EP2313544B1

EP2313544B1 - Selection and guiding bodies for hooks in a jacquard machine

Info

Publication number: EP2313544B1
Application number: EP09756558.4A
Authority: EP
Inventors: Geert Maes; Bram Vanderjeugt
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-06-25
Filing date: 2009-06-25
Publication date: 2013-11-13
Anticipated expiration: 2029-06-25
Also published as: WO2009156835A3; CN102099518B; BE1018197A3; WO2009156835A2; CN102099518A; EP2313544A2

Description

This invention relates to a hook selection device for a shed forming device for a weaving machine, more specifically a Jacquard machine, comprising a number of guiding bodies placed next to one another and a number of hooks which can be moved up and down by a lifting means between the guiding bodies and, for each hook, a selection body with which the hook can be selected in order to be held by a holding element at a selection height, each selection body comprising one or more positioning lips in order to position the selection body between the guiding bodies, and each guiding body comprising two legs which have a free end between which a PCB can be mounted as a support of one or more selection bodies.
During weaving on a weaving machine, one or more weft threads are inserted, in successive operating cycles of the weaving machine, into a shed between warp yarns. Weft threads are inserted in each case at well-defined weft insertion levels. During weaving, the various warp yarns should be brought, in each operating cycle, into a predefined position with respect to each weft insertion level in order to obtain the desired fabric. Devices allowing warp yarns to be brought automatically into these predefined positions during weaving on a weaving machine are generally known and are referred to as shed forming devices.
Thus, Jacquard machines are known with which the warp yarns can be positioned individually or in groups during weaving on a weaving machine. The warp yarns each move through a heddle eyelet which forms part of a heddle which in one direction is drawn downward by a retracting spring and in the other direction is connected to one or more hooks of the Jacquard device via a harness cord and tackle system, so that the hook can move the warp yam upward counter to the force of the retracting spring and the tension of the warp yarn.
The Jacquard device is provided with two sets of knives which can move up and down in phase opposition and with selection elements in a selection body with which it is possible to choose, by activating or not activating these selection elements, which hooks move or do not move upward along with a knife and which hooks move or do not move downward along with a knife. During this movement, the hook is guided between a selection body and a guiding body. The coupling or non-coupling to the rising and falling knife is implemented by employing actuators, usually solenoids, as the selection element. These are made of a magnetizable material around which conductive windings are provided which, when a current is passed through the windings, magnetize the material so that it will attract or repel the hook in order to bring said hook outside the range of the rising and falling knife and to suspend it from a holding element.
The overall entity formed by the above-mentioned elements (heddle - retracting spring - harness cord - tackle - hook - selection body - guiding body) is multiplely present in a Jacquard machine (for example up to 14,000 times in one Jacquard device) and these elements are, during the production of woven materials, stressed intensively (up to 1,200 times/minute) so that all these elements may be subject to wear and malfunction.
Systems are known, as described in EP 214075 , wherein several of these elements are multiplely assembled in a common holder or cartridge, as a result of which they can be incorporated into a package and exchanged. This allows components to be changed over rapidly, but also means that in each case all these elements have to be exchanged en masse whenever (in many cases) just one of these elements is defective. This therefore also greatly increases the maintenance and operating costs of the device.
Other Jacquard devices, as described in EP 0 188 074 , are constructed in such a way that each of the various aforementioned elements can be replaced separately, so that, in contrast to the above-described method with the common holder or cartridge, the repair costs can be kept right down. In the embodiments as described in EP 0 188 074 , i.e. including in Jacquard devices sold by the applicant under the trade name BONAS® for the types LJ, ZJ, MJ, PTX, PTR, it is conventional for a multiplicity of selection bodies to be constructed on a PCB (printed circuit board) which can be inserted from above into the Jacquard device in order in this way to form a sturdy and stable entity. The solenoids, which are mounted on the aforementioned PCB, are in this case each integrated into a holder (plastics material body). In the Jacquard device, separating plates, on which the guiding bodies for the hooks are mounted, are arranged between various rows of selection bodies and tackle systems. For this purpose, the guiding bodies are embodied as a base support for the holder of the selection element on the PCB.
Toward their upper side, the guiding bodies are provided with two upright legs each displaying in their cross section a T-shape consisting of an end face and a central frame. The central frame can in this case be partially hollowed out. Between the base of the central frames of the T-shape of the cross sections of the two legs of a hook guiding body is an intermediate space between which the PCB, comprising selection elements and their supports, can be introduced. A hook is guided in its rising and falling movement between, on the one hand, two halves of end faces of the T-shaped cross section of legs of hook guiding bodies lying next to one another and, on the other hand, the side edge of the selection body (holder of a selection element).
In view of the length of the supports of the selection elements, the length of the upright legs of the guiding bodies is considerable.
In order to be able to fulfil in a reliable manner their function as a guide for the movement of the hooks, these two upright legs should maintain their position and shape as well as possible. Bending of these legs leads to a deviation of the path of the hook, as a result of which the reliability of the selection of the hook by the selection element (for example the solenoid) is liable to suffer because the hook is located, during the attracting or repelling by the selection element, too far away to react as desired.
It is known therefore to provide the selection bodies, toward the upper side of their side edge, with a recess so that positioning lips are formed wherein the end face of the T-shape of the end of at least one leg of a hook guiding body engages. In this way, after mounting of the PCB comprising selection bodies, the selection body forms, together with the legs of the guiding body of the hook, a closed structure, as a result of which the deformations of the legs of this guiding body are restricted.
When operating at high speed, inter alia the heating within the Jacquard device can be of such a nature that the upright legs of the guiding bodies do still deform in such a way that good guidance of the hook in its rising and falling movement is liable to suffer and selection problems consequently arise. The term "selection problems" refers to the fact that when, for example, the solenoid is intended to attract the hook, this does not take place, despite the fact that a current is passed through the windings of the solenoid.
The object of the invention is to find a solution in order to reduce the risk of the aforementioned selection problems occurring.
The object of the invention is achieved by providing a hook selection device for a shed forming device for a weaving machine, comprising a number of guiding bodies placed next to one another and a number of hooks which can be moved up and down by a lifting means between the guiding bodies and, for each hook, a selection body with which the hook can be selected in order to be held by a holding element at a selection height, each selection body comprising one or more positioning lips in order to position the selection body between the guiding bodies, and each guiding body comprising two legs which are placed at an intermediate distance from each other and have a free end between which a PCB can be mounted as a support of one or more selection bodies, and wherein said free ends are provided to be engaged in the positioning lips of the selection body, the selection body further comprising a locking element which is provided to restrict, when mounted, the increase of the aforementioned intermediate distance between the legs, in a horizontal direction perpendicularly to the PCB. Preferably, the locking element is provided to restrict, when mounted, the increase of the aforementioned intermediate distance between the legs, in a horizontal direction perpendicularly to the PCB. The presence of a selection body embodied in this way ensures a decrease in the number of selection problems.
In a preferred embodiment of the hook selection device according to the invention, at least one leg of the guiding body comprises a restraining element which is provided to interact with the locking element.
In a more preferable embodiment of the hook selection device, the restraining element extends along the longitudinal direction of the leg.
In a particular embodiment of the hook selection device according to the invention, the restraining element is located substantially in the centre of the length of the leg. More particularly, the restraining element is embodied as a protuberance.
In a referred embodiment of the hook selection device according to the invention, the selection body comprises at least a first and second locking element in order to restrict the movement of the first and second leg respectively of the guiding body perpendicularly to the PCB in a horizontal direction in which the aforementioned intermediate distance between the first and second leg increases.
The horizontal movement perpendicularly to the PCB wherein aforementioned intermediate distance between the legs increases (becomes lager) or decreases (becomes smaller) has to be understood as the movement of the legs in a direction away from the PCB and toward the PCB respectively. Embodying the assembly in accordance with this invention restricts these movements.
In a more preferable embodiment of the hook selection device, the selection body comprises a solenoid. A solenoid is a selection element which has electromagnetic coils and is provided to select a hook.
Finally, this invention also relates to a Jacquard machine or a weaving machine provided with one or more hook selection devices according to the invention.
The invention will now be commented on in greater depth based on the subsequent detailed description of a part of a preferred device according to this invention and of the operation of this device. This description is intended merely to provide a clarificatory example and may thus in no way be interpreted as a restriction on of the scope of the invention or of the patent rights sought in the claims.
This description refers by means of reference numerals to the appended figures, wherein:

