Year: 1887

page_text: Date of Application, 24th Sept.. 1887
Complete Left, 8th June, 1888
Complete Accepted, 13th July, 1888
THOMAS PLWELL OF 20 Avenue irutame, raris, France, Engineer, no hereby
leclare the nature of this invention to bo as follows:-
My invention relates to improvements in hoisting and lowering gear whereby the
speed of the load may be varied as desired.
Reference is to be had to the accompanying drawing, which illustrates an example
of the invention.
My invention consists in obtaining the desired variations of speed by means of two
chain wheels or barrels a, a acting either separately, conjointly, or differentially upon
the hoisting chain. The chain wheels a a' respectively gear with the two members or
falls of the chain (which is usually endless, the load being suspended from a
pulley running in the pendent bight of the chain) and when operating conjointly the
wheels run in the same direction and when acting differentially thoy run in opposite
directions, at different speeds. When one wheel only is in operation the other wheel
serves as a fixed point of attachment for the chain. The wheels are actuated each by
a mechanical arrangement capable of maintaining it at rest under the load at any
point of the lift, and for this purpose worm gear would generally answer, but any
other mode of transmission may be employed, according to circumstances.
As an example of the series of spoeds which may be obtained by the separate,
combined or differential action of the two chain wheels working independently at
different speeds, let it be supposed that by the roiation of chain wheel a alone the
chain can be operated to raise or lower the load at the rate of 3 feet per minute,
and by the rotation of wheel a' alone it can be raised or lowered at the rate of 1 foot
per minute. Then designating the hoisting motion of the load by the sign + and
the lowering motion by the sign the following series of eight different motions
will be obtained
+3 feet per minute, wheel a
גן
د,
-
3 feet
+ 1 foot
wheel a¹
"
23
1 foot
+4 feet
4 feet
-
+ 3 feet
-
"
22
turning alone in the direction for hoisting
in the direction for lowering
in the direction for hoisting
in the direction for lowering
23
"
wheels a a' turning together in the direction for hoisting
in the direction for lowering
3)
1 foot = +2 feet wheel a turning in the direction for hoisting
and wheel a turning in the direction for lowering
- 3 feet +1 foot
-
-
2 feet wheel a
and wheel
11
"
for lowering
for hoisting

page_text: To facilitate explanation it is assumed that the speeds for hoisting and lowering
were equal for each of the wheels, but it will be evident that these speeds may be
different and also that each wheel may have several different speeds for raising and
lowering, and that in this manner numerous combinations of speeds both for raising
and lowering may be obtained.
The lifting chain may be of any suitable kind and may be arranged as a single,
double, or multiple purchase tackle.
The arrangement of the endless chain as well as of the mechanism for operating the
two chain wheels may be varied without departing from the invention which consists
broadly in actuating the two members of the chain by two independent chain wheels.
The invention may be employed in connection with all kinds of apparatus for hoisting
and lowering loads, such as cranes, travellers, and the like.
Dated this 24th day of September 1887.
T. ELWELL.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: 1. THOMAS ELWELL of 26 Avenue Trudaine, Paris, France, 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 :-
My invention relates to improvements in hoisting and lowering gear, whereby the
speed of the load may be varied as desired.
Reference is to be had to the drawing accompanying my provisional specification,
which illustrates an example of the invention.
My invention consists in obtaining the desired variations of speed by means of two
chain wheels or barrels a a³, acting either separately, conjointly, or differentially upon
the hoisting chain. The chain wheels a a' respectively gear with the two members or
falls bb of the chain c (which is usually endless, the load being suspended from a
pulley running in the pendent bight of the chain) and when operating conjointly the
wheels run in the same direction, and when acting differentially they run in opposite
directions at different speeds. When one wheel only is in operation the other wheel
serves as a fixed point of attachment for the chain. The wheels are actuated each by
a mechanical arrangement capable of maintaining it at rest under the load at any
point of the lift, and for this purpose worm gear would generally answer, but any
other mode of transmission may be employed, according to circumstances.
As an example of the series of speeds which may be obtained by the separate,
combined, or differential action of the two chain wheels working independently at
different speeds, let it be supposed that by the rotation of chain wheel a alone, the
chain can be operated to raise or lower the load at the rate of 3 feet per minute,
and by the rotation of wheel a' alone it can be raised or lowered at the rate of 1 foot
per minute. Then designating the hoisting motion of the load by the sign + and the
lowering motion by the sign, the following series of eight different motions will be
obtained
+3 feet per minute, wheel a turning alone
دو
- 3 feet
22
+ 1 foot
"
wheel a¹
1 foot
+ 4 feet
-
4 feet
+ 3 feet
-
22
"
"
"
in the direction for hoisting
"
"2
"
"
lowering
hoisting
lowering
wheels a a¹ turning together in the direction for hoisting
turning together in the direction for lowering
1 foot feet wheel a turning in the direction for hoisting
and wheel a turning in the direction for lowering
- 3 feet + 1 foot
-
-
2 feet wheel a
"
"
"
and wheel a¹
"
33
"1
lowering
hoisting.

page_text: different and also that each wheel may have several different speeds for raising and
lowering, and that in this manner numerous combinations of speeds both for raising
and lowering may be obtained.
The lifting chain may be of any suitable kind and may be arranged as a single,
double, or multiple purchase tackle.
The arrangement of the endless chain as well as of the mechanism for operating
the two chain wheels may be varied without departing from the invention which
consists broadly in actuating the two members of the chain by two independent
chain wheels. The invention may be employed in connection with all kinds of
apparatus for hoisting and lowering loads, such as cranes, travellers and the like.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
The herein described means of operating the hoisting and lowering chain of all
kinds of hoisting apparatus, at different speeds, the said means consisting in operating
the two members or falls of the chain by two independent chain wheels or barrels
having different speeds and acting separately, or conjointly, or differentially upon the
hoisting and lowering chain and capable of being rotated in the one or other direction
at will, substantially as herein specified.
T. ELWELL.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.