US3540187A

US3540187A - Apparatus for packaging products

Info

Publication number: US3540187A
Application number: US720233A
Authority: US
Inventors: Alfred C Monaghan
Original assignee: Weldotron Corp
Current assignee: WELDOTORON Corp; Weldotron of Delaware Inc
Priority date: 1968-04-10
Filing date: 1968-04-10
Publication date: 1970-11-17
Anticipated expiration: 1987-11-17
Also published as: GB1261794A; FR2005949A1; DE1918037A1; SE364914B

Description

1970 A. c. MONAGHAN APPARATUS FOR PACKAGING PRODUCTS 2 Sheets-Sheet 1 Filed April 10, 1968 INVI'JNIOR. ALFRED C. MONAGHAN 3 Q www Tw m 5 Q m I I haw,

Tm NQ T fiul a ATTORNEY NOV. 17, 1970 V c, MONAGHAN 3,540,187

APPARATUS FOR PACKAGING PRODUCTS Filed April 10, 1968 2 Sheets-Sheet 2 INVICN'I'OR. ALFRED -c. MONAGHAN ATTORNEY United States Patent O US. CI. 53-74 11 Claims ABSTRACT OF THE DISCLOSURE A product wrapping system includes means for detecting the length of the product, for providing a sheet of film of appropriate length and for feeding the sheet so that the leading end portion of the sheet underlies the trailing end of the product, for wrapping the trailing end of the sheet over, around and under the leading end of the product so that the trailing end of the sheet underlies the leading end of the product and the leading end of the sheet, to provide a sleeve wrap around the product. The system also includes means for folding down the open ends of the sleeve and for laying these folded down ends under the product in overlapped relationship, to provide a product which is overwrapped on all four sides.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the packaging of articles in a web of sheet material.

Description of the prior art Many types of products are wrapped in transparent thermoplastic films. It is frequently required that the two pairs of mating edges of the film be overlapped and sealed in the process of forming the wrap. The overlap type of closure or seal is utilized to provide a high level of protection against the seepage of fluid matter out of or into the package. Frequently the articles may vary in dimension, e.g. length. A typical product employing such a packaging technique is the tray filled with fresh meat commonly sold in supermarkets. The width of the tray is generally standard, the length of the tray varies depending on the cut of meat packed. The butcher may prepare one cut for a short time, then subsequently prepare a different cut requiring a different package size. Presently, depending on the wrapping rate required, such wrapping is performed manually, semimanually, or on rather complex automatic equipment.

SUMMARY OF THE INVENTION It is an object of this invention to provide a relatively simple system for automatically providing the desired lap type overwrap. Another object is to provide such a system which will accommodate a varying range of package sizes.

A feature of this invention is a system which automatically detects the length of the product to be wrapped: automatically provides a web of sheet material of an appropriate length; automatically wraps the web around the product to form a sleeve with lateral openings and a transverse overlap seal. An additional feature of this invention is a system which automatically receives the sleeve wrapped product, and automatically folds over the ends of the sleeve to form a longitudinal overlap seal.

BRIEF DESCRIPTION OF THE DRAWING These and other objects, features and advantages of the invention will be apparent from the following specification ice thereof, taken in conjunction with the accompanying drawing in which:

FIG. 1 is a top plan view of an apparatus embodying this invention;

FIG. 2 is a side elevation view of the apparatus of FIG. 1;

FIG. 3 is an end cross-sectional view taken along the plane 33 of FIG. 1;

FIG. 4 is an end cross-sectional view taken along the plane 44 of FIG. 1; and

FIGS. 5 and 6 are side elevation views of a modification of the sleeve wrap apparatus of FIG. 1.

