WO2000015531A1

WO2000015531A1 - Apparatus for applying and cutting tape

Info

Publication number: WO2000015531A1
Application number: PCT/US1999/000612
Authority: WO
Inventors: Alan J. Craig; Anthony M. Rea
Original assignee: Minnesota Mining And Manufacturing Company
Priority date: 1998-09-15
Filing date: 1999-01-12
Publication date: 2000-03-23
Also published as: AU2222199A

Abstract

An apparatus (10) for applying tape (16) from a roll (14) onto a moving tape-receiving surface (8) includes an applying surface (78) biased toward the tape-receiving surface (8). This creates a nip between the applying surface (78) and the tape-receiving surface (8) and maintains the applying surface (78) adjacent the tape-receiving surface (8). The tape (16) is fed into the nip between the applying surface (78) and is pinched between the applying surface (78) and the tape-receiving surface (8). This enables the applying surface (78) to tack down the entire length of tape (16) including the leading edge and prevents bubbles and wrinkles from forming in the leading end of the tape (16). The tape (16) moves to the nip generally parallel to the tape-receiving surface (8) to reduce the relative speed between the tape (16) and the tape-receiving surface (8). The apparatus (10) can move among a home condition in which no tape (16) is applied or cut, an apply condition in which the tape (16) is applied, and a cut condition in which the tape (16) is cut.

Description

APPARATUS FOR APPLYING AND CUTTING TAPE

TECHNICAL FIELD

The present invention relates to tape-applying apparatus. More particularly, the present invention relates to apparatus for applying and cutting thick tapes.

BACKGROUND OF THE INVENTION

The mechanical application of adhesive tapes to various surfaces has many applications in the advertising, printing, packaging, automotive, implement, and construction industries. Other applications require tape possessing high performance characteristics. Known machines for applying adhesive tapes (such as machines including flat surface taping heads like T-645H, T-646H, and T-627 taping heads from Minnesota Mining and Manufacturing Company of St. Paul, MN) are adequate for applying thinner tapes like adhesive transfer tape (an unsupported adhesive film deposited on a silicone release liner) and double coated tape (a carrier coated with adhesive on each side on a silicone release liner) which are more easily cut. These systems, however, are unable to apply and to cut the thicker tapes like 3M™ VHB™ tapes and other tapes such as double-coated foam tape which are 0.081 - 0.305 cm (0.032 in - 0.120 in) thick.

U.S. Patent No. 2,906,426 discloses a mechanism which dispenses a fixed length of tape. The fixed length of tape is presented below the applying roller. Other known systems for dispensing, cutting, and applying tape, are known as flat surface applicators because they apply tape to flat surfaces. These systems allow the tape to be fed past the applying roller without the applying roller pressing the leading edge of tape against the surface on which the tape is applied, allowing the leading portion of the tape to become untacked. Subsequent action, such as a secondary buffing roller still permits air bubbles to form under this portion of tape, impairing the sealing function of the tape.

In known systems, the mechanisms for applying and cutting are linked, allowing little flexibility. Also, the tape is stationary as it contacts a moving product. The known machines can not provide the necessary dwell time to create the initial bond required to accomplish a smooth and accurate tape application.

SUMMARY OF THE INVENTION

The invention is an apparatus for applying tape from a roll onto a moving tape-receiving surface. The apparatus includes an applying surface which is biased toward the tape-receiving surface to create a nip and maintain the applying surface adjacent the tape- receiving surface. The tape is fed into the nip and is pinched between the applying surface and the tape- receiving surface. This enables the applying surface to tack down the entire length of tape including the leading edge and prevent bubbles and wrinkles from forming in the leading end of the tape. The tape is moved to the nip in a direction generally parallel to the tape-receiving surface to reduce the relative speed between the tape and the tape receiving surface. This increases the time of contact between the tape and the tape-receiving surface and increases the bonding of the tape to the tape-receiving surface.

A tape-applying member can move between a first position in which the tape is not in the nip and a second position in which the tape is placed in the nip. A cutter can cut the tape as the tape is applied onto the tape-receiving surface. The cutter moves independently of the tape-applying member such that varying lengths of tape can be cut on demand. The tape is pulled in a direction generally opposite to the direction of tape-receiving surface movement while the tape is cut. The cutting is controlled independently of the feeding. The apparatus can move among a first home condition in which no tape is being applied or cut, a second apply condition in which the tape is being applied, and a third cut condition in which the tape is cut. In the first condition the tape is threaded to the feeding mechanism. In the second condition the tape is fed into the nip. In the third condition the tape is cut. As the apparatus moves from the first condition to the second condition, the tape-applying member rotates from its first position to its second position to accelerate and position the end of the tape into the nip to apply the tape. As the apparatus moves from the second condition to the third condition, the tape-applying member rotates from the second position toward its first position and the knife arm rotates toward the cutoff support and pivots the knife into the tape path and adjacent the tape cut-off support to sever the tape. As the apparatus moves from the third condition to the first condition the tape-applying member moves to its first position and the knife rotates out of the tape path and the tape-applying member continues its rotation.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a side view of a tape applying apparatus of the invention in a home condition.

