GB2125077A

GB2125077A - A feeler for tenter clip chains

Info

Publication number: GB2125077A
Application number: GB08318429A
Authority: GB
Inventors: Hans Cramer
Original assignee: H Krantz GmbH and Co
Current assignee: H Krantz GmbH and Co
Priority date: 1982-08-04
Filing date: 1983-07-07
Publication date: 1984-02-29
Also published as: DE3229098C2; FR2531939A1; FR2531939B1; GB2125077B; JPS5943758A; IT1164339B; IT8322300A0; DE3229098A1; GB8318429D0; IT8322300A1; ES282116U; ES282116Y

Abstract

Arranged with play in a slot of a feeler 4 is a knife 6 the cutting edge 7 of which is at all times adjusted parallel to the plane of a clip table 8. This parallel adjustment is possible because the longitudinal edge 10 of the knife 6 opposite the cutting edge 7 is convex and is supported on a correspondingly concave depth (upper) limit of the slot. A bolt 13 prevents the knife 6 from dropping out by extending through a perforation in the centre of the knife 6, the diameter of the perforation being greater than the diameter of the bolt 13 so that parallel adjustment of the knife 6 is not hindered. <IMAGE>

Description

SPECIFICATION A feeler for tenter clip chains This invention relates to a feeler for tenter clip chains of stretching and drying or fixing machines.

Such feelers, mounted swingably on the clip body, are predominantly produced from light metal such as aluminium or aluminium alloy, whilst knives which are held in the feelers and serving for grasping and clamping a goods web on a so-called clip table are generally made of stainless steel.

In the case of known feelers, the knife is anchored securely in the feeler by the knife being cast integrally therein during casting of the feeler.

The cutting edge of the knife has to be ground so that, after anchorage of the knife in the feeler, uniform grasping and holding of the edge of the goods web is ensured over the entire knife length.

This is usually achieved by grinding the cutting edge of the knife so that it is parallel with the clip table plane. However, it has become apparent that the knife cutting edge does not remain parallel to the clip table when the clip is subject to heat, e.g. when running through drying or hotfixing sections of a machine, although the edge returns to such parallel alignment in the cold state of the clip. As a result of the thermal expansion of the light metal of the feeler, which is considerably greater than the steel of the knife, there is a kind of bimetal effect, as a result of which the knife is so curved or buckled that its ends are bent downwards. The centre of the knife cutting edge thus no longer bears on the edge strip of the goods web to retain same.Under tension, caused by the inherent weight of the goods web, the goods web which is held merely at the ends of the knife springs in arcuately in the region between the knife ends as a result of shrinkage during fixing or drying. The edges of the goods web are thereby given a sinusoidal course such that only at a certain spacing from the edges of the goods web to the warp threads again extend rectilinearly and parallel to one another. This edge curvature is not desirable for the further processing of the web of fabric.

In order to obviate the faults resulting from the temperature differences so as to achieve a satisfactory and firm holding of the goods web in both the cold and warm state of the clip, it is known from German Patent No. 899 784 to provide at least two knives in the feeler. These knives lie side-by-side and are arranged so as to be movable parallel to the central plane of the feeler and at least one pressure compensating traverse rests on the upper edges of these knives.

The individual knives have elongate holes and are mounted movably on pins which penetrate the feeler. The knives can adjust themselves obliquely and come to bear on the edge strip at one side of the goods web with the one or other knife end.

Furthermore, a feeler for tenter clip chains in which the knife is subdivided into individual discs is known from German Patent No. 425 848. In this type of knife each individual disc is supposed to be able to superimpose itself automatically on the edge strip of the goods web. The individual knife discs are also held movably in the feeler lever by virtue of elongate holes which engage into pins on the feeler lever. This movable arrangement of the knife discs in the respective levers can lead to the fact that not all the knife discs come uniformly to rest on the edge strip on the goods web and a knife disc drawn more severely into its respective feeler lever does not contribute to the retention of the goods web.

Finally, German Patent No. 1 460 61 5 discloses a feeler for tenter clip chains in which a knife cast into the feeler has incisions which extend as far as the lower end of the knife. After casting, grinding of the knife cutting edge causes individual knife parts to arise.

The bimetal effect can be reduced by knife parts having relatively short cutting edges.

