Untitled record

D. D. ELDRIDGE.

Key-Fasteners.

No.155,642.

Patented Oct, 6,1874.

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THE GRAPHIC CO.PHOTO-LITH.39&amp;4-1 PARK PLACE,N.Y. ·

United States Patent Office.

DANIEL D. ELDRIDGE, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN KEY-FASTENERS.

Specification forming part of Letters Patent No. 155,642, dated October 6,1874; application filed July 31,1874.

To dll whom it may concern:

Be it known that I, Daniel D. Eldridge, a citizen of Chicago, State of Illinois, have invented a new and useful Improvement in Burglar - Proof Attachments for Locks, of which the following is a clear, full, and exact description, reference being had to the. accompanying drawings makirig a part of this specification, in which—

Figure 1 represents the key-fastener. Fig. 2 shows the key-hole plate with guide and spring. Fig. 3 shows the key-hole plate, with the fastening device attached.

The object of my invention is to provide means by which a key may be secured automatically in a door-lock on the inside of the room, so as to prevent burglars turning the key by means of nippers and other instruments from the outside; and it consists in an automatic escutcheon or key-lock constructed and applied as hereinafter shown.

To enable others skilled in the art to make and use my invention, I will proceed to describe the particular manner iu which I carry it out.

In the drawings, B represents the key-hole plate, and a the escutcheon or locking device. The upper portion of the escutcheon is made broad, as shown in Fig. 1, one side of it being slotted, as shown at δ, and the opposite side curved at c to form a handle or thumb support, by which the escutcheon may be readily operated. The handle portion c of the escutcheon. extends slightly above the slotted portion, as shown at d, and forms a square shoulder, which comes in contact with the guide h on the key-hole plate, and thus forms a stop for the escutcheon when thrown by the spring i into a locking position, which is the case when the slot δ passes over the square shank of the key of the lock, fitting it snugly, and not allowing the key to be turned until the escutcheon is removed or drawn back, as shown in Fig. 1. The guide Iron the key-hole plate holds the upper portion of the escutcheon in position, and at the same time allows it to slide to and from the key-hole. The lower portion of the escutcheon or locking device S is made concavo-convex, in order to accommodate the spiral or coil spring which holds it to its work. By this construction I completely conceal the spring, which is, therefore, not liable to become injured or get out of position. The one end of the coil-spring is secured to the escutcheon, and the opposite end to the key-hole plate, while the screw/serves as a pivot on which the escutcheon works, and at the same time secures the escutcheon to the body of the lock.

It is evident from the above description, that if a key with a square shank, fitting the' slot δ, be inserted in the key-hole, as soon as the-escutcheon is released from the thumb, it will spring forward and seize the shank of the key, and prevent the possibility of its being turned from the opposite side of the door. The action of the spring carries forward the escutcheon, and causes it to act automatically in securing the lock against burglars, and thus avoids the possibility of negligence in moving forward the locking device.

I am aware that it is not new to use a slotted escutcheon, and therefore do not claim this broadly; but