At the Royal Naval Exhibition, London, Messrs. William Reid & Co. are
exhibiting their weldless steel chains, which we now illustrate.
Of the many advantages claimed for steel chains, it may be prominently
noted that a very important saving of weight is effected on account of
their possessing such a high breaking strain, compared with the
ordinary welded iron chains. To illustrate this, it may be stated that
a given length of the weldless steel chain is 35 to 40 per cent. less
in weight than an equivalent length of iron chain, will stand the same
breaking strain as the latter, and indeed, where steel of special
quality is used in making the weldless chains, this difference can be
increased as much as 70 to 80 per cent. Whereas superior iron chains
break at a strain at 17 tons per square inch, these weldless steel
chains will stand a strain of 28 to 30 tons, with 20 to 26 per cent.
elongation.
[Illustration: Figures 1. Through 9., 1_a_, 1_b_ and 3_a_
MANUFACTURE OF WELDLESS CHAINS.]
Again, there is greater security in their use from the fact that there
are no welds, and they give warning of the limit of strain to which
they can bear being approached, by elongation, which can be carried to
a considerable extent before the chain breaks. Moreover, over, in
chains made by this process, the links are all exactly alike. Though
the life of a weldless steel chain is said to be twice that of an
ordinary one, the price per length is little more than that of best
iron chains.
They are made in lengths of from 40 to 50 feet, being compressed from
a solid rolled steel bar, the section of which is shaped like a
four-pointed star. In the first place holes are pierced at intervals
down the length of the bar, thus determining the length of the several
links. Then the bar is notched between the holes so as to give the
external form of the links. The next step is "flattening out," which
presses the links into shape on their inner side, but leaves the
openings still closed by a plate of metal. They are then stamped out
so as to round them up, and the metal inside them is punched out, and
the edges "cleaned," or trimmed off. The links are now parted from one
another and stamped again, to insure equal thickness in all parts of
the chain. The only processes now to be gone through are dressing and
finishing. According to the die used, the shape of the links can be
varied to suit any required pattern. The lengths of chain thus made
are joined by spiral rings made of soft steel, the convolutions being
afterward hammered together till they become solid. A ring of this
description, ¾ inch diameter, underwent a strain of 46,200 lb., that
is, 23 tons to the square inch, its elongation being 21 per cent.
These chains have passed satisfactorily the tests of the Bureau
Veritas, and both that association and Lloyd's have accepted their use
on the same conditions and under the same tests as ordinary chains.
So much for the general idea of punching steel chains. We will now
describe a recent invention by which superior steel chains are
produced, the author of which is Mr. Hippolyte Rongier, of Birmingham,
Eng. He says:
My invention has for its object the manufacture of weldless stayed
chains, whereof each link, together with its cross strut or stay, is
made of one piece of metal without any weld or joint; and the
invention consists in producing a chain of stayed links from a bar of
cruciform section by the consecutive series of punching, twisting and
stamping operations hereinafter described, the punching operations
being entirely performed on the metal when in the cold state.
Figs. 1 to 10 show the progressive stages in the manufacture of the
chain, and the remaining figures show the series of tools that are
employed.
The general method of operation of making stayed chains according to
my invention is so far similar to the methods heretofore proposed for
making unstayed chains from the bar of cruciform section that the
links are formed alternately out of the one and the other pair of
diametrically opposite webs of the rod, the links, when severed and
completed, being already enchained together at the time of their
formation. The successive operations differ, however, in many
important practical respects from those heretofore proposed, as will
appear from the following detailed description of the successive steps
in the process illustrated by Figs. 1 to 10.
I will distinguish the one pair of diametrically opposite webs of the
bar and the notches and mortises punched therein and the links formed
therefrom from the other pair by an index figure 1 affixed to the
reference letters appertaining thereto.
_a a_ are one pair of diametrically opposite webs, and _a' a'_ the
other pair of webs of the bar.
