Bag tying machine

Abstract

 A machine for applying an adhesive tape tie to a filled bag comprises at least one pair of counter-rotating wheels 16, 17 to feed the end of a filled bag forwards into a containment zone29 in which'ttisgatheredtogether,asingleadhesivetape , strip at the front of the containment zone 29 with its adhesive side facing the counter-rotating wheels 16, 17, and a pair of spring biased, pivoted clamping jaws 24, 28 in front of the adhesive strip. The pair of spring biased, pivoted clamping jaws 24,28 are mounted on a movable carriage 25 arranged to move backwards and forwards to move the pivoted clamping jaws 24,28 backwards and forwards through the containment zone 29. In so doing the jaws 24,28 pass around the gathered together neck of the bag and wrap the single adhesive tape strip around the gathered together neck of the bag to form a tie.

Description

[0001] Our earlier British Patent Specifications GB-A-1 381 871 and GB-A-1 517 031 both relate to machines for closing a filled bag by a closure formed by a length of adhesive tape. In the machines described in both of these patent specifications, the open end of a filled bag to be closed is introduced into an elongate nip formed between an opposed pair of endless belts. When the end of the bag is held in the elongate nip, a pusher travelling faster than the speed of the belts moves along the nip of the belts gathering together the end of the bag. The pusher then continues to push the gathered together end of the bag through a mechanism which wraps adhesive tape around the gathered together neck of the bag to form the adhesive tape tie. The pusher is then moved away from the nip and returned to a starting position upstream from the nip to enable it to gather together the end of a following bag to be filled.

[0002] In the machine described in GB-A-1 571 021 and that described in the second example of specification GB-A-1 381 871 the pusher also urges the gathered together neck of the bag into contact with the adhesive tape and urges the bag and adhesive tape between an opposed pair of jaws to wrap the adhesive tape around the gathered together neck of the bag. In the first example described in GB-A-1 381 871 .the pusher remains in its advanced position and supports the gathered together neck of a filled bag whilst an opposed pair of jaws moves towards the gathered together neck of the filled bag and wraps adhesive tape around the gathered together neck of the filled bag to tie it.

[0003] The opposed pair of endless belts and the pusher and its associated driving mechanism are extensive and occupy well over half the length of the bag tying machine in the direction of travel of the filled bag. Also, the mechanism to move the pusher has to be capable of driving the pusher in a position aligned with the nip between the opposed pairs of belts and also of returning the pusher in a position offset from the nip between the opposed feed belts. This means that the driving mechanism for the pusher has to be relatively complicated.

[0004] US-A-2 840 967 describes another bag closing machine which forms an adhesive tape tie on the gathered together neck of a filled bag. In this example the open necks of filled bags are fed between opposed pairs of counter-rotating wheels and gathered together in a containment zone between the wheels and adhesive strips supported by a pair of spring-loaded jaws. After the neck of the bag has been gathered together it is driven between the spring-loaded jaws by moving the opposed pairs of counter-rotating wheels in the feeding direction of the bags. US-A-2 867 067 which is a later filed case by the same inventors as US-A-2 840 967 describes this bag closing and sealing arrangement as not being satisfactory for closing large bags such as those used in packaging potatoes, apples and oranges. US-A-2 867 067 describes a bag tying and sealing machine in which the neck of a filled bag is gathered together by opposed pairs of counter-rotating wheels, the rotational axes of which remain stationary, and then a hook-shaped arm engages the gathered together neck of a filled bag and drags it between a pair of opposed spring-loaded jaws which apply - strips of adhesive tape to the gathered together neck of the filled bag to tie it. Naturally the hook-shaped arm fulfils a similar function to the pusher in our earlier specifications GB-A-1 301 871 and GB-A-1 517 031 in driving the gathered together neck of a filled bag between a pair of spring-loaded jaws which apply adhesive tape to the gathered together neck of a filled bag.

[0005] According to this invention a machine for applying an adhesive tape tie to a filled bag comprising at least one pair of counter-rotating wheels to feed the end of a filled bag forwards into a containment zone in which it is gathered together, adhesive tape at the front of the containment zone with its adhesive side facing the counter-rotating wheels, and a pair of spring biased, pivoted clamping jaws in front of the adhesive tape, also includes a movable carriage on which the spring biased, pivoted clamping jaws are mounted, the movable carriage being arranged to move backwards and forwards to move the pair of clamping jaws backwards and forwards through the containment zone, and in so doing passing around the gathered together neck of the bag and wrapping the adhesive tape around the gathered together neck of the bag to form a tie.

