Test Method For Longitudinal Stiffness Of Leather Shoes

Test method for longitudinal stiffness of leather shoes

1 theme content and scope of application

This standard specifies the test method for the longitudinal flexural rigidity of leather shoes.

This standard is applicable to the determination of the longitudinal bending rigidity of leather shoes.

2 Principle

The rear end of the hook is fixed and loaded at the front end of the hook, resulting in bending deformation and measuring the bending deflection of the hook so as to calculate the bending rigidity of the hook.

3 sample

3.1 the sample is the finished product.

3.2 0.5h must be placed at room temperature before testing.

3.3 each grade is three with the same specification.

4 instrument

4.1 the hook type stiffness tester includes an adjustable back end fixture with hook core, a hooking center front fixture and a dial indicator for measuring deflection (see Figure 1).

4.2 the rear end fixture of the hook is made up of two clamping claws. Each claw is 32mm long and has two bars to clamp the hook. The thickness of the rib is 6mm, and the front rib of the upper jaw has a central slot, a width of 6mm, and a depth of 4mm.

The front ribs of the lower jaw are inclined planes with a inclination of 10 degrees, so as to ensure that the length of the arm is accurate and unchanged.

4.3 the rear end fixture of the hook can rotate around the horizontal axis so as to adjust the clamping center so that the front and the two clamping points are on the same horizontal plane.

The angle that the fixture can be placed from the horizontal position must not be less than 30 degrees.

4.4 the front end fixture consists of two parts: clamps and loading lugs.

The clamp consists of two flat splint 12mm thickness.

The lower splint has a width of 6mm wider than that of the upper splint. On its upper surface there is a V groove across the plate along the centerline of the plate.

4.5 the splint can hold the ear of the hanging weight, and there are two horizontal coaxial pins on the sides of the supporting ears. The two pins are placed in the V groove on the upper surface of the lower splint.

The axis of the pin is higher than the 1.0mm of the upper surface of the splint.

The surface roughness of V groove and pin shaft Ra is 0.8 m.

The 4.6 dial indicator is used to measure the deflection of the hook when it is bent, and its position can be adjusted to place the measuring foot on the center point of the upper surface of the loading ear.

4.7 weights and dial meters are periodically checked according to the state regulations.

5 test procedure

5.1 the top of the hook will be raised, and the back end will be inserted into the rear end fixture, so that the ends will be aligned with the rear edge of the fixture to ensure that the hook is clamped on the 32mm, and the hook is perpendicular to the back edge of the fixture. The ribs of the hook are in the slot of the fixture, and the clamp is screwed tightly.

5.2 use the two splint of the front end clamp to clamp the front part of the hook. Use the special fixture to make the distance between the lower splint edges of the front and the back clamps 60mm, adjust the inclination of the fixture, make the front and the two clamping points on the same horizontal plane (visually), tighten two manual knobs, and fix the rear fixture.

5.3 adjust the position of the dial indicator, so that its supporting rod is perpendicular to the upper surface of the loading support, and the supporting foot is aligned to the center point of the upper surface of the supporting ear.

Lower the dial gauge until its short needle rotates to 9, then tighten the knob to fix the dial gauge position and adjust the dial indicator long needle point zero.

5.4 hang the 200g weight on the hook of the loading ear. When loading 5S, read the table value A1 (by long needle), then increase the 200g weight, 5S read the table value A2, so doing, you can get the table value A3 and A4.

5.5 remove the loading lug.

5.6 test the remaining two hooks in the same way.

6 calculation of test results

6.1, according to (1) computer hook deflection.

A = 1/10 (3 AI 4 + a 3 - Al 2 - 3 Al 1)......

(1)

Type: a dates, each hangs 200g weight to make the deflection of the hook, mm;

A1 jujube hangs 200g weight to make the deflection of the hook, mm;

A2 jujube hangs 400g weight to make the deflection of the hook, mm;

A3 jujube hangs 600g weight to make the deflection of the hook, mm;

A4 jujube hangs 800g weight to cause the deflection of the hook, mm.

6.2 calculate the bending stiffness of hook core according to (2) formula.

S = 9.81/106 * WL3/3a......

(2)

Type: S jujube hook core flexural rigidity, kN. Mm2;

W the weight of jujube weights, 200g;

A jujube hook deflection, mm

L jujube bending arm, 66mm.

6.3 the S values of three hooks are respectively expressed.

When the a value is less than 1mm, the S value takes the two digit effective number; when the a value is greater than 1mm, the three digit effective number is obtained.

7 test report

7.1 indicate that the tests are carried out according to this standard.

7.2 sample number, name, brand name, specification (length * width * thickness), hook number (male, female, heel height), material, production plant and inspection unit.

7.3 test results

7.4 test personnel and dates.

Additional instructions:

This standard is put forward by the quality standard Department of light industry department.

This standard is centralized by the national shoe standardization center.

This standard is drafted by the Scientific Research Institute of shoemaking industry of Ministry of light industry.

The main draftsman of this standard: Gao Zhi Xing Zhou Jing.

This standard is equivalent to the British standard BS 5191/4.18:1985 "test method for longitudinal stiffness of steel hooked core".