Hollow forming blocks for double package forming machines

An improved forming block (10) is described for forming double packages including a liner enclosed within a carton. The forming block (10) includes a mandrel (12) having a free, open end (30) partially closed by an end piece (14). The mandrel (12) includes a hollow core (16) having a periphery around which the double package is formed. The mandrel (12) further includes a mounting bracket (18) which mounts the mandrel (12) in a cantilever manner to the forming machine and includes a hollow interconnecting portion (20). Ambient air is in communication to the interior of the core (16) by apertures (56) formed in the interconnecting portion (20). Air communication is also provided from the interior of the core (16) and the interior of the double package through apertures (76) formed in the end piece (14) and through vent holes (40) formed in the core (16) adjacent the open end (30). Longitudinal grooves (34) are formed in each of the sides (22, 24) of the periphery of the core (16) and corresponding to the hooks (36) of the stripper bars (38) for providing air communication between the liner of the double package and the mandrel (12) to provide communication of ambient air therealong and to allow movement of the stripper bars (38) without engaging the mandrel (12). In the preferred form, the vent holes (40) are located within and in air communication with the longitudinal grooves (34).

BACKGROUND 
The present invention generally relates to machines for forming double 
packages, and particularly to forming blocks utilized in double package 
forming machines, and more particularly to forming blocks allowing ease of 
stripping of double packages from the forming machines, with the double 
packages being intact and of a consistent quality. 
A common method of packaging cereals and other foodstuffs is a double 
package comprising a liner enclosed within a carton. In the past, such 
liners were formed of glassine or wax paper, however, the use of plastic 
liners has been increasing because of the advantages obtained thereover. 
Specifically, plastic liners provide a better moisture seal to the food 
stuffs being packaged providing extended freshness without staleness. 
Additionally, plastic liners have a greater tendency to prevent tearing or 
ripping. A further benefit obtained is that the liner is more consumer 
friendly allowing the liner to be opened without tearing or ripping and 
allowing the liner to be resealed by the consumer to preserve freshness. 
Further, the cost of plastic liners tends to be relatively less than the 
cost of prior glassine or wax paper liners. 
However, one difference between plastic and prior glassine liners is that 
plastic is structurally more flimsy and has a greater tendency to 
collapse. Collapse of the liner may disrupt the proper functioning of the 
remaining packaging operations including but not limited to the filling of 
food stuffs into the liner, the dropping of coupons or premiums inside of 
the liner, closing and sealing the liner, and like operations. One major 
cause of liner collapse is problems in removing the double package from 
the forming block. 
A typical method of forming a double package is to rotate a forming block 
through a series of steps where the liner and carton are formed on and 
then removed from the forming block. An example of a double package 
forming machine and its method of operation is set forth in U.S. Pat. No. 
2,364,406 issued on Dec. 5, 1944 to J. G. Vergobbi. Specifically, the 
liner material is cut and wrapped around the forming block and the upper 
edges are sealed together, which in the case of plastic liners are fin 
sealed by sealing the two edges of the liner material in a face to face 
manner. Next, the bottom of the liner is sealed together, which in the 
case of plastic liners again is fin sealed. 
After the side and bottom of the liner are sealed, a pattern of adhesive is 
applied to a flat blank for forming the carton. In the case of plastic 
liners where heat is not required to seal the liner, hot melt adhesive may 
be utilized. The blank is wrapped around the liner located on the forming 
block and the side flap is clamped down on the side of the blank. Next, 
the bottom flaps are tucked in and the bottom of the blank is clamped 
against the liner located on the forming block. Pressure may be applied to 
crease the bottom corners of the carton to form a more stackable, stable 
carton, to spread and adhere the adhesive, and in the case of cold 
adhesive to cure the adhesive. It can be appreciated that adhesive may be 
applied to the blank to not only form the carton but also to attach the 
liner to the carton. The formed carton and liner is then stripped from the 
forming block by reciprocating a stripper bar relative to the forming 
block along a longitudinal path from beyond the free end of the forming 
block to beyond the top edges of the carton, and then moving the stripper 
bar back to hook the free edges of the top flaps and pull the carton and 
liner from the forming block for transport to other packaging operations 
when the stripper bar is moved back to beyond the free end of the forming 
block. 