[0006] In the bag tying machine in accordance with this invention the rotational axes of two counter-rotating wheels which gather together the open neck of a filled bag are fixed in position. The jaws which apply the adhesive tape tie to the gathered together neck of a filled bag move around the gathered together neck of the bag to apply the adhesive tape without the neck of the bag having to be moved. This contrasts with the arrangement shown in US-A-2 840 967 and US-A-2 867 067. In the first of these the gathered together neck of the bag is moved by moving the rotational axes of the opposed pairs of wheels and in the second the hook-shaped arm pulls the gathered together neck of the bag through the tie forming arrangement. By keeping the neck of the bag stationary during application of the adhesive tape tie the weight of the contents of the bag do not have any influence on the formation of the tie and it is believed that this is the reason why the machine in accordance with this invention does not suffer from the shortcomings of that described in US-A-2 840 967.

[0007] The backwards and forwards movement of the movable carriage carrying the clamping jaws is typically only the same length as the finished adhesive tape tie and is very much shorter than the movement of the pusher described in our earlier patent specifications GB-A-1 381 871 and G_B-A-1 517 031. Thus the overall length of the machine in accordance with this invention as compared with our earlier machines is at least halved. Another advantage is that the pusher or its equivalent hook-shaped arm is omitted entirely and this simplifies the construction of the machine considerably since there is one less item present at the location at which the tie is applied to the neck of the bag.

[0008] A further advantage of a machine in accordance with this invention is that it no longer has to operate in synchronism with a flighted conveyor. In our earlier machines the products are fed by a flighted conveyor and the movement of the pusher is synchronised with the movements of the flights of the flighted conveyor. The machine in accordance with the present ivnention, by avoiding the pusher and feed belts and avoiding the need for moving the neck of a bag during application of the tie can also avoid the need for the flighted conveyor.

[0009] Preferably the containment zone formed between the pair of counter-rotating wheels and the clamping jaws is further defined by a pair of fingers extending upstream from the upstream tips of the clamping jaws beyond the nip between the pair of counter-rotating wheels. In this case, preferably only a single strip of adhesive tape passes through apertures in the opposed fingers.

[0010] Preferably there are two pairs of counter-rotating wheels separated from one another and located on both sides of the path of movement of the clamping jaws and fingers. The corresponding wheels of each pair may share a common hub but preferably the driven wheels share a common hub and the other wheels of each pair are not directly driven and are mounted for independent movement. Preferably the other wheels of each pair are independently spring biased against the driven wheels. Preferably the wheels each include a contact surface formed of rubber or other elastomeric material bonded to the remainder of the wheels to provide a surface which grips the end of the filled bag to be sealed.

[0011] Preferably the machine includes only a single motor to drive the counter-rotating wheels, the movable carriage and means to provide the adhesive tape strip. In this case, the movable carriage and the means to provide the adhesive tape strip are preferably operated from the single, continuously operating motor by a pair of single revolution clutches. Operation of the clutches is preferably triggered by a detector which detects the presence or absence of a bag in, or immediately upstream of, the containment zone.

[0012] Preferably the machine also includes a printer to print information onto the non-adhesive surface of the adhesive tape, the printer being substantially as described in our earlier Patent Specification GB-A-1 516 499. Preferably the adhesive tape is provided with spaced pieces of non-adhesive material such as paper and the single adhesive strip is provided by a gripper arrangement _'similar to that disclosed in our earlier Specification GB-A-1 381 871 and GB-A-1 517 031.

[0013] The machine in accordance with this invention is very much smaller, lighter and more convenient to use and as a result of this it, together with its associated conveyor belt, may be easily inclined to the horizontal so that bags filled with loose commodities, for example vegetables such as potatoes or carrots can be easily accommodated by the conveyor and readily closed by such a machine.

[0014] A combined bagger and sealer including a bag tying machine in accordance with this invention will now be described with reference to the accompanying drawings, in which:-

Figure 1 is a front elevation of the combined bagging and sealing machine;

Figure 2 is a plan of a combined bagging and sealing machine;

Figure 3 is a front elevation of the bag tying portion of the machine;

Figure 4 is a side elevation of the bag tying portion of the machine from one side;

Figure 5- is a-side elevation of a bag tying machine from the other side;

Figure 6 is a front elevation of a detail of the bag tying machine drawn to a larger scale;

Figure 7 is a vertical section through part of the bag tying machine again drawn to a larger scale; and,

Figure 8 is a section through the part of the bag tying machine taken along the line A-A shown in Figure 3.

