Textiles: fiber preparation – Working – Carding
Reexamination Certificate
1998-12-04
2001-03-06
Calvert, John J. (Department: 3741)
Textiles: fiber preparation
Working
Carding
C076S112000, C083S846000
Reexamination Certificate
active
06195843
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a saw-toothed wire with a foot portion and a plurality of teeth arranged in linear sequence along the wire, each tooth issuing from the foot portion and ending in a single point; a process and apparatus for the manufacture of saw-toothed wires of this kind; and the use of saw-toothed wires of this kind for the processing of textile fibers.
All-steel card clothings made of a plurality of saw-toothed wires of the kind described above that are mounted parallel to each other on a carrier base have almost totally replaced the originally used needle-toothed card clothings in the processing of textile fibers. One reason for this is that all-steel card clothings of this kind are more wear-resistant and, as a consequence, offer the possibility of increasing the processing speed; another reason is the fact that saw-toothed wires of this kind are comparatively simple to manufacture.
2. Description of the Related Art
A state-of-the-art apparatus for manufacturing saw-toothed wires of the kind described at the beginning is shown in FIG.
4
. This apparatus has a feed mechanism
410
mounted on a machine bed
400
, by which a profile wire
450
is advanced along a given travel path
454
. For this purpose, the profile wire
450
is clamped tight between two feed rollers
418
, one of which is driven to turn about a rotational axis
420
that is perpendicular to the given travel path
454
.
For working the profile wire
450
, there is further a machine tool
430
mounted on the machine bed. This machine tool
430
comprises a spindle
436
running in bearings in a spindle stock
434
and driven by a 3-phase AC motor
432
to rotate in the direction shown by the arrow
437
. A blanking tool holder
438
is mounted on the front end of the spindle
436
in a rotationally fixed connection. A blanking tool
440
that is mounted on the blanking tool holder
438
and works together with a blanking die
442
of the machine tool
430
provides the means for producing saw-teeth by blanking material-free portions out of the profile wire
450
. The 3-phase AC motor
432
, the spindle stock
434
, the spindle
436
and the blanking die
442
are mounted together on a base plate
444
which can be swiveled in increments of 5° relative to the machine bed
400
and the feed mechanism
410
, as indicated by the graduation marks of the angular scale
446
.
Mounted at the front end of the spindle
436
is a bevel gear
412
. This bevel gear
412
meshes with a bevel gear
414
that is attached in a rotationally fixed connection to that end of a worm gear that faces the machine tool. Thereby, the worm gear is made to turn about a rotational axis whose position is fixed in relation to the machine bed
400
and the feed mechanism
410
. This rotation is transferred to a gear that meshes with the worm gear
416
and turns about the rotational axis
420
extending perpendicular to the given travel path
454
. This allows the pair of feed rollers
418
to be driven by the 3-phase AC motor
432
via the worm gear
416
, the bevel gear
414
, the bevel gear
412
and spindle
436
. This drive mechanism assures that the profile wire
450
is advanced each time by an equal feed interval in the direction indicated by arrow
452
between the individual work steps performed by the blanking tool
440
.
Accordingly, the apparatus shown in
FIG. 4
, using only one drive motor and one machine tool, provides a particularly simple means of producing saw-toothed wires with a constant pitch, i.e., a constant interval between the points of consecutive teeth. The shape and pitch of the teeth of the saw-toothed wire produced in this manner depend on the position of the base plate
444
relative to the machine bed
400
and also on the feed mechanism
410
, the blanking tool being used, and the transmission ratio effectuated by the worm gear
416
in combination with the gear that turns about the rotating axis
420
.
When saw-toothed wires made with equipment of the kind shown in
FIG. 4
are used in the processing of textile fibers, one observes, particularly at high processing speeds, an increase in damaged staple fibers and accumulations of non-aligned fibers, especially of short fibers (pilling effect).
SUMMARY OF THE INVENTION
In view of the problems with the existing state of the art, the object of the present invention is to provide a saw-toothed wire of the kind described at the beginning that enables a reliable and gentle processing of fibers while assuring a high degree of wear resistance combined with easy manufacturability, and to further provide an apparatus for the manufacture of saw-toothed wires of this kind.
In accordance with the invention, the problem is solved through saw-toothed wires in which the interval between the points of two consecutive teeth is different from the interval between other consecutive teeth, and through processes and devices for the manufacture of saw-toothed wires of this kind.
This solution of the inventive problem is founded on the insight that the observed damage of the staple fibers and other defects in the processing of fibers are traceable to the different requirements that a saw-toothed wire used in the processing of textile fibers must meet when penetrating into the fiber fleece, working the fiber fleece and leaving the fiber fleece. With the inventive saw-toothed wire, the tooth pitches of individual segments can be adapted to these different requirements, whereby an overall improvement of the processing result is achieved.
In this, it has proven to be particularly practical if the spacing between the points of consecutive teeth along a wire segment of given length changes continuously. To meet this condition, the spacing between the points of consecutive teeth may at first increase continuously, starting from a first given interval up to a second given interval, and then decrease continuously, starting from the second given interval back to the first given interval. From a manufacturing point of view, it has proven to be particularly advantageous if the amount of the difference between consecutive intervals between the points of consecutive teeth along a given wire segment is approximately constant.
The desired variation pattern of the pitch of saw-toothed wires according to the invention may be obtained, e.g., by forming material-free portions between the saw-teeth, the saw-teeth being of identical shape, e.g., of a triangular point shape, an arcuate tooth shape, or a truncated triangular point shape. To accomplish this purpose, it is envisaged, for example, to create material-free portions between two consecutive teeth through a number of consecutively performed operations with a machine tool, particularly a blanking tool. As an alternative, however, the saw-toothed wire may also comprise saw-teeth of differing shapes, e.g. of a rhomboid shape, that are separated from each other by material-free portions of identical shape. For the manufacture of saw-toothed wires of this kind, each of the material-free portions can be produced in a single operation.
For the manufacture of saw-toothed wires according to the invention, it has proven to be particularly practical if a relative motion of the profile wire in relation to a machine tool device is generated by means of a feed mechanism, and the profile wire, in the course of the relative motion, is subjected to successively performed operations, e.g., blanking operations, for producing the saw-teeth, wherein the feed mechanism is controlled in accordance with a given program for generating different amounts of feed travel between the successively performed operations.
In view of the generally expensive construction of the machine tool device, it is particularly advantageous if the profile wire is advanced by the feed mechanism along a given travel path and the individual operations by the machine tool device occur at a given location along the travel path.
In this, the attainment of the desired pitch variation pattern can be assured by registering the op
Calvert John J.
Darby & Darby
Graf & CIE AG
Welch Gary L.
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