Improvements in Lathes for Making Screws and for Turning Generally.
Year: 1888

page_text: Date of Application, 24th Nov., 1888
Complete Specification Left, 12th Aor., 1889
Complete Specification Accepted, 8th June, 1889
Improvements in Lathes for Making Screws and for Turning
Generally.
We, EDWIN BENNETT of The Ferns, Woodberry Downs, Iron Merchant, and
EMILE JEAN PIERRE RAVET, Engineer, of 1 Northampton Row, Exmouth Street,
Clerkenwell, both in the County of Middlesex, do hereby declare the nature of this
invention to be follows:-
The invention has for its object improvements in lathes for making screws and
for turning generally.
We will describe our invention as applied to a lathe in which the "hed" consists
of a single central bar supported by end standards.
Our invention relates, first, to means for facilitating the shifting of the driving
straps from either of two outer loose pulleys to a central driving pulley, so as to
enable the workman to change the direction of motion of the spindle, or to stop the
same, at his will, without necessitating his leaving his position opposite the work.
For this purpose we fix on the side of one end of the "bed "a guide, in which we
place two slides, one carrying a fork to act on one driving strap, the other carrying a
fork to act on the other strap.
One of these slides is acted upon by a spring to keep it normally towards the right
end of its guide, and thereby keep its corresponding strap on the loose pulley
situated on that side of the fixed pulley; the other slide has connected thereto
a Llever, the axis of motion of which is carried by a suitable part of the frame.
One arm of this lever is provided with a handle placed in convenient position to
enable the workman to operate the same without leaving his work, and the other
arm is connected with a treadle extending the length of the machine, or to any
convenient length, so that the workman can act on the same by his foot in whatever
position he is standing at the lathe. One of the slides is provided with a hook by
which it may be connected with the other and disconnected therefrom when desired.
By these means the workman can readily cause the spindle to run in either direction,
or, by disconnecting the two slides and acting on the lever by foot or hand, cause
it to ston.

page_text: The invention also relates to means for adjusting the cutting tools readily to the
centre of the work by mechanical means. For this purpose we formn the bottom of
the slot in the tool holder with an inclined face, and we fit a tapered false bottom or
tool supporting plate thereon, which is acted upon by a screw to cause it to advance
or recede, according as it is required to raise or lower the cutting tool.
The invention also relates to means for enabling cones of any degree of conicity to
be readily turned hy mechanical means. For this purpose we fit to the underside of
the "bed" a toothed rack, and we connect the same with the screw operating the
tool holder slide by gearing provided with change wheels, so that the tool holder will
be moved to and from the work in a given relation with the longitudinal travel of
the tool, according to the proportions of the wheels, for the time being, in use.
The invention also relates to means whereby we cause the power applied to advance
the tool, to act more nearly in a line with such tool than heretofore. For this purpose
instead of mounting the tool slide advancing screw, as heretofore, in an offset from
the slide, so that the screw passes loosely through a hole in the slide rest, we mount
the said screw in a recess in the side of the sliding tool holder as nearly underneath the
position of the cutter as possible.

page_text: Improvements in Lathes for Making Screws and for Turning
Generally.
We, EDWIN BENNETT of The Ferns, Woodberry Downs, Iron Merchant, and
EMILE JEAN PIERRE RAVET Engineer, of 1 Northampton Row, Exmouth Street,
Clerkenwell, both in the County of Middlesex, do hereby declare the nature of this
invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The invention has for its object improvements in lathes for making screws and for
turning generally.
We will describe our invention as applied to a lathe in which the bed consists of a
single central bar supported by end standards.
Our invention relates, first, to means for facilitating the shifting of the driving
straps from either of two outer loose pulleys to a central driving pulley, so as to
enable the workman to change the direction of motion of the spindle or to stop the
same at his will without necessitating his leaving his position opposite the work.
For this purpose we fix on the side of one end of the "bed," a guide, in which
we place two slides, one carrying a fork to act on one driving strap, the other
carrying a fork to act on the other strap.
One of these slides is acted upon by a spring to keep it normally towards the right
end of its guide, and thereby keep its corresponding strap on the loose pulley
situated on that sile of the fixed pulley. The other slide has connected thereto a
Llever, the axis of motion of which is carried by a suitable part of the frame. One
arm of this lever is provided with a handle placed in convenient position to euable
the workman to operate the same without leaving his work, and the other arm is
connected with a treadle extending the length of the machine, or to any convenient
length, so that the workman can act on the same by his foot in whatever position he
is standing at the lathe. One of the slides is provided with a hook or other means,
by which it may be connected with the other and dis-connected therefrom. when
desired. By these means the workman can readily cause the spindle to run in either
direction or, by disconnecting the two slides and acting on the ☐ lever by foot or
hand, cause it to stop.
The invention also relates to means for adjusting the cutting tools readily to the
centre of the work by mechanical means. For this purpose we form the bottom of
the slot in the tool holder with an inclined face, and we fit a tapered false bottom or
tool supporting plate thereon, which is acted upon by a screw to cause it to advance
or recede according as it is required to raise or lower the cutting tool.
The invention also relates to means for enabling cones of any degree of conicity