[0015] The combined bagger and sealer consists of a manual bagger station 1 in which products such as loaves of bread are placed manually in polythene bags 2 which are held in a wicket 3. After having been placed in the bags 2 the products are manually pushed forwards onto a belt conveyor 4. _'A bag tying machine 5 is located beside the belt conveyor 4 and includes a bag entry portion 6 including a pair of counter-rotating brushes into which the open necks of the filled bags pass.

[0016] The bag tying machine includes a reel of adhesive tape 7 and a reel of paper tape 8. Adhesive tape from the reel 7 passes through a hot foil blocking type print unit 9 to a pair of feed rolls 10. The paper tape from the reel 8 passes through a pair of feed rolls 11 and is brought into contact with the adhesive tape upstream from the feed rolls 10. The paper and adhesive tape supply mechanism includes two pairs of cutting blades 12 and 13 and a gripper unit 14 which grips the free end of the tape and holds it across the path of the ends of the bag to be closed. The adhesive and paper tape supply mechanism is substantially the same as that described in our earlier patent specifications GB-A-1 381 871 and GB-A-1 517 031 and will not be described in detail. The gripper unit 14 is opened and closed by actuation of a pneumatic cylinder 15.

[0017] The open end of a bag to be filled is drawn into a .bag entry by the counter-rotating brushes 6 and then it passes into the nip between the two pairs of counter-rotating wheels 16 and 17. The pair of wheels 16 share a common hub shown most clearly in Figures 4 and 7 and are driven continuously by an electric motor 18, again shown in Figure 7, via a toothed belt 19. The pair of wheels 17 are freely rotatably mounted upon a pair of pivoted arms 20 that are biased by springs 21 to urge the wheels 17 against the wheels 16. The wheels 16 and 17 both include rubber tyres 22 and 23.

[0018] The bag tying mechanism also includes a pair of pivoted clamping jaws 24 which are mounted on a carriage 25 which is movable along a slide 26 towards and away from the wheels 16 and 17. The pivoted clamping jaws 24 are spring biased by compression springs 27 and include curved abutment faces 28. Extending finger portions 29 extend from the curved abutment faces 28 towards and in between the wheels 16 and 17 to define a containment zone. The extending fingers 29 include apertures to allow the gripper unit 14 to pass through to grip the free end of the adhesive and paper tapes from below the feed rolls 10 and draw the length of adhesive tape through the apertures in the fingers 29 so that it lies between the nip of the wheels 16 and 17 and the abutment faces 28.

[0019] In use, as the open end of a filled bag is fed into the nip between the wheels 16 and 17 these wheels grab the end of the filled bag and feed it into the containment zone defined by the fingers 29, the strip of adhesive tape and the periphery of the wheels 16 and 17. The end of the filled bag is thus gathered together in the containment zone. To form an adhesive tape tie around the gathered together end of the bag the clamping jaws 25 are moved towards the wheels 16 and 17 and in so moving the curved abutment faces 28 press the adhesive tape around the gathered together neck of the filled bag so wrapping the adhesive tape around the gathered together neck of the filled bag. Then, further movement in this direction of the clamping jaws adheres the adhesive side of the free ends of the strip of adhesive tape to one another so that the free ends are adhered to one another to complete the tie. The gathered together neck of the bag is thus held substantially stationary as the tie is formed around it. The clamping jaws 24 then retract as the carriage 25 returns to its initial position and this return movement moves the closed end of the filled bag which is now on the opposite side of the curved abutment surface 28 away from the wheels 16 and 17. Whilst the tie is being formed the product in the body of the bag is moving on the continuously moving plain conveyor 4, possibly with some slight skewing of the product with respect to the direction of movement of the conveyor 4 as its gathered together neck is held stationary whilst the tie is formed. The movement of the product along the conveyor 4 completes the movement of the gathered together and closed neck of the filled bag away from the bag tying machine 5.

