IMPROVEMENTS IN BLOCKS FOR HOISTING
Year: 1861

page_text: LETTERS PATENT to Watson Duchemin, of Charlottetown, Prince Edward's
Island, for the Invention of "IMPROVEMENTS IN BLOCKS FOR HOISTING."
Sealed the 16th April 1862, and dated the 3rd December 1861.
PROVISIONAL SPECIFICATION left by the said Watson Duchemin at the
Office of the Commissioners of Patents, with his Petition, on the 3rd
December 1861.
I, WATSON DUCHEMIN, of Charlottetown, Prince Edward's _Island, do
hereby declare the nature of the Invention for "IMPROVEMENTS IN BLOCKS
FOR HOISTING," to be as follows:-
My Invention relates to improvements in that class of hoisting blocks in
which friction rolls are introduced, and consists, firstly, in a block having a
ring or central bearing of considerable diameter cast on to or otherwise
suitably attached to the shell of the block, and surrounded by a loose metal
ring (which serves the purpose of the sheave of an ordinary block), and between.
which and the central bearing is interposed a series of friction rolls, on which
the loose ring turns. The block is, by preference, made of brass or malleable
iron, the shell being divided into two halves, which are held together by bolts
and nuts. One half, of the block is furnished at one end with a hook, and at
the other with an eye or becket; the other half forms the cap plate, and is of
less thickness at its ends where the bolts pass through it. Both parts have a
circular opening through the centre. From the inner face of the half having
the eye attached to it rises a stout ring, the outer edge of which is embraced by
the cap plate; exterior to this ring grooves are formed on the inner face of the

page_text: plates forming each of the halves, thus forming rings which project up from
the face of each plate. A heavy loose ring is placed between the two plates;
it is turned out around its circumference to receive the rope, like an ordinary
sheave, and has a rib on its inner side, which fits between two of the rings;
the loose ring is of a somewhat larger diameter than these rings, and revolves
freely outside of them. Between the loose ring and the stationary ring, which
projects, as above stated, from one of the plates, are placed friction rolls of a
greater diameter than the width of the grooves in the plates, so that they rest
on the rings and fill the space between the loose and fixed rings, the loose
ring rolling around on these friction rolls. To prevent these friction rolls from
rolling in contact with each other, and grinding together, another series of rolls,
of less diameter but of greater length, is introduced, one between each roll;
these smaller rolls lie in the grooves in the plates, and revolve freely therein.
Instead of small rolls I sometimes employ blocks, which are curved out on
each side to match the friction rolls, and are introduced between the rolls to
keep them separate, but are not intended to receive the bearing of the lower
ring, unless a weight should be applied to the ring sufficient to crush the
friction rolls, or to indent them into the ring. Before this, however, can take
place to any considerable degree, the loose ring will be supported by the
blocks (when these are used), or by the rings in the plates. Any required
degree of strength may be given to the fixed ring, whilst the form of the
shell with the opening in the centre allows the block to be made light in pro-
portion to its power and strength. Or in some cases, where lightness is not
so much an object, the shell may be made whole, that is, without any opening,
and instead of the fixed ring a solid disc may occupy the centre of the block;
and serve as a bearing for the friction rolls.
The second part of my Invention consists in improvements in metal
bushings for sheaves of blocks, the same consisting of a loose ring or sleeve
surrounding the axle on which the sheave runs, a series of friction rolls,
and a box for containing the same. The box is, by preference, of brass or
other suitable metal, and is let into the sheave, and secured in place by screws
-or-rivets-passing-through-its-rim.-A-cap-closes-the-other-side-of-the-box, and
is secured by pins or screws passing through the side of the box into the edge
of the cap; the pin or axle on which the sheave revolves passes through and
fits in the, strap, and is. secured by means of a nut. A sleeve is -introduced
into the bushing through which the pin or axle passes, and which turns on
this pin; it is turned down at each end where it passes through the face of
the box, which is let into the sheave and through the cap, leaving a larger
portion in its middle, which prevents its working out endwise. Between the

