GB2186862A - Improved method and apparatus for finishing joints - Google Patents

Abstract

There is described a method of and apparatus for applying a jointing tape to a butt joint between panels, particularly suited to plasterboard jointing. The apparatus comprises a container 1 for joint finishing material in slurry form, through which a jointing tape is led from a reel 5. Emerging from the slurry, excess slurry is removed from the tape by scraper bars 9, 10 or rollers. The embodiments of the apparatus include a container having tape support and scraper means, a tape reel holder for use in a container (Fig. 3), providing a tape reel support and scraper surfaces, and a tape coating and dispensing package comprising a container, tape support and scraper means, a tape reel, and a quantity of finishing material (Fig. 4). Coated tape dispensed by the apparatus is applied manually to the joint. <IMAGE>

Description

SPECIFICATION Improved method and apparatus for finishing joints The present invention relates to the interior finishing of buildings and particularly concerns the jointing of plasterboard panels used in the "dry-lining" method of housebuilding.

Traditionally, after the brick structure of a house had been completed, the internal finishing was done by a plasterer who mixed and applied by hand a plaster layer over the internal faces of the walls of the house. This method, as well as requiring a highly-skilled craftsman to obtain good results, has the disadvantages of being a time-consuming process in that plaster is slow to apply and extremely slow to dry, requiring weeks to pass before decorating may commence.

To speed up the finishing process, the technique of "dry-lining" was developed in which, after completion of the bricks or block structure, the internal walls and ceilings are finished by fixing preformed plasterboard panels thereto. The panels are arranged in butting relationship, and where a bonding agent is used require only the time for their bonding agent to dry to complete the first stage of the process.

The second stage of the process is to cover the joints between the panels, to ensure a smooth and uniform surface to receive paint or other wallcovering.

Clearly, three types of joints will be encountered in most buildings and these are flat joints, externals and internals. As the name implies, a flat joint is a joint between two panels in the same plane. An external joint is the joint between two panels arranged at right-angles with the obtuse angle between them exposed, and an internal joint is a joint between two perpendicular panels such as may be found at the corner of a room.

Currently, jointing is done either by hand or by machine. In hand jointing, an application of a jointing material is made to the joint area and thereafter a jointing tape is laid over the join between the panels. When this has been smoothed into place using special tools, it is allowed to dry and thereafter a finishing coat of a joint-finishing material is applied and is then allowed to dry. In the machine jointing process, a hand-held dispenser applies a coating of jointing material to one side of a jointing tape, and by manipulation of the machine the tape is applied to the joint. After smoothing and initial drying, a second coat of finishing material is applied to the joint and final drying follows.

Joint finishing materials are normally supplied in powder form to be mixed with water to form a viscous slurry. The preferred material in the present case is "Joint Finish" manufactured by British Gypsum.

Various disadvantages are apparent in that the hand jointing method is protracted, involving four separate operations-coating the wall, applying the tape, smoothing and the final finishing application. The initial and final drying time must also be considered and their total reduces productivity considerably.

The machine jointing method involves the capital outlay for a complicated machine, requiring much attention to cleaning and maintenance, and has various operating difficulties.

As well as being relatively unwieldy, the machine dispenses coated tape to the wall and has means to cut the tape to length. The cutting blade is, however, remote from the dispensing point and thus the operator must cut the tape before the end of the joint is reached, taking care not to cut the tape too soon and leave an untaped gap at the end of the joint.

The present invention seeks to provide a method and apparatus to simplify the jointing procedure, particularly in respect of internal joints.

According to a first aspect of the present invention, a method for applying a jointing tape to a flat or angled butt joint between two panels comprises immersing a jointing tape in a joint finishing material, drawing the tape out of the material via a means for removing excess material, and applying the tape over the joint, Since prepared joint-finishing material is an aqueous slurry, the tape is preferably immersed as a roll, so that drawing tape off the roll serves to agitate the material to ensure its homogeneity. The tape is advantageously drawn off a roll supported in a container of the joint-finishing material, and passed round a guide roller immersed in the material to provide a long immersed path for the tape.The tape then passes out of the material where it is engaged first on one face then on the other by scraper bars which remove excess joint finishing material from the tape.

