An overstroke automatic pressure relief stretcher

Abstract

The application discloses an overstroke automatic pressure relief stretcher and belongs to the technical field of hydraulic stretchers. The overstroke automatic pressure relief stretcher comprises a cylinder body and a piston, an oil cavity is formed between the cylinder body and the piston, a central guide sleeve is connected in the piston, the end of the central guide sleeve extends into a hollow cavity of the cylinder body, and a pressure relief assembly is arranged between the central guide sleeve and the cylinder body. The pressure relief assembly comprises a pressure relief rod arranged in a pressure relief channel and a sealing ring sleeved on the pressure relief rod. The pressure relief channel is arranged on the cylinder body and communicates with the oil cavity. In addition, the pressure relief rod is provided with a reset spring. During the working of the stretcher, the pressure relief rod is relatively displaced with the sealing ring under the driving of the central guide sleeve, and a gap is formed between the sealing ring and a pressure relief groove on the pressure relief rod, so that the automatic pressure relief during the overstroke is realized. After the pressure relief is completed, the pressure relief rod is pushed back to the initial position under the pushing of the reset spring, so as to be used next time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydraulic tensioners, and more particularly relates to an overstroke automatic pressure relief tensioner. BACKGROUND

[0002] A hydraulic bolt tensioner, referred to as a hydraulic tensioner, has the functions of bolt fastening and dismounting. It can be widely used in the industries of metallurgy and mining, petroleum and chemical industry, shipbuilding industry, power system, locomotive and vehicle, heavy machinery, etc. The hydraulic tensioner uses the hydraulic power provided by an ultra-high pressure pump to stretch the bolt within the elastic deformation range of the material, so as to achieve the purpose of fastening or dismounting the bolt.

[0003] Although the specifications of the hydraulic tensioner are various, each type of tensioner has its own stroke range. If the overstroke operation is performed, the parts in the tensioner will be damaged, and even a safety accident will occur. The overstroke protection of the existing tensioner is generally realized by a preset warning line. This method is very troublesome, and the workers need to pay attention to the warning line at all times. In actual operation, if the workers are not careful, the tensioner will be overstroke. Therefore, it is necessary for the tensioner to be able to automatically relieve pressure under overstroke.

[0004] Through retrieval, it is found that the application No. 201520706889.5 discloses an overstroke automatic protection tensioner. The application includes a base, a joint, a cylinder, a piston, a pull rod, and an end cover. The base and the cylinder are connected in an up-down manner. The pull rod is arranged in the cylinder. The cylinder and the pull rod are provided with the piston which cooperates with both of them in a radial direction. The pull rod and the piston are both in a stepped shape. The pull rod is provided with a warning mark groove. The end cover is fixedly connected to the cylinder. The application further includes an overflow device and a large spring. The end cover, the pull rod, the piston, and the cylinder form a closed cavity. A ring of large springs is arranged in the cavity. An overflow device is arranged between any two large springs. The overflow device includes a plug, a small spring, a steel ball, and a top rod. When the stretching reaches the designed stroke, the top rod contacts the end cover, generates a downward force to push away the steel ball, causes the oil in the cylinder to overflow, and the piston no longer moves upward, so that the sealing element and the parts are not damaged, and the service life of the tensioner is prolonged. However, the machining precision of the steel ball and the stepped hole stepped surface is high in the application. After the pressure relief is completed, the steel ball is not easy to be centered in the resetting process, and the sealing failure is easy to occur. SUMMARY

[0005] 1. Problem to be solved

[0006] In view of at least some problems existing in the prior art, the present application provides an automatic pressure relief tensioner. The technical scheme of the present application not only can automatically relieve pressure when the overstroke is performed, but also can automatically reset the pressure relief rod for repeated use after the pressure relief is completed, and does not affect the sealing effect of the pressure relief rod itself.