Figure 1 : shows a combination of the legs of a hook guiding body and a selection body according to the prior art;
Figure 2 : shows a combination of the legs of a hook guiding body and a selection body according to the invention;
Figure 3 : is an illustration of a number of guiding bodies which are placed next to one another and each have two legs which are placed at an intermediate distance from each other and have a free end between which a PCB is mounted as the support of one or more selection bodies;
Figure 4 : is a detailed illustration of the assembly shown in Figure 3 , wherein the positioning of the selection bodies with respect to the guiding bodies is clarified; and
Figure 5 : is a perspective illustration of a guiding body.

The reference numerals refer in this case to the following components:

1: leg of the (hook) guiding body;
1': leg of the adjacent (hook) guiding body;
2: selection body (2' and 2" for the adjacent selection bodies);
3: side edge of the selection body;
4: T-shaped cross section of the leg of the guiding body;
5: central frame of T-shaped cross section of the leg;
6: end face of T-shaped cross section of the leg;
7: hook;
8: restraining element (protuberance) on the leg of the guiding body;
9: locking element (protuberance) on the selection body;
10: T-shaped cross section of leg on its end;
11: positioning lips in the selection body wherein 10 engages during mounting of the selection bodies between the guiding bodies;
12: PCB (printed circuit board) on supporting plate (13).

