GB2311800A

GB2311800A - Plastering apparatus

Info

Publication number: GB2311800A
Application number: GB9607058A
Authority: GB
Inventors: Stephen Mcdermott
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-04-03
Filing date: 1996-04-03
Publication date: 1997-10-08
Anticipated expiration: 2016-04-03
Also published as: GB2311800B; GB9607058D0

Abstract

An apparatus 10 for applying plaster to a wall comprises a frame 12, for erection adjacent to the wall, and a spray gun 70. The gun 70 is moved within the frame 12 vertically and horizontally by first and second carriage 30, 60 respectively. The gun 70 is mounted on the second carriage 60. Drive means for the vertically movable first carriage 30 may be provided by a first motor 20 and belts (or chains) 23, 29. The horizontally movable second carriage 60 is driven by a second motor 65 mounted thereon. Automatic control of the movement of the carriages 30, 60 may be provided a thyristor D.C. control unit (not shown) and sensors (figures 3, 6) provided to sense the position of the carriages 30, 60 within the frame 12. Limit switches may be used as alternatives to the sensors. A vertically movable finishing tool (not shown) may be attached to the first carriage 30. Plaster may be applied to a wall by incremental steps of carriage 30 in a vertical direction each such step being executed following a horizontal motion of carriage 60.

Description

PLASTERING APPARATUS DESCRIPTION This invention relates to plastering apparatus.

Background to the Invention It is known, particularly in Germany, to provide plastering apparatus in the form of a hand-held spray gun supplied via a flexible delivery tube with plaster of a low viscosity and substantially "runny" consistency and derived from a source where the dry plaster is mixed with water. Such apparatus has not been widely accepted in the United Kingdom because the use of a hand-held spray gun makes it difficult to ensure an even coating whilst spraying, and furthermore because of the ongoing need for the presence of a skilled plasterer to effect ruling and finishing of the gun-applied plaster - which ruling and finishing must still be performed manually - even if the spraying operative was not a skilled plasterer.

It is therefore considered advisable to provide plastering apparatus which can overcome these and/or other disadvantages of the prior art.

Brief Description of the Invention According to a first aspect of this invention there is provided plastering apparatus comprising: frame means for erection beside a wall to be plastered, a plaster spray gun, and means mounting the gun for controlled movement with respect to the frame means.

Preferably said movement is controlled automatically by drive means controlled by limit switches or proximity sensors associated with the frame means.

Advantageously said movement comprises incremental steps in a generally vertical direction relative to the frame means, each such step being executed following a generally horizontal motion from substantially side to side of the frame means.

Preferably, in use, the plaster spray gun is operated to spray plaster during each said generally horizontal motion of the gun (which motion may be reciprocal), but not spray plaster whilst the said incremental steps are being executed. Advantageously, automatic control means are provided to effect this combined operation of plaster spraying and gun motion.

According to a second aspect of this invention there is provided plastering apparatus comprising: frame means for erection beside a wall to be plastered, first carriage means to be mounted on the frame means for vertical motion with respect thereto, first motion imparting means to move the first carriage means vertically in incremental steps, second carriage means to be mounted on the first carriage means for linear motion horizontally with respect to the first carriage means, second motion imparting means to move the second carriage means linearly (preferably reciprocally) with respect to the first carriage means, and a plaster spray gun for mounting on the second carriage means to spray plaster onto the wall during said linear motion of the second carriage means.

Preferably, with either said aspect of the invention, the apparatus comprises ruler means mounted (e.g. on the first carriage means) for movement in a vertical direction to rule and finish the plaster applied by the spray gun onto the wall.

Brief Description of the Drawings By way of example one embodiment of apparatus according to this invention will now be described with reference to the accompanying drawings of which: Figure 1 is a schematic rear elevation of the embodiment of apparatus according to this invention, Figure 2 is an enlarged side view of part of the apparatus of Fig 1, Figure 3 is an enlarged rear elevation of part of the apparatus of Fig 1, Figure 4 is a cross-sectional view on the line IV-IV of Fig 3, Figure 5 is a cross-sectional view on the line V-V of Fig 4, and Figure 6 is a schematic side view showing parts of the apparatus omitted from Fig 4.