[Illustration: Figures 2_a-_b, 6_a_, 4_a-b_, 7 _a-b_ and 10 _a-b_
MANUFACTURE OF WELDLESS CHAINS]
The first operation illustrated in Fig. 1 is to punch out of the edge
of one of the webs, _a_, a series of shallow notches, _b_, at equal
intervals apart, corresponding to the pitch of the links to be formed
out of that pair of webs and situated where the spaces will ultimately
be formed between the ends of that series of links. The notches are
made with beveled ends, and are no deeper than is absolutely necessary
(for the purpose of a guide stop in the subsequent operations, as
hereinafter described), so as to avoid, as far as possible, weakening
the bar transversely. This operation is repeated upon one of the pairs
of webs _a'_; but whereas in the first operation of notching the web
the "pitch" of the notches is determined by the feed mechanism, in
this second operation of notching the notches, _b_, cut in the web,
_a_, serve as guides to influence and compensate for any inaccuracy of
the feed mechanism, so that the second set of notches, _b'_, shall be
intermediate of and rigorously equidistant from the first set of
notches, _b_. This compensation is effected by the notches, _b_,
fitting on to a beveled stop on the bed of the punching tool by which
the notches, _b'_, are cut, the beveled ends of the notches, _b_,
causing the bar under the pressure of the punch to adjust itself in
the longitudinal direction (if necessary) sufficiently to rectify any
inaccuracy of feed. These notches, _b b'_, similarly serve as guides
to insure uniformity of spacing in the subsequent operations of
punching out the links.
The second operation (illustrated in Fig. 2) is to punch out of the
pair of opposite webs, _a a_, pairs of oblong mortises--two pairs, _c
c_, and one pair, _d d_. These three pairs of mortises (which might be
punched at separate operations, but are preferably punched at one
stroke of the press) are situated as close as possible up to the faces
of the other pairs of webs, _a' a'_, the pairs of mortises, _c c_,
being so spaced as to correspond in position to the eyes of the links
to be formed, to which they correspond approximately in form, while
the pair, _d_, correspond in position to the notches, _b_, and
therefore to the intervals by which the links formed out of the same
pair of webs, _a a_, will be separated when completed. This operation
is continued along the whole length of the pair of webs, _a_. It will
be observed that a considerable thickness of metal is left at _a*_
between the notches, _b_, and the mortises, _d_. This is of primary
importance and is one of the essential features of my method of
manufacture, inasmuch as by first punching out the mortises, _d_, the
subsequent removal of the metal from between the outer ends of the
links is greatly facilitated, while by leaving the solid metal, _a*_,
the transverse strength of the webs, _a a_, is not materially
diminished, so that when the operation of punching the mortises, _c_
and _d_, in the other pair of webs, _a'_, is performed the bar will
not be bent and crippled, as would inevitably be the case were the
whole of the metal opposite the notches, _b_, which is ultimately to
be removed, to be punched out at so early a stage of the manufacture.
The operation of punching the pairs of mortises, _c'_ and _d_, having
been repeated along the other pair of webs, _a'_, it will be observed
that like the notches, _b_, the mortises, _c d_, in the one pair of
webs alternate with those, _c' d'_, in the other pair of webs.
The third operation (illustrated in Fig. 3) is to elongate the
mortises, _c d_, and bring the mortises, _c c'_, more nearly to the
final form. This is performed by punches similar to but larger (in the
direction of the length of the rod) than those used in the second
operation.
The third operation, which is repeated upon both pairs of webs, _a a
a' a'_, may be considered as a second stage of the second operation,
it being preferable to punch out the mortises in two stages in order
to remove sufficient metal without unduly straining the bar.
The fourth operation (illustrated in Fig. 4) consists in roughly
shaping the ends of the links externally by punching out the portions,
_a*_, of the webs, _a_, between the links lying in the same plane or
formed out of the same pair of webs. This operation is repeated on the
other pair of webs, _a'_. Up to this point a continuous core of metal
has been left at the intersection of the two pairs of webs.
The fifth operation (illustrated in Fig. 5) consists in punching out
the portions, _e_, of the core at each side of the cross stay of the
link, so as to separate the cross stay from the outer ends of the
adjacent links. This operation is performed by removing a portion only
of the metal of the core which intervenes between the cross stay and
the outer ends of the adjacent links enchained with the link under
operation--that is to say, portions, _e*_, of the core are temporarily
left attached to the outer ends of the links in order to avoid
crippling or bending the bar, which might occur were the whole of this
metal, which is ultimately to be removed, to be punched out at once,
these portions, _e*_, being supported by the bed die in the operation
of punching out the spaces, _e_, as hereinafter described. This
operation having been repeated upon both pairs of webs, it will be
observed that the rod-like form of the chain is now only maintained by
the portion of the core at the points, _f_, where the inner side of
the eye or bow of one link is united with that of the next one. The
severing of these intervening portions of the core and the breaking up
of the rod into the constituent links of the chain constitute the
sixth operation.
