HK1175823B - Plastic open mesh net manufacturing device and machine - Google Patents

Description

Plastic open mesh net manufacturing device and machine

Technical Field

The present invention relates to the field of devices and machines for manufacturing open mesh nets.

In the context of the present specification, the term "honeycomb net" is also used to denote an open mesh net, wherein several wires are connected by twisting adjacent wires to each other, thereby forming a net with openings resembling cells of a honeycomb. However, the present invention is not limited to hexagonal cells or double twisted nets.

The invention has been developed with particular attention paid to devices capable of twisting plastic wires and making open mesh or honeycomb nets.

In the simple structure of the present invention, each plastic wire is uniformly heated just before twisting. The invention also simplifies and facilitates the threading operation of the plastic thread and, in addition, in the field of manufacturing cellular nets, the device contributes to maintaining a uniform cellular shape.

Background

It is known to weave honeycomb meshes using twisted metal wires or twisted synthetic resin wires.

The honeycomb net is constructed using twisted wires that are adjacent to each other and twisted with each other. The strength and durability are very excellent, and thus such a net can be used for fencing, fostering, keeping down rocks, and the like. The twisted and woven synthetic resin honeycomb nets do not rust and do not corrode when compared with metal wire honeycomb nets, and thus they have better durability.

As for the strength and regularity of the mesh, an excellent one as shown in patent document JP 57-56556, which relates to a manufacturing method of a honeycomb mesh body, is developed.

JP 57-56556 shows how a forged, non-solid wire is preheated to a specified temperature, and then twisted under tension. After forming, the web body is heated without changing the desired shape, and then rapidly cooled to maintain that shape.

The prior patent documents JP 57-28645, JP 54-96183, JP 54-46970 also define the background art of the present invention.

The prior art has various disadvantages discussed below.

It is not simple to preheat the plastic wire uniformly (corresponding to the wire of the prior art patents) before twisting it, in particular by means of a heater or by means of a hot air zone. It often happens that locally uneven preheating occurs, making it difficult to subsequently twist and weave the wires into an open mesh or honeycomb mesh, where consistent shape and strength is desired.

Also when performing threading operations, each plastic wire must be threaded or inserted into a thread hole provided in the semi-cut gear of the back net twist auxiliary mechanism, the movement of which cooperates with a similar and corresponding front net twist mechanism. Each plastic wire must then be threaded or inserted into a corresponding wire hole of the twisting trimming gear of the front net twisting mechanism. This operation is critical since if a thread is mistakenly threaded into the wrong thread hole (e.g. of another front net twist mechanism), all threads will be offset and the entire threading operation will have to be performed again.

Such threading operations from the back net twist auxiliary mechanism to the front net twist mechanism of the known machines and devices have proved to be always cumbersome and involve a lot of work and time.

In addition, when two plastic wires are twisted in a machine of the known art, the same two plastic wires open, i.e. split, towards opposite sides to form the shape of a honeycomb, i.e. one of the openings of the open mesh. However, doing so, pulls the twisted portion of the net strongly in the opposite direction, so that it can deform to a position where the honeycomb shape is not properly obtained or maintained. Thus, it is difficult to twist threads and weave honeycomb nets having uniform and consistent shape and strength.

Disclosure of Invention

The object of the present invention is to solve the above problems. It is another object of the present invention to provide a device that can be used in a machine that produces strong, consistent and durable plastic open mesh or honeycomb webs at a relatively low cost, high production rate, and with little or no maintenance.

In order to achieve the above object, the present invention relates to a manufacturing apparatus of a plastic open mesh net or a honeycomb net, in which two corresponding thread holes respectively provided in a front net twist mechanism and a rear net twist auxiliary mechanism are connected by a heat conductive thread guide.

In a preferred but non-limiting example, the thermally conductive wire guide is in the form of a thermally conductive wire tube or catheter.

By this arrangement, each plastic wire is passed through the heated heat-conductive thread guide or preferably tube before twisting, so that the plastic wires are uniformly preheated by the simple structure to prevent unevenness of local preheating. The guide simplifies and facilitates the threading operation of the plastic wire from the back net twist auxiliary mechanism to the front net twist mechanism, especially in its preferred tubular form.

