HYDRAULIC UNSCREWING DEVICE Calculations/Specifications
B. Control Cam Calculation
FULL OPEN POSITION ANTI-ROTATIONAL STRIPPER PLATE "OR BUMP" MOVES UP AT A FASTER RATE DUE TO ANGLE BETA AND SEPARATES FROM THE MAIN STRIPPER PLATE MOVING AT RATE DUE TO ANGLE ALPHA
O.D. OF THREADS (MAJOR THREAD DIA OF THE CORE) THREAD LEAD
CLOSED POSITION BOTH STRIPPER PLATES MOVE UP TOGETHER AT THE SAME RATE DUE TO ANGLE ALPHA
THREAD HT.
CLOSED
ANTI-ROTATIONAL STRIPPER PLATE MAIN STRIPPER PLATE STRIPPER PLATES PUSHED UP BY CAM ANGLES
BUMP LIFT
ANTI-ROTATIONAL STRIPPER PLATE
ß BETA
ALPHA
CAM
MAIN STRIPPER PLATE
OPEN
CAM
THREADS GET ROTATED
MOVING HYDRAULIC CYLINDER PUSHES CAM AND RACK
SPUR GEAR
MOVES MAIN STRIPPER PLATE
B
BUMP
PITCH DIA.
STATIONARY HYDRAULIC CYLINDER BODY
RACK
A
STROKE
C. Unscrewing Force These figures should only be used as a guideline, as many other factors will affect the calculation (material, variation of dimensions, material shrinkage, core surface area, temperature, lubricants, friction, etc.). f) Residual Pressure (PSI) = 1/100 of maximum injection pressure g) Effective core surface area (Square Inches or in 2 , Outer Core Cylinder Shell) Flat end of threaded core neglected, x 2 value for 45° triangle thread shape = major thread dia. of the core x π x thread height x 2 h) Unscrewing torque (in-lb f ) = Residual Pressure x Effective core surface area x major thread radius of core i) Unscrewing force rack (lb f ) Unscrewing Torque X number of cavities = Gear pitch radius k) Hydraulic force (lb f ) NOTE: x 1.5 is 50% Safety Factor, if x 1.0 there would be no safety factor. = Unscrewing Force x 1.5
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