Manual hydraulic double-tooth expansion shearing device

Abstract

A manual hydraulic double-tooth expansion shearing device comprises an oil cylinder, a piston cavity formed in the center of the left end face of the oil cylinder, a piston arranged in the piston cavity and matched with the piston cavity, a piston rod arranged in the center of the left end face of the piston, an expansion shearing clamp assembly connected to the left end of the piston rod, an oil tank arranged at the rear end of the oil cylinder, and an oil tank cover covering a port of the rear end of the oil tank and matched with the oil tank cover. An oil way switching groove is formed in the upper surface of the rear part of the oil cylinder; an oil way switching device matched with the oil way switching groove is arranged in the oil way switching groove; an ejection oil way communicated with the oil way switching groove is arranged on the cavity wall of the right side of the piston cavity. An annular oil inlet groove is formed in the inner wall of a left end opening of the piston cavity, and the piston is located on the right side of the oil inlet groove. According to the manual hydraulic double-tooth expansion shearing device, normal operation of shearing work and expansion work can still be guaranteed after the spring is removed, the size can be effectively reduced, and the expansion shearing device can be conveniently moved and used.

Description

Technical Field

[0001] The utility model relates to an expansion shear, in particular to a manual hydraulic double-tooth expansion shear. Background Art

[0002] The expansion shear is a hydraulic tool that integrates expansion and shearing functions. It mainly uses the pressure of hydraulic oil to enable workers to complete the expansion and shearing work more easily. When the hydraulic oil pushes the piston, the double clamps of the expansion shear will close and generate shearing force. When the piston returns, the double clamps of the expansion shear will open and generate expansion force. The piston of the traditional expansion shear uses the elasticity of the spring to return. Therefore, when the piston is pushed out, the pressure of the hydraulic oil will compress the spring. At this time, the elasticity of the spring generated by compression will counteract the pressure of the hydraulic oil, causing the hydraulic oil pressure that ultimately acts on the double clamps of the expansion shear to eliminate part of the elasticity of the spring, affecting the shearing force of the expansion shear, and relying on the elasticity of the spring to return the piston. The expansion force generated by the expansion of the double clamps of the expansion shear mainly relies on the elasticity of the spring, resulting in extremely limited expansion force, making it difficult to expand objects that are tightly closed. At the same time, in order to be able to place the spring in the cylinder, it is necessary to increase the volume inside the cylinder, thereby increasing the volume of the cylinder, which ultimately affects the overall volume of the expansion shear, causing the expansion shear to become bulky and inconvenient to move and use. Summary of the invention

[0003] The utility model aims to solve the existing technical problem and provide a manual hydraulic double-tooth expansion shear, which can ensure the normal shearing and expansion work after the spring is removed, and can effectively reduce the volume, making it easier to move and use the expansion shear.

[0004] The technical solution adopted by the utility model to solve the above technical problems is:

[0005] The utility model discloses a manual hydraulic double-tooth expansion shearing tool, comprising an oil cylinder, a piston cavity arranged at the center of the left end face of the oil cylinder, a piston matching therewith is arranged in the piston cavity, a piston rod is arranged at the center of the left end face of the piston, the left end of the piston rod is connected with the expansion shearing pliers assembly, an oil tank is arranged at the rear end of the oil cylinder, and the rear end port cover of the oil tank is covered with an oil tank cover matching therewith, an oil circuit switching groove is arranged on the upper surface of the rear end of the oil cylinder; an oil circuit switching device matching therewith is arranged in the oil circuit switching groove; an ejection oil circuit which is communicated with the oil circuit switching groove is arranged on the right side cavity wall of the piston cavity; an annular oil inlet groove is arranged on the inner wall of the left end port of the piston cavity, and the piston is located on the right side of the oil inlet groove; a return oil circuit which is communicated with the oil circuit switching groove is arranged on the right side groove wall of the oil inlet groove; an oil delivery device located in the oil tank is arranged on the front side of the right end face of the oil cylinder; the oil delivery device comprises an oil pressing head, the right end of the oil pressing head passes through the oil tank cover to the right and is provided with a movable handle.

