Download - Assisted Bench Press Machine JARRED MORALES JUNKUN MA SPRING 2014 SOUTHEASTERN LOUISIANA UNIVERSITY
Assisted Bench Press MachineJARRED MORALES
JUNKUN MA
SPRING 2014
SOUTHEASTERN LOUISIANA UNIVERSITY
Negative Reps
Intensify workouts
Overload muscle groups
Control the tempo of the repetition for a 3-5 seconds rep count
25% more than you can lift
Eccentric phase causes muscle fiber damage
Assembly
Adjustable flat bench
45 pound barbell
two single acting cylinders
Front flange mount
U-bolts
Adjustable flat bench
Middle notch is the neutral position
The lower notch brings the bench closer to the floor
Accommodate for different arm lengths
Stroke Length
Laying forward grip reach
Drillis and Contini
Body segment lengths expressed as a fraction of body height H.
5’8’’(.438)=30in
Vary due to grip on the bar
Continuity Equation
Steady flow in a pipeline means weight flow rate is the same for all locations
Single inlet/outlet, no fluid added or withdrawn— Qi=Qe
Q=VA
Flow Characteristics
Nomographic chart
Volume Flow Rate
Required pump volume flow rate
Fluid volume swept out by the piston traveling through its stroke over a period of time
2in diameter
Schematic
Single Acting Cylinder
One port
Pressure from the fluid forces piston up
Force from weight pushes piston down
Pressure
Pmin=
hydraulic cylinder cushion
Prevents slamming from end to end
Plunger decelerates piston at the end of extension and retraction strokes
Creates a higher pressure
Cushion Equations
a cushion with a .75in height and 1in diameter
P
P
Directional Flow Control Valve
three way, two position, spring offset, pilot operated, directional control valve normally open
Pressure compensated flow control valve
The breaks
Maintain an essential constant flow rate with variations in inlet and load pressures
A spool is held by a set to set psi spring keeping it normally open
The type of pump
Requires a low pressure with a low volume flow rate
Ignoring OHP
Type of oil
Pressure Regulator
Connected between the pump and the DCV
Pressure changes due to variation in amount of weight being lifted
Can be adjusted to change amount of assistance
Check Valve
Between the pressure regulator and directional control valve
Prevents flow from flowing back to the regulator
Accumulator
Nitrogen filled bladder
Elastic barrier is between oil and gas
Safety mechanism
The volume decreasing in gas, causes an increase in stored energy
Reservoir
Storage space for excess fluid
Way of filtering
Metal chips, sludge, and water will be removed from oil
High enough oil level to prevent whirlpool effect
Surface area for heat dissipation and air space for thermal expansion
Conclusion/Future Design
Replaces need for assistance and most of the bench press assembly
Monitored the rate at which the cylinder descends, using a pressure compensated fcv
Applicable for different ranges of weight and people
Could have used a double acting cylinder with a four way, two direction control valve and eliminated the need of the weights
Thank you
Dr. Junkun Ma
Mr. James Stutts