Improved Silent Driving Gear and Automatic Stops for Slide Rests and Lathes.
Year: 1888

page_text: Date of Application, 6th Dec., 1888
Complete Specification Left, 6th Sept., 1889-Accepted, 26th Oct., 1889
PROVISIONAL SPECIFICATION.
Improved Silent Driving Gear and Automatic Stops for Slide Rests
and Lathes.
We, JOHN JACOB HOLTZAPFFEL of 64 Charing Cross Engineer & GEORGE
WILLIAM BUDD of 127 Long Acre in the County of Middlesex, Engineer do hereby
declare the nature of this invention to be as follows:-
In turning various work in the Lathe it is frequently desirable to give the tool in the
Slide Rest or Lathe a slow and regular traverse and this can be done more perfectly
mechanically than by hand. In ornamental turning, that is, in ornamenting turned
works produced in the Lathe, it is frequently necessary to arrest the tools in the Slide
Rest at various fixed points on the work as in "fluting" and these two objects wo
obtain in the following manner. Firstly in order to cause the tool to traverse, that is
to move along the Slide Rest we attach to one end of the mainscrew a tangent or
worm wheel of a suitable number of teeth and cause this to revolve by the motion of
an endless or tangent screw of a suitable number of threads which is caused to gear
into the worm wheel; one end of this tangent screw carries a pulley of suitable
construction for use with a band of catgut, leather or any other suitable material.
The tangent screw put in motion by means of the band causes the wheel to turn and
give the mainscrew of the lathe or Slide Rest the required revolution to make the tool
Slide move slowly in the required direction.
The endless tangent or screw is mounted in a carriage, which carriage has the power
of partially rotating on a centre placed towards the end of the carriage next the pulley
and it is so arranged that when the screw and worm wheel are in gear (the screw
being generally placed below the tangent wheel) the carriage and screw are held up
to the work by a catch that usually takes the form of a hook the hook is mounted
on a rod or pivot and has its inside edge or that which is in contact with the screw
carriage of a peculiar form and the pivot is so constructed that by means of a cross
bar or other suitable mechanism any movement in either direction given to a
horizontal rod by a stop in the tool carriage or Slide Rest coming in contact with
stops on the rod causes the hook to move on its pivot and allow the screw carriage
to partially rotate on its center, and to cause the tangent screw to be thrown out of
gear with the worm wheel.
We can apply our invention to any Slide Rest or Slide Lathe and by it can obtain
a regular movement of the screw to which our apparatus is applied-We can arrest
the traverse of the tool, either in the Slide Rest or Lathe at any precise point where
it may be desired, and our apparatus when in work is absolutely silent.
In connection with the above we can use two or more springs to cause the tangent
screw to be thrown out of gear when released by the catch and cause the catch to be
returned to its place to hold the screw carriage in gear and we apply a stop or stops
to determine the extent of the partial rotation of the tangent screw carriage.
We can attach our apparatus permanently to the Lathe or Slide Rest or by a
simple arrangement we make it so that like various other turning apparatus it can be
removed at pleasure.
Dated this 5th day of December 1888.
JOHN JACOB HOLTZAPFFEL.
GEORGE WILLIAM BUDD.

page_text: COMPLETE SPECIFICATION.
Improved Silent Driving Gear and Automatic Stops for Slide Rests
and Lathes.
We JOHN JACOB HOLTZAPFFEL of 64 Charing Cross in the County of Middlesex
Engineer and GEORGE WILLIAM BUDD of 127 Long Acre in the County of Middlesex
Engineer do hereby declare the nature of our invention for IMPROVED SILENT
DRIVING GEAR AND AUTOMATIC STOPS FOR SLIDE RESTS AND LATHES and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
In producing various works in the Iathe, it is frequently desirable to give the tool
in the Slide Rest or the tool holder or carriage of a traversing or Slide Lathe or in
the case of a shaping machine, the work itself, a slow and regular traverse and this
can be done more perfectly mechanically than by hand-It is also desirable to be able
to arrest the traverse of the tool or of the work at any required point on the work,
and these two objects we obtain in the following manner. In order to cause the tool
or work to traverse, that is to move along the slide of the Rest, or the Lathe or the
Shaping Machine, we attach to one end of the mainscrew of the slide, a tangent or worm
wheel of a convenient number of teeth, and cause this wheel to revolve by the motion
given by an endless or tangent screw of a convenient number of threads corre-
sponding in pitch to the teeth or worm of the tangent wheel-The precise pitch of the
tangent screw and the diameter of the tangent wheel, we determine as the motion to
be given to the mainscrew is required to be quicker or slower a point that also
influences the size of the Driving Pulley hereafter mentioned. At times we employ
multiple threaded screws, or those in which two or more threads of similar pitch, are
formed around the same shaft, for the tangent screw-At one end of the tangent screw
we place a pulley of convenient construction, for use with a band of catgut, leather, or
any other suitable material.
