Semi-Concentric Drive Chains for Constant Velocity Palletizer Sweep
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Solution Overview
Problem
Existing sweep systems in material handling systems, particularly palletizers, face challenges with reciprocating arms that experience extreme inertial forces and unwanted momentum when traveling around corners due to single chain-type drive systems, leading to increased wear and complex control requirements.
Innovation Solution
A row sweep system utilizing a pair of continuous drive members, such as inner and outer drive chain loops arranged semi-concentrically, to maintain a substantially constant velocity of the sweep pusher arm while traveling around a station, with a sweep arm assembly supported by both drive chains to manage orientation and maintain velocity through corners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single chain-type drive system is used to drive the sweep arm, then the control is simplified and the home position return time is reduced, but the sweep arm experiences extreme inertial forces and unwanted momentum when traveling through corners, causing increased wear and whipping characteristics
Solution Approach 1:
The patent divides the single drive chain into two separate drive chains (first drive chain and second drive chain) that operate independently. Each drive chain has its own sprockets and tensioners, allowing the sweep arm to be driven at a substantially constant velocity without the acceleration spikes and inertial forces that occur with a single chain system. This segmentation resolves the contradiction by maintaining control simplicity while eliminating the harmful inertial effects.
Solution Approach 2:
The patent introduces intermediate elements including idler sprockets, tensioners, and a belt or chain connection between the two drive chains. These intermediary components mediate the power transmission to maintain constant velocity while reducing the harmful inertial forces. The intermediate elements allow the drive system to achieve smooth, controlled motion without the whipping characteristics and excessive wear associated with single-chain systems.
2Loss of time
If a single chain-type drive system is used, then the sweep arm can be driven in a single direction to return to home position, but the sweep arm must travel distances that increase per equal time interval when passing through corners, causing substantial acceleration spikes
Solution Approach 1:
The patent segments the drive system into two independent drive chains that can each maintain constant velocity. This segmentation allows the sweep arm to travel through corners at a substantially constant speed without the acceleration spikes that occur with a single chain system, where the arm must travel increasing distances per equal time interval when passing through corners.
Solution Approach 2:
The patent changes the operational parameters of the drive system by using two drive chains instead of one, allowing the sweep arm to maintain a substantially constant velocity throughout its movement. This parameter change eliminates the acceleration spikes and maintains consistent speed, resolving the contradiction between return time and acceleration.
3Productivity
If reciprocating arms are used to push products, then the sweep system can push products in one direction and return to home position, but the system takes time to reciprocate back and forth, limiting the speed at which product can be moved
Solution Approach 1:
The patent uses two separate drive chains that operate simultaneously to drive the sweep arm in a single direction without the time-consuming reciprocation required by single-chain systems. This segmentation allows the sweep arm to maintain constant velocity throughout the movement, eliminating the reciprocation time and increasing product movement speed.
Solution Approach 2:
The patent implements continuous useful action by using two drive chains that maintain constant velocity throughout the sweep arm's movement. This eliminates the reciprocating motion and associated downtime, allowing the sweep arm to continuously push products at high speed without the time loss inherent in reciprocating systems.
Data Source
AI summary
A row sweep system is configured to allow a sweep pusher arm such as a roller to travel around a station such as a row-forming station of a palletizer at a substantially constant velocity. The row sweep system may include a pair of semi-concentrically continuous drive members such as inner and outer drive chain loops that are connected through inner and outer pivot arrangements to the sweep pusher arm. The inner pivot arrangement may define a slide pivot that allows for varying an effective length of a driven arm defined between the inner and outer pivot arrangements to accommodate movement of the sweep pusher arm through a corner while maintaining a substantially constant velocity.