[0007] 2、Technical solutions

[0008] To solve the above problems, the technical solutions adopted by the present application are as follows:

[0009] The overstroke automatic pressure relief stretcher of the present application comprises a cylinder body and a piston, an oil cavity is formed between the cylinder body and the piston, a central guide sleeve is connected in the piston, the end of the central guide sleeve extends into the hollow cavity of the cylinder body, and a pressure relief assembly is arranged between the central guide sleeve and the cylinder body, which is used for automatic pressure relief during overstroke.

[0010] Further, the pressure relief assembly comprises a pressure relief rod in a pressure relief channel and a sealing ring sleeved on the pressure relief rod, the pressure relief channel is arranged on the cylinder body and communicates with the oil cavity, the pressure relief rod relatively displaces between the central guide sleeve and the sealing ring, and a gap is generated between the sealing ring and a pressure relief groove on the pressure relief rod, so that automatic pressure relief during overstroke is realized.

[0011] Further, the bottom of the central guide sleeve is provided with a first convex ring arranged along the circumference, and a push rod for pushing the pressure relief rod is arranged on the first convex ring.

[0012] Further, the pressure relief channel is arranged parallel to the central axis of the cylinder body, and is a stepped through hole with a small upper part and a large lower part, and a first limiting groove for accommodating the sealing ring is processed on the small diameter section.

[0013] Further, a first elastic member is sleeved on the pressure relief rod, and the first elastic member is limited between the stepped surface of the pressure relief channel and a second convex ring on the pressure relief rod.

[0014] Further, a screw plug is arranged in the pressure relief channel, the screw plug is located at the bottom of the pressure relief rod, and a through hole is arranged on the screw plug for the free end of the push rod to pass through.

[0015] Further, a stretching nut is arranged on the piston, the stretching nut comprises a first half nut and a second half nut, and the two nuts are connected by a connecting rod; a second limiting groove is arranged on the connecting rod and matches the limiting member on the first half nut.

[0016] Further, a first mounting hole is arranged on the first half nut for the connecting rod to pass through, and a second mounting hole is arranged on the second half nut for the connecting rod to insert.

[0017] Further, a limiting portion matched with the first mounting hole is arranged at one end of the connecting rod, and a connecting portion matched with the second mounting hole is arranged at the other end of the connecting rod.

[0018] Further, the connecting rod is sleeved with a second elastic member, wherein the first mounting hole and the second mounting hole are both stepped holes, and the second elastic member is limited between the stepped surfaces of the two stepped holes.

[0019] Further, the limiting member comprises a fixing sleeve, a third elastic member and a steel ball, wherein the third elastic member and the steel ball are both located in the fixing sleeve, and the third elastic member is located between the top wall of the fixing sleeve and the steel ball.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the beneficial effects of the present application are:

[0022] (1) The piston is connected with a center guide sleeve, and a pressure relief assembly is arranged between the center guide sleeve and the cylinder body. The pressure relief assembly comprises a pressure relief rod, a sealing ring and a push rod, and the pressure relief rod is provided with a pressure relief groove. During operation, the piston moves upward, driving the push rod to move upward synchronously through the center guide sleeve. Since there is a certain distance between the push rod and the pressure relief rod, the pressure relief rod does not work within the normal stroke range. When the piston is overstroke, the push rod pushes the pressure relief rod to move upward. Since the sealing ring is axially limited in the pressure relief channel, a certain displacement is generated between the sealing ring and the pressure relief rod. When the pressure relief groove moves to the sealing ring, a gap is generated between them, and the pressure relief work is completed, thereby protecting the stretcher.

[0023] (2) The pressure relief rod is sleeved with a first elastic member, which is limited between the stepped surface of the pressure relief channel and the second protruding ring on the pressure relief rod. When the pressure relief rod is pushed to move upward, the first elastic member is extruded. After the pressure relief is completed, the restoring force of the first elastic member drives the pressure relief rod to return to the initial position. At this time, there is no contact between the sealing ring and the pressure relief groove, and the sealing state is restored to facilitate the next overstroke protection.

