CA1064380A - Automatic wrapping apparatus - Google Patents
Automatic wrapping apparatusInfo
- Publication number
- CA1064380A CA1064380A CA279,024A CA279024A CA1064380A CA 1064380 A CA1064380 A CA 1064380A CA 279024 A CA279024 A CA 279024A CA 1064380 A CA1064380 A CA 1064380A
- Authority
- CA
- Canada
- Prior art keywords
- film
- load
- clamp
- turntable
- hold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B53/00—Shrinking wrappers, containers, or container covers during or after packaging
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B11/00—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material
- B65B11/04—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material the articles being rotated
- B65B11/045—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material the articles being rotated by rotating platforms supporting the articles
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Basic Packing Technique (AREA)
Abstract
Abstract of the Disclosure An automatic wrapping machine comprising a film roll support adapted to hold a roll of film, a turntable adapted to hold a load of unitary members positioned adja-cent to the film roll support, a drive apparatus to rotate the turntable and a brake adapted to place tension on the film web of the roll of elastic stretchable material car-ried in the roll support. A clamp assembly is mounted adjacent to the load to hold the film while the turntable with associated load rotates allowing film to wrap around the load and the clamp assembly. The clamping assembly includes a pneumatic device for activating the clamp after the completion of at least one revolution of turntable so that the clamping assembly is retracted from the film overwrap. A film cutting and clamping mechanism is loca-ted adjacent to the turntable to cut the film web after the load is wrapped and holds the free end of the film in a secured position. The holding clamp subsequently clamps around the film to hold the same in position for the wrapping on the next load after it is in position.
Description
10f~43~30 The present invention relates to the automated unitiza-tion of multiple products into single loads that will maintain their unitary integrity throughout shipment. More specifically, this invention relates to a method and apparatus for dispensing and wrapping a stretchable film around a plurality of stacked units located on a rotatable turntable.
Automatic unitization of loads is currently being accomplished by various types of machines. Specific examples of such machines include strapping and string-tying equipment;
automatic taping machines; palletizers that glue the products together by automatically dispensing hot melt between the units as they are being palletized; automatic shrink film placing units that work in conjunction with shrink tunnels: and auto-matic dual roll push through types stretch film wrappers.
The currently used automatic stretch film placing units stretch the entire web of film at the same time to force it around the load and heat seal the ends of the film together. `
This apparatus has the disadvantage of requiring enormous forces . .
to stretch the film. In addition, the apparatus pulls the film across the corners of the load which may cause rupturing of the , film or deformation of the load. Most importantly, the process requires a critically important seal to reliably secure the load during shipment. If the heat sealing jaws of the apparatus do not provide a perfectly uniform pressure and temperature ,, along their entire length then the film seal will not be par-ticularly strong. Thus the seal will be overheated in some '' areas which will melt the film thin, or crystallize it to a '~ state of brittleness. Alternatively if the seal i9 underheated in some areas deterioration or unwrapping may occur under the ! 30 tension of shipment.
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~06~380 The present invention provides a process of making a unitary package from a load comprising a plurality of units com-prising the steps of placing successive loads on a conveying device; transporting one of the loads to a wrapping apparatus;
holding a leading edge of a stretchable elastic material in a clamp assembly positioned between the forward and trailing corners of the load in a fixed position adjacent to the load;
placing the stretchable material under tension to cause the material to be stretched while rotating the load and the clamp assembly to form an overwrap around the first load and clamp assembly to form a film wrap of at least one layer of stretched film material; releasing the leading edge of stretchable elastic material from the clamp assembly and retracting the clamp : assembly from the film wrap away from the load after the first ~ revolution of the load so that the clamp assembly is pulled out : of the film wrap and the stretched film assumes the former .
position of the clamp assembly to cover the area vacated by the clamp assembly; severing the stretched film material from the - wrapping apparatus to form a leading edge and a following edge of the wrapped load; and simultaneously clamping the leading edge with clamp assembly in a position to begin wrapping of the follow-ing load. .
The present invention further provides an automatic wrapping machine comprising a film support means adapted to dis-pense a roll of film, a turntable adapted to hold a load posi-tioned adjacent to thè film support means, means to rotate the turntable, brake means adapted to place tension on a film web of stretchable material, a clamp means mounted on the turntable adajcen' to the load to hold the film while the turntable with : 30 associated load rotates allowing film to wrap around the load and ~ - 2 -,, ~ .
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the clamp means, the clamp means including release means for releasing the clamp from the film web wrap after completion of at least one revolution of the turntable, a second clamp means mounted above the film web to hold the upper edge of the film means to move the first and second clamp means, the first and second clamp means being moveably mounted so that upon re-traction the turntable clamp means recedes from the film over-wrap below the bottom level of the edge of the film web over-wrap and the upper clamp means raises from the film web overwrap above the top level of the edge of the film web overwrap, a film cutting and clamping means positioned adjacent to the turntable, the film cutting and clamping means having means to cut the film web after the load is wrapped, clamp the free end ~-of the film in a secured position and position the film to be held by the turntable clamp means for the wrapping of the next load.
Preferably, the placing of the film web around the load in multiple layers requires considerably smaller forces to be used in order to obtain the film elongation as is required.
As the load is rotated on a turntable, the application of the film to the load mitigates the sliding or abrading of the film as conventionally occurs. No seals are required when "tacky"
film is utilized, as this type of film normally will have enough cling to bond to itself. In those instances where greater , fastening is required, a simple tack seal bonds the trailing edge of the film to the layers already disposed about the load.
As with the other types of machines the tack seal is completely automatic, which is a necessity in modern plants.
Preferably, the unitizing forces are spread over the product so that these forces are not concentrated at specific - 2a -10643~0;
points which often tends to deform the product. The conven-tional solution of this problem is for padding to be placed beneath the straps. This placement is invariably performed by hand and thus defeats the automatic feature of the operation.
The prior art also discloses the glueing of bags or boxes in order to unitize multiple products into a single load.
The glueing is frequently objectionable to the customers who must pull it apart and does not work particularly well when the product is column stacked.
As the film-holding clamp means of the present machine are wrapped and removed prior to final revolution, the clamp means can be positioned off the side of the conveyor, thereby eliminating the possibility of the pallet load hitting the clamp means.
U.S. Patent No. 3,867,806 discloses a process for making a unitary package in which a load comprising a plurality of units is formed by wrapping a band formed of plural layers ; of a stretched material around the units. This patent requires the holding of the film's leading edge against the vertical surface of the package load by either manual or other non-disclosed fastener means. In the preferred embodiment of the present invention clamps are located on the turntable and a top platen and serve to hold the leading edge of the film against the vertical side of the load to be wrapped. After the first layer of film is wrapped around the load and clamps, the clamps located on the platen and turntable are placed in retracted positions 50 that the load can be conveyed without interference from the clamps.
Upon completion of the fastening steps disclosed in United States Patent 3,867,806, the operator must sever the ' ' -.
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overwrapped package from the film dispenser by employing a drop-knife cutter means which is mounted adjacent the pallet support means. In the preferred embodiment of the present in-vention, film clamp/cutter jaws are used which serve to hold the film in a vertical position while a toothed film cutting bar pierces the entire vertical length of the film at the same instant~ In both cases, the elongation of the film is due to the tension imparted thereon by a tension brake acting on the dispensing roll. Prior to separation the amount of elongation is uniform along the vertical length of the package. In the prior art mode of cutting the film by a sIiding cutting knife, the tension is released and consequently the elongation de-creases as the cutting blade passes through the film. Thus the amount of elongation at the top of the film through which the blade has passed will be less than the elongation present at the bottom of the film, where the blade has yet to pass. This lack of uniformity can lead to the load having a non-uniform stretched film. Consequently a less functional wrap is produced which in addition is less aesthetically appealinq. Such appearance is critical in clear plastic wrapped packagP~. This is so in spite of the fact that the cutting operation is performed subsequent to the sealing operation. Conver~ely, the preferred embodiment of the present invention cuts the entire length of the film at one time, thereby keeping the amount of tension and percent of elongation constant and uniform along the length of the film.
