US2234563A - Circuit controlling device - Google Patents

Description

E. KNEASS 2 Sheets-Sheet 1 CIRCUIT CONTROLLING DEVICE Filed Jan. 18, 1939 Ftc/TZ.

March 11, 1941.

I N VEN TOR.

v ATTORNEY.

March 11,, 1941'. E. KNEASS CIRCUIT CONTRQLLING DEVI CE 2 Sheets-Sheet 2 Filed Jan. 18, 1939 mm QM INVENTOR.

My 62m A TTORNEY.

Patented Mar. 11, 1941 PATENT OFFICE 1 CIRCUIT CONTROILING DEVICE Edwards Kneals, Philadelphia, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation oi New Jersey Application January 18, 1939, Serial No. 251,487

'lClaims.

My invention relates to circuit-controlling devices, and particularly to switches having an operating member for eifecting relative movement of the switch contacts into and out of circuitclosing position and for actuating mechanism which clamps the contacts to each other.

In accordance with my invention, the transition from relative movement of the contacts to actuation of theclamping mechanism is controlled by means which is continuously operatively related to the operating member during the transition; more particularly, the control means comprises cam structure which precludes actuation by the operating member of the clamping mechanism except when the contacts are in circuit-closing position and which precludes relative movement of the contacts unless the clamping pressure has first been to suitable extent relieved; more specifically, the cam structure imposes upon the operating member successive components of motion insuring, in predetermined sequence, clamping or unclamping of the contacts and their relative movement into or out of circuit-closing engagement.

My invention further resides in the features of construction, combination, and arrangement hereinafter described and claimed.

For an understanding of my invention, and for illustration of difierent modifications thereof, reference is to be had to the accompanying drawings, in which:

Fig. 1 is a side elevational view of a switch with its contacts clamped in closed-circuit position;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a top plan view, partly in section, taken on line 3-3 of Fig. 1;

Fig, 4 is a front elevational view of Fig. 1, taken on line 4-4 of Fig. 2, with parts omitted and with the contacts unclamped and in opencircuit position;

Fig. 5 is a side elevational view of a modified form of switch with its contacts clamped in closed-circuit position;

Fig. 6, partly in section, and with parts omitted, shows the switch of Fig. 5 with its contacts unclamped and in open-circuit position;

Fig. 7 is a front elevational view of a multipole switch, one switch partly in section and with parts broken away.

Referring to Figs. 1-4, the movable contact structure of the switch comprises the two movable blades I. I, pivctaliy mounted on opposite sides of the fixed contact or terminal 2 upon the pin or stud 3 which extends through or projects from the terminal 2. The operating member or arm 4 for swinging movable contact structure I, I into and out of engagement with fixed terminal 5 or contact 5 is mounted upon the pin 6 which passes through the blades I, I. As more clearly appears in Figs. 1-3, the pin 6 rotates with the arm 4 when the operating handle I of the arm is swung through an arc having the axis A of the 10 pivot pin 6 as its center. Rotation of the pivot pin with the operating arm may be insured in any desired manner; in the arrangement particularly shown, the operating arm 4 has a noncircular hole which snugly receives a correspond- I ingly shaped central portion 6A of the pivot pin. The outer ends of the pivot. pin 6 threadably engage the clamping bars 8, 8 which are preferably recessed at their lower ends to receive the ends of the pivot pin 3 for the movable contact blades 2 One end of pivot pin 6 is provided with a righthand thread, and the other end of the pivot pin is provided with a left-hand thread; therefore upon rotation of operating arm 4 in one direction about axis A, the clamping plates 8 are moved toward each other, and for reverse rotation of the pin, the plates 8 are moved away from each other. This same result may be accomplished by using a pivot pin threaded only at one end and with a head or shoulder at its other end which bears, either directly or through a suitable bearing, against the outside of the associated clamping plate. However, the illustrated construction is preferred.