However, secure anchorage of the knife parts in the feeler has the disadvantage that upon wear of the knife parts the feeler as a whole has to be exchanged.

An object of the invention is to equip a feeler with a knife which is simple to produce which is not subdivided, which is not subject to any bimetal effect and which, moreover, can easily be removed and replaced.

This object is achieved by providing a feeler for tenter clip chains of stretching and drying or fixing machines comprising a knife which is arranged movably in a slot of the feeler, which knife has a rectilinear cutting edge, has a perforation with a cross-section greater than the cross-section of a pin which extends therethrough, and is held in the feeler on both sides of the slot, characterised in that the perforation is disposed in the centre of the knife and the longitudinal edge of the knife opposite the rectilinear cutting edge extends, at least over a central region, in a convex arc by virtue of which the knife is supported against the depth limit of the slot which extends in a concave arc.

As a result of the design in accordance with the invention, the knife is given latitude to adjust itself in the slot in such a way that its cutting edge is, in an unimpeded manner, brought parallel with the plane of the clip table. The working of the knife is in no way impaired because the convexly-shaped longitudinal edge of the knife can slide over the concavely-shaped depth limit of the slot without the knife losing its support.

Continuous support over the entire knife length can be achieved in accordance with a development of the invention in which the convex arc of the longitudinal edge of the knife and the concave arc of the depth limit of the slot have the same radius.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side view showing a link of a tenter clip chain having a preferred embodiment of the feeler of the invention, which feeler is shown partially in cross-section; Fig. 2 is a front view of the link shown in Fig. 1 also with the feeler shown partially in crosssection: and Fig. 3 is a similar front view of the link shown in Fig. 1 in which the knife has been slightly deflected compared to Fig. 2.

A preferred embodiment of the feeler 4 in accordance with the invention is provided with a downwardly-open slot 5 in which a knife 6 is supported. The knife 6 has a rectilinear cutting edge 7 which protrudes from the slot 5 to contact a clip table 8 and restrain an edge of a goods web (not shown) thereon. A roller 9 mounted on the feeler 4 so as to be freely rotatable fixes the clamping depth.

The knife 6 has a longitudinal edge 10 lying opposite the rectilinear cutting edge 7. This edge 10 extends in a convex arc and abuts the depth limit, in this case the upper limit 11 of the slot 5 which extends in a correspondig concave arc.

So that the knife 6 has considerable play in the slot 5 yet is held securely therein, a perforation in the form of a bore 12 of circular cross-section is provided in the centre of the knife 5. A pin 13 in the form of a threaded bolt is screwed into the feeler 4 and extends through the perforation 12 of the knife 6 to prevent the knife 6 from dropping out of the slot 5.

Because the convexly-shaped longitudinal edge 10 of the knife 6 can slide over the concavely-shaped upper limit 11 of the slot 5 whilst support of the knife is maintained and because the cross-section of the bore 12 in the knife 6 is greater than the cross-section of the bolt 13, the knife 6 always adjusts ifself under loading so as to achieve an appropriate distance between its plane and the feeler 4 in such a way that the rectilinear cutting edge 7 is aligned absolutely parallel to the clip table 8.

Claims

1. A feeler for tenter clip chains of stretching and drying or fixing machines comprising a knife which is arranged movably in a slot of the feeler, which knife has a rectilinear cutting edge, has a perforation with a cross-section greater than the cross-section of a pin which extends therethrough, and is held in the feeler on both sides of the slot, characterised in that the perforation is disposed into the centre of the knife and the longitudinal edge of the knife opposite the rectilinear cutting edge extends, at least over a central region, in a convex arc by virtue of which the knife is supported against the depth limit of the slot which extends in a concave arc.

2. A feeler as claimed in claim 1, characterised in that the convex arc of the longitudinal edge of the knife and the concave arc of the depth limit of the slot have the same radius.

3. A feeler as claimed in claim 1 or 2, characterised in that the perforation has a circular

4. A feeler as claimed in claim 1, 2 or 3, characterised in that the pin is in the form of a threaded bolt.

5. A feeler as claimed in any preceding claim, characterised in that at one side of the slot the pin is tightly screwed into a threaded bore of the feeler.

6. A feeler for tenter clip chains substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.