Improvements in Door Latches.
Year: 1889

page_text: Date of Application, 3rd Dec., 1889-Accepted, 4th Jan., 1890
COMPLETE SPECIFICATION.
Improvements in Door Latches.
I, EDWARD STEVENS WINCHESTER, residing at Number 512 Washington Street,
Dorchester District, Boston, in the County of Suffolk, and State of Massachusetts,
United States of America, Mechanical Engineer, 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 relates to an improvement in that class of latches in which a pivoted
latch-bolt is maintained in a retracted position against the influence of a projecting
spring by a detent or catch which is arranged to be lifted out of contact with the
latch-bolt by a releasing device acting thereon in a lateral direction when the door
encounters the door jamb.
In the present invention a spring detent or catch is arranged to frictionally engage
a swinging latch-bolt on its end so that the same can be held thereby at any point in
its path of movement, the said detent being combined with a releasing device acting
laterally thereon to release the bolt.
In the accompanying drawings,
Figure 1 is a horizontal cross-section through my improved lock and a portion of the
door jamb.
Fig. 2 is a section of the same on the line x x of Fig. 1.
Fig. 3 is a section on the line y y of Fig. 1.
Referring to the drawings, A represents the lock casing consisting as usual of the
casing a, and the inner casing a¹. B and B represent the inner and outer knobs
respectively, the former provided with the shank or hub b, and the latter with the
spindle b', which passes therethrough and is screwed or otherwise suitably fastened
to the knob B. Cis a spring located on the spindle between the shank & and the
knob B' to hold the inner knob B securely up against the hub of-the-lock. Dare
tumblers formed on the shank, as usual, by which reciprocating frames E, E' are
operated. F represents a latch-bolt pivoted in the end of the casing by the pivot
pin f, and formed with the side walls f₁, f, and an end wall f³. G represents a
spring for projecting the latch-bolt which encircles the pivot pin and bears on the
latch-bolt and casing of the latch respectively. H represents a bail pivoted between
the walls of the latch-bolt and extending therefrom in position to be engaged by the
reciprocating frames E, E¹.
I represents a spring detent or catch having one end securely fastened to the inner
face of the outer casing a, and extending therefrom in the path of the outer curved
end of the swinging latch-bolt. This detent is arranged to bear on the outer end of
the swinging latch-bolt and to frictionally hold the same until lifted out of contact
therewith by a releasing device hereinafter described. It will be observed that by
means of this detent, arranged in the manner shown, the bolt may be either held in a
wholly retracted position or in a partially retracted position as desired.
As the bolt is usually wholly retracted, I have provided the detent with a projection
or a shoulder f, adapted to engage within a notch t formed in the outer surface of the
latch-bolt, the position of the notch with relation to the shoulder being such that the
latter will enter the notch when the bolt is wholly retracted. This construction
enables the spring to more securely hold the latch, and serves as a stop to limit its
inward motion.
In order that the detent may be lifted out of contact with the latch-bolt to release
the same, I provide the sliding plate K which is mounted in the end of the casing.
This plate is provided with the central tongue k, which extends between the walls of
the latch in contact with the free end of the detent as shown.

page_text: It is further provided on either side of the central tongue with two tongues k¹ and k³,
which extend forward and serve to guide the plate.
L represents a plate or projection secured to the jamb of the door in position to
encounter the end of the plate K when the door is closed, and acts to push the plate
inward and lift the detent out of engagement with the latch-bolt and thus release the
same.
It is to be understood that I do not confine myself to the exact construction shown
for frictionally holding the latch-bolt, as the same can be variously.modified without
departing from the limits of my invention, the essence of which consists in a detent
arranged to bear on the outer end of a swinging latch-bolt, and to frictionally hold the
same in any position to which it may be retracted.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a latch, the latch-bolt pivoted at one end and having its opposite end free to
move in the arc of a circle, a spring for projecting said latch-bolt, suitable mechanism
for retracting the same and a detent arranged to bear on the end of the latch-bolt and
to frictionally hold the same in any position to which it may be retracted, in com-
bination with the lateral releasing device adapted to lift the detent out of engagement
with the latch-bolt.
2. In a latch, the latch-bolt having one end pivoted and the opposite end provided
with the notch t, and free to swing in the arc of a circle, the bolt projecting spring,
the detent arranged to bear upon and hold the end of the latch-bolt frictionally; and
having also the shoulder to engage the bolt and positively hold the same when fully
retracted.
Dated this 3rd day of December 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.