Improvements in Pulley Blocks and Tackle.
Year: 1889

page_text: Date of Application, 7th May, 1889
Complete Specification Left. 7th Feb.. 1890-Accepted. 3rd May. 1890
PROVISIONAL SPECIFICATION.
Improvements in Pulley Blocks and Tackle.
I, HUMPHREY MACFARLANE CHALMERS, of Glenlee, Roseneath, in the County of
Dumbarton, Scotland, do hereby declare the nature of this invention to be as
follows:-
This Invention has for its object to make the ordinary pulley blocks and tackle
retain the load as it is raised or to prevent the rope from unwinding, without having
to retain or make fast the hauling rope at or after each purchase; and whereby the
e not being subjected to wear on one part more than another, tends to economy
nereof.
For this purpose one of the set of sheaves or pulleys is formed or provided with a
rachet wheel, into or against which engages a pawl or detent, so that the said sheave
shall revolve only one way. The said sheave is formed with a zigzag or equivalent
groove round or into which works the hauling rope which by the form of groove bites
or is retained therein and prevented from slipping back.
The blocks are connected together by an endless rope, the lowering part of which
may be attached to bottom block, or otherwise retained as convenient. When the
load has to be lowered or halyard slackened the lowering part of rope is loosened,
thereby giving the necessary slackening.
Dated this 6th day of May 1889.
DAVID F. MASON,
Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Pulley Blocks and Tackle.
I, HUMPHREY MACFARLANE CHALMERS of Glenlee, Roseneath, in the County of
Dumbarton, Scotland, 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 :-
This Invention has for its object to make the ordinary pulley blocks and tackle
retain the load as it is raised or to prevent the rope unwinding without having to
make fast the hauling rope at or after each purchase; and whereby the rope not being
subjected to wear on one part of its length more than another tends to economy
thereof.
I have appended an explanatory sheet of Drawings whereon
Fig. 1 is an elevation of a block constructed according to my Invention with one
side plate removed, and
Fig. 2 an end view of rachet pulley or sheave.
Figs. 3 and 4 illustrate modes of working sets of blocks by an endless rope.
As constructed in accordance with my Invention and for the purpose hereinbefore
set forth the last sheave or pulley c of the set is formed (as shown at Fig. 1) with an
internal ratchet consisting of a projecting part or ring a having teeth b on inner
edge thereof, formed on outer edge of sheave e leaving a recess between said teeth
and hub d of sheave into which recess fits the detent e and spring which said spring
and detent are fitted to the side plate by the pins or studs m n respectively thus
allowing the detent to work into teeth b so that the said sheave shall revolve only one
way as indicated by arrow. It is obvious that an outside ratchet may be formed on
a part of periphery of sheave in lieu of that described. As shown at Fig. 2 the
sheave c is formed with a sinuous groove on its periphery into which works the rope o
Figs. 3 and 4 which by the sinuous form of groove is prevented from slipping back
therein.

page_text: The rope o by which the blocks are connected together is endless the hauling or
purchasing part o¹ of which, being retained by ratchet sheave c may be left loose.
The lowering part o" of rope may in ship or general work be fastened to a catch r
in mast s or other place as shown at Fig. 3, or to either hook u u¹ on top or side of
bottom block as shown at Fig. 4. It is obvious that a chain may be used in heu
of rope.
When the load has to be lowered or halyard slackened, the lowering part o" of
rope is loosened and let out thereby allowing the necessary slackening.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is.
1. In a set of blocks and tackle, the construction or combination with the last
sheave c thereof, of a ratchet device and detent, substantially as and for the purpose
described and shown.
2. The particular combination in the particular manner of a set of blocks the last
sheave c of which is allowed to revolve one way only by a ratchet and detent, with an
endless rope or chain, as hereinbefore set forth and shown.
D
كيم
D. F. MASON,
Glasgow, Patent Agent.