Method of and apparatus for removing labels

Abstract: A machine (10) for removing tubular plastic labels from bottles (13) to facilitate their re-use and recycling. The machine (10) has a multi-station turret and supply (24) and exit conveyors (80) to sequentially supply labelled bottles (13) in line to the turret and remove delabelled bottles (17) from the turret. The delabelling is accomplished with a cutter (54) which is preferably in the form of a high-pressure jet of water. Ideally, the cutter is adjusted so that it is a differential cutter which will cut a label without cutting or marring a bottle from which a label is being removed. With one embodiment, a water flush mechanism (34) is provided to flush cut labels from their bottles (13) and the turret onto a screen conveyor (36). The flush water passes through the conveyor (36) into a container (38) from which it is pumped for re-use. Removed labels are transported by the screen conveyor (36) to a collection bin (39). With another embodiment, an air blast mechanism (40) is used to strip cut labels from bottles (13) and a vacuum pick (41) up is used to collect stripped labels.

Description: This invention relates to bottle delabellers, and concerns a high-speed automatic delabeller suited for removing tubular plastic labels from bottles and a method of label removal. Plastic labels are enjoying increasing use for labelling beverage and other bottles. Many of these labels are of a wrap-around type, each of which is adhesively secured to its bottle. Plastic labels in the form of tubular sleeves, each of which is slid over the bottle are being used in increasing quantities. Until recently, the major advantage of wrap-around labels has been their low-cost achieved by high-speed labelling machines that have had greater throughput than sleeving machines. With the advent of the machine disclosed in EP-A-0 547 754 (EP Application No. 92310205.7 filed 6.11.92) also referred to as the "Labeller Patent" wrap-around labels no longer enjoy economic advantage over tubular sleeves. Indeed, given that the glue accounts for approximately eight percent of their cost, wrap-around labels are now more expensive. This is especially true if one takes into account the fact that, if there is a labelling malfunction with a glue-on label, both bottle and label are typically thrown away while, with the sleeve labels, the label is removed and another label is applied to the bottle. A major advantage of tubular sleeve labels is that they can be removed from bottles to enable total recycling of both the bottle and the label. Wrap-around labels, on the other hand, make it impractical to fully recycle such things as a labelled plastic bottle because the label cannot be economically separated from the bottle, and the label and bottle are typically made of different materials, namely polyethylene for labels and P.E.T. for the bottles. The Applicants have developed a system and machine for removing labels from bottles as a set of bottles are transferred from a case to, for example, a washer for processing bottles for re-use. While the machine is quite satisfactory for its purpose, there has remained a need for a high-speed effective automatic delabeller for removing labels from used bottles in a bottling plant where they are to be refilled and relabelled as by the machine disclosed in EP-A-0 547 754 (EP Application No. 92310205.7 filed 6.11.92). The need is especially apparent where the bottles to be delabelled are fluted or otherwise specially configured. This need is increasing because the re-use of bottles of both glass and plastic is increasing at significant rates DE-A-2403085 shows a water jet delabelling machine in which the jet is directed tangentially on bottles which would be somewhat ineffective to remove a tubular label. In EP-A-0269743 a machine is shown which uses a plurality of hot air jets to slice a tubular label. The use of hot air would damage plastics bottles such that they would be unreusable, whilst the use of a plurality of jets without relative axial movement of label and jet involves an expensive mechanism. According to the invention there is provided a method of removing a label from an object comprising a) directing a high pressure fluid cutting jet against an outer surface of the label; characterised by b) relatively moving the jet and the object to cut the label from one end to another end; and, c) maintaining the pressure, volume and velocity of the jet fluid at respective values which are high enough to effect cutting of the label while low enough to avoid cutting the object. Further according to the invention there is provided a delabelling machine for removing a label from a work piece, comprising fluid jet cutter means characterised by means arranged to cause relative