U.S. patent number 3,635,069 [Application Number 04/874,242] was granted by the patent office on 1972-01-18 for drive mechanism for multiple plungers.
This patent grant is currently assigned to Dayton Reliable Tool & Mfg. Company. Invention is credited to Franklin C. Eickenhorst.
United States Patent |
3,635,069 |
Eickenhorst |
January 18, 1972 |
DRIVE MECHANISM FOR MULTIPLE PLUNGERS
Abstract
A massive power-driven rotary structure has a plurality of
circumferentially spaced pairs of dies to process a corresponding
plurality of workpieces on each of its revolutions. One die of each
pair is mounted on a longitudinally extending plunger and all of
the plungers are reciprocated in sequence by a fixed
circumferential cam track adjacent one end of the structure.
Inventors: |
Eickenhorst; Franklin C.
(Mason, OH) |
Assignee: |
Dayton Reliable Tool & Mfg.
Company (Dayton, OH)
|
Family
ID: |
25363301 |
Appl.
No.: |
04/874,242 |
Filed: |
November 5, 1969 |
Current U.S.
Class: |
72/345; 72/361;
72/349; 413/52 |
Current CPC
Class: |
B21D
22/08 (20130101); B30B 11/08 (20130101); B21D
51/26 (20130101) |
Current International
Class: |
B30B
11/02 (20060101); B30B 11/08 (20060101); B21D
22/00 (20060101); B21D 22/08 (20060101); B21D
51/26 (20060101); B21d 051/26 () |
Field of
Search: |
;113/7,120,115
;72/94,349,344-346,361 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Herbst; Richard J.
Claims
I claim:
1. In an apparatus of the character described, the combination
of:
a fixed structure;
a power-actuated rotary structure adjacent the fixed support
structure;
a plurality of longitudinally extending guideways mounted on the
rotary structure and spaced circumferentially thereof;
a corresponding plurality of longitudinally extending plungers
mounted in the guideways respectively, each of said plungers having
a working end and a trailing end;
fixed cam means on the fixed structure positioned concentrically of
the series of plungers and forming two opposite continuous cam
walls;
two follower means mounted on the trailing ends of the respective
plungers in moving contact with said two cam walls respectively,
said cam walls being shaped to reciprocate the plungers in said
guideways in the course of each revolution of the rotary
structure;
a corresponding plurality of first die means mounted on the leading
ends of the plungers respectively for movement therewith;
a corresponding plurality of second die means paired with the first
die means respectively and mounted on the rotary structure in
alignment with the first die means for cooperation therewith to
process successive workpieces;
means to feed successive workpieces to said pairs of dies;
means to remove the successive processed workpieces;
said guideways and corresponding plungers being of complementary
noncircular cross-sectional configuration to prevent rotation of
the plungers on the axes; and
a pair of cooperating engagement means incorporated in each of said
guideways in engagement with the periphery of the corresponding
plunger to oppose rotation of the plunger on its axis in opposite
rotary directions respectively,
said two-cooperating engagement means being preloaded against each
other to keep the plungers from rotating on their axes and in doing
so to minimize backlash between the plungers and the corresponding
guideways.
2. A combination as set forth in claim 1 in which each of said
plungers together with the corresponding followers, the
corresponding die means and the corresponding pair of engagement
means is removable as a unit to permit one unit to be substituted
for another.
3. A combination as set forth in claim 2 in which the pair of
cooperating engagement means of the unit comprises two guide
sleeves and in which the two guide sleeves are releasably attached
to the rotary structure to releasably anchor the unit thereto.
4. A combination as set forth in claim 3 which includes means on
the rotary structure to releasably engage the two sleeves of each
unit to cause relative rotation between the two sleeves to preload
the two sleeves against each other.
5. A combination as set forth in claim 1 in which one cooperating
engagement means of each pair is a sleeve of an inner
circumferential configuration complementary to the cross-sectional
configuration of the corresponding plungers,
said sleeve being rotatably preloaded relative to the other
engagement means to cooperate therewith to prevent rotation of the
corresponding plunger on its axis and to eliminate backlash between
the plunger and the corresponding guideway.
6. A combination as set forth in claim 5 in which each of said
plungers is formed with a plurality of longitudinal splines and
each of said engagement means has a plurality of longitudinal
spline means in engagement with the splines of the corresponding
plunger.
