A bolt tensioner with stroke pressure protection

Abstract

This utility model discloses a bolt tensioner with stroke pressure protection, including a central column, a locking nut sleeved on the top of the central column, a piston connected to the bottom of the locking nut, a hydraulic cylinder sleeved on the outside of the piston, a washer connected to the bottom of the hydraulic cylinder, and a piston limiting rod disposed inside the hydraulic cylinder. A piston limiter assembly is disposed inside the washer. In this utility model, by setting the piston limiter assembly inside the washer and communicating with the oil port of the washer, the openness or closedness of the oil port on the washer is determined by the passage within the piston limiter assembly. The cylindrical pin is in a resisting state with the piston limiting rod, so that once the tension reaches its limit, the piston limiting rod moves to its limit, causing the cylindrical pin to be springed upwards by a spring, thereby sealing the oil port on the washer with a steel ball. This prevents oil from entering, thus achieving protection and improving the safety of the device.

Description

Technical Field

[0001] This utility model relates to the field of bolt tensioner technology, specifically a bolt tensioner with stroke pressure protection. Background Technology

[0002] A bolt tensioner, also known as a hydraulic bolt tensioner, utilizes a hydraulic booster pump (ultra-high pressure hydraulic pump) to provide a hydraulic source. The tension force is determined based on the material's tensile strength, yield coefficient, and elongation. The tension generated by the ultra-high pressure pump causes the bolt to be stretched within its elastic deformation zone, resulting in slight bolt diameter deformation and making the nut easier to loosen. It can also be used as a device to apply axial force to hydraulic interference connections for pressurized installation. However, continuous oil supply is required during use. While the tensioner has limits, the oil supply has no limits. Without restriction, over-travel will occur, leading to device damage. Therefore, a bolt tensioner with stroke pressure protection is proposed. Utility Model Content

[0003] This utility model aims to solve one of the technical problems existing in the prior art or related technologies.

[0004] Therefore, the technical solution adopted by this utility model is as follows:

[0005] A bolt tensioner with stroke pressure protection includes a central column, a locking nut fitted to the top of the central column, a piston connected to the bottom of the locking nut, a hydraulic cylinder fitted to the outside of the piston, a washer connected to the bottom end of the hydraulic cylinder, a piston limiting rod disposed inside the hydraulic cylinder, a piston limiter assembly disposed inside the washer, the bottom end of the piston limiting rod abutting against the top end of the piston limiter assembly, and the piston limiter assembly including a housing fixed inside the washer, a cylindrical pin inserted into the middle of the housing, a steel ball slidably connected to the bottom of the housing and located below the cylindrical pin, a fixed seat connected to the bottom of the steel ball, a spring disposed at the bottom of the fixed seat for providing elastic force, and a screw plug assembled at the bottom end of the housing.

[0006] Preferably, a retaining ring one, an O-ring one, an O-ring two, and a retaining ring two are provided at the position where the piston contacts the oil cylinder. The retaining ring one is installed on the piston, and the retaining ring two is installed on the oil cylinder.

[0007] Preferably, a gasket and a retaining ring for the hole located below the gasket are provided at the bottom of the piston limiting rod position of the hydraulic cylinder.

[0008] Preferably, a sealing ring is installed on the piston limiter assembly at the position where it is exposed and the gasket ring is located.

[0009] Preferably, the side of the hydraulic cylinder is threaded with an internal hexagonal head bolt, and the bottom end of the internal hexagonal head bolt passes through the hydraulic cylinder and is threadedly connected to the gasket.

[0010] Preferably, an O-ring is fitted onto the side of the top of the housing.

[0011] By adopting the above technical solution, the beneficial effects achieved by this utility model are as follows:

[0012] In this invention, by setting a piston limiter assembly inside the gasket and communicating with the oil port of the gasket, the passage inside the piston limiter assembly determines the opening and closing of the oil port on the gasket. The cylindrical pin is in a resisting state with the piston limiter rod, so that once it is stretched to the limit, the piston limiter rod moves to its limit, causing the cylindrical pin to be springed upward by the spring, thereby causing the steel ball to seal the oil port on the gasket. At this time, oil cannot enter, thus achieving protection and improving the safety of the device. Attached Figure Description

[0013] Figure 1 This is a cross-sectional schematic diagram of one embodiment of the present utility model;

[0014] Figure 2 This is a cross-sectional schematic diagram of a piston limiter assembly according to an embodiment of the present invention.

[0015] Figure label:

[0016] 1. Locking nut; 2. Piston; 3. Hydraulic cylinder; 4. Retaining ring 1; 5. O-ring 1; 6. O-ring 2; 7. Retaining ring 2; 8. Piston limiting rod; 9. Gasket; 10. Hole retaining ring; 11. Sealing ring;

[0017] 12. Piston limiter assembly; 121. Housing; 122. O-ring three; 123. Cylindrical pin; 124. Steel ball; 125. Fixing seat; 126. Spring; 127. Plug;

[0018] 13. Washer ring; 14. Socket head cap screw. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features of the present utility model can be combined with each other.

[0020] The following describes, with reference to the accompanying drawings, some embodiments of the present invention, providing a bolt tensioner with stroke pressure protection.