[0020] The operation of the bag tying mechanism is triggered by a bag detector immediately upstream of the nip between the wheels 16 and 17. The detector consists of a lightly spring biassed pivoted arm 30 and an associated proximity switch 31. The bag neck in entering the nip between the wheels 16 and 17 moves the arm 30 out of the path of the bag neck and then, as the last part of the bag enters the nip the arm 30 returns into the path of the bag and, in so doing moves away from the proximity switch 31 and triggers the bag tying mechanism. The proximity switch 31 actuates a single revolution clutch 32 which is shown in Figure 7 and which is driven via a toothed belt 33 from the electric motor 18. The single revolution clutch thus allows a shaft 34 to rotate through one complete revolution and in so doing this rotates a crank wheel 35 which, via a link 36 moves a carriage 37 along the slide 26 and thus moves the. clamping jaws 24 towards and away from the wheels 16 and 17. The shaft 34 also carries three cams 37, 38 and 39 which act together with associated proximity switches 40, 41 and 42 to actuate the cutters 12 and 13 and to actuate the pneumatic cylinder 15 to release the grippers 14; to actuate the printer unit 9; and, finally to operate a second single revolution clutch 43, shown in Figure 8, which is also driven by the toothed belt 33. The single revolution clutch 43 rotates a shaft 44 through one complete revolution and this drives the gripper 14 via a crank wheel 45 and associated links 46, 47 and 48 to drive the gripper unit 14 up and down. The shaft 44 also carries a further cam 49 which co-operates with a proximity detector 50 to de-actuate the pneumatic cylinder 15 to close the gripper unit at the top of its travel so that it grips the free end of the adhesive tape and on the return stroke of the gripper unit 14 the adhesive tape is pulled across the path of the neck of the bag. The single revolution clutches 32 and 43 are typically those marketed under Model No C2 P5-CCW-24-3-1 by Motion Control Incorporated of Rockford, Illinois, United States of America.

Claims

1. A machine for applying an adhesive tape tie to a filled bag comprising at least one pair of counter-rotating wheels (16, 17) to feed the end of a filled bag forwards into a containment zone (29) in which it is gathered together, adhesive tape at the front of the containment zone (29) with its adhesive side facing the counter-rotating wheels (16, 17) and a pair of spring biased, pivoted clamping jaws (24, 28) in front of the adhesive tape, characterised in that the spring biased, pivoted clamping jaws (24, 28) are mounted on a movable carriage (25) arranged to move backwards and forwards to move the pair of clamping jaws (24, 28) backwards and forwards through the containment zone, and in so doing passing around the gathered together neck of the bag and wrapping the adhesive tape around the gathered together neck of the bag to form a tie.

2. A machine according to claim 1, in which the containment zone formed between the pair of counter-rotating wheels (16, 17) and the clamping jaws (24, 28) is further defined by a pair of fingers (29) extending upstream from the upstream tips of the clamping jaws (28) beyond the nip between the pair of counter-rotating wheels (16, 17), and in which a single strip of adhesive tape passes through apertures in the opposed fingers.

3. A machine according to claim 1 or 2, in which there are two pairs of counter-rotating wheels (16, 17) separated from one another and located on both sides of the path of movement of the clamping jaws (24, 28).

4. A machine according to claim 3, in which one of the wheels (16) of each pair share a common hub and are driven and the other wheels (17) of each pair are not directly driven and are independently spring biased against the driven wheels (16).

5. A machine according to any one of the preceding claims, in which the wheels (16, 17) each include a contact surface (22, 23) formed of rubber or other elastomeric material bonded to the remainder of the wheels to provide a surface which grips the end of the filled bag to be sealed.

6. A machine according to any one of the preceding claims, in which the machine includes only a single motor (18) to drive the counter-rotating wheels (16, 17), the movable carriage (25), and means (10, 11, 14) to provide the adhesive tape.

7. A machine according to claim 6, in which the movable carriage (25), and the means (10, 11, 14), to provide the adhesive tape strip are operated from the single, continuously operating motor (18) by a pair of single revolution clutches (30, 43).

8. A machine according to claim 7, in which operation of the clutches (32, 43) is triggered by a detector (30, 31) which detects the presence or absence of a neck of a filled bag in, or immediately upstream of, the containment zone.

9. A machine according to any one of the preceding claims, which also includes a printer (9) to print information onto the non-adhesive surface of the adhesive tape.

10. A machine according to any one of the preceding claims, in which the adhesive tape is provided with spaced pieces of non-adhesive material such as paper to provide tabs at free ends of the adhesive tape tie to facilitate opening of the tie.

Drawing