[0006] The oil delivery device includes an oil delivery seat arranged on the front side of the right end face of the oil cylinder; a sealing hole corresponding to the position of the oil delivery seat is arranged on the oil tank cover, and the right end of the oil delivery seat is embedded in the sealing hole; an oil pressure groove matching the oil pressure head is arranged at the center of the right end face of the oil delivery seat; a first low-pressure oil circuit connected to the bottom of the oil pressure groove is arranged at the lower side of the left end face of the oil delivery seat; an embedding hole is arranged at the center of the bottom of the oil pressure groove; a central oil pipe matching the same is arranged in the embedding hole; an auxiliary oil groove is arranged at the center of the left end face of the oil pressure head, The right end of the center oil pipe penetrates into the auxiliary oil groove; there is an oil inlet gap between the left end face of the center oil pipe and the bottom of the embedded hole; an upper oil suction hole is provided on the rear side wall of the oil delivery seat and is connected to the oil inlet gap; a first high-pressure oil circuit is provided on the upper side of the left end face of the oil delivery seat and is connected to the upper oil suction hole; a lower oil suction hole is provided on the rear side wall of the oil delivery seat and is connected to the first low-pressure oil circuit; a first connecting oil circuit is provided on the upper surface of the oil delivery seat; the first high-pressure oil circuit and the first low-pressure oil circuit are connected through the first connecting oil circuit.

[0007] The oil circuit switching device comprises a left switching hole arranged at the left center of the bottom of the oil circuit switching groove, a front switching hole arranged at the front side of the middle of the bottom of the oil circuit switching groove, a rear switching hole arranged at the rear side of the middle of the bottom of the oil circuit switching groove, and a right switching hole arranged at the right center of the bottom of the oil circuit switching groove; a limit groove is arranged on the inner wall of the notch on the upper side of the oil circuit switching groove; a limit block matching with it is arranged in the limit groove; a rotating hole is arranged at the center of the limit block; a switching rod matching with it is arranged in the rotating hole; the lower end of the switching rod passes downward to the rotating hole and A switching head matching the oil circuit switching groove is provided; the upper end of the switching rod passes upward to the outside of the rotating hole and is provided with a switching handle; the left switching hole, the front switching hole and the rear switching hole are all provided with a tubular sealing member; the upper end of the sealing member protrudes upward into the oil circuit switching groove and fits with the lower surface of the switching head; an oil-passing gap is provided between the lower surface of the switching head and the bottom of the oil circuit switching groove; a third oil hole is provided on the front side of the lower surface of the left part of the switching head; a fourth oil hole connected with the third oil hole is provided on the rear side of the lower surface of the left part of the switching head.

[0008] A second high-pressure oil circuit intersecting with the first high-pressure oil circuit and a second low-pressure oil circuit intersecting with the first low-pressure oil circuit are provided on the front side of the right end face of the cylinder; a third high-pressure oil circuit intersecting with the second high-pressure oil circuit is provided on the side wall of the front side of the cylinder; a high-pressure valve mounting hole is provided on the rear side of the right end face of the cylinder; a high-pressure valve matching it is provided in the high-pressure valve mounting hole; a fourth high-pressure oil circuit intersecting with the rear end of the third high-pressure oil circuit is provided at the center of the bottom of the high-pressure valve mounting hole; a fifth high-pressure oil circuit intersecting with the third high-pressure oil circuit is provided at the center of the bottom of the left switching hole; a second connecting oil circuit intersecting with the return oil circuit is provided at the center of the bottom of the rear switching hole; the bottom of the front switching hole is connected with the ejection oil circuit through the third connecting oil circuit; the right end port of the ejection oil circuit is provided on the right end face of the cylinder, and the left end face of the oil supply seat shields and seals the right end port of the ejection oil circuit.

[0009] A low-pressure valve mounting hole is provided in the middle of the lower side of the right end surface of the cylinder; a low-pressure valve matching it is provided in the low-pressure valve mounting hole; a third low-pressure oil circuit connected with the lower end of the fifth high-pressure oil circuit is provided at the center of the bottom of the low-pressure valve mounting hole; the right switching hole is connected with the third low-pressure oil circuit through the sixth high-pressure oil circuit; a first auxiliary oil circuit connected with the sixth high-pressure oil circuit is provided on the right end surface of the cylinder; a fourth low-pressure oil circuit connected with the third low-pressure oil circuit is provided on the front side wall of the lower right end of the cylinder; a fifth low-pressure oil circuit connected with the fourth low-pressure oil circuit is provided on the lower surface of the right end of the cylinder; the upper end of the fifth low-pressure oil circuit is connected with the left end of the second low-pressure oil circuit.

