GB2138387A - Label applying device for applying self-adhesive labels to articles - Google Patents

Abstract

A label applying device for applying self-adhesive labels to articles comprises a pad 58 having a surface 59 to receive the label, the pad being formed with a gap 69 extending around the perimeter of the label receiving surface 59 and an air pressure supply/vacuum source (CA/V, Figure 6) being connectable to the pad to draw vacuum at the gap or create a jet of air at the gap to hold a label on the pad 58 or to propel the label from the pad on to the surface of an article to adhere thereto as required. <IMAGE>

Description

SPECIFICATION Improvements in or relating to label applying devices for applying self-adhesive labels to articles This invention relates to label applying devices for applying self-adhesive labels to articles and is particularly although not exclusively applicable to labels applying devices for labelling apparatus of weigh/price labelling machines in which articles (usually items of food) are delivered by a conveyor to a weigh station where they are weighed and then to a labelling station where a label printed with weight and price computed from the measured weight and other information such as dates, goods description and appropriate bar codes is applied to the article.

This invention provides a label applying device for applying self-adhesive labels to articles comprising a pad having a surface to receive a label, means to draw vacuum at the surface to hold a label on the surface, a slot extending around the surface in a closed path and means to apply air under pressure to the slit to create a jet of air in the form of a skirt to propel a label on the pad on to the surface of an article.

The skirt of air provides a stable propellant for delivering a label on to an article at some distance remote from the pad so that the pad position for delivery of a label does not have to be adjusted to suit the height of the articles to which the labels are to be applied. It is desirable that the contour of the skirt of airfrom the pad is generally similar to that of the label to be applied so that in the case of a rectangular label, the slit in the pad is made in the form of a rectangle.

The following is a description of a specific embodi mentofthe invention, reference being made to the accompanying drawings in which: Figure 1 is an elevation view of a label applying apparatus for use in a weight/price labelling machine; Figure 2 is an end view of the apparatus shown in Figure 1; and Figure 3 is a detailed view of part of the apparatus shown in Figure 1.

Figure 4 is a detailed view of part of the apparatus shown in Figure 3 sectioned as indicated by the line IV-IV in Figure 5; Figure 5 is a sectioned view as indicated by the line V-V in Figure 4; and Figure 6 is a view, looking in the opposite direction to Figure 4, of part of the apparatus shown in Figure 5.

The drawings illustrate a labelling apparatus for a weigh/price labelling machine in which a conveyor system transports articles to be weighed and priced to a weigh station where the weight of each article is measured and the article price computed from the weight and are then delivered to a labelling station where a label printed with the weight and price information computed for that article is applied to the article.

Referring now to the drawings, the label applying apparatus shown comprises an upright base 10 on which the following elements are mounted: i) A device 11 for holding a reel of self-adhesive labels mounted on a backing; ii) An apparatus 12 for printing weigh/price information on the labels on the backing and stripping the labels one by one from the backing; iii) A feed device 13 for drawing the backing through the weigh/price/label stripping apparatus; iv) A device 14 for receiving stripped labels one by one from the backing and applying the labels to the appropriate articles.

Referring now to Figure 1 of the drawings the holder 11 for a reel of label carrying strips comprises a spindle 15 mounted for rotation on the base and carrying a drive pulley 16 connected by a belt drive 17 to the output pulley 18 of a drive motor 19. The spindle 15 carries a large triangular shaped backing plate 20 and a hub assembly 21 to receive a reel of label supply strips. The strip indicated at 22 is fed around a roller 23 disposed below the holder 11. The reel of strip is located on the holder 11 to be drawn off clockwise if the labels are disposed on the outer side of the strip or anti-clock if the labels are disposed on the inner side of the strip (as indicated by the line of strip 22a)so that the labels are disposed on the outer side of the strip as they pass around the drum 23.The strip 22 then passes to a jockey roller 24 mounted on a swing arm 25 pivoted at 26 on the base, one micro-switch 27 is mounted in the upward path of movement of the arm 25 and a second micro-switch 28 is mounted in the downward path of movement to be engaged by a pin 29 on the arm moving in an arcuate slot 30 in the base which limits the total range of travel of the arm. The microswitches 27 and 28 are arranged to control the motor 19, the switch 27 switching the motor off and the switch 28 switching the motor on so that the motor 19 maintains the supply of strip around the roller 24 as the arm floats in between the micro-switches. The strip22then passes through a motor driven roller 23 engaged by a pinch roller 32 mounted on a pivotal arm 33 biassed against the drive roller by a spring (not shown).The strip then passes around an idler roller 34 through a photo-electric detector device 35 into the label printing mechanism 12. The label printing mechanism comprises a drum 36 on which there is embossed annular rows of type fount the drum being driven by a drive motor 37. The strip 22 is arranged to pass adjacent the periphery of the drum at a printing station indicated at 39 with the label to be printed facing the drum periphery. An inking ribbon 40 is fed from a motor driven supply reel 41 between the periphery of the drum and the labels and thence to a motor driven take-up spool 42.