7. A combination as set forth in claim 5 in which each of said
sleeves is in the form of a ball nut, each of said ball nuts having
at least one spline means in the form of a longitudinal row of
balls.
8. A combination as set forth in claim 5 in which said two
continuous cam walls in cross section are precisely perpendicular
to the axis of rotation of the rotary structure;
in which the follower means on the trailing end of each plunger
comprises two rollers in contact with the two cam walls
respectively with the axis of rotation of each roller located
precisely at the intersection of two planes, one plane being
perpendicular to the axis of rotation of the rotary structure, the
other plane including the axis of rotation; and
in which one of said cooperating engagement means of each pair
serves as a stop against rotation of the plunger on its axis beyond
a given rotary position at which the axis of rotation of each
roller is precisely located at the intersection of the two
corresponding planes, the other engagement means of each pair
urging rotation of the corresponding plunger on its axis against
the stop to maintain the plunger at said given rotary position.
9. A combination as set forth in claim 1 in which the portion of
the rotary structure that includes the plurality of guideways is
surrounded by fixed support structure with a bearing interposed
between said portion and the surrounding fixed structure to
stabilize said portion to promote accuracy in the operation of the
pairs of die means.
10. In an apparatus of the character described wherein a
cylindrical cam body with a transverse end wall is first mounted
with its cylindrical wall in a seat of a rotary holder, then a
plunger enters the cylindrical can body to cooperate with die means
for processing the can body and, finally, the plunger is withdrawn
to leave the processed can body in the seat,
the improvement comprising:
a commutator united with the holder to rotate therewith, said
commutator being in communication with a vacuum source and a
compressed air source, fluid passage means controlled by the
commutator to create a vacuum in said seat adjacent the cylindrical
can body to hold the can body in the seat while the plunger enters
the can body and subsequently to create a vacuum in the seat to
hold the can body on the seat to facilitate disengagement of the
plunger from the can body when the plunger is withdrawn from the
can body; and
fluid passage means controlled by the commutator to discharge
compressed air into the can body through the plunger to further
facilitate disengagement of the plunger from the can body when the
plunger is withdrawn from the can body.
11. An improvement as set forth in claim 10 in which the commutator
includes fluid passage means to supply lubricant to moving parts
that rotate with the holder.
12. A combination as set forth in claim 1 which includes adjustable
means to tighten one of said two follower means against the
corresponding cam wall to preload the two follower means for the
elimination of backlash.
13. A combination as set forth in claim 1 in which the two follower
means on the trailing end of each plunger comprises two rollers in
contact with the two cam walls respectively;
in which each of the pairs of cooperating engagement means on each
of said guideways comprises two guide sleeves embracing the
corresponding plunger,
one of the two guide sleeves being held against rotation in a given
rotary direction at a given rotary position,
the other of said two guide sleeves being adjustable to urge
rotation of the plunger in said given rotary direction against the
resistance of the one guide sleeve whereby to place the plunger at
a given rotary position corresponding to the given rotary position
of one sleeve,
said given rotary position of the plunger placing the axis of
rotation of each of said two rollers precisely at the intersection
of two planes, one plane being perpendicular to the axis of
rotation of the rotary structure, the other plane including the
axis of rotation.
Description
BACKGROUND OF THE INVENTION
The invention is directed to certain problems that are encountered
in designing a mechanism for the mass processing of workpieces by
cooperating dies where die-operating forces of relatively high
magnitude are required coupled with the requirement for a high
degree of accuracy in the operation of the dies. If high-magnitude
actuating forces are required such a mechanism is necessarily
relatively heavy and one problem is to obtain a high-production
rate by means of such a massive apparatus.
Another problem arises from the fact that a high rate of production
with a relatively massive mechanism involves inertia forces of high
magnitude that make it difficult to operate the mechanism with
sufficient speed for an economically high rate of hourly
production.
A further problem to be taken into consideration arises from the
desirability of such a massive high-speed apparatus to be versatile
for the processing of a wide range of workpieces to justify the
high-investment cost, it being especially important to minimize the
downtime required for change over from one run of workpieces to a
run of different workpieces.
Another problem to which the preferred embodiment of the invention
is specifically directed is the problem of arranging a high-speed
production mechanism which will handle extremely flimsy workpieces
such as workpieces in the form of exceedingly thin cylindrical
shells of aluminum alloy.
