Stationary flat system for carding machines

A carding machine has a cylinder (3), stationary, self-cleaning flats (2) fixed at a chain (45) and guided and adjusted by a flexible bend (48). Additional active trash, dust and short fibre extraction units (1) are placed in the main carding zone. The units (1) are constructed as separate units, removable and placeable, instead of stationary flats (2), between adjacent flats (2). The units (1) have the same principal width gauge as the flats (2) or a multiple of it. The units (1) are fixed and held the same way as the flats (2) by the chain (45) and the flexible bend (48). The machine achieves an excellent carding quality and is readily adjustable to different needs.

BACKGROUND OF INVENTION 
The present invention relates to carding machines with a main cylinder, 
lickerin and doffer, comprising self-cleaning stationary flats with dust 
and trash extracting units in the main carding zone. 
Conventional carding machines use revolving flats that move around the 
peripheral surface of the upper part of the carding cylinder. Revolving 
flats are in general use for cotton carding because their flats can be 
cleaned when they are not opposing the surface of the carding cylinder. 
Cards equipped with revolving flats suffer from several disadvantages: 
Only a small number of the revolving flats is in the working zone. The 
revolving flats have only a temporary carding function as long as they 
pass over the working zone. The bigger part of the revolving flats is 
permanently not in a carding function. Therefore, the revolving flat card 
needs a large number of flats that are ineffectively used, cause higher 
costs and do not contribute to the carding effect. 
During their passage on the surface of the carding cylinder the clothings 
of the revolving flats become loaded with extracted material. For a large 
part of the working cycle therefore the carding efficiency of the 
revolving flats is considerably reduced or even ineffective. 
Each of the flats of the revolving card passes over the whole main carding 
zone and does not stay at a specific position. Therefore, all the flat 
clothings have to be identical to obtain a regular carding effect. A 
better carding effect is obtained with rougher flat clothings at the 
beginning and with finer flat clothings toward the end of the main carding 
zone, which is not possible with revolving flats. 
The bars of the revolving flats drag continually on the flexible bend, 
which guides the flats in the desired distance to the surface of the 
cylinder. The flexible bend, an important and expensive part of the 
revolving flat card, and the flats themselves suffer from considerable 
wear and tear which causes high maintenance costs. 
The revolving flat card requires a complicated construction for driving, 
guiding and cleaning which induces high costs for manufacturing and 
maintaining this type of card. 
These above described disadvantages gain importance when higher card 
productions are maintained. 
Several attempts have been undertaken to overcome these described 
disadvantages of the revolving flat card, the most important are the 
following: 
One of those attempts consists in improving the incomplete carding effect 
of the revolving flats by installing supplementary dust and trash removing 
devices on the cylinder surface outside the main carding zone. The major 
disadvantages of such approaches are: 
The additional elements do not remove the technological and mechanical 
disadvantages of the revolving flats in the main carding zone except that 
they subsequently compensate partially for their imperfect carding effect. 
Those additional elements further complicate the construction of the card 
and increase its manufacturing and maintaining costs. 
Another attempt to overcome the disadvantages of the revolving flat card 
consists in more radical solutions that replace the revolving flats by 
stationary flats. Stationary flats entirely replace their revolving 
counterparts, they are rigidly fixed to the main frame around a portion of 
the main cylinder and they do not move. 
Stationary flat cards have some major advantages: 
Cards with stationary flats are built without moving parts in the main 
carding zone beside the main cylinder. A simple general design and 
construction are therefore possible, which results in lower manufacturing 
and maintaining costs. 
All the stationary flats are permanently active in the working zone. 
Therefore, fewer flats are needed in comparison to the revolving flat 
card. All the flats can be permanently used. 
There is no motion of the bars of the stationary flats on the flexible 
bend, therefore wear and tear of those elements are avoided. 
No supplementary flat cleaning devices outside the main carding zone are 
necessary. 
