GB2261897A

GB2261897A - Process for covering a profiled elongate member

Info

Publication number: GB2261897A
Application number: GB9117887A
Authority: GB
Inventors: Bryan Garner Mcdougall
Original assignee: Leaderflush Doors Ltd
Current assignee: Leaderflush Doors Ltd
Priority date: 1991-08-19
Filing date: 1991-08-19
Publication date: 1993-06-02
Anticipated expiration: 2011-08-19
Also published as: DE4227450A1; GB2261897B; GB9117887D0; FR2680497A1; DE4227450C2; FR2680497B1

Description

1 is 2 2 2 J) 1 Y? 7 1 This invention relates to a method and a machine

for applying a def ormable sheet material to elongate members of recessed cross-section to provide a continuous covering thereof, particularly where the elongate member is in the f orm of a shaped f rame member such as a door post or mullion.

An aim of the invention is -to provide encasement of an elongate member, f or example, a f rame member f or use in constructing a door frame, by a continuous covering. Continuous wrapping about a non-recessed profile such as a rectangular prof ile is well known in the art. However, continuous wrapping into a shoulder recess is a much more difficult problem particularly when using a contact adhesive, since the covering material needs to intimately follow the contour of the recessed portion of the elongate member.

In one aspect the present invention provides a process for encasing an elongate member with an encasement formed from a single sheet of deformable material. the elongate member having a recessed profile defined by at least one shoulder having an inwardly directed wall and an outwardly directed wall, the process including coating the surfaces of the elongate member which are to be encased in a contact 1 1 2 adhesive, coating one face of said sheet with contact adhesive, presenting the sheet to the elongate member so as to adhere the sheet to the elongate member with a marginal portion of the sheet overlying a shoulder on the elongate member which is to be encased, folding the marginal portion to contact the inwardly directed wall while shielding the remainder of the marginal portion from contacting the outwardly directed wall and subsequently permitting the remainder of the folded marginal portion to contact the outwardly directed wall to thereby form a continuous covering of said shoulder by said encasement.

Preferably the folding of the marginal portion is achieved by longitudinally feeding the elongate member with the sheet portion bonded thereto passed folding means on the marginal portion which applies pressure which is directed inwardly of the elongate member,, resistance to said pressure being achieved by guiding the elongate member along the rail means which engage with one or more longitudinally extending grooves formed in the elongate member.

In another aspect the invention provides apparatus comprising a fo lding station at which the marginal portion of the-sheet is folded to encase said shoulder, conveying means for conveying the elongate member longitudinally passed the folding station and guide rail means extending along the conveying means and adapted to engage with the 3 elongate member for guiding its movement passed the folding means and provide a reaction against inwardly directed forces on the elongate member.

In another aspect the invention provides an elongate member having a recessed profile defined by at least one shoulder having an inwardly directed wall and an outwardly directed wall, an encasement formed from a single sheet of deformable material bonded by contact material to said walls to provide a continuous covering for said shoulder.

The sheet material may in be the form of a plastics sheet material such as polyvinylchloride, a laminate or a wood veneer.

Exemplary embodiments of the invention will now he described with reference to the following drawings, in which:

Figure 1 represent a schematic perspective view of the apparatus according to one embodiment of the present invention; Figures 2 to 7 are schematic representations showing a sequence of steps for covering an elongate member in accordance with the present invention.

Referring especially to Figure an encasement 1 1 4 apparatus. general ly denoted 1, has pair of parallel horizontal spaced apart conveyors 2 with a horizontal stationary rail 3 disposed therebetween. The areas adjacent the opposite end portions of the conveyors 2 have been denoted A and B, as shown in figure 1. The arrangement of the apparatus along the length of the conveyors 2 will be described starting f rom the upstream end portion A moving along to the opposite downstream end portion B. The direction from upstream A to downstream B will hereinafter be denoted direction D, as indicated in Figure 1.