page_text: to be readily turned by mechanical means. For this purpose we fit to the underside
of the bed, a toothed rack, and we connect the same with the screw operating the
tool holder slide by gearing provided with change wheels, so that the tool holder will
be moved to and from the work in a given relation with the longitudinal travel of the
tool, according to the proportions of the wheels for the time being in use.
The invention also relates to means whereby we cause the power applied to advance
the tool to act more nearly in a line with such tool than heretofore. For this
purpose, instead of mounting the tool slide advancing screw, as heretofore, in an
offset from the slide, so that the screw passes loosely through a hole in the slide
rest, we mount the said screw in a recess in the side of the sliding tool holder, as
nearly underneath the position of the cutter as possible.
And in order that the said invention may be more clearly understood and readily
carried into effect, we will proceed, aided by the accompanying drawings, more fully
to describe the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front elevation, Figure 2 is a vertical cross section drawn on the
line 1. 1. of figure 1, and Figure 3 is a plan or top view of a lathe with our improve-
ments applied thereto. Figure 4 is a front elevation of the driving and reversing
gear, Figure 5 is a vertical cross section drawn on the line 2. 2. of figure 4, and
Figure 6 is a horizontal section drawn on the line 3. 3. of figure 4.
Figure 7 is a front elevation of parts of the driving and reversing gear, showing
the two strap forks disconnected, and Figures 8 and 9 are respectively an edge view
and an end view of the clip used for connecting and disconnecting the two strap
forks.
Figure 10 is a front elevation of slide rest and gearing for operating the same.
Figure 11 is a longitudinal section through slide rest and part of bed of lathe.
Figure 12 is a cross section of parts showing bed of machine, slide rest, gearing
for operating the same, and tool adjusting mechanism, and Figure 13 is a plan of
parts shown at Figures 10, 11 and 12.
Figures 4 to 13 are drawn to a larger scale than figures 1. 2. 3.
In all the figures like parts are indicated by similar letters of reference.
c is
a. a. are two end standards and a¹ is a cross bar forming the frame of the lathe,
bis the lathe bed, which consists of a single central bar, as is well understood.
the lathe spindle, which is fitted with two loose pulleys c¹ c² and with a driving
pulley ³.
The spindle c works in bearings in the standards of the head stock d and
is fitted with a chuck e, as is well understood, e. f. are two forks, which act
to shift either of two driving straps on to the driving pulley and the
other on to a loose pulley, or to shift both of them on to the loose pulleys. The
fork e is fixed to a slide e¹ and the fork to a slide f¹, both slides being mounted
to move to and fro between guides d' carried by the head stock d. The slide e' is
provided with a connecting link or clip e², which is formed with a slot es and
projecting lips e (see figures 7. 8. 9) to act in combination with a screw 2, fixed to
the slide, and a thumb nut fa capable of working to and fro on said screw, so
that when the slides el f¹ and nut f³ are in the position shown in figures 1, 3, 4, 5, 6,
the connecting link or clip is jammed by the nut f³, and the projecting lips e¹ fit
partly around the said nut, so as to connect the two slides ef firmly together.
When the nut is slacked back, the slide e', as shown at Figure 7, is capable of
independent motion, and the slide is, by the spring f4, retained at the right hand
end of its traverse with its fork fand strap in line with the loose pulley 2. When 5
the two slides are connected together, they are normally kept by the spring in the
position shown at figures 1. 3. 4, with the fork e in line with the driving pulley c³
and the fork in line with the loose pulley 2. To the slide e¹ is connected one arm g¹
of a crank lever, mounted on an axis fixed to the cross bar a', the other arm g² of

