Universal clamp for positioning and clamping thick and short shafts

Abstract

The invention discloses a universal clamp for positioning and clamping a stub shaft, comprising two groups of upper covers and lower V-shaped seats for clamping the two ends of the stub shaft respectively, and a wire rope clamping device, wherein one end of the wire rope of the wire rope clamping device is hooked in the upper part of the hook base, and the other end passes through one side of the upper part of the lower V-shaped seat upwards, bypasses the semicircular groove on the outer side of the upper cover, and then passes through the other side of the upper part of the lower V-shaped seat downwards and is fixed on the outer circumferential surface of the wire rope drum. The two ends of the drum shaft supporting the wire rope drum are respectively supported on the middle part of the corresponding drum support, and the bottom of the drum support is respectively fixed on the other end of the lower part of the lower V-shaped seat. The ratchet pawl mechanism is arranged between the inner side of the drum support and the end face of one end of the wire rope drum, and one end of the drum shaft is fixedly connected to a circular plate equipped with a rotating handle. The invention can reliably position and clamp the stub shaft, and can complete the positioning and clamping of the stub shaft in just a few minutes, and the loading is uniform, which significantly improves the efficiency of positioning and clamping the stub shaft.

Description

Technical Field

[0001] The invention relates to a tool for positioning and clamping shaft parts, in particular to a fixture for positioning and clamping thick and short shafts with a diameter of more than 300 mm and a length-to-diameter ratio of less than 5, belonging to the technical field of metal cutting processing. Background Art

[0002] The stub shaft needs to be positioned and clamped with a special fixture before it can be used for CNC boring and milling machine processing. The existing stub shaft positioning and clamping fixture adopts a structural type in which two upper and lower V-shaped components clamp the two ends of the stub shaft respectively, and then the fixture that clamps the stub shaft is fixed horizontally on the workbench of the CNC boring and milling machine. The shape and position tolerance of the stub shaft is measured by the movement of the spindle of the CNC boring and milling machine, and the workpiece is fine-tuned to determine whether its parallelism and verticality meet the process requirements. Figure 1 The figure shows a stub shaft positioning and clamping tool, in which the stub shaft 100 is clamped and positioned by the upper V-shaped pressure plate 10 and the lower V-shaped block 20. The lower end of the screw rod 30 passes through the notches 101 at both ends of the upper V-shaped pressure plate 10 from top to bottom, and is screwed into the two ends of the lower V-shaped block 20. The upper ends of the screw rod 30 are screwed with clamping nuts 40 to clamp the two ends of the upper V-shaped pressure plate 10, thereby completing the restriction of its vertical freedom.

[0003] The following shortcomings were found in this tooling:

[0004] 1. The upper V-shaped pressing plate 10, the lower V-shaped block 20 and the outer circumferential surface of the thick short shaft 100 are in line contact, which affects the positioning and pressing effect of the thick short shaft 100.

[0005] 2. Since the clamping nuts 40 at both ends of the upper V-shaped pressure plate 10 need to be tightened at the same time, and it is difficult to ensure that the clamping force at both ends of the upper V-shaped pressure plate 10 is the same by manual tightening, the unequal clamping force makes it difficult for the upper V-shaped pressure plate 10 to be in a horizontal state, and the force point of the thick short shaft will also change. The clamping force no longer acts on the workpiece in a vertical direction, affecting the processing accuracy.

[0006] 3. The installation of the fixture is complicated. Workers need to tighten the four clamping nuts 40 at both ends of the two upper V-shaped pressure plates 10. During installation, the clamping nuts 40 are first slightly tightened, and then the four clamping nuts 40 are tightened alternately and gradually in a diagonal tightening manner. A wrench and a force rod are required for tightening. The entire installation process takes 10 to 20 minutes, and the work efficiency is very low. Summary of the invention

[0007] The purpose of the present invention is to provide a universal clamp for positioning and clamping a thick short shaft, which can quickly position and clamp and has uniform clamping force.

