AU778123B2 - Improvements in or relating to mixing apparatus - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "IMPROVEMENTS IN OR RELATING TO MIXING APPARATUS" The following statement is a full description of this invention, including the best method of performing it known to me/us: "IMPROVEMENTS IN OR RELATING TO MIXING APPARATUS" This invention relates to mixing apparatus and in particular mixing apparatus including a mixing drum for mixing of particulate materials. The invention is specifically applicable to concrete mixers which may be used for mixing particulate materials inclusive of cement and sand for example.

Usually conventional concrete mixers include a mixing ooooo attachment which is adapted to be attached to a prime mover oooo 10 inclusive of skid-steer vehicles and tractors. Usually the mixing o• attachment, including the mixing drum, has an aperture at one end for loading of particulate materials into a hollow interior of the drum.

There was also included at another end of the mixing drum a drive housing including a drive motor. The skid-steer loader usually included a pair of lifting arms or booms to which were attached the mixing attachment. One method of achieving this was by the mixing attachment being provided with a pair of attachment plates which were directly attached to opposed sides of the drive housing. There was also provided a quick release coupling between each of the attachment plates and an adjacent end of an associated lifting boom.

This mixing attachment is available from Palm Manufacturing and Sales of Grove City, Minneapolis, USA.

In another conventional arrangement the skid-steer loader was provided with an attachment frame which was orientated transversely to adjacent ends of the lifting booms. The drive housing of the mixer attachment at a rear end thereof was also provided with a hitch frame which attached directly to the attachment frame of the skid-steer loader via a quick release coupling using a male-female interconnection. In this regard usually the attachment frame of the skid-steer loader was provided with an angled or bevelled top attachment frame which engaged with a corresponding shaped socket of the hitch frame and was held in place by spring loaded pins. This 10 mixing attachment is available from Hydrapower Pty Ltd in o Queensland, Australia.

The mixing drum utilised in the prior art was usually fitted with durable mixing paddles and the bowl was driven by a heavy duty sprocket or chain connected to a drive motor which was usually a hydraulic motor located in the drive housing. The drive mechanism for the bowl including the sprocket and drive motor was usually fully enclosed in the drive housing.

In operation, the mixer attachment had a plurality of hydraulic hoses which were attached to the skid-steer loader by quick release couplings.

It is an essential feature of the aforementioned mixers that they are only loaded manually by a spade or by a load hopper having a discharge chute and for this purpose the drive shaft which 4 supported the mixing drum did not extend into the hollow interior of the mixing drum. In this regard, it is mentioned in the trade literature which accompanied the HYDRAPOWER mixing attachment that the mixing drum should not be driven into a pile of sand or cement for loading purposes.

Therefore, it will be appreciated from the foregoing that loading of the mixing drum, using the conventional methods described above, is time consuming and inefficient.

It therefore is an object of the invention to provide a mixer for mixing of particulate material which may be driven into a pile of such particulate material to facilitate loading thereof.

Therefore the invention provides mixing apparatus having a mixing drum a mixing apparatus, adapted to engage with a vehicle for transport purposes, said mixing apparatus including; a mixing drum having an open front and a drive shaft which supports the drum and rotatable in unison with the drum about a longitudinal axis of the drum wherein the drive shaft extends through a hollow interior of the drum to substantially coincide with a .direction of travel of the vehicle; and said drive shaft has a free end with a plurality of support struts interconnecting the drive shaft with an inner surface of the drum.

The mixing drum preferably has an inner part that is substantially cylindrical and an outer part that has a shape resembling a truncated cone. The device shaft may have an inner end that extends through a base wall of the drum and engages with a bearing housing adjacent the base wall. Preferably the bearing housing encloses a thrust bearing adjacent the base wall of the drum and there is also provided a roller bearing adjacent the thrust bearing.

The device shaft may also be coupled to a reduction gear box of any suitable type and in one form this may comprise a sprocket drive which is coupled to a hydraulic motor.

There also may be provided an attachment frame attached to the bearing housing which may provide a means for engagement with a hitch frame of the vehicle which may be a skid-steer vehicle or front end loader.

The invention also provides a method of mixing particulate material, which includes the steps of; i) driving a vehicle having mixing apparatus attached thereto as described above into a pile of primary particulate material wherein the .•omixing drum directly contacts the pile of primary particulate material for loading of the primary particulate material into the drum through the open S. front; ii) loading secondary particulate material into the mixing drum; iii) mixing both the primary and the secondary particulate material with additional water in the mixing drum; and iv) unloading a final mix of both primary and secondary particulate material at a required location.

