Templates will ensure high-quality acceptance of auto coupling parts
V.V. Strelnikova, Senior Researcher at JSC "VNIIZHT",
V.V. Matveeva, leading designer of the Design Bureau of the Carriage Industry of JSC "Russian Railways"
The problem of ensuring the interchangeability of parts of the rolling stock coupling device, coupling, as well as trouble-free and reliable operation has existed since the very beginning of the introduction of the coupling. It should be noted that the body of the automatic coupling and the details of the coupling mechanism are made by casting without subsequent machining. They have a very complicated configuration, which makes it virtually impossible to measure them with a universal measuring instrument.
First of all, this concerns the SA-3 coupling loop, which ensures the coupling of the couplings, for the basic dimensions of which the OST NKPS 6453/103 standard was developed back in 1934 (currently it is the current GOST 21447-75).
In addition, the details of the automatic coupling mechanism are in a complex kinematic interaction with each other. The clutch mechanism can work properly and accurately only if deviations from the nominal dimensions of the parts and from their nominal relative position in the housing are strictly limited.
In the 30s of the twentieth century, specialists from the Scientific Research Institute of Railway Transport (NIIHT) developed a system for accepting newly manufactured auto-coupling parts with templates. It is still being successfully used today.
This system provides the most rational and effective control over the compliance of the geometric dimensions of the parts with the requirements of the design documentation and allows you to control all the necessary dimensions to ensure the reliability of the coupler. Templates, according to the accepted system, are divided into passable and non-passable.
A passageway is a template that must pass through the measured places when checking parts, otherwise the parts are considered unusable and must be fixed or rejected.
An impassable template, on the contrary, should not pass through the measured parts. If it passes, then the parts are considered unusable.
There are a number of combined templates available. They combine the principles of pass-through and non-pass-through patterns, as well as probes.
The template-based inspection system greatly simplifies the inspection of auto-coupling parts, making the inspection process itself less time-consuming.
For example, there is only one template for checking the fuse (Fig. 1). It allows you to control the overall shape of the fuse, the thickness of the arms, the diameter of the hole, the chamfer around the hole and the height of the end surface of the upper arm.
Three templates are used for the lock holder. One of them, 826A, is shown in Fig. 2 and is used to check the counterweight, release angle and oval opening of the lock holder.
The design of the acceptance templates was improved and changed along with the design of the coupling parts (Fig. 3, 4).
The staff of the All-Union Scientific Research Institute of Railway Transport of the Ministry of Railways (TsNII MPS) carried out a lot of work to improve the control system for newly manufactured coupling parts in 1950 — 1953. Then a radical revision of the template set was required in connection with the adjustments made to the design documentation for the auto coupling parts.
A number of templates from the old set, consisting of 36 templates, had to be completely abandoned. The design of some was only changed to take into account the new size bases and permissible deviations. In addition, new templates were developed, which provided for the verification of uncontrolled or incorrectly controlled dimensions of parts.
A set of templates was experimentally used to test newly manufactured couplings at the Lublin Foundry and Mechanical Plant. Some templates have been adjusted or changed again after trial operation.
At the same time, the specialists of the Central Research Institute of the Ministry of Internal Affairs developed a "Guide for using acceptance templates for checking the CA-3 auto coupling". It is still used in the manufacturing plants of the auto coupling device parts.
Initially, the templates were designated by the numbers of the drawings of the People's Commissariat of Railways (NKPS), then by the numbers of the drawings of the Central Research Institute indicating the scope of the template. The letter "A" added to the template marking indicated that the template was used for the acceptance of newly manufactured parts, the letter "p" — the template was used for repairs.
For ease of use, markings appeared on the template: "
PR" — passable and "NOT" — non-passable templates. This designation for templates is still preserved at the present time.
It should be noted that the templates used in the repair of the coupler are derived from the templates used in its manufacture. The modern set of repair templates includes 66 templates, including installation templates and counter templates, as well as templates and crowbars for checking the automatic coupling in operation. A device has also been developed to measure the height of the coupler above the rail heads. and over the past thirty years, the set of drawings of repair templates (project T416.00) has been repeatedly adjusted at the Design Bureau of the Carriage Industry (PKB CV) according to the comments of VNIIZHTA and enterprises involved in the operation and repair of the coupling device. At the same time, the acceptance templates were not actually revised.
It was only in 1965 that the management of the Main Department of the Ministry of Railways Carriage Industry abolished the use of four templates (881A, 886A, 887A, 888A), which were used to check individual elements of the coupling housing in connection with the development of serial manufacturing technology by factories.
In 2008, JSC Russian Railways instructed PKB TSV to bring the set of documentation for the acceptance templates in line with the design documentation for the auto coupling. Specialists from the manufacturers of auto coupling parts, primarily JSC NPK Uralvagonzavod, actively participated in this work. They proposed to change a number of tolerances for the templates, thereby tightening the quality requirements. manufacturing of cast parts of the automatic coupling.
By now, the drawings are designed in computer form, taking into account modern requirements for design documentation. The template operation manual has also been redesigned.
In the third quarter of 2009, a commission of specialists from JSC "VNIIZHT", PKB CV and the Department of Technical Policy of JSC "Russian Railways" conducted acceptance tests of a pilot batch of templates. This batch was manufactured by JSC NPK Uralvagonzavod according to an already adjusted design.
Based on the positive results obtained as a result of the work of the Russian Railways commission, it was decided to apply templates according to the design of PKB CV T770.00.000 at all enterprises manufacturing parts of the coupling device.
Equipping factories with a new set of templates will ensure better acceptance of parts with verification of all sizes for reliable operation of the coupling mechanism and interchangeability of parts during assembly of automatic couplings.
Scientists and developers from JSC VNIIZHT, PKB TSV and JSC NPK Uralvagonzavod plan to continue joint work on further improving the template system for controlling parts of the automatic coupling device.
28.02.2023, 18:16
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