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  1. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    thanks, what does Wt and Lf mean? okay Lf = lateral force and that will be Wt * slope, whereas Wt is the weight * gravitational constant 9.81 ie weight force I guess?
  2. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    the inertia of the flywheel dosen't come into it because it's allowed to freewheel after the drop of the weight but I do need to take into account the lever masses and there associated inertia's and the mass of the scissors and then the 0.275kg weight itself could you explain for me again...
  3. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    the cam will start to move the peg on the level 1 of the scissor as soon as it drops off of the end of the highest point of the cam. the cam is turning 1revolution/second so will lift the 275gram weight 2ce per rotation of the cam how much torque will be needed to lift the weight if the...
  4. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    I need to modify this need to modify this because I don't want it accelerating the entire 1.26m. Say I want it to accelerate to 2.52m/s very quickly, and then have it move up at that speed untill reaching 1.26m approx 0.5 sec Find acceleration To move the block upwards 1.256637061meters in...
  5. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    my thinking is that if you put a ball in your hand or anything for that matter and move up with constant velocity you are still using effort to move it upwards but not so much that it will leave your hand when you stop moving your hand, okay I get it now
  6. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    I'm going for 0.5 seconds now, the cam will rotate at 2pi rad/s constant rate - and have a constant slope for each half of the cam going from radii 0.324m to 0.45m (difference 0.126m), in pi radains (half a turn). I want this to move the 0.275kg weight up to the desired 1.26m in height in the...
  7. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    so can you clarify what you meant by this please? Don't see why not, except that would result in the load rising at a constant velocity, whereas you want it to rise at an accelerating rate under constant force unless you accelerate the cam rotation rate.
  8. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    fair enough
  9. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    also thought what about a hydraulic press the press with tons of force but they move at a constant speed with no acceleration?
  10. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    this is what has confused me! thanks
  11. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    yeah thats what I was getting at but you said about constant velocity somewhere!
  12. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    anybody??
  13. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    so I'm back for a bit managed to charge laptop, it's not the cable it's the charging port on the laptop have to balance the laptop and charger in some special way for it to charge or the port gets hot and doesn't charge!! have to deal with like this for a bit in limp mode till I can afford a new...
  14. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    so would that be 2.52m/s and that twice for a revoultion
  15. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    so imagine a truck thats moving 5mph and you got in the way of it and pushed against it, it would definately move you although your feet would be slipping on the floor it would be constant velocity and there would be no acceleration or should i say a minor decceleration of the truck but you...
  16. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    its not really a problem if it moves with constant velocity or not but I thought that if I put an unbalanced force that there would have to be acceleration also if the cam is moving 1 turn a second or 2pi then it would'nt be accelerating any way the slope would just lift up the weight at a...
  17. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    this is for half the rotaion of the cam Consider the spiral has an average radius Ravg half way between the minimum and maximum radii Rmin, Rmax. (0.45 +0.324)/2 = 0.387m The spiral length would then be π x Ravg. π * 0.387 = spiral length 1.215796357m Over that length the cam-follower...
  18. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    can I make the spiral to have 2 lobes per revolution and have them both ramp up to 0.126m using archemidian spiral the number I'm getting are good atm
  19. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    going to use this formula and where it says 2pi I will just use pi because the slopes are half rotation
  20. Maglatron

    I want to know all of the maths concerning this scissor mechanism!

    I'd love for someone "to wade in" anyone up for it??? I need to find the slopes of this cam the max diameter is 0.9m and the drops off the lobes is 0.126m if you could provide a method for this it would be very nice, thanks Mr Alec_t please?
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