Improvements in Engraving Machines.
Year: 1894

page_text: Date of Application, 30th Mar., 1894-Accepted, 2nd June, 1894
COMPLETE SPECIFICATION.
Improvements in Engraving Machines.
We, WILLIAM TAYLOR, THOMAS SMITHIES TAYLOR, and HERBERT
WILLIAM HOBSON, all of Slate Street, Leicester, in the County of Leicester,
Scientific Instrument Makers, 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:-
This invention relates to machines in which a revolving drill guided by one arm
of a pantograph engraves a copy of a design or pattern along which a tracing
point carried by another arm is guided. We shall describe these improvements
referring to the accompanying drawings.
Figure 1 is a side view, Figure 2 is an end view and Figure 3 is a plan of the
upper part of an engraving machine according to this invention.
Figures 4 and 5 are respectively side and end views partly in section of the
feeding gear for the drill.
Figures 6 and 7 are respectively side and end views and Figure 8 is a plan of a
chuck for holding cylindrical or other round objects to be engraved on.
Figures 9 and 10 are respectively a front view and a section of a gauge wheel
for circular work.
Figures 11 and 12 are respectively a plan and side view of a circular table for
the pattern.
Figure 13 is an elevation showing the arrangement for copying to the same scale
as the pattern.
Figure 14 is a section of arrangement for feeding the drill electrically.
Figure 15 is a section and Figure 16 a front view of a'modified arrangement for
electrical feed.
On a column A of convenient height we provide a slide bed a on which we fit a
slide a'. On this slide we pivot at a² a pantograph or parallelogram of jointed bars,
one of its sides being extended as an arm B carrying the tracer b. The side C
opposite to B carries a slide c to which is connected the bearing of the drill G, and
the side D which connects the sides B and C is fitted to slide in a guide d which
can turn on the pivot a². By sliding the bar D to various positions in the guide d,
and c to various positions proportionally on-the bar C, the scale of the copy can
be varied in the usual way, the centres of the tracer b, the pivot a² and of the
drill being always in one straight line. The bars C and D are suitably graduated.
The slide a is also graduated and when c is shifted along C, and D along d, the
slide a is also moved along a so that the axis of the drill spindle G remains
always in the same position when the tracer 6 is in the central or zero position
shown in Figure 3.
A table on which the pattern or design to be copied is fixed, is mounted on a
pivot on which it can be turned one quarter round, its movement being
limited by adjustable stop screws 6263, so that it can be clamped by a nut on its
pivot bolt b, either in the position shown or in a position at right angles to it as
indicated by the dotted lines in Figure 3. A slide rest E having longitudinal,
transverse and vertical movements, is fixed on the column A, and on its upper
face is fixed the plate or other flat object on which the copy is to be engraved.
When the object to be engraved is of cylindrical or other round shape the chuck F
shewn in Figures 6, 7 and 8 has its base f bolted on to the table of the slide
rest E. The chuck has a disc on the face of which is fixed the object to be
engraved. This disc is pivotted by a pin fs in the centre of a disc f2 so that

page_text: it can be turned round. The pin has fixed on it a collar and through the
centre off passes a sleeves enclosing the pin f. This sleeve is fitted with a
key so that it can slide in but cannot turn, its rear end is screw threaded
and is engaged by a nut with a handle by pushing down which the sleeve ƒ³
is screwed back against the collar thereby drawing the disc f back against
the face off so that it is firmly clamped in position. By raising the handle fe
the disc is released and can be turned. The disc has integral with it a
double circular segment f' which can slide along a circular segmental guide f³
projecting up from the base f. The disc f carrying f¹ can be turned more or
less on the horizontal axis of the guide f" and can be clamped by a nut f³, the
face of being thus presented in a vertical or in a horizontal plane or at any
intermediate inclination. On the pivot pin f³ is clamped by a nut a notched
disc with the notches of which a spring pawl f1 can engage so as to hold
the disc in various positions as it is turned round on its axis f³. It is con-
venient to have a number of discs f having various numbers of notches, any
one of these being put on f³ to suit the division of the circular piece, fixed in fi,
that has to be engraved.
When work has to be done for which no disc f10 is adapted it is convenient to
employ, instead of the divided disc f, a gauge wheel W such as is shown in front
view in Figure 9 and in section in Figure 10; the rim of this wheel is slit at w and
has fitted within it an elastic spring ring w. A strip of paper or other flexible
material can be put round the circumference of the wheel the ends of the strip
being both passed through the slit w and the ring w³ can be then turned round
until its end reaches a stop at 03, thus clamping the ends of the strip. This
strip having been marked (with lines to be read against the edge of the pawl) for
certain engraving work can be taken off the wheel W and put aside to be used
again when similar work has to be executed.
