Tolerance measuring tool

Abstract

The invention discloses a tolerance measuring tool, and relates to the technical field of machining, and the key points of the technical scheme are that the tolerance measuring tool comprises an adjusting rod, the adjusting rod is provided with four groups of adjusting slip rings capable of freely sliding, and the adjusting slip rings are in threaded connection with first locking screws in a penetrating manner, and the first locking screws are used for fixing the relative positions of the adjusting slip rings on the adjusting rod; wherein two groups of adjusting sliding rings are provided with positioning steel balls used for supporting the outer surface of a part, the other two groups of adjusting sliding rings are respectively provided with a dial indicator and an auxiliary supporting rod, and the auxiliary supporting rod is used for being matched with the dial indicator to support or clamp the part. According to the invention, the dial indicator is movably arranged on the adjusting rod, so that the dial indicator can relatively slide on the adjusting rod, and then the dial indicator and the auxiliary supporting rod can clamp medium and large rectangular and tubular parts by matching with the relative distance adjustment of the auxiliary supporting rod, or support the tubular parts from the inside, so that the tolerance of the tubular parts can be conveniently measured; and the efficiency of quality inspection work is improved.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing, and in particular to a tolerance measuring tool. Background Art

[0002] After the finishing of medium and large cylindrical parts and rectangular parts is completed, it is generally necessary to inspect the outer diameter, inner diameter or length, width and other dimensional accuracy of the parts. In particular, for the inspection of the inner and outer diameter tolerances and the length and width tolerances of batch finished parts, the use of medium and large inner and outer diameter micrometers and other precision measuring tools is time-consuming, labor-intensive, and inefficient, and will also increase the cost of purchasing various measuring tools for enterprises.

[0003] In view of this, a design or technical improvement is now proposed to solve the above problems.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention, and do not constitute an admission that the above contents are the closest prior art. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned shortcomings and provide a tolerance measuring tool.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A tolerance measuring tool comprises an adjusting rod, on which four groups of freely slidable adjusting rings are arranged, and the adjusting rings are all threaded with a first locking screw for fixing the relative position of the adjusting rings on the adjusting rod; two groups of the adjusting rings are provided with positioning steel balls for supporting the outer surface of a part, and the other two groups of the adjusting rings are respectively provided with a micrometer and a secondary support rod, and the secondary support rod is used to cooperate with the micrometer to support or clamp the part.

[0008] Furthermore, a sleeve is provided at the center of the adjusting rod, and a positioning component for positioning is detachably provided at the lower end of the sleeve.

[0009] Furthermore, the positioning assembly includes a positioning shaft rod slidably sleeved in the sleeve, a cross-frame cylinder plate arranged at the end of the positioning shaft rod away from the sleeve, two groups of telescopic plates sleeved at both ends of the cross-frame cylinder plate and telescopically movable synchronously, a support plate arranged at the end of the telescopic plate away from the cross-frame cylinder plate and having a rubber pad on the upper end, and a second locking screw threaded through the cross-frame cylinder plate and engaging with the outer surface of the telescopic plate.

[0010] Furthermore, a fixed clamp arm is provided on the adjusting slip ring provided with a micrometer, and the micrometer is provided on the fixed clamp arm; the micrometer includes a dial, a measuring rod which telescopes and slides in the dial, and a probe provided at one end of the measuring rod away from the dial, and a mounting frame is provided on the fixed clamp arm, and a marking pen which is parallel to the measuring rod and can move forward and backward is provided on the mounting frame; a transmission mechanism is provided between the measuring rod and the marking pen, so that when the measuring rod telescopes and moves, the marking pen moves toward the end in the same direction as the probe.

[0011] Furthermore, a fixing plate is provided on the inner surface of the mounting frame, a limiting sliding rod is provided on the fixing plate, a suspension plate movably connected to the limiting sliding rod is provided on the marking pen, and a first spring is provided between the fixing plate and the suspension plate.

[0012] Furthermore, the transmission mechanism includes a tolerance component that limits movement on the fixed plate and a transmission component that is arranged between the tolerance component and the marking pen; the tolerance component is connected to the measuring rod and drives the marking pen to move through the transmission component.

