Note: Descriptions are shown in the official language in which they were submitted.
Rotary Transfer Press
In the manufacture of components made from sheet
metal usually at least three or four distinct operations are re~
quired for completion. Typical examples are drawn and ironed cans
(D&I) and drawn and redrawn cans ~DrD).
-The manufacturing equipment has been evolving
over the years according to ~he demand, from simple solutions
comprising individual presses with single tools and manual trans-
fer of components, through designs whereby the transfer was mecha-
nized, to single stream transfer presses in which the progress of
components between tools is carried out by gripper mechanismsf
and to lar~e presses capable of accepting more than one stream of
components, the so-called multi-stream transfer presses.
In the case of high volume production the multi-
stream transfer presses, beingthe obvioussolu~ions,havebeen de-
veloped and successfully applied in practice, producing components
at an economic level. Low demands may be satisfied by single
stream transfer presses, but at a higher cost because the ratio
of capital investment per component produced is higher. This is
due to the complexity of the rnechanisms involved, revealing the
need or cheaper and yet equally reliable solutions.
In any type of pressworking machinery, when con--
sidering the events during the time of making of one component, i.e.
one cycle, useful work is performed during only a small fraction
of the cycle. Large flywheels are normally employed to provide the
required energy. During the working part of the cycle the flywheel
slows down, losing energy, and the lost energy is recovered durinq
the idle part of the cycle as the flywheel angular velocity is in-
i2~creased once more to its idling valueO By design, the transfer
presses not only require larger driving mechanisms, but also
must have the mechanical structure capable of withstanding the
sum of the process loads in each tool. Hence the structures of
transfer presses tend to be hea~y and expensiveO However transfer
presses have a small number of moving parts. In an attempt *o
decrease the size of ~he driving mechanisms, it has been proposed
to use a series of "C" type crank presses operating out of phase
with the crankshaftsin line,and coupled together and driven by
one power unit. This has the advantage of almost constant torque
throughout the cycle and hence requires a smaller power unit. How-
ever, each press, being independent, requires a suitable press
frame with an appropriate amount of metal for stiffness, which
performs a useful function for a small fraction of the cycle only.
Most transfer presses are of vertical type with
the punch moving down and up with the bottom dead center designated
for tool engagement. In such cases the component transfer mechanism
operates in the horizontal plane, the tool array being arranged
along a straight line, and the gripper pockets handlin~ the com-
ponents stop when reaching the tool position. Hence the transfer
mechanism must provide a suitably controlled motion of the gripper
pockets, usually along a D shape path, with acceptable acceleration
and deceleration. The mechanism must be stiff enough to ensure
precision of transfer. A stiffer mechanism is stronger and heavier
and generates higher inertia forces, and is also inevitably more
expensive to set up. In some low speed applications, where the
presses move horizontally, walking beam transfer mechanisms have
been used, whereby the transfer pockets are attached to a straight
beam which performs a parallel rotary motion. The component is
collected by the gripper pocket at finite velocity and is also
deposited in a suitable seat in the following tool at Einite velo-
city. In this case the transfer mechanism is extremely simple,
since rotary motion only is involved. The inevitable impact
between the component, transer pocket and tool nest is compen-
sated by attention ~o detail design and by operating at low speed.
According to a first aspect of the present invention
there is provided a method oE mechanically treating metal compo-
nents at a plurality of work s-tations arranged on a circular path
and each provided with a tool, comprising advancing the components
sequentially in stepwise Eashion, each from one station to at
least another station along said circular path, and applying force
to the components by means of the tools at the respective work
stations, said -tools being operated consecutively and each being
subjected only to a periodical reciprocating movement perpendic-
ular to the directions in which components enter and leave the
associated work station.
According to a second aspect of the present invention
there is provided a machine for mechanically treating components,
comprising a plurality of fixed work stations arranged in a cir-
cular path, transfer mechanism means for advancing each of the
components Erom one work station to at least another station along
said circular path, at least one tool at each work stations, each
tool having a working part which is constrained to move subs-tan~
tially perpendicularly to the plane of the directions in which
components are supplied to and collected from the work stations~
each tool including a ram member, a follower memher and means for
operating each tool while sa.id component is at i~s work station
and for operating all of said tools consecutively, the means for
operating each tool including a generally cylindrical cam member
having a central axis which passes through the center of said
circular path, said cam m~mber defining a cam track which is
engaged by said follower members, and means for driving the cam
member to rotate about said central axis and thereby act consec-
utively upon said follower members.
- 3a -
~8~%~
The present invention may be used to provide
a transfer press having a tool array arranged along a circular
path, the tools being actuated progressively by a single heavy
duty cam provided with a suitable "lift" along the working part~
The cam profile should ensure the lo~est possible contact stresses
between the cam followers a~tached to reciprocating rams, each
ram carrying a differen~ die. The cam profile includes also a
"dwell" portion, which maintains the followers and the rams with
dies in a stationar~ position during the part of the cycle when
transfer of components takes place. The cam is rotably mounted on
a cylindrical press stern around which ram carriers are equally
spaced. The press stern is in a form of a robust thick walled
tube, capable of resisting bendingwhenthe load is applied by the
cam and resisted by a circular bolster attached to the top of the
stern. While the press is in operation, the stern is loaded con-
tinuously as tools are being engaged successively. Likewise the
driving provisions do not require any flywheel, since at any one
time only one tool is in fully engaged position.
