This invention relates to methods and apparatus for folding sheet material to form a pleated packet of such size as to facilitate storage and transport thereof.

BACKGROUND OF THE INVENTION It is conventional to fold sheet materials in such manner as to form a packet of reduced area so as to facilitate the storage and transport of such packet.

One instance in which the folding of sheet material is desirable is in the case of bags of the kind which are needed to assist in providing sterile zones adjacent an area in which surgical or other procedures are performed. Bags of this kind frequently are closed except for an open mouth at one end bounded by an elastic strip which partially closes the bag, but enables the bag to be supported by a suitable frame with the mouth open to shield the adjacent area. Such bags frequently are of large area ranging from 2 to 4 feet in width and 6 feet or more in length. The handling of such bags in unfolded condition is awkward and the preservation of the sterility of such bags is difficult to maintain. Accordingly, it is desirable to fold the bag by forming a plurality of pleats therein and produce a reduced area packet which more easily can be stored, transported, and maintained sterile.

SUMMARY OF THE INVENTION Pliable sheet material is made into a bag having an open mouth at one end thereof which may be banded by elastic so as to cause the mouth to be urged toward a closed condition. The bag thus is formed of two layers of such sheet material and is closed along three of its sides, one of such sides constituting the bottom of the bag and the bottom being opposite the mouth. One closed side of the bag is introduced to a nip between a pair of rollers one of which constitutes a winding mandrel having openings in its surface in communication with a source of air pressure which selectively can be negative or positive. The mandrel is rotated so as to cause the bag to be wound convolutely into a roll, vacuum being applied to the bag via the openings in the mandrel to secure the sheet material on the mandrel and assure formation of a tightly convoluted roll. As the bag is rolled, an operator may maintain the elastically banded edge of the bag in stretched condition to avoid bunching of the sheet material.

Following completion of the roll the application of vacuum is discontinued and positive pressure is applied through the mandrel to the inner surface of the roll so as to enable the latter easily to be stripped from the mandrel. A clamp is applied to one end of the roll and the clamp moved in a direction

to strip the roll from the mandrel. The roll is transferred to a position in which a portion of the roll overlies a pleating station at which a plurality of blades may be operated sequentially to crease the bag and form a pleated packet having a plurality of adjacent pleats.

Following pleating of the roll the clamp is released and the pleated packet is ejected from the pleating station for packaging or storage.

THE DRAWINGS Apparatus especially adapted for use in performing the preferred method is disclosed in the accompanying drawings wherein: Figure 1 is a side elevational view of the apparatus; Figure 2 is a top plan view of the apparatus shown in Figure 1; Figure 3 is a fragmentary elevational view, on an enlarged scale, of the pleating station; Figure 4 is an elevational view of the apparatus shown in Figure 3, but from a position rotated through 90° ; Figure 5 is a fragmentary top elevational view on an enlarged scale of the pleating station illustrating the ejection of a pleated packet; Figure 6 is an isometric view, on an enlarged scale, of a portion of the pleating mechanism; and

Figure 7 is a view similar to Figure 1 of a modified embodiment.

THE PREFERRED EMBODIMENTS Apparatus constructed in accordance with the preferred embodiments of the invention comprises a winding or roll-forming station 1 and a pleating station 2, the roll-forming station being supported by a first frame section having members 3,4, and 5 and the pleating station being supported by a second frame section having appropriate vertical and horizontal frame members 6 and 7, respectively. The two frame sections are joined together in spaced relation by couplings 8.

The winding station 1 has a horizontal table top or platform 10 on which is mounted an idler roller 11 for rotation about a fixed axis. Directly above the roller 11 is a mandrel 13 journaled in a support 14 which is mounted for vertical movements via a guide 15 and a slide 16. The slide 16 is coupled by a linkage 17 to a pneumatic or hydraulic cylinder 18 by means of which the slide is vertically adjustable.

The mandrel 13 is coupled to an electric drive motor 19 via a transmission 20 of known construction and has a plurality of helically arranged openings 21 which communicate with an air pump 21 via a line 22. Suitable and conventional valving (not shown) enables the pressure of air at the mandrel openings 21 to be either negative or positive, as desired. As is

best shown in Figure 1 the mandrel 13 directly overlies the idler roller 11 so as to form a nip 24 therebetween. The height of the nip is adjustable via the cylinder 18.

