Hammer Drill Torque Clutch Control for Jamming Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hammer drills often jam on reinforcing bars in reinforced concrete, causing the drill to become stuck and unable to be removed due to excessive clamping effect, which increases the chiseling action and makes disengagement difficult.
Innovation Solution
A control method that monitors the torque clutch and reduces the impact power to less than 10% of the nominal when the torque clutch is triggered, while maintaining rotation and switching off the percussion mechanism to prevent further clamping, and resumes normal operation when the drill bit disengages, allowing for pulsed torque transmission and reduced chiseling effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hammer drill operates with full impact power to drill through reinforced concrete, then drilling capability is improved, but the drill may jam on reinforcing bars causing excessive clamping effect
Solution Approach 1:
The control method implements periodic action by detecting torque clutch triggering and responding with impact power reduction cycles. When the torque clutch triggers (indicating potential jamming), the impact power is reduced to less than 10% of nominal power for a specific duration, then restored. This periodic modulation of impact power prevents sustained clamping that causes jamming while maintaining drilling capability during normal operation.
Solution Approach 2:
The invention applies parameter changes by dynamically adjusting the impact power parameter based on torque clutch status. The impact power is changed from nominal level to reduced level (<10% of nominal) when jamming is detected, and the duration of this parameter change is controlled to allow drill disengagement. This dynamic parameter adjustment resolves the contradiction between maintaining high power for drilling and reducing power to prevent jamming.
2Ease of operation
If the torque clutch is triggered and impact power is reduced to less than 10% of nominal, then the clamping effect is reduced allowing drill disengagement, but the drilling productivity decreases
Solution Approach 1:
The control method uses periodic action to temporarily reduce impact power only when torque clutch triggering indicates jamming, rather than continuously reducing power. The impact power is restored to nominal level when the torque clutch releases, maintaining high drilling productivity during normal operation while enabling drill disengagement when needed.
Solution Approach 2:
The invention applies partial action by reducing impact power to less than 10% of nominal (rather than completely shutting it off) during torque clutch triggering. This partial reduction is sufficient to allow drill disengagement by reducing the clamping effect, while the brief duration and limited magnitude of reduction minimize the impact on overall drilling productivity.
3Object-affected harmful factors
If the percussion mechanism is switched off during torque clutch triggering, then the clamping effect is reduced, but the chiseling action is lost
Solution Approach 1:
The control method applies parameter changes by adjusting the impact power parameter to less than 10% of nominal power instead of completely switching off the percussion mechanism. This partial parameter adjustment reduces the clamping effect sufficiently to allow drill disengagement while maintaining enough chiseling action to preserve the ability to break up concrete and remove debris from the hole.
Data Source
Figure 1
AI summary
The control method for a hammer drill (1) provides the following steps. In basic operation, the motor (5) rotates at an operating speed for drill bit operation to rotatingly drive the tool receptacle (2) and to drive the striking mechanism (6) with a nominal striking power. The torque coupling (21) is monitored by a sensor (26). If the torque coupling (21) is released, then the striking power of the striking mechanism (6) is reduced to below 10% of the nominal strike power during a release of the torque coupling (21), and the torque coupling (21) is rotatingly driven. When the release of the torque coupling (21) ends, the striking power of the striking mechanism (6) is increased to the nominal striking power and the torque coupling (21) is driven at the operating speed for drill bit operation.