EP3655574B1

EP3655574B1 - Shed-forming device for a weaving machine

Info

Publication number: EP3655574B1
Application number: EP18758962.7A
Authority: EP
Inventors: Hannes CHRISTIAENS; Frederik DE MEDTS; Matthew Theobald; Bram Vanderjeugt
Original assignee: Vandewiele NV
Current assignee: Vandewiele NV
Priority date: 2017-07-20
Filing date: 2018-07-20
Publication date: 2021-09-08
Anticipated expiration: 2038-07-20
Also published as: WO2019016773A1; EP3655574A1; BE1025414A1; BE1025414B1

Description

The present invention relates to, on the one hand, a shed-forming device for a weaving machine, comprising a first pulley element and a second pulley element, lifting and selection means in order to, in successive shed-forming cycles, bring the first pulley element into a top position or a bottom position, as desired, and bring the second pulley element into a top position or a bottom position, as desired, and a pulley cord which is connected to a heddle for positioning at least one warp thread on a weaving machine and which cooperates with the first and the second pulley element in such a way that the heddle can be brought to four different heights, depending on the positions of the two pulley elements.
The present invention relates in particular to a jacquard machine, comprising a number of shed-forming devices which have the properties mentioned in the preceding paragraph and each heddle of which in each shed-forming cycle can be brought to one of four different heights, as desired, according to the open-shed principle. More specifically, the present invention relates to an open-shed jacquard machine with four positions.
On the other hand, the present invention relates to a shed-forming device for a weaving machine, comprising a first pulley element and a second pulley element, lifting and selection means in order to, in successive shed-forming cycles, bring the first pulley element into a top position or a bottom position, as desired, and to bring the second pulley element into a top position or a bottom position, as desired, a first pulley cord and a second pulley cord which are connected to a respective heddle for positioning at least one warp thread on a weaving machine, wherein the first pulley cord cooperates with the first pulley element in such a way that the heddle connected thereto can be brought to two different heights, depending on the position of the first pulley element, and wherein the second pulley cord cooperates with the second pulley element in such a way that the heddle connected thereto can be brought to two different heights, depending on the position of the second pulley element.
The present invention also relates to, in particular, a jacquard machine comprising a number of shed-forming devices which have the properties indicated in the preceding paragraph, and the respective heddles of which in each shed-forming cycle can be brought to one of two different heights, as desired, according to the open-shed principle. More specifically, the present invention relates to an open-shed jacquard machine with two positions.
During weaving of a fabric on a weaving machine, during the successive weaving cycles, warp threads are positioned with respect to one or more levels on which a respective weft thread is inserted in each weaving cycle. This positioning of warp threads is referred to as the shed formation. In this case, the positions of the warp threads in the successive weaving cycles are determined in such a way that the application of the weaving process results in a fabric with a predetermined weaving pattern. This positioning of warp threads with respect to one or more weft insertion levels on a weaving machine is brought about automatically by means of a shed-forming device.
With known shed-forming devices, every warp thread to be positioned passes through an eyelet of a heddle. At the bottom, each heddle is connected to a return spring which exerts a downwardly directed force on the heddle and, at the top, is connected, via a harness cord, to the end of a position-determining pulley cord which is situated at a higher level and forms part of a pulley device.
The pulley elements can be brought into their top and their bottom position as a result of the fact that they are supported by a supporting pulley cord, the ends of which are connected to a respective hook of a cooperating hook pair. Each of these hooks can be moved in a vertical direction and can be brought into a top and a bottom position. If the two hooks of a hook pair are both situated in their top position, the pulley element supported by this hook pair has been brought into its top position. If one hook of the hook pair is situated in its top position, while the other hook is situated in its bottom position, the pulley element supported by this hook pair has been brought into its bottom position.
In order to move the hooks between their bottom and their top position, two elongate blades are provided which are driven, in opposite phases with respect to each other, to perform an up and down movement. Every hook of a hook pair may be carried along by a respective blade and be moved upwards and downwards. Each time a hook comes in the vicinity of its top position, this hook may, as desired, either be selected so that it is held in its top position while the associated blade is moved downwards, or not be selected, so that it is moved downwards by the associated blade. Selection is brought about, for example, by energizing an electromagnetic coil as a result of which the hook is moved or deformed in such a way that the hook hooks into a fixed support edge.
By optionally selecting the respective cooperating hooks, each pulley element in each shed-forming cycle can be brought into a top or a bottom position, as desired. The four different combinations of top and bottom positions of the two pulley elements of a shed-forming device with four positions result in four different positions of the heddle. With a shed-forming device with two positions, the top and the bottom position of each pulley element result in a top and a bottom position of the associated heddle.
EP 0 665 312 A1 describes such an open-shed jacquard machine with four positions. In each shed-forming device, the two cooperating pulley elements are arranged next to each other along the longitudinal direction of the blades, as a result of which they take up considerable space.
EP 1 111 107 A1 describes a shed-forming device in which a first and a second hook pair support a respective pulley element. In a specific embodiment (Figs. 9 and 10), a pulley cord is provided which cooperates with both pulley elements and is connected to a heddle, so that the pulley cord can bring about three positions of the heddle. In another embodiment (Figs. 5 and 6), the two pulley elements cooperate with a respective pulley cord which is connected to a heddle, so that each pulley cord can bring about two positions of the respective heddles. In these two embodiments, the two pulley elements are placed one below the other, but in order to allow the pulley cords which run from the top pulley element vertically downwards to run freely along the bottom pulley element, the pulleys of these pulley elements have to operate in parallel planes or at least one of the pulleys has an operating plane which is oblique with respect to the operating planes of the other pulleys. Such a shed-forming device is of a relatively complicated construction and is not compact.