A first set of pressure rollers 5, of horizontal orientation, are disposed generally above the rail 3 at the end portion A of the machine 1. A f irst heater 7 is disposed adjacent to the pressure roller at substantially the same height as the pressure rollers 5. A f olding station, generally denoted 9, is located downstream adjacent to the first heater 7. The folding station 9 includes a first folding guide 11 having a static folding face in the form preferrably of a rod. The first folding guide 11 is disposed to extend along Direction D, with its upstream end being higher than that of its opposite downstream end. The folding station 9 also includes a horizontal shielding plate 13 which is disposed below the first folding guide 11. The shielding plate 13 may be made of stainless steel. A second set of pressure rollers 15,16,17, one being vertical 15. one being horizontal 17, and one 16 being inclined, are positioned adjacent to the folding station 9; roller 16 preferably being located immediately downstream of the terminal end of guide 11. A second heater 19, a second folding guide 21, oriented similarly to the first, and a third set of pressure rollers 23 of vertical orientation are further disposed along the conveyors 2. A f ourth set of pressure rollers 25, of horizontal orientation, are further positioned along the length of the conveyors 2 adjacent to the end portion B. In operation, the apparatus 1 is supplied with a frame member, such as a door post 30 of recessed cross-section, for example the L-shaped cross- section shown in the drawings, having a longitudinally extending groove 31 in its bottom face for co-operation with rail 3. Engagement with rail 3 permits the door post to be move longitudinally but resists lateral movement caused by application of pressure by rollers on the side of the door post. The outer surf aces of the door post are coated with a dry contact adhesive. The core of the door post 30 is possibly made f rom. man-made sheet material such as medium density fibre board but can also be made from solid wood. In order to more readily describe the operation of the machine 1, the uppermost face (the face at the top of the spine of the L-shape),, the inwardly directed face depending from the uppermost face, the outwardly directed face depending from its juncture with the inwardly directed face and the junction between the inwardly and outwardly directed faces 6 shall be denoted 30(a), 30(b), 30(c) and 30(d) respectively, as indicated in Figures 2 to 6, and furthermore the term "shoulder" shall be used to refer to the surf ace formed collectively by the inwardly directed face 30(b), the junction 30(d) and the outwardly directed f ace 3 0 (c). The machine 1 is f urther provided with a sheet material 32 which has similarly been treated with a dry contact adhesive material. For a door post PVC is a preferred choice for the sheet material 32, because of its self extinguishing properties in case of fire. The contact adhesive, on both the door post 30 and the sheet 32, is selected such that the initial bonding between the two takes place when they first come into contact, the bond being completed on the application of pressure.

In use a sheet 32 is presented to the door post 30 so as to effect the adherence of a portion of the sheet 32 with the uppermost f ace of the door post 30 leaving a marginal portion 33 thereof overlying the shoulder portion of the door post 32, as depicted in Figure 2. The post 30 and sheet 32 are then presented to the machine upstream end portion A such that the groove 31 engages the rail 3. The disposition of the first set of rollers 5 above the conveyors 2 is such that the post 30 and sheet 32 are tightly engaged by the conveyors 2 and the first pressure rollers 5 and, consequentially, the movement of the conveyors in the direction D causes the post 30 to move along the rail 3. The pressure exerted by the first set of 7 rollers 5 also serves to complete the bonding of the sheet 32 with the uppermost portion 30(a) of the door post 30, as best illustrated in Figure 2.

As the post 30 is moved by the conveyors 2 in direction D it encounters a first heater 7 which serves to heat the sheet at a temperature suf f icient to render the plastics material pliable in readiness for folding. The post 30 next encounters the folding station 9. The action of the folding station is best illustrated by reference to Figures 3 and 4.

When a portion of the sheet 32 and post 30 enters the area of the folding station 9, the first folding guide 11 which has a static folding face of radius of curvature less than that of the junction 30(d) of the door post 30, urges a marginal portion 33 of the sheet 32 to bend towards the inwardly directed face 30(b). The initiation of bonding between the sheet 32 and the outwardly directed face 30(c) of the doorpost 30 is prevented by the provision of the shielding plate 13, over the surface of which the sheet may slide without bonding. The reaction between the shielding plate 13 and the inwardly directed face 30(b) serves to give positive control of the folding and provide a "tight" fold about edge 50 and progressive surface contact of the sheet material from the edge 50 to the junction 30 (d). The downstream terminal end of the guide is positioned to be closely spaced from the junction 30(d) so that the sheet 8 when emerging from the guide is pressed into the junction 30(d).

