Method Of Making A Loom Reed

Abstract

The dents of a reed have ends tied by wire to the backs and shaped so that one of the two parallel faces is convex, the other concave. The dent ends are assembled under resilient, compressive stress to compensate for dimensional inaccuracy in the dents and the binding wire.

Description

The present invention relates to reeds for looms. Known loom reeds have reed dents cut form flat steel strip. The cross section of the dents is therefore that of an elongated rectangle. For particular purposes use has also been made of dents with a rhombic cross section. The attachment of the dents to the longitudinal rails or rods of the reed is carried out by binding with wire of round cross section which is passed between the reed dents and around the longitudinal rods of the reed. On known reed binding machines the reed dents and the binding wires are pressed tightly up against one another during the course of binding in order to ensure a firm attachment of the reed dents in the reed and to provide the necessary number of gaps between the dents and the required breadth in order to meet the requirements of the fabric to be woven.

Since the warp ends pass through the gaps between the dents the reed must be produced with a high degree of precision in order to ensure that the warp ends have an even spacing and that the necessary number of warp ends are present in a given unit of width of the cloth produced.

Further, using known technical means it has proved difficult to ensure that there is in fact an even pitch of the reed dents and also to ensure that there is a given number of dents for a particular part of the length of the reed. Inaccuracies are to be attributed to unavoidable tolerances both in the reed dents and in the binding wire. These inaccuracies are accumulated along the length of the reed. Thus in the case of a reed with 3,000 dents and a length of 100 cm. a difference in the thickness of the reed dents of 0.01 mm. may add up to a deviation of 30 mm. along the whole length of the reed, even disregarding the deviations due to in the binding wire.

Since the inaccuracies in the thickness of the dents can only be detected after a certain length of reed has been produced, it is necessary, using conventional methods, to remove the binding wire and replace it by a binding wire of different diameter already wound into a helical form in order to correct the dimension of the reed. The production of reeds requires an extensive stock of binding wires having comparatively small differences in diameter. In order to be able to compensate for all inaccuracies likely to occur in the binding of reeds it is necessary to stock wires with differences of only 0.005 mm. in diameter. The costs of such an extensive stocking of finely graded wires and reed dent material are very high. Furthermore a large amount of time and skill and experience are necessary in order to produce reeds with precise pitch.

One object of the invention is to avoid these disadvantages.

The present invention resides mainly in a method of making a loom reed comprising a row of dents tied by wire to backs extending in the weft direction, the dents having a cross-sectional shape, at least at their ends, which permits resilient compression of the dent ends in the weft direction. For this purpose the reed dents can be made of flat material which along its whole length or only at its ends engaged by turns of the wire is given a concave-convex cross section which is arcuate or V-shaped. The resilient assembly of the reed dents which is made possible by this construction enables the manufacture of a reed which, irrespective of unavoidable dimensional inaccuracy of its component parts, has precisely equal spacing between the dents along its whole length. Furthermore there is no looseness of the reed dents since the reed dents, which are somewhat resilient in the direction of reed length are so bound in place that they have a certain residual resilience even though they are held in a bent or deformed condition.

A further advantage of the invention resides in that it is possible to make use of reed dents and binding wire with comparatively high tolerances so that material costs are reduced.

The invention also consists in a method of making a loom reed comprising aligning dents which at least at their ends are compressible in the weft direction and compressing the dents in the weft direction. The compression of the dent ends in the weft direction can be carried out individually on each dent before a following dent is placed in position beside it.

Further advantages and features of the invention will appear from the following description of preferred embodiments referring to the accompanying drawings.

FIGS. 1 to 3 illustrate diagrammatically the accumulation of dimensional deviations in dents of a known reed.

FIG. 4 is a plan view of a reed of the invention in a reed binding machine.

FIGS. 5 and 6 are respectively a side view and a front view of what is shown in FIG. 4.

FIGS. 7 to 10 are cross sections through reed dents in accordance with the invention at considerable magnification.

FIG. 11 shows part of a reed with two different types of dents.

FIG. 12 is a section on the line B--B of FIG. 11.

FIG. 13 is a side view, taken in the direction of the arrow C, of what is shown in FIG. 12.