The flat clothings can be adjusted to their position in the main carding 
zone. Rougher clothing's might be positioned at the beginning and finer 
clothings toward the end of the main carding zone. 
The flat position relative to the main cylinder can be individually set, 
thus additionally optimising the carding quality. 
Several approaches have been proposed to construct a stationary flat card, 
but each with some more or less severe disadvantages: 
U.S. Pat. No. 2,879,549 (1957) herein incoperated by reference uses a 
flexible bend to adjust the distance of the stationary flats to the 
cylinder surface. No extraction or cleaning devices are described. The 
stationary flats are not equipped with any wiring, clothing or such. A 
card like that will not result in sufficient carding quality of the 
passing staple fibres. Self-cleaning of the flats is claimed by the card 
wind in the sealed chamber of the whole main carding zone and by the 
replacement of the steel wire clothing of the flats with a non-loading, 
rigid, abrasive granular surface. No supply air from outside the card is 
used. As claimed, the extracted material has to pass under high pressure 
through the entire main carding zone. The state of the art is a flat 
clothing of steel wire or hooks, which is proven as inevitable for proper 
carding performance. The prescribed design severely impairs with the 
carding effect and therefore could not gain any attention in mill 
practice. 
JP-A-58-163731 A (1983) uses stationary flats fixed at a chain and on the 
flexible bend. Mote knife-like projections at the side of the flats and 
side clips, forming dust-sucking ducts, are used to separate dust, trash 
and short fibres and to remove them by the card wind after each flat. The 
details of design are not further specified. The main disadvantages of 
this solution are: no supply air from the outside of the carding zone is 
used, so that the exhaust air is not compensated. This induces distortion 
of the card wind and impairing the carding effect of following flats. The 
mote knife and the suction duct of separate attached parts at each flat 
require a complicated construction. The separate adjustment of the mote 
knifes of each flat is laborious and therefore impracticable for the use 
in mills. 
WO-A-89/00214 (1989) describes a waste removing device after the main 
carding zone of a revolving flat card, a mote knife, an air guiding plate, 
a sharp edge and supply air from outside the card together with the card 
wind to extract and remove remaining waste and short fibres from the 
cylinder surface. This solution uses a self-regulating air-stream with 
supply air and exhaust air. Being positioned after the main carding zone, 
it can work as extraction device neither for revolving nor for stationary 
flat clothings in the main carding zone. Being positioned after the main 
carding zone the device has no significance to the carding effect in the 
main carding zone. The design and shape of this extracting device make it 
non-applicable between flats in the main carding zone. 
U.S. Pat. No. 5,530,994 (1996) primarily claims a blade for trash removal 
with a rounded edge of a radius greater than 1 millimetre. Specially 
designed and shaped flats are shown, which differ from standard flat 
design. Extraction and removal devices between two stationary flats are 
shown. The exhaust air with the extracted dust, trash and fibres is 
removed laterally at one side of the extraction device, which requires 
eventually a pneumatic suction device. Each stationary flat is fixed 
directly to the main frame. The separate parts of the extraction device 
have to be adjusted individually for every flat which needs time and 
causes high adjustment costs. 
The straight blade for the mote knife together with the rounded edge does 
not give the optimum extraction effect as tests show. 
Supply air and exhaust air has to be regulated by adjustment means. The 
removal of the extracted material at the side of the extracting device 
might lead to an asymmetric extraction effect and thus should be avoided. 
The eventual need of a pneumatic suction device causes higher 
manufacturing and working costs. As each flat is fixed separately at the 
main frame of the card no common adjustment of the distance of the flats 
to the cylinder surface is possible. 
SUMMARY OF THE INVENTION 
The present invention avoids the above described drawbacks of the 
stationary flat system and offers full use of the inherent advantages. The 
invented flat system makes optimum use of the card wind, the fast moving 
air stream induced by the clothing of the main cylinder. Beside excellent 
carding quality the system offers a very effective extraction of trash and 
dust, the system being readily adjustable to the specific needs of a mill. 
