Improvements in the Construction of Lathes.
Year: 1892

page_text: Date of Application, 25th Feb., 1892
Complete Specification Left, 24th Nov., 1892-Accepted, 21st Jan., 18º3
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Lathes.
I EUGENE CONRADY of Keighley Model Works, Keighley in the County of
York, Engineer, do hereby declare the nature of this invention to be as follows,
that is to say :-
It has for its object the production of turning lathes or like mechanisms that
shall perform their operations or functions more accurately and with greater
precision than do those as heretofore constructed.
To attain this object I construct the lathe-bed or longitudinal support for the
operating mechanism, so that its upper surface will be curved in cross section in
contradistinction to the forming of a level or flat surface as has heretofore been
followed. This curvature is an arc of a circle or portion of a cylinder of which the
centre lies in the centre line of the head and tail stocks or of which the axis
coincides with the axis of the lathe's spindles.
The surfaces of the head and tail stocks, tool rest or other fittings or parts
that are for contiguity with this curved surface of the lathe-bed are of a
correspondingly curved form being of course convex to fit into the concavity of
the lathe-bed.
By following this method of construction the accuracy of the work done or
produced does not depend upon the accuracy or truth in the relative positions of
so many bearing and guiding surfaces as does the work produced by lathes con-
structed as heretofore since provided that the parallelism of the spindle's axis
with the curved surface of the bed is secured any slight lateral play or
"side-
shake" of the tool holder or other parts will not in the least degree interfere with
their true and accurate operations on the material acted upon, by reason of the
curvature of the bed guiding the parts should there be any such lateral play to
move in a path parallel with the axis of the lathe's spindles, or in a path that is
equidistant from said axis or centre line of the head and tail stocks throughout its
entire length.
Dated this 24th day of February 1892.
EUGENE CONRADY,
Per Samuel Hey,
Agent.
COMPLETE SPECIFICATION.
Improvements in the Construction of Lathes.
I, EUGENE CONRADY of Keighley Model Works, Keighley in the County of
York, Engineer, 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, that is to say :-
It has for its object the production of turning lathes or like mechanisms that
shall perform their operations or functions more accurately and with greater
precision than do those as heretofore constructed.
In order that my said invention may be more readily understood I have hereunto
appended sheets of drawings illustrative thereof, to which, by figures and letters,
reference is made in the following description.
Fig. 1 is sectional end elevation of a lathe-bed, head-stock and tool-rest made in
accordance with my invention.
T
1
L
1

page_text: hereinafter described.
Fig. 7 is sectional side elevation of a lathe-bed with the head and tail stocks and
saddle or tool carriage applied.
Fig. 8 is sectional end elevation of a modified form of saddle and tool rest.
Fig. 9 shows the parts illustrated by Fig. 8 as seen from beneath.
Fig. 10 is a drawing in detail hereinafter explained.
Figs. 11 and 12 are sectional views illustrative of a modification in certain of the
parts shown by Figs. 1 and 2.
Similar letters and figures of reference indicate similar parts throughout the
several views.
To attain the object of my invention I construct the lathe-bed a so that its upper
surface a will be curved in cross section in contradistinction to the forming of a
level or flat surface thereon as has heretofore been followed. This curvature is an
are of a circle or portion of a cylinder of which the centre lies in the centre line of
the head and tail-stocks b and c or of which the axis coincides with the axis of the
lathe's spindles b¹, c¹.
The surfaces of the head and tail stocks b and c, tool rest d or other fittings or
parts that are for contiguity with the curved surface a' of the lathe-bed a are of a
correspondingly curved form, being of course, convex to fit into the concavity of
the said lathe-bed a. And in the case of the head and tail stocks b and c the
method of attachment to or of mounting them upon said lathe-bed a may be by a
projecting piece 2 entering a groove in the bed a as shown by Figs. 1 and 3 in
connection with which the usual block e and bolt fare employed, or a projecting rib a³
might be formed upon the curved surface of the bed a and the head or tail stock
made to take over such projecting rib as shown by Fig. 4. Or again flanges hh' may
be formed upon said head and tail stocks b and c to span the outer edges of the
bed a as shown by Fig. 5.
As to the fitting of the hand rest d upon the bed a, in respect of small lathes the
method shown by Figs. 1 and 2 is followed. Here the projecting lip k is made to
extend over the outer edge a³ of the bed a while the loose piece m is, by the bolt n,
made to press against the inclined outer edge a of the said bed a by which means
said hand rest d is firmly secured; and the bolt n is arranged to pass also through
the slot o' in the swivelling piece o so that at the time of securing the hand rest d
to the bed a this piece o is also firmly secured and that in any position its said
slot o may allow. In this part >> the tool-rest or tee p is secured by fitting
within the socket o² which is formed eccentrically with the bolt n by which means
it may be made to assume varied positions relatively therewith.
In larger lathes the pin having a part n² formed eccentrically thereon, the
same being rotated by the handle n³ and made to operate within the eye n' of the
bolt n, is employed instead of the screwed bolt above described, while the part m in
addition to abutting against the hand rest d at 2 is made to span the said part 2 which
thus tends to secure it from moving laterally when only loosely held by the bolt n.
The saddle d³ might be secured to the bed a by means of a projecting part d
passing through the slot or groove in said bed a for a spring r to be secured thereto.
Runners being mounted on this spring to relieve same from excessive friction in
its movements along the bed a.
Another method, and one that I preferably follow, of mounting the saddle d³
upon its bed a is illustrated by Figs. 8, 9 and 10. In this case the dovetailed
projection is formed on the saddle d to project into the groove of the bed a, the
under surfaces a' and a of which are bevelled or inclined to correspond with those
on the projection d. One side d² of this projecting part, is made to be loosely
inserted or laid over the part d' in order that by screws s s¹ it may be made
to press against the surfaces of the bed a as is from time to time found necessary to
take out the "play" and draw the saddle d closely to the bed a. In addition to
the screws & a spring t may be employed to press the part d² to take out the play
automatically.