[0013] Furthermore, the tolerance assembly includes a limit plate arranged on a fixed plate, a bearing frame sliding on the limit plate, a bidirectional threaded screw with a bearing connected to the bearing frame, and two groups of tolerance plates threadedly connected to the bidirectional threaded screw and moving relatively synchronously; the bearing frame is movably connected to the limit plate through limit slots opened on both sides; and a trigger plate located between the two groups of tolerance plates is provided on the measuring rod.

[0014] Furthermore, the transmission assembly includes a first rack plate arranged on the bearing frame, a transmission gear rotatably arranged on the fixed plate and meshing with the first rack plate, a second rack plate arranged on the marking pen and meshing with the transmission gear, and a lower suspension plate arranged on the marking pen and movably engaged with one end of the first rack plate away from the transmission gear; under normal conditions, the end of the first rack plate away from the lower suspension plate is in a critical state of engagement and separation with the transmission gear.

[0015] Furthermore, the fixed plate is provided with a side extension plate, and a positioning plate for aligning the trigger plate to the middle position between the two groups of tolerance plates is rotatably provided on the side extension plate.

[0016] Furthermore, the marking pen includes a pen barrel and a marking pen core that can be telescopically slid in the pen barrel, and a second spring is arranged between the marking pen core and the inner wall of the pen barrel.

[0017] Compared with the prior art, the beneficial effect of the present solution is as follows: the present invention movably sets the micrometer on the adjusting rod so that it can slide relatively on the adjusting rod, and then cooperate with the relative distance adjustment of the secondary support rod, so that the two can clamp medium and large rectangular and tubular parts, or support the tubular parts from the inside, and then can conveniently measure their tolerances, thereby improving the efficiency of quality inspection work.

[0018] The present invention is also provided with a marking pen, and a transmission mechanism is provided between the measuring rod and the marking pen, so that when the micrometer detects that the dimensional tolerance of a part does not meet the requirements, the marking pen will extend forward to mark the measuring part, thereby enabling the staff to clearly observe the unqualified dimensional part of the part for later adjustment and trimming. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 It is a front perspective schematic diagram of the present invention;

[0021] Figure 2 It is a schematic diagram of the state of measuring the outer diameter of a tubular part according to the present invention;

[0022] Figure 3 It is a schematic diagram of the state of measuring the inner diameter of a tubular part according to the present invention;

[0023] Figure 4 It is a partial cooperation schematic diagram of the fixed clamp arm and the micrometer in the present invention;

[0024] Figure 5 It is a schematic diagram of the relative positions of the marking pen and the measuring rod in the present invention;

[0025] Figure 6 is a cross-sectional perspective schematic diagram of the mounting frame of the present invention;

[0026] Figure 7 It is a structural schematic diagram of the transmission mechanism in the present invention;

[0027] Figure 8 is a schematic diagram of the structure of the tolerance component in the present invention;

[0028] Fig. 9 It is a cross-sectional stereoscopic schematic diagram of the pen holder of the present invention.

