kickback brake CIRCULAR SAW WITH SAFETY FEATURE TO PREVENT INJURY - PowerPoint PPT Presentation

kickback brake CIRCULAR SAW WITH SAFETY FEATURE TO PREVENT INJURY FROM KICKBACK

Cause of circular saw injuries slip 17% kickback unknown 9% 44% contact with blade 30%

Product Vision Circular saw with integrated kickback prevention features Braking 
 mechanism Anti-kick 
 mechanism

How does the saw “know” kickback is happening? Customer Need Attributes Engineering Specs Detect a voltage drop greater Reliably detect a kickback event Fault detection than 4V.

≈ 4V drop Test: simulating kickback to characterize voltage drop

Voltage Drop Data

How far does the saw move during kickback? Customer Need Attributes Engineering Specs Kickback vertical distance less Limit translational motion of saw Range of motion than 5cm to keep blade inside during kickback material

Skate Mechanism Prevents tool from flying Skate out of the material

How can we limit severity of injury? Customer Need Attributes Engineering Specs Stop blade rotation during a Blade rotational Stopping time less than 40ms kickback velocity

Caliper Brake Release pin 
 and line RELEASE PIN ACTUATES SPRING Saw Blade Compression Spring Brake line Caliper Brake

How might this safety feature be unobtrusive? Customer Need Attributes Engineering Specs Safety mechanism located outside of normal cutting path. Operates normally under non- Usability kickback conditions Weight and size of tool is within 20% of normal size.

Usability Braking integrated into existing tool features Clutch braking on rotor Must be retractable instead of in the path of blade for plunge cuts

Target Market First-time User Amateur User Experienced User Frequent User Professional • Targeting makerspaces (amateur — experienced users) to reduce concerns about injury liability • Targeting professionals for workplace injury prevention • Price estimate of $300 - $350 for a saw with kickback brake

appendix

Product Contract Customer Need Attributes Engineering Specs Limit translational motion of saw Kickback vertical distance less than Range of motion during kickback 5cm to keep blade inside material Safety mechanism located outside of normal cutting path. Operates normally under non- Usability kickback conditions Weight and size of tool is within 20% of normal size. Stop blade rotation during a Blade rotational Stopping time less than 40ms kickback velocity Detect a voltage drop greater than Reliably detect a kickback event Fault detection 4V.