Sovella workbench V-2.0 (update 12-22)

grabcad

Sovella workbench V-2.0 Shaft gear screw mechanism, with torsion coil spring assist with adjustable spring pre-load for different loads. Vertical screws in end legs. All gears are the same part for easy production. Reversible ratcheting spring pre-load adjustment similar to cable winch mechanism. Hand crank handle for height adjustment can be set at different lengths for different leverage and speed. For users with less or more strength and for different loads. Quick adjust over-center latch. Hand crank grip is long enough for two hands, for two arm use, for users with less strength. Hand crank handle could fold out of the way, or flip backwards for storage. Update 12-22-2011 The spring pre-load mechanism might be even better if it was driven by a worm gear. It is self locking and has a smooth rotation in both directions. Compared to a ratcheting winch which needs further mechanics to lock and uses a time consuming back and forth motion with 1 notch at a time in the lowering direction. after looking at what has been conceived and presented up to this point, this may be the workbench that I will develop further. With the two conditions of variable load and variable user strength this design accommodates both with variable spring assist and variable manual crank ratio. UPDATE 1/5/2012. After doing the calculations on this workbench it is apparent that this version will not work for 2 reasons. First the proper rate torsion coil spring that fits in these dimensions will only turn 3 revolutions. The gear/screw ratio requires that the transverse shaft turns 50 revolutions. Second the gear ratio with all the same size gears gives a final ratio of 150:1. So it would require too much hand crank velocity to reach 15mm/s. There will be a V-5.0 workbench to address these issues.