Gripper Sensor Mechanism for Single and Double Sheet Detection
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Solution Overview
Problem
Current gripper systems require two sensors or switches to distinguish between a single workpiece and multiple workpieces, increasing cost, size, and weight, which is inefficient and undesirable.
Innovation Solution
A single sensor or switch mechanism using a pivoting linkage and cam system that converts linear motion to rotational motion, allowing differentiation between one and multiple workpieces by positioning a target within an arc, thereby reducing the overall cost, size, and weight of the gripper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two sensors or switches are used to detect single vs. multiple workpieces, then detection reliability is improved, but cost, size, and weight increase
Solution Approach 1:
The cam slot is segmented into distinct zones (first zone for no workpiece, second zone for single workpiece, third zone for multiple workpieces) that correspond to different sensor output states. This segmentation allows a single sensor to detect multiple conditions by monitoring the position of the cam follower along the segmented cam slot path.
Solution Approach 2:
A cam mechanism acts as an intermediary between the workpiece loading condition and the sensor. The cam converts the linear position of the follower (determined by workpiece thickness) into rotational motion that moves a target through distinct angular zones, enabling the sensor to distinguish between different loading conditions through the target's position.
2Measurement precision
If two sensors or switches are used to distinguish workpiece quantity, then detection accuracy is improved, but gripper size increases
Solution Approach 1:
The solution transitions from a linear arrangement of multiple sensors to a rotational dimension using a cam mechanism. The cam slot is shaped to create large angular displacement from small linear changes in follower position, amplifying the detection signal and enabling precise measurement of workpiece quantity through angular position rather than requiring multiple linearly-spaced sensors.
3Reliability
If two sensors or switches are used to detect clamping conditions, then detection capability is improved, but weight increases
Solution Approach 1:
The cam mechanism merges the functions of multiple sensors into a single detection system. By combining the cam slot geometry, follower motion, and single sensor into an integrated mechanism, the system achieves the same detection capability as multiple sensors would provide, but with reduced weight and complexity.
4Device complexity
If a single sensor is used with direct linear sensing, then device simplicity is improved, but detection precision deteriorates for thin workpieces
Solution Approach 1:
The cam mechanism introduces rotational motion as an intermediate dimension, converting small linear displacements of the follower into large angular displacements of the cam. This mechanical amplification allows a single sensor to detect small changes in workpiece thickness with high precision, as the angular motion of the target magnifies the effect of small linear position changes.
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
Enables reliable detection of a single workpiece while preventing improper clamping of no workpiece or multiple workpieces, reducing machine damage and downtime, and simplifying the gripper design.
Implementation Method 1
The drive pin and the cam slot are configured to convert linear reciprocal motion of the driving member to rotational motion of the pivotal cam link
Implementation Method 2
The cam driven linkage amplifies travel of the sensing object
Data Source
Figure 1
Figure 2~3C
AI summary
A sensor or switch mechanism (40) is connected to a gripper mechanism (20) and uses a pivotal cam link (60) connected to the driving mechanism (24, 30) of the gripper (20). A cam slot (62) in the cam link (60) is configured to convert linear reciprocal motion of the driving mechanism (24, 30) of the gripper (20) to amplified rotational motion of the pivotal cam link (60). A target (84) on the cam link (60) and a stationary sensor (80) positioned proximate to an arc described by the target (84) on rotation of the cam link (60) allows the sensor or switch mechanism (80) to distinguish between the gripper (20) properly gripping a single workpiece (200) and the gripper (20) improperly gripping no workpiece and/or two or more workpieces.