IMPROVEMENTS IN THE MEANS OR APPARATUS FOR DRIVING SEWING MACHINES, LATHES, OR OTHER MACHINERY
Year: 1876

page_text: LETTERS PATENT to Martyn John Roberts, of the City of Bath, Esquire, for
the Invention of "IMPROVEMENTS IN THE MEANS OR APPARATUS FOR DRIVING
SEWING MACHINES, LATHES, OR OTHER MACHINERY."
Sealed the 21st December 1876, and dated the 28th June 1876.
PROVISIONAL SPECIFICATION left by the said Martyn John Roberts at the
Office of the Commissioners of Patents on the 28th June 1876.
MARTYN JOHN ROBERTS, of the City of Bath, Esquire. "IMPROVEMENTS IN THE
MEANS OR APPARATUS FOR DRIVING SEWING MACHINES, LATHES, OR OTHER
MACHINERY."
In the driving of machinery by bands, belts, cords, or the like, passed round
pulleys, wheels, drums, or other similar contrivances, it is essential that the band
should be sufficiently tight to "bite" upon both, the driving pulley (or similar
contrivance) and the driven pulley in order that it may produce the requisite
adhesion between band and pulley to drive them. This tightness of the band
has the effect of pulling the pulleys with great force against their bearings, and
much friction is thereby caused. Further, as bands and belts lengthen and shorten
by changes of the atmosphere, and also become longer through wear, the band must
either be made very tight at first, or it must require continual adjustment. Again,
the off-going or trailing portion of the band is always slacker than the on-going
portion, and this prevents a perfect bite.
Now my Invention consists in moans whereby the band is always kept auto-
matically at the requisite degree of tension to give sufficient bite or adhesion,
notwithstanding atmospheric changes and wear, while the off-going portion is as
tight as the on-going portion of the band, and the friction is much reduced.
.
I mount the lower of the two pulleys which are in gear by belt or band in a
standard or bearing, which is formed with a vertical or slanting slot to receive the
axle or spindle of the pulley, and I make this lower pulley of lead or otherwise
sufficiently heavy to keep the band always at the requisite degree of tension. The
weighted pulley is as it were slung in the band, and has but little other vertical
support, while the sides of the slot keep it from moving laterally. Any alteration
in the length of the band is immediately compensated for by a corresponding
downward or upward movement of the weighted pulley in the slot, while the
friction on the axle of this pulley is reduced to a minimum.
Price 6d1