As will be explained, other problems pertinent to the invention
arises from the use of a massive power-driven rotary structure
having a plurality of pairs of dies that operate in sequence in the
course of each revolution of the structures.
SUMMARY OF THE INVENTION
The preferred embodiment of the invention employs a power-actuated
massive rotary structure of substantial axial dimension with a
plurality of pairs of dies circumferentially spaced thereon for
operation in sequence on each revolution of the structure. One die
of each pair of dies is fixedly mounted on the rotary structure and
the other die of the pair is mounted on a longitudinally extending
plunger which reciprocates in a corresponding longitudinal guideway
on the rotary structure and each of the plungers is provided with
followers that cooperate with a fixed cam track adjacent one end of
the rotary structure. In the initial embodiment of the invention,
12 pairs of dies are actuated through their operating cycles on
each revolution of the rotary structure so that the rate of
production is 12 times the rate of rotation of the rotary
structure.
In contrast to a conventional punch press, the major part of the
mass of the working mechanism rotates continuously at a constant
rate and thus eliminating the necessity for repeatedly accelerating
and decelerating massive parts. The rotary structure that carries
the 12 pairs of dies serves as a flywheel and the only
reciprocating parts are the longitudinal plungers and the dies
thereon. It is apparent then that the invention solves the problem
of dealing with inertia forces. It is also apparent that the
invention solves the problem of achieving high production with a
massive mechanism since the plurality of circumferentially spaced
pairs of dies multiply the rate of production.
The problem of adapting such a high-speed mechanism for precise die
operations on flimsy thin-walled workpieces is solved largely by
employing vacuum means to releasably anchor the flimsy workpieces
at desired points in the operating cycle. In the preferred practice
of the invention further provision is made for supplying compressed
air between die parts and the workpieces to facilitate stripping of
the workpieces from the dies.
A further feature of the preferred practice of the invention is the
concept of employing commutator means for placing the rotary
structure in communication with a stationary vacuum source, a
stationary compressed air source and a stationary lubrication
source.
It has been found to be exceedingly difficult to put this basic
concept into commercial practice because actuating the
circumferentially spaced dies in sequence by a fixed cam track may
result in self-destruction of the apparatus if the high-magnitude
forces are not properly controlled. The present embodiment of the
invention is based on the discovery of the complicated cause of
such self-destruction in prior mechanisms of this general type.
As will be explained, diversion of the high-magnitude operating
forces into destructive channels is avoided by specific provisions
to maintain with precision certain geometrical relationships which
have been discovered to be absolutely essential.
The features and advantages of the invention will be understood by
reference to the following detailed description and the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, which are to be regarded as merely
illustrative:
FIG. 1 is a perspective view of the presently preferred embodiment
of the invention;
FIG. 2 is a longitudinal axial sectional view of the
embodiment;
FIG. 3 is a more or less diagrammatic view showing how workpieces
are fed to the rotary structure at an input station and further
showing how the finished workpieces are removed at an output
station;
FIG. 4 is a diagrammatic view showing how the mechanisms at the
input and output stations are operatively connected with the rotary
structure for actuation thereby in synchronism therewith;
FIG. 5 is an enlarged fragmentary view partly in section and partly
in side elevation showing how a pair of dies close to process a
workpiece;
FIG. 6 is a similar view showing one die of the pair being
retracted after the workpiece is processed;
FIG. 7 is an enlarged fragmentary view partly in section and partly
in side elevation showing how one of the longitudinally extending
plungers is mounted on the rotary structure and is operated by a
stationary cam track;
FIGS. 8, 9 and 10 are enlarged cross sections taken as indicated by
the lines 8--8, 9--9 and 10--10 respectively of FIG. 7;
FIG. 11 is a greatly enlarged fragmentary view partly in side
elevation and partly in section showing the two follower rollers on
a longitudinal plunger cooperating with the fixed cam track;
FIG. 12 is a sectional view showing how an eccentric stud may be
employed to rotatably adjust a ball sleeve for the purpose of
preloading a longitudinally extending plunger;
FIG. 13 is a perspective view of the eccentric stud;
FIG. 14 is an exploded perspective view showing how the
longitudinally extending plungers are mounted on the rotary
structure for quick removal and replacement;
FIG. 15 is a diagram showing a rotary disk of a commutator means
and indicating how the rotary disk is operatively related to the
main dial or turret that carries the successive workpieces;
FIG. 16 is a diagrammatic view of a complementary fixed disk of the
commutator that cooperates with the commutator shown in FIG.