EP 0 839 937 A1 describes a shed-forming device, a first and a second hook pair of which support a respective pulley element, and which comprises a pulley cord which cooperates with these two pulley elements and is connected to a heddle. The one pulley element is movable in a vertical direction in the intermediate space between a top and a bottom pulley of the other pulley element, so that the pulley elements take up relatively little space along the direction of the blades. The hooks of the first hook pair can be moved in a vertical direction by a respective blade, but the hooks of the second hook pair can only be moved up and down while supported by a respective hook of the first hook pair. The hooks of the second hook pair can thus only be moved up and down if the associated hook of the first hook pair is also moved. This shed-forming device is not suitable for bringing the heddle in each shed-forming cycle to one of four different heights as desired. The different combinations of top and bottom positions of the two pulley elements of EP 0 839 937 A1 do not result in four different positions of the heddle.
A shedding device according to the preamble of claim 1 is known from EP 1 939 338 A1 .
Generally, jacquard machines are provided with a large number of shed-forming devices. Due to the increasing demand for jacquard machines with two positions and jacquard machines with four positions with increasingly large numbers of shed-forming devices, it is desirable to further reduce the footprint of the shed-forming devices. The footprint is the surface area which a shed-forming device occupies in a perpendicular projection on a horizontal plane. In addition, it is also desirable to produce shed-forming devices which are simple and compact and easily assemblable. These objects are achieved by providing a shed-forming device having the characterizing features indicated in the first paragraph of the present description, in which, according to the present invention, the second pulley element is movable between its top and its bottom position in a movement space which is located at least partly within the space occupied by the first pulley element, both when the first pulley element has been brought into its top position and when it has been brought into its bottom position.
Below, this shed-forming device is also referred to as the shed-forming device with four positions according to the invention.
This object is also achieved by providing a shed-forming device having the characterizing features indicated in the third paragraph of this description, in which, according to the present invention, the second pulley element is movable between its top and its bottom position in a movement space which is located at least partly within the space occupied by the first pulley element, both when the first pulley element has been brought into its top position and when it has been brought into its bottom position.
Below, this shed-forming device is also referred to as the shed-forming device with two positions according to the invention.
The expression 'space occupied by the first pulley element' in the description and the claims of this patent application is understood to mean the beam-shaped space which surrounds the first pulley element or, in other words, the space which is delimited by a beam whose surface area is formed by a horizontal upper face which touches the top side of the first pulley element, a horizontal lower face which touches the bottom side of the first pulley element, a first and a second lateral face which run parallel with the plane in which the blades extend, respectively touching opposite sides of the first pulley element, and a third and a fourth lateral face which are perpendicular to the first and the second lateral face, respectively touching opposite sides of the first pulley element.
The expression 'movement space of the second pulley element' in the description and the claims of this patent application is understood to mean the surrounding beam-shaped space in which the second pulley element, in a given position of the first pulley element, can move between its top position and its bottom position or, in other words, the space which is delimited by a beam whose surface area is formed by a horizontal upper face which touches the top side of the second pulley element when it is in its top position, a horizontal lower face which touches the bottom side of the second pulley element when it is in its bottom position, a first and a second lateral face which run parallel with the plane in which the blades extend, respectively touching opposite sides of the second pulley element, and a third and a fourth lateral face which are perpendicular to the first and the second lateral face, respectively touching opposite sides of the second pulley element.
Due to the fact that one pulley element is incorporated in the other while the two pulley devices are still able to operate independently of each other's position and be moved between a top and a bottom position, a very compact and reliable shed-forming device is obtained comprising pulleys whose operating planes can be in the same vertical plane and comprising pulley cords which may also extend next to each other in one vertical plane and may freely pass through. This results in a shed-forming device with two positions and a shed-forming device with four positions which have a smaller footprint than the known shed-forming devices with two positions and the known shed-forming devices with four positions. In addition, a space saving along the longitudinal direction of the blades is achieved, which is most advantageous.
Moreover, the fact that the pulley elements are now combined in pairs to form a compact unit, facilitates assembly and the preassembly of the shed-forming devices on a weaving machine.
By means of a shed-forming device with two positions according to the invention two (groups of) warp threads can be brought to two different heights independently of each other. Thus, two shed-forming devices with two positions are combined to form one shed-forming device with a footprint which is barely larger than the footprint of one existing shed-forming device. Compared to existing jacquard machines, a jacquard machine with two positions provided with a number of such shed-forming devices will have a smaller total footprint or will be able to position a larger number of heddles on the same footprint.
In a preferred embodiment of the shed-forming device with four positions according to the invention, the lifting and selection means comprise a first pair of hooks and a second pair of hooks and they are provided to hold each hook at a first height or bring it to a second height, as desired, the first pulley element can be brought to a top and a bottom position by the hooks of the first pair and the second pulley element can be brought to a top and a bottom position by the hooks of the second pair.
In a first particularly preferred embodiment, this shed-forming device comprises a first and a second fixedly arranged pulley and one end of the pulley cord is connected to a fixed point and the other end is connected to the heddle, and the pulley cord successively runs from one end over a pulley of the first pulley element, under the first fixed pulley, over a pulley of the second pulley element, under the second fixed pulley and over a pulley of the second pulley element.
In this embodiment, the movement of the second pulley element is doubled. An upward or downward movement of the second pulley element over a specific height, with the first pulley element remaining at the same height, then results in the heddle being moved over double this height upwards or downwards. An upward or downward movement of the first pulley element over a specific height, with the second pulley element remaining at the same height, then preferably results in the heddle being moved upwards or downwards over the same height.
In a second particularly preferred embodiment, this shed-forming device comprises a first and a second fixedly arranged pulley and one end of the pulley cord is connected to a fixed point and the other end is connected to the heddle, and the pulley cord successively runs from one end over a pulley of the first pulley element, under the first fixed pulley, over a pulley of the first pulley element, under the second fixed pulley and over a pulley of the second pulley element.
