Automatic wire feeding mechanism for automatic wire threading EDM wire cutting machine

Abstract

An automatic lower wire feeding mechanism for an automatic wire threading electric spark wire cutting machine tool is characterized in that: a CNC push-pull mechanism composed of a motor, a sprocket, and a chain pushes and pulls a wire drawing trolley to pull the electrode wire from the lower wire guide head clamp of the machine tool to the bottom of the wire drum, and then a wire hooking mechanism hooks the electrode wire into the wire drum wire clamp to complete the task of pulling the electrode wire from the lower wire guide head to the bottom of the wire drum and into the wire drum wire clamp during the automatic wire threading process of the machine tool. The trolley wire clamp is normally closed and can be opened automatically to complete the clamping and releasing of the wire. At the same time, the gravity and foldable flexibility of the chain are used to store it in a chain storage box outside the processing area to avoid the adhesion of etched materials during processing. In addition, a detection function is designed to detect whether the electrode wire head is threaded in place in the wire drawing trolley. This mechanism improves the reliability and success rate of automatic wire threading.

Description

Technical Field

[0001] The present invention relates to the technical field of wire-cut electric discharge machining, and in particular to an automatic lower wire feeding mechanism for a CNC reciprocating wire-cut electric discharge machine tool. The lower wire feeding mechanism is used to automatically clamp the electrode wire head that passes through the lower wire guide nozzle and the lower main guide wheel mechanism (referred to as "lower wire guide head") of the machine tool, and then pull it to the lower part of the wire drum of the machine tool and allow the electrode wire to enter the automatic wire clamp of the wire drum. Background Art

[0002] As a metal cutting processing equipment, CNC reciprocating wire EDM (abbreviated as: EDM Wire Cutting Machine) is widely used in the processing of precision and complex parts in manufacturing industries such as molds, aerospace, automobiles, energy, precision instruments, medical equipment, and electronic products, and occupies an important position in industrial production. EDM wire cutting uses a continuously moving thin metal wire (called electrode wire) as an electrode to perform pulsed spark discharge to erode metal and cut the workpiece into shape. Wire threading is required before or during the online cutting process. At present, most EDM Wire Cutting Machines can only use manual wire threading. Manual wire threading is highly professional and requires professional operation. It also has a complex process, high requirements, large workload, and low efficiency. To this end, in recent years, technicians in this field have been working hard to research and develop fully automatic wire threading devices and methods suitable for EDM Wire Cutting Machines. Fully automatic wire threading is a complex and detailed system engineering in the field of wire cutting technology of electric spark machining. It has high process requirements, many difficulties and great technical difficulty. It has long been a technical problem in this field. Among them, how to automatically clamp the electrode wire coming out of the lower wire guide head (lower wire guide nozzle and lower main guide wheel mechanism) and then pull it to the lower part of the wire drum of the machine tool, and make the electrode wire enter the automatic wire clamp of the wire drum is one of the technical difficulties that need to be overcome.

[0003] In an automatic wire-threading CNC reciprocating wire EDM machine, after the automatic wire-threading system passes the electrode wire through the lower wire guide head, the existing technology usually uses a wire guide tube with a roller lower wire feeding mechanism as the power, and uses a pressure fluid (gas or liquid) as the auxiliary to directly guide the soft and thin electrode wire into the automatic wire clamp of the machine tool wire barrel. However, this solution has the following shortcomings: first, the mechanism transmits the soft and thin electrode wire over a long distance, and the electrode wire is prone to instability during transmission, making transmission difficult; second, the mechanism has a long wire guide tube, and in actual use, thick electric spark erosion products are easily accumulated in the inner hole of the wire guide tube, resulting in blockage of the wire guide channel, causing failure of automatic wire threading; third, the mechanism is also equipped with a roller lower wire feeding mechanism and a liquid and gas guide nozzle, and the structure is complex and difficult to disassemble and clean.

[0004] In view of this, the present invention proposes an automated lower wire feeding mechanism suitable for automatic wire threading of an electric spark wire cutting machine tool to solve the technical problem and ensure the success of automatic wire threading at the bottom of the machine tool. Summary of the invention

[0005] The present invention provides an automatic lower wire feeding mechanism for an automatic wire threading electric spark wire cutting machine, the purpose of which is to solve the problem of automatic wire threading reliability in a path in which the electrode wire coming out of the lower wire guide head (lower wire guide nozzle and lower main guide wheel mechanism) of the machine tool is automatically clamped and then pulled to the lower part of the wire drum and fed into the automatic wire clamp of the wire drum.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: an automatic wire feeding mechanism for an automatic wire threading electric spark wire cutting machine, the innovation of which lies in: including a push-pull mechanism, a wire clamping trolley, a wire hooking mechanism and a trolley wire clamp opening mechanism.

[0007] The lower wire feeding path of the machine tool is defined as the position from the wire head of the electrode wire horizontally passing through the lower wire guide head of the machine tool to the position below the wire drum, with the wire head position being the front end position and the position below the wire drum being the rear end position.

[0008] The push-pull mechanism is a mechanism used to push and pull the wire-clamping trolley on the lower wire feeding path, and the mechanism is composed of a guide rail and a linear drive mechanism. The guide rail and the linear drive mechanism are positioned and installed on a component that is relatively stationary with the lower wire arm of the machine tool. A moving structure that is compatible with the guide rail is provided on the wire-clamping trolley. The wire-clamping trolley moves in coordination with the guide rail through the moving structure, so that the wire-clamping trolley can reciprocate along the guide rail under the constraint of the guide rail. The linear drive mechanism has a push-pull action end. In the working state, the linear drive mechanism drives the wire-clamping trolley to push forward or pull backward between the front end position and the rear end position through the push-pull action end.

[0009] The wire drawing trolley is a clamp used to clamp the electrode wire head and feed the wire on the lower wire feeding path. The clamp is provided with a clamping mechanism for clamping the electrode wire head and a spring for forcing the clamping mechanism to be in a normally closed state. In the assembled state, the spring acts on the clamping mechanism to make the clamping mouth of the clamping mechanism in a normally closed state, thereby forming a normally closed wire clamp. The normally closed wire clamp is provided with a top pressure point corresponding to the spring to open the clamping mechanism.

