Improvements in Capstans.
Year: 1889

page_text: Date of Application, 9th Dec., 1889
Complete Specification Left, 9th Sept., 1890-Accepted, 11th Oct., 1890
PROVISIONAL SPECIFICATION.
Improvements in Capstans.
1, WILLIAM HORATIO HARFIELD, of Mansion House Buildings, in the City of
London, Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to double power capstans, that is to say, to that class of capstans
having two speeds, and has for object to render such capstans more efficient than
hitherto as a capstan constructed in accordance with my improvements will give the
usual power and rate of motion of an ordinary capstan when the men at the bars
walk in one direction but if they turn and walk the contrary way my improved
capstan will have twice or thrice the hauling power while the direction of pull
will remain the same, and this change of power is effected automatically without
the necessity of withdrawing a bolt, clutch or catch of any description.
In carrying out my invention I mount upon a vertical spindle fixed or held in
a convenient manner and rising a suitable height an ordinary capstan body, cable-
holder or barrel so as to turn freely upon the spindle. Around the upper part of
the capstan body is formed an internal toothed wheel into which gear two pinions
turning loosely upon studs held in a plate carried on the spindle around which it
is free to turn. Immediately beneath this plate and attached to the spindle is a
plate or disc having a ring of ratchet or inclined teeth formed on its upper surface.
Into these teeth can fall pawls or catches which are carried on the pinion plate so
that in one direction they will take or hold but in the other direction they will
slide or rise over the inclines.
Above these fittings I mount loosely upon the spindle a capstan head having the
usual bar holes and at its centre, and preferably formed in one with it, is a pinion
which gears into the two pinions previously described and forms therewith a train
of wheels for conveying motion from the capstan head to the capstan body or
barrel. Near the periphery of the capstan head I place one or more pawls or
catches which can fall or take into inclined teeth formed on the upper edge of the
capstan hody or barrel close to the teeth of the internal wheel. These pawls, when
the capstan head is moved, catch and drive the body along with it in one direction
while if the head is moved the contrary way the pawls rise over the inclines and
have no effect; but then the centre pinion tends to drive back the plate carrying
the two intermediate pinions until its pawls stop it which act the reverse way to
those in the head so that the intermediate pinions are forced to revolve on their
studs and drive onwards the body into which they are geared at a rate pro-
portionate to the relative sizes of the centre pinion and the large internal wheel.
Dated the 9th day of December 1889.
COMPLETE SPECIFICATION.
Improvements in Capstans.
I, WILLIAM HORATIO HARFIELD, of Mansion House Buildings, in the City of
London, Mechanical 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 relates to double power capstans, that is to say, to that class of
capstans having two speeds, and has for object to render such capstans more efficient

page_text: than hitherto as a capstan constructed in accordance with my improvements will give
the usual power and rate of motion of an ordinary capstan when the men at the bars
walk in one direction but if they turn and walk the contrary way my improved
capstan will have twice or thrice the hauling power while the direction of pull
will remain the same, and this change of power is effected automatically without
the necessity of withdrawing a bolt, clutch or catch of any description.
In carrying out my invention I provide in the interior of the capstan a train of
gearing part of which (two pinions) is carried by a plate capable of rotation around
the capstan spindle and fitted with pawls or catches adapted to engage with teeth
in a plate fixed to the capstan spindle. A pawl or catch is also fitted in the
capstan head and is adapted to engage with teeth in the capstan body formed in
the opposite direction to the teeth of the fixed plate, all as hereinafter more
particularly described.
In order to enable my invention to be fully understood I will describe how it can be
carried into practice by reference to the accompanying drawing, in which.
Figure 1 is a vertical section of a capstan constructed according to my invention.
Figure 2 is a plan of the plate carrying the two pinions.
Figures 3 and 4 are sections shewing portions of the two sets of teeth respectively
with their pawls or catches.
Similar letters in all the figures indicate similar parts.
a represents the spindle of my capstan fixed in a bed plate b which is held firm and
rigid by means of bolts in the usual manner.
The spindle a is of sufficient height to carry an ordinary capstan barrel, body or
cable holder c turning freely upon the spindle a. The train of gearing which I
provide in the interior of the capstan consists of a ring of teeth d formed around
the interior of the upper part of the capstan body c with which teeth gear two
(or more) pinions e, e turning loosely upon studs f, f held in the plate carried
on the capstan spindle a around which it is free to turn. Immediately beneath
the plate g and fixed to the spindle is the plate or disc h having the ring of ratchet
or inclined teeth h¹, Figures 1 and 3, formed on its upper surface. i, i, Figures 1,
2 and 3 are the pawls or catches which are carried by the pinion plate g; these pawls
engage with the inclined teeth ' in the plate h when the plate 9 revolves in one
direction, but slide or ride over the inclined parts of the teeth when the plate g revolves
in the opposite direction.
Above these fittings I mount loosely upon the spindle a the capstan head; having
the usual bar holes ; at its centre, and preferably formed in one with it, is a pinion k
which gears into the two pinions e, e and forms therewith a train of wheels for
conveying motion from the capstan head ; to the capstan body or barrel c, Figure 2;
1, Figures 1 and 4, is the pawl or catch placed in the capstan head j near the periphery
thereof and m, m are the inclined or ratchet teeth into which the pawl or catch falls
or takes and which are formed on the upper edge of the capstan body or barrel c close
to the teeth d. The teeth m are inclined in the opposite direction to the teeth h¹.
The operation is as follows:-
When the capstan head ; is moved by means of the capstan bars in the direction
indicated by the arrow marked 1 in Figure 2, the pawl / will catch in one of the
teeth m and drive the body c, the pinion plate g with its pinions e, e contained within
the capstan revolving therewith around the spindle a but remaining inoperative and
the pawls i, i riding over their teeth A'. The power and rate of motion are in this case
those of an ordinary capstan.
If the capstan head; be moved in the opposite direction as indicated by the arrow
marked 2 in Figure 2 the pawl I will ride over the inclined teeth m and, consequently,
have no effect on the body c but the centre pinion will turn the pinion plate g in the
same direction as shown by the arrow 3 until the pawls i, i sliding down the inclines
of the teeth stop it; the pinions e, e will then be caused to revolve on their studs fif
in the direction of the arrows 4, 4 and, by gearing with. the teeth d, will drive the
capstan body c, at a reduced rate of speed but with an increase of power and in the

page_text: same direction as that first described namely in the direction of the arrow 1 in
Figure 2, the rate being proportionate to the relative sizes of the centre pinion k and
internal ring of teeth d.
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 :-
(1.) A capstan having an interior train of gearing, such as that described, two or
more pinions of which are carried by a piate fitted with pawls which hold or catch in
a contrary direction to a pawl carried in the capstan head, substantially as herein-
before described and illustrated in the accompanying drawing and for the purpose
specified.
(2.) The combination of parts forming the improved capstan arranged and operating
as herein before described and illustrated in the accompanying drawing.
D. J.
LL 1900
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.