Bolt fuse hole symmetry degree inspection device

Abstract

The utility model discloses a bolt fuse hole symmetry degree inspection device, which belongs to the technical field of machining part detection, and comprises a core rod, an auxiliary block and a caliper, the upper surface and the lower surface of the auxiliary block are parallel, the upper surface is provided with a semicircular through groove, two sides of the through groove are provided with two coaxial arc-shaped grooves, and the two arc-shaped grooves are connected with the caliper. The diameter of the core rod is the same as that of a fuse hole of the bolt, after the core rod penetrates through the fuse hole, a stud of the bolt falls into the through groove, the core rod is embedded into the arc-shaped groove, the distance between the top face of the threaded outer circle and the lower surface of the auxiliary block is measured through a caliper, and the bolt is turned over by 180 degrees and then measured again; the symmetry error is obtained by dividing the two numerical values by 2. The caliper is high in measurement precision, and cannot be affected by the thread form in the use of the caliper.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical parts inspection technology, and relates to a device for checking the symmetry of bolt fuse holes. Background Technology

[0002] Bolt-type parts on aircraft generally require a fuse hole to be machined at the center of the threaded end (e.g. Figure 1 As shown, after the bolts are tightened with slotted nuts, cotter pins or other methods are needed for safety and to prevent loosening, thus avoiding vibration during use that could cause the nuts to come loose. During the manufacturing process, the center symmetry of the fuse hole needs to be checked. If the deviation is too large, the cotter pin will not be able to be inserted after the slotted nut is tightened. Current inspection methods generally involve direct measurement with calipers, but due to factors such as the bolt thread profile, inaccurate measurements are easily obtained. Utility Model Content

[0003] To address the difficulty in checking the symmetry of fuse holes, this invention provides a device for checking the symmetry of bolt fuse holes, which can improve the accuracy of checking the symmetry of fuse holes at bolt threads.

[0004] The present invention adopts the following technical solution:

[0005] A device for checking the symmetry of bolt fuse holes includes a mandrel 3, an auxiliary block 2, and calipers.

[0006] The upper and lower surfaces of the auxiliary block 2 are parallel. The upper surface has a semi-circular through groove with an inner diameter larger than the outer diameter of the bolt 1 thread. The upper surfaces on both sides of the through groove have two coaxial arc-shaped grooves with the axis of the arc-shaped grooves perpendicular to the axis of the through groove. The diameter of the arc-shaped grooves is the same as the diameter of the core rod 3.

[0007] The core rod 3 is a cylinder with the same diameter as the fuse hole of the bolt 1. After it passes through the fuse hole of the bolt 1, it is placed on the upper surface of the auxiliary block 2 together with the bolt 1, so that the stud of the bolt 1 falls into the through groove and the core rod 3 is embedded in the arc-shaped groove on the auxiliary block 2.

[0008] The caliper is a conventional caliper used to measure the distance between the top surface of the outer thread of bolt 1 and the lower surface of auxiliary block 2.

[0009] The advantages of this invention are: it has high measurement accuracy and is not affected by the thread profile of the caliper. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the bolt's shape.

[0011] Figure 2 This is a schematic diagram of the structure of this utility model.

[0012] Among them, 1 is a bolt; 2 is an auxiliary block; and 3 is a mandrel. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this utility model clearer, the specific embodiments of this utility model will be described in detail below.

[0014] A bolt fuse hole symmetry inspection device includes a mandrel 3, an auxiliary block 2, and calipers, such as Figure 2 .

[0015] The auxiliary block 2 is formed by cutting two parallel planes along a cylinder parallel to its axis, which serve as the upper and lower surfaces of the auxiliary block 2. The upper surface has a semi-circular through groove with an inner diameter larger than the outer diameter of the bolt 1 thread. The upper surfaces on both sides of the through groove have two coaxial arc-shaped grooves with the axis of the arc-shaped grooves perpendicular to the axis of the through groove. The diameter of the arc-shaped grooves is the same as the diameter of the core rod 3.

[0016] The core rod 3 is a cylinder with the same diameter as the fuse hole of the bolt 1. After it passes through the fuse hole of the bolt 1, it is placed on the upper surface of the auxiliary block 2 together with the bolt 1, so that the stud of the bolt 1 falls into the through groove and the core rod 3 is embedded in the arc-shaped groove on the auxiliary block 2.

[0017] The caliper is a conventional caliper used to measure the distance between the top surface of the outer thread of bolt 1 and the lower surface of auxiliary block 2.

[0018] The procedure for checking the center symmetry of the fuse hole on bolt 1 is as follows:

[0019] Step 1: Insert the mandrel 3 into the fuse hole of the bolt 1, and then place the mandrel 3 together with the bolt 1 on the upper surface of the auxiliary block 2, so that the stud of the bolt 1 falls into the through groove and the mandrel 3 is embedded in the arc-shaped groove on the auxiliary block 2.

[0020] Step 2: Hold the assembled bolt 1, auxiliary block 2, and mandrel 3, keeping the axis of bolt 1 parallel to the axis of the through groove of auxiliary block 2. Use the two jaws of a caliper to clamp onto the top surface of the outer thread of bolt 1 and the lower surface of auxiliary block 2 respectively, and measure a value. During the measurement, avoid the caliper jaws from getting stuck in the groove of the thread profile, which would lead to inaccurate measurement.

[0021] Step 3: Remove the calipers, rotate bolt 1 180° around mandrel 3, repeat step 2, and obtain the second value.

[0022] Step 4: Subtract the two values ​​and divide by 2 to get the symmetry error of the bolt fuse hole. Compare this error with the product tolerance requirements to determine whether it is qualified.

[0023] In summary, the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A device for checking the symmetry of bolt fuse holes, characterized in that, Includes a mandrel (3), an auxiliary block (2), and calipers; The upper and lower surfaces of the auxiliary block (2) are parallel. A semi-circular through groove is made on the upper surface. The inner diameter of the through groove is larger than the outer diameter of the bolt (1) thread. Two coaxial arc grooves are made on the upper surfaces on both sides of the through groove, and the axis of the arc groove is perpendicular to the axis of the through groove. The core rod (3) is a cylinder with the same diameter as the fuse hole of the bolt (1). After it passes through the fuse hole of the bolt (1), it is placed on the upper surface of the auxiliary block (2) together with the bolt (1), so that the stud of the bolt (1) falls into the through groove and the core rod (3) is embedded in the arc-shaped groove on the auxiliary block (2). The caliper is a conventional caliper used to measure the distance between the top surface of the outer circle of the bolt (1) thread and the lower surface of the auxiliary block (2).

2. The bolt fuse hole symmetry inspection device according to claim 1, characterized in that, The diameter of the arc-shaped groove of the auxiliary block (2) is the same as the diameter of the core rod (3).

3. The bolt fuse hole symmetry inspection device according to claim 1, characterized in that, When using calipers, avoid having the jaws get caught in the grooves of the thread profile.

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