Method and device for the dynamic lubrication of a power chuck

• US 20020033582A1
• Filed: 09/12/2001
• Published: 03/21/2002
• Est. Priority Date: 09/21/2000
• Status: Active Grant

• Current Assignee: Forkardt Schweiz GmbH (InCompass LLC)
• Original Assignee: Forkardt Schweiz AG
• Inventors: Bohler, Erwin
• Granted Patent: US 6,601,856 B2
• Time in Patent Office: Days
• US Class Current: 279/4.01
• CPC Class Codes: B23B 2250/12 Cooling and lubrication
• CPC Class Codes: B23B 31/16216 using fluid-pressure means to actuate the gripping means
• CPC Class Codes: B23Q 1/38 using fluid bearings or fluid cushion supports
• CPC Class Codes: B23Q 11/121 with lubricating effect for reducing friction F16C33/66 and F16H57/04 take precedence
• CPC Class Codes: B23Q 11/122 Lubricant supply devices F16N7/00 takes precedence
• CPC Class Codes: Y10T 279/12 with fluid-pressure actuator
• CPC Class Codes: Y10T 279/1291 Fluid pressure moves jaws via mechanical connection
• CPC Class Codes: Y10T 279/19 Radially reciprocating jaws

Abstract

Moving parts of the chuck are enclosed in a sealed cavity which is provided with a circulating lubrication. The power which drives its flow is derived from the force needed for opening and shutting the tongs of the chuck. In a chuck with hydraulically actuated jaws, this power is delivered by the pressure differences that occur between different parts of the hydraulic circuit actuating the jaws of the chuck and the hydraulic liquid acts also as lubricant.

Claims

1. Method for lubricating moving parts of a power chuck (mounted on the headstock of a machine tool) characterized in that said parts are enclosed in an essentially sealed cavity or form a boundary of the same, and in that some lubricating fluid enters the cavity and/or leaves it during the opening and closing movements of the chuck.

2. Method according to claim 1, characterized in that the pressure of the fluid in the cavity at least sometime exceeds the atmospheric pressure.

3. Method according to claim 2, characterized in that the bed track of at least one jaw of the chuck is fed with lubricating fluid flowing from the cavity.

4. Method according to any preceding claims for a chuck with hydraulically actuated jaws, characterized in that the intake and the output of fluid is actuated by the differences in pressure occurring in the hydraulic system of the chuck in order to open and close it.

5. Method according to claim 4, characterized in that the actuating fluid of the hydraulic system is used as lubricating fluid.

6. Power chuck with movable elements for opening and closing its jaws, characterized in that at least one such element is enclosed in or forms a boundary of an essentially sealed cavity which is at least temporarily connected through at least one intake conduit with a source of lubricating fluid.

7. Power chuck according to claim 6, characterized in that the slit of the bed track of at least one jaw of the chuck communicates with the cavity.

8. Power chuck according to claim 6 or 7, characterized in that the cavity is at least sometimes connected through an output conduit with a sink for the lubricating fluid.

9. Power chuck according to claim 8, characterized in that its jaws are operated hydraulically and that the intake and output conduits are connected with the hydraulic operating circuit of the jaws.

10. Power chuck according to claim 9, characterized in that at least some of said parts are mechanical elements for mechanically transmitting hydraulic actuating forces to the jaws.

11. Power chuck according to claim 9 or 10, characterized in that the hydraulic operating circuit comprises at least an actuating conduit provided with a first return valve for transmitting the pressure necessary for closing the chuck, and a relief conduit connecting the cavity with the actuating conduit, which relief conduit contains a second return valve and leads into the actuating conduit upstream of the first relief valve.

12. Power chuck according to claim 9 or 10, characterized in that the hydraulic operating circuit comprises at least a release conduit for transmitting the pressure necessary for opening the chuck, and a bypass conduit connecting the cavity with the release conduit.

13. Power chuck according to any of claims 8 through 12, characterized in that its intake and/or its bypass conduits contain a choking nozzle.

14. Power chuck according to any of claims 6 to 13, characterized in that the source of lubricating the fluid is stationary.