In pulling the carton and liner from the forming block, a piston effect is 
created by the forming block as the carton and liner formed therein are 
withdrawn from the forming block. This piston effect creates a vacuum 
inside of the liner between the liner and the forming block. The vacuum 
force has a tendency to collapse the liner especially when the liner was 
formed of plastic which is more flimsy than glassine or other liner 
material. Prior to the present invention, compressed air was forced 
through tubes extending to the bottom of the forming block to fill the 
void created in the liner as the forming block moved out of the liner and 
the carton to assist the removal of the liner and carton from the forming 
block. It can be appreciated that the introduction of compressed air had 
to be exactly timed with the movement of the stripper bars. Such timing is 
difficult to obtain especially at the speed of operation of such double 
package forming machines where between 50 to 60 double packages are formed 
per minute. 
Accordingly, in the development of machines for forming double packages and 
especially double packages including plastic liners, it is imperative that 
the forming blocks prevent the collapse of the liner as well as deliver 
consistent, quality double packages. 
Thus, it is an object of the present invention to provide a novel forming 
block for double package forming machines, with the double package 
including a plastic liner in the preferred form. 
Another object of the invention is to provide a novel forming block 
including provisions for providing communication of ambient air to the 
interior of the liner of the double package to offset the vacuum 
potentially created when the double package is stripped from the forming 
block. 
Yet another object of the invention is to provide a novel hollow forming 
block allowing ambient air flow to the interior of the hollow forming 
block to adjacent the free end of the forming block and at a rate to 
prevent the creation of a vacuum when the double package is stripped from 
the forming block. 
Still further, another object of the invention is to provide grooves on the 
periphery of the forming block for providing communication of ambient air 
between the liner of the double package and the periphery of the forming 
block. 
In another aspect of the present invention, a further object is to provide 
the periphery grooves corresponding to the longitudinal path of the hooks 
of the stripper bars to allow movement of the stripper bars without 
engaging the forming block. 
SUMMARY 
Surprisingly, the above objectives can be satisfied in the field of double 
package forming machines by providing in the preferred form, an improved 
forming block including a hollow core upon which the double package is 
formed, with communication of ambient air being provided to the interior 
of the core, through the core, and to the interior of the liner of the 
double package adjacent the free end of the core, with the air flow 
allowed being sufficient to prevent the creation of a vacuum within the 
double package while the double package is being stripped from the forming 
block. 
In other aspects of the present invention, an improved forming block is 
provided including a longitudinal groove of a width at least equal to the 
width of the hook of the stripper bar and located on the forming block in 
the longitudinal path of the hook of the stripper bar to provide air 
communication between the liner of the double package and the forming 
block to offset the vacuum created when the double package is stripped 
from the forming block and allowing movement of the stripper bar without 
engaging the forming block. 
The present invention will become clearer in light of the following 
detailed description of an illustrative embodiment of this invention 
described in connection with the drawings.

DESCRIPTION 
A forming block utilized in a double package forming machine for forming 
double packages for cereal, other food stuffs, or the like according to 
the preferred teachings of the present invention is shown in the drawings 
and generally designated 10. In the most preferred form, forming block 10 
is formed by a generally hollow mandrel 12 having an attached end piece 
14. 
Mandrel 12 generally includes a core 16 upon which the carton and liner are 
shaped and formed, a mounting bracket 18 for attaching mandrel 12 to the 
double package forming machine, not shown, and an intermediate, 
interconnecting portion 20. Core 16 comprises a hollow parallelepiped 
including an outer periphery of a size and shape corresponding to the 
double package desired to be formed. The outer periphery of core 16 is 
defined in the most preferred form by two parallel sides 22 and 24 and by 
a top 26 and a bottom 28 arranged parallel to each other and joining sides 
22 and 24, with top 26 and bottom 28 extending generally perpendicular to 
and between sides 22 and 24. Sides 22 and 24, top 26, and bottom 28 are 
solid in construction. The hollow interior of core 16 has a cross 
sectional area of a size substantial to the cross section of the double 
package desired to be formed, or in other words, the cross section of the 
outer periphery of core 16, and particularly the hollow interior of core 
16 has a cross sectional area equal to the cross sectional area of the 
outer periphery of core 16 less the cross sectional area of sides 22 and 
24, top 26, and bottom 28. The free edges of sides 22 and 24, top 26, and 
bottom 28 form an open end 30. In the most preferred form, sides 22 and 
24, top 26, and bottom 28 have a slight taper inwardly towards end 30 and 
the outside corners at the interconnection of sides 22 and 24 with top 26 
and bottom 28 are chamfered for ease of removal of the formed liner and 
carton from forming block 10. Top 26 includes a flap groove 32 extending 
from the interconnection of top 26 and side 24 of a size for receipt of 
the side flap attached to the back of the carton and which is secured to 
the side of the carton to allow the side of the carton to be generally 
flat in the formed carton. 