On the opposite side of the label strip to the drum periphery of the printing station there is a set of solenoid controlled printing hammers which hit the label to be printed at the appropriate location in accordance with the rotational position of the drum 36 to print the required characters on the label.

Typically the information printed on the label will comprise the goods, the price per unit weight of the goods, date of sale, the date by which the goods must be consumed, the particular weight of the goods, the price of the goods together with that information encoded in bar codes. The strip then passes around a right-angled stripper block 43 which causes the printed label to detach from the strip and move to a label applying device which will be described below. The backing then passes around guide roller44to the underside of the drive roller 31 where it is held againstthe rollerbya pinch roller 45 mounted on a pivotal arm 46 spring biassed to hold the pinch roller 45 against the drive roller.The spring force holding the pinch roller 45 against the drive 31 is arranged to be slightly greater than that holding the pinch roller 32 against the drive roller 31. The backing 47 then passes to a motor drive take-up spool mounted on the base 10 and having a hub 48 and triangular backing plate 49.

Disposed immediately below the stripper block 43 there is a downwardly inclined gate 50 comprising two spaced apart limbs 50a,50b the upwardly inclined surfaces of which are formed with a series of vacuum ports connected to a source of vacuum (not shown). The upper end of the gate is disposed immediately below the corner of the stripper block 43 so that as a label is stripped from the block, the label is pushed by the backing strip passing around the corner of the block on to the upwardly inclined surface of the gate where it is held in place by the aforesaid vacuum. Atriangular shaped label applying drum 51 is mounted on a spindle 52 below the lower end of the gate 50. The spindle 52 is mounted in a bearing block 52a at one end of an arm 53 pivotally mounted at 54 on the base 10.The other end of the arm is connected to the piston rod 55 of a pneumatic ram 56 mounted on the base for a purpose described below. A stepper motor is mounted coaxial with the pivot 54 of the arm 53 and a belt drive 57 extends from an output pulley of the motor to a pulley on the spindle carrying the drum 51 to rotate the drum in accordance with the movement of the motor. The drum apices are each formed with a label applying pad 58 each of which has a label holding surface 59. Each surface 59 is of generally rectangular perimeter and is formed with a cavity 60 the perimeter 61 of which is inset fom the perimeter of the surface by a uniform amount around the surface so that the perimeter of the cavity is also generally rectangular.Each cavity 60 extends into the body of the respective pad 58 and communicates via a respective passageway 62 with a respective pressure port 63, the three pressure ports 63 being equally spaced around the spindle axis and facing the bearing block 52a. By means of an adaptor plate 64, the passageways 62 widen out at the ports 63 to a kidney shape 64 which are about two and a half times as long around the spindle axis as they are wide radially to the spindle axis. As the drum 51 rotates, each port 63 cyclicly communicates with a port 65 in the bearing block 52a, with a port 66 in the bearing block 52a and then is blocked. The port 65 is connected to a vacuum source V, and the port 66 is connected to a change-over valve 67 which can connect the port 66 either to the vacuum source V or a supply CA of compressed air.

Each cavity 60 is substantially closed by a plate 68 mounted in the cavity with the surface of the plate flush with the surface 59 of the pad and with a uniform width gap 69 between the perimeter of the plate and the perimeter of the cavity. The back of the plate and bottom of the cavity are so shaped that a uniform distribution of air from the passageway 62 is provided to create a skirt of air of uniform velocity around the skirt when air pressure is applied to the cavity 60.

