Textiles: braiding – netting – and lace making – Apparatus – Braiding
Reexamination Certificate
1999-11-22
2001-11-20
Calvert, John J. (Department: 3765)
Textiles: braiding, netting, and lace making
Apparatus
Braiding
C087S014000, C087S015000, C087S018000, C087S020000, C087S031000, C087S033000, C087S043000, C087S049000, C087S055000, C087S056000
Reexamination Certificate
active
06318227
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circular braiding machine for braiding strands and, more particularly, to a circular braiding machine with a rotation axis, the circular braiding machine comprising a group of inner spools and another group of outer spools, each spool carrying a single strand, and each group arranged on a respective circular track coaxial to the rotation axis and movable in opposite directions and means for crossing the strands of the inner and outer spools. It also relates to a device for strand guiding in this circular braiding machine comprising a strand guide part or guide device arranged between a first spool and a braiding point for a strand fed to the braiding point from the first spool, which is movable back and forth for crossing the first strand over at least one second strand coming from a second spool so that the length of a section of the first strand between the first spool and the crossing point continuously changes, and a device for compensating these length changes having at least one movable guide element for the first strand arranged between the first spool and the guide part or guide device.
2. Prior Art
In the known circular braiding machine of this type, for example as described in German Patent Documents DE 44 22 893 A1 and DE 195 47 930 A1, the strands of material being braided coming from the outer and inner spools are guided with guide devices to the braiding point, which are movable back and forth inclined to the rotation axis in order to cause crossing of the concerned strand according to the rapid braiding principle with the strands coming from the outer and inner spools. The motion of the guide devices occurs, among other reasons, with the help of crank elements and push rods so that the guide devices or parts execute an essentially sinusoidal motion about the rotation axis of the circular braiding machine, however they accelerate in the region of the crossing point and are delayed at the turning point regions in order to avoid whip-like back and forth motions.
The motion of the guide devices or parts has the result that the length of the strand sections located between the outer spools and the braiding point continuously changes during operation. Thus a compensation device must be provided for each outer spool, which temporarily stores an excess strand portion and delivers this strand portion on demand in order to avoid sagging or tearing of the strands. A compensation device of this type usually comprises pivoting plates acted on by spring forces and rollers attached to them that must be in a position to compensate for length changes of up to about 50 mm. This has the disadvantage that somewhat expensive springs are necessary which have a constant characteristic curve over the entire compensation range. This is not always attainable and a variation of the tension within the above-described strand section occurs as a result. Furthermore this type of compensation device has a certain inertia because of the masses being moved, which can lead to tearing of the strands or the threads or filaments forming them at high rotation speed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a strand guiding device of the above-described kind for a circular braiding machine, in which the greater part of the compensation for length changes is obtained with other means than springs.
It is another object of the present invention to provide a circular braiding machine for braiding strands including this strand guiding device with the means for compensation of strand length changes according to the invention.
These objects, and others which will be made more apparent hereinafter, are attained in a strand guiding device in this circular braiding machine, this device for strand guiding comprising a guide part or guide device for a first strand arranged between a first spool and a braiding point for a strand fed to the braiding point from the first spool, which is movable back and forth for crossing the first strand over at least one second strand coming from a second spool so that the length of a section of the first strand between the first spool and the braiding point continuously changes, and a device for compensating these length changes having at least one movable guide element for the first strand arranged between the first spool and the guide part or guide device.
According to the invention the compensation device includes a positive guidance means for moving the at least one movable guide element, whereby the length changes of the first strand are at least partially compensated by the motion of the at least one movable guide element.
According to the invention the circular braiding machine has a rotation axis and comprises
a group of inner spools and another group of outer spools, each spool carrying a single strand, and each group being arranged on a respective circular track coaxial to the rotation axis and movable in opposite rotation directions;
means for crossing the strands of the inner and outer spools, wherein the means for crossing the strands includes guide parts or devices for guiding the respective strands from one groups of the spools to a point between the spools of that group and a braiding point, whereby the guide parts or devices are movable back and forth so that respective lengths of the strand sections between the braiding point and the spools of the one group continuously change; and
means for compensating for the changes in the lengths of the strand sections including at least one movable guide element for the strands arranged between each spool of the one group and the guide element associated therewith and a positive guidance means for moving the at least one movable guide element so that the length changes of the first strand are at least partially compensated by motion of the at least one movable guide element for the strands.
Preferred embodiments of the invention are claimed in the appended dependent claims.
The invention is based on the surprising understanding that it is possible to compensate for about 75 percent or more of the strand length changes due to controlled motion along a path with a positive guidance of the movable conducting members for the strands, which can be simply performed and adjusted to the individual embodiment. The remaining compensation motions performed by springs are negligibly small in regard to their inertia and danger of breaking and may be performed with springs which are provided with constant characteristic curves only over a short spring displacement range.
REFERENCES:
patent: 4535674 (1985-08-01), Bull et al.
patent: 5457967 (1995-10-01), Scherzinger
patent: 5749280 (1998-05-01), Scherzinger
patent: 5787784 (1998-08-01), Scherzinger
patent: 44 22 893 A1 (1996-01-01), None
patent: 4422893-A1 (1996-01-01), None
patent: 195 47 930 A1 (1997-06-01), None
patent: 19547930-A1 (1997-06-01), None
Calvert John J.
Hurley Shaun R
Sipra Patententwicklungs u. Beteiligungsgesellschaft mbH
Striker Michael J.
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