This invention relates generally to a method and apparatus for aligning two components joined together. More specifically, this invention relates to a method and apparatus for very quickly and accurately aligning two components joined together, which finds particular utility in the quick and accurate joining of a sonotrode to a booster in an ultrasonic machine tool.

BACKGROUND OF THE INVENTION Ultrasonic machining is a well known machining process whereby the surface of a workpiece is abraded by a grit contained in a slurry circulated between the workpiece surface and a vibrating tool adjacent thereto, vibrating at frequencies above the audible range, typically within the range 19,500 to 20,500 cycles per second. The abrading tool face is usually provided with a three-dimensional form, while a negative compliment thereof is machined onto the workpiece surface. This process finds particular utility in its ability to work difficult materials, such as glass, ceramics, calcined or vitrified refractory materials and hard and/or brittle metals, which are not susceptible to machining by any other traditional technique, or even such nontraditional techniques such as electrical discharge machining, electro-chemical machining or the like. The usage of ultrasonic machining must necessarily be limited to the working of small areas, as the maximum power of available ultrasonic transducers does not permit the use of large tools. In particular, the maximum frontal area of the tool and workpiece are limited to about a three inch diameter, which is the approximate power limit of available tools.

The use of ultrasonic machining for production applications may also be limited by the time required to mount and\or change the tool assembly and align the tool with the workpiece. Typical tool changing times run from 30 minutes tc an hour. This is because the tool assembly itself, that is the transducer, booster, fixturing plate and abrading tcc , referred to in the art as a sonotrode, must be carefully aligner to assure very accurate alignment of the components

and good tight attachments, and once the assembly is properly assembled, it must be very carefully mounted and aligned on the machine tool table so it will mate accurately with the workpiece mounting and accordingly the workpiece. In many applications where the abrading time may run for very short times, say 2 to 5 minutes, the 30 minute to one hour tool change over time renders the use of ultrasonic machining as economically unjustified for such short run jobs.

The transducer, booster and sonotrode are usually joined by drilling and tapping small holes at the center of the vertical axis thereof and then threading them together with a stud extending from one component to the other within the tapped holes. While this has been shown to be a good method of joining the components in that it provides a good tight union as necessary in the ultrasonic assembly, it has resulted in problems in so far as repeated break-down and reassembly is concerned. This is because repeated break-down and reassembly causes the threaded interfaces to wear with time so the the fit-up becomes somewhat loose, and in particular, the rotational alignment suffers. That is to say, every time a given component is threaded onto another where it had been threaded before, it tends to turn a slight amount past the point where it tightened the time before. With repeated break-down and reassembly, therefore, the one component tends to gradually turn with respect to its original position. Accordingly, considerable time is expended in attempts tc properly realign all the components during a tool change operation.

It is obvious that one solution to the problem would be to provide an ultrasonic tool assembly for every abrading tool utilized. In that way, the machine operator would only need to change the tool assembly itself whenever an abrading tool, i.e. sonotrode, change is needed. However, transducers are very expensive pieces of equipment and it would be very unreasonable economically to maintain an entire transducer and booster for every sonotrode in inventory. Accordingly, it has become an economic necessity that whenever a change in tool is called for, that the tool assembly be broken down and the

replacement sonotrode be affixed to the previously used transducer and booster assembly. For most tool changes therefore, it is not necessary to change the transducer to booster connection, but the sonotrode to booster connection must usually be changed in order to effect the tool change.

SUMMARY AND OBJECTS OF THE INVENTION

This invention is predicated on the development of a method and apparatus for quickly and accurately aligning two components when being joined, utilizing preformed inserts positioned between mating V-grooves or conical recesses machined into the abutting faces of the joining components.

This method and apparatus finds particular utility in the more rapid and accurate alignment of components which are repeatedly broken-down and reassembles, such as boosters to sonotrodes in the assembly and reassembly of ultrasonic tool assemblies utilized in ultrasonic machine tools.

