NZ260282A - Moulding apparatus with tamping head over mould table, the latter being raised and locked by hydraulic intensification - Google Patents

Description

1\MZ -5*0 PATENTS FORM NO. 5 Fee No. 4: $260.00 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 260282 BatedLHAprtross ao Wvv+ MOULDING APPARATUS fc n r 16 AUG 1995 [...

I/WE Marsden Machinery Limited, a New Zealand company of Corbett Road (no street number), Bell Block, New Plymouth, New Zealand hereby declare the invention for which I/We pray that a patent may be granted to -me/us, and the method by which it is to be performed to be particularly described in and by the following statement: 1 1 260 28 2 Moulding Apparatus technical field This invention relates to methods and apparatus for the manufacture of mouldable products, and has particular application to the manufacture of concrete products such as paving stones, blocks, paving slabs and the like. background ART New Zealand Patent No. 189115 describes an apparatus for moulding articles such as concrete pavers, blocks and slabs. Since the lodgement of New Zealand Patent No. 189115 the need has arisen for more automated processing and precision from individual machines.

It is an object of the present invention to provide an improved method of manufacture of moulded products and an apparatus for carrying out the method.

Further objects and advantages of the present invention will become apparent from the ensuing description which is given by way of example.

Disclosure of invention According to the present invention there is provided apparatus for the manufacture of moulded products comprising a frame, a tamping head supported by the frame, a mould table beneath the tamping head said mould table being adapted to receive and support a product mould, 26 0 28 2 means for reciprocating the tamping head towards the mould table, means for raising the mould table, and vibration means for vibrating the mould table comprising a plurality of selectively positioned impact vibrators each having impact shafts arranged to repetitively impact on the mould table at high speed to vibrate same.

The mould table can be supported independently of the frame and the vibrators impact directly on the table surface.

The mould table can be supported by a pair of hydraulic cylinders.

The means for raising the mould table comprises a pair of hydraulic cylinders, a reservoir of pressurised fluid communicable with the hydraulic cylinders and a control valve positioned between the reservoir and the hydraulic cylinders said control valve having a piston therein which controls the supply of fluid to the hydraulic cylinders to extend same, and then by further movement intensifies the pressure within each cylinder to lock the mould table in & moulding position.

The control value may comprise cylinder body having a piston chamber, an outlet chamber separate outlets to the hydraulic cylinders from said outlet chamber, a piston within said piston chamber said piston having a first piston shaft which extends from the piston in one direction and a second piston shaft which extends into the outlet chamber in the opposite direction, the piston being capable of advancing and retracting within the piston chamber, and said outlet chamber and the second piston shaft having complimentary first and second sections, said second sections being of reduced cross—sectional area, the outlets from the piston 3 260 28 2 chamber being communicable with respective hydraulic cylinders, the arrangement being such that with the control valve in an open position pressurised liquid can pass freely into the hydraulic cylinders and on further advancement of the piston the second piston forces a residual of fluid from said first and second outlet chambers to said hydraulic cylinders further increasing pressure in each of the cylinders.

The first and second outlet chambers can be of equal volume.

Sealing means may be provided between the inner walls of the first and second sections of the outlet chamber and the first section of the piston and the second section of the piston.

Means can be provided for advancing the piston within the control valve by an allowable increment once the mould table is extended into its raised position.

Brief Description of Drawings « Further aspects and advantages of the present invention will become apparent from the following description which is given by way of example with reference to the accompanying drawings in which:- Figure 1: is a side view of one form of apparatus in accordance with the present invention, and Figure 2 & 3: are end views of apparatus in accordance with the present invention, and Figure 4: is a schematic diagram of an arrangement for lifting and locking the mould table in accordance with one aspect of the present invention, and 2 60 282 Figure 4a: Figure 5 & 5a: Figure 6: Figure 7 & 8: Figure 9: Figure 10: is an enlarged cross-sectional drawing of a portion of the control value of figure 4, and. are plan and cross-sectional views of a mould table and vibrator arrangement in accordance with a further aspect of the present invention, and is a diagrammatic cross-sectional drawing of a pressure intensifier at the tamping head of apparatus in accordance with the present invention, and are schematic diagrams of possible alternative arrangements for the control of the tamping head and mould table of the present invention, and is a an exploded view of an impact vibrator in accordance with one possible embodiment of the present invention. is a flow diagram showing preferred control sequences for apparatus of the present invention.

