Tunneled Push Block for Table Saw Blade Straddling
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Solution Overview
Problem
Existing woodworking accessories for table saws do not effectively restrain the workpiece on both sides of the saw blade, leading to potential kick-back and damage, and often require the operator to use an unprotected hand to maintain control during cutting.
Innovation Solution
A tunneled push block with a guide system that straddles the saw blade, featuring adjustable tunnels and indicators to ensure safe positioning regardless of the fence position, allowing the workpiece to be securely held on both sides of the blade without being cut and without damaging the push block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple push stick is used to urge stock material past the saw blade, then the operator's fingers are protected at a safe distance, but the tool can only apply downward force against the trailing edge portion of the work piece, which is inadequate to hold the stock material down and may cause kick-back
Solution Approach 1:
The push block is divided into multiple functional segments: a first engagement surface for applying downward force on the leading edge, a second engagement surface for applying downward force on the trailing edge, and a handle portion. This segmentation allows simultaneous control of both edges of the stock material, preventing kick-back while maintaining operator safety.
2Reliability
If a push stick engages only the rear edge of the work piece, then the operator's hand is protected, but the leading edge portion of a long piece of stock material is not restrained, creating potential kick-back danger
Solution Approach 1:
The push block provides separate engagement surfaces for both the leading edge and trailing edge of the stock material. The first engagement surface restrains the leading edge while the second engagement surface maintains control of the trailing edge, eliminating kick-back risks from unrestrained portions while keeping the operator's hand protected by the handle design.
3Ease of operation
If a narrow hand guard is positioned against the guide fence, then it can be used for removing a small width of material, but it engages the stock material only near its rear edge and is ineffective in restraining the leading edge portion
Solution Approach 1:
The push block's broad engagement surfaces allow it to effectively engage both the leading edge and trailing edge of wide stock material, unlike narrow hand guards. The first engagement surface specifically addresses the leading edge restraint problem while the second engagement surface maintains precise control near the fence, enabling effective operation with wider work pieces.
4Reliability
If screws are used to engage the work piece along an extended length, then operator's hands are kept away from the saw blade, but undesirable damage is caused to the work piece
Solution Approach 1:
The push block uses a sacrificial wooden construction that can be replaced if damaged, rather than using screws that permanently damage the work piece. The block engages the stock material along its entire length through friction and mechanical contact, keeping hands safe without causing harmful modifications to the work piece.
Data Source
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AI summary
An apparatus (100), including: a push block (100) including: a first side (120) and a second side (122), each configured to abut and slide along a fence of the table saw; and a bottom (124) including a first tunnel (130) and a second tunnel (132) and an immovable dividing wall (134) therebetween. When the first side abuts the fence the first tunnel is configured to straddle a blade throughout a first tunnel first range of fence positions (R12), and the second tunnel is configured to straddle the blade throughout a second tunnel first range of fence positions (R34). When the second side abuts the fence the first tunnel is configured to straddle the blade throughout a first tunnel second range of fence positions (R45), and the second tunnel is configured to straddle the blade throughout a second tunnel second range of fence positions (R23).