Figure 2 is a side view of the tape applying apparatus of Figure 1 in an apply condition. Figure 3 is a side view of the tape applying apparatus of Figure 1 in a cutting condition.

Figure 4 is a side view, partially cut away of part of the tape applying apparatus of Figure 1.

Figure 5 is a side view, partially cut away of part of the tape applying apparatus of Figure 1.

Figure 6 is a schematic view of a known tape applying apparatus.

Figure 7 is a schematic view of the tape applying apparatus of Figure 1.

DETAILED DESCRIPTION

The apparatus for applying and cutting tape can be used with high performance adhesive tapes such as 3M™ VHB™ tapes and other tapes, such as adhesive transfer tapes, double coated tapes, and foam tapes. Many of these tapes have high peel adhesion, high tensile holding power, high thickness, high viscoelasticity, stretch easily, and have low to fair initial adhesion and a conformability . Many of these properties make the tapes difficult to be handled by known applicators. The known applicators stretch many of these tapes during cutting and can not provide consistent tape placement because of the lower initial adhesion. For example, 3M™ VHB™ #4940 and 4941 tapes are 0.114 cm (0.045 in) thick, are difficult to handle because of the lower initial adhesion and are difficult to cut because of their high viscoelasticity. The apparatus of this invention can also be used for applying and cutting other hard to cut materials such as pressure-sensitive adhesive-backed hook and loop materials.

The apparatus 10 can include a drum or hub 12 on which a supply roll 14 of tape 16 is mounted for unwinding. The hub 12 is mounted on a frame 18. An articulated tape-applying member 20 including a primary portion 22 and a secondary portion 24 is mounted on the frame 18. The primary portion 22 has a first end 26, which is free, and a second end 28 at which the tape- applying member 20 is pivoted to the frame 18. The secondary portion 24 has a first end 30 and a second end 32, which are both free. The secondary portion 24 is pivotally mounted between its first and second ends 30, 32 to the first end 26 of the primary portion 22.

An actuating device, shown as a pneumatic cylinder 33 is connected to the primary portion 22 of the tape- applying member 20. Alternatively, the actuating device can be any known device, including, mechanical, electro-mechanical, electrical, and fluidic systems, such as solenoid valves, motors, linkages, and cams. The tape-applying member 20 as a whole rotates around the pivot point at the second end 28 of the primary portion 22. Additionally, the secondary portion 24 can be secured in its movement by a linkage system or a cam follower in a linear track to produce a combined traverse and rotational motion of the first end 30 of the secondary portion 24. A first tape-guide roller 34 is rotatably mounted on the first end 26 of the primary portion 22 of the tape-applying member 20. A second tape-guide roller 36 is rotatably mounted on the second end 28 of the primary portion 22. A third tape-guide roller 38 is rotatably mounted at an intermediate position of the secondary portion 24 of the tape-applying member 20. A fixed pin 40 is removably mounted to the first end 30 of the secondary portion 24. A tape-applying wiper 42 is affixed to the secondary portion 24 of the tape- applying member 20 opposite the third tape guide roller 38 and extends to the first end 30 of the secondary portion 24. The wiper 42 is held in its operating position by the fixed pin 40. The combination of the third tape guide roller 38, fixed pin 40, and the tape- applying wiper 42 forms and positions the end of the tape 16 for insertion into the nip.

An eccentrically-mounted tape anti-backup roller 44 is rotatably mounted on the second end 32 of the secondary portion 24 of the tape-applying member 20. A biasing device, such as a spring 46 biases the anti- backup roller 44 toward the first tape guide roller 34, close to the point of tape application. The anti- backup roller 44 prevents the tape from being pulled backward through the apparatus 10 and creating slack causing it to become unthreaded and misapply. An arm 47 extends from the anti-backup roller 44 and presses against another part of the system to increase the gap between the anti-backup roller 44 and the first tape guide roller 34 as will be explained below.

A knife arm 48, having a first end 50 and second end 52, is rotatably mounted to the frame 18 through a pivot intermediate its first and second ends 50, 52. A knife 54 or other cutting device is mounted on the first end 50 of the knife arm 48. The second end of the knife arm 48 is connected to an actuating device, shown as a pneumatic cylinder 56 (although other actuating devices can be used, as explained above) . A tape cut-off support 58 is fixed to the frame 18 and is located at the tape cut-off point. A tape cutting device lubricator 60, such as felt, is fixed to the cut-off support 58 at the tape cut-off point. A dancer arm 62 has a first end 64 and a second end 66. The dancer arm 62 is rotatably connected at its first end 64 to the frame 18 at the same point as the second end 28 of the primary portion 22 of the tape-applying member 20. The second end 66 of the dancer arm 62 is a free end and houses a dancer roller 68. The second end 66 of the dancer arm 62 is biased in a counterclockwise direction in the figures. It is biased by any known biasing device connected to the primary portion 22 of the tape-applying member 20, such as a spring 70.

