Improvements in the Manufacture of Weldless Link Chains from Cruciform Bars.
Year: 1898

page_text: Date of Application, 19th Dec., 1898-Accepted, 22nd Apr., 1899
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Weldless Link Chains from
Cruciform Bars.
I, OTTO KLATTE, of Düsseldorf, Gothestrasse 36, Director of Works, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement: -
This invention relates to the manufacture of weldless link chains from cruci-
form bars.
It has been found that in rolling or pressing a solid metal bar of cruciform cross
section to form a weldless link chain, (which is effected in a four roll rolling mill
or in a four die stamping press, the rolls or dies of which are situated in pairs
opposite to each other and all converge towards one place where they are formed
with apertures and recesses for the passage and the reception of the metal of the
cruciform bar), the metal of the bar has never been properly displaced and dis-
tributed. This improper displacement has generally caused the occurrence of
scams in the ends of the links of the finished chain, said seams extending laterally
from the inside towards the outside of the ends of the links and sometimes when
they were not closed up by welding appearing outwardly in the form of scars.
These seams (which it has been found by experience considerably diminish the
strength of the rolled or pressed chains) are produced in consequence of the
metal (which is displaced out of two oppositely situated limbs of the cruciform
bar in order to form the inner opening of each chain link) becoming forced up
and turned down in the form of laps; the metal becoming pressed with its colder
outer side against and into the two other limbs which are situated at right angles
to the first two limbs.
The cause of the formation of these seams has been due partially to the cross
sectional shape of the cruciform bar hitherto employed and partly to the corre-
sponding cross sectional form of the operating surfaces of the rolls or pressing
dies. Hitherto a cruciform section has always been employed, the limbs of
which were rounded off in a convex manner at their outer ends and met together
at acute angles at their inner ends whilst the periphery of each of the four
co-operating rolls or of the four co-operating pressing dies was made of pointed
form to correspond with the said acute angles.
Now the present invention has for its object to prevent the formation of seams,
which diminish the strength of the rolled or pressed chains, with the further
advantage of greatly reducing the wear and tear of the rollers or dies. The
new method consists in forcing the material (which must be displaced out of the
two oppositely situated limbs of the cruciform bar for the purpose of forming
the inner opening of the chain links) in such a manner into the two other adjacent
limbs that the material which has been displaced out of the first mentioned limbs,
s caused to drive in front of it an amount of material corresponding to the
extent of its movement out of the adjacent limbs (that is to say, by gradual dis-
placement around a curve connecting two adjacent limbs of the cruciform bar,
as hereinafter described) into the recesses of the rolls or dies designed for the
°

page_text: last mentioned limbs in an are shaped path from the ends of the recesses towards
the centre of the link recesses. The arrangement is such that further movement
of this material in the recesses produces a meeting and a setting up of the material
and consequently a complete filling of the recesses; (it being understood that the
cross of the bar to be rolled or pressed is of suitably less dimensions than the
capacity of the chain link cross formed by the four rolls or press dies). In this
operation a portion of the superfluous displaced mass is driven further in the
exit direction through a square or other shaped link connection or core and with
the material which was cut out laterally between two recesses, is pressed and pushed
into the overflow recesses provided for the material at these places.
For this purpose the cruciform metal bar (which is to be rolled or pressed into a
weldless link chain) is made in cross section of a form which is characterised by
are shaped curved or rectilinear obtuse angled connecting surfaces at the places
where the limbs join one another with the object of preventing the formation of
seams, and the limbs are recessed or concavely curved at their outer ends with
the object of preventing the formation of an outer fin. Further the hitherto
pointed operating parts of the rolls or pressing dies are now truncated so as to
correspond with the curved or obtuse angled connecting surfaces between the limbs
of the bar, the plane of truncation being parallel to the axis of the rolls or
pressing segments or at right angles to the direction of pressure in pressing dies
which are movable in one direction only.
For the purpose of showing clearly the difference between the new means and
the means hitherto employed, reference is made to the accompanying drawings
which illustrate in Figures 1 to 10 the hitherto employed means and in
Figures 11 to 19 the new means in the different stages of the formation of a
chain.
I shall first describe the means hitherto employed.
Figure 1 is a vertical section through the meeting parts of a set of 4 rollers
or pressing dies of the kind hitherto employed acting upon a cruciform bar of the
old type.
Figure 2 is an elevation of the periphery of one of the 4 rollers or of the pressing
surface of a pressing die and
Figure 3 is a section on the irregular line A B C D of Figure 2.
Figure 1 shows the 4 rolls or pressing dies acting upon the cruciform bar
which is received into the milled-out recesses of said rolls or dies; the teeth
(gh Figures 2 and 3) of the rolls or pressing dies entering the flanks or sides of
the limbs of the bar and forcing the material away from one limb and towards the
adjacent limb. The beginning and the end of the penetration of the rolls or dies
into the flanks are indicated by full lines, while some intermediate stages of this
penetration are indicated by dotted lines.
Figure 4 illustrates in side elevation the form which the cruciformi bar assumes
during the rolling or pressing operation.
Figures 5 to 10 are cross sections through Figure 4 on the lines m n, o p, qr, s t,
u, w 2.
Figure 5 shows the old form of cruciform bar before the commencement of the
rolling or pressing operation; y indicates the acute angle between two adjacent
limbs, and z indicates the convexly rounded form of the outer ends of the limbs.
Figure 6 is a cross section of the said bar after the teeth of the rolls or pressing
dies have entered two oppositely situated limbs and have forced the material out
of the flanks of the limbs to the places a a a a. By the further penetration of
the teeth of the rollers or pressing dies more material is displaced from the
flanks of the limbs towards the adjacent limbs (Figure 7). In consequence of the
sharpness of the acute angle y, Figure 5, this displaced metal has no tendency to
flow around said angle and since the recessed pressing surfaces of the rolls or
dies still afford room for turning the metal over because they do not yet bear
upon the oppositely situated material in the said angle, the said displaced material
is thereby forced up and so turned over as to produce the laps or over-

