Device for cutting through pile threads on a weaving machine

Abstract

A device for cutting through pile threads on a weaving machine, including a cutting means (6), connected to a transmission body (5), and a rotatable drive means (1), which rotates alternately in the one and the other rotational direction and meshes with the transmission body (5) so that its rotation motions are converted into a back-and-forth displacement of the cutting means (6), wherein, via the transmission body (5), a pushing force is exerted on the cutting means (6). The transmission body (5) can be non-endless and interact with one rotatable drive means (1). Also, a weaving machine provided with such a cutting device.

Claims

1. Device for cutting through pile threads on a weaving machine, comprising a cutter, which is displaceable back and forth according to a substantially rectilinear motion path, a transmission body in connection with the cutter, and a rotatable drive, which is drivable so as to rotate alternately in one and another rotational direction, wherein the drive and the transmission body are provided to interact in order to convert the rotation motions of the drive, via the transmission body, into a back-and-forth displacement of the cutter, wherein the device is provided to exert by a rotary motion of the drive, via the transmission body, a pushing force on the cutter, and wherein the transmission body is flexible over at least a portion of its length.

2. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that the drive and the transmission body are provided to displace the cutter back and forth in successive motion cycles and to exert on the cutter, during each motion cycle, alternately a pushing force and a pulling force.

3. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that the transmission body is not an endless body.

4. Device for cutting through pile threads on a weaving machine according to claim 1 characterized in that the transmission body is in interaction with one single rotatable drive.

5. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that a rotation axis of the drive is practically transversely to a direction of the motion path.

6. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that the drive comprises a rotation shaft and is driven by a motor whereof the motor shaft is practically parallel to, or lies in line with, the said rotation shaft of the drive.

7. Device for cutting through pile threads on a weaving machine according to claim 6, characterized in that the rotation of the motor shaft is transmitted either directly, or via a transmission having a transmission ratio of no more than 10, to the rotation shaft of the drive.

8. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that the transmission body is elongate and comprises at least two zones extending according to the longitudinal direction and having a mutually different stiffness.

9. Device for cutting through pile threads on a weaving machine according to claim 8, characterized in that the said zones have a different stiffness, since the transmission body has in these zones a mutually different cross section.

10. Device for cutting through pile threads on a weaving machine according to claim 8, characterized in that the transmission body comprises in at least one zone a stiffener.

11. Device for cutting through pile threads on a weaving machine according to claim 10, characterized in that the stiffener is incorporated in the basic material of the transmission body and comprises one or more stiffness-enhancing layers, wherein the one or more stiffness-enhancing layers comprise one or more fibre-reinforced layers.

12. Device for cutting through pile threads on a weaving machine according to claim 10, characterized in that the stiffener is fastened externally to the basic material of the transmission body.

13. Device for cutting through pile threads on a weaving machine according to claim 8, characterized in that the transmission body comprises at the one end a head part which is connected to the cutter, and comprises at the other end a tail part, and in that the stiffness of the head part is 15 to 100 times greater than the stiffness of the tail part.

14. Device for cutting through pile threads on a weaving machine according to claim 8, characterized in that the stiffness of the transmission body decreases gradually or incrementally from a head part up to a tail part.

15. Device for cutting through pile threads on a weaving machine according to claim 8, characterized in that the stiffness of the head part lies between 1 N.m.sup.2 per metre and 500 N.m.sup.2 per metre, and in that the stiffness of the tail part lies between 0.1 N.m.sup.2 per metre and 1 N.m.sup.2 per metre.

16. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that the cutter comprises a carrier, which is connected to the transmission body, in that the carrier carries a blade, in that the cutting device comprises a cutter guide extending according to the motion path and having a carrier guide surface on which the carrier is displaceable back and forth, and in that the carrier is provided with detainer in order to detain this carrier during its displacements with respect to the guide surface.

17. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that the device comprises a guide for keeping the transmission body in interaction with the drive.

18. Device for cutting through pile threads on a weaving machine according to claim 1, characterized in that the drive comprises a number of first engagement elements, and in that the transmission body comprises a number of second engagement elements, which are provided to interact with the first engagement elements in order to convert the rotation motions of the drive, via the transmission body, into a back-and-forth displacement of the cutter.

19. Device for cutting through pile threads on a weaving machine according to claim 18, characterized in that the second engagement elements are teeth, openings or recessed zones, and in that the first engagement elements are teeth.

20. Weaving machine comprising a device for cutting through pile threads, characterized in that it is a device according to claim 1.

21. Device for cutting through pile threads on a weaving machine according to claim 15, characterized in that the stiffness of the head part lies between, and preferably between 5 N.m.sup.2 per metre and 100 N.m.sup.2 per metre, and in that the stiffness of the tail part lies between 0.15 N.m.sup.2 per metre and 0.5 N.m.sup.2 per metre.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the hereinafter following description, a drive device according to this invention is described in detail. The sole aim of this detailed description is to indicate how the invention can be realized and to illustrate the particular characteristics of the invention and, where necessary, to expound on these. This description can thus not be regarded as a limitation of the scope of this patent protection, nor of the field of application of the invention.