[0010] The limiting block and the bottom of the limiting groove, and the oil delivery seat and the oil cylinder are all fixed by a plurality of evenly distributed screws.

[0011] The beneficial effects of the utility model are:

[0012] Compared with the prior art, the manual hydraulic double-tooth expansion shearing device adopting the structure of the utility model can use the pressure of the hydraulic oil to return the ejected piston through the cooperation of the return oil circuit and the oil inlet groove. During the entire return process, no spring is required. As the spring structure is removed, the space originally used to accommodate the spring can be removed from the inside of the oil cylinder, effectively reducing the volume of the oil cylinder, thereby effectively reducing the volume of the expansion shearing device, facilitating the movement and use of the expansion shearing device. When the hydraulic oil pushes the piston, without the participation of the spring, the pressure of the hydraulic oil can act on the piston completely and will not be eliminated by the elastic opposition of the spring, thereby ensuring the shearing force of the expansion shearing device to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view of the first angle of the manual hydraulic double-tooth expansion shear of the utility model;

[0014] Figure 2 yes Figure 1 An enlarged view of part A;

[0015] Figure 3 It is a cross-sectional view of the second angle of the manual hydraulic double-tooth expansion shear of the utility model;

[0016] Figure 4 This is the cross-sectional view of the cylinder at the first angle;

[0017] Figure 5 This is the cross-sectional view of the cylinder from the second angle;

[0018] Figure 6 It is a cross-sectional view of the cylinder at the third angle;

[0019] Figure 7 This is the cross-sectional view of the cylinder at the fourth angle;

[0020] Figure 8 It is the cross-sectional view of the oil cylinder at the fifth angle;

[0021] Fig. 9 This is the cross-sectional view of the oil cylinder at the sixth angle;

[0022] Fig.10 It is a structural diagram of the oil cylinder;

[0023] Fig.11 It is a schematic diagram of the structure of the switching head at one angle;

[0024] Fig.12 This is a schematic diagram of the structure of the switching head from another angle;

[0025] Fig.13 It is a cross-sectional view of the third angle of the manual hydraulic double-tooth expansion shear of the utility model. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0027] See also Figures 1 to 13The utility model provides a manual hydraulic double-tooth expansion shear, comprising an oil cylinder 1, a piston chamber 2 arranged at the center of the left end face of the oil cylinder 1, a piston 3 matched therewith arranged in the piston chamber 2, a piston rod 4 arranged at the center of the left end face of the piston 3, an expansion shear pliers assembly 5 connected to the left end of the piston rod 4, an oil tank 6 arranged at the rear end of the oil cylinder 1, an oil tank cap 7 matched therewith is covered at the rear end port of the oil tank 6, an oil circuit switching groove 8 is arranged on the upper surface of the rear part of the oil cylinder 1; an oil circuit switching device matched therewith is arranged in the oil circuit switching groove 8 The piston chamber 2 is provided with an ejection oil passage 9 on the right side of the chamber wall and the ejection oil passage 9 is connected with the oil passage switching groove 8; the inner wall of the left end of the piston chamber 2 is provided with an annular oil inlet groove 10, and the piston 3 is located on the right side of the oil inlet groove 10; the right side of the oil inlet groove 10 is provided with a return oil passage 11 connected with the oil passage switching groove 8; the front side of the right end of the oil cylinder 1 is provided with an oil delivery device located in the oil tank 6; the oil delivery device includes an oil pressure head 12, the right end of the oil pressure head 12 passes through the oil tank cover 7 to the right and is provided with a movable handle 13.

