IMPROVEMENTS IN SCREW AND LEVER PRESSES
Year: 1879

page_text: LETTERS PATENT to Thomas Wrightson, of Stockton on Tees, in the County
of Durham, Engineer, and John Haskins Ladd, of Queen Victoria Street, in
the City of London, Engineer, for the Invention of "IMPROVEMENTS IN
SCREW AND LEVER PRESSES."
Sealed the 23rd January 1880, and dated the 28th July 1879.
PROVISIONAL SPECIFICATION left by the said Thomas Wrightson and
John Haskins Ladd at the Office of the Commissioners of Patents on the
28th July 1879.
THOMAS WRIGHTSON, of Stockton on Tees, in the County of Durham, Engineer,
and JOHN HASKINS LADD, of Queen Victoria Street, in the City of London,
Engineer. "IMPROVEMENTS IN SCREW AND LEVER PRESSES."
Our Invention relates to improvements in the screw and lever presses described
in the Specification of Letters Patent dated 12th September, A.D. 1873, No. 3003,
and comprises a novel arrangement of frictional or friction wheel gearing designed
to afford the means for imparting or communicating motion in a very advantageous
manner to the screw shaft of these and similar presses.
The said presses as described and shewn in the Specification of the said former
Letters Patent have a double threaded screw, that is to say, a screw which has on
it threads cut in opposite directions on its two ends; this screw is thereby connected
to toggle-levers or links, and through these levers it operates a follower under which
are placed the articles or substances to be pressed. The presses, as described in the
said former Specification, have provision for operating them by means of a hand
lever, but by subsequent improvements these presses have been provided with a
driving shaft connected by toothed gearing with the said double screw and driven
by a belt or otherwise from a steam engine or other motor.
Our present improvements are designed to facilitate the operation or working of
these presses by combining with the screw-shaft and levers and other parts of the
same the aforesaid convenient and simple arrangement of frictional wheel gearing
which we will now proceed to describe.
For this purpose we provide the press with a main or driving shaft upon which
at or near one end thereof is fixed a pulley for the reception of a belt or band,
whereby the same is connected with the steam-engine or other motor. This shaft
Dmine 71

page_text: has fixed on its other end a wheel or roller which we term a friction-pinion. The
said pinion is arranged in combination with a large wheel which we term the
friction-wheel, and which is fixed on a counter shaft arranged parallel with the
said driving shaft. The said friction-wheel has an inner and outer frictional surface
and the said pinion projects between these two surfaces and is so arranged that it
may be adjusted to gear or work in contact with either of these surfaces, or to be
out of gear with the same. For this purpose the bearing which supports the end
of the main shaft adjacent to the said pinion is made adjustable so that the said
shaft and pinion can be moved toward or from the centre or axis of the aforesaid
friction-wheel, or the end of the shaft on which the friction-wheel is fixed may be
made to move so that its concave or convex surface is in contact with the friction-
pinion.
In ordinary cases it will not be necessary that the bearing for the other end of
the shaft should be made movable, as the extent of adjustment is so slight that the
shaft, unless very short in proportion to its diameter, will have sufficient elasticity
or freedom in the said bearing to permit the required adjustment without moving
the same.
This adjustment may be effected by any convenient mechanism, such as a lever
and a screw rod or spindle extending down from the said lever, and provided with
a. wheel or bandle at its lower end. In presses of the kind or class above referred
to the double screw shaft has to move vertically with the toggles, therefore this
shaft is connected to the shaft which carries the friction-wheel by gearing which
permits the free movement of the said screw shaft while keeping the same in gear
with the said friction-wheel shaft, as described in the Specification of Letters
Patent dated 5th February, A.D. 1877, No. 477, or otherwise.
In the operation of the press when the follower is to be forced downward the
said friction-pinion is caused to gear or work in contact with the outer or large
frictional surface or rim of the friction-wheel, and will then impart to the follower a
slow motion with a very powerful pressure, but when it is desired to raise the said
follower, the friction-pinion is caused to work in contact with the inner or small
frictional surface of the said wheel; the follower will then have a comparatively
quick motion.
This capability of varying the speed of the machine affords the means for greatly
economizing time in the working of the same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Wrightson and John Haskins Ladd in the Great Seal Patent
Office on the 28th January 1880.
THOMAS WRIGHTSON, of Stockton on Tees, in the County of Durham, Engineer,
and JOHN HASKINS LADD, of Queen Victoria Street, in the City of London,
Engineer. " IMPROVEMENTS IN SCREW AND LEVER PRESSES."
Our Invention relates to improvements in the screw and lever presses described
in the Specification of Letters Patent dated 12th September, A.D. 1873, No. 3003,
and comprises a novel arrangement of frictional or friction wheel gearing designed
to afford the means for imparting or communicating motion in a very advantageous
manner to the screw shaft of these and similar presses.
These presses as described and shewn in the Specification of the said former
Letters Patent have a double-threaded screw, 'that is to say, a screw or shaft which
has on it threads cut in opposite directions from near its centre to its two ends;
this screw is thereby connected to toggle levers or links and through these levers
operates a follower under which are placed the articles or substances to be pressed.
The presses as described in the said former Specification have provision for operating
them by means of a hand-lever, but by subsequent improvements these presses have
been provided with a driving shaft connected by toothed gearing with the said
double screw, and driven by a belt or otherwise from a steam-engine or other
motor.
Our present improvements are designed to facilitate the operation or working of
these presses by combining with the screw-shaft and levers and other parts of the
same a convenient and simple arrangement of frictional wheel gearing which we
will now unnoood to dronniba