[0008] The present invention is achieved through the following technical solutions:

[0009] A universal clamp for positioning and clamping a thick and short shaft, comprising two groups of upper covers and lower V-shaped seats for clamping the two ends of the thick and short shaft respectively, and wire rope clamping devices respectively arranged on both sides of each group of upper covers and lower V-shaped seats, wherein the upper cover is semicircular, and the semicircular arc on the inner side of the upper cover matches the outer circle of the thick and short shaft; a V-shaped notch for supporting the thick and short shaft is provided on the upper part of the lower V-shaped seat, and the thick and short shaft is positioned in the V-shaped notch of the lower V-shaped seat and fixed to the upper side of the semicircular copper-clad thick and short shaft on the inner side of the upper cover; the wire rope clamping device comprises a wire rope, a hook base, a hook, a wire rope drum, a drum shaft, a pair of drum supports, a circular plate, a rotating handle and a ratchet pawl mechanism, the bottom of the hook base is fixed on one end of the lower part of the lower V-shaped seat, and ... One end of the wire rope is fixedly connected to one end of the hook, and the other end of the hook is hooked in the upper part of the hook base. The other end of the wire rope passes upward through the side groove on one side of the upper part of the lower V-shaped seat and then bypasses the semicircular groove on the outer side of the upper cover, and then passes downward through the side groove on the other side of the upper part of the lower V-shaped seat and is fixed on the outer circumferential surface of the wire rope drum; the middle part of the drum shaft is fixedly connected to both ends of the wire rope drum, and the two ends of the drum shaft are respectively supported on the middle part of the corresponding drum support through bearings, and the bottom of the drum support is respectively fixed on the other end of the lower part of the lower V-shaped seat; the ratchet pawl mechanism is arranged between the inner side of the drum support and the end face of one end of the wire rope drum, one end of the drum shaft extends out of the drum support and is fixedly connected to the vertically arranged circular plate, and one end of the horizontally arranged rotating handle is fixed on the outer edge of the circular plate.

[0010] The purpose of the present invention can be further achieved by the following technical measures.

[0011] Furthermore, the drum support is in an inverted T-shape, the wire rope drum is embedded between the two drum supports, the ratchet pawl mechanism is arranged between the inner side of the upper part of one drum support and one end of the wire rope drum, and the other end of the wire rope drum rests on the inner side surface of the upper part of the other drum support; the ends of the drum shaft are axially limited by limiting plates respectively.

[0012] Furthermore, the ratchet pawl mechanism includes a ratchet, a pawl, a pawl pin, a tension spring and two tension spring pins. The ratchet is fixed to the drum shaft at one end of the wire rope drum through a ratchet flat key and is adjacent to the inner side surface of the upper part of a drum support. The pawl is located on the upper side of the ratchet. One end of the pawl pin crosses the upper part of a drum support and is fixedly connected to the upper part of the drum support. The other end of the pawl pin is supported on the middle part of the pawl through a pawl pin sleeve. The middle part of the pawl is hinged to the upper part of the drum support through the pawl pin. One end of the pawl is embedded in the tooth groove of the ratchet. One tension spring pin is fixed to the upper inner part of the corresponding drum support, and the other tension spring pin is fixed to the other end of the pawl. The two ends of the tension spring are respectively hooked on the corresponding tension spring pin. The other end of the pawl extends outward to form a wrench handle.

[0013] Furthermore, the ratio of the semicircular groove width A to the wire rope diameter d is A / d, and the ratio of the side groove width B to the wire rope diameter d is B / d, both of which are 2.3 to 2.7. The ratio of the semicircular groove depth C to the wire rope diameter d is C / d=1.1 to 1.5, and the ratio of the side groove depth H to the wire rope diameter d is H / d=2.2 to 2.6.

[0014] The tightened wire rope of the present invention clamps the stub shaft through the upper cover, and the loading is fast and uniform, thereby improving the positioning and clamping accuracy of the workpiece. The ratchet pawl mechanism prevents the wire rope drum from reversing and loosening the wire rope, thereby ensuring that the upper cover and the lower V-shaped seat always remain in a state of clamping the stub shaft. The present invention changes the line contact between the inner side of the two inclined surfaces of the inverted V-shape of the upper cover of the prior art and the upper side of the stub shaft into a surface contact between the inner side of the semicircular arc of the upper cover and the upper side of the stub shaft, which significantly increases the clamping force of the present invention on the stub shaft. The positioning and clamping of the stub shaft can be completed in just a few minutes, which significantly improves the positioning and clamping efficiency of the present invention on the stub shaft. By replacing upper covers with different curvatures, it can be used for the positioning and clamping of stub shafts of different diameters, and has good versatility.