[0010] The wire hooking mechanism is a wire hooking mechanism used to hook the electrode wire from the bottom of the wire drum into the wire clamp of the wire drum, and the wire hooking mechanism includes a first wire hooking block, a second wire hooking block and a lifting mechanism, wherein the first wire hooking block is located on one side of the wire drum, and a first wire hooking surface is provided on the first wire hooking block facing upward, and the first wire hooking surface is directly below the electrode wire. The second wire hooking block is located on the other side of the wire drum, and a second wire hooking surface is provided on the second wire hooking block facing upward, and the second wire hooking surface is directly below the electrode wire. The lifting mechanism is a linear moving mechanism controlled by the automatic wire threading system of the machine tool, and the linear moving mechanism is positioned and installed relative to the wire drum support or the wire drum drag plate, and the linear moving mechanism has a movable extension end, and the movable extension end is respectively fixed or positioned with the first wire hooking block and the second wire hooking block, and the movable extension end moves up and down under the control of the automatic wire threading system of the machine tool.

[0011] The trolley wire clamp opening mechanism is a pressing mechanism capable of opening the normally closed wire clamp on the wire drawing trolley. The pressing mechanism is composed of two sets of front-end pressing mechanism and rear-end pressing mechanism. The front-end pressing mechanism is positioned and installed at the front-end position and is externally arranged relative to the pressing point of the normally closed wire clamp of the wire drawing trolley. The rear-end pressing mechanism is positioned and installed at the rear-end position and is externally arranged relative to the pressing point of the normally closed wire clamp of the wire drawing trolley. The front-end pressing mechanism is provided with a front pressing output end controlled by the automatic wire threading system of the machine tool. In the working state, when the wire drawing trolley runs to the front-end position, the front pressing output end extends and acts on the pressing point of the normally closed wire clamp under the control of the automatic wire threading system of the machine tool to overcome the spring force to open the clamping mechanism on the wire drawing trolley. When the wire head of the electrode wire is fed into the clamping mechanism, the front pressing output end retracts to complete the wire clamping. The rear end pressing mechanism is provided with a rear pressing output end which is controlled by the automatic wire threading system of the machine tool. In the working state, when the wire drawing trolley moves to the rear end position and the wire hooking mechanism hooks the electrode wire from the bottom of the wire drum into the wire clamp of the wire drum, the rear pressing output end extends out under the control of the automatic wire threading system of the machine tool and acts on the pressing point of the normally closed wire clamp to overcome the spring force to open the clamping mechanism on the wire drawing trolley and complete the wire loosening.

[0012] The relevant contents in the above technical solution are explained as follows:

[0013] 1. In the above scheme, the "normally closed wire clamp" refers to the wire clamp being in a closed clamping state without external force intervention. Normally closed is relative to normally open. The wire clamp is a mechanism used to clamp the electrode wire head. A normally closed wire clamp can be directly formed by spring compression, or a lever mechanism and a spring can be combined to form a normally closed wire clamp, or a normally closed solenoid valve can be used to form a normally closed wire clamp, etc.

[0014] 2. In the above scheme, the "lower wire guide head of the machine tool" refers to the lower wire guide nozzle and lower main guide wheel mechanism of the machine tool.

[0015] 3. In the above scheme, the linear drive mechanism in the push-pull mechanism includes a chain, a chain guide, a sprocket and a drive motor, wherein:

[0016] The chain is an open-loop chain, that is, the head and tail of the chain are not connected to form a chain link. The chain is a roller chain composed of chain rollers, chain roller shafts and chain plates, wherein a chain roller at the head end of the chain serves as a guide wheel, and the chain roller shaft corresponding to the guide wheel serves as a push-pull traction point, which is traction-connected to the wire drawing trolley.

[0017] The chain guide has a T-shaped guide groove that can accommodate each chain roller and one side chain plate on the chain and can perform guiding cooperation. In the assembled state, the chain roller and one side chain plate of the chain are guided and cooperated with the T-shaped guide groove of the chain guide and can slide as a whole along the direction of the T-shaped guide groove. The chain guide is fixedly laid between the front end position and the rear end position of the lower wire feeding path relative to the lower wire arm of the machine tool.

[0018] The drive motor and the sprocket are positioned and mounted on a component relatively stationary to the lower line arm (28) of the machine tool, the drive motor is transmission-connected to the sprocket, and the sprocket is meshed with the chain.

[0019] Thus, a linear drive mechanism capable of pushing the wire drawing trolley forward or pulling it backward to move along the lower wire feeding path is formed by the chain guide rail, the open-loop chain, the sprocket and the drive motor.

[0020] 4. In the above scheme, the push-pull traction point is arranged at the front end of the chain, and the chain is traction-connected to the wire-drawing trolley at the push-pull traction point through a connecting piece.

[0021] 5. In the above scheme, an arc-shaped chain guide is provided in the meshing section between the chain and the sprocket, and the radius of the arc-shaped chain guide matches the radius of the sprocket, so that the chain can go around along the arc-shaped chain guide and naturally droop at the lower end outlet under the action of its own gravity.

[0022] 6. In the above scheme, a chain storage box capable of storing the chain is arranged below the naturally drooping chain, the horizontal cross-section of the box cavity of the chain storage box is a rectangular cross-section, the width of the rectangular cross-section is adapted to the width of the chain, the length of the rectangular cross-section is at least greater than the length of one section of the chain, and the box cavity has a depth capable of storing the chain in the naturally drooping direction of the chain. When the chain moves backward along the chain guide and droops naturally from the outlet at the lower end of the arc-shaped chain guide, under the action of the chain's gravity and its own flexibility and the constraint of the chain storage box (12), a part of the naturally drooping section of the chain is stacked in the chain storage box.

[0023] 7. In the above scheme, the linear drive mechanism in the push-pull mechanism adopts a pulley drive mechanism, a rope pulley drive mechanism, a gear rack drive mechanism, a screw nut pair drive mechanism or a gas-liquid cylinder drive mechanism.

