EP3771758A1

EP3771758A1 - Yarn-clamping device and weaving preparation machine including such a yarn-clamping device

Info

Publication number: EP3771758A1
Application number: EP19189417.9A
Authority: EP
Inventors: Martin FAEH; Stefan Ackermann
Original assignee: Staeubli Sargans AG
Current assignee: Staeubli Sargans AG
Priority date: 2019-07-31
Filing date: 2019-07-31
Publication date: 2021-02-03
Anticipated expiration: 2039-07-31
Also published as: CN112301519A; CN112301519B; EP3771758B1

Abstract

This yarn-clamping device (6) comprises a support member (166,186) forming a support surface extending along a longitudinal axis (X); a clamping bar (120) including a toothed surface (128) and a clamping surface (126) which faces the support surface along a transverse axis (Z), a first pressing rail (112) provided with a first complementary toothed surface (146) for cooperating with the toothed surface (128) of the clamping bar; and a first drive unit (132) for moving the first pressing rail (112) between a released position and a holding position, so that its first complementary toothed surface (146) cooperates with the toothed surface of the clamping bar to move the clamping surface (126) between a first open position, and a second closed position. The yarn-clamping device (6) also comprises a second pressing rail (114) provided with a second complementary toothed surface (148) for cooperating with the toothed surface (128) of the clamping bar (120) and a second drive unit (134) for moving the second pressing rail (114) between a released position and a holding position, so that the second complementary toothed surface (148) cooperates with the toothed surface of the clamping bar to move the clamping surface between the first open position and the second closed position. The first complementary toothed surface (146) faces a first longitudinal portion (128P1) of the toothed surface (128) of the clamping bar (120) and the second complementary toothed surface (148) faces a second longitudinal portion (128P2) of this toothed surface. The first and second complementary toothed surfaces (146, 148) are adjacent along the longitudinal axis (X) and they are moved, from their released positions to their holding positions, in the same longitudinal direction, for moving the clamping surface (126) from its first open position to its second closed position.

Description

TECHNICAL FIELD OF THE INVENTION

This invention relates to a yarn-clamping device for clamping a yarn layer. This invention also relates to a weaving preparation machine, in particular to a drawing-in machine, which includes, amongst others, such a clamping device.
The technical field of the invention is the one of warp yarn preparation for weaving looms.

BACKGROUND OF THE INVENTION

In the field of warp yarn preparation, EP-A-0 557 495 discloses a clamping device equipped with a clamping comb and clamping means formed by a toothed rail extending on the width of a yarn layer. The clamping comb and a reed comb are insertable in the yarn layer. On the other hand, the clamping means are provided with a toothed surface in engagement with a complementary toothed surface of a pressing rail which can be moved longitudinally by a slider. With this known device, the reed comb is moved longitudinally with respect to the clamping comb in order to deviate the yarns relative to lamellae of the clamping comb. Then, the toothed rail of the clamping bar causes relative movement between the clamping means and the clamping comb, towards the lamellae. The yarns are clamped between the support surface formed by the edges of the lamellae and the clamping means.
A problem with this known device is that, in case one has to work on a wide yarn layer, e.g. wider than 2.8 meters, one cannot guarantee a uniformed pressing force of the clamping means on the support surface, on the entire width of the yarn layer.

SUMMARY OF THE INVENTION

This invention aims at solving this problem by proposing a new clamping device, which allows a uniform clamping and a regular spacing of the warp yarns of a yarn layer, even for wide yarn layers, e.g. wider than 2.8 meters.
To this aim, the invention relates to a yarn-clamping device for clamping a yarn layer, this yarn-clamping device comprising a support member forming a support surface extending along a longitudinal axis, a clamping bar, including a toothed surface and a clamping surface which faces the support surface along a transverse axis perpendicular to the longitudinal axis. This yarn-clamping device includes a first pressing rail provided with a first complementary toothed surface shaped for cooperating with the toothed surface of the clamping bar. This yarn-clamping device also includes a first drive unit for moving the first pressing rail, between a released position and a holding position, along the longitudinal axis with respect to the toothed surface of the clamping bar, so that its first complementary toothed surface cooperates with the toothed surface of the clamping bar to move the clamping surface, in a direction parallel to the transverse axis, between a first open position, where yarns of the yarn layer are releasable between the support surface and the clamping surface, and a second closed position, where the clamping surface and the support surface cooperate, with the yarns in-between.
According to the invention, the yarn-clamping device also comprises a second pressing rail provided with a second complementary toothed surface shaped for cooperating with the toothed surface of the clamping bar. This yarn-clamping device also comprises a second drive unit for moving the second pressing rail, between a released position and a holding position, along the longitudinal axis with respect to the toothed surface of the clamping bar, so that its second complementary toothed surface cooperates with the toothed surface of the clamping bar to move the clamping surface in a direction parallel to the transverse axis, between the first open position and the second closed position. The first complementary toothed surface faces a first longitudinal portion of the toothed surface of the clamping bar, whereas the second complementary toothed surface faces a second longitudinal portion of the toothed surface of the clamping bar. The first and second complementary toothed surfaces of the first and second pressing rails are adjacent along the longitudinal axis. Moreover, theses toothed surfaces are moved, from their respective released positions to their respective holding positions, by the first and second drive units in the same longitudinal direction, for moving the clamping surface from its first open position to its second closed position.
Owing to the invention, the two pressing rails can be distributed along the longitudinal length of the clamping surface in order to exert respective pressing efforts on the two portions of the toothed surface of the clamping bar. This allows regularly distributing the pressing efforts along the length of the clamping surface, even if this clamping surface is more than 2.8 meters long. The clamping surface can be long enough to clamp all the yarns of a wide yarn layer, in particular a yarn layer with a width of more than 2.8 meters. Because the first and second complementary surfaces move in the same longitudinal direction when pushing the clamping surface toward its closed position, their teeth move in the same direction with respect to the teeth of the clamping bar. No antagonist movement is generated.
According to further aspects of the invention, which are optional, such a yarn-clamping device might incorporate one or several of the following features:

The first and second drive units are located at opposite longitudinal ends of the yarn-clamping device and in that a free end of the first pressing rail faces a free end of the second pressing rail along the longitudinal axis.
A longitudinal gap is formed between the first free end and the second free end and in that the longitudinal gap faces a third longitudinal portion of the toothed surface.
When the clamping surface is in its second closed position, a length of the gap is between 0.5 times and 1.5 times the tooth pitch of the toothed surface of the clamping bar, preferably less than 1 time this tooth pitch.
The support member comprises an open profile, which defines a longitudinal housing, in that a yarn-contacting member forms the support surface and is at least partly received in the longitudinal housing, and in that the yarn-contacting member is releasable from the longitudinal housing when the clamping surface is in its first open position.
The yarn-contacting member is a comb which includes lamellae, adjacent along the longitudinal axis and regularly distributed along the whole length of the clamping surface.
The toothed surface and/or the first and second complementary toothed surfaces are provided with tooth that are inclined with regard to the longitudinal axis and to the transverse axis.
The toothed surface of the clamping bar has a regular shape along its whole length and in that, when the clamping surface is in its second closed position, the first and second complementary toothed surfaces are in surface contact with the toothed surface.
In release position, each complementary toothed surface faces the corresponding longitudinal portion of the toothed surface of the clamping bar along the longitudinal axis over approximatively half the length of the toothed surface of the clamping bar.
Each drive unit includes
- a bracket maintained in longitudinal position relative to the support member;
- a slider longitudinally fastened to a respective pressing rail and movable along the longitudinal axis with respect to the bracket;
- a displacement mechanism articulated, around a first articulation axis, on the bracket and, around a second articulation axis, on the slider;
  - the displacement mechanism is configured for moving longitudinally the second articulation axis with respect to the bracket and spreading apart the first and second articulations axes along the longitudinal axis when moving the respective pressing rail from the release position to the holding position;
  - the second articulation axis of the first drive unit is located, along the longitudinal axis, between the clamping bar and the first articulation axis of the first drive unit; and
  - the first articulation axis of the second drive unit is located, along the longitudinal axis, between the clamping bar and the second articulation axis of the second drive unit.
The slider of the second drive unit is guided, in translation along the longitudinal axis, at least by the bracket of the second drive unit.
The clamping bar is articulated, via a coupling rod, at a first longitudinal end only, with the support member, around an axis perpendicular to the longitudinal and transverse axes.
The clamping bar includes a longitudinal profile which forms the clamping surface and several guiding members are located between the longitudinal profile and each pressing rail for guiding the movements of the longitudinal profile relative to each pressing rail, the guiding members allowing one of the first and second pressing rails to be in released position when the other pressing rail is in holding position.
A first distance, measured along the longitudinal axis, between two guiding members located between the longitudinal profile and one of the pressing rails, has a first value, whereas a second distance, measured along the longitudinal axis, between a first guiding member located between the longitudinal profile and the first pressing rail and a second guiding member located between the longitudinal profile and the second pressing rail, has a second value; and whereas the second value is strictly larger than the first value
The clamping surface is more than 2.8 meters long.

According to a second aspect, the invention relates to a weaving preparation machine, in particular to a drawing-in machine for drawing-in warp yarns into weaving harness elements, including a drawing-in unit and a yarn-clamping frame, this yarn-clamping frame including also at least one yarn-clamping device as mentioned here-above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and other advantages thereof will appear more clearly upon reading of the following description of one embodiment of a yarn-clamping device and a drawing-in machine according to the invention, provided solely as an example and made in reference to the appended drawings, in which:

figure 1 is a schematic perspective view of a drawing-in machine according to the invention;
figure 2 is a side view of a clamping device of the machine of figure 1 in open position, where some parts of the clamping device have been omitted, in particular a support member and a yarn-contacting member, for the sake of simplicity;
figure 3 is a side view, on a larger scale, of a first drive unit of the clamping device of figure 2;
figure 4 is a side view, at the same scale as figure 3, of a second drive unit of the clamping device of figure 2;
figure 5 is a side view, at a smaller scale, of the clamping device of figures 2 to 4 when this clamping device is in an intermediate position, with omission of the same parts as in figure 2;
figure 6 is a side view similar to figure 5, when the clamping device is in closed position;
figure 7 is a section along line VII-VII on figure 6, at a larger scale and
figure 8 is a section along line VIII-VIII on figure 6, at the same scale as figure 7, on which one yarn and the yarn contacting member are displayed.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The drawing-in machine 2 represented on figure 1 includes a drawing-in unit 3 for drawing-in warp yarns 502 of a yarn layer 500 coming from a non-represented warp beam through non-represented weaving harness elements of a weaving loom, such as heddles of heddle frames or drop wires.
This drawing-in machine 2 includes a supporting unit 4 for supporting the non-represented heddle frames or heddle rails and/or drop wires contacting rails and moving them in front of the drawing-in unit 3, according to the needs of the drawing-in process.
On all figures, X, Y and Z represent a set of three orthogonal axes, with axis X horizontal and parallel to the longest dimension of drawing-in machine 2, axis Y horizontal and perpendicular to axis X and axis Z perpendicular to axes X and Y, and vertical.
Axis X is parallel to the longest dimension of drawing-in machine 2 and defines the longitudinal direction of this machine. Axes Y and Z are transverse with respect to this longitudinal direction. Unless otherwise specified, a length of a part of the drawing-in machine 2 is measured parallel to axis X.
The yarn layer 500 is partly represented on figure 1. Its width W₅₀₀ is measured parallel to axis X and can be larger than 2.8 meters, preferably larger than 3.5, still preferably larger than 4 meters. In the portion of yarn layer 500 represented on figure 1, yarns 502 extend parallel to axis Z.
Drawing-in machine 2 comprises two clamping devices 6 and 7 spaced along axis Z and between which the yarns 502 of yarn layer 500 are positioned vertically, next to one another, and stretched.
Two lateral beams 8 and 9 connect the two clamping devices 6 and 7, on either side of the yarn layer 500. Parts 6, 7, 8 and 9 together form a yarn-clamping frame 10.
A brush-roller 11 is located next to the lower clamping device 7 and is used to stretch yarns 502 before clamping the yarns 502 with the clamping devices 6 and 7.
Here-after, the lower clamping device 6 is described in connection to figures 2 to 8. This description applies, mutatis mutandis, to the lower clamping device 7 which is designed according to the same principles.
Clamping device 6 includes a support member 102 made of several parts that are fastened together. There is no possibility of relative movement between these parts, along the longitudinal direction of axis X and along the transverse directions of axes Y and Z. These parts define together a sliding surface 106, which extends parallel to axis X. The support member is fixed on the structure of the yarn-clamping frame 10.
For the sake of simplicity, the support member 102 is partly represented only on figure 8, but the trace of surface 106 is identified on figure 2. The support member 102 is a metallic profile, which extends on the whole length of the clamping device 6. The support member 102 has, in cross-section perpendicular to axis X, an open shape, with a lateral opening 0102 visible on figure 8.
The clamping device 6 also includes a first pressing rail 112 and a second pressing rail 114, both shaped to slide along the sliding surface 106, in a direction parallel to axis X.
The clamping device 6 also includes a clamping bar 120 formed by an elongated profile 122 and a toothed rail 124 engaged within a longitudinal inner volume V122 of the profile 122. Parts 122 and 124 of the clamping bar 120 are fixed together, e.g. by welding, so that they move together in all directions with respect to the support member 102, as explained here below.
As visible on figure 8, the profile 122 has two branches 122A, 122B parallel to axes X and Z and one bottom 122C parallel to axes X and Y and to the sliding surface 106. The profile 122 defines a clamping surface 126, which is located at the distal end of an extension 127 of profile 122. This extension 127 protrudes externally from a junction zone between one branch 122B and the bottom 122C of the profile 122.
The surface 128 of the rail 124 opposite to bottom 122C of profile 122 is oriented toward the sliding surface 106 and provided with inclined teeth 128A, each tooth 128A being defined between a relatively long inclined surface 128B and a relatively short inclined surface 128C, like a saw-tooth profile. By inclined, one means that each surface 128B and 128C extends in an inclined direction with regard to axis X and to axis Z. Surfaces 128B preferably have an angle with axis X, taken in the toothed rail 124, within a range comprised between 15° and 40°, for example 20°. Surfaces 128B and 128C are perpendicular to each other. The shape of the toothed surface 128 is regular along its whole length, i.e. all the teeth 128A have the same geometry.
P128 denotes the pitch of the teeth 128A along axis X. P128 is chosen within a range comprised between 30 and 70 mm and preferably equal to 40 mm.
L120 denotes the total length of the clamping bar 120, this length being equal to the length of profile 122 measured along axis X and approximatively to the length of toothed rail 124 measured along this axis. This length L120 is also the longitudinal length of the clamping surface 126 and of the toothed surface 128.
Parts 122 and 124 are each made of a single piece and length L120 is, in this example, equal to about 3.6 meters. In practice, length L120 can be between 2.8 and 4 meters, or more. In particular, length L120 is higher than yarn layer width W₅₀₀.
A first drive unit 132 is provided for moving the first pressing rail 112 parallel to axis X, along the sliding surface 106, between a release position and a holding position. A second drive unit 134 is provided for driving the second pressing rail 114 parallel to axis X, along the sliding surface 106, between a release position and a holding position. These two drive units 132 and 134 are located at opposite longitudinal ends of the yarn-clamping device 6.
The first pressing rail 112 has a flat surface 142 for sliding on the sliding surface 106 and the second pressing rail 114 has a flat surface 144 for sliding on the sliding surface 106.
The surface 146 of the first pressing rail 112, opposite to surface 142, is provided with several teeth 146A, which are inclined with regard to the axis X and to the transverse axis Z and each defined between a relatively long surface 146B and a relatively short surface 146C. "Inclined" has here the same meaning as here-above.
Toothed surface 146 is complementary to toothed surface 128. In other words, the geometry of teeth 128A and 146A is complementary, the pitch P146 of the teeth 146A is the same as the pitch P128 and the surfaces 128 and 146 can lie against one another with a surface contact between surfaces 128B and 146B
