In a tufting needle for tufting machines comprising an operative shank portion of oblong cross-section and containing a thread guide and eye and an anchoring shank portion by which the needle is embedded in a needle module, said anchoring portion is of elliptical or rhombic cross-section and the major axes of the cross-sections of both portions are disposed in substantially the same plane.

DESCRIPTION OF THE PRIOR ART 
The invention relates to a tufting needle for needle modules of tufting 
machines, wherein the free shank portion has a flat cross-section and is 
provided with a thread groove and an eye. 
For the production of needle modules of tufting machines, tufting needles 
of the aforementioned kind are employed in which the shank portion, also 
termed stock, to be moulded in the module body is of circular 
cross-section. Tufting needles of this construction meet requirements when 
used for modules having a comparatively wide needle distribution in which 
the needles are arranged at correspondingly large spacings in the module 
body. However, tufting needles of such construction present difficulties 
for making needle modules with a dense needle distribution because the 
needle pitch is limited by the diameter of the shank portion to be 
embedded and because moulding them into the module body leaves much to be 
desired if the spaces between the shank portions to be embedded are very 
small. 
To remedy this, a tufting needle for making needle modules for tufting 
machines has already been proposed (DE-OS 28 28 246) wherein not only the 
free shank portion but also the portion to be embedded or the anchoring 
shank portion has a flat cross-section. By reason of the flat construction 
of the portion to be embedded, it is possible to arrange tufting needles 
of this kind at close spacings on the needle module. Apart from this, the 
flat construction of the shank portion of the known tufting needle to be 
embedded gives security against rotation thereof in the needle module. 
However, the flat construction of the shank portion of the known tufting 
needle that is to be embedded is not an optimum for moulding it into the 
module body and for anchoring it therein. 
DESCRIPTION OF THE INVENTION 
The invention aims to provide a tufting needle for needle modules of 
tufting machines, which has the advantages of the known needle with a flat 
shank portion to be embedded but in addition is particularly suitable for 
moulding into the module body and for being securely anchored therein. 
The tufting needle according to the present invention is characterised 
particularly in that the shank portion thereof to be embedded is of 
elliptical or rhombic cross-section, with the major axes of the 
cross-sections of the free shank portion and of the portion to be embedded 
being disposed in the same or nearly the same plane. 
By reason of the construction of the new tufting needle in accordance with 
the invention, it is likewise possible to arrange it in the needle module 
at a close pitch, especially if, as is preferred, the cross-section of the 
shank portion to be embedded is considerably larger along its major than 
its minor axis. In addition, because of its construction, the new tufting 
needle is particularly suitable for moulding into the module body because, 
during the moulding in operation when the shank portion to be embedded has 
an alloying material cast about it, the alloying material can flow without 
hindrance from the narrow longitudinal edges of the shank portion to be 
embedded between the adjacent side faces thereof. Further, the 
construction of the new needle facilitates secure anchorage in the module 
body because, after being moulded therein, the embedded portion is 
intimately surrounded by the material of the module body without any 
defective locations. 
The cross-sectional shape of the shank portion to be embedded likewise 
secures the new tufting needle in the module body against rotation. As a 
safeguard against axial displacement of the new needle in the module body, 
the invention provides for the shank portion to be embedded to have a flat 
in known manner at a spacing from its front and rear ends at least at one 
side. When moulding the needle into the module body, this flat is filled 
with alloying material which then prevents longitudinal displacement of 
the needle in the module body. 
After installing needle modules made with the new needles in a tufting 
machine, to ensure that the new needle will assume the correct position in 
relation to the associated gripper of the machine, it can be moulded into 
the module body with an appropriate twist of a few degrees about its 
longitudinal axis. On the other hand, the invention can provide for the 
free shank portion of the new needle to be twisted a few degrees in known 
manner relatively to the shank portion to be embedded.

The tufting needle shown in FIGS. 1 to 5 has a free shank portion 11 and a 
shank portion 12 that is to be embedded. 
The free shank portion 11 has a flat rectangular cross-section. The point 
of the needle is formed at 13 by the front end of the free shank portion. 
Adjoining the needle point, the free shank portion is provided with the 
eye 14. This is followed at one side face of the free shank portion by a 
thread guide channel 15 which extends substantially up to the junction 16 
between the free shank portion and the portion to be embedded. At its 
opposite side face, the free shank portion is provided adjacent to the eye 
14 with a hollow fillet 17 and a chamfer 18 for the passage of a gripper 
co-operating with the needle. 
The shank portion 12 to be embedded has an elliptical cross-section. Its 
major axis is considerably longer than its minor axis, namely in the ratio 
of about 2:1. At a spacing from its front and rear ends, the shank portion 
to be embedded is provided at both opposed side faces with a respective 
flat 19. 
As shown in FIGS. 2 and 3, in the illustrated tufting needle the free shank 
portion 11 is twisted by an angle .alpha. to the shank portion to be 
embedded, namely by appropriately twisting the needle at the junction 16 
between the two shank portions. The twist amounts to about 6.degree.. 
The tufting needle of which the shank portion 20 to be embedded is shown in 
cross-section in FIG. 6 has a construction as shown in FIGS. 1 to 5 except 
that the cross-section of the shank portion to be embedded is rhombic 
instead of elliptical. Again, this cross-section is considerably longer 
along the major than the minor axis, the proportion of dimensions again 
being about 2:1. 
The needle module shown in FIG. 7 is made from tufting needles of the FIGS. 
1 to 5 construction. In this module, the shank portion 12 of the tufting 
needles is so embedded in the module body 21 that the major axis is 
accurately parallel to the end faces 22 of the module body. The small 
arrows shown in the module body 21 indicate how the alloy material of 
which the module body is formed and by which the needles are moulded in 
tends to flow between the side faces of the shank portion 12 from the 
narrow longitudinal edges thereof. 
The needle module of FIG. 8 is made from tufting needles having the FIG. 6 
cross-section of the shank portion 20 to be embedded. In other respects, 
this module corresponds to that in FIG. 7. 
The needle module of FIG. 9 is made with needles of which the shank portion 
23 to be embedded is likewise elliptical in cross-section but without any 
twist between the two shank portions. Since there is no such twist, their 
shank portion to be embedded is so moulded into the module body 21 that 
their major axis is in each case at an angle .beta. to a line parallel to 
the end faces 22 of the module body 21. The angle .beta. is about 
6.degree.. 
The needle module of FIG. 10 corresponds to that of FIG. 9 except that it 
is made with tufting needles of rhombic cross-section at their shank 
portions 24 to be embedded. 
The small arrows included in FIGS. 8 to 10 are likewise intended to 
indicate how, during moulding of the needles into the module body, the 
allow material from which the latter is formed flows between the 
longitudinal faces of the shank portions to be embedded from the narrow 
longitudinal edges thereof. 
In so far as the shank portions to be embedded are of rhombic 
cross-section, the latter is, as shown in FIGS. 6, 8 and 10, rounded off 
at the narrow longitudinal edges as well as the central part of its side 
faces, which likewise contributes to good moulding-in in the module body.