GB2109831A

GB2109831A - Pin for textile machines and apparatus and method for its production

Info

Publication number: GB2109831A
Application number: GB08232726A
Authority: GB
Inventors: Josef Egerer
Original assignee: Staedtler and Uhl KG
Current assignee: Staedtler and Uhl KG
Priority date: 1981-11-20
Filing date: 1982-11-16
Publication date: 1983-06-08
Also published as: DE3146006A1; DD207008A5; FR2516946A1; JPS58144130A; IT8224270A0

Abstract

A pin has the shape of a lozenge with rounded corners or of an ellipse in cross-section in the working region. Such a pin is produced by a stamp and stamp support which has a gable- roof-like recess, the cable axes being parallel to one another. Wire is supplied to such a stamping press while being unrolled from a supply spool, there a shaping stamping is carried out and the resulting excess is punched off by a device disposed immediately afterwards. Pins so produced can be closely spaced and offer low-combing resistance while retaining high bending strength. <IMAGE>

Description

SPECIFICATION Pin for textile machines and apparatus and method for its production This invention relates to a pin for textile machines, such as combing, gill, hackling, carding and fibrillating machines. for example.

Its object is to provide a pin which better satisfies the fundamental requirements for the pinning of textile machines, and in particular to be able to accommodate a large number of pins per unit of length perpendicular to the combing direction and to keep as low as possible the combing resistance as a result of the friction which occurs, whiist enabling the pins to have the greatest possible resistance to bending in the main stressing directions.

Known pins only satisfy the above competing requirements inadequately. Thus pins which are round in cross-section admittedly have a comparatively high bending resistance in all directions of stress and pass without too great a resistance through the material to be processed, but with these pins the required high pin density is not achieved. On the other hand, pins are known which are substantially rectangular in cross-section and which are obtained by stamping round pins with stamps having straight stamping surfaces parallel to one another.These pins admittedly have the advantage that because of their relatively small dimensions transversely to the combing direction they can be set densely, and that they are very bending resistant in the combing direction, but on the other hand they suffer from the disadvantage that considerable frictional resistances occur during the passage of compressed material between the parallel lateral surfaces of adjacent pins and the pins are easily bent in the direction transverse to the combing direction.

In order to provide a pin which ensures a long service life with satisfactory processing quality, it is proposed, according to the invention, that the pin should have, in cross-section in the working region, the shape of a lozenge with rounded corners.

In an alternative embodiment of the invention, the pin has in cross-section in the working region, the shape of an ellipse.

As a result of each of these embodiments of the invention, the effect is achieved that on the one hand the pin has a particularly high bending resistance in the main directions of stress, namely parallel to and transversely to the combing direction, and that the combing resistance is kept very low because a funnel effect develops between adjacent pins as a result of the shaping of the pins. As a result of the small dimensions of the pins perpendicular to the combing direction in comparison with the dimensions in the combing direction, a dense packing of the pins is rendered possible and so a satisfactory processing quality is achieved.

The invention also relates to an apparatus for producing pins of the above-mentioned kind. An important reason why such pins have not yet been known hitherto, must lie in the preconceived ideal of the specialists that the production thereof would be exceptionally expensive. As a result of the apparatus proposed according to the invention, however, the effect is achieved that the pin production is scarcely any more expensive in practice than that of previously known pins..

According to the invention, an apparatus is provided for this purpose having a stamp and a stamp support which are distinguished by the fact that the stamp and stamp support each have a gable-roof-like recess, the gable axes being parallel to one another. Starting from a blank pin which is round in cross-section, after stamping by the apparatus according to the invention, a pin cross-section of basically lozenge-shape is obtained, the corners of which are rounded as a result of the initial shape of the blank pin.

However, the stamps may also be rounded in the region of the corners of the lozenges.

In another embodiment of apparatus according to the invention, the stamp and stamp support each have a semi-elliptical cross-section. As a result of such a construction of the machining tool, elliptical pins are obtained starting from pins which are round in cross-section.

Finally, the invention further relates to a method of producing a pin according to the invention. This method starts from the fact that hitherto these pins were produced exclusively by cutting. The pin points are ground at both ends of a blank cut to length from a wire and then the fully ground pins are separated from the middle piece remaining as waste. This method is exceptionally labour-intensive and consequently, and because of the high percentage of waste material, expensive.