page_text: sleeve and the box is introduced a series of friction rolls on which the sleeve
rolls, and a series of blocks, one of which is placed between each of the
friction rolls, to keep them apart, and prevent their grinding one on the
other. These blocks are of the same length as the rolls, but their depth is
rather less than the diameter of the rolls, so that the sleeves shall bear on the
rolls. The circle of friction rolls is thus increased in size by the thickness of
the sleeve, which causes the rolls to operate more freely than they would in.ȧ
smaller circle, and if from any great or sudden strain. the rolls should be
crushed and ceased to operate, the pin or axle will turn freely in the sleeve, and
the block will be as efficient and run as easily as an ordinary block: This
construction of the bushing also has another advantage, that when a weight
is suspended on the block the axle or pin cannot lie between any two of the
friction rolls and force them apart, as is liable to be the case in some other
blocks, in which friction rolls are used, and in which the pivots of the rolls
are often broken in this manner. Instead of the blocks between the friction
rolls, smaller intermediate rolls may, be introduced, one between each roll,
in which case the smaller rolls will run in grooves formed for the purpose in
the box and cap!
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Watson Duchemin in the Great Seal Patent Office on the
3rd June 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WATSON
DUCHEMIN, of Charlottetown, Prince Edward's Island, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent; bearing date the Third day of December, in the year of our Lord
1861, in the twenty-fifth year of Her reign, did, for Herself, Her heirs
and successors, give and grant unto me, the said Watson Duchemin, Her
special licence that I, the said Watson Duchemin, my executors, adminis-
trators, and assigns, or such others as I, the said Watson Duchemin, my
executors,, administrators, and assigns, should at any time agree with, and
no. others,. from time to time and at all times thereafter, during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
BLOCKS FOR HOISTING," upon the condition (amongst others) that I, the-
said Watson Duchemin, my executors or administrators, by an instru-

page_text: ment in writing under my, or their, or one of their hands and seals, should
particularly describe, and ascertain the nature of the said Invention, and 'in
what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months.next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Watson Duchemin, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the Drawings hereunto annexed, and
to the letters and figures marked thereon (that is to say):-
Fig. 1 is a plan of a block, one side of the shell being removed:; Fig. 2, a
section through the same on the line x, x, of Fig. 1; Fig. 3, detail to be
referred to; Fig. 4, a plan of a block, with part of the shell removed, showing
my improved bushing for the sheaves of blocks; Fig. 5, a section. through
the middle of the block on the line y, y, of Fig. 4.
My present Invention relates to improvements in that class of hoisting
blocks in which friction rolls are introduced, and consists, firstly, in á
block having a ring or central bearing of considerable diameter cast: on to or
otherwise suitably attached to the shell of the block, and surrounded by a loose
metal ring (which serves the purpose of the sheave of an ordinary block), and
between which and the central bearing is interposed à series of friction rolls on
which the loose ring turns. Secondly, in improvements in metal bushings for
sheaves of blocks, the same consisting of a loose ring or sleeve surrounding
the axle on which the sheave runs, a series of friction rolls, and a box for con-
taining the same.
That others skilled in the art may understand my Invention, I will
proceed to describe the manner in which I have carried it out.
or becket d';
In the said Drawings, Fig. 1 represents a block (which I prefer to have
made of brass or of malleable iron) the shell of which is divided into two
halves A, A, which are held together by bolts a and nuts b. The block is
furnished at one end with a hook c, and at the other with an eye
these are formed on the half A' of the shell shown in Fig. 1, the cap plate A
being of less thickness at its ends where the bolts a pass through it. Both parts
have a circular opening B through the centre. From the inner face of the
piece. A rises a stout ring e, the outer edge 3 of which is embraced by the
cap plate A. There is formed in the face of each plate A, A, grooves f, g,
exterior to the ring e, forming rings 4, 5, 6, 7, which project up from the face
of each plate. A heavy ring C is placed between the two plates A, A; it is
turned out at h to receive the rope, like an ordinary sheave, and has a rib. on

