IMPROVEMENTS IN APPARATUS FOR TRANSMITTING POWER AND MOTION IN DIFFERENTIAL PULLEYS AND OTHER HOISTING APPARATUS
Year: 1877

page_text: LETTERS PATENT to John Clayton Mewburn, of 169, Fleet Street, in the City
of London, Patent Agent and Consulting Engineer, for the Invention of
" IMPROVEMENTS IN APPARATUS FOR TRANSMITTING POWER AND MOTION IN
DIFFERENTIAL PULLEYS AND OTHER HOISTING APPARATUS." Communicated
from abroad by Thomas Aldridge Weston, of Stamford, Connecticut, in the
United States of America.
Sealed the 17th July 1877, and dated the 18th January 1877.
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 18th January 1877.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN APPARATUS FOR TRANS-
MITTING POWER AND MOTION IN DIFFERENTIAL PULLEYS AND OTHER HOISTING
APPARATUS." Communicated froin abroad by Thomas Aldridge Weston, of Stam-
ford, Connecticut, in the United States of America.
This Invention relates to transmitting the driving power and motion in dif-
ferential pulleys and other hoisting appliances.
I will describe the same as applied to the differential pulley described in the
Specification of Thomas Aldridge Weston's Letters Patent, dated April 29th, 1859,
No. 1033. Upon one side of the differential sheave I form a deep recess with a
circle of annular teeth around it. In a suitable frame I place this sheave upon a
fixed hollow or tubular shaft, upon which it may turn. Upon the exterior of the
hollow shaft and within the above named recess I fix securely a horn plate or car-
rier extending upwards to form a support or bearing to the inner end of a short sta-
tionary shaft, or countershaft, whose outer end is fixed in the frame of the pulley. This
fixed countershaft carries a double pinion turning thereon, the inner half thereof
gearing or engaging with the annular teeth of the differential sheave, and the outer half
gearing with a pinion fixed upon the end of a central driving shaft turning within
the main or hollow shaft above named. The other end of the central driving shaft
carries a sprocket wheel or other convenient appliance for rotating it. By this im-
proved construction of geared pulley blocks the driving or sprocket wheel and its
shaft are concentric with the differential sheave, and the counter shaft and gearing
Prins Gal

page_text: are compactly located within the frame work, secure from injury, and with large
surfaces for wear.
In applying this Invention to a pulley block or hoist not having a differential
sheave, but having a single one or a winding drum instead thereof, attach to the
sprocket wheel and central driving shaft the safety incline apparatus described in
the Specification of Thomas Aldridge Weston's Letters Patent, dated June 6th,
1868, No. 1867, as also to his aforesaid differential pulley when so constructed that
it would otherwise run down of itself under a suspended load.
In another form of the Invention I dispense with the horn plate and fixed
countershaft, making the countershaft to revolve with the pinions thereon, suitable
journals being made in the frame work.
In another form the double pinion has its outer half replaced by an annular
wheel which gears with and encloses the pinion on the central driving shaft.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Clayton Mewburn in the Great Seal Patent Office on the 18th
July 1877.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN APPARATUS FOR TRANS-
MITTING POWER AND MOTION IN DIFFERENTIAL PULLEYS AND OTHER HOISTING
APPARATUS." Communicated from abroad by Thomas Aldridge Weston, of Stam-
ford, Connecticut, in the United States of America.
This Invention relates to transmitting the driving power and motion in dif-
ferential pulleys and other hoisting appliances.
I will describe the same as applied to the differential pulley described in the
Specification of Thomas Aldridge Weston's Letters Patent, dated April 29th, 1859,
No. 1033. Upon one side of the differential sheave I form a deep recess with a
circle of annular teeth around it. In a suitable frame I place this sheave upon a
fixed hollow or tubular shaft, upon which it may turn. Upon the exterior of the
hollow shaft, and within the above-named recess I fix securely a horn plate or
carrier extending upwards to form a support or bearing to the inner end of a
short stationary shaft or countershaft whose outer end is fixed in the frame of the
pulley. This fixed countershaft carries a double pinion turning thereon, the
inner.half thereof gearing or engaging with the annular teeth of the differential
sheave, and the outer half gearing with a pinion fixed upon the end of a central
driving shaft, turning within the main or hollow shaft above named. The other
end of the central driving shaft carries a sprocket wheel or other convenient
appliance for rotating it. By this improved construction of geared pulley block
the driving or sprocket wheel and its shaft are concentric with the differential
sheave, and the countershaft and gearing are compactly located within the frame
work secure from injury and with large surfaces for wear.
In applying this Invention to a pulley block or hoist not having a differential
sheave, but having a single one or a winding drum instead thereof, I attach to the
sprocket wheel and central driving shaft the safety incline apparatus described in
the Specification of Thomas Aldridge Weston's Letters Patent, dated June 6th,
1868, No. 1867, as also to his aforesaid differential pulley when so constructed that
it would otherwise run down of itself under a suspended load.
In another form of the Invention I dispense with the horn plate and fixed
countershaft, making the countershaft to revolve with the pinions thereon, suitable
journals being made in the frame work.
In another form the double pinion has its outer half replaced by an annular wheel
which gears with and encloses the pinion on the central driving shaft.
Having explained the nature of the Invention, I will now describe the same
with reference to the accompanying Drawings, similar letters of reference indicating
corresponding parts in all the Figures.