The method of the invention consists in giving the individual pin its shape by a pressing operation wherein the raw material in the form of wire is withdrawn from a delivery spool and supplied to a die stamp which effects a shaping stamping, after which the excess material resulting from the stamping is punched off the pin by a device disposed immediately afterwards. In this manner, the pins can be produced considerably better and above all more cheaply in a simple operation which can in practice be carried out in a single tool.

In contrast to conventional methods of production as a result of the method of the invention it is no longer necessary first to cut off pieces corresponding to the pin length from the wire supply, to dress them and then to supply these individually to a shaping process, but the individual operations are effected in a direct and continuous succession.

A process wherein, during the punching off of the excess material, the stamped pin is separated from the roll, has proved particularly advantageous. By saving the separate step of parting off, the method according to the invention becomes particularly economical.

If desired, the pins may be treated chemically or electrochemically after stamping, to provide the final shape or surface structure.

Further features, advantages and details of the invention are apparent from the following description of a preferred embodiment and with reference to the drawing, wherein Figures 1 a and 1 b show a side view and a cross-section.through a strip of pins equipped with pins which are round in cross-section; Figure 2a and 2b show illustrations corresponding to Figure 1 of a strip of pins equipped with pins which are substantially rectangular in cross-section; Figures 3a and 3b show enlarged illustrations corresponding to Figure 1b and Figure 2b; Figure 2c shows an illustration corresponding to Figures 3a and 3b of two adjacent pins according to the invention which are made substantially lozenge-shaped in cross-section, and Figures 4 and 5 show further cross-sectional shapes provided according to the invention.

In Figures 1 and 2, the conditions are illustrated, for example, during combing with strips of pins 1 and 2 which are equipped with pins 3 and 4 which are round or substantially rectangular in cross-section. In both cases, the combing quality depends on the density of packing of the pins, that is to say on the number of pins per length of pin strip x. The free area of passage A between two adjacent pins, which is illustrated hatched in each case, offers a corresponding criterion. A comparison of Figures 1 and 2 shows that with pins 4 which are substantially rectangular in cross-section, with the same area A, a greater pin density is achieved because of the smaller diameter perpendicular to the combing direction, in that there eight pins can be disposed on a section of pin strip x while only seven can be accommodated on the same section x when using round pins.

Figure 3 shows that with pins 5 which are substantially lozenge-shaped in cross-section, according to the invention (see Figure 3c), the same pinning density can be achieved as with pins 4 which are substantially rectangular in cross-section, but the mechanical characteristics are considerabiy more favourable. This results from the fact that the lateral faces 6 of adjacent pins 5, situated at the front in the direction of combing K form a kind of funnel so that compressed material in the fleece to be processed can pass with less friction in comparison with the situation in Figure 3b. Because of their extent in the direction of the first main stressing direction 7, parallel to the combing direction K, the pins 5 there are extremely bending resistant. On the other hand, during the passage through the fleece the pins are not bent perpendicular to the direction 7, in the direction 8 either, because the components of force acting in this direction 8 are not intercepted at the lateral faces 6 and 9 by walls orthogonal thereto.

In Figure 4, a more compact embodiment which is lozenge-shaped in cross-section with more rounded corners 10, 11 is illustrated. There the action of the transverse forces F is also illustrated. q Finally, Figure 5 shows an embodiment of a pin 1 2 according to the invention with an elliptical cross-section, for which the above remarks apply in full in a similar manner.

Claims

1. A pin for incorporation in a textile machine, said pin having, in cross-section in the working region, the shape of a lozenge with rounded corners.

2. A pin for incorporation in a textile machine said pin having, in cross-section in the working region, the shape of an ellipse.

3. A pin for incorporation in a textile machine, substantially as described herein with reference to any one of Figures 3-5 of the accompanying drawings.

4. An apparatus for producing a pin as claimed in Claim 1, comprising a stamp and a stamp support, the stamp and stamp support each having a gable-roof-like recess, and the gable axes being parallel to one another.

5. An apparatus for producing a pin as claimed in Claim 2, comprising a stamp and a stamp support, the stamp and stamp support each having a recess which is semi-elliptical in crosssection.

6. A method of producing a pin as claimed in Claim 1 or 2, using a raw material in the form of wire, wherein the raw material is supplied to a die stamp, while being unrolled from a delivery spool, and is stamped to shape by said die stamp, and the resulting excess material is punched off by a device disposed immediately afterwards.

7. A method as claimed in Claim 6, wherein the stamped pin is separated from the spool during the step of punching off of the excess material.

8. A method as claimed in Claim 6 or 7, wherein, after the stamping, the pins are treated chemically or electrochemically to provide the final shape or surface structure.