IMPROVEMENTS IN MACHINE TOOLS SPECIALLY APPLICABLE FOR WORKING STONE
Year: 1885

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I ALFRED JULIUS BOULT of 323 High Holborn in the county of Middlesex,
Engineer do hereby declare the nature of this invention for "IMPROVEMENTS IN
MACHINE TOOLS SPECIALLY APPLICABLE FOR WORKING STONE (A cominunication
from Julius Richard Bock of Markt Redwitz, Bavaria, Engineer) and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :—
This invention can be readily applied to an ordinary lathe or a planing machine
with slight modifications, it consists essentially in giving to the tool a very rapid
forward and backward movement whilst the work makes a slight forward move-
ment when the tool retreats, the latter is required to prevent the tool being ground
off or chipped out.
Figure 1 shows front elevation of a lathe fitted with these improvements.
Figure 2 is a plan of the same.
Figure 3 side elevation.
Figure 4 transverse section on line J K of Figure 1.
On an ordinary lathe A the cross slide C of the slide rest B is fitted with another
slide or carriage D which carries the tool a and which is actuated by an eccentrically
mounted shaft b revolving at a speed of say about 100 revolutions per minute.
The eccentric shaft 6 is of about the same length as the central part E of, the
slide rest B; it turns in a guide or arm F of the tool carriage D and has its
bearings in two arms co screwed onto the central part E see Figures 1, 2, 3 and 4.
The eccentric shaft or spindle is driven off a shaft & having at its end special
cone pulley e (Figures 1 and 2) and by means of the chain wheels f g and toothed
wheels hi. The chain wheel f which has a recess moves with the arm K under-
neath the slide B (Figure 1) or in other words when the slide moves, the wheel
travels on the shaft d whereon a long feather is provided.
The chain n drives first the chain wheel g which is firmly united with the
toothed wheel h. These two turn on journal o running in an arm 7 (which swings
round shaft d) and passing through an arm m being thereby jointed to the extended

page_text: journal p of the eccentric shaft b. On the journal p the fly wheel q is also mounted
as well as a toothed wheel i engaging with the toothed wheel h and serving to
transmit motion to the shaft b; see Figures 1, 2, 3 and 4.
The slide may in consequence of this arrangement be adjusted in any direction
whilst the work is going on, and without stopping the lathe, the same as any other
slide rest. The reciprocating tool will consequently work with the same certainty
as a fixed one.
The rotation of the work is not effected continuously as in ordinary lathes but
intermittingly the advance always taking place at the moment when the tool
moves backward so that the tool is not ground away or chipped. This motion is
effected by means of the face plater the periphery whereof is cut into helical teeth
engaging with a helical pinion S. The latter is, together with a pinion u keyed on
an arbort having its bearings at x and y; it receives its motion by a cam wheel v
on the shaft d. At each rotation of the latter the pinion is moved one tooth
forward thus causing intermittent motion of the arbor t, the helical pinion S and of
the face plater which carries the work, see Figures 1, 2 and 3.
The automatic motion of the slide rest B along the bed A is effected by the
guide spindle w which receives its motion from the shaft d by the gear wheels o¹
y', and ¹ and the motion may be in the proportion of say 1 to 50.
Otherwise this lathe is like any other fitted with back centre a chuck and a
large cone pulley &c. When the piece that has been turned is to be ground or
polished, the small cone pulley e is thrown out of gear. The bearings x and y
together with the arbor tare moved towards the headstock and the face plate
thereby disengaged from the screw 8, the large cone pulley may then be set to
work by means of the usual overhead gear and the grinding and polishing are
effected in the usual manner.
Having now particularly described and ascertained the nature of my said
invention and in what manner is to be performed, as communicated to me by my
foreign correspondent I declare that what I claim is
1. In machine tools for working stone the employment of a reciprocating tool a
driven by an excentric shaft b. the tool being mounted in a slide or carriage D.
mounted on the top of the usual slide rest B.
2. The method of driving the excentric shaft b. by means of the chain gear and
toothed gear, connecting the same with the shaft d, substantially as described and
illustrated in figs. 1. 3 & 4 and allowing the tool so to be adjusted at will.
3. The guiding or movably fitting of the chain wheel f and of the lower eye or
end of the arm on the shaft d by the arm K of the slide rest B.
4. The intermittent motion or rotation of the work during the return motion
of the tool a by the face plate r. having helical teeth and the helical wheel a
mounted with the pinion u. on the movable arbor t. and receiving motion from the 4
shaft d through the pinion v. in such a manner that when arbor is thrown out of
gear and the large cone pulley e' into gear the work may be ground or polished in
the usual manner.
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