Card having a hold-down means

Abstract

The present invention relates to a card (100) comprising a drum (4) and a revolving flat (17) having flat bars (20) extending around part of the circumference of the drum (4), wherein: the flat bars (20) are guided on both sides at a distance from one another by means of belts (24) and, with their sliding elements or pins (20a), are moved along a sliding strip (18); the belts (24) are guided over at least two deflection rollers (21); and a hold-down means (25) is disposed in the region of the transition of the flat bars (20) from the sliding strip (18) over the deflection roller (21) or in the region of the transition from the deflection roller (21) onto the sliding strip (18), which hold-down means is designed to press the flat bars (20) against the sliding strip (18). The invention is characterised in that the hold-down means is designed to compensate for a carding gap change between the clothing of the drum (4) and the clothing of the flat bars (20).

Description

[0001] Title: Carder with a hold-down device

[0002] Description

[0003] The present invention relates to a carding machine comprising a drum and a revolving flat with flat bars encircling a portion of the circumference of the drum, according to the preamble of claim 1.

[0004] When cleaning or carding fiber material, e.g., cotton and / or man-made fibers, stationary or rotating cleaning or carding elements are usually placed opposite a rotating roller equipped with a clothing. To achieve a good cleaning or carding effect, these elements must be positioned as close as possible to the clothing of the rotating roller. Adjustment is performed in the cold state and with the roller stationary. The effective distance between the tips of a clothing and a carding element opposite the clothing is called the carding gap. The carding gap is crucial for carding quality. The size (width) of the carding gap is an essential machine parameter that influences both the fiber processing technology and the running behavior of the machine. The carding gap is set as narrow as possible without the risk of a collision between the working elements.To ensure consistent fiber processing, the gap must be as uniform as possible across the entire working width of the machine. The carding gap is influenced primarily by the machine settings on the one hand and the condition of the carding clothing on the other. The most important carding gap of the revolving flat card is located in the main carding zone, i.e., between the cylinder and the revolving flat unit. At least one carding clothing adjacent to the working gap is in motion, usually both.

[0005] The revolving flat system, which forms the main carding zone with the drum, consists of a large number of flat bars that are guided circumferentially along the drum. The circular movement of the flat bars is achieved by a driven rotating belt, with which the flat bars interact at their end faces by means of pins or guide elements. The belt is guided over two deflection pulleys, at least one of which is driven. In the area of ​​the drum, the flat bars are guided over an arc-shaped bar, the coaxial distance of which from the drum is adjustable. When a flat bar travels downwards over the arc-shaped bar, which is also called a flexible bend depending on the design, it tends to tip over at a certain angle due to its center of gravity. The belt, which is stretched over the arc-shaped bar, generates a contact force on the flat bar, which prevents this tipping.Shortly before the deflection wheel, before the flat bar leaves the guide area of ​​the curved bar, the belt runs tangentially away from the curved bar. In this area, the belt no longer exerts any pressure on the flat bar, and it can tilt. This increases the carding gap at this point, and effective carding is no longer guaranteed.

[0006] EP 0753610 B1 discloses a drive belt for flat bars. It has two webs on one side of the belt for each flat bar, which interact with a sliding element on the end faces of the flat bars. The webs function as a snap connection and interact with the flat bars in a form-fitting manner, thus preventing the flat bars from lifting off at the end of the curved strip.

[0007] It is well known that so-called hold-down devices are used in the deflection area shortly before the flat bars are lifted from the slide bar to the deflection roller to guide the flat bars so that the carding gap remains constant for as long as possible. Current hold-down devices are either very static and act only as an overhead guide, or they feature a complex pressure system for multiple hold-down devices, which is very complex and expensive to implement today with the multitude of sensors installed.

[0008] The object of the invention is to further develop a carding machine in which an improved hold-down device ensures simple guidance of the flat bars up to the deflection roller of the revolving flat.

[0009] This object is achieved by a device and a flat bar according to the preamble of claim 1 in conjunction with the characterizing features. Advantageous developments of the invention are specified in the dependent claims.

