Cuffing finger and apparatus for cuffing bags in cartons

A cuffing assembly for flexible bags inserted into a receiving open carton includes cuffing fingers at each carton corner. The fingers are movable between a retracted position for insertion into a bag and an extended position in which they can overlap the carton corners. Air is discharged through air outlets adjacent the outer ends of the cuffing fingers to minimize frictional forces between the bag and cuffing fingers to prevent tearing of the bag as the cuff is being formed and during subsequent retraction of the cuffing fingers.

TECHNICAL FIELD 
This disclosure pertains to machinery for expanding and inserting empty 
flexible bags into an open carton. It specifically pertains to an improved 
cuffing finger and associated air supply for cuffing an open end of a bag 
about the opening of a receiving carton. 
BACKGROUND OF THE INVENTION 
This invention pertains to formation of a cuff about the opening of a 
plastic bag used as a liner for a receiving open carton. It arose from a 
need to facilitate the insertion and removal of cuffing fingers without 
tearing a bag during and after formation of the cuff. Such lined carton 
assemblies are widely used for packing of fresh meat and other food 
products. 
The present disclosure constitutes an improvement in bag cuffing equipment 
of the type generally disclosed in U.S. Pat. No. 5,100,370, issued Mar. 
31, 1992, which is hereby incorporated into this description by reference.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
This disclosure of the invention is submitted in furtherance of the 
constitutional purposes of the Patent Laws "to promote the progress of 
science and useful arts" (Article 1, Section 8). 
The present improvement can be utilized in a variety of machines designed 
for inserting bags into open cartons. The present improvements pertain to 
the structure and operation of cuffing fingers, such as those described in 
the U.S. Pat. No. 5,100,370. The improved cuffing fingers are applicable 
to any bag cuffing assembly using insertable cuffing fingers to invert the 
bag opening about the open periphery of a receiving carton. While 
disclosed specifically in relation to the previously-patented dual cuffing 
fingers, this improvement is not to be limited to any particular cuffing 
finger configuration. One familiar with the present development of bag 
inserter machinery will readily understand the application of the present 
improvements to such equipment. 
This invention can best be understood from a review of the machine 
components shown in FIG. 1. The inserting and cuffing apparatus is mounted 
on a supporting machine framework. Incoming open cartons 13 are fed along 
framework 10 by a powered conveyor 12. They are guided between stationary 
rails 11 fixed to the framework. 
Each open carton 13 is individually aligned in a stationary loading 
position facing a movable mandrel 14. The mandrel is insertable 
progressively into an open bag 17 and the facing open carton 13 axially 
aligned with the mandrel. After the bag reaches the bottom of the carton, 
the open end of the bag is cuffed about the perimeter of the open carton 
in preparation for loading of product. 
Mandrel 14 is shown as being constructed from a plurality of diagonal 
plates 15 adapted to individually bisect the corners of a receiving carton 
13. Each plate 15 includes an open vertical leg and an integral horizontal 
leg extending inwardly across the outer or bottom end of mandrel 14. The 
four plates illustrated in FIG. 1 are joined to one another at a central 
block 16 to form a unitary mandrel structure conforming to the shape and 
size of the interior surfaces of a receiving carton 13. 
The open upper end of each bag 17 is cuffed about the carton by movable 
cuffing fingers 22 located axially inward from the mandrel 14. A pair of 
cuffing fingers 22 are provided along each corner of mandrel 14. Each pair 
of cuffing fingers 22 are arranged to span one corner of a receiving 
carton 13. The individual cuffing fingers in each pair are arranged at 
opposite sides of the respective mandrel plates 15. They move inwardly and 
outwardly in directions parallel to the adjacent plates 15 as they pivot 
relative to axes perpendicular to the plates. 
Actuating means is operably connected to each pair of cuffing fingers 22 
for selectively moving the individual cuffing fingers between a retracted 
position and extended position. The actuating means is illustrated by 
small cylinders 23 connected by linkages to the paired fingers 22, which 
in turn are pivotally connected at their upper ends to a supporting 
movable frame 18. The retracted position is located within the exterior 
confines of mandrel 14 to facilitate initial placement of the mandrel 14 
and cuffing fingers 22 within a receiving bag 17 in preparation for 
subsequent insertion of the bag 17 within a receiving carton 13. While in 
the extended position, each finger 22 overlaps an outer side wall of a 
receiving carton at locations adjacent to its corners. The extended 
position of each cuffing finger 22 spreads the open end of the bag 17 and 
inverts the open end of the bag over the top edges of the carton 13 as the 
bag 17 is inserted within it. The extended fingers 22 produce a 
surrounding "cuff" about the carton opening, with the upper edge of the 
bag 17 facing upwardly about the periphery of the extended fingers 17. 
Frame 18 is vertically movable relative to framework 10 by means of a main 
cylinder 19 operably connected between them. The housing of cylinder 19 is 
fixed to framework 10. Its reciprocating piston is mounted to frame 18 at 
its lower end. 