Similarly, the second pressing rail 114 is provided, on its side opposite to its surface 144, with a toothed surface 148 complementary to toothed surface 128, with several teeth 148A having the same geometry as teeth 146A, and the same pitch as teeth 146A and teeth 128A. The teeth 148A are inclined with regard to the axis X and to the axis Z. Here again, toothed surfaces 128 and 148 can lie against each other with a surface contact between surfaces 128B and 148B.
As shown on figures 2, 5, 6 and 8, each pressing rail 112 or 114 is partly engaged in the longitudinal profile 122, between its branches 122A and 122B.
The length of the first pressing rail 112 is such that the complementary toothed surface 146 faces a first longitudinal portion of the toothed surface 128. This first longitudinal portion is identified with reference 128P1 on figure 2. In the release position of the first pressing rail 112, the length of this first portion 128P1 is about 50% of the length L120, which means between 40% and 60% of the length L120. Similarly, the length of the second pressing rail 114 is such that its complementary toothed surface 148 faces a second longitudinal portion of toothed surface 128. This second longitudinal portion is identified with reference 128P2 on figure 2. In the release position of the second pressing rail 114, the length of this second portion 128P2 is about 50% of the length L120, which means between 60% and 40% of the length L120, depending on the length of the first portion 128P1. Portions 128P1 and 128P2 are two different longitudinal portions of the same toothed surface 128; they do not overlap.
112A denotes a first longitudinal end of the first pressing rail 112, that is the free end of this rail, opposite to the first drive unit 132. Similarly, 114A denotes a first longitudinal end of the second pressing rail 114, opposite to the second drive unit 134. Both free ends 112A, 114A are in register with toothed surface 128, in a center longitudinal zone of this surface. Free ends 112A, 114A face each other along the axis X.
A longitudinal gap G is formed between first ends 112A and 114A, along toothed surface 128. d24 denotes the distance between these two ends 112A and 114A, that is the length of this gap G along axis X. This distance d24 is chosen between 0.5 times the pitch P128 and 1.5 times this pitch, preferably less than this pitch when the clamping bar is in closed position, as explained here below. For example, the distance d24 is chosen equal to 0.75 tooth pitch.
The length of the gap G being small as compared to the length L120, it can be considered as negligible with respect to the lengths of the complementary surfaces 146 and 148. Along axis X, the complementary surfaces 146 and 148 do not overlap and they are adjacent, with the gap G in-between.
The gap G faces a third longitudinal portion of the toothed surface 128 along axis X, the third longitudinal portion being identified with reference 128P3 on figure 2. The first longitudinal portion 128P1 is adjacent to the second longitudinal portion 128P2 with the third longitudinal portion 128P3 in-between, By "adjacent", one means here that the first and second longitudinal portions are in immediate proximity along axis X, since the length of third longitudinal portion is very small as compared to their respective lengths.
As more clearly visible on figure 3, the first drive unit 132 includes a first spindle 152, a first bracket 154, a first slider 156 and a first displacement mechanism 158 for moving the slider parallel to axis X.
The first displacement mechanism 158 is articulated on the bracket 154 around an axis X154 parallel to axis Y and on the slider 156 around another axis Y156 also parallel to axis Y. Axes Y154 and Y156 are defined by the respective longitudinal axis of two shafts 154A and 156A which respectively define a first articulation, between the first displacement mechanism 158 and the first bracket 154, and a second articulation, between this displacement mechanism and the first slider 156. The first displacement mechanism includes a first lever 160 and a first connecting bar 162 respectively articulated on the first bracket 154 and on the first slider 158 around axes Y154 and Y156 and together around an axis Y158 parallel to axes Y154 and Y156 and formed by a third shaft 158A.
The first slider 156 is rigidly connected to a second longitudinal end 112B of the first pressing rail 112, opposite to its first free end 112A, via two rivets 164. The shaft 154A has a non-circular head, for instance with six faces, which protrudes out of the first drive unit 132 and allows exerting around axis X154 a torque in order to actuate the first displacement mechanism 158 when necessary.
As shown on figure 3, the toothed rail 124 is articulated at a first longitudinal end 124A with a fixed frame 166 of the first drive unit 132 via a coupling rod 168. This frame 166 is a part of the support member 102. Longitudinal end 124A is also a longitudinal end of the clamping bar 120. Thus, the coupling bar 120 is articulated, via the coupling rod 168 and at the level of the longitudinal end 124A, on the support member 102. Coupling rod 168 is actually articulated on the frame 166 around a first axis Y166 and on the toothed rail 124 around a second axis Y124, these two axes being parallel to axis Y and distant from each other along axis X.
In this first drive unit 132, the second articulation formed around axis Y156 is located, along axis X, between the clamping bar 120 and the first articulation formed around axis Y154.
The second drive unit 134 includes a second spindle 172, a second bracket 174 and a second slider 176 connected to a second end 114B of the second longitudinal pressing rail 114, opposite to its first free end 114A, via two rivets 184. A second displacement mechanism 178 belongs to the second drive unit 134, allows controlling the position of the slider 176 along axis X and includes a second lever 180 and a second connecting bar 182.
A first articulation is formed, around an axis Y174 parallel to axis Y, between the second lever 180 and the second bracket 174. This axis Y174 is the central axis of a shaft 174A provided with a non-circular head, which protrudes out of a fixed frame 186 of the second drive unit 134, this fixed frame being also a part of the support member 102. It allows exerting a torque around axis Y174, as explained here above for shaft 154A.
A second articulation is provided, between the connecting bar 182 and the slider 176, around an axis Y176 parallel to axis Y and defined as the central axis of a shaft 176A.
The second lever 180 and the second connecting bar 182 are connected together by an articulation formed around an axis Y178, also parallel to axis Y and formed by the central axis of a shaft 178A.
Here, the first articulation formed around axis Y174 is located, along axis X, between the clamping bar 120 and the second articulation formed around axis Y176.
In the second drive unit 134, the slider 176 is guided, in its movement parallel to axis X, by the bracket 174 and by the frame 186. As shown on figure 7, the slider 176 is partially housed in the bracket 174. Two upper surfaces 176B of the slider 176 are in sliding contact against a lower surface 174B of the bracket 174. Moreover, a first lateral surface 176C of the slider 176 is in sliding contact against a lateral surface 174C of the bracket 174. In addition, a second lateral surface 176D of the slider 176, opposite to the first lateral surface 176C, is in sliding contact against an internal lateral surface 186D of the frame 186. Finally, two bottom surfaces 176E of the slider 176 are in sliding contact against a portion of the sliding surface 106 defined by the frame 186.