[0024] (3) The stretching nut comprises a first half nut and a second half nut, and the two nuts are connected through a connecting rod. The first half nut is provided with a limiting member, and the connecting rod is provided with a second limiting groove. Through the cooperation of the limiting member and the second limiting groove, the stretching nut and the bolt to be stretched can be quickly assembled and disassembled, which can greatly improve the assembly efficiency, and is particularly suitable for the disassembly and assembly of bolts in some special environments. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a whole structure schematic view of the overstroke automatic pressure relief stretcher.

[0026] Figure 2This is a cross-sectional view of the pressure relief assembly in this invention;

[0027] Figure 3 This is a schematic diagram of the structure of the central guide sleeve in this invention;

[0028] Figure 4 This is an exploded view of the pressure relief assembly in this invention;

[0029] Figure 5 This is a cross-sectional view of the cylinder block in this invention;

[0030] Figure 6 This is a cross-sectional view of the tension nut in this invention;

[0031] Figure 7 for Figure 6 A magnified view of a portion of point A in the middle.

[0032] In the diagram: 1. Cylinder block; 11. Pressure relief channel; 12. First limiting groove; 2. Piston; 3. Central guide sleeve; 31. First convex ring;

[0033] 4. Pressure relief assembly; 41. Pressure relief rod; 411. Pressure relief groove; 412. Second convex ring; 42. Sealing ring; 43. Push rod; 44. First elastic element; 45. Screw plug;

[0034] 5. Tension nut; 51. First half nut; 52. Second half nut; 53. First mounting hole; 54. Second mounting hole;

[0035] 6. Connecting rod; 61. Limiting part; 62. Connecting part; 63. Second limiting groove; 64. Second elastic element;

[0036] 7. Limiting component; 71. Fixing sleeve; 72. Third elastic component; 73. Steel ball; 8. Support sleeve; 9. Internal hexagon socket sleeve. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments.

[0038] Example 1

[0039] like Figure 1 As shown, this embodiment of an overtravel automatic pressure relief tensioner includes a cylinder 1, a piston 2, and a support sleeve 8. The piston 2 is slidably disposed within the cylinder 1, and a tension nut 5 is fitted to the top of the piston 2. An oil chamber is formed between the piston 2 and the cylinder 1, and a cylinder seal is provided between them.

[0040] In addition, the cylinder body 1 is equipped with a quick connector, through which oil is supplied to the oil chamber to provide power for the movement of the piston 2. The support sleeve 8 is connected to the bottom of the cylinder body 1, and the support sleeve 8 is equipped with an internal hexagonal socket 9.

[0041] As Figure 2 shown, the piston 2 is connected with a center guide sleeve 3, the end of the center guide sleeve 3 extends into the hollow cavity of the cylinder 1. The center guide sleeve 3 is provided with a pressure relief assembly 4 between the cylinder 1, which can automatically relieve pressure when the piston 2 over-travels, to provide protection for the stretcher.

[0042] As Figure 3 shown, the center guide sleeve 3 is a hollow cylindrical shape, and the outer peripheral wall of both ends of the center guide sleeve 3 is provided with a first convex ring 31. Among them, the upper convex ring is used for connecting with the inner wall of the piston 2; the lower convex ring provides a mounting base for the push rod 43 of the pressure relief assembly 4.

[0043] As Figure 5 shown, the cylinder 1 is provided with a pressure relief channel 11 parallel to the central axis of the cylinder 1, and the pressure relief channel 11 is in communication with the oil cavity formed between the cylinder 1 and the piston 2. The pressure relief channel 11 is a stepped hole with a small upper diameter and a large lower diameter, and a first limiting groove 12 is formed on the small diameter section. Through the cooperation between the pressure relief channel 11 and the pressure relief assembly 4, the pressure relief work during over-travel is completed. Preferably, the pressure relief channel 11 is symmetrically provided with two, and of course, the corresponding pressure relief assembly 4 is also provided with two groups.

[0044] Specifically, as Figure 4 shown, the pressure relief assembly 4 includes a pressure relief rod 41, a sealing ring 42, a push rod 43, a first elastic member 44, and a plug 45. Among them, the pressure relief rod 41 is located in the pressure relief channel 11, and the pressure relief rod 41 is provided with a pressure relief groove 411, and the outer peripheral wall of the end thereof is provided with a second convex ring 412.

