Improvements in Clutch Mechanism Applicable for Driving the Feed Motion of Sewing Machines or for Driving other Mechanism or Preventing Back Movement.
Year: 1887

page_text: Date of Application, 16th Feb., 1887
Complete Left, 15th Nov., 1887
Complete Accepted, 30th Dec., 1887
Improvements in Clutch Mechanism Applicable for Driving the
Feed Motion of Sewing Machines or for Driving other Mechanism
or Preventing Back Movement.
1, HENRY BIRCH of 99 Kingsdown Parade Bristol, Engineer do hereby declare
the nature of this invention to be as follows:-
The apparatus as applied to the feed motion of sewing machines or to other
machinery having an intermittent feed consists of a ring or wheel so mounted as to
rotate easily but not too freely, and having a cylindrical flange. This wheel receives
its motion from a nipping lever having no fixed fulcrum but carrying a pair of dogs
or nipping instruments; these are mounted loosely on studs upon the lever and abut
on the cylindrical flange of the ring or wheel one on either side. The lever extends
to the opposite side of the ring or wheel and here by a suitable connection a to and
fro movement is imparted to it.
As the lever commences to swing in one direction the two studs upon it not being
set on the same radial line approach the flange of the ring or wheel and cause it to be
nipped by the dogs. As soon as the flange is nipped no further motion of the lever
can take place except the ring or wheel be carried round with it and hence the ring
or wheel is moved round a stop longer or shorter as may be required. When the
return motion of the lever commences the dogs separate and release the flange and a
spring then draws back that end of the lever upon which the dogs are mounted, the
ring or wheel meanwhile remaining stationary. The dogs being moveable upon studs
upon the nipping lever operate very much more efficiently than nipping projections
forming part of the lever which have before been employed, they greatly extend the
area of effective nipping surface and thereby wear is lessened and slipping is
prevented.
When the apparatus is applied to a sewing machine, the outer periphery of the ring
or wheel is generally roughened and the work made to rest upon it so that the work
may be carried forward intermittently as the ring rotates in the manner well known
as wheel feed machines.
In place of the two dogs being on opposite sides of a cylindrical flange they might
be set in opposite directions in a cylindrical groove.

page_text: Or similarly if a straight movement is to be imparted or prevented the two dogs
may be one on either side of a straight rib or placed in opposite directions in a straight
groove.
For preventing the cages of hoists from dropping in case of breakage or severing
of the lifting rope similar nipping levers carrying moveable dogs may be mounted
upon the cage to grip and hold on to one of the fixed guides or on to a fixed bar
should the rope fail. The apparatus may be used in duplicate with the pivot of the
lever arm of one pair of dogs on one side of the fixed bar and the other on the opposite
side. The weight of the cage hanging on the lifting rope may be made to keep the
levers out of action so long as the rope remains intact so that the cage may be raised
or lowered freely and springs may be used to instantly turn the levers into position
for the dogs to hold on to the bar and prevent the cage from dropping whenever the
rope fails.
Similar nipping levers carrying moveable dogs and acting in the above manner
may also be used for controlling the raising and lowering of window sashes, shutters
blinds etc. They may also be used as a means in conjunction with a handle treadle
or other similar device of communicating motion to bicycles tricycles sewing machines
and other machines or vehicles similarly driven.
Improvements in Clutch Mechanism Applicable for Driving the
Feed Motion of Sewing Machines or for Driving other Mechanism
or Preventing Back Movement.
1, HENRY BIRCH of 99 Kingsdown Parade, Bristol, 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 :-
The apparatus as applied to the feed motion of sewing machines or to other machinery
having an intermittent feed consists of a ring or wheel so mounted as to rotate easily
but not too freely, and having a cylindrical Hange. This wheel receives its motion
from a nipping lever having no fixed fulcrum but carrying a pair of dogs or nipping
instruments; these are mounted loosely on studs upon the lever and abut on the
cylindrical flange of the ring or wheel one on either side. The lever extends to the
opposite side of the ring or wheel and here by a suitable connection a to and fro
movement is imparted to it.

