Improvements in Capstans.
Year: 1887

page_text: Date of Application, 23rd June, 1887:
Complete Left, 23rd Mar., 1888
Complete Accepted, 27th Apr., 1888
Improvements in Capstans.
I, HORATIO FLETCHER, of 5 Sydenham Terrace, Newcastle-upon-Tyne, in the
County of Northumberland, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention has reference to a method of applying springs to capstans, and
means for preventing the slipping of cables on capstans.
In a capstan according to my invention, a spring or springs is or are applied in
such a manner that, instead of the pawls heretofore usually employed dropping into
a ratchet plate fixed down rigidly, the said pawls drop into a ratchet plate that acts
against the said spring or springs which press against an abutment rigidly fixed down,
so that any sudden strain coming upon a cable on the capstan will be relieved by the
play of the said spring or springs. Or there may be used with or without the said
pawls a stop bar arranged to act against a projection or projections on the ratchet plate.
To prevent the slipping of the cable, the capstan is provided with two jaws arranged
to hold the cable between them, and furnished with a screw, or other suitable
mechanical device, whereby the jaws can be moved nearer together or farther
apart.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.

page_text: instead of arranging the spring or springs circularly as shown, it or they may be
spirally arranged or be arranged to work in a straight line, or tangentially or in any
other suitable manner, provided it or they serve to relieve sudden strains on the rope
or cable. Also, in lieu of using spiral springs, metal springs of other forms, or
springs of other suitable material such as india-rubber, suitably arranged to be
directly acted upon by the plate 4 may be employed. In some cases the pawls may
be dispensed with, and in lieu thereof one or more stop bars or sliding bolts, of which
one is shown at 13, may be employed for holding the capstan barrel in position when
required Each bar or bolt 13 may be arranged to slide transversely in a slot 14 in
the plate 4, by means of a lever 15 pivotted to the said plate at 16 and operated by a
hand lever 17; it is adapted to take against one or other of a series of shoulders or
abutments 18 which may be formed by making a series of recesses 19 in the bottom
of the capstan barrel. 17* is a pin or stop for holding the hand lever 17 and bar or
bolt 13 either in the locked or in the unlocked position. 20 and 21 are the two jaws
of a gripping device carried by the capstan barrel, and adapted to hold or release a
rope or cable A as desired. The jaw 20 is fixed, whilst the jaw 21 is adapted to bo
moved nearer to or further from the jaw 20 by means of a screw threaded bolt 22 as
shown. 23 is a tube or sleeve encircling the upper part of the screw-threaded bolt 22
and provided with a pin or projection 24 arranged to slide in an inclined slot or
cam groove 25 formed in a tubular extension 26 on the top of the capstan barrel.
By raising or lowering the tube or sleeve 23 by means of the pin or projection 24
the jaw 21 may be rapidly moved toward or from the fixed jaw 20, the final closing
movement to grip a rope or cable being effected by turning the bolt 22. The jaw 21
may however, be operated solely by rotating the bolt 22 if desired.
Since the date of my provisional specification I have made further inventions
having reference to windlasses, winches, cranes and hoists, and also to bollards which
are respectively the subject matters of separate applications for Letters Patent made
by me and being respectively No. 15870 dated the 18th day of November, 1887, and
No. 16544 dated the 1st day of December, 1887.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what
I claim is
1. A capstan constructed with a spring or springs adapted to permit of limited
backward movement of the capstan barrel to relieve sudden strain on a rope or cable
wound or secured thereto.
2. In a capstan, the combination of a barrel, a moveable plate, means such as
pawls and notches or a bar and projections for preventing independent rotation of the
barrel in relation to the plate in one direction, and a spring or springs against which
the said plate can act, substantially as hereinbefore described for the purpose
specified.
3. The combination with the barrel of a capstan, of a gripping device comprising
jaws adapted to hold a rope or cable and means for changing the distance apart of
the said jaws so as to cause them to grip or release a rope or cable as required
substantially as herein before described.
4. My improved capstan substantially as hereinbefore described with reference to
and illustrated in Figs. 1 to 4 of the drawings annexed whether pawls such as 8 or a
stop bar or locking bolt such as 13 be employed and also whether or not it be provided
with a gripping device for the rope or cable.
Dated this 21st day of March 1888