Turning – Process of turning
Reexamination Certificate
2000-04-04
2001-11-20
Tsai, Henry (Department: 3722)
Turning
Process of turning
C082S001300, C082S113000, C082S118000, C029S417000
Reexamination Certificate
active
06318221
ABSTRACT:
FIELD OF THE INVENTION
This invention relates broadly to automatic machining equipment and, more particularly, pertains to an integrated machine tool for performing a series of processing steps in the manufacture of sealing rings.
BACKGROUND OF THE INVENTION
Sealing rings are not circular in the free, uninstalled state. They have a sinusoidal shape that must be obtained with non-standard means. The shape has been previously obtained with mechanical cams, heat shaping, and other more expensive and laborious methods.
Previously, sealing rings have been manufactured from individual castings that were cast slightly larger than the finished ring. Various methods were then used to bring the ring to its final shape. All of these methods use size-specific tooling and materials that are fairly expensive. The casting method also involves fairly lengthy setups on machinery, and also requires multiple machining operations for the outside diameter and the inside diameter. This process has been used for both large and small quantities of rings.
Another method widely used is the cold “tube process”. This process involves a tube of material that is usually between three inches and twenty-four inches long. The tube is cast to outer diameter and inner diameter dimensions that have an amount of material that can be machined away to leave nearly finished dimensions for the completed rings. The tube is then parted or cut into individual rings. The individual rings must still have further machining done to them to achieve the final shape. This process is actually more expensive than the individual casting method previously described, but has the advantage of using readily available tubing, as opposed to having to tool a foundry for individual castings. Another disadvantage is that it is difficult to fixture or “chuck” a tube without deforming it, thus effecting the final shape. It is more suited for small quantities of rings.
A further process that has been documented is a modified version of the “tube process”, as set forth in U.S. Pat. No. 5,085,109 issued Feb. 4, 1992. In this operation, the sealing rings are machined from tubing, but the machining is done in a non-circular method and machines the final ring shape immediately from the tube without requiring a secondary machining operation for the final outer diameter and inner diameter shape. The final contour is regulated by a computer control that has the correct cross-sectional shape of the ring programmed into it. This process has been further improved in U.S. Pat. No. 5,313,694 issued May 24, 1994.
Despite the attempts of the prior art, there remains a need to manufacture sealing rings in a manner which will utilize less expensive material, significantly reduced tooling and set-up costs, eliminate casting and tubing procedures, and possess the versatility to produce rings of various sizes.
SUMMARY OF THE INVENTION
The present invention advantageously provides an automated sealing ring forming process which operates upon solid bars of stock material to sequentially position the material to rough cut, finish turn, trepan and cuts off rings in an extremely efficient manner which makes optimal use of the stock material.
It is one object of the present invention to provide an improved, cost effective apparatus and method for forming sealing rings other than by a casting or tubing process.
It is another object of the present invention to provide a method of repetitively machining a solid core of material so as to produce progressively smaller diameter sealing rings.
It is an additional object of the present invention to provide a computerized numerical machine control (CNC) machine tool having reduced tooling costs and setup time required.
It is also an object of the present invention to provide a method for processing sealing rings which avoids the use of multiple jigs and measuring devices.
A further object of the present invention is to provide an automated machine tool having a multi-tool slider mechanism movable in synchronism with a rotating spindle carrying stock material to be transformed into a sealing ring.
In one aspet of the invention, a machine tool is provide for performing machining of a cylindrical workpiece having an outer periphery and a face connected for rotation at the end of a driven spindle structure having a slider arrangement for providing multiple tool engagement with the workpiece. A control system is also provided for coordinating movement of the spindle structure and the slider arrangement whereby the slider arrangement oscillates radially relative to the spindle. An improvement resides in a slider structure having a first oscillating tool for turning the outside diameter of the workpiece to a sinusoidal shape, and a second tool for plunging into the face of the workpiece to form a sinusoidal shaped cut at a depth substantially equal to the width of the sealing ring, and a third oscillating tool for plunging into the outer periphery of the workpiece to form a cut at a depth intersecting the cut of the second tool thereby forming a sinusoidal shaped sealing ring. The workpiece is a solid, cylindrical billet provided with a central hole formed therethrough. The spindle structure includes a hydraulic cylinder having an extendible and retractable rod provided with a threaded stud at one end thereof which passes through the hole in the billet and receives a nut thereon. The rod is selectively retracted to firmly retain the billet between the spindle structure and the nut for engagement with the first tool and the second tool. The billet may also be retained by a fixture or chuck.
In another aspect of the invention, a method is provided for machining a workpiece having an outer periphery and a face connected for rotation at the end of the driven spindle structure utilizing a slider arrangement for providing a multiple tool engagement with the workpiece and automatically coordinating the movement of the spindle structure and the slider arrangement. The improvement resides in the steps of (a) providing the workpiece in the form of a solid substantially cylindrical billet having retaining structure formed therein; (b) using at least one tool for rough cutting and finishing the outer periphery of the billet to a sinusoidal shape while the billet is attached to the spindle structure; (c) using another tool to form a sinusoidal shaped cut in the face of the billet at a depth substantially equal to the width of the sealing ring; and (d) using yet another tool to form a cut in the outer diameter of the billet at a depth intersecting the cut of the face cutting tool, thereby forming a sinusoidal shaped sealing ring. The method includes the step of removing the formed sealing ring from the billet. The method filer includes the steps of repeating (a) through (d) to remove the desired number of formed sealing rings from the billet. In addition, the method also includes the steps of (f) retaining the remaining billet and (g) retrieving the billet and repeating the steps (a) through (e) to form sing rings of a smaller outer periphery.
In yet another aspect of the invention, a machine tool is provided for forming sinusoidal shaped sealing rings form a solid, cylindrical billet having an outer diameter, a face and a hole formed centrally therein. The machine tool includes a spindle structure mounted for rotation about a first axial axis upon which the billet is removably attached. A slider arrangement is mounted for axial movement about a second axial axis parallel to the first axial axis and has a first portion and a second portion fixed adjacent thereto. The first portion is movably mounted along a radial axis generally perpendicular to the first and second axial axes and carries a parting tool and a finishing tool, and the second portion carries a turning tool and a trepan tool. A control device coordinates the movement of the spindle structure and the slider arrangement along the axial and radial axes such that, in sequence, the turning tool is engaged with the outer diameter of the billet to rough form a sinusoidal shape, the finishi
Andrus Sceales Starke & Sawall LLP
Hydra-Seal, Inc.
Tsai Henry
LandOfFree
Apparatus and method for forming sealing rings does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for forming sealing rings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for forming sealing rings will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2596884