Abstract:
Dobby for a weaving loom in which control of the operative and non-operative positions of retaining hooks or hook arms which are engaged with and disengaged from hooks of heald frame-driving levers to actuate desired heald frame is electrically performed through solenoids corresponding to the respective levers, which are actuated by an electronic control system having a micro-computer.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a dobby, especially a device for controlling a retaining hook. 
     Ordinarily, a dobby card or peg is used for controlling the position of a retaining hook for determining whether or not a movable hook on a double lift balanced lever swung by a bar is engaged with the retaining hook. More specifically, a card or peg for controlling a retaining hook of a dobby is prepared based on a weave texture and the card or peg is attached to the dobby to effect the control of the retaining hook. 
     It is disclosed in U.S. Pat. Nos. 3,285,291, 3,884,273 and 4,182,380 that selective displacement of hooks or levers can be accomplished by means of electromagnets. In these known patents, however, dobby cards or pattern pegs are used. 
     SUMMARY OF THE INVENTION 
     The present invention is to provide a novel dobby in which a retaining hook is controlled by electric signals without using the above-mentioned cards or pegs. 
     According to the present invention, control of the operative and non-operative positions of retaining hooks or hook arms which are engaged with and disengaged from hooks of heald frame-driving levers to actuate desired heald frame motion is electrically performed through solenoids corresponding to the respective levers, which are actuated by an electronic control system having a micro-computer. Accordingly, a mechanical weave texture instructing mechanism arranged in the conventional dobbies, such as a dobby card or pattern peg, need not be used. In the conventional dobbies, in the case where the repetition weft number in the length direction of a weave is large, a very long dobby card is necessary and a special member such as a card guide should be disposed. In the present invention, such dobby card or card guide need not be used at all. 
     Furthermore, if storing elements (ROM) having weave data stored therein are prepared and an appropriate storing element is selected and used, a desired dobby texture can easily be obtained. Moreover, there can be adopted a modification in which standard textures are stored in advance and desired weave data are promptly read out according to instructions of memory addresses without exchange of storing elements. 
     Still further, such operations as pick-finding and levelling operations can be performed very easily and assuredly, and mechanical parts necessary for performing these operations mechanically need not be disposed at all. Accordingly, the apparatus can be made compact and the operation efficiency can be increased. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view diagrammatically illustrating the main structure of an embodiment of the present invention which is applied to a double lift balanced lever dobby; 
     FIG. 2 is a view diagrammatically illustrating the structure of one embodiment of the apparatus of the present invention; 
     FIG. 3 is a view diagrammatically illustrating the structure of another embodiment of the apparatus of the present invention; and 
     FIG. 4 is a view diagrammatically illustrating the structure of still another embodiment of the apparatus of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described in detail with reference to embodiments illustrated in the accompanying drawings. 
     FIG. 1 is a view diagrammatically illustrating the structure of a double lift balanced lever type dobby. Retaining hooks 2a and 2b are pivoted at points 3a and 3b on levers 1a and 1b swung by a control device described hereinafter, and the retaining hooks 2a and 2b are urged to the levers 1a and 1b by springs 4a and 4b. The intermediate portion of a balanced lever 7 is pivoted at the position 8 on the top end of a lever 6 supported on a stationary shaft 5, and hooks 9a and 9b to be engaged with and disengaged from the retaining hooks are pivoted on both ends of the balanced lever 7. By engaging the hooks 9a and 9b with the retaining hooks 2a and 2b, respectively, by bars 11a and 11b reciprocatively moving in directions of arrows 10a and 10b co-operatively with a loom, the lever 6 is turned by a certain angle in the clockwise direction with the shaft 5 being as the center, and a jack lever 12 is pulled rightward and a wire cable 13 connected to the jack lever 12 is pulled, whereby a heald frame (not shown) connected to the top end of the wire cable is raised or lowered to effect the shedding operation of warp threads. 
     FIG. 2 illustrates an embodiment of the control device for controlling the retaining hooks 2a and 2b to the operative and non-operative positions. 
     A cam 14 which rotates synchronously with the rotation of a crank shaft of a dobby (not shown) is pivoted on a perpendicular bisector of the line connecting the centers of the pivoting shafts 3a and 3b of the retaining hooks 2a and 2b.  Even numbers of peaks 15 and troughs 16 (eight peaks and eight troughs in the drawings) are formed on the cam face of the cam 14, and cam rollers 18a and 18b of paired locking levers 17a and 17b are pressed to the cam face by a spring 19 so that with rotation of the cam 14, the locking levers 17a and 17b are always oscillated with shafts 20a and 20b being as the centers. The cam rollers 18a and 18b are arranged on the locking levers 17a and 17b so that the vertical positions of the cam rollers 18a and 18b to the cam 14 are deviated by 180° from each other. A pair of catching levers 22a and 22b provided with hooks 21a and 21b are pivoted at points 23a and 23b in the vicinity of the top ends of the locking levers 17a and 17b, and these catching levers 22a and 22b are urged to the positions not engaged with the top ends of the locking levers 17a and 17b by means of a spring 24 and one ends 26a and 26b of the levers 22a and 22b are caused to abut against a stopper 25, whereby the levers 22a and 22b are locked at non-engaging positions. Small solenoids 27a and 27b or air cylinders are arranged in the side portions of the catching levers 22a and 22b so that the top ends of solenoid rods 32a and 32b abut against the catching levers 22a and 22b. When the solenoids are actuated, the catching levers 22a and 22b are slightly displaced with the shafts 23a and 23b being as the centers and become engaged with the top ends of the locking levers 17a and 17b. 