` The uniformity of tension provides a more functional and aesthetically pleasing package. The effect of a onetime total - length cut is further enhanced when a tacky film is employed.
This particular type of film does not require any additional sealing means other than the wipe operation of a brush which ~- _ 4 _ .,~
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1064380 ! ~
secures the trailing edge to the vertical side of the package.
U.S. Patent No. 3,514,920 discloses an apparatus for overwrapping a package by means of a heat shrink film shrunk around a load to provide a unitary package. In that patent the heat-shrinkable plastic film used as an overwrap for the package has a substantially rectangular configuration and has a leading edge portion fastened against the cartons. It will be noted that this apparatus specifically requires the operator,to attach , the leading edge of the plastic film to the cartons. The pre-ferred embodiment of the present invention eliminates this manual operation. In addition to holding the leading edge of the film against the load, after the next load is in position, the clamp means grab and hold the new leading edge of the film in order to facilitate the package of the pallet and associated ~ -' load.
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The use and excessive cost of heat tunnels may be ',~ eliminated since the film web used is stretchable and conse-'~'' quently no heat is required to secure the package.
', United States Patent No. 3,793,798 discloses a shrink `^, 20 palletized process and apparatus. That particular package and ~' process also specifically contemplates the manual withdrawing of , .~, the leading edge of the film and holding that ~eading edge against the package.
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,j An additional advantage of the preferred embodiment of ' ~'I the present invention is the use of the upper platen clamp in ,~ conjunction with lower conveyor located clamp. The utilization ~; of the two clamps allows the film to be held firmly against the ~' '''' ', load at two points. This allows the package to be wrapped uni-formly with equal film tension and elongation along the entire length of the vertical sides of the load.
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~06438~) In previously developed stretchfilm wrapping machines, an edge of the film is either tacked or sealed to the previously wrapped film layers prior to the time of film cutting or separa-tion. This is required because it is necessary to maintain the backward tensio~ and consequently the elongation of the film prior to separation in order for a tight seal to be produced.
After the seal is formed, the film is cut. This leaves a por-tion of the film, i.e. between the seal and the trailing edge, as wasted film. This waste of film can now be avoided by cut-ting the film and subsequently wiping the film against the ver-tical side of the load thereby utilizing the entire film length in a functional capacity.
Other wrapping patents of general interest are Nos.
3,795,086 and 3,589,102. Patents which disclose the spiral wrap--ping of articles and are of interest are 2,575,467; 3,003,297;
3,788,199 and 3,863,425.
When the preferred embodiment is in use, a roll of clear stretchable film is held on a vertically arranged dispen-sing means. Film holding clamps are located upon an upper platen and along one edge of the rotatable load supporting turn-table. At rest, the platen and turntable film clamps are open, the platen is in its "up" position and the cutter clamp jaws engage the film. A load comprising a pallet and package units thereon is conveyed onto the turntable and stopped in the proper position when sensed by a photo-electric cell. Subsequently, the top platen is lowered to stabilize the load and the platen and turntable clamps close to clamp the film. These clamps are ;;designed to hold the film securely against the starting forces on the film and to be able to retract without tearing the film.
In normal operation, the clamps will be retracted after approxi-mately 1 1/4 turns of the turntable in order to allow the high-.
~ - 6 -est level of resultant tension on the load. The platen and turntable film clamps are retracted after 1 1/4 turns to allow subsequent layers to be wrapped directly against the load. The retraction of the clamps, prior to the final wrap layers, allows the film holding clamps to be placed on the side of the conveyor, free from damage by passing pallets. Additionally, the clamps are located at the mid-point of a side of the load in order to allow for maximum "forgiveness" in pallet alignment and register with respect to the leading edge of the film.
The cutter clamp jaws retract to their open position and the turntable rotates the load, which causes the film to be wrapped around the load. A film brake imparts a desired re-striction on the film roll to elongate the film and stretch it around the load. When the desired number of film layers are wrapped on the load, the turntable comes to a stop in its rest position. Additional cutting reliability may be achieved by .~.
automatically reducing or increasing tension to a given level in the last quarter turn to compensate for the type of film being -used.
A "U" shaped film clamping jaw is used to pull the ., film web into its cutting position for engagement with the blade holding film cutter/clamping jaw. As the two film cutter/clamp-; ing jaws close, a toothed vertical blade which extends beyond the edge of the jaws punctures the film as one of the horns of the "U" clamps the film against a rubber pad carried on the cutter/clamping jaw. Consequently, this clamping action holds the leading edge of the film in position for the wrapping of the succeeding load. Thus it can be seen that this system is ex-tremely versatile and reliable because it does not re-quire a precise alignment of blades; and is relatively independent of load size, configuration, rigidity or place-; 7 ~
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10~'~38() ment. As prevlously mentloned thls lnvention contemplatesthe use Or no electrical heating parts. I~ the cuttlng bar merely perforates the rllm and does not completely cut the film web, the movement of the existing load will tear the film apart between the perrorations. The film will then be wiped down rlat against the ~inished package by a ver-tically held brush. It will be appreciated that in most cases, the rilm will have sufricient tackiness so as not to require any further bonding. However, if necessary, a heat sealing operation can be added to the apparatus on the exit conveyor.
In an alternate embodiment, the apparatus is provided with a movable roll carriage in order to expand the machine's capabllitles to include spiral wrapping of very tall loads or random loads of varylng height. If such ls the case, the rllm web ls usually much narrower and there~ore, requires smaller forces to stretch it.
These smaller ~orces may ellminate the need ror the top platen for low production where the turntable rotation speed does not require a top platen ~or stabillty. The spiral wrap apparatus is nearly identical to the full web.
The ~ilm starting requlres only a bottom clamp, lr the splral ls to start and stop at the bottom! Conversely, lt requlres only a top clamp 1~ the film ls started and stopped at the top. The ldentical clamping/cutting mechan-,:
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iO64380 ism described ls also used for the splral conflguratlon and the clamping/cutting bar need not be any longer than ?
the web width of the film in order to perform its func-tion properly.
While the start and flnlsh of the splral opera-tion functions the same as the full web, the wrapplng process lends ltself to great versatility. If the mach-lne is to start and stop at the bottom of the machine, after the initial revolution of the turntable, the fllm roll is raised to spiral the film onto the load. Whlle ' ' at the top or bottom, any number of predetermlned wrap layers can be dispensed to hold and secure the produc~. ¦
The rate at which the film is raised and lowered deter~
mlnes the amount of fllm that wlll be dispensed. -The above mentioned purposes are more readily apparent when read in con~unctlon with the following de- `-'' ' ' talled description of embodiments of the present ln-vention.
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', BRIEF DESCRIPTION OF THE DRAWINGS
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Flgure 1 ls a perspective view Or the automatic wrapplng apparatus, outgoing pallet wlth wrapped load lo-cated thereon, and associated rotatable conveyor;
,, Figure 2 is a,top plan view, wlth top platen removed, of the wrapping apparatus with the pallet and ~, . .~, .