In addition the invention gives an economical solution for manufacturing 
and setting the flat system. The necessarily accurate settings of the 
flats are easily achieved which is of considerable help in mill practice. 
The design uses standard card parts to a large extent, which reduces 
manufacturing costs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a side-view and partial cross-section of the main elements. 
The active extraction unit 1 is positioned in-between the stationary flats 
2 above the main cylinder 3 with the rotating direction 4. The surface of 
the cylinder 3 is covered--for example with a saw teeth clothing 5. The 
saw teeth are bevelled in the rotating direction 4 of the cylinder 3. The 
flats 2 consist of the bar 8 and the carrier 7 to which the flat clothing 
6 are fixed. As indicated the flat clothing 6 might be made out of 
metallic wires, also indicated as 6. The teeth of the metallic wires 6 are 
orientated against the rotating direction of the cylinder 3. As an 
alternative to the rigid metallic wires 6 flexible clothing might be used 
instead. The carding effect between the flat clothing 6 and the saw teeth 
of the cylinder surface 5 is regulated by the specifics of the clothings 
and by finely adjusting the distance between the flat clothing 6 and the 
cylinder clothing 5. The staple fibres (not shown) are carded in a 
standard way between the cylinder clothing 5 and the flat clothing 6. 
The cylinder 3 with a standard diameter of about 1.2 m is running at 300 to 
500 revolutions/min. in the direction 4. For example at 400 
revolutions/min. The circular velocity of the cylinder clothing 5 amounts 
to approximately 25 m/sec. Thus the fast running cylinder creates a strong 
air stream on its surface in the direction 4, the so called card wind 32. 
The extraction unit 1 is shown as a compact structure without direct 
connection to the adjacent flats 2. The rubber seal 9 is inserted in the 
side grooves. The rubber packing or seal 9 touches the therefore 
neighboring extraction unit 1 or the flat 2 to seal the gaps 11 and 26. 
The sealing of the gaps 11 and 26 prevents the card wind 32 from escaping 
through the said gaps. 
FIG. 1 further explains the design of the extraction unit 1. The compact 
casing of the extraction unit 1 consists of the side sheets 12, 13, the 
cover plate 14 and the central bar 20. Screws 21 fix the side sheets 12, 
13 laterally to the central bar 20. Screws 23 fix the cover plate 14 to 
the central bar 20 on both sides of the suction hood 22. Central bar 20 
and side sheets 12, 13 form mutually the exhaust air channel 30. The side 
sheet 12 together with the opposite side of the adjacent flat bar 8 
defines the supply air channel 27. 
The rounded edge 15 of the side sheet 12 acts as air flow and fibre 
deflector. Section 16 of the side sheet 12 acts as hold-down means for the 
fibre material against the clothing 5 of the cylinder 3. The angular bent 
section of the side sheet 13 with the acute-angled edge 19 serves as mote 
knife 18 that extracts trash and short fibres from the carded fibre 
material. Thus the working parts of the side sheets 12, 13 (the rounded 
edge 15, the hold-down section 16 of the side sheet 12, and the mote knife 
18 with the acute-angled edge 19 of the side sheet 13) are integrated 
sections of these side sheets. Each of the side sheets 12, 13 consists of 
a sheet metal of approximately 0.5 mm to 3 mm width. 
A special feature of the invention is the position of the inserted 
extraction units 1: the extraction units 1 have the same principle width 
as the flats 2. This means that the width of an extracting(unit 1 plus the 
width of the supply air channel 27 equals the width of a flat 2 plus the 
width of one gap 26 between two flats 2. The distance between the fixation 
points 24 of two adjacent flat bars 8 equals the distance between the 
fixation point 25 of the extraction unit 1 and the fixation point 24 of an 
adjacent flat bar 8. This same principle width of the extracting units and 
the flats allows the replacement of flats by extraction units and vice 
versa as desired. 
