Device and method for adjusting distance between jaws of skin stretcher

Abstract

The invention belongs to the technical field of stretch forming equipment, and particularly provides a skin stretcher jaw distance adjusting device and method.The skin stretcher jaw distance adjusting device comprises four adjusting units, the four adjusting units are symmetrically arranged front, back, left and right, and each adjusting unit comprises a moving cylinder, a fixed seat, a moving seat, a rack and a locking mechanism. The problems that due to the fact that the stroke of an existing moving cylinder is too large, the operation space of the stretcher is enlarged, misoperation is prone to being caused, the danger degree of the stretcher is increased, the safety risk is large, and the efficiency of a whole hydraulic system is reduced are solved. The stroke of the moving cylinder is only less than 1 / 3 of the stroke of the moving cylinder of the stretcher for adjusting the distance between the jaws of the stretcher by virtue of the stroke of the moving cylinder, so that all problems caused by overlarge stroke of the moving cylinder are avoided, and the moving cylinder has the characteristics of high working efficiency, long service life and convenience in maintenance.

Description

Technical Field

[0001] The invention belongs to the technical field of sheet metal parts processing, and particularly relates to a device and method for adjusting the distance between jaws of a skin stretching machine. Background Art

[0002] Skin stretching machines are key equipment for producing sheet metal components such as aircraft skins. With the rapid advancement of aviation technology and the increasing performance requirements of modern aircraft, the shapes of skin parts are becoming increasingly complex, with increasingly stringent requirements for dimensional accuracy and surface finish. Skin parts are characterized by a wide variety of products, small batch sizes, and large, complex structures. In actual use, skin stretching machines require increasingly frequent adjustments to the jaw spacing based on the size and shape of the skin parts being formed. Existing longitudinal skin stretching machines have a maximum jaw spacing of 12 meters, and the stretching cylinder has a 1-meter operating stroke. If the stretching machine jaw spacing were to be adjusted solely by the cylinder stroke, the cylinder stroke would have to be at least 4.5 meters. This excessive cylinder stroke increases the operating space of the stretching machine, making it prone to misoperation and increasing the danger level of the stretching machine, presenting unnecessary safety risks to production. Furthermore, the excessive stroke increases the range of motion of the cylinder, which in turn increases friction between internal components and worsens mechanical wear. Furthermore, the prolonged cylinder operation time reduces the efficiency of the entire hydraulic system. Summary of the Invention

[0003] The present invention provides a device and method for adjusting the distance between the jaws of a skin stretching machine. The first purpose is to overcome the problem in the prior art that a moving cylinder is used to adjust the distance between the jaws of a stretching machine, where the stroke of the moving cylinder is too large, resulting in an increase in the operating space of the stretching machine, which is prone to misoperation, increases the danger level of the stretching machine, and brings unnecessary safety risks to production; the second purpose is to overcome the problem in the prior art that the stroke of the moving cylinder is too large, increases the range of motion of the moving cylinder and the friction between the internal components of the moving cylinder, aggravates mechanical losses, and causes excessively long motion time of the moving cylinder, thereby reducing the efficiency of the entire hydraulic system.

[0004] To this end, the present invention provides a device for adjusting the distance between the jaws of a skin stretching machine, comprising four adjustment units, which are symmetrically arranged front to back and left to right. The adjustment units include a movable cylinder, a fixed seat, a movable seat, a frame and a locking mechanism. In the adjustment unit on the left, the top of the frame is connected to the fixed seat and the movable seat in sequence from left to right, the movable cylinder is connected to the fixed seat on the right, and the power output end of the movable cylinder passes through the fixed seat and is connected to the left end of the movable seat, and the fixed seat is connected to the frame through a locking mechanism.

[0005] Preferably, a guide rail is provided on the upper surface of the frame, and the fixed seat and the movable seat are both installed on the guide rail.

[0006] Preferably, the locking mechanism includes two sets of locking units and pins, the two sets of locking units are connected in the fixing seat, and the two sets of locking units are symmetrically arranged front to back, and the pins are connected between the power output ends of the two sets of locking units.

[0007] Preferably, the locking unit includes a locking cylinder and an articulated seat, the fixed seat is connected to the locking cylinder via the articulated seat, and the upper ends of the pin shafts are connected between the power output ends of the two locking cylinders.

[0008] Preferably, the frame includes an upper support plate and a support body, the upper side of the support body is connected to the upper support plate, and the upper side of the upper support plate is connected to the guide rail.

