Paver Dowel Bar Feeder with Unidirectional Chain
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Solution Overview
Problem
Existing slipform pavers face delays in dowel bar insertion, which slows down concrete laying speed and increases costs due to manual loading of dowel bars into holding cups, requiring the transport chains to stop and move reciprocally.
Innovation Solution
A magazine-based dowel bar feeder system with unidirectional chains and L-shaped cups allows dowel bars to gravitationally drop into holding cups, eliminating the need for manual loading and enabling continuous operation, allowing for higher insertion rates and maintaining optimal paving speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual loading of dowel bars into holding cups is used, then the transport chains can be stopped and loaded, but the concrete laying speed decreases and productivity is reduced
Solution Approach 1:
Dowel bars are pre-loaded into holding cups while the transport chain is stationary at a loading station before the paver begins movement. This preliminary loading allows the chain to be fully stocked with dowel bars prior to operation, eliminating the need to stop during concrete laying and maintaining continuous high-speed operation.
Solution Approach 2:
The system uses gravity-fed dowel bar delivery where dowel bars automatically feed from a magazine into the holding cups on the moving chain without requiring manual intervention during operation. The chain continuously circulates and self-replenishes at the loading station, enabling automatic operation that maintains paving speed.
2Ease of operation
If reciprocating transport chains are used to move dowel bars, then dowel bars can be delivered to insertion positions, but the chains must stop and reverse direction reducing operational efficiency
Solution Approach 1:
The transport chain transitions from a reciprocating motion (stop-and-reverse) to continuous unidirectional rotation. The chain continuously circulates in one direction, constantly presenting holding cups to the dowel bar delivery mechanism and then to the insertion position, eliminating all stopping and reversing operations.
Solution Approach 2:
The transport chain operates continuously without interruption, constantly circulating holding cups through the loading zone and the insertion zone. This continuous circulation ensures that dowel bar delivery and insertion operations can proceed without pause, maintaining the high speed required for efficient concrete laying.
3Productivity
If high insertion rates are required to maintain 15 feet per minute paving speed, then the dowel bar insertion process must be completed in less than one minute, but manual loading cannot achieve this rate
Solution Approach 1:
The system employs automatic gravity-fed delivery where dowel bars automatically feed from a magazine into holding cups on the moving chain without manual intervention. This automation enables rapid sequential loading of multiple dowel bars, achieving the high insertion rates necessary to complete 12-34 dowel bars in under one minute and maintain 15 feet per minute paving speed.
Solution Approach 2:
Multiple holding cups are pre-loaded with dowel bars in sequence while the chain is stationary or moving slowly at the loading station. This batch pre-loading ensures that when the chain moves to the insertion position, all necessary dowel bars are already in place for immediate insertion, maximizing the insertion rate.
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 significantly increases dowel bar insertion speed, enabling slipform pavers to maintain desired concrete laying speeds of up to 15 feet per minute without reducing machine speed, thus reducing overall concrete laying costs.
Implementation Method 1
the dowel bars gravitationally drop from the magazine towards the cups at the loading station
Data Source
AI summary
A paver for laying down a strip of concrete and inserting therein dowel bars parallel to the strip. A dowel bar inserter orients the bars and places them into the concrete. A pair of transport chains transverse to the travel direction extends across a width of the inserter. Pairs of generally L-shaped opposing cups hold the bars so that they can drop downwardly from the cups towards the strip. The chains move in a single direction. A dowel bar holding magazine, above the chains, stores bars, and gravitationally moves the bars towards the chains for pick-up by cups as the chains move the cups past a bar loading station. Elastic bands extend about a bar engaging surface defined by a wheel and resiliently bias the bars moving along the chain turn-around section against the wheel.