Preferably, the primary particulate material is sand and the secondary particulate material is cement.

Preferably after the sand has been moved to a rear part of the drum the sand is weighed.

Reference may now be made to a preferred embodiment of the invention as shown in the attached drawings wherein: FIG. 1 is a side view of a mixer of the invention in the form of a mixer component which is attached to a skid-steer loader; FIG. 2 is a more detailed view of the structure shown in FIG. 1 in regard to the specific form of attachment means between the mixer component and the skid-steer loader; FIG. 3 is a rear view of the mixer component; FIG. 4 is a sectional view through line A-A of FIG. 3; FIG. 5 is a rear view of an alternative form of mixer component; FIG. 6 is a longitudinal sectional view through the mixer component of FIG. 0 FIG. 7 shows a view of the mixer apparatus of the invention excavating a pile of particulate material; FIG. 8 shows a similar view to FIG. 7 with the mixer o o oO° °o apparatus withdrawing from the file with the particulate material contained in the mixing drum; FIG. 9 shows a similar view to FIG. 7 with the mixing drum being elevated to unload the particulate material.

FIG. 10 shows a different drive assembly to that shown in FIG. 4; and FIG. 11 shows a range of various shapes that can be adopted in relation to the mixing drum.

ooooo In the drawings there is shown skid-steer loader having a cabin 11, ground engaging wheels 12, roof 13 and chassis 14. The skid-steer loader 10 includes a pair of upper booms or lifting arms 15, support arms 16 and hydraulic lift cylinders 17, having ooooo ~piston rods 18. There is also provided a pair of pivot joints 19 and lower lifting arms 20 which are each pivotally attached to pivot joints 19. There is also provided a pair of dump hydraulic cylinders 21 which are each pivotally attached to each lifting arm 20 at 22. Piston S•rods 18 are each pivotally attached to pivot joints 19 at 23. There is also provided a hitch frame 24 which is pivotally attached to each lower lifting arm 20 at 25 and to piston rod 26 of each dump cylinder 21 at 27. There are also provided fluid hoses 28 of skid-steer loader which may be coupled to hydraulic hoses 29 of bucket assembly by quick release couplings 31. Hoses 28 attach to flange 32A of connector 32.

It will also be appreciated that each lifting arm 15 is pivotally attached to cabin 11 at 33 and each lift cylinder is pivotally attached to cabin 11 at 34.

There is also provided mixing drum or bowl 35 which includes a base or inner part 36 of cylindrical shape.and a tapered or truncated part 37. The hitch frame 24 is provided with support 24A of each lifting arm 20 and is attached to support bracket 20A of attachment frame 38 wherein wedge shaped end 208 of hitch frame S•24 is retained within socket 20C of attachment frame 38 formed by L 10 shaped members 20D orientated as shown. Spring loaded ~attachment pins (not shown) fasten hitch frame 24 to attachment frame 38. There is also shown bearing housing 40 and sprocket .ooeoi pulley 48 which support a drive shaft 42 shown in FIGS. 3-4.

In FIGS. 3-4 there is also illustrated a hydraulic motor 43 having an output shaft 44 which engages with pulley 45 at bore 46.

Motor 43 is mounted on mounting plate 43A. There is also provided eoooo sprocket or chain 47 which engages with sprocket pulley 48 to drive rotation of shaft 42. In bearing housing 40 there are provided thrust bearings 48A and roller bearings 49. Associated with hydraulic motor 43 are relief valve 50, hydraulic conduits 51, support member 52 for conduits 51 and flow control valve 53 for attachment of hoses 29.

In attachment of shaft 42 to drum 35, there are also provided mounting collar 54 having attachment flange 55 and locating 8 collar 56 of drum 35. Attachment frame 38 is attached to base part of bearing housing Drive shaft 42 extends into the hollow interior of mixing drum 35 and is provided with radial support arms 57 which are each connected to shaft 42 at 58. Each of arms 57 also are attached to wear plates 59 which reinforce side wall 60 of mixing drum 35. Each of wear plates 59 comprise bands 60A oriented side by side.

An alternative embodiment of the drive train or drive ooooo S•mechanism for rotation of mixing drum 35 is shown in FIGS. 5-6 wherein the drive shaft 42A is retained within thrust bearings 61 and two sets of roller bearings 62 and sprocket 63 is mounted rearwardly of bearings 61 and roller bearings 62. Sprocket 63 engages with oooo° sprocket pulley 64 and also with pulley 65 mounted to output shaft 66 of hydraulic motor 67. There is also provided hydraulic fluid conduits 68, connectors 69 and support member 70. In this arrangement the attachment flange 70 is attached directly to flange ooooo S"72 of motor 67 and also to base part 73 of bearing housing 74 which is omitted from FIG. 6.

