US1267222A - Safety-stop for switches. - Google Patents

Description

C. H. HILL.

SAFETY STOP FOR SWITCHES.

APPLICATION FILED NOV. I3, 1915.

Inventor: Charles H. Hill,

His flttorneg.

I m ES H. HILL, OF SCHENEC'IADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SAFETY-STOP FOR SWITCHES.

Specification of Letters Patent.

Patented May at, acre.

To all whom it may concern:

Be it known that I, CHARLES H. HILL, acitizen of the United States, residing at Schenectad in the county of Schenectady, State of, ew York, have invented certain new and useful Improvements in Safety- Stops for Switches, of which the following is a specification.

The object of my invention is to provide a safety device for knife blade switches to prevent them from being closed accidentally. If a double throw knife blade switch is mounted so that the blades swing in a vertical direction there is a tendency for the blades to fall and make contact when the switch is open. There is also danger that such switches will he accidentally closed by reason of. carelessness onthe part of theattendant. The more particular object of my invention is to prevent accidents by reason of the closing of knife blade switches of the above-mentioned type at times when it is desired that they should remain open. It is not limited in its utility to this particu lar type of switch but may be employed with any form of knife blade switch irrespective of the way in which it is mounted.

My invention will best be understood by reference to the following description taken in connection with the accompanying drawing in which I have shown a side view of a switch provided with one of my devices. As

here shown the single pole double throw:

knife blade switch 1 has upper contact cli s 2 and lower contact cli s 3 mounted on t e base 4 in such a way t at the blade which is pivoted at 5 swings in a vertical direction. When the switch is open there is a tendency for the blade to fall and make contact with the lower clips. This tendency increases after the switch has been in service for some time and the usual friction in the pivotal mounting has decreased. There is also danger that a careless attendant will accidenta ly touch the handle 6 and close the switch on the lower contact. It has been customary heretofore to avoid this danger by providing separate blocks of in-. sulating material which fit into the clips 3 and prevent the blade fi'om making contact therewith. Such blocks however are easily misplaced and lost and are therefore inefiicient for roviding the desired safeguard. This dlsadvantage is overcome by my device which comprises a blade 7 having an insulating knob 8 on the end thereof and which is pivotally mounted at the point 9 adjacent the clips 3. When the switch is opened the device, which for convenience of description I term a safety stop, is placed in the osition shown in the drawing. The blade i is made to fit the contact clips 3 and its upward movement is limited by the usual shoulder 10, indicated by dotted lines, which is provided to limit the movement of the switch blade toward the base. The

safety stop is frictionally held in this '90 7 sition by the clips 3 and it will be apparent that it will be impossible to close the switch on the lower contacts until the safety stop is manually thrown down to the position indicatedby dotted lines where it does not interfere in any way with the operation of the switch.

While I have described and illustrated the application of my invention to a single pole double throw switch, it will be apparent that a stop such as the one I have shown will be equally effective with switches having more than one pole and that it may be applied to any knife blade switch, if desired, irrespective of the way in which it is mounted.

What I claim as new and desire tosecure by Letters Patent of the United States, is 2- 1. The combination with a switch having a knife blade and cooperating contact clips,

of a safety stop comprising a blade pivotally mounted adjacent one of the contact clips and adapted to be held in position by'said contact clips when the switch is open and an insulating member on said blade adapted to limit the movementof the knife blade.

2. The combination with a switch having a knife blade and cooperating contact clips, of means for limiting the motion of the knife blade toward the contacts comprising a member pivotally mounted adjacent one of the contact clips so as to swing in the same T direction as the knife blade and adapted to roof be held in position by the contact clips so as to limit the motion of the knife blade.

3. The combination with a switch having a knife blade and cooperatin contact clips,

5 of a safety stop comprising a lade pivotally mounted adjacent one of the contact clips so that its path of travel is partly coincident with that of the knife blade and adapted to be held in position by said contact clips so as to limit the movement of said knife 10 blade.

In witness whereof, I have hereunto set my hand this 12th day of November 1915.

CHARLES H. HILL.

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