15;
FIG. 17 is a side elevation partly in section, showing a cup-shaped
thin-walled aluminum workpiece, the bottom of which is to be dished
or domed inwardly by the dies of the apparatus; and
FIG. 18 is a similar fragmentary view of the workpiece showing the
result of the die operation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIGS. 1 and 2, the selected embodiment of the invention
has a hollow base, generally designated 20 and fixed support
structure on the base to journal the axial shaft 22 of a rotary
structure that carries the tooling for processing successive
workpieces. The fixed support structure includes an upright casting
24 that supports one end of the axial shaft 22 by means of a pair
of opposed thrust bearings 25. At the other end of the axial shaft
a pair of interconnected castings 26 and 28 support the shaft by
means of a pair of opposed thrust bearings 30 and a third thrust
bearing 32.
The rotary structure carries a plurality of circumferentially
spaced longitudinally extending plungers 34 which reciprocate in
corresponding guideways, generally designated 35, and which are
provided with pairs of follower rollers 36 and 38. The casting 28
which is bolted on the casting 30 is formed with a continuous cam
track 40 for cooperation with the follower rollers 36, 38 to
reciprocate the plungers 34, the cam track being in the form of a
circumferential rib of undulating configuration as required for
reciprocating the plungers. The circumferential series of guideways
35 for the plungers 34 are incorporated in a guideway casting 42
that is keyed to the axial shaft 22 and that has an outer
cylindrical surface 44 for cooperation with a surrounding bearing
44. The bearing 45 is mounted in an upright support casting 46 and
thus serves to stabilize the guideway casting 42 as required for
guidance of the plungers 35 with a high degree of precision.
As indicated in FIG. 5 a suitable die 48 is mounted on the outer
end of each plunger 34 and for this purpose each plunger has an end
socket to receive a shank portion 52 of the die with the shank
portion releasably secured by a diametrical dowel 54.
Also keyed to the axial shaft 22 is a tool support casting 55
having a radial flange 56 with a circumferential series of
apertures therein to receive a second set of dies or die
assemblies, generally designated 60, which are paired with the
first-mentioned dies 48 for cooperation therewith in the processing
of workpieces.
Also keyed to the axial shaft 22 is a main star wheel, generally
designated 62, which serves as a turret to carry the successive
workpieces while the workpieces are being processed by the dies. As
shown in FIG. 1, the star wheel 62 comprises two disks 64 with a
spacer collar 65 between the two disks, and with a hub member 66
abutting one of the disks. Each of the two disks 64 is of the
configuration of a star wheel that provides a circumferential
series of arcuate recesses 68, the recesses of the two disks being
paired to form seats to receive the successive workpieces. As
indicated in FIG. 1, the two disks 64 and the associated castings
are tied together by suitable bolts 70 and, as best shown in FIG.
5, a spacer block 72 and a cooperating bolt 74 tie the two disks 64
together in the region of each of the pairs of arcuate recesses 68
to cooperate with the pair of recesses to form the seat for a
workpiece.
As shown in FIG. 1, two components of a commutator means are
arranged at one end of the axial shaft 22. One of these components
is a commutator disk 75 that is keyed to the shaft for rotation
therewith and the other component is a fixed coaxial disk 76 that
is anchored to the end casting 24.
The axial shaft 22 carries a flywheel 77 which serves as a driven
pulley, the flywheel being connected by a belt with a drive pulley
78 on the shaft of a motor 79. The motor is housed by the hollow
base 20 along with a motor-driven vacuum pump 80 and a motor-driven
oil pump 81.
