Apparatus for driving loom heald frames

Abstract: The present invention relates to an apparatus for driving a heald frame of a loom, and particularly, it is an object of the present invention to provide an apparatus for driving a loom heald frame using a linear motor having a sufficiently large driving force and being capable of securing a sufficiently long driving stroke. A heald frame 21 is driven vertically along a guide 23 by the driving force of a linear motor 24 transferred through a connecting lever 26. At this moment, by utilizing the principle of a lever and fulcrum, using a connecting lever 26 and the fulcrum 26a, a large driving force is obtained by using a linear motor with a long stroke, or a long stroke necessary to drive the heald frame is obtained by using a linear motor with a large driving force. By adopting such a configuration, the heald frame 21 can be vertically driven by a sufficiently large driving force and a sufficiently long stroke.

Description: Background of the Invention Field of the Invention The present invention relates to an apparatus for driving heald frames of a loom. Description of the Prior Art Conventionally, there is a loom on which a piece of silk cloth is woven by spreading mails by vertically moving a plurality of heald frames with many warps threaded through the mails in each heald frame, inserting a woof through the spread warps in the mails, by inserting a shuttle with the woof attached through the warps, and drawing the inserted woof to the front end using a reed. Generally speaking, two, three or more, and four or more heald frames are normally used in a plain weave loom called a Mihara-kumi loom, a twill weave loom and a satin weave loom, respectively. Simple patterns such as checks, etc. can also be woven by increasing the number of heald frames. For such a vertical driving of a heald frame, it is also proposed, for example, to drive each heald frame using a linear motor as shown in Fig. 1. In the method shown in the drawing, moving elements 12 made of copper or aluminum plate are mounted on the vertical sides of the frames of the heald frame 11, and frame guides 13 are provided to guide these moving elements 12. Stators 15 are mounted at the bottom of grooves 14 in these frame guides 13. The stators 15 are made by stamping out recesses from an electric plate, and a plurality of coils are wound in each recess. A linear motor 16 is composed of the above-mentioned moving elements 12 and stators 15, and the vertical reciprocating movement of the heald frame 11 is controlled by successively providing an excitation current to the plurality of stator coils thereby creating a linear progression of the electro-magnetic fields in the stators 15. The driving control to the linear motor 16 can be corrected when the position of the heald frame 11 is recognized as being outside a predetermined range by an arithmetic circuit 19, based on the main axis angle of the loom detected by the output signal from a loom angle sensor 17 and a base position sensor 18. That is, a linear motor for driving a heald frame is controlled based on the base position detecting signal of the heald frame 11. However, the above-mentioned conventional driving apparatus for a loom heald frame using a linear motor has the following problem. Since the loom heald frame has a rather heavy weight of 7 to 10kgs, a large driving force (propulsive force) is required to drive the heald frame. For this reason, a driving force sufficient to vertically move the heald frame cannot be obtained by a normally used linear motor having a small propulsive force, such as a linear induction motor, linear DC motor, linear synchronous motor, etc. Usually the characteristic feature of these motors is that they have a long driving stroke. On the other hand, there is also a type of linear motor that has a large driving force such as a linear vibration actuator, linear solenoid, laminated piezo-electric element, etc. However, these linear motors cannot sufficiently meet the requirements in the stroke of the heald frame. WO 93 25740 A discloses a generic apparatus for driving loom heald frames. This apparatus comprises a plurality of heald frames aligning next to each other in the direction perpendicular to the loom width, a plurality of driving means spaced in the heald frame alignment direction for moving each of the heald frames independently, and a plurality of converting means for transmitting power of the driving means to the heald frames and reciprocating the heald frames, with one end of each of the converting means being connected to one of the heald frames and the other end being connected to one of the driving means. Summary of the Invention It is an object of the present invention to provide an apparatus for driving a heald frame having an improved driving force (propulsive force) and/or an improved driving stroke. The problem is solved by an apparatus according to claim 1. The invention is further developed by the subclaims. Brief Description of the Drawings Fig. 1 shows a conventional example of an apparatus for driving a heald frame using a linear motor. Fig. 2A is a front view of the driving apparatus of a loom heald frame in the first embodiment of the invention. Fig. 2B is a side view of the driving apparatus of a loom heald frame in the first embodiment of the invention. Fig. 3 is a top view of the driving apparatus of a loom heald frame in the first embodiment of the invention. Fig. 4 is a side view of the driving apparatus of a loom heald frame in the first embodiment of the invention. Fig. 5 explains the second embodiment of this invention. Description of the Preferred Embodiments The embodiments of this invention are described below with reference to the drawings. Fig. 2A and Fig. 2B are a front view and a side view, respectively, of the driving apparatus of a loom heald frame in the first embodiment of this invention. In Figs. 2A and 2B the heald frame 21 is composed of four frames as shown in the drawings, and each