A cold drawn bolt stretcher

Abstract

The utility model relates to a cold drawn bolt stretcher, including frame, set up the stretching device and the detection device who sets up one side for detecting the displacement of cold drawn bolt end part of stretching device on the frame, the stretching device includes the support cylinder of sleeveing at the outside of cold drawn bolt, the first round nut of setting up one end in the support cylinder and with the screw joint of one end of cold drawn bolt, the stretching bolt of installing through the thread connection in the other end of cold drawn bolt and the stretcher assembly of installing on the stretching bolt, is equipped with the measuring hole along the axial direction of stretching bolt, the detection device stretches into the measuring hole, the utility model discloses the automatic stretching action of cold drawn bolt is realized through the stretching device, through the detection device detection cold drawn bolt end part's displacement, can realize the function of real -time on -line detection its elongation, has saved the step of the stretcher of cold drawn bolt after stretching dismounting simultaneously. Reduced the dismounting action of the stretcher of bolt after stretching, reduced the process of measuring bolt length before and after stretching.

Description

Technical Field

[0001] This utility model relates to a cold-drawn bolt stretching machine. Background Technology

[0002] Cold-drawn bolts are commonly used to connect and fasten the rotor couplings of steam turbines at all stages. To ensure the reliability of the bolt connection, cold-drawn bolts need to undergo a tensile test before leaving the factory to determine the rated elongation value of the batch of bolts and to check for the risk of hidden cracks. This is a verification method to ensure that the bolts can maintain a reliable connection under extreme load conditions.

[0003] Typically, users of cold-drawn bolts use manual tools (hydraulic tensioners) to stretch the bolts. When the manual pump stretches the bolt to the design pressure value, the nut is manually tightened, and then the hydraulic pump is depressurized. Because the hydraulic tensioner is installed at the end of the cold-drawn bolt, it obstructs the measurement of the bolt's total length after stretching. Therefore, it is necessary to completely disassemble the tensioner assembly, then use a micrometer of the appropriate size to measure the effective length of the bolt under tension, and calculate the difference between this and the length measured before stretching. This difference represents the actual elongation of the bolt.

[0004] The above-mentioned bolt tensile testing elongation process includes: 1 tensile tester installation, 1 manual tensile test, 1 tensile tester disassembly, 2 data measurement operations, and 1 data comparison and calculation operation, totaling 6 steps. The production and installation quantity of cold-drawn bolts in the same batch ranges from approximately 16 to 24 sets; therefore, multiple sets are usually randomly selected for tensile testing, and this process is repeated. The cold-drawn bolts used on turbine couplings typically weigh between 10 kg and 30 kg. The disassembly, assembly, and measurement processes require two people working together, resulting in high labor intensity and low efficiency. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a cold-drawn bolt stretching machine that can realize the automatic stretching of cold-drawn bolts.

[0006] The technical solution adopted in this utility model is: A cold-drawn bolt tensioning machine includes a frame, a tensioning device mounted on the frame, and a detection device mounted on one side of the tensioning device for detecting the displacement of the cold-drawn bolt end. The tensioning device includes a support cylinder sleeved on the outside of the cold-drawn bolt, a first round nut mounted on one end of the support cylinder and screwed to one end of the cold-drawn bolt, a tensioning bolt mounted on the other end of the cold-drawn bolt via a threaded connection, and a tensioner assembly mounted on the tensioning bolt. A measuring hole is provided along the axial direction of the tensioning bolt, and the detection device extends into the measuring hole.

[0007] Furthermore, a square hole is provided radially at the front end of the tension bolt, and a pressure plate is provided in the square hole. The side of the pressure plate is in contact with the side of the cold-drawn bolt, and the square hole is connected to the measuring hole. The detection device is used to detect the displacement of the pressure plate.

[0008] Furthermore, the detection device includes a detection frame, a detection rod mounted on the detection frame, and a sensor mounted at the end of the detection rod, with the detection rod extending into a measuring hole.