[0009] Preferably, a plurality of positioning holes are provided on the upper support plate, and the plurality of positioning holes are located on the guide rail and are spaced apart along the direction of the guide rail.

[0010] Preferably, the distance between two adjacent positioning holes among the plurality of positioning holes is equal to the stroke of the moving cylinder.

[0011] Preferably, a hole is provided on the bottom of the fixing seat.

[0012] Preferably, the moving cylinder adopts a moving cylinder with a piston rod, and the piston rod of the moving cylinder passes through the fixed seat and is connected to the left end of the moving seat; the locking cylinder adopts a locking cylinder with a piston rod, and the piston rods of the two locking cylinders are connected to the upper ends of the pin shafts.

[0013] A method for adjusting the distance between jaws of a skin stretching machine comprises the following steps: S1. The four adjustment units are symmetrically arranged front and back and left and right. The four adjustment units are divided into two groups, the movable bases of each group of adjustment units are connected to the jaws of the stretching machine through a bracket; in the initial state of the skin stretching machine, the locking mechanism is locked on the frame, and the distance between the jaws of the stretching machine between the two groups of adjustment units is at its maximum; S2. When the distance between the jaws of the stretching machine between the two sets of adjustment units needs to be reduced, the power output end of the mobile cylinder extends to push the movable seat to move toward the middle until the power output end of the mobile cylinder is fully extended and stops, the pin is pulled out from the positioning hole on the frame, the locking mechanism is unlocked from the frame, and then the power output end of the mobile cylinder retracts. The fixed seat moves toward the middle under the push of the power output end of the mobile cylinder until the power output end of the mobile cylinder is fully retracted and stops, the pin is inserted into the positioning hole on the frame, and the locking mechanism is locked on the frame again, completing the reduction of the target distance between the jaws of the stretching machine; S3. When it is necessary to further reduce the distance between the jaws of the stretching machine between the two groups of adjustment units, repeat the above step S2 until the distance between the jaws of the stretching machine between the two groups of adjustment units is reduced to the target position, completing the reduction adjustment of the target distance between the jaws of the stretching machine between the two groups of adjustment units.

[0014] Beneficial effects of the present invention: 1. The present invention provides a device and method for adjusting the distance between the jaws of a skin stretching machine. The four adjusting units are symmetrically arranged front to back and left to right. The adjusting units include a moving cylinder, a fixed seat, a moving seat, a frame and a locking mechanism. The four adjusting units are divided into two groups on the left and right. The moving seats of the adjusting units in each group are connected to the jaws of the stretching machine through a bracket. When it is necessary to reduce the distance between the jaws of the stretching machine between the two groups of adjusting units, the power output end of the moving cylinder extends to push the moving seat to move toward the middle until the power output end of the moving cylinder is fully extended and stops. The pin shaft is pulled out from the positioning hole on the frame, and the locking mechanism is unlocked from the frame. Then the power output end of the moving cylinder contracts, and the fixed seat moves toward the middle under the push of the power output end of the moving cylinder until the power output end of the moving cylinder is fully retracted and stops. The pin shaft is inserted into the positioning hole on the frame, and the locking mechanism is locked on the frame again to complete the reduction of the target distance between the jaws of the stretching machine. Through the cooperation of the moving cylinder, locking mechanism, fixed seat and frame, the distance between the jaws of the skin stretching machine can be adjusted, which can adapt to the production of skin parts of different sizes and has the advantages of convenient adjustment, stability and reliability; the target distance between the jaws of the stretching machine between the two groups of adjustment units is adjusted by gradually reducing the distance through the cooperation of the moving cylinder, locking mechanism, fixed seat and frame. Compared with relying entirely on the stroke of the moving cylinder to adjust the distance between the jaws of the stretching machine, the stroke of the moving cylinder of the present invention is only less than 1 / 3 of the stroke of the moving cylinder of the stretching machine that relies entirely on the stroke of the moving cylinder to adjust the distance between the jaws of the stretching machine, avoiding all problems caused by excessive stroke of the moving cylinder, and having the characteristics of high work efficiency, long service life and easy maintenance.

[0015] 2. The present invention provides a device and method for adjusting the distance between the jaws of a skin stretching machine. A guide rail is provided on the frame, and both the fixed seat and the movable seat are connected to the guide rail. The structure is simple, and the fixed seat and the movable seat can be easily moved as needed.

