Textiles: weaving – Weft manipulation – Lays or beat-ups
Reexamination Certificate
2001-05-02
2002-07-16
Falik, Andy (Department: 3765)
Textiles: weaving
Weft manipulation
Lays or beat-ups
C139S025000
Reexamination Certificate
active
06418972
ABSTRACT:
PRIORITY CLAIM
This application is based on and claims the priority under 35 U.S.C. §119 of German Patent Application 100 21 520.3, filed on May 3, 2000, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a direct drive of a reed in a loom for performing the back and forth beat-up motion. The reed to be driven is mounted on a reed slay which in turn is oscillatable back and forth about a rotational longitudinal axis of a reed support shaft.
BACKGROUND INFORMATION
There are two types of reed drive. The first reed drive type derives power from the main loom drive. The second reed drive type has its own power source. When the reed driving power is derived from the main loom drive, suitable drive transmission components are required, particularly gear drives that connect the reed support shaft to the main loom drive shaft. In such drives the reed is mounted to the reed support shaft by at least one reed slay. The drive transmission between the main loom drive shaft and the reed support shaft constitutes a rigid coupling. Such rigid coupling in looms which otherwise are representing the most recent state of the art, forms a bottleneck, so to speak, in certain respects because a rigid coupling is not amenable to a rapid, inexpensive change of the tilting angle or angle range of the reed slay and the reed. A rather costly and time consuming effort and expense is necessary when such change in the angle of the beat-up motion is required, for example when changing the loom from weaving smooth fabric to weaving terry cloth and vice versa.
European Patent Publication EP 0,892,100 A1 discloses an apparatus that is capable of changing the angle range of the beat-up motion. However, the extra effort and expense is substantial. The drive of the slay is derived from the main drive of the loom. The slay is mounted for a tiltable oscillating back and forth movement for performing the basic beat-up motion. The main loom drive supplies the power that is transmitted through a transmission (
5
) to the slay for the basic oscillating motion about a tilting axis. The reed position is adjustable, e.g. the beat-up position is adjustable by a separate servomotor
11
. Such adjustment of the beat-up position is desirable, for example for the production of terry cloth. The separate servo-motor (
11
) and its worm gear transmission (
12
,
13
) constitute an extra effort and expense even if the angular oscillating motion of the reed is derived from the main loom drive.
The second type of reed drive for the oscillating motion is disclosed in European Patent Publication EP 0,440,579 B1 which describes a reed drive that is independent of the main loom drive. The drive system for the reed comprises means for transmitting the variable r.p.m. of an electric motor onto the shaft that carries the slay which in turn carries the reed. The drive motor of this independent drive system requires a closed loop control for varying the motor r.p.m. The transmission of the drive power of the electric motor to the reed support shaft requires drive transmissions such as at least one coupling gear or an eccentric cam drive or a belt drive. All these components require a respective installation space within the loom. Moreover, drive systems of this type are rather prone to wear and tear and hence the maintenance effort and expense is substantial.
German Patent Publication 198 21 094 A1 discloses a loom with a reed that is driven by an electromagnetic linear motor that imposes a controlled back and forth oscillating motion on the reed. For this purpose the slay is connected to the linear motor by an articulated connecting rod, whereby the rod and an electromagnet forms the electromagnetic linear motor for the slay or the reed. Such a drive makes it possible to adjust the beat-up angle of the slay in any desired position independently of the main loom drive. Another advantage is seen in that the beat-up frequency can be adjusted to any particular requirement in a simple manner. However, these advantages have to be considered in the light of substantial disadvantages. The articulated connecting rod constitutes a structural element that has critical characteristics because the articulated connection of the connecting rod to the slay requires a bearing that is exposed to a substantial wear and tear. As a result, maintenance work needs to be done frequently which reduces the productivity of a loom equipped with such an external linear motor. Moreover, if the maintenance work is not performed often enough, a substantial play may develop in the articulating bearing so that the quality of the individual beat-up motions becomes different over time. Such differences in the beat-up motion are quite noticeable in the finished fabric, either in the form of insufficiently dense fabric spots or in extremely dense fabric spots amounting even to stripes in the finished fabric. Another disadvantage of the construction with an external linear motor is seen in that the linear motor must be positioned outside of the slay of the loom, thereby not only increasing space requirements, but also requiring a relatively stiff construction of the connector rod and the stationary component of the linear motor in order to achieve an oscillating motion of the slay and thus of the reed. Another limitation of the external linear motor is seen in that it has its limitations with regard to the high speed capability of modern looms with regard to their r.p.m. and with regard to the weaving width.
OBJECTS OF THE INVENTION
In view of the foregoing it is the aim of the invention to achieve the following objects singly or in combination:
to provide a rotary drive for a reed or rather for the slay that carries the reed which drive avoids the drawbacks outlined above while simultaneously accommodating the requirements of modern high speed looms without deriving its driving force from the main loom drive;
to provide a reed drive that is independent of the main loom drive while simultaneously accommodating the performance parameters of modern looms, particularly with regard to high speed r.p.m.s;
to construct the reed drive with a low mass and which shall not require additional installation space in the loom and so that the drive realizes an oscillating dynamic of the reed that is uniform throughout the weaving process from start to finish so that variations in the fabric density are avoided, particularly start-up faults in the fabric are to be avoided;
to provide a reed drive that is suitable for weaving smooth fabrics as well as terry cloth fabrics; and
to permit an adjustment of the oscillating angle and of the beat-up position of the reed to any position within the total oscillating angle of the reed.
SUMMARY OF THE INVENTION
The above objects have been achieved according to the invention in that the reed drive has a direct electromagnetic drive motor into which the reed support shaft is integrated as a motor component. The direct drive electromagnetic motor comprises a rotor and a stator. Either the stator or the rotor is formed by the reed support shaft. In a second embodiment the direct drive motor comprises electromagnetic motor elements that together with the reed support shaft form a linear motor. The linear motor elements are angularly arranged around the reed support shaft to form a circular configuration to convert linear motion components of the linear motor into oscillating reed beat-up motions oscillating back and forth between a rear position and a beat-up position.
If the reed support shaft is constructed as a stator, the shaft is mounted in a rigid position in the loom frame and an external rotor surrounds the nonrotatable shaft, whereby the external rotor carries at least one slay which in turn carries the reed.
The direct drive motor in another embodiment is constructed as an electric servomotor or as a circularly configured electromagnetic linear motor. The linear motor also comprises two embodiments, either with the reed support shaft stationary or with the reed support shaft forming the
Holz Hans-Joachim
Krumm Valentin
Loehr Heinz-Peter
Falik Andy
Fasse W. F.
Fasse W. G.
Lindauer Dornier Gesellschaft mbH
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