[0015] Advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments thereof, which are given by way of example only with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the structural diagram of the existing fixture;

[0017] Figure 2 It is a structural diagram of the present invention;

[0018] Figure 3 yes Figure 2 Right view of;

[0019] Figure 4 yes Figure 2 Enlarged view of part I. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and an embodiment of a crosshead pin of a certain type of marine low-speed diesel engine.

[0021] The cross pin is a key part among the three moving parts of a marine low-speed diesel engine. It is used to connect the connecting rod and the piston rod, and its technical difficulty and processing precision are extremely high. For example, the finished cross pin of a certain type of marine low-speed diesel engine has an outer diameter of 450mm, a length of 878mm, and a single piece net weight of 1392kg, which is a typical thick short shaft.

[0022] The dimensional tolerance of its outer circle is upper deviation -0.068, lower deviation -0.088, roughness is Ra1.6, and there are a series of form and position tolerances with strict precision requirements.

[0023] In the description of the present invention, terms indicating orientation or positional relationship such as “center”, “up”, “down”, “left”, “right”, “inside” and “outside” are based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the device referred to must have a specific orientation.

[0024] like Figure 2 As shown, this embodiment includes two groups of upper covers 1 and lower V-shaped seats 2 for clamping the two ends of the thick short shaft 100 respectively, and wire rope clamping devices 3 respectively arranged on both sides of each group of upper covers 1 and lower V-shaped seats 2. The upper cover 1 is semicircular, and the semicircular arc inside the upper cover 1 matches the outer circle of the thick short shaft 100. A pair of lifting rings 11 are symmetrically arranged on the outer arc surface of the upper cover 1. A V-shaped notch 21 for supporting the thick short shaft 100 is provided on the upper part of the lower V-shaped seat 2. The thick short shaft 100 is positioned in the V-shaped notch 21 of the lower V-shaped seat. The semicircular copper sheet 12 fixed on the inner side of the upper cover 1 covers the upper side of the thick short shaft 100 to prevent the upper cover 1 from damaging the outer circle of the thick short shaft 100.

[0025] like Figure 2 and Figure 3 As shown, the wire rope clamping device 3 includes a wire rope 31, a hook base 32, a hook 33, a wire rope drum 34, a drum shaft 35, a pair of drum supports 36, a circular plate 37, a rotating handle 38 and a ratchet pawl mechanism 39. The bottom of the hook base 32 is fixed by a fastening screw as shown in FIG. Figure 2 On the lower left end of the lower V-shaped seat 2 shown, one end of the wire rope 31 is fixedly connected to one end of the hook 33, and the other end of the hook 33 is hooked in the upper part of the hook base 32. The other end of the wire rope 31 passes upward through the side groove 22 on the left side of the upper part of the lower V-shaped seat 2, bypasses the semicircular groove 13 on the outer side of the upper cover 1, and then passes downward through the side groove 22 on the right side of the upper part of the lower V-shaped seat 2 and is fixed on the outer circumferential surface of the wire rope drum 34. The middle part of the drum shaft 35 is fixedly connected to the two ends of the wire rope drum 34 through the drum flat key 341, and the two ends of the drum shaft 35 are supported on the middle part of the corresponding drum support 36 through the bearing 351. The bottom of the drum support 36 is fixed to the lower right end of the lower V-shaped seat 2 through the fastening screws.

[0026] The drum support 36 is in an inverted T shape, the wire rope drum 34 is embedded between the two drum supports 36, the ratchet pawl mechanism 39 is arranged between the upper right side of one drum support 36 and the left end of the wire rope drum 34, and the right end of the wire rope drum 34 abuts against the upper left side surface of the other drum support 36. The ends of the drum shaft 35 are axially limited by the limit plates 352 respectively to prevent the drum shaft 35 from axially moving.

