Apparatus for forming non-circular workpieces

An apparatus for forming non-circular workpieces including a rotatable workpiece carrying element which is laterally displaceable as it rotates to form the desired non-circular workpiece profile. The workpiece carrying element has three cam surfaces at least two of which have a non-circular profile, each bearing against fixed roller bearings to guide the workpiece against a fixed cutting surface to form the desired workpiece profile. The apparatus also is utilized to form at least the two non-circular profile cam surfaces.

BACKGROUND OF THE INVENTION 
The invention relates to an apparatus for forming non-circular surfaces on 
workpieces and more particularly to an apparatus having a workpiece 
carrying element on which is secured the workpiece and which is driven in 
rotation while being able to move laterally in all directions with respect 
to its axis of rotation to form the desired workpiece profile. 
The apparatus includes the workpiece carrying element which is maintained 
in contact, by means of three cams, with three roller bearings the axes of 
which are stationary to the operation of the rotating carrying element. At 
least two of the cams have a non-circular profile each of which is 
maintained, during the rotation of the workpiece carrying element, in 
contact with its respective roller bearing to guide the lateral or 
translational movement of the workpiece as it rotates. The workpiece is in 
contact with a fixed cutting tool which acts thereon as it is rotated and 
translated to cause the tool to cut the desired non-circular surface on 
the workpiece. 
The apparatus also is utilized with one of the three cams having a circular 
profile for making one or both of the other two non-circular profile cams. 
SUMMARY OF THE INVENTION 
The present invention provides an apparatus for making non-circular 
surfaces on workpieces, which apparatus has at least two non-circular 
profile cams and which apparatus also may be utilized to form the 
non-circular profile cams for a predetermined desired workpiece profile. 
The apparatus includes a workpiece carrying element which includes three 
cams each bearing against a fixed support roller. In operation, one cam is 
circular while the other two cams have a non-circular profile such that a 
workpiece secured to the workpiece carrying element is driven laterally in 
the desired profile as it is rotated against a fixed cutting tool to form 
the desired non-circular surface on the workpiece. To form the two 
non-circular cam surfaces for a particular desired workpiece profile, one 
cam is replaced by a oversized cam member to be formed into a non-circular 
profile shaping cam. The second non-circular profile cam is replaced by a 
circular member while the shaping cam is being formed. The roller for the 
shaping cam is replaced by a grinding wheel or abrasive strip which is 
driven against the oversized member. The stationary cutting tool is 
replaced by a stationary guide which is guided on a template surface 
having a reverse or inside out complementary shape to the desired 
workpiece profile. The apparatus is then operated to rotate the carrying 
element and the biased abrasive strip or cutter cuts the oversize member 
until the template has come into constant contact with the guide which 
forms the proper profile shaping cam. Once the shaping cam is fabricated a 
second complementary cam is then fabricated, but without the template and 
guide. The shaping cam roller is replaced and The circular cam is replaced 
by an oversize cam member. The second roller is also replaced by an 
abrasive strip or grinder biased to cut away the member until it also has 
the proper profile with each of the other cams now in constant contact 
with their respective rollers. The shaping and complementary cams now are 
shaped to provide the desired workpiece profiles on the apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As indicated above, the invention is concerned both with an apparatus for 
forming a non-circular profile on workpieces mounted on a rotating 
workpiece carrying element guided by three cam surfaces and the formation 
of the profiled cam surfaces to form a particular desired non-circular 
workpiece profile. 
Referring now to FIGS. 1 through 3, the workpiece forming apparatus of the 
invention is designated generally at 100. The forming apparatus 100 
includes a head stock 1 in which a quill 3 is rotatably mounted, by means 
of a plurality of roller bearings 2. The quill 3 includes a pulley 4 
fixedly mounted thereto which may be driven by a belt and motor (not 
illustrated). A workpiece 5 to have a non-circular profile formed thereon 
is removably secured on a chuck 6 by a gripping rod 7 traversing the quill 
3. The chuck 6 is mounted at one end of a workpiece carrying element or 
sleeve 8 which has formed on its opposite end, a flange 8a having a 
circular profiled surface. 
The flange 8a of the element 8 is secured between a pair of rings 9 and 10. 
The ring 9 is maintained angularly rigid by means of a plurality of 
rollers 11 (only one of which is shown) with a flange 12 fixedly engaged 
on a front end of the quill 3. The second ring 10 is maintained in 
engagement with the flange 8a by four stay-rods 13 (one of which is 
visible in FIG. 3) which maintain the ring 10 angularly rigid with the 
quill 3. The stay-rods 13 pass through the flange 8a through circular 
openings 14, which openings have a larger diameter than the outer diameter 
of the rods, so that the rods pass therethrough with lateral clearance 
therefrom. The flange 8a is maintained angularly rigid with the ring 9 by 
a plurality of rollers 15 (only one of which is shown). 