Best Modes for Carrying out the t Cl'JOfClf.YCOC Firstly with respect to figures 1 to 3 of the drawings apparatus in accordance with the present invention will typically comprise a frame generally indicated by arrow 1, an overhead hopper 2, means such as a double-acting piston 3 for opening the hopper 2 a drawer 4 which is essentially an open bottomed tray which delivers a mouldable material such as a concrete or other cementations material to a mould 5 beneath a tamping head generally indicated by arrow 6. During the moulding of a product the mould 5 is supported by the frame. 260 282 The tamping head 6, comprises a rigid cross-member 8 which supports a plurality of tamping members 9 which are configured to correspond with opening(s) (not shown) in the mould 5 below. Guides 10 ensure accurate reciprocation of the tamping head which is driven up and down by hydraulic cylinders 11,12 described in further detail later.

The mould 5 is supported by hydraulic cylinders 13. The openings in the mould are shaped to provide the required product, for example bricks, paving stones or the like and vary in shape and depth accordingly. Apparatus such as described are now well known as in the mode of operation of same.

To manufacture product the drawer 4 is loaded with a predetermined quantity of mix from hopper 2, and advanced over the mould 5 where it deposits in opening(s) in the mould 5. The drawer 4 is withdrawn and the tamping head 6 lowers onto the mould and the tamping members 9 enter corresponding openings in the mould(s) and compact the deposited mix whilst the mould(s) table and therefor the mould on it is vibrated. The mould 5 is then lowered and moulded product on it removed. A control console 14 (figure 2) can be mounted actfacent the mould head.

Figures 2 and 3 illustrate slightly different configurations with the arrangement for driving the larger tamping head of figure 3 being described in more detail later.

In the figure 2 embodiment the centre cylinder 12 lifts the tamping head 6 and the larger cylinders 10 push.

As can be imagined there are large downward forces generated during the operation the tamping head which must be resisted byr-the mould table.

N.Z. PATENT OFFK and because the apparatus is readily mechanis id an eMcient 17 NOV 1997 260 282 vibration system will lessen the time at which opposed forces impact on one another.

Figures 4, and 4a and Figure 8 of the drawings herewith illustrate aspects of the present invention and the methodology involved for raising of the mould table and securing it in position during the moulding process.

With respect to figures 4 and 4a mould table 7 is raised by hydraulic cylinders 13 which receive fluid under pressure from a reservoir 15 via a control valve generally indicated by arrow 16. Joth figures 4 and 4a are generally diagrammatic to assist the understanding of this aspect of the apparatus.

The control valve 16 comprises a cylinder body 17 having a piston chamber 18, an outlet chamber 19, separate outlets 20, 21 to the hydraulic cylinders 13 from said outlet chamber, a piston generally indicated by arrow 22 within said piston chamber 18 said piston 22 having a first piston shaft 23 which extends from the piston in one direction and a second piston shaft 24 which extends into the outlet chamber 19 in the opposite direction, the piston 22 being capable of advancing and retracting within the piston chamber, an'' said outlet chamber 19 and the second piston shaft 24 having complimentary first and second sections 25, 26, said second section 26 being of reduced cross—sectional area, the outlets 20, 21 from the piston chamber being communicable with respective hydraulic cylinders 13. With the control valve 16 in an open position see figure 4a pressurised liquid can pass freely into the hydraulic cylinders 13 and on further advancement of the piston 22 the second piston section 26 forces a residual of fluid from said first and second outlet chambers to said hydraulic cylinders 13 further increasing £60282 pressure in each of the cylinders.

The first and second outlet chambers 27, 28 respectively are of equal volume.