With this embodiment, the movement of the first pulley element is doubled. An upward or downward movement of the first pulley element over a specific height while the second pulley element remains at the same height, then results in the heddle being moved over double this height upwards or downwards. An upward or downward movement of the second pulley element over a specific height while the first pulley element remains at the same height, then preferably results in the heddle being moved upwards or downwards over the same height.
In an advantageous embodiment, a horizontal plane, under the first pulley element and above the fixed point to which one end of the pulley cord is connected, is crossed at six different locations by the pulley cord and these six locations are situated in a line.
Said line is preferably in the operating plane of the pulleys or runs parallel to the operating plane of the pulleys. In other words, the juxtaposed vertical pulley cord parts of the pulley cord which is connected to the heddle are preferably in the same vertical plane and this plane preferably runs parallel with, or coincides with, the operating plane of the pulleys.
The operating plane of the pulleys is the vertical plane which coincides with the vertical planes of symmetry of the respective pulleys. These planes of symmetry run parallel to the flanks of the pulleys and divide the pulleys into two equal halves.
The operating plane of the pulley device is preferably also perpendicular to the longitudinal direction of the blades. The blades extend, for example, in the width direction of the weaving machine over a certain length.
As already mentioned above, this benefits the compact design of the shed-forming device.
In a preferred embodiment of the shed-forming device with two positions according to the invention the lifting and selection means comprise a first pair of hooks and a second pair of hooks and they are provided to hold each hook at a first height or bring it to a second height, as desired, the first pulley element can be brought to a top and a bottom position by the hooks of the first pair, and the second pulley element can be brought to a top and a bottom position by the hooks of the second pair.
The shed-forming device comprises, for example, two blades which can be driven to perform an up and down movement, in opposite phases with respect to each other. In this case, two hooks may be carried along by the one blade and two hooks by the other blade, in which case one hook of the first hook pair and one hook of the other hook pair may be carried along by the same blade. The hooks which can be carried along by the same blade may be moved by the blade or selected to be held at a fixed height independently of each other. One hook comprises, for example, two parts which are connected to each other and between which a free space is left, while the other hook may be moved up and down in this free space, irrespective of the position of the one hook.
In a particularly preferred embodiment, the first pulley cord is connected at one end to a fixed point of the device, runs over a pulley of the first pulley element and is connected to a first heddle at the other end, and the second pulley cord is connected at one end to a fixed point of the device, runs over a pulley of the second pulley element and is connected to a second heddle at the other end.
In another particularly preferred embodiment, the first pulley element comprises two pulleys between which a vertical intermediate space is provided and the second pulley element, which is at least partly located inside this vertical intermediate space, is movable up and down between its top and its bottom position.
The first pulley element preferably comprises a guide means which is provided to guide the second pulley element during its movements between its top and its bottom position. This guide means preferably comprises two holder plates between which the pulleys of the first pulley element are rotatably fitted, wherein the second pulley element is movable up and down in the vertical intermediate space between the pulleys of the first pulley element and is held and guided between the said holder plates during these movements.
In an advantageous embodiment, a first horizontal plane, under the first pulley element and above the fixed point to which one end of the first pulley cord is connected, is crossed at two locations by the first pulley cord and a second horizontal plane, under the second pulley element and above the fixed point to which one end of the second pulley cord is connected, is crossed at two locations by the second pulley cord, and the vertical projection in a third horizontal plane of the two locations on the first horizontal plane and of the two locations on the second horizontal plane is in a line.
Said line is preferably in the operating plane of the pulleys or runs parallel to the operating plane of the pulleys. In other words, the vertical lines according to which the vertical parts of the pulley cords which are connected to the heddles preferably extend in the same vertical plane and this plane preferably runs parallel with, or coincides with, the operating plane of the pulleys. The operating plane of the pulleys is the vertical plane which coincides with the vertical planes of symmetry of the respective pulleys. These planes of symmetry run parallel with the flanks of the pulleys and divide the pulleys into two equal halves.
The operating plane of the pulley device is preferably also perpendicular to the longitudinal direction of the blades. The blades extend either in the width direction of the weaving machine or perpendicular to the width direction of the weaving machine over a specific length.
As has already been mentioned above, this benefits the compact design of the shed-forming device.
In preferred embodiments of the shed-forming device with two positions and the shed-forming device with four positions according to the invention, the lifting and selection means comprise two first hooks which are provided next to each other at a distance apart and are movable up and down and two second hooks which are provided next to each other at a distance apart and are movable up and down, the lifting and selection means comprise, for each hook, a respective selection means to either select the hook so that the hook is held at a first height or not to select the hook, as desired, so that the hook is moved to a second height, respective first selection means are provided next to each other for the two first hooks in a first selection element between these first hooks, respective second selection means are provided next to each other for the two second hooks in a second selection element between these second hooks and the first selection element and the second selection element are situated one above the other.
The hooks cooperating with the first pulley element are referred to as the first hook pair or the first hooks. The hooks cooperating with the second pulley element are referred to as the second hook pair or the second hooks. The preferred embodiments according to the preceding paragraph are preferably carried out such that one first hook and one second hook are situated on one side of the selection elements and that the other first hook and the other second hook are situated on the other side of the selection elements.
There now follows a more detailed description of an embodiment of a shed-forming device with two positions according to the invention and of two different embodiments of a device with four positions according to the invention in order to illustrate the invention and to indicate further characterizing features thereof. In this description, the operation of these shed-forming devices will also be explained in more detail.
It will be clear that the embodiments of the shed-forming devices according to the present invention described below are only some of the numerous possible embodiments which fall within the scope of protection of the patent which is defined in the attached claims and that nothing in the following description may be considered to be a limitation of this scope of protection.