[0016] 3. The present invention provides a device and method for adjusting the distance between the jaws of a skin stretching machine. A pin shaft is connected between the power output ends of two groups of locking units. The locking unit drives the pin shaft to move downward, so that the pin shaft is inserted into the positioning hole on the frame, thereby locking the locking unit to the frame; the locking unit drives the pin shaft to move upward, so that the pin shaft is removed from the positioning hole on the support plate on the frame, thereby unlocking the locking unit from the fixed seat and the frame. The structure is simple, the operation is convenient, and the degree of automation is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described in further detail below with reference to the accompanying drawings.

[0018] Figure 1 This is the structural front view of the distance adjustment device between the jaws of the skin stretching machine; Figure 2 yes Figure 1 Structural cross-section view at AA in the middle; Figure 3 This is the actual effect diagram of the distance adjustment device between the jaws of the skin stretching machine (the top view is rotated 90° to the right).

[0019] Explanation of reference numerals: 1. moving cylinder; 2. fixing seat; 3. flange; 4. moving seat; 5. frame; 6. locking mechanism; 7. guide rail; 8. stretching machine jaw; 9. bracket; 2.51, hole; 5.1. Upper support plate; 5.2. Support body; 5.11, positioning hole; 6.1. Locking cylinder; 6.2. Articulated seat; 6.3. Pin. DETAILED DESCRIPTION

[0020] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0021] Example 1: like Figure 1 and Figure 2 As shown, a device for adjusting the distance between the jaws of a skin stretching machine includes four adjusting units, which are symmetrically arranged front to back and left to right. The adjusting units include a movable cylinder 1, a fixed seat 2, a movable seat 4, a frame 5 and a locking mechanism 6. In the adjusting unit on the left, the upper side of the frame 5 is connected to the fixed seat 2 and the movable seat 4 from left to right in sequence, the movable cylinder 1 is connected to the fixed seat 2 on the right, and the power output end of the movable cylinder 1 passes through the fixed seat 2 and is connected to the left end of the movable seat 4, and the fixed seat 2 is connected to the frame 5 through the locking mechanism 6.

[0022] Specifically, the fixed seat 2 and the movable seat 4 are both slidably connected to the frame 5. The distance between the stretching machine jaws 8 between the two groups of adjustment units can be adjusted through the cooperation of the movable cylinder 1, the fixed seat 2, the movable seat 4, the frame 5 and the locking mechanism 6. It can adapt to the production of skin parts of different sizes and has the advantages of convenient adjustment, stability and reliability. The target distance between the stretching machine jaws 8 between the two groups of adjustment units is adjusted by gradually reducing the distance through the cooperation of the movable cylinder 1, the fixed seat 2, the movable seat 4, the frame 5 and the locking mechanism 6. Compared with relying entirely on the stroke of the movable cylinder to adjust the distance between the stretching machine jaws, the stroke of the movable cylinder 1 of the present invention is only less than 1 / 3 of the stroke of the stretching machine movable cylinder that relies entirely on the stroke of the movable cylinder to adjust the distance between the stretching machine jaws, avoiding all problems existing in the excessive stroke of the movable cylinder, and having the characteristics of high work efficiency, long service life and easy maintenance.

[0023] Example 2: On the basis of Example 1, a guide rail 7 is provided on the upper surface of the frame 5 , and the fixed seat 2 and the movable seat 4 are both installed on the guide rail 7 .

[0024] Specifically, the fixed seat 2 and the movable seat 4 are both slidably connected to the guide rail 7, which has a simple structure and facilitates the sliding of the fixed seat 2 and the movable seat 4 as needed, and saves effort in movement.

[0025] Preferably, the movable cylinder 1 is a movable cylinder having a piston rod, and the piston rod of the movable cylinder 1 passes through the fixed seat 2 and is connected to the left end of the movable seat 4.

[0026] Specifically, the power output end adopts a piston rod, which has a simple structure and can push the moving seat 4 a certain distance, and the connection is stable.

[0027] Preferably, the piston rod of the movable cylinder 1 is connected to the movable seat 4 via a flange 3. The flange 3 is used for connection, which is convenient for installation and removal.

[0028] Example 3: Based on Example 2, the locking mechanism 6 includes two sets of locking units and a pin shaft 6.3. The two sets of locking units are connected in the fixing seat 2, and the two sets of locking units are symmetrically arranged front to back. The pin shaft 6.3 is connected between the power output ends of the two sets of locking units.