Thus, the slider 176 is efficiently guided in its translational movement along axis X and it can efficiently push or pull the second pressing rail 114 along this axis. The second drive unit 134 is compact.
Guiding means formed by guiding pads 192 are fixed by screws 194 to each pressing rail 112 of 114. These guiding pads 192 extend into dedicated grooves 196 formed in the elongated profile 122 of the clamping bar 120.
The grooves 196 have the same orientation relative to axes X and Z as the longer surface 128B of the teeth 128A. Thus, the grooves 196 are inclined with respect to axes X and Z.
The guiding pads 192 are provided for guiding a relative movement between the pressing rail 112 of 114 and the toothed rail 124 of the clamping bar 120. The guiding pads 192 are regularly spaced along axis X at the level of each pressing rail 112 or 114. d1 denotes the distance, measured parallel to axis X, between two adjacent guiding pads 192 mounted on the first pressing rail 112. d1' denotes the distance, measured parallel to axis X, between two guiding pads mounted on the second pressing rail 114.
In this example, distances d1 and d1' are equal. However, this is not compulsory.
One considers the guiding pad 192 mounted on the first pressing rail 112 in the closest position with respect to its first longitudinal end 112A. One considers also the guiding pad 192 mounted on the second pressing rail 114 in the closest position with respect to its first longitudinal end 114A. d2 denotes the distance, measured parallel to axis X, between these two adjacent guiding pads.
The distance d2 is chosen strictly larger than distances d1 and d1'. This facilitates relative movements between parts 112, 114 and 124.
When assembling the clamping device 6, the two pressing rails 112 and 114 and the two parts 122 and 124 of the clamping bar 120 are introduced within the inside volume of this support member 102, on one longitudinal side of the support member 102.
Once parts 112, 114, 122 and 124 are in place within the support member 102, a longitudinal housing H102 is defined within support member 102, between the clamping bar 120 and the support member 102 along the transverse axis Z, and a part of a comb 200 can be introduced within this housing, in particular the lamellae 202 of this comb which are regularly distributed along its length. The length of the comb 200 is approximatively equal to the length L120 of the clamping bar 120. By approximatively, one means that the difference between these two lengths is less than 5% of the shortest length.
The comb 200 forms a yarn-contacting member, which is designed as a removable part of the support member 102 and provided for contacting the yarns 502, as represented on figure 8, and for distributing them, as regularly as possible, between its lamellae 202.
When the comb 200 is partly in place in the housing H102, a support surface 204 formed by the comb 200 faces the clamping surface 126 along the transverse axis Z.
The clamping bar 120 is movable within the support member 102, along the direction of transverse axis Z, between a first open position represented on figure 2 and a second closed position represented on figures 6 and 8. In the first open position, the yarns 502 and the comb 200 can be freely introduced into the housing H102 or removed therefrom, via the opening 0102. When the comb 200 is in the housing H102, the clamping surface 126 in open position faces the support surface 204 along direction of axis Z. In the second closed position, the clamping surface 126 of the clamping bar 120 cooperates with the support surface 204 of the comb 200, with the yarns 502 in-between. The clamping surface 126 of the clamping bar 120 presses the yarns 502 against the support surface 204 formed by the comb 200. The yarns 502 are clamped between the support surface 204 and the clamping surface 126. They cannot slide relative to the comb 200 or to the support member 102. In this configuration, the clamping surface 126 presses the comb 200 upwardly on figure 8, so that the yarns 502 are also clamped between the comb 200 and an internal surface 108 of the support member 102.
In the first open position and second closed position of the clamping bar, the clamping surface 126 is parallel to axis X.
The clamping process of the yarns 502 of the yarn layer 500 occurs as follows:
The yarns 502 are first stretched with the brush-roller 11, so that they extend along directions parallel to axis Z. The first and second pressing rails 112 and 114 are then in a release position represented on figure 2, where they allow the clamping bar 120 and the toothed rail 124 to be in the open position, close to sliding face 106. In this first release position of the first and second pressing rails 112 and 114, the first and second pressing rails 112 and 114 are aligned along axis X. The toothed surface 128, the clamping surface 126 and the complementary toothed surfaces 146 and 148 extend along axis X. The teeth 128A of toothed surface 128 are imbricated with the teeth 146A and 148A of the complementary toothed surfaces 146 and 148. This configuration is compatible with the introduction of the yarn-contacting member formed by the comb 200 into the longitudinal housing H102. When the comb 200 is introduced within the housing H102, the yarns are distributed between the lamellae of the comb. In this configuration, the clamping surface 126 is remote from the support surface 204 and the clamping bar 120 is in its first open position, where the yarns 502 are releasable between surfaces 126 and 204, i.e. they can slide along their respective longitudinal direction relative to the open profile formed by this support member 102 and relative to the comb 200. In this first open position, the comb 200 locally deflects the yarns 502, since it pushes these yarns within the housing H102, but does not block them.
In a first clamping step, the operator rotates the shaft 154A of the first drive unit 132 around the first articulation axis Y154 so that the first lever 160 is rotated around this first articulation axis in the direction of arrow A1 on figure 5. This results in spreading apart, along axis X, axes Y154 and Y156. This results in pushing the first slider 156 towards the second drive unit 134, as shown by arrow A2 on figure 5.
Since the second articulation axis Y156 of the first drive unit 132 is located, longitudinally along axis X, between the clamping bar 120 and the first articulation axis Y154, the second articulation axis Y156 and the first slider 156 are thus moved towards the clamping bar 120 and the second drive unit 134. The first pressing rail 112, which is longitudinally fastened to the first slider 156, is also moved towards the second drive unit 134, thus towards the second pressing rail 114, in the direction of arrow A2, with the first longitudinal end 112A of the first pressing rail 112 coming closer to the first longitudinal end 114A of the second pressing rail 114. This is possible because of the length of the gap G, defined between ends 112A and 114A in a release position of the pressing rails 112 and 114, is not null and compatible with the movement of the pressing rail 112 during the first clamping step. The value of distance d24 is reduced during the movement between the position of figure 2 and the position of figure 5.
