Hoisting Apparatus.
Year: 1897

page_text: Date of Application, 2nd Nov., 1897-Accepted, 4th Dec., 1897.
Hoisting Apparatus.
I, JOHN LIDDLE of 154 St. Vincent Street, in the County of the City of Glasgow,
North Britain, Patent Agent, 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 that general type of hoisting machines, wherein the power
or driving wheel or shaft is geared down to such an extent that very large loads may
be elevated by a winding shaft or drum, by the application of a very small force,
either manually or by steam, electric or other power, to said driving shaft.
The object of iny invention is to produce a machine of this general type, which
shall be absolutely automatic in its braking action, that is to say will not back down
under stress of any load imposed upon the chain or equivalent connection which is wound
upon the load-bearing shaft or drum. At the same time my invention seeks to reduce
the number of parts and accordingly simplify the invention.
Heretofore machines of this kind have either employed a block-and-tackle connec-
tion with the load so that the lifting chain pulls vertically upon the load-bearing
shaft and there is no tendency to unwind, or else when said load-bearing shaft or
drum is employed to wind the chain or equivalent connection upon it, a pawl or dog
is employed to hold the machine against retrograde.
I have discovered that if the load-bearing member, a hollow shaft or drum, be
mounted immediately upon the power shaft while said drum or hollow shaft is back-
geared to said power shaft, I obtain in hoisting apparatus, a construction by which
the weight of the suspended load is always automatically available to produce a
frictional resistance or braking power sufficient to resist the tendency of the load to
reverse or back down the hoisting gear when released from its motive power thereby
holding the load suspended at any point desired without having to use any brake or
other device requiring the special attention and manipulation of the operator.
The construction of my improved hoisting machine will be fully understood upon
reference to the accompanying drawings, in which :
Figure 1 is a plan of a machine embodying my invention.
Figure 2 is a side view of the same.
Figure 3 is a vertical section on a reduced scale taken through the shafts.
A represents a power-shaft which may be mounted in any suitable frame or
support B, B and which may be driven by any suitable means, for example, a wheel C.
The load-bearing member D is mounted directly upon the driving shaft A and in
frictional contact therewith. I have illustrated this member as a common form of
chain wheel which will wind up a chain to one side of which is attached the load.
While not essential to my invention, the shaft A may have an enlargement b, between
its bearings to retain the shaft in place and to afford an enlarged bearing for the
load-bearing member D which has turning bearing directly upon said power-shaft.

page_text: The load-bearing member D is back geared to the power shaft A through the large
gear-wheel E fixed relatively to said member D (for convenience cast integrally with
it), the small gear-wheel H fixed upon a counter-shaft I, which also carries and is
rotated by a large gear-wheel G, which meshes with a small pinion F, keyed to the
power shaft.
From the obvious relations of the parts of this back-gearing it will be readily
understood that when the shaft A is rotated, power applied thereto is multiplied so
largely, at the expense of motion, that a very great winding force is transmitted to
the load-bearing member D, but tendency of said member D to unwind under stress
of any load supported by one side of its chain, will be so reduced in power which it
exerts upon the power-shaft that it will amount to comparatively little.
I find in practice by mounting the member D directly upon and in frictional
contact with the power shaft A which must be turned at a comparatively rapid rate
by the slightest movement of member D, that the friction between these two parts is
in excess of any turning or running down tendency which can be transmitted to shaft A
through the back gearing, and the apparatus becomes instantly and automatically
locked whenever and wherever the turning power is withdrawn from shaft A.
While the device has features which are common to hoisting machines operated by
a system of compounded gearing proportioned to obtain the desired power, speed, &c.,
it has also in accordance with the object of my invention as herein set forth, an
additional feature, heretofore entirely unknown in connection with hoisting gearing,
which feature is the capacity to hold a load suspended at any point desired, without
the assistance of a brake or other separate device for preventing a reversal of the gear
under the influence of the load, as in the ordinarily constructed hoisting apparatus.
Moreover, the weight of the suspended load is automatically made available to
produce this capacity to hold the load suspended as desired.
Further, the frictional resistance made available for braking the power-shaft is obtained
solely by mounting upon the power-shaft the hoisting drum, and is explained by the fact
that the quick moving and most sensitive power shaft has to sustain the whole load
put upon the machine whereby an excessive and abnormal degree of frictional turning
resistance is imposed on the said power shaft and this is much greater than can be
overcome by the reversing tendency of the load being sustained.
While I have shown a particular arrangement of back gearing from the hoisting
arm or wheel to the main power shaft, this particular arrangement as well as many
other details are not essential to my invention as said parts may be substituted by
other details.
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:
In a hoisting machine, the combination of a suitable frame or mounting, a power
shaft having bearing in said frame or mounting, a load-bearing or hoisting member
mounted directly upon and in frictional contact with the power shaft, to one side of
the bearing of said shaft in the frame or mounting, and back gearing substantially as
described making turning connection between the hoisting member and the power
shaft so as to cause said load-bearing or hoisting member to be turned by the power
shaft in either direction, but to cause said hoisting member to automatically
bind the power shaft against rotation and thereby lock itself against retrograde
movement under influence of a load, as explained.
Dated this 1st day of November 1897.
BOTTOMLEY & LIDDLE
154 St. Vincent Street, Glasgow Applicant's Patent Agents.