Compact Gripper Device Using Screw and Pinion Motion Conversion
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Solution Overview
Problem
Conventional gripper devices with long stroke gripper claws face size increase issues due to the configuration of gears, leading to a larger overall device size, which is not adequately addressed by existing techniques.
Innovation Solution
A gripper device design featuring an air cylinder with a rotary output mechanism using a screw shaft and nut for converting rectilinear motion to rotary motion, and a pinion gear with a rack gear for increasing the stroke of gripper claws, where the nut is positioned at the inner diameter of the pinion gear to reduce the device's thickness and overall size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a long stroke air cylinder is used to increase the stroke of gripper claws, then the gripper claw stroke is increased, but the overall size of the gripper device becomes large
Solution Approach 1:
A pinion gear is introduced as an intermediary mechanism between the air cylinder and the gripper claws. The pinion gear converts the rectilinear motion of the piston rod into rotary motion, which then drives the gripper claws to move. This intermediary mechanism allows the gripper claws to achieve a larger stroke than the piston rod without requiring a long-stroke air cylinder, thereby reducing the overall device size.
Solution Approach 2:
The stroke of the gripper claws is increased by changing the parameters of the pinion gear, specifically its pitch circle diameter. By selecting an appropriate pitch circle diameter for the pinion gear, the rotary motion generated by the piston rod can be converted into a larger linear displacement of the gripper claws, achieving sufficient stroke with a compact air cylinder.
2Length of moving object
If multiple gears are arranged with considerable axial displacement to increase gripper stroke, then the gripper claw stroke is increased, but the device size in the thickness direction becomes large
Solution Approach 1:
The functions of the piston rod and the pinion gear are merged into a single integrated component. The piston rod is directly formed with pinion gear teeth, eliminating the need for a separate pinion gear component and reducing the axial displacement required. This merging allows the rotary motion generation and linear motion transmission to occur within a compact axial space, reducing the device thickness.
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
This configuration allows for a sufficient stroke of gripper claws while minimizing the size of the gripper device, particularly in the thickness direction, by adjusting the lead of the screw shaft and pitch circle diameter of the pinion gear, ensuring the gripper device does not excessively increase in size.
Implementation Method 1
a rotary output mechanism which includes a screw shaft secured to the piston rod and a nut in threaded engagement with the screw shaft, and which is configured to convert rectilinear motion of the piston rod into rotary motion
Implementation Method 2
a rectilinear output mechanism which is configured to convert the rotary motion output from the rotary output mechanism into rectilinear motion and transmit the rectilinear motion to the plurality of linear motion units, and which includes a pinion gear configured to rotate in synchronization with the nut and a rack gear engaged with the pinion gear
Data Source
AI summary
A gripper device includes: an air cylinder having a piston rod; a rotary output mechanism which includes a screw shaft and a nut and which is configured to convert rectilinear motion of the piston rod into rotary motion; a plurality of linear motion units each having a gripper claw coupled thereto; and a rectilinear output mechanism which is configured to convert the rotary motion output from the rotary output mechanism into rectilinear motion and transmit the rectilinear motion to the plurality of linear motion units, and which includes a pinion gear and a rack gear. The nut is located at an inner diameter side of the pinion gear, and rectilinear stroke of the linear motion units is greater than rectilinear stroke of the piston rod.