An Improvement in Crank Handles.
Year: 1899

page_text: 1, JAMES HOLMAN, of 79, Great Portland Street, London, W., Engineer, do
hereby declare the nature of this invention to be as follows:--
This invention relates to crank handles such as are used for hand winches,
manually driven cranes, pumps, and other similarly actuated machines, and the
invention has for object to facilitate the driving of such machines by obviating
the opposing manual strains of two or more operators actuating the same crank
handle.
The invention consists in dividing the rotatable slceve in which the crank is
as usual encased, into two or more lengths, capable of independent rotation
about the crank, so that each operator, by grasping a separate sleeve or sleeves
is enabled to apply his power to the best advantage, his wrist or wrists having
freedom to so flex as to accommodate themselves to his own movements, without
such constraint (and consequent less due to opposing muscular exertion) as is
generally experienced where two or more operators grasp the same sleeve.
Dated this 24th day of February 1899
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
An Improvement in Crank Handles.
I, JAMES HOLMAN, of 79, Great Portland Street, London, W., 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:-
This invention relates to crank handles such as are employed in connection
with hand winches, manually driven cranes, divers' air pumps, and other similarly
actuated machines, and the invention has for object to facilitate the driving
of such machines by obviating the opposing manual strains set up when two er
more operators simultaneously actuate the same crank handle.
Crank handles as usually constructed are encased in a rotatable sleeve adapted
to be grasped by the operator so as to allow the crank to revolve freely within the
hand without injury to the latter. The sleeve, even when only one man is driving
the crank, does not maintain the same angular position relatively to its own
axis throughout the entire revolution of the crank, but has a periodic movement
of oscillation about its axis in conformity with the bending movements of the
wrist of the operator. When (say) two men are driving the same crank, the

page_text: flexure of their wrists in either direction may not occur synchronously or have
the same angular amplitude in the case of both, and in such case the tendency
of the sleeve to oscillate in either direction in obedience to the wrist movements
of the one operator will be so opposed by the efforts of the other as to throw on
the wrists of both a strain sufficient to seriously diminish the amount of useful
work performed. The loss of efficiency thus caused is noticeable even when men
(particularly if of different height or muscular strength) work on the same crank
side by side, and is very conspicuous when as usually happens the workmen face
each other from opposite sides of the crank, as in the latter case the wrist move-
ments of the different operators are in opposite angular directions.
These disadvantages are overcome by the present invention, which consists in
providing the crank handle with a rotatable sleeve divided into two or more
separate lengths according to the number of hands which the crank is designed
to accommodate, each portion of the sleeve being capable of independent rotation
about its axis, so as to be free to oscillate without resistance.
The invention is illustrated in the accompanying drawing forming part of
this specification which shews (partly in section) a crank handle adapted to
accommodate three hands, so as to suit the case commonly occurring of two men
working on the same crank, the one-man-using both hands in the forward
direction whilst the other facing the first uses one hand only. a is the crank
shaft, the crank arm, and c the fixed crank pin or spindle. The rotatable
sleeve D is divided in the present instance into three independent sections d¹ d² d³
each composed of a wooden roller or handle e with end ferrules f of metal. The
inner and outer sections are grasped by the operator who for the time-being-
works facing the direction of motion, the middle section being used by the
other operator who faces the first and as usual employs only one hand. The
_section_d_next to the crank arm b is made longer than the others so as to enable
the operator using it to stand clear of the crank arm.-The-sections-of-the
sleeve D are maintained in place by the usual nut g screwing on the end of the
spindle c.
It will be obvious that the number of sections of the sleeve D may be in-
definitely increased according to-the-length of the crank pin c and the number
of men by whom the machine is to be worked; also that the invention may be
readily applied to existing machines with very slight alterations to the sleeves
already in use.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
c
A crank handle provided with a rotatable sleeve divided into lengths each of
which is capable of independent rotation about its axis, substantially as and for
the purpose specified.
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