[0028] The oil delivery device includes an oil delivery seat 14 arranged on the front side of the right end face of the oil cylinder 1; a sealing hole 15 corresponding to the position of the oil delivery seat 14 is provided on the oil tank cover 7, and the right end of the oil delivery seat 14 is embedded in the sealing hole 15; a pressure oil groove 16 matching the oil pressure head 12 is provided at the center of the right end face of the oil delivery seat 14; a first low-pressure oil path 17 connected to the bottom of the pressure oil groove 16 is provided on the lower side of the left end face of the oil delivery seat 14; an embedding hole 18 is provided at the center of the bottom of the pressure oil groove 16; a central oil pipe 19 matching it is provided in the embedding hole 18; an auxiliary oil groove 20 is provided at the center of the left end face of the oil pressure head 12, The right end of the core oil tube 19 penetrates into the auxiliary oil groove 20; an oil inlet gap 21 is provided between the left end face of the center oil tube 19 and the bottom of the embedded hole 18; an upper oil suction hole 22 communicating with the oil inlet gap 21 is provided on the rear side wall of the oil delivery seat 14; a first high-pressure oil circuit 23 communicating with the upper oil suction hole 22 is provided on the upper side of the left end face of the oil delivery seat 14; a lower oil suction hole 24 communicating with the first low-pressure oil circuit 17 is provided on the rear side wall of the oil delivery seat 14; a first connecting oil circuit 25 is provided on the upper surface of the oil delivery seat 14; the first high-pressure oil circuit 23 is communicated with the first low-pressure oil circuit 17 through the first connecting oil circuit 25.

[0029] The oil circuit switching device includes a left switching hole 26 arranged at the left center of the bottom of the oil circuit switching groove 8, a front switching hole 27 arranged at the front side of the middle of the bottom of the oil circuit switching groove 8, a rear switching hole 28 arranged at the rear side of the middle of the bottom of the oil circuit switching groove 8, and a right switching hole 29 arranged at the right center of the bottom of the oil circuit switching groove 8; a limit groove 30 is arranged on the inner wall of the upper groove of the oil circuit switching groove 8; a limit block 31 matching with it is arranged in the limit groove 30; a rotating hole 32 is arranged at the center of the limit block 31; a switching rod 33 matching with it is arranged in the rotating hole 32; the lower end of the switching rod 33 passes downward to the rotating hole 32 and is provided with A switching head 34 that matches the oil circuit switching groove 8; the upper end of the switching rod extends upward to the outside of the rotating hole 32 and is provided with a switching handle 35; the left switching hole 26, the front switching hole 27 and the rear switching hole 28 are all provided with a tubular sealing member 36; the upper end of the sealing member 36 protrudes upward into the oil circuit switching groove 8 and fits with the lower surface of the switching head 34; an oil-passing gap 37 is provided between the lower surface of the switching head 34 and the bottom of the oil circuit switching groove 8; a third oil hole 38 is provided on the front side of the lower surface of the left part of the switching head 34; a fourth oil hole 39 that is connected with the third oil hole 38 is provided on the rear side of the lower surface of the left part of the switching head 34.

[0030] The front side of the right end face of the oil cylinder 1 is provided with a second high-pressure oil circuit 40 intersecting with the first high-pressure oil circuit 23, and a second low-pressure oil circuit 41 intersecting with the first low-pressure oil circuit 17; the front side wall of the oil cylinder 1 is provided with a third high-pressure oil circuit 42 intersecting with the second high-pressure oil circuit 40; the rear side of the right end face of the oil cylinder 1 is provided with a high-pressure valve mounting hole 43; a high-pressure valve matching with it is arranged in the high-pressure valve mounting hole 43; the center of the bottom of the high-pressure valve mounting hole 43 is provided with a high-pressure valve connecting with the third high-pressure oil circuit 42 A fourth high-pressure oil circuit 45 is connected to the rear ends; a fifth high-pressure oil circuit 46 connected to the third high-pressure oil circuit 42 is provided at the center of the bottom of the left switching hole 26; a second connecting oil circuit 47 connected to the return oil circuit 11 is provided at the center of the bottom of the rear switching hole 28; the bottom of the front switching hole 27 is connected to the ejection oil circuit 9 through the third connecting oil circuit 48; the right end port of the ejection oil circuit 9 is provided on the right end surface of the cylinder 1, and the left end surface of the oil supply seat 14 shields and seals the right end port of the ejection oil circuit 9.

