Watch Striking Mechanism Latch Reduces Hammer Rebound
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Solution Overview
Problem
Existing watch striking mechanisms experience significant kinetic energy loss and rebound issues due to counter-springs, which reduce the acoustic level of striking and require complex adaptations to prevent rebound.
Innovation Solution
A blocking device with a latch mechanism that locks the hammer after the first strike, using a hook to engage a notch on the hammer's periphery, minimizing the counter-spring's force needed to return the hammer to rest, thus preventing rebound and maintaining acoustic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a counter-spring is used to hold the hammer away from the gong and return it to resting position, then the hammer can be reset after striking, but significant kinetic energy is lost during the strike
Solution Approach 1:
The latch is pre-positioned to engage with the hammer immediately after the strike, preventing rebound before it can occur. This preliminary locking action eliminates the need for the counter-spring to dissipate kinetic energy through prolonged deceleration, thereby reducing energy loss while maintaining the hammer's reset capability
2Reliability
If the counter-spring force is increased to prevent hammer rebound, then the hammer returns reliably to resting position, but the acoustic level of the strike is reduced
Solution Approach 1:
The latch engages with the hammer periphery immediately after the strike impact, preventing rebound before it can occur. This eliminates the need for a strong counter-spring force, allowing the use of a weaker spring that does not interfere with the hammer's striking velocity and acoustic output, while still ensuring reliable return to the resting position
3Productivity
If the latch engages the hammer periphery with a delay after the strike, then the hammer can strike the gong freely, but the hammer rebounds against the gong
Solution Approach 1:
The latch is designed to engage with the hammer periphery with a controlled delay that allows the strike to complete, then immediately locks the hammer to prevent rebound. This timing optimization ensures both striking efficiency and rebound prevention, as the latch is positioned to engage just after the hammer impacts the gong but before rebound can occur
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 solution effectively prevents hammer rebound and reduces kinetic energy loss, allowing for a more efficient striking mechanism with minimal counter-spring force, enhancing the acoustic level of the watch's striking sound.
Implementation Method 1
a damping counter-spring (5) arranged to repel and hold the hammer (4) at a distance from the gong (2) in a resting position
Implementation Method 2
a drive spring (6) arranged to drive the hammer (4) against the gong (2) in a striking mode
Data Source
Figure 1
Figure 2a~2b
Figure 2c
AI summary
The striking mechanism (1) of a watch includes a gong (2), which is connected to a gong holder (3), a hammer (4) for striking the gong (2) at predetermined times, a damping counter-spring (5) for keeping the hammer away from the gong (2) in a rest position, and a hammer drive spring (6), which includes a fixed end and a free-moving end. The drive spring is capable of being wound to drive the rotating hammer (4) by means of a pin (10) against the gong (2) in a striking position to produce an acoustic sound. The striking mechanism includes a locking device, which is provided with at least one rotating lock (8). This lock (8) includes a first arm (8a) provided with a hook (28) for engaging with a notch (15) of the hammer (4) to lock it in a rest position.The hook of the first arm of the lock (8) can be moved away from the hammer in striking mode when the drive spring (6) is cocked and an end portion of a lock spring (7) pushes a second arm (8b) of the lock away from the periphery of the hammer. The locking device is arranged to lock the hammer after a single strike of the hammer against the gong in striking mode.