[0010] The invention according to claim 1 relates to a carding machine with a drum and a revolving flat with flat bars encircling a portion of the circumference of the drum. The flat bars are guided at a distance from one another on both sides by means of belts and moved along a slide bar with their sliding elements or pins. The belts are guided around at least two deflection rollers, with a hold-down device being arranged in a fixed position in the area where the flat bars transition from the slide bar around the deflection roller or in the area where the deflection roller transitions to the slide bar. The hold-down device is designed to press the flat bars onto the slide bar.

[0011] The invention includes the technical teaching that the hold-down device is designed to compensate for a carding gap change between the clothing of the drum and the clothing of the flat bars. This makes it possible to keep the carding gap constant along the slide bar up to its end regions, regardless of the size of the carding gap. The hold-down device has a support element with an upper side, two end faces, and a lower side, wherein the lower side is concave and acts with a compressive force on the sliding elements or pins of the flat bars. The compressive force in the deflection area of ​​the flat bars presses these onto the slide bar, preventing tilting of the flat bars and maintaining a constant carding gap.

[0012] The compressive force can be generated by at least one spring element. Alternatives to the spring elements can be pneumatic or hydraulic pressure cushions, or any actuators, which can also be controlled if necessary.

[0013] The hold-down device is designed in such a way that the concave underside of the hold-down device, which presses the sliding elements or pins of the flat bars onto the slide bar, varies in distance from the top side. The variation in the distance between the top and bottom of the hold-down device can be achieved by a pressure element or at least one spring element.

[0014] Because the underside of the hold-down device is attached to the support element or to the top of the hold-down device by means of at least one spring element, the change in the carding gap can be compensated for via the spring travel without further adjustment of the hold-down device. Depending on the design and construction of the at least one spring element, the pressure force on the sliding elements or pins of the flat bars can be kept almost constant.

[0015] Preferably, the at least one spring element can consist of an elastic plastic or of several spring elements which are designed as a compression spring, leaf spring or disc spring.

[0016] The at least one spring element can have an increasing spring force from the center of the hold-down device to one end face, since the greatest tilting moment acts on the flat bars in the end area of ​​the hold-down device, and thus the highest contact pressure is required here. The end face with the increasing compressive force is located in the area where the flat bars transition from the slide bar around the deflection roller or in the area where the slide bar transitions.

[0017] The hold-down device, including the support element, the top side, and both end faces, can be designed as an open, one-piece or single-piece shell. This shell can be made, for example, of a high-strength plastic and is preferably electrically insulating. This prevents faulty contact or short circuits, which could lead to a card shutdown, from occurring in the deflection area of ​​the revolving flat during electrical carding gap control. Because the missing open side of the shell is formed by the underside, this can be adjusted at a varying distance from the top side of the hold-down device using pressure force or spring elements.

[0018] Preferably, the at least one spring element is arranged in the open shell of the hold-down device, so that a compact component is created to which few fibers can adhere during continuous operation.

[0019] Preferably, stops are arranged on the hold-down device to prevent the springs from rebounding.

[0020] The hold-down device can be attached to a side plate, a flexible bend, an adjusting flange, or at least one contact element of the card using fastening elements. It can thus be easily installed and replaced as a wear part. The hold-down device can be symmetrical or asymmetrical. With a symmetrical design, the pressure or spring force can be adjusted at one end face.

[0021] The hold-down device according to the invention for use on a carding machine is designed to compensate for a carding gap change between the clothing of the drum and the clothing of the flat bars. It has the features of one of claims 2 to 11.

[0022] Further measures improving the invention are described in more detail below together with the description of a preferred embodiment of the invention with reference to the figures.

[0023] They show:

[0024] Figure 1: A schematic side view of a carding machine with the inventive

[0025] Device;

[0026] Figure 2: A perspective enlarged view of a deflection area of ​​the revolving lid;

[0027] Figure 3a: A hold-down device from the front;

[0028] Figure 3b: A hold-down clamp from the back.

