Ex-cell-o Gmbh

Bryant Grinder Corporation

Victor F Dzewaltowski

Lawrence I Millay

Walter Clinton Dodd

John M Check

Richard H Gile

Robert N Hobbs

Richard E Crossman

James Halvorsen

Kazimierz J Reda

Steven P Farmer

A workpart chuck centering mechanism moves towards the axis of rotation of the chuck as the chuck rotates in an eccentric non-centered position. The centering mechanism includes two independent shoes. Each shoe is driven by a servo-motor and encoder. The two shoes function in a cooperative manner to center the workpart. A sensing device monitors any eccentric movement of the workpart and controls the positioning of the shoes. The two shoes and the sensing device are mounted on a base which can pivot about the chuck axis. The directions of movement of the respective shoes are displaced 90.degree. relative to one another and intersect at the chuck axis.

Workpart chuck positioning mechanism with independent shoes

The workhead includes a spindle disposed on a base member and rotatable about a rotational axis. The spindle includes a chuck for fixedly clamping one end of an elongated workpart, such as a valve lifter body, having a bore between opposite ends with the longitudinal axis of the bore substantially coaxial with the rotational axis. A fluid bearing such as a hydrostatic bearing is disposed on the base member adjacent the other end of the workpart for providing pressurized fluid at sufficient locations around the other end to resist machining forces tending to deflect the other end off axis relative to the fixedly clamped end during machining of the bore to improve bore roundness and straightness.

Workhead with workpart chuck and workpart fluid bearing

A workpart chuck is provided with a centering member that is movable toward the axis of rotation of the chuck as the chuck rotates the workpart in an eccentric non-centered position. As the centering member moves the workpart, a sensing device senses the extent of changing eccentric movement of the workpart and generates an electrical signal that is indicative of the extent of such eccentric movement. The workpart is moved toward the chuck axis until the signal reaches a predetermined value indicative that the workpart is rotating about its axis; i.e., the workpart axis and chuck axis are substantially coaxial. The centering member is offset slightly relative to the chuck axis of rotation to assure that excessive movement of the centering member placing the workpart center beyond the chuck axis of rotation will not result in the workpart being driven to an extremely eccentric position and possibly even off the face of the chuck. The sensing device will detect a sudden shift of the workpart position relative to the centering member indicative of such movement beyond center, whereupon the control system will cause the centering member to retract a small distance and advance in a new attempt to center the workpart.

Workpart centering mechanism for a chuck

A combined grinding and EDM apparatus has an indexable rotary turret with four work heads secured thereon to locate a pair of nozzle body blanks with their longitudinal axes in spaced parallelism; and either three or four compound cross and longitudinal slide assemblies carrying grinding tools, lapping tools or non-contact machining tools which work on the blanks to machine the face and to form a valve guide bore and a valve seat shaped as a frustrum of a cone whose axis is concentric with the bore, the valve seat cone surface having a small end diameter to large end diameter ratio in the order of 1-50.

Combined bore seat face grinding, EDM and lapping method for finishing

A combined grinding and EDM apparatus has an indexable rotary turret with work heads secured thereon to locate a pair of nozzle body blanks with their longitudinal axes in spaced parallelism; and compound cross and longitudinal slide assemblies carrying either grinding tools or non-contact machining tools which work on the blanks to form a valve guide bore and a valve seat shaped as a frustrum of a cone whose axis is concentric with the bore; the valve seat cone surface having a small end diameter to large end diameter ratio in the order of 1-50.

Method of combining grinding and EDM operation for finishing fuel

A workpart fixture for an unbalanced drill bit lug includes a support having a vee-shaped recess with an included angle substantially the same as vee-shaped intersecting surfaces on the drill bit lug to receive same and a fluid actuated clamp assembly carried on an arcuate slide which is movable in a circular arc path laterally relative to the drill bit lug generally about a centerline through the drill bit lug body to accommodate right or left linear or angular offset of the line of intersection of the vee-shaped lug surfaces and to optimize clamping force on the lug in the fixture. The clamp assembly includes a clamp lever which is pivotal toward and away from the drill bit lug by a fluid actuator and which carries swiveling clamp pads that seat against the drill bit lug when the clamp lever is actuated by the cylinder.

