Force-balanced die casting apparatus

Claim 2

Apparatus for cyclically reciprocating at least one die section of a multi-section die comprising a prime mover, shaft means, first mechanical means connecting said shaft to said prime mover for rotation of said shaft, second mechanical means connecting said shaft to said reciprocatable die section, energy transfer means disposed in energy transfer relationship with said shaft for causing the torque forces imposed on said shaft to exchange torque forces between itself and said shaft so as to maintain the platen reciprocation apparatus in a force-balanced stated during the major part of the reciprocation cycle.

Claim 3

The apparatus of claim 1 wherein said energy transfer means comprises a cam secured to said shaft and rotatable therewith and a cam-follower biased in contact with said cam whereby rotation of said cam results in cyclic change in the degree of bias force exerted against said cam by said cam-follower and resultant cyclic change in the torque experienced by said shaft.

Claim 4

The apparatus of claim 2 wherein said cam follower is spring-biased in contact with said cam.

Claim 5

In a die casting machine, apparatus for cyclically reciprocating at least one die section of a multisection die between open and closed positions including a stressing of said die while in its closed position comprising a prime mover having an output significantly less than the required output for sTress-closing said die, means reciprocatably mounting said die section, means for intermittently connecting said die section mount means in driven connection with said prime mover and comprising shaft means, a Geneva Cross mechanism connected in driven relation with said prime mover, force multiplication means connecting said Geneva Cross mechanism to said shaft means whereby said shaft means is connected to said prime mover for rotation of said shaft means at preselected time intervals during a casting cycle and for preselected time durations, and, means connecting said shaft means to said die section mount means whereby rotation of said shaft means imparts reciprocatory motion to said die section mount means to move said die section between its open and closed positions, and, means operative with the rotational movement of said shaft means to absorb and dispense torque respectively from and to said shaft means in accordance with a preselected program whereby the cumulative force ahead of said shaft means is substantially balanced with the cumulative force behind said shaft means during the major part of a casting cycle and including means to impart a relatively great stress-closing force to said die section and subsequently absorb such stress-closing force independently of said prime mover.

Claim 6

In a die casting machine, apparatus for cyclically reciprocating at least one die section of a multisection die between open and closed positions including a stressing of said die while in its closed position comprising a prime mover having an output significantly less than the required output for sTress-closing said die, means reciprocatably mounting said die section, means for intermittently connecting said die section mount means in driven connection with said prime mover and comprising shaft means, a Geneva Cross mechanism connected in driven relation with said prime mover, force multiplication means connecting said Geneva Cross mechanism to said shaft means whereby said shaft means is connected to said prime mover for rotation of said shaft means at preselected time intervals during a casting cycle and for preselected time durations, and, means connecting said shaft means to said die section mount means whereby rotation of said shaft means imparts reciprocatory motion to said die section mount means to move said die section between its open and closed positions, and, means operative with the rotational movement of said shaft means to absorb and dispense torque respectively from and to said shaft means in accordance with a preselected program whereby the cumulative force ahead of said shaft means is substantially balanced with the cumulative force behind said shaft means during the major part of a casting cycle and including means to impart a relatively great stress-closing force to said die section and subsequently absorb such stress-closing force independently of said prime mover.

Claim 7

The invention of claim 4 wherein said means operative with said shaft means to absorb and dispense torque comprises a cam having a selected contoured peripheral surface secured to said shaft means, a cam-follower, means biasing said cam-follower in contact with the peripheral surface of said cam such that rotation of said shaft means results in rotation of said cam and cyclic compression and relaxation of said baising means and resultant cyclic transfer of torque respectively from and to said shaft means.

Claim 8

The invention of claim 4 wherein said cam is provided with a generally elliptical peripheral surface and including a notch portion at one apex of said elliptical surface whereby movement of said cam-follower into said notch imparts a relatively great torque to said shaft means to stress-close said die and movement of said cam-follower out of said notch results in absorption of said stress-closing force.

Claim 9

The invention of claim 4 wherein said means connecting said shaft means to said die section mount means comprises crank means secured to said shaft means and rotatable therewith, and link means pivotally connecting said crank means to said die section mount means.