Holddown bar for textile-centering and -cutting machine

A holddown bar assembly for a textile-centering and cutting machine through which a web is advanced in a direction has a lower bar underneath the goods and extending transversely of the direction a full width of the web and an upper support bar above the goods, extending the full width of the web, and provided with a vertical guide. A row extending the full width of the web of finger plates are vertically displaceable relative to each other on the guide directly above the lower bar so that the web can be pinched between the row of finger plates and the lower bar. A biasing unit is engaged between the upper support bar and the finger plates for urging the finger plates downward against the web.

FIELD OF THE INVENTION 
The present invention relates to a holddown bar. More particularly this 
invention concerns such a bar used in a machine that centers and cuts 
textile goods. 
BACKGROUND OF THE INVENTION 
A standard towel-making machine advances a continuous web of textile goods 
having relatively long and thick pile zones separated by short 
transversely throughgoing and relatively thin pile-free zones or strips. 
The goods are advanced in steps and at each step a section is transversely 
cut from the leading end, with the cut in the middle of the pile-free 
strip. 
To correctly position the goods in the cutter a device such as described in 
German patent 3,431,210 (U.S. equivalent patent 4,609,182) is used. It has 
a pair of holder assemblies each comprising an upper and a lower holddown 
bar that flank the cutter in the transport direction of the goods and that 
can be brought into contact with the goods to clamp them and spread them 
under the cutter, centering the pile-free strip under the cutter. Due to 
the moderate elasticity of the goods being cut it is impossible to ensure 
that the pile-free strip will be perfectly centered under the cutter when 
the means that advances the goods stops each time. Thus the holders are 
closely juxtaposed with the cutter to start with. As soon as the goods 
stop, both upper bars are lowered to pinch the pile-free zone against the 
lower bar and then the holders are moved out-ward, sliding on the goods in 
the pile-free zone until they encounter the edge of the pile zone, 
whereupon they can no longer slip so that they stretch the pile-free zone 
tight between the two holders, perfectly centered under the cutter. The 
blade then drops or travels transversely across the thus centered zone to 
make the cut. 
Since the goods frequently have relatively thick longitudinal seams, it is 
necessary that one of the bars of each holder, normally the upper bar, be 
constructed to accommodate the welt formed by the seam. A rigid bar would 
not work as the thickened seam would hold it up so that it would not slide 
to and engage on the edge of the pile zone. Thus each upper bar is formed 
by a row of finger plates that are limitedly vertically displaceable 
relative to a rigid mounting bar that itself is displaceable vertically to 
bring the finger plates into and out of contact with the goods and 
longitudinally, that is parallel to the workpiece travel direction, to 
stretch out the pile-free zone and center it under the cutter. 
While such a system is relatively effective, it does not work well with all 
times of fabric. The upper holder bar can jump over the edge of the pile 
free zone on thinner looped goods. 
OBJECTS OF THE INVENTION 
It is therefore an object of the present invention to provide an improved 
holddown bar for a textile-centering and -cutting machine. 
Another object is the provision of such an improved holddown bar for a 
textile-centering and -cutting machine which overcomes the above-given 
disadvantages, that is which surely positions the finger plates on the 
goods for accurate stretching without skipping over the edge of even thin 
pile goods. 
SUMMARY OF THE INVENTION 
A holddown bar assembly for a textile-centering and cutting machine through 
which a web is advanced in a direction has a lower bar underneath the 
goods and extending transversely of the direction a full width of the web 
and an upper support bar above the goods, extending the full width of the 
web, and provided with a vertical guide. A row extending the full width of 
the web of finger plates are vertically displaceable relative to each 
other on the guide directly above the lower bar so that the web can be 
pinched between the row of finger plates and the lower bar. According to 
the invention a biasing unit is engaged between the upper support bar and 
the finger plates for urging the finger plates downward against the web. 
The biasing unit includes a flexible closed-end tube extending the full 
width of the web and bearing upward on the support bar and downward on the 
fingers and means for internally pressuring the tube with a fluid. 
Thus it is possible according to the invention to press the holddown 
fingers against the web with a force particularly tailored to the 
particular goods being centered and cut. When the pile is relatively deep 
and the goods are fairly soft, a low pressure is used while when the 
pile-free zone is relatively thin a higher pressure can be employed. 
Normally the tube is pressurized with air so that the same pressure is 
applied to each and every finger plate. 
The tube in accordance with the invention is above the finger plates. 
Furthermore the support bar forms a downwardly open groove extending the 
full width of the web and receiving the tube.

SPECIFIC DESCRIPTION 
As seen in the drawing a holddown bar assembly 1 for pile-type textile 
goods 2 is positioned adjacent a schematically represented cutter 12. The 
goods 2 are moved in a transport direction D and have a pile-free strip 2' 
and a pile zone 2". Although only one such bar assembly 1 is shown, 
normally such assemblies are used in pairs, flanking the cutter 12 in the 
direction D as described in the above-cited German patent and are 
limitedly movable in this direction by an actuator shown schematically at 
13. 
According to the invention the bar assembly 1 comprises a one-piece lower 
bar 3 and an upper support bar 4 carrying a plurality of vertically 
displaceable steel finger plates 5. The plates 5 are aligned in direct 
contact with one another and each have a small downwardly projecting 
finger 5' measuring some 4 mm wide (in the direction D), 2 mm thick, and 5 
mm high. Each plate 5 is formed with a vertically extending slot 6 in 
which engages a vertically extending guide plate 7 fixed to the holder bar 
4 so that these plates 5 can move freely vertically through a stroke 
substantially higher than the tallest pile likely to be encountered. 
The bar 4 is formed with a notch 15 having an upper surface 9 directed 
downwardly at upwardly directed upper surfaces of the plates 5 and a 
horizontally directed back surface 10 axially confronting a rear face of 
the plate 7 to form the downwardly open notch or groove 15 extending a 
full length of the bar 4. An elastic closed-end tube 8 is provided in this 
groove 15 and is connected to a compressor 11 or other inflating means. 
Thus in accordance with the invention once the bar 4 has been dropped by 
means such as a schematically illustrated actuator 14 down onto the 
pile-free strip 2', the tube 8 can be inflated to press the plates 5 
solidly down against this strip 2'. Thus they will engage it with 
substantially more force than that of gravity effective on their mass, but 
at the same time they will be able to fit around a seam or other bump in 
the goods without difficulty.