heald frame 21 is supported by a guide 23 provided in a guide frame 22. Each heald frame 21 is driven by a linear motor 24, and the driving control of the linear motor 24 varies depending on the kind of the linear motor. For the transference of the driving force (propulsive force) from the linear motor to the heald frame, a connecting lever 26 is used. That is, one end of the connecting lever 26 is connected to the lower end of the side stay 27 of each heald frame in a rotatable state, and the other end of the connecting lever 26 is connected to the driving axis 24' of the linear motor in a rotatable state. This connecting lever 26 can be freely rotated about a fulcrum 26a at its center, and the driving axis 24' of the linear motor, the connecting lever 26 and the heald frame 21 are so structured that the principle of a lever and a fulcrum may be utilized. Fig. 3 is a top view of the above-mentioned driving apparatus. Particularly, as seen from Fig. 3, each heald frame is provided with a linear motor 24 on each side of the frame, and the two linear motors for each heald frame are connected to the left and right side stays 27 of each heald frame. That is, any of the four heald frames 21 are provided with two linear motors 24 connected to the left and right sides. The four heald frames 21 are so structured that the width of each frame may become narrower as the heald frames 21 go away from the linear motors 24, and are so arranged that the connecting levers 26 mounted on each side of each of the heald frames 21 may not interfere with each other. Since the connecting levers 26 corresponding to the four heald frames 21 have the same length, each of the linear motors 24 are arranged in suitable positions, one staggered behind the other successively. For the linear motor 24 of this embodiment a linear induction motor is used. This linear induction motor is a linear motor with a long stroke and a small propulsive force. A coil is formed as the stator of the primary side of the linear motor 24, for example, to generate eddy currents in the moving element of the secondary side, formed of a magnetic material, to drive the moving element in the direction of the progressive magnetic field, by passing an electric current through the coil. This moving element is the above-mentioned driving axis 24', and by passing a current through the coil, the driving axis is driven in the direction of the progressive magnetic field, shown by the arrows a and b in Fig. 4. The processing operation of the driving apparatus of a loom heald frame having the above-mentioned configuration is described below. First, a loom is supplied with power to make the loom enter a driving state, and the heald frame 21 is vertically driven by controlling the supply of current to the primary side coil of the linear motor 24. Specifically, the driving axis 24' is driven upward by passing a current through the coil of the linear motor 24 to generate a progressive magnetic field in the direction of the arrow a as shown in Fig. 4, and correspondingly the heald frame 21 is shifted downward (in the direction of the arrow A) by the driving action of the connecting lever 26 (about the fulcrum 26a). Then, conversely, the driving axis 24' is driven downward by generating a progressive magnetic field in the direction of the arrow b as shown in Fig. 4, and the heald frame 21 is shifted upward (in the direction of the arrow B) through the action of the connecting lever 26. Therefore, by repeating the above-mentioned processes the heald frame is vertically driven, and at this moment, the driving force for driving the heald frame is sufficiently large. For example, if a joint between the connecting lever 26 and a side stay 27 (of the heald frame 21), and a joint between the driving axis 24' of the linear motor 24 and the connecting lever 26 are assumed as 28 and 29, respectively, the driving force for driving the heald frame 21 against the driving force of the linear motor 24 is proportional to the ratio of the length (L2) of the lever from the fulcrum 26a to the joint 29, to the length (L1) of the lever from the fulcrum 26a to the joint 28. Therefore, for example, if L1/L2 is assumed to be set to "1/10", the driving force of the linear motor is multiplied tenfold, and the heald frame 21 can be alternately driven in the directions of the arrows A and B by a driving force ten times the original driving force of the linear motor 24. Therefore, for example, even if a linear motor with a rather small driving force such as a linear induction motor is used, a large driving force can be obtained, and the heald frame can be vertically driven by a sufficiently large driving force. Although, in the above-mentioned embodiment, a linear induction motor is used for the linear motor 24, another linear motor with a long stroke and a small propulsive force, for example, such as a linear DC motor, linear synchronous motor, linear pulse motor, etc. can also be used. Further, although in the above-mentioned embodiment L1/L2 is set to "1/10", L1/L2 can be freely set depending on the propulsive force of the linear motor 24 and the weight and required stroke length of the heald frame 21. Next, the second embodiment of this invention is described below. Although Fig.5 explains the driving apparatus of a loom heald frame of this embodiment, the drawing shows a configuration in the case where the driving apparatus drives one heald frame, and the heald frame is provided with two linear motors 30 on its left and right sides. A heald frame assembly is composed of four frames, and each heald frame is provided with two linear motors. Although the configuration of the heald frame 21, guide frame 22, guide 23 and side stay 27 to be used in this embodiment is the same as the configuration shown in the above-mentioned Figs.2 and 3, the structure of the connecting lever 26, that is, the position of the fulcrum 26a of the connecting lever 26 is different. The kind of linear motor to be used is also different. Specifically, the