The illustrated plastering apparatus 10 is erected adjacent the face of a wall 11 to be plastered. It comprises a framework 12 (Fig 1) composed of a pair of side frames 13 and 14, e.g. approximately 2.35m high, connected at their upper ends by a rotatable connecting shaft 15, e.g.

approximately 1.75m long, and by a stretcher rod 17 (Figs 3 and 4). Each side frame 13,14 has the general form of a floor-mounted right-angle triangle (Fig.2) with its "hypotenuse" constituted by a bracing strut 16 connected between the vertical upright 18 - which extends upwardly beyond the upper end of strut 16 - and the horizontal base 19, which for example is approximately 0.7m long.

The side frame 14 has an electric drive motor unit 20 mounted thereon and coupled via an endless chain or belt 21 to one wheel of a double sprocket wheel or pulley 22. The motor unit 20 may have 95 watts (1/8 HP) output, and preferably is operated via a thyristor D.C. controller and incorporates an output spur gear providing an output speed of 28 rpm. The motor unit 20 may also be associated with an inductive sensor to provide a predetermined number of pulse signals (e.g. 6) per revolution. The other wheel of the double sprocket or pulley 22 is connected via a chain or belt 23 to a sprocket wheel or pulley 24 at or adjacent one end of the upper connecting rod 15. A matching pair of sprocket wheels or pulleys 26,28 and chain or belt 29 act between the other end of connecting rod 15 and the bottom of the other side frame 13.

A horizontal carriage 30 is attached by its ends to the two belts 23,29 so as to be movable vertically, in an incremental fashion, as the motor unit 20 is energised. As best shown in Figs 3 and 4, such attachment is by a screwadjuster device 31 that is provided at each end of the carriage 30. Guide means are provided to ensure that the horizontal carriage 30 is guided during its incremental vertical motion. For this, the inwardly directed surface of each side frame's upright 18 is provided with a vertically extending guide track 33,34 (Figs 5 and 6). Guide track 34 on side frame 14 has an outwardly pointing V-shaped periphery for mating co-operation with upper and lower pairs of V-grooved guide rollers 36,38. Guide track 33 on the opposite side frame 13 is flat-faced (rather than Vshaped) and is engaged by upper and lower pairs of cylindrically-surfaced guide rollers 37,39 (Fig 6). This permits free vertical movement of the carriage 30 without "binding up" due to horizontal spacing anomalies and/or tolerances.

Each end of the carriage 30 has a side plate 40 mounted adjustably thereon by an adjustment mechanism 41 and such that the side plates 40 extend forwardly of the carriage 30 (see Figs 4 and 5). The adjustment mechanism 41 comprises a pivot pin defined by a screw or bolt 42, and an arcuate slot 44 (centred on the axis of the pivot 42) in the plate 40 and through which a clamping screw or bolt 43 is fastened. The angular position of the side plates 40 can thus be adjusted relative to the carriage 30. A bracket member 46 is adjustably mounted to the free end of each side plate 40 by a similar adjustment mechanism 45 comprising a pivot pin (provided by a bolt 47), an arcuate slot 48 (centred on the axis of pivot 47) in bracket 46, and a clamping screw or bolt 49. A stainless steel scraper bar 50 is fixed to the two bracket members 46 to extend between them, the angle and position of the scraper bar 50 in relation to the wall 11 to be plastered being capable of adjustment by one or both of the adjustment mechanisms 41 and/or 45.

The main beam 52 of the vertically movable carriage 30 carries a horizontal rail 54 on its rearward surface, this rail 54 having its upper and lower edges of outwardly projecting V-shaped form. The main beam's rearward surface also carries an elongate support bar 56 formed at its distal edge with a horizontally extending rack 55 having its teeth directed downwardly (see also Fig 6). Another carriage 60 is provided with upper and lower pairs of Vgrooved guide wheels 64 that are mounted on the upper and lower V-shaped edges of the horizontal guide rail 54 to render carriage 60 horizontally movable with respect to the vertically movable carriage 30. The horizontally movable carriage 60 has an electric motor 65 mounted thereon, the motor driving a spur gear 66 in mesh with the downwardly directed teeth or rack 55. By providing the horizontally extending rack 55 with its teeth directed downwardly (in mesh with the spur gear 66), the risk is minimised of the gearing becoming fouled and inoperative due to falling plaster splashes arising from plastering of wall 11.

A plaster spray gun 70 is attached to the horizontally movable carriage 60 by means of a C-clamp 68 provided at the free end of an extension arm 69 that is attached to the lower end of carriage 60. The plaster spray gun 70 may be of known type (e.g. a Model G4 obtainable from Putz- und Fördertechnik GmbH, Iphofen, Germany) and supplied via a flexible delivery tube 72 with plaster of a low viscosity and substantially "runny" consistency from a plaster source (not shown) where the dry plaster is mixed with water.