In mill practice the extracting effect of the extraction units 1 has to be 
adjusted according to the specific material processed and the quality 
parameter needed. For this purpose the compact extraction units 1 can be 
replaced by exchange of extraction units with different dimensions of the 
side sheets 12, 13 acting as hold-down means 16 and mote knife 18. Such an 
exchange of the extraction units allows a more accurate overall adjustment 
of the distance of the hold-down means 16 and the edge 19 of the mote 
knife 18 to the surface of the cylinder 3 than the individual adjustment 
of several separate working parts of a non-compact extracting device. The 
exchange of the whole extraction unit 1 is also much less labour-intensive 
than the adjustment of an extraction device, whose separate parts have to 
be adjusted individually to change the extraction effect. 
The air flow is of great importance for the proper function of the entire 
system. The supply air 33 is sucked by the card wind 32 through the supply 
air channel 27 to the rounded edge 15 of the side sheet 12. The supply air 
33 is then accelerated by the nozzle effect in the narrowed passage 28 
between the hold-down section 16 and the clothing 5 on the surface of the 
cylinder 3. This acceleration of the air stream at the passage 28 
reinforces the removing effect of the air stream to dust, trash and short 
fibres which are subsequently separated from the good fibres. The good and 
usable fibres remain in the clothing 5 while trash and dust are removed by 
the acute-angled edge 19 of the mote knife 18 of the side sheet 13. 
The extracted material is then sucked away in the exhaust air 34 through 
the exhaust gap 29 between the edge 17 at the end of the hold-down section 
16 and the acute-angled edge 19 at the end of the mote knife 18, through 
the exhaust air channel 30, through the outlet 31 and the suction hood 22. 
The edge 17 of the hold down section of the side sheet 12 is a straight 
edge, treated free from fibre sticking. 
The extraction unit 1 can be characterised as active because the whole air 
stream--from the supply air 33 to the exhaust air 34, which carries the 
extracted material through the exhaust gap 29, the exhaust air channel 30 
and the outlet 31--is generated, driven and maintained by the card wind 
32. No additional mechanical or pneumatic ventilation or suction device is 
necessary to activate this air stream and thus to extract dust, trash and 
short fibres in the main carding zone and to remove the extracted 
material. Therefore, the extraction units according to this invention are 
called as self-ventilating. 
The extraction unit 1 extracts and removes the dust, trash and short fibres 
from the narrow passage 28 through the exhaust gap 29 to such a degree 
that only the card wind 32 and good fibres in the saw teeth clothing of 
the cylinder surface 5 pass to the carding zone of the next flats 2 in the 
cylinder rotating direction 4. The clothing's 6 of the flats 2 after the 
extracting unit 1 do not become loaded with dust, trash and short fibres 
and act therefore with their full carding effect. No other cleaning 
devices are necessary for the cleaning of the clothing's 6 of the 
stationary flats 2. Therefore, the present invention realises a 
self-cleaning card with stationary flats 2 by the active extraction units 
1. 
The volume of the supply air 33 entering into the extraction unit 1 equals 
the volume of the exhaust air 34 leaving the extraction unit 1. This is 
attained without additional regulating devices for the supply air 33 at 
the supply air channel 27 or for the exhaust air 34 at the outlet 31. This 
self-regulation of the exhaust air stream 34 is effected by the volume and 
the shape of the exhaust air channel 30. 
Because the supply air 33 to the extraction unit 1 equals the exhaust air 
34, the air stream 33, 34 through the extraction unit 1 does not interfere 
with the air stream of the card wind 32. Thus the card wind 32 passes 
under the extraction unit 1 without distortion and streams further to the 
next flats 2. The self-regulation of the supply air 33 and the exhaust air 
34 and their non-interference with the card wind 32 are essential for an 
optimal downstream carding effect of the next flats and for the extracting 
effect of the following extracting unit 1. 
