CN107242900A - Orthopaedics internal fixation screw extractor - Google Patents

Abstract

The invention relates to a remover for orthopedic internal fixation screws. In order to solve the problem of difficult removal of orthopedic internal fixation screws, it is an outer hexagonal or hexagonal star wrench column made of tool steel made of tool steel with the same thickness at the top and bottom or thickened at the bottom and left and right. body, the upper buckle is equipped with an upper end cap or is hinged to each other; the lower part of the right lobe of the outer hexagonal or hexagonal star wrench cylinder is fixed with a side extension handle for rotation and force, and the clockwise rear of the lower end of the right lobe wrench wrench The inner end face is equipped with a spring for outwardly extruding the left lobe of the lower end of the outer hexagonal or hexagonal star wrench cylinder relative to the inner end face. The outer hexagonal or hexagonal star wrench cylinder lower end outer periphery that left and right two petals are formed has anticlockwise obliquely extending protruding teeth. The utility model has the advantages of being able to significantly enhance the occlusal force, easy to use, good anti-slip performance, low cost, no metal debris, no heat generation, strong safety, not easy to produce slippery buckles, and especially suitable for the removal of slippery buckle screws.

Description

Orthopedic Internal Fixation Screw Extractor

technical field

The invention relates to an orthopedic internal fixation screw extractor, in particular to an orthopedic internal fixation screw extractor.

Background technique

It is very common to fix fractures with plates and screws in trauma orthopedics. Most of the plates and screws need to be taken out after the fracture heals. During the process of taking out, the screws often slip and buckle, especially in recent years when titanium alloy plates and titanium alloy screws appear. It is more common and is a very difficult problem for orthopedic surgeons. In the case of screw slippage, the current common method is to use a tungsten steel drill to deepen the end cap of the screw, use a tapered reverse thread drill, connect it to the T handle or an electric drill, squeeze the screw longitudinally with force, and rotate it in the opposite direction, so that The tapered anti-thread drill and the screw are "locked". Sometimes the screw can be successfully removed, but sometimes the "lock" cannot occur, and sometimes the anti-thread drill suddenly breaks after the sudden "lock". Another is to use a steel saw to cut off the steel plate to expose the screw end cap, and then try to unscrew the screw, but using a steel saw will generate a lot of metal debris, high temperature, easy to cause soft tissue damage, and even refracture.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned defects of the prior art, and to provide an orthopedic internal fixation screw extractor that is easy to use and has good anti-slip performance.

In order to achieve the above object, the orthopedic internal fixation screw extractor of the present invention is an outer hexagonal or hexagonal star wrench cylinder made of tool steel made of tool steel with the same thickness up and down or thickened above the lower end. The upper end is equipped with an upper end cap or Hinged to each other; the lower part of the right lobe of the outer hexagonal or hexagonal star wrench cylinder is fixed with a side extension handle for rotation and force, and the clockwise rear inner end of the lower end of the right lobe wrench cylinder is equipped with a handle for outward extrusion. The spring of the left lobe of the lower end of the outer hexagonal or hexagonal star wrench cylinder relative to the inner end face. Described spring comprises all springs such as helical spring, shrapnel type spring, elastic wire type spring. When in use, when one hand presses down on the upper end cap and the other hand rotates the side extension handle counterclockwise, the inner side of the front end of the right flap (counterclockwise) will squeeze the inner side of the rear end of the left flap (counterclockwise), plus The opening force of the inner side of the rear end of the right lobe (counterclockwise) and the inner side of the front end of the left lobe (counterclockwise) supported by the spring makes the outer hexagon or the lower end of the hexagonal star wrench composed of the left and right lobe can grasp the screw end cap firmly. The inner hexagonal or hexagonal star notch, which can significantly reduce the difficulty of taking out the screw; before inserting the lower end of the outer hexagonal or hexagonal star wrench composed of two petals into the inner hexagonal or hexagonal star notch on the screw end cap, it should be Use pliers or other fixtures to clamp the lower part of the outer hexagonal or hexagonal star wrench cylinder composed of the left and right halves, insert it into the inner hexagonal or hexagonal star notch on the screw end cap, and press down on the upper end cap at the same time , loosen the pliers or other fixtures, let the spring spread the outer hexagon or the lower end of the hexagonal star wrench composed of the left and right petals, so that the outer circumference of the lower end of the wrench tightly touches the inner hexagonal or hexagonal star groove on the screw end cap mouth. The thickening above the bottom end can be thickened in one step, or the first paragraph can be thickened upwards first, and the rest of the paragraphs can be further thickened on the basis of the previous thickened first paragraph. Of course, the length of the first thickened paragraph is several times longer than The length of the lower end is sufficient, and the rest of the thickened section is used as the main section of the wrench body. The utility model has the advantages of being easy to use and having good anti-slip performance.