[0045] The sealing ring 42 is sleeved on the push rod 43 and is axially limited in the first limiting groove 12 on the pressure relief channel 11. That is, the sealing ring 42 and the pressure relief rod 41 can move relative to each other, when the sealing ring 42 and the non-pressure relief groove 411 part of the pressure relief rod 41 are in contact, the two are in sealing connection; when the sealing ring 42 and the pressure relief groove 411 are in contact, there is a certain gap between them, so as to achieve the purpose of pressure relief.

[0046] One end of the push rod 43 is arranged on the lower convex ring of the center guide sleeve 3 and moves synchronously with the center guide sleeve 3 to push the upward movement of the pressure relief rod 41 to relieve pressure. There is a certain distance between the free end of the push rod 43 and the bottom of the pressure relief rod 41, which is the safe travel distance of the stretcher.

[0047] The screw plug 45 is arranged at the bottom of the pressure relief channel 11, and is used for supporting and limiting the pressure relief rod 41 to prevent the pressure relief rod 41 from falling off from the pressure relief channel 11. A through hole is formed in the screw plug 45, and the free end of the push rod 43 passes through the through hole.

[0048] The first elastic member 44 is sleeved on the pressure relief rod 41 and located in the large-diameter section of the pressure relief channel 11. That is, the first elastic member 44 is limited between the step of the pressure relief channel 11 and the second protruding ring 412 on the pressure relief rod 41. The first elastic member 44 is preferably a return spring, which is used for returning the pressure relief rod 41 to the initial position after pressure relief.

[0049] The working principle of the over-travel automatic pressure relief stretcher of the embodiment is as follows:

[0050] When the high-pressure oil generated by the hydraulic pump enters the oil cavity between the cylinder body 1 and the piston 2 through the quick connector, the piston 2 is pushed to move upward, and the push rod 43 is synchronously moved upward through the center guide sleeve 3. Since there is a safety stroke distance between the free end of the push rod 43 and the pressure relief rod 41, the oil cavity is in a sealed state within the safety stroke of the stretcher, and the stretcher can work normally.

[0051] When the piston 2 continues to rise and starts to over-travel, the free end of the push rod 43 passes through the through hole in the screw plug 45 and starts to push the pressure relief rod 41 to move upward, and the first elastic member 44 is compressed. Since the sealing ring 42 is axially limited in the first limiting groove 12, the pressure relief groove 411 on the pressure relief rod 41 continuously approaches the position of the sealing ring 42. When the pressure relief groove 411 moves to the position of the sealing ring 42, a gap is formed between the two, the sealing state of the oil cavity is broken, and automatic pressure relief is performed.

[0052] After the pressure relief is completed, the piston 2 and the center guide sleeve 3 return to the initial state. At this time, the first elastic member 44 in the compressed state pushes the pressure relief rod 41 to the initial position to facilitate the over-travel pressure relief protection next time.

[0053] It should be noted that the stretcher in the embodiment also has an automatic reset function, and the specific automatic reset device can adopt the reset device of the prior art.

[0054] Embodiment 2

[0055] The over-travel automatic pressure relief stretcher of the embodiment is based on the embodiment 1, and the stretch nut 5 is optimally designed, so that the assembly between the stretch nut 5 and the bolt to be stretched is more convenient and fast.

[0056] Reference Figure 1 、 Figure 5As shown, the stretching nut 5 comprises a first half nut 51 and a second half nut 52 which can be locked and separated with each other. The inner arc side walls of the first half nut 51 and the second half nut 52 are provided with internal threads (not shown in the figure). When the two half nuts are close to each other and locked, the internal threads of the first half nut 51 and the second half nut 52 together form an internal thread which matches the external thread of the bolt to be stretched.