Accordingly, it is an object of this invention to provide a process and apparatus for quickly and accurately aligning two components when being joined together. It is another object of this invention to provide a method and apparatus for quickly and accurately aligning two components in the repeated reassembly thereof.

A further object of this invention is to provide a method and apparatus for quickly and accurately aligning sonotrodes to boosters as utilized in ultrasonic tool assemblies on ultrasonic machine tool during the repeated assembly thereof, assuring a good tight union.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a sectional side view of a typical sonotrode to booster connection illustrating the utilization of one embodiment of this invention before the two components are securely fastened together.

Figure 2 is identical to Figure 1 except that it illustrates the connection after the sonotrode and booster are securely fastened together.

Figure 3 is a top view of the booster shown in Figures 1 and 2 before the sonotrode is set thereon, and illustrates the spherical nature of the inserts utilized.

Figure 4 is a top view of a booster as shown in Figure 3 but illustrates the utilization of tubular inserts.

Figures 5, 6 and 7 are top views of boosters as shown in Figures 3 and 4 but illustrating different arrangements of V- grooves or conical depressions.

Figure 8 illustrates a few differing configurations for the deformable inserts that can be utilized with this invention.

DESCRIPTION OF THE INVENTION Reference to Figures 1 to 3 will illustrate one embodiment of this invention wherein sonotrode 10 is positioned over booster 12 prior to their being joined together. Booster 12 has a hole 14 extending through it axis for the full length thereof, while the bottom surface of sonotrode 10 is provided with a tapped hole 16 mating therewith. The flat abutting surfaces where sonotrode 10 will meet booster 12 are each provided with machined conical recesses 18, all of which have identical depths and configurations such that each conical recess 18 on the sonotrode 10 will mate exactly with a conical recess 18 on the booster 12. A spherical, deformable insert 20 is placed within each conical recess 18 in either the booster 12 or sonotrode 10 before the the other is positioned thereover, so that a spherical insert 20 is positioned between a mating pair of conical recesses 18 before the two components are joined together. The spherical and deformable inserts 20 must be larger enough to prevent the two flat faces of sonotrode 10 and booster 12 from coming into contact with each other before the sonotrode 10 is tightened onto booster 12, but must be sufficiently deformable and small enough to be deformed and thereby allow such contact permitting a good tight abutment when the two components are tightly secured together. Accordingly, when an elongated bolt 22 (Figure 2) is inserted through hole 14 and tightened into tapped hole 16. sonotrode 10 will be tightened down onto booster 12, the spherical inserts 20 cradled within the abutting conical recesses IS will maintain the proper alignment of sonotrode 10 on booster 12 until the two are tightly joined, as illustrated in Figure

3. It is apparent the the location and sizing of conical recesses 18 must be very carefully positioned when they are machined. Once they are in place, however, the assembly can be taken apart and rejoined repeatedly with virtually no effort being required to assure that the two components are properly aligned, as the deforming inserts 20 will maintain the alignment during the bolting operation.

Reference to Figures 5, 6 and 7 will illustrate other embodiments of this invention utilizing different arrangements for conical recesses 18, and the use of V-grooves 24 instead of conical recesses where the deformable insert can be short lengths of rod or tubing 26, or even spheres. In Figure 5 for example, provision is made for the utilization of four spherical inserts instead of three. Figures 6 and 7 show the same two arrangements but utilize rods or tubing within V- groove instead of spherical inserts within conical recesses. As shown in Figure 7 even the use of spheres 20 within a V- groove 24 is possible. Figure 8 illustrates several different forms of inserts that have been tested as alternatives to spheres and rods or tubing, and have been shown to be suitable.

In view of the above, it should be apparent that the configuration of the deformable inserts 20 is not important as long as they present a uniform contact within each recess or V-groove to bias them apart and keep the components aligned during the tightening operation, and have a section that will deform uniformly so that the proper alignment of components is maintained as they are tightened together.