Improvements in Rack Pulleys and in the Manufacture of the same.
Year: 1899

page_text: Date of Application, 17th May, 1899
PROVISIONAL SPECIFICATION.
Improvements in Rack Pulleys and in the Manufacture of the same.
I, THOMAS DOWLER GREEN, of The Dowler Engineering Company, of Burling-
ton Chambers, New Street, in the City of Birmingham, Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention relates to rack pulleys for tensioning or adjusting roller-blind
cords, and has for one of its objects, to provide a pulley the cord carrier of which
shall be self-locking or fastening in its adjusted position without the employ-
ment of springs, and for another object, to make the principal parts of the
article from sheet metal.
According to my invention, the article consists of a rack or sliding bar, pro-
vided with teeth upon its face, and having at its upper end, a roller or other
runner around which a cord to be tightened passes. This bar is arranged to slide
and work between a pair of ears of a fixed frame or attachment plate, and from
or upon which said ears, a swinging pawl or gravity catch is pivoted and so hung
that it is made to self engage with the rack teeth and hold the bar in a set posi-
tion against the upward pull of the tensioned cord, but on the said bar being
pushed down by hand, then its rack teeth lift and wipe under the pawl.
It is understood that the gravity catch, which consists of an arm jointed at one
end and having a tooth, plate or equivalent catch projection near that end, turns
upon a pin directed between the ears and arranged in such a position that the
arm counterpoises the catch and normally keeps up to and into engagement
with, the teeth, whilst the liberation of the bar is effected by lifting the end of
the arm and taking its catch out of engagement with the rack.
The self-locking gravity lever may be made from a flat piece of metal of about
the same breadth as the rack, the one end of which is returned or turned over to
form a sleeve to take over the joint pin, whilst an adjacent part is folded upon
itself to form the catch.
The carrier frame or attachment plate is made from a cruciform or T-shaped
piece of metal, the side branches of which are turned up into ears to form the
bearings for the joint pin of the gravity catch.
The slide or rack bar may also be made from a strip of metal, whose teeth are
formed by raising or embossing a series of cross ribs thereon and also, if neces-
sary, troughing or corrugating the same longitudinally at the edges to give
stiffness, whilst the one end may be provided with a pair of ears between which
the bearing pin of the cord roller is disposed. The said roller or runner may be
made of metal, wood, china or the like.
Instead of the teeth being embossed, they may be formed by piercing the
metal, or by slitting it at parts and turning them outwards.
"
1001
7
10
1000

page_text: Improvements in Rack Pulleys and in the Manufacture of the same.
I, THOMAS DOWLER GREEN, of The Dowler Engineering Company, of Burling-
ton Chambers, New Street, in the City of Birmingham, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to rack pulleys for tensioning or adjusting roller-blind
cords. and has for one of its objects, to provide a pulley the cord carrier of which
shall be self-locking or fastening in its adjusted position without the employ-
ment of springs, and for another object, to make the principal parts of the
article from sheet metal.
Figure 1 of the accompanying drawing represents a front elevation of a self-
locking rack pulley constructed in accordance with my invention.
Figure 2 is an edge view of the same..
Figure 3 represents a complete vertical section and Figure 4 an end view
looking from the top.
Figure 5 is a separate elevation of the rack plate, which is made from a blank
of sheet metal, and. Figure 6 is an edge view thereof.
Figure 7 represents a front elevation of the self-acting catch or fastener and
the stationary attachment plate of the fitting separately.
Figure 8 shows a side view of the same whilst Figure 9 represents this part
of the article in vertical section..
The same letters of reference indicate corresponding parts in the several
figures of the drawings.
According to this form of my invention, the article consists of a rack or sliding
plate or bar a, provided with a series of transverse teeth a', upon its face, and
having at its upper end, a roller or runner 6 around which a cord to be tightened
passes. This rack plate or bar is arranged to slide and work between the over-
hanging edges 2, of a fixed carrier or attachment plate c, which acts both as a
guide for the vertically adjustable rack bar, and also as a carrier for a swinging
pawl or gravity catch which is pivoted to a cross pin d, directed between
ears of the plate c, and is so hung that its nose ², is made to self-engage under
or with one of the teeth of the rack plate, and hold the said plate in a set position
against the upward pull of the tensioned cord, but on the said bar being pushed
down by hand, then its rack teeth lift, and wipe under, the pawl or loosely hung
catch.
The gravity catch, which consists of an arm jointed at one end and having the
nose, tooth or equivalent catch projection d², arranged adjacent to the joint, turns
upon the pin directed between the ears of the fixed attachment plate and is
arranged in such a position that the lower end 3, of the arm counterpoises the
catch part and normally keeps the latter up to and into engagement with, the
teeth whilst the liberation of the rack plate or bar is effected by lifting the end
of the arm and taking its catch out of engagement with the rack.
upon
The self-locking gravity lever may be made from a flat piece of metal of about
the same breadth as the rack, the one end of which is returned or turned over to
form a sleeve to take over the joint pin whilst an adjacent part is folded
itself at to form the catch. A counterpoise weight d, is preferably secured to
the tail end of the gravity catch by folding the edges of the sheet metal over
the edges of the weighting disc.
The carrier frame or attachment plate is made from a cruciform or T-shaped

page_text: piece of metal, the side branches of which are turned up into ears to form the
bearings for the joint pin of the gravity catch.
The slide or rack bar may also be made from a strip of metal, whose teeth are
formed by raising or embossing a series of cross ribs thereon and also, if neces-
sary, turning back the metal at the edges a², to give longitudinal stiffness to the
plate whilst the one end may be provided with a pair of ears a³, between which
the bearing pin at, of the cord roller is disposed. The said roller or runner b
may be made of metal, wood, china or the like.
Instead of the teeth being embossed, they may be formed by piercing the
metal, or by slitting it at parts and turning the slit-parts outwards.
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:
First: A rack pulley, or self-locking rack pulley, consisting of a sliding or
adjustable plate or bar having a series of transverse ribs or teeth, and a station-
ary attachment plate, which constitutes a guide for the rack, and has pivoted to
it, a gravity catch or pawl, whose nose or tooth is adapted to be engaged by, or
automatically engage with, the teeth of the said rack, substantially as herein des-
cribed and also as set forth in the accompanying drawing.
:
Secondly In the manufacture of rack pulleys of the kind referred to in the
preceding Claim, making the gravity catch from a folded blank of sheet metal,
one end of which is formed into a sleeve to encircle the bearing or joint pin,
whilst an adjacent part is folded upon itself to form the catch, substantially as
herein described, and also as set forth in the accompanying drawings.
Thirdly-In the manufacture of rack pulleys of the kind referred to in the
First Claim, making the carrier plate from a cruciform or T-shaped piece of
metal, the side branches of which are turned up into ears to form the bearings
for the joint pin of the catch substantially as herein described and also as set
forth in the accompanying drawings.
Fourthly: In the manufacture of rack pulleys of the kind referred to in the
First Claim, making the slide or rack bar from a strip of sheet metal in which
a series of transverse ribs or teeth are formed by embossing or slitting the metal,
whilst the one end is provided with a series of branches or ears from which the
bearings for the pin of the cord roller are made substantially as herein described
and also as set forth in the accompanying drawings.
Dated this 20th day of December 1800
THOMAS DOWLER GREEN.
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.