The tangent screw put in motion by a band from the shaft conveying the power,
causes the pulley to revolve and with it the tangent screw, which in turn gives motion
to the tangent wheel attached to the mainscrew of the slide, causing it to revolve, and
giving the required traverse to the tool or work.
The endless or tangent screw is mounted in a carriage which has the power of
partially rotating on a pivot or centre placed towards the end of the carriage next the
pulley, and it is so arranged that when the tangent screw and worm wheel are in gear,
the screw being generally placed below the tangent wheel, the carriage and screw are
held up to their work by a catch that usually takes the form of a hook, which is
placed so that its support is given to the tangent screw carriage, at the other end to
that occupied by the pivot-The catch or hook is fixed on a rod or pivot supported by
attachments to a plate that carries the apparatus and which at times, in the case of
Slide Rests, we make removeable, as hereafter describod, but which may be permanently
attached to the machine to which our apparatus is applied. The inside edge of the
catch or hook or that which is in contact with the screw carriage is of a particular
form, that is, it is a portion of a circle of which the centre coincides with the centre of
the rod or pivot to which it is attached-At one end of the pivot or rod, usually at the
end nearest the driving pulley, and remote from the catch or hook, we place a small
bar or crosspiece of a convenient form, which usually stands vertically for giving
motion to the rod or pivot as hereafter described-Along the slide, and supported in a
convenient manner, usually by passing through the fixed or moveable, plate before
mentioned, and through the stop on the traversing or sliding part of the Rest, Lathe
or machine, we place a rod that carries near one end of it a piece of metal placed at a
suitable angle, that carries two pins, so arranged, that one pin engages on one side
of one of the ends of the crosspiece or bar on the pivot, and the other pin with the
opposite side of the other end of the crosspiece or bar-This rod, usually of the
whole length of the slide to which our apparatus is applied, passes through a stop or
projection on the traversing portion of the Lathe Slide Rest or machine as, before

page_text: mentioned, and also carries two adjustable or sliding collars that may be fixed at any
required point by means of clamping screws-These collars are placed in the positions
necessary when it is required to arrest the traverse of the tool or work and when
the projection above mentioned, comes in contact with either one or the other of the
collars it causes the rod to slide, and with it the piece carrying the pins, which come
in contact with one or the other end of the cross piece or bar at the end of the pivot
carrying the catch or hook, causing the pivot to rotate and with it the hook, and
when the hook as rotated a sufficient distance, it disengages from the tangent screw
carriage, which then rotates a sufficient distance to allow the tangent screw to leave
the tangent wheel which of course instantly stops, and consequently the mainscrew
and tool carriage or work stand still. The precise distance the tangent screw carriage
is allowed to rotate is regulated by a stop-The object of making the inside end of the
hook as described is that while the rod with the collars is sliding the necessary
distance to disengage the hook, the screw may be kept in contact with the tangent
wheel, and that no rotary motion shall be given to the tangent screw carriage until
the instant the book disengages from it, when the screw carriage rotates on its centre,
and the screw is thrown out of contact with the wheel suddenly-In order to assist.
the tension of the band which causes this result generally, we. sometimes employ a
spring of a flat or other convenient form to cause the tangent screw carriage to
rotate.
In the case of a Slide Rest it is convenient and frequently necessary to be able
to remove such Apparatus as described to make room for other, and in order that
we may be able to do this, we mount the whole of the moveable parts, the tangent
Screw and carriage on one side, and the pivot or rod & the hook or catch on the other
side of a suitable metal plate, having an aperture of the shape of the slide of the Rest
and by withdrawing a filling piece on one side we can remove our apparatus and
replace it, as desired by removing one screw of a convenient form or if we desire it
we can permanently attach the plate to the end of the slide of the Slide Rest, Lathe
or other machine.
