Crane Boom Locking Head Motion Mitigator for Stuck Pins
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Solution Overview
Problem
Existing telescoping boom systems, particularly those with hydraulic trombone cylinders, face issues such as entrained air, cold temperatures, and pressure deflection, which can cause coupling pins or lock arms to become stuck, leading to delayed boom operations.
Innovation Solution
The proposed solution is a locking head assembly for a telescoping boom that incorporates a motion mitigator. This assembly includes a locking head with a base, an operating plate, cylinder pins, and section lock arms, along with an actuator and a motion mitigator. The motion mitigator consists of a housing, a rod, and a biasing device, which helps to mitigate movement issues by applying a biasing force when movement is inhibited.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydraulic trombone cylinder is used to actuate the locking head, then the locking mechanism can be operated, but entrained air and cold temperatures cause the coupling pins or lock arms to become stuck
Solution Approach 1:
The patent replaces the hydraulic trombone cylinder with an electric linear actuator that has a rigid rod and piston design, eliminating the flexible hose and hydraulic fluid that trap air. The electric actuator provides direct mechanical drive without compressible intermediaries, solving the sticking problem caused by entrained air in hydraulic systems.
Solution Approach 2:
The patent changes the actuation mechanism from hydraulic to electric, fundamentally altering the physical parameters of the system. The electric linear actuator operates with incompressible mechanical connection, eliminating the compressibility issue of hydraulic fluid that causes sticking under cold temperatures and air entrapment.
2Force
If pressure within the trombone cylinder increases to drive the locking mechanism, then the coupling pins and lock arms can be actuated, but the pressure deflects the rod or cylinder and causes components to become stuck
Solution Approach 1:
The patent replaces the flexible hydraulic cylinder with a rigid electric linear actuator featuring a solid rod and piston construction. This rigid mechanical system transmits force without the deflection and misalignment problems inherent in flexible hydraulic cylinders under pressure.
Solution Approach 2:
The patent employs a bell crank mechanism that converts linear motion to rotational motion, using curved paths to accommodate force application while maintaining precise control. The bell crank's curved geometry allows force transmission without direct linear deflection of the actuator rod.
3Productivity
If the control system continues attempted operations when movement is inhibited, then the system attempts to complete the locking sequence, but this damages or causes premature wear of the linear electric drive
Solution Approach 1:
The patent incorporates feedback mechanisms including encoders that monitor the position and movement of the electric linear actuator. When the system detects that the actuator is not moving as commanded (indicating a stuck condition), the feedback signal triggers an error state that stops further actuation attempts, preventing damage to the motor and drive components.
Solution Approach 2:
The patent uses a bell crank mechanism that provides mechanical advantage, allowing the electric actuator to operate through a limited angular range rather than requiring full linear travel. This partial action approach reduces the total movement required and minimizes wear on the actuator components while still achieving the locking function.
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 motion mitigator effectively addresses the issue of stuck components by providing a biasing force that allows the operating plate to move and the cylinder pins or section lock arms to function correctly, even when they are initially stuck, thereby reducing delays in boom operations.
Implementation Method 1
a biasing device disposed between the rod and the housing
Data Source
AI summary
A locking head assembly (210) for a telescoping boom (118) of a crane (110) includes a locking head (212) having a base (218), an operating plate (220) operably coupled to the base, one or more cylinder pins (222) and/or one or more section lock arms (226) movable in response to movement of the operating plate relative to the base. An actuator (214) is operably coupled to the operating plate and configured to move the operating plate relative to the base. The actuator includes a motor (234) and a drive arm (236). The motor is configured to drive the drive arm between a drive arm first position and a drive arm second position. A motion mitigator (216) is connected to the actuator and the locking head and includes a housing (238), a rod (240) movable relative to the housing, and a biasing device (242) disposed between the rod and the housing.