Improvements in the Manufacture of Pitch Chains and other similar articles, and in Machine Tools and Apparatus to be used in such Manufacture.
Year: 1891

page_text: Date of Application, 25th Apr., 1891
Complete Specification Left 25th Jan., 1892-Accepted, 12th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Pitch Chains and other
similar articles, and in Machine Tools and Apparatus to be used
in such Manufacture.
I, JOHN ARMSTRONG SNOWDON, of Thirlwell House, Wolsingham, in the
County of Durham, Engineer, do hereby declare the nature of the said invention
to be as follows:-
These improvements relate more particularly to the manufacture of that class of
pitch-chain in which the middle portion or link is formed with four projections or
studs in one solid piece, the outside links being more or less of the usual shape, but
the said improvements are also applicable to the manufacture of other articles of
a similar character.
Instead of making the said middle links as stamped forgings, I use the material
in the shape of long bars; first planing them to a suitably shaped section, I next
pass them to slotting machines provided with special tools to cut them into ten or
twenty lengths at a time, more or less, two tools being used of an improved kind,
attached by a hinged joint to a tool bar slightly thinner than the cutter so as to
clear in splitting through the series of bars, no hinge pin is used, a simple spring
and V piece formed on the tool being sufficient to bring the cutter solid against
the bottom of tool bar each time the machine returns to the cutting position.
By this tool I am enabled to produce a much larger amount of work owing to the
higher speed at which the machine can be run, and the better cutting shape in
which the tool can be kept; it can be detached in a moment from the tool bar,
and weighs from one to two pounds against what has formerly required forty to
fifty pounds weight of steel.
The tool bar may be made of inferior steel costing much less than that from
which the cutter is made. This arrangement converts the cutting portion of the
tool from a vertical to a horizontal cutter; several of these cutters may be used on
one tool bar. The same type of tools is used for cutting a groove on each face of
a series of the pieces of material (previously cut off) leaving four. projections of
square section. Two, three, or more, tools may be used at this operation according
to the size of machine employed.
The next operation is to place one of the said pieces in a specially devised
machine which operates on opposite sides of the link and converts the projections
of square section mentioned above into projections of round section. The said
machine consists of two double geared lathe headstocks fixed upon a suitable bed
supported on iron or other standards. The piece to form the link is held by set-
screws and shoes in a cast steel chuck fastened by bolts to a crossplate which is
secured to the lathe bed. A stop pin is used in the chuck and three holes in the
crossplate divides the exact pitch between the centres of studs on the links, the
middle hole giving the centre between the studs; the headstocks are fitted with
sockets running in bearings into which steel spindles are fitted to work in a hori-
zontal direction by means of variable feed gear provided with self-acting and hand
motions. An arrangement is made to automatically throw the self-acting apparatus
out of gear at any point that may be desired. The spindles are fitted with
cylindrical boxes carrying a series of cutters to turn and face the projections or
studs both at base and ends; drills are also fitted to bore holes in the studs a
certain depth, thus enabling the four projections to be turned, faced and bored at
two operations only. If necessary, the chuck holding the link can be pushed aside
and two centring drills can be inserted in the cylindrical boxes to drill centres
between the two studs. The said machine can also be used as a self-centring

page_text: machine by using gripping jaws to hold the shaft, bolt, or other work, the said jaws
taking the place of the cast steel chuck already mentioned. For the outside links
the material is again planed in long bars to the finished sizes on two faces, then cut
off in batches in lengths with the same kind of hinged splitting tool as before
described; this is supplemented by a tool to part or split off the material in a
curvilinear direction both concave and convex instead of cutting the material away
in chips to obtain the proper shape.
I next bore the holes in an ordinary vertical drilling machine, at one operation
for the two holes, by means of an apparatus fixed on the table, carrying two
spindles actuated by a toothed wheel fixed on drilling machine spindle, gearing
into two similar wheels on the spindles carrying the drills operating on both holes
of the link at the same time.
Several links are next placed upon a mandrill fixed in the hole of the circular
table of a slotting machine, and finished round the curved ends by means of a
special slotting tool-box in which the tool is freed from rubbing against the
material on the return or up-stroke. The tool is held by two screws in a hinged
holder carried by a hinge-pin which passes through the holder and two jaws, the
latter being placed at an angle to its base in which respect it differs from other
tool holders of this type. The said angular position of the jaws causing the tool
to have a greater clearance on the return stroke both when cutting longitudinally
and transversely.