A tape application nip roller arm 72 is pivotably mounted to the frame 18 and is adjustably biased toward a surface 8 to be taped, such as by a spring 74. The nip roller arm 72 is preloaded such as with a screw 75. A stop member 76 prevents excessive movement toward the surface 8. A nip roller 78 is rotatably mounted at the free end of the nip roller arm 72. The nip roller 78 pulls the tape through the apparatus 10 during application. In alternative embodiments, the nip roller 78 can be driven at the same speed as the surface 8.

Additional tape guiding rollers 80, 82 can be used to guide the tape between the supply roll 14 and the dancer roller 68. Also, optional buffing rollers can be used to press the tape 16 onto the surface 8 to ensure proper adhesion. As shown, a leading buffing roller 84 can be located on the end of a pivoting, biased buffing roller arm 86 and a trailing buffing roller 88 can be located on the end of a pivoting, biased buffing roller arm 90.

In operation, the apparatus moves among several conditions. In a first condition shown in Figures 1 and 4, the home condition, no tape is applied or cut. In a second condition shown in Figures 2 and 5, the apply condition, tape is applied. In a third condition shown in Figure 3, the cut condition, tape is cut.

In the home condition of Figures 1 and 4, the tape 16 is already threaded from the tape supply roll 14, around rollers 80, 82 and around the dancer roller 68. The tape 16 next passes around the second tape guide roller 36 on the tape-applying member 20 and then around the first tape guide roller 34 and between the first tape guide roller 34 and the anti-backup roller 44. The tape 16 then passes over the third tape guide roller 38 and past the wiper 42 and the pin 40.

Upon receiving a start signal from a control device (not shown, such as photoelectric sensors, and limiter switches) that can determine the tape length and how often to apply the tape, the applying cylinder 33 rotates the tape-applying member 20 to the apply position of Figures 2 and 5. This accelerates and positions the end of the tape 16 into the nip between the nip roller 78 and the surface 8 being taped. This position of the tape 16 is best shown in Figure 7.

As the apparatus 10 is moving from the home condition to the apply condition, the arm 47 on the anti-backup roller 44 presses against the cutoff support 58, as best shown in Figure 5, to rotate the anti-backup roller 44 to increase the gap between the anti-backup roller 44 and the tape guide roller 34 and reduce the drag on the tape 16. Alternatively, the anti-backup roller 44 can be a one-way roller, operating without increasing the gap between it and the tape guide roller 34.

After a pre-determined length of tape 16 has been dispensed, a signal from the control device operates the applying cylinder 33 to move the tape-applying member 20 and return the apparatus 10 to the home condition. As the apparatus 10 moves from the apply condition, the anti-backup roller 44 moves toward the first tape guide roller 34 to create a nip that prevents the tape 16 from backing up through the apparatus 10, as best shown in Figure 4. During the movement back toward the home condition, the apparatus 10 reaches the cut condition of Figure 3. When the cut condition is sensed, a signal (from another or the same control device) operates the pneumatic cylinder 56 to move the knife arm 48 clockwise toward the cutoff support 58. The knife arm 48 pivots the knife 54 into the tape path and adjacent the tape cut-off support 58, severing the tape 16. The knife 54 continues through the tape 16 and contacts the tape cutting device lubricator 60. After a short dwell time, the knife 54 rotates counterclockwise out of the tape path. During that dwell time, the tape-applying member 20 completes its travel, separating the tape end and the knife 54. As the trailing end of the tape 16 passes beneath the nip roller 78, it can be buffed to the surface 8. The threading and the orientation of the leading end of tape 16 through the tape-applying member 20 is at an appropriate angle so that it approaches the nip roller 78 at or as close to the nip as possible. The leading end of tape 16 is directed in a path from its start point downward to the nip. Thus, the tape 16 moves in a direction generally parallel to the surface 8 being taped, in the same direction, as shown in Figure 7. In contrast, in the system of the '426 patent, shown schematically in Figure 6, the tape is brought down toward the surface in a direction that is generally perpendicular to the surface. There is more relative movement and more relative speed between the tape 16 and the surface 8. Because the tape 16 is fed to the nip roller 78 into the nip between the nip roller 78 and the surface 8 being taped, the tape is pinched in the nip. Because the spring 74 keeps the nip roller 78 in contact with the surface 8, different thickness tapes can be applied with consistent results. Eliminating any gap between the nip roller 78 and the surface 8 when the tape 16 is initially applied prevents the formation of air bubbles under this portion of tape and improves tape sealing. (Figure 6 shows the '426 patent system with a gap between the applying roller and the surface at the initial tape contact. Even using a downstream buffing roller does not remove all air bubbles created by this apparatus . )

