An Improved Safety-hinge, applicable to Folding-ladders.
Year: 1890

page_text: Dite if Application, 12th Mar.. 1890
Complete Specification Left, 12th Dec., 1890-Accepted, 14th Feb.. 1891
PROVISIONAL SPECIFICATION.
An Improved Safety-hinge, applicable to Folding-ladders.
We, THOMAS BIRTWISTLE, of 42, Belvedere Road, Burnley, in the County of
Lancaster, Ironmonger, and SQUIRE BARDSLEY, of Master Street, Burnley,
Millwright and Pattern Maker, do hereby declare the nature of this invention to
be as follows:-
This invention relates to the construction of a hinge and lock-piece applicable to
folding ladders, and is designed to prevent the loose leg of the ladder from shifting
its position when set outwards. The hinge consists of two limbs one attached to
the ladder and the other to the movable leg. The extent of movement of the leg
outwards is determined by one or more stops cast or otherwise secured to the hinge
fixed to the ladder. The limb attached to the movable leg is carried a little above
the joint of the hinge and terminates in a suitable slot or recess which is capable of
engaging with a vertical slide piece moving in a guide-way, fixed to the ladder,
above the recess. In opening the leg, the vertical slide-piece is raised by an incline
on the limb of the loose leg until arrested by the stops, at which time the vertical
slide piece falls into the recess or slot of the limb and safely locks the leg.
To shut the ladder a button or finger bit attached to the vertical slide-piece is
raised by hand. The two limbs of the hinge may be extended a little above the
joint with a pin hole in each extended part so that when the hinge is opened
outwards to the stops both holes are opposite, in which position a pin is inserted in
the holes to lock the hinge, in substitution of the vertical slide piece. Or, the lock
piece may consist of a pair of small folding arns connected together after the
fashion of a rule joint. One arm so connected is attached to the limb of the loose
leg, and the other to the limb of the ladder hinge. When the ladder is closed the
arms are in a folded position, but when the ladder is open the two arms are
stretched out horizontally so as to secure the hinge. When stretched the arms
may be further secured, if desired, by a pin inserted through a hole in each arm.
Dated this 11th day of March 1890
COMPLETE SPECIFICATION.
An Improved Safety-hinge, applicable to Folding-ladders.
WC, THOMAS BIRTWISTLE, of 42, Belvedere Road, Burnley, in the County of
Lancaster, Ironmonger, and SQUIRE BARDSLEY, of Master Street, Burnley,
Millwright and Pattern Maker, 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 the construction of hinges and lock-pieces applicable to
folding ladders and is designed to prevent the loose leg of the ladder from shifting
its position when set outwards. The hinge consists of two limbs, one attached to
the ladder and the other to the movable leg. The extent of movement of the leg
outwards is determined by one or more stops cast or otherwise secured to limbs of
the hinge, fixed to the ladder. The limb attached to the movable leg is carried a
little above the joint of the hinge and terminates in a suitable slot or recess, which
is capable of engaging with a vertical slide piece moving in a guide-way fixed to a
ladder above the recess.
In opening the leg, the vertical slide-piece is raised by an incline on the limb of
the loose leg, until arrested by the stops, at which time the vertical slide piece falls
Dr7

page_text: into the recess or slot of the limb, and safely locks the leg. To shut the ladder, a
button or finger-bit, attached to the vertical slide piece, is raised by hand.
In substitution of the vertical slide-piece, a pair of small folding arms may be
employed having their outer extremities, attached one to each limb of the hinge.
When the ladder is closed, the arms are in a folded position; but when the ladder
is opened, the two arms are stretched out horizontally so as to secure the hinge.
In the accompanying drawings,
Fig. 1 represents a folding ladder, constructed in accordance with our invention.
The hinge is composed of two limbs A and B, which are jointed or hinged together
at C. The former is provided with stop or shoulder-pieces D and E, whilst the
latter is similarly provided with stop or shoulder pieces F and G. These determine
the extent of movement outwards of the movable leg H from the ladder I. To the
ladder is fixed bracket J, in which slides vertical slide-piece K, capable of engaging
with projection or sneck L, when the stop or shoulder pieces of one limb are against
those of the other as seen in Fig. 1, and prevents the leg H. from moving inwards.
The vertical slide piece K is disengaged from the projection L by the button or
finger-piece M, when it is required to close the ladder.
In Figs. 2 and 3 the vertical slide piece K, seen in Fig. 1, is dispensed with, and
a pair of small folding arms N and substituted, having their outer extremities
attached to the ends of the limbs A and B. These are represented as being opened
out in Fig. 2 when the stop and shoulder-pieces of one limb are brought against
those of the other, and at which time, the folding arms N and are horizontally
:stretched, so as to prevent the two limbs moving inwards.
When the two limbs A and B are closed as seen in Fig. 3, the folding arms N
and Owill-then-assume a. vertical position.
Having-now-particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed;-we-declare that what
we claim is
1. In a hinge applicable to folding ladders, stop or shoulder pieces D, E, F
and G, substantially as described and illustrated.
2. In a hinge applicable to folding ladders, the combination of stop or shoulder-
pieces D, E, and G and vertical slide piece K, substantially as described and
illustrated in Fig. 1.
3. In a hinge applicable to folding ladders, the combination of stop or shoulder-
pieces, D, E, F and G and folding arms N and O, substantially as described and
illustrated in Figs. 2 and 3.
Dated this 11th day of December 1890.
THOS. RICHMOND,
Agent.