untightening, displacement or translation and retighteriing of the movable contact is accomplished smoothly by the lateral movement of a single control member along a smooth'arc.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a single-pole double-throw switch embodying the invention,

FIG. 2 is a right side elevation of the switch shown in FIG. 1 and,

FIGS. 3. 4 and 5 are fragmentary fro'nt views of the switch of FIG. 1 in its different positions.

DESCRIPTION OF THE INVENTION Referring to FIG. 1 there is shown a movable contact suitable for completing an electrical path between a common, flexible conductor 1 I and a fixed conductor 12 or a fixed conductor 13. As will be seen more clearly in FIG. 2, movable contact 10 includes two

conductor blades

10a and 10b between which fixed conductor 12 or 13 may be bolted in tight, face-to-face, electrically conducting relationship by the rotation vof bolt 14 in nut 14a. In order to properly orient movable contact 10 fortightening against conductor 12 or 13 the latter conductors are provided with

slots

12a and 13a, respectively. These slots, by receiving bolt 14, stop the arcuate travel of movable contact 10 when the latter is adjacent to fixed conductor 12 or 13. As will be seen presently, both the position of movable contact 10 and the rotation of bolt 14 are controlled in accordance with the position of a control member which here takes the form of a handle 15.

In the following description, the positions referred to are shown in FIG. 1, while the structure connecting handle 15 to movable contact 10 is most clearly shown in FIG. 2. To the end that movable contact 10 may move laterally from fixed conductor 12 to fixed conductor 13 as the end of handle 15 is moved along the circular arc joining position 16a to position 16b on curve 16 of FIG. I, handle 15 is connected to movable contact 10 through an electrically nonconductive coupling 17, a rod 18, and bushings 19 and 20. As will be described more fully later, a follower mechanism connected to handle 15 prevents the latter from rotating with respect to movable contact 10, on movable axis 180 passing through the center of member 18, when handle 15 is being moved between

positions

16a and 16b. This allows handle 15 to displace or translate movable contact 10 between the fixed contacts despite the tendency of handle l5 to rotate about axis 184 when a force is applied thereto. After contact 10 is adjacent fixed contact 12 or 13, however, this follower mechanism releases handle 15 allowing the latter to rotate about axis 180 and thereby tighten bolt 14 through member 18 and

linkages

21, 22 and 23 (see FIG. 1). During the tightening of bolt 14 the end of handle .15 moves along the circular are joining positions 16a and or along the circular are joining positions 161: and 16d depending upon which fixed conductor movable contact 10 is being tightened against.

To the end that the mechanism comprising handle I5, movablecontact l0 and the connections therebetween may be supported with respect to a mounting plate 24, there is provided a member 25 which is rotatably fixed to plate 24 by'a bushing 26. Member 25 is rigidly fixed to conductor 10 through an insulating coupling 27 and a rod 28 and is rotatably fixed to handle 15. Thus, the portion of handle 15 between member 25 and contact 10, rod 18, contact 10, member 25 and rod 28 are free to rotate as a unit on a fixed axis 25a passingthrough the center of member 25 as long as movable contact 10 is not bolted against fixed conductor 12 or 13. It will be understood that plate 24 may be mounted in any suitable equipment by means of

suitable bolt holes

24a, 24b, 24c and 24d.

In order that handle 15 may not rotate about axis 18:: when movable contact 10is translating between conductors 12 and 13 and yet may rotate with respect thereto after movable contact 10 makes contact with conductor 12 or conductor 13, there is provided a follower mechanism which in the present instance includes a follower guide or cam track 29 cut into mounting plate 24, a pair of

rotatable followers

30 and 31 and a follower bracket 32. Because follower bracket 32 is fixed with respect to handle 15 and because bushings 19 and 20 hold handle 15 in the plane of plate 24, bushings 19 and 20 prevent

followers

30 and 31 from leaving cam track 29. Thus, handle 15 can move only in those directions permitted by the movement of

followers

30 and 31 in cam track 29.

When, for example, handle 15 is in the position shown in FIG. 1, it is free to move in one of two directions. First, it may be rotated counterclockwise about axis 18a so that the end of handle 15 travels from position 16a to position 16c. As this occurs,

followers

30 and 31 will roll in circular region 330 at the left end of cam track 29 until follower 31 contacts face 290 which acts as ,a stop. During the counterclockwise rotation of handle 15, rod 18 will rotate to actuate

links

21, 22 and 23 which, in turn, rotate bolt 14 in nut 140. Under these conditions, movable contact 10 will be forced into tight, low-impedance electrical contact with conductor 12, by face-to-face squeezing or pressing action, and the follower mechanism will assume the position shown in FIG. 3. It will be understood that movable contact may be untightened from fixed conductor 12, by rotating handle in a clockwise direction about axis 18a. Thus, the circular

arc joining positions

16a and 16c is associated with the rotation of member 15 about axis 18a and with the tightening and untightening of movable contact 10 with fixed conductor 12.

