Shackle toggle joint for the driving of warp knitting equipment

A shackle toggle joint for driving a warp knitting machine comprising a housing of synthetic material having a metal ring (13) for holding a roller bearing (16) imbedded therein. The roller bearing (16) carries a joint bolt (11). The housing (12) further comprises a securing means in the form of a threaded bore (19) for holding a connecting element. There is thus obtained a higher working life for the roller bearing and a lower level of working noise.

BACKGROUND OF THE INVENTION 
The invention is directed to a shackle toggle joint for driving warp 
knitting equipment in a warp knitting machine, comprising a housing having 
(a) a transverse opening therein for the acceptance of a roller bearing 
carrying a hinge pin and (b) a retaining means for the attachment of a 
connecting element thereto. 
An example of a known shackle toggle joint is contained in the warp 
knitting machine model no. HKS 2 of Applicants' assignee. In this 
apparatus the housing of the shackle toggle joint is forged aluminum. The 
outer raceway of a roller bearing is pressed into the transverse opening 
of the forging. The shackle toggle joint is hinged, for example, inside a 
slot in a rocker arm which carries a needle bar, or other warp knitting 
machine apparatus. A hinge pin mounted within the roller bearing is 
attached to the body of the rocker arm on opposite sides of the slot in 
the rocker arm. 
SUMMARY OF THE INVENTION 
An object of the present invention is to increase the life of the 
components associated with a shackle toggle joint in a warp knitting 
machine. 
In a accordance with the illustrative embodiments demonstrating features 
and advantages of the present invention, there is provided a shackle 
toggle joint for driving warp knitting elements in a warp knitting 
machine. The shackle toggle joint has a connecting element and a housing. 
The housing is made of plastic material and has a retaining means for 
attaching this housing to the connecting element. The joint has imbedded 
in the housing a metal ring having a transverse opening. Also included is 
a bearing mounted in the metal ring and a hinge pin mounted in the 
bearing. 
By employing apparatus of the foregoing type an improved shackle toggle 
joint is achieved. In a preferred, joint the housing is made of a 
synthetic material such a plastic in which the metal ring for carrying the 
roller bearing is imbedded. This structure accommodates the substantial 
pressure forces that must be transferred via the shackle toggle joint and 
thus, also via the roller bearing. 
These forces arise because of the high knitting machine speed, which can 
require 40 cycles per second, wherein the direction of motion of a rocker 
arm must be altered rapidly to thus cause correspondingly high 
acceleration and deceleration forces. 
In accordance with the present invention, there is preferably provided a 
body of synthetic plastic material between the connecting element and the 
roller bearing, namely, the housing of the shackle toggle joint. This 
plastic body may be slightly deformed during and under the influence of 
the pressure forces. This small deformation is sufficient however, to 
reduce the peaks of the pressure forces. This in turn, leads to a 
substantial increase in the life of the roller bearing. 
A second advantage is obtained thereby. The synthetic material of the 
housing operates as a damper for the transfer of sound. Sound generating 
and sound radiating areas are thus separated from each other to a certain 
extent. Thus, the warp knitting machine operates somewhat more quietly. 
As a consequence of the foregoing deformability of the synthetic material, 
the outer raceway of the roller bearing could lack a firm base of 
attachment at the transverse opening. For this reason, a metal ring is 
rigidly anchored by being imbedded in the synthetic material of the 
housing and a roller bearing can be tightly fitted therein. 
Molding the synthetic material around the metal ring is advantageous. In 
particular, a zero pressure molding leads to very secure retention and the 
maintenance of the desired damping properties of the synthetic material of 
the housing. In this respect, knurling the outer circumference of the 
metal ring is desirable using an appropriate pattern such as spiral 
splines. In this manner the metal ring can be anchored absolutely securely 
in the synthetic material. 
Forming the metal ring from steel is particularly advantageous. Steel not 
only has a considerable rigidity, but also provides a long term, reliable, 
pressure seating for the roller bearing. As synthetic material for the 
housing, polyamides in particular, Polyamide PA 12 are particularly 
desirable, since they have the desired rigidity and also may be readily 
worked. 
In a preferred embodiment of the invention, the housing is attached to 
other mechanisms by a threaded bore substantially perpendicular to the 
axis of the roller bearing. This bore permits generated forces to be 
readily transmitted to the housing. 
