Patent ID: 8469074

Claim:
A pressure control mechanism for use in a bonding machine that joins two superimposed and mated first and second parts together which parts have contacting portions that abut one another over a predetermined contact area, wherein the bonding machine includes a pair of fixtures with a first fixture contacting the first part and a second fixture contacting the second part during a bonding process, and wherein the bonding machine comprises a powered actuator for moving the first fixture towards the second fixture along an axis of movement to compress the parts against one another along the axis of movement to assist in joining the parts together during the bonding process along the contact area therebetween, which comprises: (a) a base; (b) a mounting plate movable relative to the base along the axis of movement, wherein the mounting plate carries the second fixture such that the mounting plate and the second fixture move together as a unit; (c) a plurality of springs interposed between the base and the mounting plate which springs are compressed during the bonding process, and wherein the springs have a pre-selected compression constant such that the springs when compressed by a pre-determined distance during the bonding process will apply a pre-determined, calculated force over the contact area of the parts to achieve a desired pressure between the parts that is sufficient to substantially close any gaps between the parts occurring over the contact area to help ensure a good bond between the parts over the contact area; (d) a plurality of powered pistons with each piston comprising a cylinder and a head that is extensible and retractable from the cylinder, and wherein the heads of the pistons engage against an exterior surface of the second part when the pistons are actuated to apply pressure to the parts in addition to the pressure imparted to the parts by the springs to further force the parts together along the contact area, wherein the cylinders of the piston are carried on and are movable with the unit comprising the mounting plate and the second fixture, and wherein the cylinders of the pistons terminate in input ends that are located in a cavity in the base underlying the mounting plate with the input ends of the cylinders being connected by hoses to a pressurized fluid source.