The first complementary toothed surface 146 of the first pressing rail 112 is in engagement with the toothed surface 128 of the toothed rail 124 and slides on this toothed surface 128. As the teeth 128A and 146A of the toothed surfaces 128 and 146 are inclined relative to axis X and Z, with the surfaces 128B being turned toward the first drive unit 132, the longitudinal movement of the first pressing rail 112 along the longitudinal axis X results in a movement of the toothed surface 128 in the direction of axis Z which results in a spreading of toothed surface 128 and sliding surface 106 in the direction of transverse axis Z. Teeth 146 and 128 are now imbricated by cooperation of the surfaces 146B and 128B with a smaller surface contact than in release position of the first pressing rail 112. Thus, the clamping bar 120 moves in the transverse direction of axis Z, from the open position of figure 2 to the intermediate position of figure 5, as shown by arrow A3 on figure 5. This movement of the clamping bar 120 in the direction of arrow A3 occurs in the direction of the yarn-contacting member formed by the comb 200 and with respect to the possibility of movement given by the articulation at the level of the coupling rod 168.
In this intermediate position, a portion of the clamping surface 126 of the clamping bar, which corresponds approximately to the portion aligned with the first portion 128P1 of toothed surface 128 along axis X, is pressed against the yarn-contacting member formed by the comb 200, with the yarns 502 in-between. In other words, the clamping surface 126 applies a first pressing effort E1 on the support surface 204 in the direction of axis Z,
In this intermediate position, the clamping bar 120 extend in an inclined and deformed configuration relative to the longitudinal direction of axis X, since only the first pressing rail 112 is in holding position and is pushing the clamping bar 120 toward the comb 200, whereas the second pressing rail 114 is still in its release position, so that the portion of the clamping bar 120 aligned with this second pressing rail 114 remains in the open position or close to the open position. Actually, a limited movement of the clamping bar 120 parallel to axis Z can occur in the portion of the clamping bar 120 close to the first longitudinal end 114A of the second pressing rail 114. This limited movement occurs thanks to the guiding pads 192 moving into the grooves 196. A clearance between an external surface of the guiding pads 192 and an internal surface of the grooves 196 allows such a limited movement for reaching the intermediate configuration.
On figure 5, portions 128P1, 128P2 and 128P3 of toothed surface 128 can be identified, even if the complementary toothed surfaces 146 and 148 have moved with respect to the toothed surface 128.
In a second clamping step, the shaft 174A of the second drive unit is rotated by the operator, as shown by arrow A4 on figure 6, around axis Y174, in the same rotating direction as arrow A1, which results in moving the second slider 176 along axis X, as shown by arrow A5, in the same direction along axis X as the movement of the first slider 156 identified by arrow A2 on figure 5. Because of its movement along axis X, in the direction of arrow A5, as the second pressing rail 114 is longitudinally fastened to the second slider 156, the second slider 176 pulls the second pressing rail in the same direction A5 and the complementary toothed surface 148 slides on this toothed surface 128. As the teeth 128A and 148A of the toothed surfaces 128 and 148 are inclined relative to axis X and Z, the longitudinal movement of the second pressing rail 114 in direction A5 results in a movement of the toothed surface 128 in the direction of axis Z that spreads toothed surfaces 128 and 148 in the direction of transverse axis Z. The teeth 148A of the complementary toothed surface 148 are now imbricated with the teeth 128A of the toothed surface 128 by cooperation of the surfaces 148B and 128B with a smaller surface contact than in release position of the pressing rail 114. Thus, the second pressing rail 114 moves from its release position to its holding position, where it exerts on the clamping bar 120 a second pressing effort E2 along axis Z toward the comb 200.
In other words, during this second clamping step, the toothed surface 148 of the second pressing rail 114 moves in the same longitudinal direction as the toothed surface 146 of the first pressing rail 112 in the first clamping step. This is due to the location of the first articulation axis Y174 of the second drive unit 134 between the clamping bar 120 and the second articulation axis Y176 and the second displacement mechanism 178 which spreads apart the first articulation axis Y174 and the second articulation axis Y176 of the second drive unit 134 between the release position and the holding position of the second pressing rail 114.
During this second clamping step, the second complementary toothed surface 148 slides along the toothed surface 128 of the toothed rail 124 and the guiding pads 192 guide this relative movement by cooperation of shapes with the grooves 196, as during the first clamping step.
Thus, the portion of the clamping surface 126 previously at distance from the support surface 204 is pushed by the second pressing effort E2 of the second pressing rail 114 towards the support surface 204. This moves the clamping bar 120 from its intermediate position to its second closed position, in a way similar to the one explained here-above for the passage of the open position of figure 2 to the intermediate position of figure 5.
This allows reaching the closed position of figure 6 where, as shown on figure 8, the clamping surface 126 efficiently presses the yarns 502 against the support surface 204.
In particular, as the shapes of complementary toothed surfaces 146 and 148 are identical and as the toothed surface 128 of the toothed rail 124 is regular along its whole length L120, the value of the displacement of the first pressing rail 112 in the direction of arrow A2 is approximately the same as the value for the displacement of the second pressing rail 114 in the direction of arrow A5.
The second clamping step increases the distance between the first free ends 112A and 114A, which, in holding position of the pressing rails 1142, 114, takes again the same value d24 as in the released position of the pressing rails 1142, 114, between 0.5 times the pitch P128 and 1.5 times this pitch, preferably less than this pitch, in the example equal to 0.75 tooth pitch.
With these two clamping steps, when the clamping bar is in closed position, the clamping surface 126 is substantially parallel to axis X and exerts a uniform clamping force on the yarn-contacting member on the whole length L120, with the yarns 502 in-between. The yarn-contacting member 200 is also pressed by the clamping surface 126 against the internal surface 108 of the support member 102, also with the yarns in-between. Thus, in this configuration, a movement of two portions of each yarn 502 is efficiently blocked with respect to the support member 102.
In this configuration also, by cooperation of shapes between the comb 200 and the support member 102 and between the comb 200 and the clamping bar 120, the clamping surface 126 blocks, a movement of the comb 200, in a direction parallel to axis Y, so that this yarn-contacting member cannot escape from the longitudinal housing H102 in the closed position of the clamping device.
When it is necessary to release the clamping effort on the yarns 502, the shafts 154A and 174A are rotated in directions opposite to the ones of arrows A1 and A4, one after the other. This causes the first and second sliders 156 and 176 to move along axis X in directions opposite to arrows A2 and A5. Here again, the two pressing rails 112 and 114 move in the same direction along axis X. The second articulation axis Y156 or Y176 of each drive unit 132 or 134 comes closer to the first articulation axis Y154 or Y176 and the pressing rails 112 and 114 are driven back into their respective release positions, which allows spreading the clamping surface 126 away from the yarns 502 and from the yarn-contacting member 200. In particular, the clamping surface 126 is moved away from the internal surface 108 of the support member 102, along axis Z.
