GB2202163A - Spraying machine - Google Patents

Abstract

A spraying machine, e.g. for cement, comprises a hopper 11 with a pump (on shaft 13) arranged to discharge material from the hopper, a tippable mixing chamber 20 mounted above the hopper, an air compressor 30, a controllable water pump 43, a water meter 40, and a prime mover diesel motor 14 which drives the hopper, water, and air pumps and the mixing chamber, and which is controllable from a spray head at the end of a pipe attached to the hopper pump. A pipe 48 having holes produces a generally even water flow around the walls of the mixing chamber near the mouth of the mixing chamber. The mixing paddles 23 have flexible borders which in use impinge on the interior walls of the chamber, each mixing paddle comprising a metal blade having a boundary generally parallel to the interior walls of the chamber and slightly spaced therefrom, and a flexible element attached along that boundary and extending slightly beyond it. <IMAGE>

Description

SPRAYING XACIKE The present invention relates to spraying nachinery, and more specifically to machinery for spraying building materials such as cement or plastic based naterials, e.g. for application to walls as fire protective layers.

Spraying machinery of this type is well known. An example of such machinery is described in my earlier patent application, no. 2 153 797 A. That machine has a hopper portion and a mixing portion.

The hopper is shaped somewhat like a rectangular funnel with a rectangular well at its base. A worm pump is mounted at one end of the well, and is driven by a drive shaft which passes lengthwise through the well, with a coupling accessible in the well. A drive motor is mounted broadly in line with the drive shaft beyond the other end of the hopper, and is coupled to the drive shaft by belt or chain reduction gearing. The outer end of the pump has a doupling to which a pipe may be attached, the pipe having at its other end a spray head to which compressed air is also fed. A pneumatic control line passes back from the spray head to the drive motor so that the operator can control the motor.

The mixing portion is demountably mounted above the hopper, and comprises a mixing chamber which is used to mix water and cement (or whatever other materials ares being used). The mixing chamber has a horizontal shaft passing through it carrying mixing paddles or blades, and has a U-shaped section with the jaws of the U slightly pinched together in the plane perpendicular to the shaft. The shaft is driven by a motor, and passes through bushings in the end plates of the mixing chamber 60 that the chamber can be held in the upright position for mixing and then tipped over to deliver its contents into the hopper.

The general object of the present invention is to provide a spraying machine which is in certain ways more compact than this known machine, and is substantially more self-contained and more easily and accurately controllable.

The present invention also provides several improvements to various specific features of the known machine.

Accordingly the present invention provides a spraying machine comprising a hopper with a pump arranged to discharge material from the hopper, a tippable mixing chamber mounted above the hopper, an air compressor for feeding a spray head at the end of a pipe attached to the hopper pump, and a prime mover motor which drives the hopper pump, the mixing chamber, and the air pump, and is controllable from the spray head. Preferably there is also a controllable water pump and a water meter for metering the amount of water fed into the mixing chamber.

Preferably also there is a pipe having holes producing a generally even water flow around the walls of the mixing chamber near its mouth, and there are mixing paddles having resilient borders which in use impinge on the interior walls of the chamber, each paddle comprising a metal blade having a boundary generally parallel to the interior walls of the chamber and slightly spaced therefrom, and a resilient element attached along that boundary and extending slightly beyond it.

Further features of the invention relate to the control arrangements for the motor and for coupling it to the hopper pump, and to safety grilles for the mixing chamber and hopper.

Other advantageous features of the invention will be pointed out in the course of the following description of a machine embodying the invention and various modifications thereof, with reference to the drawings, in which: Figure 1 is a top view of the machine; Figure 2 is an exploded view of one of the paddles of the mixing chamber; Figure 3 shows the control mechanism for the diesel engine; Figure 3A is a top view of a detail of the control mechanism; and Figure 4 shows the safety grille for the mixing chamber.

The present machine resembles, in some respects, the prior machine mentioned above, but obviously differs in other respects. Referring to Figure 1, the machine comprises a frame 10 with a hopper 11 mounted thereon, the hopper being generally similar to the hopper of the prior machine. The hopper 11 is formed of four major sloping plates which form a funnel shape, with three further small plates forming a well 12 at its base. The well 12 and the worn pump drive shaft 13 are shown; the worn pump itself is hidden and not shown.