The sixth operation (illustrated in Fig. 6) is performed by torsion,
and for this purpose one end of the rod is held fixed while the other
is twisted once or twice in opposite directions, until by fatigue of
the metal at the points, _f_, the whole of the links are severed
almost at the same instant, and a chain of roughly formed stayed links
is produced.
The seventh operation (illustrated in Fig. 7) is to remove the
superfluous projecting pieces of metal both from the inside and
outside of the ends of the links. For this purpose the two ends of
each link are operated on at the same time by two pairs of punches
corresponding to the outline of the ends of the link.
The eighth operation (illustrated in Fig. 8) is to bring the ends of
the links to their finished rounded form. This is performed by
stamping both ends of each link at the same time between pairs of
shaping dies or swages.
The ninth operation (illustrated in Fig. 9) is to bring the middle
portion of each link--that is to say, the side members and the cross
stay--to the finished rounded form, which is also performed by means
of a pair of dies or swages.
The tenth and last operation (illustrated in Fig. 10) is to contract
the link slightly in the lateral direction in order to correct any
imperfections at the sides left by the two previous operations and
bring the link to a more perfect and stronger form, as shown. This
operation has the important result of strengthening the link
considerably by contracting or rendering more pointed the arched form
of the bow or end of the link, and also by thickening the metal at
that part where the wear is greatest, this thickening of the metal at
the ends of the link occurring in the direction of the line of strain
(as indicated by _x_ in Fig. 10) and being brought about by the
compression or "upsetting" of the metal at the end of the link. It may
be preferable to perform this operation immediately after the seventh
operation, and I reserve the right to do so.
In the case of large cables only the metal is preferably heated for
the eighth, ninth, and tenth operations.
I will now refer to the figures which illustrate the series of tools
whereby the above mentioned operations are performed.
Fig. 1_a_ shows a plan (the punch being in section) and Fig. 1_b_ an
elevation of the bed die of the tool by which the notches _b_ of the
first operation are performed. The feed mechanism is not shown, but
might be of any ordinary intermittent kind. _g_ is a groove in the
bed, in which lies the lower vertical web of the rod, of cruciform
section, the two horizontal webs lying upon the bed with the edge of
the web to be notched lying just over the die, in which works the
punch, B, of which B' is the cutting edge. The punch is operated in
the usual way, its lower end, which does not rise out of the die,
acting as a guide. B* is the beveled stop in the groove, _g_, which by
fitting in the notches, _b_ or _b'_, corrects inaccuracies of the
feed.
Fig. 2_a_ is a sectional plan and Fig. 2_b_ an elevation of the tool
by which the second operation is performed, the same tool being also
used for performing the third operation. (Illustrated in Fig. 3_a_.)
_h h_ are a pair of bed-dies having a space _h'_ between them to
receive the lower web of the bar, and having notches, C C and D D, in
their inner ends, forming counterparts of the punches by which the
pairs of mortises, _c d_, Fig. 2, are punched in the pair of webs
lying upon the bed-dies, _h_. These bed-dies are fitted to slide a
little in opposite directions upon a suitable bed plate and are caused
by the inclined cams, _i'_, on the guides, _i_, of the press head
(which pass through corresponding apertures in the bed-dies, _h_) to
approach each other at the moment the punches come down on the work,
so as to grip the lower web of the rod and support the pair of webs
being operated on close up to the sides of the lower web lying in the
space _h'_, while when the punches rise the bed-dies move apart, so
that the web is quite free in said space _h'_ and the rod may be
easily fed forward for a fresh stroke of the press. B* is the beveled
stop in the space, _k'_, as in the tool first described. The bed-dies
_h_ have a second set of notches C' D' at their outer ends, similar to
but longer than those C D, so that by reversing the bed-dies they will
form counterparts for a second set of punches corresponding thereto
for performing the third operation--_i.e._, enlarging the mortises, _c
d_, as represented in Figs. 3 and 3_a_; or, instead of adapting the
dies, _h_, to perform the two operations, separate tools may be used
for the second and third operations.
Fig. 4_a_ is an elevation and Fig. 4_b_ a sectional plan of the tool
for performing the fourth operation--namely, removing the portion
_a*_, Figs. 3, 3_a_, 4_a_, and 4_b_. This is done by a pair of
punches, A*, corresponding in shape to the ends of the link in the
rough and to the aperture shown in the bed-die, _k_, Fig. 4_b_, which
has a groove, _k'_, to admit the lower web of and to guide the rod.