In another aspect of the invention there is provided apparatus for applying joint finishing material to a jointing tape, the apparatus comprising a container, preferably in the form of an eiongate trough, having means for supporting a roll of jointing tape and capable of being filled to a determined level with a joint finishing material in the form of a viscous aqueous slurry, the container being provided with means to define a tape path at least partially situated below said predetermined level, and having two tape-engaging surfaces situated above said predetermined level and capable of engaging respective faces of the tape to con trol the amount of joint finishing material adhering thereto.

The tape path may be defined by a plane tangential to the tape reel and contacting one of the tape-engaging surfaces.

Advantageously, the container may have one or more guide surfaces below the predetermined level to increase the immersed length of the tape path to ensure thorough impregnation of the tape.

The present invention also seeks to provide an improved apparatus for carrying out the method previously described, which makes the method more economical in use by removing initial capital outlay for the purchase of a special container for coating the tape.

According to a third aspect of the present invention, a tape reel holder for use in a container for applying a joint finishing material to a jointing tape comprises a body or framework providing a support for mounting a reel of tape for rotation about its axis, the body or framework further including two tape-engaging surfaces extending parallel to the said axis and capable of engaging respective faces of a tape led from a reel mounted on the support. In use, the container is filled to a predetermined level with a joint finishing slurry, the reel holder being so dimensioned that a reel of tape mounted on the support is at least partially immersed in the slurry when the reel holder is in position in the container, and the tape is led off the reel through the slurry to the tapeengaging surfaces which are positioned above said predetermined level.

The reel holder may be a substantially enclosed body, or may be an open framework and may be made from any suitable material.

In the former case, it is advantageous to form the body either from a suitably cut and folded card or metal blank or from plastics material, to provide a support and tape-engaging surfaces, and to contain a tape reel. Alternatively, plastics components may be positioned in a card body to provide the support and tape-engaging surfaces.

Such a reel holder, when used with a suitable container, would be simply discarded when the reel of tape is exhausted, a fresh holder complete with new tape reel being placed in the container. The body may be provided with engagement means to grip a side or an edge of the container to retain the reel holder in place. Alternatively, mounting means may be provided within the container to receive the reel holder. Such mounting means could comprise a mounting bracket attached to the inside of a conventional bucket by clamps, bolts, or by adhesive bonding. Alternatively the reel holder may be mounted to the underside of a hinged lid of the container, to be in its operating position when the lid is ciosed.

If the reel holder is a framework rather than an enclosed body, it may be made for example from a length of metal or plastics rod suitably shaped to provide a support and tape-engaging portions.

According to a fourth aspect of the invention, there is provided a totally self-contained apparatus for applying a jointing tape to a joint, wherein a tape reel is contained within a package together with a sufficient amount of joint finishing material, either in powder or slurry form, the package further providing means to support the tape reel and means to remove excess joint finishing material from the tape. The joint finishing material may be housed in a separate sealed compartment of the package to keep it from contacting the tape until the package is to be used.

The method and apparatus of the present invention will now be described in detail with reference to the accompanying drawings in which: Figure 1 is a sectional side view of a first tape coating and dispensing apparatus; Figure 2 is a perspective view of the apparatus of Fig. 1, cut away to show internal detail; Figure 3 is a diagrammatic perspective view of a tape reel holder, positioned within a container; Figure 4 is a perspective view of a second tape reel holder, in its operating position in a container; and Figure 5 shows a schematjc perspective view of a tape dispenser package.

Referring now to Figs. 1 and 2 of the drawings, a first embodiment of the apparatus comprises a trough 1 with side walls 2 and 2a, a vertical end wall 3 and an inclined end wall 4.

A roll of jointing tape 5 is supported on a bar 6 which extends across the trough 1 and is itself supported by a hook 7 engaging the top edge of side wall 2. The hook is removable from the trough for loading tape rolls on to the bar 6.

The jointing tape 5 is led off the roll and below a guide bar 8 positioned near the bottom of the trough 1. From there, the tape 5 extends upwardly to pass over a first scaper bar 9, under a second scraper bar 10 and out of the open top of the trough 1.

The guide bar 8 and scraper bars 9 and 10 are in this embodiment fixed cylindrical rods.

It is preferable that scraper bars 9 and 10 are fixed, but guide bar 8 may equally be a rotatable member. The cross-sectional shapes of the scraper bars 9 and 10 may be rounded or polygonal, but circular cylindrical bars have been found to give adequate results.

A carrying handle 11 may be provided for convenience. Any suitable material may be used for the construction of the device, sheet metal, wood and plastics materials being most convenient.