Optionally the shaft 13 has a coupling accessible in the well 12. The pump has a coupling at its end to which a flexible pipe (not shown) is coupled in use, with the other end of the pipe ending in a spray head at which an air supply is injected so that the operator can spray a mixture of air and the material being pumped from the hopper 11. The spray head also has a control handle which is coupled via a pneumatic control line back to the machine to control the pump in a manner described below.

Also mounted on the frame 10 is a prime mover motor 14, which is preferably a diesel engine (complete with battery, electric starter motor, and alternator and rectifier); this is mounted alongside the hopper 11 as shown.

The engine 14 has a shaft 15 which is coupled to the pump drive shaft 13 by means of an electric clutch 16 and a belt or chain coupling 17. The control line from the spray nozzle controls the clutch 16 and the speed of the engine 15, as will be described later. The motor 14, together with the. rest of the apparatus to the left of he hopper 11, is normally covered by a hinged cover (not shown), similar to that of the known machine. The frame 10 has wheels (not shown) so that it can easily be moved about and towed.

A mixing chamber 20 is mounted above the upper end (as seen in Fig. 1) of the hopper 11, and is carried on a shaft 21 by means of bushings (not shown) in the two end plates of the mixing chamber. The shaft 21 is carried by two bearings 22 fixed to the frame 10; these bearings are preferably each formed of two half bearings, so that the mixing chamber can be removed simply by unbolting the top halves of these bearings. The shaft 21 carries mixing paddles 23 for. mixing cement (or other material) and water in the mixing chamber. The shaft 15 of the engine 14 drives the shaft 21 via an electric clutch 24, a belt or chain coupling 25, a gear box 26 which changes the direction of the drive through 900, and a belt or chain coupling 27.The mixing chamber 20 has a handle 28 50 that it can be manually tipped over to deliver its contents into the hopper 11.

Alternatively, the engine 15 may have a hydraulic pump (not shown) mounted on it, and the shaft 21 of the mixing chamber 20 may be driven by means of a hydraulic motor driven from the hydraulic pump. The hydraulic coupling may incorporate a fixed offset device to keep the speed of the shaft 21 constant despite speed variations of the engine 15, or may include a control device so that the mixer speed is variable.

An air compressor 30 is mounted on the frame 10 alongside the engine 14, and driven from the shaft 15 via a belt or chain coupling 31 and a shaft 32.

The output of the compressor 30 is fed via a pipe 33 to a pressure chamber 34 which constitutes 4 high pressure reservoir. A coupling 35 is fed from the chamber 34; in use, an air pipe is coupled to the coupling 35 and leads (alongside the cement pipe from the cement pump attached to the hopper 11) to the spray head to provide the compressed air supply for spraying. A pressure gauge 36 indicates the air pressure; a pressure of about 1 XPa (10 atmospheres) has been found to produce good results. The drive from the engine 14 to the compressor 30 may incorporate an electric clutch if desired.

A control panel 40 is mounted on the frame 10, and includes a resettable water meter (not shown). A pipe 41 connects a coupling 42 to a water pump 43, driven from the engine 14 via a belt or chain coupling 44 and an electric clutch 45, and a pipe 46 connects the output of the pump 43 to the water meter in panel 40. The outlet of the water meter is connected via a pipe 47 to a water delivery system 48 in the mixing chamber 20. The pipe 47 is flexible, to allow the tipping of the mixing chamber; for clarity, only its ends 47A and 47B are shown. The clutch 45 is controlled by a switch (not shown) on the control panel 40, and this and the resettable water meter allow an accurately measured amount of water to be delivered to the mixing chamber 20. In use, a pipe is attached to the coupling 42 to connect it to a water supply such as a water tank.

As an alternative, the clutch 45 may be omitted, with the water pump pumping water continuously, and the water flow to the mixing chamber 20 being controlled by a tap. If this is done, preferably a bypass is provided, by means of a two-way tap (or a second tap) and a second coupling, so that the pump 43 runs substantially continuously, circulating water out from the water supply and back into it again nost of the time instead of running with no flow.

Another alternative is for the water pump 43 to be electric, being driven from the battery mentioned above. This of course eliminates the mechanical drive 44 and 45. A pneumatic motor driven from the air compressor 30 could of course be used instead of an electric motor.