[0029] In the figure: 1, adjusting rod; 11, adjusting slip ring; 12, first locking screw; 13, positioning steel ball; 14, micrometer; 15, auxiliary support rod; 2, sleeve; 21, positioning shaft rod; 22, cross frame plate; 23, telescopic plate; 24, support plate; 25, second locking screw; 3, fixed clamp arm; 31, dial; 32, measuring rod; 33, probe; 34, mounting frame; 35, marking pen; 4, fixing plate; 41, limit 1. a first spring; 2. a first stopper; 3. a second spring; 4. a second stopper; 5. a first stopper; 6. a first gear plate; 7. a second gear plate; 8. a second gear plate; 9. a second gear plate; 10. a second gear plate; 11. a second gear plate; 12. a second gear plate; 13. a second gear plate; 14. a second gear plate; 15. a second gear plate; 16. a second gear plate; 17. a second gear plate; 18. a second gear plate; 19. a second gear plate; 20. a second gear plate; 21. a second gear plate; 22. a second gear plate; 23. a second gear plate; 24. a second gear plate; 25. a second gear plate; 26. a second gear plate; 27. a second gear plate; 28. a second gear plate; 29. ​​a second gear plate; 30. a second gear plate; 31. a second gear plate; 32. a second gear plate; 33. a second gear plate; 34. a second gear plate; 35. a second gear plate; 36. a second gear plate; 37. a second gear plate; 38. a second gear plate; 39. a second gear plate; 40. a second gear plate; 41. a second gear plate; 42. a second gear plate; 43. a second gear plate; 44. a second gear plate; 45. a second gear plate; 46. a second gear plate; 47. a second gear plate; 48. a second gear plate; 49. a second gear plate; 50. a second gear plate; 51. a second gear plate; 52. a second gear plate; 53. a second gear plate; 54. a second gear plate; 55. a second gear plate; 56. a second gear plate; 57. a second gear plate; 58. a second gear plate; DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0031] like Figure 1-9A tolerance measuring tool shown in the figure comprises an adjusting rod 1, on which four groups of freely slidable adjusting rings 11 are arranged, and the adjusting rings 11 are all threaded with first locking screws 12 for fixing the relative positions of the adjusting rings 11 on the adjusting rod 1; two groups of adjusting rings 11 are provided with positioning steel balls 13 for supporting the outer surface of the parts, and the other two groups of adjusting rings 11 are respectively provided with micrometers 14 and auxiliary support rods 15, and the auxiliary support rods 15 are used to cooperate with the micrometers 14 to support or clamp the parts. By setting the adjusting rings 11, The micrometer 14 can slide freely on the adjusting rod 1, thereby expanding the scale of tolerance measurement of the micrometer 14. Specifically, when measuring, first determine the specifications of the part and prepare the standard parts of the corresponding specifications, place the tool on the standard parts, and slide the adjusting slip ring 11 so that the positioning steel ball 13 at its upper end is supported on the upper surface of the part. For example, when measuring the outer diameter of a tubular part, slide the positioning steel ball 13 to make it abut against the upper end surface of the pipe mouth, then slide the micrometer 14 and the auxiliary support rod 15 to make them located on both sides of the outer diameter of the part. The end position is adjusted and clamped, and then the micrometer 14 is pressed against the surface of the part for a certain distance, and the first locking screw 12 on the adjusting slip ring 11 is rotated respectively, and the positioning steel ball 13, the micrometer 14 and the auxiliary support rod 15 are positioned, and then the micrometer 14 is zeroed, and then the positioned tool is transferred to the part to be measured, so as to measure the part tolerance according to the value change on the micrometer 14. On the contrary, when measuring the inner diameter of a tube or a rectangular part, the position of the adjusting slip ring 11 on the adjusting rod 1 can be adaptively changed according to the aforementioned adjustment method. During measurement, the micrometer 14 is aligned with the axis of the secondary strut 15, while the axis of the positioning steel ball 13 is perpendicular to the axis of the micrometer 14 and the secondary strut 15, thereby ensuring measurement accuracy. At the same time, in order to ensure that when the adjusting slip ring 11 is adjusted, the positioning steel ball 13, the micrometer 14 and the secondary strut 15 at the upper end thereof will not rotate relative to each other, resulting in an angular deviation relative to the axis, a sliding slot 9 can be provided on the adjusting rod 1, and a convex plate 91 that can be engaged and slid in the sliding slot 9 can be provided in the adjusting slip ring 11, so that no angular deflection will occur when the adjusting slip ring 11 is slidably adjusted.

[0032] In one embodiment, a sleeve 2 is provided at the center of the adjusting rod 1, and a positioning assembly for positioning is detachably provided at the lower end of the sleeve 2, the positioning assembly comprising a positioning shaft 21 slidably sleeved in the sleeve 2, a cross-frame cylinder plate 22 provided at the end of the positioning shaft 21 away from the sleeve 2, two sets of telescopic plates 23 sleeved at both ends of the cross-frame cylinder plate 22 and telescopically movable synchronously, a supporting plate 24 provided at the end of the telescopic plate 23 away from the cross-frame cylinder plate 22 and having a rubber pad provided at the upper end, and a second locking screw 25 threadedly connected to the cross-frame cylinder plate 22 and abutting against the outer surface of the telescopic plate 23. When measuring a tubular part, it is necessary to make the center of the adjusting rod 1 coaxial with the center of the part. In order to facilitate finding the center of the part, a positioning assembly is set up to assist. First, the telescopic plate 23 on the positioning assembly is synchronously extended to both sides so that it is supported on the inner wall of the tubular part. Then, the second locking screw 25 is tightened to fix the telescopic plate 23. Then, the sleeve 2 on the adjusting rod 1 is sleeved on the positioning shaft 21, so that its center position can be located on the central axis of the tubular part. At the same time, the adjusting rod 1 is rotated on the positioning shaft 21 to quickly measure the peripheral part of the part, thereby improving the detection efficiency.

