Windscreen Wiper Arm Locking Mechanism Prevents Detachment
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Solution Overview
Problem
Existing windscreen wiper arms allow pivot movement beyond a maximum angle, leading to the arm member becoming loose from the mounting head, causing detachment and negative consequences.
Innovation Solution
The integration of locking means on the pivot pin, which forms an integral part of the mounting head, with a protrusion that locks into recesses on the U-shaped arm member, preventing disengagement in the elevated position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the arm member is allowed to pivot freely beyond a maximum angle for easy service access, then the ease of operation is improved, but the reliability deteriorates as the arm member may detach from the mounting head
Solution Approach 1:
The connection between the arm member and mounting head is segmented into discrete locking positions using the protrusion-feature mechanism. The protrusion on the pivot pin engages with corresponding features on the arm member to create distinct stable positions (wiping position and elevated position), preventing continuous unintended movement while allowing controlled pivoting for service access.
Solution Approach 2:
The protrusion on the pivot pin acts as a preliminary anti-action mechanism by preemptively preventing the arm member from pivoting beyond the maximum intended angle. This geometric constraint is built into the connection structure itself, counteracting any forces that might cause over-pivoting and potential detachment before such detachment can occur.
2Reliability
If locking means are added to prevent arm member detachment, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The locking means are merged with the existing pivot pin structure. The protrusion is formed directly on the pivot pin itself, combining the pivoting function and the locking function into a single integrated component. This eliminates the need for separate locking mechanisms while maintaining connection reliability.
Solution Approach 2:
The geometric features (protrusion and corresponding recesses) on the pivot pin and arm member create a self-locking mechanism. The protrusion automatically engages with the arm member features during assembly and service operations, providing passive mechanical locking without requiring additional actuators, sensors, or control systems.
3Manufacturing precision
If the pivot pin is made as an integral part of the mounting head, then the manufacturing precision is improved, but the ease of manufacture deteriorates due to integrated production requirements
Solution Approach 1:
The protrusion features are pre-formed during the mounting head manufacturing process (such as injection molding or casting), integrating the locking features into the base structure. This preliminary incorporation of locking features simplifies subsequent assembly operations while ensuring precise alignment between the pivot pin and arm member.
Data Source
Figure 1~2
Figure 3~4B
Figure 5A~5D
AI summary
A windscreen wiper arm (1), particularly for automobiles, comprising a mounting head (2) mountable on a drive shaft (3) and an arm member (4) pivotally connected to the mounting head (2) by means of a pivot pin (5), and wherein the arm member (4) can be pivoted between a wiping position, wherein the arm member (4) extends parallel to a windscreen to be wiped, and an elevated position, wherein the arm member (4) and/or a windscreen wiper blade to be attached thereto can be repaired or replaced, characterized in that said windscreen wiper arm (4) is provided with locking means (17,18) arranged to lock said arm member (4) onto said pivot pin (5) in order to prevent said arm member (4) from disengaging from said pivot pin (5) in the elevated position of said arm member (4).