GB2266674A - Mastics applicator guidance device - Google Patents

Abstract

The device relates to a method by which mastic, can be accurately placed around a workpiece, providing the right shape and in a set position relative to the edge of the said workpiece drawing (C5). Because the device has an adjustable guide bar it will enable an operator to place a mastic bead in any desired position while allowing "infinite" variations between the two extremes of distance provided by its design, drawing. Used with the guiding device is a nozzle that has graduations marked on its tip to assist an operator select the required size or shape of the mastic bead extruded, drawing. <IMAGE>

Description

APPLICATOR GUIDANCE DEVICE The invention relates to a guidance device, and concerns in particular a guidance mechanism for use with a mastic applicator.

Most motor manufacturers from around the world use numerous types of mastic sealers during the manufacture of car bodies, mainly for rust prevention and/or to stop water ingression to interior spaces. In general, the sealer is extruded into place, as a strip or bead, from a nozzle affixed to a suitable container, and for the most part this sealer is not visible when the car is constructed and so does not require to be decorative. However, some areas where the sealer is permanently on view can be observed around the inside of the doors, boot, tailgate, and bonnet, at the point where the steel skin is folded onto the frame (this fold is commonly termed a hemming flange).The sealer bead which provides the flexible corrosion barrier is visible when any of these access panels are opened, and because of its semi-exposed position its implementation requires an element of decorative continuity.

During the production of new panels and the eventual construction of a new vehicle, manufacturers use machinery to achieve this sealer beading. This then provides continuity of shape and position over the production cycle for many thousands of identical units. The problems of replicating this sealer beading to panels becomes evident when at a later stage of its life the vehicle suffers panel damage as a result of an accident, and the panel skin is deemed uneconomical to repair.

The task for the specialist repairer is to replace for example a damaged door skin (the outer part of the door), and duplicate as near as possible the manufacturers original pre-damaged condition of the panel, including the sealer beading.

After the old skin is removed along with the original manufacturers sealer bead a new door skin is folded over the old frame (this operation is normally achieved by hand) and after welding the skin to the frame the manufacturers specifications require that a new sealer bead is produced to provide as mentioned a corrosion-free repair and to replicate as best as possible the original sealing.

The present invention proposes a guidance device, useable with a nozzle attached mastic container, to ensure - or at least increase the chances of - the strip or bead of sealant being of neat and tidy appearance. More specifically, it suggests a nozzle guidance device which is a combination of nozzle, guide means (to maintain the position of the nozzle relative to the edge of the workpiece) and spacing arrangement by which the relative position of the guide means and thus the nozzle can be adjusted to suit different workpieces. A first embodiment employs a wheel as the guide member (different-radius wheels allowing adjustment of the spacing), and a second employs as the guide member a flatted and eccentrically-mounted bar (rotating this around its mounting enables spacing adjustment).

A third, and the presently preferred , utilizes as the guide member an eccentrically-mounted circular-section rod (also rotatable to achieve spacing adjustment), there being means (such as a tapered rod end fitting into a tapered rod-mounting socket a "morse" taper) to prevent the rod rotating except when actually required to do so.

In one aspect, therefore, the invention provides a mastic applicator guidance device, which device comprises: a nozzle, through which the sealer is to be extruded onto the surface to be coated; guide means, by which the position of the nozzle relative to the workpiece is to be maintained constant; and a spacing arrangement, by which the position of the guide means, and thus the relative position of the nozzle, can be adjusted to suit different workpieces (or different parts of the same workpiece).

I have chosen to use a commercially available nozzle but one of my own designs can be equally successful in the described devices. Because the desired shape of the sealer bead produced is best described as a rounded edged rectangle the nozzle design described takes the shape of tapered rectangle. Generally, nozzles used today for panel sealing take the form of a tapered round section, in both cases and as the guiding devices can be used with both nozzle shapes cutting the tapered section will enlarge the bead size. Any type of sealer/mastic can be used with the device in fact any substance or substances with the same or similar viscosities can be successfully used. The delivery mechanism for the described device can be by manual applicator or more generally by air assistance.

As has been noted above, the guide means can take a number of different forms. In one embodiment the method of guiding the nozzle can be by means of a wheel, shaped to run along the edge of the workpiece, and so follow the contours of the workpiece.

In practice however this does not allow for a easy way to adjust the distance from the nozzle to the edge of the workpiece: The distance can be adjusted either by employing different radius wheels or by mounting the wheel on the rod secured to the nozzle so that either the wheel can move along the rod or the rod can run in/out relative to the nozzle. In one specific embodiment of this version there is provided a collar attached to a commercially available sealer nozzle secured by a fixing nut, and from this a rod is angled to mount a guide wheel. The wheel supports the nozzle in use, and permits the operator to position the nozzle at the required distance from the panel edge to the hemming flange. This distance can be adjusted either by varying the length of the rod and or the diameter of the wheel, depending on the distance specification.

The wheel is aligned on to the edge of the panel, and the operator moves the device around the workpiece while the sealer is extruded. The wheel guides the device around the outer perimeters of the workpiece, allowing the sealer to attach itself to the panel and thus achieve a bead positioned parallel to the edge of the workpiece in the desired position.