The terminal end of the folding guide 11 projects beyond the downstream edge of plate 13 to enable the guide 11 to press the sheet into the junction. In the region immediately downstream of the down stream edge of plate 13 the remainder of the marginal portion 32 is unsupported and so is also urged by guide 11 to be laid upon surface 30(c). Roller 16 is preferably located immediately downstream of guide 11 to hold and maintain pressure on the sheet to maintain contact with the junction.

Thus, on leaving the folding station 9, the sheet 32 is substantially in conformity with the inwardly directed face 30(b) and the junction 30(d), and the marginal portion 33 of the sheet 32 is permitted to contact the outwardly directed face 30(c), thereby initiating the bond therebetween. The sheet material is then held in contact with the post, whilst cooling takes place, and the bond is completed between the sheet 32 and the door post 30 using the second set of pressure rollers 15,16 and 17 as shown in Figure 5, pressure roller 15 acting on the inwardly directed face 30(b), pressure roller 16 acting into the junction portion 30(d) and the pressure roller 17 acting on the outwardly directed face 30(c). The pressure rollers 15,16 and 17 are able to apply a significant pressure to the post 30 because the post 30 is held in engagement with i 9 the rollers by the co-operation of its groove 31 with the stationary rail 3. As the post 30 is further moved by the conveyors 2 in direction D it encounters a second heater 19 which serves to render the sheet pliable for a second folding operation. Thereafter the post encounters a second folding guide 21 which operates similarly to the first folding guide 11, folds the sheet 32 on to one side of the post 30 as shown in Figure 6. The bond is then completed with the side of the post 30 using a third set of pressure rollers 23 as shown in Figure 7. The post 30 is drawn from the machine 1 using a fourth set of rollers 25, operating in a manner similar to the first set of pressure rollers 5. The relative position of the first and fourth set of rollers 5 and 25 respectively is such that at all times during the passage of the post through the machine at least one portion of the post 30 is under either set oil rollers, thereby maintaining the post 30 in pressure contact with and preventing slipping relative to the conveyors 2 so as to ensure it is positively fed through the machine 1.

The number of f olding stations is dependent on the number of f olding operations needed. In the illustrated example 2 folding stations are provided since it is envisaged that folding of marginal portion 132 may be achieved by reversing the post after emergence from the apparatus and feeding it into the apparatus with its previous trailing end now as the leading end and using the second folding station to fold marginal portion 132. To achieve this it is necessary for the side faces 60 of the profile to be the same distance d from the rail. Accordingly it may be necessary to provide a second groove 31 for reversal of the feed of the post.

However it will be appreciated that a third f olding station may be provided if desired to ef f ect f olding of marginal portion 132.

If the sheet material is foldable without the need to render it pliable by the application of heat, as for example with a wood veneer, then it will be appreciated that the heaters may be disposed with.

The above apparatus enables a shoulder to be encased wherein its junction 30(d) is of a relatively small radius. Preferably the covering sheet has a thickness less than about 3mm and preferably is in the range of 0Amm to 3mm. Preferably the radius of curvature of junction 30(d) is less than about 12mm and preferably is about 6mm.

The curvature of the guide 11 at least at the terminal end thereof which opposes the junction 30(d) and is closely spaced thereto is chosen to be about imm less than the curvature of the junction 30(d).