DESCRIPTION OF THE FIRST EMBODIMENT The products to be wrapped are sequentially disposed on an infeed conveyor 10. This conveyor includes two parallel spaced apart belts 12 and 14 passing around two rollers 16 and 18. The machine direction is defined as the direction of movement of each product as it is wrapped. A plurality of sensing switches are suitably mounted with their actuators extending up between the upper runs of the belts 12 and 14. The actuator of the switch 20 is adjacent the downstream end of the conveyor, the actuators of the switches 22, 24 and 26 are further upstream. When the leading (downstream) edge of the product 28 operates the actuator of the switch 20, the remainder of the product will overlap and actuate either the switch 22; or the switches 22 and 24; or the switches 22, 24 and 26, depending on the length of the product.

A porous belt 30 passes around two

rollers

32 and 34, at an angle to and beneath the belts 12 and 14. A plurality of hoppers or trays 36, 38 and 40 are disposed adjacent to and above the upper run of the belt 30. A like plurality of vacuum chambers 42, 44 and 46 are disposed immediately beneath the upper run of the belt 30, respectively adjacent the hoppers 36, 38, 40.

The vacuum chambers 42, 44 and 46 are open topped and are each coupled to a vacuum source 48 by a respective one of a plurality of solenoid operated valves 50, 52, 54. The solenoids are coupled to an electrical power source, not shown, by a switching matrix, not shown, which includes the switches 20, 22, 24, 26 and suitable AND and OR gates. When the product actuates the switches 20 and 22, the solenoid 54 is energized, to effect the evacuation of the vacuum chamber 46. When the product actuates the switches 20, 22, and 24, the solenoid 52 is energized, to effect the evacuation of the vacuum chamber 44. When the product is long and concurrently actuates the switches 20, 22, 24' and 26, the solenoid 50 is energized, to effect the evacuation of the vacuum chamber 42. A stack of long sheets of thermoplastic material is disposed in the hopper 36 with the leading lower edge portion of the stack bent up, and overlying a portion of the belt 30 and the vacuum chamber 42. A stack of medium length sheets is disposed in the hopper 38 with the leading lower edge portion bent up and overlying a portion of the belt 30 and the vacuum chamber 44. A stack of short sheets is disposed in the hopper 40 with the leading lower edge portion bent up and overlying a portion of the belt 30 and the vacuum chamber 46.

When a product on the belts 12 and 14 causes the evacuation of one of the open topped vacuum chambers, the vacuum is effective to cause the lowermost sheet in the respective stack to adhere to the porous belt 30 and to be drawn from the stack. The leading edge of the product and the leading edge of this sheet, which sheet is to serve as a wrapper for the product, are then fed to the next adjacent conveyor belt 56. The phasing of this feed is not critical and is advantageously set so that the leading edge of the product leads the leading edge of the sheet downstream in the machine direction by a distance slightly less 3 than one half of the length of the product. Thus, as the product rides onto the conveyor 56, the trailing portion of the underside of the product will rest on the leading portion of the sheet 76.

The belt 56 passes around two rollers 58 and 60. Two sets of four sprocket wheels each 62A, 62B, 62C, 62D and 64A, 64B, 64C and 64D are journaled n suitable stub shafts on each side of the belt 56. An endless chain 66 passes around the sprocket wheels 62A D, and an endless chain 68 passes around the sprocket wheels 64A D. Two pairs of flights or rods 70 are supported by and between the endless chains 66 and 68. A photocell 72 and a photodetector 74 are disposed on a line between the conveyors 12/14 and 56. When the product 28 moves from the conveyor 12/ 14 onto conveyor 56 its trailing edge unblocks the light beam between the photocell and the detector which operate a relay circuit and drive, not shown, coupled to the sprocket wheels 62A and 64A, to cause the chains 66 and 68 to move in the clockwise direction as shown in FIG. 2 a distance equal to one-half their periphery. In so doing the flights 70 which are initially disposed at a station A at the upstream end of the conveyor 56 swing up, around and down to a station B at the downstream end of the conveyor 56, engaging the sheet of film 76 which has been advanced by the conveyor belt 30, and wrapping the trailing end of the sheet 76 about the product, leaving this trailing end dangling down in the gap between the conveyor '56 and the next conveyor 80.

