IMPROVEMENTS IN CRABS FOR RAISING AND LOWERING HEAVY BODIES
Year: 1885

page_text: I GEORGE CROYDON MARKS of N° 8 Richmond Road Handsworth in the
County of Stafford Mechanical Draughtsman do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN CRABS FOR RAISING AND LOWERING HEAVY
BODIES " to be as follows:-
The said crabs as ordinarily made consist of parts the more important of which
are rigidly connected together and in consequence the said crabs occupy as much
space in transit and in storage as when in use.
The object of my invention is to construct the said crabs in such a way that
their more important parts can be readily taken apart and packed in a small
compass for transit and storage and can be readily and firmly connected together
when required.
In making a crab according to my invention I dispense with the keys or key
ways and pins or cotters by which the barrel brake wheel spur wheel and ratchet
are ordinarily fixed to the main shaft of the crab and I mount the barrel brake
wheel spur wheel and ratchet on the main shaft so that they are free to turn
thereon.
I make the barrel brake wheel and ratchet of one casting and the spur wheel
of a separate casting and I connect these two parts together by means of projections
on a flange on that end of the barrel presented to the spur wheel. I prefer to
make these projections of such a size and shape that they fit between the arins or
spokes of the spur wheel This arrangement may however be reversed that is lugs
or projections on the boss of the spur wheel may take into corresponding recesses
in the flange on the end of the barrel.
When the spur wheel and the casting constituting the barrel brake wheel and
ratchet are placed on the main shaft and engaged together in the way described
they constitute virtually one piece and can only rotate together. When the parts
of the framing of the crab are connected together by the ordinary screw bolts and
nuts the two parts engaged together as described are incapable of separating.

page_text: By separating the parts of the framing the engaged parts are liberated and may
be packed in a small compass.
The combined brake and ratchet levers for which provisional protection was
granted to me on the Fourteenth day of August 1884 N° 11,268 may be con-
veniently used with crabs constructed according to my present invention.
W. T. WHITEMAN,
Agent for the Applicant.
Improvements in Crabs for Raising and Lowering Heavy
Bodies.
I GEORGE CROYDON MARKS of N° 8 Richmond Road Handsworth in the
County of Stafford, Mechanical Draughtsman, do hereby declare the nature of my
Invention for "IMPROVEMENTS IN CRABS FOR RAISING AND LOWERING HEAVY
BODIES and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
"
The said crabs as ordinarily made consist of parts the more important of which
are rigidly connected together and in consequence the said crabs occupy as much
space in transit and in storage as when in use.
The object of my invention is to construct the said crabs in such a way that
their more important parts can be readily taken apart and packed in a small
compass for transit and storage and can be readily and firmly connected together
when required.
In making a crab according to my invention, I dispense with the keys or
keyways and pins or cotters by which the barrel, brake wheel, spur wheel and
ratchet are ordinarily fixed to the main shaft of the crab and I mount the barrel,
brake wheel, spur wheel and ratchet on the main shaft so that they are free to
turn thereon. I make the barrel, brake wheel and ratchet of one casting and the
spur wheel of a separate casting and I connect these two parts together by means
of lugs or projections on a flange on that end of the barrel presented to the
spur wheel.
I prefer to make these lugs or projections of such a size and shape that they fit
between the arms or spokes of the spur wheel. This arrangement may however
be reversed, that is, lugs or projections on the boss of the spur wheel may take
into corresponding recesses in the flange on the end of the barrel.
When the spur wheel and the casting constituting the barrel, brake wheel and
ratchet are placed on the main shaft and engaged together in the way described,

page_text: they constitute virtually one piece and can only rotate together. When the parts
of the framing of the crab are connected together by the ordinary screw bolts and
nuts the two parts engaged together as described are incapable of separating.
By separating the parts of the framing the engaged parts are liberated and may
be packed in a small compass. The combined brake and ratchet levers for which
a patent was granted to me on the 14th day of August 1884 N° 11268 may be
conveniently used with crabs constructed according to my present invention.
Figure 1 of the accompanying Drawing represents in end elevation and Figure 2
in side elevation, partly in longitudinal section, a crab for raising and lowering
heavy bodies constructed according to my invention; Figure 3 represents in
longitudinal section and elevations of opposite ends the combined barrel, brake
wheel and ratchet of the crab drawn to a larger scale.
The same letters of reference indicate the same parts in the several Figures of
the Drawing.
a, a are the two side frames or standards of the crab; b is the barrel; c the
brake wheel and d the ratchet; e is the spur wheel fixed to the barrel and driven
in the ordinary way by the pinion on the hand worked spindle g; h is the main
spindle of the crab on which spindle the barrel b, brake wheel c and ratchet & as
well as the spur wheel e turn freely. The barrel b, brake wheel c and ratchet d
are made in one piece by casting. The spur wheel e is made separately and is
connected to the barrel b in the following manner. On the outer face of the
flange on the end of the barrel b are three equi distant lugs i, i, i which fit
between the arms of the spur wheel e, the hollow boss k of the spur wheel c fitting
into the barrel b as seen in Figure 2, and forms a support or guide for the said
barrel.
Or the projections or lugs i, i, i may be made on the boss of the spur wheel and
take into corresponding recesses in the flange 62 on the end of the barrel b. After
the spur wheel e has been engaged with the barrel b of the combined barrel brake
wheel and ratchet in either of the ways described and placed on the main shaft
the said spur wheel and combined parts constitute virtually one piece as repre-
sented in Figure 2 and can only rotate together. After the spur wheel e and
combined parts b, c, d have been thus engaged together, the two side frames a, a
of the crab are secured together by the ordinary stretchers or tie bolts a², a² and
nuts so that the said spur wheel e and combined parts b, c, d are incapable of
separating as will be understood by reference to the drawing of the complete crab
Figures 1 and 2.
The side frames a, a form the standards, supports or bearings for carrying the
handle shaft and barrel shaft h. In order to pack the parts of the crab in a
small compass for transit or storage the side frames a, a of the crab are disconnected
when the spur wheel e may be separated from the combined barrel b, brake wheel c
and ratchet d. In order to give complete control over the pawl and brake of the
crab the arrangement represented in Figure 1 may be employed. This arrange-
ment is claimed in the patent hereinbefore referred to and constitutes no part of
my present invention.
1, 2 is a lever turning on the pin or centre 13 carried by the fixed frame a.
The short arm 2 of the lever bears upon the ratchet pawl m which turns upon the
pin m³.
The eye of the connection p of the brake strap q is secured to the pin or
centre on the fixed framing and the eye of the other connection p² of the brake
strap is connected to the arm of the lever 1, 12. On raising the handle end of
the lever 1, 2 the short arm is depressed and acting upon the short arm m² of the
ratchet pawl m, m² raises the said ratchet pawl from the ratchet wheel d. The
further movement of the handle end of the lever in the same direction tightens
the brake strap q upon the brake wheel d and the load is thus sustained.
By this arrangement the action of the same lever is first made to raise the pawl
from the ratchet wheel and afterwards to put the brake into action so as to control
the motion of the barrel.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
Combining the barrel, brake wheel and ratchet of crabs for raising and lowering.
heavy bodies, in one piece or casting and the connection therewith and dis-
connection therefrom of a separate spur wheel for gearing with the ordinary
pinion of the crab, the several parts being constructed and combined substantially
as and for the purpose herein before described and illustrated in the accompanying
Drawing.
L
1005