(2) In this description, reference is made on the basis of reference numerals to the accompanying figures, whereof

(3) FIG. 1 is a schematic representation of a portion of a weaving machine which is provided with a cutting device according to an embodiment of the invention;

(4) FIG. 2 represents a portion of the cutting device according to an embodiment of the invention in perspective view;

(5) FIG. 3 represents the blade carriage and a portion of the blade carriage guide in perspective view;

(6) FIG. 4 represents a side view of the blade carriage on the blade carriage guide according to FIG. 3;

(7) FIG. 5 represents a cross section of the blade carriage on the blade carriage guide according to the axis A-A in FIG. 3, during the cutting through of the pile threads between the two fabrics of a face-to-face fabric;

(8) FIG. 6 represents the blade carriage and a thereto connected band in interaction with the drive gear of a cutting device according to an embodiment of the invention in perspective view; and

(9) FIG. 7a represents a top view of the band portion which extends from the extremity of the head part up to the line C in FIG. 6.

(10) FIG. 7b is a schematic cross section according to the longitudinal axis F of the band portion which in FIG. 7a is located between the lines C and D.

DETAILED DESCRIPTION

(11) On a face-to-face weaving machine, two pile fabrics are woven simultaneously. For this purpose, two ground fabrics are woven one above the other, consisting of weft threads and warp threads, whilst pile warp threads are alternately bound in into the upper ground fabric and into the lower ground fabric. In this way, a face-to-face fabric having pile warp threads which extend between the upper and the lower ground fabric is obtained. In order to separate the two pile fabrics one from the other, the pile warp threads extending between the two ground fabrics have to be cut through. This is done automatically by means of a blade carried by a blade carriage.

(12) During a weaving cycle, the blade carriage is displaced over the width of the weaving machine, so that a following row of pile threads is cut through by the blade. The blade carriage forms part of a cutting device according to an embodiment of this invention.

(13) In FIG. 1, this cutting device is represented. It extends according to the lateral direction (B) of the weaving machine and is located before the weaving reed (100) on the side where the finished face-to-face fabric (101) is found.

(14) The device comprises a drive gear (1), which is fastened on the horizontal motor shaft (3) of a servo motor (4). This motor shaft (3) is perpendicular to the lateral direction (B) of the weaving machine.

(15) The drive gear (1) is provided on its rim with teeth (2), which are distributed at equal intervals over the circumference thereof. A flexible band (5) with openings (21)—see FIG. 7a—is led over half the circumference of the drive gear (1), whilst the successive teeth (2) of the drive gear (1) are found in respective successive openings (21) of the band (5).

(16) As a result, the band (5) can be transported by the rotating drive gear (1) and the rotation motions of the drive gear (1) can be converted into a displacement of the band (5). The band (5) has a head part (5a), to which a blade carriage (6) is fastened, and a tail part (5b), in which the said openings (21) are provided.

(17) A horizontal blade carriage guide (7) extends from the top of the drive gear (1), in a straight line according to the lateral direction (B) of the weaving machine, over the total cutting path which has to be covered in order to cut through all the pile threads of a row. Both the blade carriage (6) and the band (5) are displaceable according to the longitudinal direction of the blade carriage guide (7), but are detained with respect to this blade carriage guide (7).

(18) The servo motor (4) can be controlled by a control device (not represented in the figures) so as to rotate alternately in the one and the other rotational direction during the weaving process.

(19) In the blade carriage guide (7) a straight guide channel (8) is formed, in which the band (5) is displaceable. The channel has a cross section in the shape of an inverted T, wherein the opening at the top is narrower than the width of the band (5), so that this band (5) cannot leave the guide channel (8).

(20) The blade carriage (6) comprises a plate-like base part (9). In the head part (5a) of the band (5) openings (20) are provided for the fastening of the blade carriage (6) to the band (5). The fastening is realized with bolts (18), which are fitted from the bottom side of the band (5) through the openings (20) and sit with the bolt shanks in openings through the base part (9), and nuts (19), which are fitted on the bolt shanks projecting on the top side of the base part (9).

(21) The base part (9) is substantially rectangular, having two parallel first sides (9a) which extend according to the longitudinal direction (L) of the blade carriage guide (7), and two parallel second sides (9b), which extend transversely to this longitudinal direction (L). The base part (9) is provided with a blade (10) on the first side (9a), which is directed towards the face-to-face fabric (101) (see FIG. 5). The blade (10) projects past the edge of the base part (9) and has an edge in the shape of a circular arc. The blade carriage (6) is produced from a light material such as, for example, aluminium or a composite material.