Another way to provide the device with distance adjustment and include also a means of adjusting the diameter of the extruded sealant, is achieved by using a conveniently flatted rectangular and eccentrically-mounted guide block, rotating this around its mounting would enable spacing adjustment. Graduating the tapered rectangular nozzle tip with specific measurements enables an operator to cut the tip to the dimensional requirements.

In more detail, this second method of guiding the nozzle around a workpiece can be described as follows: There is provided a shaped nozzle that takes the form of a tapered rectangle, and incorporated into its design is a way of varying with reasonable accuracy the orifice dimensions and therefor the widths of the extruded sealant to suit the application requirements. This sealer bead dimension adjustment is achieved by including marked graduations to the nozzle tip, these graduations assist in an operator using the device to cut the escribed nozzle to the correct working angle while at the same time widen if necessary the nozzle orifice to the required size. When the device is not in use a cap is provided to help prevent the sealer from drying out.Instead of employing a wheel a better and simpler method of insuring that the nozzle follows the panel parameter can be achieved by incorporating a flatted (rectangular section) bar as the adjusting and guiding mechanism.

The bar is attached parallel to the nozzle by a collar, and can be turned to offer any one of its faces to the panel edge.

The guide bar is supported by a shaft that is attached to the end of the bar, and the shaft is eccentrically mounted into the end of the bar so that each face is a different radial distance from the shaft. Thus, when the bar is turned (through four equal 90 degree turns) it offers a different face to the workpiece and thus changes the nozzle distance to the workpiece.

In a third embodiment of the device there is used an eccentrically mounted cylindrical bar, giving "infinite" variations between the two extremes of distance.

However to ensure that this works it is necessary to provide an adequate method of locking the bar in the desired position, preventing it revolving when not required to do so. This can be achieved by using a jamming mounting for the bar on its mounting shaft (like a violin tuning peg in its socket) of the sort known as a Morse taper.

Any of the parts described can be made of any material, but I have chosen to use plastic Some specific embodiments of the invention will now be described, by way of illustration only, with reference to the accompanying Drawings in which FIG (Al) Side View, illustrates the nozzle and wheel engaged on a panel shown as dotted line L.

FIG (A2) Plan View, illustrates the same as FIG (Al) with the components of the wheel assembly, in exploded form.

FIG (B1) Plan View, illustrates the described nozzle with marked graduations, and rectangular shaped guide bar.

FIG (B2) Side View, illustrates the device set against a panel with end cap and seal.

FIG (B3) End View illustrates the guide bar principle of adjustment.

FIG (B4) End View illustrates an alternative method of guide bar adjustment using a square section bar.

FIG (C1) Side View of device attached to a sealer nozzle, identifying the basic parts illustrating the bar in the maximum and minimum positions relevant to the nozzle.

FIG (C2) Illustrates complete device with collar and guide bar attached showing tapered locking foot and peg.

FIG (C3) Illustrates the collar.

FIG (C4) Illustrates the cylindrical shaped guide bar.

FIG (C5) Illustrates a automotive door panel, as an example of the device in operation attached to a sealer gun.

FIG (C6) Illustrates a alternative angled position of guide bar, providing the most extensive range of distance variations.

Referring to the drawing FIG (Al) and (A2) the device is attached to the nozzle (2) by sliding over collar (1) and securing by nut (5). To ensure that the nozzle is correctly positioned on the panel top (P) the hemming flange as compared with wheel(4) positioned in the centre of the panel edge the distance (L) to (P) adjustment (Z) is provided, see FIG (1A). In use the device is attached to any sealer extruding device in this example an air operated unit (G). Attached to the collar is a rod (3) and this provides further attachment for the wheel sub assembly (6) in FIG (A2). This illustrates two small collars (6) shaft (8) and the wheel support bearing (7).The guide wheel (4) is set against the panel edge (L) with the sealer nose positioned at the centre point represented by line (P) (the hemming flange) where the new metal panel skin meets the frame, as mentioned, this position is varied by the manufacturers but can be accommodated by altering the length of rod (3) or by substituting a wheel (4) for a smaller or larger diameter.

The device of FIG (B1) consists of a shaped nozzle (3) that takes the form of a tapered rectangle shown as section (0). The end of the nozzle has a series of graduations (4) marked on the top and side, these are placed there to assist an operator using the device to cut the tip to the correct working angle and widen if necessary the nozzle to reproduce the desired widths of sealer required. Attached to the nozzle is a flange (9) and from this a shaft (2) extends to the rectangle guide bar (1), refer to FIG (B3), this illustrates an enlarged end section of the bar.

The guide means consists of a rectangular section bar that is able to turn through 360 degrees in 90 degree segments on the axis marked with a cross. Because the axis is off centre, if the section is turned clockwise 90 degrees,from the position shown, face (B) takes the place of face (A) and the distance (E) decreases as distance (X) is subtracted from distance (E).

Turning a further 90 degrees will bring face (C) adjacent to line (6) further decreasing the distance (E) by a factor of (Y).