According to another aspect of the present invention, each twisting point can maintain its net width pitch and a uniform and consistent honeycomb shape just after output from the net twisting mechanism, so that the woven honeycomb net has uniform strength.

The machine for producing plastic nets according to the present invention provides a net twisting mechanism in which pairs of twisting edger gears are arranged in the width direction of the produced net. These twisting trimming gears have thread holes for plastic threads and are associated in pairs so that they can rotate together to twist two threads passing through their respective thread holes. After some rotation of these pairs of twisting trim gears, which rotation results in corresponding twisting of several pairs of plastic wires distributed along the width of the produced net, each pair of twisting trim gears is separated and one or both of the respective twisting trim gears are laterally offset until it coincides with another adjacent twisting trim gear to form another pair of twisting trim gears which is then rotated to form a subsequent twisted portion of the net in the form of a honeycomb. The twist trim gear then returns to the original position to form another twisted portion of the net by rotation and twisting of the wire.

The back of the net twisting mechanism is provided with a net twisting auxiliary mechanism, and the net twisting auxiliary mechanism is provided with corresponding twisting trimming gears which correspond to the twisting trimming gears of the net twisting mechanism in a one-to-one manner. Each twisting trimming gear of the net twisting auxiliary mechanism has a corresponding thread hole for a plastic thread and is synchronized in rotation and separation/offset in the net width direction with the corresponding twisting trimming gear of the front net twisting mechanism.

The back twisting mechanism is arranged at the back side of the net twisting auxiliary mechanism and comprises a guide gear which is synchronous with each pair of twisting trimming gears of the net twisting mechanism and the net twisting auxiliary mechanism in rotation. A front supply bobbin or drum for supplying the plastic wire to one of a pair of twisting trimming gears is installed inside the guide gear, and a back supply bobbin or drum for supplying the plastic wire to the other twisting trimming gear is provided at the back of the guide gear. The plastic wire from the back supply bobbin is hooked at the outer axial passage of the guide gear and rotates together with the guide gear.

Guide means for varying the suspension of the plastic wire fed from each rear feed bobbin are mounted to the corresponding guide gear between the front and rear feed bobbins.

The heating device is arranged in the area where the heat-conducting silk thread guide piece enables the rear net twisting auxiliary mechanism and the silk thread hole of the corresponding twisting trimming gear of the net twisting mechanism to be connected. The heating device heats the plastic wire guided by the heat-conducting wire guide uniformly, especially when the wire guide is in the form of a heat-conducting wire tube inside which the plastic wire runs.

According to another aspect of the invention, a holding device in the form of a preferred holding comb is provided after the net twist mechanism to improve the uniformity and consistency of the manufactured plastic honeycomb net. These retaining means comprise at least a plurality of concave portions, each of which is arranged in a position corresponding to each twisted portion of the honeycomb net in the net direction. These retaining devices are preferably, but not exclusively, made of corrugated injection-molded parts. The holding device is moved forward a little at the same speed as the feeding speed of the honeycomb net from the net twist mechanism, and then quickly returned to the original position to repeat the forward movement.

With the plastic honeycomb net manufacturing machine according to the present invention, plastic wires are passed through respective heat-conductive thread guides, preferably heat-conductive thread pipes, which connect respective thread holes in the trimming gears provided in the front net twist mechanism and the rear net twist auxiliary mechanism. The heating device for uniformly heating the plastic wire by the heat-conductive thread guide (or preferably the tube) makes it possible to prevent uneven twisting due to unevenness of preheating so as to weave the plastic honeycomb net having a uniform shape and strength.

In addition, since the heat-conductive thread guide or preferably the tube is provided, it is possible to omit the conventional troublesome operation of threading a plastic wire into the thread hole of the front net twist mechanism after the plastic wire has been threaded into the thread hole of the rear net auxiliary twist mechanism, thereby simplifying and facilitating the threading operation of the plastic wire to remarkably shorten the operation time.