Having, as stated above, made provision for always bringing the axis of the
drill spindle into the same vertical line when the tracer is in its zero position not-
withstanding the alteration of parts to vary the scale of the copy, we prefer to
make the chuck base f so that when it is fixed on the slide rest E with its right
hand edge close against the vertical face of the slide rest, the axis of the disc f¹
is vertically below the axis of the drill spindle.
When the pattern to be copied consists of letters or other designs which are to
be successively brought to the zero point for the tracer b, we remove the rectangular
table band fix in its place a circular table 6, shown in plan in Figure 11 and in
elevation in Figure 12. It is fixed by the bolt so that a point z upon its face
coincides in position with the centre of the bolt 6 and therefore with the position
of the tracer 6 as shewn in Figure 3 corresponding to what may be termed the
zero position of the drill. The circular plate 6 is divided at its edge by notches
engaged by a spring pawl 67 so that it can be turned round a pin 6 to bring
successive letters or other designs round to z.
When the engraving has to be made to the same scale as the pattern, we remove
the slide a and the pantograph, leaving the drill bearing still carried on the
arms h h¹. On the top of h we fix by a screw a U shaped bracket L which
carries a tracer adjustable in height. We also bolt on a the head of the column,
a stand on which we mount the plate 61 carrying the pattern. On now moving
the tracer over the pattern, which is stationary, the drill moves with it copying
to the same scale as the pattern.
The drill spindle G has on it a pulley 9 round which the driving band is led
from a pair of guide pullies gl mounted in a fork which is steadied by a link g³
connecting it to the column A and by a stay rod g* connecting it to the bearing
of the drill spindle, along which rod the fork 92 can be slid to tighten the band.
The bearing of the drill spindle is formed in a boss H projecting from a deep
bracket which is jointed to a deep link pivotted to an arm h² projecting up
from the top of the column A. Thus, while the jointing of h to hand of ¹ to h³
allows freedom of motion to the drill spindle in the horizontal plane, the boss H is

page_text: steadied against any vertical movement or oscillation. The feed of the drill is
effected in the following manner. The bearing of the drill spindle G is formed in
a sleeve K which can slide vertically in the boss H. In a collar k at the top of
the sleeve is adjustably fixed a nut k¹ for a screw threaded sleeve ³ from which
projects a horizontal pink between two vertical pins, one of which 8 projects down
from the nut k¹ and the other from the collar k." A milled hand wheel k has the
lower part of its spindle projecting down through the sleeve k², which is clamped
on it with certain friction by a nut and elastic washer k, and has the upper part ke
screw threaded to work in the boss of a bracket projecting from h. The pitch of
the screw thread on k² is greater than the pitch of k. The edge of the nut k¹ is
graduated so that it can be turned more or less round from the position shown and
clamped in the collar k by a screw k. By thus turning the nut k¹ the pink is
moved away from k³ allowing the sleeve k² to turn to an extent determined by
the setting of the nut k'. If ¹ be in the position shewn so that the pin k³ is
engaged between the two vertical pins, then the sleeve 2 cannot turn and con-
sequently, on turning by hand the wheel k*, the screw alone operates, moving the
sleeve K and drill spindle G up or down according as k is turned in the one
direction or the other. In this case, as the sleeve k² is kept stationary, the spindle
of the wheel k* merely turns within it subject to the frictional resistance due to
the nut and washer . But, when the pin k³ is moved a certain distance away,
from leaving the sleeve k² free to turn so far round, then on turning the wheel k
the sleeve K and drill spindle G are raised and lowered to an extent determined
by the difference in pitch of the two screw threads k² and k and the part of a
revolution through which the sleeve 2 is turned as determined by the position of
the pink. In this way the depth to which the drill enters the work is determined
by the setting of the nut k¹ more or less round. If, for instance, the nut k¹ be
set so that the pin is turned away from ³ to the extent of a quarter of a
revolution, and if the hand wheel k be turned until k³ meets k³, the drill then just
touching the work, then on turning back the hand wheel while the screw ke
tends to raise the drill, the screw sleeve k² tends to a greater extent to lower it,
and the drill is thus fed gradually downwards until the pink is stopped after.
having turned the quarter of a revolution backwards, and then the screw ke alone
acts, raising the drill. The screw may be used alone for feeding, the sleeve k²
being in that case prevented from turning by its pin being engaged between the
two vertical pins. When the feeding is effected in this manner, we provide an
adjustable stop k to prevent the sleeve K and drill G from being screwed down
beyond the distance to which the stop is adjusted.
