QB/T 2919-2018 English PDF (QBT2919-2018)

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QB/T 2919-2018: Case and bag - Test method for resistance to fatigue of pull rod
QB/T 2919-2018
QB
LIGHT INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 59.140.35
Classification number. Y 48
Registration number. 63695-2018
Replacing QB/T 2919-2007
Case and bag - Test method for
resistance to fatigue of pull rod
ISSUED ON. MAY 08, 2018
IMPLEMENTED ON. SEPTEMBER 01, 2018
Issued by. Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Principles ... 4 
3 Devices ... 4 
4 Preparation of specimen ... 5 
5 Test methods ... 5 
6 Representation of results ... 6 
7 Test report ... 7 
Case and bag - Test method for
resistance to fatigue of pull rod
1 Scope
This standard specifies the principle, device, test method, test report of testing
the resistance to fatigue of pull rod of case and bag.
This standard applies to all kinds of pull rods used by case and bag.
2 Principles
At a certain pull-out and press-fitting frequency, through continuous on/off of the
pull rod’s lock as well as the reciprocating pull-out and press-fitting of the pull
rod of the case and bag, to check the reciprocating fatigue performance,
structural fastness, switch durability.
3 Devices
3.1 Reciprocating fatigue testing machine for pull rod
The reciprocating fatigue testing machine for pull rod (see Figure 1 for a
schematic diagram) shall include the components as specified in 3.1.1 ~ 3.1.8.
3.1.1 Specimen fixing device (lower clamp), which fixes the bottom of the
specimen, whose size is adjustable.
3.1.2 Pull rod’s holder (upper clamp).
3.1.3 Pull rod’s movement device, which can reciprocate, whose movement
frequency and stroke can be adjusted.
3.1.4 Support frame, the height of which is not less than 1500 mm, which is
used for installing the pull-out and press-fitting guide rail.
3.1.5 The switch device of pull rod’s lock, which can be adjusted according to
the different forms and positions of the pull rod’s lock, to automatically control
the on/off of the pull rod’s lock, without affecting the measurement of force value.
3.1.6 Force value recording device, which records the force value required
when the pull rod is pulled out and pressed in the axial direction. The force
to measure the maximum pull-out length of the pull rod, record and set the
stroke.
5.3 For the specimen with the pull rod’s lock, it shall make the lock align to the
switching device of the pull rod’s lock. Meanwhile for each pull-out and press-
fitting, the lock shall be switched on and off for one time.
5.4 Take the maximum pull-out length of the pull rod as the stroke movement
value of the pull rod. Set the pull-in stroke. Set the pull-in frequency according
to Table 1.
Table 1 -- Pull-in frequency
5.5 Select the following number of pull-in (one pull-out plus one press-fitting
forms one pull-in) to perform test. 1000 times, 2000 times, 3000 times, 5000
times, 10000 times, 20000 times, etc., or perform test according to the specified
number of pull-in. Take an interval of 5 min for each 1000 times of test.
5.6 At the end of the test, record the number of pull-in as well as the maximum
force value of pull-out and press-fitting.
5.7 Check whether the pull rod is deformed, whether the joint is loosened,
whether the switch of pull rod’s lock is normal.
6 Representation of results
The results are expressed by the number of pull-in of pull rod as well as the
quality of product after the test.
- The number of pull-in of pull rod is recorded based on the number of pull-
in at the end of the test;
- If it fails to reach the setting number of tests due to the jamming of pull rod
or other quality issues in the course of test, it shall terminate the test; whilst
the test results of fatigue performance of pull rod is expressed by the
number of pull-in at the time of terminating the test;
- Whether the pull rod is subjected to deformation, loosening components, or
damage;
- Record the maximum force value of the pull-out and press-fitting of the pull
rod, in the unit of Newton (N), the result retains an integer.
Length of pull rod / mm Pull-in frequency / (times/min)