All of the various components on the axial shaft 22 are preloaded
to keep the various components in constant arcuate relationship
with each other. For this purpose an outer race of one of the two
thrust bearings 30 at one end of the shaft abuts a keeper ring 82
that is bolted to the support casting 26 and the outer race of the
second thrust bearing 30 bears against an inner circumferential
shoulder 83 of the casting. The axial shaft 22 is formed with a
circumferential shoulder 84 that abuts the inner race of the second
thrust bearing 30 and an oppositely facing circumferential shoulder
85 of the axial shaft abuts the inner race of the thrust bearing
32. The outer race of the thrust bearing 32 is retained by a keeper
ring 86 that is bolted to the casting 28. The spacer sleeve 88
embraces the shaft 22 between the inner race of the thrust bearing
32 and one end of the guideway casting 42 and a second spacer
sleeve 90 is interposed between the guideway casting and the hub
member 68 of the star wheel assembly 62. As heretofore stated the
star wheel assembly 62 abuts the tool support casting 55 and the
tool support casting in turn abuts the rotary commutator disk 75
which presses the second fixed commutator disk 76 against the
support casting 24.
For the purpose of exemplifying the utility of the illustrated
embodiment of the invention, the embodiment will be described as
adapted to process workpieces 92 of the character shown in FIG. 17.
Each workpiece 92 is a cup-shaped aluminum shell having a
circumferential wall 94 and a bottom wall 95. The workpiece is made
of a suitable aluminum alloy and after leaving the described
apparatus the workpiece is further processed to eventually become
the body of a beverage container. The workpiece is flimsy because
its walls are relatively thin, the cylindrical wall 94 being, for
example, as thin as 0.006 inch midway between the two ends of the
workpiece. The particular operation that is performed at a
high-rate per minute by the die means of the apparatus is the
transformance of the bottom wall 95 to the configuration shown in
FIG. 18 which may be described as an inwardly domed
configuration.
The die 48 on the leading end of each plunger 34 is dimensioned to
telescope into a workpiece 92 as shown in FIG. 5 and as also shown
in FIG. 5 the die 48 has a removable nose 96 that is releasably
secured by screws 98. The nose 96 has a concave-working face
conforming to the configuration of the bottom wall of the workpiece
that is shown in FIG. 18.
As shown in FIG. 5, the cooperating die assembly 60 includes a
retaining ring 100 that is releasably anchored by screws 102 to the
radial flange 56 of the tool support casting 55. The die assembly
60 further includes a doming die 104 that has a convex nose to
"dome" the bottom wall of the workpiece and has a shank by which it
is immobilized relative to the radial flange 56 of the tool support
casting in which the die assembly is mounted.
In the construction shown, the doming die 104 backs against a
spacer ring 105 which in turn backs against a circumferential
shoulder formed in a bore 106 of the radial flange 56. The degree
to which the bottom wall of the workpiece is domed is determined by
the length of the spacer sleeve. The doming die 104 is secured by a
tie rod 108 that is threaded into the shank portion of the die and
that extends outward through a tubular rod 110. The tubular rod 110
has a reduced end portion that extends into the bore 106 of the
radial flange 56 and has a circumferential shoulder 112 that abuts
the face of the radial flange. The tubular rod 110 further has an
outer end portion 114 of reduced diameter to receive an outer
collar 115 which is retained by a pair of nuts 116. A nut 118 on
the outer end of the tie rod 108 is tightened against the outer end
of the tubular rod to place the rod under tension and thus
immobilize the tubular rod and the die 104.
The die assembly 60 includes an annular die member 120 which, as
shown in FIG. 6, has an annular recess 122 to reshape the outer
radial region of the bottom wall 95 of the cup-shaped workpiece
just prior to the doming operation. The annular die member 120
further has a circumferential shoulder 124 to cooperate with an
inner circumferential stop shoulder 125 of the retaining ring 100.
For the purpose of urging the annular die member 120 outwardly of
the die assembly, four smooth pins 126 are mounted in four
corresponding bores 128 of the radial flange 56 and a collar 130
that is slidingly mounted on the tubular rod 110 is under pressure
by a suitable heavy coil spring 132 that backs against the outer
collar 115.
In the construction shown a thin cylindrical pressure pad 134 is
interposed between the doming die 104 and the annular die member
120 to strip finished workpieces from the annular die member and
for this purpose the thin pressure pad has a greater range of outer
movement than the annular die 120. The pressure pad 134 is integral
with a ring 135 which serves as a stop in cooperation with a radial
shoulder 136 of the die 104, and the ring is acted upon by a
plurality of light springs 138 that urge the pressure pad
outward.