The feed may also be effected electrically as we shall describe referring to Fig. 14
which is a vertical section. To the sleeve K which slides in the boss II we attach
a frame M which carries within it an electro magnet m attached to its upper
limb. Through this electro magnet passes a spindle m' which terminates above
in a screw that is worked in a screw threaded hole in the bracket of h by turning
an iron hand wheel m². On the lower limb of the frame M centrally under the
spindle m¹ is a screw stop m³ which, can be delicately adjusted up or down by a
graduated head m*.
The rest on which the work to be engraved is fixed or the work itself, which is
of metal, is insulated from the machine and connected by a conductor to one
terminal of a battery or other source of electricity, the other terminal is connected
to the one end of the coil wire of the magnet m, the other end of the coil being
connected to the frame M.
Having adjusted the stop m³ a certain distance down from the end of the
spindle m¹ which distance is to determine the depth of the engraving, the wheel m²
is turned by hand. screwing down the spindle and lowering the wheel from the
magnet until the spindle m meets the stop m³. Continuing to turn the wheel m²
the whole frame M and with it the drill spindle and also the magnet are lowered,
the wheel m³ continuing to maintain the same distance from the magnet as that
determined in the first instance by the setting of the stop m³.. But,. as soon as the

page_text: drill touches the work, an electrical current is transmitted through the magnet
coils, and the magnet is attracted down to the iron wheel m³ feeding the drill into
the work until the magnet reaches the wheel.
A modified arrangement of electrical feed is shewn in vertical section Fig. 15
and front view Fig. 16. In this case the soft iron collar k of the sleeve K is made
to form the core and shell of an electromagnet m. The feed screw n has integral
with it a disc n¹ which has a notch at the edge and is enclosed within a milled
ring n² forming a hand wheel.
Under this is another milled hand wheel n³ having within it a disc n jointed
at its edge to n³ by a spring hinge which usually holds n' up so that a stud upon its
opposite edge is engaged in the notch of n. On the hand wheel n³ there is a
stop n projecting upwards and on the ring n² there is a stop n projecting down-
wards; the chamfered inner edge of the ring n has a zero mark, and the upper
face of the disc n' is graduated, and the ring n² can be turned round any desired
number of the divisions according to the desired depth of the engraving, separating
more or less the stop n from n³, in which position the ring n² is clamped to the
disc n' by a setting screw n'. The metal to be engraved being insulated, and it
and the coil of m being connected to a source of electricity, as in the arrangement
Fig. 14, the operator turning the ring n² lowers the sleeve K and all carried on it
until the drill touches the work, closing the circuit of the magnet m which thereupon
attracts its armature, the hinged disc n', the stud of which is thus withdrawn from
the notch of n¹. The operator continues to screw down until the stop n meets n³,
and now, as the hand wheel n³ is firmly held by the magnetic attraction on n¹ the
drill cannot be fed farther down. Thus the depth of the engraving is determined
by the number of divisions through which n² is turned.
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. An engraving
with reference to .
2. Mounting the
maintain the axis of the
of the table.
chine constructed and operating substantially as described
to 10 inclusive.
413
raph and the pattern table on a slide, adjustable to
lways in the same position when the tracer is at zero
3. Supporting the guide pulleys of the band by a steadying link and stay rod.
4. The chuck for circular work constructed and operating substantially as
described with reference to Figs. 6, 7 and 8.
5. The gauge wheel for flexible band, substantially as described with reference
to Figs. 9 and 10.
6. The circular pattern table, arranged and operating substantially as described
with reference to Figs. 11 and 12.
7. The appliance for copying to same scale as pattern, substantially as described
with reference to Fig. 13.
8. The feed apparatus substantially as described with reference to Figs. 4 and 5.
9. The herein described method of determining the depth of the engraving by
providing for the feed screw of the drill an adjustable stop actuated by an electro
magnet having its coil in a circuit which is closed by the contact of the drill with
the work.
10. The electrical feed arrangement described with reference to Fig. 14.
11. The modified electrical feed arrangement described with reference to Figs. 15
and 16.
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