IMPROVE- MENTS IN SELF-ACTING BOLTS OR CATCHES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by William John Hinde at the
Office of the Commissioners of Patents, with his Petition, on the
29th October 1875.
I, WILLIAM JOHN HINDE, of Euston Road, in the County of Mid-
dlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN SELF-ACTING BOLTS OR CATCHES," to be as follows:-
This Invention relates to improved methods of constructing bolts used
for the purpose of fastening doors, and is especially applicable to all
folding doors, such as the doors of wardrobes, cabinets, French case-
ments, and cupboards, and to other positions where (as in double doors)
the first door has to be bolted or fastened before the second one is closed
and locked; it has for its object further improvements in the self-acting
bolt or catch (for similar purposes) for which I obtained Letters Patent
dated April 28th, 1875, and numbered 1565.
In the Specification of the Letters Patent above referred to, and in the
Drawing accompanying the same, is described and shewn a self-acting
bolt or catch, in which a striking catch is arranged at one end of a bar
turning in bearings, whilst a locking catch is arranged at the other end

page_text: of the same bar, so that when the second door is closed it strikes the
striking catch and forces the bolting catch into the other door (which
has been first closed), a spring or weight being used to bring the catches
and bar into their original position when necessary.
My present Invention consists of improved methods of actuating and
arranging self-acting bolts or catches (to be used for similar purposes)
so that the bar and the bearings in which it turns, and the spring or
weight, are unnecessary, and the bolt is lighter, simpler, and cheaper
than such bolts as heretofore ordinarily constructed and used.
I take a plate of brass, iron, or other suitable material, and of any
convenient size and thickness, and preferably of a shape triangular or
nearly so, and I arrange it so that it can turn (in its own plane) upon a
centro near one of its corners. This centre is fixed to the edge of the
door frame, above or below the door, or in the door itself, and may
consist of a screw or pivot passing through a hole in the plate into the 1
door frame or door, or of a plate carrying a pivot, the plate being
screwed or fixed to the door frame or door. The sides of the moveable
plate adjoining the centre upon which it turns as described are arranged
so that when the first door is closed its edge strikes one of the sides of
the plate, which it forces round until its other side projects sufficiently a
to be struck by the edge of the second door, when the latter is shut.
The plate is thus again forced back until a projection upon the edge
first described enters a corresponding hole in the edge of the first door,
which is thus bolted or retained in its position until the second door is
again opened, and the plate thus released. The hole in the door may
have its edge formed of a metallic plate, made adjustable to compensate
for any shrinking in the door or frame.
The projection described upon the edge of the plate is made of such a
shape that when the plate is released by the opening of the second door
the plate is pushed back by the first door, when the latter is opened in
its turn.
Instead of a projection upon the edge of the plate a recess may be
formed upon it, fitting a pin or projection in the edge of the door, and a
friction roller may be added to the plate (or to the door) for the purpose
of reducing the friction whilst the plate is pushed back by the first door
being opened.
A spring may be used to bring the plate back to its desired position.

page_text: I make a slot in the plate on a projecting or other guide working
against pins or other stops, so that the movement of the plate in either
direction is limited.
Instead of being nearly triangular, as described, the moveable plate
may be made in the shape of a semicircle (more or less), so that the
projection or recess upon it passes behind and round the corresponding
recess or pin in the edge of the door, which is thus more firmly bolted
and held fast.
Another novel form of bolt, which I sometimes use for the same
purposes as those already described, consists of a bar turning upon a
centre fixed inside the door frame, and so that a projection upon its
outer end drops into a corresponding hole in the edge of the door first
closed. This projection is made of such a shape (having its back edge
inclined) that the door can be opened when desired, and raises the lever.
To a suitable point in the side of the lever I suspend a bar or plate of
such length and shape that it is struck by the upper edge of the second
door when the latter is closed, and its lower end is thus raised and forced
under the door frame to which the lever is fixed, and the latter is thus
prevented from rising to release the first door until the second door has
been again opened.