IMPROVEMENTS IN DIFFERENTIAL HOISTING MACHINERY
Year: 1885

page_text: We, JAMES CHRISTIE, of Wissahickon, Philadelphia, State of Pennsylvania,
United States of America, Engineer, and PERCIVAL ROBERTS, of N° 261, South
Fourth Street, in said Philadelphia, Iron Manufacturer, do hereby declare the
nature of our Invention for "IMPROVEMENTS IN DIFFERENTIAL HOISTING MACHINERY,"
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 certain improvements in the construction of differential
hoisting machinery as described and claimed hereinafter.
On the accompanying drawings :-
-
Fig; 1, represents a vertical section, parts being in elevation, of the improved
hoist.
e
•
Fig; 2. a section on the line 1-2, Fig; 1.
Fig; 3, a plan view of Fig; 1.
Fig; 4, shows the parts of the frame detached from each other,
Fig; 5. represents a sectional view of a modified form,
Fig; 6, a transverse section on the line 3-4. Fig; 5.
Fig; 7. a transverse section on the line 5-6. Fig ; 5.
Fig; 8, a perspective view of the cam shaft and pinions detached,
Figs; 9, and 10, represent views of a further modification.
The frame of the block consists of the two steel castings, A, A¹, the construction
of which will be hereinafter more particularly described.
A portion, m, of the shaft, G, is an eccentric, on which are two cog wheels, H,
and, I, cast in one piece, the latter wheel being larger in diameter and having more
teeth than the former. The teeth of the wheel, I, gear into those of an internal
wheel, n, forming part of the casting, A¹, and the teeth of the wheel, H, gear into
those of an internal wheel, n¹, forming part of a chain drum, M.
The shaft, G, bas one bearing in a projection, e, of the casting, A¹, the other
bearing being in the chain drum, M, and the hub, i, of the latter having its
bearing in the hub, e, of the casting A; this hub, e, projects into an annular
recess, ', in the chain drum, M, in order to relieve the shaft, G, from the strain of
the load, the hub, e, projecting as much as possible under the centre of the drum, M.
It is preferred to use anti-friction rollers in this bearing in the construction of
heavy hoists.

page_text: A chain pulley, N, of large diameter is secured to the shaft, G, and round this
pulley passes an endless chain, by manipulating which the shaft may be turned
and the chain drum, M, rotated through the medium of the gearing described, the
wheels, H, and, I, being also loose on the shaft.
The manner in which the gearing operates to rotate the drum, M, at a much less
speed than the shaft, and consequently causes the pulley to act on the hoisting
chain, Y, with much more power than that exerted to drive the shaft, will be
understood by those skilled in the art, as the system of differential gearing
constitutes a well known mechanical movement which has heretofore been applied
to many different mechanisms, and among others, hoists.
The casting, A, includes the top, w, and side flanges, g, the other casting, A¹, of
the frame consisting of the circular plate shown most clearly in Fig; 4.
These castings are secured to each other by ordinary screw bolts, t, passing
through a lug, 8, on the casting, A', and into a threaded opening in the top, w, of
the casting, A.
The flanges, g, which form part of the casting, Figs; 2, and, 4; while adding to
the strength of this part of the frame, serve as a hood for maintaining the chain, Y,
in its proper position on the drum, N.
It is advisable that the hoist should be at liberty to be moved independently of
the hook, E, to and fro in the direction pointed out by the arrows in Fig; 2, and
for this reason, the opening, h, made in the top of the frame for the shank of the
hook, is elongated and a concave socket, u, is made in the underside of the top of
the frame for the convex portion of the nut, F, which is screwed and rivetted to
the shank of the hook. The said opening, h, should also be wide enough to permit
the hoist to have a limited play laterally, independently of the hook.
It will be seen that the chain drum, M, and the internally toothed wheel, n¹, are
in one casting, the edge of this wheel being overlapped by the edge of the internally
'toothed wheel, n, forming part of the casting, A', all the gearing being thus
shielded.
Another feature contributing to simplicity of construction, is the extension of
the hub, i, of the chain drum, M, into the plate, A, so as to have its bearing therein,
the chain drum and its hub being thus converted into a bearing for the shaft.
Referring to Figs; 5, 6, 7, and 8; the frame.consists of the end plates, A, A¹, and
the top piece, A2, all being, preferably, steel castings, and being secured together by
bolts, a, passing through both plates, A, and, A', and through tubular portions, y,
of the casting, A2, and to the top, w, of the said casting, is swivelled the stem of a
hook, E, as shown in Figs; 1, 2, 5 and 6.
An annular recess, k, is formed in the wheel, I, and small passages connect this
recess with the Bearing of the eccentric. A suitable hole, l, is made in the
casting, A¹, through which'oil is inserted into the recess, k, which is made tapered
towards its rear end in order to hold a small quantity of oil and direct it into the
passages to the bearing..
Referring to the modifications shown in Figs; 9, and 10; the improved hoist is
adapted to a base plate, A³, the bearing, e, being in side plates, A, A¹, secured to or
forming part of the base, A³. The differential gear is the same as in Fig; 1, with
the exception that the wheel, n, in this case is secured to the plate, A¹, by a pin, c,
the hub of the wheel having its bearings in the plate, A¹; the object being to
detach it at times from the plate, A¹, and have it under the control of a brake,
which, as shown in Fig; 10, consists of two levers, K, K, pivotted to the plate, A³,
and connected together by a right and left hand screw, J, having a suitable
handle.
The object of the use of a loose wheel, n, as shown in Figs; 9, and, 10; is to
hold the wheel when raising or lowering the load, and when the chain is relieved
of the load to return it quickly by releasing the wheel from the control of the
brakes, K, K.
:
When the pin, c, is inserted into the hole in the wheel, n, the gear works the
same on in 1