A feature of the invention is the concept of employing a vacuum to
releasably anchor the successive workpieces 92 in the peripheral
seats of the main star wheel 62. As shown in FIG. 5 this purpose is
served by providing each of the spacer blocks 72 of the main star
wheel with a radial bore which communicates with a tube 140 which
in turn communicates with a suitable vacuum source by means
including the previously mentioned two commutator disks 75 and 76.
A further feature of this particular embodiment of the invention is
the concept of supplying compressed air to the various dies 48 to
strip the finished workpieces from the dies 48. As indicated in
FIG. 5, each die 48 is formed with an axial passage 142 which
receives compressed air from a corresponding tube 144.
As indicated in FIGS. 3 and 15, the successive workpieces are fed
to the main star wheel 62 by means including a smaller input star
wheel of the same general construction as the main star wheel, the
input star wheel having four circumferentially spaced peripheral
seats 146 to convey the workpieces to the 12 peripheral seats of
the main star wheel 62. As shown in FIG. 3 a plurality of rails 148
form a feed chute that leads to the input star wheel 145 and, in a
well-known manner, a screw member 150 extending longitudinally of
the chute is formed with a spiral groove 152 to control the
downwardly moving workpieces. The pitch angle of the spiral groove
152 progressively increases for the purpose of progressively
spreading the workpieces apart until the workpieces are spaced in
accord with the circumferential spacing of the seats 146 of the
input star wheel 145.
As indicated in FIG. 15 arcuate guard rails 154 extend under the
input star wheel to keep the workpieces in the seats 146 until the
workpieces reach the main star wheel 62. The main star wheel is
provided with additional arcuate guardrails 55 in the region of the
input star wheel to retain the successive workpieces 92 in their
seats on the main star wheel until a vacuum is developed at each
seat of the main star wheel to effectively retain the
workpieces.
Also associated with the main star wheel 62 is a smaller output
star wheel 156 having a series of four peripheral seats 158 for the
processed workpieces. Arcuate guardrails 160 in the region of the
output star wheel hold the workpieces in their seats in the main
star wheel after vacuums of the seats are terminated, the
guardrails keeping the processed workpieces in place until they
reach the output star wheel 56. Additional rails 162 retain the
finished workpieces in the seats 158 of the output star wheel and
provide a gravity chute 164 for a discharge of the finished
workpieces.
The input star wheel 145 and the output star wheel 156 are
operatively connected to the rotary structure by suitable gearing
and since the main star wheel 62 has 12 peripheral seats and each
of the smaller star wheels has only four peripheral seats, the two
star wheels are actuated at three times the r.p.m. of the larger
star wheel.
Suitable gearing for this purpose is shown diagrammatically in FIG.
4 where a large gear 165 unitary with the rotary structure serves
as a drive gear in mesh with a smaller driven gear 166. The driven
gear 166 meshes with an idler pinion 168 which in turn meshes with
a gear 170 on a shaft 172 that carries the output star wheel 156.
In like manner, the driven gear 166 meshes with an idler gear 174
which in turn meshes with a gear 178 on a counter shaft 179 that is
shown in FIG. 2. The shaft 179 drives the input star wheel 145 as
shown in FIG. 1. In addition, the shaft 179 carries a gear 180
which acts through two gears 182 and 183 to drive the previously
described input screw member 150.
The invention includes the discovery of the vital fact, heretofore
unknown, that unless certain critical relationships are precisely
maintained, the various plungers 34 are subject to disruptive
forces that either wreck the means for mounting follower rollers on
the plungers or rupture the fixed cam track 40. These relationships
are: first, that the opposite faces of the cam track 40 be in cross
section precisely perpendicular to the axis of rotation of the
shaft 22; second, that the axis of rotation of each of the two
follower rollers 36 and 38 lie precisely at the intersection of two
planes, one plane being perpendicular to the axis of rotation of
the shaft 22 and the other plane being a radial plane that includes
the axis of rotation; third, that the various guideways 35 on the
rotary structure for guiding the plungers 34 accurately and
reliably maintain the plungers not only precisely parallel with the
axis of rotation of the rotary structure but also at correct rotary
positions on their longitudinal axes relative to the guideways for
precisely correct orientation of the corresponding follower rollers
36 and 38; and fourth, that the two follower rollers 36 and 38
closely hug the opposite faces of the cam track throughout each
revolution of each rotary structure. It is vitally essential that
backlash be eliminated to maintain these relationships.