Sealing means 29 are provided between the inner walls of the first and second sections 27, 28 of the outlet chamber and the piston 22.

Means such as a double acting cylinder (not shown) are provided for advancing the piston 22 within the control valve by an allowable increment once the mould table 7 is extended into its raised position.

It will be appreciated that the final incremental movement of the of valve 16 in the arrangement illustrated isolates the pistons 13 from the pressure system and each other so that each end of the table 7 is provided with independent means of support. This eliminates "rocking" of the table which may otherwise occur if the cylinders 13 are not isolated from the pressure system.

With respect to figures 5 and 5a of the drawings the mould table 7 in trough-like and has end portion 31 recessed to accommodate its disposition between frame members 32. Cylinders 13 support the table and the table is provided with a plurality of vibrators generally indicated by arrows 33. The construction of the vibrators is more particularly described in relation to figure 9.

With respect to figure 6 of the drawings the downward force applied to the tamping head 6 can be intensified by the arrangement illustrated. Intensifier piston 30 which drives the tamping head 6 downwards is supported with respect to the frame and makes contact with the tamping head via shaft 34. Pressurised oil reservoirs 35 are communicable with 8 260 28 2 the chamber 36 of piston 11 via conduits 37. A larger double acting air cylinder 38 is mounted in alignment with piston 30 and a shaft 38A from piston 39 of the cylinder 38 extends into and is arranged to be extensible into a passage 40. When air pressure is applied to the top of the piston 39 shaft 38A advances into passage 40 closing off the low pressure oil supply and intensifying the pressure in chamber 38.

Cylinders 11 are used to raise the tamping head 6 and to apply downward force and intensifying cylinder 30 boosts downward pressure. On the upward stroke of the tamping head 6 pressure is released from intensifying cylinder 30.

Figures 7 and 8 illustrate further possible arrangements for driving the tamping head 6 and mould table 7.

The tamping head 6 is provided with guides 10, side cylinders 11, and a intensifying cylinder 30. The cylinder 30 is connected to a reservoir 42 via a control valve 43. A motor and pump 44 supply the reservoir 42 with pressurised oil and an air valve 45 admits low pressure air behind piston 46 of reservoir 42 to intensify pressure. Pump 44 can also pressurise the cylinder 30 via line 47 and non return valve 48 bypass switch 49 allows high pressure oil to bypass reservoir 42.

A very similar system can be used to intensify pressure supplied to cylinders 13 for raising table 7 in the arrangement illustrated by figure 8. The circuit comprises valve 43, reservoir 42 pump 44, bypass switch and a non-return valve 48. The circuit can be run under normal pressure or intensified pressure as described in relation to figure 7.

With respect to figure 9 of the drawings the impact vibrators 33 of figures 5 and 5a are shown in more detail. A cylinder 50 ho' 9 260 282 generally indicated by arrow 51 and a bottom section 52 of each vibrator is connected to the cylinder 50 by assembly bolts 53of which only one is illustrated. The bottom section 52 houses a members 54, 55, 56. Air is fed above and below the valve members via inlets 57A. Member 54 is cup-shaped and has a central aperture 58, member 55 comprises a ring 59 and a hollow stem 60 and valve member 55A. Air supplied below the assembly 51 causing turbulence and subsequent reciprocation and the vibrators which as previously described are positioned adjacent the mould table. An outlet is provided at 57B. Impact vibrators of this construction are generally known, but have not previously been used in this application.

It is important that products formed by the apparatus of the present invention are of consistent depth.