FIG. 2 shows the front-view of the extraction unit in the opposite 
direction to the cylinder rotating direction 4. The side sheet 13 is 
laterally fixed to the central bar 20 with numerous screws 21. The central 
bar 20 consists of massive Aluminium. The screws 23 fix the cover plate 14 
to the top of the central bar 20. The hole 38 is positioned at the lateral 
centre 39 of the extraction unit, where the suction hood 22 is joined to 
the cover plate 14 over the hole 38. 
FIG. 2 shows the compact structure of the extraction unit as a special 
feature of the present invention. This compact structure of the extraction 
unit consist substantially of only three main elements: the central bar 
20, the side sheet 12 (not shown), and the side sheet 13. The end part 37 
of the central bar 20 contains the fixation screw 41 that fixes the 
extraction unit to the chain (not shown). The under surfaces 35 of the two 
central bars 20 serve as cover of the exhaust air channel 30. The inner 
surfaces 36 of the two central bars 20 build the side covers of the outlet 
31. The extraction unit contains no movable parts. Each of its few main 
parts serves for different functions. All parts of the extraction unit 
have shapes that are easy to manufacture. 
The exhaust air 34 sucks away the extracted dust, trash and short fibres 
over the whole length of the exhaust air channel 30, which equals the 
carding width of the clothing on the cylinder surface. The exhaust air 34 
streams through the exhaust air channel 30 and then out of the extraction 
unit through the outlet 31 and the hole 38 into the suction hood 22. The 
outlet 31 and the suction hood 22 are positioned at the lateral centre 39 
of the extraction unit. Therefore, the exhaust air 34 is focused to a 
continued air stream that further removes the extracted material out of 
the extraction unit. 
The exhaust air channel 30 acts as a suction chamber to the exhaust air 34. 
The volume and the shape of the suction chamber are chosen so that the 
exhaust air 34 does not interfere with the air stream of the card wind, 
and that the exhaust air 34 optimally removes the extracted material. If 
the volume of the suction chamber of the exhaust air channel 30 is too 
big, the air stream becomes too slow to remove the extracted material. If 
the volume of the suction chamber of the exhaust air channel 30 is too 
small, the volume of the exhaust air 34 is not sufficient to remove all 
the extracted dust, trash and short fibres. Additional supply air 40 may 
be provided optionally from the outside of the card through the inlet 42 
into the exhaust air channel 30. The inlet 42 would then be positioned at 
both sides of the exhaust air channel 30 to secure a symmetrical provision 
of additional supply air 40. 
FIG. 3 shows an example of the main carding zone with a configuration of 
one extraction unit 1 after each group of two stationary flats 2. In this 
example 28 stationary flats are continually and completely cleaned by 14 
extraction units 1. These 28 flats are therefore permanently in optimal 
carding action. 
As explained, each extraction unit 1 is fully interchangeable with any flat 
2. Therefore, any other configuration of the system is possible, as 
required for an optimal carding and cleaning effect in the main carding 
zone. By this the carding effect in the main carding zone is so effective, 
that in most cases no supplementary carding or extracting device is 
necessary before or after the main carding zone. This contributes further 
to an uncomplicated and economic construction of the card with 
self-cleaning stationary flats, reducing its manufacturing and operation 
costs. 
A removal hose 43 is fixed at the suction hood 22 of each extraction unit 
1. The removal hoses 43 lead to the central collecting hose 44. The 
exhaust air 34 removes dust, trash and short fibre out of every extraction 
unit 1 through the suction hood 22 and the removal hose 43 into the 
collecting hose 44. 
The extracted material is completely collected and removed from the main 
carding zone in a closed circuit. No flying dust, or short fibres leave 
the main carding zone sidewise or over the top of the flats. Therefore, 
the pollution of the card by flying dust, trash and short fibres from the 
main carding zone is prevented. This saves a substantial part of the 
otherwise necessary manual card cleaning and prevents card operation stops 
for manual cleaning of the respective card elements. The costs for 
periodical manual cleaning of the card are thus substantially reduced. 