It will be appreciated that the travelling motor 65 controls its own linear motion along the horizontal track with that of the horizontally movable carriage 60 and the plaster spray gun 70 attached thereto.

A plurality of proximity sensors, including those referenced generally 75-77 in the drawings, are provided to sense the positions of the two carriages 30,60 relative to one another and to the side frames 13,14. The proximity sensors 75-77 are connected to an electrical control unit to control operation of the motors 20,65. The control unit also controls operation of the spray gun 70, to switch it ON and OFF, via a solenoid-operated air valve.

With the illustrated plastering apparatus 10 erected across the face of a wall 11 to be plastered, the following set-up procedures are adopted: - The plastering gun 70 is clamped in clamp 68 and positioned an appropriate distance from wall 11; - The position of the scraper blade 50 is set using the adjustment mechanism(s) 41 and/or 45; - The carriage 30 is positioned at its lowermost level with regard to the side frames 13 and 14; and - The carriage 60 is positioned at the left-hand corner, i.e. adjacent side frame 13.

In these positions a lowermost proximity sensor 76 (Fig 6) and a leftwards proximity sensor 77 are activated. A main switch of the control unit is then operated to energise the solenoid-valve-controlled air supply to the gun (whereby the gun 70 starts to spray plaster at the wall) and to initiate operation of motor 65 such that it drives carriage 60 horizontally from left to right along stationary carriage 30 and towards side frame 14. A strip of plaster is thus applied to the wall 11.

When the carriage 60 reaches (or approaches) side frame 14, its position is sensed by a right-hand-end sensor (like 77) and, as a result, the control unit stops the motor 65, closes off the air supply that operates the spray gun 70, and initiates operation of motor 20 such as to raise the carriage 30. The distance raised, which may be of the order of 40mm, is set by the signal from the inductive sensor associated with motor unit 20 (provided, in this example, by 1/6 of a revolution of the output spur gear of motor unit 20). As the carriage 30 is raised the strip of plaster is "ruled" by scraper bar 50.

The control unit operates such as to stop motor 20 in response to the signal from the motor-associated inductive sensor, and then to initiate operation of the horizontal drive motor 65 (in the opposite direction) and again switch to ON the solenoid-operated air valve controlling air supply to the spray gun 70 whereby it re-commences ejecting plaster against the wall.

When the carriage 60 (driven by motor 65) reaches or approaches left-hand side frame 13, a left-hand proximity sensor 76 (Fig 6) signals the control unit to stop motion of carriage 60, switch off the solenoid-operated valve suppling air to the spray gun 70, and initiate motor unit 20 (in the same direction as before) to raise carriage 30 by a similar increment.

The cycle of operations continues and it will be appreciated that plaster is applied to wall 11 in successive strips as the spray gun passes reciprocally along carriage 30, and that such successive strips of plaster are smoothed to a uniform substantially planar rendering of the wall by the scraper bar 50 passing across those strips as the carriage 30 is indexed upwardly by similar increments by successive activations of motor unit 20.

An uppermost sensor 75 (Figs 3,5) senses the approach of carriage 30 to its upper limit (towards the top of the extended uprights 18 of side frames 13,14) to cause the control unit to stop the sequence of operations. The scraper blade 50 can then be removed (and, if need be, cleaned) and a return switch actuated to return carriage 30 to its lowermost start position.

Advantageously the control unit includes an emergency switch which, when operated, stops both motors 20,65 and operates the solenoid valve to shut off the air supply to the spray gun 70.

It will be appreciated that, since the scraper bar 50 follows on, automatically, within a very short time duration after application of the plaster by the gun, little or no time is allowed for the brick wall 11 to apply suction to the plaster and overly dry it out. In other words the applied plaster is still substantially wet and "runny" during ruling by the scraper bar 50 and hence very little pressure needs to be applied by the apparatus and its scraper bar 50 to achieve a smooth finish.

Furthermore, for situations where there is no top and bottom "ground" for the plaster, the spray gun 70 may be provided with a swan-neck or other swivel outlet able to direct the plaster to the uppermost and lowermost zones of the wall that would not otherwise be covered by plaster with the gun 70 in its normal spraying position as used for the major area of the wall 11.

