Pole-Mounted Fastener Tool Lockout Mechanism
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Solution Overview
Problem
Existing fastener driving tools with extended reach mechanisms are prone to inadvertent actuation or misfiring due to excessive pressure, which can result in undesired fastener placement or orientation, and existing solutions like U.S. Pat. No. 7,896,210 add weight and may still experience misfires if the pole assembly is not attached.
Innovation Solution
A fastener actuation system featuring a lockout mechanism with a ball and receptacle that engages the internal rod and trigger sleeve only when the tool is in an acceptable firing position, utilizing a spring to bias the mechanism to a pre-firing position and prevent misfiring by maintaining a gap between the trigger sleeve and the receptacle when the tool is at an unacceptable angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lockout mechanism is added to prevent inadvertent actuation, then reliability is improved, but device complexity increases
Solution Approach 1:
The lockout mechanism is segmented into distinct functional components: a lockout pin with a ball receptacle, a trigger sleeve with a protrusion, and a spring. These segments work independently but interact to achieve the lockout function, allowing each component to be optimized for its specific role while contributing to the overall reliability improvement.
Solution Approach 2:
The ball acts as an intermediary element between the lockout pin and trigger sleeve. When the tool is in an unacceptable orientation, the ball engages the recess in the trigger sleeve to prevent actuation. When properly oriented, the ball falls into the receptacle on the lockout pin, allowing the trigger sleeve to move and enable firing. This intermediary mechanism provides a simple yet effective solution to the reliability-complexity contradiction.
2Productivity
If pressure is applied to extend reach in overhead applications, then productivity is improved, but risk of misfiring increases
Solution Approach 1:
The lockout mechanism applies preliminary anti-action by preventing the trigger sleeve from moving forward when the tool is in an unacceptable orientation. The spring continuously biases the lockout pin to engage the trigger sleeve, creating a pre-existing barrier against inadvertent actuation. This preliminary protective action ensures that even when pressure is applied during overhead applications, the firing sequence cannot occur unless the proper orientation is achieved first.
3Ease of operation
If the tool allows firing in any orientation, then ease of operation is improved, but harmful effects increase due to misfiring
Solution Approach 1:
The lockout mechanism introduces dynamic orientation-dependent engagement. The ball and recess geometry is designed so that the ball only falls into the receptacle when the tool is held at the correct angle. This dynamic behavior automatically adapts to the operator's orientation, allowing easy operation when proper technique is used while preventing harmful misfiring when the tool is held incorrectly. The mechanism transitions between locked and unlocked states based on orientation, providing both safety and operational flexibility.
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 system effectively prevents unintended firing by ensuring the trigger sleeve does not advance unless the tool is oriented correctly, reducing the likelihood of misfires and maintaining tool stability without adding unnecessary weight.
Implementation Method 1
utilizing a spring to bias the mechanism to a pre-firing position
Data Source
AI summary
A fastener actuation system for driving fasteners into a work surface separated a significant distance from a user, the system comprising a fastener actuation tool coupled to a pole assembly, the assembly including a lockout mechanism disposed within the tool. The tool may have a firing pin assembly configured such that depression of the barrel assembly against the work surface loads a firing pin into a ready-to-fire position. In addition, the tool may have a trigger sleeve slidable within the tool housing and having a ramp surface such that forward motion of the trigger sleeve may cause a trigger sear to move along the ramp surface until a point where the sear disengages and the firing pin fires. The lockout mechanism may include a ball and a receptacle, where the receptacle receives the ball if the tool is in an acceptable orientation and does not receive the ball otherwise.