Improvements in Belt Driving Mechanism for Machinery.
Year: 1894

page_text: Date of Application, 23rd June, 1894-Accepted, 28.h July, 1894
COMPLETE SPECIFICATION.
Improvements in Belt Driving Mechanism for Machinery.
I, FRANCIS HIRAM CRAFTS of Seventh and Hudson Streets, in the City of
Buffalo, in the County of Erie, State of New York, United States of America,
Manufacturer, do hereby declare the nature of my invention for IMPROVEMENTS IN
BELT DRIVING MECHANISM FOR MACHINERY and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to improvements in belt driving mechanism for machinery.
The object being to secure the instantaneous change in the speed of the machine
without sidewise shifting of the power-transmitting belt.
In the accompanying drawings my improvements are shown as applied to an
engine Inthe though they are equally applicable to other machines where cone
pulleys or stepped cones and power-transmitting belts are employed.
In the drawings,-
Figure 1 represents a rear elevation of part of a lathe frame having one form of
my improvement applied thereto.
Figure 2 represents a section thereof on the line a, a, of Figure 1.
Figure 3 represents a front elevation, and
Figure 4 a transverse section of part of a lathe frame illustrating a modified
arrangement.
In each of the forms illustrated the principle is the same which, briefly stated,
consists in the employment of a pair of parallel shafts, one connected with the
source of power and the other connected with the mechanism to be actuated, a
pair of stepped or cone pulleys located on said shafts, belts connecting each step of
the respective cone pulleys, reciprocating belt-tightener disks adapted to engage
the respective belts and rods or levers for actuating said belt-tightener disks and
regulating the tension of the belts.
Referring to Figures 1 and 2:
I represents the frame of the machine, 2 the counter-shaft located in bearings at
any desired position near the bottom of the frame either below or above the
floor, provision being made for dropping the counter-shaft, should the belts become
so slack as to necessitate reducing them, by throwing the counter-shaft further
away from the spindle. By placing the counter-shaft below the floor belts of
greater length may be employed. 3 represents band-pulleys or other devices
connecting with the source of power. 4 represents the spindle shaft. On these
shafts 2 and 4 are located oppositely-positioned cones or stepped pulleys 5, 6,
connected by belts or bands 7 equal in number to the respective steps. 8 represents
ruds or levers corresponding in number with the number of steps in the pulleys and
having removable pivotal bearing 8 at their lower ends 9 in a suitable frame or
socket 10. Bolted or otherwise secured or formed integrally with said rods or
levers 8 at a suitable portion of their length are a series of armis 11 on the inner
ends of which are supported disks 12 by means of which the belts 7 may bc
tightened and their tension on the stepped on cone pulleys regulated at will so as
to bring either one into operative contact with said pulleys and thereby regulate
the speed of the machine. Extending forwardly from and at a right angle to the
upper end of each rod or lever S is an arm 13, which may be either formed integrally
therewith and have notches or teeth 14 on their underside, or said members 13,
niny, as shown, be in the form of toothed racks and be attached to the levers 8
by couplings or sleeves 15: at the front ends of these arms or racks are
hand-grasps 16 by means of which the racks or toothed arins 13 and the