[0027] like Figure 3 and Figure 4As shown, the ratchet pawl mechanism 39 includes a ratchet 391, a pawl 392, a pawl pin 393, a tension spring 394 and two tension spring pins 395. The ratchet pawl mechanism 39 is arranged between the right side of the drum support 36 and the left end face of the wire rope drum 34. The right end of the drum shaft 35 extends out of the right side of the drum support 36 and is fixedly connected to the vertically arranged circular plate 37. The left end of the horizontally arranged rotating handle 38 is fixed to the outer edge of the circular plate 37. By grasping the rotating handle 38 and rotating it forward around the center of the drum shaft 35, the wire rope drum 34 can be driven to rotate forward to tighten the wire rope 31, so that the upper cover 1 and the lower V-shaped seat 2 can quickly position and clamp the thick short shaft 100.

[0028] The ratchet 391 is fixed to the left end of the wire rope drum 34 by a ratchet flat key 396 and is adjacent to the upper inner side surface of a drum support 36. The pawl 392 is located on the upper side of the ratchet 391. Figure 3 The left end of the middle pawl pin 393 crosses the upper part of a reel support 36 and is fixedly connected to the upper part of the reel support 36 by tightening the nut 398. The right end of the pawl pin 393 is supported on the middle part of the pawl 392 through the pawl pin sleeve 397. The middle part of the pawl 392 is hinged to the upper part of the reel support 36 through the pawl pin 393, and the left end of the pawl is embedded in the tooth groove 3911 of the ratchet wheel 391. A tension spring pin 395 is fixed to the upper inner part of the corresponding reel support 36, and another tension spring pin 395 is fixed to the right end of the pawl 392. The two ends of the tension spring 394 are respectively hooked on the corresponding tension spring pin 395. The restoring elastic force of the tension spring 394 ensures Figure 4 The left end of the ratchet 392 is embedded in the tooth groove 3911 of the ratchet wheel 391, so that the wire rope 31 is always kept in a tensioned state, ensuring that the thick short shaft 100 is always kept in a clamped state. The right end of the ratchet 392 extends outward to form a lever handle 3921, and when it is necessary to reversely rotate the wire rope drum 34 to loosen the wire rope 31 and remove the thick short shaft 100, Figure 4 As shown, by pressing the lever handle 3921 at the right end of the pawl 392, the pawl 392 overcomes the tension of the tension spring 394 and rotates clockwise around the center of the pawl pin 393, and the left end of the pawl 392 disengages from the tooth groove 3911 of the ratchet wheel 391, and the rotating handle 38 can be grasped to rotate the circular plate 37 in the opposite direction to loosen the wire rope 31, and the thick short shaft 100 is unloaded.

[0029] In this embodiment, the ratio A / d of the semicircular groove width A to the wire rope diameter d and the ratio B / d of the side groove width B to the wire rope diameter d are both 2.5, which can effectively prevent the wire rope 31 from rubbing against the side wall of the semicircular groove 11 or the side wall of the side groove 22 when the wire rope 31 is retracted or released. The ratio C / d of the semicircular groove depth C to the wire rope diameter d is 1.3, which can prevent the wire rope 31 from escaping from the semicircular groove 11. The ratio H of the side groove depth H to the wire rope diameter d is 2.4, which can prevent the wire rope 31 from rubbing against the bottom of the side groove 22, extend the service life of the wire rope 31, and reduce the rotation resistance of the rotating handle 38 around the center of the drum shaft 35.

[0030] Taking the assembly of a set of upper cover 1, lower V-shaped seat 2 and wire rope clamping devices 3 on both sides as an example, the assembly process of the present invention is as follows:

[0031] 1) Install the bearing 351 into the upper part of a reel support 36, and then install the pawl pin 393 and a tension spring pin 395 of the ratchet pawl mechanism 39 on the upper part of the inner side of a reel support 36, and install the pawl pin sleeve 397 on the middle part of the pawl 392, and install another tension spring pin 395 on the pawl 392. Then install the pawl pin sleeve 397 in the middle part of the pawl 392 on one end of the pawl pin 393, and then hook the two ends of the tension spring 394 on the corresponding tension spring pin 395 respectively.