[0029] Specifically, the locking mechanism 6 includes two sets of locking units and a pin 6.3. The two sets of locking units are symmetrically arranged on both sides of the movable cylinder 1. The pin 6.3 is connected between the power output ends of the two sets of locking units. The two sets of locking units facilitate the control of the up and down movement of the pin 6.3, resulting in a simple structure and easy operation.

[0030] Preferably, the locking unit includes a locking cylinder 6.1 and an articulated seat 6.2, the fixed seat 2 is connected to the locking cylinder 6.1 through the articulated seat 6.2, and the upper ends of the pin shaft 6.3 are connected between the power output ends of the two locking cylinders 6.1.

[0031] Specifically, the power output end of the locking cylinder 6.1 is convenient for controlling the pin shaft 6.3 to move up and down, and the locking cylinder 6.1 is convenient for being stably connected to the fixing base 2 through the hinge seat 6.2 to ensure the stability of the structure during movement.

[0032] Preferably, the locking cylinder 6.1 is a locking cylinder with a piston rod, and the piston rods of the two locking cylinders 6.1 are connected to the upper ends of the pin shaft 6.3.

[0033] Specifically, the power output end of the locking cylinder 6.1 is a piston rod, which is hingedly connected to the pin 6.3. The piston rod has a simple structure, which is conducive to moving the pin 6.3 up and down a target distance. The hinged connection reduces stress concentration and is easy to install and disassemble.

[0034] Embodiment 4: On the basis of embodiment 3, the frame 5 includes an upper support plate 5.1 and a support body 5.2. The upper surface of the support body 5.2 is connected to the upper support plate 5.1, and the upper surface of the upper support plate 5.1 is connected to the guide rail 7.

[0035] Specifically, the frame 5 of this structure has a simple structure and good stability.

[0036] Preferably, a plurality of positioning holes 5.11 are formed on the upper support plate 5.1, and the plurality of positioning holes 5.11 are located at the guide rail and spaced apart along the guide rail direction.

[0037] Specifically, by inserting the pin 6.3 into the positioning hole 5.11, the fixing base 2 is locked to the frame 5. By removing the pin 6.3 from the positioning hole 5.11, the fixing base 2 is unlocked from the frame 5. This simple structure facilitates locking and unlocking. Multiple positioning holes 5.11 are spaced along the guide rail to accommodate adjustments at different distances.

[0038] Preferably, the number of the positioning holes 5.11 is 3. The 3 positioning holes 5.11 can satisfy the adjustment of three distances: large, medium and small.

[0039] Preferably, the distance between two adjacent positioning holes 5.11 among the plurality of positioning holes 5.11 is equal to the stroke of the moving cylinder 1.

[0040] Specifically, this arrangement ensures that the fixing seat 2 can be locked after the movable cylinder 1 is fully extended or retracted.

[0041] Preferably, a hole 2.51 is provided on the bottom of the fixing seat 2.

[0042] Specifically, the hole 2.51 serves to limit the position of the pin 6.3.

[0043] Preferably, the hole 2.51 and the positioning hole 5.11 have the same diameter.

[0044] Specifically, the same hole diameter ensures that after the pin shaft 6.3 passes through the positioning hole 5.11, the fixing seat 2 will not move on the guide rail, thereby ensuring the stability of the fixing seat after locking.

[0045] Example 5: On the basis of Example 4, Figure 3 As shown, a method for adjusting the distance between the jaws of a skin stretching machine includes the following steps: S1. The four adjustment units are symmetrically arranged front and back and left and right. The four adjustment units are divided into two groups, the movable base 4 of each group of adjustment units is connected to the stretching machine jaws 8 via a bracket 9. In the initial state of the skin stretching machine, the locking mechanism 6 is locked on the fixed base 2 and the frame 5. At this time, the distance between the stretching machine jaws 8 between the two groups of adjustment units is at its maximum. S2. When it is necessary to reduce the distance between the jaws 8 of the stretching machine between the two groups of adjustment units, the power output end of the mobile cylinder 1 extends to push the movable seat 4 to move toward the middle until the power output end of the mobile cylinder 1 is fully extended and stops, the pin 6.3 is pulled out from the positioning hole 5.11 on the frame 5, and the locking mechanism 6 is unlocked from the frame 5. Then the power output end of the mobile cylinder 1 retracts, and the fixed seat 2 moves toward the middle under the push of the power output end of the mobile cylinder 1 until the power output end of the mobile cylinder 1 is fully retracted and stops, the pin 6.3 is inserted into the positioning hole 5.11 on the frame 5, and the locking mechanism 6 is locked on the frame 5 again, completing the reduction of the target distance between the jaws 8 of the stretching machine; S3. When it is necessary to further reduce the distance between the stretching machine jaws 8 between the two groups of adjustment units, repeat the above step S2 until the distance between the stretching machine jaws 8 between the two groups of adjustment units is reduced to the target position, completing the reduction adjustment of the target distance between the stretching machine jaws 8 between the two groups of adjustment units.