A secondary cylinder 20 is operably connected between frame 18 and mandrel 
14. The upper end of the cylinder housing is fixed to the frame 18. The 
lower end of its piston rod is fixed to the center block 16 of mandrel 14. 
The entire inserting and cuffing assembly is centered along a mandrel axis 
illustrated in FIG. 1 by the line X--X. 
The improvements to the cuffing fingers 22 are shown in FIGS. 1 and 6. Each 
cuffing finger 22 is formed as an elongated rod centered along a straight 
axis Y--Y. The rod can be made from any suitable material, such as metal 
or plastic. It should be substantially rigid, and is preferably 
cylindrical in shape. Its outer end is covered by a plastic sleeve 30 
having a rounded end to minimize tearing of bags. The rod includes an 
axial central bore, shown at 31, which serves as a conduit for compressed 
air delivered to the cuffing finger to reduce friction about the cuffing 
finger as a bag is engaged by it. 
An axial aperture 32 is formed through the outer end of sleeve 30 in 
alignment with the bore 31. The end opening of bore 31 and the aperture 32 
form an air outlet adjacent to the outer end of the rod for discharge of 
air into a bag as a cuff is being formed. 
While a single axial air outlet is illustrated at the end of each cuffing 
finger, it is to be understood that other forms of air outlets are 
applicable to this invention. As examples, the rod (and sleeve 30) might 
be provided with a plurality of air openings along their outer ends, or 
the sleeve 30 might be porous to distribute air in a film about its 
surface areas in contact with a bag. The precise manner in which air is 
discharged at the outer end of each cuffing finger is largely a matter of 
choice and machine design. 
Compressed air can be supplied to the individual cuffing fingers 22 from a 
suitable air source 33 and control valve 34 by distribution manifolds 35 
and supply hoses 36 located on the mandrel 14 (see FIG. 1). 
The discharge of compressed air through each cuffing finger 22 creates an 
air film between the contacting sleeves 30 and the bag surfaces as the 
cuff is being formed. This significantly decreases the frictional forces 
imparted to the plastic film and reduces tearing. It also facilitates 
escape of the cuffing fingers 22 from formed cuff as the mandrel 14 is 
retracted at the completion of cuff formation. 
While the discharge of air can be continuous during operation of the 
cuffing mechanism, it is preferable to program operation of valve 34 to 
supply air to the outer ends of cuffing fingers 22 while the cuffing 
fingers 22 are in their extended positions substantially parallel to axis 
X--X. 
The method of inserting and cuffing bags to line a rectangular carton 
according to this invention is diagrammatically illustrated in FIGS. 2-5. 
FIG. 2 shows the above-described components in their initial positions 
prior to placement of a bag about the mandrel 14. 
Operation of the apparatus is initiated by activating main cylinder 19 to 
lower the frame 18 and extended mandrel 14 downwardly, placing the mandrel 
14 within an open bag 17 as it approaches the awaiting carton 13 on 
conveyor 12 (FIG. 3). During this movement, the lower ends of the fingers 
22 slightly overlap the upper ends of the mandrel plates 15. The fingers 
22 are in their retracted positions radially within the confines of the 
mandrel 14 and are located within the interior of bag 17. 
FIG. 4 shows the bag 17 fully inserted within carton 13. When the bottom 
edges of mandrel 14 engage the bottom of the carton 13, the secondary 
cylinder 20 is actuated to retract its piston and shorten the distance 
between the bottom of mandrel 14 and the frame 18, which continues to move 
downwardly. When mandrel 14 reaches the bottom of carton 13, the actuator 
cylinders 23 are powered to pivot fingers 22 to their extended positions 
(parallel to axis X--X). In these positions, the fingers 22 are aligned 
outwardly along the outer surfaces of the carton sides. Operation of valve 
34 should be timed to initiate discharge of air through the cuffing 
fingers 22 simultaneously with this motion. 
FIG. 5 shows completion of the cuffing operation, which occurs as the 
fingers 22 push downwardly along the opening of bag 17 to invert it over 
the top edges of the carton 13 and the bottom ends of the fingers 22. 
After completion of the inserting and cuffing operations as shown in FIG. 
5, the secondary cylinder 20 is expanded to remove fingers 22 from within 
the cuffed bag opening. They are then retracted. The continuing supply of 
discharged air about the cuffing fingers 22 assures smooth removal of the 
cuffing fingers 22 from the cuffed bag without tearing. Main cylinder 19 
is subsequently activated to remove mandrel 14 from within the lined 
carton 13. 
In compliance with the statute, the invention has been described in 
language more or less specific as to structural features. It is to be 
understood, however, that the invention is not limited to the specific 
features shown, since the means and construction herein disclosed comprise 
a preferred form of putting the invention into effect. The invention is, 
therefore, claimed in any of its forms or modifications within the proper 
scope of the appended claims appropriately interpreted in accordance with 
the doctrine of equivalents.