As an optimization, the outer periphery of the outer hexagon or hexagonal star wrench cylinder lower end formed by the left and right lobes is provided with protruding teeth extending obliquely in the counterclockwise direction. The introduction of obliquely extending convex teeth in the counterclockwise direction on the outer periphery can significantly enhance the bite force, and is more simple and easy to use, with good anti-slip performance, low cost, no metal debris, no heat generation, strong safety, and is not easy to produce slippery buttons and Especially suitable for the advantages of slide buckle screw removal.

As an optimization, the obliquely protruding protruding tooth in the counterclockwise direction is the vertical edge protruding vertically outward from the outer edge surface of the lower end of the wrench cylinder or the hexagonal star edge surface and the outer edge surface clockwise from the vertical edge end. Or the obliquely stretched convex teeth in the counterclockwise direction surrounded by the oblique straight sides of the six-pointed star side. In this way, the anticlockwise oblique support force of the protruding teeth is strong.

As an optimization, the upper end buckle of the wrench cylinder is equipped with a handle-type upper end cap for downward force. Elastic touch beads and matching annular grooves or pits are prepared between the inner circumference of the upper end cap; or the upper end of the wrench cylinder is in the shape of a handle with downward force and passes through a horizontal shaft or a universal shaft or a ball head. The bowl is hinged. The upper end of the handle-type upper end cap and the wrench cylinder are in the shape of a handle with downward force and are hinged by a horizontal axis, so that their upper ends are in a flat-convex shape that is convenient for downward pressure and force, and there is enough area for sharing the pressure. When the annular groove adopts the annular groove, at least the upper end of the wrench cylinder and the inner chamber of the matching upper end cap have a circular cross-section.

As an optimization, the left and right flaps of the wrench cylinder are thickened above the lower end or only the lower end of the right flap of the fixed side extension handle is thickened, and the side extension handle is fixed at the bottom of the thickened right flap. When the left and right two lobe lower ends of the wrench cylinder are all thickened, the thickening becomes a circle.

As an optimization, the side extension handle is a horizontal extension handle or an upward oblique extension handle, and the base of the side extension handle is horizontally extended and connected to the lower part of the right flap, or the base of the side extension handle is obliquely connected to the lower part of the right flap. The upper bevel angle of the upper oblique handle is about 30 or 45 degrees.

As an optimization, the lower ends of the left and right petals of the wrench cylinder are symmetrical two petals that are evenly divided on the left and right. The small part is the left lobe. About 2/3 of the area of the thickened part is the right lobe with handle, and about 1/3 of the area of the thickened part is the left lobe.

As an optimization, at least the lower end of the left and right lobes of the wrench cylinder is a symmetrical two lobes that are evenly divided on the left and right, and its equal line is located on the diagonal or on the center line of the opposite side; the spring is formed from the lower end of the wrench cylinder. The rear inner end surface of the right lobe in the clockwise direction is a helical support spring or a shrapnel spring or an elastic wire spring that is laterally ejected from the pit.

As an optimization, the right lobe above the lower end is thickened; or the parts above the lower ends of the left and right petals are thickened simultaneously, or the parts above the lower ends of the left and right petals are thickened differently, and most of the thickened part is the right lobe with handle, thickened The small part of the part is the left lobe; the clockwise rear inner end surface of the lower end of the right lobe wrench cylinder is shaped with a lateral pit, and the spring is a helical support. The side of the pit is ejected outward; or the spring is a shrapnel-type spring whose base is embedded in the lateral pit, and the outer end is ejected outward from the pit side.

As an optimization, the lower end of the wrench cylinder is equipped with a lower end cap, and the lower part of the two-piece wrench cylinder is equipped with a clamp. The clamp is a movable pressure rod hinged at the base of the side extension handle through a horizontal axis. When the movable pressure rod is lifted up, the two petals are released, and when the movable pressure rod is pulled to the level from top to bottom, the two petals are squeezed and closed.