Reference numerals are used in this description to refer to the attached drawings, in which:

▪ Fig. 1 is a diagrammatic representation of two shed-forming devices with two positions according to the present invention;
▪ Figs. 2a, 2b, 2c and 2d are diagrammatic representations of the four different positions of a shed-forming device with two positions according to the present invention;
▪ Figs. 3a, 3b, 3c and 3d are diagrammatic representations of the four different positions of a first embodiment of a shed-forming device with four positions according to the present invention;
▪ Figs. 4a, 4b, 4c and 4d are diagrammatic representations of the four different positions of a second embodiment of a shed-forming device with four positions according to the present invention;
▪ Fig. 5 diagrammatically shows the first and second pulley elements supported by hooks and pulley cords in perspective, in which the first pulley element is in its top position and in which both the movement space of the second pulley element and the space which the first pulley element occupies are indicated as beam-shaped spaces by means of dash-dotted lines, and
▪ Fig. 6 diagrammatically shows the first and second pulley elements supported by hooks and pulley cords in perspective, in which the first pulley element is in its bottom position and in which both the movement space of the second pulley element and the space which the first pulley element occupies are indicated as beam-shaped spaces by means of dash-dotted lines.

A shed-forming device with two positions according to the present invention (see Fig. 1) comprises two pulley cords (13), (14) which cooperate with respective pulley elements (1), (2). Each pulley cord (13), (14) is connected to a fixed point of the device by its one end (13a), (14a) and connected to a respective heddle (30), (31) by its other end (13b), (14b). The two heddles (30), (31) are provided with a heddle eyelet (30a), (31a) and are connected at the bottom to one side of a respective return spring (32), (33) whose other side is connected to a fixed point of the device and which exerts a downwardly directed force on the heddle (30), (31). On a weaving machine, one or more warp threads (not shown in the drawings) extend through each heddle eyelet (30a), (31a).
The first pulley element (1) comprises two elongate holder plates (1d), (1e) which extend vertically (see also Figs. 5 and 6). In the vicinity of the top and the bottom end of the holder plates, a top pulley (1a) and a bottom pulley (1b), respectively, are rotatably fitted between the holder plates (1d), (1e). Consequently, a vertical intermediate space is provided between the top (1a) and the bottom pulley (1b), between the holder plates. This intermediate space contains the second pulley element (2) which comprises a top (2a) and a bottom (2b) pulley which are rotatably fitted to a common holder element which is situated between the holder plates (1d), (1e) and is movable between these holder plates (1d), (1e) in a vertical direction. In this case, the holder plates (1d), (1e) function as guide means for the second pulley element (2).
The pulleys (2a), (2b) of the second pulley element (2) have a larger diameter than the pulleys (1a), (1b) of the first pulley element (1).
The first pulley element (1) hangs by the top pulley (1a) in the loop which hangs downwards and is formed by a first pulley cord (7) whose ends are connected to a respective hook (3), (4). These hooks (3), (4) cooperating with the first pulley element are referred to as the first hook pair or the first hooks. The expression a first hook is understood to mean one of the hooks of the first hook pair.
The second pulley element (2) hangs by the top pulley (2a) in the loop which hangs downwards and is formed by a second pulley cord (8) whose ends are connected to a respective hook (5), (6). These hooks (5), (6) cooperating with the second pulley element (2) are referred to as the second hook pair or the second hooks. The expression a second hook is understood to mean one of the hooks of the second hook pair.
Furthermore, the shed-forming device also comprises two elongate blades (9), (10) which are arranged next to each other and extend perpendicular to the plane of the drawing. The blades may be driven in order to move up and down in opposite phases with respect to each other. The hooks (3), (4) of the first hook pair are situated within reach of a different blade. The hooks (5), (6) of the second hook pair are also situated within reach of a different blade. Consequently, each blade (9), (10) can carry along one first hook (3), (4) and one second hook (5), (6).
The hooks (3), (4), (5), (6) can thus be moved by a blade (9), (10) between a top position and a bottom position. In the vicinity of the top position of the hooks (3), (4), (5), (6), between the vertical movement trajectories of the blades (9), (10) and their respective associated hooks (3), (5) ; (4), (6), two selection elements (11), (12) are provided one above the other. The selection elements (11), (12) each comprise two electromagnetic coils which are arranged next to each other in the selection element (11), (12), so that a respective hook (3), (4); (5), (6) on opposite sides of the selection element (11), (12) can be deformed to such a degree by the electromagnetic force generated thereby, that this hook hooks onto a respective hooking edge of the selection element and is thus held at the height of this hooking edge and is consequently selected.
The two first hooks (3), (4) may, for example, be selected by the coils of the top selection element (11), while the two second hooks (5), (6) may be selected by the coils of the bottom selection element (12). However, the selection elements (11), (12) and the hooks may also be provided such that each selection element can select, on one hand, a first hook (3), (4) and, on the other hand, a second hook (5), (6).
It should be noted that, in all drawings, the selection elements (11), (12) are diagrammatically represented at a location which is situated above the top position of the hooks. This has only been done for the sake of clarity of the drawings and does not detract from the fact that each hook has to be within reach of a coil and a hooking edge in the vicinity of its top position so that it can be selected. The selection elements are thus actually arranged lower, between the hooks.
Every time a hook (3), (4), (5), (6) is brought in the vicinity of its top position by its blade (9), (10), there is a choice between actuating the associated coil of a selection element (11), (12) in order to select the hook and to hold it in this top position while the blade moves back downwards or not actuating the associated coil, so that the hook is carried along again by the blade in a downwards direction.
As is clearly shown in Figs. 2a, 2b, 2c and 2d, the first pulley element (1) can be brought into a top (T1) position via the first pulley cord (7) by bringing the two first hooks (3), (4) into their top position. By bringing one first hook (3), (4) into its top position and bringing the other first hook (4), (3) into its bottom position, the first pulley element (1) is brought into a bottom position (B1) via the first pulley cord (7).
