Concrete block molding machine having continuously driven vibrating shaft mechanism which can be programmably vibrated and method of programmably vibrating such machines

摘要

A cement block molding machine has a vibratible mold box incorporating at least one molding cavity for a cement mixture which is to be densified in the cavity. A continuously driven shaft (15) assembly mounts an eccentric fixed portion and a circumferentially adjustable balancing mass. The shaft assembly (5) has a cylinder (c) with a piston (26) therein, connected to the mass (25a) to produce rotary motion of the mass (25a) relative to the fixed eccentric portion (18, 19). A spring (28) of predetermined rate opposes this. The pressure of the fluid introduced is varied to change the amplitude of the vibration imparted during each cycle.