According to a third aspect of the present in-
vention there is provided a transfer mechanism, for transferring
components sequentially in stepwise fashion from one station to at
least one additional station, said stations each defining a center
and said centers being arranged on a first circle in equiangularly
spaced relation, the mechanism comprising a carrier member, a plurality
of pocket members carried by said carrier member, each pocket mem-
ber being adapted to receive a component for transporting it as the
carrier member rotates and defining a center, the centers of the
pocket members being on a second circle in equiangularly spaced re-
lation, and support means supporting the carrier member so that the
center of the second circle is spaced from the center of the
first circle and so that the carrier member is rotatable about
the center of the first circle without rotating about the cen-
ter of the second circle, whereby the center of each pocket
member moves in a circle passing through two adjacent stations. -
The invention may thus be used to provide atransfer mechanism capable of transferring the components succes-
sively one component at a time from tool to tool, and of collecting
a blank from outside of the press and feeding it into the first
tool, and ejecting the finished component from the last tool. The
transfer mechanism may perform a ~'pericycloidal" motion around the
tools, being based on a curved "walking beam" principle, taking
the shape of a complete ring embracing the tool array, having a
number of transfer pockets corresponding to the number of tools
in the press, or an integral multiple of that number, leaving at
least one idle positlon between the tools in which the component
waits for the duration of one cycle. The transfer ring provided
with suitable gripper pockets performs a rotary-parallel motion
in such a way, that the center of each pocket passes through the
axes of two tools, collecting the component from the first tool and
depositing it in the following tool, while moving along a circular
path. The transfer ring is driven by a crank, which is intergeared
with the driving cam, and is also supported by at least two further
"idler cranks" to guarantee the parallel-rotary motion. The length
of the driving crank, which is equal to the radius of the circular
path along which the transfer pockets move, depends on the timing
of the transfer; if for example half a cycle is allowed for transfer,
--5--
i.e. 180, the crank radius would be equal to half of the
distance between the tool axes, the di.stance between tools
being related to the transfer pa~h radius by the sine of half
of the feeding angle. The gripper pockets are provided.with
holding features, either magnetic or vacuum-based, to ensure
total control and reliability.
The transfer mechanism based on a "pericycloidal
motion" has speed limitations, due to.finite contact ~elocity
between the transfer pockets and the components, it is suitable
for low output requirements and'is inexpensive.
According to a fourth aspect of the present
invention there is provided a transfer mechanism, for transferring
components sequentially in stepwise fashion from one station to
at least one additional station, said stations each defining a
center and said centers being arranged on a first circle in equi-
angularly spa~ed relation, the mechanism comprising a first gear
having its pi~ch circle equal in diameter to said first circle
and having the center of said flrst circle on its central axis,
and a turret assembly comprising first, second and third turrets
each defining a plurality of pockets for receiving components,
each pocket defining a center and the centers of the pockets of'
the three turrets being on first, second and third turret circles
respectively, each turret also being provided with a ~ear having
its pitch circle equal in diameter to the respective turret circle
and having the centre of the turret circle on its central axis,
tlle gears of the first and second turrets being in meshing engage-
ment with the gear of the third turret, and the mechanism further
comprising support means whereby the turret assembly is supported
~2~
so that the gears of t}le first and second turrets are in
meshing engagement with said first gcar and the turret assembly
is rotatable about the center of said first circle, accompanied
by rotation o~ the turrets, the pockets of the first and second
turrets registering successivel~ with said stations and with
the pockets of the third turret, whereby a component can be
collected from said one station by caid first turret, transferred
to the second turret by way of said third turret, and deposited
in said additional station by said third turret.
The invention may thus be extended in accordance
with the fourth aspect to provide a transfer mechanism suitable
for high output requirements, capable of transferring components
successively, up to five components at a time from tool to tool
between operations, as well as collecting blanks from the outside
of the press and feeding them into the first tool or tools, and
ejecting the finished components from the last tool or tools.
Such a transfer mechanism performs an epicycloidal motion and
comprises a set of three turrets, two of which cooperate with the
tool array and the third connects them, being intergeared. The
set of these three turrets orbits around the tool array. There is
a stationary gear the pitch circle of which coincides with the pitch
circle of the tools. The two turrets which cooperate with the tool
array are driven by gears directly meshing with the stationary gear.
The turret driving gears' pitch circles are equal to the pitch circles
of the turrets. Consequently the component is placed in tools at
zero velocity, likewise it is collected from the tools at zero con-
tact velocity, and yet the set of the three turrets performs a con-
stant velocity epicycloidal motion, free of any intermittently-
--7
362'7
operating cams and linkage mechanisms. The epicyclo'idalhandling system of components may be employed for transfer
of components at four different stages of treatment,' and may
be used to serve one, two or three sets of ~ools in the same
press, thus satisfying high output req~lirements. The set of
the ~hree turrets can gyrate around the tool array at a speed
of up to 200 revolutions per minute, and would provide a corres-
ponding output depending whether one, two or three sets of
tools ha~e been provided in the press. This is most desirable
in production of two-piece cans. For adequate component control
during the transfer, the pockets in the turrets may be provided
with magnetic and vacuum features, mechanical means not however
being excluded. ~he three turret handling system allows a longer
part of the cycle for the operation of tools, hence the cam may
have a milder slope and higher lift.
The present invention may also be used to provide
a "package deal" system for economic low output two-piece can
bodymaking by D&I and by DrD processes, the system incorporating:
the'basic, vertical multi~ram, rotary cam, single action press,
and the circular beam transfer system with the number of pockets
related to the number of rams, performing rotary parallel motion
synchronized with the ram actuating cam, and suitable tools to carry
/ out required operations dictated ~y the given process, these tools
(Patent ~o. 3,924,437)
V~ being of KME design/or any other design suitable for single action
~b ~/ operation. The system may be fed with individual blanks or with
metal sheet material in strip and coil form, the material being
plain, lacquer coated or plastic film laminated tinplate, aluminum,
blackplate and nickelplated steeli or lacquer coated and plastic
~._
film laminated chromium plated steel known generallyas TFS .
The system is capahle of: feeding the ma~erial stock precisely
using the same dri~ing provisions as for the transfer mechanism,
cutting out suitable blanks, and ejecting thc residual skeleton
from the tool area ~fter chopping to manageable fragments.
The present invention may also be used to provide
a new configuration in press design, suitable for vertical types
and general application for manufacture of products re~uiring
multi-stage press operations, in which the.crank actuation has
been superceded by cams and cam derivatives, capable of successive
operation ~f rams wlth dies, through suitable followers.
The press stern may be central to correspond to
"C" frame design, or there may be four external pillars, similar
to those in "H" press frame. Similarly the transfer system may
be of external type embracing the tool array, as described; or
it may be within the tool array.