page_text: lappings bbb b. When the teeth of the rollers or dies have come as near to
each other as is possible, that is to say when they have reached their final depth
of penetration, the laps bare pressed into the adjacent limbs as shown in Figure 8,
thus forming the seams c c c c which according to the heating to which the bar
has been subjected are frequently but not always apparent in the form of external
scars.
Figure 4 shows the formation of laps at a, b and c. In this figure, e indicates
the outer fins, and f the inner fins which remain between the links. At the
places where the teeth y of the rolls or pressing dies (Figure 2) act, the inner
fins meet together in cross shape as shown in Figure 9; whilst at the place
of operation of the roll or die teeth h, (Figure 2) the outer fins e and the inner
fins meet together and also form a cross (see Figure 10).
19.
I will now proceed to describe the new means with reference to Figures 11 to
Figures 11, 12 and 13 are similar views to Figures 1, 2 and 3, but with the
difference that the teeth g h of the rolls or dies (which are pointed in Figures 2
and 3) are here in Figures 12 and 13 made with their operating faces blunt
parallel to the axes of the rolls or die segments, or at right angles to the direction
of pressure in the case of press dies movable only in the lengthwise direction.
Figure 11 illustrates various stages of the operation of the rolls or die teeth
upon the flanks of the cruciform bar.
Figure 14 is a side elevation showing the form which the cruciform bar acquires
during the rolling or pressing process.
Figures 15 to 19 are cross sections through Figure. 14 on the lines m n, op,
gr, st, and u . Figure 15 shows the new shape of cruciform bar before the
commencement of the pressing or rolling process. ¹ indicates the curved surface
connecting two adjacent limbs, and indicates the concavity or recess in the
outer end of each of the limbs. In Figure 16 the teeth of the rolls or dies have
entered two oppositely situated limbs and have displaced material out of the
flanks of the limbs to a a a a. This material is enabled, in consequence of the
curved connecting surface y¹ between two adjacent limbs, to drive the metal of
the adjacent limb situated in front of it around the said curve y' forwards into the
mass of the said adjacent limb in the direction of the link end which is about to be
formed in this limb, that is to say, there is no formation of laps. The form of the
recess or concavity in the outer end of each limb is so chosen that that part of it
which enters the recesses of the roll or die that are to form the links is filled up
by the metal which has been displaced in the manner above stated, thereby
of fins on the outside of the links.
also preventing the formation
There is therefore no formation of laps but only such a gradual flow or displace-
ment of the metal that after the teeth of the rolls or dies have penetrated into the
cruciform bar to their utmost extent, the cross-sectional form of the cruciform bar
on the liner of Figure 14 will be that shown in Figure 17 without seam and
the cross sectional forms of the bar on the lines stand uv of Figure 14 will be
as shown in Figures 18 and 19 respectively. From Figures 18 and 19 and from
Figure 14 it will be seen that between the links in addition to the fins e and f
there still remain the rectangular cores d and i which result from the curved
connecting surface between adjacent limbs of the bar which as already stated
may also be rectilinear and from the obtuse angled parts of the rolls or pressing
dies. These connecting cores allow of the displacement of superfluous material
in the longitudinal direction of the chain bar from one link to the adjacent link,
whereas the formation of the two cold crossing places of the fins shown in
Figures 9 and 10 does not allow the said displacement of material. In the
latter case the superfluous material must escape sideways out of the recesses and
thus form a fin.
The further treatment of the chain bar thus produced in order to form a
chain consists in punching away the fins, shearing away the connecting portions
and removing the material which has remained at the sheared places.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. The process of manufacturing weldless link chains from cruciform bars
which process consists in forming a bar of cruciform section with curved or
rectilinear parts connecting the limbs and with recessed outer edges and in then
rolling or pressing said bar so as to cause the displaced metal from one link to
How into the next link without any seam, substantially as described.
2. In the manufacture of weldless chain links from cruciform bars, the employ-
ment of cruciform bars of the cross section shown in Figure 15 as and for the
purposes described.
3. In the manufacture of weldless chain links from cruciform bars the use of
four co-operating rolls or pressing dies having their operating portions rounded or
flattened as and for the purposes specified."
Dated this 19th day of December 1898.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London Chartered Patent Agents.