An Improved Form of Friction Brake for Windlasses, Winches, and Cranes of all Descriptions.
Year: 1888

page_text: Date of Application, 3rd Dec., 1888
Complete Specification Left, 27th Sept., 1889-Accepted, 2nd Nov., 1889
PROVISIONAL SPECIFICATION.
An Improved Form of Friction Brake for Windlasses, Winches,
and Cranes of all Descriptions.
THOMAS GEORGE STEVENS, Esther Villas, Swanscombe, Dartford in the County
of Kent, Engineer, do hereby declare the nature of this invention to be as follows:-
It consists of a metal band (F) lined with wood (W) clasping a disc) (D) lined with
either wood or iron, keyed to the spindle (S) of the winch, windlass, or crane to which
the brake is applied. The band lined with wood has two lugs (L) with two pivot
nuts (P) through which a short shaft (T) passes, upon which is cut a right and a left
hand screw.
The shaft is supported on a bracket (X-B) suitably attached. At the
ends of the shaft. I provide buffers (I) of suitable elastic material to form cushions to
take off the jar when the brake is suddenly brought up. The two screw threads on
the shaft I make of different diameter, so that the one of smaller diameter may be
passed end wise freely through the nut for the larger screw thread. This allows of the screw
shaft being unscrewed and readily separated from both nuts whenever the apparatus
may have to be taken to pieces. In order that the whole strain on-the friction band
may not be borne by the screw spindle, I form the band with a third lug (L') and
pivot nut working free on a fixed shaft; this shaft is fitted to any suitable
bracket (X-B¹) and is provided with buffers (I') of suitable elastic materials at its
ends.
By this method the brake can be instantaneously applied by one-quarter, or less, of
a revolution of the screwshaft, and left, with perfect safety, with any weight hanging
upon the gear; or if desired the chain or rope can be paid out gradually under
perfect control.
When the apparatus is applied to cranes it is unnecessary to use the buffers.
COMPLETE SPECIFICATION.
An Improved Form of Friction Brake for Windlasses, Winches,
and Cranes of all Descriptions.
THOMAS GEORGE STEVENS Esther Villas, Swanscombe Dartford 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, reference being had to the drawings filed with my
provisional specification:
:-
My invention consists of a metal band (F) lined with wood (W) clasping a disc (D)
lined with either wood or iron, keyed to the spindle (S) of the winch, windlass, or
crane to which the brake is applied. The band lined with wood has two lugs (L) with
two pivot nuts (P) through which a short shaft (T) passes, upon which is cut a right
and a left hand screw. The shaft is supported on a bracket (X-B) suitably attached.
At the end of the shaft I provide buffers (I) of suitable elastic material, or spiral
springs, to form cushions to take off the jar when the brake is suddenly brought up.
The two screw-threads on the shaft I make of different diameter so that the one of
smaller diameter may be passed endwise freely through the nut for the larger screw-
thread. This allows of the screw shaft being unscrewed and readily separated from
both nuts whenever the apparatus may have to be taken to pieces.
In order that the whole strain of the friction band may not be borne by the screw
spindle, I form the band with a third lug (L) and pivot nut working free on a fixed
shaft; this shaft is provided with buffers (I) of suitable elastic material, or spiral
springs, at its ends.

page_text: By this method the brake can be instantaneously applied by one-quarter, or less, of
a revolution of the screw shaft, and left with perfect safety with any weight hanging
upon the gear; or if desired the chain or rope can be paid out gradually, under perfect
control.
When the apparatus is applied to cranes it is unnecessary to use the_buffers, or
spiral springs.
Having now particularly described and ascertained the nature of my said inven-
Lion, and in what manner the same is to be performed, I declare that what
I claim is;
1. In friction brakes for windlasses, winches and cranes the method of tightening
the brake by two screw threads on the same shaft of different diameter; which allows
the screw shaft to be unscrewed and readily separated from both ends whenever the
apparatus may have to be taken to pieces.
2. In friction brakes for windlasses, &c. the use of buffers of elastic material, or
spiral springs at the ends of the screw shaft to act as cushions.
3. In friction brakes for windlasses &c., the use of a pivot nut working free on a
fixed shaft; this shaft being provided with buffers or spiral springs at its ends.
Dated this Twenty-seventh day of September 1889.
THOMAS GEORGE STEVENS.