Specification For Rim Latches

IS 1019 - Scope: Key Formulas, Tables & Specifications

Scope Summary:

• Covers dimensions, manufacture, and sampling of rim latches.
• Applies to mild steel, brass, aluminum alloy, and zinc base alloy latches.
• Ensures international coordination and field practice relevance.

Key Tables:

1. Dimensions of Rim Latches, Type 2 (Mild Steel) - Clause 7.2 (All dimensions in mm)

Tolerances: ±1 mm (A), ±0.5 mm (D, G, H, 3), etc.

IS 1019 - Handing of Rim Latches: Key Specifications & Tables

1. Handing of Rim Latches (Clause 2)

• The code specifies handing (right or left) based on door opening direction.
• Handing affects latch orientation and strike plate positioning.
• Ensure latch bolt projects correctly relative to door swing.

2. Dimensions & Tolerances (Clauses 7.1 & 7.2)

• Refer to Table 2 & Table 3 for detailed dimensional data (in mm).
• Dimensions include latch body size (A, B), bolt length (C), backset (D), and mounting hole positions (E, F, G, etc.).

3. Material & Manufacture (Clause 1.1 & 6.1)

• Materials: Mild steel, brass, aluminium alloy, zinc base alloy.
• Manufacturers may vary latch shape/design but must maintain functional dimensions.

Example: Mild Steel Rim Latch Type 1 (Size 100 mm)

Summary Diagram of Rim Latch Dimensions

graph LR
A[Latch Length (A)] --> B[Backset (D)]
B --> C[Bolt Length

IS 1019: Types of Rim Latches - Key Specifications

1. Type 1 Rim Latches (Clause 8.2 & Table 2)

• Material: Mild Steel (also Brass, Aluminium, Zinc alloys)
• Dimensions (mm) for Mild Steel Latches:

Tolerances apply as per Clause 7.1.

2. Type 2 Rim Latches (Clause 8.3 & Table 3)

• Material: Mild Steel (also Brass, Aluminium, Zinc alloys)
• Dimensions (mm) for Mild Steel Latches:

| Size (mm) | A | B | C | D | E

IS 1019: Standard Sizes for Rim Latches

Key Tables for Rim Latch Dimensions (All dimensions in mm)

1. Type 1 Rim Latches (Mild Steel) - Clause 7.1 (Table 2)

Tolerances: ±1 mm on A, B; +1 mm on C; ±0.5 mm on D; etc.

2. Type 2 Rim Latches (Mild Steel) - Clause 7.2 (Table 3)

| Size (mm) | A | B | C | D | E | F

IS 1019: Key Material Specifications & Dimensions for Rim Latches

1. Materials (Clause 5.1, Table 1)

2. Dimensions of Rim Latches (Clause 7.1 & 7.2)

Type 1: Mild Steel Latch (mm)

IS 1019 - Dimensions for Rim Latches

Clause 7.1: Type 1 Rim Latches (Mild Steel)

Tolerances: ±1 mm for A, B; +1 / -0.5 mm for C, D; others as per table.

Clause 7.2: Type 2 Rim Latches (Mild Steel)

| Size (mm) | A | B | C | D | E | F | G | H | I | K | L | M | N | P | e | R | T Min | TI

IS 1019 - Manufacture of Rim Latches: Key Specifications & Tables

1. Material Requirements (Clause 5.1, Table 1)

2. Dimensions of Rim Latches - Mild Steel (Clause 7.1 & 7.2)

Type 1 Rim Latch (Table 2):

IS 1019: Workmanship and Finish - Key Points

1. Workmanship Requirements (Clause 9)

• All components (back plate, follower, locking pin, spindle, knobs, disc, striking box) must meet the manufacturing quality as per Clause 8.2.
• Surfaces should be smooth, free from cracks, burrs, and sharp edges.
• Proper assembly ensuring functional movement without undue friction or looseness.

2. Dimensional Specifications (Clause 7.1 & 7.2)

• Table 2 provides dimensions for Type 1 Mild Steel Rim Latches, e.g.:

• Tolerances vary, e.g., ±1 mm for A, B; +1/-0.5 mm for C, etc.

• Table 3 (Clause 7.2) covers brass, aluminium alloy, and zinc latches (Type 2) with similar dimensional control.

3. Quality Control (Clause A-2.1)

• Rim latches must be checked for:
  • Dimensional accuracy (Clause 7)
  • Manufacturing defects (Clause 8)
  • Workmanship and finish (Clause 9)
  • Performance (Clause 10)
• Any non-conformity results in rejection.