Each of sides 22 and 24 of the periphery of core 16 include first and 
second, parallel, longitudinal stripper grooves 34 located parallel and 
adjacent to but spaced from the interconnections with top 26 and bottom 28 
at locations corresponding to the longitudinal path of hooks 36 of 
stripper bars 38 of the double package forming machine, with grooves 34 
having a width generally corresponding to hooks 36 of stripper bars 38 and 
particularly generally equal to or greater than hooks 36. Further, 
stripper grooves 34 have a longitudinal extent equal to the longitudinal 
extent of the longitudinal path of stripper bars 38 along mandrel 12. 
Prior forming blocks did not include stripper grooves and thus due to the 
close proximity of hooks 36 to the forming block necessary to catch on the 
free edges of the top flaps of the carton, hooks 36 were prone to engage 
the sides of the forming block when moving along their longitudinal path 
resulting in wear of hooks 36 and/or the sides of the forming block as 
well as metal filing contamination in the foodstuffs packaged in the 
formed double package. Grooves 34 allow hooks 36 to be located in very 
close proximity to sides 22 and 24 of mandrel 12 to insure hooking on the 
free edges of the top flap of the carton without engaging mandrel 12 to 
avoid the rubbing wear of prior double package forming machines. Further, 
grooves 34 provide forgiveness of any air trapped between the liner and 
sides 22 and 24 as will be explained further hereinafter. 
Each of sides 22 and 24 include first and second, spaced, air vent holes 40 
extending through the periphery of core 16 and located adjacent to but 
spaced from the interconnections with top 26 and bottom 28 and from end 
30. In the preferred form, vent holes 40 are in air communication with 
stripper grooves 34. In the most preferred form, vent holes 40 have a 
diameter generally equal to the width of stripper grooves 34 and are 
located within the extent of stripper grooves 34. 
Bracket 18 in the most preferred embodiment is in the form of a generally 
flat, rectangular plate of a size larger than interconnecting portion 20. 
In the perimeter of bracket 18 outside of interconnecting portion 20, 
suitable apertures are provided for receipt of mounting bolts 42 and 
position locking pins 44. Thus, bracket 18 mounts mandrel 12 of forming 
block 10 in a cantilever manner to the double package forming machine, 
with end 30 being free. 
Interconnecting portion 20 may have any desired configuration such as the 
hollow parallelepiped configuration of the preferred form. In the 
preferred form, portion 20 includes two parallel sides 46 and 48 
interconnected to a top 50 and a bottom 52 arranged parallel to each other 
and joining sides 46 and 48 together, with top 50 and bottom 52 extending 
generally perpendicular to and between sides 46 and 48. In the most 
preferred form, sides 46 and 48 have a thickness a multiple of times 
greater than sides 22 and 24 while top 50 and bottom 52 are approximately 
50 thicker than top 26 and bottom 28. Top 50 and bottom 52 may include 
suitable mounting holes 54 for clamp bars or like apparatus for use in the 
double package forming machine, not shown. The hollow interior of 
interconnecting portion 20 has a cross sectional area of a size 
substantial to the cross section of the double package desired to be 
formed, and preferably of a cross sectional area generally equal to or 
larger than the cross sectional area of the hollow interior of core 16. In 
the preferred form, each of sides 46 and 48 include first and second 
apertures 56 providing air communication to the hollow interior of 
interconnecting portion 20 and core 16. Apertures 56 should have a total 
cross sectional area generally equal to or exceeding the cross sectional 
area of the hollow interior of interconnecting portion 20 and/or core 16. 