[0046] Compared with the method of adjusting the distance between the jaws of the stretching machine entirely by the stroke of the moving cylinder, the stroke of the moving cylinder 1 of the present invention is only less than 1 / 3 of the stroke of the moving cylinder of the stretching machine, which avoids all problems caused by excessive stroke of the moving cylinder and has the characteristics of high work efficiency, long service life and easy maintenance.

[0047] Example 6: Based on Example 5, a method for adjusting the distance between the jaws of a skin stretching machine includes the following steps: S1. The four adjustment units are symmetrically arranged front to back and left to right, and the four adjustment units are divided into two groups on the left and right. The movable seats 4 of each group of adjustment units are connected to the jaws 8 of the stretching machine through the bracket 9; in the initial state of the skin stretching machine, the piston rods of the two locking cylinders 6.1 extend downward, driving the pin 6.3 to move downward, so that the pin 6.3 passes through the positioning hole 5.11, and the locking mechanism 6 is locked on the frame 5. At this time, the distance between the jaws 8 of the stretching machine between the two groups of adjustment units is the maximum; the longitudinal skin stretching machine can form skin parts with the largest size allowed by the stretching machine.

[0048] S2. If you want to form a skin part of intermediate size, when you need to reduce the distance between the stretching machine jaws 8 between the two sets of adjustment units, the piston rod of the moving cylinder 1 extends to push the moving seat 4 to the middle (between the two sets of adjustment units) until the piston rod of the moving cylinder 1 is fully extended, and the piston rods of the two locking cylinders 6.1 retract upward, driving the pin 6.3 to move upward, so that the pin 6.3 moves out of the positioning hole 5.11, and the locking mechanism 6 is unlocked from the frame 5; the piston rod of the moving cylinder 1 retracts, (because the stretching machine jaws 8 and bracket 9 weigh more than 70 tons, and the solid The fixed seat 2 weighs only about 15 tons. At this time, the fixed seat 2 will move along the guide rail 7 toward the moving seat 4 under the push of the piston of the mobile cylinder 1 until the piston rod of the mobile cylinder 1 is fully retracted), driving the fixed seat 2 to move toward the middle until the piston rod of the mobile cylinder 1 is fully retracted and stops. The piston rods of the two locking cylinders 6.1 extend downward, driving the pin 6.3 to move downward, so that the pin 6.3 passes through the positioning hole 5.11, and the locking mechanism 6 is locked on the frame 5. At this position, the distance between the jaws 10 of the stretching machine is in the middle position, and the stretching machine can form skin parts of allowable intermediate sizes.

[0049] S3. If you want to form a small skin part and need to further reduce the distance between the jaws 8 of the stretcher between the two sets of adjustment units, repeat the above step S2 to adjust the position of the moving cylinder 1 of each adjustment unit, and finally make the locking cylinder 6.1 drive the pin 6.3 to insert into the positioning hole 5.11. At this position, the distance between the jaws 8 of the stretcher can be minimized, and the stretcher can form the skin part of the minimum size allowed.

[0050] The stroke of the movable cylinder of the present invention is only 1 / 3 of the stroke of the movable cylinder of the stretching machine which entirely relies on the movable cylinder stroke to adjust the distance between the jaws of the stretching machine, thereby avoiding all problems existing in the case of excessive movable cylinder stroke, and having the characteristics of high working efficiency, long service life and convenient maintenance.

[0051] In the description of the present invention, it should be understood that if there are terms such as "left", "inside", and "right" indicating directions or positional relationships, these directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationships in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention.

[0052] The above examples are merely illustrative of the present invention and do not limit the scope of protection of the present invention. Any design that is identical or similar to the present invention falls within the scope of protection of the present invention.

Claims

1. A device for adjusting the distance between jaws of a skin stretching machine, characterized in that: The invention comprises four adjustment units, which are symmetrically arranged front to back and left to right. The adjustment units comprise a movable cylinder (1), a fixed seat (2), a movable seat (4), a frame (5) and a locking mechanism (6). In the left adjustment unit, the upper side of the frame (5) is connected to the fixed seat (2) and the movable seat (4) in sequence from left to right. The right side of the movable cylinder (1) is connected to the fixed seat (2), and the power output end of the movable cylinder (1) passes through the fixed seat (2) and is connected to the left end of the movable seat (4). The fixed seat (2) is connected to the frame (5) via the locking mechanism (6).