The main part of the device is composed of two half hexagonal or hexagonal star cylinders (the two parts form a complete regular hexagonal or hexagonal star cylinder, the lower end of which is connected to the notch or blind hole of the inner hexagonal or inner hexagonal star tail cap of the screw. They coincide. There are longitudinal grooves or protruding teeth extending counterclockwise on the sides of the lower ends of the two petals. The grooves or protruding teeth protruding counterclockwise form a right triangle. The sides face in the counterclockwise direction, which can increase the friction between them and the inner wall of the slide button screw cap. There is an elastic steel wire or spring between the two half hexagonal or hexagonal star cylinders. The elastic steel wire or spring makes the main part two The lower end of the petal is separated, which can increase the pressure of the notch between the hexagonal or hexagonal star cylinder and the end cap. When the two petals are placed in the screw end cap at the same time, the elastic steel wire or spring will open. The auxiliary part is connected by a half The side extension handle of the hexagonal or hexagonal star cylinder and the upper end cap fastening or fastening the upper ends of the two half hexagonal or hexagonal star cylinders.

When in use, the lower part of the body is clamped, and the lower end is placed in the screw tail cap of the slide buckle. The elastic steel wire or spring separates the two half-hexagonal or hexagonal star wrench cylinders from each other, and the hexagonal or hexagonal star wrench cylinder and tail are added. Initial pressure between the inner walls of the cap, grasp the upper end cap with one hand, grasp the side extension handle with the other hand, and rotate the main part counterclockwise to keep the main part of the wrench upright. At this time, the pressure between the lower end of the two half-hexagonal or hexagonal star wrench cylinders and the inner wall of the tail cap will increase, so the friction will also increase. The greater the force of counterclockwise rotation, the greater the resulting friction. Eventually the screws of the slider will be unscrewed.

After adopting the above technical solution, the orthopedic internal fixation screw extractor of the present invention can significantly enhance the occlusal force, is simple and easy to use, has good anti-slip performance, low cost, does not produce metal debris, does not generate heat, has strong safety, and is not easy to produce slippage. Advantages of buckle and screw removal especially suitable for slide buckle.

Description of drawings

Fig. 1 is a front structural schematic diagram of the first embodiment of the orthopedic internal fixation screw extractor of the present invention; Fig. 2 is a right view structural schematic diagram of the first embodiment of the orthopedic internal fixation screw extractor of the present invention; Fig. 3 is a schematic diagram of Fig. 2 A-A direction view; Fig. 4-5 are respectively the schematic diagrams of the lower part of the second and third implementations of the orthopedic internal fixation screw extractor of the present invention; Fig. 6-9 are the fourth and fifth orthopedic internal fixation screw extractors of the present invention respectively 1. Schematic structural diagrams of the bottom right view of six or seven implementations.

detailed description

Embodiment 1, as shown in Figures 1-3, the orthopedic internal fixation screw extractor of the present invention is a lower outer hexagonal (or hexagonal) composed of left and right petals made of tool steel with the same thickness (or thicker above the lower end). star), the upper cylindrical wrench cylinder, the upper end buckle is equipped with an upper end cap 3 (or hinged to each other); the lower part of the right wrench cylinder 1 of the outer hexagonal (or hexagonal star) wrench cylinder is fixed for rotation. Side extension handle 4, the rear inner end face of the clockwise direction of the right lobe wrench cylinder 1 lower end is equipped with the spring 5 for extruding the relative inner end surface of the left lobe wrench cylinder 2 lower end outwards. Described spring comprises all springs such as helical spring, shrapnel type spring, elastic wire type spring.

Specifically: the left and right petals of the wrench cylinder are symmetrical two petals that are evenly divided on the left and right, and the equidistribution line is located on the diagonal (or on the center line of the opposite side); the spring 5 is formed from the lower end of the wrench cylinder. The shrapnel type spring 5 (or helical support spring or elastic wire type spring) that is ejected laterally from the rear inner end surface of the right lobe of the portion in the clockwise direction toward the pit side. The rear inner end surface of the clockwise direction of the lower end of the right flap wrench cylinder 1 is shaped with a lateral pit 10, and the spring 5 is a shrapnel spring (or spring wire spring) whose base is embedded in the lateral pit, and the outer end is inserted into the lateral pit. The pit 10 pops out from the side (or the spring is a helical support spring whose base is fixed on the bottom of the side pit, and the outer end pops out from the side of the pit).