After or downstream of the front net twist mechanism, there is provided a holding device, preferably but not exclusively in the form of a corrugated holding device, which allows to keep the twisted parts at the correct distance or pitch in the net width direction just after they are fed from the net twist mechanism, in which holding device there is correspondingly at least one concave portion at a location corresponding to each twisted part of the honeycomb net in the net width direction, wherein these holding devices are shifted forward some at the same speed as the feeding speed of the honeycomb net from the net twist mechanism, and then quickly return to the original position and repeat this forward movement. In this way, even if two wires are opened or moved apart to both sides by constant tension, it is possible to prevent deformation of the twisted portion of the net even if the right or left side is strongly pulled, thereby weaving a honeycomb net having a uniform honeycomb shape and a prescribed strength.

Drawings

Further characteristics and advantages will emerge from the following detailed description of a preferred but non-limiting embodiment of the invention, with reference to the attached drawings given as non-limiting examples, in which:

FIG. 1 is a schematic view of a plastic honeycomb web making machine according to the present invention;

FIG. 2 is a partial perspective view of the rotation of the twisting edger gears in the net twist mechanism and net twist assist mechanism;

FIG. 3 is a partial perspective view of the separation/offset of the twisting trimming gear of FIG. 2;

FIG. 4 is a partial perspective view of the back twisting mechanism;

fig. 5 is a partial perspective view of a holding device of the invention in the form of a holding device; and

fig. 6A-6C are partial sectional views illustrating an explanation of the movement of the holding device of fig. 5.

Detailed Description

Referring now to fig. 1 to 3, a plastic open mesh net manufacturing machine 1 includes a net twisting mechanism 2 to twist plastic wires a and weave the plastic wires a to form a honeycomb net b. The net twist auxiliary mechanism or auxiliary mechanism 3 is arranged behind the net twist mechanism 2. Also visible in fig. 1 are a guide gear 41, a front supply bobbin 42 for supplying the plastic wire a, a rear supply bobbin 43, a twist back mechanism 4 comprising a guide 44 mounted between the front supply bobbin 42 and the rear supply bobbin 43. In addition, machine 1 comprises heating device 5 to uniformly heat plastic wires a running inside heat-conductive thread pipe 51, wherein heat-conductive thread pipe 51 is installed between net twist mechanism 2 and net twist auxiliary mechanism 3. A holding device 6, preferably a holding means, is mounted in front of the net twist mechanism 2 to maintain the honeycomb net shape.

The net twist mechanism 2 includes a pair of twisting semi-cut gears 21 and 22 which are repeatedly rotated together and then separated/shifted in the net width direction to weave the plastic wire a into a plastic wire honeycomb net b. The honeycomb net b is continuously produced by the net twisting mechanism 2. In the net twist mechanism 2, racks 23 are provided (at the top and bottom) and have teeth that mate with the twist cut-off gears 21 and 22 to rotate the gears 21 and 22.

The net twist mechanism 2 has threaded holes 21a and 22a for plastic wire a and, for example, pairs of twist trimming gears 21 and 22 are installed one beside the other in the net width direction. After twisting the plastic wire a passing through the screw holes 21a and 22a provided in the paired twisting edgecomb gears 21 and 22, respectively, rotating together several times, one or both of the twisting edgecomb gears 21 and 22 are separated and/or shifted in the net width direction until the top thereof corresponds to the adjacent and different twisting edgecomb gears 21 and 22 on the bottom. Then, the new corresponding and paired twisting trim gears 21 and 22 are rotated so that the two plastic wires a passing through the screw holes 21a, 22a of the twisting trim gears 21 and 22 are twisted several times. After this operation, the twisting trim gear is returned to the original position and the twisting operation is repeated by rotating together using the previously corresponding twisting trim gears 21 and 22, and honeycomb net b is woven.

The net twist mechanism 2 comprises, for example, a structure in which pairs of top and bottom gears 21 and 22 are installed in the width direction of the net. At the corresponding top and bottom positions of the paired twisting trimming gears 21 and 22, threaded holes 21a, 22a are formed, respectively, and a plastic wire a is threaded into each of the threaded holes 21a, 22 a. The pair of top and bottom twisting trim gears 21 and 22 are configured to rotate several times and eventually reach similar top and bottom positions illustrated in fig. 1, with the twisting trim gear 21 again being disposed above the other, corresponding twisting trim gear 22.

