BACKGROUND OF THE INVENTION A common task in making machines is to secure annular parts in such fashion that they are held securely in position, within very close tolerances. Annular parts, such as bearings, bushings and pressure seals, present a difficulty in that the part must be held so that it does not move radially or laterally. Radial movement is prevented by mounting the annular part in a housing. Lateral movement along the axis of the annular part is prevented by providing a radially extending projection on the outer circumference of the annular part which projection mates with a similar recess in the inside circumference of the housing. The housing is commonly in two pieces allowing the annular part to be placed in position in a groove in the first side of the housing, the second side then being bolted to the first side, securing the annular part in place in the housing. The two sides of the housing may be separated radially, perpendicular to the axis of the annular part, or laterally, parallel to the axis of the annular part.

The crankshaft bearings of an internal combustion engine are an example of the use of a split two-part housing.

There is a first half of a circular hole cast into the bottom of the engine block, the second half of the hole being provided by a bearing cap which is bolted to the engine block, thereby forming the housing hole which retains the bearing.

The bearing is prevented from moving laterally by a projection on the bearing which mates with a groove or notch in the

engine block.

A milling machine is most often used to line bore the housing. The milling machine has a shaft attached to a spinning head at one end and an outrigger support bearing at the opposite end. A cutting tool is mounted a at a mid-point of the shaft. In the case of the crankshaft example, the bearing cap is bolted in position to the engine block, forming the rough hole, with the shaft of the milling machine extending through the rough bearing holes. The engine block is moved along the shaft so that the mid-mounted cutting tool can pass through the axis of all the bearing holes, thereby finishing the rough holes. Using this method, the shaft of the milling machine must be twice as long as the engine block.

The set-up for line boring is cumbersome and time consuming as the two parts of the housing must be assembled in order to bore the holes. This makes the process expensive. The machine tool operator using this method must be highly skilled, as constant measuring and adjustment is necessary in order to produce satisfactory results. There is always the risk of human error.

This method is generally satisfactory, however it presents problems in manufacture, especially when the housing must be cut and machined at some distance from the head of the milling machine. The longer the shaft must be, the more vibration there will be and the accuracy of the cut will be reduced. Another problem is cutting tool wear. As the cutter moves along from housing to housing the tool wears and becomes slightly smaller.

These problems are accentuated when manufacturing multi-stage pumps, where the distance from the head of the milling machine to the cutting tool can be five to ten feet or more. It is virtually impossible to standardize the housing

size within the required tolerances. The annular seals must then be machined to fit the housings between each different stage. Individual manuals are then needed for each machine giving the dimensions for each housing and seal, in order to allow the proper size replacement seals to selected for each housing. This is a very time consuming and expensive process, and leads to further expense as replacement parts cannot be standardized. Again in such multi-stage pumps, the closer the tolerance of the seals, the more efficient the pump since there is less leakage between stages. In such pumps, the central rotating shaft runs inside the seals, with a gap of approximately six thousandths of an inch between the shaft and the seal. This gap could be reduced if the tolerances between the seal and the housing were smaller, and efficiency would be improved as leakage between the shaft and seal is reduced.

Similarly, leakage between the seal and the housing would also be reduced, further increasing efficiency. The set-up for boring these large pumps is particularly cumbersome and time consuming, as the parts are very large.

Those skilled in the art will recognize that an improved system and method of securing annular parts would have applications in many different machines where similar problems of manufacture occur. Many of the manufacturing problems noted above could be overcome by a system designed so that the housing could be machined by a cutting tool having the driving head located close to the cutter. It would also be a particular advantage if the housing parts did not have to be assembled and then disassembled during the process.

SUMMARY OF THE INVENTION It is therefore the object of the present invention to provide a system and method for securing annular parts in machines that is faster, easier and cheaper to manufacture

than present systems.

It is the further object of the present invention to provide such a system and method that provides for increased accuracy of machining, allowing reduced clearances between parts of the machine.

It is the further object of the present invention to provide such a system and method where the housing for the annular part could be machined by a cutting tool having the driving head located close to the cutter.

The present invention provides a system for securing annular parts comprising a two part housing, each said part having an outer surface integral with, or attachable to, a machine, and an inner surface for securing an annular member and each said part defining one half of an annular groove on the inner surface thereof such that when the two parts are fastened together, the annular groove is on the inner surface of the housing; and an annular member having an outer surface mating with said annular groove; wherein said groove has a cross-section that is an arc of a circle, said circle having a radius less than the radius of said annular member.

The present invention further provides a method of securing annular parts comprising the steps of securing one part, the first part, of a two part housing to a machine table; using a ball-nose cutter having a radius less than the radius of the annular part that is to be secured, said ball- nose cutter held in the spindle of a computer controlled milling machine, cutting a first groove in the inner surface of the first part of the housing, said first groove being one half of the total groove that will result when the two parts of the housing are fastened together; repeating the two steps above for the second part of the housing; machining the outer

surface of the annular part that is to be secured so that said outer surface mates with said total groove; placing said annular part into the groove, being one half of the total groove, in one part of the housing; and fastening the two parts of the housing together.