movement of the cutter means and work piece and means for maintaining pressure, volume and velocity of the jet fluid at respective values which are high enough to effect cutting of the label while low enough to avoid cutting the workpiece, whereby the cutter means is caused to sever the label without marking the workpiece. With an embodiment of a delabelling machine made in accordance with the present invention, a bottle transporter may be provided. The transporter may have a series of spaced delabelling stations which successively receive bottles from a supply conveyor and transport them to a discharge conveyor as the labels are concurrently removed from the bottles. In a preferred embodiment, the bottle transporter is a turret with a plurality of circumferentially spaced label removal stations. EP-A-0 547 754 (EP Application No. 92310205.7 filed 6.11.92) discloses one system suitable for use with a delabeller according to this invention for supplying bottles to a turret in appropriately spaced relationship and then removing bottles from the turret after a work operation has been performed. With a preferred turret, each delabelling station includes a bottle support platform which, in contrast to the machine disclosed in EP-A-0 547 754 (EP Application No. 92310205.7 filed 6.11.92), is vertically fixed. Each delabelling station also has a bottle hold-down which is moved into engagement with a bottle once it has been transferred from the supply conveyor and restrains the bottle on the platform of that station until the bottle reaches a discharge station for discharge onto the exit conveyor. Each delabelling station also includes a cutter. Preferably, the cutter is a differential cutter which cuts the relatively soft plastic of a plastic label top to bottom while not cutting or otherwise marring the bottle being delabelled. Where the label is polyethylene or similar material, the inherent elasticity of the label contracts the label once cut, thus widening the cut and concurrently tending to sever any physical adherence of the label to the bottle. As the turret continues to rotate the bottle with its cut label, they pass through a label-removing mechanism. With one embodiment, the label-removing mechanism has a flushing station where flowing water flushes the cut label from the bottle and onto a label-separating conveyor positioned below the turret. The separating conveyor allows the flush water to pass through to a collection tank positioned below it. Water from the collection tank is pumped back to the flusher for re-use. Separated labels are transported by the separating conveyor to a collection bin. With another embodiment, an air blast separates labels from the bottles. The separated labels may then be forced by pressure differential into a partially evacuated conduit. A preferred differential cutter is a water jet which is traversed vertically from top to bottom of the label, or vice versa, to affect label-cutting action. With careful control of the rate of cutter traverse together with the pressure, volume and velocity of the water emitted by each such jet, the desired differential cutting action is achieved. The labels are effectively and thoroughly cut top to bottom, but the bottle is neither cut nor marred. The novel differential cutters provide one of the outstanding features of the present invention. In one embodiment, a vertically disposed piston and cylinder provide a high-pressure water pump. An air cylinder is coupled to the piston selectively to drive the piston upwardly when a label cut is to be effected. The upward orientation is preferred because any air entrained in supplied water will rise to the top and be expelled prior to or with the water during each cutting cycle. Accordingly, air build-up in the water cylinder is avoided. The output from the water cylinder is directed through high pressure tubing to a nozzle with a horizontally directed output. The preferred embodiment of the cutter is in the form of a novel subcombination of a system embodying this invention. With the preferred cutter, each work station has a cylindrical water tube mounted in a fixed position adjacent the station. The tube is connected to a water supply at its base, and when the tube is filled with water, it functions as a jet-producing piston. A tubular piston rod surrounds the water tube. The rod has an internal fluid chamber, the walls of which slidingly engage the water tube. A fluid cylinder surrounds the piston rod in concentric relationship and an annular piston interposed between the cylinder and the rod effects selective reciprocal motion of the rod. The jet-producing cutter nozzle is fixed to the piston rod near its upper end and is in fluid communication with the piston rod's fluid chamber. When the preferred cutter is in use, the