Improvements in Fasteners for Window Sashes, Casements, Doors, and other similar purposes.
Year: 1895

page_text: Date of Application, 31st Aug., 1895-Accepted, 5th Oct.. 1875
COMPLETE SPECIFICATION.
Improvements in Fasteners for Window Sashes, Casements, Doors,
and other similar purposes.
I, PERCY BIRKETT of 6 Montgomery Street Hove Sussex 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 has for its object the better securing of window sashes, casements,
& doors and the prevention of their being opened from the outside and it is so
arranged that when applied to window sashes the act of rotating the cross bar
connecting the top & bottom sashes through the necessary angle to bring it across
the top & bottom sashes in the ordinary way at the same time actuates a locking
device which secures the cross bar from being moved from such position from the
outside of the window or by means of pressure applied at any point except at the
kuob provided for the purpose. Having now described the nature of my invention
I will proceed to show by means of drawings & description the way I prefer to
carry the same into effect."
DESCRIPTION OF DRAWING.
Fig. 1 shews the position of the various parts when the fastener is closed across
the sashes.
Fig. 2 shews the same when the fastener is open.
Fig. 3 shews a cross section through cross bar & locking plate.
Fig. 4 shews the end of an alternative form of locking plate in which the knob
arm is at right angles to the axis of the cross bar.
In the above figures A is the baseplate of an ordinary form of sash fastener B is
the cross bar of same capable of turning upon a centre C and being held in position
by a spring E in the usual way. To the cross bar B is attached a plate of metal
or other suitable material hereinafter called the locking plate by means of a pin G
forming an axis about which it is capable of turning freely.
The end H of this locking plate has its edge formed to a radius struck from the
centre G and this edge is arranged nearly in contact with the upright part J of the
baseplate A. The locking plate is continued in a contrary direction beyond
the centre G and to its end the knob K is attached.
Towards the base of the locking plate and in a suitable position is a slot L which
enables it to move clear of the pin C when turning on the centre G. The part M
of the locking plate is turned vertically upwards as shewn in section on Fig. 3 and
when the cross bar B is in the position shewn in Fig. 1 this vertical side of the
locking plate rests in contact with it & the catch N which may be of the ordinary
kind.
Q
The action of the fastener is as follows-When pressure is applied to the knob K
to turn the cross bar in the direction shewn by the arrow on Fig. 2 this cross bar
turns upon its centre C and at the same time the same pressure turns the locking
plate F upon its centre G & this movement is continued until arrested by the side
of the locking plate coming in contact with the side of the stop N when the cross
bar & locking plate will be in the position shewn in Fig. 1.
If now a knife or other implement be introduced through the space O between
the sashes and pressure applied to the side M of the locking plate the latter together

page_text: with the cross bar B moves slightly upon the centre until the projecting part H
of the locking plate comes in contact with the upright part J of the baseplate thus
arresting further movement & effectually locking the fastener. In order to reduce
to a minimum the motion of which the cross bar is capable before becoming locked
I sometimes emboss inwards the upright part J of the baseplate A as shewn by the
dotted lines in Fig. 1.
When it is required to open the fastener pressure is applied to the knob K in the
direction indicated by the arrow on Fig. 1, whereby the locking plate is turned
upon its centre G until arrested by the pin C in the slot L when both locking plate
& cross bar move together upon the centre C until they assume the position shewn
in Fig. 2. when the sashes are free to open.
I wish it to be understood that I do not confine myself to the exact form & mode
of carrying my invention into effect herein described as it may be varied to suit
circumstances.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
(1.) The use of a cross bar or trigger consisting of two members forming a
compound lever; the first member turning about a centre at one end upon a fixed
base and the second member being moveable about a centre fixed at some suitable
point along the first member and so arranged that when pressure is applied to that
end of the second member remote from the centre upon which the first member
turns the cross bar or trigger is by this pressure both turned upon its centre and
locked and by reversing the pressure is unlocked & turned back, in either case by
a single movement of the hand as herein described.
(2.) The combination of the various parts arranged & working together for the
uses & purposes substantially as herein set forth & described.
Dated this 31st day of August 1895.
PERCY BIRKETT.