The topmost twisting trim gear 21 and the bottommost twisting trim gear 22 are configured such that one or both are separated or offset in the net width direction until they correspond to the other twisting trim gears 21 and 22, respectively, in a top-to-bottom adjacent manner.

On the back of said net twist mechanism 2, i.e. upstream in the feeding direction of the plastic wire a, a net twist auxiliary structure 3 is provided, the net twist auxiliary mechanism 3 having respective twist trimming gear aids 31, 32, each of which individually corresponds to a respective twist trimming gear 21, 22 of the net twist mechanism 2.

Each of the twisting trimming gear aids 31 and 32 in the net twisting aid mechanism 3 has a corresponding threaded hole for the plastic wire a to be threaded. Each of the twisting shaving gear assistants 31 and 32 in the net twisting auxiliary mechanism 3 is synchronized in rotation and separation/offset in the net width direction, and is configured to rotate and separate/offset in the net width direction. In the net twist auxiliary mechanism 3, racks 33 are arranged on the top and bottom to match the teeth of the twist shaving gear auxiliary pieces 31, 32.

The net twist auxiliary mechanism 3 has almost the same construction as the net twist mechanism 2 due to the same movement as the net twist mechanism 2. This serves to prevent the respective heat-conductive threaded pipes 51 from contacting and twisting each other due to the rotational movement of the twisting trimming gears 21, 22 and the separating/offsetting movement in the net width direction. In fact, if the heat-conductive threaded pipes 51 are in contact or twisted with respect to each other, the rotation and separation/offset of the twisting trimming gears 21, 22 implemented in the net twist structure 2 may become difficult or problematic. Furthermore, if the heat-conductive threaded pipe 51 is broken or bent, or if the penetrated plastic wire a is cut or twisted, it becomes impossible to weave the honeycomb net b. The net twist auxiliary mechanism 3 is provided at the back of the net twist mechanism 2 to prevent this phenomenon.

The back twisting mechanism 4 prevents additional twisting of the plastic wire a by twisting back the plastic rope a continuously supplied to the net twist auxiliary mechanism 3. In fact, improper additional twisting of plastic wire a continuously fed to net twist auxiliary mechanism 3 and subsequent twisting in net twist mechanism 2 may cause difficulties in smoothly forming honeycomb net b, and this may adversely affect the strength of honeycomb net b.

Furthermore, twist back mechanism 4 can prevent each plastic wire a continuously supplied to net twist auxiliary mechanism 3 from being interlaced due to the rotation of each twist trimming gear 31, 32 in net twist auxiliary mechanism 3 and the separating/offsetting motion in the net width direction, so as to smoothly supply plastic wire a to net twist auxiliary mechanism 3.

The twist back mechanism 4 includes a guide gear 41, a front supply bobbin 42 for supplying the plastic wire a, a rear supply bobbin 43 for supplying another plastic wire a, a guide device located at the back of the net twist auxiliary mechanism 3, and the like. Going backwards, the guide gear 41, the front supply bobbin 42, the guide 44 and the rear supply bobbin 43 are arranged in this order.

The guide gear 41 rotates to cooperate with each pair of the trimming gears 21, 22 in the net twist mechanism 2 and the net twist auxiliary mechanism 3; 31. 32 are synchronized. A guide gear larger in diameter than the front supply bobbin 42 is provided behind the net twist assist mechanism 3. A large gear is formed at an outer periphery of the guide gear 41, and a rotation gear 41a engaged with the large gear is provided to rotate the guide gear 41. At the outer peripheral portion of the guide gear 41, an outer peripheral passage 41b is formed to hook and rotate the plastic wire a supplied from the rear supply bobbin 43.

The front supply bobbin 42 supplies the plastic wire a to one of the twisting trimming gears 21 or 22 in the net twisting mechanism 2 through one of the twisting trimming gear assistants 31 or 32 located in the corresponding and paired net twisting auxiliary mechanisms 3. The plastic wire a is wound at the front supply bobbin 42. The front supply bobbin 42 is disposed inside the periphery of the guide gear 41. The front supply bobbin 42 is installed such that it does not prevent the rotation of the guide gear 41.

