Chucks or sockets – With fluid-pressure actuator
Reexamination Certificate
1999-05-27
2001-02-13
Bishop, Steven C. (Department: 3722)
Chucks or sockets
With fluid-pressure actuator
C092S106000, C092S144000, C165S047000
Reexamination Certificate
active
06186515
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a chuck actuator. More particularly this invention concerns an air-cooled actuator for a lathe chuck.
BACKGROUND OF THE INVENTION
A standard chuck assembly has an actuator cylinder centered on and rotatable about an axis but substantially nondis-placeable relative to the axis and a chuck housing spaced axially from the cylinder. A tubular connecting shaft extending along the axis is connected fixedly between the cylinder and the chuck housing so that the cylinder, connecting shaft, and chuck housing rotate jointly about the axis but do not move along the axis. A chuck piston axially displaceable in the chuck housing has an inner end turned axially toward the actuator cylinder and an actuator piston is axially displaceable in the cylinder. The chuck piston and actuator piston are axially interconnected by a shaft assembly comprising an actuator shaft fixed to the actuator piston and having an outer end and a chuck shaft having an inner end connected to the actuator-shaft outer end and an outer end connected to the chuck-piston inner end. The chuck has radially displaceable jaws operated by its piston so that a workpiece can be gripped between these jaws and rotated about the axis for machining.
The actuator piston defines in the actuator housing a pair of compartments and the actuator housing has a rearwardly extending connection sleeve formed with a pair of passages each having one end opening into a respective one of the compartments and an opposite end opening radially outwardly at locations offset axially from each other and from the piston and actuator housing. A distributor body is mounted on this connection sleeve and has fittings connected to two fluid supply lines that can be alternately pressurized and depressurized. This body is rotatable about the main axis on the connection sleeve and can even move axially limitedly with this connection sleeve.
Fluid can be fed under pressure alternately to the fittings to pressurize and depressurize the respective compartments and thereby axially displace the piston in the cylinder since the cylinder is connected to the chuck body and the piston to the chuck-actuating piston or member for actuation of the actual chuck jaws. Double check valves built right into the piston inhibit flow out of either of the compartments unless one of the passages is pressurized.
The region where the connector body rides on the rapidly rotating connection sleeve of the actuator housing can get fairly hot, especially as seals are provided flanking the locations where radially inwardly or outwardly open grooves on one of the parts confront radially outwardly or inwardly open ports on the other part for fluid transfer between the parts. In order to cool this region it has been suggested simply to provided fan-like vanes on the cylinder housing, which rotates at high speed with the chuck body, to force air over this region.
The problem with this system is that the air-circulating structure generate considerable hum. The machine-shop environment is noisy enough under the best of circumstances, so this additional source of sound is considered highly undesirable.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved air-cooled chuck actuator.
Another object is the provision of such an improved air-cooled chuck actuator which overcomes the above-given disadvantages, that is which runs quietly.
SUMMARY OF THE INVENTION
The chuck actuator according to the invention has a cylinder housing rotatable about a main axis and forming a chamber, a piston axially subdividing the chamber into a pair of compartments and axially displaceable in the chamber, and a stem centered on the axis, extending from the housing, and formed with a pair of passages each having one end opening into a respective one of the compartments and an opposite end opening on the stem offset from the piston. A distributor body is rotatable about the axis on the stem and has in turn connections for feeding fluid under pressure into the opposite ends of the passages for axially displacing the piston in the chamber. In accordance with the invention the cylinder housing is formed with cooling openings directed at the distributor body.
The air forced through the cooling openings is less turbulent than with the fan vanes of the prior art, so the system is fairly quiet. At the same time there is sufficient air flow to provided the necessary cooling and thereby avoid overheating of the critical distributor joint.
Preferably in accordance with the invention the cylinder housing has an annular ridge formed with the cooling openings. Thus these openings can be oriented as wanted, need not inherently be set at an outside-to-inside angle.
The openings according to the invention are of axially decreasing cross section toward the distributor body, preferably frustoconical. This formation accelerates the air passing through them so that it will be projected further over the distributor.
According to a further feature of the invention each of the openings is centered on a respective opening axis inclined at an acute angle to a respective plane including the main axis. Thus air flow is not simply tangential past the openings, but is actually into them. This reduces turbulence and, once again, noise generated while increasing heat exchange and cooling capacity.
Since a chuck can be rotated in two directions, according to the invention the openings are arranged in pairs and one opening of each pair is inclined positively with respect to the respective plane and the other opening of each pair is inclined negatively with respect to the respective plane. Thus no matter which direction the actuator is rotating, half of the openings will be catching air. The openings are generally angularly equidistant about the axis.
To maximize internal heat exchange with the air flow going over the entire distributor body, the distributor body is formed with a helicoidal cooling rib. Such ribs increase the heat exchange by increasing the surface actually contacted by the cooling air flow. In addition in accordance with the invention each cooling rib extends at an angle corresponding to that of the openings. This ensures even smoother, less turbulent flow for quieter and more efficient operation. Furthermore the actuator is provided with an air-conducting sleeve surrounding the body.
REFERENCES:
patent: 3285328 (1966-11-01), Woodward
patent: 4319516 (1982-03-01), Rohm
patent: 4523632 (1985-06-01), Nobukawa et al.
patent: 30 16 088 (1980-11-01), None
patent: 2440801 (1980-06-01), None
patent: 2034624 (1980-06-01), None
patent: 2135606 (1984-09-01), None
patent: 58-102608 (1983-06-01), None
patent: 6-190615 (1994-07-01), None
Bishop Steven C.
Dubno Herbert
Rohm GmbH
Wilford Andrew
LandOfFree
Air-cooled hydraulic chuck actuator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Air-cooled hydraulic chuck actuator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Air-cooled hydraulic chuck actuator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2574671