Recent innovations in cutting tools have made possible this new system. A computer controlled milling machine may be positioned over a workpiece of essentially any size. Such a milling machine uses computer control to move the cutter through any defined path in three dimensions, which has not previously been possible. The computer control greatly reduces the possibility of human error.

Thus a cutter may be programmed to travel in a near perfect circle, or semicircle. A ball-nose cutter travelling in a semi-circle will leave a groove that has the cross- section of an arc with a radius equal to the radius of the ball-nose cutter. Thus the two parts of a split housing may be grooved separately so that when they are joined, a very accurate circular groove will be left on the inner surface of the housing which groove may be mated to an annular part with a circumferential surface of the same radius.

When the radius of the groove is less than the radius of the annular part, the annular part will be held rigidly in place, as the annular part cannot twist. The improved accuracy allows for reduced tolerances. Thus where the annular part is a seal, the shaft may pass through the center hole of the seal without touching the seal, while leaving a very small gap. This increases the efficiency of the seal while reducing wear of the seal. Similarly, the clearance between the housing and the seal may be reduced, again increasing the efficiency of the seal. If even further efficiency is desired, a further groove or grooves for an O-

ring seal may be machined into the outer surface of the seal, such that the O-ring will bear on the inner surface of the groove in the housing.

Where a longer annular part, such as a cylinder, is to be secured in the housing, a series of circular grooves could be cut in the housing, with the outer surface of the cylinder machined to mate with the series of grooves.

Alternatively, the ball-nose cutter could be programmed to cut the series of grooves so close together that a groove is formed that is substantially flat in the middle portion, with side-walls having the radius of the ball-nose cutter.

In yet a further embodiment of the invention, there is provided a system for securing annular parts comprising a two part housing having an inner surface for securing an annular component, one half of said inner surface being defined within one of said parts and the other half of said inner surface being defined within the other of said parts, said one half of said inner surface being an out of round configuration and said other half of said inner surface being an out of round configuration.

In still yet a further embodiment of the invention, there is provided a method of securing annular parts within a housing, said annular parts being used for holding a circular member rotating within said annular parts, said method comprising machining a first out of round configuration on the outside of said annular parts, machining a second out of round configuration on the inside of said housing holding said annular parts, said first out of round surface on said inside of said housing mating with said second out of round configuration on said outside of said annular parts.

DESCRIPTION OF THE DRAWINGS While the invention is claimed in the concluding portions hereof, preferred embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagrams where like parts in each of the several diagrams are labelled with like numbers, and where: Figure 1 shows a front and a side plane view of an embodiment of the invention; Figure 2 is a perspective view of the embodiment of the invention of Figure 1; Figure 3 is a cross-section view of an alternate embodiment of the invention; Figure 4 is a cross-section view of an embodiment of the invention for use on long, cylindrical parts; Figure 5 is a cross-section view of an embodiment of the invention including O-ring seals; Figure 6 is an end view showing a preferred method for making the grooves to secure the annular parts; Figures 7A and 7B are front and side views of an annular component according to the invention having a circular configuration wherein the component may otherwise rotate within a housing used to hold the component; Figures 8A, 8B and 8C are front, side and bottom views of an annular component according to a further aspect of the invention in which the shape is more elliptical and out of

round thereby preventing rotation within a housing; and Figures 9A and 9B are front and side views of a housing used to hold the annular component of Figures 8A, 8B and 8C thereby preventing rotation of the component within the housing.

DETAILED DESCRIPTION OF THE EMBODIMENT The invention is a system for securing annular parts comprising a two part housing, each said part having an outer surface integral with, or attachable to, a machine, and an inner surface for securing an annular member and each said part defining one half of an annular groove on the inner surface thereof such that when the two parts are fastened together, the annular groove is on the inner surface of the housing; and an annular member having an outer surface mating with said annular groove; wherein said groove has a cross- section that is an arc of a circle, said circle having a radius less than the radius of said annular member.

Figures 1 and 2 show one preferred embodiment of the invention. Top housing 1 and bottom housing 2 are held together by bolts 3. Groove 4 has a radius R1 which is less than the radius R2 of the annular part 5. Annular part 5 can be a bearing, seal or any required part. The outer surface 6 of the annular part 5 is machined to mate with the groove 4.

Figure 3 shows an alternate embodiment where the housing is split along the perimeter of the groove. Right housing 7 and left housing 8 are fastened together by bolts 3 to form the groove 4, which has a radius R1 which is less than the radius R2 of the annular part 5, and which secures the annular part 5 in the housing.

There are two critical points to make the system work. First, for an annular part 5 having a length L less than twice its radius R2, the radius R1 of the cross-section of the groove 4 must be less than the radius R2 of the annular part 5. This feature is what prevents the annular part 5 from twisting in the groove 4. It is contemplated that, for best results in most applications, R1 should be less than. 75 R2.