As a further alternative, the water pump 43 and its associated drive means nay be omitted. This is feasible if the sites where the machine is expected to be used are expected to have adequate supplies of water, 60 that the provision of a pump on the machine itself becomes superfluous.

The water injection system 48 consists of a pipe of rectangular U shape which is attached inside the mixing chamber 20 near its upper edge and has a series of holes (not shown) formed at regular intervals along its underside, so that water is injected into the mixing chamber fairly uniformly along the whole length of the pipe and is directed, from each hole, downwards and outwards towards the adjacent wall of the mixing chamber. This arrangement distributes the water well for good mixing with the cement or other material being used.

It also enables the mixing chamber to be cleaned easily after use, since water can be fed into the chamber and automatically washes over and down the walls of the chamber. The pipe of course has closed ends. The mixing chamber 20 is cut away and formed as a broad spout on the lower side (as seen in Fig. 1) to ensure that when mixed material is tipped into the hopper 11, no material spills over the sides of the hopper; this cutaway helps to keep the ends of the pipe clear of the mixed material when it is being tipped into the hopper.

Fig. 2 shows the right-hand end mixing paddle 23 in detail. This paddle comprises a radial steel strip 50 welded or otherwise fixed to the shaft 21, two cross strips 51 and 52, and a second radial strip 53 as shown. The strips 52 and 53 pass close to the walls of the mixing chamber 20, but of course have a suitable clearance (say around 20 mm). This means that when material is being mixed, a layer of poorly mixed and stale material tends to build up on the walls of the mixing chamber. To prevent this, an L-shaped strip 54 (or two separate straight strips) of resilient material (plastics or rubber) is attached to the strips 52 and 53 by means of an L-shaped steel strip 55 matching the strips 52 and 53.The resilient strip 54 is sandwiched between the strips 52 and 53 and the strip 55, with nuts and bolts (not shown) passing through matching holes 56 in the various elements to hold the sandwich together. The resilient strip 54 rubs against the walls of the mixing chamber 20, preventing the build up of any surface layer of material. The strip 54 can be readily replaced when it becomes worn. The other end paddle is similar; the two intermediate paddles are also similar, but without the radial strip 53 and with straight strips corresponding to strips 54 and 55.

Fig. 3 shows the control mechanism for the diesel engine 14. The engine 14 bears a control unit 14A with a shaft 60 which is turned clockwise (as seen in Pig. 3) to increase the engine speed and power, and is internally springloaded anticlockwise to the idle position. The shaft 60 has an arm 61 fixed to it. The pneumatic control line 62 from the spray head. (not shown) is connected to a fixed cylinder 63 with a piston and piston rod 64 which terminates in a fork 65 so that when the line 62 is pressurized, the piston pushes the arm 61 clockwise.

The clockwise movement of the arm 61 is limited by the hooked end 66 & of a steel strip 66 which passes through a fixed slotted guide 67. The strip 66 has fixed to its other end a threaded shaft 68 which engages in an internally threaded cylinder 69, fixed to the end of a shaft 70 which passes through a fixed mounting 71 (which does not permit the shaft 70 to move lengthwise) to a control knob 72. Thus by turning the knob 72, the cylinder 69 is rotated and the shaft 68 and strip. 66 (which are prevented from rotating by the guide 67) are moved lengthwise, so adjusting the position of the hooked end 66A and hence limiting the clockwise movement of the arm 61. Thus the engine running speed and power obtained when the cylinder 63 is pressurized is adjustable.

The arm 61 has fixed at its upper end a crossbar 73 bent as shown in Fig.

3A, against which the arm of a switch 74 bears. A power supply 75 is connected through a safety switch 76 (mounted on the control panel 40) and the switch 74 to the clutch 16 for the worm pump drive. Thus the worm pump is de-energized when the arm 61 is in its idle position, but is energized whenever the arm 61 is turned clockwise. The switch 76 allows an operator at the machine to disaple the worm pump drive regardless of whether the operator with the spray head calls for power.

A further shaft 80 has a fork 81 which also engages the arm 61, the shaft 80 having a control knob 82 at its other end and passing through a fixed guide 83. The shaft 80 has fixed to it an arm 84 which engages with a switch 85 which controls the clutch 25 for the mixing chamber drive. Thus by pressing the knob 82 in (i.e. to the right as shown), an operator at the machine can obtain running speed and power from the engine to operate the mixer indepen dently of the control from the spray head via line 62. Of course, means for locking the shaft 80 in the inwards position may be provided. Also, of course, the limit mechanism 66 to 72 may be arranged to limit the movement of the pneumatic control means 62 to 65 rather than of the arm 61 directly, 60 that maximum power is obtainable for the mixer.

