Quick Change Arbor With Drive Pins Prevents Hole Saw Thread Locking
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Solution Overview
Problem
Small diameter hole saws with outer diameters less than 1¼ inches often lock up on arbor threads during use, making them difficult to remove and potentially causing damage to the arbor and hole saw, and existing solutions fail to provide a universal arbor compatible with various sizes due to varying wrench flat widths and lack of drive pins.
Innovation Solution
An arbor design featuring a drive member with axially movable drive pins that engage with drive pin recesses on the hole cutter, allowing for quick attachment and detachment, and a threaded connection that aligns drive pins with recesses to prevent locking, enabling the arbor to accommodate multiple sizes of small diameter hole cutters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If small diameter hole saws are driven by threading onto the arbor's threaded end portion, then the hole saw can be securely attached to the arbor, but the hole saw may lock up on the threads during use making removal difficult or impossible
Solution Approach 1:
The attachment system is divided into two independent functions: threaded engagement for axial securing and drive pin engagement for rotational driving. The drive pin plate with movable drive pins separates the driving function from the threaded connection, allowing the hole saw to be driven off the drive pins rather than the threads, preventing lock-up and facilitating easy removal.
Solution Approach 2:
The drive pin plate acts as an intermediary component between the arbor and the hole saw. It transfers rotational motion from the arbor to the hole saw through drive pins that engage with drive pin apertures in the hole saw, while the threaded connection provides only axial positioning, eliminating the locking problem.
2Device complexity
If conventional arbors for small diameter hole saws do not include drive pins, then the arbor structure remains simple, but the hole saw cannot be quickly attached or detached and may lock up on threads
Solution Approach 1:
The drive pin plate is designed to be movable relative to the arbor body along the axial direction. The drive pins can be moved into engagement with the drive pin apertures of the hole saw and then locked in position, allowing quick attachment and detachment without threading operations, significantly reducing the time required for changing hole saws.
3Ease of manufacture
If arbors are designed without drive pin apertures and drive pins, then manufacturing is simpler, but hole saws cannot be driven off the drive pins to prevent locking and damage
Solution Approach 1:
The driving function is segmented from the threaded connection. Drive pins on the movable drive pin plate provide the rotational driving force, while the threaded end portion provides only axial positioning. This separation ensures that the threads are not subjected to rotational stresses that cause locking and damage, improving reliability.
4Ease of operation
If small diameter hole saws use wrench flats for removal, then users can attempt to unlock the saws, but the threads can still be stripped and damaged beyond repair
Solution Approach 1:
The drive pin mechanism extracts the rotational driving function from the threaded connection. By driving the hole saw off the drive pins rather than the threads, the threads are preserved from damage, and removal can be achieved by simply moving the drive pin plate without applying damaging forces to the threaded interface.
Data Source
AI summary
An arbor is provided for small diameter quick change and standard hole cutters. Each hole cutter defines an outer diameter of less than 1¼ inches, a central aperture and at least one drive pin recess. The arbor comprises an arbor body including an end portion engageable within the central aperture, and a drive member having at least one drive pin for engaging a corresponding drive pin recess of the hole cutter for rotatably driving the hole cutter.