US1701440A - Switch-latching mechanism - Google Patents

Description

Feb. 5, 1929. 1,701,440

. H. M. CHATTO SWITCH LAIGHING MECHANISM Filed July 1, 1925 Invehtor:

Harry M. Chatto hy H Ls At torm-gy Patented Feb...5 192 9. UNITED. STATES g 4 1,101,440 PATENT OFFICE.

HARRY M. CHATTO, OF SCHENECTADY, NEW YORK, AS SIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SWITCH-LATCHING MECHANISM.

Application filed July 1, 1925. Serial No. 40,942.

My'invention relates to electric switches,

and particularly to the latching mechanism; by means of which the switch is retained 1n,

closed circuit position. An object of my invention is the provision of an improved, switch latching mechanism which is simple in construction, inexpensive of manufacture and which is of such a nature that while it is very sensitive it cannot be jarred out to release the switch.

My invention will be better understood from the following description taken in con nection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Figs. 1, 2 and 3 of the drawing are side elevations of a switch latching mechanism involving my invention and showing the mechanism respectively in latched, partial release, and full release positions; Fig. 4 is a top view of the same; Fig. 5 is a detail on an enlarged scale; and Fig. 6 shows a modification.

On the drawing the base or frame 1 has pivoted to a pair of lugs 2 thereon the weighted lever 3 to one end of which are pivoted the operating links 4. These links, portions only of which are shown, are adapted to connection with switch operating mechanism of common and well known form. Pivoted to two other lugs 6 on the base is the bell crank 7 to one arm of which is pivoted the link 8 which is adapted to operatively connect with the movable contacts of an oil switch. When the mechanism is in the position shown by Fig. 1 the switch is closed andis held in that position by a colla sible connection between lever 3 and bell-c1 k 7 comprising links 10 and 11 forming a toggle.v As shown in Fig. 1, this toggle is slightly underset while a sec ond toggle comprising the lever 3 and the first mentioned toggle is sli htlyoverset, a suitable limiting stop not 5 ownbeing provided for the lever 3. The collapsible connection comprising links 10 and 11 is maintained in extended'condition to hold the switch closed by the releasable member 12 which is pivotally mounted at 13 on link 11. The roller 14 on this member partly overlaps the end of link 10, the parts being so arranged that the roller tends to roll off the end of link 10 and to thus cause member 12 to rotate in a clockwise direction. This rotative movement of member 12 is however opposed by the trigger 15 which is also pivoted to link 11 at 16. This trigger while shown on the draw ing as a bar pivoted in the middle may have any desired shape, the only essehtial requirebearings obviously may be used if desired for v the roller 18 and for the trigger. For returning the trigger to the position shown in Fig. 1 after the mechanism has collapsed and for yieldingly retaining it in that position, I have shown the resetting member 20 which is illustrated ascomprising a weight pivoted at 21't-o member 12. Obviously a spring may be used for this purpose if desired. The

weight has a flat face 22 which by engaging the fiat side of the trigger at points opposite the pivot 16 normally holds the trigger in the position shown by Figs. 1, 3 and 5. A tripping arm 24 carrying a roller 25 is adapted to be actuated by a solenoid 26 responsive to a predetermined circuit condition such for example as an overload. The arm upon being raised by the solenoid strikes the trigger causing it to rotate slightly, thereby releasing the member 12. i

In Fig. 2 the mechanism has been tripped and the connection comprising the links 10 and 11 have collapsed, permitting the initial opening movement of the switch. Lever 3 is now free to rock to the position shown'by Fig. 3 where the switch is full open. The lever 3 upon reaching the position shown by Fig. 3 straightens out the connection 10 and 11 and the member 12 being weighted at 28 resets itself and permits the trigger under the influence of weight 20 to .ride under the roller 18. A downward pull on the links 4 now will effect the closing of the switch.

Because of the fact that the rollen18 bears against the end face of the trigger with a comparatively light pressure and they fact that this face is smooth and concentric with the axis of rotation thereof the device has great sensitiveness. a ,An important feature of my invention is the fact that the trigger which is the final controlling element of the latching mechanism when the switch is closed is balanced,

since all the forces acting upon it pass through its pivotal center. As has already been pointed out the axis of rotation of the trigger passes through its center of gravity, hence it is balanced with respect to the force of gravity. The contact face 17 of the trigger being cylindrical and coaxial with the pivotal center of the trigger, the force'applied by the retaining member 12 is normal to the cylindrical surface and hence passes through the pivotal center of the trigger, also producing a balanced condition.- The third force acting on the trigger is that of the resetting member 20. WVhen the trigger is in reset position the resultant force of this member also passes through the pivotal center of the trigger. By reason of this balanced condition, the trigger is entirely unaffected by any jars to which the mechanism may be subjected and as the trigger controls the entire mechanism the switch will not jar open.

In the modification illustrated by Fi 6 the. releasable member 12' is constructed without the Weighted portion 28, the weight being pivoted to the member 12 in lieu thereof. A lighter construction of the releasable member is therefore possible.

lVhile I have described certain embodiments only of my invention, I do not wish to be limited to the particular forms shown and described as it will be apparent that modifications therein may be made without departing from the scope of my invention as set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In an electric switch, a latching mechanism comprising a releasable member and a trigger pivotally mounted substantially at its center of gravity for retaining the releasable member whereby jars will not cause the release of. the mechanism.

2. In an electric switch, a latching mechanism comprising a releasable member and a pivotally mounted trigger for retaining the releasable member, said trigger having a contact surface which is substantially concentric with its pivotal center and which is adapted to be engaged by the releasable member.

- 3. In an electric switch, a latching mechanism comprising a releasable member and a trigger pivotally mounted substantially at its center of gravity for retaining the releasable member, said trigger having a contact surface engaged by the releasable member which is substantially concentric with its pivotal center. Y

4:. In an electric switch, a latching mechanism comprising a releasable member having a roller mounted thereon, a trigger piv otally mounted on an axis passing through its center of gravity and provided with a face concentric with said axis adapted to be engaged by said roller, means responsive to a predetermined circuit condition for displacing the trigger to release said member, and yielda-ble means for returning the trigger to a position to be engaged by said member.

5. In an electric switch, latching mechanism comprising a collapsible connection, a releasable member having a roller thereon for controlling said connection, a trigger rotatably mounted on a transverse axis passing through its center of gravity. said trigger having an end face concentric with said axis. a weight pivoted to said member and adapted toengage and to normally retain the trigger in a position to have its end face engaged by the releasable member and a member responsive' to a predetermined circuit condition for displacing the trigger.

.In witnesswhereof, I have hereunto set my hand this th day of June, 192

- HARRY M. GHATTO.

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