The rear supply bobbin 43 supplies the plastic wire a, which is hooked at the outer circumferential channel 41b of the guide gear 41 and rotated to the other twisting edger gear 22 or 21 in the net twisting mechanism 2 by the other twisting edger gear assist 32 or 31 in the corresponding and paired net twisting auxiliary mechanism 3. The plastic wire a is wound at the rear supply bobbin 43 and it is arranged at the back of the guide gear 41 and the guide 44.

The guide 44 is disposed between the front and rear supply bobbins 42 and 43 and is a means for changing the suspension of the plastic wire a supplied from each rear supply bobbin 43 to correspond to the guide gear 41. In the guide 44 (see fig. 4), stoppers 44a are installed to hook the plastic wire a, and these stoppers 44a are shifted upward and downward or rightward and leftward in conjunction with the rotation of the respective shaving gears 21, 22 and 31, 32 and the dividing/shifting movement in the net width direction, so as to smooth the supply of the plastic wire a from the rear supply bobbin 43.

Each threaded hole in the trimming gears 21, 22 in the front net twist mechanism 2 is connected to a corresponding threaded hole in the trimming gears 31, 32 in the rear net twist auxiliary mechanism 3 by means of a heat-conducting threaded pipe 51, wherein the plastic wire a runs inside the heat-conducting threaded pipe 51. Each heat-conductive threaded pipe 51 is correspondingly offset in parallel relation at the same speed as the twisting trimming gear.

One end of the heat-conductive thread pipe 51 is connected to the screw hole 21a of the twisting flange gear 21 in the net twisting mechanism 2, and the other end of the heat-conductive thread pipe 51 is connected to the screw hole 31a of the twisting flange gear auxiliary 31 in the net twisting auxiliary mechanism 3, the twisting flange gear auxiliary 31 corresponding to the twisting flange gear 21, being synchronized in rotation and separation/offset in the net width direction. Similarly, one end of another heat-conductive thread pipe 51 is connected to the screw hole 22a of the twisting trimming gear 22 in the net twisting mechanism 2, and the other end of the heat-conductive thread pipe 51 is connected to the screw hole 32a of the twisting trimming gear auxiliary 32 in the net twisting auxiliary mechanism 3, the twisting trimming gear auxiliary 32 corresponding to the twisting trimming gear 22, being synchronized in rotation and separation/offset in the net width direction.

Each of the thermally conductive threaded pipes 51 is hollow inside so that one plastic wire a passes therethrough. If one plastic wire is threaded from each twisting trimming gear assist 31, 32 in the net twisting assist mechanism 3 to each twisting trimming gear 21, 22 of the corresponding width by means of the heat-conductive threaded pipe 51, the threading can be performed continuously and in its simplest form.

Advantageously, each heat-conductive threaded pipe 51 is configured as a pipe (e.g., a metal cylindrical pipe) that conducts heat by heating. If each heat-conductive threaded pipe 51 is heated by the heating device 5, heat is transferred to all of the heat-conductive threaded pipes 51. Each penetrated plastic wire a is then uniformly heated and internally softened by the heat-conductive threaded pipe 51 as it is deflected toward the front net twist mechanism 2. Each softened plastic wire a is then smoothly twisted and woven into a honeycomb net b without twisting resistance at the moment of twisting.

The heating device 5 as mentioned before is a device that uniformly heats the plastic wire a that penetrates into the heat conductive wire tube 51. The heating device 5 is arranged in the pipe connection area, wherein several heat-conducting filament pipes 51 are mounted parallel to each other between the front net twist mechanism 2 and the rear net twist auxiliary mechanism 3. The heating devices 5 are arranged parallel to each other in a transverse direction with respect to the plurality of thermally conductive filament tubes 51. For the heating device 5, for example, an electric heater is used. The spacing between net twist mechanism 2 and net twist auxiliary mechanism 3, allocated for heating device 5 and each thermally conductive filament tube 51, is, for example, a closed space, so that heat is kept inside the space with no or little dispersion to the outside thereof.