[0029] Fig. 1 shows a carding machine 100 according to the prior art, in which fiber flocks are guided via a chute to a feed roller 1, a feed table 2, via several licker-in devices 3a, 3b, 3c, to the drum 4 or the reel tambour. On the drum 4, the fibers of the fiber flocks are parallelized and cleaned by means of stationary carding elements 13 and rotating flat bars 20 arranged on a revolving flat 17. The belt 24 of the revolving flat 17, not shown here, is guided over several deflection rollers 21, in which the invention is explained in the area of ​​the deflection roller 21 shown here on the right using the next figures. The resulting fiber web is then conveyed via a doffer 5, a stripping roller 6 and several squeezing rollers 7, 8 to a fleece guide element 9, which forms the fiber web with a funnel 10 into a fiber band, which is transferred via take-off rollers 11, 12 to a subsequent processing machine or a can 15.The adjustment of the flat bars 20 to the drum 4 (carding gap) is carried out via a flexible bend 23 (not shown here) or sliding strips 18, which can have wedge-shaped elements aligned against one another.

[0030] Figure 2 shows the area of ​​a deflection roller 21 in detail. A flexible bend 23 is arranged and secured to a side plate 16 of the carding machine by means of adjusting spindles 19, so that the flexible bend 23 can be adjusted concentrically to the drum 4. Slide rails 18 can be arranged on the flexible bend 23, along which the pins 20a of the flat bars 20 slide. Various structural embodiments of the slide rails 18 exist, but these are not relevant to the invention.

[0031] The radius of the flexible arch 23 and the sliding bar 18 arranged thereon is set concentrically to the radius of the drum 4, since the flat bars 20 are guided against the direction of rotation of the drum 4 on their flat travel and should always maintain a constant distance from the drum 4 (carding gap). The flat bars 20 slide on the upper side of the sliding bar 18 with their sliding elements or pins 20a, which are guided and moved at a distance from one another via a belt 24. There are various technical solutions for determining the carding gap, one of which is the calibration of the carding gap by means of an electrical short circuit. For example, the sliding elements or pins 20a can interact with a contact element 22, which can be arranged, for example, laterally on the sliding bar 18 or on the flexible arch 23. Alternatively, an electrically conductive connection between the flat bar 20 and the contact element 22 is also possible.The electrical contact during calibration is thus made via the tips of the fittings of the flat bar 20, via an electrically conductive foundation of the flat bar 20 to the sliding elements or pins 20a, which are electrically connected to the foundation, to the contact element 22.

[0032] Independently of this technical solution for carding gap calibration, the invention provides a hold-down device 25 in the area where the flat bar 20 transitions from the slide bar 18 around the deflection pulley 21, with which the carding gap can be maintained even in the beginning and end areas of the main carding zone. Depending on its position on the slide bar 18, the flat bar 20 has a tendency to tilt due to its center of gravity. This is prevented over large areas of the main carding zone by the belt 24, which presses the flat bar 20 onto the slide bar 18. As the flat bar 20 travels along the slide bar 18 after and before the deflection pulleys 21, the belt 24 can no longer exert the necessary force, so that the flat bar 20 leaves the curved guide area of ​​the slide bar 18. This increases the carding gap at this point, and effective carding is no longer guaranteed.The embodiment of Figure 2 shows the arrangement of the hold-down device 25. In this illustration, the belt 24 runs behind the hold-down device 25, and the hold-down device 25, with its concave underside 25b, is designed to guide the pins 20a of the flat bar 20 to the end of the slide bar 18 and to press them onto the slide bar so that the previously set carding gap is maintained. The hold-down device 25 can be arranged in a fixed position on the side plate 16, on the flexible bend 23, or on an adjusting flange of the card and is designed to compensate for a change in the carding gap. Alternatively, the hold-down device 25 can also be at least partially or completely fastened to one or two contact elements 22.