[0031] A low-pressure valve mounting hole 49 is provided in the middle of the lower side of the right end surface of the oil cylinder 1; a low-pressure valve 50 matching it is provided in the low-pressure valve mounting hole 49; a third low-pressure oil circuit 51 which is connected to the lower end of the fifth high-pressure oil circuit 46 is provided at the center of the bottom of the low-pressure valve mounting hole 49; the right switching hole 29 is connected to the third low-pressure oil circuit 51 through the sixth high-pressure oil circuit 52; a first auxiliary oil circuit 53 which is connected to the sixth high-pressure oil circuit 52 is provided on the right end surface of the oil cylinder 1; a fourth low-pressure oil circuit 54 which is connected to the third low-pressure oil circuit 51 is provided on the front side wall of the lower right end of the oil cylinder 1; a fifth low-pressure oil circuit 55 which is connected to the fourth low-pressure oil circuit 54 is provided on the lower surface of the right end of the oil cylinder 1; the upper end of the fifth low-pressure oil circuit 55 is connected to the left end of the second low-pressure oil circuit 41.

[0032] The limiting block 31 and the bottom of the limiting groove 30 , as well as the oil feeding seat 14 and the oil cylinder 1 are fixed by a plurality of evenly distributed screws 56 .

[0033] The method of using the utility model is as follows:

[0034] Firstly, the ports of the return oil circuit 11, the first auxiliary oil circuit 53, and the ejection oil circuit 9 on the right end surface of the oil cylinder 1, as well as the ports of the fourth low-pressure oil circuit 54, the fifth low-pressure oil circuit 55, and the third high-pressure oil circuit 42 on the outer peripheral surface of the oil cylinder 1 can be blocked by the plug 62, and at the same time, the port of the first connecting oil circuit 25 on the upper surface of the oil delivery seat 14 can be blocked by the plug, so as to ensure that no oil leakage occurs in each oil circuit, and the plug can be screwed and fixed by means of threaded connection.

[0035] The oil tank 6 is filled with hydraulic oil, and the upper oil suction hole 22 and the lower oil suction hole 24 are both provided with a conventional one-way structure, which is a steel ball 63. The steel ball 63 only needs to be placed in the upper oil suction hole 22 and the lower oil suction hole 24, and then an oil suction nozzle is screwed to the orifice of the upper oil suction hole 22 and the orifice of the lower oil suction hole 24, ensuring that the inner diameter of the oil suction nozzle is smaller than the steel ball, and at the same time ensuring that the diameter of the steel ball is larger than the diameter of the first high-pressure oil circuit 23 and the diameter of the first low-pressure oil circuit 17. When the movable handle 13 pulls the oil pressure head 12 to the right, the oil pressure head 12 moves backward, and the orifices of the upper oil suction hole 22 and the lower oil suction hole 24 will generate suction to push the steel ball inward. At this time, the upper oil suction hole 22 and the lower oil suction hole 24 are both in an open state, and the hydraulic oil entering the upper oil suction hole 22 will enter the central oil pipe 19 through the oil inlet gap 21, and then enter the auxiliary The hydraulic oil in the oil tank 20 and the lower oil suction hole 24 will enter the oil pressure tank 16 through the first low-pressure oil path 17. When the piston 3 needs to be pushed out of the piston chamber 2, the oil pressure head 12 can be pushed to the left by the movable handle 13. At this time, the oil pressure head 12 will move to the left along the trajectory of the oil pressure tank 16. The hydraulic oil in the oil pressure tank 16 is squeezed to the left by the oil pressure head 12, and the hydraulic oil in the auxiliary oil tank 20 is squeezed to the left by the oil pressure head 12. At this time, the oil pressure tank The hydraulic oil in 16 is squeezed into the first low-pressure oil circuit 17, and the hydraulic oil in the auxiliary oil groove 20 is squeezed into the first high-pressure oil circuit 23. Under the action of oil pressure, when the hydraulic oil passes through the first high-pressure oil circuit 23 and the first low-pressure oil circuit 17, the steel ball will be pushed by the hydraulic oil to block and seal the oil suction nozzles screwed on the orifices of the upper oil suction hole 22 and the lower oil suction hole 24, so that the hydraulic oil will not return to the oil tank through the upper oil suction hole 22 and the lower oil suction hole 24.