The cam 9, which preferably extends from the lower terminal 2, is provided with a continuous slot III for guiding a cam follower II, preferably a roller, pivotally supported by the pin I2 extending between the side members 4a of the switch operating arm. 'I'hecurved sides of the upper section of slot I0, above cusp C, have axis A as their center of curvature; consequently, when the contacts are clamped in their circuitclosing position, Fig. 1, the operating handle I, which may be manually operated, or connected to any suitablemotor device for automatic operation, can be swung only in an are having the axis A as its center. When the movable contacts I, I are in the-closed-circuit position shown in Fig. 1, they therefore cannot be movedfrom that position by the operating handle 1 until the roller II has passed downwardly beyond the cusp C of slot I0. It is thus insured the pressure between the movable blades I, I and the fixed terminals 2, 5 must be suitably reduced before the movable contact structure I, i can be rotated about its pivotal axis B.

For continued downward movement of the operating handle from the position shown in Fig. 1 to the position shown in Fig. 4, the operating arm 4, as above described, first rotates about its axis A until roller |l passes cusp C of the slot or groove l; thereafter, the operating arm 4 and the movable contact structure rotate in a fixed angular relation with respect to each other about the pivotal axis B of the movable contact structure. For that range of its movement within the limits of the lower arcuate section of the groove l3. below cusp C, the operating arm 4 cannot be rotated about its pivotal axis A to effect movement of the clamping members 3 either toward or away from each other, because the sides of this lower section of the cam groove I. have axis B as their center of curvature.

It is thus insured the movable contact structure moves into and out of engagement with the fixed terminal 3 while under the desired clamping pressure which cannot, accidentally or otherwise, be changed by improper manipulation of the operating arm 4. The cam 3 which continuously controls the position of the operating arm 4 throughout its movement of the contact structure and through the transition from such movement to actuation of the clamping bars 3 precludes actuation of the clamping members 3, 3 when the contacts are out of engagement with each other, and permits actuation of the clamping bars to increase or decrease the pressure only when the movable contact structure is in the closed-circuit position of Figs. 1 and 2.

The switch operator to open or close the switch merely moves the handle I from one limiting position to the other without need for attention on his part to rotate arm 4 about its axis A to proper extent before the blades I, l are moved toward or away from closed-circuit position; the cam 9 for continuous movement of arm 4 in either direction imposes upon the movable contact structure and the clamping bars successive components of movement of proper magnitude, and controls the transition from or to contact actuation to or from actuation of the clamping bars.

In the particular construction shown in Figs. 1 to 4, the ends of the cam slot i0 define the limits of movement of the operating arm 4, and the cusp C divides the slot into two distinct sections; the upper arcuate section defines the range of movement within which the operating arm 4 can actuate only the clamping members 3 and the lower arcuate section defines the range of movement within which the operating arm 4 can only effect movement of the contacts I, I toward or away from the fixed terminal 3. Preferably the cusp C is quite sharp, clearly to define the transition between contact clamping and contact movement; to the same end, the width of the slot should closely correspond with the diameter of the roll The transition of control from actuation to clamping of the movable contact structure, imposed, respectively, by the cam surfaces Illa and lb, ispreferably, as shown, immediate, at the region of cusp C; and, in any event, whether the transition period be short or prolonged, the mechanical connection between the operating member 4 and the movable contact structure remains the same throughout both components of control and the intervening transition. Theforegolng is distinguished in practical aspects from the case where the operating member is latched to the movable contact structure during movement thereof to circuit-closing position, which requires tripping of the latch before performance of the clamping operation; the position of the operating member with respect to the movable contact structure at which tripping of the latch occurs is indeterminate and variable as between successive operations of the switch, and so has the practical defect as between successive operations of the switch that both the circuit-closing position of the movable contact and the concurrent clamping pressure vary. Besides, the position of the operating member with respect to the movable contact structure at which relatching occurs in successive operations of the switch is variable and indeterminate, and so has the practical defect that as between successive separation of the contacts the contact pressures during separation may differ to substantial extent.

