Track link pin bore - hydraulically prestretched
AssigneeCaterpillar Tractor Co.
InventorDuane L. Burk
Life of this patent
Estimating the term…
Abstract
A method and apparatus for enlarging a bore in a work piece including means for sealing the bore, a source of hydraulic fluid and a hydraulic pressure amplifier for introducing the fluid into the cylindrical bore and amplifying the pressure of the fluid to a value exceeding the yield strength of the work piece, thereby forcing the walls of the bore to yield until the bore reaches a predetermined diameter. The hydraulic amplifier means includes a plurality of series connected cylinders of increasing diameter so that the fluid acting on each cylinder is multiplied by the pressure of the preceding cylinder.
Claims3
A method of preparing a pin in tight press-fitting relation within a bore in a workpiece, comprising:
- sizing and locally strengthening a bore in a workpiece by the steps comprising:
- establishing a predetermined size for the bore;
- forming an undersized version of said bore in a workpiece;
- increasing the size of said bore by the steps of applying a hydrostatic pressure to the walls of said bore, raising said pressure to exceed the yield strength of said workpiece locally of the walls of said bore and continuing said pressure until the walls of said bore have yielded and deformed to said predetermined size and been locally strengthened;
- and
- press-fitting a pin within said bore.
A method of preparing a pin in tight fitting relation within a bore in a workpiece, comprising:
- enlarging a bore by the steps comprising:
- forming a bore of a first predetermined diameter in a workpiece;
- and
- enlarging said bore to a second predetermined diameter by the further steps of sealing said bore, introducing a pressurized fluid into said bore, increasing the pressure of said fluid to a pressure exceeding the yield strength of said workpiece until the walls of said bore expand locally while the remainder of the workpiece absorbs all the force of said fluid without external assist to said second predetermined diameter;
- and
- press-fitting a pin within said bore.
Dependencies are inferred from the claim text.