Year: 1887

page_text: Date of Application, 18th Aug., 1887.
Specification Accepted, 20th Sept., 1887.
[Communicated from abroad by EDWARD STEVENS WINCHESTER, of Boston,
Massachusetts, United States of America, Mechanical Engineer.]
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, & Co. Patent Agents, 45
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention has reference to that class of knob door-latches in which the latch-
bolt, projected by a spring and retracted by a knob or its equivalent, is combined with
devices to hold it in its retracted position until the closing of the door. Heretofore
these detaining devices have been constructed to engage a notch in or shoulder upon
the bolt, and acted to hold the latter only when it was fully retracted. It frequently.
happened, therefore, that the latch would be retracted a sufficient distance to release
the door, but not sufficiently to be held by the detent; the latch being then thrown
forward by its spring while the door was open, it would offer all the disadvantages of
an ordinary latch in closing the door, and, if made with a square end, would strike
against and mutilate the casing.
The aim of the present invention is to avoid the difficulties which were incident to
the old construction, and to provide means by which the latch bolt will be automatically
secured at any point to which it may be retracted and automatically released on the
closing of the door, and also to prevent its release by children or other meddlesome
persons.
To this end the invention consists, first, in combining with the latch-bolt a detaining
device acting with frictional effect to hold the bolt in any position in which it may be

page_text: placed, and, second, in combining with the said frictional device and the means for
disengaging the same, a special spring of such strength as to prevent the releasing
devices from being operated by hand.
This invention is susceptible of embodiment in various forms, which will suggest
themselves to the skilled mechanic after a reading of this specification, but that form
of embodiment is represented in the drawings which is recommended as best adapted
for ordinary use.
In the accompanying drawings, Figure 1 represents a horizontal section through
a latch on the line of Fig. 2. Fig. 2 is a face view of the same, the front of the
casing being removed to expose the internal parts to view.
"
Referring to the drawings, A represents the lock-casing; B the latch-bolt urged
outward by a spring C; D a second bolt, commonly known as a yoke," arranged to
engage a shoulder on the latch-bolt to effect its retraction; E a spring by which the
yoke is urged forward, and J the stump through which the knob-spindle passes, and
which is provided with projections to engage the arms of the yoke and draw the same
backward as the knob is turned.
So far as described the foregoing parts are of substantially the samo construction
as in other latches at present known in the art.
In applying this improvement, the latch-bolt is provided with a lateral arm or pro-
jection a, and secured to the inside of the lock-case is a strong longitudinal spring F,
having its free end arranged to bear against the arm a. This spring is constructed of
such strength that the friction upon the arm a will be sufficient to resist the action of
the spring C and hold the latch-bolt in any position to which it may be retracted―
that is to say, in any position between the two extremes of its movement. Thus con-
structed and applied, the spring F constitutes a frictional detent or detaining device
to hold the latch-bolt in any position in which it may chance to be left when the door
is open.
The essence of this invention resides in detaining the bolt by friction, and it is
manifest that the form of the spring and its arrangement and connection with the bolt
may be modified at will, provided only the bolt is held by frictional effect.
For the purpose of relieving the bolt from the action of the detaining spring F
when it is to be projected, a transverse pin G is mounted in the lock-case, bearing at
one end on the detaining spring, and in the outer side of the case a second pin й is
mounted, its outer end projected in position to encounter the door jamb or casing
when the door is closed, and its inner end in position to act upon the pin G, and cause
the latter to lift the spring F from the bolt. When this action occurs, the bolt is
immediately projected by the spring ()
The pin His flanged or headed at its inner end, and is insérted to its place from the
inside of the mortise in the door. In order to prevent it from being forced inward
by hand, either accidentally or purposely, a second spring I is provided, secured to
to the lock-case, and bearing against the inner end of the pin H, as shown in Fig. 1.
This second spring I, the sole purpose of which is to prevent the pin H from being
forced inward by hand, is made of such strength that, although it will resist the
pressure of the finger upon the pin, it will yield when the pin encounters the door-
casing, and thus permit the automatic release of the latch-bolt. In practice the
spring I is commonly made much stronger than the other. If desired, a lip or
shoulder may be combined with the friction spring to engage the bolt and hold the
same with a positive action when it is fully retracted. When this device is used, the
bolt will be held by frictional effect until it reaches its innermost point, when
the positive locking action will occur.
Having now particularly described and ascertained the nature of the said invention,
as communicated to me by my foreign correspondent, and in what manner the same
is to be performed, I declare that what I claim is :-
'
1. In combination with a latch-bolt and a spring to project the same, the detent,
substantially as described, bearing normally on said bolt, and acting frictionally to

page_text: hold the same, whether wholly or partially retracted, against the influence of the
projecting spring, and a lateral pin or projection for lifting the detent out of action.
2. In combination with the latch-bolt and its projecting spring, the friction-spring F,
acting upon the bolt and adapted to hold the same against the influence of the pro-
jecting spring, the pin (, to act upon the detaining spring, the projecting pin H,
extending beyond the lock, and the spring I, acting upon the pin H, as described.
Dated this 18th day of August 1887.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.