[0033] In one embodiment, a fixed clamp arm 3 is provided on the adjusting slip ring 11 provided with a micrometer 14, and the micrometer 14 is provided on the fixed clamp arm 3, and its installation form can be adhesive fixation or screw fixation; the micrometer 14 includes a dial 31, a measuring rod 32 that telescopes and slides in the dial 31, and a probe 33 that is provided at one end of the measuring rod 32 away from the dial 31, and a mounting frame 34 is provided on the fixed clamp arm 3, and a marking pen 35 that is parallel to the measuring rod 32 and can move forward and backward is provided on the mounting frame 34; a transmission mechanism is provided between the measuring rod 32 and the marking pen 35, so that when the measuring rod 32 telescopes and moves, the marking pen 35 They all move toward one end in the same direction as the probe 33. In order to facilitate the staff to quickly find the part with unqualified tolerance during the measurement process, a marking pen 35 is provided. During the detection process, the micrometer 14 is in contact with the outer surface of the part through the measuring rod 32 at its upper end. When the tolerance is larger or smaller, the measuring rod 32 will correspondingly extend and retract, so that the reading on the dial 31 changes. Through the extension and retraction of the measuring rod 32, it cooperates with the transmission mechanism to drive the marking pen 35 to extend into the surface of the part, and then mark its surface position, so as to record the error point here, thereby facilitating the staff to locate.

[0034] In one embodiment, a fixing plate 4 is provided on the inner surface of the mounting frame 34, a limit slide bar 41 is provided on the fixing plate 4, a suspension plate 42 movably connected to the limit slide bar 41 is provided on the marking pen 35, and a first spring 43 is provided between the fixing plate 4 and the suspension plate 42. Through the setting of the first spring 43, when the measuring rod 32 is transferred from the position where the part tolerance is unqualified to the position where the tolerance is qualified, the marking pen 35 can be automatically reset, and then separated from the surface of the part so as not to mark the qualified position. It should be noted that in the initial state, the front end of the marking pen 35 should be a certain distance backward relative to the probe 33, so that the marking pen 35 will not directly contact the surface of the part during measurement, and only when the micrometer 14 measures the part tolerance unqualified part, the marking pen 35 will extend into its surface for marking. The specific relative position of the marking pen 35 and the probe 33 can be set according to the actual measurement situation, so as to achieve the above-mentioned effect.

[0035] In one embodiment, the transmission mechanism includes a tolerance component that is movable in an upper limit position on the fixed plate 4 and a transmission component that is arranged between the tolerance component and the marking pen 35; the tolerance component is connected to the measuring rod 32, and the marking pen 35 is driven to move through the transmission component. The tolerance component includes a limit plate 5 arranged on the fixed plate 4, a bearing frame 51 that slides in an upper limit position on the limit plate 5, a bidirectional threaded screw 52 whose bearing is connected to the bearing frame 51, and two groups of tolerance plates 53 that are threadedly connected to the bidirectional threaded screw 52 and move relatively synchronously; the bearing frame 51 is movably connected to the limit plate 5 and slides through the limit slots 54 opened on both sides; the measuring rod 32 is provided with a trigger plate 55 located between the two groups of tolerance plates 53. Since it is inevitable that there will be certain dimensional errors in the production process of parts, this error is the tolerance, and when the size of the tolerance is within a certain range, it meets the requirements of the part specification, and therefore belongs to the qualified tolerance part. In order to ensure When the micrometer 14 measures the tolerance qualified part on the part, the marking pen 35 will not mark this place, and thus it is necessary to ensure that the measuring rod 32 will not touch the transmission component within a certain telescopic range. Therefore, by setting the tolerance component, the telescopic action of the measuring rod 32 is transmitted to the transmission component through the tolerance component. The tolerance component is further provided with two sets of tolerance plates 53, and after the micrometer 14 is zeroed, the trigger plate 55 on the measuring rod 32 is located in the middle position between the two sets of tolerance plates 53. Therefore, when the measuring rod 32 performs forward and backward telescopic activities within the allowable range, the trigger plate 55 at its upper end will not contact the tolerance plate 53, and thus will not touch the tolerance component. When the trigger plate 55 moves to abut against the tolerance plate 53 and pushes it to drive the bidirectional threaded screw 52 to move as a whole, the tolerance here is driven to exceed the standard range, which belongs to the unqualified tolerance part, and then the marking pen 35 is driven to move through the transmission component to mark the position.