page_text: bearing which supports the end of the main shaft f adjacent to the said pinion is
made adjustable, so that the said shaft and pinion g can be moved toward or from
the centre or axis of the aforesaid friction-wheel h, or the end of the shaft h* on
which the friction-wheel is fixed may be made to move to bring its concave surface
h² or convex surface h¹ in contact with the friction pinion g.
In ordinary cases it will not be necessary that the bearing for the other end of
the shaft should be made movable as the extent of the adjustment of the pinion
is so slight that the said shaft, unless very short in proportion to its diameter, will
be sufficiently elastic or will have sufficient freedom in the said bearing to permit
the required adjustment without moving the same.
This adjustment of the bearing may be effected by any convenient mechanism,
such as a lever connected with a screw-rod or spindle extending down from the said
lever and provided with a wheel or handle at its lower end.
Instead of employing an adjustable bearing for the shaft f adjacent to the friction-
pulley g, we in some cases mount the shaft finside a hollow shaft lc which is provided
with excentrics fitted in the bearings * and which when turned by the arm or
lever operated by hand or by means of a rod or screw, or in any other suitable
manner, will adjust the pinion g into contact with either of the surfaces h¹, h², or
out of contact with either of them as desired.
In presses of the kind or class above referred to the double screw-shaft b has to
move vertically with the toggles d, therefore this shaft is connected to the shaft h*
which carries the friction-wheel h by gearing which permits the free movement of
the said screw-shaft while keeping the same in gear with the said friction-wheel
shaft h*.
In order to ensure this result in the press shewn in Figures 1 and 2, the shaft h*
is provided with a bevelled toothed pinion m which gears with a pinion n' on the
upright shaft n; the latter is provided at its lower extremity with another bevel
pinion n gearing with the bevel-wheel b¹ for driving the said double screw-shaft.
The shaft n has the pinion n¹ secured to it by a key or feather on the shaft and a
groove in the pinion's boss, so that the said shaft will turn with the pinion n', but
at the same time will slide freely up and down through the boss of the same, thereby
keeping the pinion n³ on the lower end of the said shaft in gear with the wheel 6¹
during the movements or changes of position of the screw b.
The same result is effected in the press shewn in Figures 3 and 4 by the
following means, that is to say: on the shaft h* is fixed a toothed pinion h³ and
radius arms or links o are fitted on the said shaft with a capability of turning
thereon. These arms are jointed to the arms p which are also jointed to the screw
shaft b. A toothed wheel q has its axis at the junction of the rods o, p, and gears
with the pinion h³ and with a wheel r on the screw shaft b. It is obvious that the
radius arms o, p, will permit the required movements of the shaft b to take place
while keeping the wheels h³, q, r, in gear with each other.
In Figures 5 and 6 we have shewn a modification of our Invention in which the
said improved frictional gearing instead of forming a part of the press is a separate
apparatus connected with the said press by a flexible band, belt, or rope, or by a
chains passing over a sprocket wheel s¹ on the shaft h*, and a similar wheel 82 on
the screw shaft b. Rollers t are arranged upon the ends of the screw shaft b,
and guide bars t¹are provided in contact with which the rollers t move in the
upward and downward movements of the follower e. These guide bars t¹ relieve
the screw shaft of the strain or pull of the chain or other power transmitting agent.
In this instance the follower moves upward in its compressing action.
In the operation of the press provided with our improved frictional gearing when
the follower e is to exert pressure on the goods or materials in the press, the friction
pinion g is caused to gear or work in contact with the outer or large frictional
surface or rim of the friction wheel h, and will then impart to the follower a slow
motion in the proper direction to force the same upon the material to be pressed,
and will exert a very powerful pressure thereon, but when it is desired to draw
back the said follower the friction pinion is caused to work in contact with the

page_text: inner or small frictional surface of the said wheel; the follower will then have a
comparatively quick motion in the opposite direction.
This capability of varying the speed of the machine affords the means for greatly
economizing time in the working of the same.
Moreover it will be obvious that by reason of the very slight movement required
to adjust the friction pinion g into contact with either of the surfaces of the friction
wheel, and thus reversing the movement of the follower we greatly facilitate and
accelerate the working of the press.
Having thus fully described our said Invention, and the manner of performing
the same, we wish it understood that we do not limit ourselves to the precise
details of construction and arrangement of the presses or machines shewn in the
accompanying Drawings, nor do we claim separately or irrespectively of their
combination with our improved frictional gearing any of the other parts of the
apparatus herein described and shown, but we claim,-
In and forming part of (or in connection with) a screw and lever press, such as
shewn in either of the forms or modifications illustrated in the Drawings, or a sub-
stantially similar press, the improved frictional gearing consisting of a wheel with
two surfaces and a pinion arrangement between them, which wheel or pinion is
provided or arranged in combination with means for adjusting the same, as and for
the purposes specified.
In witness whereof, I, the said John Haskins Ladd, for myself and on behalf
of the said Thomas Wrightson, have hereunto set my hand and seal, this
Twenty seventh day of January, in the year of our Lord One thousand
eight hundred and eighty.
JOHN HASKINS LADD. (L.S.)