The conveyor belt 80 passes around two rollers '82 and 84. A hot plate 86, which may be electrically powered, is disposed under the upper run of the belt 80. The belt 80 may be made of a suitable heat transmitting yet heat resistant material, such as silicone rubber. As the product advances from the conveyor 56 to the conveyor 80, the trailing portion of the sheet of film laps around and under the leading edge of the product, overlaping the leading portion of the sheet of film which is already on the underside of the product. As the package then passes over the hot plate 86, the overlapped leading and trailing portions of the sheet of film on the underside of the product are sealed together. At this stage of its travel the product now has a sleeve or cylindrical section of film formed thereabout which extends beyond the product on both sides. If merely a sleeve wrap is desired the conveyor 86 may discharge the sleeve wrapped product from the system. If a shrunk sleeve is desired, the conveyor may discharge the sleeve wrapped product to a heat shrink tunnel, such as shown in US. Pat. No. 3,222,800, issued M. Siegel et al., on Dec. 14, 1965. If a four sided overlap is desired, the conveyor 80 may discharge the product to a side wrapping system such as 90.

The side wrapping system 90 comprises two spaced apart infeed conveyor belts or

chains

92 and 94 which are respectively passed around sheaves or

sprocket wheels

96, 98, 100 and 102. The

wheels

96 and 100 may be fixed to the common shaft 104 which is suitably journaled, and the

wheels

98 and 102 may be fixed to a common shaft 106 which is suitably journaled. A pair of spaced apart

belts

108 and 110 straddle the infeed conveyor belts, and provide a sleeve folding function. The folding belt '108, which is endless, preferably is of circular cross section, and passes around a horizontally journaled sleave 112 at its upstream end and around a horizontally journaled sheave 114 at its downstream end. The upper run of the belt 108 comes off the top of the sheave 112, passes over a horizontally journaled sheave 116, under a horizontally journaled roller 118, under, around and back over the sheave 114, and against a vertically journaled sheave 120, and under and around the roller 112. The folding belt 110, which is endless, preferably is of circular cross-section, and passes around a horizontally journaled sheave 122 at its upstream end and around a horizontally journaled sheave 124 at its downstream end. The upper run of the belt comes oil? the top of the sheave 122, passes under a horizontally journaled roller 126, over a horizontally journalcd sheave 128, under a horizontally journaled roller 130, under, around and back over the sheave 124, against a vertically journaled sheave 132, and then under and around the sheave 122. As will be seen in FIG. 2, the

sheaves

116 and 128 are disposed above the base level of the product. The

sheaves

120 and 132 are disposed at the base level of the product, the rollers 118 and are disposed at the base level of the product. The sheaves 114 and 124 are disposed just below the base level of the product. The sheave 116 is disposed upstream in the machine direction of the

sheaves

98 and 102, while the corresponding sheave 128 is disposed downstream of the

sheaves

98 and 102. The sheave 120 is disposed upstream of the corresponding sheave 132. The

rollers

118 and 130 are substantially in line. The sheaves 114 and 124 may be fixed to a common shaft and are relatively closely spaced to converge the belts 108 and 110- at the downstream end of the system 90. As the packages proceed under the two round folding belts, the belts fold the upper layer of the film down. At this stage, the product is supported on the upper runs of the two

support chains

92 and 94. When the folding belts are flush with the base of the product, the film has been folded down to 90, as shown in FIG. 3. The lower layer of film is now pushed down by the upper layer of film and the folding belts continue to descend as they travel downstream in the machine direction until the upper surface of the folding belts are level with the base of the product. At this stage, the folding belts begin to converge, and the support chains end. The product transfers onto the folding belts and as these belts continue to converge, the film, which has already been folded down, is now folded under the product, as shown in FIG. 4. The belts are staggered in their convergence so that the folding belt 108 folds its side down and under first and the belt 110 folds its side down and under subsequently, so that the two sides will overlap without interference. The system 9 0 then discharges the product to the next conveyor belt 150. The conveyor belt passes around two

