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Spring Type Brake Shoe Lock Key of Freight Railcar Brake Assembly Component

Spring Type Brake Shoe Lock Key of Freight Railcar Brake Assembly Component

Product No.：202681152250
Price：nogotiation
Material：high-quality carbon steel
Standard：AAR or GB
mould charge：yes
Production time：60
weight：6kg
Package：Wooden Box
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Product Overview

The Railway Brake Shoe Key (also referred to as a brake shoe locking key or retaining key) is a critical fastener used to detachably connect a brake shoe to its brake head in railcar brake assemblies . Inserted through a keyway formed by the interfitting parts of the brake head and brake shoe backing plate, this component creates a secure mechanical connection that withstands the vibrations and shocks of railway service .

The spring type brake shoe key is manufactured to AAR S-376 specifications, representing the industry standard for North American freight railcar applications. Unlike traditional wedge-type keys which rely on a wedging effect and are subject to accelerated wear, the spring type key maintains tension when installed, providing consistent retention force throughout service and preventing loosening due to vibration .

Key Features & Technical Benefits

Feature	Technical Benefit
AAR S-376 Standard Compliance	Conforms to Association of American Railroads specifications, ensuring 100% interchangeability with existing brake head and brake shoe designs
Spring Steel Construction	Manufactured from hardened and tempered spring steel, providing optimal spring tension and fatigue resistance under repeated loading
Spring Tension Retention	Creates spring-loaded engagement when driven into position; takes up play between brake head and shoe, preventing impact wear from vibration
Open-Loop Head Design	Features stop leg and pry leg with space for pry bar insertion, facilitating easy removal even when key is fully driven to locking position
Locking Detent Feature	Offset notch engages brake head latch portion in initial locking position, preventing undesired displacement in service
Corrugated Shank	Corrugations on bottom arcuate section provide positive engagement with brake head keyway opening
Designed for Quick Replacement	Allows tool-less installation with hammer drive; removal with standard pry bar using accessible head design

Quick Specifications

Parameter	Specification
Product Type	Brake Shoe Retaining Key / Locking Key
Standard Compliance	AAR S-376 (Alternate Standard)
Key Type	Spring Type (under tension when installed)
Material	Spring Steel / Heat-treated Steel
Profile	Generally curvilinear shank with open-loop head
Locking Mechanism	Spring tension + detent notch engagement
Main Application	Freight Cars, Railcars, Locomotive Brake Assemblies

Technical Data Sheet – AAR S-376 Spring Type Railway Brake Shoe Key

1. Scope of Application

This document defines the technical requirements, design specifications, and performance criteria for the spring type railway brake shoe key intended for use on freight cars, railcars, and railway braking systems. The brake shoe key is a removable fastener used to attach a brake shoe to its associated brake head, allowing for periodic replacement of worn brake shoes .

2. Applicable Standards & References

Standard	Subject
AAR S-376	Brake Shoe Keys – Specification and dimensional requirements
AAR M-1001	Freight Car Brake Rigging Specifications
ASTM A109	Steel Strip, Cold-Rolled, Carbon

3. Functional Description

The brake shoe key serves as the primary retention mechanism between the brake shoe and brake head. When installed, the key is driven through a keyway formed by:

The brake head – providing the structural support and keyway opening
The brake shoe backing plate – featuring a central mounting lug with a slot for key passage

The spring-type key is designed to be under tension when properly installed, with the spring load flexing the key into secure engagement, preventing relative movement between the brake shoe and brake head during service .

4. Key Type Comparison

Two principal types of brake shoe keys are recognized in the railroad industry :

Key Type	Description	Application
Wedge Type	Tapered design from head to foot; retained by wedging effect	Traditional design; subject to accelerated wear
Spring Type	Manufactured from spring steel; retained by tension	AAR S-376 alternate standard; widely used in North America

5. Construction & Geometry

The spring type brake shoe key consists of the following components :

Component	Description
Shank	Elongated body with generally curvilinear profile; includes arcuate section and generally straight section
Head	Open-loop configuration at top of key; includes stop leg outturned from shank face and pry leg spaced-apart from stop leg
Stop Leg	Outturned from one face of shank at angle generally less than 90°; engages brake head in locking position
Pry Leg	Spaced-apart from stop leg on opposite side; shorter than stop leg; provides space for pry bar insertion
Bight Portion	Interconnects stop leg and pry leg; forms open-loop configuration
Offset / Notch	Provides locking detent with brake head latch portion in initial locking position
Corrugations	Formed on bottom arcuate section; engage brake head keyway opening

6. Material Specifications

Parameter	Specification	Reference
Material	Spring Steel / Carbon Steel	AAR Alternate Standard
Form	Flat strip of spring metal
Heat Treatment	Hardened and tempered	As required for spring characteristics

7. Design Features

7.1 Spring Tension Retention
The key is designed to maintain spring tension when installed, taking up play between the brake head and shoe and preventing impact wear due to vibration .

7.2 Open-Loop Head Configuration
The open-loop design provides a space between the stop leg and pry leg where a pry bar may be inserted, regardless of the degree of insertion of the key—even when fully driven to locking position where stop leg abuts brake head .

7.3 Locking Detent
An offset notch intermediate the key head and bottom end engages the brake head latch portion in the initial locking position, providing positive latching force under spring tension to prevent dislodgement in service .

7.4 Corrugated Bottom
Corrugations on the bottom arcuate section provide positive engagement with the brake head keyway opening .

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