Can end transfer mechanism

A can end transfer mechanism for use in a highspeed machine includes a generally horizontal base with an end-receiving pocket and a pair of can end-engaging members disposed on opposite sides of the pocket. Each of the members has an inner end portion which projects into the pocket and is dimensioned and configured to engage an opposite side of an end, so as to cooperatively constrain it against rotation in the pocket. The engaging members are resiliently mounted on the base for movement along axes which are inclined toward the vertical axis of the pocket; this facilitates insertion and removal of an end into and from the pocket, while effectively maintaining the relative lateral position of an end when received therein. The mechanism is particularly useful where proper registry of work sequentially performed on the end tends to be of critical importance.

BACKGROUND OF THE INVENTION 
Various types of mechanisms have in the past been employed to transfer can 
ends from one work station to another of a press, whereat various forming 
operations, such as scoring, rivet formation, etc., are sequentially 
performed on the ends. In the course of this progressive end-forming 
procedure, it is often imperative that the can end be transferred from one 
station to the next without a change in its angular orientation or lateral 
position. Otherwise, incorrect registry of the work performed on the end 
will result, ultimately leading to a defective can end. 
While satisfactory at moderate speeds, most presently-known can end 
transfer devices are found to be less satisfactory when operated at high 
speeds, particularly from the standpoint of affording adequately precise 
position control. This is due in part to the tendency of machine movement 
to be transmitted to the can end, with a consequential tendency for the 
position of the end in the transfer device to be changed. Moreover, in 
high-speed press operations, it is necessary that the mechanism be 
especially efficient in accepting and releasing ends quickly and facilely, 
and without damage to them. 
Accordingly, it is an object of this invention to provide a novel can end 
transfer mechanism for a machine, which mechanism is efficient, suited to 
high-speed operation, and capable of affording precise position control of 
ends transferred thereby. 
It is also an object of this invention to provide such a transfer mechanism 
by and from which can ends may be quickly and facilely accepted and 
released, without damage to the ends. 
A further object of this invention is to provide such a novel transfer 
mechanism which is simple, economical, durable and convenient to use. 
SUMMARY OF THE INVENTION 
It has now been found that certain of the foregoing and related objects of 
the invention are readily attained in a transfer mechanism for moving a 
can end between first and second, laterally spaced work stations of a 
high-speed machine, including a generally horizontal base having formed in 
its upper surface at least one downwardly extending end-receiving pocket. 
A pair of can end-engaging members are disposed on opposite sides of the 
pocket, and each member has an inner end portion which projects into the 
pocket and is dimensioned and configured to engage an opposite side of an 
end, so that the pair of members cooperatively constrain the end against 
rotation in the pocket. The mechanism additionally includes means for 
resiliently mounting the engaging members on the base for movement along 
axes which are inclined toward the vertical axis of the pocket; 
preferably, the inclined axes are at an angle of about forty-five degrees 
to the vertical axis of the pocket. As a result of the angular disposition 
and resilient mounting of the engaging members, ends may be facilely 
inserted into and removed from the pocket, and while their relative 
lateral positions therein may be effectively maintained. 
Preferably, the pocket is of circular cross section to adapt it for the 
receipt of a circular can end, with the inner end portions of each of the 
engaging members having a concave inner surface configuration. Most 
advantageously, the inner surface of each of the inner end portions is 
formed with a uniform radius which is shorter than the radius of the 
pocket (the latter corresponding to that of the can end for which it is 
designed), and is bevelled at its upper edge to facilitate entry of an end 
therebetween. In addition, it is highly desirable that the inner surface 
of the inner end portion of each engaging member terminate in a pair of 
circumferentially spaced, relatively sharp rectilinear edges, which are 
disposed parallel to the vertical axis of the pocket; such a construction 
will effectively prevent rotation of the can end in the pocket, without 
inhibiting its facile entry and exit thereinto and therefrom. In 
particularly preferred embodiments, the base includes a pair of 
spaced-apart, parallel rail members, which have opposed recesses formed in 
the confronting surfaces thereof, to cooperatively define the 
end-receiving pocket of the base. The rail members may also have a narrow 
ledge portion extending into the pocket, to provide underlying support for 
a can end seated thereon. 
Most advantageously, the resilient mounting means includes a support member 
for each of the engaging members which has an angled surface thereon, on 
which the engaging member is slidably seated. Preferably, the support 
member has a right angle channel formed therein, and has a first section 
thereof which slopes inwardly and upwardly toward the axis of the pocket, 
and a second section which slopes inwardly and downwardly theretoward, 
with the first section providing the angled surface of the support member. 