Specifically: the outer hexagonal or hexagonal star wrench cylinder lower end outer periphery that left and right two petals are formed has anticlockwise obliquely extending protruding tooth 7. The anticlockwise obliquely protruding protruding tooth 7 is a vertical edge that protrudes vertically outward from the outer edge surface (or hexagonal star edge surface) of the lower end of the wrench cylinder and leads clockwise from the vertical edge end to the outer edge surface. (or the hexagonal star side) the obliquely stretched protruding teeth 7 in the counterclockwise direction surrounded by the oblique straight sides. In this way, the anticlockwise oblique support force of the protruding teeth is strong. The introduction of the obliquely extending convex teeth 7 in the counterclockwise direction on the outer periphery can significantly enhance the bite force, and is more simple and easy to use, with good anti-slip performance, low cost, no metal debris, no heat generation, strong safety, and not easy to produce slip buttons And the advantage that it is especially suitable for the extraction of slide buckle screws.

Specifically: the upper end buckle of the wrench cylinder is equipped with a handle-type upper end cap 3 for downward force, the upper end of the wrench cylinder is matched with the upper end cap 3, and there is a gap between the outer circumference of the upper end of the wrench cylinder and the inner circumference of the upper end cap 3. Elastic touch beads 31 and annular grooves 30 (or pits) matched therewith are prepared. When the annular groove adopts the annular groove, at least the upper end of the wrench cylinder and the inner chamber of the matching upper end cap have a circular cross-section. (It can also be a handle type with a downward force on the upper end of the wrench cylinder and is hinged by a horizontal shaft or a cardan shaft or a ball head). The handle-type upper end cap 3 (or the handle type at the upper end of the wrench cylinder and the handle type that is downwardly applied by being hinged through the horizontal axis) is that their upper ends are in a flat and convex shape that is convenient for pressing down and applying force, and There is enough area to share the pressure. The side extension handle 4 is a horizontal extension handle, and the base of the side extension handle 4 is horizontally extended and fixedly connected to the lower part of the right lobe (or the base of the side extension handle is obliquely connected to the lower part of the right lobe. The upper oblique angle of the upper oblique extension handle Preferably around 30 or 45 degrees).

Specifically: the lower end of the wrench cylinder is equipped with a lower end cap, and the lower part of the two-petal wrench cylinder is equipped with a clamp. The two-petal clamp is a movable pressure rod hinged at the base of the side extension handle 4 through a horizontal axis. When the movable pressure rod is lifted up, the two petals are released. Press to close.

When in use, when one hand presses down on the upper end cap or the upper end, and the other hand rotates the side extension handle counterclockwise, the inner surface of the front end of the right flap (counterclockwise) will squeeze the inner surface of the rear end of the left flap (counterclockwise), Coupled with the opening force of the inner side of the rear end of the right lobe (counterclockwise) and the inner side of the front end of the left lobe (counterclockwise) supported by the spring, the lower end of the outer hexagonal or hexagonal star wrench composed of the left and right lobe can grasp the screw tail. The inner hexagonal or hexagonal star notch on the cap, which can significantly reduce the difficulty of taking out the screw; insert the lower end of the outer hexagonal or hexagonal star wrench composed of two petals into the front of the inner hexagonal or hexagonal star notch on the screw end cap , use pliers or other fixtures to clamp the lower part of the outer hexagonal or hexagonal star wrench cylinder composed of the left and right halves, insert it into the inner hexagonal or hexagonal star notch on the screw end cap, and press down on the upper end cap firmly At the same time, loosen the pliers or other fixtures, let the spring spread the outer hexagon or the lower end of the hexagonal star wrench composed of the left and right flaps, so that the outer circumference of the lower end of the wrench tightly touches the inner hexagonal or hexagonal on the screw end cap. star notch. The thickening above the bottom end can be thickened in one step, or the first paragraph can be thickened upwards first, and the rest of the paragraphs can be further thickened on the basis of the previous thickened first paragraph. Of course, the length of the first thickened paragraph is several times longer than The length of the lower end is sufficient, and the rest of the thickened section is used as the main section of the wrench body. The utility model has the advantages of being easy to use and having good anti-slip performance.