In use, the hook 7 is removed and a roll of tape 5 is loaded on to the bar 6 and positioned in the trough. The tape is then threaded under, over and under the bars 8, 9 and 10 respectively.

A quantity of joint-finishing material, in the form of a viscous slurry, is then poured into the trough to a level above the roll 5, but below the scaper bars 9 and 10. Scraper bar 9 is preferably set higher than scraper bar 10 to increase the arcs of contact between the tape and the scraper bars.

To tape the joint between two plasterboard panels, no preparation of the panels is necessary. Tape is simply pulled from the trough 1, and the operator gathers a manageable amount of tape in his hands. As will be apparent, passage of the tape 5 through the finishing materal will cause material to coat the faces of the tape when the tape emerges from the slurry. Passage of the tape over first scraper bar 9 removes excess material from a first surface of the tape, the material removed returning to the body of material in the trough. Passage under the second scraper bar 10 similarly removes excess slurry from the other face of the tape, returning the excess to the trough. The slurry is meanwhile agitated by the rotation of the roll 5 as the tape is removed, thus keeping the slurry well mixed.

Mixing paddles may be provided, rotated by the movement of the tape reel, to agitate the slurry.

The operator amasses a sufficient amount of tape to finish several joints, and carries it to the first joint site. The coated tape is then laid onto the joint, and torn off at the correct length. Smoothing the tape completes the operation and the operator moves on to the next joint.

The same method is used for flat and internal joints, with the tape being manually laid into the angle of an internal joint. Smoothing the tape with a conventional corner roller completes the joint.

Jointing tapes are perforated along the centre line to facilitate creasing, but are generally too stiff to tear and fold easily. An unexpected advantage of the present invention is that the immersion of the tape in the slurry softens the tape to an extent to which it can be easily folded or torn, but is not so weakened that it becomes unmanageable.

Using traditional hand-jointing methods for the flat joints, and the conventional jointing machine for corner joints, it may take an experienced craftsman three hours to complete the joints in a small house. As stated, however, the drying time for the materials then demands a delay of several days before decorating may begin. Using conventional joint finishing material and the apparatus and method of the present invention, it is estimated that the same house may be jointed in approximately two hours, thus saving the craftsman's time. More importantly, however, the joints are dry and ready for further treatment the next day, or even the same day. The avoidance of several days' waiting time thus achieved is an important advantage of the present method.

Referring now to Fig. 3, there is seen a container 12 such as a conventional bucket, having an open top 13, an inverted frusto conical sidewall 14, and a circular base 15.

The container wall 14 is cut away to expose a reel holder 16, comprising two spaced sides 17 and 18, joined by an end wall 19 and a base 20. The reel holder is open at its sides opposite end wall 19 and base 20. Within the reel holder 16, a tape reel 21 is supported on a bar 22 extending between the sides 17 and 18. Tape from the reel 21 is drawn off at the lower part of the reel, and extends horizontally to a tape guide 23 which extends between the sides 17 and 18. Passing round the guide 23, the tape is led upwardly towards a first scraper bar 24, round which it passes subsequently to extend around a second scraper bar 25. Scraper bars 24 and 25 are positioned to engage respective faces of the tape, before the tape is finally led upwards out of the reel holder and out of the open top 13 of the container 12.In use, a joint finishing material in the form of an aqueous slurry is used to fill the container to a predetermined level above guide bar 23 but below first scraper bar 24, preferably to a level such that the tape reel 21 is substantially immersed in the slurry. The apparatus is then used as described in the method expiained above.

To ensure stability of the tape reel holder 16 in the container 12, retaining means may be provided to fix the reel holder 16 in position. Such retaining means may be in the form of a plate (not shown) attached to the reel holder base 20 extending to cover the base 15 of the container, so that the weight of the slurry retains the plate and hence the reel holder down onto the container base. Alternatively, retaining means may be provided as one or more brackets extending from the container and releasably engaging the reel holder.

Such brackets may be fixed to the container by clamps, screws or by adhesive bonding, as appropriate.

The reel holder may have different configurations from that shown; it is envisaged that instead of scraper bars 24 and 25, the edges of suitably placed panels may be used to con trol the amount of slurry leaving the holder 16 with the tape. The tape may for example be led out of the holder 16 via a slit or slot, with the tape engaging both sides of the slit or slot to remove excess slurry.