The hook selection device for a shed forming device for a weaving machine according to this invention comprises a number of guiding bodies (1; 1'; 1"; 1"') placed next to one another and a number of hooks (7) which can be moved up and down by lifting means, from a set of lifting means moving up and down in phase opposition, between the guiding bodies and, for each hook (7), a selection body (2; 2'; 2") which is provided at two opposing sides (3) (side edges) for guiding a hook (7) moving up and down and with which (via a solenoid) this hook (7) can be selected in order to be held by a holding element at a selection height.
Furthermore, each selection body (2) comprises one or more positioning lips (11) in order to position the selection body (2) between the guiding bodies, and each guiding body comprises, as may be seen from Figure 5, two legs (1) which are placed at an intermediate distance (A) from each other and have a free end between which a PCB (as shown in Figure 3) can be mounted as the support of one or more selection bodies (2). It should be noted that the selection bodies are connected to the PCB (12) via a supporting plate (13); a supporting plate (13) is a plate with an opening in the centre between which the selection bodies sit; Figures 3 and 4 show this supporting plate in cross section. In the appended figures, the legs of a first guiding body are denoted by reference numeral 1 and the legs of a second adjacent guiding body are denoted by reference numeral 1'. The legs of further (for example third, fourth, etc.) guiding bodies are denoted by 1", 1'", etc.
The selection body (2) encloses with the positioning lips (11) the end of the legs (1) of the guiding body, as a result of which, when mounted, a closed entity is formed and as a result of which these legs (1) are prevented from deforming in their end.
Each leg (1) displays a T-shaped cross section consisting of a central frame (5) which extends between adjacent selection bodies (2) and an end face (6) which extends at both sides of the central frame (5) in order at least partially to guide, at each side of the central frame (5), a hook (7) during its movement between the side edge (3) of the selection body (2) and the aforementioned end face (6).
The hooks (7) are thin metal flexible hooks which are made of ferromagnetic material and in a known manner form part of the shed forming device which can bring a Jacquard heddle in a controlled manner to a number of different levels by means of tackle cords (not shown in the figures) and tackle elements interacting therewith. These various levels are reached by selecting or not selecting the hooks (7) pertaining to a shed forming device of this type. The hooks (7) are provided on top with a window opening with which they can be hooked to a holding element.
When operating at high speed, inter alia the heating within the Jacquard device can be of such a nature that the upright legs (1) (1') of the guiding bodies do still deform, despite the fact that they are held in their end in the positioning lips (11) of the selection body (2), in such a way that good guidance of the hook (7) in its rising and falling movement is liable to suffer and selection problems consequently arise. In order to reduce the selection problems, the selection body (2) further comprises at least one locking element (9) which is provided to restrict, when mounted, the movement of a leg (1) of the guiding body in the horizontal direction perpendicularly to the PCB. Since the PCB comprising selection bodies (2) is slid between the guiding bodies, there remains at all times a certain degree of mounting play, as a result of which the movement of the leg (1) of the guiding body is above all restricted but is not necessarily avoided altogether.
A selection body (2) is positioned between two guiding bodies lying next to each other, so that each selection body (2) usually comprises a first and second locking element (9) for the first and second leg (1) respectively of one guiding body and furthermore comprises a first and second locking element (9) for the first and second leg (1) respectively of the other guiding body. Thus, at least four locking elements (9) are usually provided for each selection body. The locking element is for example embodied as a protuberance which preferably displays a side face running parallel to the side face of the selection body (2).
Furthermore, and as shown inter alia in Figure 5, at least one leg (1) of the guiding body is provided with a restraining element (8), also in the form of a protuberance (perpendicularly to the central frame of the T-shaped cross section), which is provided to interact, after mounting of the printed circuit board (PCB) (12) between the aforementioned legs (1) of the guiding body, with the corresponding locking element (9). In this way, the locking element (9) will enter substantially into contact with the restraining element (8) and the side face of the locking element (9) is located between the restraining element (8) and the end face (6) of the leg (1) in question. Usually, at least four restraining elements (8) are provided for each guiding body.
Preferably, the restraining element (8) has a limited length in the longitudinal direction of the leg (1) (vertical direction in the Jacquard) and it is located substantially in the centre of the length of the leg. This is the position where the diverging of the leg (1) of the guiding body can be most reduced at a specific play.
One or more locking elements (9) provided on the selection body (2) can also be embodied as two protuberances which are positioned at an intermediate distance from and parallel to each other and are placed, during mounting of the selection body between the guiding bodies, around the corresponding restraining element (8) (protuberance) on the leg (1) in question of the guiding body. This locks even more securely the position of the leg (1) in question of the guiding body and restricts the movement of the legs (1) perpendicularly to the PCB in a horizontal direction in which the aforementioned intermediate distance (A) between the legs becomes smaller (decreases), and ensures as a result good guidance of the hook (7) in its guiding channel.
In another embodiment, one or more restraining elements (8) provided on the guiding body can be embodied as two protuberances which are positioned at an intermediate distance from and parallel to each other and are placed, during mounting of the selection body (2) between the guiding bodies, around the corresponding locking element (9) (protuberance) on the selection body (2). This also locks more securely the position of the leg of the guiding body and ensures as a result good guidance of the hook in its guiding channel.
In order to avoid confusion concerning the direction wherein the locking element (9) and restraining elements (8) are provided, the following should be borne in mind:

the hooks (7) move up and down in the vertical direction;
the guiding bodies for the hooks (7) therefore also extend vertically; the legs (1) of the guiding bodies are arranged vertically;
the guiding bodies are arranged next to one another on a separating plate so that their recess forms between the legs (1) a slot which extends in the longitudinal direction of the separating plate so that the PCB comprising selection bodies (2) can also be inserted along its longitudinal direction via the slots of various guiding bodies positioned next to one another on the same separating plate;
this longitudinal direction (direction of the slot, which corresponds during mounting to the longitudinal direction of the guiding plate) is also the direction wherein the restraining elements (8) protrude from the guiding body;
those protuberances which form the locking element (9) and the restraining element (8) respectively extend, in turn, in the vertical direction, i.e. the direction wherein the PCB comprising the selection bodies (2) is slid between the guiding bodies;
the movement of the legs (1) of the guiding body, which movement is to be prevented/restricted, is a movement in the horizontal direction perpendicularly to the PCB and to the separating plate. It is also that movement which increases or reduces in size the intermediate distance of the legs of the same guiding body.

The locking so as to prevent movement thus takes place by providing a protuberance (restraining element (8)) on the leg (1) of the guiding body which, during mounting of the PCB comprising the selection body (2), rests substantially against the wall of one protuberance (locking element (9)) on the selection body (2).
In principle, there are variants wherein either the leg (1) of the guiding body or the selection body (2) is provided with two protuberances which are positioned next to each other and actually form, as it were, a recess, between which the protuberance in question is positioned on the other element (selection body or guiding body).
Since, in the operating state, movement of the leg toward the PCB is, over the majority of the height of the leg (1) of the guiding body, prevented by the presence of the selection body (2), the locking according to the invention should take place principally so as to prevent movement of the leg of the guiding body away from the PCB. To be absolutely clear, this is the movement which would increase the size of the intermediate distance (A).
Therefore, it may however also be sufficient for there to be present on both elements (leg (1) of the guiding body and selection body) in each case one protuberance (8; 9), which protuberances, by way of their interaction, prevent or restrict the possibility for movement of the leg (1) in the direction away from the PCB.

Claims

Hook selection device for a shed forming device for a weaving machine, comprising a number of guiding bodies placed next to one another and a number of hooks (7) which can be moved up and down by a lifting means between the guiding bodies and, for each hook (7), a selection body (2) with which the hook (7) can be selected in order to be held by a holding element at a selection height, each selection body (2) comprising one or more positioning lips (11) in order to position the selection body (2) between the guiding bodies, and each guiding body comprising two legs (1) which are placed at an intermediate distance (A) from each other and have a free end between which a PCB (12) can be mounted as a support of one or more selection bodies (2), and wherein said free ends are provided to be engaged in the positioning lips (11) of the selection body (2), characterized in that the selection body (2) further comprises a locking element (9) which is provided to restrict, when mounted, the increase of the aforementioned intermediate distance (A) between the legs (1), in a horizontal direction perpendicularly to the PCB.
Hook selection device according to Claim 1, characterized in that at least one leg (1) of the guiding body comprises a restraining element (8) which is provided to interact with the locking element.
Hook selection device according to Claim 2, characterized in that the restraining element (8) extends along the longitudinal direction of the leg (1).
Hook selection device according to Claim 2 or 3, characterized in that the restraining element (8) is located substantially in the centre of the length of the leg.
Hook selection device according to one of Claims 2 to 4 inclusive, characterized in that the restraining element (8) is embodied as a protuberance.
Hook selection device according to one of Claims 1 to 5 inclusive, characterized in that the selection body (2) comprises at least a first and second locking element in order to restrict the movement of the first and second leg respectively of the guiding body perpendicularly to the PCB in a horizontal direction in which the aforementioned intermediate distance (A) between the first and second leg increases.
Hook selection device according to one of Claims 1 to 6 inclusive, characterized in that the selection body (2) comprises a solenoid.
Jacquard machine provided with a hook selection device according to one of Claims 1 to 7 inclusive.