The ring 9 and the flange 12 have a plurality of V-shaped grooves on their 
adjacent surfaces for receiving the rollers 11 which are perpendicular to 
the plane of FIG. 3 of the drawing, which permits the ring 9 to move 
laterally in one direction. The ring 9 has a plurality of openings 16 
through which the stay-rods 13 pass, each of which openings 16 is 
elongated in the direction perpendicular to the plane of FIG. 3. The 
flange 8a and the ring 9 have a plurality of grooves (not numbered) in 
their adjacent surfaces to maintain the rollers 15, which grooves are 
parallel to the plane of FIG. 3. The rollers 15 and grooves allow the 
flange 8a to move perpendicular to the direction of the movement of the 
ring 9 with respect to the flange 12. 
The arrangement of the rings 9 and 10, flanges 8a and 12 and the openings 
and rollers provided therein, form a cross-shaped slide way for the 
workpiece carrying element 8. The slide way allows the workpiece carrying 
element or sleeve 8 a degree of movement in all lateral directions while 
it is being rigidly rotated with the quill 3. The ring 10 and the flange 
8a include an abutting bearing 17 interposed therebetween, against which 
the stay-rods 13 are axially tightened. 
The sleeve 8 also carries a pair of interchangeable profiled cams 18 and 19 
which are secured to the sleeve or workpiece carrying element 8 by four 
screws 20 screwed in holes 140 of this element 8 (FIG. 3 and 7B). The 
non-circular profile of the cams 18 and 19 may be formed on the forming 
apparatus 100 as discussed with respect to the FIGS. 4-6. The profiles of 
the cams 18 and 19 are somewhat exaggerated in FIG. 1 to illustrate their 
non-circular profiles. FIGS. 7A-7D illustrate, however, substantially the 
exact profile of a particular workpiece 5 to be formed and the circular 
cam profile 8a and the profiled cams 18 and 19 to form the workpiece 5 
non-circular surface. 
The non-circular profile of the two cams 18 and 19 and of the cam or 
bearing surface formed by the flange 8a of the sleeve 8, as well as their 
relative position, are such that during the rotation of the quill 3, each 
of the three cams constantly will remain in contact with respective fixed 
rollers 21, 22 and 23. Each of the rollers 21, 22 and 23 are rotatably 
mounted in a fixed position on the front face of the head stock 1. The 
three rollers are radially fixed during operation of the workpiece forming 
apparatus 100, but the radial position of the roller 23 is adjustable by 
means of an eccentric head 24a of a screw 24 to permit for compensation of 
manufacturing tolerances and wear of the apparatus. 
The forming of a non-circular surface such as, for example, a surface 25 of 
the workpiece 5 is obtained by rotating the workpiece on the chuck 6 
against a stationary cutter 26. The workpiece 5 is rotated on the chuck 6 
by means of the pulley 4 rotating the quill 3 and the proper radial 
displacement of the workpiece surface 25 is effected by the cam surfaces 
8a, 18 and 19 rotating against their fixed rollers 21-23, which determine 
at each angular position of the quill 3 a given radial position for the 
sleeve 8 and consequently for the workpiece 5. The stationary cutting tool 
or cutter 26 could be replaced by a grinding wheel or by a milling cutter, 
if desired. 
In operation the workpiece forming apparatus 100 is rotated by the drive 
pulley 4 on the rotating quill 3. The spindle 8 is rotatably keyed through 
the drive pins 13, but is allowed to flow relative to the rotational axis 
of the quill 3 because of the rollers 11 and 15 keyed between the flange 
8a, ring 9 and flange 12. Thus the spindle 8 will shift or rock due to the 
profile of the cams 18 and 19 as the quill 3 rotates. The lateral movement 
of the spindle 8 is the equivalent of a rocking movement around an axis 
parallel to the axis of the spindle 8 passing through the contact point 
between the element or cam 8a and the roller 21. In other words, if the 
spindle 8 was not rotating on itself, the bearing of the cam 8a against 
the roller 21 could be replaced by an articulation of the spindle on a 
shaft the axis of which would pass through the contact point between the 
cam 8a and the roller bearing 21. In this rocking or shifting movement, it 
should be noted that there is a very slight lateral movement of the 
contact point between the cam 8a and the roller 21, but such movement is 
substantially insignificant. 
The cam 18 bearing against the roller 22 is a shaping cam which maintains 
the proper lateral position of the spindle 8 as it rotates, which 
determines the shape of the non-circular surface formed. The cam 19 is a 
complementary cam which maintains the cam 18 bearing continuously against 
its roller 22. The mechanical equivalent of the cam 19 is essentially a 
spring biased against the spindle 8 for urging the cam 18 against the 
roller 22. The shape of the cam 19 is a direct function of the shape of 
the cam 18 and is such that whatever the lateral position of the spindle 8 
may be, the cam surface 8a is in contact with roller 21 and the shaping 
cam 18 is in contact with its roller 22. The complementary cam 19 is also 
in contact with its roller 23. 