(22) On the bottom side of the plate-like base part (9) two guide pieces (11) are provided, (12), which extend in parallel side by side according to the said longitudinal direction (L). Each guide piece (11), (12) comprises two wings (110), (111); (120), (121), which connect to each other forming an obtuse angle. Each guide piece (11), (12) is fastened by one of the wings (110), (120) against the horizontal bottom side of the base part (9) with a respective screw (15). The other wings (111), (121) of the guide pieces (11), (12) run obliquely towards each other in the downward direction.

(23) The obliquely converging wings (111),(121) extend along the obliquely converging flanks (7a), (7b) of the blade carriage guide (7), so that the blade carriage (6) is held on the blade carriage guide (7) during its displacements.

(24) Against those sides of the guide pieces (11), (12) which are directed towards the blade carriage guide (7) wearing parts (13), (14) are fastened.

(25) In order to keep the band (5) in interaction with the teeth (2) of the drive gear (1), four guide elements (16) are provided along the length of the path over half the circumference of the drive gear (1). The contact with the moving band (5) causes a build-up of heat. In order to avoid a situation in which the guide elements (16) become too hot, these are provided with cooling fins (16a), whether or not in combination with openings and/or channels which facilitate a cooling air circulation.

(26) In the region of the bottom rim of the drive gear (1) a horizontal band guide (17) is provided, which extends in a straight line according to the lateral direction (B) of the weaving machine. In this band guide (17) a tunnel is formed, in which the band (5) can be displaced back and forth. When the blade carriage (6), in the embodiment of FIG. 2, is in its extreme left position, a relatively long length of the band (5) will be found in the blade carriage guide (7), so that the portion which is located outside of the cutting path past the drive gear (1) will be relatively short. As the blade carriage (6) shifts more to the right, the length of this portion will increase. The band guide (17) is required to guide that portion of the band (5) which is found at the bottom past the drive gear (1).

(27) In FIG. 7a a top view is represented of that portion of the band (5) which extends from the extremity to which the blade carriage (6) is fastened (on the right in FIG. 7a) up to the line C which is indicated in FIG. 6. FIG. 7b is a schematic cross section according to the longitudinal direction (according to the axis F-F) of that portion of the band (5) which is found in FIG. 7a between the lines C and D.

(28) The band (5) is constructed as an elongate strip having a substantially rectangular cross section whereof the width is greater than the height. The head part (5a) of the band (5) is provided with openings (20) for the bolts with which the blade carriage (6) is fastened to the band (5).

(29) In the band (5), a series of openings (21) are also provided, at equal intervals, in which the teeth (2) of the drive gear (1) can be located. This row of openings (21) is located substantially in the tail part (5b) of the band (5) and runs through past the boundary line (f) between tail part (5b) and head part (5a) and ends with five openings (21) located in the head part (5a). The openings (21) in the head part (5a) are located in a transition zone (Z), where the band (5), to the right, is gradually less in interaction with the teeth (2) of the drive gear (1) and is also less bent over in order to follow the gearwheel periphery.

(30) The tail part (5b) of the band (5) is composed (see FIG. 7b) of a number of layers (30) of polyester of practically equal thickness (for example 0.1 mm). The tail part (5b) is the part having the least stiffness.

(31) In the head part (5a), the stiffness becomes incrementally greater to the right from the boundary line (f) between head part (5a) and tail part (5b) (see FIG. 7b). This stepwise increase in stiffness is obtained by, in the region of three successive lines (f), (g), (h), terminating a number of polyester layers (30) and replacing them by carbon fibre-reinforced layers (31), which connect to the terminating polyester layers and from there, at the same level in the band (5), run further to the right up to the extremity of the band (5). The carbon fibre-reinforced layers (31) have a thickness which is approximately double the thickness of the polyester layers (30). There is always one carbon fibre-reinforced layer (31) where there were, to the left of the line (f), (g), (h), two polyester layers (30) lying one upon the other (these are hereinafter referred to as ‘pairs of polyester layers’).

(32) From the leftmost line (f), a centrally situated pair of polyester layers (30) is replaced by one centrally situated carbon fibre-reinforced layer (31). From the following line (g), two more pairs of polyester layers (30) are replaced by a respective carbon fibre-reinforced layer (31). These are located respectively above and below the centrally situated carbon fibre-reinforced layer (31). From the third line (h), finally two more pairs of polyester layers (30) are replaced by a respective carbon fibre-reinforced layer (31). These layers (31) are located still further from the central layer (31) and are respectively situated on the top side and the bottom side of the band (5). The zone between line (f) and line (h), where the stiffness of the band (5) increases incrementally towards the extremity of the head part (5a), can be made to coincide with the transition zone (Z) which is indicated in FIG. 7a.

(33) On the bottom side of the band (5), over the total length thereof, a Teflon layer (32) is fitted, which ensures a low frictional resistance when the band (5) is displaced over the guide surface of the band guide (17) and the blade carriage guide (7).