Analogously, it is possible to bring the second pulley element (2) into a top position (T2) via the second pulley cord (8) by bringing the two second hooks (5), (6) into their top position and to bring the second pulley element (2) into a bottom position (B2) via the pulley cord (8) by bringing one second hook (5), (6) into its top position and the other second hook into its bottom position (6), (5).
The four different combinations of top and bottom positions of the two pulley elements (1), (2) are illustrated in Figs. 2a, 2b, 2c and 2d. In these figures, the heddles (30), (31) and the return springs (32), (33) are not illustrated. However, in this case, these components (30-33) and their connection to the pulley cords (13), (14) are analogous to what is shown in Fig. 1.
In order to transmit the movements of the pulley elements (1), (2) to the heddles (30), (31), the first pulley cord (13) is connected to a fixed point of the device at one end (13a), the pulley cord (13) then runs over the bottom pulley (1b) of the first pulley element (1) and the first pulley cord (13) is finally connected to the first heddle (30) at the other end (13b). The second pulley cord (14) is connected to a fixed point of the device at one end (14a), then runs over the bottom pulley (2b) of the second pulley element (2) and is finally connected to the second heddle (31) at the other end (14b).
If the first pulley element (1) has been brought into its top position (T1) (the situation shown in Figs. 2a and 2c), then the end (13b) connected to the first heddle (30) has been brought to a top height (S1). If the first pulley element (1) has been brought into its bottom position (B1) (the situation shown in Figs. 2b and 2d), then the end (13b) connected to the first heddle (30) has been brought to a bottom height (S2).
If the second pulley element (2) has been brought into its top position (T2) (the situation shown in Figs. 2a and 2b), then the end (14b) connected to the second heddle (31) has been brought to a top height (S1). If the second pulley element (2) has been brought into its bottom position (B2) (the situation shown in Figs. 2c and 2d), then the end (14b) connected to the second heddle (31) has been brought to a bottom height (S2).
By means of such a device, two (groups of) warp threads can be brought to two different heights independently of each other.
Compared to existing jacquard machines, a jacquard machine with two positions provided with such shed-forming devices will have a smaller total footprint or will be able to position a larger number of heddles on the same footprint.
A first embodiment of a shed-forming device with four positions is illustrated in Figs. 3a, 3b, 3c and 3d. Only one pulley cord (15) is provided and cooperates with the two pulley elements (1), (2). Similar to the above-described shed-forming device with two positions, two first hooks (3), (4) are provided which are connected by a pulley cord (7) which supports the first pulley element (1) and two second hooks (5), (6) are provided which are connected by a pulley cord (8) which supports the second pulley element (2). In the same way, the hooks may also be carried along by respective blades (9), (10) which move up and down in opposite phases and may optionally be selected in the vicinity of their top position by a respective electromagnetic coil of a selection element (11), (12) to be held at a fixed height.
By suitably selecting the hooks (3), (4), (5), (6), it is possible to bring the first pulley element (1) to a top position (T1) or a bottom position (B1), as desired, and to bring the second pulley element (2) to its top position (T2) or its bottom position (B2).
The first pulley element (1) comprises two elongate holder plates (1d), (1e) which extend vertically (see also Figs. 5 and 6). In the vicinity of the top and the bottom end of the holder plates, a top pulley (1a) and a bottom pulley (1b), respectively, are rotatably fitted between the holder plates. The first pulley element (1) now also comprises an additional pulley, referred to below as the third pulley (1c), which is rotatably fitted between the holder plates (1d), (1e) at a small intermediate distance above the bottom pulley (1b). The third pulley (1c) has a diameter which is slightly greater than the diameter of the top (1a) and the bottom pulley (1b) of the first pulley element (1).
A vertical intermediate space is provided between the top (1a) pulley and the third pulley (1c) of the first pulley element (1), between the holder plates (1d), (1e). This intermediate space contains the second pulley element (2) which comprises a top (2a) and a bottom pulley (2b) which are rotatably fitted to a common holder element which is situated between the holder plates (1d), (1e) and is movable between these holder plates (1d), (1e) in a vertical direction.
The pulleys (2a), (2b) of the second pulley element (2) have a larger diameter than the third pulley (1c) of the first pulley element (1).
Below the two pulley elements (1), (2), there are also two pulleys (20a), (20b) rotatably fitted one above the other in a common holder (not shown in the figures) which is fitted to a fixed component of the device. Below, these pulleys (20a), (20b) are referred to as the fixed pulleys or the top and the bottom fixed pulley.
The four different combinations of top and bottom positions of the two pulley elements (1), (2) are shown in Figs. 3a, 3b, 3c and 3d. In these figures, the heddles (30), (31) and the return springs (32), (33) are not illustrated. However, these components (30-33) and their connection to the end (15b) of the pulley cord (15) are analogous to that which is illustrated in Fig. 1.
In order to transmit the movements of the pulley elements (1), (2) to the heddles, the pulley cord (15) is connected to a fixed point of the device at one end (15a) and the pulley cord (15) successively runs from that one end (15a) over the bottom pulley (1b) of the first pulley element (1), under the top fixed pulley (20a), over the third pulley (1c) of the first pulley element (1), under the bottom fixed pulley (20b) and over the bottom pulley (2b) of the second pulley element (2), and the pulley cord is finally connected to a heddle at the other end (15b).
Due to the fact that the pulley cord (15) makes a double loop over a fixed pulley and over a pulley of the first pulley element (1), a vertical movement of the first pulley element is doubled. In other words, an upward or a downward movement of the first pulley element over a specific height, with the second pulley element remaining at the same height, results in the heddle also being moved upwards or downwards over double this height.