annular piston is driven upwardly to extend the piston rod and elevate the nozzle. Concurrently, water is introduced into the water tube to fill both the tube and the fluid chamber of the piston rod. The direction of piston and rod is then reversed, and concurrently, the water supply is cut off. As the piston descends, the water tube functions as a jet-producing piston as water is driven from the piston rod's fluid chamber through the nozzle to affect a label-cutting action. With either cutter embodiment, water is supplied from from a suitable source such as a factory water line. Water flows from the water line through a check valve into the water cylinder's chamber in the one embodiment and the water tube in the preferred embodiment. With the first embodiment, water is supplied as or after the piston is retracted following a label-cutting cycle. With the preferred embodiment, water is supplied as the nozzle is elevated. With both embodiments, high-pressure water lines are avoided apart from the tubing connecting the water cylinder to the nozzle in the one case and the piston rod in the other. Similarly, the air cylinder does not require pressure other than that normally supplied by a source such as factory air. By adjustment of the air pressure supplied to the cylinder, one is able to control the pressure, volume and velocity of water emitted by the nozzle and thereby effect the desired differential cutting of labels without harm to the bottles. The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a front elevational view in somewhat schematic form showing an embodiment of a bottle delabelling system according to the invention; Figure 2 is a top plan view of the turret of this embodiment, from the plane indicated by the line 2-2 in Figure 3, showing star wheels for transfer of bottles to and from the turret; Figure 3 is an end elevational view of the machine in Figure 1; Figure 4 is an enlarged fragmentary view showing a labelled bottle with the differential knife positioned to commence a cutting operation; Figure 5 is a view corresponding to Figure 4 showing the label and the differential knife after the cutting operation has been concluded; Figure 6 is a partially sectioned elevational view of a preferred cutter assembly; and, Figure 7 is a diagrammatic plan view of an air blast and vacuum system for removing cut labels. Referring to the drawings and Figures 1-3 in particular, a delabelling machine is shown generally at 10. As is best seen in Figure 1, a supply conveyor 12 delivers labelled bottles 13 to a bottle transporter in the form of a turret 14. A discharge conveyor 15 receives delabelled bottles 17 from the turret and transports them downstream for further processing. The turret 14 is supported by an overhead shaft 18. The shaft 18 is connected by structure (not shown) to a frame 20 of a delabelling section shown generally at 22. The structure supporting the shaft 18 on the frame 20 includes a drive for rotating the shaft and with it the supported turret 14. While the supply and exit conveyors 12, 15 are shown schematically here, it should be recognized that the supply and exit mechanism disclosed in EP-A-0 547 754 (EP Application No. 92310205.7 filed 6.11.92) of the Labeller Patent is well suited for delivering labelled bottles to and transferring unlabelled bottles from the turret 14 of the machine 10. A supply star wheel 24 is provided. The supply star wheel 24 transfers labelled bottles 13 from the supplier conveyor 12 to a registered one of twelve work stations 25 on the turret 14. Each of the work stations 25 includes a bottle hold-down 27. The bottle hold-downs 27 are mounted on a rotatable hold-down support 29 which is secured to and rotates with the shaft 18. Each of the hold-downs 27 includes a cylinder 30 or equivalent structure to shift its hold-down 27 between a bottle-retaining position at the left of Figure 1 and a bottle release position at the right in Figure 1. Each of the delabelling stations includes a differential cutter assembly. One embodiment of the cutter assembly is shown at 32 in Figures 1 and 3-5, while the currently preferred form is shown at 32' in Figure 6. With the embodiment of Figure 1, the cutter assemblies are mounted for vertical reciprocal movement between the positions shown in Figures 4 and 5, and also shown to the left and right respectively in Figures 1 and 3. The cutter assemblies 32 or 32', each being part of a delabelling station 25, are mounted on the turret 14 for rotation with it. With the embodiment of Figures 1-5, flushers 34 are provided to water flush cut labels from the bottles. The flush water and cut labels 35 (Figure 1) drop onto a screen conveyor shown schematically at 36 in Figure 3. Flush water passes through the screen conveyor 36 into a collection vat 