Gear cutting – milling – or planing – Milling – Cutter spindle or spindle support
Reexamination Certificate
1999-06-07
2001-02-27
Briggs, William (Department: 3722)
Gear cutting, milling, or planing
Milling
Cutter spindle or spindle support
C082S160000, C408S23900A
Reexamination Certificate
active
06193451
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to a holder adapted for the detachable mounting of cutting tools, said holder comprising a house and a clamping mechanism provided in said house. The clamping mechanism includes a male member adapted to engage in a female-like opening in the tool. The male member is movable to and fro between an inner end position, where the tool is clamped relative to the house, and an outer end position, where the tool is releasable from the house. The male member is moved by means of a piston device that is movable to and fro in a cavity within the house. The piston device separates outer and inner chambers to and fro which a hydraulic medium may be fed in order to move said male member towards one of said end positions.
BACKGROUND OF THE INVENTION
Tool holders of the kind defined above are frequently present in automatic machines for metal cutting, i.e. turning, milling, drilling and the like. A benefit with this type of holder is that it allows quick and simple tool exchanges. However, a problem in connection with previously known tool holders is the adjustment of the pressure of the hydraulic medium, usually oil, that is fed into one of the chambers of the house in order to either clamp the tool or push out the same. The adjustment of the pressure is especially tricky as regards the hydraulic medium that is fed into the outer chamber in connection with clamping of the tool. If the tool is clamped by an excessively large force, the components included in the clamping mechanism may be damaged or at least, in the long run, be worn out too quickly. Therefore, it is desirable to limited the maximum pressure of the hydraulic medium that is fed to the outer chamber.
A theoretically feasible solution of the problem mentioned above would be to provide an external pressure adjusting system in the hydraulic system of the automatic machine itself, i.e. to provide, in one way or another, a fine adjustment of the pressures to both of the hydraulic medium chambers of the tool holder. However, this is for several reasons not an attractive solution. Since the pressure adjustment in such a case would take place at a distance from the tool holder, unavoidable pressure variations in the hydraulic system as a whole (as a consequence of the fact that other functions in the machine is activated or inactivated) may lead to the consequence that the outer chamber will not safely operate with a certain maximum pressure. Further, a remote controlled pressure adjusting system would run a risk that individual operators could too easily change the working pressures in the respective chambers in an uncontrolled way that is not always desired.
OBJECTS AND FEATURES OF THE INVENTION
The present invention aims at obviating the problems mentioned above and providing an improved tool holder. Thus, a primary object of the invention is to provide a tool holder that independently of any pressure variations being present in the hydraulic system as a whole, always guarantees that the hydraulic pressure in the outer chamber is maximized to an upper limit value. A further object is to provide a tool holder in which the adjustment of the hydraulic pressure calls for certain measures, more precisely in order to eliminate the risk that individual operators may change the pressure in an uncontrolled manner. Still a further object of the invention is to provide a tool holder that realizes the desired pressure adjusting function via structurally simple and inexpensive means.
SUMMARY OF THE INVENTION
According to the invention a holder is adapted for detachably holding a cutting tool. The holder comprises a house and a clamping mechanism mounted in a cavity of the house. The clamping mechanism includes a clamp element adapted for clamping a tool, and an actuating mechanism for moving the clamp element to a tool-clamping position. The actuating mechanism includes a piston mounted for reciprocation in the cavity. The piston divides the cavity into first and second chambers. The first chamber communicates with a source of pressurized hydraulic fluid for displacing the piston in a direction causing the clamping element to clamp a tool against the house. The piston includes a passage formed therein and communicating the first chamber with the second chamber. A valve disposed in the passage is biased to a passage closing position for normally blocking communication between the first and second chambers. The valve is exposed to pressure in the first chamber and is movable to a passage-opening position to relieve pressure in the first chamber when the pressure in the first chamber exceeds a predetermined value.
REFERENCES:
patent: 3842712 (1974-10-01), Bondie et al.
patent: 4008646 (1977-02-01), Hague et al.
patent: 4398326 (1983-08-01), Joerger
patent: 4583894 (1986-04-01), Mitchell
patent: 4746252 (1988-05-01), Jesinger
patent: 4930553 (1990-06-01), Grillo
patent: 5096347 (1992-03-01), Kumagai et al.
patent: 5193954 (1993-03-01), Hunt
patent: 5626325 (1997-05-01), Buchanan et al.
patent: 5662442 (1997-09-01), Taki et al.
patent: 5707186 (1998-01-01), Gobell et al.
Briggs William
Burns Doane Swecker & Mathis L.L.P.
Sandvik Aktiebolag
LandOfFree
Holder for the detachable mounting of cutting tools with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Holder for the detachable mounting of cutting tools with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Holder for the detachable mounting of cutting tools with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2610454