Improvements in Belt or Rope Pulleys.
Year: 1894

page_text: Date of Application, 30th June, 1894
Complete Specification Left, 5th Mar., 1995-Accepted, 20th Apr., 1895
Improvements in Belt or Rope Pulleys.
I. RAYMOND COMBRET, of 36 Rue Washington, Paris, France, Doctor of
Chemistry, do hereby declare the nature of this invention to be as follows:-
This invention has for its object to facilitate and cheapen the manufacture of
bent wood pulleys employed in the transmission of power by means of ropes or
belts; to increase the resistance of such pulleys to the pressure of the ropes or
belts that run on them, and to enable the naves of such pulleys to be more easily
changed for the purpose of making them suitable for use either as loose or as fixed
pulleys. Furthermore when such a pulley is used as a fixed pulley, it is connected
with the shaft without the use of any metallic bearings, which always involve the
danger of being capable of sliding.
In the accompanying drawings,
Figs. 1 and 2 are respectively a front elevation and a horizontal section of an
improved pulley according to my invention made in two halves.
Fig. 3 shows the inside of one of the halves; and
Figs. 4 and 5 are respectively a front elevation and an inner view of a pulley
intended for wide belting.
b
Instead of spokes I use cross-pieces (see Fig. 1) whose ends take into recesses
in the two halves (made of bent wood) of the rim a the said cross-pieces being,
when the pulley is put together, conveniently pushed sideways, into the said
recesses.
In order to transmit to the cross-pieces b, as completely as possible, and under
the most favourable circumstances, the pressure exerted on the circumference of
the pulley, and also to give to them the strength required for resisting that pressure,
angular cheeks c are provided whose inner faces are curved, and which bear on two
sides against the cross-pieces, and on their outer sides against the inner surface of
the rim, to which parts they are firmly secured by screws ab. In this manner,
two adjoining checks c that abut against each other flush with the joint of the two
halves of the pulley form a kind of arch, the strength and resistance of which
may be considerably increased by arranging direction of the fibres of the cheeks
at an angle of about 45° with the direction of the fibres of the rim and of those
of the cross-pieces.
The strength of the connection is further increased by rods d that pass through
the two cross-pieces and the cheeks c, whose projecting ends are screw-threaded so
as to allow of nuts d¹ being screwed on to them to hold the cheeks in position.
Between the cross-pieces are inserted wooden bearings that form the nave of
the pulley and are secured to the cross-pieces by rods g and nuts g', in the same
manner as the cheeks are secured; owing to which arrangement the bearings can
at any time-be easily exchanged by unscrewing the nuts g¹ and removing the rods g.
As will be readily understood, according to the diameter of the circular aperture
between the two bearings f, the pulley can be worked either as a fixed or a loose
pulley; in the first case, the nuts gl are screwed down tightly so as to force the
bearings against the driving shaft, the pulley being thus firmly jammed on to
the latter, without using any metallic brasses.
For wide belts, the rim is made either of a single wide piece of bent wood or of
the required number of narrow pieces a of bent wood (Figs. 4 and 5) glued

page_text: together, and fastened by being pressed together in a suitable frame. In order to
increase the strength, the fibres of each wooden element of the rim are at an acute
angle to the fibres of the adjoining element.
The interchangeable bearings may be replaced by an entirely metallic nave,
which, in loose pulleys, is provided with a self-acting lubricator.
If the pulley is intended for rope transmission, the circumference of the rim is
provided with the necessary grooves for the ropes, or a second wooden ring or
hoop, having these grooves formed in it, is shrunk on to the rim.
Dated this 29th day of June 1894.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
points in Delt or Rope Puneys.
I, RAYMOND COMBRET, of 36 Rue Washington, Paris, France, Doctor of
Chemistry, 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 construct belt and rope pulleys or wheels of
bent wood in a cheap and simple manner and also to render the same capable of
resisting as much as possible the strains transmitted from the belts or ropes.
The improvements also relate to an easy manner of changing the hub of the
pulley, which enables any belt pulley according to my invention to be employed
either as a fast or as a loose pulley by merely changing the hub, whilst, when it is
used as a fast pulley, it will be firmly and securely fixed to the driving shaft
without the use of metal bushes, which are liable to slip.
This invention also relates to the arrangement of circulating passages in the
pulley rim, so as to convey away quickly air that is displaced at the place where
the belt runs on to the pulley, and also to increase the friction of the belt which is
produced by the pressure of the air and is requisite for safe working.
In the drawings filed with my Provisional Specification,
Figs. 1 and 2 are respectively a side elevation and a horizontal section of a
divided or two-part belt-pulley constructed according to my invention, and
Fig. 3 shows the inside of one of the halves of the pulley.
Figs. 4 and 5 are respectively a front elevation and an internal elevation of one
half of a pulley intended for wide belting.
Fig. 6 of the drawings filed herewith illustrates a single or undivided belt pulley
of large diameter slotted on one side, and
Figs. 7 to 9 inclusive illustrate modes of connecting the bent wooden pieces that
form the pulley-rim;
Figs. 10 and I are cross sections of pulley-rims provided with circulation
passages.
As shown in Fig. 1, the pulley-rim a composed of bent wood, is divided into two
halves into which the cross-pieces b, employed in place of spokes, enter to a slight
extent, for which purpose when the pulley-rim is being put together the said cross-
pieces are slid from the side into grooves provided in the inner surface of the
pulley-rim.
For the purpose of transmitting the pressure acting on the periphery of the
belt-pulley to the cross-pieces in the most favourable manner, and at the same
time of rendering the cross-pieces capable of effectually withstanding the said
pressure, there are inserted between the cross-pieces b, angle-shaped cheeks e
internally of arc-shape, each of which bears at one side against one of the cross-