For a better understanding of the invention, and
to show how the same may be carried into ~ffect, reference will
now be made, by way of example, to the accompanying drawings in
which
Figure 1 shows diagrammatically a typical known
multi-die "H" frame press with a heavy flywheel;
Figure 2a shows diagrammatically a known "C" frame
press;
Figure 2b shows application of the "C" frame press
to multiple tools;
Figure 3 shows diagrammatically a known gripper
transfer performing "D" motion;
Figure 4 shows the principle of the known walking
beam transfer mechanism;
transfer mechanism;
~ 9 _
2~
Figure 5 shows diagrammatically., partly
in elevation and partly in section, a transfer press according
to the invention;
Figure 6a is an enlarged sectional view taken
on the line VIa-VIa of Figure S;
Figure 6b is a sectional view taken on the VIb-
VIb of Figure 6a;
. Figure 6c shows in simplîfied form successive
pOSitions of the components shown in Figure 6a;
Figure 7a shows diagrammatically a side elevation
of a second transfer press according to the invention;
Figure 7b is a sectional view taken on the line
VIIb-VIIb of Figure 7a;
Figures 8-1 to 8-6 shows plan views, at six
consecutive positions,ofa.first transfer mechanism according to
the invention;
Figures 9a and 9bshow the principle of inter-
action of certain components of the first transfer mechanism;
Figure 10 illustrates diagrammatically the re-
lationship between feed angle and cam lift angle;
Figure 11 shows a plan view of a modified- trans.fer
mechanism according to the invention;
Fi.gure 12 is a side elevation and Figure 13 is a
plan view of a mechanism for feeding strip ma~erial to the transfer
pressj
Figure 14 is a diagrammatic side elevation of a
mechanism for feeding coil material to the transfer press;
~ Figure 15 shows graphically the cam profile and
the second derivative of the cam profile;
--10--
Figure 16 shows the cam lift relative to the
tools at various cycle angles;
Figure 17 is a diagrammatic plan view of a second
transfer mechanism according ~o the invention;
Figure 18 is a side view, partly in elevation
and partly in section, of a press equipped with the second trans-
fer mechanism;
Figures l9a-19i show in simplified form nine
successive operating posi~ions of the second transfer system;
Figures 20a~20i show in simpliied form nine
successive positions over one half of the cycle of the second transfer
system operating with a press having two sets of four tools;
Figure 21 is a line diagram of component paths
between operations in a press according to the invention fitted
with two sets of four tools and the second transfer mechanism
Figure 22 is a line diagram showing relative
positions of components between operations in the system of Figure
21; and
Figure 23 shows the paths of components between
operations in the second transfer system when applied to a press
having three sets of four tools.
Referring to Figure 1 which shows a scheme of a
typical multi-die "H" frame press, there is a stiff vertical press
structure 101 supported on a press bed 102, and carrying press crown
103, all being clamped together by tie rods (not shown), so struc-
tures 101, 102, 103 are under compressive pre-load. Press crown 103
is equipped with bearings which support crankshaft 104 provided wi~h
two crankthrows 105 which actuate the crosshead 106 through connecting
36~7
rods 107 and gudgeo~ pins 108. The crosshead 106 is guided
precisely by linear bearings 109. The crankshaft 104 is rotated
by flywheel 110 which is driven by motor 111 through pulley 112
and vee-belts 113. Tools Tl, T2, T3 and T4 are attached to press
bed 102 and to the crosshead 106. By rotating the crankshaft 104
crosshead 106 moves down and up and tools close and open in syn-
chronism performing the allot~d tasks. Since the tools move in
synchronism, the tonnage which must be applied to the crosshead
is equal to the sum of individual loads o the tools. The energy
necessary is supplied by the flywheel 110, which slows when the
tools close and regains its speed when the tools separate. Such
presses may operate more tools, being loaded then proportionally
higher.
Figure 2a represents the "~" type press, of
which the frame structure 201 is characterized by width "W"
opposite the throat between ram 202 and bolster 206 which a,ccept
tools 205. The ram 202 is actuated by crankshaft 203 through
conrod 204. Ram 202 imposes a force "F" on tools 205 which in-
duces a reaction R in bolster 206. Depending on the press load
rating, normally expressed in "tonnes", width "W" of the press
frame is established to keep the bending stresses within safe
limits and to maintain the deflection at acceptable low values.
This means, that a volume of metal has to be contained in the frame
for satisfactory performance. For the manufacture of products
which require more operations, a separate press for each tool is
required. Figure 2b shows diagrammatically the case of four presses,
the crankshafts of which may be arranged at advantageous phase angles
so that only one crankshaft at a time is turning through the working
angle "~" (during which the punch penetrates the die).
~2~627
At position 207 with ram 202 at BDC work has been com-
pleted. At the same time ~he second press cran~. at position
208 is opening. The third press crank is fully open at position
209, with the ram at TDC, while ~he forth unit with the crank-
shaft at 210 position is closing. If the four crankshafts are
coupIed, then at any one ~ime only one tool is operati~g, re-
quiring only a medium size or small flywheel compared with that
shown in Figure 1.
Figure 3 illustrates a gripper transfer mechanism
in which the transfer pockets move along a "D" shape path. Such
an arrangement is most suitable for transfer presses similar to
that in Figure 1. Referring to Figure 3, blanks are stacked at
pOSltion 300. Single units are delivered to tool 301 where (as
shown in this case for clarity) it is drawn into a cup and promptly
moved into tool 302 for first redraw operation, then to tool 303
for second redraw and 304 for trimming operation to be then ejected
into position 305 ready to leave the machine. The transfer arra~ge-
ment operates in such a way, that the components at each stage of
production move simultaneously from tool to tool, being embraced
~y half-pockets attached to gripper bars 306 supported at points
307 and 308, which move along "D" shape paths 309 and 310. Gripper
bars 306 carry half pockets 311, 312, 313, 314 and 315.
