GB2029869A - Flats for carding machines - Google Patents

Abstract

A flat has a body which provides the clothing flange 62 and the essential reinforcing formation for that flange made as an extrusion, part of the extrusion being removed at each end to provide a flat-end 72 projecting beyond the clothing flange and its reinforcing, this flat-end being adapted for engagement with the usual bend and plain bowls of the carding machine. In the construction shown in the drawing, the extruded reinforcing comprises a hollow section, and the flat also includes a separately formed nug 76 having a spigot-and- socket connection with the extruded body and a releasable wear-sustaining component 74 which provides the bevel surface of the flat. <IMAGE>

Description

SPECIFICATION Improvements in or relating to flats for carding machines This invention is concerned with flats for use in carding machines, and more particularly with an economic method of constructing a flat which has the necessary physical characteristics.

The carding machine flat has to withstand a considerable bending load due to its weight, and due to the carding action which tends to pull the flat towards the cylinder, since the flat is a beam simply supported at its ends.

(The force due to the carding action may be a tangential pull, since the component of movement due to cylinder movement relatively to the flat will be large). In order to withstand these inherent and applied loads, the flat has to have as large a moment of inertia as possible within the limitations imposed by the machine constructions, and this has dictated the design of the flat, and to some extent, its method of manufacture.

Essentially, the conventional flat comprises a clothing flange with a machined underside to receive the card-clothing top, a rib extending along the length of the flange, to provide the necessary reinforcement of the flat against the inherent and applied loads, a flat end at each end of the flat for sliding engagement on a respective bend of the carding machine, and a nug at each end which engages in the notch wheel used to drive the flats. The precise construction of the flat varies with different carding machine manufacturers.

Conventionally, carding machine flats are made of cast iron, and the casting techniques used in the manufacture of the flats require highly skilled labour so that the manufacture of good quality flats is generaly uneconomic in countries where the necessary skills might be available. Indeed, for this reason, it is becoming increasingly difficult to obtain good quality flats. It is the principal object of the present invention to provide a method of producing a satisfactory flat at an economic price.

According to this invention, a flat for use in a carding machine has a body which provides the clothing flange and the essential reinforcing formation for that flange, the body being made as an extrusion, part of the extrusion being removed at each end to provide a flat end projecting beyond the clothing flange and its reinforcing, this flat end being adapted for engagement with the usual bend and plain bowls of the carding machine.

Preferably, at least one wear-resistant surface is provided on the flat end, this wearresistant surface having a resistance to wear greater than that of the material from which the body of the flat is made. The body preferably includes a hollow section which provides the reinforcing. It is further preferred that a separately formed nug is provided, which has a spigot-and-socket connection with a part of the extruded body. The nug may be retained in the extruded body by friction.

According to a preferred feature of the invention, a releasable wear-sustaining component is provided on the flat end, this component providing the bevel surface of the flat.

The construction of a carding machine flat in accordance with the invention, will now be described by way of example only, with reference to the accompanying drawing which is a perspective "exploded" view of one end of a flat.

The flat 60 has a body comprising the usual clothing flange 62 and the reinforcing rib 64, all of which is formed as an extrusion.

The rib 64 is in the form of an inverted channel with a tubular section 66 inside the channel. The extruded flat body is made in aluminium alloy, and both the cost of the material and the cost of the extrusion process are relatively low compared with the conventional cast iron construction. The aluminium alloy has a lower bending strength than the cast iron from which the flats are usually made, but the reduced strength is compensated for by the design of the rib 64, which of course, possesses a higher moment of inertia than the conventional slightly tapered crosssection rib. Furthermore, the extruded aluminium alloy flat is much lighter than the usual cast iron flat, so that the inherent bending stresses are reduced.

However, as extruded, the flat is of the same cross-section from end-to-end, and would not be suitable for running on the bends, nor would it have nugs. Moreover, the aluminium alloy would wear relatively rapidly, if the flat ends were simply machined out of the extrusion.

The rib 64 is milled away at each end of the flat, leaving lands 68 with a shallow groove 70-which is in the extrusion-between them. Also, the extremity of the flat is further milled to produce a flat end 72 of a shape similar to that on card-clothing flats. The underside of the flat end 72 (as seen in the drawing) has a concave shape with longitudinal edge portions 86. Also, the top surface 88 of the flat end 72 is somewhat concave.

