Automatic counterbalance control circuit

#The present invention is directed to a control circuit for automatically counterbalancing the moving components of a press.

#It is well known that in a machine such as a press, it is necessary to keep the moving components in equilibrium by using air pressure to counterbalance the moving members on the eccentric such as a reciprocable ram having a die half mounted thereon. More specifically, in the operation of such a press, on the downstroke if there is excess counterbalancing then the press does more work than necessary causing excess wear on the moving parts, e.g., the flywheel, cam, etc. Similarly, on the upstroke of the ram, if there is insufficient counterbalancing, then the working members tend to fall away from the eccentric as the flywheel energy is restored.

#Since each die used on a press has its specific configuration and weight, a change is required in the counterbalance to maintain equilibrium each time a different die is placed on the press.

#The various objects and advantages of the present invention will become more apparent upon reading the following detailed description taken in conjunction with the drawings.

#In the drawings, wherein like reference numerals identify corresponding components:

#FIG. 1 is a partial perspective, partial schematic representation of a press which is to be counterbalanced by the circuit of the present invention;

#The present invention has a particular utility in automatically counterbalancing the moving components of a press 10 having a reciprocable ram 11 and a stationary bed 12. Upper and lower die halves are placed upon the ram and bed, respectively, as is conventional, and the speed of the ram is controlled by an electric motor 13.

#Positioned on the ram 11 is a pneumatic cylinder 15 to which a supply of air 16 may be introduced such as through a regulator 17. The regulator 17 is controlled by a small bidirectional electric motor 18; driving the motor in the first direction increases air in the cylinder and driving the motor in the opposite direction permits air to be bled from the cylinder.

#FIG. 2 illustrates, schematically, the operation of a press cycle relative to a cam or eccentric, starting at 0.degree.. The interval from zero degrees to 180.degree., proceeding clockwise, corresponds to the downstroke of the press and interval between 180.degree. and 360.degree., proceeding clockwise, corresponds to the upstroke of the press.