Horizontal Hinge Linkage for Power Miter Saw Deflection Control
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Solution Overview
Problem
Conventional sliding miter saws with linear guide assemblies are expensive, prone to damage from dirt and grit, and have a large footprint due to the need for space behind the saw blade, limiting their placement near walls and suffering from deflection issues that affect cut quality.
Innovation Solution
A power miter saw utilizing a horizontal hinge linkage instead of elongated rods and bushings, providing increased stiffness and reduced sensitivity to dirt and grit, with a simpler construction that maintains the saw blade and motor assembly's elevation during movement, allowing for dual bevel operations and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional linear guide assemblies with rods and bushings are used, then the saw blade can move along a linear path, but the assembly is expensive and susceptible to damage from dirt and grit
Solution Approach 1:
The patent extracts the vulnerable rod and bushing components from the linear guide assembly and replaces them with a hinge linkage mechanism. The hinge linkage eliminates the need for exposed rods and bushings that are susceptible to dirt and grit infiltration, thereby improving reliability while reducing structural complexity
Solution Approach 2:
Instead of using a traditional rod-bushing linear guide where rods slide through bushings, the patent inverts the approach by using a hinge linkage where links rotate about pivot points. This inversion fundamentally changes the mechanical principle from sliding contact to rotational pivoting, making the system more resistant to contamination
2Area of stationary object
If elongated rods and bushings are used for linear guidance, then the saw blade can be moved, but the footprint is large due to space requirements behind the blade
Solution Approach 1:
The patent repositions the linear guidance mechanism from an extended rearward configuration to a compact configuration integrated within the saw's structural framework. The hinge linkage allows the blade assembly to move along a linear path while occupying minimal space behind the blade, effectively utilizing the vertical and lateral dimensions rather than requiring extensive rearward space
3Manufacturing precision
If recirculating ball bearings and hardened steel rods are used, then minimum play and deflection are achieved, but the construction is expensive
Solution Approach 1:
The patent replaces expensive recirculating ball bearings and hardened steel rods with a simpler hinge linkage mechanism using pivot points and links. While individual hinge components may be less durable than precision ball bearings, the overall system achieves sufficient precision at a much lower cost, and the components can be easily replaced if needed
Solution Approach 2:
The patent changes the fundamental operating parameters of the linear guide by transitioning from high-precision sliding contact with ball bearings to a rotational pivot mechanism. This parameter change allows the system to achieve acceptable play and deflection levels through the geometric constraints of the hinge linkage rather than relying on precision bearing surfaces
Data Source
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AI summary
A glide movement controller (310) for use with a hinge connection (224) that includes a shaft (230), as well as a hinge connection (224) and a power saw (10) including such a controller (310). The glide movement controller (310) includes a generally U-shaped controller body (312) configured to move towards the shaft (230) in a first direction such that resistance upon the shaft (230) is increased and away from the shaft (230) in a second direction such that resistance upon the shaft (230) is decreased; a pair of apertures (324) extending through the controller body (310); and an interior bearing surface (316) defined on the controller body. The interior bearing surface (316) is configured and arranged to face the shaft (230). In certain embodiments, at least a portion of the interior bearing surface (316) is located between the apertures (324).