A releaseable component 74 is provided, this component being made as a pressing in work-hardened phosphor-bronze, and having relatively thin walls. It is generally in the form of a box section having a bottom wall 90, side walls 92 and a top 94, the top consisting of two inturned flanges on the side walls, with a narrow gap 96 between them. The top and bottom walls 94 and 90 of the component 74 are shaped so that the top and bottom surfaces of the component 74 are concave in similar style to the usual bevel and back surfaces of the flat end.

The component 74 is fitted on to the machined flat end 72 by sliding it on from the end, until the flat end is almost totally embraced by the releaseable component. It is preferred that the concavity of the bottom wall 90 is rather less pronounced than that of the machined undersurface of the flat end, so that when the component 74 is fitted on the flat end, the bottom wall 90 fits closely on the machined underside of the flat end 72 along the edges 86 of the flat end, but there is a space between the centre part of the wall 90 and the centre part of the undersurface of the flat end. This ensures that the bottom wall 90 is properly located and receives support from the flat end in the edge regions 86, where wear will take place.

The component 74 is so designed that it grips on the flat end 72 by virtue of its own resilience. A work-hardened phosphor-bronze component has an inherent resilience which will permit it to distend as it is being fitted on to the flat end, and hence it will remain in position by frictional grip on the flat end until deliberately removed. Of course, the component could be made in other materials which would have the required resilience for this purpose. However, the phosphor-bronze has excellent tribology characteristics, when running on cast iron or steel, as is the case, when the component 74 is running on the bend of the carding machine. Hence, when the flat is fitted with the component 74, it will slide very smoothly on the bends of the machine, and the component can be expected to last for a considerable time, before it becomes so worn that it has to be discarded.Of course, when the component 74 becomes badly worn, it is only necessary to remove it by pulling it off the end of the flat, and to replace it by a similar component which can simply be pushed on to the end of the flat. Therefore, by the provision of the releaseable wear-sustaining component such as that illustrated at 74, the problem of flat end wear is overcome. The underside of the flat end is rebated at 98 to accommodate the bottom wall of the component 74, whilst maintaning the lower marginal edge portions of that component in the same plane as the underside of the clothing flange 62. This rebating of the flat end may not always be necessary.

A separately formed nug 76 is also provided at each end of the flat. This simply takes the form of a short cylindrical bar 78 which has a radius equal to that of the semicircular surface of the conventional nug and a spigot 80. A screw-threaded hole 82 is formed in the bar 78 to accept a setscrew of the flat chain, and the spigot 80 is a push fit into the central bore 84 of the tubular portion 66 of the flat extrusion. If necessary, this bore 84 can be machined at the end to receive the spigot, but it may be possible to extrude the bore accurately enough to avoid such machining.

Thus, the construction illustrated provides a flat comprising five elements, that is to say: the extruded body, two releaseable components and two nugs, and the assembly of the flat can be carried out entirely by pushing the releaseable components on to the flat ends and pushing the nug spigots into the ends of the bore 84.

It is to be understood that other kinds of wear-sustaining component could be fitted to the flat end, and that the component need not necessarily be releaseable. It could for instance be secured by rivets, screws or even adhesive. Moreover, the flat end could be adapted to sustain wear by methods other than the fitting of a separate wear-sustaining component. For example, the flat end could be given a wear-resistant coating, or it could be given a hardening treatment. Indeed, the flat could be extruded in a material having the required wear-resisting qualities (such as titanium for example) in which case no further adaptation is required after the flat ends have been formed on the extrusion.

Claims (6)

1. A flat for use in a carding machine having a body which provides the clothing flange and the essential reinforcing formation for that flange, the body being made as an extrusion, part of the extrusion being removed at each end to provide a flat end projecting beyond the clothing flange and its reinforcing, this flat end being adapted for engagement with the usual bend and plain bowls of the carding machine.

2. A flat as claimed in Claim 1, wherein at least one wear-resistant surface is provided on the flat end, this wear-resistant surface having a resistance to wear greater than that of the material from which the body of the flat is made.

3. A flat as claimed in Claim 1 or Claim 2, in which the body includes a hollow section providing the reinforcing.

4. A flat as claimed in any one of Claims 1 to 3, in which a separately formed nug has spigot-and-socket connection with a part of the extruded body.

5. A flat as claimed in Claim 4, in which the nug is retained in the extruded body by " friction.

6. A flat as claimed in any one of Claims 1 to 5, in which a releaseable wear-sustaining rj component is provided on the flat end, this component providing the bevel surface of the flat.