page_text: Figure 1 is a full size view in sectional elevation of a 2 ton differential pulley,
such as is described in the Specification of Thomas Aldridge Weston's Letters
Patent, dated April 29th, 1859, No. 1033, constructed according to the present
Invention; and Figure 2 is a detail thereof.
Figure 3 is a half size elevation, partly sectional, of a 5 ton pulley, suchas
described in the Specification of the above-named Letters Patent, and constructed
according to one of the modifications of the present Invention; Figures 4 and 5 are
half size side elevations of the same; Figure 6 is a plan of the same; and Figure 7
an end view of the adjacent parts of the frame of Figure 6.
Figures 4 to 7 also represent in general construction corresponding views of
Figure 1, but not in regard to dimensions.
In Figure 1, A1, A2, are the outer side pieces of the frame, preferably of malleable
cast iron; A3, A4, are the inner side pieces, preferably of wrought iron; B is the
well-known differential sheave turning upon the main shaft C; D is a countershaft
or intermediate shaft supported at one end in the side piece A2, and at its other
end in the horn plate E, shown separately in Figure 2; F is a driving pulley
secured to the shaft G; and G₁ is a solid pinion thereon engaging with the wheel
H; I is a pinion formed in a piece with the wheel H, and engaging with the
annular wheel B¹ formed within the sheave B.
Figures 4 to 7 are external views showing the general construction and arrange-
ment of parts in Figure 1, although they belong primarily to the pulley shewn in
Figure 3. The horn plate E is tightly fitted upon the shaft C, and is further
secured by the screw bolt E¹ to the side pieces A2, A The shaft D is thus well
supported, and its whole length available for the wheel and pinion H, I, to turn
upon. The horn plate E may be extended in arca, as also the chambered side
pieces A2, A4, to accommodate any desired number of intermediate shafts and gear
wheels, retaining always the central position of the driving shaft G. The chambered
or recessed form of the side piece A² serves to cover in and enclose the gearing from
dirt and injury.
In the modification of the Invention shown in Figure 3, the intermediate shaft
D is secured to the gear wheels H, I, and revolves with them, suitable bearings
being formed in the side pieces A2, A4, and the horn plate being then omitted.
In another modification of my Invention I make the wheel H an annular wheel
enclosing the pinion G, and engaging therewith at its lowest side.
The operation, which is obvious from the Drawings, is as follows:-The driving
pulley F is formed to engage with the links of an endless band chain, and thereby
rotatory motion may be imparted to the shaft G, and thence transmitted through
the gear wheels G, H, I, and B', to the differential sheave with a gain of power
due to their respective diameters. The hoisting power is thus augmented without
cumbrous dimensions or undue friction, and other advantages are obtained as else-
where, herein set forth. In the example shown in the Drawings the multiplying
power is about 140 to 1 in Figure 1, and 200 to 1 in Figure 3.
The improved driving gear and framework of the present Invention are obviously
applicable where the hoisting sheave B is a single one, or otherwise formed than in
the accompanying Drawings, and in such case, or where the difference of diameters
in the differential sheave is so great that it runs backward of itself under a load, it
is preferred to combine with the pinion G₁ or the driving pulley F the safety
frictional device represented in Figure 8 of the Drawings annexed to the Specifica-
tion of Thomas Aldridge Weston's Letters Patent, dated June 6th, 1868, No. 1867,
whereby the load is self-checked from running away.
Among the advantages obtained in combination in portable hoists of the class
herein referred to by means of the present Invention, the following are prominent,
viz. Compact form with increased power, convenience in handling, reduced
friction and durability, the toothed gearing being throughout plain spur gear
wheels which with all the shafts have fixed axial centres embraced within the

page_text: circumference of the main hoisting sheave and operated by a driving pulley central
to the said main sheave.
And having now described the nature of the said Invention, and in what manner
the same is to be performed, I declare that I claim,―
First. The combination with a differential pulley such as is described in the
Specification of Thomas Aldridge Weston's Letters Patent, dated 29th April, 1859,
No. 1033, of the improved framework and driving gear, substantially as herein-
before described and represented in the accompanying Drawings.
Second. The combination with a pulley block or portable hoist, the main hoist-
ing sheave or pulley of which is not a differential one, but a plain drum or other-
wise formed, of the improved framework and driving gear, substantially as
herein-before described with reference to the accompanying Drawings.
Third. The combination in a pulley block or portable hoist of the improved frame-
work and driving gear, substantially such as is herein-before described and shown in
the Drawings, with the safety frictional device described in the Specification of
Thomas Aldridge Weston's Letters Patent, dated 6th June, 1868, No. 1867, for the
purpose herein-before explained.
In witness whereof, I the said John Clayton Mewburn, have hereunto set
my hand and seal, this Eighteenth day of July, One thousand eight hundred
and seventy-seven.
J. C. MEWBURN. (L.S.)