rollers

152 and 154. A heating plate 156, which may be electrically powered, is disposed under the upper run of the belt 150. The belt 150 may be made of suitable heat transmitting, yet heat resistant, material. As the product passes over the heated belt 150 the heat seals all of the underwrapped layers together to provide a fully sealed package. If a heat shrink package is desired the system may discharge the wrapped product to a heat shrink tunnel as previously described.

DESCRIPTION OF THE SECOND EMBODIMENT An alternative system for providing sheet film for wrapping from a continuous film supply roll rather than from a stack of pre-cut sheets is shown in FIGS. 5 and 6. An input conveyor belt 200 passes around two

rollers

202 and 204. A porous belt 206 passes around two

rollers

208 and 210. A vacuum chamber 212 is disposed beneath the upper run of the conveyor belt 206. A continuous web of sheet material 214 unwinds from a supply roll 216 which is disposed on a shaft 218, passes around a guide roller 220, around a guide roller 222, between two pinch rollers 224 and 226, between two wedge shaped

air ducts

228 and 230, onto the upper run of the conveyor belt 206. The upper pinch roller is supported between a pair of arms 232 which are pivoted on a shaft 234 for rocking motion. The lower ends of the arms 232 are coupled to the piston 236 of a solenoid valve operated air cylinder 238. The upper ends of the arms 232 support a radiant heat cut-01f element 240, such as electrically powered resistance wire, such as is shown in US. Pat. 3,135,077, issued to M. Siegel et al., on June 2, 1964. The pinch roller 224 is driven by a suitable drive, not shown. A photocell and a photodetector 250 provide a light beam across the upper run of conveyor belt 200 slightly upstream of its downstream end. A clamping pad 254 may be disposed above the web of sheet material 214 and the lower end of the arms 232 may also support a pressure pad 256 below the web in line with the pad 254.

When a product interrupts the light beam, the photodetector operates a suitable relay, not shown, which actuates the solenoid valve of the cylinder 238 to cause the cylinder to release the pressure pad 256 from the web and the clamping pad 254, while concurrently pinching the web between the pinch rollers 226 and 224. The pinch rollers advance the web between the wedge shaped

pressurized ducts

228 and 230, which ducts are coupled to a source of positive air pressure, not shown. The air flow supplied by the ducts floats and guides the web between the ducts and onto the upper run of the conveyor belt 206. The relay also operates a solenoid operated valve 260 which couples the vacuum chamber 212 to a suitable source of pressure, not shown. After the predetermined length of film has been fed out, which may be controlled by a series of switches in a switch matrix such as was described with respect to FIG. 1, the solenoid operated valve now causes the piston 236 to extend, clamping the film between the pads 254 and256, releasing the pinch rollers 226 and 224 and bringing hot wire 240 down onto the film which is tensioned between the pads 254/ 256 and the moving belt 206, thereby cutting the web which continues to be fed by the belt 206 for wrapping around the product as described with respect to FIG. 1.

While there have been shown and described preferred embodiments of the invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that in the illustrated embodiments certain changes in the details of construction and in the form and arrangement of the parts may be made without departing from the underlying ideal and principles of this invention Within the scope of the appended claims.

What is claimed is:

1. Apparatus for wrapping a product in a sheet of material comprising; means for conveying the product along a path in the machine direction; a first station on said path, and a second station on said path downstream of said first station; means for providing a sheet of material having a length adequate to form a sleeve around the product, and for conveying the leading end of the sheet from below said path into said first station to the underside of the product while the product is passing through said first station, whereby the leading end of the sheet underlies the trailing end of the product; means independent of said product conveying means disposed between said first and second stations, movable in an endless path separate from the path of movement of said conveying means for engaging the trailing end of the sheet at said first station, after the product has passed through first station, and before the product has reached said second station, and for conveying the trailing end of the sheet up behind, over the top, and down in front of the product, through said second station and transversely of and beneath said path, so that, subsequently, as the product passes through said second station, the trailing end of the sheet is pulled under the leading end of the product by the operation of the conveying means at said second station, forming a sleeve about the product.