[0024] 8. In the above scheme, the linear moving mechanism in the wire hooking mechanism is composed of a first wire hooking cylinder and a second wire hooking cylinder, the first wire hooking cylinder has a first extension end, the first extension end is fixed or positioned connected to the first wire hooking block, and the first extension end acts in the up and down direction. The second wire hooking cylinder has a second extension end, the second extension end is fixed or positioned connected to the second wire hooking block, and the second extension end acts in the up and down direction.

[0025] 9. In the above scheme, the first wire hooking surface and the second wire hooking surface are arc-shaped surfaces that bulge upward in the middle in the length direction of the electrode wire hooking and lifting section.

[0026] 10. In the above scheme, the wire hooking mechanism includes a wire blocking block, which is positioned and installed relative to the wire drum support or the wire drum slide of the machine tool. When the wire clamping and drawing trolley is in the rear end position of the lower wire feeding path, a wire blocking surface is provided on the wire blocking block facing downwards. The wire blocking block is located at a position of the electrode wire hooking and lifting section close to the front end of the wire clamping and drawing trolley. The wire blocking surface faces downwards and is directly opposite to the electrode wire of the hooking and lifting section. The wire blocking surface is an arc-shaped surface that bulges downwards in the middle in the length direction of the electrode wire hooking and lifting section.

[0027] 11. In the above scheme, a front end bracket is provided for the wire drawing trolley at the front end position of the lower wire feeding path, the front end bracket is fixedly positioned on a component that does not move relative to the machine tool column, and a guide surface and a positioning seat are provided on the front end bracket, which guide and position the wire drawing trolley entering the front end bracket. A rear end bracket is provided for the wire drawing trolley at the rear end position of the lower wire feeding path, the rear end bracket is fixedly positioned on a component that does not move relative to the machine tool column, and a guide surface and a positioning seat are provided on the rear end bracket, which guide, position and support the wire drawing trolley entering the rear end bracket.

[0028] 12. In the above scheme, a second contact is arranged on the positioning seat of the front end support, and an exposed first contact or first sensing point is arranged at the corresponding position of the wire clamping and drawing trolley for the second contact. The first contact or the first sensing point is connected with the contact or sensing point arranged relative to the electrode wire head inside the wire clamping and drawing trolley for detecting whether the electrode wire head is threaded into place. When the wire clamping and drawing trolley enters the positioning seat of the front end support for positioning, the second contact is connected with the first contact or the first sensing point, and the signal of whether the wire head is in place is transmitted to the automatic wire threading control system of the machine tool.

[0029] 13. In the above scheme, the front-end pressing mechanism is a front cylinder, which has a front extension end, and the front extension end is used as the front pressing output end. The rear-end pressing mechanism is a rear cylinder, which has a rear extension end, and the rear extension end is used as the rear pressing output end.

[0030] 14. In the above scheme, the front end pressing mechanism and the rear end pressing mechanism both adopt electromagnet, cam mechanism, lever mechanism or crank connecting rod mechanism.

[0031] Due to the application of the above scheme, the present invention has the following substantial characteristics and effects compared with the prior art:

[0032] 1. The present invention adopts a wire drawing and transmission method to convert the soft electrode wire into a relatively rigid wire, which is smoothly and reliably drawn from the wire guide head under the machine tool to the lower part of the wire drum and introduced into the wire clamp of the wire drum, thereby avoiding the defects of long-distance transmission of the soft electrode wire using a wire guide tube + a lower wire feeding mechanism + a gas-assisted wire feeding, such as the easy instability and bending of the soft electrode wire, the great difficulty in pushing the wire, and the easy clogging of the wire guide tube and other mechanisms by the viscous erosion produced by the electric spark cutting, resulting in the failure of wire threading, thereby improving the reliability of wire threading and ensuring the success rate of wire threading.

[0033] 2. The present invention ingeniously adopts a combination of a rigid and flexible open-loop chain and a chain guide to transport the wire drawing trolley. The chain does not make a closed cycle. When pushing and pulling the wire drawing trolley on the lower wire feeding path (drawing area), the rigidity of the chain in the chain guide is utilized to reliably complete the pushing and drawing tasks under the drive of the driving motor and the sprocket.

[0034] 3. After completing the wire drawing transmission, the chain and the wire drawing trolley of the present invention utilize the gravity and foldable flexibility of the chain to store them in a chain storage box outside the processing area. The drive motor and sprocket can also be arranged outside the processing area to avoid the adhesion of the processing eroded materials. The structure is simple, the operation is reliable, and it is easy to maintain.

[0035] 4. The wire hooking block and the wire blocking block of the wire hooking mechanism of the present invention have arc-shaped surfaces, which avoids the electrode wire from forming an inflection point and bending and damaging the electrode wire when the electrode wire is hooked and pulled into the wire clamp of the wire drum, so that the subsequent automatic wire threading can proceed smoothly, thereby improving the reliability and success rate of automatic wire threading.

[0036] 5. The present invention sets up an electrode wire head position detection link to detect the position of the electrode wire head entering the wire clamping and drawing trolley, accurately judge the position of the electrode wire head, and the wire drawing length can be digitally controlled, which significantly improves the control level of the automatic wire threading system on the length and position of the threaded electrode wire, and improves the reliability and success rate of automatic wire threading. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Attached Figure 1 It is a cross-sectional view of the automatic wire feeding mechanism according to an embodiment of the present invention. Figure 1 Three wire drawing trolleys 1 are shown in the figure, but there is actually only one wire drawing trolley 1. Figure 1The three wire drawing trolleys 1 in the figure indicate that the same wire drawing trolley 1 is in different positions at different times, wherein, from left to right, the first one indicates that the wire drawing trolley 1 is in the front position, the second one indicates that the wire drawing trolley 1 is in the middle position, and the third one indicates that the wire drawing trolley 1 is in the rear position.

[0038] Attached Figure 2 for Figure 1 An enlarged view of point A when the wire drawing trolley is in the front end position.

[0039] Attached Figure 3 for Figure 1 An enlarged view of point B when the wire drawing trolley is in the rear end position.