page_text: Having now particularly described and ascertained the nature and objects
of our said Invention and in what manner the same is to be performed; we declare
that what we claim is
1. The combination, in a hoist, of differential gearing, substantially as herein-
before described, with frames consisting of a casting, A¹, and casting, A, the latter
including the top, w, and side flanges, g, substantially as set forth.
2. The combination of the frame of a hoist, its concave socket and the clongated
opening, h, with the hook and its concave nut adapted to the socket, substantially
as described,
3. The combination of the chain drum, M, of the differential gearing, with
castings, A, A¹, and the flanges, g, which are parts of the casting, A, and form a
hood for the said chain wheel, substantially as set forth.
4. The combination, in a hoisting gear, of the shaft, G, bearing, e, and chain
drum, M, the bearing extending into an annular recess in the chain drum as set
forth.
5. The combination, in a hoist, of differential gearing, substantially as described,
with the frame, consisting of the plates, A, A¹, and top piece, A², constructed and
secured to each other, substantially as set forth.
6. The combination of the frame, consisting of the plates, A, and, A¹, and top
piece, A2, with the differential gearing, the chain drum, M, of which has a hub
bearing in the plate, A, and with the shaft, G, extending through and having a
bearing in the said chain drum, substantially as specified.
7. The combination, in a hoist, of the hereinbefore described differential gear, in
which the wheels, H, and, I, are combined with and contained within the internally
toothed wheels, n, n¹, the edge of one wheel overlapping that of the other, as set
forth.
8. The combination, in a hoist, of the hereinbefore described differential gear, the
wheel, I, forming part of the said gear and having an annular recess, k, as and for
the purpose set forth.
9. The combination, in a hoist, of the hereinbefore described differential gear,
wheels, n, n', the wheel, n, being loose in the bearings, and a device for arresting
the wheel, n, all substantially as set forth.
10. The combination, in a hoist, of the hereinbefore described differential gear,
the wheels, n, n¹, forming part of the gear, and braking mechanism applied to the
flange of the wheel, 22, substantially as specified.
11. The combination, in a hoist, of the plate, A¹, and the herein before described
differential gear, the wheel, n, forming part of said gear and loose in the bearing, e,
with a locking pin, c, as set forth.