[0036] In one embodiment, the transmission assembly includes a first rack plate 6 disposed on the bearing frame 51, a transmission gear 61 rotatably disposed on the fixed plate 4 and meshed with the first rack plate 6, a second rack plate 62 disposed on the marking pen 35 and meshed with the transmission gear 61, and a lower suspension plate 63 disposed on the marking pen 35 and movably engaged with one end of the first rack plate 6 away from the transmission gear 61; under normal conditions, the end of the first rack plate 6 away from the lower suspension plate 63 is in a critical state of engagement and separation with the transmission gear 61, and when the tolerance plate 53 is abutted and touched by the trigger plate 55, the bidirectional threaded screw 52 will drive the shaft The bearing frame 51 moves forward and backward. When it moves forward, the first rack plate 6 at its upper end will abut against the lower hanging plate 63, thereby driving the marking pen 35 to extend forward. When the bearing frame 51 moves backward, the first rack plate 6 will mesh with the transmission gear 61 and drive the transmission gear 61 to rotate. The transmission gear 61 drives the second rack plate 62 meshed at the upper end to move forward by rotating, thereby also causing the marking pen 35 to extend forward. Therefore, through this structure, when the measuring rod 32 moves forward or backward due to the detection of an unqualified part of the part tolerance, the marking pen 35 can extend forward to mark the surface of the part.

[0037] In one embodiment, the fixed plate 4 is provided with a side extension plate 7, and a positioning plate 71 for aligning the trigger plate 55 to the middle position between the two sets of tolerance plates 53 is rotatably provided on the side extension plate 7. When the dial 31 is zeroed, the measuring rod 32 needs to be retracted inward to a certain extent, so that when the micrometer 14 detects that the surface size of the part is smaller than the size of the standard part, the measuring rod 32 will extend forward to change the reading on the dial 31, thereby facilitating measurement. The retracted distance of the measuring rod 32 must ensure that the trigger plate 55 is located between the two sets of tolerance plates. The middle part between the difference plates 53 can ensure that the positive and negative values ​​of the qualified tolerance are equal, and then by setting the positioning plate 71, it can be rotated to a horizontal state, and then the trigger plate 55 is abutted, so as to facilitate the alignment of the trigger plate 55 and zeroing the dial 31, and after the alignment is completed, there is no need to rotate the positioning plate 71 immediately to release the trigger plate 55, it can be released after being placed on the part to be tested, thereby ensuring that when the tool is placed on the part to be tested, the marker pen 35 will not extend into the surface of the part in advance to cause unnecessary markings.

[0038] In one embodiment, the marking pen 35 includes a pen barrel 8 and a marking pen core 81 that is telescopically slidable in the pen barrel 8. A second spring 82 is provided between the marking pen core 81 and the inner wall of the pen barrel 8. Since the distance between the marking pen 35 and the surface of the part is different when the micrometer 14 detects that the size of the part is larger than the standard part size and that of the part is smaller than the standard part size, and the extension and retraction of the measuring rod 32 will drive the marking pen 35 to extend the same distance, in order to ensure that the marking pen 35 can be pressed against the surface of the part for marking in either case, the marking pen 35 is set as a marking pen core. The form of 81 being sleeved in the pen barrel 8 enables it to have a certain amount of telescopic activity, and at the same time, in conjunction with the second spring 82, the marking pen core 81 has a certain degree of flexibility and adaptability, and then the marking pen core 81 is set to a position where its extension can abut against the surface of the part when the micrometer 14 detects that the part size is smaller than the standard part size. When it is detected that the part size is larger than the standard part size, the excessive extension of the marking pen core 81 will be offset by the part surface abutting against the marking pen core 81 to cause it to shrink into the pen barrel 8, thereby not causing jamming when rotating to measure the surface of the tubular part.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A tolerance measuring tool, characterized in that: The invention comprises an adjusting rod (1), wherein the adjusting rod (1) is provided with four groups of freely slidable adjusting rings (11), and each of the adjusting rings (11) is threadedly connected with a first locking screw (12) for fixing the relative position of the adjusting rings (11) on the adjusting rod (1); Two of the groups of adjusting slip rings (11) are provided with positioning steel balls (13) for supporting the outer surface of the parts, and the other two groups of adjusting slip rings (11) are respectively provided with a dial gauge (14) and a secondary support rod (15), and the secondary support rod (15) is used to cooperate with the dial gauge (14) to support or clamp the parts.