This allows removing the yarn-contacting member formed by the comb 200 from the longitudinal housing H102 by an extraction movement parallel to axis Y, through the opening 0102, and releasing the yarns 502 out of the support member 102, as explained here above.
The spindles 152 and 172 are used, before the first and second clamping steps, to set the position of the brackets 154 and 174 with respect to the fixed frames 166 and 186, thus to the support member 102. In other words, the brackets 154 and 174 are maintained, or held, in longitudinal position relative to the support member 102 by the respective spindles 152, 172. This allows setting the intensity of the pressing efforts E1 and E2 and of the clamping force exerted by the clamping surface 126 on the yarns 502 in the second closed position.
Some advantages of the invention are as follows:
All the yarns 502 can be clamped by the regular continuous clamping surface 126 extending on the whole length L120, even at the level of the gap G. Thus, there is no irregular gap between the yarns within the yarn layer 500, in particular in a central area that would correspond roughly to the zone of the gap G. This is particularly important for layers including lease cords.
The longitudinal movements of the first and second pressing rails 112 and 114 obtained in the first and second clamping steps occur in the same direction, which causes their teeth 146A and 148A to be displaced relative to the teeth 128A of the clamping bar 120 in the same direction. These two movements are not antagonist and the second pressing effort E2 obtained with the movement of the second pressing rail 114 from its release position to its holding position confirms the pressing effort E1 obtained by the movement of the first pressing rail 112 from its release position to its holding position.
Since the first and second drive units 132 and 134 are placed on opposite sides of the clamping bar 120, the size of the clamping device in the transverse direction can be reduced. These two drive units move the two pressing rails in the same longitudinal direction, which avoid counteracting clamping efforts and yarn irregularities within the yarn layer 500.
The yarn-contacting member is in the form of a comb 200 with regularly distributed lamellae. This allows a regular repartition of the yarns, in the clamping device in order to press each yarn 502 against the support surface 204.
The regular toothed geometry of the toothed surface 128 of the clamping bar 120 allows the operator to start the clamping or release process from the right or from the left, without any incidence. With this respect, in the description here-above, the example is given when starting the clamping process with the first drive unit 132 and the first pressing rail 112. Alternatively, it is possible to start with the second drive unit 134 and the second pressing rail 114.
Thanks to the articulation of the clamping bar 120 with the support member 102 on one longitudinal end only, via the coupling rod 168, the guiding pads 192 and grooves 196 allow a movement of the clamping bar 120 in two steps, without a risk of blocking these means.
Since the guiding pads 192 are more widely spaced in the vicinity of the longitudinal gap G between the free ends 112A and 114A of the two pressing rails 112 and 114, because distance d2 is strictly larger than distances d1 and d1', a deformation of the clamping bar is allowed between the open position and the intermediate position, after the first clamping step, and between the intermediate position and the closed position, after the second clamping step.
Several modifications of the embodiment represented on the figures can be considered.
According to an alternative embodiment of the invention, which is not represented, the profile 122 and the toothed rail 124 of the clamping bar 120 can be designed as a unitary part.
Instead of being articulated with the first drive unit 132, the toothed rail 124 of the clamping bar 120 can be articulated with the second drive unit 134, via a coupling rod similar to coupling rod 168.
The complementary toothed surface of the two pressing rails 112 and 114 can have a distribution different from about 50% of the total length L120. For instance, their repartition can be 1/3 versus 2/3 or any other distribution, for which the first complementary toothed surface 146 covers a first portion of the toothed surface 128 whereas the second complementary toothed surface 148 covers a second portion of this toothed surface 128, the first and second portions not overlapping each other along the axis X.
The invention is represented on the figures in case the yarn layer 500 extends vertically between clamping devices 6 and 7. However, other configurations are possible. In particular, the yarn clamping frame can be pivoted, for installing and for clamping the yarns with clamping devices 6 and 7, so that the yarn layer 500 is horizontal or substantially horizontal. Then, the transverse axis is also horizontal. In such a case, for the drawing-in process, the yarn clamping frame is pivoted again to place the yarns 502 in vertical direction, along axis Z.
The invention is described here-above in case it is implemented on a drawing-in machine 2, which is particularly advantageous. Such drawing-in machine is shown in EP-A-2 199 443 whose content is incorporated in this description by reference. However, the invention can also be implemented with a tying machine, a leasing machines or any other weaving preparation machine, for which a yarn layer clamping is needed. In case the invention is used with a tying machine, its clamping frame or tying frame can include four yarn-clamping devices, i.e. two yarn-clamping devices per warp layer, as shown in EP-A-0 590 120 , whose content is incorporated in this description by reference. In case the weaving preparation machine on which the clamping frame of the invention is used includes two yarn-clamping devices, only one of them can be made according to the invention, the other one being different.
According to another alternative and non-represented embodiment of the invention, the support surface of the yarn-contacting member, equivalent to support surface 204 identified here-above, can be formed by edges of the lamellae of a comb, as considered in EP-A-0 557 495 . In that case, the support surface extends along the whole longitudinal direction of the yarn layer, is regular but it is discontinuous.
According to another alternative embodiment of the invention, no yarn-contacting member is used. In such a case, the support member 102 is adapted to receive the yarns 502 and the clamping surface 126 directly faces the internal surface 108 of the open profile formed by the support member 102. The clamping surface 126 cooperates with the internal surface 108, with the yarns 502 in-between, in the closed position of the clamping bar, the internal surface 108 forming a support surface in the meaning of the invention, in order to block the yarn 102 when necessary.
Alternative clamping bars can be considered, such as a toothed rail 124 made up of several longitudinal parts secured together for forming a whole, with a continuous toothed surface 128 extending on the whole length of the clamping bar, or such as an elongated profile 122 made up of several longitudinal parts secured together for forming a whole, with a continuous clamping surface extending on the whole length of the clamping bar.
Alternative yarn-contacting members can be considered, such as a profile rail without lamellae.
The embodiment, variants and alternative embodiments considered here above may be combined in order to generate new embodiments of the invention.