The structural provisions for reliably and accurately maintaining
these relations will now be described. As shown in FIG. 7 the two
follower rollers 36 and 38 of each plunger 34 are carried by a
sturdy bracket 184 which has a shank 185 fitted snugly into an end
socket of the plunger with a slightly tapered fit and the shank is
securely anchored by a diametrical dowel 188. As indicated in FIG.
9, the two opposite ends of the dowel 118 are peened into
engagement with corresponding locking washers 100.
As shown in FIGS. 7, 8 and 11, the follower roller 36 is mounted on
the bracket 184 by means of an axle pin 192 that has a forced fit
in the bracket and is peened at its opposite ends into engagement
with corresponding lockwashers 194.
As best shown in FIG. 11, each of the follower rollers 38 is
mounted on a stud 195 that extends through a rotatably adjustable
flanged bushing 196, the exterior of the flanged bushing being
conical to fit tightly in a conically tapered bore 198 in the
bracket 184. The inner bore of the bushing 196 is eccentric
relative to the outer circumference of the bushing so that the
bushing may be rotated to shift the roller 38 snugly into contact
with the cam track 40. Thus the adjustable eccentric bushing 196
makes it possible to preload the two rollers 36 and 38 in
opposition to each other to eliminate any possibility of free play
between the rollers and the cam track.
Each of the plungers 34 is of noncircular cross-sectional
configuration and the corresponding guideway 35 is of complementary
noncircular configuration to prevent rotation of the plunger on its
axis and thus maintain the axis of the two follower rollers 36 and
38 in accurate radial alignment with the axis of rotation of the
rotary structure. In this particular embodiment of the invention,
each of the plungers 34 has a circumferential series of
longitudinal splines 200 which form corresponding longitudinal
grooves 202 (FIGS. 9 and 11) and the guideway 35 for each plunger
includes a pair of engagement means in the form of sleeves 203 and
204 that are formed with complementary splines that extend into the
longitudinal grooves 202. In the present embodiment of the
invention each of the sleeves 203 and 204 is in the form of a ball
nut which as indicated in FIG. 10 has a plurality of
circumferentially spaced radially inward splines in the form of
rows of balls 205 to engage the grooves 202.
As shown in FIGS. 7 and 14, the two ball nuts 204 are mounted in
corresponding cylindrically curved seats 206 in the guideway
casting 42 and the ball nuts are releasably secured by
corresponding end caps 208 and a pillow block 210, the end caps
being secured by suitable screws 212 and the pillow block being
releasably held by suitable screws 214. As shown in FIG. 7, the
sleeve 203 is anchored against rotation by a radial pin 215 that is
releasably retained by a metal clip 216 which in turn is held in
place by a screw 218. The rotary position of the ball nut 203 is
accurately determined to cause the balls 205 of the ball nut to
snugly abut corresponding splines 200 of the plunger 34 to oppose
rotation of the plunger on its axis in one rotary direction out of
its correct rotary position at which the axes of the two follower
rollers 36 and 38 are accurately radially aligned relative to the
axis of rotation of the rotary structure.
The second ball nut 204 is adjustable to permit it to be preloaded
against the ball nut 203 thereby to accurately maintain the
precisely correct rotary position of the plunger 34. For this
purpose, as best shown in FIGS. 12 and 13, a stud 220 is mounted
radially in the corresponding pillow block 210 and has a concentric
cylindrical enlargement 222 which backs against a shoulder 224. A
pair of nuts 225 on the outer end of the stud may be tightened to
releasably hold the stud against rotation. The stud 220 has a head
226 that extends from the enlargement 222 eccentrically thereof.
Thus the stud 220 may be rotatably adjusted to cause the head 222
to serve as a crank for rotating the ball nut 204 in a direction to
tighten the plunger 34 against the first ball nut 203. This
preloading of the two ball nuts in opposition to each other
eliminates any loose play between the plunger and the two ball
nuts.
As shown diagrammatically in FIG. 15, the rotary disk 75 of the
commutator means has three concentric rows of apertures, there
being 12 apertures in each row. The apertures 228 of the outer row
communicate with the 12 vacuum tubes 140 associated with the 12
seats of the main star wheel 62; the 12 apertures 230 of the
intermediate row are connected respectively to the previously
mentioned tubes 144 that supply compressed air to the 12 dies 48;
and the apertures 232 of the innermost row are connected to
corresponding tubes (not shown) for supplying lubricant to various
working parts including the 12 die assemblies 60.