38. Separated labels are transported by the screen conveyor 36 to a label collection bin 39. Referring to Figure 7, another label-removing mechanism is shown. In Figure 7, the delabelling machine 10' includes air blast mechanisms 40 positioned to blow cut labels loose from their bottles. Once loosened, the labels are forced, by differential air pressure, into a vacuum conduit or evacuated hood 41. The hood 41 is connected to a vacuum source and to a label collection device, neither of which is shown. Referring to Figures 4 and 5, the differential cutter assemblies 32 are shown with some detail. Each cutter assembly includes a housing and frame 42 for supporting the balance of the cutter assembly. Mechanism (not shown) is interposed between the turret and the housing and frame to cause selected vertical reciprocation of the cutter assemblies. A housing 44 for a reciprocal water pump is mounted on the top of the housing and frame 42. The pump housing 44 defines an internal, cylindrical, water chamber 45. A piston rod 46 is provided for reciprocation between a lower position shown in Figure 4 and an upper position shown in Figure 5. This reciprocation is effected by an air cylinder 48 that is operably connected to the piston 46. A water supply conduit 50 is coupled through a check valve 52 to the water chamber 45. At the conclusion of the cutting cycle, water is supplied through the check valve 52 to fill the water chamber 45. A cutting nozzle 54 is connected through high-pressure tubing 55 to the water pump housing 44 for communication with the water pump chamber 45. Another and now preferred cutter assembly 32' is shown in Figure 6. The cutter 32' includes a tubular cylinder 60 which is interposed between upper and lower annular end closures 61, 62. The upper end closure 61 is fixed to the turret 14 so that the cylinder 60 depends from it. The piston has smooth, cylindrical internal walls 64 which define an internal fluid chamber. An annular piston 65 is reciprocally mounted in the cylinder 60 in sliding and sealing engagement with the walls 64. An annular piston rod 67 is carried by the piston 65 for reciprocation with it. The rod projects vertically upwardly through, and in slidable and sealing relationship with, the upper end closure 61. Thus, the piston rod 67 has an upper, external portion 68 extending above and projecting from the upper closure 61. The piston rod 67 includes a throughbore 70 which defines and functions as a water chamber. A nozzle 54 is connected by tubing 55' to the upper portion 68 of the piston rod. The tubing provides fluid communication between the piston rod bore 70 and the nozzle 54. A tubular jet piston 72 is positioned co-axially within the piston rod bore 70. The external walls of the jet piston 72 are in complemental sliding relationship with the walls defining the rod bore 70. A packing 73 surrounds the jet piston 72 and effects a fluid-tight seal between the rod bore 70 and the jet piston 72. A water supply line 50' is connected through a check valve 52' to the lower end closure. Water from the supply line 50' is fed into the jet piston 72 concurrently with the elevation of the piston and rod. Water flows through the jet piston 72 as the piston and rod are rising to maintain the piston rod bore 70 and the nozzle supply tubing 55' in a filled condition. On reversal of the piston to cause it to descend, the check valve 52' prevents water from escaping from the tubular piston 72. Since the tubular piston is filled with water, it acts the same as if it were a solid rod piston forcing water through the nozzle 54 as it descends from its pre-cut position shown in phantom in Figure 6 to the label cut position shown in solid lines. In operation, labelled bottles 13 are transferred by the star wheel 24 from the supplier conveyor 12 to the turret 14. As viewed in Figure 2, the transfer from the star wheel to the turret occurs when an empty station 25 is at the seven o' clock position. The turret rotates in a clockwise direction as viewed in Figure 2. When a labelled bottle arrives at the eight o' clock position, the differential cutter assembly 32 is in the position of Figure 4. Air is delivered to the cylinder 48 via air supply conduits 58. Operation of the air cylinder drives the water piston 46 upwardly causing check valve 52 to close and water to be expelled from the cutting nozzle 54. Because of the upward operation of the water piston 46, any air entrapped in the water chamber 45 will be expelled prior to and perhaps with the water. The check valve 52 assures that the water is expelled through the nozzle and not returned to the supply line 50. Concurrently, with the upward movement of the water piston 46, the entire differential cutting assembly 32 is traversed downwardly from the position shown in