A blind end stepped bore depth and bore diameter measuring gauge and method

Abstract

The application provides a blind-end stepped hole depth and aperture measuring gauge and a method thereof, comprising a digital display dial gauge, a locking knob, a main sleeve, a sliding sleeve limiting mechanism, a sliding sleeve, a telescopic measuring rod, a conical sliding block, a measuring blade, a rubber rope, a fixed check ring, a compression spring and a movable check ring. The application has the beneficial effects that the blind-end stepped hole depth and diameter size can be quickly and conveniently measured in a closed or not open area, and the connection requirement of a new blind-end single-face installation fastener can be met by using the special blind-end stepped hole fastener, and the connection reliability of the connected product can be greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of fastener assembly and connection technology, and in particular relates to a measuring tool and method for measuring the depth and diameter of blind-end stepped holes. Background Technology

[0002] In aerospace and marine fields, different parts have different requirements for connecting pairs. Some connecting pairs require high tensile strength, some require high fatigue resistance, and some require excellent sealing performance. These connecting pairs with different performance requirements not only have strict and special requirements for fasteners, but also have high requirements for the structure and precision of the connecting holes. Only when the mounting holes and fasteners achieve the best matching form can the performance of the connecting pair reach the optimal design requirements. In aerospace and marine equipment assembly, some connected parts are fully enclosed areas or non-open areas, requiring the use of blind-end single-sided mounting fasteners. In recent years, with the development of model designs, some newly designed blind-end mounting fasteners must be used with blind-end stepped holes to achieve the best installation effect. However, blind-end stepped holes are extremely difficult to machine and inspect because tools and hands cannot reach the blind end for operation. Without dedicated machining tools and measuring instruments, the scrap rate is high, which can easily lead to the scrapping of the entire component.

[0003] This patent addresses blind-end fasteners that require installation with blind-end stepped holes in the aerospace and marine fields. It proposes a method for detecting the depth and diameter of blind-end stepped holes and also invents a measuring tool for measuring the depth and diameter of blind-end stepped holes.

[0004] To solve the problems of low machining accuracy, inability to detect dimensions, and high scrap rate of blind-end stepped holes, the newly designed detection method and measuring instruments should have the following four characteristics: 1. Simple and easy to operate.

[0005] 2. High measurement accuracy. 3. High efficiency. Summary of the Invention

[0006] In view of this, the present invention aims to provide a measuring tool and method for measuring the depth and diameter of blind-end stepped holes, so as to solve the problems of low machining accuracy, low efficiency and high scrap rate of blind-end stepped holes.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] A measuring instrument for measuring the depth and diameter of a blind-end stepped hole includes a digital dial indicator, a locking knob, a main sleeve, a sliding sleeve limiting mechanism, a sliding sleeve, a telescopic measuring rod, a tapered sliding block, a measuring blade, a rubber rope, a fixed retaining ring, a compression spring, and a movable retaining ring. The digital dial indicator is mounted to one side of the top of the main sleeve via the locking knob. The sliding sleeve is slidably fitted onto the outside of the main sleeve via the sliding sleeve limiting mechanism. The telescopic measuring rod is installed inside the main sleeve, and its bottom is mounted to the tapered sliding block. Several measuring blades are provided around the perimeter of the sleeve. The side of each measuring blade closest to the conical sliding block is located inside the main sleeve, and the side of each measuring blade furthest from the conical sliding block passes through the inner wall of the main sleeve and the inner wall of the sliding sleeve and is located outside the sliding sleeve. Fixed retaining rings are installed at the bottom of the multiple measuring blades. The fixed retaining rings are located inside the main sleeve, and a compression spring is provided below the fixed retaining rings. The movable retaining ring is located at the bottom inside the main sleeve. The upper end of the movable retaining ring passes through the compression spring and the fixed retaining ring in sequence and is threaded to the bottom of the conical sliding block.

[0009] Furthermore, the lower part of the main sleeve is provided with four symmetrical rectangular sliding grooves, which are matched with the measuring blades. The upper part of the main sleeve is provided with two symmetrical blind holes, which are used to place the sliding sleeve limiting mechanism.