Embodiment 2, as shown in Figure 4, the difference between the orthopedic internal fixation screw extractor of the present invention and Embodiment 1 is that the lower ends of the left and right two petals of the wrench cylinder are synchronously thickened into a circle, and the side extension handle 4 is fixed on the thickened lower part of the right lobe.

Embodiment 3, as shown in FIG. 5 , the difference between the orthopedic internal fixation screw extractor of the present invention and Embodiment 1 is that the wrench cylinder is only fixedly mounted on the lower end of the right flap of the side extension handle 4 and is thickened, and the side extension handle 4 is fixed on the Bold lower part of right lobe. It can also be: the lower ends of the left and right petals of the wrench cylinder are symmetrical two petals that are evenly divided on the left and right, the large part of the thickened part is the right petal with a handle, and a small part of the thickened part is the left petal. About 2/3 of the area of the thickened part is the right lobe with handle, and about 1/3 of the area of the thickened part is the left lobe.

Embodiment 4, as shown in Figure 6, the difference between the orthopedic internal fixation screw extractor of the present invention and Embodiment 1 is that the side extension handle 4 is an upward oblique handle, and the base of the side extension handle 4 is horizontally extended and fixedly connected to the lower part of the right valve . The upper bevel angle of the upper bevel handle is preferably about 30 or 45 degrees.

Embodiment 5, as shown in FIG. 7 , the difference between the orthopedic internal fixation screw extractor of the present invention and Embodiment 1 is that the extension handle 4 is an upward oblique extension handle, and the base of the side extension handle 4 is obliquely connected to the lower part of the right valve. The upper bevel angle of the upper bevel handle is preferably about 30 or 45 degrees.

Embodiment 6, as shown in Figure 8, the difference between the orthopedic internal fixation screw extractor of the present invention and Embodiment 4 is that the lower ends of the left and right flaps of the wrench cylinder are thickened synchronously or only the lower end of the right flap of the side extension handle is fixed. Thick, side extension handle 4 is fixed on the right lobe bottom of thickening.

Embodiment 7, as shown in Figure 9, the difference between the orthopedic internal fixation screw extractor of the present invention and Embodiment 5 is that the lower ends of the left and right two petals of the wrench cylinder are thickened synchronously or only the lower end of the right petal of the side extension handle is fixed. Thick, side extension handle 4 is fixed on the right lobe bottom of thickening.

The main part of the device is composed of two half hexagonal or hexagonal star cylinders (the two parts form a complete regular hexagonal or hexagonal star cylinder, the lower end of which is connected to the notch or blind hole of the inner hexagonal or inner hexagonal star tail cap of the screw. They coincide. There are longitudinal grooves or protruding teeth extending counterclockwise on the sides of the lower ends of the two petals. The grooves or protruding teeth protruding counterclockwise form a right triangle. The sides face in the counterclockwise direction, which can increase the friction between them and the inner wall of the slide button screw cap. There is an elastic steel wire or spring between the two half hexagonal or hexagonal star cylinders. The elastic steel wire or spring makes the main part two The lower end of the petal is separated, which can increase the pressure of the notch between the hexagonal or hexagonal star cylinder and the end cap. When the two petals are placed in the screw end cap at the same time, the elastic steel wire or spring will open. The auxiliary part is connected by a half The side extension handle of the hexagonal or hexagonal star cylinder and the upper end cap fastening or fastening the upper ends of the two half hexagonal or hexagonal star cylinders.

When in use, the lower part of the body is clamped, and the lower end is placed in the screw tail cap of the slide buckle. The elastic steel wire or spring separates the two half-hexagonal or hexagonal star wrench cylinders from each other, and the hexagonal or hexagonal star wrench cylinder and tail are added. Initial pressure between the inner walls of the cap, grasp the upper end cap with one hand, grasp the side extension handle with the other hand, and rotate the main part counterclockwise to keep the main part of the wrench upright. At this time, the pressure between the lower end of the two half-hexagonal or hexagonal star wrench cylinders and the inner wall of the tail cap will increase, so the friction will also increase. The greater the force of counterclockwise rotation, the greater the resulting friction. Eventually the screws of the slider will be unscrewed.