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10643~o load located on the turntable whlch has been rotated through 130 Or the first revolution of the wrap cycle;
Figure 3 is a top plan view, wlth top platen removed, of the wrapping apparatus wlth pallet and load located on the rotatable turntable, at the completlon of the wrap cycle:
Figure 4 is a top plan view of the film clamp/
cutter jaws showing the ~ilm location ~ust as the clamps are fully closed;
Figure 5 is a detailed top plan view of the film clamp/cutter Jaws showing the film location during the lmmediately succeeding step of the wrapping cycle as shown in Figure 4, Figure 6 is a perspective view of the turntable film clamps and top platen film clamps in their closed position;
Figure 7 is a perspective view of the film brake mechanism; and Figure 8 is,a perspective view Or the splral wrapping embodiment.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to the drawings and more particularly to Figure 1, there, is.illustrated a wrapped package 10 - , . - , . , . ~ . - ., -. - , ., . . .. -106~3~0 produced through use Or automatic wrappin~ apparat~s e~body-ing the present inventlon. The package 10 comprises a palletlzed load of boxes 11 located upon a conventlonal forklirt pallet 12. The vertically arranged portlon of the load is overwrapped by a band 14 formed of plural layers Or a stretchable sheet of materlal as for example P.V.C. The layers Or the stretchable material are se-cured together by the tackiness o~ the material to form a cumulatively homogenous band of ~ilm. The trailing edge of the film is likewise secured against the layer beneath it by brush 16.
Figure 1 shows the fllm dispenser apparatus 18 and the roll of film 20 ad~acent to rotatable turntable 22 which supports the load during the wrapping operation.
A first conveyor means 24 carries the palletized load ~. .
to the rotatable turntable 22. A second conveyor means 28 carries the wrapped palletized load O~r the rotatable . , .
turntable 22. A top platen 30 serves to stabllize the load during the wrapplng cycle. The top platen 30 is ~O ralsed or lowered by actuating air cylinder 32 which al-lows the platen to move up or down by slldlng along vertical slide bars 34 which are secured to the apparatus' vertical supports 36, 38. The air cylinder 32 is suppor-ted by bracket 101 which is ln turn supported by vertical support post 100. The top plater~ 30 1B held 1" relatlve `''; ' ' ,, .
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-` 10~31~0 suspended posltlon by a horizontal platen support arm 40 which is ln turn secured to the platen ca~riage 42.
The platen carrlage 42 slides along vertlcal sllde bars 34 on roller bearings (not shown).
The lower surface of the platen 30 ls composed Or a resilient materlal 56 so that when the platen ls lowered the load is not crushed by the platen's welght.
A set of platen film clamps 44 are pivotally secured to the rear vertical wall of the platen 30 as best seen in rigure 6. The rotary air cylinders 50 activate the platen film holding clamps 44 so that they spread apart.
Air lines 54 serve to actiYate the cylinders and are in communication with a source of pressure which is not shown.
An air sllp ring 88 allows the top platen 30 and its attached clamps 44 to rotate along with the load and still maintain the clamps in a closed or open posi- -tlon as desired. The coiled air line 90 runs along the platen support arm 40 to the air slip ring 88 which is --connected through lines 54 to the air cylinders 50 to film clamps 44. The use of the air slip ring allows the platen and clamps to be rotated while still main-taining the clamps in contact with the air supply. Rub-ber edges 52 secured to the clamps hold the fllm in place between the film clamps when closed.
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10~;~3~0 A set of fllm clamping/cuttlng ~aws 60 ana 62 ror clamping and cutting the film at the end of the wrap are held in vertical position by horizontal swing arms 66 and 64 respectively. The ~aws 60 and 62 are secured to the -horizontal swinging arms 66 and 64 by frontal holding bars 68. Air cylinders 70 are secured to the apparatus vertical supports 36 and 38 and serve to rotate the hori-zontal swinging arms 64 and 66 about vertical shaft 72 and 74, respectively by acting on cross support 80. The 1~ vertical shafts 72 and 74 are secured to brackets 76 which are in turn secured to apparatus vertical supports 36 and 38. The air cylinders 70 rotate the horizontal swinging arms 64 and 66 by acting upon a cross support 80 by means o~ sliding piston rod 82. Thus the horizontal arms ro-tate around the vertical shafts.
Electric photo¢ell 86 senses when the front of the load and pallet are in position and serves to stop the conveyor drive motor 92 to place the load and pallet in proper wrapp1ng position.
An electric drive motor 92 and connected gear reducer 94 drives the turntable rollers 96, which allows the palletized load to be stopped ln the proper position, and later to be moved when wrapped.
Turntable fllm clamps 102 are mounted on the slde vertical ed8e of the turntable, as beet seen ln Fig-~0643B0 ure 6. The pair Or clamps hinge at thelr pivot point and are activated by rotary alr cylinders 106. Rubber edges 104 serve to hold the film when the turntable clamps 102 are in their operative or closed position. It should be noted that when turntable clamps 102 are opened to re-lease the film the two Jaw segments each pivot open 90 so that the clamp ~aws are beneath the level of the turn-table.
Similarly when the platen clamps 44 are in open l~ position, the two ~aw segments each pivot 90 so that the clamp ~aws are above the level of the platen. The clamps - hold1ng the film are retracted after the film has been secured to the load by wrapping more than one revolution, so that the clamps do not interfere with the remainder of the wrapping process.
Figure 2 is a top view of the machine after 130 rotation of the first revolution of the wrap cycle. As is shown, the turntable clamp 102 holds the leading edge of the film 15 between rubber edges 104 as turntable 22 ~0 rotates to pull film ofr the film roll 20.
The film is placed under tension so that it stretches as it is being wrapped around the load. Rubber friction rollers 110 mounted on a rotatable shaft 112 en-gage the surface of the film roll to restrict the film ae it i9 bein8 unwounù. A brake 160 engagee the rotat-~0~; ~380 able shaft to llmlt the rotatlon of the shaft as the rol-lers are drlven by the rotatlng surface of the fllm roll thus allowing the deslred degree of tension to be applied to the film.
Figure 3 is a top vlew of the machine at the com-pletion of the wrap cycle. The left fllm clamp/cutter ~aw 62 is shown ln mid-stroke. Turntable film clamps 102 are open at thls point ln the cycle.
Figure 4 is a detailed top vlew of the film clamp/cutter ~aws 60 and 62 showing the film location ~ust as the clamps are fully closed. The left film clamp/cut- ~ -: . .
- ter J aw 62 comprises a support arm 68, a blade support bar : .- .
120 secured to the support arm, a toothed film cutting blade 122, a resillent film clamping pad 124 and a pad support bar 126. The cutting edge of the toothed film cutting blade extends beyond the forward edge Or the blade support bar 120. The right rilm clamp/cutter ~aw 60 is . . .
made up of a film web pusher bar 130, a clamp bar 132 -which is positloned across from bar 130 so as to create an open space 134 between them and a "U" shaped configura-tion. The fllm brush 16 is also secured to the right film clamp/cutter ~ aw 60 on arm 68 at the front-most por-tion of support bar 66. The operative edge 140 of the film web pusher bar 130 is arcuately shaped so a~ not to tear the film. The operative edge 142 of the clamp bar .
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L3~0 132 is rlat so as to engage and hold securely the film 15 against the resllient clamplng pad 124.
In operatlon, it can be seen that the entire width of the film web is easily and reliably clamped and cut in one single operation. The cutting and clamplng operation allow the film tension to be altered prior to the film being actually cut. With the film 15 drawn over the right fllm clamp/cutter ~aw 60 in the positlon shown ln Figure 3, the left ~ilm clamp/cutter ~aw 62 en-b gages it to clamp the film web between clamp ~aw 132 and resllient pad 124. As the resilient pad 124 is compres-sed the cutting edge of the toothed film cutting bar 122 punctures and cuts the film as it forces it apart in the space 134. Motion of the wrapped load on the turntable conveyor also can apply tension to the film so that it will be severed by the cutting bar 122. The film is held between the film clamp bar 132 and the resilient pad 124 whlch now becomes the leading edge of the film for the next succeeding load and pallet.
Severed film portion 144 becomes the trailing edge of the load belng wrapped. As previously mentioned, the ; turntable film clamps 102 and top platen clamps 44 are in the open positlon at this time in the cycle. The position of package units C, D and E is the same as in Figure 3.