[0010] Furthermore, the lower part of the sliding sleeve is provided with four symmetrical trapezoidal slots, which are used to match the main sleeve and the measuring blade. The upper part of the sliding sleeve is provided with two symmetrical stepped through holes, which are used to house the sliding sleeve limiting mechanism. The sliding sleeve is also provided with a linear slide groove connected to the stepped through holes, which is used to match the sliding sleeve limiting mechanism.

[0011] Furthermore, the sliding sleeve limiting mechanism includes a first limiting spring, a limiting post, a second limiting spring, and a button. One end of the first limiting spring is installed in the blind hole, and the other end of the first limiting spring is installed in one end of the limiting post. The other end of the limiting post is in contact with the button. The button is located in the stepped through hole, and a second limiting spring is also installed in the stepped through hole. The second limiting spring is sleeved on the outer wall of the button.

[0012] Furthermore, the surface of the conical sliding block is provided with two symmetrical through narrow rectangular slots, through which the rubber rope passes.

[0013] Furthermore, the right inclined surface of the measuring blade is used in conjunction with the conical sliding block, the left inclined surface of the measuring blade is used in conjunction with the inclined surface of the sliding sleeve, and the upper and lower parallel surfaces of the measuring blade are used in conjunction with the rectangular sliding groove of the main sleeve.

[0014] Furthermore, the upper smooth rod of the movable retaining ring is threaded, and the bottom of the tapered sliding block is provided with a threaded hole for installing the upper smooth rod of the movable retaining ring.

[0015] A method for measuring the depth and diameter of a blind-end stepped hole includes the following steps;

[0016] S1. Use measuring tools to measure the diameter of the blind end stepped hole to be measured;

[0017] S2. Use measuring tools to measure the depth of the blind end stepped hole to be measured;

[0018] S3. Remove the measuring tool from the blind end stepped hole to be measured.

[0019] Furthermore, in step S1, the diameter of the blind end stepped hole to be measured is measured using a measuring tool, including the following steps:

[0020] S11. Insert the lower part of the measuring instrument into the step hole of the blind end to be measured;

[0021] S12. Continue inserting the measuring tool to measure the wall of the step hole at the blind end of the blade.

[0022] S13. Continue inserting the measuring tool. The hole wall of the blind end step hole to be measured drives the four measuring blades to retract radially until the measuring tool is fully inserted into the blind end step hole to be measured.

[0023] S14. Continue inserting the measuring tool. When the measuring blade passes through the blind end step hole to be measured, the measuring blade slides outward and pops out under the drive of the compression spring until it hits the hole wall of the blind end step hole to be measured.

[0024] S15. The value displayed by the digital dial indicator is the diameter of the blind end stepped hole to be measured by the measuring instrument.

[0025] Furthermore, in step S2, the depth of the blind-end stepped hole to be measured is measured using a measuring tool, including the following steps:

[0026] S21. Record the depth dimension on the outer wall of the sliding sleeve in step S15, and record the dimension value as the initial value A;

[0027] S22. Continue inserting the measuring tool. When the measuring tool has completely passed through the stepped hole of the blind end to be measured, the measuring blade continues to pop outward.

[0028] S23. Press the upper bottom surface of the four measuring blades against the surface of the blind end step hole plate to be measured. At this time, record the depth dimension on the outer wall of the sliding sleeve and record the dimension value as the termination value B.

[0029] S23. Subtract the termination value B from the initial value A in step S21 to obtain the calculated depth H of the blind end stepped hole.

[0030] Furthermore, in step S3, the measuring instrument is withdrawn from the blind end stepped hole to be measured, including the following steps:

[0031] S31. Pinch the unlock button of the sliding sleeve limit mechanism on the sliding sleeve with your hand. The unlock button drives the limit column to retract into the linear groove on the sliding sleeve, thus completing the unlocking between the sliding sleeve and the main sleeve.

[0032] S32. Pinch the sliding sleeve and move it upward. After the trapezoidal groove on the sliding sleeve touches the inclined surface on the measuring blade, it forces the measuring blade to retract into the main sleeve until it is completely retracted into the main sleeve.