It can be appreciated that apertures 56 and the hollow interior of 
interconnecting portion 20 provides communication of ambient air to the 
hollow interior of core 16 of mandrel 12 and at an air flow rate generally 
equal to the air flow allowed through the hollow interior of core 16. 
In the most preferred form, mandrel 12 is one piece and may be formed by 
two or more pieces permanently secured together such as by welding. 
Further, mandrel 12 is formed of cast aluminum which is surface hardened 
and having a release coat to allow ease of non-stick sliding of the liner 
on mandrel 12 and to allow ease of removal of any excess adhesive which 
should remain on mandrel 12. In the most preferred form, mandrel 12 is 
hardcoat anodized and includes a TEFLON.RTM. coating as the release coat. 
Alternately, mandrel 12 can be formed of a plastic such as polyurethane 
formulated to have the required strength and wear characteristics. 
Furthermore, such plastics could be formulated to incorporate a release 
agent to allow ease of non-stick sliding of the liner on mandrel 12 and to 
allow ease of removal of any excess adhesive which should remain on 
mandrel 12. In addition to potential savings in the fabrication of mandrel 
12, plastic mandrels 12 would be of lighter weight than aluminum mandrels 
12 and would reduce the rotational and torque forces placed upon the 
turret of the double package forming machine upon which forming blocks 10 
are mounted. 
End piece 14 is secured to and partially closes open end 30 to provide 
spaced adhesive pressure strips 58. In the most preferred form, end piece 
14 is a rectangular plate corresponding to end 30 and having first and 
second sides 60 and 62, top 64, and bottom 66. Sides 60 and 62 include 
stripper grooves 68 in line with and contiguous with stripper grooves 34 
of mandrel 12. Likewise, top 64 includes a flap groove 70 in line with and 
contiguous with flap groove 32 of mandrel 12. The opposite sides of the 
outside face 72 opposite to mandrel 12 includes flap grooves 74 of a size 
for receipt of the bottom dust flaps attached to the ends of the carton 
and which are secured to the bottom flaps attached to the front and back 
of the carton. 
Apertures 76 extend through end piece 14 for providing air communication to 
the hollow interior of core 16 of mandrel 12. Apertures 76 are arranged to 
form spaced, parallel strips 58 therebetween. In the most preferred form, 
the carton adhesive is applied to the blank in lines which are parallel to 
top 64 and bottom 66 when the bottom of the carton is formed, such that 
strips 58 are linear extending between sides 60 and 62 and located to be 
overlaid by the carton and liner with the adhesive of the bottom of the 
carton located in line with strips 58. Specifically, in the preferred 
form, six apertures 76 are provided in a parallel arrangement, with the 
four outside apertures 76 being of a generally rectangular configuration 
and with the two central apertures 76 being of a generally square 
configuration. Further, in the preferred form, the ends of apertures 76 
along sides 60 and 62 decrease in size from face 72 to mandrel 12, with 
the thickness between apertures 76 and sides 60 and 62 of end piece 14 
being generally equal to the thickness of sides 22 and 24 at the face of 
end piece 14 abutting with core 16 of mandrel 12. The corners between 
sides 60 and 62, top 64, bottom 66, and face 72 may be chamfered in a 
similar manner as between sides 22 and 24, top 26, and bottom 28 of core 
16 of mandrel 12. End piece 14 may be secured in any suitable manner such 
as by bolts 78 extending through suitable apertures formed in end piece 14 
and threadably received in core 16 of mandrel 12. 
In the most preferred form, end piece 14 is one integral piece formed of 
hardened steel machined to the preferred configuration. End piece 14 can 
include a suitable, non-flaking coating to allow ease of non-stick sliding 
of the liner. 
It can be appreciated that vent holes 40 and apertures 76 provide 
communication of ambient air from the hollow interior of core 16 to the 
interior of the liner of the double package and at an air flow rate 
generally equal to the air flow allowed through the hollow interior of 
core 16 and interconnecting portion 20. 