Preferably, the housing has a slot extending laterally from the bore 
perpendicular to the axis of the transverse opening in the housing. Thus, 
the segments of the housing on either side of the slot may be squeezed 
together by tension forces from, for example, a screw or bolt. The 
diameter of the bore can be thereby slightly shrunk to achieve a very 
reliable retention of the threaded part of the connecting element in the 
bore. 
In a further embodiment, the housing in the area of the roller bearing can 
have a thickness corresponding thereto and in the area of the bore can 
have a greater thickness. Thus, the segments of the housing proximate to 
the bore, the slot and its tensioning arrangement are appropriately 
strengthened. 
In connection thereto, it is advantageous if the thickness transition of 
the housing is shoulder running in an arc concentrically around the roller 
bearing. This permits a substantially large angle of articulation between 
the connecting element and the rocker arm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A needle bar 1 is attached to the rocker arm 2, which is rotatable about an 
axle 3 fixed on the frame (not shown) of the knitting machine. The drive 
operates via a connecting element 4 in the form of a threaded rod, which 
is attached to a drive rod 6 by means of a nut 5. This drive rod 6 is 
reciprocated within the machine housing 8 by means of an unillustrated 
drive, for example, a pattern cam. The linkage between the drive shaft 6 
and the rocker arm 2 proceeds via a shackle toggle joint 9, which is 
mounted in slot 10 cut in rocker arm 2, whereby a joint bolt 11 is held in 
the slot 10 by the wall segments on both sides of slot 10 in rocker arm 2. 
As will be seen from FIGS. 2 and 3 the shackle toggle joint 9 has a housing 
12 of synthetic material suitably a polyamide. A metal ring, suitably a 
steel ring 13 having a generally cylindrical inside and outside, is 
imbedded in this housing 12. The outside of ring 13 has an external 
circumferential knurling 14, most suitably in the form of a toothed 
structure in the form of spiral splines. Consequently, molding performed 
at low or zero pressure can solidly embed metal ring 13 in housing 12. As 
used herein, knurling or a knurled surface includes splines, embossments, 
grooves, bumps, ridges or other means of providing an uneven surface that 
enhances the bonding between ring 13 and body 12. 
Metal ring 13 provides a transverse opening 15 in which the roller bearing 
16 is placed. Herein the outer raceway 17 of roller bearing 16 is press 
fitted into the transverse opening 15 while the joint bolt 11 is press 
seated in inner raceway 18. 
A retaining means is shown herein with a threaded bore 19 for receiving 
connecting element 4 whose axis is perpendicular to the axis of the 
transverse opening 15. The threaded end of connecting element 4 is screwed 
into bore 19 and is secured there by a locking nut 20. 
Slot 21 extends from bore 19 in a plane perpendicular to the axis of 
transverse opening 15. The slot 21 as illustrated in FIG. 3, extends from 
bore 19 to the right through the side wall of body 12. A tensioning means 
22 (FIG. 2) in the form of a bolt is inserted in threaded bore 23 in body 
12 to span slot 21 as illustrated in FIG. 2, so that both housing segments 
24 and 25 can be pulled together and thus provide a particularly secure 
hold between the thread of the bore 19 and the thread of the connecting 
element 4. 
In the vicinity of hinge pin 11, housing 12 has a breadth d, which 
corresponds to that of the metal ring 13 and roller bearing 16. In the 
vicinity of threaded bore 19 there is a greater breadth D so that 
relatively large clamping forces can be applied in the wall segments 24 
and 25. A shoulder 26 marking the transition between thicknesses d and D 
extends along a circular arc concentrically around the axis of the 
transverse opening 15 that is somewhat outside the remaining 
circumferentially oriented housing 12. This orientation permits a rather 
large angular articulation between the connecting member 4 and the rocker 
arm 2. 
Pressure testing of the shackle toggle joint shows that under pressure the 
polyamide is deformed approximately four times as much as forged aluminum. 
Under a maximum pressure load of 500 kilo-ponds, the aluminum housing is 
deformed by 0.035 mm and the polyamide housing between 0.1 and 0.2 mm, 
suitably by 0.140 mm. These pressure dependent deformations have 
substantially no effect upon the positioning of the working elements, 
however, in the case of the synthetic material, substantially reduce the 
pressure load on the roller bearings and furthermore, substantially reduce 
the noise of operation.