2. The device for adjusting the distance between jaws of a skin stretching machine according to claim 1, characterized in that: A guide rail (7) is arranged on the upper side of the frame (5) and connected thereto, and the fixed seat (2) and the movable seat (4) are both mounted on the guide rail (7).

3. The device for adjusting the distance between jaws of a skin stretching machine according to claim 2, characterized in that: The locking mechanism (6) comprises two sets of locking units and a pin shaft (6.3); the two sets of locking units are connected inside the fixing seat (2), and the two sets of locking units are symmetrically arranged front to back; the pin shaft (6.3) is connected between the power output ends of the two sets of locking units.

4. The device for adjusting the distance between jaws of a skin stretching machine according to claim 3, characterized in that: The locking unit comprises a locking cylinder (6.1) and an articulated seat (6.2); the fixed seat (2) is connected to the locking cylinder (6.1) via the articulated seat (6.2); and the upper ends of the pin shafts (6.3) are connected between the power output ends of the two locking cylinders (6.1).

5. The device for adjusting the distance between jaws of a skin stretching machine according to claim 4, characterized in that: The frame (5) comprises an upper support plate (5.1) and a support body (5.2); the upper side of the support body (5.2) is connected to the upper support plate (5.1); and the upper side of the upper support plate (5.1) is connected to the guide rail (7).

6. The device for adjusting the distance between jaws of a skin stretching machine according to claim 5, characterized in that: The upper support plate (5.1) is provided with a plurality of positioning holes (5.11), and the plurality of positioning holes (5.11) are located on the guide rail and are arranged at intervals along the direction of the guide rail.

7. The device for adjusting the distance between jaws of a skin stretching machine according to claim 6, characterized in that: The distance between two adjacent positioning holes (5.11) among the plurality of positioning holes (5.11) is equal to the stroke of the moving cylinder (1).

8. The device for adjusting the distance between jaws of a skin stretching machine according to claim 7, characterized in that: A hole (2.51) is provided on the bottom of the fixing seat (2).

9. The device for adjusting the distance between jaws of a skin stretching machine according to claim 8, characterized in that: The movable cylinder (1) is a movable cylinder having a piston rod, the piston rod of the movable cylinder (1) passes through the fixed seat (2) and is connected to the left end of the movable seat (4); the locking cylinder (6.1) is a locking cylinder having a piston rod, the piston rods of the two locking cylinders (6.1) are connected to the upper ends of the pin shafts (6.3).

10. A method for adjusting the distance between jaws of a skin stretching machine, characterized in that: The steps include: S1. The four adjustment units are symmetrically arranged front to back and left to right, and the four adjustment units are divided into two groups, the movable seats (4) of each group of adjustment units are connected to the jaws (8) of the stretching machine via brackets (9); in the initial state of the skin stretching machine, the locking mechanism (6) is locked on the frame (5), and at this time, the distance between the jaws (8) of the stretching machine between the two groups of adjustment units is the maximum; S2. When it is necessary to reduce the distance between the jaws (8) of the stretching machine between the two groups of adjustment units, the power output end of the mobile cylinder (1) extends to push the mobile seat (4) to move toward the middle until the power output end of the mobile cylinder (1) is fully extended and stops, the pin shaft (6.3) is pulled out from the positioning hole (5.11) on the frame (5), and the locking mechanism (6) is unlocked from the frame (5). Then, the power output end of the mobile cylinder (1) contracts, and the fixed seat (2) moves toward the middle under the push of the power output end of the mobile cylinder (1) until the power output end of the mobile cylinder (1) is fully retracted and stops, the pin shaft (6.3) is inserted into the positioning hole (5.11) on the frame (5), and the locking mechanism (6) is locked on the frame (5) again, completing the reduction of the target distance between the jaws (8) of the stretching machine; S3. When it is necessary to further reduce the distance between the jaws (8) of the stretching machine between the two groups of adjustment units, the above step S2 is repeated until the distance between the jaws (8) of the stretching machine between the two groups of adjustment units is reduced to the target position, thereby completing the reduction adjustment of the target distance between the jaws (8) of the stretching machine between the two groups of adjustment units.

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