Claims

A yarn-clamping device (6) for clamping a yarn layer (500), this yarn-clamping device comprising:
- a support member (102) forming a support surface (204) extending along a longitudinal axis (X);

- a clamping bar (120) including a toothed surface (128) and a clamping surface (126) which faces the support surface (204) along a transverse axis (Z) perpendicular to the longitudinal axis (X);

- a first pressing rail (112) provided with a first complementary toothed surface (146) shaped for cooperating with the toothed surface (128) of the clamping bar; and

- a first drive unit (132) for moving the first pressing rail (112) between a released position and a holding position, along the longitudinal axis (X) with respect to the toothed surface (128) of the clamping bar (120), so that its first complementary toothed surface (146) cooperates with the toothed surface of the clamping bar to move (A3) the clamping surface (126), in a direction parallel to the transverse axis (Z), between a first open position, where yarns (502) of the yarn layer (500) are releasable between the support surface (204) and the clamping surface (126), and a second closed position, where the clamping surface and the support surface cooperate, with the yarns in-between;
characterized in that
- the yarn-clamping device also comprises a second pressing rail (114) provided with a second complementary toothed surface (148) shaped for cooperating with the toothed surface (128) of the clamping bar (120);

- the yarn-clamping device also comprises a second drive unit (134) for moving the second pressing rail (114) between a released position and a holding position, along the longitudinal axis (X), with respect to the toothed surface (128) of the clamping bar (120), so that the second complementary toothed surface (148) cooperates with the toothed surface of the clamping bar to move (A6) the clamping surface, in the direction parallel to the transverse axis (Z), between the first open position and the second closed position;

- the first complementary toothed surface (146) faces a first longitudinal portion (128P1) of the toothed surface (128) of the clamping bar (120) and the second complementary toothed surface (148) faces a second longitudinal portion (128P2) of the toothed surface of the clamping bar;

- the first and second complementary toothed surfaces (146, 148) of the first and second pressing rails (112, 114) are adjacent along the longitudinal axis (X); and

- the first and second complementary toothed surfaces (146, 148) of the first and second pressing rails (112, 114) are moved, from their respective released positions to their respective holding positions, by the first and second drive units (132, 134) in the same longitudinal direction (A2, A5), for moving the clamping surface (126) from its first open position to its second closed position.
The yarn-clamping device of claim 1, characterized in that the first and second drive units (132, 134) are located at opposite longitudinal ends of the yarn-clamping device (6) and in that a free end (112A) of the first pressing rail (112) faces a free end (114A) of the second pressing rail (114) along the longitudinal axis (X).
The yarn-clamping device of claim 2, characterized in that a longitudinal gap (G) is formed between the first free end (112A) and the second free end (114A) and in that the longitudinal gap (G) faces a third longitudinal portion (128P3) of the toothed surface (128).
The yarn-clamping device of claim 3, characterized in that, when the clamping surface (126) is in its second closed position, a length (d24) of the gap (G) is between 0.5 times and 1.5 times the tooth pitch (P128) of the toothed surface (128) of the clamping bar (120), preferably less than 1 time this tooth pitch.
The yarn-clamping device of any one of the preceding claims, characterized in that the support member comprises an open profile (102), which defines a longitudinal housing (H102), in that a yarn-contacting member (200) forms the support surface (204) and is at least partly received in the longitudinal housing, and in that the yarn-contacting member is releasable from the longitudinal housing when the clamping surface (126) is in its first open position.
The yarn-clamping device of claim 5, characterized in that the yarn-contacting member is a comb (200) which includes lamellae (202), adjacent along the longitudinal axis and regularly distributed along the whole length of the clamping surface (126).
The yarn-clamping device of any one of the preceding claims, characterized in that the toothed surface (128) and/or the first and second complementary toothed surfaces (146, 148) are provided with tooth (128A, 146A, 148A) that are inclined with regard to the longitudinal axis (X) and to the transverse axis (Z).
The yarn-clamping device of any one of the preceding claims, characterized in that the toothed surface (128) of the clamping bar (120) has a regular shape along its whole length (L120) and in that, when the clamping surface (126) is in its second closed position, the first and second complementary toothed surfaces (146, 148) are in surface contact with the toothed surface (128).
The yarn-clamping device of any one of the preceding claims, characterized in that, in release position, each complementary toothed surface (146, 148) faces the corresponding longitudinal portion (128P1, 128P2) of the toothed surface (128) of the clamping bar (120) along the longitudinal axis (X) over approximatively half the length (L120) of the toothed surface (128) of the clamping bar (120).
The yarn-clamping device of any one of the preceding claims, characterized in that
- each drive unit (132, 134) includes
- a bracket (154, 174) maintained in longitudinal position relative to the support member (102);

- a slider (156; 176) longitudinally fastened to a respective pressing rail (112, 114) and movable along the longitudinal axis (X) with respect to the bracket;

- a displacement mechanism (158, 178) articulated, around a first articulation axis (Y154, Y174), on the bracket and, around a second articulation axis (Y156, Y176), on the slider;

- the displacement mechanism (158, 178) is configured for moving longitudinally the second articulation axis (Y156, Y176) with respect to the bracket (154, 174) and spreading apart the first and second articulations axes (Y154-Y156, Y174-Y176) along the longitudinal axis (X) when moving the respective pressing rail (112, 114) from the release position to the holding position;

- the second articulation axis (Y156) of the first drive unit (132) is located, along the longitudinal axis (X), between the clamping bar (120) and the first articulation axis (154) of the first drive unit (132); and

- the first articulation axis (Y174) of the second drive unit (134) is located, along the longitudinal axis, between the clamping bar (120) and the second articulation axis (Y176) of the second drive unit (134).
The yarn-clamping device of claim 10, characterized in that the slider (176) of the second drive unit (134) is guided, in translation (A5) along the longitudinal axis (X), at least by the bracket (174) of the second drive unit.
The yarn-clamping device of any one of the preceding claims, characterized in that the clamping bar (120) is articulated, via a coupling rod (168), at a first longitudinal end (124A) only, with the support member (102), around an axis (Y166) perpendicular to the longitudinal and transverse axes (X, Z).
The yarn-clamping device of any one of the preceding claims, characterized in that
- the clamping bar (120) includes a longitudinal profile (122) which forms the clamping surface (126);

- several guiding members (192) are located between the longitudinal profile and each pressing rail (112, 114) for guiding the movements of the longitudinal profile relative to each pressing rail, the guiding members (192) allowing one of the first and second pressing rails (112, 114) to be in released position when the other pressing rail is in holding position (Fig 5).
The yarn-clamping device of any one of the preceding claims, characterized in that the clamping surface (126) is more than 2.8 meters long.
A weaving preparation machine, in particular a drawing-in machine (2) for drawing-in warp yarns into weaving harness elements, including a drawing-in unit (3) and a yarn-clamping frame (10), characterized in that the yarn-clamping frame (10) includes at least one yarn-clamping device (6) according to one of the preceding claims.