[0036] The hydraulic oil entering the first high-pressure oil circuit 23 will enter the third high-pressure oil circuit 42 through the second high-pressure oil circuit 40, and then enter the fifth high-pressure oil circuit 46. When the high-pressure valve arranged in the high-pressure valve mounting hole 43 and the low-pressure valve 50 arranged in the low-pressure valve mounting hole 49 are not opened, the hydraulic oil entering the fifth high-pressure oil circuit 46 will flow upward into the left switching hole 26. The high-pressure valve and the low-pressure valve 50 are both existing valves, and a preset pressure can be set. When this preset pressure is reached, the high-pressure valve and the low-pressure valve 50 will both open. When the hydraulic oil enters the left switching hole 26, the switching handle 35 can be rotated to make the switching handle 35 drive the switching head 34 to rotate through the switching rod 33, so that the third oil hole 38 is connected to the front switching hole 27, and the fourth oil The hole 39 is connected with the left switching hole 26. At this time, the fifth oil hole 60 and the sixth oil hole 61 are located on the left and right sides of the rear switching hole 28. The upper end surface of the seal 36 in the rear switching hole 28 is in contact with the lower surface of the switching head 34, and the rear switching hole 28 is in a closed state. As the hydraulic oil enters the left switching hole 26, the hydraulic oil will successively pass through the fourth oil hole 39 and the third oil hole 38 to enter the front switching hole 27. When the right end port of the ejection oil circuit is shielded and sealed by the left end surface of the oil delivery seat, the hydraulic oil entering the front switching hole will successively pass through the third connecting oil circuit 48 and the ejection oil circuit 9 to enter the piston chamber 2, pushing the piston 3 to the left, so that the piston 3 drives the piston rod 4 to move stably to the left along the trajectory of the piston chamber 2, thereby realizing the double-clamp closed shearing of the expansion shearing pliers assembly 5.

[0037] At the same time, the hydraulic oil entering the first low-pressure oil circuit 17 will enter the fifth low-pressure oil circuit 55 through the second low-pressure oil circuit 41, and then enter the third low-pressure oil circuit 51 through the fourth low-pressure oil circuit 54, and the third low-pressure oil circuit 51 is connected through the lower end of the fifth high-pressure oil circuit 46, and the fifth high-pressure oil circuit 46 is connected with the left switching hole 26. When the low-pressure valve 50 is not opened, the hydraulic oil entering the third low-pressure oil circuit 51 will successively pass through the fifth high-pressure oil circuit 46, the left switching hole 26, the fourth oil hole 39, the third oil hole 38, the front switching hole 27, the third connecting oil circuit 48, and the ejection oil circuit 9 into the piston chamber 2, pushing the piston 3 to the left, thereby forming an effect in which both hydraulic oils push the piston 3. When the pressure of the two hydraulic oils acts on the piston 3, the effect of high pressure pushing the piston 3 can be achieved, effectively ensuring the shear force of the expansion shear pliers assembly 5 during double-clamp closed shearing.

[0038] When the double pliers of the expansion shearing pliers assembly 5 need to be opened, it is only necessary to make the piston 3 drive the piston rod 4 to move back to the right position. At this time, the switching head 34 can be rotated by the switching handle 35 to make the third oil hole 38 interpenetrate with the left switching hole 26, and the fourth oil hole 39 interpenetrate with the rear switching hole 28. At this time, as the movable handle 13 drives the oil pressure head 12 to press to the left, the hydraulic oil flowing out of the first low-pressure oil circuit 17 and the first high-pressure oil circuit 23 eventually enters the left switching hole 26 through the fifth high-pressure oil circuit 46, and then enters the rear switching hole 28 through the third oil hole 38 and the fourth oil hole 39, and enters The hydraulic oil in the rear switching hole 28 will flow into the return oil circuit 11 through the second connecting oil circuit 47, and then fill the left side of the piston 3 through the oil inlet groove 10. Under the continuous push of the subsequent hydraulic oil, the piston 3 will be pushed to the right to achieve reset. When the piston 3 moves to the right, the hydraulic oil in the piston chamber 2 will be squeezed back into the top outlet oil circuit 9. As the hydraulic oil in the piston chamber 2 is squeezed, the oil pressure will rise accordingly. When the oil pressure reaches the preset pressure of the high-pressure valve, the high-pressure valve opens, and the hydraulic oil will directly release pressure and discharge the hydraulic oil into the oil tank 6 again to achieve the recycling of the hydraulic oil.