2. Apparatus for wrapping a product in a sheet of material comprising; means for conveying the product along a path in the machine direction; a first station on said path, and a second station on said path downstream of said first station; means for providing a sheet of material having a length adequate to form a sleeve around the product, and for conveying the leading end of the sheet from below said path into said first station to the underside of the product while the product is passing through said first station, whereby the leading end of the sheet underlies the trailing end of the product; means disposed between said first and second stations for engaging the trailing end of the sheet at said first station, after the product has passed through first station, and before the product has reached said second station, and for conveying the trailing end of the sheet up behind, over the top, and down in front of the product, through said second station and transversely of and beneath said path, so that, subsequently, as the product passes through said second station, the trailing end of the sheet is pulled under the leading end of the product by the operation of the conveying means at said second station, forming a sleeve about the product, said conveying means comprising first, second and third conveyor systems disposed in line; said first station being disposed between said first and second conveyor systems; said second station being disposed between said second and third conveyor systems; and said means for engaging the trailing end of the sheet comprising a fourth conveyor system operative up through said first station, over said second conveyor system, and down through said second station.

3. Apparatus according to claim 2 wherein said path is horizontal; and

said fourth conveyor system includes an elongated member horizontally supported for movement by support means up between said first and second conveyor systems, over said second conveyor system, and down between said second and third conveyor systems.

4. Apparatus according to claim 3 wherein:

said fourth conveyor system support means comprises a pair of spaced apart, parallel, congruent, endless chains, straddling said second conveyor system; and

said elongated member comprises a rod coupled to and between said pair of chains.

5. Apparatus according to claim 1 wherein said sheet providing means comprises:

a porous conveyor belt disposed below said path, having one end thereof extending up into said first station;

a vacuum chamber disposed beneath the upper run of the conveyor belt, coupled to means for effecting the evacuation of said chamber and thereby providing suction through the adjacent portion of said conveyor belt; and

means for supporting a sheet adjacent said portion of said upper run of said belt, whereby when said chamber is evacuated, the suction through said portion is effective to adhere at least a portion of the sheet to said belt, so that said belt conveys the leading end of the sheet up into said first station and said path.

6. Apparatus for wrapping a product in a sheet of material comprising: means for conveying the product along a path in the machine direction; a first station on said path, and a second station on said path downstream of said first station; means for providing a sheet of material having a length adequate to form a sleeve around the product, and for conveying the leading end of the sheet from below said path into said first station to the underside of the product while the product is passing through said first station, whereby the leading end of the sheet underlies the trailing end of the product; means disposed between said first and second stations, movable for engaging the trailing end of the sheet of said first station, after the product has passed through first station, and before the product has reached said second station, and for conveying the trailing end of the sheet up behind, over the top, and down in front of the product, through said second station and transversely of and beneath said path, so that, subsequently, as the product passes through said second station, the trailing end of the sheet is pulled under the leading end of the product by the operation of the conveying means at said second station, forming a sleeve about the product, said conveying means comprising first, second and third conveyor systems disposed in line; said first station being disposed between said first and second conveyor systems; said second station being disposed between said second and third conveyor systems; and said means for engaging the trailing end of the sheet comprising a fourth conveyor system operative up through said first station, over said second conveyor system, and down through said second station; said sheet providing means comprising a porous conveyor belt disposed below said path having one end thereof extending up into said first station, a plurality of vacuum chambers, each disposed beneath said upper run of said porous conveyor belt; a like plurality of means for supporting a respective like plurality of sheets, each sheet being of a difierent length; and means for detecting the length of the product and in response thereto for selectively causing one of the vacuum chambers to be evacuated, so that a sheet of appropriate length is adhered to the porous belt.

