Specification for sliding locking bolts for use with padlocks

IS 7534: Introduction - Key Specifications & Tables

1. Sampling & Defectives (Clause 2.2 & Table 3):

• Lot conformity depends on the number of defectives ≤ permissible number in Table 3.
• Manufacturer must provide test certificates for material compliance.

2. Material Requirements (Clause 4.1 & Table 1):

3. Dimensions of Locking Bolt (Clause 6.1 & Table 2):

• Bolt plate length, bolt length, diameter, width, thickness, and screw holes are standardized.
• Example for Type I, size 150 mm:
  • Length of bolt plate: 210 ± 1 mm
  • Length of bolt: 150 ± 2 mm
  • Diameter of bolt: 10 ± 0.5 mm
  • Width of bolt plate: 45 ± 1 mm
  • Thickness of bolt plate: 2 ± 0.10 mm

flowchart LR
    A[Lot of Locking Bolts] --> B{Sample Size per Table 3}
    B --> C{Count Defectives}
    C -->|≤ Permissible| D[Lot Conforms]
    C -->|> Permissible| E[Lot Rejected

IS 7534 - Scope: Key Formulas, Tables & Specifications

1. Scope Summary (Clause 1.3 & A-1.3)

Defines sampling and acceptance criteria for locking bolts in lots.

2. Sampling Table for Locking Bolts (Table 3)

• Lot conformity: Number of defectives ≤ permissible defectives (Clause 2.2).

3. Dimensions of Locking Bolts (Table 2, Clause 6.1)

All dimensions in millimeters.

IS 7534: Sizes and Types of Locking Bolts

Key Specifications:

• Sizes available: 110, 150, 200, 250, 300 mm (Clause 3.1)
• Bolt types:
  • Type I: Straight locking plate (Fig. 1)
  • Type II: Curved locking plate (Fig. 2)

Important Dimensions (Table 2 summary):

IS 7534: Materials and Manufacture - Key Details

1. Materials (Clause 4.1 and Table 1)

• Manufacturer must provide a test certificate confirming material conformity.

2. Manufacture (Clause 5.1.2 & 6.1, Table 2)

• Bolts are cut, bent, and riveted or spot welded at mid-length to restrict movement.
• Bolt plates and bolts have specified dimensions and tolerances (all in mm):

3. Quality Control

• Lot conformity checked against permissible defectives per Table 3 (Clause

IS 7534: Dimensions and Tolerances for Locking Bolts

Key Specifications (Clause 6.1 & Table 2)

Material (Clause 5.1.2)

• Bolts made from mild steel or aluminium alloy rods.
• Cut, bent, and riveted or spot welded mid-length to restrict movement.

Tolerances & Notes

• Clear edge distance of holes: Minimum 5 mm.
• All dimensions in millimetres.
• Aluminium thickness generally 1 mm thicker than mild steel for strength.

Summary Diagram

flowchart LR
    A[Locking Bolt] --> B(Length of Bolt Plate A)
    A --> C(Length of Bolt B)
    A --> D(Diameter of Bolt D)
    A --> E(Width of Bolt Plate E)
    A --> F(Thickness of Bolt Plate T1)
    A --> G(Thickness of Plate

IS 7534: Finish and Surface Treatment - Key Specifications

Materials & Surface Treatment (Clause 4.1 & 8.1)

• Bolt Plate & Receiving Plate:
  • Mild Steel Sheet: IS 1079-1973 (Grade 0-1079)
  • Aluminium Alloy Sheet: IS 737-1974 (Designations 52000 or 65032)
• Bolt:
  • Mild Steel Rods: IS 1977-1975 (Grade Fe 310-0)
  • Aluminium Alloy Extruded Rod: IS 733-1983 (Designations 63400 WP or 65032 WP)
• Marking: Each locking bolt must bear the manufacturer's name or trademark.

Surface Treatment

• Aluminium components may have anodic coatings as per IS anodic coatings specification (second revision) to enhance corrosion resistance.

Table Summary: Material Grades

Notes:

• Surface finish must ensure durability and corrosion resistance.
• Screws used comply with IS 6760-1972 (slotted countersunk head wood screws).
• Manufacturer to provide test certificates for material conformity.

flowchart TD
    A[Raw Material] --> B{Material Type}
    B -->|Mild Steel| C[IS 1079-1973 / IS 1977-1975]
    B -->|Aluminium Alloy| D[IS 737-1974 / IS 733-1983]
    C --> E[Manufacture Bolt & Plates]
    D --> E
    E --> F[Surface Treatment]
    F --> G[Marking Manufacturer's Name]

This ensures locking bolts meet IS 7534 quality and durability standards.

IS 7534 - Marking: Key Points & Specifications

Marking Requirements (Clause 8.1):

• Each locking bolt must be marked with the manufacturer's name or trade-mark.
• Locking bolts may also bear the ISI Certification Mark (Clause 8.1.1), which assures compliance with Indian Standards under ISI supervision.

Sampling & Conformity (Clause 2.2 & 9)

• A lot is conforming if the number of defectives in the sample is ≤ permissible defectives in Table 3, column 3.
• Manufacturer must provide a test certificate for material compliance.

Dimensions of Locking Bolt (Table 2, Clause 6.1)

IS 7534: Sampling and Criterion for Conformity

1. Sampling Scale (Table 3, Clause A-1.3)

2. Criterion for Conformity (Clause A-2.2)

• A lot conforms if the number of defectives in the sample ≤ permissible defectives (from Table 3).
• Manufacturer must provide a test certificate for material compliance (Clause 4).

3. Sampling Procedure (Clause A-1.2 & 9.1)

• Samples are taken from each lot separately.
• Testing is done on the sampled bolts to verify conformity.

Summary:

• Sample size and acceptance criteria depend on lot size.
• Zero defectives allowed for small lots (≤150).
• Acceptance increases with lot size but limited to max 3 defectives for large lots.

flowchart TD
    A[Lot of Locking Bolts] --> B[Sample Size per Table 3]
    B --> C[Test Sample]
    C --> D{Defectives ≤ Permissible?}
    D -- Yes --> E[Lot Accepted]
    D -- No --> F[Lot Rejected]

This ensures quality control by statistically validating each lot based on defect limits.

IS 7534: Sampling Procedures & Quality Control

1. Sampling Scale & Permissible Defectives (Table 3)

2. Criteria for Conformity (Clause A-2.2)

• A lot conforms if the number of defectives in the sample ≤ permissible defectives (from Table 3).
• Manufacturer must provide a test certificate for material compliance.

3. Sampling & Testing Procedure

• Samples are tested separately from each lot (Clause A-1.2).
• Final test values must be rounded off per IS 2-1960, maintaining the same significant figures as specified.

Summary:

• Use Table 3 to decide sample size and acceptance criteria.
• If defectives ≤ permissible number, lot is accepted.
• Maintain proper rounding and documentation for quality assurance.

flowchart TD
    A[Start: Lot of Locking Bolts] --> B[Determine Lot Size]
    B --> C{Lot Size}
    C -->|≤150| D[Sample 13 bolts]
    C -->|151-300| E[Sample 20 bolts]
    C -->|301-500| F[Sample 32 bolts]
    C -->|>500| G[Sample 50 bolts]
    D --> H[Count Defectives]
    E --> H
    F --> H
    G --> H
    H --> I{Defectives ≤ Permissible?}
    I -->|Yes| J[Accept Lot]
    I -->|No| K[Reject Lot]

This ensures statistically valid quality control per IS 7534.