Figure 4 shows the principle of the so-called
"Walking Beam" transfer mechanism. In this case cylindrical objects
400 roll down into a waiting position 401 which is in the form of
semicircular nest. There are four treatment positions defined ~y
semi-circular nests 402~ 403, 404 and 405 in which objects 400 rest
by means of gravity. There are five semi-circular transfer pockets
407, 408, 409, 410 and 911. The centers of these pockets move
along circular paths passing through centers of the nests 401, ~02,
403, 404 and 405. The transer pockets are attached to gripper
bar 412 which is suspended in points 413 and 414. The two points
413 and 414 are guided alQng circular paths 417 and 418 traced
by crankpins 415 and 416. Here the transfer pockets 407 to 411
meet the objects 400 at fini~e velocity and deposit them in successive
pockets also at finite velocity. During the travel from position
to position the force due to gravity holds the objects in the trans-
fer pockets. The last transfer pocke~ 411 deposits objects 400 at
the position 406, from which it is allowed ~o roll down. This
t,vpe of transfer system is simple as it employs rotary and constant
velocity motion. Because of finite contact velocity the speed
potential is limited. If applied in the horizontal plane, so that
gravity could not be used to hold ~he objects in the transfer poc-
kets, the objects may be held in the pockets by means of magnets
or suction, and if the transferred objects have a low mass, then the
operating speed could be increased.
Figure 5 s~hows schematically the press according
to the invention assuming a similar "tonnage" capacity to that of
the press illustrated in Figure 2. In this case the press stern 10
has diameter "D" whlch bears direct relationship with width W. Stern
10 is surrounded by a number of ram assemblies 11 carrying dies 12
cooperating with punches 13 attach~d to bolster 14 which is of circu-
lar shape. Bolster 14 is clamped to press stern 10 by several tie
bolts 15, which maintain the press stern in a state of pre-loading
compression. Tie bolts 15 are anchored to the base of stern 10 by
split-collars 16 embracing the bolts 15 at suitably provided
recesses and trapped in the fitting counterbores in stern 10.
Nuts 18 mounted on the tie bolts secure a clamping plate 17 to the
base of the stern lO.~ thrust bearing 19 is clamped between the
plate 17 and a flange 21' of a cylindrical cam 21, and a thrust
bearing 20 is clamped between the flange 21' and a shoulder 10'
of the s~ern. Bearings 19 and 20 are ~ocated inside the cylindri-
cal body of cam 21 which has a stroke "S" the value of which is
closely related to the application and to the type of tools to be
operatedO Cam 21 cooperates with the ram assemblies 11 through
follower rollers 22 and 23. Follower roller 22 has a substantial
diameter and width to suit the specified tonnage Follower 23 of
smaller diameter maintains contact between cam 21 and follower 22.
Both followers are mounted in a fork 24 attached to cylindrical
ram 25 which reciprocates in housing 26 provided with linear
bearings 27 and 28. Housing 26 is formed with slots 29 and 30
to guide fork 24 particularly when side thrust is induced when
follower 22 climbs cam 21. Housing 26 is rigldly clamped to press
stern 10 by bolts not shown. Ram assembly 11 represents therefore
a self contained unit actuated by cam 21. At three positions a-
round press stern 10 and between ram housings 26, three legs 31
are attached by bolts and dowels not shown. Legs 31 support the
press stern and the ram assemblies, and also the base casting 90
which retains lubricating oil and provides a guard for the cam
mechanism and the drive gear at the base of stern 10. Cam 21 is
driven by internal gear 32, which meshes with gear 33 mounted on
crankpin 34 attached at the end of long crankshaft 36. Four follower
rolls comprising pins 35 rigidlv mounted to retaining plate 17 and
provided with respective rotatable sleeves cooperate in four
2~7
circular holes in geax 33 to provide a necessary constraint for
gear 33 to drive internal gear 32. Crankshaft 36 is driven on
the top of the press by a highspeed motor not shown. The re-
quired reduction from say 1500 rpm to 60 rpm is obtained by this
set-up in one step.
Drive is also taken from gear 32 to which a
sprocket 37 is attached and provides motion through chain 38 to
sprocket 39 at one to one ratio: Sprocke~ 39 is mounted at the
end of long shaft 40, which carries at the top end a crank 41
driving a circular "walking beam", described with reference to
Figure 8. It can be seen that the press shown in Figure 5 is most
compact, the rams being built around the press stern.
Figure 6a shows a diagrammatic plan view and
Figure 6b a cross-section of the high reduction gear drive suit-
able for the transfer press according to the invention. Teeth
and pitch liners and center liners are shown. There are two gears
only, internal gear 32 attached to the rotating cam and gear 33
mounted on crank pin 34 attached to crankshaft 36. The speed re-
duction ratio i is given by the formula: i = t32/t32-t33
Hence if gear 32 has 100 teeth and gear 33 has 96 teeth,theA i =
25, which would reduce 1500 rpm to 60 rpm in one stage.
For clarity Figure 6a shows fewer teeth. Gear
33 has a central hole in which crank pin 34 turns; it also has four
holes 49 of diameter equal to the sum of the diameter of the crank-
pin 34 pitch and the diameter of the stationary pin 35. The pins
35 prevent rotation of gear 33 about~its own center, thus forcing
it to perform a parallel rotary motion about the center of gear 32.
In each revolution of gear 33 about the cen~er of gear 32, the latter
is shifted angularly b~ the difference of teeth between gea~s
32 and 33. Since the mass of gear 33 gyrates on a radius r,
equal to the distance between the centers of the gears 32 and 33,
it induces a centrifugal force, and balance weights 46 and 47
are provided to minimize the cyclic foxce on the crankshaft bearing
48.
Figure 6c illustrates the progressive positions
of the high reduction gear system. ~or clarity gear 32 is shown
with 26 teeth and gear 33 with 22 teeth. The starting position
of crankpin 34 is considered as 12 o'clock, the angle ~ between
the radius to the crank pin center anda line extending vertically
in Figure 6b is zero at that position. It should be noted that
at that position stationary pins 35 are at the bottom of circular
holes 49. Subsequent positions of crank pin 34 are equivalent
to 3/22, 9/22, 12/22, 18/22 and 21/22 of 360 rotation of the
crankshaft. It can be seen that gear 33 does not rotate, since
the axes passing through circular holes 49 remain vertical and
horizontal. Angle of rotation ~ of gear 32 has been indicated at
the progressive position showing clearly four teeth difference after
360, i.e. 4/26 x 360. ` ,
Figures 7a and 7b show a modification of the
~igure 5 press in which the central press stern is replaced by four
external pillars, thus providing a similarity with an "H" frame press.
