Electro-pneumatic loom shedding system

A manual loom can be complemented by a device which makes possible computer-controlled weaving even in such simple looms. The device comprises a PC, a printed board control and a module block having air cylinders with appurtenant pistons which bear the weighted lifting rods for the warp threads.

FIELD OF THE INVENTION 
The invention relates to a device for use in a loom for raising warp 
threads in accordance with a desired weave pattern by means of weighted 
lifting rods. 
BACKGROUND OF THE INVENTION 
Industrial looms have undergone rapid development, from the introduction of 
punched card control to today's machines, which, in step with the general 
trend within electronics and computer technique, have evolved into fully 
electronic, computer-controlled machines. The state of the art of today's 
computer design systems makes it possible inter alia to control data media 
for electronic Jacquard machines as well as to control a large number of 
electronic Jacquard machines via a network computer, and also makes it 
possible, of course, to develop and process Jacquard designs as desired. 
SUMMARY OF THE INVENTION 
It is an objective of the present invention to make possible the use of 
computer technique in a simple and inexpensive manner also for manual or 
hand looms. The term "manual looms" is used to mean looms of the type 
found in homes, the type used by interested amateurs and also by 
craftspersons, i.e., looms which on the whole are intended for the 
production of individual items. Looms of this kind have a relative simple 
structure, and the pre-setting of the loom for desired raising (shedding) 
of the warp threads in accordance with a desired weave pattern, is 
relatively time-consuming, although today there are suitable punched card 
systems, and systems based on computer technique, so that the weaver can 
produce virtually all possible designs in the weave--designs which can be 
drawn according to need on a PC screen. 
The easiest way to implement the invention is to use a cylinder/piston 
module with single top valves, controlled by respective superjacent 
solenoids. The module is realised most easily as a cylinder block of an 
appropriate material, where a desired number of parallel cylinders are 
drilled out, in which a respective piston with attached lifting rod is 
placed. A common chamber is provided above this cylinder block where the 
solenoids are located, above their respective valves. This common chamber 
can be put under negative pressure or positive pressure. Atmospheric 
pressure acts on the underside of the respective pistons and actuates 
these in an upward direction. When a piston ascends it will take a warp 
thread with it. Which valves are to be opened is determined by the design 
drawn on the PC screen, via printed card control which activates the 
appropriate solenoids. As soon as the weft is finished, the pistons are 
caused to descend into the starting position. Thus, the cycle continues. 
Several modules can be arranged one after the other, laterally or in the 
longitudinal direction of the loom, thereby covering a larger area, with 
the possibility of weaving everything from narrow bands to wide woven 
cloths, up to the maximum width of the loom. 
The new device is simple, inexpensive and can be adapted readily to an 
ordinary simple loom.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1 illustrates the principle of a computerized loom device where the 
invention can be used. A design control, a weave control and a lifting 
system are all to be found in the figure. 
The design control is in reality a PC, while the weave control comprises a 
printed card control and a necessary pump for the provision of negative 
and positive pressure. The lifting system comprises a cylinder block. In 
practice, the cylinder block and the valve block will be constructed as 
one, as can be seen in FIG. 3. In addition, reference is made to the 
explanatory text in FIG. 1. 
In FIG. 1 a cylinder block 1 is shown. The broken lines indicate how 
additional similar blocks 2,3 and 4 can be juxtaposed with the block in 
the warp direction, as determined by the warp threads 5. The individual 
blocks or modules can also be placed side by side, that is transverse to 
the warp direction. 
In each block 1 there is a plurality of cylinders with appurtenant pistons, 
and these pistons in turn are attached to respective lifting rods 6. Each 
such lifting rod has in a known way a warp thread eyelet 7 and is weighted 
with a suitable weight 8. 
FIG. 2 is a simplified side view of a loom 9. The warp threads are 
indicated by means of the reference numeral 5. Each warp thread is 
attached to a lifting rod 6 in that the thread is threaded through an 
eyelet 7 in the lifting rod. The lifting rod 6 bears a weight 8. The 
lifting rod 6 ascends in a cylinder block 1. This cylinder block 1 is 
suspended in the loom by means of a suitable supporting stay 10. On the 
top of the cylinder block 1 is a common chamber 11. This housing forms a 
common chamber for the cylinders in the cylinder block. 
FIG. 3 is a schematic section through the block 1 with appurtenant common 
chamber 11. The block and the common chamber together form a module which 
may contain a desired number of cylinders. In the drawings, the module is 
shown having a single row of laterally placed cylinders, but a module can, 
of course, contain several parallel rows of cylinders, for example, three 
times 20 cylinders. 
In the schematic section in FIG. 3, it can be seen that the cylinder block 
1 has a through-going cylinder 12. In the cylinder 12 there is placed a 
piston 13 with a downwardly projecting lifting rod 6. 
A common chamber 11 is provided on the top of the cylinder block 1. A 
plurality of solenoid-operated valves 14 are placed herein, one for each 
cylinder 12. Electric current is supplied to the winding 15 of the 
solenoid through the electric leads 16,17. The common chamber 11 is 
connected to a pump device through the indicated connecting pipe 18. 
The solenoid-operated valve is shown on a larger scale in FIGS. 4 and 5. 
The valve 14 is constructed having a housing body which comprises the 
solenoid core 19 with appurtenant winding 15. The housing body is on an 
intermediary 20, which is designed for insertion into the upper open end 
of the cylinder, see FIG. 3. There are holes 21 for the passage of air to 
the cylinder 12 in the intermediary 20. There is a blind bore 22 (see FIG. 
5) in the intermediary 20 wherein the armature or valve stem 22 passes. 
The valve stem 22 has an annular groove wherein an `O` ring 23 is placed. 
The said `O` ring is located inside the interior of the housing body, 
wherein above the `O`ring there is a valve seat 24. Holes 25 for the 
passage of air are provided immediately above the valve seat 24. 
In FIG. 4 the valve is shown in a no-current state and it is open, the `O` 
ring 23 being spaced apart from the valve seat 24. In FIG. 5 the armature 
or valve stem has been drawn in as a result of the solenoid having 
received an electric pulse, and the `O` ring 23 now rests in a sealing 
fashion against the valve seat 24. The valve is closed. 
The thread control functions in the following manner. 
As mentioned, the valve 14 is located on the top of a respective cylinder 
12. The valve is in a common chamber which is connected to a pump device, 
see FIG. 1. In the individual cylinder 12 there is a piston 13 which is 
connected to a thread in the loom by means of the lifting rod 6. When the 
valve is open and the common chamber is put under negative pressure, the 
air will be drawn out of the cylinder and will draw the piston 13 up. The 
underside of the piston is actuated by atmospheric pressure. 
In a module a great number of valves and cylinders are mounted or formed 
side by side in a block. All the valves can be operated independent of one 
another. 
If a piston 13 is to be down while the others are raised, the following 
happens: 
Slight negative pressure is applied in the common chamber 11, but not 
sufficient to cause the piston to be raised. 
The control system sends an electric pulse to the valve 14. 
The armature or valve stem 22 is raised. 
The `O` ring 23 on the valve stem 22 will seal against the valve seat 24. 
The negative pressure above the `O` ring 23 causes the valve stem to be 
held up, even after the solenoid or electromagnet has stopped working. 
The pressure on the underside of the valve stem will be approximately 
atmospheric pressure owing to a small leakage between the piston and the 
cylinder. 
When a greater negative pressure is applied (lifting negative pressure), 
the piston in question will remain down whilst the others are raised. 
To re-set the system, positive pressure is applied in the common chamber 
11, the valve stem 22 will fall down and the valves 14 are opened.