Year: 1886

page_text: I, PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents do hereby declare the nature
of this Invention (a communication from abroad by Wallace Harlow Dodge of
Wishawaka, State of Indiana United States of America, Manufacturer) and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
I am aware that pulleys have heretofore been made of wood, and therefore I do
not propose to broadly claim pulleys made of that material, but I believe to be
new the method and manner of fashioning and uniting the several parts, in the
particulars hereinafter described and pointed out in the claims.
That a complete understanding of this improvement may be had I will par-
ticularly describe the manufacture of a pulley from the beginning.
In the first place I obtain suitable wood sawed into boards about one inch in
thickness. In America I use cheap woods such as poplar, baswood and the like for
ordinary purposes and blackwalnut, mahogany and other finer woods for particular
or show purposes. I first mark out on said boards, circular segments of proper
curvature for a pulley of the desired diameter. Each segment constitutes one
fourth or some other division of the circle so that a certain number of them will
form a complete ring. These segments are shown in Fig. 1 and indicated by the
letter A, the segments A are then cut out with a saw, cut to exact length and the
ends made truly radial.
The segments A are then joined at their ends as shown in Figs. 2 and 3 and
secured together to constitute a complete ring which in the subsequent operations
may be handled as an entirety. This preliminary joining of the segments at their
ends to constitute rings is of importance because, it facilitates the work and more
especially because it ensures sound joints at the segment ends and enables me to
dispense entirely with the use of nails, which before my invention have been
universally used to fasten together the parts of a wooden pulley rim.
When the pulley is of small diameter the rings shown in Figs. 2 and 3 may
simply be united at their ends by glue, being pressed together by the hands and
laid away until the glue has hardened. When of somewhat larger diameter, or, if

page_text: more than four segments are employed it is necessary to use a clamp to hold the
segments in place, while the glue is hardening, and for this purpose I have
employed a simple strap of iron with a tightening screw to draw the ends together
as shown in Fig. 2 and I have also employed a variety of jawed clamps with
screws and with coincident movement like the jaws of a lathe chuck, but the clamp
is not new.
When the pulley is to be of large size I employ fastenings of some
sort to mechanically join the ends of the segments as shown in Fig. 3, and such
fastenings may consist of metallic staples similar to those shown at a, or of wooden
dowels or keys, the preferable form being the double dovetailed key shown at b.
These hold the segments together while being handled after their ends have been
glued.
After the segmental rings have been formed as above described they are packed
together with glue between, in number corresponding to the width of the face of
the desired pulley, as shown in Fig. 4.
The segmental rings so put together are relatively arranged to break joints and
their united thickness is equal only to the width of the spokes or arms, leaving
the rim portions to be afterwards added as will be hereinafter more particularly
explained.
When the segmental rings have been glued and packed together as just explained,
they are placed under strong pressure until the glue has thoroughly hardened, and
by using heated segments alternately with the segments covered with glue the
material for several pulleys can be prepared and squeezed in a press at the same
time. These rim rings are then chucked and their interior surfaces are turned
truly cylindrical.
The arms or spokes B for the pulleys are made of suitable hard wood. In width
and thickness they are proportioned to the size of the pulley and the power they
are designed to transmit. I find it desirable to employ two arms extending from
side to side as shown, and having the hub D between them because it is desirable to
make every pulley separable, and because in that way the material can be disposed
to the best advantage to secure strength and lightness. It will be evident however
that the rim of the pulley may not be divided if, for any reason a continuous rim
is preferred, see Figs. 5, 6, 7 and 8.
The arms and hub might be cut from a single piece but it is evident that would
incur waste of material, and I therefore cut planks to suitable width thickness and
length. I then cut transversely a shallow notch d suitable to receive and seat the
hub block, and at each end I cut a dovetail tenon e, which is to be inserted into the
substance of the rim. A dovetail tenon is preferred because that will restrain the
rim from expansion but to avoid the nice fitting which is necessary to dovetailed
joints, I cut one edge of my dovetail thinner than the other as shown and when
inserted in its mortice I drive in a wedge f, which ensures a solid and permanent
joint, see Figs. 9 and 11.
After the arms B, have been inserted and secured in the rim as shown and
described said rim is cut between said arms on irregular lines g, and the clamping
bolts are inserted, the irregular cut g then constitutes interlocking surfaces to
retain the ends of the rim properly in place.
The hub blocks d, do not meet by a little space, say one fourth of an inch, and
after the rim has been severed and the bolts h inserted, in strips, are placed
between said hub blocks near their ends before the bolts are tightened up.
The pulley is then returned to the lathe and chucked in the same marks as when
the interior of the rim was bored, so that it is truly centered on the same axis as
before. The hub is then bored to some standard size, see Figs. 8 and 12.
Segmental rings are then added and glued fast to each edge of the pulley to
build the same out to the desired width of face. These added rings cover and
conceal the dovetailed tenons e, which are thereby completely embedded in the
substance of the rim, and incapable of withdrawal without destruction of the parts.
The segment rings added as just described are then severed with a straight saw
on a line joining the two ends of the irregular cut g, as shown in Figs. 10 and 14