page_text: In order to communicate motion to the weighted drum or pulley (if the driving
pulley) or from it (if the driven pulley) it is connected with a shaft (say having
fixed bearings, such, for example, as the shaft of a sewing machine or lathe) by
means of a universal joint. The weighted pulley may be put out of gear by
simply lifting it so as to render the band slack.
Instead of making the pulley itself of sufficient weight for the purpose of my
Invention, it may be mounted in a sufficiently heavy frame or bearing which is
free to rise and fall in vertical guides, or the upper pulley, or a frame in which it
is mounted, may have a weight attached to it by means of a cord which passes over
a point above.
In cases where the driving band crosses itself between the weighted and other
pulley, I prevent it rubbing at the crossed part by inclining the axles of one of the
pulleys to the other.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Martyn John Roberts in the Great Seal Patent Office on the 27th
December 1876.
"IMPROVEMENTS IN THE
MARTYN JOHN ROBERTS, of the City of Bath, Esquire.
MEANS OR APPARATUS FOR DRIVING SEWING MACHINES, LATHES, OR OTHER
MACHINERY."
"
In the driving of machinery by bands, belts, cords, or the like, passed round
pulleys, wheels, drums, or other similar contrivances, it is essential that the band
should be sufficiently tight to "bite upon both the driving pulley (or similar
contrivance) and the driven pulley in order that it may produce the requisite
adhesion between band and pulley to drive them. This tightness of the band
has the effect of pulling the pulleys with great force against their bearings, and
much friction is thereby caused. Further, as bands and belts lengthen and shorten
by changes of the atmosphere, and also become longer through wear, the band
must either be made very tight at first, or it must require continual adjustment.
Again the off-going or trailing portion of the band is always slacker than the
on-going portion, and this prevents a perfect bite.
Now my Invention consists in means whereby the band is always kept auto-
matically at the requisite degree of tension to give sufficient bite or adhesion
notwithstanding atmospheric changes and wear, while the off-going portion is as
tight as the on-going portion of the band, and the friction is much reduced.
I mount the lower of the two pulleys which are in gear by belt or band in a
standard or bearing, which is formed with a vertical or slanting slot to receive the
axle or spindle of the pulley, and I make this lower pulley of lead or otherwise
sufficiently heavy to keep the band always at the requisite degree of tension.
The weighted pulley is as it were slung in the band and has but little other
vertical support, while the sides of the slot keep it from moving laterally. Any
alteration in the length of the band is immediately compensated for by a corre-
sponding downward or upward movement of the weighted pulley in the slot,
while the friction on the axle of this pulley is reduced to a minimum.
In order to communicate motion to the weighted drum or pulley (if the driving
pulley) or from it (if the driven pulley) it is connected with a shaft (say having
fixed bearings, such, for example, as the shaft of a sewing machine or lathe) by
means of a universal joint. The weighted pulley may be put out of gear by simply
lifting it so as to render the band slack.
Instead of making the pulley itself of sufficient weight for the purpose of my
Invention, it may be mounted in a sufficiently heavy frame or bearing which is
free to rise and fall in vertical guides, or the upper pulley, or a frame in which it
is mounted, may have a weight attached to it by means of a cord which passes
over a point above.

page_text: In cases where the driving band crosses itself between the weighted and other
pulley, I prevent it rubbing at the crossed part by inclining or skewing the axles
of one of the pulleys to the other.
In Figures 1 and 2 of the annexed Drawings I shew the manner in which my
Invention may be applied to a treadle sewing machine, and in Figures 3 and 4 to
a lathe. In each of these Figures a is the driving or treadle shaft turning in fixed
bearings b, b; c is a Hook's or universal joint connecting the shaft a with the
shaft or spindle d of the driving pulley e. The opposite end of the spindle has its
bearing either in a slot f in the standard g (Figure 1) or in a block h (Figure 3)
which is free to slide in the slot f; in the standard i is the band or belt for trans-
mitting motion to the pulley k on the upper shaft l. The pulley e is of lead, or is
otherwise made sufficiently heavy to keep the band i always at the requisite
degree of tension, the slot f giving the said pulley perfect freedom of movement to
allow for compensation in the length of the band.
And having now described the nature of my said Invention, and in what manner
the same is to be performed, I declare that I claim as my "Improvements in the
Means or Apparatus for Driving Sewing Machines, Lathes, or other Machinery'
First. Mounting pulleys, wheels, drums, or other similar contrivances, from or to
which motion is communicated by bands, belts, or the like, in slotted bearings, or
in blocks free to move up and down in guides, and making such pulleys or other
similar contrivances, or the said blocks, of sufficient weight to allow of their keeping
the said bands or belts at the requisite degree of tension while always compensating
for any alteration in the length of the bands or belts, substantially as herein-before
described.
Secondly. In combination with pulleys, wheels, drums, or other similar con-
trivances, mounted and weighted as aforesaid, I claim the employment of a universal
joint for connecting the pulley, spindle, or shaft with the shaft from or to which
motion is to be communicated, substantially as herein-before described.
Thirdly. In combination with pulleys, wheels, drums, or other similar contrivances,
mounted and weighted as aforesaid, I claim the placing of the axles of the driving
and driven pulleys, or other contrivances, at an inclination, or skewed to each other,
as and for the purpose herein-before described.
In witness whereof, I, the said Martyn John Roberts, have hereunto set my
hand and seal, this Twenty-second day of December, One thousand eight
hundred and seventy-six.
MARTYN J. ROBERTS. (L.S.)