Design and Kinematic Analysis of a High-Speed Mechanical Hammering Machine Using a Cycloidal Cam Mechanism

This paper worked a cam-driven mechanical hammer through from motor to hammer by calculation. A 1 HP, 1440 rpm motor and a three-stage V-belt reduction of 14.06:1 give a camshaft speed of 102.4 rpm, one blow every 0.586 s. A cycloidal cam that assigns 99° to the downstroke, 15° to a dwell, 180° to the return and 66° to a second dwell produces a peak hammer velocity of 1.24 m/s and 1.53 J of kinetic energy for a 2 kg hammer, with a peak acceleration of 24.1 m/s2 and a peak lever load of 67.9 N. Compared with a symmetric cycloidal motion at the same stroke and speed, the energy is 3.3 times greater for a lever load 2.0 times greater and compared with simple harmonic motion it is 5.4 times greater. Reaching the same energy by adding mass would need a 6.6 kg hammer and a 113 N peak load. Materials and fabrication for the prototype cost INR 13,040. The results come with limits that should be stated plainly. Nothing has been measured, so the energy, velocity and loads are ideal values from a rigid-body calculation. The 1.53 J is the kinetic energy at mid-stroke and is delivered in full only if the work surface is placed there or the hammer can separate from the lever. The cam-driven peak velocity is below that of a free drop through the same stroke, so the advantage is over symmetric drives at the same speed. The pressure angle of about 34° exceeds the usual 30° limit; with the present 110 mm base circle, meeting it would need a descent angle of about 115° and would cost roughly a quarter of the energy. The spring preload, the shaft and bearing sizes and the contact stress in the cam have not been calculated here. Several steps would turn these calculations into tested results: instrumented measurement of hammer velocity and impact force on the prototype; a dynamic simulation of the cam, follower, lever and hammer that includes the compliance of the leaf spring; finite element checks of the frame, lever and shafts; a larger base circle or another adjustment to bring the pressure angle under 30°; and a comparison of other motion laws at the same 99° allocation. An adjustable stroke, speed control and guarding for the belts and cam would also be needed before any production use.

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