Equalizer Bearing Assembly With Cam Wedges for Compressive Loads

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Solution Overview

Problem

Existing hook-type and bolted clamp attachments for connecting an equalizer bar to a walking beam in reciprocating pump systems fail under compressive loading, leading to structural failure and require time-consuming assembly.

Innovation Solution

A cam wedge assembly is used to connect the equalizer bar to the walking beam, featuring brackets with slots and wedges that provide a secure, compressive load-bearing mechanism through camming profiles, allowing quick assembly and preventing stress concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If hook-type or bolted clamp attachments are used to connect the equalizer bar to the walking beam, then the assembly can be simple in structure, but the connection fails under compressive loading

Engineering Contradiction:

Improveattachment structureVSAvoidcompressive load bearing capacity

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The retainer is designed with a cam wedge geometry that dynamically transforms compressive loads into lateral camming forces. As the equalizer bar applies compressive load, the cam surface of the retainer converts this axial force into a lateral force that presses the equalizer bar against the bearing shaft, creating a self-locking mechanism that prevents detachment under compression while maintaining structural simplicity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The cam wedge retainer acts as an intermediary element between the equalizer bar and the bearing shaft. It mediates the force transmission by converting compressive loads into camming actions, providing a reliable connection mechanism that handles both compression and tension loads without requiring complex multi-component assemblies

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If traditional retaining blocks and bolts are used, then the assembly process is straightforward, but the connection requires frequent inspections and maintenance

Engineering Contradiction:

Improveassembly processVSAvoidconnection stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The cam wedge retainer is designed to be self-adjusting and self-locking. As loads are applied during operation, the cam geometry automatically maintains optimal contact forces between the equalizer bar and bearing shaft, eliminating the need for periodic tightening or adjustment that would be required with traditional bolted connections. The structure serves itself by using operational loads to maintain its own secure engagement

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The dynamic camming action continuously adapts to varying operational loads, automatically adjusting the retention force to match the applied stresses. This eliminates the static, fixed-position retention of traditional blocks and bolts, providing ongoing self-correction and maintaining reliable connection without inspection or maintenance intervention

Inventive Principle:

Principle #15Dynamics

3Strength

If bolts are used to secure retaining blocks, then the connection can be initially secure, but the bolts experience bending stresses under compressive loading leading to failure

Engineering Contradiction:

Improveinitial connection securityVSAvoidbending stress on fasteners

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The invention replaces the bolted mechanical fastening system with a cam-based geometric locking system. Instead of relying on bolts to resist bending stresses, the cam wedge geometry inherently redirects compressive loads into lateral camming forces that create friction and mechanical interlocking, eliminating the need for stress-resistant fasteners and their associated bending stress problems

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cam wedge retainer serves as an intermediary that eliminates the direct load path through bolts. By introducing this geometric mediator, compressive loads are transformed into camming actions before reaching the connection interface, preventing the bending stresses that would otherwise be imposed on bolted fasteners

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The cam wedge assembly effectively withstands compressive loads, preventing structural failure and reducing the need for frequent inspections, while maintaining a robust connection between the equalizer bar and walking beam.

Implementation Method 1

Methodology Applied

Scientific EffectCamming: Cam

Data Source

PatentUS12410785B2Equalizer bearing assembly having wedged retainers

Publication Date: 2025.09.09 TRC SERVICES INC

AI summary

An assembly is used to connect an equalizer bar to a walking beam of a reciprocating pump unit. The walking beam has a bearing shaft having cylindrical ends. Brackets attached to the equalizer bar define slots, each having a hooked section and having a base section. The hooked sections are configured to rest against the cylindrical ends of the bearing shaft. The base sections of the slots oppose the hooked sections at a gap from the cylindrical ends of the bearing shaft. Wedges are configured to position in the slots between the bases and the cylindrical ends of the bearing shaft.