[0039] From the above, it can be known that the utility model can use the pressure of the hydraulic oil to return the ejected piston 3 through the cooperation of the return oil circuit 11 and the oil inlet groove 10. During the entire return process, no spring is required. As the spring structure is removed, the space originally used to accommodate the spring can be removed from the inside of the cylinder 1, thereby effectively reducing the volume of the cylinder, thereby effectively reducing the volume of the expansion shear, and facilitating the movement and use of the expansion shear. When the hydraulic oil pushes the piston 3, in the absence of a spring, the pressure of the hydraulic oil can fully act on the piston 3 and will not be eliminated by the elastic resistance of the spring, thereby ensuring the shear force of the expansion shear to the greatest extent.

[0040] During actual use, the first high-pressure oil circuit 23 and the first low-pressure oil circuit 17 discharge oil at the same time. When the staff presses the oil head 12 through the movable handle 13, the resistance force encountered will be relatively large, which makes it difficult for the staff to frequently operate the movable handle. Therefore, according to actual needs, only one oil circuit needs to be opened, and the hydraulic oil in the other oil circuit can be returned to the oil tank 6 through the low-pressure valve 50. At this time, it is only necessary to set the preset pressure of the low-pressure valve according to actual needs.

[0041] A ring-shaped groove 57 is provided on the front side wall of the switching head 34, a first oil hole 58 is provided on the front side of the inner circumference of the groove 57, a second oil hole 59 connected with the first oil hole 58 is provided on the front side of the lower surface of the switching head 34, a third oil hole 38 is provided on the front side of the lower surface of the left portion of the switching head 34, a fourth oil hole 39 connected with the third oil hole 38 is provided on the rear side of the lower surface of the left portion of the switching head 34, a fifth oil hole 60 is provided on the front side of the lower surface of the right portion of the switching head 34, a sixth oil hole 61 connected with the fifth oil hole 60 is provided on the rear side of the lower surface of the right portion of the switching head 34, the fifth oil hole 60 and the sixth oil hole 61 are symmetrically distributed with the third oil hole 38 and the fourth oil hole 39, thereby increasing the switching angle of the switching head 34, and the staff can rotate the switching direction according to their own operating habits, which is more conducive to the switching work.

[0042] The limit block 31 and the bottom of the limit groove 30, and the oil supply seat 14 and the oil cylinder 1 are fixed by a plurality of evenly distributed screws 56. This fixing method facilitates the disassembly and assembly of the limit block 31 and the oil supply seat 14, thereby facilitating the maintenance and replacement of components.

Claims

1. A manual hydraulic double-tooth expansion shear, comprising an oil cylinder, a piston cavity arranged at the center of the left end face of the oil cylinder, a piston matching therewith arranged in the piston cavity, a piston rod arranged at the center of the left end face of the piston, an expansion shear pliers assembly connected to the left end of the piston rod, an oil tank arranged at the rear end of the oil cylinder, and an oil tank cap matching therewith arranged at the rear end port of the oil tank, characterized in that: An oil circuit switching groove is provided on the upper surface of the rear part of the oil cylinder; an oil circuit switching device matching with it is provided in the oil circuit switching groove; an ejection oil circuit communicating with the oil circuit switching groove is provided on the right cavity wall of the piston cavity; an annular oil inlet groove is provided on the inner wall of the left end port of the piston cavity, and the piston is located on the right side of the oil inlet groove; a return oil circuit communicating with the oil circuit switching groove is provided on the right groove wall of the oil inlet groove; an oil delivery device located in the oil tank is provided on the front side of the right end face of the oil cylinder; the oil delivery device includes an oil pressure head, the right end of which passes through the oil tank cover to the right and is provided with a movable handle.

2. A manual hydraulic double-tooth expansion shear according to claim 1, characterized in that: The oil delivery device includes an oil delivery seat arranged on the front side of the right end face of the oil cylinder; a sealing hole corresponding to the position of the oil delivery seat is arranged on the oil tank cover, and the right end of the oil delivery seat is embedded in the sealing hole; an oil pressure groove matching the oil pressure head is arranged at the center of the right end face of the oil delivery seat; a first low-pressure oil circuit connected to the bottom of the oil pressure groove is arranged at the lower side of the left end face of the oil delivery seat; an embedding hole is arranged at the center of the bottom of the oil pressure groove; a central oil pipe matching the same is arranged in the embedding hole; an auxiliary oil groove is arranged at the center of the left end face of the oil pressure head, The right end of the center oil pipe penetrates into the auxiliary oil groove; there is an oil inlet gap between the left end face of the center oil pipe and the bottom of the embedded hole; an upper oil suction hole is provided on the rear side wall of the oil delivery seat and is connected to the oil inlet gap; a first high-pressure oil circuit is provided on the upper side of the left end face of the oil delivery seat and is connected to the upper oil suction hole; a lower oil suction hole is provided on the rear side wall of the oil delivery seat and is connected to the first low-pressure oil circuit; a first connecting oil circuit is provided on the upper surface of the oil delivery seat; the first high-pressure oil circuit and the first low-pressure oil circuit are connected through the first connecting oil circuit.