[0009] Furthermore, the width of the square hole is greater than the thickness of the pressure plate, a step is provided on the tension bolt, and a spring is provided between the step and the pressure plate.

[0010] Furthermore, a sliding frame is provided on the frame, and the tensioning device is fixedly mounted on the sliding frame; the sliding frame includes a fixed block, a sliding block mounted on the fixed block, a support frame mounted on the sliding block, and a locking screw for fixing the sliding block, and the support cylinder is fixedly mounted on the support frame.

[0011] Furthermore, keyways corresponding to the positions of the sliding block and the support frame are provided on both sides, and positioning keys are provided in the keyways. Guide rings are provided on the contact surfaces of the sliding block and the support frame.

[0012] Furthermore, a second round nut is provided on the outer side of the other end of the cold-drawn bolt, and the second round nut is engaged with the end of the support cylinder.

[0013] Furthermore, blind holes for tightening the nuts are provided on the outer side walls of both the first and second round nuts.

[0014] Furthermore, a support ring is provided between the tensioner assembly and the support cylinder.

[0015] The positive effects of this utility model are: This invention achieves automatic stretching of cold-drawn bolts through a stretching device. A detection device monitors the displacement at the bolt end, enabling real-time online monitoring of elongation. This eliminates the need to disassemble the stretching device after stretching, reducing the need for pre- and post-stretching bolt length measurements. It also reduces operator workload, lowers time costs, and improves operational efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the tensioning device of this utility model; Figure 3 This is a schematic diagram of the tension bolt structure of this utility model; Figure 4 This is a schematic diagram of the sliding frame structure of this utility model; Figure 5 This utility model Figure 4 A left-view diagram; Figure 6 This utility model Figure 4 A top-down view; Figure 7 This is a schematic diagram of the detection device of this utility model. Detailed Implementation

[0017] As attached Figure 1-7 As shown, this embodiment discloses a cold-drawn bolt stretching machine, including a frame 1, a stretching device 2 disposed on the frame 1, and a detection device 4 disposed on the frame 1 and located on one side of the stretching device 2.

[0018] As attached Figure 2 , 3 As shown, the tensioning device 2 includes a horizontally arranged support cylinder 201, a cold-drawn bolt 202 disposed in the support cylinder 201 through a tapered sleeve 209, a first round nut 211 and a second round nut 210 disposed at the left and right ends of the cold-drawn bolt 202, a tensioning bolt 208 installed on the small end face of the cold-drawn bolt 202 by a threaded connection, and a tensioner assembly 207 installed on the cold-drawn bolt 208 by a threaded connection.

[0019] The first round nut 211 and the second round nut 210 respectively mate with both ends of the support cylinder 201, and a support ring 206 is provided between the support cylinder 201 and the tensioner assembly 207, with the support ring 206 sleeved on the outside of the second round nut 210. Blind holes for rotational locking are provided on the outer surfaces of the first round nut 211 and the second round nut 210, allowing them to be locked into the support cylinder 201 using a lever 203. Of course, a through hole must be provided on the support ring 206 for the lever 203 to mate with the second round nut 210.

[0020] A measuring hole 2082 is provided at the axial position of the tension bolt 208, and the detection device extends into the measuring hole 2082. In one embodiment of this invention, the measuring hole 2082 can be a through-hole design, allowing the detection device to directly detect the end face of the cold-drawn bolt 202 (here, the end face refers to the outer surface of the threaded hole at the connection between the cold-drawn bolt 202 and the tension bolt 208). In another embodiment of this invention, a square hole 2081 is provided radially at the front end of the tension bolt 208, and the measuring hole 2082 communicates with the square hole 2081. A pressure plate 204 is provided within the square hole 2081, with both ends of the pressure plate 204 extending out of the square hole 2081. One side of the pressure plate 204 engages with the rightmost side of the cold-drawn bolt 202. At this time, the displacement of the pressure plate 204 is equal to the displacement of the cold-drawn bolt 202. The detection device detects the displacement of the pressure plate 204, which is equivalent to detecting the displacement of the end face of the cold-drawn bolt 202.

