Fluid handling – Systems – With running joint between movable parts of system
Reexamination Certificate
2002-10-21
2003-12-30
Chambers, A. Michael (Department: 3753)
Fluid handling
Systems
With running joint between movable parts of system
C137S340000
Reexamination Certificate
active
06668859
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a hydraulic collet assembly, more particularly to a hydraulic collet assembly with a valve unit for relief of pressure in a fluid injection passage in the hydraulic collet assembly.
2. Description of the Related Art
Referring to
FIG. 1
, a conventional hydraulic collet assembly is shown to include a machine body
31
, a stationary wall body
32
disposed in the machine body
31
and formed with a fluid injection passage
321
, a rotary shaft
33
disposed coaxially through the stationary wall body
32
and cooperating with the stationary wall body
32
to define a clearance
300
therebetween, a bearing unit
331
disposed between the stationary wall body
32
and the rotary shaft
33
to facilitate rotation of the rotary shaft
33
relative to the stationary wall body
32
, a tubular slidable seat
35
disposed in and cooperating with the rotary shaft
33
to define a piston-receiving chamber therebetween, a piston
34
disposed movably within the piston-receiving chamber and cooperating with the rotary shaft
33
to define a gap
34
G therebetween, and a collet
36
disposed in the tubular slidable seat
35
and coupled to the piston
34
for synchronous movement therewith.
The rotary shaft
33
is formed with a fluid channel
332
in fluid communication with the fluid injection passage
321
in the stationary wall body
32
and extending to and in spatial communication with the piston-receiving chamber. The collet
36
has clamping jaws confining an open mouth. When high-pressure hydraulic oil is injected into the gap
34
G through the fluid injection passage
321
and the fluid channel
332
, the collet
36
moves together with the piston
34
toward the fluid channel
332
in such a manner that the open mouth in the collet
36
is reduced in cross-section so as to clamp a rod-shaped workpiece (not shown) therein.
Some disadvantages that result from the use of the aforesaid conventional hydraulic collet assembly are as follows:
During the clamping operation of the workpiece in the collet
36
, the high pressure oil is introduced into the bearing unit
331
through the clearance
300
formed between the rotary shaft
33
and the stationary wall body
32
. Since the fluid injection passage
321
and the fluid channel
332
have to be kept under a high pressure state so as to maintain the collet
36
in the clamping state, the pressure of the hydraulic oil accumulated in the clearance
300
is relatively high. As such, friction force between the stationary wall body
32
and the rotary shaft
33
is relatively large during rotation of the rotary shaft
33
, which may result in an undesirable increase in the temperature of the bearing unit
331
and the collet
35
, and a reduction in the viscosity of the hydraulic oil in the bearing unit
331
, thereby shortening the service life of the components of the conventional hydraulic collet assembly.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide a hydraulic collet assembly with a valve unit for relief of pressure in a fluid injection passage so as to prolong the service life of the components of the assembly.
Accordingly, a hydraulic collet assembly of the present invention includes: a machine body; an annular stationary wall body disposed in the machine body and formed with a fluid injection passage therein; a hollow rotary shaft co-axially extending through the stationary wall body, defining a piston-receiving chamber, and formed with a fluid channel extending to and in spatial communication with the piston-receiving chamber; and an annular piston movably received in the piston-receiving chamber in the rotary shaft in such a manner that the piston moves away from the fluid injection passage upon injection of a high pressure hydraulic oil into the piston-receiving chamber through the fluid injection passage and the fluid channel. The piston defines a collet-receiving chamber therein. A collet is movably received in the collet-receiving chamber, and is coupled to the piston for synchronous movement therewith. The collet has clamping jaws confining an open mouth that is reduced in cross-section when the piston moves away from the fluid channel. A bearing unit is disposed between the stationary wall body and the rotary shaft. A valve unit is disposed between the stationary wall body and the rotary shaft, and includes a tubular valve sleeve sleeved on the rotary shaft. The valve sleeve includes an annular wall body formed with a valve opening therein, a valve chamber extending from the valve opening, a valve inlet in fluid communication with the fluid injection passage and the valve opening, and a valve outlet in fluid communication with the valve chamber and the fluid channel. The valve unit further includes a check valve movably mounted in the valve chamber and operable to move between an open position, in which the valve opening is opened, thereby permitting fluid communication between the fluid injection passage and the fluid channel through the valve inlet and outlet, and a closed position, in which, the valve opening is closed by the check valve, thereby preventing fluid communication between the fluid injection passage and the fluid channel.
REFERENCES:
patent: 2310309 (1943-02-01), Orr
patent: 3020057 (1962-02-01), Gamet
patent: 3922952 (1975-12-01), Roddy et al.
patent: 3923133 (1975-12-01), Chivari
patent: 4040338 (1977-08-01), Wilson et al.
patent: 4168654 (1979-09-01), Wilson et al.
Chambers A. Michael
Marger Johnson & McCollom PC
LandOfFree
Hydraulic collet assembly with a valve unit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hydraulic collet assembly with a valve unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydraulic collet assembly with a valve unit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3165928