[0057] Specifically, the first half nut 51 and the second half nut 52 are connected by the connecting rod 6. The first half nut 51 is provided with a first mounting hole 53 through which the connecting rod 6 passes, and the second half nut 52 is provided with a second mounting hole 54 into which the connecting rod 6 is inserted.

[0058] One end of the connecting rod 6 passes through the first half nut 51 and extends into the second half nut 52 for connection. The first half nut 51 can slide back and forth along the connecting rod 6, and the first half nut 51 and the connecting rod 6 are locked or separated by the limiting piece 7.

[0059] One end of the connecting rod 6 is provided with a limiting part 61 which matches the first mounting hole 53, and the other end is provided with a connecting part 62 which matches the second mounting hole 54. The connecting rod 6 is also provided with a second limiting groove 63 which matches the limiting piece 7. The second limiting groove 63 is located near the limiting part 61.

[0060] In this embodiment, the first mounting hole 53 is a through hole, and the second mounting hole 54 is a blind hole. Both of them are stepped holes. The second limiting groove 63 is an annular groove, and an arc chamfer is provided between the annular groove and the outer peripheral wall of the connecting rod 6 to facilitate the sliding of the limiting piece 7 out of the second limiting groove 63.

[0061] During assembly, the connecting part 62 of the connecting rod 6 passes through the first mounting hole 53 and extends into the second mounting hole 54 to complete the connection between the connecting rod 6 and the second half nut 52. At this time, the limiting part 61 of the connecting rod 6 is located outside the first mounting hole 53, and the first half nut 51 and the second half nut 52 are ensured to have a certain moving space. Thus, the first half nut 51 and the second half nut 52 can be locked and separated while being connected by the connecting rod 6, and the phenomenon of falling off does not occur.

[0062] In this embodiment, the limiting part 61 comprises a limiting ring and a hexagonal nut. The limiting ring is used to stop the entire limiting part 61 outside the first mounting hole 53, and the hexagonal nut is used to facilitate the rotation of the connecting rod 6. The outer peripheral wall of the connecting part 62 is provided with external threads, and the end of the second mounting hole 54 is provided with internal threads (not shown in the figure). They are connected by threads.

[0063] In addition, the connecting rod 6 is sleeved with a second elastic member 64, which is limited between the stepped surfaces of the two mounting holes. The second elastic member 64 is arranged to make the first half nut 51 and the second half nut 52 have a damping feeling when assembled and a boosting feeling when disassembled. Preferably, the second elastic member 64 is a spring.

[0064] Reference Figure 7 As shown, the limiting member (7) includes a fixed sleeve (71), a third elastic member (72), and a steel ball (73), wherein the third elastic member (72) and the steel ball (73) are located in the fixed sleeve (71), and the third elastic member (72) is located between the top wall of the fixed sleeve (71) and the steel ball (73) to always provide elastic force to the steel ball 73. The steel ball 73 cooperates with the second limiting groove 63 to lock or separate the connecting rod 6. Preferably, the third elastic member 72 is also a spring.

[0065] The over-travel automatic pressure relief stretcher of the embodiment is assembled (the first half nut 51 and the second half nut 52 are in a separated state), the stretching nut 5 is sleeved on the bolt to be stretched; then, the stretching nut 5 is squeezed inward, so that the first half nut 51 drives the limiting member 7 to move along the outer peripheral wall of the connecting rod 6 to the direction of the second half nut 52; when the limiting member 7 moves to the second limiting groove 63, the steel ball 73 is clamped into the second limiting groove 63 under the elastic force of the third elastic member 72, and the locking operation between the first half nut 51 and the second half nut 52 is completed. When disassembled, opposite forces are applied to the first half nut 51 and the second half nut 52, and the steel ball 73 slides out of the second limiting groove 63 along the arc chamfer of the second limiting groove 63 under the action of the external force, that is, the separation work between the first half nut 51 and the second half nut 52 is completed. Finally, the stretching nut 5 is removed from the bolt.