An extended bolster plate 50 on top is connected to the base plate
51 by four pillars 52. Hence the press loads are not taken by the
tie bolts in the center stern, but by similar tie bolts placed in the
four pillaxs. The drive mechanism for the ram assemblies 11 is placed
in box 53.
~L21B~;Z~
Figure 8 illustrates the principle of the
circular walking beam transfer mechanism. For clarity, a six
station unit is shown, with five tool positions designated Tl
tQ T5and an idle position designatedO. In Figure 8-1 the driving
crank 41 is in 12 o'clock position indica~.ing zero cycle angle.
The mechanism comprises a transfer ring 43 provided with three
mounting pins 42. Two of the pins 42 are connected to idling
arms 44 which are mounted on bearing posts 45 attached to the
press legs 31 (Figure 5). The third pin 42 is connected to the
driving crank 41. Thus, as the shaft 40 rotates the ring 43
gyrates about the center of the press stern 10, ~he two idling
arms 44 always maintaining a parallel relationship to the driving
crank 41. There are six pockets, numbered ~ltoP6, attached to
transfer ring 43. Figure 8-1 shows the ring at a cycle angle
(the angle between the crank 41 and a line bisecting the angle
between the radii from the crankshaft 36 to the positions 0 and
5) of O with pocket 1 collecting a blank from the supply conveyor.
At the same time pocket 2 makes contact with the component in
tool l; pocket 3 is in a midway position between tool 2 and tool
3; pocket 4 has just delivered a component into tool 4; tool 5
is in closing positlon (the cam peak is approaching tool 5); poc- -
ket 5 has left tool 5 and is on the way to tool 4; and pocket 6
has just delivered a component into the exit chute.
Figure 8-2 shows the transfer mechanism at a cycle
angle of 60, the driving crank 41 having moved through 60 in counter-
clockwise direction and the peak of cam 21 m~rked CP having likewise moved through
60 in counterclockwise direction. Pocket 1 has reached the posi-
tion O; pocket 2 is in midway position between tools 1 and 2; pocket
-18-
3 has just delivered a ~omponent into tool 3; tools 4 and S are
being operated (tool 4 is c]osing while tool 5 is opening);
pockets 4 and 5 are on the return path to tools 3 and 4; and
pocket 6 is approaching tool 5.
It will be seen from Figures 8-3 to 8-6,
illustrating the mechanism at cycle angles of 120~, 180, 240
and 300, that the same pattern of movement takes place. At
a cycle angle of 300~ (Figure 8-6) one completed component is
delivered into the exit conveyor by pocket 6. The feed angle,
i.e. the angle through which the cra~k 41 moves in order to trans-
fer a component from one tool to the next f~llowing tool, is one
third of the total cycle angle and is thus equal to 120, and
to accommodate physically this feed angle, the cam dwell angle is
180.
Figure 9a shows the principle of interaction bet-
ween the transfer pockets of the ring 43 and locating rings at-
tached to the tools. Although it is known in the art to provide
"nests" for locating components in the tools, in the transfer
press according to the invention, additional features have been
included to ensure complete control of the components during
transfer and particularly at the instants of delivery and locating
in the tools. For clarity Figure 9a shows tools T2 and T3 dia-
grammatically as circles. These tools are beiny served by trans-
. the pocket P2 being
26 er pockets P2, P3 and P4,/shown in greater detail in Figure 9b.
Eacntool is embraced by a locating ring 701. At one side
each locating ring is provided with a locatin~ surface 702, which is
a segment of a cylindrical surface suitable ~o match the external
surface of the component. The locating surface is extended by three
--19--
36~
prongs 703, 704 and 705, which protrude upwards. Prong 703
is positioned centrally in relation to the locating sur~ace 702,
while prongs 704 and 705 are located on the ends of the lo-
cating surface. Prongs 703, 704 and 705 are of a suitabl~ width
and have gaps therebetween. The length of the prongs is at
least 3/4 of the height of the component to be transferred.
Transfer pocket. P2 is. . in the form of a plateof suit-
able thickness to ensure adequate sti~fness, and is . pro-
vided with a nesting surface 706, which fits the surface of the
component to be transferred, being in a form of a segment of cy-
linder extending through 120~. The nesting surface 706 is ex-
tended downwards by means of three prongs 707, 708 and 709.
Positioned centrally is prong 707, with prongs 708 and 709 at
the ends of the nesting surface and spaced from the prong 707.
The length of prongs 707, 708 and 709 is similar to that of the
prongs 703, 704 and 705. The gaps between prongs 707, 708 and
709 are wide enough to miss the die locating ring prongs 703,
704 and 705 while collecting the component from one tool and de-
positing it in the next tool.
The design of transfer pockets will vary depending
on the proportions of the component. The general rul.e is, that
the pocket must suit the conditions of the tool into which the
component is to be deposited, since it is extremely important when
the tool is closing on the component, that precise concentricity
is maintained. After the forming operation, the component's dia-
meter may be smaller and the cylindrical wall will not be contacting
the nesting surfacei it will however be concentric with the tool,
. urged by a spring 713
having been pushed out of the die by a pad 710/and kept in contact
-20-
with the pad 710 by a magnet or a vacuum device 711. In this
case the nesting surface of the transfer pocket will fit the com-
ponent, and the prongs of the transfer pocket will be suitably
located to miss the prongs of the locating ring. The transfer
pocket is provided with a magnetic device to retain the com-
ponent in the pocket.
The minimum cam dwell angle ~ is related
to the feed angle ~ and the number N of tools by the following
equation:
360
N
Figure 10 and the following Table clarify
the relationship between the cam dwell angle, the feed angle and
the number of tools. It has been assumed tha~ the effective feed
angle may vary between 90 and 180, although at 180 feed angle,
the dwell angle must be large, leaving little space for the cam
lift. The particular example on Figure 10 shows 120 feed angle,
which leaves 180 for the lift of the cam, identical to that in
the case of Figure 8.