In front of the net twist mechanism 2, two holding devices 6 are provided, which resemble combs and are preferably holding devices. The holding device 6 maintains the honeycomb shape woven into the honeycomb net b supplied by the net twist mechanism 2. The two holding devices 6 are connected to each other by a connecting plate 62 (see fig. 5) and perform the same action. Each holding device 6 has at least a concave portion 61 since it corresponds to each twisted portion c in the net width direction in honeycomb net b fed from net twist mechanism 2. Each holding machine 6 can move forward at the same speed as the feeding speed of honeycomb net b through net twist mechanism 2. After being offset a little forward, it quickly returns to the initial point and is configured to repeat the motion. And the two holding devices 6 connected by the connecting plate 62 are configured to be driven by a driving mechanism (not shown) in conjunction with the net twist mechanism 2.

The concave portions 61 are, for example, rounded so as not to be broken when the twisted portions c are pushed out from the top. Many of these portions are formed at the same intervals under the oval holding device 6. The holding device 6 is formed in a corrugated shape when viewed from the front. It is possible that each twisted portion c in the width direction of honeycomb net b fed from net twist mechanism 2 is located below correspondingly shaped concave portion 61 provided below oval holding device 6. In the preferred example shown in the figures, twisted portions c of honeycomb net b are arranged in alternating recessed portions 61 of retaining device 6. This means that the concave portions 61 are alternately emptied or occupied by the twisted portions c of the honeycomb net b.

As clearly seen in fig. 6A-6C, the concave portions 61 formed in the two injection molding machines 6 disposed one behind the other are aligned. And in the two holding devices 6, the positions of the twisted portions c at both sides of the hexagonal lattice of the honeycomb net b become the central positions of the hexagonal lattice in the back/front direction. Concave portions 61 aligned in the back/front direction on both holding machines 6 are thus alternately emptied or occupied by twisted portions c of honeycomb net b. This means that if the twisted portion of honeycomb net b is located within concave portion 61 of front retaining device 6, concave portion 61 of rear retaining device 6 aligned in the rear/front direction is empty.

The rear holding device provided just beside the net twist mechanism 2 pushes the twisted portion c which becomes the right and left sides of the hexagon of the honeycomb net b just fed from the net twist mechanism 2, and the concave portions 61 thereof are alternately filled and emptied. In the joined condition, at the same speed as that of the honeycomb net b, the holding device is offset towards the front by the following total length: the total length is equal to the length of twisted portion c (which becomes the right and left sides of the hexagon of honeycomb net b) and the sine value (sine) (ratio of front side to inclined side) multiplied by the distance from the last end point of twisted portion c to the starting end point of the twisted portion of the next honeycomb net b; then quickly returns to the original position and the movement is repeated.

The two plastic wire twisted parts supplied from twisting trimming gears 21, 22 of net twisting mechanism 2, which become the right and left sides of honeycomb net b, are accompanied by the separating/offsetting movements of top and bottom trimming gears 21, 22, thereby separating the right and left side wires from the rearmost end points of twisted part c to correspond to the adjacent twisting trimming gears. Subsequently, the new pair of top and bottom and rotating parts are twisted and the honeycomb net b is woven.

At this time, the two plastic wires a are separated rightward and leftward from the last end point of the twisted portion c.

If strongly pulled to the right and left, the final end points of the twisted portions c are connected to the concave portions 61 formed below the holding means 6, so that they are maintained at the central position without being pulled in the right or left direction, and maintain the honeycomb hexagonal shape.

Particularly right after twisting, the plastic wire a remains soft due to heating, whereby if the softening conditions of the right and left plastic wires a are slightly different, there is a risk (when using machines and devices of known type) that the plastic wire a is unevenly pulled to the right or left side, which may cause the honeycomb shape to break. With the holding means of the invention, particularly but not exclusively in the form of the holding means 6, the last end edge of each twisted portion c is connected to or enters the recessed portion 61 and is held therein, so that the honeycomb shape can be maintained without being pulled to the right or left.

The other holding means arranged at the front push from the top and engage the twisted portions c of the central portion located at the two sides of the hexagon of the honeycomb net b pushed by the rear holding means 6 and linked in conjunction with the aforementioned rear injection moulding means 6 integrated by the connecting plates 62, working with exactly the same movement.

