Tiltable Ladder Rack Cam-Actuated Slide Mechanism
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Solution Overview
Problem
Existing ladder rack systems for commercial vans and work vehicles rely on rotational mechanisms that complicate the loading and unloading of ladders, requiring workers to manually rotate ladders from the vehicle roof to a side position, which is inefficient and cumbersome.
Innovation Solution
A slide-based mechanism that allows ladders to be horizontally moved along the vehicle's roof and then tilted vertically for easy access from the ground, using a cam-actuated locking system and optional motor drive for automatic operation, enabling efficient loading and unloading without contact with the vehicle body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotational lever mechanism is used to transfer ladders from the vehicle roof to the side position, then the ladder can be transferred to a accessible location, but the operation becomes complex and cumbersome requiring manual rotation
Solution Approach 1:
Instead of rotating the ladder from a horizontal roof position to a vertical side position using a complex lever mechanism, the patent inverts the approach by using a slide arrangement that moves the ladder horizontally along the roof and then automatically shifts it to a vertical disposition through a cam-actuated mechanism, eliminating the need for manual rotation
Solution Approach 2:
The patent replaces the traditional rotational lever mechanism with a slide-based system incorporating rollers, guide members, and a cam-actuated locking mechanism. This substitution transforms the rotational motion into linear sliding motion followed by automatic vertical positioning, reducing operational complexity
2Productivity
If manual rotation of ladders is required to transfer them from the vehicle roof, then the mechanism remains simple, but worker efficiency and productivity decrease
Solution Approach 1:
The slide arrangement with cam-actuated locking mechanism enables the system to automatically perform the ladder transfer operation. Once the ladder is placed on the slide mechanism, the system self-actuates through the cam mechanism to move and position the ladder vertically without requiring continuous manual intervention, thereby improving productivity while maintaining ease of operation
3Loss of time
If the ladder rack uses a traditional lever-based rotational system, then the structure remains compact, but the loading and unloading process becomes time-consuming
Solution Approach 1:
The slide arrangement is pre-positioned on the vehicle roof with guide members and rollers in place. When the ladder is placed on the slide mechanism, the preliminary setup allows the cam-actuated system to immediately initiate the transfer operation, reducing the time required for ladder loading and unloading despite the increased structural complexity
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
Facilitates easy and efficient transfer of ladders between the vehicle roof and ground positions, improving safety and reducing manual effort through a smooth, automated process that enhances operational efficiency.
Implementation Method 1
the cam follower roller enters a cam track on a first cam member affixed to the stationary bed. With rearward movement of the load support member, the cam follower roller elevates and thereby lifts the control arm
Implementation Method 2
a second cam member actuates a spring-loaded, cam-actuated locking pin that acts to latch the control arm to a latch bracket affixed to the underside of the load support member
Implementation Method 3
rollers affixed to a load support member are constrained such that the load support member can only move along the rails horizontally in translation without rotation
Data Source
AI summary
A ladder rack assembly for a work vehicle has a stationary bed for attachment to the roof thereof. A pair of parallel, spaced apart rails has guides thereon that extend from the rails' first ends toward, but short their second ends. Rollers on side edges of a load support member ride on the bed rails. When the rollers are constrained by the guides, only translation of the load support member takes place. Upon exit of the rollers from the rear ends of the guides, both translation and rotation of the load support member can occur. A control arm is pivotally joined at one end to the stationary bed. Its free end has cam actuated latch pin assemblies attached to it that co-act with cams on the stationary bed during rearward displacement of the load support member to latch the load support member to the control arm whereby further rearward movement of the load support member causes it to tilt to a somewhat vertical position.