A reference to the drawings in which like letters represent like parts will help to
explain the construction of our invention.
The apparatus is shown, as an illustration, as applied to a Slide Rest. Figure 1
is a front elevation showing the plate a, shaped out to fit the slide p, and
having a removeable piece at one side b, retained in its place by the screw h, &
when the screw is taken out, the piece may be removed and the plate a and
its attachments can be drawn off sidoways from the slide-The plate has in front
a carriage c, carrying the tangent screw gearing into a tangent wheel g (shown in
this view as a circle) mounted on the end of the mainscrew -This carriage for the
tangent screw has a projection which forms its centre or pivot, at the back, which
passes nearly through the plate a and is secured by a screw. The tangent screw is
driven by the pulley e, shown in this case of the form for use with a lathe band, and
the screw projects through it as a square to receive a key or winch handle when
required The carriage is pivotted as mentioned above at the end nearest the pulley e,
and the screw is held in gear by the catch or hook m which when withdrawn allows
the carriage to rotate until it comes in contact with the stopin-Figure 2 is a side
elevation showing the end of the pivot or rod k and the crosspiece or bar and has
also a portion of the sliding rod and its attachment carrying the pins, indicated to
show the relative position of the parts-It will be seen that the rods passes
through the plate a and can be clamped by the screw when desired-Figure 3 is a
back elevation showing the position of the pivot of the carriage d and the catch m,
retained in its place by the spring u, under the influence of which it returns to its
place after having been withdrawn by the rotation of the rod k. Figure 4 is a plan
of Figure 1-Figure 5 shows a portion of the sliding rods; having the adjustable
collars with clamping screws tt, and the attachment carrying the pins oo, which
engage with the cross piece l, l,-Figure 6 is an end elevation of Fig. 5 showing the
position of the pins o, o, and also a flat, made on the end of the rod, that passes
through the plate a so that when the screw is screwed down sufficiently the rod

page_text: cannot turn round although it is free to slide. Figure 7 is a plan of the Tangent
screw carriage showing the pivot:d-and-Figure 8 shows one of the adjustable collars
in side & end elevation. This apparatus is manipulated in a precisely similar
manner to the Automatic Apparatus of J. 1. Ashton Esq., described at length in
Volume V. of Holtzapffel's Turning and Mechanical Manipulation:". It will be
scen from the above description and drawings that this Apparatus has many advan-
tages, over the Apparatus as usually constructed By means of a tangent screw
driven by a pulley and band without any gearing we can give a slow regular move-
ment to the screw of a Slide Rest, Lathe or shaping machine, arresting the movement in
either direction at any precise point we may desire-The action of the Apparatus is
noiseless and we can remove the Apparatus easily and without deranging its parts by
the withdrawal of a single screw, and that when the tangent screw is thrown out of
gear the tension of the band as usually applied from an overhead motion or shaft,
assists the action instead of acting in a contrary direction, as is the case in the
various apparatus now in use with moving tangent screw carriages, not using gear
wheels.
We are aware that tangent screws and wheels are and have been used to drive the
mainscrews of Slide Rests and other machines, and we do not claim them, nor the
use of a moveable carriage carrying the tangent screw (except as described in our
3rd claim) nor the use of a sliding rod with adjustable collars, many arrangements of
which are fully described in Volume V. of Holtzapffel's work before mentioned,
except as applied to our Apparatus.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is ;-
1. The construction in combination of an Apparatus for giving a slow regular
motion to the screw of a Slide Rest having the power of arresting the motion in either
direction, and being capable of being removed at will, substantially as above
described.
2. The construction in combination of an Apparatus for giving a slow regular
motion to the screw of a Slide Lathe or Shaping machine having the power of
arresting the motion in either direction substantially as above described.
3. The construction of a carriage for carrying a tangent screw, having the pivot on
which it rotates placed on the side nearest the driving pulley in manner and for the
purposes substantially as above described.
Dated this 6th day of September 1889
JOHN JACOB HOLTZAPFFEL.
GEORGE WILLIAM BUDD.