Electro-mechanical Safety Lift for Self-spotting Bench Press Machine

Proposing Students:Chris Potts (EE) & Lane Caffaro (ME)

Project Supervisors:Professor John Spinelli &Professor Jennifer Currey

Motivation

Everyone wants the perfect body New training programs, dietary supplements, and workout

machines

Maximize potential muscle growth Working muscles until failure

Dangerous without a spotter Work until lifter doubts he/she can lift the bar No human spotter Still augment muscle capacity with safety as a priority

Data Subjects

Inexperienced lifter (53 years old) Never lifts

Middle-aged male (41 years old) Lifts approximately (1 time per week)

Male students (both 22 years old) Lifts regularly (3-4 times per week)

Female students (18 & 20 years old) Lifts regularly (3-4 times per week)

Position

Female (18) – 95 lbs. (no fail)

Male (22) – 185 lbs. (failure)

Velocity

Female (18) – 95 lbs. (no fail)

Male (22) – 185 lbs. (failure)

Acceleration

Female (18) – 95 lbs. (no fail)

Male (22) – 185 lbs. (failure)

Parameters

Vertical range: 1.2 ft, 2 ft.

Horizontal range: TBD (≈ 6 inches)

Velocity range: ± 1 m/s

Acceleration range: ± 4 m/s2

Weight range: 65 lbs., 185 lbs.

Activation Options

Automatic Lifting when unnecessary

Foot pedal Inconvenience

Voice activated Too much interference

Manual switch on bar Obtrusive grip

Control matrix Ease of use Safety Lifting at proper time Ease of installment Ease of operation Unobtrusive Cost

Design Requirements

Wireless push switch Activates the system

Motors Move up at a rate of 1 m/s

Capable of lifting up to 300 lbs. Switch placed in the bar for comfortable grip Output device

Repetitions, minimums/maximums Maximum time to rack bar: 2 s Maximum time to stop downward motion of bar after

engagement: 0.5 s

Hydraulic Design

Hydraulic Design

Hydraulic Design

Block Diagram

Limitations

Assistance of hydraulics Ability to lift up to 300 lbs. at a velocity of 1 m/s

Placing the switch in the bar to avoid obtrusive grip

Only normal wide-grip bench is applicable

Goals

Phase 1: Activating the system

Phase 2: Lifting the bar safely

Phase 3: Racking the bar safely Output device

Timeline

Fall term: IEF proposal (week 3) Gather data

Position, velocity, acceleration (week 6)

Horizontal movement (week 9)

Angle of Bar (week 9) Finalize design (week 8) Design report (week 10) Order parts (week 10)

Winter break: Complete phase 1

Winter term: Complete phase 2 (week 2) Complete phase 3 (week 5) Working prototype (week 6)

Conclusion

Working prototype of a Self-Spotting Bench Press Machine

Even without a human spotter he/she can work muscles until failure

Safety is a priority

Questions