Table
Effective
Feed angleNo. of ToolsCam dwell angle Cam lift angle
90 6 150C 210
12 120 240
120 6 180 180
12 150 210
150 6 210 150
12 180 180
180 6 240 120
12 210 150
The diameter dP of the transfer path is
given by:
sin ~2
where DT is the diameter o'f the tool pitch circle, N is the number
of stations and of transfer pockets and 5 is the feeding angle.
The diameter DP of the transfer pocket pitch
circle (and of the circle concentric with the tool pitch circle and
upon which the centers of the transfer paths are positioned) is given
by: -
DP = DT ~cos 180 + sin 180/N
N tan ~/2
Figure 11 illus~rates diagrammatically a twelvepocket transfer mechanism, which is the most likely and preferred
solution for the rotary transfer mechanism according to the invention.
It offers flexibility in application and minimum impact between the
workpiece and handling elements. Above a]l it allows a sizeable center
stern 10 of the press, the stern 10 being maintained in a state of
compression by at least six tie bolts 15, which contribute to stiff-
ness of the structure. Center stern 10 is embraced by transfer ring
43 supported on pivots 42. It carries twelve pockets, each of suitable
siæe to fit the exact dimensions of the component after being operated
upon by the tool from which it is collected by the pocket.
There are a number of possibilities with this
set-up. For higher outputs one could employ two sets of tools. In
such a case the material blanks would be delivered into first and
seventh station, and components would be extracted from fifth and
eleventh tool, lea~ing stations 6 and 12 idle.
Alernatively, by employing six tools only, an
idle station could be provided between each pair of successive tools,
offering the possibility of inspection after each operation~ This may
-22-
:~2,~
be achieved by providing at each idle station a component
handlingnest whichis removable, and an exit chute comprising
two guides (as shown in Figures 8-6). The transfer pocket feeding
a particular idle station deposits a partly manufactured component
in the removable component handling nest and the nest is removed
from the idle station by way of the exit chute. The component
can then be inspected and the nest containing the component re-
placed at the idle station. The nest must be replaced within one
period of the cycle of operation of the press, since otherwise
the nes~ would not be availa~le to receive the next component
and the next component would accordingly be returned to the pre-
ceding station and crashed between the prongs of the nest at that
station. Inspection would take place at regular intervals. Thus,
it would be possible to inspect not only finished components but
also partly manufactured components, and this is important when it
is desired to meet particularly high quality standards. Further
possibilities are contemplated. For example, the material might .
be supplied in short strip form or in continuous coil form, in
which case the first pocket of the rotary transfer collects a cup
or blank from a cupping/blanking tool~ which does not require a
component locating nest and which would be placed in the idle station
O of Figure 8, or at each of the idle stations 6 and 12 of the
Figure ].1 arrangement employing two sets of tools. As finished
components are ejected from the last tool, they would have to pass
over the punch of the cupping tool. This is possible precisely be-
cause the latter tool is not provided with a nest.
The number of transfer pockets is primarily
dictated by the capacity of the press, which requires suitable di-
mensions for the center stern 10. In particular, when the press is
to be used for two~piece can making, or when an ironing operation is
i:
-23-
included the ram capacity at the early operations could be up to
12 tonnes. At one time for short periods, one has to assume for
safety in design, that up to 3 tools could be developing the
working loads, and the center stern must therefore be of sufficient
diametex and provided with a suitable number of tie bolts 15, to
resist safely 36 tonnes. Another important parameter, which in- --
fluences the size of the press is ~he pitch between the tools, de-
pending mainly on the size of the tools dictated by the component
made.
. Figures 12 and 13 show diagrammatically the
application of the strip-feeding to the press according to the in~ention.
The purpose is to feed strip 50' ~o the cupping tool 51' located at the
idle station O of Figure 8. This is achieved in a manner well known
in the art by feed bar 52' and auxiliary feed b~ 53', to which the
strip 50' is supplied from the stack of strips (not shown~ by mechanisms
(not shown). Feed bars 52' and 53' are reciprocated by connectlng rods
54 and 55 driven by a double eccentric 56, attached to crank 57 at the
end of drive shaft 58. The double eccentric 56 is adjustable along
crank 57 to ensure that ~he feed bars can be actuated at different
strokes. It will be seen, that the auxiliary feed bar has a longer
stroke Crankshaft 58 has a driving sprocket 59 which is wrapped by
chain 38 (Figure 13) taking the movement from driving sprocket 37,
which also drives sprockets 39 and crankshaft 40 ~Figure 5).
Handling of the strip is effected by means of
pneumatic devices (not shown), but the steering mechanism for controlling
operation of the pneumatic devices has been illustrated on Figures
-24-
12 and 13. The steering mechanism may take drive from any
cyclic shaft for example shaft 40 to which driving sprocket 60
is attached actuating chain 61 wrapped also around sprocket
62. The ratio of teeth in sprockets 62 and 61 represents the
number n of blanks in strip S0. Thus, while each revolution
of the sprocket 59, and hence of the sprocket 60, is associated
with advancing the strip by one blank, n revolutions of the
sprockets 59 and 60 are required in order to rotate the sprocket
62 through one revolution. Sprocket 62 drives steering shaft 63,
to which a number of steering cams axe keyed, each cam operating
suitable pneumatic valves. The pneumatic valves provide instruc-
tions for pneumatic cylinders (not shown) which operate the strip
handling mechanisms, before the strip reaches the auxiliary feed
bar position.
Hence cam 64 operates valve 65 controlling the
movement of the vacuum sucker mechanism. Cam 66 operates valve
67 controlling the movement of the translator mechanism~ which .
shifts the strip 50 sideways into the path of auxiliary feed bar
53.1 Cam 68 operates valve 69 controlling the scrap ejecting rolls.
Cam 70 operates valve 71, which controls the vacuum admission into
the suckers. The arrangement shown in Figures 12 and 13 and des-
cribed above is one of many which could be employed as a strip
feeder to the press according to the invention.