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Flgure 5 ls the same view as Figure 4 durlng the following phase of the wrapping cycle, with the load 10 moving off of the rotatable turntable 22. Package .
unit D has moved to the right of its posltion in flgure 4. Film web 15 is stlll held flrmly between film clamp/ :
cutter ~aws 60 and 62 and the turntable fllm clamp 102 is ln clamped posltion with lts rubber edge 104 holding the film web. The trailing edge 144 of the fllm web is then wiped down by brush 16 ~o that it adhers to the wrapped package.
The film brake mechanism, as best seen in Fig~
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ure 7, comprises rubber wheels 110 which are held against the film roll 20 by a tenslon sprlng 150 actlng through shaft 152. The shaft 152 1s supported by and rotates in pillow blocks 154 whlch are secured to vertlcal sup- :~
port 38. Support arms 156 and 157 are.in parallel re-lation to each other and arm 157 rotatably holds shaft 112. The brake 160 is mounted on the lower support arm ~.
156 and supports shaft 112. The upper support arm 157 . .
lles between the two rubber wheels 110. Thus the rubber wheels 110 are always held against the rotating film roll 20 by spring 150 and brake 160 serves to transfer braklng torque through shaft 112 to rubber wheels 110 ln order to stretch the fllm web 15 as lt ls being drawn Orr by the turntable rotatlon. The fllm roll 20 rotates .~ . .
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1o6438o on rlgld sha~t 162 whlch is supported by horizontal sup-port plate 164. The brake 160 can be selectlvely regu-lated to place varying braking forces on shaft 112.
Thus varylng types of fllm can be used ln the apparatus allowing varlance of the fllm tension at the tlme Or severlng by settlng a control to change the braklng force to the deslred tension needed when the film ls severed. Thls varylng tension facllitates the cutting and clamping of the traillng edge of the film.
An alternate embodlment to the invention is shown in Figure 8 whereln a splral wrapping embodiment is shown comprislng a cradle 170 which slides along vertical rails 172 on wheels 174. The vertical ralls 172 are se-cured to the interior sldes o~ the vertical supports 36 and 38. The cradle 170 is driven by motor 176 through gear reduction box 178. The motor causes shaft 180 to rotate, consequently rotating chain sprockets 182 and chain 184. The upward travel of the cradle 170 is limi-ted by upper limit switch 186 while the downward travel of the cradle 170 ls limlted by lower limit swltch 188.
The limit switch cut-off tab 190 is attached to the cradle 170.
In operation ln the splral conflguratlon the palletized load ls placed on the turntable and any de-slred number of rotatlons ls performed wlth the cradle - ' :
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layers of ~llm ls dlspensed onto the load to fasten the rilm to the load. The cradle 170 then travels along the ralls 172 as the turntable contlnues to rotate.
The film ls contlnuously pulled off the film roll so that the fllm is now being placed ln overlapping bands about the load as previously dlscussed on page 10.
An alternate sequence ls avallable where, as the cradle contlnues to travel, the limit switch located on the opposite end from which the wrapping commenced is reached. At thls polnt any desired number of end wrap-plngs may be per~ormed before final cutting takes place.
The clamping/cutting ~aws operate in the same manner as they operate in the preferred embodiment. Since the height of the clamping/cutting ~aws 60 and 62 is greater than the maximum distance of travel to the spiral cradle, then the ~aws will perform their cutting functlon regard-less of the final posltlon Or the film roll in the cradle.
While pre~rred embodiments of the invention ~ ha~e been disclosed, it is understood that the inventio~
i~ is not limited to such embodiments since it may be oth-erwise embodled ln the scope of the appended claims.
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Automatic unitization of loads is currently being accomplished by various types of machines. Specific examples of such machines include strapping and string-tying equipment;
automatic taping machines; palletizers that glue the products together by automatically dispensing hot melt between the units as they are being palletized; automatic shrink film placing units that work in conjunction with shrink tunnels: and auto-matic dual roll push through types stretch film wrappers.
The currently used automatic stretch film placing units stretch the entire web of film at the same time to force it around the load and heat seal the ends of the film together. `
This apparatus has the disadvantage of requiring enormous forces . .
to stretch the film. In addition, the apparatus pulls the film across the corners of the load which may cause rupturing of the , film or deformation of the load. Most importantly, the process requires a critically important seal to reliably secure the load during shipment. If the heat sealing jaws of the apparatus do not provide a perfectly uniform pressure and temperature ,, along their entire length then the film seal will not be par-ticularly strong. Thus the seal will be overheated in some '' areas which will melt the film thin, or crystallize it to a '~ state of brittleness. Alternatively if the seal i9 underheated in some areas deterioration or unwrapping may occur under the ! 30 tension of shipment.
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~06~380 The present invention provides a process of making a unitary package from a load comprising a plurality of units com-prising the steps of placing successive loads on a conveying device; transporting one of the loads to a wrapping apparatus;
holding a leading edge of a stretchable elastic material in a clamp assembly positioned between the forward and trailing corners of the load in a fixed position adjacent to the load;
placing the stretchable material under tension to cause the material to be stretched while rotating the load and the clamp assembly to form an overwrap around the first load and clamp assembly to form a film wrap of at least one layer of stretched film material; releasing the leading edge of stretchable elastic material from the clamp assembly and retracting the clamp : assembly from the film wrap away from the load after the first ~ revolution of the load so that the clamp assembly is pulled out : of the film wrap and the stretched film assumes the former .
position of the clamp assembly to cover the area vacated by the clamp assembly; severing the stretched film material from the - wrapping apparatus to form a leading edge and a following edge of the wrapped load; and simultaneously clamping the leading edge with clamp assembly in a position to begin wrapping of the follow-ing load. .
The present invention further provides an automatic wrapping machine comprising a film support means adapted to dis-pense a roll of film, a turntable adapted to hold a load posi-tioned adjacent to thè film support means, means to rotate the turntable, brake means adapted to place tension on a film web of stretchable material, a clamp means mounted on the turntable adajcen' to the load to hold the film while the turntable with : 30 associated load rotates allowing film to wrap around the load and ~ - 2 -,, ~ .
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the clamp means, the clamp means including release means for releasing the clamp from the film web wrap after completion of at least one revolution of the turntable, a second clamp means mounted above the film web to hold the upper edge of the film means to move the first and second clamp means, the first and second clamp means being moveably mounted so that upon re-traction the turntable clamp means recedes from the film over-wrap below the bottom level of the edge of the film web over-wrap and the upper clamp means raises from the film web overwrap above the top level of the edge of the film web overwrap, a film cutting and clamping means positioned adjacent to the turntable, the film cutting and clamping means having means to cut the film web after the load is wrapped, clamp the free end ~-of the film in a secured position and position the film to be held by the turntable clamp means for the wrapping of the next load.
Preferably, the placing of the film web around the load in multiple layers requires considerably smaller forces to be used in order to obtain the film elongation as is required.
As the load is rotated on a turntable, the application of the film to the load mitigates the sliding or abrading of the film as conventionally occurs. No seals are required when "tacky"
film is utilized, as this type of film normally will have enough cling to bond to itself. In those instances where greater , fastening is required, a simple tack seal bonds the trailing edge of the film to the layers already disposed about the load.
As with the other types of machines the tack seal is completely automatic, which is a necessity in modern plants.
Preferably, the unitizing forces are spread over the product so that these forces are not concentrated at specific - 2a -10643~0;
points which often tends to deform the product. The conven-tional solution of this problem is for padding to be placed beneath the straps. This placement is invariably performed by hand and thus defeats the automatic feature of the operation.
The prior art also discloses the glueing of bags or boxes in order to unitize multiple products into a single load.
The glueing is frequently objectionable to the customers who must pull it apart and does not work particularly well when the product is column stacked.
As the film-holding clamp means of the present machine are wrapped and removed prior to final revolution, the clamp means can be positioned off the side of the conveyor, thereby eliminating the possibility of the pallet load hitting the clamp means.