The tool holder is bolted to the bottom end of slotting machine ram, one of
the fixing bolts being also used as a pivot upon which the tool holder can be
moved round to whichever side is necessary to suit the direction in which the tool
is to cut, and to obtain the full advantage of clearance from the angular jaws. A
small spring acting near the non-cutting end of the tool brings the cutting end
to the proper position each time the return or non-cutting stroke of machine is
performed. In some cases a balance weight hooked on to the tool will answer the
same purpose.
Dated this 95th doxe of Annil 1901
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Pitch Chains and other
similar articles, and in Machine Tools and Apparatus to be used
in such Manufacture.
I, JOHN ARMSTRONG SNOWDON, of Thirlwell House, Wolsingham, in the
County of Durham, Engineer, do hereby declare the nature of the said invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement, reference being had to the accom-
panying three sheets of drawings, and to the letters and figures marked thereon,
that is to say :-
These improvements relate more particularly to the manufacture of that class of
pitch-chains in which the middle portion or link is formed with four projections or
studs in one solid piece, the outside links being more or less of the usual shape; but
the said improvements are also applicable to the manufacture of other articles of a
similar character.
Instead of making the said links as stamped forgings, I use the material in the
shape of long bars, first planing them to a suitably shaped section; I next pass
them to machines provided with special tools to cut them into a number of lengths
at one time. These special tools consist of cutters attached by a hinged joint to a
tool-bar slightly thinner than the cutters so as to clear in splitting through the
series of bars; no hinge pin is used, a simple spring and a V piece formed on the

page_text: cutter being sufficient to bring and guide the latter to a bearing against the cook
bar each time such cutter returns to the cutting position.
In the drawings, Figure 1 is a side elevation, Figure 2 an underside view and
Figure 3 a front elevation, of a tool-bar and cutters constructed in accordance
with this part of my invention, and suitable for use in a slotting machine, for
example.
A is the tool-bar, which may be made of inferior steel, costing much less than
that from which the cutters B are made. These cutters are formed with circular
parts E which fit accurately in corresponding holes in the flat part of the tool-bar,
and serve as hinge joints on which the cutters are free to turn to a limited extent.
The acting parts of the cutters extend through notches or openings cut from the
edge or end of the tool-bar into the aforesaid holes. The cutters are inserted into
the tool-bar from the side, and a V piece F formed on each of the cutters, takes
into a correspondingly shaped recess G in the tool-bar, and the cutter is thereby
kept central with the latter and prevented from slipping out sidewise therefrom.
The spring H forces the back B of the cutter to take a bearing against the
part B2 of the tool-bar in readiness for the next cut, but allows the cutter to turn
backward on its hinge part E as the cutting edge passes backwards over the work.
The part A of the tool-bar in which the cutters are mounted is somewhat thinner,
as shown, than the width of the cutting edges of the cutters B, in order to clear in
splitting through as above explained. The part A2 of the tool-bar is that by
which it is secured in the tool holder or tool box of the slotting machine.
This tool-bar and cutters may be mounted in a slotting or other suitable
machine and moved up and down or to and fro thereby like a saw, so as to operate
upon a piece of material fixed in position, suitable arrangements being provided for
feeding the tool-bar forward or down after each stroke, or the tool bar may be held
stationary while the material to be cut by it is moved to and fro, either the tool bar
being fed towards the material, or the material towards the tool bar after each
stroke, as may be most convenient or suitable.
Figure 4 of the drawings illustrates how the tool bar can be adapted to a planing
machine for the purpose, for example, of cutting off the rising heads of steel ingots.
A is the tool bar fitted with cutters B as above described, two of which are
shown adapted to cut in one direction and the other two in the opposite direction.
I is the bed of an ordinary planing machine, I' the planing table, 1* one of the side
standards, 13 the cross slide, I the bottom slide of the tool box, I' a standard
bolted to the end of the bed I and fitted with slides on which one end of the
tool bar A is guided while the other end is carried by the slide of the tool
box I*. I is the ingot from which the rising head is to be cut off, and which
is secured on the table I. It will now be understood that as the table of the
planing machine reciprocates it carries the ingot 16 to and fro under the tool
bar A, the cutters B cutting through the same as the tool bar is gradually fed
down by the traversing screws of the cross slide 13 and standard 15. These feed
screws may be connected together, so as to act in unison, by the shaft I' and
bevil wheels as shown.
