Pivoting Mixer Ladder Assist for Controlled Soft-Close Deployment
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Solution Overview
Problem
Front discharge concrete mixer vehicles face challenges in safely and efficiently deploying their ladders for operator access due to the need for quick and controlled movement between stowed and lowered positions, particularly in confined spaces.
Innovation Solution
A ladder assembly with an upper and lower portion, featuring a pivotable lower ladder portion and an assist assembly that resists rotation during transition, along with a soft close mechanism to control the movement between stowed and lowered positions, ensuring safe and controlled deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lower ladder portion is manually deployed and retracted without assist mechanism, then the device complexity is reduced, but operator strain increases and safety is compromised
Solution Approach 1:
The assist mechanism is configured to automatically provide assistance during ladder deployment and retraction operations. The mechanism engages with the lower ladder portion and uses mechanical advantage to reduce the force required by the operator, allowing the system to serve itself rather than requiring full manual effort from the operator throughout the entire range of motion.
Solution Approach 2:
The assist mechanism changes the mechanical parameters of the ladder deployment process by introducing a force multiplication effect. Through the use of levers, cams, or hydraulic/pneumatic elements, the mechanism transforms the operator's input force into sufficient force to move the heavy lower ladder portion, thereby changing the force-displacement characteristics of the system.
2Productivity
If the lower ladder portion transitions quickly between positions, then productivity is improved, but sudden impacts and damage risk increase
Solution Approach 1:
The assist mechanism incorporates damping or cushioning elements that are pre-positioned to engage before the ladder portion completes its travel. These elements gradually absorb the kinetic energy of the moving ladder, preventing sudden impacts with the ground or mounting structure while still allowing for relatively quick deployment and retraction operations.
3Ease of operation
If the lower ladder portion is held in intermediate positions without assist, then the device complexity is reduced, but operator control and safety are compromised
Solution Approach 1:
The assist mechanism provides continuous mechanical feedback throughout the ladder's range of motion. As the operator moves the ladder to any position within the arc, the mechanism maintains engagement and provides proportional assistance, automatically adjusting the force applied based on the ladder's position and weight distribution, thereby enabling precise control at intermediate positions.
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 solution provides a safe and efficient mechanism for ladder deployment, enhancing operator safety and access in confined spaces while maintaining vehicle stability and control.
Implementation Method 1
The assist mechanism includes a soft close mechanism to control the descent and ascent, ensuring smooth transitions and reducing operator effort.
Implementation Method 2
The lower ladder portion is selectively repositionable between (a) a stowed position in which the lower ladder portion is disposed along the upper ladder portion and (b) a lowered position in which the lower ladder portion extends away from the upper ladder portion.
Data Source
AI summary
A concrete mixer vehicle includes a chassis, a cab, a mixer drum assembly coupled to the chassis, a ladder assembly, and an assist assembly. The chassis includes a front end and a rear end. The ladder assembly includes an upper ladder portion and a lower ladder portion. The upper ladder portion is fixed in position relative to the chassis. The lower ladder portion is pivotally coupled to the upper ladder portion and selectively repositionable between (a) a stowed position in which the lower ladder portion is disposed along the upper ladder portion and (b) a lowered position in which the lower ladder portion extends away from the upper ladder portion. The assist assembly is coupled to the upper ladder portion and the lower ladder portion. The assist assembly configured to resist the rotation of the lower ladder portion as it transitions from the stowed position to the lowered position.