In the preferred construction herein shown, the relations between the distance between the axes A, B and the lengths of the radii of curve.- ture of the arcuate cam surfaces Illa, lllb, are such the transition from contact actuation to clamping, and vice versa, is immediate, and occurs at a position of the operating arm which is definitely the same for successive operations of the switch.

Referring to Figs. 5 and 6, the switch construction is, in general, similar to that shown in Figs. 1 to 4; the fixed contacts 22 and 23 are mounted on insulators I secured upon base 34; the movable contact structure comprises a pair of blades 2|, 2| mounted upon a pivot 23 extending from or projecting through the lower terminal or contact 22 which, in this modification, is provided with integral extensions 22A for connection to bus bars. Upper contact 23 has extensions 25A for bus bar connections. The clam-ping bars 28, 23, for pressing the movable contact blades 2|, 2| against the lower terminal 22 and the upper terminal 25, are threadably received by the opposite ends of the pivot Pin 26 which is secured to an operating arm 24 connected by links 33 which extend through the switch base 34 to lever 35 on shaft 40 connected by arm 4| and link 38 to any suitable operating means; for example, a manually actuatable handle, or to a solenoid or other motor mechanism.

The cam 23 having the same purpose and function as the cam 3 of Figs. 1 to 4 has one arcuate surface 23a corresponding with the upper section of cam groove Ill, Figs. 1 to 4, and a second arcuate section 29b corresponding with the lower section of cam groove I0, Figs. 1 to 4. When the contacts are in the closed-circuit position of Fig. 5, the operating linkage, including links 33, 36, and arms 24, 35 and 4|, can be actuated only to release or tighten the clamping bars 23; this because arm 24 can then rotate only about axis A, the center of curvature of are 290; the engagement between cam follower 3| and the cam surface 29a prevents any motion of the contact blades 2| about their pivotal axis B.

For continued upward movement of link 36 from the position shown in Fig. 5, the arm 24 is first swung in counter-clockwise direction about its pivot A suitably to reduce the pressure exerted by the clamp bars 23 upon the contacts 2|; as soon as the cam follower 3| passes the cusp C of cam 29, further upward movement of link 36 eifects clockwise rotation of the movable contacts 2| about their pivotal axis B to open the switch.

So long as the cam follower 3| is in engagement with the arcuate surface 29b of cam 29, movement of the operating member 38 can effect only movement of the contacts 2| toward or away' from the fixed terminal 25 and cannot effect actuation of the clamping members 28 either toward or away from each other. The arcuate surface 29b has for its center of curvature the pivotal axis B of the movable contact structure; therefore, for the range of movement of the operating linkage defined by arcuate surface 29b, thearm 24 is maintained in predetermined angular relation to contacts 2|, Fig. 6.

Throughout the entire movement of the operating linkage from one limiting position to the other, the cam follower 3| is continuously operatively related to the cam 29 to preclude actuation of the clamping means so long as and whenever the switch is open, and to prevent movement of the contacts into or out of engagement with each other except at suitable contact pressures.

Preferably the cam 29 is provided with an integral stop or projection 290 for limiting the movement of the contacts 2| away from fixed terminal 25; this stop may, of course, be dispensed with, particularly if a suitable abutment is provided elsewhere in the path of one of the members of the operating linkage.

Cam 29 may be integral with the terminal 22; preferably it is a separate element suitably attached thereto as by the screws 81 which attach it to an extension 38, Fig. 7, projecting downwardly from the central portion of the terminal 22 between the extensions 22A for connection with bus bars. The particular switch shown in Figs. 5 to 7 is an outdoor disconnect switch having a service rating of 6000 amperes at 15,000 volts.