The beveled stop, B*, used in operating on the pair of webs, a,
corresponds to the notches, _b'_; but in operating on the webs, _a'_,
the stop must be replaced by one corresponding to the aperture left by
the removal of the portion, _a*_.
Fig. 5_a_ is an elevation, Fig. 5_b_ a plan, and Fig. 5_c_ a
longitudinal vertical section of the tool for performing the fifth
operation, the work being shown in section in the latter figure. It
consists of a bed-die, _l_, with groove, _m_, to receive the lower
web, but terminating at a distance from the die apertures, so as to
leave supports, _n_, for the parts, _e*_, of the rod to resist the
downward pressure of the punches, E, which remove the portions, _e_,
from each side of the cross stay, as shown in Figs. 5_b_ and 5_c_. The
correct position of the work in regard to the punches is insured by
these supporting parts, _n_, which terminate the grooves, _m_.
Fig. 6_a_ is an elevation of the winch for performing the sixth
operation.
Fig. 7_a_ is an elevation and Fig. 7_b_ a plan of the tool for
performing the seventh operation. P P are the punches for trimming the
outside and Q Q those for trimming the inside of the ends of the
links. The links adjacent to the one to be operated on are brought
together into the position shown in dotted lines, the bed-die having
an aperture in it to admit of this, so that both ends of the link to
be trimmed may be operated on together.
The tool for performing the eighth operation consists of a pair of
swages, the bottom one only being shown in Fig. 8_a_. The swages
correspond to the intended rounded sectional form of the ends of the
link, which is placed in position between the swages in a similar
manner to that described for Fig. 7_b_, so that both ends are rounded
or finished off at once.
Fig. 9_a_ is a plan of the bottom swage of the tool for performing the
ninth operation, the upper swage corresponding thereto at least in so
far as the middle part of the link to be operated on is concerned.
The tool for performing the tenth operation is represented in
elevation and plan in Figs. 10_a_ and 10_b_. It consists of a pair of
bed-dies, R, fitted to slide together and operated by the cams, s, on
the guide rods, S, the operation being similar to that of the tool
shown in Figs. 2_a_ and 2_b_, except that there are no punches, and
that the link which lies in the cavity of the dies is merely
compressed in the lateral direction by the inward motion of the
bed-dies.
My invention further comprises a modification of the above described
process, which has for its object to enable the weldless stayed links
to be made as short and particularly as narrow as may be necessary in
order to adapt the chain to run over the sheaves of pulley blocks and
to suit other purposes for which short-link welded chain has
heretofore only been available.
[Illustration: Figures 5_a-c_, 8_a_, 9_a_, 10-12
MANUFACTURE OF WELDLESS CHAINS.]
In the manufacture of chains by the aforesaid process of punching
there is a practical minimum limit for the dimensions of the punches
which cannot be reduced without compromising their efficiency, and
consequently the width (and therefore the length) of the link must
necessarily bear a certain proportion to the thickness of the web of
metal out of which it is formed, since the breadth of the link depends
on the length of the cross stay, which is determined by the breadth of
the mortises forming the eyes of the link. The present modification
enables these dimensions to be reduced without reducing the
dimensions, and consequently the efficiency, of the punches which form
the eyes of the link. The modification applies to what I have
designated the fifth operation of the above described process; and it
consists in punching out the middle of the cross stay (so as to leave
only two short stumps jutting inward from the side members of the
link), this operation serving to interrupt the continuity of the core,
which was the object of the fifth operation. For this purpose I
substitute for the pair of punches illustrated in Figs. 5_a_ and 5_c_
a single punch, which removes that part of the "core" of the cruciform
bar which is situated at the middle of the strut. This tool is
represented in Fig. 11, and the effect of its operation is shown in
Fig. 12. The subsequent operations, herein designated the sixth,
seventh, eighth, and ninth operations, are performed as hereinbefore
described; but the tenth operation has the effect of closing together
the two stumps, _g g_, until they abut together at the middle of the
link and together constitute a cross strut or stay, which prevents any
further lateral collapse of the link. In the operation of closing up
the gap between the stumps, _g g_, the link is brought to the narrow
form shown in Fig. 12, the eyes of the links being only just wide
enough to receive the end of the adjacent link enchained therewith
without gripping it. This operation is performed by a tool similar to
that shown in Figs. 10_a_ and 10_b_, above referred to.
* * * * *