page_text: pieces 6 and at the other side against the inner surface of the pulley-rim, and is
connected to these parts by means of screws a¹ b¹.
Each two cheeks c situated adjacently to each other at the joint or place of
division of the pulley-rim halves, constitute in this manner a kind of arch the
strength and capability of resistance of which is considerably increased by the
fact that the fibres of which these cheeks are composed are arranged at angles of
about 45° to the direction of the fibres of which the cross-pieces band rim a are
composed.
The strength of the connection is further increased by means of tie-rods d each
of which passes through the two cross-pieces and a pair of cheeks c, and is screw-
threaded at both of its ends, which project from the cross-pieces, so that by
tightening up nuts screwed thereon, the cheeks c are firmly clamped together.
The wooden bearing-blocks or steps which form the hub of the pulley, are
inserted between the cross-pieces b, and are fastened firmly to them by means of
tie-rods y and screw-nuts in the same manner as the cheeks " the arrangement
being such that the said blocks or steps can at any time be readily removed and
replaced by unscrewing the nuts g', and withdrawing the rods g.
According as the diameter of the bore of the hub formed by the blocks fis
made smaller or larger, the pulley can be employed as a fast or as a loose pulley ;
in the former case by tightening up the nuts g', the blocks can be pressed so
tightly against the shaft, as to fix the pulley firmly thereon, thereby enabling
metal bearing steps or bushes to be dispensed with.
For wide belts the pulley-rim may be made of a single wide piece of wood,
divided into two halves or of a suitable number of bent pieces of wood a (Figs. 4
and 5) glued and fixed firmly to one another by pressing them together in a
clamping device, the directions of the fibres of each two adjacent portions of the
rim being arranged at an acute angle to each other with the object of increasing
the strength of the rim. Instead of the removable hub-portions f, there may be
employed, if desired, a hub consisting wholly of metal, which, in the case of loose
pulleys, can be provided with an automatic lubricating device.
In belt-pulleys of large diameter, say 80 centimetres and upwards the pulley-
rim is preferably divided by a cut or slit on one side only, so that, the flexibility
of the rim being sufficient for the purpose, the surfaces of the cut or slit cau be
moved apart from each other to such an extent as to allow of the passage of the
shaft through the slot when it is desired to remove or replace the belt-pulley. In
this case the rim a is composed of a number of pieces of wood bent together in
the form of complete rings which are bevelled at the joints s², s², s³, s (Figs. 7
to 9), the joint extending either at an angle from the inside towards the outside
(Figs. 7 and 8), or from one side or edge to the other (Fig. 9). In connecting the
several rings together the joints are arranged to break joint (Fig. 7), and the
whole rim when glued together is divided on one side by a cuts (Figs. 6 and 9).
The cross-pieces and the cheeks c are inserted in the manner hereinbefore
described except that the cheeks situated on the side opposite to the cut s (Fig. 6)
are not screwed to the cross-pieces b, the object of this being that when the
tie- rods d have been removed and the rim is opened out at the said cut, the cross-
pieces shall be capable of sliding on the aforesaid pair of cheeks and of thus
moving freely, so as to allow of the opening out of the rim. After the shaft bas
been inserted through the opened out cut, and has been enclosed by the halves fof
the hub, the halves and the shaft are brought into proper position between the
cross-pieces b; whereupon the tie-rods d and y are inserted, and a firm connection
of the parts is effected by tightly screwing up the nuts and g'.
For the purpose of stiffening the cross-pieces laterally, stretchers
shape and in suitable number may be employed, thus serving as spokes.
In order that in belt-pulleys of this kind, the air displaced at the place where
the belt runs on to the pulley-rim may be allowed to escape quickly for the purpose
of increasing the pressure, due to the atmosphere, which the belt exerts on the
pulley-rim and of thereby producing a greater amount of friction, which is so
of suitable

page_text: desirable for safe working, the bent wood rim a is formed with holes or circulating
passages (Fig. 10) or as shown in Fig. 11 with peripheral grooves which are
in communication at certain places with the said passages and are surrounded by
a perforated wooden plate which covers these grooves, the said plate being
composed of a number of superposed sheets of veneer such as are used for chair
and other seats.
Or the grooves alone may be provided in order to form communications.
between the holes in the plate / that are covered or closed by the belt and those
that are uncovered, so that the air displaced by the belt on running on the rim, is
allowed to pass away freely.
When the pulleys herein described are intended for rope-driving, the periphery
of the pulley-rim is formed with annular grooves or channels which serve to
receive the ropes, or a second wooden ring provided with such grooves is fixed
tight on the pulley-rim. For tootbed wheels (spur or bevel wheels) or friction-
wheels, there is fixed upon the rim a a toothed or friction rim made of wood
or iron.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed declare that what I
claim is :-
1. A belt-pulley or wheel consisting of a two-part divided rim a of bent wood
having cross-pieces which are fitted into each half of the rim and between which
are arranged angle-shaped cheeks or knees c, which bear close up against the inner
surface of the rim, and bearing blocks, which form the hub, the said cheeks or
knees and the said bearing blocks being connected to the cross-pieces b by means
of tie-rods or bolts d and y respectively, substantially as set forth.
2. A belt-pulley of the kind specified in the preceding claim, in which the rim a,
consisting of solid bent wood, is divided at one place by a cuts, with the object,
by forcing apart the sides of the cut, of enabling the belt pulley to be mounted on
or removed from the shaft.
3. A pulley of the kind specified in Claim 1, in which the rim consists of a
number of bent pieces of wood fastened together laterally by being glued and
firmly pressed together, the pieces of wood being so arranged that the directions
of the fibres of laterally adjacent pieces make acute angles with each other
substantially as herein described.
Dated this 5th day of March 1895.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.