page_text: As the lever commences to swing in one direction the two studs upon it not being
sot on the same radial line approach the flange of the ring or wheel and cause it to be
nipped by the dogs. As soon as the flange is nipped no further motion of the lever
can take place except the ring or wheel be carried round with it and hence the ring
or wheel is moved round a step longer or shorter as may be required. When the return
motion of the lever commences the dogs separate and release the flange and a spring
then draws back that end of the lever upon which the dogs are mounted, the ring or
wheel meanwhile remaining stationary. The dogs being moveable upon studs upon
the nipping lever operate very much more efficiently than nipping projections forming
part of the lever which have before been employed; they greatly extend the area of
effective nipping surface and thereby wear lessened and slipping is prevented.
When the apparatus is applied to a sewing machine, the outer periphery of the
ring or wheel is generally roughened and the work made to rest upon it so that the
work may be carried forward intermittently as the ring rotates in the manner well
known as wheel feed machines.
In place of the two dogs being on opposite sides of a cylindrical flange they
might be set in opposite directions in a cylindrical groove.
Or similarly if a straight movement is to be imparted or prevented the two dogs
may be one on either side of a straight rib or placed in opposite directions in a straight
groove.
For preventing the cages of hoists from dropping in case of breakage or severing
of the lifting rope similar nipping levers carrying moveable dogs may be mounted
upon the cage to grip and hold on to one of the fixed guides or on to a fixed bar
should the rope fail. The apparatus may be used in duplicate with the pivot of the
lever arm of one pair of dogs on one side of the fixed bar and the other on the
opposite side. The weight of the cage hanging on the lifting rope may be made to
keep the levers out of action so long as the rope remains intact so that the cage may
be raised or lowered freely and springs may be used to instantly turn the levers into
position for the dogs to hold on to the bar and prevent the cage from dropping
whenever the rope fails.
Similar nipping levers carrying moveable dogs and acting in the above manner
may also be used for controlling the raising and lowering of window sashes, shutters,
blinds, etc. They may also be used as a means in conjunction with a handle, treadle
or other similar device of communicating motion to bicycles, tricycles, sewing
machines and other machines or vehicles similarly driven.
At Figure 1 of the drawings annexed I have shewn my invention applied for
giving an intermittent revolving motion to the disc or wheel of a button hole sewing
machine of that class in which the work to be sewn is carried by a plate which has
the requisite motions imparted to it from an intermittently revolving disc.
A is the disc with a central hole formed through it within which the circular shuttle
race and shuttle are usually located. A' is a flange standing out from the disc all
around the central hole. B is the lever bent so as not to pass directly across the
hole in order that it may be out of the way of the shuttle race. CC are two studs
carried by one end of the lever-they each have mounted loosely upon them a dog or
nipping instrument D one on one side of the rim and the other on the opposite side.
When the opposite end of the lever is moved in the direction shewn by the arrow
the studs C are both made to approach the flange A and the dogs D which they
carry are consequently caused to grip the flange and the disc is rotated a distance.
When the lever is moved in the opposite direction by a spring or otherwise the dogs
release their hold and the lever can be moved back to its former position.
At figure 21 have shewn the dogs adapted to press against opposite sides of a
groove instead of the dogs being adapted to nip a projecting flange.
At figure 3 I have shewn nipping levers similarly provided with loose nipping dogs
adapted for giving or preventing motion in a straight line. The arrangement shewn
is especially applicable for preventing the fall of the cage of a hoist in case the lifting
rope should break.
A is one of the fixed guide bars of the hoist B B are two levers capable of turning

page_text: and sliding on fulcrum pins E E fixed to the cage on opposite sides of the bar A.
D D are the two nipping dogs carried by each lever one dog on one side of the bar A
and the other on the opposite side. CC are the studs upon which the dogs turn. Fis
a link coupled by pins & to both levers. H is an eye at the lower end of the link to
which the lifting rope may be attached. The lifting rope is arranged to draw the
link downwards either by being passed over a guide pulley carried by the cage or in
other suitable way and when the weight of the cage is being sustained by the rope
the levers are both brought into the position shewn in the drawings but should the
rope break the levers are both drawn upwards by a spring attached to the eyeik at
the top of the link, and the nipping dogs are so brought into action and made to nip
the bar A-the cage then remains suspended upon the fulcrum pins E and its weight
causes the dogs to tighten their hold upon the bar.
Levers carrying loose nipping dogs similarly adapted to grasp a bar or flange or
lock themselves within a groove may as before stated be applied to a great variety of
purposes either for imparting a continuous or intermittent movement as also they may
be adapted for preventing back movement.
For imparting a rotating movement to a disc or wheel they may be worked from
treadles and be moved through either a large or small are as may be required and are
well adapted for giving movement to the driving wheels of bicycles, tricycles and
such like.
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
1. In clutch mechanism for driving or for preventing back movement the use of an
arm having two loose dogs pivoted to it which come on opposite sides of a bar or
flange on the part to be held and driven or to be held only and which are made to
grasp it when the arm is moved in such a manner as to bring the fulcrums of the
dogs nearer to the bar or flange or to release it when the arm is moved in a direction
to increase the distance between the fulcrums and the bar or flange substantially as
described.
2. The modification of the clutch mechanism in which the pivoted dogs are made to
take hold of the opposite sides of a groove.
Dated this 15th day of November 1907
CARPMAEL & Co.,
Agents for the Applicant.