Just after weaving into the honeycomb shape, the honeycomb net b is softened and the shape may be deformed just before heating, but the deformation of the honeycomb shape is prevented and maintained by the rear and front holding devices 6.

After the holding device 6, a cylindrical conveying roller 7 that conveys the just-woven honeycomb web b forward is installed. On the peripheral surface of the conveying roller 7, pins 71 project radially, distributed at constant intervals on the periphery. The rotating pin 71 hooks and pulls the hexagonal top side of the honeycomb shape, so that the honeycomb net b moves forward and is wound on a winding device or a reel which is disposed behind the conveying roller and which is not shown in the figure.

The operation of the preferred embodiment of the present invention will now be explained.

Plastic wires a supplied from respective rear supply bobbins of twist back mechanism 4 provided at the back are inserted into respective thread holes 31a of twisting trimming gear auxiliary 31 located at the front of net twist auxiliary mechanism 3, for example. It then penetrates into the heat-conductive thread pipe 51 and its edge protrudes from the thread hole 22a of the twisting trimming gear 22 in the net twisting mechanism 2 disposed in front thereof.

Similarly, the plastic wire a supplied from each rear supply bobbin 43 in the back twist back mechanism 4 is hooked at the outer peripheral passage 41b of the guide gear 41 provided at the outer peripheral edge of each front supply bobbin 42 to correspond to the front of the guide 44. Each of the thread holes 32 of the twisting shaving gear auxiliary member 32, which is located in, for example, the front net twist of the guide gear 41, is inserted through each of the guide devices 44 corresponding at the front, penetrates into the heat-conductive thread pipe 51 and its edge protrudes from the thread hole 22a of the twisting shaving gear 22 in the net twisting mechanism 2 disposed in front thereof.

As described above, after the plastic wire a is set to the manufacturing machine 1 of the plastic honeycomb net b, the heating device 5 heats so as to heat the respective heat conductive filament pipes 51. Once the heat-conductive wire tube 51 is heated, the heat thereof is transferred to all the heat-conductive wire tubes 51, so that the plastic wires a inside thereof are uniformly heated and softened. In this way, after the plastic wire a is softened so that the twisting resistance is reduced, the net twist mechanism 2 and the net twist auxiliary mechanism 3 linked with the net twist mechanism 2, and the guide gear 41 and the guide 44 of the back twist mechanism 4 are all activated.

The operation of the net twist mechanism 2 is: after twisting two plastic wires a threaded into the thread holes 21a, 22a several times, wherein the thread holes 21a, 22a are associated with each other and paired by the corresponding twisting trim gears 21, one or both of these twisting trim gears 21, 22 are separated/shifted in the net width direction to reach the adjacent, different twisting trim gears 21, 22 and paired with the twisting trim gears 21, 22. By the rotation of the new corresponding and paired twisting edger gears 21, 22, the two plastic wires a are twisted several times, then returned to the original position, and repeated to correspond to the previous twisting edger gears 21, 22 and finally rotated again. In this way, honeycomb net b is woven and conveyed one grid after another to the front of net twist mechanism 2.

The heat conductive thread pipe 51 between the net twist mechanism 2 and the net twist auxiliary mechanism 3 is synchronized in rotation of the twist cut-off gears 21, 22 and separation/offset in the net width direction to correspond to the net twist mechanism 2 for rotation and separation/offset in the net width direction, respectively.

Similarly, the back twist mechanism 4 at the rear of the net twist auxiliary mechanism 3 is synchronized with the separation/shift of the twist trimming gears 21, 22 in the net twist mechanism 2 in rotation and in the net width direction by twisting the plastic wire a continuously fed from the front feeding bobbin 42 and the rear feeding bobbin 43 back to the net twist auxiliary mechanism 3. Thereby, twisting is prevented from being added to the plastic wire a twisted in the net twist auxiliary mechanism. Further, the plastic wires a continuously supplied to the net twist auxiliary mechanism 3 are prevented from being interlaced with each other by the rotational movement of each of the twist auxiliary edger gears 31, 32 located in the net twist auxiliary mechanism 3 and the dividing/offsetting movement in the net width direction.