In a modification, the engine speed is controlled only by the control knob 72. In this modification, the piston 63 is coupled directly t9 the microswitch 74, and the crossbar 73 is onitted. Also, the local control rod 80 does not extend to the arm 61 and the fork 81 does not exist; instead, the rod 80 bears directly on the microswitch 85. The arrangement of the various components is of course shown only diagrammatically.

In a further modification, the clutch 16 is a pneumatic clutch. The feedback line 62 from the spray head is coupled to the clutch 16, via a pneumatic control switch in place of the microswitch 74.

Fig. 4 shows the safety grille of the mixing chamber 20. (For clarity, this is not shown in Fig. 1.) The grille 90 consists of a frame shaped to match the opening of the mixing chamber and a set of parallel bars to prevent an operator from reaching into the mixing chamber. The grille is mounted on the upper edge of the mixing chamber (as seen in the Figures) by tabs 91 fixed to the inside edge of the mixing chamber and tabs 92 fixed to the grille, with stub pivots 93 so that the grille can be opened to allow cleaning of the mixing chamber. The grille can be held in place by two bolts 94, each of which passes through holes in the frame and one bar of the grille and a corresponding hole in the end of the mixing chamber 20. Each bolt is held captive by the next bar of the grille, and has a hole 95 at its outer end so that it can be held in the locking position by a captive split pin.

The hopper 11 is also protected by a safety grille (for clarity, not shown in Fig. 1). This. grille consists of some fixed bars beneath the mixing chamber 20 and an openable portion over the exposed ed end of the hopper. The openable portion is hinged against the left-hand side of the hopper (as seen in Fig. 1) so that when it is opened, it stands upright and prevents the mixing chamber 20 from being tipped over towards the hopper 11.

The control panel 40 is preferably in fact mounted adjacent to, or to incorporate, the control knobs 72 and 82. The layout shown in Fig. 1 is, for clarity, only diagrammatic.

Claims (13)

Claims

1 A spraying machine comprising a hopper with a pump arranged to discharge material from the hopper, a tippable mixing chamber mounted above the hopper, an air compressor for feeding a spray head at the end of a pipe attached to the hopper pump, and a prime mover motor which drives the hopper pump, the mixing chamber, and the air pump, and is controllable from the spray head.

2 A spraying machine according to claim 1 further including a controllable water pump.

3 A spraying machine according to either previous claim including a water meter for metering the amount of water fed into the mixing chamber.

4 A spraying machine according to any previous claim wherein the mixing chamber includes water injection means arranged to produce a generally even water flow around the walls of the mixing chamber near its mouth.

5 A spraying machine according to claim 4 wherein the water injection means comprises a pipe mounted adjacent to the walls of the mixing chamber near its mouth and having a multiplicity of outward and downward directed holes.

6 A spraying machine according to any previous claim wherein the mixing chamber includes mixing paddles having resilient borders which in use impinge on the interior walls of the chamber.

7 A spraying machine according to claim 6 wherein each mixing paddle comprises a netal blade rigidly mounted on a central shaft and having a boundary generally parallel to the interior walls of the chamber and slightly spaced therefrom, and a resilient element attached along that boundary and extending slightly beyond it.

6 A spraying machine according to any previous claim including a clutch coupling the prime mover motor to the hopper pump and controlled by a pneumatic line from the spray head.

7 A spraying machine according to claim 6 including control means operable to override the signal from the spray head to hold the clutch disengaged.

8 A spraying machine according to either of claims 6 and 7 wherein the pneumatic line from the spray head also controls the speed of the prime mover motor.

9 A spraying machine according to any one of claims 6 to 8 wherein the clutch is electric.

10 A spraying machine according to any one of claims 6 to 8 wherein the clutch is pneumatic.

11 A spraying machine according to any previous claim including safety grilles over the hopper and the mixing chamber.

12 A spraying machine according to claim 11 wherein the safety grille over the hopper interlocks with the mixing chamber so that the mixing chamber cannot be tipped over if the safety grille over the hopper is open.

13 A spraying machine substantially as herein described with reference to the drawings.