As indicated in FIG. 16 the fixed disk 76 of the commutator means
has concentric grooves corresponding to the three concentric rows
of apertures in the rotary disk 75. The innermost concentric groove
240 is in communication with the previously mentioned oil pump 81
to snugly lubricant which is sprayed on the cam follower rollers; a
concentric arcuate groove 242 that cooperates with the intermediate
row of apertures 230 of the rotary disk 75 is in communication with
a suitable source of compressed air (not shown); a relatively long
outer arcuate groove 244 and a shorter outer arcuate groove 245
register with the outermost apertures 228 of the rotary disk 75 and
are in communication with the previously mentioned vacuum pump 80
in the hollow base 20.
FIG. 16 indicates diagrammatically how the fixed commutator disk 76
is divided into sectors in relation to a radial reference line 246.
Reading clockwise from the radial reference line 246, the first
sector of 60.degree. represents a dwell in the cam track 40 to
cause each of the plungers 34 to pause at its fully retracted
position to permit a new workpiece 92 to be placed in a peripheral
seat 146 of the input star wheel 145.
In the next sector which extends from 60.degree. to 117.degree., a
plunger 34 is advanced to cause the die 48 on the leading end
thereof to telescope into a workpiece on the input star wheel 145.
The next sector from 117.degree. to 183.degree. represents the
continued advance of each plunger 34 to move the corresponding
workpiece 92 from its position on the input star wheel 45 to a
peripheral seat on the main star wheel 62. The continued advance of
each plunger 34 represented by the sector 183.degree.-210.degree.
causes the die 48 on the plunger to cooperate with the
corresponding die assembly 60 to "dome" the workpiece, i.e.,
convert the bottom wall 95 of the workpiece to the configuration
indicated in FIG. 18. In the sector 210.degree.-237.degree., the
initial retraction of each plunger 34 occurs and at the same time
compressed air is supplied to the corresponding die 48 to urge the
finished workpiece against the die assembly 60 to strip the
workpiece from the die 48 and leave the workpiece free on its seat
on the main star wheel 62.
When an advancing plunger 34 carries a workpiece 92 from the input
star wheel 145 to a seat on the main star wheel 62, the newly
arrived workpiece is held in the seat mechanically by the arcuate
guardrail 155 as indicated in FIG. 15. While the workpiece is
within the range of the arcuate guard 155, the arcuate groove 244
of the fixed commutator disk 76 causes a vacuum to be created at
the corresponding seat of the main star wheel to keep the workpiece
on the star wheel after the workpiece clears the guardrail 155. As
may be seen in FIG. 16, this vacuum is maintained until the start
of the doming operation whereupon the vacuum terminates to give the
workpiece freedom during the doming operation. After the doming
operation when the plunger 34 initially retracts and when
compressed air is supplied by the arcuate groove 242 for stripping
the workpiece from the die 48, the short arcuate groove 245 creates
a vacuum to tend to hold the workpiece on its seat on the main star
wheel thereby to cooperate in the stripping of the workpiece from
the retracting plunger.
It may be readily understood that although the described apparatus
is relatively massive, the heavy rotary structure is rotated
continuously so that the whole mass of the rotary structure serves
as a flywheel in addition to the flywheel 77. Thus no problem
arises from the inertia of the heavy structure, the only inertia
forces being associated with the relatively lightweight plungers 34
and the dies thereon. With the rotary structure rotating, for
example, at 100 r.p.m. and with 12 workpieces processed on each
revolution of the rotary structure, the apparatus has a production
rate of 1,200 pieces per minute to justify its initial cost.
The fact that the apparatus is highly versatile may be understood
when it is considered that the dies 48 on the ends of the plungers
may be readily replaced by another set of dies and, in like manner,
the die assemblies 60 may be readily replaced. It is a simple
matter to replace any one of the plungers 34 by simply removing the
corresponding end caps 208 and the corresponding pillow block
210.
My description in specific detail of the presently preferred
embodiment of the invention will suggest various changes,
substitutions and other departures within the spirit and scope of
my invention.
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