As shown in Fig. 7, several switches of the type shown in Figs. 5, 6, may be mechanically coupled for operation by a single operating member 36 for use in multi-phase power circuits; each switch has its individual cam 29 for determining the limits within which its arm 24 is swung about its pivotal axis A to increase or decrease the contact pressure and for determining the limits within which the contacts 2|, 2| move with arm 24 about pivotal axis B during maintenance of fixed angula'r relation between arm 24 and the movable contacts.

It is to be understood my invention is not limited to the particular constructions illustrated and described as exemplary of my invention, but is coextensive in scope withthe appended claims.

What I claim is:

1. A switch comprising a contact, a pivotally mounted structure including a contact movable to engage said firstnamed contact, means for releasably clamping said contacts to each other, an operating member for said movable contact and for said clamping means pivotally mounted upon said structure, and a cam having arcuate surfaces whose centers of curvature substantially correspond respectively with the pivotal axes of said structure and of said member for sequentially precluding movement of said member about said axes to enforce actuation of said movable contact and said clamping means in predetermined sequence.

2. A switch comprising a contact, a contact movable to engage said first-named contact, means for releasably clamping said contacts to each other, a member operable to actuate said movable contact and said clamping means, and a cam having arcuate surfaces meeting at an abrupt angle sharply to define a limit of a range of movement of said structure within which said operating member cannot actuate said clamping contact members and rotatable in opposite directions to clamp them to or unclamp them from said stationary contact structure, an operating member non-rotatably attached to said threaded member between said contact members, and cam structure disposed in---a plane passing between said contact members substantially parallel to the paths of movement thereof for controlling the position of said operating member relative to said contact members to preclude its rotation of said threaded member except when said contact members are in engagement with said stationary contact structure.

4. A switch comprising a; cam, a fixed contact, switch blades pivotally mounted on opposite sides of said contact with said cam between them, a secondfixed contact having outside faces respectively engageable by the inner faces of said blades, clamping bars engaging the outer faces of said blades to clamp them against said fixed contacts, a threaded member passing through said blades and axially rotatable to effect clamping movement of said bars, and means for eflecting pivotal movement of said blades and axial movement of said threaded member comprising a member extending between said blades from said threaded member and continuously engaged by said cam between said blades.

5. A switch comprising a pair of fixed contacts, switch blades pivotally mounted on opposite sides of one of said contacts for movement effecting engagement of their inner faces with the outer faces of the other of said contacts, a cam supported by one of said fixed contacts between said blades, clamping bars engaging the outer faces of said blades, .a threaded member passing through said blades substantially midway of their length threadably to engage at least one of said bars to effect clamping of said blades upon said contacts, and an operating member extending between said blades from said threaded member continuously to engage said cam sequentially to efiect pivotal movement of said blades and axial rotation of said threaded member.

6. A switch, having a plane of general symmetry, comprising a pair of stationary contact structures, a pair of contact members pivotally mounted upon one of said structures and movable between an open and a closed circuit position, said members embracing said both stationary contact structures when in said closed circuit position, a threaded member movable with said contact members and axially rotatable in opposite directions relative thereto to clamp them or to unclamp them from said stationary contact structure, an operating member non-rotatably attached to said threaded member and located between said contact members and in said plane of symmetry, one of said stationary contact structures comprising cam structure between said contact members and disposed in said plane of symmetry for controlling the position of said operating member relative to said contact members and preventing aforesaid axial rotation of said threaded member except when said contact members are inengagement with said stationary contact structures.

"I. A switch, having a plane of general symmetry, comprising a pair of stationary contact structures, insulating means supporting said structures. a pair of contact members pivotally mounted upon one of said structures and movable between an open and a closed circuit position,

member and located between said contact members and in said plane of symmetry, and controlling means supported by one of said stationary contact structures remote Irom said insulating 1 means and between said contact members and disposed in said plane of symmetry, said control means comprising a cam for controlling the position of said operating member relative to said contact members, and tor preventing aforesaid axial rotation of said threaded member except when said contact members are in engagement with said stationary contact structures.

EDWARDS KNEASS.

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