7. Apparatus for wrapping a product in a sheet of material comprising: means for conveying the product along a path in the machine direction; a first station on said path, and a second station on said path downstream of said first station; means for providing a sheet of material having a length adequate to form a sleeve around the product, and for conveying the leading end of the sheet from below said path into said first station to the underside of the product while the product is passing through said first station, whereby the leading end of the sheet underlies the trailing end of the product; means disposed between said first and second stations for engaging the trailing end of the sheet at said first station, after the product has passed through first station, and before the product has reached said second station, and for conveying the trailing end of the sheet up behind, over the top, and down in front of the product, through said second station and transversely of and beneath said path, so that subsequently, as the product passes through said second station, the trailing end of the sheet is pulled under the leading end of the product forming a sleeve about the product, said sheet providing means comprising a porous conveyor belt disposed below said path and extending up into said first station, a vacuum chamber disposed beneath the upper run of the conveyor belt, coupled to means for efiecting the evacuation of said chamber and thereby providing suction through the adjacent portion of the conveyor belt; means for supplying a continuous web of sheet material; first means for conveying the leading end of the web to said portion of said belt adjacent said vacuum chamber; second means for clamping a mediate portion of the web; said first and second means being alternatively operable; and third means for severing the leading end portion of the web from the mediate portion of the web, operative concurrently with said second means.

8. Apparatus according to claim 7 wherein:

said supply means includes a roll of said sheet material;

said first means includes a pair of driven pinch rollers,

and a pair of spaced apart air ducts coupled to a source of positive air pressure;

said second means includes a pair of clamping members; and

said third means includes an elongated, radiant heat source.

9. Apparatus according to claim 2 wherein said third conveyor system includes a heat source for sealing the ends of the sheet beneath the product.

10. Apparatus according to claim 2 wherein the sleeve has open ends extending beyond the product, and further including:

a fourth conveyor system disposed in line with said third conveyor system;

said fourth conveyor system including:

first folding means for initially folding down and under the product one of the overextending ends of the sleeve, and

second folding means for subsequently folding down and under theproduct the other of the overextending ends of the sleeve.

11. Apparatus according to claim 10 wherein said fourth conveyor means further includes:

a first pair of spaced apart conveyor chains extending in the machine direction from the downstream end of said third conveyor system to an intermediate stage in the length of said fourth conveyor means in the machine direction;

said first and second means comprise a second pair of spaced apart endless belts, each having a first portion straddling said first pair of chains and a second portion extending and converging downstream in the machine direction beyond said first pair of chains;

said first portion of each belt having a lower run descending towards the upper runs of said first pair of chains;

said first portion of each belt having a lower run descending towards 'the upper runs of said first pair of chains;

said second portion of each belt having an extension of said lower run of said first portion which is coplanar with the upper runs of said first pair of chains, and having an extension of said upper run of said first portion which passes through and below the plane of said upper runs of said first pair of chains;

' whereby said first pair of chains support and convey said sleeve wrapped product along said path in said machine direction while said lower runs of said first portion of said belts progressively ride down on and fold down the extending ends of the sleeve about said product, and said converging extension of said lower runs of said first portion in said second portion support and convey said product along said path in said machine direction while said extension of said upper runs of said first portion in said second portion fold the folded down ends of the sleeve under the product.

References Cited UNITED STATES PATENTS 3,250,053 5/1966 Hyer et al. 53-66 3,276,184 10/ 1966 Holt 53-2l0 X 3,287,876 11/1966 Willbrandt 53-33 3,355,166 11/1967 Plumb 53-389 X TRAVIS S. MCGEHEE, Primary Examiner N. ABRAMS, Assistant Examiner US. Cl. X.R.