Improvements in Frictional Brakes or Holders for Preventing Motion of Machinery, also applicable as a Friction Coupling or Clutch for Machinery.
Year: 1895

page_text: Date of Application, 27th July, 1895
Complete Specification Left, 16th Apr., 1896-Accepted, 23rd May, 1896
PROVISIONAL SPECIFICATION.
Improvements in Frictional Brakes or Holders for Preventing
Motion of Machinery, also applicable as a Friction Coupling
or Clutch for Machinery.
CHARLES HAWKINS of 9 Freelands Road Bromley in the County of Kent
Engineer, do hereby declare the nature of this invention to be as follows:-
"
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My invention has for its object the improvement of what are known as strap"
or "band-brakes so as to greatly increase the holding power and enable them to
hold firmly against very great or excessive strains.
In carrying out this invention I apply to a pulley or drum carried upon a shaft a
brake-strap having one end attached to a rol or screw-nut-or other mechanical
equivalent for pressing or pulling the strap down upon the pulley while the other
end is attached to one end-being the long arm-of a lever which is pivotted in a
block bearing against the face of the pulley. At the other end of this lever being
the short arm where the power or pull of the strap has been augmented by the
leverage I attach two other brake straps laying around the pulley one on each side of
the first brake strap and I fix their other ends finally to the machine framing, if
I consider this first series sufficient for the strain to be dealt with, if not, instead of
making fast the ends to the framing 1 attach them to the long arm of another lever
which is again supported upon the former block-or I may support it upon an
independent block or blocks-then the short arm of this lever is attached to two
other straps laying around the pulley outside the others and their ends finally made
fast to the framing thereby completing a second series-thus I can add series
according to the strains to be dealt with.
Instead of attaching two straps to the end of the short arm of the lever I can if
I choose arrange the lever to one side of the first strap and then only attach one
broader and stronger strap to bear the increased pull of the lever.
When my invention is to be used as a clutch the fixed ends of the straps in the
above described apparatus are carried on a drum surrounding the pulley and I
arrange a lever to tighten and slacken the straps by means of a cam or screw-wheel
so that when tightened the drum and the pulley become frictionally connected and
the motion of the one becomes imparted to the other.
Dated this 26th day of July 1895.
COMPLETE SPECIFICATION.
Improvements in Frictional Brakes or Holders for Preventing
Motion of Machinery, also applicable as a Friction Coupling
or Clutch for Machinery.
I CHARLES HAWKINS of 9 Freelands Road, Bromley in the County of Kent,
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:―
"
My invention has for its object the improvement of what are known as strap"

page_text: or "band" brakes so as to greatly increase the holding power and enable them to
hold firmly against very great or excessive strains.
In carrying out this invention I apply to a pulley or drum carried upon a shaft a
brake band having one end attached to a rod or screw-out or other mechanical
device for pressing or pulling the band down upon the pulley while the other end
is attached to one end of a lever which is pivotted in a block bearing against the
face of the pulley. At the other end of this lever where the power or pull of the
band has been augmented by the leverage I attach two other brake bands laying
around the pulley one on each side of the first brake band,-thus I obtain two turns
around the pulley, one by the central band and once again by the outer double
bands after which I fix their ends finally to the machine framing if I consider this
first series sufficient for the strain to be dealt with, if not, instead of making fast the
ends to the framing I attach them to the arm of another lever which is supported
upon the former block or I may support it upon an independent block then the
other arm of this lever is attached to two other bands laying around the pulley
outside the others and their ends finally made fast to the framing thereby
completing a second series thus I can add series according to the strains to be
dealt with.
In some cases I prefer to joint the end of the central band direct to the two
outside bands without interposing the lever and after the outer bands have passed
around the pulley, then attach their ends to a lever pivotted on the machine
framing and arranged to press all three bands firmly up to the pulley.
When my invention is to be used as a clutch, the fixed ends of the bands in the
above described apparatus are carried on a drum surrounding the pulley and
I arrange a lever to tighten and slacken the bands by means of a cam or screw-
wheel so that when tightened the drum and the pulley become frictionally connected
and the motion of the one becomes imparted to the other.
In order that my invention may be fully understood the annexed sheets of
drawings will more clearly show the manner of carrying it into effect, which I will
proceed to explain, observing that similar parts in the different views have similar
reference letters.
Fig. 1. shows a perspective view of my improved brake as applied to a pulley A.
The central band or strap B passing from the foot lever C over the pulley then
jointed to the lever D which is pivotted in the pressure block E. The end of the
lever D which is nearest towards us is then jointed to two bauds F and F which as
shown, are thrown wide enough apart to pass one on each side of the central band B
over and around the pulley A and their other ends finally made fast at the
brackets G and G. In operating this brake any downward motion of the
footlever C produces a pull upon the central band B which pull is increased by its
own grip of the pulley A which is supposed to be revolving in the direction of the
arrow, the pull is then transferred to the far end of the pressure lever D, which
again augments the pull and pressure through the leverage-say 4 to 1-and
transfers the increased pull onto the ends of the two outer bands F and F causing
them to grip the pulley with enormous force and consequently greatly retarding
effect to the motion of the pulley A. The leverage of D may be any proportion
desired.
Fig. 2. shows an arrangement where in some cases I prefer to joint the central
band B direct to the two outer bands F and F without the interposition of
a lever, the kind of joint being shown in the side view Fig. 3.-and after the outer
bands F and F have passed over the pulley I then attach their_ends to a lever D
which now has the greater pull derived from the double hands. This lever pivotted
at a bracket G I arrange to press agaiust the whole three bands by a linked block
piece H at the joint. This lever I can use in combination with the arrangement of
Fig. 1. attaching it at the ends of the double bands and allowing it to press against
the block E or underside of the former lever and pivotting it in the bracket of the
footlever.
Figs. 4 and 5 are respectively a side and end view of an arrangement whereby

page_text: the brake is made available for operating by hand by means of a hand wheel and
screw which is all supported and carried in a convenient position by the link
pieces I and I.
In other respects the parts are similar to those of Fig. 1. which
description will also serve for this.
Fig. 6. shows my arrangement of friction clutch or coupling. Let it be required
to frictionally connect the shaft J to the shaft K. The pulley A is keyed to J and
the outer drum L which carries and is attached to the brake bands is keyed to K.
The bands are tightened by the handwheel and scroll M by means of the lever C
until sufficient friction is obtained to drive or operate whatever is required through
the drum L and shaft K.
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
1st. The improved band brake consisting of a central band jointed to and
combined with two other bands applied to a pulley or drum as Figs. 1. 2. 3. 4. 5,
the parts being combined and operated substantially in the manner and for the
purposes herein before described.
2nd. The joining a brake band after it has passed around a pulley to two other
bands so that the latter may pass also around the pulley one on each side of the
former so as to make a second turn around the pulley, substantially as shown at
Figs. 2 and 3.
3rd. The use of a lever as D. Figs. 1. 4. 5. for linking and connecting a brake
band after it has passed around a pulley to two other bands so that the latter may
pass also around the pulley one on each side of the former so as to make a second
turn around the pulley, substantially in the manner as shown and for the purpose
described.
4th. The use of a lever for joining brake bands after passing around a pulley to
a fulcrum support or fastening, substantially in the manner shown Fig. 2. and for
the purpose described.
5th. The construction of friction couplings or clutches substantially in the
manner shown Fig. 6.
Dated this 16th day of April 1896.
CHARLES HAWKINS.