page_text: which is, by a link g³, connected to a treadle 94, extending from end to end of the
frame a, so as to enable the operative to shift the driving strap forks e. f by his foot,
at whatever part of the lathe he may be working. The arm g¹ of the crank lever is
extended above its connection with the slide e¹, and provided with a handle g³, to
enable it to be operated, when required, by the hand of the workman.
. are cutting tools carried by tool holders h² h² formed on, or fixed to, the
slide 3, and in order to enable the cutting tools to be readily adjusted to the centre
of the work by mechanical means, we form the bottom of the slot h* in the tool
holder with an inclined face, and we fit a tapered false bottom or tool supporting
plate thereon, which is in the form of an ordinary "gib," and is acted upon by a
screw to cause it to advance or recede, according as it is required to raise or
lower the cutting tool. The cutting tools h. ' are mounted in their holders with
their cutting edges in reverse positions, so that whichever of them is brought into
contact with the work, it shall be in a proper position for cutting, and the slide h³ is
provided with adjustable stop screws ', by which the depth to which the cutters h. h¹
will work can be easily regulated, as is well understood.
For the purpose of enabling cones of any degree of conicity to be readily turned
in the lathe by mechanical means, we adopt the following arrangement. We fit to
the underside of the bed b, a toothed rack i, and we connect the latter with the slide
screw by gearing provided with change wheels, which may be conveniently
arranged in the following manner. The slide rest k carries, in bearing brackets k¹
fixed thereto, a shaft or axis l, on which is fixed a toothed wheel, gearing into the
rack i, and a hand wheel by which the same can be readily rotated in either direction
as desired. On the said shaft is also mounted a toothed wheel 12, which gears into
an intermediate wheel m, the shaft or axis m¹ of which is adjustably fixed in the
slot of an adjustable arm m² mounted on a stud or axis m³; the intermediate wheel m
gears into, and gives motion to, a toothed wheel j¹ fixed on the end of the slide
screw j. The shaft or axis m¹ of the intermediate wheel m is made sufficiently long
to enable the wheel m to slide to and fro thereon for the purpose of keeping in gear
with the wheels 2 and ¹, and to enable the same to be moved out of gear therewith
when it is required to move the slide rest and slide independently of each other.
By these means the tools can be moved to and from the work in any given relation
with the longitudinal travel of the tools, according to the proportions of the wheels
for the time being in use for communicating motion from the toothed rack i to the
slide e¹.
Instead of mounting the slide screw ; as heretofore in an offset from the slide ³
working in a recess in the slide rest k, and therefore at a distance on one side of the
centre of the cutting tools, we mount the said screw j in a nut k² fixed to the slide
rest k, as nearly vertically underneath the position of the cutter as possible, by which
means we avoid any tendency of the tools h. h and slide h³ to assume an angular
position in relation to the slide rest k, and thereby secure good work and less wear
and tear on the guides.
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 combination with lathes, of means for shifting the driving straps from
either of two outer loose pulleys to a central driving pulley, so as to enable the
direction of motion of the spindle to be changed or to stop the same, substantially as
herein shown and described.
2. The combination with lathes, of means for mechanically adjusting the cutting
tools to the centre of the work, substantially as herein shown and described.
3. The combination with lathes, of a longitudinal rack, connected with the slide
screw by gearing provided with change wheels, for enabling cones of any degree of
conicity to be readily turned by mechanical means, substantially as herein shown and
described.

page_text: 4. Mounting the slide screw of lathes vertically, or nearly vertically, below the
cutting tool, substantially as herein shown and described.
5. In lathes for making screws and for turning generally, the various improve-
ments substantially as herein shown and described.
Dated this 19th day of Anril 1889
EDWIN
BENNETT.
EMILE. J. P. RAVET.
By Harris & Mills,
23, Southampton Buildings,
Agents.