[0033] For this purpose, according to Figures 3a and 3b, the hold-down device 25 is designed with its concave underside 25b to compensate for a change in the distance between the flat bar 20 and the drum 4. The hold-down device 25 is structured as a shell, with a support element 26 forming the basic structure, from which the upper side 25a and two end faces 25c, 25d extend orthogonally. The support element 26, together with the upper side 25a and the two opposite end faces 25c, 25d, thus form an open shell. The missing open side of the shell is formed by a underside 25b, which is fastened to the hold-down device by means of at least one spring element 28. The at least one spring element 28 is arranged within the open shell of the hold-down device 25 and can be supported from the inside on the upper side 25a of the hold-down device 25.The at least one spring element 28 can also be supported on the inside of the support element 26, on which, for example, ribs or webs are arranged for fastening or supporting the spring elements 28 or a spring leg. The resiliently arranged underside 25b of the hold-down device 25 is designed to compensate for a change in the carding gap via the spring travel of the at least one spring element 28. In other words, the hold-down device 25 with its resilient underside 25b is designed to compensate for a change in the distance between the flat bar 20 and the drum 4. The hold-down device 25 is fixedly attached to the card. The resiliently arranged underside 25b of the hold-down device 25 presses the pins 20a of the flat bar against the slide bar 18, regardless of the size of the carding gap.The hold-down device 25 can be made in one piece with the support element 26, the upper side 25a, and the two end faces 25c, 25d from a high-strength plastic that is electrically insulating. The spring-loaded underside 25b of the hold-down device 25 can be made of a different material than the support element 26 and can be designed to be particularly flexible and wear-resistant. In the event of wear, the underside 25b can be easily replaced.

[0034] The at least one spring element 28 can be formed in one piece or consist of several resilient plastic elements arranged within the hold-down device 25. However, the at least one spring element 28 can also consist of several spring elements 28a-28g arranged within the hold-down device 25 and supported directly or indirectly on the support element 26 or from the inside on the upper side 25a. In this exemplary embodiment, the spring elements 28a-28g are designed as leaf springs, for example made of spring steel. The spring force of the spring elements 28a-28g can be increased from the center of the hold-down device 25 to an end face 25c, since this is where the greatest contact pressure on the pins 20a of the flat bars 20 is necessary to maintain the specified carding gap.This can also be seen in Figure 2, where the end face 25c is arranged in the deflection area of ​​the flat bars 20 from the slide bar 18 to the deflection roller 21, where the greatest compressive force is required. 29a and 29b denote fastening elements in the form of a tab or bore for fastening the hold-down device 25 to the side plate 23 or adjusting flange of the card and / or to the contact element 22. The hold-down device 25 is thus constructed asymmetrically, so that the increasing spring force is only necessary on one end face 25c of the hold-down device 25. Therefore, two pairs of mirror-symmetric hold-down devices 25 are required for the card. With a symmetrical design of the hold-down device 25, four identical hold-down devices 25 can be used for both sides of the card, whereby the increasing spring force in the area of ​​one end face 25c is possible by exchanging or adjusting a pressure element.The support element 26 is aligned with one side toward the side surface of the carding machine, so that the open shell is aligned toward the drum 4. Openings in the support element 26, not further designated, serve to clean the components and parts arranged in the open shell of fibers using compressed air.

[0035] The underside 25b can be connected to the hold-down device 25 via the at least one spring element 28, for example, by means of a clip connection. Alternatively, an articulated and flexible connection between the underside 25b and the support element 26 or the upper side 25a is also possible, with the spring elements 28 transmitting the contact pressure between the underside 25b and the support element 26 or the upper side 25a. Stops (not shown) limit the spring travel, preventing complete rebound.

[0036] The hold-down device 25 according to the invention is used twice on the card (see Figure 1) on each side of the drum 4, i.e. in the flat circuit after the left large deflection roller 21 and before the right large deflection roller 21.

[0037] The invention is not limited in its implementation to the preferred embodiment described above. Rather, a number of variants are conceivable, which utilize the presented solution even in fundamentally different embodiments. All features and / or advantages apparent from the claims, the description, or the drawings, including structural details or spatial arrangements, may be essential to the invention both individually and in a wide variety of combinations.