By this arrangement of tool bar and cutters, I am enabled to produce a
much larger amount of work than by an ordinary slotting machine for example,
owing to the higher speed at which the machine can be run and the better cutting
shape in which the tools or cutters can be kept. The cutters can be detached
from the tool bar in a moment, and they each weigh, even for large work, only
one or two pounds against the 40 or 50 pounds required for large slotting tools.
These tools may also be used for cutting a groove or grooves on each face of
a series of the pieces of material (previously cut off) intended to form the middle
links of the pitch chain, so as to leave thereon four projections of square section ;
and two, three, or more, tools may be used at this operation according to the
size of machine employed. Such tools may also be used for cutting out the webs
of cranks and for a great variety of similar work.
In will be seen in Figures 1, 2, and 3 that the cutter at the end of the tool

page_text: bar has a diamond point and that the cutter behind it has a square nosed
cutting edge. I have found that with this arrangement much more work can be
done in a given time, than with square nosed tools alone, in splitting or parting
through material, as a diamond pointed or other similar cutter makes a preparatory
nick or groove in the material which relieves the pressure or wedging action that
takes place by the setting up in thickness and width of the cuttings made by the
square nosed tool. The diamond pointed cutter may be placed behind the square
nosed cutter, but in either case care should be taken that the diamond pointed
cutter should be arranged so as to cut the preparatory nick or groove before the
square noɛed tool begins to cut.
The next operation in the manufacture of the links of pitch chains is to place
the pieces, prepared as above, one at a time in a specially devised machine which
operates on opposite sides of the link, and converts the above mentioned projections
of square section into projections or studs of round section in the case of the middle
links, or bores the holes in the case of the outside links.
The said machine is illustrated in Figures 5, 6, 7 and 7ª, in which
Figure 5 is a front elevation,
Figure 6 a sectional elevation on line 1-1 of Figure 5 looking towards the right
in that figure,
Figure 7 a sectional elevation on same line but looking towards the left, and
Figure 7 a partial end elevation looking from left to right in Figure 5.
In
The machine consists of two double geared lathe headstocks A. A fixed opposite
to one another upon a suitable bed B supported on iron or other standards.
some cases four such headstocks may be employed arranged in two pairs as here-
after more fully explained. The piece C, which represents a middle link, is held
by set screws, as shown, in a cast steel or other suitable chuck D fastened by bolts
to a crossplate E which is secured to the lathe bed B. A stop pin F in the chuck
takes into either of three holes formed in the crossplate E at distances apart corre-
sponding to the centres of the studs on the links and to the centre between the
studs so that the chuck can be placed with accuracy with the centre of either stud,
or the centre point between the studs, coincident with the centre of the lathe
spindles. The headstocks are fitted with sockets or hollow mandrils G running in
bearings in the headstocks in the usual way, and into these mandrils are fitted and
adapted to turn therewith steel spindles H, which can be moved longitudinally by
means of feed gear provided with self-acting and hand motions, and automatic
devices for throwing the self-acting apparatus out of gear at any point that may
be desired. A suitable arrangement of such feed gear is illustrated in the figures
and consists as follows:-I is a cone pulley turning with the mandril G and driving
by a belt a corresponding cone pulley J on a shaft K which carries a bevil pinion L.
M is a short cross shaft having at one end a bevil pinion N which gears with the
bevil pinion L, and at the other end a worm P gearing with the worm wheel Q
loose on the shaft R but connectable therewith by means of the friction cone S
formed thereon against which the hand wheel U, which slides on a feather on the
shaft R, can be tightened up at pleasure by means of the handle T. The shaft R
carries at its other end a pinion V which gears with the wheel W the boss of which
forms a nut which works on the screwed end of the spindle H, the wheel W being
prevented from moving end wise by suitable bearings. X is a rod rocking in
bearings on the headstock. This rod carries an arm X' which is constantly drawn
by the spring X² towards the right in Figure 7. X³ is another arm carried by
the rod X and held by the spring X2 behind the sliding part of the clutch X* so as
to hold the same in gear with the other part of the clutch formed on the cone
pulley J, against the pressure of its spring X. The other end of the rod X carries
a finger or trigger X which can be adjusted and secured in any desired position on
the rod X. is a tappet secured on the spindle H and adapted to come in contact
with the finger or trigger X6 as the said spindle rotates and when it has been fed
forward to the required distance. It will now be understood that if the friction
cone S is free of the hand wheel U, the spindle H can be moved longitudinally

page_text: forward or backward at pleasure by turning the said hand wheel U; but if the hand
wheel U is tightened up against the friction cone S so as to connect the worm
wheel Q to the shaft R and the clutch X is held in gear with the cone pulley J
by the arm X, the revolution of the mandril G and spindle H will cause the
wheel W to rotate and to feed the spindle H forward automatically. And when
the said spindle H has been fed forward to the required extent, the tappet Y will
come against the finger or trigger X causing it to turn the rod X against the
action of the spring X' so as to withdraw the arm X³ from behind the clutch X
and allow the latter to be instantly thrown out of gear by its spring X thus
disconnecting the cone pulley J from the shaft X and thereby stopping the further
feeding forward of the spindle H automatically. When it is required to put the
clutch again in gear with the cone pulley J, the attendant pushes the clutch X+
home against the spring X, the spring X2 forces the arm X3 behind the clutch X*
and holds it in gear until again released by the trigger X.
