Hand Tool Linear Drive Mechanism with Dual Speed Gearbox
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Solution Overview
Problem
Portable hand tools with hydraulic cylinders require frequent maintenance and have elongated designs due to hydraulic pumps and linear mechanisms, and they lack efficient control mechanisms for varying loads on working implements.
Innovation Solution
A compact, lightweight linear drive mechanism using a roller screw with a multiple speed gearbox and torque adjustment system, powered by electric motors, which includes a planetary roller screw and a secondary motor for automatic torque and speed adjustments based on load sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic pumps and cylinders are used to actuate working implements, then the tool can generate sufficient force, but the housing becomes elongated and the tool requires frequent maintenance
Solution Approach 1:
The roller screw mechanism is nested within a compact housing, with the threaded shaft and nut assembly arranged in a space-efficient configuration that eliminates the need for elongated hydraulic components while maintaining force generation capability
Solution Approach 2:
The patent replaces the hydraulic cylinder and pump system with a mechanical roller screw mechanism, eliminating the need for hydraulic fluid, seals, and complex valve systems while achieving comparable force output in a more compact package
2Power
If hydraulic pumps are used to power working implements, then the tool can operate with high power, but the tool requires periodic inspection and maintenance
Solution Approach 1:
The patent replaces the hydraulic power transmission system with a direct mechanical drive using a roller screw mechanism, eliminating hydraulic fluid leaks, seal failures, and valve maintenance while maintaining high power transmission efficiency through direct mechanical contact
Solution Approach 2:
The roller screw mechanism is designed with inherent self-lubrication properties through the rolling contact between the threaded shaft and nut, reducing the need for periodic maintenance and inspection compared to hydraulic systems that require fluid level checks and seal replacements
3Adaptability or versatility
If check valves and by-pass valves are used to control hydraulic pressure, then the tool can control pressure for varying loads, but the device complexity increases
Solution Approach 1:
The patent incorporates a load sensing mechanism that automatically detects the resistance encountered by the working implement and adjusts the motor speed and torque accordingly, eliminating the need for complex valve-based pressure control systems while maintaining adaptability to varying loads
Solution Approach 2:
The system uses variable speed control of the electric motor coupled with the roller screw mechanism to dynamically adjust the force output based on load conditions, replacing static valve-based pressure control with a more responsive and simpler electronic control system
4Weight of moving object
If a compact linear drive mechanism is used, then the tool housing can be made portable and lightweight, but the mechanism must efficiently handle varying load requirements
Solution Approach 1:
The patent employs a variable speed control system that dynamically adjusts the motor operating speed based on the load requirements, allowing a compact, lightweight roller screw mechanism to efficiently handle varying loads by optimizing the speed-torque characteristics in real-time
Solution Approach 2:
The system changes the operating parameters (speed and torque) of the electric motor and roller screw mechanism based on detected load conditions, enabling a compact design to adapt to varying force requirements without requiring oversized components
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 portable, efficient, and maintainable hand tool that conserves power by adjusting torque and speed according to load requirements, enhancing performance in applications with limited input power and varying work demands.
Implementation Method 1
roller screw threaded shaft with an external nut and rollers mounted over axially aligned threaded shaft
Implementation Method 2
a coaxially carrier ring with three equal size planet gears mounted thereon. The planet gears include teeth that mesh with exterior teeth on the pinion gear
Implementation Method 3
an inner ring with a plurality of elastomeric members which resist compression. When excessive forces are exerted on the work implement, radial forces are exerted on the inner ring causing the elastomeric members to compress
Data Source
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AI summary
A hand tool with a mechanical linear drive mechanism coupled to a linear activated working implement. The drive mechanism includes a roller screw that includes a torque tube connected to a roller screw's nut body. The roller screw includes a fixed outer race, a rotating set of grooved rollers axially aligned inside the outer race, a cylindrical nut body located inside the set of grooved roller, a plurality of inner rollers axially aligned and inside the nut body, a threaded shaft axially aligned and inside the inner rollers, and a torque tube axially aligned inside the inner rollers. The torque tube is connected at one end to a multiple speed gear box which includes a primary motor coupled to a earner gear with three planet gears. Disposed around the planet gears is a ring gear. Coupled to the ring gear is a secondary motor which when activated causes the ring gear to rotate in the opposite direction of the planet gears. At least one sensor measures the rotation of an elastomeric ring and control activation of the secondary motor to change the operational speed of the tool.