The pleating station 2 comprises a base 26 coupled to a pneumatic or hydraulic cylinder 27 so as to enable the base 26 to be raised and lowered.

Carried by the base 26 is a plurality of uniformly spaced, upstanding vanes 28 which define a plurality of parallel, spaced apart slots 29 open at their upper ends.

Upstanding frame members 30 and braces 31 support a vertically shiftable frame 33 via couplings 34 and 35. The frame 33 has a cap 36 at its upper end.

The cap has a plurality of side by side, spaced openings for the accommodation of a corresponding plurality of pneumatic or hydraulic cylinders 37 having piston rods 38 coupled at their lower ends to a corresponding plurality of pleating blades 39 which register with the slots 29. The frame 33 is vertically adjustable via a cylinder 40 that is secured to the upstanding frame member 30. Movements of the frame 33 are guided by one or more guide rods 41 which extend through the couplings 34, 35. The maximum height to which the frame 33 may be elevated is indicated by chain lines in Figure 1. The objective in elevating the frame 33 is to assist in the provision of a gap of predetermined height between the lower ends of the

blades 39 and the upper ends of the vanes 28, the purpose of which will be explained shortly.

A fine height adjustment for the frame 33 is provided by a hydraulic motor 42 carried by the frame and coupled by a drive transmitting belt and pulley assembly 43 to an adjusting screw 44 which extends through a threaded nut (not shown) fixed in the cap 36.

The fine adjustment controls the at-rest spacing between the frame 33 and the vanes 28, and the depth that the blades 39 may be plunged into the slots 29.

A reciprocable transfer carriage 45 is mounted on a track 46 for movements toward and away from the winding station 1 and the pleating station 2.

The carriage 45 includes a linear motor and a flexible electrical coupling 47 and supports a clamp 49 comprising a pair of claws 50,51 movable toward and away from one another by a pneumatic or hydraulic cylinder 52. The cylinder 52 is supported by an arm 53 coupled to the carriage 45 and is connected to a source of pneumatic or hydraulic pressure fluid in any conventional manner for the purpose of opening and closing the claws of the clamp.

The pleating station also includes ejecting means 55 for ejecting from the pleating station a pleated packet formed from a roll. The ejecting means comprises a bar 56 extending through an opening 57 in each of the vanes 28 and coupled to the piston rod 58 of a cylinder 59. The bar 56 normally occupies the

position shown in full lines in Figure 5, but in response to movement of the piston rod 58 in one direction, is movable to the position shown in chain lines in Figure 5 thereby enabling a pleated packet 60 formed from the rolled bag to be ejected from the pleating station to a position in which the packet may be gripped and removed by an operator.

To condition the apparatus thus far described for operation the mandrel 13 occupies the position shown in full lines in Figure 1 and the transfer carriage 45 and clamp 49 also occupy the positions shown in full lines in Figure 1. The sheet material from which the packet 60 is to be formed is positioned on the table top 10 so that one end of the material may be introduced to the nip 24 between the idler roller 11 and the mandrel 13. If the material comprises a bag, there will be two layers of such material introduced to the nip. However, it is possible to restrict the material to a single thickness if it is desired simply to form a packet from a single layer of sheet material.

As the one end of the sheet material is introduced to the nip the mandrel 13 will be rotated and negative air pressure or suction will be applied to the surface of the mandrel via the openings 21. The negative pressure will cause the sheet material to adhere to the surface of the mandrel so that the sheet material may be convolutedly wound about the mandrel and form a tightly wound roll. As the roll is formed

its diameter will increase and the position of the mandrel 13 may be adjusted vertically by the cylinder 18 to accommodate the increasing diameter.

When the sheet material has been wound to form a roll of desired diameter, the winding is terminated and positive pressure air is applied to the interior of the roll via the openings 21 in the mandrel. The positive pressure air will enable the roll easily to be stripped off the mandrel.

Following formation of the roll the base 26 and the pleating vanes 28 are lowered to a position which forms the aforementioned gap that enables free movement of the transfer carriage 45 and the clamp 49 across the pleating station to a position in which the claws of the clamp 49 may grip the adjacent end of the roll. The clamp claws are closed, thereby gripping or clamping one end of the roll. The carriage 45 then may be moved to the left, as viewed in Figure 1, transferring the roll to a position in which its left hand or leading end registers with the left-most vane 28. The blade 39 which is in register with the left- most slot 29 then may be plunged into such slot, thereby creasing and forming a pleat in that portion of the roll which overlies the slot 29 at the left hand end of the pleating station. As the blade 39 moves into the slot the leading end of the roll is stationary because it is clamped by the claws of the clamp.