This further reduces carding operation costs because periodical machine 
stops for manual cleaning are reduced to a large extent. 
The chain 45 is conventional for revolving flat cards. The described 
invention uses the chain 45 to hold the flats 2 as well as the extraction 
units 1 tangential and to pull them against the flexible bend 48. The 
flexible bend 48 keeps the flats 2 and the extraction units 1 radial in 
the desired distance from the surface of the main cylinder 3. The main 
cylinder 3, rotating in the direction 4, presses the flats 2 and the 
extraction units 1 away from its surface and thus against the chain 45. 
These counteracting forces of the main cylinder 3 rotating in the direction 
4, of the chain 45 and of the flexible bend 48 allow to adjust with great 
precision the desired distance of the flats 2 and of the extraction units 
1 to the surface of the main cylinder 3. The adjustable flexibility of the 
flexible bend 48 per segment allows distinctive adjustments of this 
distance for groups of flats 2 and extraction units 1 at different 
segments of the flexible bend 48. Such a precise and differentiated 
adjustment of the distance of the flats 2 and the extraction units 1 to 
the surface of the main cylinder 3 is essential for an optimal carding and 
cleaning effect. 
The chain 45 extends over the whole main carding zone and is tensioned 
between the back support 46 and the front support 47. The chain 45 and the 
flexible bend 48 allow a common adjustment of the distance to the cylinder 
surface of all the flats 2 and extraction units 1 in the main carding zone 
by a few simple manipulations. Thus the separate adjustment of each flat 2 
and of each extraction unit 1 is replaced by a time saving common 
adjustment operation for the whole main carding zone with the chain 45 and 
the flexible bend 48. This saves a lot of time and costs for the 
individual adjustment of each flat 2 and extraction unit 1 to the cylinder 
3, that is only possible when the card operation is stopped. Therefore, 
the common and simple adjustment of all the flats 2 and extraction units 1 
in the main carding zone considerably reduces downtime of the card and 
thus its operation costs. 
FIG. 4 gives details of the fixation of the flat 2. The fixation screw 41 
in the bolt 51 fixes the flat bar 8 at the chain 45. The flat bar 8 lies 
on the upper surface 50 of the flexible bend 48, which is radially 
adjustable at the main frame 49. This allows the conventional adjustment 
of the distance of the flat clothing 6 to the surface 5 of the main 
cylinder 3 with the flexible bend 48. The main carding zone is covered by 
the card cover 52. 
FIG. 5 shows further details of the fixation of an extraction unit 1 and a 
flat 2 at the chain links 53. The bolt 51 is inserted into the link hole 
of two overlapping chain links 53. The fixation screw 41 through the bolt 
51 in a groove, either in the bar 8 of the flat 2 or in the central bar 20 
of the extraction unit 1, connects the flat 2 or the extraction unit 1 
with the chain links .53. Thus the flat 2 and the extraction unit 1 are 
fixed with the described identical means at the chain links 53 of the 
standard chain 45. Therefore, it is possible to replace flats 2 by 
extraction units 1 in a simple operation. 
The top-view of the extraction unit 1 in FIG. 5 shows also the lateral 
fixation of the side sheets 12, 13 to the central bar 20 with the screw 
21. 
FIG. 6 shows the tension device of the chain 45 in detail. The chain head 
56 of the tension piece connects the last chain link 53 to the tension 
piece 57 that passes through a hole in the bow 58 of the front support 47. 
The base plate 54 fixes the front support 47 with the screw 55 to the main 
frame 49 of the card. The chain 45 is tensioned by turning the hexagonal 
nut 60 at the adjustment screw 60 that acts on the tension spring 59. This 
pulls the tension piece 57 in the cylinder rotating direction 4, thus 
tensioning the chain 45 over the whole main carding zone. Also shown is 
the identical fixation of the extracting units 1 and the flats 2 at the 
chain links 53 with the fixation screw 41.