[0032] 2) Pass the drum shaft 35 through the wire rope drum 34, so that the middle of the drum shaft 35 is fixedly connected to the two ends of the wire rope drum 34 through the drum flat key 341, and the two ends of the drum shaft 35 extend out of the wire rope drum 34. Then fix the ratchet 391 on the drum shaft 35 extending out of the left end of the wire rope drum 34 through the ratchet flat key 396.

[0033] 3) Install the two ends of the reel shaft 35 into the bearings 351 of one reel support 36 and the other reel support 36 respectively, and insert one end of the reel pawl 392 into the tooth groove 3911 of the ratchet wheel 391. Then fix the circular plate 37 with the rotating handle 38 to the right end of the reel shaft 35 through the circular plate flat key 371, and then fix the limit plate 352 to the two end heads of the reel shaft 35 respectively through the fastening screws.

[0034] 4) Fix the bottom of the hook base 32 with the screws. Figure 2 On the lower left end of the lower V-shaped seat 2 shown, the assembled two drum supports 36, drum shaft 35, wire rope drum 34 and ratchet pawl mechanism 39 are fixed on the right end of the lower V-shaped seat 2, the hook 33 at one end of the wire rope 31 is hooked in the upper part of the hook base 32, and the other end of the wire rope 31 passes through the side grooves 22 on both sides of the upper part of the lower V-shaped seat 2 and is fixed on the outer circumferential surface of the wire rope drum 34, thereby completing a set of lower V-shaped seat 2 and the assembly of the wire rope clamping device 3 on both sides.

[0035] The process of using the present invention to position and clamp the cross pin as the thick short shaft 100 is as follows:

[0036] 1) According to the length of the cross pin, determine the distance between the two sets of lower V-shaped seats 2 and the wire rope clamping device 3 components on both sides, and then fix the two sets of lower V-shaped seats 2 and the wire rope clamping device 3 components on the workbench 200 of the CNC boring and milling machine according to this distance.

[0037] 2) Lift the cross pin onto the two groups of lower V-shaped seats 2, so that the lower sides of the two ends of the cross pin are supported on the corresponding V-shaped notches 21 of the lower V-shaped seats 2, and then lift the upper cover 1 onto the two ends of the cross pin 200, so that the semicircular copper sheet 12 on the inner side of the upper cover 1 is respectively covered on the upper side of the corresponding ends of the thick short shaft 100, and the semicircular groove 13 on the outer side of the upper cover 1 is aligned with the side grooves 22 on both sides of the upper part of the lower V-shaped seat 2. Then, first hook the hook 33 at one end of the wire rope 31 on the upper part of the hook base 32, and then pass the wire rope 31 around the side groove 22 on the left side of the upper part of the lower V-shaped seat 2, the semicircular groove 13 on the outer side of the upper cover 1, and the side groove 22 on the right side of the upper part of the lower V-shaped seat 2 in sequence.

[0038] 3) Hold the handle 38 and rotate the circular plate 37 forward, driving the wire rope drum 34 to rotate forward to tighten the wire rope 31, so that the upper cover 1 and the lower V-shaped seat 2 can initially clamp and position the thick short shaft 100. At this time, one end of the pawl 392 is embedded in the tooth groove 3911 of the ratchet wheel 391 to lock the wire rope drum 34, so that the wire rope 31 remains in a tensioned state, and the cross pin is clamped by the upper cover 1 and the lower V-shaped seat 2. Then check the position tolerance of the cross pin and the spindle of the CNC boring and milling machine, and fine-tune the position of the cross pin to meet the position tolerance requirements. Rotate the circular plate 37 forward again to finally complete the positioning and clamping of the cross pin.

[0039] 4) After the cross pin is marked or processed, Figure 4 As shown, the lever handle 3921 at the right end of the pawl 392 is pressed, and the pawl 392 overcomes the tension of the tension spring 394 and rotates clockwise around the center of the pawl pin 393, and the left end of the pawl 392 is disengaged from the tooth groove 3911 of the ratchet wheel 391, and the wire rope drum 34 is unlocked. Then the rotating handle 38 is grasped and the circular plate 37 is rotated in the opposite direction, and the wire rope 31 is loosened and disengaged from the upper cover 1, and the cross pin is unloaded, and the upper cover 1 and the cross pin can be lifted in sequence.