fulcrum 26a of the connecting lever 26 is so structured that the length (L1) from the fulcrum 26a to the joint 28 may be longer than the length (L2) from the fulcrum 26a to the joint 29. That is, the fulcrum 26a is so located that L1 > L2. For the linear motor, a linear motor 30 with a large propulsive force and a short stroke is used. For such a linear motor 30, for example, a linear vibration actuator is used in this embodiment. This linear vibration actuator has a stator coil that is supplied with an alternating voltage of a sine wave or rectangular wave form, to make the driving axis 30' perform reciprocating motion with a large propulsive force at certain intervals. Next, the operation of the second embodiment with the above-mentioned configuration is described below. First, the driving axis 30' is driven in the direction of the arrow a (upward) by supplying a voltage to the coil of the linear motor 30, and the heald frame 21 is shifted downward (in the direction of the arrow A) through the action of the connecting lever 26 (about the fulcrum 26a). Then, conversely, the driving axis 30' is driven in the direction of the arrow b (downward), and the heald frame 21 is shifted upward (in the direction of the arrow B ) through the action of the connecting lever 26, and by repeating the above-mentioned processes successively, the heald frame 21 is vertically driven. At this moment, since the driving is performed by a linear vibration actuator originally with a large propulsive force, the driving force for driving the heald frame 21 is sufficiently large. The stroke of the heald frame can also be made sufficiently long according to the mechanical advantage of the connecting lever 26. For example, if it is assumed that the driving stroke of the linear motor 30 is ±5mm, and if it is desired that a stroke of ±50mm of the heald frame 21 is obtained, the heald frame 21 can be vertically driven with a stroke ten times the stroke of the linear motor 30, by setting the ratio (L1/L2) of the length (L1) from the fulcrum 26a to the joint 28 to the length (L2) from the fulcrum 26a to the joint 29, to "10/1". At this moment, although the driving force of the linear motor 30 conveyed to the heald frame is reduced to 1/10, the driving force is still sufficiently large to drive the heald frame 21 since the original driving force of the linear motor 30 is large. According to this embodiment, even if a linear motor with a large propulsive force and a short stroke such as a linear vibration actuator is used, the heald frame can be driven with a sufficiently long stroke. Although, in the above-mentioned embodiment, a linear vibration actuator is used for the linear motor 30, another linear motor with a large propulsive force and a short stroke, for example, such as a linear solenoid, laminated piezo-electric element, etc. can also be used. Further, although in the above-mentioned embodiment L1/L2 is set to "10/1", L1/L2 can be freely set depending on the propulsive force of the linear motor 30 and the weight and required stroke length of the heald frame. As described above, according to the present invention, even a heavy heald frame can be driven by linear motors with a sufficiently large driving force and a sufficiently long stroke. The great merit that a heald frame can be driven by a sufficiently large driving force and a sufficiently long stroke using a simple configuration can therefore be realized. The present invention relates to an apparatus for driving a heald frame of a loom, and particularly, it is an object of the present invention to provide an apparatus for driving a loom heald frame using a linear motor having a sufficiently large driving force and being capable of securing a sufficiently long driving stroke. A heald frame 21 is driven vertically along a guide 23 by the driving force of a linear motor 24 transferred through a connecting lever 26. At this moment, by utilizing the principle of a lever and fulcrum, using a connecting lever 26 and the fulcrum 26a, a large driving force is obtained by using a linear motor with a long stroke, or a long stroke necessary to drive the heald frame is obtained by using a linear motor with a large driving force. By adopting such a configuration, the heald frame 21 can be vertically driven by a sufficiently large driving force and a sufficiently long stroke.

Claims: An apparatus for driving loom heald frames, comprising: a plurality of heald frames (21) aligning next to each other in the direction perpendicular to the loom width, a plurality of driving means (24, 24'; 30, 30') being linear motors staggered one behind the other in the heald frame alignment direction for moving each of the heald frames (21) independently, and a plurality of converting means (26, 26a, 28, 29) comprising connecting levers (26) for transmitting power of the driving means (24, 24'; 30, 30') to the heald frames (21) and reciprocating the heald frames (21), with one end of each of the connecting levers (26) being connected to one stay (27) of one of the heald frames (21) and the other end being connected to one of the driving means (24, 24'; 30, 30'), characterized in that: the connecting levers (26) are perpendicular to the loom width direction, and the converting means (26, 26a, 28, 29) in particular are spaced one after another in the loom width direction, so that the connecting levers (26) may not interfere with each other. An apparatus for driving loom heald frames according to claim 1, wherein said converting means (26, 26a, 28, 29) are positioned within the width for housing the healds. An apparatus for driving loom heald frames according to claim 1, wherein said driving means (24, 24'; 30, 30') are positioned so as to be aligned in both the heald frame alignment direction and the heald width direction.

Inventors: UEMATSU TATSUYA, UEMATSU, TATSUYA
Applicants: TOYOTA JIDOSHOKKI KK, KABUSHIKI KAISHA TOYOTA JIDOSHOKKI
Application year: 1998
Main classification: D03C5
IPC codes: D03C5, D03C13, H02K41, D03C1