[0040] In the above figures: 1. Wire drawing trolley; 2. Chain guide; 3. Chain; 4. Sprocket; 5. Driving motor; 6. First contact; 8. Lower wire guide head; 9. Electrode wire; 10. Wire drum; 11. Arc-shaped chain guide; 12. Chain storage box; 13. Top pressure point; 14. First wire hooking block; 15. First wire hooking cylinder; 16. Second wire hooking block; 17. Second wire hooking cylinder; 18. Wire blocking block; 19. Front support; 20. Rear support; 21. Second contact; 22. Front cylinder; 23. Rear cylinder; 24. Wire drum wire clamp; 25. Wire drum support; 26. Lower wire guide nozzle; 27. Lower main guide wheel; 28. Lower wire arm. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0042] Embodiment: An automatic wire feeding mechanism for an automatic wire threading electric spark wire cutting machine tool

[0043] like Figure 1-3 As shown, the automatic wire feeding mechanism includes a push-pull mechanism, a wire drawing trolley 1 (see Figure 1-3 ), wire hook mechanism and trolley wire clamp opening mechanism.

[0044] In order to better describe the present invention, it is defined that the lower wire guide head 8 (see Figure 1 and Figure 2 ) The wire head position of the electrode wire 9 passing horizontally through the wire drum 10 is the lower wire feeding path of the machine tool, the wire head position is the front end position, and the position below the wire drum is the rear end position (see Figure 1 In the present invention, the lower wire guide head 8 of the machine tool refers to the lower wire guide nozzle 26 and the lower main guide wheel 27 mechanism of the machine tool (see Figure 1 and Figure 2 The lower wire guide head 8 is fixedly mounted on the front end of the lower wire arm 28 (see Figure 1 ), the lower line arm 28 is fixedly mounted on the vertical beam of the machine tool.

[0045] The push-pull mechanism is a device for pushing and pulling the wire clamping and drawing trolley 1 (see Figure 1 ) mechanism, which consists of a guide rail and a linear drive mechanism, the guide rail and the linear drive mechanism are positioned and installed on a member that is relatively stationary with the lower wire arm 28 of the machine tool, and a moving structure that is compatible with the guide rail is provided on the wire drawing trolley 1, and the wire drawing trolley 1 moves and cooperates with the guide rail through the moving structure, so that the wire drawing trolley 1 can reciprocate along the guide rail under the constraint of the guide rail, and the linear drive mechanism has a push-pull action end, and in the working state, the linear drive mechanism drives the wire drawing trolley 1 to push forward or pull backward between the front end position and the rear end position through the push-pull action end. In the present invention, the guide rail is a restrictive guide rail used to provide the wire drawing trolley 1 with reciprocating motion between the front end position and the rear end position of the lower wire feeding path. The guide rail can be a single-track guide rail or a double-track guide rail. Generally speaking, it is best to use a straight track as the guide track, but in theory it is not limited to this. A curved or arc track, or even a broken line track can be used. As long as the wire drawing trolley 1 can reciprocate between the front end position and the rear end position of the lower wire feeding path through the guide track, the purpose and effect of the present invention can be achieved. The moving structure refers to a moving part of the wire drawing trolley 1 that can be adapted to the guide track. The moving part can be a guide wheel, a guide slider or a guide sleeve, etc. that can provide moving matching. This is generally understood and known by those skilled in the art.

[0046] In this embodiment, the linear drive mechanism in the push-pull mechanism includes a chain 3, a chain guide 2, a sprocket 4 and a drive motor 5 (see Figure 1 ),in:

[0047] The chain 3 is an open-loop chain, i.e., the head and tail of the chain 3 are not connected to form a chain link (see Figure 1 ), the chain 3 is a roller chain composed of chain rollers, chain roller shafts and chain plates, wherein a chain roller at the head end of the chain 3 is used as a guide wheel, and the chain roller shaft corresponding to the guide wheel is used as a push-pull traction point, which is traction-connected with the wire drawing trolley 1. The push-pull traction point is located at the front end of the chain 3 (see Figure 1 ), the chain 3 is traction-connected to the wire drawing trolley 1 at the push-pull traction point through a connecting piece (pin shaft, not shown in the figure).

[0048] The chain guide rail 2 has a T-shaped guide groove that can accommodate each chain roller and one side chain plate on the chain 3 and can be guided and matched. In the assembled state, the chain roller and one side chain plate of the chain 3 are guided and matched with the T-shaped guide groove of the chain guide rail 2 and can slide as a whole along the direction of the T-shaped guide groove (see Figure 1), the chain guide rail 2 is fixedly laid between the front end position and the rear end position of the lower wire feeding path relative to the lower wire arm 28 of the machine tool.

[0049] The drive motor 5 and the sprocket 4 are positioned and installed on a relatively stationary component with respect to the lower line arm 28 of the machine tool. The drive motor 5 is connected to the sprocket 4 in a transmission manner, and the sprocket 4 is meshed with the chain 3 (see Figure 3 ).

[0050] Thus, the chain guide rail 2, the open-loop chain 3, the sprocket 4 and the drive motor 5 cooperate to form a linear drive mechanism that can push forward or pull backward the wire drawing trolley 1 to move along the lower wire feeding path.

[0051] A front position travel switch (not shown in the figure) and a rear position travel switch (not shown in the figure) are correspondingly provided for the front position and the rear end position, and a first contact (not shown in the figure) capable of measuring the walking position is provided on the body of the wire drawing trolley 1.

[0052] The front position travel switch is arranged corresponding to the front end position of the lower wire feeding path, and a front position contact is provided on the front position travel switch. The front position contact and the first contact of the wire drawing trolley 1 are in contact cooperation or non-contact cooperation working states on the path where the wire drawing trolley 1 runs along the lower wire feeding path.

[0053] The rear position travel switch is arranged corresponding to the rear end position of the lower wire feeding path, and a rear position contact is provided on the rear position travel switch. The rear position contact and the first contact of the wire drawing trolley 1 are in contact cooperation or non-contact cooperation working states on the path where the wire drawing trolley 1 runs along the lower wire feeding path.

[0054] In this embodiment, a circular arc chain guide 11 is provided in the meshing section between the chain 3 and the sprocket 4 (see Figure 3 ), the radius of the arc-shaped chain guide 11 matches the radius of the sprocket 4, so that the chain 3 can go around the arc-shaped chain guide 11 and droop naturally under the action of its own gravity at the lower end outlet (see Figure 1 and Figure 3 ).