[0021] Example:

[0022] Combination Figure 1-2As shown, this utility model provides a bolt tensioner with stroke pressure protection, including a central column, a locking nut 1 sleeved on the top of the central column, a piston 2 connected to the bottom of the locking nut 1, and a hydraulic cylinder 3 sleeved on the outside of the piston 2. A retaining ring 4, an O-ring 5, an O-ring 6, and a retaining ring 7 are provided at the contact position between the piston 2 and the hydraulic cylinder 3. The retaining ring 4 is installed on the piston 2, and the retaining ring 7 is installed on the hydraulic cylinder 3. A washer 13 is connected to the bottom of the hydraulic cylinder 3, and a piston limiting rod 8 is provided inside the hydraulic cylinder 3. A washer 9 and a retaining ring 10 with a hole below the washer 9 are provided at the bottom of the hydraulic cylinder 3 where it inserts into the piston limiting rod 8. A hexagonal head bolt 14 is threadedly connected to the side of the hydraulic cylinder 3, and the bottom end of the hexagonal head bolt 14 passes through... The cylinder 3 is threadedly connected to the washer ring 13. The piston limiter assembly 12 is provided inside the washer ring 13. The bottom end of the piston limiter rod 8 abuts against the top end of the piston limiter assembly 12. A sealing ring 11 is installed on the piston limiter assembly 12 at the position where it is exposed to the washer ring 13. The piston limiter assembly 12 includes a housing 121 fixed inside the washer ring 13, a cylindrical pin 123 inserted into the middle of the housing 121, a steel ball 124 slidably connected to the bottom of the housing 121 and located below the cylindrical pin 123, a fixing seat 125 connected to the bottom of the steel ball 124, a spring 126 provided at the bottom of the fixing seat 125 to provide elastic force, and a screw plug 127 assembled at the bottom end of the housing 121. An O-ring 122 is sleeved on the side of the top of the housing 121.

[0023] Specifically, when the stroke of the cylindrical pin 123 has not reached its limit, that is, when the stroke of the tensioner has not reached its limit, oil can be supplied normally. When the stroke reaches its limit, that is, when the steel ball 124 is pushed upward by the spring 126 until the oil port of the sealing washer 13 is closed, the oil supply stops. It is efficient, safe and requires no power.

[0024] Working principle and usage process of this utility model:

[0025] In the initial state, when piston 2 is at the bottom of cylinder 3, the stroke is zero and the spring 126 inside piston limiter assembly 12 is in a compressed state. At this time, the internal oil circuit is connected and hydraulic oil can be injected into the oil chamber of cylinder 3 and piston 2 through the oil port on the gasket ring 13 to perform oil injection.

[0026] When the piston 2 reaches its maximum stroke, the stroke is 30mm. At this time, under the action of the spring 126, the steel ball 124 moves upward with the cylindrical pin 123 and the piston limit rod 8. After reaching the maximum stroke, the steel ball 124 contacts the orifice of the housing 121. Under the action of oil pressure, the steel ball 124 and the orifice of the housing 121 are in complete contact, achieving a sealing effect. At this time, hydraulic oil cannot be injected into the oil chamber of the cylinder 3 and the piston 2 from the oil port on the gasket 13. Without oil entering the upper cylinder, the upper piston 2 cannot generate a larger amount of movement, thus achieving the stroke protection function.

[0027] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A bolt tensioner with travel pressure protection comprising a center column, characterized in that, A locking nut (1) is fitted onto the top of the central column, and a piston (2) is connected to the bottom of the locking nut (1). A hydraulic cylinder (3) is fitted onto the outside of the piston (2). A washer (13) is connected to the bottom end of the hydraulic cylinder (3), and a piston limiting rod (8) is provided inside the hydraulic cylinder (3). A piston limiter assembly (12) is provided inside the washer (13), and the bottom end of the piston limiting rod (8) abuts against the top end of the piston limiter assembly (12). The piston limiter assembly (12) includes a housing (121) fixed inside the washer ring (13), a cylindrical pin (123) inserted into the middle of the housing (121), a steel ball (124) slidably connected to the bottom of the housing (121) and located below the cylindrical pin (123), a fixing seat (125) connected to the bottom of the steel ball (124), a spring (126) provided at the bottom of the fixing seat (125) for providing elastic force, and a screw plug (127) assembled at the bottom of the housing (121).

2. A bolt tensioner with stroke pressure protection according to claim 1, characterized in that, The piston (2) is provided with a retaining ring one (4), an O-ring one (5), an O-ring two (6), and a retaining ring two (7) at the contact position with the oil cylinder (3). The retaining ring one (4) is installed on the piston (2), and the retaining ring two (7) is installed on the oil cylinder (3).

3. A bolt tensioner with stroke pressure protection according to claim 1, characterized in that, The bottom of the position where the oil cylinder (3) is inserted into the piston limiting rod (8) is provided with a gasket (9) and a retaining ring (10) for the hole located below the gasket (9).

4. A bolt tensioner with stroke pressure protection according to claim 1, characterized in that, A sealing ring (11) is installed on the piston limiter assembly (12) at the position of the gasket (13).

5. A bolt tensioner with stroke pressure protection according to claim 1, characterized in that, The side of the oil cylinder (3) is threaded with an internal hexagonal head bolt (14), and the bottom end of the internal hexagonal head bolt (14) passes through the oil cylinder (3) and is threadedly connected to the washer (13).

6. A bolt tensioner with stroke pressure protection according to claim 1, characterized in that, The top side of the housing (121) is fitted with an O-ring three (122).

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