RAT Re-Stow Pump Drive Shaft Linkage for Fast Retraction
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Solution Overview
Problem
Existing manual hydraulic pumps for re-stowing ram air turbines (RATs) are laborious, time-consuming, and difficult to operate, especially in harsh weather conditions, requiring extensive manual stroking and hydraulic pressure generation.
Innovation Solution
A drive system for a RAT re-stow pump that utilizes a rotatable drive shaft connected to a power tool, converting rotary motion into linear reciprocal motion of the pump piston via an elongate link member, allowing for automated operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual hydraulic pump is used to stow the RAT, then the RAT can be retracted, but extensive manual stroking is required which is physically difficult and time-consuming
Solution Approach 1:
The patent replaces the manual mechanical pump operation with a power-driven system. A power tool motor drives a rotary converter mechanism that transforms rotational motion into linear reciprocating motion of the pump piston, automatically generating hydraulic pressure without manual lever operation. This substitution eliminates the need for extensive manual stroking while maintaining the hydraulic retraction function.
Solution Approach 2:
The patent employs a rotary converter mechanism that converts continuous rotational motion into periodic reciprocating linear motion. The eccentric cam or crank mechanism creates automatic periodic strokes of the pump piston, generating continuous hydraulic pressure cycles without manual intervention. This periodic automatic action replaces the manual back-and-forth lever operation.
2Volume of stationary object
If a manual hydraulic pump with small displacement is used, then the pump structure can be compact, but over 100 strokes are required to generate sufficient hydraulic pressure
Solution Approach 1:
The patent replaces manual pumping with a power-driven system that can operate at higher speeds. The power tool motor provides sufficient torque to drive the pump at rapid reciprocating speeds, generating the required hydraulic pressure in far fewer cycles. This allows the use of a compact small-displacement pump while achieving high productivity through automated high-speed operation.
Solution Approach 2:
The patent changes the operating parameters of the pump system by introducing powered驱动 instead of manual operation. The power-driven system can achieve higher stroke frequencies and greater force application, transforming the pump's performance characteristics from slow manual operation to rapid automated operation, thereby increasing productivity without increasing pump size.
3Loss of time
If a power-driven system is used to replace manual pumping, then operation time is reduced, but the device complexity increases
Solution Approach 1:
The patent utilizes a power tool motor, which is a commercially available multi-functional device, as the prime mover. This universal power source can provide the required torque and speed for driving the pump mechanism. By leveraging an existing multi-functional component rather than designing a dedicated motor, the system achieves power-driven operation with minimal additional complexity.
Solution Approach 2:
The patent introduces a rotary converter mechanism as an intermediary between the rotational output of the power tool and the linear reciprocating motion required by the pump piston. This intermediary mechanism (eccentric cam, crank, or similar) efficiently transforms motion types while adding minimal complexity. The converter acts as a simple mechanical translator that bridges the power source and the pump without requiring complex control systems.
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
Reduces physical effort and time required for re-stowing the RAT, enabling quick and efficient retraction by converting rotary motion to linear motion with a power tool, reducing the time from minutes to seconds.
Implementation Method 1
rotation of the drive member is translated via the link member rotating with and pivoting relative to the drive member to linear movement of the pump piston
Data Source
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AI summary
A drive system for operating a RAM air turbine, RAT, re-stow pump assembly comprising a pump piston and a cylinder in which the pump piston moves axially in a reciprocating linear motion when driven by the drive system, the drive system comprising: a rotary drive shaft (20); and a linear link member (30) having a first end (32) connected to the rotary drive shaft and a second end (34) arranged to be connected, in use, to the pump piston of the RAT re-stow pump, whereby rotation of the drive shaft (20) is translated to reciprocal linear motion of the piston when connected to the link member, via the link member (30), and wherein the drive shaft (20) is provided with an attachment fitting (22) configured to attach to a rotary power tool, in use, to drive rotation of the drive shaft.