IS 1019: Performance Requirements for Rim Latches

1. Performance Clause (10.1)

• Rim latches must satisfy specified performance requirements after final assembly, ensuring durability and functionality.

2. Key Dimensions (Clause 7.1 & 7.2)

• Dimensions are standardized for Type 1 and Type 2 rim latches (mild steel, brass, aluminum, zinc alloys).
• Sizes: 75, 100, 125, 150 mm with detailed dimensional parameters (A, B, C, ... V) in mm.
• Tolerances apply to ensure interchangeability and fit.

(Refer to Tables 2 & 3 for full dimensional details)

3. Material Finishes (Clause 9.2)

• Brass latches: Bright or satin finish.
• Aluminium latches: Anodized finish, minimum Grade AC 15 per IS 1868.
• Steel latches: Black japanned, stove enamelled black, or copper oxidized as specified.

Summary Diagram: Rim Latch Type 1 Dimensions

flowchart LR
    A(Size) --> B(A-Dimensions)
    B --> C(Tolerances)
    C --> D(Material & Finish)
    D --> E(Performance Test)

Note: Always verify latch dimensions and finishes per purchaser specifications and ensure compliance with performance testing as per Clause 10.1.

IS 1019: Sampling and Inspection Key Points

Sampling Plan (Clause 1.2, Appendix A)

• Sample size depends on lot size per Table 4:

• Sampling follows Clause 13.1 and Appendix A.

Criteria for Conformity (Clause A-3.1)

• A lot passes if defective items ≤ permissible number in Table 4.
• Otherwise, the lot is rejected.

Summary:

• Select sample size based on lot size.
• Inspect sample for defects.
• Accept lot if defects ≤ permissible limit.

flowchart TD
    A[Start: Lot Received] --> B{Determine Lot Size}
    B -->|Up to 200| C[Sample 15 items]
    B -->|201-300| D[Sample 20 items]
    B -->|301-500| E[Sample 30 items]
    B -->|501-800| F[Sample 40 items]
    B -->|801+| G[Sample 55 items]
    C --> H[Inspect Samples]
    D --> H
    E --> H
    F --> H
    G --> H
    H --> I{Defects ≤ Permissible?}
    I -->|Yes| J[Accept Lot]
    I -->|No| K[Reject Lot]

For detailed tolerances and dimensions, refer to Table 3 and Fig. 2 (Clause 7.2).

IS 1019: Criteria for Conformity - Key Points

1. Lot & Sample Size (Table 4)

• Lot: Group of rim latches produced.
• Sample Size: Number of rim latches tested from the lot.
• Permissible Defectives: Max defective rim latches allowed for lot acceptance.

2. Criteria for Conformity (Clause 3.1)

• A lot conforms if the number of defective rim latches in the sample ≤ permissible number.
• If defects exceed permissible number, the lot is not conforming.

3. Inspection Aspects (Clauses A-2.1, 7, 8, 9, 10)

• Dimensional requirements
• Manufacturing defects
• Workmanship and finish
• Performance tests

Summary:

• Use Table 4 to decide sample size and acceptance criteria.
• Inspect samples per clauses for defects.
• Accept lot if defects ≤ permissible number; else reject.

flowchart TD
    A[Select Lot] --> B[Determine Sample Size (Table 4)]
    B --> C[Test Sample Rim Latches]
    C --> D{Defectives ≤ Permissible?}
    D -- Yes --> E[Lot Accepted]
    D -- No --> F[Lot Rejected]

This ensures quality compliance for rim latches per IS 1019.

IS 1019 Appendix A: Sampling and Criteria for Conformity

Key Points:

• Sampling is based on lot size; sample size and acceptance criteria are per Table 4.
• Each selected rim latch is checked for:
  • Dimensional requirements (Clause 7)
  • Manufacturing defects (Clause 8)
  • Workmanship and finish (Clause 9)
  • Performance (Clause 10)
• A latch failing any check is considered defective.

Table 4: Sampling & Acceptance Criteria

Criteria for Conformity:

• Lot is accepted if defective latches ≤ permissible defects in Table 4.
• Otherwise, the lot is rejected.

Summary Diagram:

flowchart TD
    A[Start: Lot Received] --> B[Determine Lot Size]
    B --> C[Select Sample Size per Table 4]
    C --> D[Inspect Sample for Dimensions, Defects, Finish, Performance]
    D --> E{Number of Defective Latches ≤ Permissible Defects?}
    E -->|Yes| F[Accept Lot]
    E -->|No| G[Reject Lot]

This ensures quality control by statistically sampling and enforcing strict defect limits based on lot size.