When this guide bar is attached to the nozzle FIG (B1) the guide bar (1) is set against the panel edge, with the sealer nose positioned at the centre point represented by line (5),(hemming flange) where the new metal panel skin meets the frame.

The position of the nozzle is adjusted by turning the bar until the desired location is established. Line (6) represents the edge of the panel to be sealed, and is shown supporting the guide bar. The sealer gun is triggered to expel the material while at the same time rotating the device around the panel edge in a continuous motion. When the device comes to an acute change of direction the sealer trigger is released, the unit is removed, then relocated on another edge and the process repeated until the desired effect is achieved.

FIG (B2) illustrates an alternative view of the device in position on the panel (6) with sealing cap (7) and silicone sealing bellows (8). This is to provide a cap for the nozzle and help prevent premature hardening of the sealer when the device is not in use. The bellow design of seal will allow a varying size of nozzle to be accommodated in the same cap.

FIG (B4) describes an alternative square section guide bar with off-set axis. As the bar is turned it will also offer a differing face to the line (6) as the section is revolved through 4 equal 90 degree turns.This square section bar was workable but not as effective as the other example.

The device as seen in FIG (1C) consists of a mounting collar (3) that is shown attached to sealer nozzle (2), with the adjustable guide bar (1) incorporating tapered foot and peg (this example illustrates the device attached to a commercially available sealer nozzle however, the nozzle with tip graduations described previously could also be used).

The guide bar can be locked into position FIG (C2) drawing (1) and removed as shown in drawing (2) with tapered foot section (F) and peg (P) illustrated.

FIG (3C) collar. To achieve a secure fit and over come the diameter variations of the nozzle in production, and to enable the described device to be removed when necessary,incorporated into the collar bore hole are a number of rib protrusions shown, this example has three shown as (W). These moulded protrusions compress when the device is attached to the nozzle, ensuring an acceptable fit.

To this collar is fitted the cylindrical guide bar FIG (C4).

The bar has a foot section base (F) as part of its design and this is used to lock the guide bar into a corresponding tapered hole in the collar, when the desired position of the bar has been established. It is this guide bar that can be turned eccentrically through 360 degrees (however in practice only 180 degrees is necessary to obtain the distance requirements) and these variations from nozzle to workpiece are illustrated in FIG (C1) from max to min.

Because the device will be used in a semi, or completely inverted position, the tapered locking foot finally develops into a short parallel peg (P) FIG C2/C4). This peg insures that the guide bar can be lifted, turned and locked successfully in one operation.

I have found in practice that the described device can work with out using the locking foot section described, and will work using a parallel section foot. This would then rely on friction to prevent the bar from revolving, and dropping out.

Alternatively the guide bar can be mounted at an angle in the collar corresponding to the tapered nozzle as illustrated in FIG (6C), the rest of the description remaining the same. This final example provides the best distance variations from mastic bead to nozzle, irrespective of how much the nozzle is cut down to provide the required bead dimensions. Finally Production design of the guide bar as a moulding in plastic (the chosen medium) may benefit by changing the round section to a D shape, this will in practise best use the 180 degrees of movement and reduce the volume of material used by 50%.

Claims (1)

1. (1) A mastic applicator guidance device, which device comprises: a nozzle, through which the sealer is to be extruded onto the surface to be coated; guide means, by which the position of the nozzle relative to the workpiece is to be maintained constant; and a spacing arrangement, by which the position of the guide means, and thus the relative position of the nozzle, can be adjusted to suit different workpieces (or different parts of the same workpiece).

   (2) A guidance device as claimed in claim 1,wherein the nozzle design described takes the shape of tapered rectangle.

   (3) A guidance device as claimed in claim 2 wherein the tapered nozzle tip is graduated to enable specific measurements of the mastic bead and thus enables an operator to cut the tip to the dimensional requirements.

   (4) A guidance device as claimed in any of the preceding claims wherein the spacing arrangement used to control the relative position of the nozzle is a wheel, shaped to run along the edge of the workpiece, and so follows the contours of the said workpiece.

   (5) A guidance device as claimed in claim 4, wherein there is provided a collar attached to a commercially available sealer nozzle secured by a fixing nut, and from this a rod is angled to mount a guide wheel.

   (6) A guidance device as claimed in any of claims 1 to 3 wherein the spacing arrangement used to control the relative position of the nozzle is by a flatted rectangular and eccentrically mounted guide block, rotating this around its mounting will provide spacing adjustment.

   (7) A guidance device as claimed in claim 6, wherein a flattened rectangular section bar is used as the adjusting and guiding mechanism.

   (8) A guidance device as claimed in any of the claims 1 to 3, wherein the spacing arrangement used to control the relative position of the nozzle is an eccentrically mounted cylindrical bar,mounted at an angle to correspond to the angle of the nozzle used. giving "infinite" variations between the two extremes of distance provided.

   (9) A guidance device as claimed in any of claims 1 to 3, wherein the spacing arrangements used to control the relative position of the nozzle is an eccentrically mounted device that uses a tapered foot as a jamming mechanism (like a violin tuning peg in its socket) to prevent the device moving out of position when in operation on the workpiece.

   (10) A guidance device as claimed in any of the preceding claims and substantially as described hereinbefore