Optionally, the apparatus may be provided with sensors responsive to the outline of the wall, e.g. recesses, projections, windows, doorways and the like, to modify the usual linear motion and/or the usual continued spraying of the gun 70.

It will also be appreciated that instead of proximity sensors 75-77 the control unit could respond to the actuation of limit switches positioned appropriately on the framework for physical actuation by the carriages 30,60.

However, proximity sensors are preferred as they are less liable to malfunction in the event that globules of plaster fall on them.

Other modifications and embodiments of the invention will be readily apparent to those skilled in this art, and all such modifications and embodiments are to be deemed within the ambit and scope of the invention. Thus the invention is not to be deemed limited to the particular embodiment(s) hereinbefore described and such may be varied in construction and detail without departing from the scope of the patent monopoly hereby sought.

Claims

1. Plastering apparatus comprising: frame means for erection beside a wall to be plastered, a plaster spray gun, and means for mounting the gun for controlled movement with respect to the frame means.

2. Plastering apparatus according to Claim 1 comprising drive means controlled by limit switches or proximity sensors associated with the frame means to control said movement automatically.

3. Plastering apparatus according to Claim 1 or Claim 2, wherein said movement comprises incremental steps in a generally vertical direction relative to the frame means, each such step being executed following a generally horizontal motion from substantially side to side of the frame means.

4. Plastering apparatus according to Claim 3 wherein said generally horizontal motion is reciprocal.

5. Plastering apparatus according to Claim 3 or Claim 4 wherein, in use, the plaster spray gun is operated to spray plaster during each said generally horizontal motion of the gun, but not spray plaster whilst the said incremental steps are being executed.

5. Plastering apparatus according to Claim 4 comprising automatic control means to effect, in combination with one another, the operations of plaster spraying and gun motion.

6. Plastering apparatus comprising: frame means for erection beside a wall to be plastered, first carriage means to be mounted on the frame means for vertical motion with respect thereto, first motion imparting means to move the first carriage means vertically in incremental steps, second carriage means to be mounted on the first carriage means for linear motion horizontally with respect to the first carriage means, second motion imparting means to move the second carriage means linearly (preferably reciprocally) with respect to the first carriage means, and a plaster spray gun for mounting on the second carriage means to spray plaster onto the wall during said linear motion of the second carriage means.

7. Plastering apparatus according to Claim 6, wherein said second motion imparting means is arranged to move the second carriage means reciprocally with respect to the first carriage means.

8. Plastering apparatus according to any one of Claims 1 to 7, wherein the apparatus comprises ruler means mounted for movement in a vertical direction to rule and finish the plaster applied by the spray gun onto the wall.

9. Plastering apparatus according to Claim 8 when dependent from Claim 6, wherein said ruler means is mounted on the first carriage means.

10. Plastering apparatus substantially as herein described with reference to and/or as illustrated in the accompanying drawings.

Amendments to the claims have been filed as follows 1. Plastering apparatus comprising: frame means for erection beside a wall to be plastered, a plaster spray gun, means for mounting the gun for movement with respect to the frame means, and drive means to effect automatic controlled movement of the spray gun with respect to the frame means.

2. Plastering apparatus according to Claim 1 comprising limit switches or proximity sensors associated with the frame means to effect said automatic control.

6. Plastering apparatus according to Claim 5, comprising automatic control means to effect, in combination with one another, the operations of plaster spraying and gun motion.

7. Plastering apparatus comprising: frame means for erection beside a wall to be plastered, first carriage means to be mounted on the frame means for vertical motion with respect thereto, first motion imparting means to move the first carriage means vertically in incremental steps, second carriage means to be mounted on the first carriage means for linear motion horizontally with respect to the first carriage means, second motion imparting means to move the second carriage means linearly (preferably reciprocally) with respect to the first carriage means, and a plaster spray gun for mounting on the second carriage means to spray plaster onto the wall during said linear motion of the second carriage means.

8. Plastering apparatus according to Claim 7, wherein said second motion imparting means is arranged to move the second carriage means reciprocally with respect to the first carriage means.

9. Plastering apparatus according to any one of Claims 1 to 8, wherein the apparatus comprises ruler means mounted for movement in a vertical direction to rule and finish the plaster applied by the spray gun onto the wall.

10. Plastering apparatus according to Claim 9 when dependent from Claim 7, wherein said ruler means is mounted on the first carriage means.

11. Plastering apparatus substantially as herein described with reference to and/or as illustrated in the accompanying drawings.