If the first pulley element (1) has been brought to its top position (T1), while the second pulley element (2) has also been brought to its top position (T2) (see Fig. 3a), then the end (15b) of the pulley cord (15) which is connected to the heddle has been brought to a top height (H1). If the first pulley element (1) has been brought to its top position (T1) while the second pulley element (2) has been brought to its bottom position (B2) (see Fig. 3b), the end (15b) of the pulley cord (15) ends up at a lower, second height (H2).
If the first pulley element (1) is in its bottom position (B1) and the second pulley element (2) is in its top position (T2) (see Fig. 3c), the end (15b) of the pulley cord (15) ends up at an even lower third height (H3).
If the first pulley element (1) is in its bottom position (B1) and the second pulley element (2) is also in its bottom position (B2) (see Fig. 3d), the end (15b) of the pulley cord (15) ends up at an even lower bottom height (H4).
There is in each case approximately the same difference in height between the top height (H1) and the second height (H2) and between the second height (H2) and the third height (H3) and between the third height (H3) and the bottom height (H4).
By means of such a shed-forming device, warp threads may be brought to one of four different heights in successive shed-forming cycles, in each case as desired.
Compared to existing jacquard machines, a jacquard machine with four positions provided with such shed-forming devices will have a smaller total footprint or will be able to position a larger number of heddles on the same footprint. In addition, the shed-forming devices are easier and more compact and more readily fittable than the existing shed-forming devices with four positions.
A second embodiment of a shed-forming device with four positions is shown in Figs. 4a, 4b, 4c and 4d. Two pulley elements (1), (2) are provided which, using the same means (3)-(12) as described above and through a suitable selection of hooks (3), (4), (5), (6) may be brought into a top (T1), (T2) and a bottom position (B1), (B2) independently of each other in each shed-forming cycle, as desired.
The first pulley element (1) comprises two elongate holder plates (1d), (1e) which extend vertically (see also Figs. 5 and 6). In the vicinity of the top and the bottom end of the holder plates, a top pulley (1a) and a bottom pulley (1b), respectively, are rotatably fitted between the holder plates. Between the top (1a) pulley and the bottom pulley (1b), a vertical intermediate space is provided between the holder plates (1d), (1e). This intermediate space contains the second pulley element (2) which comprises three pulleys (2a), (2b), (2c) which are rotatably fitted one above the other to a common holder element which is situated between the holder plates (1d), (1e) and is movable between these holder plates (1d), (1e) in a vertical direction.
The bottom pulley (2c) of the second pulley element (2) has a diameter which is smaller than the two other pulleys (2a), (2b) of the second pulley element (2) and is greater than the diameter of the pulleys of the first pulley element (1).
Below the pulley elements (1), (2), there are also two pulleys (20a), (20b) rotatably fitted one above the other in a common holder (not shown in the figures) which is fitted to a fixed component of the device. These pulleys (20a), (20b) are referred to as the fixed pulleys or the top and the bottom fixed pulley. The top fixed pulley and the bottom pulley (2c) of the second pulley element (2) have approximately the same diameter.
The four different combinations of top and bottom positions of the two pulley elements (1), (2) are shown in Figs. 4a, 4b, 4c and 4d. In these figures, the heddles (30), (31) and the return springs (32), (33) are not illustrated. However, these components (30-33) and their connection to the end (15b) of the pulley cord (15) are analogous to that which is illustrated in Fig. 1.
In order to transmit the movements of the pulley elements (1), (2) to the heddles, the pulley cord (15) is connected to a fixed point of the device at one end (15a) and the pulley cord (15) successively runs from that one end (15a) over the bottom pulley (1b) of the first pulley element (1), under the top fixed pulley (20a), over the bottom pulley (2c) of the second pulley element (2), under the bottom fixed pulley (20b) and over the central pulley (2b) of the second pulley element (2).
Due to the fact that the pulley cord (15) makes a double loop over a fixed pulley and over a pulley of the second pulley element (2), a vertical movement of the second pulley element (2) is doubled. In other words, an upward or a downward movement of the second pulley element (2) over a specific height, with the first pulley element (1) remaining at the same height, results in the heddle also being moved upwards or downwards over double this height.
If the first pulley element (1) has been brought to its top position (T1) while the second pulley element (2) has also been brought to its top position (T2) (see Fig. 4a), then the end (15b) of the pulley cord (15) which is connected to the heddle has been brought to a top height (H1). If the first pulley element (1) is in its bottom position (B1) and the second pulley element (2) is in its top position (T2) (see Fig. 4b), the end (15b) of the pulley cord (15) ends up at a lower, second height (H2).
If the first pulley element (1) has been brought to its top position (T1) and the second pulley element (2) has been brought to its bottom position (B2) (see Fig. 4c), the end (15b) of the pulley cord (15) ends up at an even lower third height (H3).
If the first pulley element (1) is in its bottom position (B1) and the second pulley element (2) is also in its bottom position (B2) (see Fig. 4d), the end (15b) of the pulley cord (15) ends up an even lower bottom height (H4).
There is in each case approximately the same difference in height between the top height (H1) and the second height (H2) and between the second height (H2) and the third height (H3) and between the third height (H3) and the bottom height (H4).
By means of such a shed-forming device, warp threads may be brought to one of four different heights in successive shed-forming cycles, in each case as desired. In addition, the shed-forming devices are easier and more compact and more readily fittable than the existing shed-forming devices with four positions.
Compared to existing jacquard machines, a jacquard machine with four positions provided with such shed-forming devices will have a smaller total footprint or will be able to position a larger number of heddles on the same footprint.