[0040] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A universal clamp for positioning and clamping a stub shaft, comprising two sets of upper covers and lower V-shaped seats for respectively clamping the two ends of the stub shaft, wherein the upper cover is semicircular, and the semicircular inner side of the upper cover matches the outer circle of the stub shaft; a V-shaped notch for supporting the stub shaft is provided on the upper part of the lower V-shaped seat, the stub shaft is positioned in the V-shaped notch of the lower V-shaped seat, and the upper side of the stub shaft is covered by the semicircular copper sheet on the inner side of the upper cover; It is characterized in that It also includes a wire rope clamping device respectively arranged on both sides of each group of upper covers and lower V-shaped seats, the wire rope clamping device includes a wire rope, a hook base, a hook, a wire rope drum, a drum shaft, a pair of drum supports, a circular plate, a rotating handle and a ratchet pawl mechanism, the bottom of the hook base is fixed to one end of the lower part of the V-shaped seat, one end of the wire rope is fixedly connected to one end of the hook, the other end of the hook is hooked in the upper part of the hook base, the other end of the wire rope passes upward through the side groove on one side of the upper part of the lower V-shaped seat and then bypasses the semicircular groove on the outer side of the upper cover, and then The wire rope drum is fixed on the outer circumferential surface after passing through the side groove on the other side of the upper part of the lower V-shaped seat downwards; the middle part of the drum shaft is fixedly connected with the two ends of the wire rope drum, and the two ends of the drum shaft are respectively supported on the middle part of the corresponding drum support through bearings, and the bottom of the drum support is respectively fixed on the other end of the lower part of the lower V-shaped seat; the ratchet pawl mechanism is arranged between the inner side of the drum support and the end face of one end of the wire rope drum, one end of the drum shaft extends out of the drum support and is fixedly connected with the vertically arranged circular plate, and one end of the horizontally arranged rotating handle is fixed on the outer edge of the circular plate; The drum support is in an inverted T shape, the wire rope drum is embedded between the two drum supports, the ratchet pawl mechanism is arranged between the inner side of the upper part of one drum support and one end of the wire rope drum, and the other end of the wire rope drum abuts against the inner side of the upper part of the other drum support; the ends of the drum shaft are axially limited by limiting plates respectively; The ratio A / d of the semicircular groove width A to the wire rope diameter d and the ratio B / d of the side groove width B to the wire rope diameter d are both 2.3 to 2.

7.

2. The universal fixture for positioning and clamping a thick short shaft as claimed in claim 1, It is characterized in that The ratchet and pawl mechanism includes a ratchet, a pawl, a pawl pin, a tension spring and two tension spring pins. The ratchet is fixed to the drum shaft at one end of the wire rope drum through a ratchet flat key and is adjacent to the inner side surface of the upper part of a drum support; the pawl is located on the upper side of the ratchet, one end of the pawl pin crosses through the upper part of a drum support and is fixedly connected to the upper part of the drum support, the other end of the pawl pin is supported on the middle part of the pawl through a pawl pin sleeve, the middle part of the pawl is hinged to the upper part of the drum support through the pawl pin, and one end of the pawl is embedded in the tooth groove of the ratchet; one tension spring pin is fixed to the upper inner side of the corresponding drum support, and the other tension spring pin is fixed to the other end of the pawl, and the two ends of the tension spring are respectively hooked on the corresponding tension spring pins.

3. The universal fixture for positioning and clamping a thick short shaft as claimed in claim 2, It is characterized in that The other end of the ratchet pawl extends outwards to form a lever handle.

4. The universal fixture for positioning and clamping a thick short shaft as claimed in claim 1, It is characterized in that The ratio of the semicircular groove depth C to the wire rope diameter d is C / d=1.1~1.5, and the ratio of the side groove depth H to the wire rope diameter d is H / d=2.2~2.6.

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