page_text: and thereby the severed surfaces are rendered interlocking laterally as well as
radially.
The pulley having now been centerbored is placed on a mandril and turned true
on its face and also finished on its edges.
It is then carefully balanced by inserting pieces of metal at proper points in its
rim, and after that it is finished with paint and varnished to suit the taste or fancy.
When the pulley is of very large diameter, or required to withstand heavy.
pressure, additional arms I are inserted extending from the hub D radially to the
rim, and the number of these arms may be greater or less as necessary for the
purpose in view. I find it desirable to seat them in iron sockets on the hub blocks
as shown, see Fig. 15.
When the pulley is designed to transmit an unusual amount of power so that
the draft strain is heavy, it is desirable to relieve that small portion of wood
between the thrusting tenon e and cut d, from the thrusting strain, and I therefore
insert an anchor J in the material of the rim, and connect the end of the arm B
with said anchor by a stay bolt K, as shown in Figs. 16 and 17.
The dealer in ready made pulleys finds it necessary to be prepared to furnish a
pulley of any standard size fitted to any shaft of standard diameter. To do so
requires the keeping in stock of a set of pulleys of each standard size differently
bored to fit the range of shaft diameters.
To avoid this hard necessity I make all pulleys within certain arbitrary limits
of standard proportions throughout and with removable bush or hub blocks so that
a bush or hub block properly bored to fit any shaft, may be inserted in any pulley,
and thus at a moments notice any pulley in stock may be fitted to any shaft.
To keep a full assortment of bushings or hub blocks interchangeable with all the
pulleys in stock, is a comparatively simple and inexpensive matter and is entirely
practicable, as shown in Fig. 13.
The hub being split and fitted accurately to the shaft is firmly clamped thereon,
by tightening the bolts h.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent I declare that what I claim is
1. An improvement in the process of making wooden pulleys from segments A, A,
which consists essentially in joining said segments at their ends to constitute
individual rings as set forth, whereby, in the final assembling of parts to constitute
the pulley, said rings may be handled as entireties, and glued together as set forth,
without the use of nails.
2. The circular segments A provided in each end with a dovetailed notch
combined with the double dovetailed keys adapted to fit said notches, whereby
said segments are joined in rings adapted to be assembled and glued together to
constitute a pulley as set forth.
3. A wooden pulley consisting essentially of segments A, united at their ends as
set forth, several of the resulting rings being glued together substantially as set
forth.
4. The mode or procedure in building a wooden split pulley, herein described
which consists in first building the central part of said rim, second in dividing the
same transversely on an irregular line to make an interlocking joint, third in
adding a section to each edge of said central part and dividing the same on a
straight line, whereby the adjoining ends of the rim are provided with interlocking
portions as set forth.
5. A wooden split pulley provided with interlocking projections and recesses in
the adjoining ends of the rim formed by dividing the same on a curved line
substantially as set forth.
6. A pulley provided with the arm or spoke B having at its ends the wedging
dovetailed tenons e fitting in dovetailed mortices in the pulley rim and the
fastening wedges substantially as set forth.
;

page_text: 7. In a wooden split pulley the central part of the pulley rim cut transversely on
an irregular line; the arms B inserted at their ends, into the rim with a dovetailed
mortice, the exterior edge portions of the rim glued on, covering the arm tenons
and the irregular cut referred to, and said exterior edge section divided on a
straight line, whereby the spoke or arm tenons are firmly incorporated with the
material of the rim, and the adjoining arms of said rim are firmly interlocked with
each other.
8. A split pulley having section A, and the arm B morticed into the same near
its end, and provided with a stay bolt K extending from said arm back to the
pulley rim at a distance from its end substantially as set forth.
9. A split pulley having rim A and the arm B morticed into the same near its
point of division and provided with the stay bolt K and the anchoring pin J,
inserted in the rim as set forth.
10. The rim and arms of a separable pulley combined with removable and inter-
changeable center blocks, the seating of said center blocks being in standard sizes
and the center bore in various sizes to suit shafts of different diameters, whereby
the same pulley may, by interchange of center blocks, be adapted to fit any desired
shaft.