The rotary drum 51 is positioned so that the path of the pads 58 runs through the gate 50 between the spaced limbs 50a,50b thereof and the drum is anti-clockwise so that the pad 58 lifts labels from the gate 50 as the drum is driven through the gate, the pad 58 being connected to the vacuum source V by means of the respective port 63 communicating with the vacuum port 65. The drum 51 is raised by contraction of the ram 56 towards the gate when a pressure pad 58 is moving into position to collect a label from the gate. The contraction of the ram is controlled by a screw adjuster 70 on the ram which limits the contraction of the piston rod 55 into the ram so that the registration of the pick-up surface 59 in the gate can be adjusted along the gate.This enables the surface to be positioned centrally with respect to the label on the gate whatever the depth of the label. Once the pressure pad 58 has moved slightly past the gate, the ram 56 is extended to drop the hub 51 downwardly to the bottom of its travel so that the extremity of the pressure pad 58 can clear the underside of the printing mechanism 12 disposed about the gate. The hub 51 then continues to rotate in an anti-clockwise direction to bring the pressure pad to a generally horizontal attitude.

During this rotation, the port 63 for the pad 58 carrying the label moves into communication with the port air/vacuum port 66, the valve 67 being arranged to connect the port 66 to the vacuum source. During this transfer from port 65 to port 66, the kidney shape 65 of the port 63 enables the connection to the vacuum source V not to be interrupted. The label applying apparatus is coordinated with the conveyor system referred to above so that when the pressure pad carrying a label arrives in the horizontal position, the article to which that label relates is disposed below the pressure pad.

The valve 67 is then operated automatically to connect the port 66 to the air supply CA to create a skirt of air flow from the pad 58 which drives the label downwardly on to the article. It has been found that a skirt of air in this form creates a stable force on the label and labels can be displaced up to six inches on to an article using this system. As the pad reaches the label apply position, the port 63 for the next pad comes into communication with the vacuum port 65.

Also, afterthe label has been applied and as the drum continues to rotate the valve 67 is returned to connect port 66 to the vacuum source V readyforthe port 63 ofthe next pad to come into communication vacuum via the port 66.

Claims (12)

1. A label applying device for applying selfadhesive labels to articles comprising a pad having a surface to receive a label, means to draw vacuum at the surface to hold a label on the surface, a slit extending around the surface in a closed path and means to apply air under pressure to the slit to create a jet of air in the form of a skirt to propel a label on the pad on to the surface of an article.

2. A label applying device as claimed in claim 1 wherein the means to draw vacuum at the surface of the pad is connected to the slit and valve means are provided for controlling the application of vacuum and air pressure to the slits to hold a label on the pad and to propel the label on to an article as required.

3. A label applying device as claimed in claim 1 or claim 2 wherein the slit follows path inset from the perimeter of the surface of the pad by a generally uniform distance around the perimeter of the surface.

4. A label applying device as claimed in claim 3 wherein the surface of the pad has a rectangular perimeter and the slit has a corresponding rectangular perimeter being inset by a uniform distance from the perimeter of the pad.

5. A label applying device as claimed in any of the preceding claims wherein the pad is formed with a cavity extending into the pad from said surface and the perimeter of which at the surface defines the outer periphery of the slit and a separate plate is mounted in the cavity having surface flush with the surface of the pad and a perimeter defining the inner periphery of the slit.

6. A label applying device as claimed in claim 5 wherein a passageway leads to the cavity for connecting vacuum and air pressure to the cavity and a gap is provided between the cavity and the back of the plate leading to the slit between the perimeter of the plate and the perimeter of the cavity at the surface of the pad, the gap being such that a substantially uniform air pressure is created in the slit to provide an air jet of uniform flow from the slit.

7. A label applying device as claimed in any of the preceding claims wherein the pad is formed on a rotary head for moving the pad between a label receiving station and a label delivery station, the valve means of the pad being arranged to apply suction at the slit in the label receiving position and air pressure at the slit in the delivery position.

8. A label applying device as claimed in claim 7 wherein a plurality of label applying pads are provided around the periphery of the rotary head.

9. A label applying device as claimed in Claim 8, wherein the valve means is arranged to connect each pad in turn as it advances to a suction source when the pad is at the label receiving station, to a suction source via a change-over valve when the pad is between the label receiving and delivery stations, and to pressure source via said change-over valve when the pad reaches the label delivery station.

10. A label applying device as claimed in Claim 8 wherein three pads are provided equi-spaced around the perimeter of the rotary head.

11. A label applying device as claimed in any of Claims 7 to 10, wherein the label receiving station and the label applying station are spaced apart by about one third of a turn around the rotary head.

12. A label applying device substantially as described with reference to and as illustrated in the accompanying drawings.