The nip roller 78 always creates the nip. It is always contacting the tape 16 on the surface 8 when the tape is being applied. Additionally, the tape 16 is cut upstream of the nip roller 78. This means that, unlike some known systems, the tape 16 is never pulled off of the surface 8 after it is applied. Also, the knife arm 48 is not connected to the first tape guide roller 34. The knife arm 48 moves independently of the first tape guide roller 34; they are separately operated, such as by a computer. During cutting, the tape-applying member 20 pulls the tape 16 in a direction generally opposite to the direction of tape- receiving surface movement while the knife 54 cuts the tape 16 to prevent the tape from adhering to the knife.

Claims

1. An apparatus 10 for applying tape 16 from a roll 14 onto a moving tape-receiving surface 8 comprising: an applying surface; means for biasing the applying surface toward the tape-receiving surface 8 to create a nip between the applying surface and the tape-receiving surface and to maintain the applying surface adjacent the tape- receiving surface 8; and means for feeding the tape into the nip between the applying surface and the tape-receiving surface to pinch the tape between the applying surface and the tape-receiving surface and enable the applying surface to tack down the entire length of tape including the leading edge and prevent bubbles and wrinkles from forming in the leading end of the tape.

2. The apparatus 10 of claim 1 wherein the means for feeding the tape comprises means for moving the tape to the nip in a direction generally parallel to the tape-receiving surface to reduce the relative speed between the tape and the tape receiving surface thereby to increase the time of contact between the tape and the tape-receiving surface and increase the bonding of the tape to the tape-receiving surface.

3. The apparatus 10 of claim 2 wherein the means for moving the tape comprises a tape-applying member 20 which can move between a first position in which the tape is not in the nip and a second position in which the tape is placed in the nip.

4. The apparatus 10 of any of claims 1, 2, or 3 further comprising: means for cutting 54 the tape 16 as the tape is being applied onto the tape-receiving surface 8, wherein the means for cutting moves independently of the means for feeding the tape such that varying lengths of tape can be cut; and means for pulling the tape in a direction generally opposite to the direction of tape-receiving surface movement while the means for cutting is cutting the tape to prevent the tape from adhering to the means for cutting the tape.

5. The apparatus 10 of claim 4 further comprising means for controlling the means for cutting and for controlling the means for feeding independently of each other.

6. The apparatus 10 of claim 1 further comprising means for creating relative movement between the tape-receiving surface 8 and the applying surface.

7. The apparatus 10 of claim 1 wherein the means for biasing the applying surface comprises means for adjusting the biasing force.

8. The apparatus 10 of claim 1 wherein the applying surface comprises a roller 78.

9. The apparatus 10 of claim 4 wherein the tape- applying member 20 moves the tape 16 to the nip in a direction generally parallel to the tape-receiving surface 8 to reduce the relative speed between the tape and the tape receiving surface thereby to increase the time of contact between the tape and the tape-receiving surface and increase the bonding of the tape to the tape-receiving surface.

10. The apparatus 10 of claim 1 wherein the apparatus moves among a first condition in which no tape is being applied or cut and the tape is threaded to the means for feeding, a second condition in which the tape is fed to the nip and is being applied, and a third condition in which the tape is cut.

11. The apparatus of claim 10 wherein the means for feeding the tape comprises a tape-applying member 20 which can move between a first position in which the tape is not in the nip and a second position in which the tape is placed in the nip; further comprising means for cutting 54 the tape as the tape is being applied onto the tape-receiving surface, wherein the means for cutting moves independently of the means for feeding the tape such that varying lengths of tape can be cut on demand and comprises a knife and a cut-off support; and wherein as the apparatus moves from the first condition to the second condition, the tape-applying member rotates from its first position to its second position to accelerate and position the end of the tape into the nip to apply the tape; as the apparatus moves from the second condition to the third condition, the tape-applying member rotates from the second position toward its first position and the knife arm rotates toward the cutoff support and pivots the knife into the tape path and adjacent the tape cut-off support to sever the tape; and as the apparatus moves from the third condition to the first condition the tape- applying member moves to its first position and the knife rotates out of the tape path and the tape- applying member continues its rotation.

12. The apparatus 10 of claim 10 wherein the means for feeding the tape comprises means for moving the tape to the nip in a direction generally parallel to the tape-receiving surface to reduce the relative speed between the tape and the tape receiving surface thereby to increase the time of contact between the tape and the tape-receiving surface and increase the bonding of the tape to the tape-receiving surface.