Now that the basic construction of forming block 10 according to the 
preferred teachings of the present invention has been explained, the 
operation of forming block 10 in the double package forming machines can 
be set forth and appreciated. Specifically, when the formed package is 
being removed from block 10 by stripper bars 38, the piston effect of 
block 10 sliding from the formed package is eliminated. Particularly, as 
the formed package is withdrawn from block 10, ambient air is allowed to 
flow to the void between end piece 14 and the bottom of the formed double 
package through apertures 76 and vent holes 40, through the hollow 
interiors of core 16 and interconnecting portion 20, and through apertures 
56 and through stripper grooves 34 and 68. Since air flow into the double 
package as forming block 10 moves out of the double package is only 
slightly restricted by the cross sectional areas of end piece 14, core 16, 
and interconnecting portion 20, a vacuum is not created in the void which 
would otherwise tend to collapse the liner of the double package. 
Additionally, the chamfered corners of mandrel 12 and end piece 14, the 
release coat of mandrel 12 and coating of end piece 14, and the taper of 
mandrel 12 also assure the release and removal of the double package from 
forming block 10 without collapse of the liner of the double package. 
It can be appreciated that forming block 10 according to the preferred 
teachings of the present invention eliminates the need for compressed air 
to force the double package from forming block 10. This is particularly 
advantageous because the control mechanisms for turning the air flow on 
and off in sync with stripper bars 38 is no longer necessary and problems 
arising when the air was out of sync are eliminated. Likewise, the 
hardware necessary to plumb the air flow through the forming block and the 
mass associated therewith are also eliminated. The hollow nature of core 
16 and interconnecting portion 20 also eliminates mass especially at the 
free ends of forming block 10 to reduce the rotational and torque forces 
placed upon the turret of the double package forming machine upon which 
forming blocks 10 are mounted. 
Furthermore, as compressed air is not necessary, the cost in electricity or 
other energy in producing such compressed air is eliminated. Likewise, 
other problems created by the quality of compressed air such as 
contamination from oil or the like carried by the compressed air are also 
eliminated. 
Due to the ease of removal of the double package from forming block 10 
according to the teachings of the present invention without encountering 
problems of liner collapse as occurred with prior forming blocks, a 
tighter wrap of the liner and carton can be provided around forming block 
10 to create a higher quality and more consistent package. Consistent and 
high quality packages result in better packaging of the cereal, foodstuff, 
or the like and less consumer complaints relating thereto such as stale 
product, erroneous suspicion of a tampered product, or like complaints 
resulting from improperly sealed liners, with collapse of the liner being 
a major cause of improperly sealed liners. 
It can be further appreciated that forming block 10 according to the 
teachings of the present invention has no moving parts, requires no 
maintenance or adjustment, and is very durable. In this regard, prior 
forming blocks had removable wear plates at least at the corner of the 
forming block over which the side flap of the carton extended. Such wear 
plates are not utilized in forming block 10, thus eliminating this 
separable component, the screws utilized for securement, and the tapped 
holes in the forming block as well as the problems associated therewith 
such as unintentional separation of the wear plate during use of the 
forming blocks. Further, if it should become necessary to remove or 
replace forming block 10 on the double package forming machine, one person 
can lift and carry forming block 10 due to the reduced weight from prior 
forming blocks which required two persons to lift and carry. 
The use of stripper grooves 34 is further advantageous in that it allows 
the remaining portions of sides 22 and 24 to be flat. Thus, pressure may 
be easily applied such as by roller on the front and back of the carton to 
spread and adhere the lines of adhesive between the front and back of the 
carton and the liner. The ribbed outer surface of prior forming blocks 
made the application of such pressure more difficult. Although the ribbed 
outer surface did allow some air communication around the perimeter of 
prior forming blocks, the degree of communication provided was minimal 
compared to that provided b-y stripper grooves 34. Further, vent holes 40 
located in stripper grooves 34 also allow ambient air to travel from the 
interior of mandrel 12 to intermediate mandrel 12 and the liner of the 
double package through stripper grooves 34. 
Thus since the invention disclosed herein may be embodied in other specific 
forms without departing from the spirit or general characteristics 
thereof, some of which forms have been indicated, the embodiments 
described herein are to be considered in all respects illustrative and not 
restrictive. The scope of the invention is to be indicated by the appended 
claims, rather than by the foregoing description, and all changes which 
come within the meaning and range of equivalency of the claims are 
intended to be embraced therein.