In such a construction, the engaging member is provided with a rectilinear 
intermediate portion, which is slidably engaged on the first section of 
the channel and which is slightly greater in length, and also with a foot 
portion at the outer end thereof projecting inwardly and downwardly at a 
right angle to the intermediate portion, toward the pocket axis. The foot 
portion serves as a stop to limit movement of the engaging member along 
the first channel section, by contact with the second section thereof. 
Finally, the resilient mounting means includes a spring, which biases the 
engaging member toward the pocket axis.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
Turning now in detail to the appended drawings, therein illustrated is a 
can end transfer mechanism embodying the present invention, employed in a 
high-speed inverted conversion press. The press includes a frame 10 (only 
portions of which are shown), having four upright cylindrical posts 12 to 
which a horizontal bolster plate 14 is rigidly secured. A vertically 
reciprocable, horizontal platen 16 is disposed beneath the bolster plate 
14, and has corner sleeve portions 18 in which the posts 12 are slidably 
received. 
A crankshaft 20, driven by suitable means (not shown), is rotatably mounted 
in the frame 10 beneath the platen 16, and has an eccentric 22 secured to 
it. The eccentric 22 is disposed within the guide collar portion 24 of a 
pitman 26, the upper end of which (not shown) is, in turn, pivotally 
connected (by means not shown) to the underside of the platen 16. As will 
be apparent, rotational movement of the shaft 20 is translated by the 
eccentric 22 and the pitman 26 into vertical reciprocation of the platen 
16. 
Four linearly aligned end-forming die sets (only one complete set being 
illustrated, for purposes of clarity), consisting of an upper member, 
generally designated by the numeral 32, and a lower member 34, are secured 
by means of die shoes 36 to the lower face 15 of plate 14 and the upper 
face 17 of the platen 16, respectively. Each set defines a work station at 
which a forming operation is performed on edge-curled, circular metal 
blanks 100, fed thereto. In operation, the end blanks 100, supported on 
the lower die members 34, are lifted by the lower platen 16; forming is 
effected by coaction of the lower members 34 with the mating upper members 
32 on the stationary bolster plate 14, which occurs at the top of the 
stroke of the platen 16. 
As can be seen best in FIG. 2, the upper die members 32 include a 
spring-loaded knock-out ring 38, and a similarly loaded, cylindrical 
knock-out collar 40, both of which are concentrically mounted about the 
forming die element 41. The outer ring 38 is slidably mounted on a pair of 
bolts 42, which are threadably engaged in the base portion 37 of the upper 
die member 32, and is fixed in proper position by a pair of nuts 39. The 
ring 38 is downwardly biased against the heads 44 of the bolts 42 by coil 
springs 46 mounted thereon. Similarly, the inner collar 40 is downwardly 
biased by coil springs 48, which act thereon through spring plungers 50 
(only one of the coil springs and plungers being shown), which are 
disposed within an upper housing portion 43 of the die member 32; as can 
be seen, downward travel of the collar 40 is limited by interference of 
its inner circumferential lip 45 with the element 41, which has a 
circumferential shoulder 47 formed therein to seat the lip 45. As can also 
be seen, the lower edge 49 of the collar 40 is tapered for close-fitting 
engagement in the circular groove 101 which is formed in each blank 100, 
thus best adapting the collar 40 to serve a centering, as well as a 
stripping, function. 
The blanks 100 are successively advanced from one station to the next by a 
transfer bar, generally designated by the numeral 52, comprised of a 
platform portion 54 at one end and a pair of spaced rail members 56 
extending therefrom. As will be noted, the underside of the platform 
portion 54 and the lower parts of the rail members 56 are configured for 
slidable engagement of the transfer bar 52 in upwardly-opening, U-shaped 
tracks 58, which are, in turn, supported on the inwardly-extending shelf 
portions 11 of the frame 10. 
A number of end-receiving pockets are defined in the rail members 56, by 
the provision of pairs of cooperating arcuate recesses 60, which are 
formed in confronting, opposed relationship therein. Within each recess 
60, a ledge 62 is provided, which is dimensioned and configured to seat 
thereon, and to provide underlying support for, one of the end blanks 100. 
The pockets are spaced and aligned to correspond with the spacing and 
alignment of the die sets comprising the end forming stations, so that, in 
lifting the end blanks 100 on the upstroke of the platen 16, the lower die 
members 34 pass upwardly through the pockets. The spacing between the rail 
members 56 is sufficient to permit the die members 34 to pass 
therethrough, thereby enabling reciprocation of the transfer bar 52 with 
the platen 16 in elevated positions, to achieve maximum operating speeds. 