[0033] S33. Remove the measuring instrument from the step hole at the blind end to be measured to complete the measurement process.

[0034] Compared with the prior art, the blind-end stepped hole depth and diameter measuring instrument and method described in this invention have the following advantages:

[0035] The present invention discloses a measuring tool and method for measuring the depth and diameter of blind-end stepped holes. Using the present invention, the depth and diameter of blind-end stepped holes can be measured quickly and conveniently in closed or closed areas. When used with dedicated blind-end stepped hole fasteners, it can meet the connection requirements of new blind-end single-sided mounting fasteners and greatly improve the connection reliability of the connected products. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 This is a cross-sectional schematic diagram of the overall structure of the measuring tool according to an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram showing the depth and diameter of the blind-end stepped hole to be measured according to an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the main sleeve according to an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of the sliding sleeve limiting mechanism according to an embodiment of the present invention;

[0041] Figure 5 This is a schematic diagram of the sliding sleeve according to an embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram of the conical sliding block according to an embodiment of the present invention;

[0043] Figure 7This is a schematic diagram of the measuring blade according to an embodiment of the present invention;

[0044] Figure 8 This is a schematic diagram of the movable retaining ring according to an embodiment of the present invention;

[0045] Figure 9 This is a schematic diagram of the gauge guide section inserted into the blind end stepped hole according to an embodiment of the present invention;

[0046] Figure 10 This is a schematic diagram showing the measuring blade of the measuring instrument being fully inserted into the stepped hole according to an embodiment of the present invention;

[0047] Figure 11 This is a schematic diagram of the measuring tool for measuring the diameter of the blind end stepped hole of the blade according to an embodiment of the present invention;

[0048] Figure 12 This is a schematic diagram illustrating the measurement of the blind end stepped hole depth using a measuring tool according to an embodiment of the present invention.

[0049] Figure 13 This is a schematic diagram showing the comparison before and after the measurement blade is retracted, as described in an embodiment of the present invention.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Digital dial indicator; 2. Locking knob; 3. Main sleeve; 4. Sliding sleeve limiting mechanism; 4-1. Limiting spring No. 1; 4-2. Limiting post; 4-3. Limiting spring No. 2; 4-4. Button; 5. Sliding sleeve; 5-1. Linear slide; 6. Telescopic measuring rod; 7. Conical sliding block; 8. Measuring blade; 9. Rubber rope; 10. Fixed retaining ring; 11. Compression spring; 12. Movable retaining ring. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0056] like Figures 1 to 13 As shown, a measuring tool for measuring the depth and diameter of a blind-end stepped hole is described. The basic structure of this measuring tool is as follows: Figure 1 As shown. Firstly, this measuring instrument mainly consists of a digital dial indicator 1, a locking knob 2, a main sleeve 3, a sliding sleeve limiting mechanism 4, a sliding sleeve 5, a telescopic measuring rod 6, a conical sliding block 7, a measuring blade 8, a rubber rope 9, a fixed retaining ring 10, a compression spring 11, and a movable retaining ring 12. This measuring instrument can measure the depth and diameter of a blind-end stepped hole from one side of the connecting hole. It mainly relies on the measuring instrument releasing and retracting the measuring blade at the blind end of the connected part to measure the diameter and depth of the blind-end stepped hole. The basic principles of each component are as follows:

[0057] Digital dial indicator 1 is a device for displaying measured values ​​digitally. Locking knob 2 is mainly used to fix digital dial indicator 1 onto the main sleeve 3, such as... Figure 3As shown, the lower part of the main sleeve 3 is provided with four symmetrical rectangular sliding grooves, which are matched with the measuring blade 8 to allow the measuring blade 8 to slide radially. The upper part of the main sleeve 3 is provided with two symmetrical blind holes for housing the sliding sleeve limiting mechanism 4. The sliding sleeve limiting mechanism 4 is as follows: Figure 4 As shown, the sliding sleeve limiting mechanism 4 is mainly used for locking and unlocking the sliding sleeve 5 and the main sleeve 3. The sliding sleeve 5 is as follows: Figure 5 As shown, the lower part of the sliding sleeve 5 has four symmetrical trapezoidal slots, which are used in conjunction with the main sleeve 3 and the measuring blade 8. These slots allow the measuring blade 8 to pass through. The trapezoidal slots are used to control the measuring blade 8 to retract into the main sleeve 3. The upper part of the sliding sleeve 5 has two symmetrical stepped through holes for housing the sliding sleeve limiting mechanism 4. It also has linear grooves connected to the stepped through holes, which are used in conjunction with the sliding sleeve limiting mechanism 4 to control its linear sliding movement along the outer wall of the main sleeve 3. The telescopic measuring rod 6 is always in a compressed state during use, pressing against the conical sliding block 7. The conical sliding block... Figure 6 As shown, it works in conjunction with the measuring blade 8 to convert the axial sliding of the conical sliding block 7 into the radial sliding of the measuring blade 8. It also has two symmetrical through-type narrow rectangular slots through which the rubber rope 9 can pass. The measuring blade 8... Figure 7 As shown, it is an irregular pentagon. The right inclined surface cooperates with the conical sliding block 7, the left inclined surface cooperates with the inclined surface of the sliding sleeve 5, and the upper and lower parallel surfaces cooperate with the rectangular groove of the main sleeve 3. In use, the rubber rope 9 pulls the two symmetrical measuring blades 8 tightly against the inclined surface of the conical sliding block 7. The fixing ring 10 is attached to the bottom of the measuring blade 8 and embedded in the groove on the main sleeve 3. It is in a fixed state relative to the main sleeve 3. The movable ring 12 is as follows: Figure 8 As shown, the upper smooth rod has threads that can be screwed into the bottom threaded hole of the tapered sliding block 7, and a compression spring 11 is provided between the fixed retaining ring 10 and the movable retaining ring 12.

[0058] This invention specifically relates to a method and measuring tool for measuring the depth and diameter of blind-end stepped holes. Using this invention, the depth and diameter of blind-end stepped holes can be measured quickly and conveniently in closed or closed areas. When used with dedicated blind-end stepped hole fasteners, it can meet the connection requirements of new blind-end single-sided mounting fasteners and greatly improve the connection reliability of the connected products.

[0059] The assembly process of this measuring tool is as follows: First, assemble the main sleeve 3 and the sliding sleeve 5 together. After assembly, the sliding sleeve limiting mechanism 4 will completely lock the main sleeve 3 and the sliding sleeve 5, and the four rectangular slots on the main sleeve 3 and the sliding sleeve will be completely aligned. Then, the fixed retaining ring 10 is installed into the main sleeve 3, and the compression spring 11 is installed into the main sleeve. Then, the movable retaining ring 12 and the conical sliding block are connected together. Finally, the four measuring blades 8, the rubber elastic rope 9, and the conical sliding block 7 are connected and assembled together. Initially, under the elastic force of the compression spring, the movable retaining ring will be driven to move downward. The movable retaining ring will drive the conical sliding block to move downward. During the downward movement of the conical sliding block, the four measuring blades 8 will be driven to move outward until the conical sliding block stops moving after hitting the fixed retaining ring. At this time, the extension of the measuring blades 8 will also reach its maximum. Finally, the digital dial indicator 1 is installed into the main sleeve 3, the relative position is adjusted to ensure that the telescopic measuring rod 6 is in a suitable elastic state, and then the locking knob 2 is tightened to complete the assembly of the entire measuring tool.

[0060] A method for measuring the depth and diameter of a blind-end stepped hole, the measurement process of which is as follows: First, in order to measure the size of the blind-end stepped hole of a component, the front half of the entire measuring instrument needs to be inserted into the blind-end stepped hole to be measured, such as... Figure 9 As shown, during the continued insertion of the measuring tool, the measuring blades will encounter the wall of the blind-end stepped hole. As insertion continues, the hole wall will drive the four measuring blades to retract radially until the measuring tool is fully inserted into the hole. Figure 10 As shown. Continue inserting the measuring tool. When the measuring blade passes through the stepped hole, it will slide outward and pop out under the drive of the compression spring until it hits the wall of the stepped hole, as shown. Figure 11 As shown, the value displayed on the digital dial indicator at this point is the diameter D of the blind-end stepped hole measured by the measuring tool. Record the depth dimension A on the outer wall of the sliding sleeve. Continue inserting the measuring tool. When the tool has completely passed through the blind-end stepped hole, the measuring blades will continue to pop outwards. At this point, retract the measuring tool so that the lower surfaces of the four measuring blades are fully against the blind-end plate surface. Record the depth dimension B on the outer wall of the sliding sleeve. Subtract the previously recorded initial value A from this value to obtain the depth dimension H of the blind-end stepped hole, H = BA. This completes the measurement of the depth of the blind-end stepped hole.