U.S. Patent No. 3,867,806 discloses a process for making a unitary package in which a load comprising a plurality of units is formed by wrapping a band formed of plural layers ; of a stretched material around the units. This patent requires the holding of the film's leading edge against the vertical surface of the package load by either manual or other non-disclosed fastener means. In the preferred embodiment of the present invention clamps are located on the turntable and a top platen and serve to hold the leading edge of the film against the vertical side of the load to be wrapped. After the first layer of film is wrapped around the load and clamps, the clamps located on the platen and turntable are placed in retracted positions 50 that the load can be conveyed without interference from the clamps.
Upon completion of the fastening steps disclosed in United States Patent 3,867,806, the operator must sever the ' ' -.
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overwrapped package from the film dispenser by employing a drop-knife cutter means which is mounted adjacent the pallet support means. In the preferred embodiment of the present in-vention, film clamp/cutter jaws are used which serve to hold the film in a vertical position while a toothed film cutting bar pierces the entire vertical length of the film at the same instant~ In both cases, the elongation of the film is due to the tension imparted thereon by a tension brake acting on the dispensing roll. Prior to separation the amount of elongation is uniform along the vertical length of the package. In the prior art mode of cutting the film by a sIiding cutting knife, the tension is released and consequently the elongation de-creases as the cutting blade passes through the film. Thus the amount of elongation at the top of the film through which the blade has passed will be less than the elongation present at the bottom of the film, where the blade has yet to pass. This lack of uniformity can lead to the load having a non-uniform stretched film. Consequently a less functional wrap is produced which in addition is less aesthetically appealinq. Such appearance is critical in clear plastic wrapped packagP~. This is so in spite of the fact that the cutting operation is performed subsequent to the sealing operation. Conver~ely, the preferred embodiment of the present invention cuts the entire length of the film at one time, thereby keeping the amount of tension and percent of elongation constant and uniform along the length of the film.
` The uniformity of tension provides a more functional and aesthetically pleasing package. The effect of a onetime total - length cut is further enhanced when a tacky film is employed.
This particular type of film does not require any additional sealing means other than the wipe operation of a brush which ~- _ 4 _ .,~
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1064380 ! ~
secures the trailing edge to the vertical side of the package.
U.S. Patent No. 3,514,920 discloses an apparatus for overwrapping a package by means of a heat shrink film shrunk around a load to provide a unitary package. In that patent the heat-shrinkable plastic film used as an overwrap for the package has a substantially rectangular configuration and has a leading edge portion fastened against the cartons. It will be noted that this apparatus specifically requires the operator,to attach , the leading edge of the plastic film to the cartons. The pre-ferred embodiment of the present invention eliminates this manual operation. In addition to holding the leading edge of the film against the load, after the next load is in position, the clamp means grab and hold the new leading edge of the film in order to facilitate the package of the pallet and associated ~ -' load.
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The use and excessive cost of heat tunnels may be ',~ eliminated since the film web used is stretchable and conse-'~'' quently no heat is required to secure the package.
', United States Patent No. 3,793,798 discloses a shrink `^, 20 palletized process and apparatus. That particular package and ~' process also specifically contemplates the manual withdrawing of , .~, the leading edge of the film and holding that ~eading edge against the package.
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,j An additional advantage of the preferred embodiment of ' ~'I the present invention is the use of the upper platen clamp in ,~ conjunction with lower conveyor located clamp. The utilization ~; of the two clamps allows the film to be held firmly against the ~' '''' ', load at two points. This allows the package to be wrapped uni-formly with equal film tension and elongation along the entire length of the vertical sides of the load.
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~06438~) In previously developed stretchfilm wrapping machines, an edge of the film is either tacked or sealed to the previously wrapped film layers prior to the time of film cutting or separa-tion. This is required because it is necessary to maintain the backward tensio~ and consequently the elongation of the film prior to separation in order for a tight seal to be produced.
After the seal is formed, the film is cut. This leaves a por-tion of the film, i.e. between the seal and the trailing edge, as wasted film. This waste of film can now be avoided by cut-ting the film and subsequently wiping the film against the ver-tical side of the load thereby utilizing the entire film length in a functional capacity.
Other wrapping patents of general interest are Nos.
3,795,086 and 3,589,102. Patents which disclose the spiral wrap--ping of articles and are of interest are 2,575,467; 3,003,297;
3,788,199 and 3,863,425.
When the preferred embodiment is in use, a roll of clear stretchable film is held on a vertically arranged dispen-sing means. Film holding clamps are located upon an upper platen and along one edge of the rotatable load supporting turn-table. At rest, the platen and turntable film clamps are open, the platen is in its "up" position and the cutter clamp jaws engage the film. A load comprising a pallet and package units thereon is conveyed onto the turntable and stopped in the proper position when sensed by a photo-electric cell. Subsequently, the top platen is lowered to stabilize the load and the platen and turntable clamps close to clamp the film. These clamps are ;;designed to hold the film securely against the starting forces on the film and to be able to retract without tearing the film.
In normal operation, the clamps will be retracted after approxi-mately 1 1/4 turns of the turntable in order to allow the high-.
~ - 6 -est level of resultant tension on the load. The platen and turntable film clamps are retracted after 1 1/4 turns to allow subsequent layers to be wrapped directly against the load. The retraction of the clamps, prior to the final wrap layers, allows the film holding clamps to be placed on the side of the conveyor, free from damage by passing pallets. Additionally, the clamps are located at the mid-point of a side of the load in order to allow for maximum "forgiveness" in pallet alignment and register with respect to the leading edge of the film.
The cutter clamp jaws retract to their open position and the turntable rotates the load, which causes the film to be wrapped around the load. A film brake imparts a desired re-striction on the film roll to elongate the film and stretch it around the load. When the desired number of film layers are wrapped on the load, the turntable comes to a stop in its rest position. Additional cutting reliability may be achieved by .~.
automatically reducing or increasing tension to a given level in the last quarter turn to compensate for the type of film being -used.
A "U" shaped film clamping jaw is used to pull the ., film web into its cutting position for engagement with the blade holding film cutter/clamping jaw. As the two film cutter/clamp-; ing jaws close, a toothed vertical blade which extends beyond the edge of the jaws punctures the film as one of the horns of the "U" clamps the film against a rubber pad carried on the cutter/clamping jaw. Consequently, this clamping action holds the leading edge of the film in position for the wrapping of the succeeding load. Thus it can be seen that this system is ex-tremely versatile and reliable because it does not re-quire a precise alignment of blades; and is relatively independent of load size, configuration, rigidity or place-; 7 ~
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10~'~38() ment. As prevlously mentloned thls lnvention contemplatesthe use Or no electrical heating parts. I~ the cuttlng bar merely perforates the rllm and does not completely cut the film web, the movement of the existing load will tear the film apart between the perrorations. The film will then be wiped down rlat against the ~inished package by a ver-tically held brush. It will be appreciated that in most cases, the rilm will have sufricient tackiness so as not to require any further bonding. However, if necessary, a heat sealing operation can be added to the apparatus on the exit conveyor.
In an alternate embodiment, the apparatus is provided with a movable roll carriage in order to expand the machine's capabllitles to include spiral wrapping of very tall loads or random loads of varylng height. If such ls the case, the rllm web ls usually much narrower and there~ore, requires smaller forces to stretch it.
These smaller ~orces may ellminate the need ror the top platen for low production where the turntable rotation speed does not require a top platen ~or stabillty. The spiral wrap apparatus is nearly identical to the full web.
The ~ilm starting requlres only a bottom clamp, lr the splral ls to start and stop at the bottom! Conversely, lt requlres only a top clamp 1~ the film ls started and stopped at the top. The ldentical clamping/cutting mechan-,:
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iO64380 ism described ls also used for the splral conflguratlon and the clamping/cutting bar need not be any longer than ?
the web width of the film in order to perform its func-tion properly.