Second, handle 15 may be rotated clockwise about axis 25a, so that the end of handle 15 travels from position 160 toward position 16b. This causes movable contact 10 to translate between fixed conductors l2 and 13. As handle 15 rotates about axis 25a,

followers

30 and 31 roll in the narrow, central region 33b of cam track 29 until follower 30 contacts point 29d which acts as a stop. The close fit of

followers

30 and 31 in the central region of cam track 29 keeps handle 15 from rotating about axis 18a during the above movement. When follower 30 contacts point 29d, the follower mechanism will assume the position shown in FIG. 4. It will be understood that movable contact 10 may be restored to the position shown in FIG. 1 by rotating handle 15 in a counterclockwise direction about axis 250. Thus, the circular

arc joining positions

16a and 16b is associated with the rotation of member 15 about axis 25a and with the translation of movable contact 10 between fixed conductors l2 and 13.

When, handle 15 is in position 16b, as shown in FIG. 4, it may be rotated clockwise about axis 180 so that the end of handle 15 travels from position 16b to position 16d. As this occurs,

followers

30 and 31 will roll in circular region 330 at the right end of cam track 29 until follower 30 contacts face 29f which acts as a stop. During the rotation of handle 15, rod 18 will rotate to actuate

links

21, 22 and 23 which, in turn, rotate bolt 14 in nut 144. Under these conditions movable contact 10 will be forced tightly against conductor 13 by face-to-face squeezing and the follower mechanism will assume the position shown in FIG. 5. It will be understood that movable contact 10 may be untightened from conductor 13 by rotating handle 15 in a counterclockwise direction about axis 180. Thus, the circular are joining

positions

16b and 16d is associated with the rotation of member 15 about axis 180 and with the tightening and untightening of movable contact 10 with fixed conductor 13.

The ability of handle 15 to travel continuously from are l6a-l6 to are l6a-16c or are l6b-16d results from the relationship between shape of cam track 29 and the locations of

axes

18a and 250. Stop 29a, for example, is so located that as the end of handle 15 is moved in a counterclockwise direction through position 16a, the contact between follower 31 and stop 29a stops the counterclockwise rotation of handle 15 about axis 25a and, at the same time, allows handle 15 to begin a counterclockwise rotation about axis 18a. Similarly, stop 29b is so located that as the end of handle 15 is moved in a clockwise direction through position 16a, the contact between follower 30 and stop 29b stops the clockwise rotation of handle 15 about axis 18a and, at the same time, allows handie 15 to begin a clockwise rotation about axis 250. It will be understood that stops 29d and 29a of 330 serve the purpose as that described above in conjunction with stops 29a and 2912.

In view of the foregoing it will be seen that position 16a is an intermediate position between position 160 where movable contact 10 is bolted tightly against fixed contact 12 and neutral position 16e where movable contact 10 is disconnected from both fixed contacts. Similarly, position 16b is an intermediate position between neutral position 16s and position 16:! where movable contact 10 is bolted tightly against fixed contact 13. Thus, positions 16a and 16b are not normally operating positions.

Assuming that handle 15 is in the position shown in FIG. 3, that is, that flexible conductor 11 is connected to fixed contact 12, and that it is desired to connect the former to fixed contact 13, it is merely necessary to cause handle 15 to laterally traverse curve 16 in a clockwise direction. The motion of the end of handle 15 from position to position 16a unbolts conductor 10 from conductor 12 as handle 15 rotates in a clockwise direction about axis the motion of handle 15 from position 16a to position 16b brings conductor 10 from the position shown in FIG. 1 to the position shown in FIG. 4 as handle 15 rotates in a clockwise direction about axis 25a; the motion of handle 15 from position 16b to position 16d, as shown in FIG. 5, bolts conductor 10 to conductor 13 as handle 15 rotates in a clockwise direction about axis 18a. Similarly, the motion of handle 15 along curve 16 in a counterclockwise direction from position 16d to position 16c reverses the above sequence. Thus, motion of a single control member in a single direction along a smooth, continuous curve unbolts a movable contact from one conductor, translates the movable contact into contact with another conductor and securely bolts the latter together.

When it is desirable to provide a neutral or off position for the switch of the invention, this may be accomplished by providing a latch mechanism of the type shown at 34 in FIG. 1. This latch normally hangs by its own weight from a pivot 35 but may be lifted by raising a pin 36 connected thereto through a slot 37. It will be seen that as handle 15 is moved from position 16a toward position 16b it will raise latch 34. Thereafter, if handle 15 is moved further to the right, latch 34 will capture the latter in groove 38 thereby locking handle 15 in position 162. In addition, this latching mechanism prevents handle 15 from overshooting the ct? position when the switch is opened.