For an annular part 5 having a length L greater than twice its radius R2, this is not a critical factor, as the annular part will be held as in Figure 4, with a plurality of grooves 4, and thereby prevented from twisting.

Second, one half of the groove 4 must be defined by each of the two housing parts. In either the embodiment of Figure 1 or Figure 2, one half of the groove 4 is defined in each part of the housing. If more of the groove 4 is in one part than the other, the groove 4 halves will not meet at a tangent to the groove 4, and the annular part 5 will not go into the groove in the part of the housing which defines more than one half of the groove. It will be noted that in the embodiment of Figure 1, each part of the housing defines a groove that is a half circle, while in Figure 2, each part of the housing defines a groove that is a circle and is one half of the total groove.

Figure 4 shows an embodiment of the invention for use to secure a long annular part 20. Long top housing 9 and long bottom housing 10 define a plurality of grooves 4. In this embodiment the length L of the annular part 5 is greater than twice the radius R2 of the long annular part 20, and the radius R2 of the grooves 4 is not critical.

Figure 5 shows an embodiment of the invention further including two O-rings 11 in O-ring grooves 12, for increased sealing efficiency.

The present invention further provides a method of securing annular parts comprising the steps of securing one part, the first part, of a two part housing to a machine table; using a ball-nose cutter having a radius less than the radius of the annular part that is to be secured, said ball- nose cutter held in the spindle of a computer controlled milling machine, cutting a first groove in the inner surface of the first part of the housing, said first groove being one half of the total groove that will result when the two parts of the housing are fastened together, which total groove has a cross-section that is an arc of a circle, said circle having a radius less than the radius of the annular part that is to be secured; repeating the two steps above for the second part of the housing; machining the outer surface of the annular part that is to be secured so that said outer surface mates with said total groove; placing said annular part into the groove, being one half of the total groove, in one part of the housing; and fastening the two parts of the housing together.

Figure 6 shows this method in use to secure seals in a multi-stage pump. Pump half 13 is mounted to a machine table 14, which table 14 is movable in the X-axis as shown, and which movement is controlled by a computer. Ball-nose cutter 15 is held in the end of the spindle 16 in the head of a milling machine 17 which head 17 is movable in the Y-axis as shown, and which movement is controlled by a computer. The radius R3 of the ball-nose cutter 15 is substantially less than the radius R4 of the bore hole 18 which will be occupied by the seal. The computer coordinates the movements of the machine table 14 in the X-axis and head 17 in the Y-axis so that the ball-nose cutter moves in a semicircle around the inside of the housing 19 which is an integral part of the pump half 13, leaving a groove whose cross-section is the arc of a circle having the same radius as the ball-nose cutter 15.

This process is repeated for all necessary seal housings in

the first pump half 13.

The same procedure is applied to the opposite pump half, the seals that have been machined to mate with the grooves in the pump are placed into the grooves 4 in one pump half and the two halves are bolted together, securing the seals.

Figure 6 shows that the cutting tool, the ball nose cutter 15 is located very close to the workpiece, the pump half 13, greatly increasing the accuracy by reducing the vibration that is inherent in line boring, where the milling machine spindle must be twice as long as the piece being bored. It is also plain that the cutting tool, the ball-nose cutter 15, is readily accessible to check for wear and make any necessary changes. As well, the set-up is simple, as the two parts of the housing can be cut while apart, doing away with the assembly and dis-assembly needed for line boring.

The computer control of the custom process greatly reduces the possibility of human error.

A further embodiment of the invention is contemplated with regards to Figures 7,8 and 9. An annular component generally illustrated at 700 in accordance with the teachings of the invention has a circular outer circumference 701. The annular component 700 is held within a housing (not shown) which has a similar circular inside configuration.

Means by way of a protuberance in the housing or similar restraint device is required to prevent the annular component from rotating within the housing about its axis.

Reference is now made to Figures 8A through 8C where the annular component generally illustrated at 800 has an outer perimeter 801 which is non-circular in configuration, being more closely resembling an ellipsoid type shape although

other out of round configurations are contemplated. The annular component may be made in a one-piece configuration or split along the plane C running through its center line.

The housing to hold the annular component is generally illustrated at 900 in Figures 9A and 9B. The housing 900 has a base portion 901 and a top half 902. The inside 903 of the housing 900 will be formed with the same configuration as the perimeter of the annular component 800 thereby allowing the annular component 800 to be securely held within the housing 900.

In operation, as the shaft (not illustrated) or other circular object passes through the annular component 800 and is rotated, there will be a tendency for the annular component 800 to rotate within the housing 900 about the axis of rotation of the shaft. However, the out of round configuration of the outside of the annular component 800 will prevent such rotation and contribute to the stability of the annular component 800 within the housing 900.

Thus it can be seen that the invention accomplishes all of its stated objectives. The foregoing is considered as illustrative only of the principles of the invention.

Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.