While the start and flnlsh of the splral opera-tion functions the same as the full web, the wrapplng process lends ltself to great versatility. If the mach-lne is to start and stop at the bottom of the machine, after the initial revolution of the turntable, the fllm roll is raised to spiral the film onto the load. Whlle ' ' at the top or bottom, any number of predetermlned wrap layers can be dispensed to hold and secure the produc~. ¦
The rate at which the film is raised and lowered deter~
mlnes the amount of fllm that wlll be dispensed. -The above mentioned purposes are more readily apparent when read in con~unctlon with the following de- `-'' ' ' talled description of embodiments of the present ln-vention.
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', BRIEF DESCRIPTION OF THE DRAWINGS
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Flgure 1 ls a perspective view Or the automatic wrapplng apparatus, outgoing pallet wlth wrapped load lo-cated thereon, and associated rotatable conveyor;
,, Figure 2 is a,top plan view, wlth top platen removed, of the wrapping apparatus with the pallet and ~, . .~, .
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10643~o load located on the turntable whlch has been rotated through 130 Or the first revolution of the wrap cycle;
Figure 3 is a top plan view, wlth top platen removed, of the wrapping apparatus wlth pallet and load located on the rotatable turntable, at the completlon of the wrap cycle:
Figure 4 is a top plan view of the film clamp/
cutter jaws showing the ~ilm location ~ust as the clamps are fully closed;
Figure 5 is a detailed top plan view of the film clamp/cutter Jaws showing the film location during the lmmediately succeeding step of the wrapping cycle as shown in Figure 4, Figure 6 is a perspective view of the turntable film clamps and top platen film clamps in their closed position;
Figure 7 is a perspective view of the film brake mechanism; and Figure 8 is,a perspective view Or the splral wrapping embodiment.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to the drawings and more particularly to Figure 1, there, is.illustrated a wrapped package 10 - , . - , . , . ~ . - ., -. - , ., . . .. -106~3~0 produced through use Or automatic wrappin~ apparat~s e~body-ing the present inventlon. The package 10 comprises a palletlzed load of boxes 11 located upon a conventlonal forklirt pallet 12. The vertically arranged portlon of the load is overwrapped by a band 14 formed of plural layers Or a stretchable sheet of materlal as for example P.V.C. The layers Or the stretchable material are se-cured together by the tackiness o~ the material to form a cumulatively homogenous band of ~ilm. The trailing edge of the film is likewise secured against the layer beneath it by brush 16.
Figure 1 shows the fllm dispenser apparatus 18 and the roll of film 20 ad~acent to rotatable turntable 22 which supports the load during the wrapping operation.
A first conveyor means 24 carries the palletized load ~. .
to the rotatable turntable 22. A second conveyor means 28 carries the wrapped palletized load O~r the rotatable . , .
turntable 22. A top platen 30 serves to stabllize the load during the wrapplng cycle. The top platen 30 is ~O ralsed or lowered by actuating air cylinder 32 which al-lows the platen to move up or down by slldlng along vertical slide bars 34 which are secured to the apparatus' vertical supports 36, 38. The air cylinder 32 is suppor-ted by bracket 101 which is ln turn supported by vertical support post 100. The top plater~ 30 1B held 1" relatlve `''; ' ' ,, .
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-` 10~31~0 suspended posltlon by a horizontal platen support arm 40 which is ln turn secured to the platen ca~riage 42.
The platen carrlage 42 slides along vertlcal sllde bars 34 on roller bearings (not shown).
The lower surface of the platen 30 ls composed Or a resilient materlal 56 so that when the platen ls lowered the load is not crushed by the platen's welght.
A set of platen film clamps 44 are pivotally secured to the rear vertical wall of the platen 30 as best seen in rigure 6. The rotary air cylinders 50 activate the platen film holding clamps 44 so that they spread apart.
Air lines 54 serve to actiYate the cylinders and are in communication with a source of pressure which is not shown.
An air sllp ring 88 allows the top platen 30 and its attached clamps 44 to rotate along with the load and still maintain the clamps in a closed or open posi- -tlon as desired. The coiled air line 90 runs along the platen support arm 40 to the air slip ring 88 which is --connected through lines 54 to the air cylinders 50 to film clamps 44. The use of the air slip ring allows the platen and clamps to be rotated while still main-taining the clamps in contact with the air supply. Rub-ber edges 52 secured to the clamps hold the fllm in place between the film clamps when closed.
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10~;~3~0 A set of fllm clamping/cuttlng ~aws 60 ana 62 ror clamping and cutting the film at the end of the wrap are held in vertical position by horizontal swing arms 66 and 64 respectively. The ~aws 60 and 62 are secured to the -horizontal swinging arms 66 and 64 by frontal holding bars 68. Air cylinders 70 are secured to the apparatus vertical supports 36 and 38 and serve to rotate the hori-zontal swinging arms 64 and 66 about vertical shaft 72 and 74, respectively by acting on cross support 80. The 1~ vertical shafts 72 and 74 are secured to brackets 76 which are in turn secured to apparatus vertical supports 36 and 38. The air cylinders 70 rotate the horizontal swinging arms 64 and 66 by acting upon a cross support 80 by means o~ sliding piston rod 82. Thus the horizontal arms ro-tate around the vertical shafts.
Electric photo¢ell 86 senses when the front of the load and pallet are in position and serves to stop the conveyor drive motor 92 to place the load and pallet in proper wrapp1ng position.
An electric drive motor 92 and connected gear reducer 94 drives the turntable rollers 96, which allows the palletized load to be stopped ln the proper position, and later to be moved when wrapped.
Turntable fllm clamps 102 are mounted on the slde vertical ed8e of the turntable, as beet seen ln Fig-~0643B0 ure 6. The pair Or clamps hinge at thelr pivot point and are activated by rotary alr cylinders 106. Rubber edges 104 serve to hold the film when the turntable clamps 102 are in their operative or closed position. It should be noted that when turntable clamps 102 are opened to re-lease the film the two Jaw segments each pivot open 90 so that the clamp ~aws are beneath the level of the turn-table.
Similarly when the platen clamps 44 are in open l~ position, the two ~aw segments each pivot 90 so that the clamp ~aws are above the level of the platen. The clamps - hold1ng the film are retracted after the film has been secured to the load by wrapping more than one revolution, so that the clamps do not interfere with the remainder of the wrapping process.
Figure 2 is a top view of the machine after 130 rotation of the first revolution of the wrap cycle. As is shown, the turntable clamp 102 holds the leading edge of the film 15 between rubber edges 104 as turntable 22 ~0 rotates to pull film ofr the film roll 20.
The film is placed under tension so that it stretches as it is being wrapped around the load. Rubber friction rollers 110 mounted on a rotatable shaft 112 en-gage the surface of the film roll to restrict the film ae it i9 bein8 unwounù. A brake 160 engagee the rotat-~0~; ~380 able shaft to llmlt the rotatlon of the shaft as the rol-lers are drlven by the rotatlng surface of the fllm roll thus allowing the deslred degree of tension to be applied to the film.
Figure 3 is a top vlew of the machine at the com-pletion of the wrap cycle. The left fllm clamp/cutter ~aw 62 is shown ln mid-stroke. Turntable film clamps 102 are open at thls point ln the cycle.
Figure 4 is a detailed top vlew of the film clamp/cutter ~aws 60 and 62 showing the film location ~ust as the clamps are fully closed. The left film clamp/cut- ~ -: . .
- ter J aw 62 comprises a support arm 68, a blade support bar : .- .