In FIG. 1 three adjacent reed dents 2 are shown diagrammatically with an interposed binding wire 3. The center-to-center spacing A of the dents and the design pitch T are identical. FIG. 2 shows in a similar diagrammatic view a dent thickness T resulting in a spacing A.sub.1 instead of the desired spacing A. Similarly if the dent thickness is T.sup.+ instead of the required thickness the spacing changes to A.sub.2. These errors accumulate with the number of dents, which may be several thousand.

FIGS. 4 to 6 show the production of reeds of the invention on a reed binding machine. The longitudinal rails or backs of the reed are formed by four rail parts 1 to 1'" of semicircular cross section which are arranged opposite each other in pairs and connected by binder dents 4. Devices not shown in the drawings hold these rail parts in the binding machine. The reed dents 2 are supplied in the form of strip steel which is cut off as required by a shearing device 6 when the free end of the strip has reached an abutment 5. Between the last reed dent fixed in position and the newly inserted reed dent, binding wires 3 and 3' are wound in a helix about the newly inserted reed dent and the semicircular rail parts. By means of pressers 7 and 7' the last reed dent 2 inserted into position is turned through 90.degree. so as to be aligned with the warp direction and pressed against the turns of wire separating it from the next dent. Subsequently the mechanism is moved a distance equal to the pitch T by a carriage similar to the tool holder on a screw-cutting lathe, while the pressers 7 and 7' are withdrawn to their initial positions.

The pitch T can be adjusted by means of change wheels in the transmission of the carriage drive.

FIGS. 7 to 9 show reed dents 2 in accordance with the invention in enlarged sections. The dent illustrated in FIG. 7 has a slight curvature in its central portion extending almost to the edges of its parallel faces. The reed dent in accordance with FIG. 8 is slightly curved across its whole width while the reed dent in accordance with FIG. 9 has a V-section. FIG. 10 also shows a reed dent with a having a V-shaped cross section. As indicated by the lateral construction lines its overall thickness H in the weft direction is sufficient to take up the variations in the thickness of the reed material and in the diameter of the binding wire, while also allowing for a safety adjustment factor, that is to say the width H is greater than the sum of deviations in the thickness of the dent strip and in the wire diameter from design values. When such reed dents are used in the binding machine in accordance with FIG. 4 with the pressers 7 and 7', the planes defined by the lateral edges 2' and 2" and the central portion of the reed dent may be displaced resiliently relative to each other and thus compensate for dimensional errors in the reed dent thickness and in the diameter of the binding wire. If the reed dents and the binding wire are undersized, the resilient deformation of the reed dents in the binding zone will be smaller than with oversized or precisely dimensioned reed dents and binding wires or no tolerance. The final positions assumed by the reed dents in the reed under the tension of the wires 3, 3' are therefore precisely in accordance with the pitch T set on the binding machine and the corresponding final positions of the pressers 7 and 7' are always the same.

FIG. 11 shows a section of a reed with tied-in reed dents 2 which are of concave-convex cross-sectional configuration only adjacent the rail parts. The length of the bent dent ends can vary, as is indicated in FIG. 11 at x, y, and z respectively.

FIG. 12 shows that only the first four reed dents starting from the binder reed 4 are curved along the entire width of the rail parts while the more remote dents of arcuate cross section over a somewhat shorter distance.

Claims

I claim:

1. A method of making a reed which comprises:

a. positioning two elongated back members in transversely spaced, substantially parallel relationship;

b. positioning a plurality of elongated dent members having resilient end portions transversely of the direction of elongation of said back members in such a manner that said end portions of each dent member are respectively adjacent said back members;

c. winding an elongated binding material in a plurality of turns about each back member and the adjacent end portions of said dent member and thereby securing said end portions to the adjacent back member, each turn being interposed between the end portions of two successive dent members;

d. compressing the end portions of each dent member and the associated interposed turn in said direction until said end portions are resiliently deformed and the dent member is in a desired position on said back members; and

e. tensioning said elongated binding material about the end portions of each dent member to hold the same in the resiliently deformed condition, thereby securing said dent member in said desired position.

2. A method as set forth in claim 1, wherein said end portions are deformed sequentially, each turn of said binding material being wound and each end portion being deformed before the next turn is wound and the next end portion is deformed.

3. A method as set forth in claim 1, wherein said dent members are of strip material, each end portion has two opposite faces separated by the thickness of said strip material and bounded by longitudinal edges of said dent member, said edges defining a plane, the central portion of one of said faces being offset from said plane in a transverse direction, said central portion being moved toward said plane during said compressing.