[0021] In another embodiment of this utility model, in order to make the pressure plate 204 detachable, the width of the square hole 2081 is greater than the thickness of the pressure plate 204. A step 2083 is provided at the front end of the tension bolt 208. A spring 205 is provided between the step 2083 and the pressure plate 204. The elastic force of the spring 205 keeps the pressure plate 204 in contact with the end face of the cold-drawn bolt 202, ensuring the detection accuracy.

[0022] Preferably, the pressure plate 204 is made of copper. Copper is an antimagnetic material. Due to its weak magnetic effect, it can improve the sensitivity of the sensor 402 and fundamentally eliminate measurement errors.

[0023] As attached Figure 7 As shown, the detection device includes a detection frame 405 fixedly mounted on the frame 1, a detection rod 401 horizontally mounted on the detection frame 405, and a sensor 402 mounted at the end of the detection rod 401. The detection rod 401 extends into the measurement hole 2082 for detection. Preferably, a wire hole 404 is provided in the detection rod 401, and a data cable 403 passes through the wire hole 404. One end of the data cable is connected to the sensor 402, and the other end is connected to a preamplifier. The eddy current measurement signal is transmitted to the preamplifier for processing through the data cable. After processing, the signal is output to the grating meter for signal display through the data cable. Preferably, the signal display accuracy is 0.01.

[0024] As attached Figure 1 , 4 As shown in Figure 6, a sliding frame 3 is provided on the frame 1, and the support cylinder 201 of the tensioning device 2 is fixedly installed on the sliding frame 3.

[0025] The sliding frame 3 includes a fixed block 301 fixedly mounted on the frame 1, a sliding block 302 slidably mounted on the fixed block 301, a support frame 305 mounted on the sliding block 302, and a locking screw 303 for fixing the sliding block 302. The support cylinder 201 is integrally welded to the support frame 305. The sliding block 302 and the fixed block 301 are slidably connected by corresponding dovetail grooves, and the position of the sliding block 302 can be fixed by the locking screw 303. After it slides to a suitable position, tightening the screw will achieve the axial locking function of the sliding block 302.

[0026] Keyways with corresponding positions are provided on both sides of the sliding block 302 and the support frame 305, and a positioning key 304 is provided in the keyway to prevent rotation. Furthermore, a guide ring 306 is provided on the contact surface between the sliding block and the support frame 305, located in the middle of the support frame 305. A matching annular groove is formed in the middle of the sliding block 302, thus eliminating the possibility of axial movement of the support cylinder 201. Through the dual action of the positioning key 304 and the guide ring 306, the positioning and fixing of the support cylinder 201 are achieved, thereby ensuring the absolute position of the internal cold-drawn bolt 202.

[0027] In use, the tensile device 2 is first installed, and the sliding block 302 drives the tensile device 2 to slide to its limit position away from the detection device 4. The detection rod 401 and sensor 402 are installed and aligned with the tensile device 2, ensuring that the detection rod 401 is concentric with the center hole of the tensile bolt 208. The sliding block 302 is then slid towards the detection device 4, maintaining the distance between the sensor 402 and the pressure plate 204 within 1-2 mm, and the locking screw 303 is used to lock it in place. The current detection position is reset to zero and recorded as the detection zero point. The hydraulic control system 5 is activated, injecting oil and pressurizing the tensile assembly 207, forcing the tensile bolt 208 and the threaded cold-drawn bolt 202 to extend to the right. Under the compression force of the spring 205, the pressure plate 204, adhering to the end face of the cold-drawn bolt 202, is forced to move to the right. The fixed sensor 402 detects the dynamic movement of the pressure plate 204 in real time and outputs the value through a grating meter. When the pressure gauge shows that the pressure value has reached the design requirement, the hydraulic control system 5 stops supplying oil to maintain pressure. Using the lever 203, turn the second round nut 210 clockwise to tighten it, and the hydraulic control system 5 will release pressure to 0 MPa. At this point, the value detected by the sensor 402 is the final bolt elongation value.

