Turntable support structure for radius mills and the like

In a contour grinding machine of the type having an elongated bed, a tool-carrying carriage movable longitudinally of said bed, a horizontally-disposed bedplate resting in fixed position upon said bed in the path of the tool-carrying carriage, a turntable mounted atop the bedplate for relative movement along the surface thereof about a vertical axis, and a second carriage for carrying a workpiece mounted stop the turntable for movement therewith about said vertical axis as well as independent movement relative thereto and to the tool-carrying carriage, the improved turntable support subassembly which comprises:

• a pair of pads depending from the underside of the turntable in spaced relation to one another and to said vertical axis of turntable movement positioned and adapted to slide along the upturned surface of the bedplate;
• a pivot pin located at the vertical axis of turntable movement cooperating with the pads to define a three-point turntable support, said pivot pin including a stem portion journalled for rotation in the bedplate about said axis of turntable movement and a ball atop said stem portion having a spherical surface whose center lies on said axis;
• a bearing-receiving cavity in the underside of the turntable positioned and sized to loosely receive the pivot pin ball;
• an upper socket bearing segment having the underside thereof shaped to receive the top of the pivot pin ball for limited universal movement;
• first adjustment means mounting the upper socket bearing segment within said bearing-receiving cavity for vertical adjustment along said axis of turntable movement, said upper socket bearing segment and first adjustment means cooperating with one another upon actuation of the latter to raise and lower the portion of the turntable resting on the pivot pin relative to those portions supported on the pads;
• a lower socket bearing segment apertured and shaped to loosely receive the stem portion of the pivot pin and journal the underside of the pivot pin ball for limited universal movement when placed thereagainst;
• and, second adjustment means mounted the lower socket bearing segment within said bearing-receiving cavity for independent vertical adjustment along said axis of turntable movement, said second adjustment means being operative upon actuation in a manner to raise the lower bearing segment into contact with the underside of the pivot pin ball to complete the socket therefor and retain said turntable for limited tiltable movement effective to accommodate unevenness in the bedplate surface over which the pads slide.