Counterbore Bolt Fixture for Adjustable Part Positioning
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Solution Overview
Problem
Existing machining technologies face challenges in securely positioning cast or forged parts for machining, as their mating surfaces often do not match three-dimensional models, requiring complex clamps, bump pins, or internally and externally threaded fittings.
Innovation Solution
A machining fixture counterbore bolt fitting system that includes a counterbore hex head bolt, a socket head cap screw, and a jam nut, allowing for adjustable and secure positioning of parts by threading the bolt into a fixture, locking with a jam nut, and securing with a screw threaded into a fixture mating surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex clamps and bump pins are used to position parts for machining, then the part can be securely held, but the device complexity increases
Solution Approach 1:
The fixture system is divided into modular components: a base fixture with threaded bore, a separate adjustable bolt assembly with counterbore, a screw, and a jam nut. Each component serves a specific function, allowing independent adjustment and replacement. The bolt assembly can be detached and repositioned to accommodate different part geometries, eliminating the need for complex integrated clamps and bump pins.
Solution Approach 2:
The fixture employs adjustable and reconfigurable elements rather than fixed structures. The bolt can be threaded to different depths, the jam nut can be positioned at various locations to lock the bolt, and the screw can be adjusted to apply clamping force at different points. This dynamic adjustability allows the same simple fixture to accommodate varying part positions and geometries.
2Adaptability or versatility
If internally and externally threaded fittings are used to adjust part position, then positioning flexibility is achieved, but the device complexity increases
Solution Approach 1:
The bolt assembly serves multiple functions: it provides positioning reference through its threaded engagement with the fixture, enables height adjustment through variable threading depth, and facilitates clamping when combined with the screw and jam nut. The counterbore feature allows the bolt head to bear against the part surface directly or through the screw, providing versatile positioning options without requiring multiple specialized fittings.
Solution Approach 2:
The screw is inserted through the counterbore of the bolt, with the screw head bearing on the bolt head's counterbore surface. The jam nut threads onto the bolt externally while the screw threads into the part internally. This nested arrangement allows compact integration of multiple adjustment mechanisms within a simple structural framework.
3Manufacturing precision
If shims and clamps are used to position and secure parts, then positioning accuracy is achieved, but the ease of operation decreases
Solution Approach 1:
The manual shimming process is replaced by a threaded mechanical adjustment system. The bolt's threaded engagement with the fixture allows precise height and position adjustment through simple rotational motion, eliminating the need to manually insert and adjust multiple shims. The jam nut provides easy mechanical locking of the adjusted position without requiring complex clamp mechanisms.
Data Source
AI summary
A machining fixture counterbore bolt fitting includes a counterbore bolt, (SHCS) screw and jam nut. The counterbore bolt defines an axial bore therethrough, sized to location clearance or sliding fit receive the screw and a counterbore sized to running fit receive a head of the screw and of a depth for the head of the screw to bear on the bottom of the counterbore. The counterbore bolt is threaded through a machining fixture to bring a distal end of the bolt into contact with a surface of a part to be machined, with the axial bore around a screw-threaded bore in a fixture mating surface of the part. The screw is threaded into the screw-threaded bore, holding the part against movement with respect to the fixture. The head of the screw bears on the counterbore bottom, pulling the fixture mating surface against the bolt shaft threaded through the machining fixture.