After adopting the above technical solution, the orthopedic internal fixation screw extractor of the present invention can significantly enhance the occlusal force, is simple and easy to use, has good anti-slip performance, low cost, does not produce metal debris, does not generate heat, has strong safety, and is not easy to produce slippage. Advantages of buckle and screw removal especially suitable for slide buckle.

Claims (10)

1. An orthopedic internal fixation screw extractor is characterized in that the outer hexagonal or hexagonal star wrench cylinder made of tool steel is made of tool steel with the same thickness up and down or the left and right two petals thickened above the lower end, and the upper end buckle is equipped with an upper end cap or Hinged to each other; the lower part of the right lobe of the outer hexagonal or hexagonal star wrench cylinder is fixed with a side extension handle for rotation and force, and the clockwise rear inner end of the lower end of the right lobe wrench cylinder is equipped with a handle for outward extrusion. The spring of the left lobe of the lower end of the outer hexagonal or hexagonal star wrench cylinder relative to the inner end face. 2. The screw remover according to claim 1, characterized in that the outer hexagon or the lower end of the hexagonal star wrench cylinder composed of left and right lobes are provided with protruding teeth obliquely extending counterclockwise. 3. The screw extractor according to claim 2, wherein the protruding tooth obliquely protruding in the counterclockwise direction is a vertical edge extending vertically outward from the outer edge surface of the lower end of the wrench cylinder or the edge surface of the hexagonal star and extending from the vertical edge. The edge end leads clockwise to the obliquely stretched protruding teeth in the counterclockwise direction surrounded by the oblique straight sides of the outer edge face or the hexagonal star face. 4. The screw extractor according to claim 1, characterized in that the upper end of the wrench cylinder is equipped with a handle-type upper end cap for downward force, and the upper end of the wrench cylinder is matched with the upper end cap or the upper end of the wrench cylinder is matched with the upper end. The gap between the caps is matched, and there is an elastic bumper ball and a matching annular groove or pit between the outer circumference of the upper end of the wrench cylinder and the inner circumference of the upper end cap; or the upper end of the wrench cylinder is a downward force handle type And it is hinged by a transverse shaft or a cardan shaft or a ball joint. 5. The screw remover according to claim 4, characterized in that the bottom ends of the left and right two petals of the wrench cylinder are thickened above or only the bottom of the right petal of the fixed side extension handle is thickened, and the side extension handle is fixed on the thickened side. lower part of the right lobe. 6. The screw extractor according to claim 5, characterized in that the side extension handle is a horizontal extension handle or an upward oblique extension handle, and the base of the side extension handle is horizontally extended and fixedly connected with the lower part of the right flap or the base of the side extension handle is upward oblique The shape is firmly connected with the lower part of the right valve. 7. According to the described screw extractor of claim 5, it is characterized in that the lower end of the left and right two petals of the wrench cylinder is a symmetrical two petals equally divided on the left and right, and the left and right two petals of the wrench cylinder are thickened above the lower end, and the thickened part is larger. The upper portion is the right lobe with a stalk, and the small part of the thickened part is the left lobe. 8. The screw extractor according to claim 1, characterized in that at least the lower end of the left and right lobes of the wrench cylinder is a symmetrical two lobes that are evenly divided on the left and right, and the even line is located on the diagonal or on the center line of the opposite side The spring is a helical support spring or a shrapnel spring or a spring wire spring that pops out from the rear inner end surface of the right lobe of the lower end of the wrench cylinder in a clockwise direction to the side of the pit. 9. The screw extractor according to claim 8, characterized in that the right lobe above the lower end is thickened; or the parts above the lower ends of the left and right petals are thickened synchronously or the parts above the lower ends of the left and right petals are thickened differently, and the thickened part Most of the handle is the right lobe, and the small part of the thickened part is the left lobe; the clockwise rear inner end surface of the lower end of the right lobe wrench cylinder is shaped with a lateral pit, and the spring is a helical support spring base. It is fixed on the bottom of the side pit, and the outer end pops out from the side of the pit; or the spring is a shrapnel spring or spring wire spring whose base is embedded in the side pit, and the outer end pops out from the side of the pit. 10. The screw remover according to any one of claims 1-9, characterized in that the lower end of the wrench cylinder is equipped with a lower end cap, and the lower part of the two-lobed wrench cylinder is equipped with a clamp.