Mechanical multiplier for weaving looms

The present invention concerns a mechanical multiplier for weaving looms, for instance for the drive of rapiers or lances, of the head frames or such like.

Several devices have already been suggested for driving the grippers of 
rapier looms. In some of these devices, the grippers are attached each to 
the end of a flexible lance or strip, whereby these lances and grippers 
are displaced synchronously in a reciprocating movement. 
Considering that these grippers have each time to travel over a relatively 
large distance, at as high a speed as possible, and such in complete 
synchronism with the movements of the other parts of the loom, the problem 
of the drive for aforesaid lances is not without difficulty, all the more 
so as the driving device must occupy as small a space as possible. 
The purpose of the invention is to offer a solution to the above-described 
problem. 
Consequently, a mechanical multiplier is suggested, which consists mainly 
of the combination of a driven rocker lever, a gear which engages the part 
to be driven, a pinion which is solidly attached to aforesaid gear, and a 
flexible element such as a belt, a chain or suchlike, which engages 
aforesaid pinion, which passes over two rollers fitted at one end of 
aforesaid rocker lever, and of which both ends are attached to fixed 
points of the device. 
Such a device can be fitted at one end of the slay of a weaving loom. When 
two rapiers or lances are used, with transfer of the weft thread from one 
gripper to the other at the center of the slay, two devices according to 
the invention are used, one at each side of the slay. 
The advantages of the driving device according to the invention are mainly 
: a very simple and sturdy construction; a relatively light weight; low 
inertia and a limited space requirement due to the small amplitude of the 
movement of aforesaid rocker lever.

As shown in FIG. 1, the device 1 according to the invention is fitted in a 
casing 2 which is attached to one end of the slay 3, at the level of the 
slay sword 4, and is fitted rotatably around the shaft 5 of the slay. 
In casing 2, a shaft 6 is provided, upon which are rotatably fitted a 
rocker level 7, on the one hand, and a gear 8 with pinion 9, on the other 
hand. 
On the end of rocker lever 7, which is furthest removed from shaft 6, two 
guiding rollers or wheels 10 and 11 are rotatably fitted. 
A flexible element 12, such as a chain, a toothed belt or suchlike, is 
attached at one of its ends to a fixed post 13 of the device and is then 
led over roller 11, pinion 9 and roller 10, whereby its other end is 
attached to a further fixed post 14 of the device. 
The rocker lever 7 is provided with a laterally protruding arm 15 which is 
connected to driving means which are not shown, whereby lever 7 is 
alternately rotated from one of its end positions (full line in FIG. 1) to 
the other (dash-dot line in FIG. 1). 
Gear 8 engages a perforated rod or lance 16 (FIG. 2) which is guided by 
guiding devices 17 and 18. This rod or lance 16 may for instance be 
fabricated from a strip of flexible plastic, which in itself is well 
known. 
The above-mentioned fixed posts 13 and 14 may each consist of a sleeve 19 
fitted around a pivot 20 with interposition of a rubber bushing 21. The 
latter permits a slight rotation of sleeve 19 due to which no too great 
stresses occur in the belt or chain 12 during the displacements of rocker 
lever 7. 
The driving device thus described is therefore extremely simple and takes 
up very little space. With respect to known driving devices with the same 
purpose, it offers the advantage of slight weight, and consequently of low 
inertia, and such notwithstanding a ratio between input and output 
movements of more than 1 to 10. 
It is obvious, that various alterations can be applied to the form of 
embodiment described as example, without going beyond the scope of the 
invention. 
The invention also extends to weaving looms which are equipped with at 
least one driving device as described above, or respectively as defined in 
the following claims.