The reel holder may be formed from an integral card or metal blank, or as yet a further alternative, the reel holder 16 may be a composite assembly of metal or card panels and plastics components or an assembly of entirely plastics parts providing a reel support, and tape-engaging surfaces, and optionally guide surfaces. Openings may be formed in the side or end panels of the reel holder to admit slurry to the interior to coat the tape.

In Fig. 4, an alternative embodiment of the reel holder is shown which comprises a framework formed from a metal rod. The rod is bent to form two parallel arms spaced by a distance substantially equal to the width of the tape to be used. A hook part 26 is formed at one end of the frame, from whence the arms 27, 28 extend horizontally then vertically down as seen in the figure. The vertical sections are formed with bends defining convergent portions 29, parallel adjacent portions 30, and divergent portions 31 which together form a support for a tape reel 32 by entering the open ends of the tape reel's axial bore 33.

The arms 27, 28 then extend obliquely upwards, and at their respective ends turn inwardly to provide two spaced parallel scraper portions 34, 35. Scraper portion 34 extends to contact arm 27, and may be attached thereto at its end. Scraper arm 35 has its free end bent over to form a hook 36, which ensures that the tape passes over scraper portion 35 as it is drawn from the reel. As is shown in phantom lines, the tape passes from the bottom of tape reel 32 over scraper portion 34, under scraper portion 35, and thence to the user.

The hook part 26 engages over the lip of the container, for example a conventional plastics bucket, to hold the reel holder in place.

The lower ends 37, 38 of the arms 27, 28 below the reel 32 may be arranged so as to engage the base of the bucket for added stability, As before, the container is filled with joint finishing slurry to a level above the bottom of the reel 32, but below the scraper portions 34, 35, and the tape drawn off and used as previously described.

Referring now to Fig. 5, there is seen a schematic perspective view of a tape coating and dispensing package 40, whose side and end are cut away to show the interior detail.

The package 40 is a substantially closed parallelepipedal fluid-tight container, having front, rear, top, bottom and end wails 45, 46, 47, 48, 49 and 50. An internal dividing wall 41 separates the interior of the package 40 into two chambers 42, 43.

In chamber 43, there is arranged a support for a reel of jointing tap, in the form of a bar 44 extending between the front wall 45 and the rear wall 46 of the package. A reel of tape T is mounted on the support bar for rotation about its axis.

Extending parallel to the support bar 44, and adjacent the bottom wall 48 of the package, is a guide bar 51. Two spaced scraper bars 52, 53 are positioned above the guide bar, adjacent the top wall 47 of the package 40. The scraper bars are arranged to engage the faces of a tape led from the reel T, below the guide bar 51, and respectively over and under the scraper bars 52, 53, before being led out of the package via an opening 54 in the top wall 47. Clearly, the exact disposition of the scraper bars may vary, provided that each of the faces of the tape engages a respective one of the scraper bars 52, 53. Similarly, the opening 54 may likewise be formed in the end wall 50 of the package rather than the top wall 47. A cover may be provided for the opening 54, the cover being removed before use of the package.

In chamber 42 of the package 40, there is contained a quantity of joint finishing material 55. The material 55 may be in the form of a dry powder, in which case an opening 56 may be provided in the top wall of the package for the addition of water to the powder to form a slurry. Alternatively, the dividing wall may be omitted and water added through the tape exit opening.

The material may alternatively be in the form of a premixed air-drying slurry, and may contain additives to prevent settling of the solids from the aqueous slurry during storage.

The dividing wall 41 of the container of Fig.

5 is provided with lines of weakness 57, which allow the dividing wall to be ruptured when the joint finishing material is required to coat the tape. In one embodiment, a tab (not shown) is attached to the dividing wall 41 and is led out of either tape exit opening 54 or the opening 56, so that by pulling the tab the dividing wall may be ruptured and the slurry allowed to flow into chamber 43 to coat the tape T. Alternatively a tool may be introduced into the package to rupture the dividing wall 41. It will be appreciated that the proportions of the package, and the relative volumes of the chambers 42 and 43, will be such that chamber 42 contains sufficient material to coat the entire tape T, and that the level of the slurry in chamber 43 will be higher than the guide bar 51 but lower than the lowest scraper bar 52 when the dividing wall 41 is broken.

In a further alternative embodiment of the package, the joint finishing material may be contained in a sealed bag, thus rendering the dividing wall 41 unnecessary. The bag may be within the package, in which case, the bag will be simply ruptured by a tool when the material is required to coat the tape. Alternatively, the sealed bag of premixed slurry may be separate and be supplied with the container. The user will simply empty the bag into the container prior to using the tape.