Figure 14 shows diagrammatically a coil feed
mechanism. Narrow strip 80 is mounted on expanding mandrel 81~
Pinch rolls 82 pull strip 80 and thus rotate the mandrel 81. The
rotation of pinch rolls 82 is controlled by "dancer" roll 83, which
is provided with a switch (not shown) to switch "on" and "off" the
-24a-
~2~62~
motor (not shown) driving pinch rolls 82~ Another se-t of pinch
rolls 84 driven intermittently from the press through a suitable
stop and move mechani'sm such as a Maltese cross mechanism (not
shown) feeds strip ~0 into the cupping tool 85 which is ldentical
to cupping tool 51~in Figure 13. Strip 80 is guided by stripper ,
plate 86. As shown in Figure 1~, when the punch 87 is in its lower
dwell position, i~ leaves space between its top face and the
stripper plate 86, for the rotary transfer poc~et ejecting the
finished component from the press through the idle station 0, as ex-
plained previousl~.
~igure 15 shows diagrammaticall~ the profile
'~' of the actuating cam 21. ~s discussed previously and illustrated
in Flgure 10, the value of the cam lift angle depends on the transfer
feed angle and the number of stations. The most likely and pre-
ferred value of t~e cam lift angle will be between 180 and 240.
The lift of'the cam depends on the height of the container and the
-type of the tools employed. It may be equal to three times the
finished before trimming.
height of the/container/ The cam shape or profile has a constraint
~l in the form of the maximumincline angle at the nodal point-N, where
normally acceleration changes to deceleration: at that point dy/d~
must not be greater than tangent 30~ for smooth operation. This
constraint dictates also the size condition for the cam 21, the dia-
meter of which may have to be increased in order to decrease the
slope of the cam at the nodal point N. In addition the cam lift
angle must also be kept to maximum possible value. If the accelera-
tion curve is similar' to that shown in Figure 15, the slope of the
cam at point N will be kept to minimum.
The design and features of cam ~1 are an imp~rtant
point of the press according to the invention. It allows the ar-
rangement of the tool array along a circular path, and successive
actuation of the tools. It ~eaves a suitable fraction of the
cycle time available for feeding by tlle rotary transfer arrange-
ment, which performs at constant ~elocity and does not require
intricate intermittently operated mechanisms.
In order to explain clearly the relationship
between the cam and tool positions as progressively shown in Figure
~, reference will now be made to Fi~ure 16, from which it can be
seen that at zero cycle angle the cam peak CP is between idle posi-
tion zero and tool position 5. At 60 cycle angle CP is between tool
pOSitions 4 and 5, and at subsequent cycle angles 120, 180, 24t',
and 300, CP is between positions 3 and 4, 2 and 3, 1 and 2, 0 and 1
respectively. Only a certain part of the cam rise near CP performs
the "working" lift, the remainder serving an assembly function, i.e.
closing the tool, component and die together without deforming the
component. Figure 16 illustrates clearly, that with the tools spaced
apart angularly by 60 (i.e. with five tool positions and one idle
position), one tool at a time will perform useful work. This is de-
sirable for two principal reasons. First, it is essential that the
component be centered accurately on the die, so that the punch may
enter it. In the case of Figure 1, there is at any one time more
than one tool developing a workin~; load, and this results in deflection
of the structure 101 which may interfere with precise entry of the punch
into the component. Figure 16 shows that during assembly of the
component onto the punch, the press is not loaded and accordingly the
relationship between the punch and die is not affected by other tools.
Second, if more than one tool performs useful work at a time, as in the
case of Figure 1, there may be an interaction between the tools resulting
from the deflection which has to be compensated for, e.g. by setting
some tools eccentrically to compensate for lateral deflection. In
~ddition, power requirements are minimized. The number of tools could
-26-
be increased and the working lift of the cam rise would still
operate on only one tool at a time, which is beneicial for the
reasons explained, and also with regard to the pr~ss frame load
magnitude. The dwell and lift angles shown in Figure 16 are equal
and reference may be made to Figure 10 for further details.
. For high speed applications, or example
manufacture of two-piece cans by DrD method, an epicycloidal handling
system, as illustrated in Figures 17 and 18, is suitable. In this
case there are four tools Tl, T2, T3, T4 positioned along a circle
which coincides with the pitch circle of a stationary gear 501 which
is mounted on the bolster 14 (Figure 18) by means of tie bolts 535.
,,
,
.
,/
~__ ._ _._ _ __ .... .. _ ...... _ _.
-26a-
~.2~
A carrier ring CR is mounted by means of a bearing 536 to
rotate about the axis of the crankshaft 36. A reduction gear
comprising elements 532, 5~3, 534 and 535 ~corresponding to the
elements 32, 33, 34 and 35 o~ Figure 6b) transmits drive from
the motor M to the carrier-ring CR, and thus causes the ring C~ .
to rotate about the center stern 10 at the same speed as the cam
21.
The carrier ring CR carries three turret housings
H, of which only two can be seen in Figure 18. Each turret housing
H is hollow and has a shaft 539 extending axlally therethrough,
mounted in bearings 537,538. Three turrets 505, 506 and 507 are
mounted on the lower ends of t~e shafts respectively, and three
gears 502, 503 and 504 are keyed to the shafts respectively at their
upper ends. The gears 502 and 503 mesh with the gear 501 while
the gear 504 meshes with the gears-502 and 503, as shown in Figure
17. The angular relationship ~ between gear centers 502 and 504,
also 503 and 504 is 25.87. While gear 501 is stationary, the th~ree
gear set 502, 503 and 504 and the three turrets 505, 506 and 507
gyrate counterclockwise and the turrets themselves rotate about
their own axes, driven by the respective gears. The mass of the
turrets is balanced by a balance member BL on the opposite side of
the carrier ring CR from the turrets.