Drill bit lug fixture

In the internal grinding of a cylindrical bore having an oil or similar groove which adversely affects the bore roundness achievable, one or more streams of liquid coolant are directed over the grinding wheel during rough grinding at a high wheel feed rate and only a mist of liquid coolant droplets suspended in a compressed air stream is directed over the wheel once the high wheel feed rate has been reduced to the lower wheel feed rate associated with finish grinding. Means are provided for terminating the liquid coolant streams at the time the wheel feed rate is changed or after a short delay period thereafter to establish equilibrium finish grind conditions. Preferably, the change from one or more liquid coolant streams to the coolant mist is made in response to a detected decrease in wheel spindle motor power.

Close tolerance internal grinding using coolant mist

An improved method to surface condition a super-abrasive grinding wheel by intermittently moving the wheel to a stationary wheel conditioner unit mounted adjacent the grinding wheel with the conditioner unit having a consumable element engaged by the grinding wheel to condition the grinding wheel including a dual compensation method having the steps of grinding a predetermined number of workpieces to establish a first predetermined depth of super-abrasive wheel wear; periodically conditoning the wheel surface by consuming a second predetermined depth from a consumable reconditioning tool surface; and producing a first compensation of a grinding wheel by controlling the position of the super-abrasive wheel with respect to the workpiece to maintain an apparent wheel wear depth within the range of desired workpiece tolerance and producing a second compensation of a grinding wheel conditioner by contacting the wear surface of the super-abrasive wheel with the reconditioning tool surface and advancing it into and away from the tool surface a distance equal to the second predetermined depth each time that the wheel is reconditioned so as to assure that individual grains of the super-abrasive constituent of the wheel will extend beyond the bonding material constituent of the wheel to maintain cutting efficiency of the wheel following the reconditioning step.

Automatic dual compensation grinding wheel conditioner

A centerless grinding machine is provided with a ferris wheel arrangement having multiple, circumferential pockets in which an annular workpiece is received from a loading chute, is internally ground by a grinding wheel and is discharged into an unloading chute after grinding by indexed rotation of the ferris wheel. The grinding machine includes a stationary alignment shoe cooperating with an individual alignment shoe carried in each pocket of the ferris wheel. In the grinding position, the stationary shoe preferably is at the 3 o'clock position while the alignment shoe in the adjacent pocket is at the 6 o'clock position. The grinding wheel is positioned on one side of the ferris wheel and a workpiece driver means is positioned on the opposite side. With the inventive grinding machine, annular workpieces, such as bearing raceways, can be loaded, ground and unloaded in rapid succession with high accuracy maintained during grinding.

Centerless grinding machine with ferris wheel arrangement

A grinding machine is provided with a workhead support means having pivotable shaft means on which the support means is pivoted by a servomotor/pinion arrangement controlled by a programmable controller and a position indicating means on the pivotable shaft means that inputs angular shaft position signals to the controller. Adaptive control components may also be included in the control arrangement. The workhead support means is thereby pivotable to vary the angular relationship of the workpart axis to the grinding wheel axis to effect a desired taper or contour grind or to compensate for changes in grinding parameters causing out of tolerance ground workparts. Special releasable clamps are provided to fix a desired position of the workhead support means and yet release same for pivoting movement. Fluid lift mechanisms are also provided to reduce friction between the workhead support means and the adjacent machine base member during pivoting.

Grinding machine with CNC pivotable workhead

An electromagnet is disposed between a pair of bearings rotatably mounting a spindle in the housing of a machine workhead, such as the workhead of a grinding machine. The magnetic flux from the electromagnet is guided by the spindle extending therethrough to its workpart driving end located outside the housing. Bearing shoes engaging the workpart are connected to the housing so as to complete the magnetic flux path to the electromagnet through the housing. Non-magnetic shields are disposed between the bearings and the electromagnet and housing to prevent wear debris accumulation and etching of the bearing components from magnetic flux effects.

Machine workhead with magnetic driver

An interchangeable and stationary grinding wheel dressing structure mounted on a cantilevered base unit having the grinding wheel carried to it for dressing.

Stationary grinding wheel dressing unit

An electro-mechanical control system for controlling all of the movements of one or more slides on a single workhead grinding machine. A programmable controller is interfaced with a digital to analog converter or feed control which in turn controls a drive motor that is directly connected to a screw actuator means that directly controls the movements and positions of a slide. The positioning accuracy of the control system is derived from the accuracy of the electronic control components and the stability of the machine. The control system can control the operative movements of each slide in a compound slide assembly, simultaneously or independently, for a part of a grinding machine cycle. The compound slide assembly may alternatively carry a rotating grinding wheel or a workhead that is reciprocated at high speed for a grinding operation on a workpiece.

Growing community of inventors

Springfield, VT, United States of America

Victor F Dzewaltowski