US2427134A - Safety and locking device for a disconnecting switch - Google Patents

Description

Sept. 9, 1947. '.1, w, GRONBECK 2,427,134

SAFETY AND LOCKING DEVICE FOR A DISCONNECTING SWITCH I I Filed March 6, 1946 INVEN TOR.

Patented Sept. 9, 1947 SAFETY AND LOCKING DEVICE FOR A DISCONNECTING SWITCH John Gronbeck, Edgewood, R. I.

Application March 6, 1946, Serial No. 652,255

1 Claim. 1

This invention relates to disconnecting switches which are commonly used in electric power installations for cutting-out selected circuits or parts of circuits for changes or repairs. If such switches are opened under load, very serious consequences may follow, as they are not designed for such operation.

It is the general object of my invention to make it impossible for an operator to open a disconnecting switch by a single continuous movement, but on the other hand to force him to adopt a step-by-step movement which will prevent the formation of a long and dangerous are if the circuit happens to be under load.

To the attainment of this object, I provide a locking plate mounted on a fixed support and operable to engage and lock a switch-bar on initial opening movement thereof. I also provide a spring'acting to move said locking plate to inoperative position, together with holding means normally overcoming said spring but rendered ineffective by such initial movement.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claim.

A preferred form of the invention is shown in the drawings, in which Fig. 1 is a side elevation of a disconnecting switch embodying my invention;

Fig. 2 is a transverse sectional view, taken along the line 2-2 in Fig. 1;

Figs. 3 and 4 are views similar to Fig. 2 but showing successive operating positions;

Fig. 5 is a partial rear view of the locking plate and associated support, looking in the direction of the arrow 5 in Fig. 1; and

Fig. 6 is a detail sectional View, taken along the line 6--6 in Fig. 2'.

Referring to the drawings, I have shown a disconnecting switch which is in general of an ordinary commercial type and comprises stands or brackets l and II mounted on insulators l2 and having line wires W and W secured thereto.

A switch-bar I is pivoted at IE to the stand or bracket l0, and the stand II is slotted to receive the free or. swinging end of the bar iii. A handle I! is mounted on the bar 15 for yielding outward movement and is provided with a lug l8 normally seated in a notch I!) to hold the switchbar locked in closed position. The parts thus far described are all of usual construction.

The stand I0 is provided with flanges 20 extending to the right in Fig. 1, and a plate or support 22 is mounted in a rearwardly inclined posi- 2 tion on the ends of the flanges 20, as also shown in Fig. 1.

A locking plate 30 is pivoted at 3| on the support 22 and is provided with lower and upper laterally projecting arms 33 and 34.

p The arm 33 has a slight recess 36 (Fig. 6) on its rear face, in which a spring-pressed ball 31 is normally seated. The ball is mounted in a short tube 38 and is pressed outward by a spring 39. When the ball 31 is in the recess 36, the plate 30 is held yieldingly in the normal position shown in Fig. 2 and with the .bar I5 in fully closed position.

The upper arm 34 of the plate 30 has an inverted V-shaped cam notch formed in its under edge and has its outer end cut away or beveled as indicated at 41. A spring (Fig. 5) is mounted at the back of the plate 30 and has its upper end hooked behind a stud 5| in said plate. The lower end is inserted under tension between the rear flange 20 and the rear end of the bolt which forms the pivot IS. The spring 50 tends to swing the plate 30 to the left in Fig. 5 or to the right in Figs. 2, 3 or 4 but is not strong enough to dislodge the ball 31.

Having described the details of construction of my improved safety and locking device, the operation thereof is as follows:

The parts are shown in Figs. 1 and 2 with the switch-bar IS in normal or closed position, and in this position the lower edge of the bar l5 engages the upper edge of the arm 33 and holds the same downward in the position shown in Fig. 2. The spring 39 presses the ball 31 into the recess 36 and thus also holds the plate 30 in the position shown in Fig. 2 until the plate is positively moved therefrom.

When the switch is to be opened, initial upward movement of the bar l5 causes the top edge of the bar to engage an inclined cam surface 40!; forming part of the V-shaped notch 40, and such engagement will swing the plate 30 by cam action to the right in Fig. 2 far enough to clear the recess 36 from the ball 31. The spring 5|] then continues the swinging movement of the plate 3|] until the bar I5 and plate 30 are locked in the position shown in Fig. 3 by the lug 34a on the end of the arm 34. and with the lower edge of the bar IE only slightly clear of the stand II.

If the circuit controlled by the switch is under load, an arc will then be formed but the arc will be of short length and correspondingly harmless. If an arc is formed, the switch-bar will naturally be returned immediately to closed position. If no arc is formed, however, the switch-bar 15 will be bar engages the upper face of the arm 33 and.

swings the plate 30 to the left until it is returned to its original position as shown in Fig. 2.

It will thus appear that I have provided a very simple construction by which a step-by-step opening movement of the switch-bar is required and by which a single full-swing openingmovement is positively prevented. The safety of the operator as well as the equipment is thus insured.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claim, but what I claim is:

A safety and locking device for a disconnecting switch having a switch-bar and a support therefor comprising a locking plate mounted on a fixed pivot on said support and normally operative to engage and lock said switch-bar in partially open position, yielding means to hold said plate in normal operative position, cam means engaged by said bar and effective to cause said locking plate to receive an initial limited angular shift from normal position to an intermediate position within locking range and to simultaneously release said locking plate from said hold- .ing means, and a spring thereafter effective to move said locking plate further in the same direction and fully out of the path of said switchbar when said switch-bar is given a slight return movement to clear said locking plate.

JOHN W. GRONBECK.

REFERENCES CITED UNITED STATES PATENTS Name Date Strai Oct. 31, 1933 Number

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