3. A manual hydraulic double-tooth expansion shear according to claim 2, characterized in that: The oil circuit switching device comprises a left switching hole arranged at the left center of the bottom of the oil circuit switching groove, a front switching hole arranged at the front side of the middle of the bottom of the oil circuit switching groove, a rear switching hole arranged at the rear side of the middle of the bottom of the oil circuit switching groove, and a right switching hole arranged at the right center of the bottom of the oil circuit switching groove; a limit groove is arranged on the inner wall of the notch on the upper side of the oil circuit switching groove; a limit block matching with it is arranged in the limit groove; a rotating hole is arranged at the center of the limit block; a switching rod matching with it is arranged in the rotating hole; the lower end of the switching rod passes downward to the rotating hole and A switching head matching the oil circuit switching groove is provided; the upper end of the switching rod passes upward to the outside of the rotating hole and is provided with a switching handle; the left switching hole, the front switching hole and the rear switching hole are all provided with a tubular sealing member; the upper end of the sealing member protrudes upward into the oil circuit switching groove and fits with the lower surface of the switching head; an oil-passing gap is provided between the lower surface of the switching head and the bottom of the oil circuit switching groove; a third oil hole is provided on the front side of the lower surface of the left part of the switching head; a fourth oil hole connected with the third oil hole is provided on the rear side of the lower surface of the left part of the switching head.

4. A manual hydraulic double-tooth expansion shear according to claim 3, characterized in that: A second high-pressure oil circuit intersecting with the first high-pressure oil circuit and a second low-pressure oil circuit intersecting with the first low-pressure oil circuit are provided on the front side of the right end face of the cylinder; a third high-pressure oil circuit intersecting with the second high-pressure oil circuit is provided on the side wall of the front side of the cylinder; a high-pressure valve mounting hole is provided on the rear side of the right end face of the cylinder; a high-pressure valve matching it is provided in the high-pressure valve mounting hole; a fourth high-pressure oil circuit intersecting with the rear end of the third high-pressure oil circuit is provided at the center of the bottom of the high-pressure valve mounting hole; a fifth high-pressure oil circuit intersecting with the third high-pressure oil circuit is provided at the center of the bottom of the left switching hole; a second connecting oil circuit intersecting with the return oil circuit is provided at the center of the bottom of the rear switching hole; the bottom of the front switching hole is connected with the ejection oil circuit through the third connecting oil circuit; the right end port of the ejection oil circuit is provided on the right end face of the cylinder, and the left end face of the oil supply seat shields and seals the right end port of the ejection oil circuit.

5. A manual hydraulic double-tooth expansion shear according to claim 4, characterized in that: A low-pressure valve mounting hole is provided in the middle of the lower side of the right end surface of the cylinder; a low-pressure valve matching it is provided in the low-pressure valve mounting hole; a third low-pressure oil circuit connected with the lower end of the fifth high-pressure oil circuit is provided at the center of the bottom of the low-pressure valve mounting hole; the right switching hole is connected with the third low-pressure oil circuit through the sixth high-pressure oil circuit; a first auxiliary oil circuit connected with the sixth high-pressure oil circuit is provided on the right end surface of the cylinder; a fourth low-pressure oil circuit connected with the third low-pressure oil circuit is provided on the front side wall of the lower right end of the cylinder; a fifth low-pressure oil circuit connected with the fourth low-pressure oil circuit is provided on the lower surface of the right end of the cylinder; the upper end of the fifth low-pressure oil circuit is connected with the left end of the second low-pressure oil circuit.

6. A manual hydraulic double-tooth expansion shear according to claim 3, characterized in that: The limiting block and the bottom of the limiting groove, and the oil delivery seat and the oil cylinder are all fixed by a plurality of evenly distributed screws.

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