page_text: By following the method of construction herein before described the accuracy of
the work done or produced does not depend upon the accuracy or truth in the rela-
tive positions of so many bearing and guiding surfaces as does the work produced
by lathes constructed as heretofore, since provided that the coincidence of the
spindles' axis with the axis of the cylindrical surface of the bed is secured, any
lateral play or
"side shake" of the tool holder or other parts will not in the least
degree interfere with their true and accurate operations on the material acted upon,
by reason of the curvature of the bed guiding the parts, should there be any such
lateral play, to move in a circle or circles around the centre line of the lathe or
around the axis of the spindles of said lathe. And to secure certain of these
advantages in connection with lathes wherein the strain from the work being done
or executed by the rotary motion of its spindles, is such as to tend to lift the spindle
bearings from off the lathe-bed a, they may be effected by following the same
principle of construction in the formation of the guiding surfaces, that is by
forming same in a circle around said spindle's centre, which under these circum-
stances would cause the guiding surfaces to be on the underside of the flanges v
(see Fig. 6) formed on said bed a in which case they would be convex instead of
concave, the concavity fitting same being formed on the overlapping parts of the
bearings b, this formation of the guiding surfaces being merely a transposition of
and a mechanical equivalent for those hereinafter described. When making use
of the formation of lathe-bed shown by Figs. 6 it will be necessary to employ an
additional guiding surface for the tool carriage, such guiding surface being
formed either on the edge of a projecting rib as that shown at a² Fig. 4 or on the
edge of the groove or slot in the lathe-bed as formed in the common and well known
manner.
In the foregoing description the common lathe alone has been the one referred
to, however it will readily be seen that this invention applies with equal advantages
to those known as screw cutting lathes, as also to those used for boring and like
operations in which latter case the work is held stationary on the bed while the
cutting tool revolves.
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. A lathe-bed having its surface curved in cross section substantially as herein
specified.
2. The combination of a lathe-bed curved in cross section with the head and tail
stocks formed to suit or correspond with same substantially as set forth.
3. The combination of a lathe-bed of the shape or form described with a hand
rest formed to fit same, together with an adjustable part for carrying the tee so
that its position may be regulated by the loosening or tightening of one bolt by a
screw or eccentric substantially as specified.
4. The combination of a lathe-bed of the form described and having a central
groove or slot with inclined edges, with a saddle made to fit same, and a loose
adjusting piece with or without adjusting spring substantially as herein set forth
and described.
Dated this 23rd day of November 1892.
EUGENE CONRADY,
Per Samuel Hey.
Agent.