[0028] This utility model discloses a novel tensile testing platform for cold-drawn bolts, which is a testing device integrating a cold-drawn bolt tensile testing device, a sliding device, a measuring system, and a display system. It is suitable for analyzing and inspecting the dynamic elongation values ​​of cold-drawn bolts and similar structural bolts, as well as the positive correlation coefficient between elongation values ​​and hydraulic pressure.

[0029] This invention uses a tensioner assembly to drive a cold-drawn bolt to perform a stretching operation. By relying on sensors to monitor the stretching changes in real time, it achieves dynamic monitoring during the stretching process and solves the problem of traditional methods being unable to monitor the process.

[0030] Compared to existing technologies, this new method changes the previous method of calculating the difference between two measurements before and after stretching to real-time detection, and eliminates the need to disassemble the tensioner, effectively reducing labor intensity and working hours. Furthermore, the traditional method of applying pressure directly to the tensioner components using a manual pump has been replaced with electric drive control, making it more integrated and intelligent.

[0031] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A cold-drawn bolt stretching machine, characterized in that... It includes a frame (1), a tensioning device (2) mounted on the frame (1), and a detection device (4) mounted on one side of the tensioning device (2) for detecting the displacement of the end of the cold-drawn bolt (202). The tensioning device (2) includes a support cylinder (201) sleeved on the outside of the cold-drawn bolt (202), a first round nut (211) mounted on one end of the support cylinder (201) and screwed to one end of the cold-drawn bolt (202), a tensioning bolt (208) mounted on the other end of the cold-drawn bolt (202) by a threaded connection, and a tensioner assembly (207) mounted on the tensioning bolt (208). A measuring hole (2082) is provided along the axial direction of the tensioning bolt (208), and the detection device (4) extends into the measuring hole (2082).

2. The cold-drawn bolt stretching machine according to claim 1, characterized in that... A square hole (2081) is provided radially at the front end of the tension bolt (208), and a pressure plate (204) is provided in the square hole (2081). The side of the pressure plate (204) is in contact with the side of the cold-drawn bolt (202). The square hole (2081) is connected to the measuring hole (2082). The detection device (4) is used to detect the displacement of the pressure plate (204).

3. A cold-drawn bolt stretching machine according to claim 1 or 2, characterized in that... The detection device (4) includes a detection frame (405), a detection rod (401) set on the detection frame (405), and a sensor (402) set at the end of the detection rod (401). The detection rod (401) extends into the measurement hole (2082).

4. A cold-drawn bolt stretching machine according to claim 2, characterized in that... The width of the square hole (2081) is greater than the thickness of the pressure plate (204). A step (2083) is provided on the tension bolt (208), and a spring (205) is provided between the step (2083) and the pressure plate (204).

5. A cold-drawn bolt stretching machine according to claim 1, characterized in that... A sliding frame (3) is provided on the frame (1), and a tensioning device (2) is fixedly installed on the sliding frame (3); The sliding frame (3) includes a fixed block (301), a sliding block (302) disposed on the fixed block (301), a support frame (305) disposed on the sliding block (302), and a locking screw (303) for fixing the sliding block (302). The support cylinder (201) is fixedly disposed on the support frame (305).

6. A cold-drawn bolt stretching machine according to claim 5, characterized in that... Keyways with corresponding positions are provided on both sides of the sliding block (302) and the support frame (305), and positioning keys (304) are provided in the keyways. Guide rings (306) are provided on the contact surfaces of the sliding block (302) and the support frame (305).

7. A cold-drawn bolt stretching machine according to claim 1, characterized in that... A second round nut (210) is provided on the outer side of the other end of the cold-drawn bolt (202), and the second round nut (210) is engaged with the end of the support cylinder (201).

8. A cold-drawn bolt stretching machine according to claim 7, characterized in that... Both the first round nut (211) and the second round nut (210) have blind holes on their outer side walls for tightening the nuts.

9. A cold-drawn bolt stretching machine according to claim 1, characterized in that... A support ring (206) is provided between the tensioner assembly (207) and the support cylinder (201).

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