Each turret has four pockets 1, 2, 3 and 4, which
match exactly the diameters of components at the four stages of
manufacture. The turrets are arranged so that a given pocket of
the entry turret 506 deposits a component into the tool of corres-
ponding diameter. Thus, a component enters the tool Tl from the
pocket 1 of turret 506 with diameter 1 and after reduction ~o dia-
meter 2 it is collected by pocket 2 of extract turret 505 and trans-
ferred via pocket 2 in trans---__________________
-~7-
2~7
fer turret 507 to pocket 2 of entry turret 506, which deposits
it into tool T2. After reduction to diameter 3 in ~ool T2, the
component is collected from tool T2 by pocket 3 of extract tur-
ret 505 and deposited by pocket 3 of entry turret 506 in tool T3.
After reduction to diameter 4 in tool T3, the component is col-
lected from tool T3 by pocket 4 of extract turret 505 and deposited
by pocket 4 of entry turret in tool T4. Finally, after trimming,
without diameter reduction, in tool T4, the component is collected
b~ pocket 1 of extract turret 505 (which pocket is the same size as
pocket 4 of turret 505) and is discharged from pocket 1 of transfer
turret 507.
One blank at a time is separated.from stack of
blanks 508 and transported along a circular blank transfer path 509
by rotary pocket 510 provided with a suitable nest to fit diameter
1 and also another nest underneath to fit diameter 4. Rotary
pocket 510 deposits blank 1 in transfer turret 507 at point 511,
and also extracts a component of diameter 4 from transfer turret
507 and places it on the exit conveyor 512. From point 511 the
blank 1 travels to tool Tl along path 513. From tool Tl to T2 the
components of diameter 2 travels along path 514. From T2 to T3
the component of diameter 3 moves along path 515. From T3 to T~
the component of diameter 4 moves along path 516. Erom T4 to point
511 the comporen~oEdiam2ter 4 travels along the first half of path
513. It should be noted, that the components are handled bet~een
the pitch circle of gear 501 and limit circle 517 by extract turret
505 and by entry turret S06. Outsi.de limit circle 517 components
are handled by transfer turret 507. In this particular arrangement
the ratio of the pitch diameter of gear 501 to the pitch diameter
-28-
of gears 502, 5b3 and 504 is 3:1.
Figure 19 illustr~tes the progressive positions
of the epicycloidal handling systems and components in relaition to
tools at characteristic intervals. Figure l9a shows the starting
position with blank 1 collected by transfer turret 507 and component
of diameter 4 ejected from turret 507. In Figure l9b, pocket 2 of
extract turret 505 makes contact with component of diameter 2 in tool
Tl. Between Figures l9b and l9c blank 1 is transfexred into entry
turret 506 approaching tool Tl, while component of diameter 2 is moving
away from tool Tl in extract turret 505. In Figure l9c blank 1 is
placed in Tl, whereas component of diameter 2 is moved into transfer
turret 507. Between Figures l9c and l9d it would be noted that the
center line of transfer turret 507 has moved through 90 and component
of diameter 2 has assumed the extreme positîon in turret 507, corres-
ponding to the position of blank 1 in Figure 19a. It follows that at
in Figures l9d and l9e extraction of component of diameter 3 from T2
by extract turret 505 takes place followed by deposition of a fresh
component of diameter 2 in tool T2 by turret 506. Between Figures l9e
and l9f extract turret has moved through 180 and has component of
diameter 3 in the extreme position. In Figures l9f and l9g the process
of extracting component of diameter 4 from tool T3 and depositing a
fresh component of diameter 3 in tool T3 takes place. Between Figures
lS~ and 19~h the extract turret 507 has moved through 270~ and component
of diameter 4 is in the extreme position. Figures 19h to 19i illustrate
unloading of tool T4 by pocket 1 of extract turret 505 removing com-
ponent of diameter 4, followed by loading of a fresh component of dia-
meter 4 from the pocket 4 of entry turret 506. It will be appreciated`
that the turrets 505 and 506 handle the components into and out of the
tools without any impact. ~ence, the epicycloidal handling system is
suitable for high speed use. It will also be appreciated that once
`:
~29-
a pocket in any of the three turrets has been designated to handle
the component during a certain phase of manufacture, it always does
so =
Figur~ 20 illustxates progressive positions
of a single epicycloldal handling system for two sets of four tools.
There is a similarity to the case illustrated in Figure 19, in as much
as there are three intergeare~ handling turrets, but the relative
angle ~ between them is 35. Also the ratio of pitch diam~ters of ~ools
to turrets is 2:1. The extra~t turret 505 and the entry turret 506
handle the components between pitch circle of gear 501 and limit circle
517, while the transfer turret 507 handles components outside the limit
circle 517. By examining ~he nine positions shown at ~igures
20a to 20i over half a cycle, it can be seen that these positions are
repeated in the second half of the cycle~ At position 20a blanks
are placed into the system and finished components are extracted as
shown clearly in Figure 21. Hence there are two blank supplies and
two finished components extracts, which follows of course from there
being two sets of tools available. Hence for one revolution of the
press and handling system, two components are completed. It should be
noted that both in Figure 19 and in Figure 20 the cam dwell is equal
to 2~, hence 52 and 70 respectively.
Figure 21 illustrates the paths of components
between operations for the epicycloidal handling system with two sets
of tools and two blank feeding arrangements. It is evident that the
blank after entering the handling system travels over 1.5 revolutions,
hence the finished component leaves through the opposite entry/exit
station from that at which the original blank entered.
Figure 22 illustrates the relative positions of
components between operations for two sets of four tools. It can be
.
--30-
seen that at the i~s~an~ when an entry turret deposi~s a
component into a tool, there are five components in the handling
system.
~ igure 23 shows how a single epicycloidal
handling system may be applied to three sets of follr tools. With
three in-feeds of blanks~ it is in effect a tripling of the system
shown in Figure 17. Since the preferred solution of the rotary
cam pxess according to the invention would incorporate 12 working
rams, use of three in-feeds is particularly advantageous.
The tool of each of said work stations may
either be a conventional drawing or ironing ~ool, a combination of
both, or a multiple tool comprising several coaxially arranged
ironing rings. It is to be understood that any other known type of
tool suitable for metal working, such as stamping, trimming,
flanging, beading etc. may also be used within the protecting scope
of the present invention.
~1
~ .