[0055] A chain storage box 12 (see FIG. 1 ) for storing the chain 3 is provided below the naturally drooping chain 3. Figure 1 and Figure 3 ), the horizontal cross-section of the box cavity of the chain storage box 12 is a rectangular cross-section, the width of the rectangular cross-section is adapted to the width of the chain 3, the length of the rectangular cross-section is at least greater than the length of one section of the chain, and the box cavity has a depth capable of storing the chain 3 in the natural sagging direction of the chain 3. When the chain 3 moves backward along the chain guide rail 2 and naturally droops from the lower end outlet of the arc-shaped chain guide rail 11, under the action of the gravity and self-flexibility of the chain 3 and the constraint of the chain storage box 12, a part of the naturally drooping section of the chain 3 is stacked in the chain storage box 12 (see Figure 1 right).

[0056] The above describes in detail the best embodiment of the push-pull mechanism in the present invention, but the present invention is not limited thereto, and the linear drive mechanism in the push-pull mechanism can also adopt a pulley drive mechanism, a rope pulley drive mechanism, a gear rack drive mechanism, a screw nut pair drive mechanism or a gas-liquid cylinder drive mechanism, which can be understood by those skilled in the art.

[0057] The wire drawing trolley 1 (see Figure 1 ) is a clamp used to clamp the electrode wire 9 and feed the wire on the lower wire feeding path. The clamp is provided with a clamping mechanism (not shown in the figure) for clamping the electrode wire 9 and a spring (not shown in the figure) for forcing the clamping mechanism to be in a normally closed state. In the assembled state, the spring acts on the clamping mechanism to make the clamping mouth of the clamping mechanism in a normally closed state, thereby forming a normally closed wire clamp. The normally closed wire clamp refers to a wire clamp that is always in a closed clamping state without external force intervention. Normally closed is relative to normally open. The wire clamp is a mechanism used to clamp the electrode wire head. A normally closed wire clamp can be directly formed by spring compression, or a normally closed wire clamp can be formed by a lever mechanism and a spring combination, or a normally closed wire clamp can be formed by a normally closed solenoid valve, etc. For example, in this embodiment, the normally closed wire clamp formed by a lever mechanism and a spring combination is composed of a main lever and a spring. The lever is rotatably supported on the wire drawing trolley 1, one end of the lever is used as the clamping mouth of the wire clamp, and the spring acts on the other end of the lever to make the clamping mouth of the wire clamp in a normally closed state. This normally closed wire clamp is arranged on the wire drawing trolley 1 and belongs to a built-in normally closed wire clamp structure. In addition, a top pressure point 13 (see FIG. 1 ) for opening the clamping mechanism is provided on the normally closed wire clamp corresponding to the spring. Figure 2 and Figure 3 ), used to open the normally closed wire clamp.

[0058] The wire hooking mechanism is a wire hooking mechanism for hooking the electrode wire 9 from the bottom of the wire drum 10 into the wire drum wire clamp 24. The wire hooking mechanism includes a first wire hooking block 14 (see Figure 1 )、Second hook wire block 16 (see Figure 1 ) and a lifting mechanism, wherein the first wire hooking block 14 is located on one side of the wire drum 10, and the first wire hooking block 14 is provided with a first wire hooking surface facing upward, and the first wire hooking surface is located directly below the electrode wire 9 (see Figure 1 The second wire hooking block 16 is located at the other side of the wire drum 10, and the second wire hooking block 16 is provided with a second wire hooking surface facing upward, and the second wire hooking surface is located directly below the electrode wire 9 (see Figure 1The lifting mechanism is a linear moving mechanism controlled by the automatic wire threading system of the machine tool. The linear moving mechanism is positioned and installed relative to the wire tube support 25 or the wire tube carriage. The linear moving mechanism has a movable extension end, which is fixed or positioned with the first wire hook block 14 and the second wire hook block 16 respectively. The movable extension end moves up and down under the control of the automatic wire threading system of the machine tool.

[0059] In this embodiment, the linear moving mechanism in the wire hooking mechanism is composed of a first wire hooking cylinder 15 (see Figure 1 ) and the second hooking cylinder 17 (see Figure 1 ), the first wire hooking cylinder 15 has a first extension end, which is fixed or positioned connected to the first wire hooking block 14, and the first extension end acts in the up and down direction. The second wire hooking cylinder 17 has a second extension end, which is fixed or positioned connected to the second wire hooking block 16, and the second extension end acts in the up and down direction. In the present invention, in addition to the cylinder, the linear moving mechanism in the wire hooking mechanism can also adopt a hydraulic cylinder drive mechanism, a gear rack drive mechanism, a screw nut pair drive mechanism, a pulley drive mechanism, a lever drive mechanism or a cam drive mechanism, etc. This is understandable to those skilled in the art.

[0060] The wire hooking mechanism also includes a wire blocking block 18 (see Figure 1 The wire block 18 is positioned and installed relative to the wire drum support 25 or the wire drum carriage of the machine tool. When the wire drawing trolley 1 is in the rear end position of the lower wire feeding path, the wire block 18 is provided with a wire blocking surface facing downward. The wire block 18 is located at the position of the electrode wire 9 hooking section near the front end of the wire drawing trolley 1, and the wire blocking surface faces downward and directly faces the electrode wire 9 in the hooking section. The function of the wire block 18 is to prevent the electrode wire 9 between the electrode wire 9 clamped by the wire drawing trolley 1 and the lowest point of the wire blocking surface of the wire block 18 from being pulled up when the second wire hooking cylinder 17 goes up to hook the wire.

[0061] The first wire hooking surface and the second wire hooking surface are arc-shaped surfaces that bulge upward in the middle in the length direction of the hooking section of the electrode wire 9 (see Figure 1 The wire blocking surface is an arc-shaped surface that bulges downward in the middle in the length direction of the hook-up section of the electrode wire 9 (see Figure 1 The wire hooking surface and the wire blocking surface are designed to be arc-shaped surfaces, the purpose of which is to avoid forming an inflection point on the hooked and blocked electrode wire 9 and bending and damaging the electrode wire 9 during the process of hooking and blocking the wire, so that the subsequent automatic wire threading can proceed smoothly.