page_text: thereto-connected levers 8 may be reciprocated and rocked on the pivots 8* so as
to reciprocate the belt-tightener disks against or from the belts. These racks or
toothed arms have guide-bearing in eyes 17 which are notched or toothed to engage
the teeth on the racks and hold said racke in adjusted position.
The several parts above described being assembled, with all the levers in their
reartnost positions all of the belts will be idle. When it is desired to rotate the
spindle at a comparatively low rate of revolution the operator grasps the hand-
grasp of the lever adjacent to that step of the pulley having the largest circum-
ference, and draws the rack and lever connected with said hand-grasp forward
whereupon the disk connected with said lever brought into contact with the belt
to tighten it against the respective steps. When it is desired to increase the
rotation of the spindle shaft the rack at the time in engagement is released and it
and the lever pushed back, which act releases the disk on said lever from tensional
engagement with the belt in operation, and another rack and lever correspondingly
brought forward to bring the belt-tightener disk into frictional engagement with
the desired belt. The action of the parts is very simple and results, as will be
readily understood, in securing an easy, ready and instantaneous change in the
speed of rotation of the spindle or other device to be actuated without injury
to or wear of the belts, and without stopping the machine or endangering the
operative.
Onlinarily, where a plurality of pulleys, or stepped pulleys, are mounted on
power-operating shafts, a single belt has been employed which, as it is desired to
change the speed of the machine, has been shifted from one pulley or from one
step of the pulley to another. Manifest disadvantages, it is well known, result
from the necessity of so shifting the belt, especially where considerable change
in the speed of the machine is desired, the time employed in shifting the belt is a
material loss, and the belt is injured by frequent sidewise shifting. By the employ-
ment of a distinct belt for each step of the pulleys employed in connection with a
belt-tightener, or tighteners, by which the individual belt, alone, may be placed in
operative connection with the respective pulleys and the remaining belts allowed
to run idle according to the speed at which it is desired to run the machine
the former disadvantages are avoided and the distinct advantages above set
forth secured.
The width of the disks 12 preferably equals that of the belts so as to bear
evenly across their faces, though the respective widths may vary.
Referring to the modification shown in Figures 3 and 4 the rods 8 for
reciprocating the belt tightener-disks 12 to bring said disks into or out of
tensional engagement with the belts have right-angled inner ends which extend
through said disks and have slidable bearing within grooved boxes or brackets 19
on the frame, said grooves being of about equal size with the inner ends 18 of the
disk-operating rods to ensure steady bearing for snid ends 18, which constitute the
disk journals, admit of the easy reciprocal movements of said rods and disks and
prevent their oscillation. The rods & in this arrangement extend out beyond
the front of the frame of the machine, passing through an opening 21 therein,
their outer ends having hand-grasps 16 and being notched or toothed on their
under edge, as at 22, which teeth 22 engage with either the upper edge of a
plate 23 at the front of the frame or with the lower edge of the opening 21.
The operation of the several parts is the same in each form shown.
When it
is desired to adjust the speed of the machine the front end of the lever or rod 8
connected with the belt-tightener disk it is desired to operate is raised so as to release
the rack or teeth thereon from locking engagement, the lever or rod is then
either pushed rearwardly or drawn forwardly according as it is desired to either
release the disk 12 connected therewith from or bring it into frictional contact
with the belt adjacent thereto; such desired adjustment having been accomplished
the notched front end of the rod or lever is then placed in engagement with the
teeth, plate, or edge of the opening 21 as the case my be, whereupon the rod or
lever and belt-tightener disk are securely held in their adjusted positions.

page_text: It will be observed that by means of the racks and teeth on the disk-operating
levers the disks 12 can be held against the belts at any desired degree of pressure
and, consequently, the degree of tension on the respective belts readily regulated
and their tension maintained at all times and under all circumstances. This is
especially advantageous in admitting of the instantaneous adaptation of the machine
to either heavy or light or medium work as by a slight adjustment, either
rearwardly or forwardly, of the disk-operating lever, or levers, the machine can be
made to run either heavy or light, according to the work under treatment, by the
degree of pressure exerted upon the belt in use by the adjacent disk.
By locating the counter-shaft below the spindle shaft in contradistinction to the
location of the counter-shaft above the spindle shaft, and the employment of a
single sidewise-shiftable belt, I avoid the disadvantages of the belt pulling upon the
spindle and the consequent tendency of the lifting up of the tool, which results in
an undue friction on the cap of the journal and the cutting of the box, which
produces more or less lost motion.
While I have described my improvements in connection with the employment of
stepped pulleys or cones, it is manifest that they are equally adapted for use in
such cases as where a plurality of individual pulleys, instead of cone pulleys, are
employed.
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. Driving mechanism for instantaneously changing or regulating the speed of
machinery, consisting of a power shaft, an operative shaft, cone pulleys located on
said shafts, belts located on and connecting the respective steps of said pulleys
and reciprocal belt-tightening devices adapted to independently engage the respective
belts, substantially as and for the purposes set forth.
2. As an improvement in mechanism for changing the speed of machinery, the
herein described means consisting of a shaft connected with the source of power, a
shaft connected with the tool or mechanism to be operated, stepped pulleys reversely
positioned upon said shafts, belts or bands connecting, individually, the respective
steps of said pulleys, disks equal in number with and having reciprocal bearing
adjacent to each belt, levers connected with said disks and adapted to reciprocate
the same into tightening contact with or away from said belts, and means for
locking said levers in their several positions, substantially as and for the purpose
set forth.
3. The means herein described for transmitting power to and driving belt
machinery and changing and regulating the speed thereof, consisting of a power-
connected shaft and a shaft connected with the mechanism to be operated, a
plurality of either plain or stepped pulleys located on said shafts, belts connecting
the respective pulleys or steps thereof, independent belt-tighteners adapted to
independently engage each individual belt, and levers adapted to reciprocate each
belt-tightener, individually, into or out of frictional engagement with the respective
belts, substantially as and for the purposes set forth.
4. As an improvement in drive-mechanism for machinery, a pair of parallel
shafts, stepped cones located thereon, a plurality of drive belts located on the
respective steps of said cones and connecting the same, a plurality of disks, and a
series of pivoted levers connected with said disks and adapted to reciprocate the
same into and out of contact with said belts, substantially as and for the purpose
set forth.
Dated this 22nd day of June 1894.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.