When the rearmost end portions of the twisted portion c of the plastic wire are passed through the thread holes 21a, 22a of the twisting shaving gears 21, 22 located in the net twisting mechanism 2, the rear holding device 6 moves downward from the top and pushes the rearmost end portion of the twisted portion c located inside the concave portion 61 formed below the surface of the rear holding device 6, thereby connecting and inserting the twisted portion c (see fig. 6A). When plastic wire a is still in a softened state after leaving net twist mechanism 2, twisted portions c are held together and maintained by concave portion 61 of rear holding device 6. Just after that, the two plastic wires a are pulled toward the right and left, respectively, and are thus separated, but the rearmost end portions of the respective twisted portions c are held together by the concave portion 61 of the holding device 6, so that it is possible to maintain the honeycomb shape without being shifted to the right and/or left.

When concave portion 61 of rear holding device 6 near net twist mechanism 2 pushes the rearmost part of plastic wire a of each twisted part c and thus remains connected, concave portion 61 of front holding device 6 simultaneously moves downward from the top, pushing and connecting the rearmost end part of each twisted part that has been previously conveyed forward by one lay length.

After each concave portion 61 of holding device 6 pushes and connects each twisted portion of the rearmost end portion of corresponding plastic wire a at the same speed as the forward speed of honeycomb net B from net twisting mechanism 2, holding device 6 is shifted forward by a total length of twisted portion C (which becomes the right and left sides of honeycomb net B) and sine value (sine) (ratio of front side to inclined side) multiplied by the distance from the rearmost end point of twisted portion C to the starting end point of the twisted portion of next honeycomb net B (see fig. 6B, 6C), then moves fast to the top, moves down from the top while returning to the rear initial position, pushes and connects the rearmost end portion of plastic wire a just delivered from net twisting mechanism 2, each plastic wire a being twisted by portion C (see fig. 6A). The reciprocal holding means 6 repeats this movement.

Immediately after being woven into a honeycomb shape, the honeycomb net b remains soft due to heating and there is a possibility of its deformation, and due to the above-described reciprocating mechanism of the holding device 6, the shape of each twisted portion c is held and is not laterally twisted, so that it prevents the deformation of the honeycomb shape.

The honeycomb net b woven by the net twist mechanism 2 moves forward and is wound by a winding device (not shown) since the rotating pin 71 of the forward roller 7 provided behind the holding device 6 hooks and pulls the top side of the honeycomb hexagon.

In this regard, the embodiments and features of the present invention can be modified and varied by employing equivalents within the scope of the invention as claimed.

Claims (9)

1. A twisting device for twisting plastic wires to form a plastic open mesh net, the device comprising a front twisting mechanism and a rear twisting mechanism, the front and rear twisting mechanisms having respective pairs of front and rear thread-holes for receiving plastic wires to be twisted, each pair of front and rear thread-holes being connected by a respective heat-conductive thread guide.

2. The twisting apparatus of claim 1, wherein each thermally conductive thread guide is a thermally conductive tube.

3. The twisting device of claim 2, wherein each heat conductive tube is a metal tube.

4. The twisting device according to any one of claims 1 to 3, further comprising a heating device disposed between the front and rear twisting mechanisms to heat the heat-conductive thread guide.

5. The twisting device of claim 4, wherein the thermally conductive thread guide and the heating device are disposed in an enclosed space.

6. A machine for twisting plastic wires to form a plastic open mesh net, the machine comprising: -a feeding device for feeding plastic wires, -a heating device for heating and softening the plastic wires, -a twisting device for twisting the softened plastic wires and forming an open mesh net, -a collecting device for collecting the formed open mesh net, the machine further comprising a holding device arranged between the twisting device and the collecting device to hold the open mesh net just formed in a uniform shape, wherein the twisting device is a twisting device according to any of claims 1 to 5.

7. A machine according to claim 6, wherein the holding means comprise at least a plurality of recessed portions, each recessed portion being provided at a position corresponding to a respective twisted portion of the open mesh net in the direction of advancement of the open mesh net.

8. A machine according to claim 7, wherein the holding means comprises two comb-like holding elements connected together.

9. A machine according to claim 6 or 7, wherein the retaining means is formed by a corrugated injection moulding.