[0062] The trolley wire clamp opening mechanism is a pressing mechanism capable of opening the normally closed wire clamp on the wire drawing trolley 1. The pressing mechanism is composed of two sets of front pressing mechanism and rear pressing mechanism. The front pressing mechanism is positioned and installed at the front position and is externally arranged relative to the pressing point 13 of the normally closed wire clamp of the wire drawing trolley 1. The rear pressing mechanism is positioned and installed at the rear position and is externally arranged relative to the pressing point 13 of the normally closed wire clamp of the wire drawing trolley 1. The front pressing mechanism is provided with a front pressing output end controlled by the automatic wire threading system of the machine tool. In the working state, when the wire drawing trolley 1 runs to the front position, the front pressing output end extends and acts on the pressing point 13 of the normally closed wire clamp under the control of the automatic wire threading system of the machine tool to overcome the spring force to open the clamping mechanism on the wire drawing trolley 1. When the wire head of the electrode wire 9 is fed into the clamping mechanism, the front pressing output end retracts to complete the wire clamping. The rear end pressing mechanism is provided with a rear pressing output end controlled by the automatic wire threading system of the machine tool. In the working state, when the wire drawing trolley 1 runs to the rear end position and the wire hooking mechanism hooks the electrode wire 9 from the bottom of the wire drum 10 into the wire drum wire clamp 24, the rear pressing output end extends out under the control of the automatic wire threading system of the machine tool and acts on the normally closed wire clamp pressing point 13 to overcome the spring force to open the clamping mechanism on the wire drawing trolley 1 and complete the wire loosening. In this embodiment, the front end pressing mechanism is a front position cylinder 22 (see Figure 1 and Figure 2 ), the front cylinder 22 has a front extension end, which serves as the front pressure output end. When the wire drawing trolley 1 enters the front bracket 19 positioning seat, the front extension end of the front cylinder 22 acts on the top pressure point 13 of the normally closed wire clamp of the wire drawing trolley 1, and forces the normally closed wire clamp to open the clamping opening to thread the wire. The rear end pressure mechanism is the rear cylinder 23 (see Figure 1 and Figure 3 ), the rear cylinder 23 has a rear extension end, which serves as a rear pressure output end. When the wire drawing trolley 1 enters the rear end support seat 20 and is positioned, the rear extension end of the rear cylinder 23 acts on the normally closed wire clamp pressure point 13 of the wire drawing trolley 1, and forces the normally closed wire clamp to open the clamping mouth to release the wire. The front end pressure mechanism and the rear end pressure mechanism in the present invention are not limited to cylinders, and can also adopt electromagnets, cam mechanisms, lever mechanisms or crank connecting rod mechanisms.

[0063] In this embodiment, a front end bracket 19 is provided for the wire drawing trolley 1 at the front end position of the lower wire feeding path (see Figure 1 and Figure 2), the front end support 19 is fixedly positioned on a member that does not move relative to the machine column (in this embodiment, the front end support 19 is fixedly connected to the lower wire arm), and the front end support 19 is provided with a guide surface and a positioning seat, which guides, positions and supports the wire drawing trolley 1 entering the front end support 19, and also supports the wire drawing trolley 1 when the front cylinder 22 presses down on the normally closed wire clamp. A rear end support 20 is provided for the wire drawing trolley 1 at the rear end position of the lower wire feeding path (see Figure 1 and Figure 3 ), the rear end support 20 is fixedly positioned on a component that has no relative motion with the machine tool column (in the present embodiment, the rear end support 20 is fixedly connected to the machine tool bed or the base of the wire transport mechanism), and a guiding surface and a positioning seat are provided on the rear end support 20, which play a guiding, positioning and supporting role for the wire clamping and drawing trolley 1 entering the rear end support 20, and in addition, when the rear position cylinder 23 presses down on the normally closed wire clamp, the wire clamping and drawing trolley 1 plays a supporting role.

[0064] A second contact 21 is provided on the positioning seat of the front end bracket 19 (see Figure 2 ), an exposed first contact 6 is provided at a corresponding position of the wire drawing carriage 1 for the second contact 21 (see Figure 2 ) or the first sensing point, the first contact 6 or the first sensing point is connected to the contact or sensing point set relative to the electrode wire 9 inside the wire drawing trolley 1 for detecting whether the wire head of the electrode wire 9 is in place, and when the wire drawing trolley 1 enters the front end support seat 19 and is positioned, the second contact 21 is connected to the first contact 6 or the first sensing point, and transmits the signal of whether the wire head is in place to the automatic wire threading control system of the machine tool.

[0065] The working process of the automatic wire feeding mechanism of the present invention is as follows:

[0066] See also Figure 1 Under the control of the automatic wire threading system of the machine tool, the driving motor 5 drives the chain 3 to move from right to left along the chain guide 2 through the sprocket 4, and the chain 3 drives the wire drawing trolley 1 to move from right to left through the push-pull traction point until it enters the front end bracket 19 and reaches the front end position (see Figure 1Left part), after being in place, the wire guide hole at the front end of the wire drawing trolley 1 is aligned with the electrode wire outlet on the lower right side of the lower wire guide head 8. At this time, the front position travel switch sends a signal of being in place, and then the front position cylinder 22 presses down to open the clamping port of the normally closed clamping mechanism on the wire drawing trolley 1, and then the wire head of the electrode wire 9 is sent out from the right wire guide hole of the lower wire guide head 8 of the machine tool, and enters the wire guide hole and clamping port at the front end of the wire drawing trolley 1, and then the wire head detection contact inside the wire drawing trolley 1 touches the wire head, and sends a wire head in place signal through the second contact 21, and then the front position cylinder 22 returns to its original position, and the normally closed clamping mechanism automatically closes the clamping port and clamps the wire head, and then the driving motor 5 drives the wire drawing trolley 1 to do wire drawing movement (from left to right) along the lower wire feeding path from the front position to the rear position through the sprocket 4 and the chain 3, until it enters the rear end support 20 and reaches the rear end position (see Figure 1 The wire-hooking block is on the right side (at this time, the wire-hooking block is below the electrode wire 9), then the rear-position stroke switch sends an in-position signal, and then the machine tool controls the wire drum 10 and the wire drum slide to move, so that the wire drum wire clamp 24 is directly above the electrode wire 9, and the wire-hooking surfaces of the two wire-hooking blocks are below the electrode wire 9, and the wire-blocking surface of the wire-blocking block 18 is on the main side of the electrode wire 9, then the wire drum wire clamp 24 is opened, and the two wire-hooking blocks (the first wire-hooking block 14 and the second wire-hooking block 16) are driven upward by two cylinders (the first wire-hooking cylinder 15 and the second wire-hooking cylinder 17), and the wire-hooking surfaces on the two wire-hooking blocks hook the electrode wire 9 upward, so that the electrode wire 9 enters the wire clamping groove of the wire drum wire clamp 24, and then the rear-position cylinder 23 presses down to open the clamping port of the normally closed clamping mechanism on the wire-drawing trolley 1, and the automatic wire threading system of the machine tool draws the wire head in the wire-drawing trolley 1 back into the wire drum wire clamp 24, and then the wire drum wire clamp 24 is locked, and the wire head is clamped to complete the lower wire drawing task.