Turning now particularly to FIGS. 3-7 of the drawings, therein provided is 
the most detailed illustration of the construction of the end-engaging 
mechanisms associated with the fourth and fifth pockets of the transfer 
bar 52 (as seen in FIGS. 1 and 2). Since all of the end-engaging 
mechanisms are of the same construction, a detailed description of only 
one of them is deemed sufficient. 
To accommodate the engaging mechanisms, each of the rail members 56 of the 
transfer bar 52 has formed in it, at an appropriate location adjacent the 
corresponding pocket, a cavity 64. A short alignment pin 66 projects 
inwardly into the cavity 64 from the inner wall 68 of the member 56 (which 
wall 68 is parallel to the axis of the pocket) and, in cooperation with a 
pair of fasteners 70, mounts a support block 72 thereon. The block 72 has 
formed along its rear surface a shallow, right angle channel consisting of 
upper and lower sections 74, 75, respectively; the channel is centrally 
disposed in the block 72, and each section 74, 75 thereof forms an angle 
of about 45.degree. with the front face 76 of the block 72, the latter 
being secured directly against the wall 68; thus, the channel sections are 
disposed at an angle of about 45.degree. to the pocket axis. 
Slidably seated within the channel 74 of the block 72 is an engagement 
finger, generally designated by the numeral 78. The finger 78 consists of 
a generally rectangular body 80 having a head portion 82 at one end and a 
foot portion 84 at the opposite end thereof. A substantially rectangular 
recess 86 is formed in the underside of the finger 78, and mates closely 
with the channel section 74 of the block 72; however, the recess 86 is 
slightly longer than the section 74, so as to permit a small degree of 
movement of the finger 78 therein. 
The finger 78 is confined within the right angle channel of the block 72 by 
an upper plate 88 and a backing plate 90, which are affixed to the block 
by suitable fasteners 77. A short coil spring 92, mounted between 
appropriate recesses provided respectively in the plate 90 and the finger 
78, serves to bias the finger 78 upwardly and inwardly toward the pocket 
of the rail member 56. Finally, a cover plate 94, having an appropriately 
configured opening 96 formed therein, is secured by suitable fasteners 79 
within the shallow recess 98 formed in the upper surface of the rail 
member 56 for that purpose. As will be evident, where the engaging 
mechanisms are employed, the end-receiving pockets are cooperatively 
defined by portions of the rail members 56, cover plates 94, and engaging 
mechanisms. Thus, as seen in FIGS. 2-6, the upper, inner edge of the rail 
member 56 is provided with a concave surface 55, which defines the lower 
vertical wall on one side of the pocket. The upper inner edge of the cover 
plate 94 is recessed to provide concave vertical wall sections 89 and 
horizontal annular surfaces 99, the former defining the uppermost vertical 
wall of the pocket, and the latter, together with the top surface 81 of 
the finger support member 72, defining the horizontal seating ledge of the 
pocket. 
The head portion 82 of each of the fingers 78 projects into its associated 
pocket, and has a concave inner surface, the upper portions 93 of which 
are bevelled to facilitate insertion of the can ends 100, by permitting 
them to cam the fingers 78 apart and by serving a centering function. In 
addition, the inner surface 91 is formed with a radius of curvature which 
is less than the radius of the pocket, so that four point contact (seen 
best in FIG. 5) may occur between the circumferentially-spaced, relatively 
sharp, rectilinear edges 85 of the fingers 78 and a can end 100 received 
therebetween. As will be appreciated, concentration of the holding force 
applied by the fingers 78 at four points maximizes their effectiveness in 
restraining rotation of the end 100 in the pocket; however, this is 
achieved without sacrifice of facility of insertion and removal, because 
of the alignment of the edges 85 with the vertical axis of the 
corresponding pocket. It should also be noted that the resiliency of the 
fingers 78, constrained to axes which are at an angle to the vertical axis 
of the pocket (due to the disposition of the channel section 74 of the 
block 72), enhances maintenance of the lateral position of an end blank 
100 held thereby. While the angle may be varied, 45.degree. has been found 
to provide an optimum balance between stability and positional accuracy of 
a supported end, and facile insertion and removal thereof into and from 
the pocket. 
As seen in FIG. 1, the transfer bar 52 has a cam follower support block 103 
projecting outwardly from the platform portion 54, on which block is 
carried a pair of depending cam followers 104. A cam wheel 105, having an 
upstanding undulating rib 106, is secured to shaft 109, with the rib 106 
disposed between the cam followers 104, causing them to ride on the 
opposite sides thereof. The shaft 109 is journaled in the frame 10, and 
carries a gear 107 which is in meshing engagement with the gear 108 
mounted on the crankshaft. Accordingly, rotation of the crankshaft 20 
turns the cam wheel 105, which movement is translated by the rib 106 and 
cam followers 104 into reciprocation of the transfer bar 52. Since the 
transfer bar 52 and the platen 16 are driven from a common prime mover, 
their operation will be synchronized. 