Figure 4 to the position shown in Figure 5 to cut the label from top to bottom. This cutting action occurs as a cutter assembly is transferred from the eight o' clock to the ten o' clock position as viewed in Figure 2. Assuming the label to be polyethylene, once it is cut, its inherent resiliency will cause retraction tending to pull the label from the position shown in dotted lines in Figure 5 to the position shown in solid lines. With the now preferred cutter arrangement, air under pressure is introduced below the piston 65 to elevate the piston rod and the nozzle 54 to the position shown in phantom in Figure 6. Concurrently, water is drawn through the check valve 52' to maintain the jet piston 72, the piston rod bore 70, and the nozzle supply tubing 55' in a filled condition. Once the nozzle has reached its upward position, air is exhausted from under the piston 65 and air under pressure is introduced above it. This drives the piston and its connected rod 67 downwardly. As the piston rod descends, water is forced through the nozzle 54 to effect a differential cut. The check valve 52' prevents the escape of water from the jet piston 72 so that the tubular jet piston 72 and the column of water maintained within it function as a solid piston rod to drive water from the piston rod bore 70 through the tubing 55' and thence the nozzle 54. With either the cutter assembly of Figure 4, 5 or 6, the pressure of the cutting water jet is a function of the pressure supplied to the air cylinder which causes water to be expelled through the nozzle 54. To this end, valves shown schematically at 75, 76 (Fig. 4) are provided to adjust the air pressure supplied to the cylinder 48. In the case of the embodiment of Figure 4, an independent adjustment, not shown, is provided to adjust air pressure supplied to the mechanism causing cutter reciprocation. In the case of the embodiment of Figure 6, the speed of cutter traverse and the pressure of the nozzles are interconnected variables with a single adjustment. Thus, with the embodiment of Figure 6, one cannot adjust the speed of cutter traverse without also adjusting the pressure of the cutting jet while in the embodiment of Figure 4 and 5 independent adjustments for these two variables are provided. The flusher 34 of the embodiment of Figures 1-5 is shown at the two o' clock station in Figure 2. Further flushers could be supplied at the twelve, one, three and four o' clock stations if desired. The cut labels are flushed from the bottles and the turret onto the screening conveyor 36. Flush water passes through the screening conveyor 36 into the collection vat 38 while removed labels 35 are transported by the screen conveyor 36 to the label receptacle bin 39. When the delabelled bottle 17 reaches a transfer position shown at five o' clock in Figure 2, an exit star wheel 80 transfers the delabelled bottles 17 onto the exiting conveyor 15 for transport to another location for further processing. With the embodiment of Figure 7, blasts of air are emitted from mechanisms 40 to blow cut labels loose from their respective bottles. Through pressure differential, the loosened labels are then drawn into a vacuum hood 41 and thence, transported off to a collection station.

Claims: A method of removing a tubular plastic label from an object (13) comprising: a) directing a high pressure fluid cutting jet against an outer surface of the label; characterised by b) relatively moving the jet and the object to cut the label in a direction substantially parallel to its longitudinal axis from one end to another end; and, c) maintaining the pressure, volume and velocity of the jet fluid at respective values which are high enough to effect cutting of the label while low enough to avoid cutting the object. A method according to Claim 1 wherein the label is a relatively soft plastic sleeve and the object is a bottle of relatively harder material such as plastic. A method according Claim 1 or 2 wherein the fluid is water. A method according to any one of the preceding claims wherein a fluid driven piston is driven to force fluid through a nozzle to produce the jet. A method according to Claim 4 wherein the pressure, volume and velocity of the jet fluid is adjustable. A method according to Claim 5 wherein the pressure, volume and velocity of the jet is adjusted by adjusting fluid pressure supplied to its associated piston. A method according to any one of the preceding claims further including the step of stripping the cut label (35) from the bottle. A method according to one any of the preceding claims wherein the objects are bottles and further including the steps of: a) sequentially feeding the bottles to a bottle transporter (14) having a plurality of spaced label removal stations (25); b) sequentially positioning the