It will be understood that when utilising the tape coating and dispensing package, the operator needs no additional equipment to apply the tape. When jointing commences the operator using the illustrated package simply removes the cover on tape exit opening 54, to find the tape ready threaded round the guide and scraper bars 51, 52, 53. The dividing wall 41 is ruptured by the appropriate means described above, and coated tape may thereafter be drawn from the package and applied to the joint as described above. Clearly, if the material is supplied as a dry powder, there is the additional step of forming an opening 56 in chamber 42, preferably by removing a panel defined by weakened sections and provided with a pull tab, and adding the requisite amount of water to form a slurry. The dividing wall may then be ruptured and the coated tape drawn from the package.

Modifications of the embodiments described above are clearly possible without departing from the scope of the present invention as defined in the appended claims.

Claims (22)

1. A method for applying a jointing tape to a flat or angled butt joint between two panels, comprising immersing the tape in a joint finishing slurry, drawing the tape out of the slurry via a means for removing excess slurry from both faces of the tape, severing the required length of tape, and applying the impregnated tape over the joint.

2. A method according to claim 1, wherein the tape is wound on a roll at least partially immersed in the slurry.

3. A method according to claim 1 or claim 2, wherein the means for removing excess slurry from the tape comprises two fixed scraper bars which engage respective faces of the tape.

4. An apparatus for applying a joint finishing material in the form of a viscous aqueous slurry to a jointing tape, the apparatus comprising a container adapted to be filled to a predetermined level with the slurry, means to support a roll of tape, and tape-engaging means situated above the predetermined level and capable of engaging both faces of a tape to control the amount of slurry adhering thereto, the path of the tape from the tape roll to the tape-engaging means being arranged to extend for at least part of its length below said predetermined level.

5. An apparatus according to claim 4, wherein the tape roll is supported at least partially below said predetermined level, and tape is led from the immersed part of the roll.

6. An apparatus according to claim 4 or claim 5, wherein tape guide means are provided below the predetermined level to define the tape path.

7. An apparatus according to claims 4, 5 or 6, wherein the tape engaging means comprises a pair of scraper bars of polygonal or rounded cross-section.

8. An apparatus according to claims 4, 5 or 6, wherein the tape engaging means comprises a pair of panel edges.

9. An apparatus according to claim 4, wherein the means to support the tape roll and the tape-engaging means are formed as a sub-assembly selectively positionable in, and removable from, the container.

10. An apparatus as claimed in claim 9, wherein the sub-assembly is mounted on a lid hingedly connected to the container, the subassembly being held in within the container when the lid is closed, and being held clear of the container when the lid is open.

11. An apparatus according to claim 10, wherein the sub-assembly is a disposable package including a roll of tape, a tape roll mounting means, tape-engaging means, and means for holding the sub-assembly within the container.

12. Apparatus according to claim 4 in the form of a closed fluid-tight container having a selectively openable tape exit opening and containing a tape reel and a predetermined amount of joint finishing material, sufficient to coat the entire length of tape on the tape reel.

13. An apparatus according to claim 12, in which the joint finishing material is in powder form.

14. An apparatus according to claim 12, in which the joint finishing material is in slurry form, and is kept from contacting the tape reel during storage of the apparatus.

15. An apparatus according to claim 13 or claim 14, in which the container is divided into first and second chambers by a membrane which is ruptured when the joint finishing material is to contact the tape.

16. An apparatus according to claim 15, wherein the membrane is a dividing wall within the container.

17. An apparatus according to claim 15, wherein the membrane is a flexible sac positioned within the container.

18. An apparatus according to claim 15, in which the membrane includes a line of weakness.

19. A kit of parts comprising an apparatus according to claim 4 in the form of a first closed fluid-tight container having a selectively openable tape exit opening and containing a tape reel, in combination with a second fluid tight container containing sufficient joint finishing material to coat the tape on the tape reel.

20. A kit of parts according to claim 19, wherein the joint finishing material is a premixed air-drying slurry, and the second container is a flexible sac.

21. An apparatus substantially as described herein with reference to Figs. 1 and 2, Fig. 3, Fig. 4 or Fig. 5 of the accompanying drawings.

22. A method of applying a jointing tape, substantially as herein described.