[0061] The process of the measuring instrument exiting the blind end stepped hole is as follows: Pinch the unlocking button 4-4 of the sliding sleeve limiting mechanism 4 on the sliding sleeve 5. This will drive the limiting post 4-2 to retract into the linear groove 5-1 on the sliding sleeve 5. At this point, the sliding sleeve 5 and the main sleeve 3 are unlocked. The sliding sleeve 5 can then slide along the linear groove. Then, pinch the sliding sleeve and move it upwards. When the trapezoidal groove on the sliding sleeve touches the inclined surface on the measuring blade, it will cause the measuring blade to retract into the main sleeve until it is completely retracted into the main sleeve. Figure 13 As shown, the measuring tool can now be removed from the stepped hole, thus completing the entire measurement process.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A blind-end stepped bore depth and bore diameter measuring gauge, characterized by: The utility model provides a kind of telescopic measuring rod, including digital dial dial gauge (1), locking knob (2), main sleeve (3), sliding sleeve limiting mechanism (4), sliding sleeve (5), telescopic measuring rod (6), conical sliding block (7), measuring blade (8), rubber rope (9), fixed check ring (10), compression spring (11) and movable check ring (12), the digital dial dial gauge (1) 1 is installed to main sleeve (3) top side by locking knob (2), the main sleeve (3) outside is slidably sleeved sliding sleeve (5) by sliding sleeve limiting mechanism (4), telescopic measuring rod (6) is installed in the main sleeve (3) inside, telescopic measuring rod (6) bottom is installed to conical sliding block (7), the outer wall of conical sliding block (7) is circumferentially equipped with several measuring blades (8), each measuring blade (8) is close to conical sliding block (7) one side and located in the main sleeve (3) inside, each measuring blade (8) is away from conical sliding block (7) one side and located in the outside of sliding sleeve (5) after passing through the inner wall of main sleeve (3), the inner wall of sliding sleeve (5), the bottom of multiple measuring blades (8) is installed fixed check ring (10), the fixed check ring (10) is located in the main sleeve (3) inside, compression spring (11) is arranged below the fixed check ring (10), movable check ring (12) is located in the bottom of main sleeve (3) inside, the upper end of movable check ring (12) is sequentially connected to the bottom of conical sliding block (7) after passing through compression spring (11), fixed check ring (10) threadedly; The lower part of the sliding sleeve (5) is provided with four symmetrical trapezoidal grooves, which are matched with the main sleeve (3) and the measuring blades (8) for use, the upper part of the sliding sleeve (5) is provided with two symmetrical stepped through holes for placing the sliding sleeve limiting mechanism (4), and the sliding sleeve (5) is further provided with a linear sliding groove (5-1) connected with the stepped through hole, which is matched with the sliding sleeve limiting mechanism (4) for use.

2. A depth and bore diameter measuring gauge for blind stepped bore according to claim 1, characterized in that: The lower part of the main sleeve (3) is provided with four symmetrical rectangular grooves, which are matched with the measuring blades (8) for use, and the upper part of the main sleeve (3) is provided with two symmetrical blind holes for placing the sliding sleeve limiting mechanism (4).

3. A depth and bore diameter measuring gauge for blind stepped bore according to claim 1, characterized in that: The sliding sleeve limiting mechanism (4) comprises a limiting spring (4-1), a limiting column (4-2), a second limiting spring (4-3) and a button (4-4), one end of the limiting spring (4-1) is installed in the blind hole, the other end of the limiting spring (4-1) is installed at one end of the limiting column (4-2), the other end of the limiting column (4-2) is in abutting connection with the button (4-4), the button (4-4) is located in the stepped through hole, and the second limiting spring (4-3) is also installed in the stepped through hole, and the second limiting spring (4-3) is sleeved on the outer wall of the button (4-4).