The spindles H are fitted with cylindrical boxes H' carrying a series of cutters H²
to turn and face the projections or studs C₁ of the link both at base and ends.
Drills may also be fitted in the cylindrical boxes H' to bore holes a certain depth
into the studs, thus enabling the four projections or studs to be turned, faced and
bored at two operations only. If necessary the chuck holding the link can be
placed in position so that two centering drills inserted in the cylindrical boxes will
drill centres between the two studs on each side of the link to facilitate the turning
of the ends of the links in the lathe if required.
The same machine can also be used as a self centering machine by using gripping
jaws to hold the shaft, bolt or other work, the said jaws taking the place of the
chuck D above mentioned.
For the outside links, the material is planed in long bars to the finished sizes on
two faces, then cut off in batches in lengths with the tool bar and hinged cutters
above described. Similar hinged cutters, made concave, may also be employed to
part or split off the material in a curvilinear direction, either concave or convex in
large links or crank webs instead of cutting the material away in chips to obtain
the proper shape.
I next bore the holes in the outside links in an ordinary vertical drilling machine
at one operation for the two holes by means of an apparatus fixed on the table of
the machine and carrying two drilling spindles. These spindles are actuated by a
toothed wheel fixed on the drilling machine spindle and gearing into two similar
wheels on the spindles carrying the drills, which latter operate on both holes of the
link at the same time.
The holes may however be bored in the link-turning machine above described,
the links being fixed in the chuck D in the same manner as the middle links. The
rough holes are bored from one side of the link by means of a drill mounted in the
spindle of one headstock and the finished holes fine bored from the other side of
the link by a drill mounted in the spindle of the other headstock, or when four
headstocks are used two are employed to rough bore both holes at once and the
other two to fine bore both holes at once, both borings of each hole being effected
at one fixing of the link. In boring the crank webs of built up cranks in such a
machine, the rough holes are trepanned out by one pair of headstocks operating
from one face of the web and the other pair from the opposite face, each boring
through half the thickness, the finished boring being effected by boring bars
operated by one pair of headstocks, such boring bars being secured in the trepanning
tools of such headstocks or otherwise as may be preferred, the trepanning tools of
the other pair of headstocks remaining stationary and doing duty if required as
bearings to support the ends of the boring bars while fine boring.
Figures 8 and 9 show in transverse vertical section and plan respectively how
two headstocks may be arranged side by side so as to operate upon the two studs
at one side of a middle link at the same time, or to bore the two holes in an outside
link or in a crank web at the same time and it will be obvious that by placing two
such pairs of headstocks opposite to one another, as the headstocks in Figure 5 for

page_text: example, all four studs of a middle link can be turned, faced and bored at the same
time, or both holes in an outside link or in a crank web, rough bored at the same
time by one pair of headstocks and then fined bored at the same time by the other
pair of headstocks. Or two opposite headstocks may be used to rough turn the two
opposite studs of a middle link of a pitch chain, or to rough bore one hole of an
outside link or of a crank web, the other two opposite headstocks being used to fine
turn the roughed out studs or to fine bore the roughed out holes, the chuck con-
taining the link or the crank web being shifted to bring the studs or the holes as
the case may be opposite the appropriate spindles.
A is a headstock fixed permanently on a suitable bed B, and A¹ is a similar
headstock adapted to be adjusted laterally on the part B of the bed so that its
spindle may be placed at any required distance from the spindle of the headstock A
to correspond with the pitch of the studs to be turned or the holes to be bored.
