IMPROVEMENTS IN HOISTING MACHINERY
Year: 1885

page_text: I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of my invention for "IMPROVEMENTS IN 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 improvements in hoists having a differential movement
caused by gyrating a gear wheel in connection with one or more other gear wheels
having a different number of teeth; and the objects of the improvements are to
provide means for raising heavy weights by the use of small gear wheels and also
to prevent the hoist from running down, when loaded, by means calculated to
produce the least amount of friction.
These objects are attained by the mechanism illustrated in the accompanying
drawing, in which
Figure 1 is a vertical section of the entire mechanism, and
Figure 2 is a vertical section on the line 1-2.
Similar letters refer to similar parts in both figures.
The yoke A, A, is supported by the hook J, and carries a stationary shaft B.
The sprocket wheel D with an eccentric I attached to its hub, revolves freely
upon the shaft B, being driven by the hand chain K.
A double gear wheel H is mounted upon the eccentric I, so that one set of its
teeth engage with a gear wheel G which is firmly secured to the stationary
shaft B, and the other set of teeth with the gear wheel E which carries the lift
chain L.
When power is applied to the wheel D, the eccentric I revolves in the gear
wheel H which thus receives a gyrating or swaying movement, but as the gear
wheel H engages with the stationary gear wheel G it receives, at the same time, a
rotary movement due to the differential number of teeth between it and the gear
wheel G. The gear wheel H also engages with the gear wheel E, imparting to
the latter a rotary motion due to the differential number of teeth between the gear
wheels H and E. By the use of the stationary gear wheel G keyed to the shaft,

page_text: the friction incident to other devices intended to make such a hoist self-sustaining
as regards its load is avoided. When arranged as shown, the gear wheels H and E
have a tendency to rotate in different directions, thus enabling the forward or
lifting movement of the gear wheel E to be made very slow for heavy weights.
The cause of the tendency of the gear wheels H and E to rotate in different
directions will be readily understood from the following explanation, viz:-
Supposing the fixed gear wheel G to have twenty teeth, and the gyrating gear
wheel H which engages with it to have nineteen teeth, it is evident that at each
gyration the gear wheel H would lose one tooth, or move to the left, for instance, &
distance equal to the pitch of one tooth; while if the lifting gear wheel E has
twenty teeth and the gyrating gear wheel H which engages with it has but
nineteen teeth it is evident that at each gyration of the gear wheel H the gear
wheel E would gain one tooth, or move to the right a distance equal to the pitch
of one tooth; but the pitch of the large gear wheel E is greater than the pitch of
the fixed gear wheel G, and as the gear wheel H moves one tooth to the left, and
the gear wheel E one tooth to the right, it is evident that the net gain of the
lifting gear wheel E would be toward the right a distance equal to the difference
in pitch between the gear wheels G and E, which may be made very slight, if
desired.
It will be observed also, that the fixed gear wheel is located between the
lifting gear wheel E and the gyrating gear wheel H, thus securing compactness
and cheapness of construction, and at the same time effectually covering the fixed
gear wheel and protecting it from dust and dirt.
By placing both sets of teeth of the double gear wheel in the same plane, or
on one side of the plate, compactness and cheapness of construction are also
secured,
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to me
by my foreign correspondent I declare that what I claim is
First. A fixed gear wheel G firmly secured to a stationary shaft B, between the
lifting gear wheel E and the gyrating gear wheel H, substantially as, and for the
purpose, set forth.
Second. In a hoisting machine, a fixed gear wheel G keyed to a stationary shaft
passing through its centre, in combination with a double gear wheel H driven by
an eccentric, as, and for the purpose, set forth.
Third. The combination of a stationary gear wheel G, a double gear wheel H
having its teeth in the same plane, a lifting gear wheel E, and an eccentric I,
substantially as, and for the purpose, set forth.
Fourth. In a hoisting machine, a stationary gear wheel G, in combination with
a gyrating gear wheel H, and a lifting gear wheel E arranged with the tendency
to revolve in opposite directions, substantially as, and for the purpose, set forth.
Dated this 12th day of May 1885.
HASELTINE, LAKE & Co.,
For the Applicant.