Attempts have been made to determine theoretically the shape of the cam 18 
for a particular non-circular workpiece profile. Some attempts at 
mathmetically calculating the shape of the cam 18 have been attempted by 
computerized analysis, but have not yet succeeded. Therefore, at this time 
the only practical way of manufacturing cam 18 is on the workpiece forming 
apparatus 100 itself. Although the mathmetical analysis of the shaping 
process has not yet been fruitful, the cams 18 and 19 which are formed on 
the workpiece forming apparatus 100 operate in the desired manner. 
One such set of cams is shown in FIGS. 7A-7D which were formed in the 
matter set forth hereinafter in describing FIGS. 4-6. In this respect the 
cams 18 and 19 are formed on the apparatus 100' as described starting with 
FIG. 4. 
To make the shaping cam 18, cam 18 is replaced on the sleeve 8 by a rough 
or unformed member 18' (FIG. 4) and the roller 22 will be replaced by an 
abrasive strap 27 rotating on a roller 28 located in place of the roller 
22 (FIG. 5). The diameter of the roller 28 will be slightly less than that 
of the roller 22 to compensate for the thickness of the abrasive strap 27. 
The cam 19 will be replaced by a circular cam 19'. The roller 23 will be 
released so that it is a radially moveable roller 23' and the screw 24 
will be replaced by means (not shown), which may be a lever submitted to 
the action of a spring carrying a roller which bear against the roller 
23', to exert a radial pressure, as shown by the arrow 29 (FIG. 4), 
against the moveable roller 23' to maintain it against the circular cam 
19'. 
The workpiece 5 will be replaced by a template 30 which represents the 
negative complementary or in side out shape of the surface 25 to be cut 
and the cutting tool 26 will be replaced by a stationary cam or template 
follower 31. 
The cam 18 is then formed from the rough cam 18' by operating the workpiece 
forming apparatus 100' while applying pressure on the roller 23' as shown 
by the arrow 29. This maintains the cam 8a in contact with its roller 21 
and the unformed or rough member 18' is contact with the abrasive strip 27 
which may be driven by a motor 34 to abraid or cut away the rough surface 
of the cam 18' until the template 30 bears continuously on the follower 31 
throughout the entire rotation of the sleeve 8 resulting in the finished 
cam 18. 
The workpiece forming apparatus 100' also may be utilized to make the cam 
19. As best illustrated in FIG. 6, the roller 22 (not shown) along with 
the formed cam 18 again will be mounted on the apparatus 100'. The 
circular cam 19' will be replaced by a rough or unformed cam member 19". 
The template 30 and the follower 31 will be eliminated or otherwise made 
inoperable. The roller 23 will be replaced by an abrasive strap 32 
rotating on a roller 33 of a diameter slightly less than roller 23 to 
compensate for the thickness of the abrasive strap 32, as previously 
described for the roller 28. A second motor 35 may be utilized to drive 
the abrasive strap 32, which may be an electric motor identical to motor 
34 or may be motor 34 with another coupling or gearing to accommodate the 
slightly offset position of the strap 32 from the strap 27. The abrasive 
straps 27 and 32 could also be replaced by grinding wheels if desired. The 
roller 33 will be biased against the rough cam member 19" by spring 36 or 
other equivalent means. The workpiece forming apparatus 100' is then 
operated as before until the abrasive strap 32 has cut away the surface of 
the rough member 19" such that the axis of the roller 33 is moved into the 
position corresponding concentrically to the center axis of the roller 23. 
The roller 23 is then replaced on the finished cam 19 and the workpiece 
forming apparatus 100 then may be utilized to cut the desired non-circular 
profiles on a sequence of workpieces 5, as previously described. 
Referring now to FIGS. 7A-7D, FIG. 7A illustrates one specific workpiece 5 
having a pair of non-circular surfaces 37 and 38, one or both of which may 
be formed utilizing the forming apparatus 100'. FIGS. 7B, 7C and 7D show 
the specific cam formations to form the surface 37 of the workpiece. 
FIG. 7B illustrates the spindle 8 having the circular cam profile 8a and 
the four openings 14. The shaping cam 18 and complementary cam 19 are 
illustrated in FIGS. 7D and 7C, respectively; however, these are 
interchangeable as noted above. The screws 20 pass through the holes 39. 
The complementary cam 19 has an outer irregular profile 40, while the 
shaping cam 18 has an outer irregular profile 41. As also mentioned above, 
the only known method for forming the profiles 40 and 41 on the cams 19 
and 18 for a desired workpiece surface is on the apparatus 100'. 
Modifications and variations of the present invention are possible in light 
of the above teachings. It is, therefore, to be understood that within the 
scope of the appended claims, the invention may be practiced otherwise 
then as specifically described.