120 secured to the support arm, a toothed film cutting blade 122, a resillent film clamping pad 124 and a pad support bar 126. The cutting edge of the toothed film cutting blade extends beyond the forward edge Or the blade support bar 120. The right rilm clamp/cutter ~aw 60 is . . .
made up of a film web pusher bar 130, a clamp bar 132 -which is positloned across from bar 130 so as to create an open space 134 between them and a "U" shaped configura-tion. The fllm brush 16 is also secured to the right film clamp/cutter ~ aw 60 on arm 68 at the front-most por-tion of support bar 66. The operative edge 140 of the film web pusher bar 130 is arcuately shaped so a~ not to tear the film. The operative edge 142 of the clamp bar .
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L3~0 132 is rlat so as to engage and hold securely the film 15 against the resllient clamplng pad 124.
In operatlon, it can be seen that the entire width of the film web is easily and reliably clamped and cut in one single operation. The cutting and clamplng operation allow the film tension to be altered prior to the film being actually cut. With the film 15 drawn over the right fllm clamp/cutter ~aw 60 in the positlon shown ln Figure 3, the left ~ilm clamp/cutter ~aw 62 en-b gages it to clamp the film web between clamp ~aw 132 and resllient pad 124. As the resilient pad 124 is compres-sed the cutting edge of the toothed film cutting bar 122 punctures and cuts the film as it forces it apart in the space 134. Motion of the wrapped load on the turntable conveyor also can apply tension to the film so that it will be severed by the cutting bar 122. The film is held between the film clamp bar 132 and the resilient pad 124 whlch now becomes the leading edge of the film for the next succeeding load and pallet.
Severed film portion 144 becomes the trailing edge of the load belng wrapped. As previously mentioned, the ; turntable film clamps 102 and top platen clamps 44 are in the open positlon at this time in the cycle. The position of package units C, D and E is the same as in Figure 3.
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Flgure 5 ls the same view as Figure 4 durlng the following phase of the wrapping cycle, with the load 10 moving off of the rotatable turntable 22. Package .
unit D has moved to the right of its posltion in flgure 4. Film web 15 is stlll held flrmly between film clamp/ :
cutter ~aws 60 and 62 and the turntable fllm clamp 102 is ln clamped posltion with lts rubber edge 104 holding the film web. The trailing edge 144 of the fllm web is then wiped down by brush 16 ~o that it adhers to the wrapped package.
The film brake mechanism, as best seen in Fig~
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ure 7, comprises rubber wheels 110 which are held against the film roll 20 by a tenslon sprlng 150 actlng through shaft 152. The shaft 152 1s supported by and rotates in pillow blocks 154 whlch are secured to vertlcal sup- :~
port 38. Support arms 156 and 157 are.in parallel re-lation to each other and arm 157 rotatably holds shaft 112. The brake 160 is mounted on the lower support arm ~.
156 and supports shaft 112. The upper support arm 157 . .
lles between the two rubber wheels 110. Thus the rubber wheels 110 are always held against the rotating film roll 20 by spring 150 and brake 160 serves to transfer braklng torque through shaft 112 to rubber wheels 110 ln order to stretch the fllm web 15 as lt ls being drawn Orr by the turntable rotatlon. The fllm roll 20 rotates .~ . .
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1o6438o on rlgld sha~t 162 whlch is supported by horizontal sup-port plate 164. The brake 160 can be selectlvely regu-lated to place varying braking forces on shaft 112.
Thus varylng types of fllm can be used ln the apparatus allowing varlance of the fllm tension at the tlme Or severlng by settlng a control to change the braklng force to the deslred tension needed when the film ls severed. Thls varylng tension facllitates the cutting and clamping of the traillng edge of the film.
An alternate embodlment to the invention is shown in Figure 8 whereln a splral wrapping embodiment is shown comprislng a cradle 170 which slides along vertical rails 172 on wheels 174. The vertical ralls 172 are se-cured to the interior sldes o~ the vertical supports 36 and 38. The cradle 170 is driven by motor 176 through gear reduction box 178. The motor causes shaft 180 to rotate, consequently rotating chain sprockets 182 and chain 184. The upward travel of the cradle 170 is limi-ted by upper limit switch 186 while the downward travel of the cradle 170 ls limlted by lower limit swltch 188.
The limit switch cut-off tab 190 is attached to the cradle 170.
In operation ln the splral conflguratlon the palletized load ls placed on the turntable and any de-slred number of rotatlons ls performed wlth the cradle - ' :
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layers of ~llm ls dlspensed onto the load to fasten the rilm to the load. The cradle 170 then travels along the ralls 172 as the turntable contlnues to rotate.
The film ls contlnuously pulled off the film roll so that the fllm is now being placed ln overlapping bands about the load as previously dlscussed on page 10.
An alternate sequence ls avallable where, as the cradle contlnues to travel, the limit switch located on the opposite end from which the wrapping commenced is reached. At thls polnt any desired number of end wrap-plngs may be per~ormed before final cutting takes place.
The clamping/cutting ~aws operate in the same manner as they operate in the preferred embodiment. Since the height of the clamping/cutting ~aws 60 and 62 is greater than the maximum distance of travel to the spiral cradle, then the ~aws will perform their cutting functlon regard-less of the final posltlon Or the film roll in the cradle.
While pre~rred embodiments of the invention ~ ha~e been disclosed, it is understood that the inventio~
i~ is not limited to such embodiments since it may be oth-erwise embodled ln the scope of the appended claims.
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Claims (8)
1. A process of making a unitary package from a load comprising a plurality of units comprising the steps of:
placing successive loads on a conveying device;
transporting one of said loads to a wrapping apparatus;
holding a leading edge of a stretchable elastic material in a clamp assembly positioned between the forward and trailing corners of said load in a fixed position adjacent to said load;
placing said stretchable material under tension to cause said material to be stretched while rotating said load and said clamp assembly to form an overwrap around said first load and clamp assembly to form a film wrap of at least one layer of stretched film material;
releasing the leading edge of stretchable elastic material from said clamp assembly and retracting said clamp assembly from said film wrap away from said load after the first revolution of the load so that the clamp assembly is pulled out of the film wrap and the stretched film assumes the former position of the clamp assembly to cover the area vacated by the clamp assembly;
severing said stretched film material from said wrap-ping apparatus to form a leading edge and a following edge of said wrapped load; and simultaneously clamping the leading edge with clamp assembly in a position to begin wrapping of the following load.
placing successive loads on a conveying device;
transporting one of said loads to a wrapping apparatus;
holding a leading edge of a stretchable elastic material in a clamp assembly positioned between the forward and trailing corners of said load in a fixed position adjacent to said load;
placing said stretchable material under tension to cause said material to be stretched while rotating said load and said clamp assembly to form an overwrap around said first load and clamp assembly to form a film wrap of at least one layer of stretched film material;
releasing the leading edge of stretchable elastic material from said clamp assembly and retracting said clamp assembly from said film wrap away from said load after the first revolution of the load so that the clamp assembly is pulled out of the film wrap and the stretched film assumes the former position of the clamp assembly to cover the area vacated by the clamp assembly;
severing said stretched film material from said wrap-ping apparatus to form a leading edge and a following edge of said wrapped load; and simultaneously clamping the leading edge with clamp assembly in a position to begin wrapping of the following load.
2. A process of making a unitary package as claimed in claim 1, wherein said clamp assembly is retracted by rota-ting it away from said load.
3. The process of claim 1 or 2, including the step of securing the severed following edge of said wrapped load film to an underlying layer of film.
4. An automatic wrapping machine comprising a film support means adapted to dispense a roll of film, a turntable adapted to hold a load positioned adjacent to said film support means, means to rotate said turntable, brake means adapted to place tension on a film web of stretchable material, a clamp means mounted on said turntable adjacent to said load to hold said film while said turntable with associated load rotates allowing film to wrap around said load and said clamp means, said clamp means including release means for releasing said clamp from said film web wrap after completion of at least one revolution of said turntable, a second clamp means mounted above said film web to hold the upper edge of said film means to move said first and second clamp means, said first and second clamp means being moveably mounted so that upon retraction the turn-table clamp means recedes from the film overwrap below the bottom level of the edge of the film web overwrap and the upper clamp means raises from the film web overwrap above the top level of the edge of the film web overwrap, a film cutting and clamp-ing means positioned adjacent to said turntable, said film cutting and clamping means having means to cut the film web after the load is wrapped, clamp the free end of the film in a secured position and position the film to be held by the turn-table clamp means for the wrapping of the next load.
