Grinding machine spindle

Details Grinding machine spindle Grinding machine spindle

1999-12-30

2001-08-21

Eley, Timothy V. (Department: 3723)

Abrading

Abrading process

Combined abrading

C451S273000

Reexamination Certificate

active

06277002

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to machine tools and particularly to a machine tool in which material is removed from a workpiece by engagement with a rotating tool, more particularly a grinding wheel.
BACKGROUND TO THE INVENTION
In many grinding processes, eg. in the manufacture of cams and crankshafts, it is usual for the initial major grinding operation to be performed by rough grinding using a coarse grade grinding wheel and for the final grinding operation to be performed by a fine grade grinding wheel. If the whole grinding process is to be performed on a single machine then two main options are available: either the machine has a single spindle which means that at each successive grinding operation the coarse wheel must be replaced by the fine wheel and vice versa, which significantly increases the total time required to grind a component; or alternatively the machine must be designed to have two spindles carrying respectively coarse and fine grinding wheels, which considerably increases the complexity and hence cost of the grinding machine.
It is an object of the present invention to produce an improved method of and apparatus for grinding, in which the coarse rough and final grinding operations are performed on a single spindle of a machine tool.
SUMMARY OF THE INVENTION
According to the present invention there is provided a machine tool having a single rotatable spindle on which is mounted a first cutting tool at a fixed position relative to the spindle and a second cutting tool adjacent the first tool, and slide means for slidably moving the second tool relative to the first tool to either retract the second tool or to extend it into an operational position.
Advantageously the first and second tools are disposed at one end of the spindle, the slide means moving the second tool in a direction axial of the rotational axis of the spindle, so that the tools successively engage axially with a workpiece.
In this arrangement the second tool is preferably mounted radially outside the first tool.
The first and second tools may be first and second grinding wheels, in particular cup-shaped grinding wheels. Since small errors may occur in the positioning of the second grinding wheel, the latter is preferably the coarse wheel for rough grinding while the first wheel is the finishing wheel.
The slide means may comprise an annular member and activating means for moving the annular member between forward and retracted positions.
The annular member is preferably radially inwardly directed for slidably engaging with a first cylindrical outer surface of the spindle.
Preferably the annular member is arranged in the form of an annular piston, the spindle forming an annular chamber at each side of the piston.
Where the radial element is an annular piston, the activating means may comprise means for feeding fluid under pressure to either one side or the other of the piston. The fluid may be hydraulic oil or more preferably air under pressure which is fed through passages in the spindle to ports extending respectively into the two annular chambers.
The annular piston may incorporate a sealing ring eg. of resiliently deformable material, which is sealingly engagable with the first outer surface of the spindle.
The annular piston may be generally T-shaped in section, there being an outer annular limb on each side of the piston, the limb which is adjacent the first tool carrying the second tool.
The limbs may slidably engage with respective second cylindrical outer surfaces of the spindle.
The second outer surfaces may similarly incorporate sealing rings eg. of resiliently deformable material to sealingly engage with the respective limbs of the piston.
The piston preferably carries a location device at each side for engaging with respective location devices in the spindle, so that the piston is prevented from rotating relative to the spindle at each extremity of its sliding movement.
The location means may take the form inter-engaging teeth, which provide both radial and axial location.
Means may also be provided to prevent rotation of the piston relative to the spindle during sliding movement. This may take the form of a pin formed on the spindle or piston which is engagable with a corresponding hole in the piston or spindle respectively.
The invention also extends to a method of machining a workpiece using a single spindle machine tool, comprising mounting a first cutting tool fixedly to the end of a spindle and mounting on the spindle a second cutting tool for axial sliding movement relative to the first tool, and further comprising the steps of extending the second tool into its operating position, rough machining the workpiece with the second tool, retracting the second tool, and finish machining the workpiece with the first tool.
In the preferred method the first and second tools are cup-shaped grinding wheels, the second wheel being the rough grinding wheel.


REFERENCES:
patent: 3778179 (1973-12-01), Rivas
patent: 3885925 (1975-05-01), Tatar
patent: 57-168856 (1982-10-01), None

Affiliated with

Also associated with

Rating

Grinding machine spindle does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Grinding machine spindle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Grinding machine spindle will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2537291