4. A depth and bore diameter measuring gauge for blind stepped bore according to claim 1, characterized in that: The surface of the conical sliding block (7) is provided with two symmetrical narrow-slit rectangular grooves for the rubber rope (9) to pass through. The right side slope of the measuring blade (8) is matched with the conical sliding block (7), the left side slope of the measuring blade (8) is matched with the slope of the sliding sleeve (5), and the upper and lower parallel surfaces of the measuring blade (8) are matched with the rectangular sliding groove of the main sleeve (3).

5. A depth and bore diameter measuring gauge for blind stepped bore according to claim 1, characterized in that: The upper light rod of the movable blocking ring (12) is provided with threads, and the bottom of the conical sliding block (7) is provided with a threaded hole for installing the upper light rod of the movable blocking ring (12).

6. A method for measuring the depth and diameter of a blind stepped hole, applied to the blind stepped hole depth and diameter measuring gauge according to any one of claims 1-5, characterized in that: The method comprises the following steps. S1, using a measuring tool to measure the hole diameter of the blind end stepped hole to be measured; S2, using a measuring tool to measure the hole depth of the blind end stepped hole to be measured; S3, withdrawing the measuring tool from the blind end stepped hole to be measured.

7. A method of measuring the depth and diameter of a blind stepped hole according to claim 6, wherein: In step S1, using a measuring tool to measure the hole diameter of the blind end stepped hole to be measured, comprises the following steps: S11, inserting the lower part of the measuring tool into the blind end stepped hole to be measured; S12, continuing to insert the measuring tool, and the measuring blade (8) hits the hole wall of the blind end stepped hole to be measured; S13, continuing to insert the measuring tool, and the hole wall of the blind end stepped hole to be measured drives the four measuring blades (8) to shrink radially until the measuring tool is completely inserted into the blind end stepped hole to be measured; S14, continuing to insert the measuring tool, and when the measuring blade (8) passes through the blind end stepped hole to be measured, the measuring blade (8) slides out under the driving of the compression spring (11) until it hits the hole wall of the blind end stepped hole to be measured; S15, the numerical value displayed by the digital dial gauge (1) is the hole diameter of the blind end stepped hole to be measured measured by the measuring tool.

8. A method of measuring the depth and diameter of a blind stepped hole according to claim 7, wherein: In step S2, using a measuring tool to measure the hole depth of the blind end stepped hole to be measured, comprises the following steps: S21, recording the depth size on the outer wall of the sliding sleeve (5) in step S15, and recording the size value as the initial value A; S22, continuing to insert the measuring tool, and when the measuring tool completely passes through the blind end stepped hole to be measured, the measuring blade (8) continues to pop out; S23, abutting the lower bottom surface of the four measuring blades (8) against the plate surface of the blind end stepped hole to be measured, and at this time, recording the depth size on the outer wall of the sliding sleeve (5) and recording the size value as the termination value B; S23, subtracting the termination value B of step S23 from the initial value A of step S21 to obtain the calculated blind end stepped hole depth size H.

9. A method of measuring the depth and diameter of a blind stepped hole according to claim 8, wherein: In step S3, withdrawing the measuring tool from the blind end stepped hole to be measured, comprises the following steps: S31, holding the unlocking button (4-4) of the sliding sleeve limiting mechanism (4) on the sliding sleeve (5) with hands, and the unlocking button (4-4) drives the limiting column (4-2) to retreat into the linear sliding groove (5-1) on the sliding sleeve (5), and the unlocking between the sliding sleeve (5) and the main sleeve (3) is completed; S32, holding the sliding sleeve (5) to move upward, and after the trapezoidal inclined groove on the sliding sleeve (5) hits the slope on the measuring blade (8), the measuring blade (8) is forced to shrink into the main sleeve (3) until it is completely received in the main sleeve (3); S33, taking out the measuring tool from the blind end stepped hole to be measured, and completing the measuring process.

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