5. An automatic wrapping machine comprising a film support means adapted to dispense a roll of film, a turntable adapted to hold a load positioned adjacent to said film support means, means to rotate said turntable, brake means adapted to place tension on a film web of stretchable material, a clamp means mounted on said turntable adjacent to said load to hold said film while said turntable with associated load rotates allowing film to wrap around said load and said clamp means, said clamp means including release means for releasing said clamp from said film wrap after completion of at least one revolution of said turntable, a platen movably mounted to said film roll support means, said platen being formed with a resilient lower surface adapted to engage the top of the load and hold said load in position on said turntable, a rotatable clamp means mounted on said platen, said rotatable clamp means being adapted to hold said film while said turntable with associated load rotates allowing film to wrap around said load and said rotatable clamp means, said rotatable clamp means in-cluding means to retract it from said film wrap after com-pletion of at least one revolution of said turntable, a film cutting and clamping means positioned adjacent to said turn-table, said film cutting and clamping means having means to cut the film web after the load is wrapped, clamp the free end of the film in a secured position and position the film to be held by the turntable clamp and rotatable clamp for the wrapping of the next load.
6. Apparatus as claimed in claim 5, wherein said rotatable clamp means comprise a pair of opposing clamp members which hinge at a pivot point and are activated by cylinder means, each of said clamp members having resilient edges serving to hold the film when the clamp members are in their closed position.
7. Apparatus as claimed in claim 5 or 6, including brush means positioned adjacent to said load, said brush means engaging the film web wrapped around said load to secure it to the underlying film layer.
8. Apparatus as claimed in claim 5 or 6, wherein said film is polyvinylchloride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA319,466A CA1064381A (en) | 1976-05-28 | 1979-01-11 | Automatic wrapping apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/691,019 US4077179A (en) | 1974-06-12 | 1976-05-28 | Automatic wrapping apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1064380A true CA1064380A (en) | 1979-10-16 |
Family
ID=24774852
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA279,024A Expired CA1064380A (en) | 1976-05-28 | 1977-05-24 | Automatic wrapping apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5311690A (en) |
| AU (1) | AU511642B2 (en) |
| CA (1) | CA1064380A (en) |
| DE (1) | DE2724100C2 (en) |
| GB (1) | GB1581674A (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2717647C3 (en) * | 1977-04-21 | 1981-07-16 | C. Keller GmbH u. Co KG, 4530 Ibbenbüren | Device for wrapping a stack in a web of plastic film |
| FR2416167A1 (en) * | 1978-02-07 | 1979-08-31 | Thimon Sa Thimon Ets | METHOD AND DEVICE FOR APPLYING AND MAINTAINING A STRIP OF FILM STRIP ON A LOAD |
| US4232501A (en) * | 1978-05-01 | 1980-11-11 | Lantech Inc. | Economy automatic wrapping apparatus |
| DE2836590C2 (en) * | 1978-08-21 | 1980-07-10 | C. Keller Gmbh U. Co Kg, 4530 Ibbenbueren | Welding and cutting device for welding and cutting a plastic film |
| JPS55143206A (en) * | 1979-04-26 | 1980-11-08 | Nippon Carbide Kogyo Kk | Film stretch packing apparatus |
| DE3106845A1 (en) * | 1980-02-27 | 1982-01-14 | Joseph R. 40223 Louisville Ky. Lancaster | "METHOD FOR PRODUCING A PACKING UNIT FROM MULTIPLE STACKED PARTS BY WRAPPING THROUGH A STRETCH FILM SHEET" |
| JPS5742987U (en) * | 1980-08-25 | 1982-03-09 | ||
| NZ198286A (en) * | 1980-10-27 | 1985-07-12 | Infra Pak Dallas Inc | Pre-stretching film web from feed stock and wrapping palletised load |
| DE3105924C1 (en) * | 1981-02-18 | 1983-05-19 | Hans Hugo 4020 Mettmann Büttner | Machine for mounting hood-shaped film covers on items to be packaged |
| IT1195385B (en) * | 1983-01-25 | 1988-10-19 | Robopac Srl | PROCEDURE AND DEVICE FOR WRAPPING CONTAINERS AND SIMILAR |
| FI831375L (en) * | 1983-04-21 | 1984-10-22 | Haloila M Oy Ab | FOERPACKNINGSMASKIN. |
| DE3440416A1 (en) * | 1984-11-06 | 1986-05-07 | B. Hagemann & Co, 4430 Steinfurt | Method and apparatus for mounting a section of a piece of film on the end face of a conveyed container |
| GB8607144D0 (en) * | 1986-03-22 | 1986-04-30 | Vennall G | Ideal cover wrapping machine |
| ES2000561A6 (en) * | 1986-07-24 | 1988-03-01 | Inpropack S L | Pallet wrapping apparatus |
| GB2204850A (en) * | 1987-05-16 | 1988-11-23 | Gerald Vennall | Bale wrapping apparatus |
| NO171628C (en) * | 1987-10-12 | 1993-04-14 | Pusnes As | ROTARY HEAD |
| DE3912852C2 (en) * | 1988-04-20 | 1996-02-29 | Beumer Maschf Bernhard | Method and device for forming loading units using a web-shaped stretch film |
| SE9003250L (en) * | 1990-10-11 | 1992-04-12 | Anders Billberg Ab | wrapping |
| US5408808A (en) * | 1992-08-12 | 1995-04-25 | Oji Seitai Kaisha, Ltd. | Automatic full-web stretch-wrapping apparatus |
| FR2718414B1 (en) * | 1994-04-07 | 1996-05-15 | Newtec Int | Optimized process for overpacking and transporting an overpackaged load. |
| FR2748734B1 (en) | 1996-05-06 | 1998-07-31 | Thimon | OVERPACKING FILM, FILM PRE-STRETCHING DEVICE AND OVERPACKING PROCESS |
| JP6647345B2 (en) | 2018-06-14 | 2020-02-14 | コアレックス信栄株式会社 | Manufacturing method of package |
| CN109383019A (en) * | 2018-10-26 | 2019-02-26 | 景宁众驰自动化科技有限公司 | Power supply adaptor automatic assembling coating assembly line |
| CN113264211B (en) * | 2021-05-11 | 2023-04-14 | 深圳市吉奥科技有限公司 | Mobile phone charger film coating device with positioning function |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1807869A (en) * | 1927-02-19 | 1931-06-02 | American Fork & Hoe Co | Shaft wrapping machine |
| US3867806A (en) * | 1973-04-04 | 1975-02-25 | Lantech Inc | Process of making a stretched-wrapped package |
-
1977
- 1977-05-24 CA CA279,024A patent/CA1064380A/en not_active Expired
- 1977-05-26 AU AU25548/77A patent/AU511642B2/en not_active Expired
- 1977-05-27 GB GB2242577A patent/GB1581674A/en not_active Expired
- 1977-05-27 DE DE19772724100 patent/DE2724100C2/en not_active Expired
- 1977-05-28 JP JP6177277A patent/JPS5311690A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5630246B2 (en) | 1981-07-14 |
| JPS5311690A (en) | 1978-02-02 |
| DE2724100A1 (en) | 1977-12-15 |
| AU2554877A (en) | 1978-12-07 |
| DE2724100C2 (en) | 1983-12-22 |
| GB1581674A (en) | 1980-12-17 |
| AU511642B2 (en) | 1980-08-28 |
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