Accordingly, the roll is further stripped off the

mandrel 13, thereby causing the trailing end to move to the left. Following the formation of the first pleat in the roll, the blade 39 which occupies the endmost slot 29 remains in that position and the next adjacent blade is moved into the associated slot so as to crease and form a second pleat in the roll. As the second pleat is formed, the first pleat remains in place in the endmost slot because of the presence therein of the associated blade 39. As the second pleat is formed, the roll is further stripped from the mandrel 13.

The pleating procedure is continued until each of the pleating blades 39 has been plunged into its associated slot 29 in succession, thereby converting the roll into the pleated packet 60.

Control of the sequence of movement of the blades 39 into the slots 29 may be provided in a selected one of a number of conventional ways.

At any time following the first or subsequent pleating operation the clamp 49 may be disengaged from the leading end of the roll and returned to its initial or at-rest position. Following completion of the pleating operation all of the blades 39 are moved vertically out of their associated slots to a position clear of the pleated packet. The ejecting mechanism 55 then may be actuated to eject the packet 60 out of the pleating station for removal by an operator.

Thereafter, the operation is repeated to form additional pleated packets.

The apparatus and sequence of its operation thus far described are for use in folding a flat sheet or a bag having its opening at the right hand end of the bag. It will be understood that, if the open end of the bag is at the right hand end of the pleating station, sequential movement of the pleating blades from left to right into the respective slots 29 will enable any air trapped in the bag to be expelled from the open end thereof as the pleating stages progress from left to right, as shown in Figure 1. In those instances in which a bag has its opening facing to the left, however, a different pleating sequence must be followed, thereby requiring a minor modification of the apparatus shown in Figure 7. Except for such modification, all other characteristics of the apparatus are as previously described.

In the modified apparatus shown in Figure 7 the pleating station 2 has a somewhat extended base 26a on which is supported an upstanding bearing wall 61.

The frame 33 is provided with a vertically extending support plate 62 that is secured to the frame and terminates at its lower end in a clamp 63. When the frame 33 is lowered to a position in which the blades 39 are in a position to enter the respective slots 29 the clamp 63 will bear upon the upper end of the bearing wall 61, as is shown in Figure 7.

In the operation of the apparatus shown in Figure 7, a bag is wound upon the mandrel 13 in the

same manner as described earlier to form a roll. The transfer carriage 45 is moved toward the pleating station 2 to a position in which the clamp 49 may engage the adjacent or leading end of a roll wound on the mandrel 13, following which the carriage 45 may be moved to the left a distance sufficient to enable the right hand or trailing end of the rolled bag to overlie the wall 61. At this time the carriage 33 may be lowered to a position in which the clamp 63 overlies and bears against the wall 61 so as to clamp the trailing end of the rolled bag firmly against the wall 61. At this time the clamp 49 may be activated so that the claws 51 release the leading end of the bag.

Following clamping of the trailing end of the bag to the wall 61 and release of the leading end of the rolled bag by the clamp jaws 51, the blades 39 may be plunged into the slots 29 sequentially from right to left, as viewed in Figure 7, thereby enabling the roll to be formed into the pleated packet 60. By commencing pleating from the trailing end of the rolled bag and continuing sequentially toward the leading end, whatever air is within the rolled bag will be expelled from the leading end thereof during the pleating operation.

Following forming of the packet 60 and returning of the transfer carriage to its initial position the frame 33 may be raised to unclamp the trailing end of the roll and raise the pleating blades

out of the slots. The ejecting mechanism 55 then may be actuated as described earlier to eject the packet from the pleating station, whereupon the operation may be repeated to form another pleated packet from a bag.

It will be understood that the movements of the movable parts of the apparatus may be controlled by electric motors or fluid actuators and that the necessary timing of the movements may be controlled by various switches or computer generated signals as is well known in the art.

The disclosed embodiments are representative of presently preferred forms of the invention, but are intended to be illustrative rather than definitive thereof. The invention is defined in the claims.