It will be understood that, if only one fixed contact is required, that is, if a switch is to be used as a single-pole singlethrow switch, this may be accomplished by leaving out one of the fixed conductors and one of the rotation guides. It will be further understood that if more than one movable contact is required, it may be provided by furnishing other conductor assemblies such as conductor assembly 10 and by connecting these additional assemblies to

members

18 and 28 in the manner shown with reference to conductor assembly 10 in FIG. 2.

From the foregoing, it will be seen that a bolted contact switch constructed in accordance with the invention is adapted to accomplish the desired movement and tightening of one or more movable contacts as a result of the movement of a single control member in a single direction along a smooth arc. In other words, considering a single, smooth stroke of the single control member, in changing from one fixed conductor to another, the operator moves the movable contact from bolted condition at one fixed contact to unbolted condition, translates the movable contact to the other fixed contact and, in a continuous motion bolts the movable contact to the other fixed contact. This eliminates the possibility of error which exists in equipment where an operator must choose which of a series of mechanical operations will accomplish the desired switching activity.

It will be understood that the embodiment shown herein is for explanatory purposes only and may be changed and modified without departing from the spirit and scope of the appended claims.

What is claimed is:

1. In a pressure contact switch, in combination, at least one fixed contact means, guide means having a translation section and at least one interconnecting rotation section, a movable contact having a center of rotation fixed with respect to said guide means, handle means pivotally mounted on said movable contact, follower means fixedly secured to said handle means on the pivotal axis thereof, said follower means being adapted to traverse said translation section of said guide means in nonrotation relationship whereby movement of said handle means moves said movable contact about its center of rotation toward and away from said fixed contact means and being adapted to rotate in a rotation section of said guide means whereby said handle means moves pivotally with respect to said movable contact, pressure means for applying pressure between said movable contact and fixed contact means, linkage means connecting said handle means and said pressure means whereby said pressure means applies and removes pressure between said movable contact and fixed contact means upon relative pivotal movement between said handle means and said movable contact when said follower means is aligned with a rotation section and said movable contact overlaps a fixed contact means.

2. In a pressure contact switch, in combination, at least one fixed contact means, plate means disposed in fixed relationship to said fixed contact means, movable contact means having a portion thereof adapted to engage and disengage said fixed contact means and having acenter of rotation in fixed relationship to said plate means, operating handle means pivotally connected on said movable contact means, a cam track on said plate means, said cam track including an intermediate, elongate section and at least one substantially circular terminal section, follower means fixedly connected to said operating handle means on the pivotal axis thereof with said movable contact means, said follower means being configurated to ride nonrotatably in said elongate section of said cam track whereby movement of said operating handle means moves said movable contact means about the center of rotation of said movable contact means toward and away from said fixed contact means and also configurated to ride rotatably in said substantially circular section of said cam track whereby said operating handle means and said follower means rotates relative to said movable contact means, pressure-applying means for pressing said fixed and said movable contact means together, linkage means operatively connecting said pressure-applying means and said operating handle means for tightening and loosening said pressure-applying means upon rotation of said operating handle means relative to said movable contact means when said follower means is engaged in said substantially circular section of said cam track.

t I l t UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 I 617 ,675 Dated November 2 1971 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 47, change "l6a-l6" to --16a-16b--.

Signed and scaled this 18th day of April 1972.

Attest:

EDLMRD 1-I.FLETCIa.Eii,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents RM PO-HJSO {10-69) USCOMM-DC 50376-969 U S GOVERNMENT PRINTING OFFICE 9959 03$6 336

Claims

2. In a pressure contact switch, in combination, at least one fixed contact means, plate means disposed in fixed relationship to said fixed contact means, movable contact means having a portion thereof adapted to engage and disengage said fixed contact means and having a center of rotation in fixed relationship to said plate means, operating handle means pivotally connected on said movable contact means, a cam track on said plate means, said cam track including an intermediate, elongate section and at least one substantially circular terminal section, follower means fixedly connected to said operating handle means on the pivotal axis thereof with said movable contact means, said follower means being configurated to ride nonrotatably in said elongate section of said cam track whereby movement of said operating handle means moves said movable contact means about the center of rotation of said movable contact means toward and away from said fixed contact means and also configurated to ride rotatably in said substantially circular section of said cam track whereby said operating handle means and said follower means rotates relative to said movable contact means, pressure-applying means for pressing said fixed and said movable contact means together, linkage means operatively connecting said pressure-applying means and said operating handle means for tightening and loosening said pressure-applying means upon rotation of said operating handle means relative to said movable contact means when said follower means is engaged in said substantially circular section of said cam track.