The depth of each block can be varied by factors such as density and quantity of the mix received form the hopper, the amount and timing of vibration and the tamping of the material within the mould. The present invention uses conditional inputs to control a looping function to alter standard "pre-vibration" timing control. Pre-vibration is the vibration applied to the mould table as a mix is received by a mould below the drawer. The operational sequences of the present apparatus can be adjusted to achieve consistent product depth. Figure 10 of the drawings shows a sensor 61, which checks on the depth of products from the moulds. If the sensor 61 detects that the product is undersized or oversized this information is fed to a sequence controller 62 to alter the looping function of its program up and down adjusting a pre-vibration timer 63. 26028 Aspects of the present invention have been described by way of example only and it will be appreciated that modifications and additions thereto may be made without departing form the scope thereof as defined in the appended claims. 11

Claims (13)

1. WHAT WE CLAIM IS: Apparatus for manufacture of moulded products comprising a frame, a tamping head supported by the frame, a mould table beneath the tamping head said mould table being adapted to receive and support a product mould, means for reciprocating the tamping head towards the mould table, and means for raising the mould table comprising a pair of hydraulic cylinders, a reservoir of pressurised fluid communicable with the hydraulic cylinders and a control valve positioned between the reservoir and the hydraulic cylinders said control valve having a piston therein which controls the supply of fluid to the hydraulic cylinders to extend same, and then by further movement intensifies the pressure within each cylinder to lock the mould table in a moulding position and isolates the respective cylinders from the reservoir.
2. Apparatus as claimed in claim 1 wherein the control value comprises a cylinder body having a piston chamber with an outlet chamber separate outlets to the hydraulic cylinders from said outlet chamber, a piston within said piston chamber said piston having a first piston shaft which extends from the piston in one direction and a second piston shaft which extends into the outlet chamber in the opposite direction, the piston being capable of advancing and retracting within the piston chamber, and said outlet chamber and the second piston shaft having complimentary first and second sections, said second sections being of reduced cross-sectional area, the outlets from the outlet chamber being communicable with respective hydraulic cylinders, the arrangement being such that with the control valve in an open position pressurised liquid can pass intellectual property office! of n.z. - 3 APR 1998 RECEIVED 12 INTELLECTUAL PROPERTY OFFICE OF NZ - 3 APR 1998 RECEIVED freely into the hydraulic cylinders and on further advancement 61 Iflti (Jliiuii the- second piston forces a residual amount of fluid from said first and second outlet chambers to said hydraulic cylinders further increasing pressure in each of the cylinders.
3. 3. Apparatus as claimed in claim 2 wherein the first and second outlet chambers are of equal volume.
4. 4. Apparatus as claimed in claim 2 or claim 3 including sealing means between the inner walls of the first and second sections of the outlet chamber and the first section of the piston and the second section respectively of the piston.
5. 5. Apparatus as claimed in any one of claims 1 to 4, including means for advancing the piston within the control valve by an allowable increment once the mould table is extended into its raised position.
6. 6. Apparatus as claimed in any one of claims 1 to 5 including vibration means for vibrating the mould table comprising a plurality of selectively positioned impact vibrators each having impact shafts arranged to repetitively impact on the mould table at high speed to vibrate same.
7. 7. Apparatus in claim 6 wherein the mould table is supported independently of the frame and the vibrators impact directly on the table surface.
8. 8. Apparatus substantially as herein described with reference to the accompanying drawings.
9. 9. Apparatus substantially as herein described operated in accordance with the sequences described in relation to Figure 8. 13
10. 10. Apparatus for the manufacture of moulded products as claimed in any one of claims 1 to 9 further including, vibration means for vibrating the mould table comprising a plurality of selectively positioned impact vibrators each having impact shafts arranged to repetitively impact on the mould table at high speed to vibrate same.
11. 11. Apparatus as claimed in claim 10 wherein the mould table is supported indirectly from the frame and the vibrators impact directly on the table surface.
12. 12. Apparatus as claimed in claim 11 wherein the mould table is supported by a pair of hydraulic cylinders.
13. 13. Apparatus for the manufacture of moulded products as claimed in any one of claims 1 to 12 comprising a frame which includes means for measuring the depth of moulded product, sequence control means for controlling pre-vibration (as defined herein), and adjusting the timing of pre-vibration prior to tamping of product within the moulds. MARSDEN MACHINERY LIMITED by it's Attorneys INTELLECTUAL PROPfflTY OFFICE OF N2. - 3 APR 1998 RECEIVED JAMES A WELLS 14