     A pair of push levers 28a and 28b having the locking levers 17a and 17b pivoted thereon at points 20a and 20b are pivoted on a stationary shaft 29 and they are connected through a spring 30 so that the lever 28a is urged in the counterclockwise direction and the lever 28b is urged in the clockwise direction. Cam rollers 31a and 31b formed on the push levers 28a and 28b  are thus caused to abut against parts of the retaining hooks 2a and 2b, respectively. 
     For example, when the solenoid 27b is actuated to advance the solenoid rod 32b, the catching lever 22b is displaced from the position indicated by the two-dot chain line to the position indicated by the solid line, and the top end of the locking lever 17b always oscillated is restrained by the hook portion 21b, whereby the top end of the locking lever 17b is retained. If the cam roller 18 is raised in this state by rotation of the cam 14, the pivoting shaft 20b which has acted as the center of oscillation is turned in the counterclockwise direction with the top end of the locking lever 17b being as the center and the push lever 28b having the pivoting shaft 20b is turned from the position 28b1 indicated by the two-dot chain line to the position indicated by the solid line with the shaft 29 being as the center. The other end of the push lever 28b is displaced to turn the retaining hook 2b in the counterclockwise direction and locate the retaining hook 2b at the position for engagement with the hook 9b, whereby the hook 9b on the balanced lever is retained or retaining of the hook 9b is maintained. 
     When the other solenoid 27a is actuated, in the same manner as described above, the hook on the balanced lever is retained or retaining of the hook is maintained, and the heald frame is raised through the jack lever 12 shown in FIG. 1 according to the desired weave texture. 
     On-off control of the solenoids 27a and 27b is accomplished by an electronic control circuit 33. More specifically, in the weave texture reading zone, a data of a desired weave texture 34 is put and stored in a storing element, that is, a memory ROM1, through a key operation board 35, and the input signal is checked at a point 37 by a small plotter 36 and if there is no error, the memory ROM1 is taked out from the reading zone and attached to a dobby control circuit. In the electronic control circuit, a control program stored in a memory ROM2 and the weave texture signal stored in the memory ROM1 are processed by a central processor unit CPU, and on-off control of the solenoids 27a and 27b at the predetermined positions is performed through a switching circuit SW. 
     In the normal state, a desired weave texture is formed according to the stored data of the memory ROM1. In the case where the loom is stopped because of breakage of a weft thread and the loom is reversely rotated to reproduce a weft-broken shed, the data of the preceding one or two wefts is picked up co-operatively with the reverse rotation of the loom or according to another instruction and the catching levers 22a and 22b are actuated according to the picked-up data, whereby the desired shedding state is obtained. 
     In order to perform the so-called levelling operation of raising or lowering heald frame located at lower or upper positions for exchanging or knotting warp threads, a memory or switching circuit for actuating or de-energizing all the solenoids, which is arranged independently from the weave texture memory ROM1, is utilized. 
     Furthermore, there may be adopted a modification in which a plain weave texture is stored independently from the desired texture, the catch lever is actuated to form a shed according to the plain weave texture data. In this modification, when the loom is stopped in the vicinity of the crossing point, the mail heights of all the healds can be arranged at the substantially same level. That is, the function of the so-called tufting apparatus can be exerted. 
     FIG. 3 illustrates another embodiment in which the retaining hooks 2a and 2b are directly controlled by solenoids 38a and 38b or air cylinders through rods 39a and 39b thereof. In this embodiment, the retaining hook is made to stand by at the retaining position by the solenoid and when the retaining hook is going to engage with the hook portion of the movable hook, a force acting in the reverse direction is imposed on the solenoid or air cylinder actuated to displace the retaining hook because of the contact pressure of the movable hook. Accordingly, a solenoid or air cylinder capable of overcoming the above force is used. However, the structure of such solenoid or air cylinder is very simple and occurence of erroneous control or other trouble can be prevented effectively. Incidentally, an electronic control circuit having the same structure as that shown in FIG. 2 can be used as the electronic control circuit 33. 
     FIG. 4 illustrates still another embodiment which is applied to a hattersley dobby, where heald frames (not shown) are vertically moved through a wire cable 42 with rotation of a jack lever 40 around a stationary shaft 41. The top end of a lever 44 capable of oscillating with a stationary shaft 43 being as the center is connected to the jack lever 40 through a rod 45, and the intermediate portion of the lever 44 is pivoted on the intermendiate portion 47 of a connecting lever 46. Hook arms 48a and 48b are pivoted on both the ends of the connecting levers 46, and hooks 49a and 49b are mounted on the top ends of the hook arms 48a and 48b. Stoppers 50a and 50b for the hook arms 48a and 48b are secured on the side of the machine base. Reference numerals 51a and 51b represent a pair of reciprocating knives which make reciprocative movements alternately at a certain height so that they are engaged with and disengaged from the hooks 49a and 49b, and their reciprocative movements are made relative to the rotation of the loom. 
     Control of the vertical position of the hook arms 48a and 48b is accomplished by solenoids 52a and 52b or air cylinders arranged in the vertical direction. More specifically, the top ends of solenoid rods 53a and 53b which are raised and lowered by turn-on and turn-off of the solenoids 52a and 52b have abutting contact with the lower faces of the hook arms 48a and 48b, and on-off control of the solenoids 52a and 52b is accomplished by a control circuit 33 similar to the electronic control circuit 33 shown in FIG. 2 according to a desired weave texture.