2. The tolerance measuring tool according to claim 1, characterized in that: A sleeve (2) is arranged at the center of the adjusting rod (1), and a positioning component for positioning is detachably arranged at the lower end of the sleeve (2).

3. The tolerance measuring tool according to claim 2, characterized in that: The positioning assembly comprises a positioning shaft (21) slidably sleeved in the sleeve (2), a cross frame cylinder plate (22) arranged at the end of the positioning shaft (21) away from the sleeve (2), two sets of telescopic plates (23) sleeved at both ends of the cross frame cylinder plate (22) and capable of synchronous telescopic movement, a supporting plate (24) arranged at the end of the telescopic plate (23) away from the cross frame cylinder plate (22) and having a rubber pad on the upper end, and a second locking screw (25) threadedly connected to the cross frame cylinder plate (22) and abutting against the outer surface of the telescopic plate (23).

4. The tolerance measuring tool according to any one of claims 1 to 3, characterized in that: The adjusting slip ring (11) provided with a dial gauge (14) is provided with a fixed clamp arm (3), and the dial gauge (14) is provided on the fixed clamp arm (3); The micrometer (14) comprises a dial (31), a measuring rod (32) which is telescopically slidable in the dial (31), and a probe (33) arranged at an end of the measuring rod (32) away from the dial (31); a mounting frame (34) is arranged on the fixed clamp arm (3); and a marking pen (35) which is parallel to the measuring rod (32) and can move forward and backward is arranged on the mounting frame (34); A transmission mechanism is arranged between the measuring rod (32) and the marking pen (35), so that when the measuring rod (32) is telescopically movable, the marking pen (35) moves toward an end in the same direction as the measuring head (33).

5. The tolerance measuring tool according to claim 4, characterized in that: The inner surface of the mounting frame (34) is provided with a fixing plate (4), a limiting sliding rod (41) is provided on the fixing plate (4), the marking pen (35) is provided with a suspension plate (42) movably connected with the limiting sliding rod (41), and a first spring (43) is provided between the fixing plate (4) and the suspension plate (42).

6. The tolerance measuring tool according to claim 5, characterized in that: The transmission mechanism comprises a tolerance component movable in an upper limit position on a fixed plate (4) and a transmission component arranged between the tolerance component and a marking pen (35); The tolerance assembly is connected with the measuring rod (32) and drives the marking pen (35) to move through the transmission assembly.

7. The tolerance measuring tool according to claim 6, characterized in that: The tolerance assembly comprises a limit plate (5) arranged on a fixed plate (4), a bearing frame (51) which is limitedly slidable on the limit plate (5), a bidirectional threaded screw (52) whose bearing is connected to the bearing frame (51), and two groups of tolerance plates (53) which are threadedly connected to the bidirectional threaded screw (52) and move relatively synchronously. The bearing frame (51) is movably engaged with the limiting plate (5) and slides on the limiting plate (5) through limiting grooves (54) provided on both sides; The measuring rod (32) is provided with a trigger plate (55) located between the two groups of tolerance plates (53).

8. The tolerance measuring tool according to claim 7, characterized in that: The transmission assembly comprises a first rack plate (6) arranged on the bearing frame (51), a transmission gear (61) rotatably arranged on the fixed plate (4) and meshing with the first rack plate (6), a second rack plate (62) arranged on the marking pen (35) and meshing with the transmission gear (61), and a lower hanging plate (63) arranged on the marking pen (35) and movably abutting against an end of the first rack plate (6) away from the transmission gear (61); Under normal conditions, the end of the first rack plate (6) away from the lower suspension plate (63) is in a critical state of engagement and separation with the transmission gear (61).

9. The tolerance measuring tool according to any one of claims 7 or 8, characterized in that: The fixed plate (4) is provided with a side extension plate (7), and a positioning plate (71) is rotatably provided on the side extension plate (7) for aligning the trigger plate (55) to the middle position between the two groups of tolerance plates (53).

10. The tolerance measuring tool according to claim 9, characterized in that: The marking pen (35) comprises a pen barrel (8) and a marking pen core (81) which is telescopically slidable in the pen barrel (8), and a second spring (82) is arranged between the marking pen core (81) and the inner wall of the pen barrel (8).

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