In FIGS. 7-9 there is shown a sequence of operations illustrating the method of the invention which may include the following steps: driving skid-steer loader 10 and attached mixing drum 35 into a pile of particulate material such as sand, as shown in FIG. 7. In this step the mixing drum is preferably kept stationary.

Preferably the mixing drum is elevated by activation of dump cylinders 21 and rotated to remove the sand to the rear of the drum This procedure may be repeated 2-3 times. When this step has been completed, the sand may be weighed by weighing means such as a load cell or sensor, normally associated with lift cylinders This may be done by measuring the hydraulic pressure in the lift arm circuit as the load is lifted past the sensor. The pressure reading may •be converted to pounds or kilograms and displayed visually to the operator; (ii) the skid-steer loader may then lift up the required amount of sand as shown in FIG. 8 before moving to another site for o••e• loading of cement. This may be done manually using 1-2 bags or as many bags as may be required. Alternatively the cement may be loaded into drum 35 by other means such as a loading hopper wherein cement from a silo is loaded into the drum through a loading •chute; and (iii) after the mixing drum 35 is provided with the appropriate amount of sand and cement and mixed with water, the final mix 76 may be discharged onto the required location of a building site as shown in FIG. 9.

In a variation of the foregoing, the thrust bearings may be dispensed with an use may be made of two tapered roller bearings within housing 40 or 74.

It will also be appreciated that the invention also includes a method of loading particulate material as described above in relation to FIGS. 7-9.

Reference may be made to another embodiment shown in FIG. 10 which is an alternative drive assembly to that shown in FIG. 4. In FIG. 10 there is provided hydraulic motor 80, knuckled nut 81 attached by split pin 82 to shaft 42, opposed wear plates 83, bearing housing 84 and grease nipples 85. Other reference numerals are shown to identify similar components as shown in FIG. 4. This drive assembly is durable but will require constant application of lubricating grease to grease nipples FIG. 11 shows various shapes that may be adopted in relation to mixing drum The invention also provides a mixing drum per se having a drive shaft extending into the interior thereof and connected to the internal side wall by support struts or other suitable attachment means.

Advantages of the invention include the following: developing an effective loading procedure which can be carried out without effort and in relatively quick time such as 5-10 minutes compared to prior art methods of 15-20 minutes; and (ii) use of a much larger capacity mixing drum capable 11 of handling loads of 800-1000 litres rather than prior art methods of 125 150 litres.

From the advantages and (ii) above it will be appreciated that the invention provides a much less time consuming, more efficient and more economical method of loading particulate materials.

Claims (9)

1. A mixing apparatus, adapted to engage with a vehicle for transport purposes, said mixing apparatus including; a mixing drum having an open front and a drive shaft which supports the drum and rotatable in unison with the drum about a longitudinal axis of the drum wherein the drive shaft extends through a hollow interior of the drum to substantially coincide with a direction of travel of the vehicle; and said drive shaft has a free end with a plurality of support struts interconnecting the drive shaft with an inner surface of the drum.

2. Mixing apparatus as claimed in claim 1 having an inner part that is substantially cylindrical and an outer part that has a shape resembling a truncated core.

3. Mixing apparatus as claimed in claim 1 or 2 wherein the drive shaft has an inner end that extends through a base wall of the drum and engages with a bearing housing adjacent the base wall.

4. Mixing apparatus as claimed in claim 3 having an attachment frame for engagement with a hitch frame of the vehicle, said 20 attachment frame being attached to the bearing housing.

5. Mixing apparatus, substantially as herein described, with le: reference to FIGS. 1-6, 10 and 11 of the accompanying drawings.

6. A method of mixing particulate material, which includes the step of: 13 i) driving a vehicle having mixing apparatus attached thereto as claimed in claim 1 into a pile of primary particulate material wherein the mixing drum directly contacts the pile of primary particulate material for loading of the primary particulate material into the drum through the open front; ii) loading secondary particulate material into the mixing drum; iii) mixing both the primary and the secondary particulate material with additional water in the mixing drum; and iv) unloading a final mix of both primary and secondary particulate material at a required location.

7. A method as claimed in claim 3 wherein the primary particulate material is sand and the secondary particulate material is cement.

8. A method as claimed in claim 7, wherein after the sand has been moved to a rear part of the drum the sand is weighed.

9. A method of mixing particulate material as herein described with reference to FIGS. 7-9 of the accompanying drawings. oooo *go *oooo *oo