page_text: '
its inner side, which fits between the rings 4 and 5; this ring C is of a some-
what larger diameter than the rings 4 and 5, and revolves freely outside of,
them. Between the ring C and the stationary ring e are placed friction rolls m
of a greater diameter than the width of the grooves f and g, so that they rest
on the rings 4, 5, and 6, 7, and fill the space between the rings C and e, the
loose-ring C rolling around on these friction rolls. To prevent these rolls m
from running in contact with each other, and grinding together, another series
of rolls o, of less-diameter but of greater length, is introduced, one between each
roll m; these rolls olie in the grooves. f and g, and revolve freely therein.
Instead of the small rolls o, I sometimes employ blocks p, Fig. 3, which are
curved out on each side to match the rolls m, and are introduced between the
rolls.m to keep them separate, but are not intended to receive the bearing of the
ring C unless a weight should be applied to the ring sufficient to crush the
rolls m or to indent them into the ring. Before this, however, can take place
to any considerable degree the ring C will be supported by the blocks p (when
these are used as in Fig. 3) or by the rings 4 and 5. Any required degree of
strength may be given to the ring e, whilst the form of the shell with the
opening B in the centre allows the block to be made light in proportion to its
power and strength; or in some cases, where lightness is not so much an object,
the shell may be made whole, that is, without the opening B, and, instead of
the ring e, a solid disc may occupy the centre of the block, and serve as a
bearing for the friction rolls m.
The following are some of the advantages which I claim that this con-
struction of block possesses in an eminent degree. First, small size and lightness
in proportion to the amount of weight or strain the block is capable of
sustaining; second, a small amount of friction commensurate with the power
and strength of the block; third, non-liability of the bearings to be crushed or
deranged, either by great strain suddenly applied, or by a weight suspended
for a long time on the block.
a
In Fig. 4,. A represents a wooden block;. 'B', the strap; C¹, the wooden
sheave, in the centre of which is inserted a metal bushing D¹ of the following
construction-The box a¹, of brass or other suitable metal, is let into the
sheave, and is secured in place by screws c¹ or by rivets passing through its
rim. A cap b¹ closes the other side of the box; it rests on a shoulder 3 on
the inside of the box, and is secured by pins or screws passing through the
side of the box into the edge of the cap. E' is the pin or axle on which the
sheave revolves; it passes through and fits in the strap. B!, and, is secured
by a nut f. A sleeve g¹ is introduced into the bushing. D, through-which-the-
pin E passes, and which turns freely on this pin it is turned down at each

page_text: a¹
end, where it passes through the face of the box a' and 'through the cap b¹,
leaving a larger portion 4 in its middle, which prevents its working out endwise.
Between the sleeve 9 and the box a¹ is introduced a series of friction rolls h¹,
on which the sleeve rolls, and a series of blocks, Fig. 4, one of which is
placed between each roll h', to keep them apart and prevent them grinding one
on the other. These blocks are of the same length as the rolls, but their
depth is rather less than the diameter of the rolls, so that the sleeve shall bear
on the rolls. The circle of friction rolls is thus increased in size by the
thickness of the sleeve, which causes the rolls to operate more freely than they
would in a smaller circle; and if from any great or sudden strain the rolls
should be crushed and cease to operate, the pin E¹ will turn freely in the
sleeve g¹, and the block will be as efficient and run as easily as an ordinary
block. This construction of bushing also has another advantage, that when a
weight is suspended on the block the axle or pin E' cannot lie between any
two of the rolls h¹ and force them apart, as is liable to be the case in some
other blocks in which friction rolls are used, and in which the pivots of the
rolls are often broken in this manner. Instead of the blocks between the
rolls h', smaller intermediate rolls may be introduced, one between each roll h¹,
in which case the smaller rolls will run in grooves formed in the box a¹ and
cap 6 for the purpose. My improvements may also be applied to metallic
blocks and sheaves.
Having now set forth the nature of this Invention, and explained the manner
of carrying the same into effect, I wish it to be understood that under the
above recited Letters Patent I claim,-
First, a hoisting block having a loose metal ring C (which takes the place
.of a sheave) in combination with the central bearing e and the friction rolls m,
.operating substantially as specified.
: Second, the sleeve g¹ in combination with the box a¹ and friction rolls h¹,
substantially as described.
Witnesses,
THоs. R. ROACH,
P. E. TESCHEMACHER.
WATSON DUCHEMIN. (L.B.)