[0038] Reference symbol

[0039] 100 carding

[0040] 1 feed roller

[0041] 2 dining tables

[0042] 3a, 3b, 3c licker-ahead

[0043] 4 drums

[0044] 5 customers

[0045] 6 scraper roller

[0046] 7 Squeeze roller

[0047] 8 Squeeze roller

[0048] 9 Fleece guide element

[0049] 10 funnels

[0050] 11 Take-off roller

[0051] 12 Take-off roller

[0052] 13 Carding element

[0053] 15 cans

[0054] 16 Side plate

[0055] 17 revolving lids

[0056] 18 Slide bar

[0057] 19 Adjusting spindle

[0058] 20 flat bar

[0059] 20a pin

[0060] 21 pulley

[0061] 22 Contact element

[0062] 23 flexible arches

[0063] 24 belts

[0064] 25 hold-down clamps

[0065] 25a top

[0066] 25b bottom

[0067] 25c, 25d front side

[0068] 26 supporting element

[0069] 27 elastic sliding element

[0070] 28a-g spring element

[0071] 29a, b Fastening element

Claims

Patent claims 1. A carding machine (100) comprising a drum (4) and a revolving flat (17) with flat bars (20) revolving around a partial area of ​​the circumference of the drum (4), wherein the flat bars (20) are guided at a distance from one another on both sides by means of belts (24) and are moved with their sliding elements or pins (20a) along a sliding bar (18), wherein the belts (24) are guided around at least two deflection rollers (21), and that in the region of the transition of the flat bars (20) from the sliding bar (18) around the deflection roller (21) or in the region of the transition from the deflection roller (21) to the sliding bar (18), a holding-down device (25) is arranged in a stationary manner, which is designed to press the flat bars (20) onto the sliding bar (18), characterized in that the holding-down device is designed to change the carding gap between the clothing of the drum (4) and the clothing of the flat bars (20). compensate.

2. Card according to claim 1, characterized in that the hold-down device (25) has a support element (26) with an upper side (25a), two end faces (25c, 25d) and a lower side (25b), wherein the lower side (25b) is concave and acts with a compressive force on the sliding elements or pins (20a) of the flat bars (20).

3. Card according to claim 2, characterized in that the pressure force is generated by means of at least one spring element (28).

4. Card according to claim 2, characterized in that the underside (25b) of the hold-down device (25) varies in distance from the upper side (25a).

5. Card according to one of the preceding claims, characterized in that the underside (25b) of the hold-down device (25) is fastened to the support element (26) or to the upper side (25a) of the hold-down device (25) by means of the at least one spring element (28).

6. Card according to claim 3, characterized in that the at least one spring element (28) consists of an elastic plastic or of several spring elements (28a-28n) which are designed as a compression spring, leaf spring or disc spring.

7. Card according to claim 3, characterized in that the at least one spring element (28) has an increasing spring force from the center of the hold-down device (25) to an end face (25c) which is in the region of the transition of the flat bars (20) from the slide bar (18) around the deflection roller (21) or in the region of the transition from the deflection roller (21) to the slide bar (18).

8. Card according to claim 1, characterized in that the hold-down device (25) with the support element (26) of the upper side (25a) and the two end faces (25c, 25d) is designed as an open one-piece or one-piece shell.

9. Card according to claim 8, characterized in that the missing open side of the shell is formed by the underside (25b).

10. Card according to claim 8, characterized in that the at least one spring element (28) is arranged in the open shell of the hold-down device (25).

11. Card according to one of the preceding claims, characterized in that the hold-down device (25) is fastened by means of fastening elements (29a, 29b) to a side plate (16), to a flexible bend (23), to an adjusting flange or to at least one contact element (22) of the card (100).

12. A hold-down device (25) for use on a carding machine (100), designed to compensate for a carding gap change between the clothing of the drum (4) and the clothing of the flat bars (20), having the features of one of claims 2 to 11.

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