All the above-described embodiments are provided with a first pulley element (1) and a second pulley element (2) which is incorporated in the first pulley element (1), as it were. The first pulley element occupies a specific space (A) and the second pulley element (2) is movable up and down between its top position in a movement space (B) which is situated at least partly inside the space (A) which is occupied by the first pulley element (1). The compact design of these shed-forming devices is thus mainly achieved by the fact that one pulley element (2) is accommodated in the other pulley element (1). The one pulley element (2) moves in a space (B) which is situated at least partly inside the space (A) which is occupied by the other pulley element (1) and the juxtaposed vertical pulley cord parts extend in one vertical plane which coincides with the operating plane of the pulleys and is perpendicular to the direction in which the blades (9), (10) extend (perpendicular to the plane of the drawings).
Fig. 5 shows a first pulley element (1) with a top (1a) and a bottom pulley (1b) in its bottom position (B1) and a second pulley element (2) with a top (2a) and a bottom pulley (2b) in its top position (T1). In Fig. 6, this first pulley element (1) is shown in its top position (T1) and this second pulley element (2) is shown in its bottom position (B2).
Both Fig. 5 and Fig. 6 consist of three figures, a left-hand figure, a middle figure and a right-hand figure. In the left-hand figures, the first pulley element (1) and the associated hooks (3), (4) and the supporting pulley cord (7) are shown separately. In these left-hand figures, the space (A) which the first pulley element (1) occupies is shown most clearly as a beam-shaped space (A) with edges which are indicated as a dash-dotted line. The space (A) which the first pulley element (1) occupies is the smallest possible surrounding beam-shaped space with all sides touching the first pulley element (1), wherein the top side and the bottom side are horizontal, two vertical lateral faces run parallel to the plane in which the blades extend (or are perpendicular to the operating plane of the pulleys) and two other vertical lateral faces are perpendicular to the first-mentioned lateral faces (or are parallel to said operating plane).
In the middle figures, the second pulley element (2) and the associated hooks (5), (6) and the supporting pulley cord (8) are shown separately. In the middle figures, the movement space (B) of the second pulley element (2) is shown most clearly as a beam-shaped space (B) with edges which are indicated as a dash-dotted line.
The movement space (B) of the second pulley element (2) is the smallest possible surrounding beam-shaped space in which the second pulley element (2) can move up and down between its top (T2) and its bottom position (B2). This movement space (B) is delimited at the top by the horizontal plane which touches the top side of the second pulley element (2) when this is in its top position (T2), is delimited at the bottom by the horizontal plane which touches the bottom side of the second pulley element (2) when this is in its bottom position (B2) and is delimited laterally by two vertical lateral faces which run parallel to the plane in which the blades (9), (10) extend (or are perpendicular to the operating plane of the pulleys), and two other vertical lateral faces which are perpendicular to the first-mentioned lateral faces (or are parallel to said operating plane).
In the right-hand figures, the two pulley elements (1), (2) are shown together in the situation where they are accommodated in a shed-forming device according to the invention and function. This situation was described above with reference to Figs. 1, 2a, 2b, 2c and 2d.
As can be seen, the movement space (B) is largely situated inside the space (A) which is occupied by the first pulley element (1). Due to the fact that the pulleys (2a), (2b) of the second pulley element (2) have a larger diameter than the pulleys (1a), (1b) of the first pulley element (1), the movement space (B) is slightly wider than the space (A) which is occupied by the first pulley element (1). Consequently, the movement space (B) is only partly inside the space (A) occupied by the first pulley element (1).
The space (A) occupied by the pulley element (1) can be determined in the same way as well for the embodiment in which the second pulley element (2) comprising two pulleys (2a), (2b) is incorporated in a first pulley element (1) which comprises an additional third pulley (1c) (as illustrated in Figs. 3a, 3b, 3c and 3d). The movement space (B) of the second pulley element (2) is also partly situated inside this occupied space (A).
The movement space (B) for the second pulley element (2) can be determined in the same way as well for the embodiment in which the second pulley element (2) comprises three pulleys (2a), (2b), (2c) one above the other and is incorporated in a first pulley element (1) which only comprises a top (1a) and a bottom pulley (1b) (as illustrated in Figs. 4a, 4b, 4c and 4d). The movement space (B) of the second pulley element (2) is also partly situated inside the space (A) occupied by the first pulley element (1).
As a result thereof, the two pulley elements (1), (2) are united to form a compact unit, while they can still function and move independently of one another.

Claims

Shed-forming device for a weaving machine, comprising:
- a first pulley element (1) and a second pulley element (2),

- lifting and selection means (3)-(12) in order to, in successive shed-forming cycles, bring the first pulley element (1) into a top position (T1) or a bottom position (B1), as desired, and bring the second pulley element (2) into a top position (T2) or a bottom position (B2), as desired, and

- a pulley cord (15) which is connected to a heddle for positioning at least one warp thread on a weaving machine and which cooperates with the first (1) and the second pulley element (2) in such a way that the heddle can be brought to four different heights (H1), (H2), (H3), (H4), depending on the positions (T1), (B1);(T2), (B2) of the two pulley elements (1), (2),
characterized in that, the second pulley element (2) is movable between its top (T2) and its bottom position (B2) in a movement space (B) which is located at least partly within the space (A) occupied by the first pulley element (1), both when the first pulley element (1) has been brought to its top position (T1) and when it has been brought into its bottom position (B1).
Shed-forming device for a weaving machine according to Claim 1, characterized in that the lifting and selection means (3)-(12) comprise a first pair of hooks (3), (4) and a second pair of hooks (5), (6) and are provided to hold each hook (3)-(6) at a first height or bring it to a second height, as desired, in that the first pulley element (1) can be brought to a top (T1) and a bottom (B1) position by the hooks (3), (4) of the first pair, and in that the second pulley element (2) can be brought to a top (T2) and a bottom position (B2) by the hooks (5), (6) of the second pair.