bottles one at a time at the stations; c) moving each positioned bottle through a portion of a path to a discharge station; d) forming a cut in each of the labels extending from top to bottom by impinging fluid jets against the labels as their respective bottles are moving along the portion; and, e) removing the cut labels from the bottles. A method according to Claim 8 wherein the transporter is a turret. A method according to any of Claims 2 to 9 wherein the bottles and their respective jets are relatively moved axially of the bottle to effect each label cut from substantially one end of the label to the other. A method according to Claim 10 wherein the bottles are maintained axially stationary while their respective jets are moved axially from substantially one end of the label to the other to effect a label cut. A method according to any of the preceding claims wherein the cutting of each label allows the inherent resiliency of a cut label to assist in the separating step. A method according to any one of the preceding claims wherein the labels are removed by flushing. A method according to Claim 10 wherein the flushed labels (35) are screen (36) separated from the fluid and the fluid is collected in a tank (38) below the screen. A method according to any of Claims 1 to 12 wherein the removal includes separating a cut label from its object with an air blast mechanism (40) and a vacuum pick up (41). A method according to Claim 4 or any one of Claims 5 to 15 as dependent upon Claim 4 wherein each piston is driven by a fluid cylinder (48, 60) and wherein the pressure, volume and velocity of the jet fluid is adjusted by adjusting air pressure supplied to the cylinder. A delabelling machine (10) for removing a tubular plastic label from a work piece (13), comprising fluid jet cutter means (32,32') characterised by means (48, 60) arranged to cause relative movement of the cutter means and work piece in a direction substantially parallel to the longitudinal axis of the label and means (75, 76) for maintaining pressure, volume and velocity of the jet fluid at respective values which are high enough to effect cutting of the label while low enough to avoid cutting the workpiece, whereby the cutter means is caused to cut the label over its entire length without marking the workpiece. A delabelling machine according to Claim 17 further including a labelling station (25) comprising: a) a work piece support platform (14); b) a work piece hold down (27) adapted to retain a positioned work piece (13) on the platform; and, c) the means (48;60) to cause relative reciprocal motion being arranged to cause relative reciprocal movement of the platform and the mechanism, the cutter being a fluid jet differential cutter (54) capable of severing at least a substantial portion of a sleeve surrounding a work piece without marking the work piece. A delabelling machine according to Claim 18 wherein the differential cutter includes a water jet nozzle (54). A delabelling machine according to Claim 19 wherein a body (44;67) defines a fluid chamber (45;70) in fluid communication with the nozzle, a jet producing piston (46;72) is operatively disposed in the chamber and a fluid actuated cylinder (48;60,65) is operatively connected to the piston for selectively expelling fluid from the chamber. A delabelling machine according to any one of Claims 17 to 20 further comprising: a) a delabelling work piece transporter (29,14) having a spaced set of delabelling stations (25); b) a supply conveyor (24) positioned adjacent the transporter for supplying work pieces (13) in the form of labelled necessarily hollow objects sequentially to a supply location; c) an exit conveyor (80) also positioned adjacent the transporter for removing delabelled objects (17) from the transporter; and, d) a label stripping means (34;40,41) for removing cut labels from such objects. A delabelling machine according to Claim 21 wherein the stripping means is a water flush mechanism (34). A delabelling machine according to Claim 22 further including a separating means (36) for separating stripped labels from flush water. A delabelling machine according to Claim 23 wherein the separating means includes a screen (36) and a vat (39) to collect flush water. A delabelling machine according to any one of Claims 21 to 24 wherein the transporter is a turret. A delabelling machine according to Claim 21 wherein the stripping means includes an air blast mechanism (40). A delabelling machine according to Claim 26 further including a vacuum pick up (41) for collecting separated labels.

Inventors: HESS RICHARD W, LERNER HERSHEY, LIEBHART DANA J, HESS, RICHARD W., LERNER, HERSHEY, LIEBHART, DANA J.
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 1993
Main classification: B08B9
IPC codes: B65B55, B08B9