IMPROVEMENTS IN SPRINGLESS LOCKS
Year: 1885

page_text: I CHARLES DOHRN DOUGLAS of 15 Queenhithe, Upper Thames Street in the
City of London, Lock Manufacturer do hereby declare the nature of my invention..
for IMPROVEMENTS IN SPRINGLESS LOCKS, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
The object of my present improvements in springless locks is to enable a
reduction in their thickness to be effected without detracting from their efficiency
or durability, or reducing their other dimensions; and thus to adapt them for use
with doors of light make and little thickness.
My invention relates more particularly to springless mortise locks, and enables
the width of such locks to be reduced to half an inch or even less, while the locking
power of the weight is as great or greater than in locks of equal area and greater
thickness.
These important advantages I am enabled to secure by the use in such locks of a
novel construction of the weight or weights by which the locking catch or bolt is
retained in its locked position, and irrespective of the means employed for operating
the said weight in withdrawing the bolt or latch.
According to any invention I construct my weight by casting a frame of iron or
brass and of rectangular or other suitable form, with grooves or a fillet on its inner
wall, and by filling the hollow centre of the said frame with lead or lead alloy,
which lead engaging with the grooves or fillet in the frame will be firmly united
thereto. I preferably fill the hollow centre of the iron or brass frame with lead
by casting; but it may also be filled by inserting a roughly cast block of lead
in the frame and expanding the said block laterally by pressure, or by equivalent
means.
The invention is illustrated in the accompanying Drawing in which
Fig 1 is a plan view of a lock fitted with a composite metal weight constructed
according to my invention.
Fig: 2 is a section of the weight on the line 1-2 of Fig: 1, and
Fig: 3 is a section of the frame of the weight, before the filling up of the hollow
centre thereof with lead or lead alloy.
A is the frame of the weight of hard metal preferably iron or brass cast with a
pin a for the attachment of the locking catch and with a hole for the reception of
the pivot pin or stud b on which the said frame is fulcrummed.

page_text: The inner wall of this frame A is provided with a fillet or rib c formed in one
with it at the time of casting but it might have grooves or indentations or
projections answering the same purpose as the fillet or rib c; which is to grip and
retain the lead B when run or pressed into place within or between the walls of
the frame A.
A single fillet or rib c running around the entire inner wall of the frame A, as
indicated in Fig: 3, is very efficient, and the lead thus united to the frame will
remain immovable either by concussion or wear.
From the foregoing it will be seen that I am able by substituting my improved
composite metal weight for the iron or brass weights hitherto used in springless
locks, to fit the working parts of an ordinary 5/8" lock within a lock case only
half-an-inch in thickness, and to obtain as much, if not more, power in the lever
action than was formerly obtained in a lock having a 5/8" lock case, without
increasing the area covered by the weight or detracting from its simplicity or
durability which are among the great advantages of these springless locks; and by
this means springless locks can be used where otherwise on account of their
thickness it would be impossible to use them.
In some cases the lead filling may unite or occupy the space between an inner
and an outer frame each provided with an interlocking fillet or its equivalent for
the purpose above set forth, thus providing a composite weight of the character
above described suitable for use with a follower working in the centre of, instead of
below, the weight.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
The means above described for reducing the thickness of springless locks without
detracting from their efficiency and durability.