Shed-forming device for a weaving machine according to Claim 1 or 2, characterized in that it comprises a first (20a) and a second fixedly arranged pulley (20b), and in that one end (15a) of the pulley cord (15) is connected to a fixed point and the other end (15b) is connected to the heddle, and the pulley cord successively runs from one end (15a) over a pulley (1b) of the first pulley element (1), under the first fixed pulley (20a), over a pulley (2c) of the second pulley element (2), under the second fixed pulley (20b) and over a pulley (2b) of the second pulley element (2).
Shed-forming device for a weaving machine according to Claim 1 or 2, characterized in that it comprises a first (20a) and a second fixedly arranged pulley (20b), and in that one end (15a) of the pulley cord (15) is connected to a fixed point and the other end (15b) is connected to the heddle, and the pulley cord successively runs from one end (15a) over a pulley (1b) of the first pulley element (1), under the first fixed pulley (20a), over a pulley (1c) of the first pulley element (1), under the second fixed pulley (20b) and over a pulley (2b) of the second pulley element (2).
Shed-forming device for a weaving machine according to Claims 3 or 4 characterized in that a horizontal plane, under the first pulley element (1) and above the fixed point to which one end (15a) of the pulley cord (15) is connected, is crossed at six different locations by the pulley cord (15), and in that these six locations are situated in a line.
Shed-forming device for a weaving machine according to Claim 5, characterized in that said line is in the operating plane of the pulleys or runs parallel to the operating plane of the pulleys.
Shed-forming device for a weaving machine, comprising:
- a first pulley element (1) and a second pulley element (2),

- lifting and selection means (3)-(12) in order to, in successive shed-forming cycles, bring the first pulley element (1) into a top position (T1) or a bottom position (B1), as desired, and bring the second pulley element (2) into a top position (T2) or a bottom position (B2), as desired,

- a first pulley cord (13) and a second pulley cord (14) which are connected to a respective heddle (30), (31) for positioning at least one warp thread on a weaving machine, wherein the first pulley cord (13) cooperates with the first pulley element (1) in such a way that the heddle (30) connected thereto can be brought to two different heights (S 1), (S2), depending on the position of the first pulley element (1), and wherein the second pulley cord (14) cooperates with the second pulley element (2) in such a way that the heddle (31) connected thereto can be brought to two different heights (S1), (S2), depending on the position of the second pulley element (2),
characterized in that the second pulley element (2) is movable between its top (T2) and its bottom position (B2) in a movement space (B) which is located at least partly within the space (A) occupied by the first pulley element (1), both when the first pulley element (1) has been brought to its top position (T1) and when it has been brought into its bottom position (B1).
Shed-forming device for a weaving machine according to Claim 7, characterized in that the lifting and selection means (3)-(12) comprise a first pair of hooks (3), (4) and a second pair of hooks (5), (6) and are provided to hold each hook (3)-(6) at a first height or bring it to a second height, as desired, in that the first pulley element (1) can be brought to a top (T1) and a bottom position (B1) by the hooks (3), (4) of the first pair, and in that the second pulley element (2) can be brought to a top (T2) and a bottom position (B2) by the hooks (5), (6) of the second pair.
Shed-forming device for a weaving machine according to Claim 7 or 8, characterized in that first pulley cord (13) is connected at one end (13a) to a fixed point of the device, runs over a pulley (1b) of the first pulley element (1) and is connected to a first heddle (30) at the other end (13b), and in that the second pulley cord (14) is connected at one end (14a) to a fixed point of the device, runs over a pulley (2b) of the second pulley element (2) and is connected to a second heddle (31) at the other end (14b).
Shed-forming device for a weaving machine according to one of the preceding claims, characterized in that the first pulley element (1) comprises two pulleys (1a), (1b); (1a), (1c) between which a vertical intermediate space is provided, and in that the second pulley element (2), which is at least partly located inside this vertical intermediate space, is movable up and down between its top (T2) and its bottom position (B2).
Shed-forming device for a weaving machine according to one of the preceding claims, characterized in that the first pulley element (1) comprises a guide means (1d), (1e) which is provided to guide the second pulley element (2) during its movements between its top (T2) and its bottom position (B2).
Shed-forming device for a weaving machine according to one of Claims 7 to 11, characterized in that a first horizontal plane, under the first pulley element (1) and above the fixed point to which one end (13a) of the first pulley cord (13) is connected, is crossed at two locations by the first pulley cord (13), in that a second horizontal plane, under the second pulley element (2) and above the fixed point to which one end (14a) of the second pulley cord (14) is connected, is crossed at two locations by the second pulley cord (14), and in that the vertical projection in a third horizontal plane of said two locations on the first horizontal plane and of said two locations on the second horizontal plane is in a line.
Shed-forming device for a weaving machine according to Claim 12, characterized in that said line is in the operating plane of the pulleys or runs parallel to the operating plane of the pulleys.
Shed-forming device for a weaving machine according to one of the preceding claims, characterized in that the lifting and selection means (3)-(12) comprise two first hooks (3), (4) which are provided next to each other at a distance apart and are movable up and down and two second hooks (5), (6) which are provided next to each other at a distance apart and are movable up and down, in that the lifting and selection means (3)-(12) comprise, for each hook (3)-(6), a respective selection means to either select the hook (3)-(6), so that the hook (3), (4), (5), (6) is held at a first height or not to select the hook, as desired, so that the hook is moved to a second height, in that respective first selection means are provided next to each other for the two first hooks (3), (4) in a first selection element (11) between these first hooks (3), (4), in that respective second selection means are provided next to each other for the two second hooks (5), (6) in a second selection element (12) between these second hooks (5), (6), and in that the first selection element (11) and the second selection element (12) are situated one above the other.
Shed-forming device for a weaving machine according to Claim 14, characterized in that one first hook (3) and one second hook (5) are situated on one side of the selection elements (11), (12), and in that the other first hook (4) and the other second hook (6) are situated on the other side of the selection elements (11), (12).