The end blanks 100 may be supplied to the transfer bar 52 from a stacking 
frame, shown fragmentarily in FIG. 1 and being generally designated 
therein by the numeral 110. The frame 110 is comprised of a base 111, 
which has a circular opening formed therein (obscured by the stack of end 
blanks 100), about which four upstanding posts 112 are positioned for 
lateral constraint of the vertical stack of blanks 100. The frame 110 is 
supported above the transfer bar 52 (by means not shown) so that, upon 
reciprocation of the transfer bar 52 therebelow, its vertical axis (and 
consequently that of the stack of ends 100) alternately aligns over the 
platform portion 54 of the bar 52 and the adjacent first pocket thereof 
(which, in FIG. 1, is aligned beneath the stacking axis). Although not 
fully illustrated, rigidly secured to the upper surface of the rail 
members 56, along the opposite sides of the first pocket, is a pair of 
blades 113, which project inwardly into the recesses 60. The blades 113 
are disposed to pass between the lowermost blank 100 in the stack and the 
one directly above it, engaging opposite sides of their curled, 
circumferential flanges 102. When the transfer bar 52 reaches its fully 
retracted position, the bottom blank 100 drops into the first pocket (then 
aligned under the stacking frame 100), with the blanks 100 thereabove 
being supported upon the blades 113. Upon extension of the bar 56, the 
blank 100 is advanced to the first station (an idle station) while the 
remaining blanks 100 drop onto the platform portion 54, and into position 
for entry of the blades 113 for feeding of the next blank 100. At this 
time, the lower platen 16 is on its upward stroke, and member 34 lifts the 
blank an amount sufficient to clear the first pocket and to bring it into 
clamping engagement with the upper member 32, whereat it is held while the 
transfer bar 52 returns to its retracted position to pick up the next 
blank. Thereafter, the platen 16 moves downwardly to lower the blank into 
the second pocket, for sequential transfer to the first forming station. 
The blanks are successively advanced, in similar fashion, to each of the 
other end forming stations. 
Following completion of the forming operation at the second forming 
station, the platen 16 moves downwardly to lower the blank 100 into the 
fourth pocket of the transfer bar 52, which includes the first pair of end 
engaging fingers 78. Initially, as seen more clearly in FIG. 6, after 
coaction of die members 32, 34, the pair of knock-out members 38, 40 
cooperate to strip the end blank 100 from the upper die 32, as the lower 
die 34 is retracted, and impart sufficient inertia (particularly ring 38) 
to the blank 100 to effect its insertion between the pair of fingers 78 
associated with the underlying pocket. 
Thus, as shown in FIG. 6, as the blank 100 is injected into the pocket, it 
initially contacts the bevelled edges 93 of the fingers 78, causing the 
fingers 78 to retract downwardly and outwardly from the axis of their 
associated pocket. Guided by the lead-in of the bevelled edges 93, the 
blank 100 moves downwardly along the vertical, parallel, rectilinear edges 
85 of the fingers 78 (FIG. 5), which ultimately clamp the blank 100 
therebetween in four-point contact; the blank 100 is, of course, also 
supported from below by the ledge-defining surfaces 81, 99. So restrained 
in the pocket, the blank 100 is advanced by the transfer bar 52 to the 
next work station, in proper registry for the forming operation to be 
effected thereat. Release of the can end is effected simply by applying 
upward force, such as with an appropriate die member. 
While the instant transfer mechanism has been described in relation to the 
illustrated and preferred embodiment, it should be understood that 
modifications may be made, as will be apparent to those skilled in the 
art. For example, while it is preferred that the mechanism employ a 
rectilinearly-reciprocable transfer bar, instead, it may be adapted for 
rotary movement. Additionally, it should be noted that the can ends may be 
fed to the transfer bar by other equivalent means. It should also be 
pointed out that, although the instant transfer mechanism is especially 
valuable in preventing rotation of circular can ends, a suitably 
configured mechanism may be employed for the transfer of non-circular can 
ends. Finally, it should be appreciated that, as shown in the drawings, 
the engaging mechanisms would not normally be employed at each pocket of 
the transfer bar, but are only required where maintenance of precise 
position of the can end during its transfer between two sequential 
operations tends to be critical. 
Thus, it can be seen that the present invention provides a novel can end 
transfer mechanism for a machine, which is efficient, suited for use at 
high speeds, and capable of affording precise position control of ends 
transferred thereby. Can ends may be rapidly facilely accepted and 
released by and from the mechanism, without damage to the ends, and the 
mechanism is simple, economical, durable and convenient to use.