[0067] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic wire feeding mechanism for an automatic wire threading electric spark wire cutting machine, characterized in that: It comprises a push-pull mechanism, a wire-clamping trolley (1), a wire-hooking mechanism and a trolley wire-clamp opening mechanism; The position of the wire head of the electrode wire (9) passing horizontally through the lower wire guide head (8) of the machine tool to the position below the wire drum (10) is defined as the lower wire feeding path of the machine tool, the wire head position is the front end position, and the position below the wire drum (10) is the rear end position; The push-pull mechanism is a mechanism for pushing and pulling the wire-drawing trolley (1) on the lower wire feeding path, and the mechanism is composed of a guide rail and a linear drive mechanism, and the guide rail and the linear drive mechanism are positioned and installed on a member that is relatively stationary with the lower wire arm (28) of the machine tool, and a moving structure that is compatible with the guide rail is provided on the wire-drawing trolley (1), and the wire-drawing trolley (1) moves with the guide rail through the moving structure, so that the wire-drawing trolley (1) can reciprocate along the guide rail under the constraint of the guide rail, and the linear drive mechanism has a push-pull action end, and in the working state, the linear drive mechanism drives the wire-drawing trolley (1) to push forward or pull backward between the front end position and the rear end position through the push-pull action end; The wire drawing trolley (1) is a clamp used for clamping the wire head of the electrode wire (9) and feeding the wire on the lower wire feeding path. The clamp is provided with a clamping mechanism for clamping the wire head of the electrode wire (9) and a spring for forcing the clamping mechanism to be in a normally closed state. In the assembled state, the spring acts on the clamping mechanism to make the clamping mouth of the clamping mechanism in a normally closed state, thereby forming a normally closed wire clamp; the normally closed wire clamp is provided with a top pressure point (13) corresponding to the spring for opening the clamping mechanism; The wire hooking mechanism is a wire hooking mechanism used to hook the electrode wire (9) from the bottom of the wire drum (10) into the wire drum wire clamp (24), and the wire hooking mechanism comprises a first wire hooking block (14), a second wire hooking block (16) and a lifting mechanism, wherein the first wire hooking block (14) is located on one side of the wire drum (10), and a first wire hooking surface is provided on the first wire hooking block (14) facing upward, and the first wire hooking surface is located directly below the electrode wire (9); the second wire hooking block (16) is located on the other side of the wire drum (10), and the second wire hooking block (16) is provided on the second side of the wire drum (10). The second wire hooking block (16) is provided with a second wire hooking surface facing upward, and the second wire hooking surface is located directly below the electrode wire (9); the lifting mechanism is a linear moving mechanism controlled by the automatic wire threading system of the machine tool, the linear moving mechanism is positioned and installed relative to the wire drum support (25) or the wire drum drag plate, and the linear moving mechanism has a movable extension end, which is fixed or positionally connected to the first wire hooking block (14) and the second wire hooking block (16) respectively, and the movable extension end moves up and down under the control of the automatic wire threading system of the machine tool; The trolley wire clamp opening mechanism is a pressing mechanism capable of opening the normally closed wire clamp on the wire drawing trolley (1), the pressing mechanism consisting of a front pressing mechanism and a rear pressing mechanism. The front pressing mechanism is positioned and installed at the front position and is externally arranged relative to the pressing point (13) of the normally closed wire clamp of the wire drawing trolley (1), and the rear pressing mechanism is positioned and installed at the rear position and is externally arranged relative to the pressing point (13) of the normally closed wire clamp of the wire drawing trolley (1). The front pressing mechanism is provided with a front pressing output end controlled by the automatic wire threading system of the machine tool. In the working state, when the wire drawing trolley (1) moves to the front position, the front pressing output end extends and acts under the control of the automatic wire threading system of the machine tool. At the top pressure point (13) of the normally closed wire clamp, the clamping mechanism on the wire clamping trolley (1) is opened to overcome the spring force, and when the wire head of the electrode wire (9) is fed into the clamping mechanism, the front top pressure output end is retracted to complete the wire clamping; the rear end top pressure mechanism is provided with a rear top pressure output end controlled by the automatic wire threading system of the machine tool. In the working state, when the wire clamping trolley (1) runs to the rear end position and the wire hooking mechanism hooks the electrode wire (9) from the bottom of the wire drum (10) into the wire drum wire clamp (24), the rear top pressure output end is extended under the control of the automatic wire threading system of the machine tool and acts on the top pressure point (13) of the normally closed wire clamp to overcome the spring force to open the clamping mechanism on the wire clamping trolley (1) to complete the wire loosening.