11

Claims

CLAIMS:

1. A process f or encasing an elongate member with an encasement formed from a single sheet of deformable material, the elongate member having a recessed prof ile defined by at least one shoulder having an inwardly directed wall and an outwardly directed wall, the process including coating the surf aces of the elongate member which are to be encased in a contact adhesive, coating one face of said sheet with contact adhesive, presenting the sheet to the elongate member so as to adhere the sheet to the elongate member with a marginal portion of the sheet overlying a shoulder on the elongate member which is to be encased, folding the marginal portion to contact the inwardly directed wall while shielding the remainder of the marginal portion from contacting the outwardly directed wall and subsequently permitting the remainder of the folded marginal portion to contact the outwardly directed wall to thereby form a continuous covering of said shoulder by said encasement.

is

2. A process according to claim 1, wherein the sheet material is formed from plastics material.

3. A process according to claim 2, wherein prior to folding, the marginal portion is heated to render the plastics material deformable.

4. A process according to claim 1, wherein the sheet 12 material is a wood veneer.

5. A process according to any preceding claim, wherein the folding of the marginal portion is achieved by longitudinally feeding the elongate member with the sheet portion bonded thereto passed folding means on the marginal portion which applies pressure which is directed inwardly of the elongate member, resistance to said pressure being achieved by guiding the elongate member along the rail means with one or more longitudinally extending grooves formed in the elongate member.

6. Apparatus for performing the method of claim 1 comprising a folding station at which the marginal portion of the sheet is folded to encase said shoulder, conveying means for conveying the elongate member longitudinally passed the folding station and guide rail means extending along the conveying means and adapted to engage with the elongate member for guiding its movement passed the folding means and provide a reaction against inwardly directed forces on the elongate member.

7. Apparatus according to claim 6, wherein a first group of pressure rollers are located upstream of the folding means and a second group of pressure rollers are located downstream of the folding means for pressing the elongate member on to the conveying means to ensure that the elongate member is positively fed passed the folding means.

13

8. Apparatus according to claim 6 or 7 wherein the elongate member has an upper f ace and a lower f ace and said shoulder extends f rom the upper f ace, said f olding means including a static folding face which has an upstream end located above said upper face and a downstream end which is located below said upper f ace at a location adjacent to the junction between said inwardly and outwardly directed walls of said shoulder.

9. Apparatus according to claim 8 wherein said junction is curved and said folding face is curved, the radius of curvature of said folding face being less than the radius of curvature of said junction.

10. Apparatus according to claim 8 or 9 wherein a pressure roller is located immediately downstream of said folding face, the pressure roller having a curved profile corresponding to said folding face and being arranged to apply pressure onto said sheet in the region of said junction.

11. Apparatus according to any claims 8 to 10 wherein a shielding means are located at said folding station to prevent the marginal portion of said sheet from said outwardly directed wall of said shoulder during folding of the marginal portion to contact the inwardly directed wall.

12. Apparatus according to claim 11 wherein the shielding 14 means comprises a plate spaced f rom the conveying means such that it lies between said outwardly directed wall and the marginal portion of the sheet, the plate having a surface to which said contact adhesive does not adhere.

13. Apparatus according to claim 12 wherein said plate is formed from stainless steel.

is

14. Apparatus according to any of claims of 8 to 13 including heating means upstream of the folding means, the heating means being arranged to heat the marginal portion prior to being fed to the folding means.

15. Apparatus for encasing an elongate member with an encasement formed from a single sheet of deformable material substantially as hereinbefore described with reference to the accompanying drawings.

16. Process for encasing an elongate member with a single sheet of deformable material substantially as hereinbefore described with reference to the accompanying drawings.

17. An elongate member having a recessed profile defined by at least one shoulder having an inwardly directed wall and an outwardly directed wall, an encasement formed from a single sheet of deformable material bonded by contact material to said walls to provide a continuous covering for said shoulder.

is

18. An elongate member according to claim 17 wherein said sheet of deformable material is a plastics material.

19. An elongate member according to claim 17 wherein said sheet of deformable material is a wood veneer.

20. An elongate member substantially as described with reference as illustrated in the accompanying drawings.

A door frame constructed from one or more elongate members according to claims 17 to 20.

22. A door frame constructed from one or more elongate members produced by the method of claims 1 to 6 or 16