[0066] Compared with the traditional stretcher, the stretching nut 5 needs to be rotated for many turns to complete the connection or disassembly of the nut and the bolt, and the axis between the two needs to be consistent during the rotation. The stretching nut 5 in the embodiment adopts a clamping type mounting mode, which greatly reduces the assembly time and improves the assembly efficiency. It is especially suitable for the disassembly operation of the bolt in special environments such as underwater.

[0067] The above description of the present application and its embodiments is illustrative and not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the present application, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, similar structural modes and embodiments can be designed without creativity, which should belong to the protection scope of the present application.

Claims

1. An overtravel automatic pressure relief stretcher comprising a cylinder (1) and a piston (2), said cylinder (1) and piston (2) defining an oil chamber therebetween, characterized in that: The piston (2) is connected with a center guide sleeve (3), the end of the center guide sleeve (3) extends into the hollow cavity of the cylinder body (1), and the center guide sleeve (3) is provided with a pressure relief assembly (4) between the cylinder body (1). The pressure relief assembly (4) comprises a pressure relief rod (41) in a pressure relief channel (11) and a sealing ring (42) sleeved on the pressure relief rod (41), wherein the pressure relief channel (11) is formed on the cylinder body (1) and communicates with the oil cavity; the pressure relief rod (41) is relatively displaced with the sealing ring (42) under the driving of the center guide sleeve (3), and a gap is formed between the sealing ring (42) and a pressure relief groove (411) on the pressure relief rod (41).

2. An overstroke self-relieving stretch wrapper according to claim 1, characterized in that: The bottom of the center guide sleeve (3) is provided with a first convex ring (31) arranged in the circumferential direction, and the first convex ring (31) is provided with a push rod (43) for pushing the pressure relief rod (41).

3. An overstroke self-relieving stretch wrapper according to claim 2, characterized in that: The pressure relief channel (11) is parallel to the central axis of the cylinder body (1) and is an upper small and lower large stepped through hole, and a first limiting groove (12) for accommodating the sealing ring (42) is formed on the small diameter section.

4. An overstroke self-relieving stretch wrapper according to claim 3, wherein: The pressure relief rod (41) is sleeved with a first elastic member (44), and the first elastic member (44) is limited between the stepped surface of the pressure relief channel (11) and a second convex ring (412) on the pressure relief rod (41).

5. An overstroke self-relieving stretch wrapper according to claim 4, characterized in that: The pressure relief channel (11) is provided with a screw plug (45), the screw plug (45) is located at the bottom of the pressure relief rod (41), and a through hole is formed in the screw plug (45) for the free end of the push rod (43) to pass through.

6. An overstroke self-relieving stretch wrapper according to any one of claims 1-5, characterized in that: The piston (2) is provided with a stretch nut (5), the stretch nut (5) comprises a first half nut (51) and a second half nut (52), and the two nuts are connected by a connecting rod (6); the connecting rod (6) is provided with a second limiting groove (63) matched with a limiting member (7) on the first half nut (51).

7. An overstroke self-relieving stretch wrapper according to claim 6, wherein: The first half nut (51) is provided with a first mounting hole (53) for the connecting rod (6) to pass through, and the second half nut (52) is provided with a second mounting hole (54) for the connecting rod (6) to insert.

8. An overstroke self-relieving stretch wrapper according to claim 7, characterized in that: One end of the connecting rod (6) is provided with a limiting portion (61) matched with the first mounting hole (53), and the other end is provided with a connecting portion (62) matched with the second mounting hole (54).

9. An overstroke self-relieving stretch wrapper according to claim 8, characterized in that: The connecting rod (6) is sleeved with a second elastic member (64), wherein the first mounting hole (53) and the second mounting hole (54) are both stepped holes, and the second elastic member (64) is limited between the stepped surfaces of the two stepped holes.

10. An overstroke self-relieving stretch wrapper according to claim 9, wherein: The limiting member (7) comprises a fixed sleeve (71), a third elastic member (72) and a steel ball (73), wherein the third elastic member (72) and the steel ball (73) are located in the fixed sleeve (71), and the third elastic member (72) is located between the top wall of the fixed sleeve (71) and the steel ball (73).

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