2. The automatic wire feeding mechanism according to claim 1 is characterized in that: The linear drive mechanism in the push-pull mechanism comprises a chain (3), a chain guide rail (2), a sprocket (4) and a drive motor (5), wherein: The chain (3) is an open-loop chain, that is, the head and tail of the chain (3) are not connected to form a chain link. The chain (3) is a roller chain composed of a chain roller, a chain roller shaft and a chain plate, wherein a chain roller at the head end of the chain (3) serves as a guide wheel, and the chain roller shaft corresponding to the guide wheel serves as a push-pull traction point, which is traction-connected to the wire drawing trolley (1); The chain guide rail (2) has a T-shaped guide groove capable of accommodating each chain roller and a chain plate on a side of the chain (3) and capable of guiding and matching. In an assembled state, the chain roller and the chain plate on a side of the chain (3) are guided and matched with the T-shaped guide groove of the chain guide rail (2) and can slide as a whole along the direction of the T-shaped guide groove. The chain guide rail (2) is fixedly laid between the front end position and the rear end position of the lower wire feeding path relative to the lower wire arm (28) of the machine tool; The drive motor (5) and the sprocket (4) are positioned and mounted on a component relatively stationary to the lower line arm (28) of the machine tool, the drive motor (5) is transmission-connected to the sprocket (4), and the sprocket (4) is meshed with the chain (3); Thus, a linear drive mechanism capable of pushing the wire drawing trolley (1) forward or pulling it backward to move along the lower wire feeding path is formed by the cooperation of the chain guide rail (2), the open-loop chain (3), the sprocket (4) and the drive motor (5).

3. The automatic wire feeding mechanism according to claim 2 is characterized in that: The push-pull traction point is arranged at the front end of the chain (3), and the chain (3) is traction-connected to the wire drawing trolley (1) at the push-pull traction point via a connecting piece.

4. The automatic wire feeding mechanism according to claim 2 is characterized in that: An arc-shaped chain guide rail (11) is provided in the meshing section between the chain (3) and the sprocket (4), and the radius of the arc-shaped chain guide rail (11) matches the radius of the sprocket (4), so that the chain (3) can go around along the arc-shaped chain guide rail (11) and naturally droop at the lower end outlet under the action of its own gravity.

5. The automatic wire feeding mechanism according to claim 4 is characterized in that: A chain storage box (12) capable of storing the chain (3) is arranged below the naturally drooping chain (3); the horizontal cross-section of the box cavity of the chain storage box (12) is a rectangular cross-section; the width of the rectangular cross-section matches the width of the chain (3); the length of the rectangular cross-section is at least greater than the length of one section of the chain; the box cavity has a depth capable of storing the chain (3) in the naturally drooping direction of the chain (3); when the chain (3) moves backward along the chain guide rail (2) and droops naturally from the lower end outlet of the arc-shaped chain guide rail (11), under the action of the gravity and self-flexibility of the chain (3) and the constraint of the chain storage box (12), a part of the naturally drooping section of the chain (3) is stacked in the chain storage box (12).

6. The automatic wire feeding mechanism according to claim 1 is characterized in that: The linear drive mechanism in the push-pull mechanism adopts a pulley drive mechanism, a rope pulley drive mechanism, a gear rack drive mechanism, a screw nut pair drive mechanism or a gas-liquid cylinder drive mechanism.

7. The automatic wire feeding mechanism according to claim 1, characterized in that: The linear moving mechanism in the wire hooking mechanism is composed of a first wire hooking cylinder (15) and a second wire hooking cylinder (17). The first wire hooking cylinder (15) has a first protruding end, which is fixedly or positionally connected to the first wire hooking block (14), and the first protruding end acts in the up-down direction; the second wire hooking cylinder (17) has a second protruding end, which is fixedly or positionally connected to the second wire hooking block (16), and the second protruding end acts in the up-down direction.

8. The automatic wire feeding mechanism according to claim 1, characterized in that: The first wire hooking surface and the second wire hooking surface are arc-shaped surfaces that bulge upward in the middle in the length direction of the hooking section of the electrode wire (9).

9. The automatic wire feeding mechanism according to claim 1, characterized in that: The wire hooking mechanism comprises a wire blocking block (18), the wire blocking block (18) is positioned and installed relative to the machine tool wire drum support (25) or the wire drum drag plate, when the wire clamping and drawing trolley (1) is in the rear end position of the lower wire feeding path, the wire blocking block (18) is provided with a wire blocking surface facing downward, the wire blocking block (18) is located at a position of the hooking and lifting section of the electrode wire (9) close to the front end of the wire clamping and drawing trolley (1), the wire blocking surface faces downward and directly faces the electrode wire (9) of the hooking and lifting section, and the wire blocking surface is an arc-shaped surface that bulges downward in the middle in the length direction of the hooking and lifting section of the electrode wire (9).

10. The automatic wire feeding mechanism according to claim 1, characterized in that: A front end support seat (19) is provided at the front end position of the lower wire feeding path for the wire drawing trolley (1), the front end support seat (19) is fixedly positioned on a component that does not move relative to the machine tool column, and a guide surface and a positioning seat are provided on the front end support seat (19), which guide and position the wire drawing trolley (1) entering the front end support seat (19); a rear end support seat (20) is provided at the rear end position of the lower wire feeding path for the wire drawing trolley (1), the rear end support seat (20) is fixedly positioned on a component that does not move relative to the machine tool column, and a guide surface and a positioning seat are provided on the rear end support seat (20), which guide, position and support the wire drawing trolley (1) entering the rear end support seat (20).

11. The automatic wire feeding mechanism according to claim 10, characterized in that: A second contact (21) is arranged on the positioning seat of the front end support seat (19), and an exposed first contact (6) or a first sensing point is arranged at a corresponding position of the wire drawing carriage (1) for the second contact (21). The first contact (6) or the first sensing point is connected to a contact or sensing point arranged on the wire head of the electrode wire (9) inside the wire drawing carriage (1) for detecting whether the wire head of the electrode wire (9) is threaded into place. When the wire drawing carriage (1) enters the positioning seat of the front end support seat (19) for positioning, the second contact (21) is connected to the first contact (6) or the first sensing point, and transmits a signal indicating whether the wire head is in place to the automatic threading control system of the machine tool.

12. The automatic wire feeding mechanism according to claim 1, characterized in that: The front-end pressing mechanism is a front cylinder (22), which has a front extension end, and the front extension end serves as a front pressing output end; the rear-end pressing mechanism is a rear cylinder (23), which has a rear extension end, and the rear extension end serves as a rear pressing output end.

13. The automatic wire feeding mechanism according to claim 1, characterized in that: The front end pressing mechanism and the rear end pressing mechanism both adopt electromagnet, cam mechanism, lever mechanism or crank connecting rod mechanism.

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