The hollow mandrils C and the spindles H are arranged as in the machine illustrated
in Figure 5 but as it is sometimes necessary to place the spindles closer together
than ordinary back geared headstocks would allow of, I, in such cases, arrange the
headstocks with worm wheels G' for rotating the mandrils and spindles instead of
with the ordinary speed ccnes and spur gearing. These worm wheels are driven
by worms mounted on the shafts G2 which may be driven by separate driving
pulleys or be geared together and driven by one pulley G³ as shown. Clutches G
are interposed between the gearing and the shafts G2 carrying the worms in order
to admit of the said shafts being thrown out of gear by hand by means of the clutch
levers G³ for example or by any suitable automatic devices. Hand gear for
traversing the spindle H is shown in connexion with one of these headstocks, but
it is obvious that self acting feed gear, such as that shown in Figures 5, 6 and 7ª
for example, may be applied to either or both of the headstocks.
Figure 9 shows how, with headstocks arranged as in Figure 9, the waists or
reduced parts of crank webs can be cut out with trepanning tools mounted in such
headstocks. A A A are three crank webs placed together side by side, and B B
are two trepanning tools mounted in two headstocks placed side by side as in
Figure 9 so as to operate upon the material that is to be removed from the waists
or reduced parts of the crank webs, it being understood that two other trepanning
tools carried by two other headstocks may be operating upon the same material at
the same time from the other faces of the webs.
Several of the outside links prepared as above described are next placed on a
mandril fixed in the central hole of the circular table of a slotting machine and
finished round the curved ends by means of the ordinary slotting tool, or preferably
by means of a tool mounted in a special tool-box in which the tool is freed more or
less from rubbing against the material on the return or up stroke. This tool box is
illustrated in Figures 10, 11 and 12 of the drawings in which Figure 10 is a front
elevation, Figure 11 a side view and Figure 12 an underside view with the part C
removed. The tool A is held by two set screws B B in a holder C carried by a
hinge-pin D which passes through the holder and through two jaws E E which are
placed at an angle to the base For to the direction in which the tool makes its
return stroke; this angular position of the jaws constitutes the essential difference
between my improved tool-box and ordinary tool-boxes of this type. This angular
position of the jaws causes the tool to have a greater clearance during its return
stroke than is given by an ordinary tool box, both longitudinally and transversely.
The tool-box is bolted to the bottom end of the slotting machine rani G, the central
fixing bolt H being also used as a pivot round which the tool box can be moved to
whichever side is necessary to suit the direction in which the tool A is to cut and
to obtain the full advantage of clearance from the angular jaws. A spring brings
the cutting end of the tool A into the proper position each time the return or non-
cutting stroke of the machine is performed. In some cases a balance weight hooked
on to the rear end of the tool suffices for this purpose.
This construction is also applicable to the tool boxes of shaping, planing and
other such like machines.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
First Constructing the links of pitch chains and other similar articles by planing
bars of material to suitable sections, cutting the said bars to lengths, and then
turning, facing, boring and shaping as herein before described.
Second-The grooving or splitting-off tool consisting of a tool-bar with one or
more separate cutters inserted therein and connected therewith by a hinged joint
substantially as hereinbefore described, and illustrated in Figures 1, 2, 3 and 4 of
the drawings.
Third In grooving or splitting-off tools of the kind forming the subject of the
second claiming clause hereof, arranging the cutters so that a diamond pointed or
other similar cutter cuts a nick or groove in the material to be cut before the square
nosed cutter acts as hereinbefore described, and illustrated in Figures 1, 2, and 3 of
the drawings and for the purpose specified.
Fourth The improved machine for turning, facing, and boring the links of pitch
chains and other similar articles, arranged combined and operating substantially as
hereinbefore described, and illustrated in Figures 5, 6, 7 and 74 of the drawings.
Fifth The improved machine for turning, facing and boring the links of pitch
chains and other similar articles, arranged, combined and operating, substantially
as hereinbefore described, and illustrated in Figures 8 and 9 of the drawings.
Sixth The improvement in tool boxes which consists in forming the jaws,
between which the tool-holder is hinged, at an angle to the direction in which the
tool makes its return stroke substantially as hereinbefore described, and illustrated
in Figures 10, 11 and 12 of the drawings and for the purpose specified.
Dated this 25th day of January 1892.
J. A. SNOWDON,
Per W. H. Beck,
115, Cannon Street, London, Agent.