NZ213947A - Ready mixed concrete delivery truck;auxiliary mixer for batch modification - Google Patents

Description

2 13 9 4 7 Priority Date(s): TT7 Complete Specification Filed: Cass: OCTM986* ■ Publication Date: P.O. Journal, No: N.Z. PATEh'T 0! - -- F 2 3 OCT 1985 Received N.Z.No.

NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION " READY MIXED CONCRETE DELIVERY TRUCK " We, ROADSTONE DUBLIN LIMITED an Irish Company of Fortunestown, Tallaght, Dublin 24, Republic of Ireland do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : - 2 V 39 This invention relates to ready mixed concrete delivery trucks for the supply of building mortars and concrete, hereinafter referred to collectively as "mortar", in batch loads to building sites.

Traditionally, building mortars have been mixed on site from the basic ingredients, aggregate, cement, hydrated lime or chemical plasticiser, plus pigments where a specific colour is required. The aggregate, lime (and colouring pigments) may be premixed by specialist mortar suppliers, 10 with cement being mixed in on site before usage. The foregoing mortars have a relatively short "pot" life and several small lots must therefore be mixed each day.

Mortars of this type can also be produced off site in a conventional ready mixed concrete plant and then delivered 15 by truck to to the building site. However, as the short "pot" life requires several small lot deliveries each day the costs associated with this would make such a practice prohibitively expensive. Solutions to these problems include the use of 1) Truck mounted batcher mixers, whereby all the necessary ingredients are carried on board to be proportioned and mixed on site; and 2) Truck mounted mixers which are charged 25 with materials before dispatch.

An operational analysis of both suggested solutions shows that both solutions suffer from the common drawbacks of high operating costs and lack of versatility.

A successful solution to the basic problem has been found by using retarded set mortars. This successful solution is achieved by the addition of chemical retarders to factory mixed mortars thereby significantly increasing its "pot" life, which may be upwards of one day depending on the amount of added retarder. This development has removed many of the obstacles previously associated with factory mixer mortar, and has led to the situation where ready to use factory mixed mortar is delivered daily to sites usually on the same lines as a milk round, where the delivery truck calls at approximately the same time each day and delivers sufficient mortar to last until the next call on the following day. Delivery is usually by conventional ready mixed concrete delivery trucks, but may also be by the mobile batcher or mixer trucks referred to earlier. This obviates the need for a builder to have site mixing facilities with resulting cost savings. Also, as mortar is always available on site there is no lost start up time on the site or left over unusable mortar each day and this offers significant economical advantages.

The market has recently developed for retarded set mortar to be supplied ready coloured. However, supplying ready coloured mortar in batch loads to a building site is not practical as coloured mortar is usually only required in small lots, typically in amounts not exceeding 1 cubic metre, whereas each delivery truck has a capacity of several times that amount, and it is highly unlikely that full loads of one particular colour would be required during one delivery round. Also, many building sites may require simultaneous delivery of both coloured and uncoloured mortar and clearly this would not be possible using only one conventional delivery truck for a delivery run. To use two such conventional delivery trucks for one composite mortar delivery to a building site would be uneconomical.

Further it has also become apparent that the market now demands relatively small batch loads of building mortar 213947 having different characteristics - such as a different consistency, a different setting time or a different strength. The same problem as described above in relation to the mortar appearance or colour, also arises in relation 5 to the other mortar characteristics since the demand for the same mortar cannot be expected from one site to another.

Therefore, in order to permit the economical delivery of factory mixed mortar of differing characteristics to one or more sites, it is an object of the invention to provide a 10 delivery truck with means for further processing a portion or portions of a single truck load of factory mixed mortar, on one or more delivery sites, by blending with such portion or portions an additional material, such as a colouring pigment, without affecting the remainer of the truck load of 15 mortar.

Accordingly, the present invention provides a ready mixed concrete delivery truck comprising a main mixer mounted on the truck chassis and an auxiliary mixer also mounted on the truck chassis adjacent to the main mixer, the 20 main mixer being arranged to supply mortar to the auxiliary mixer to permit blending therein with an additional material without affecting the characteristics of the mortar remaining in the main mixer, the auxiliary mixer having at least one discharge means for delivery of the blended mortar 25 to a site location.

The invention will be understood from the following embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which Fig 1 is a side view of a ready mixed 30 concrete delivery truck according to the present invention; Fig 2 is an end view of the truck of Fig 1; and Fig 3 is a plan view of the truck of Fig 1. 35 Referring to the accompanying drawings the ready mixed concrete delivery truck of the present embodiment comprises 2 I 394 7 a conventional wheeled truck chassis 1 having a cab 2, a fuel tank 3 and conventional truck operational components (not specifically shown), a rotatably mounted main mixer 4 provided with conventional drive means operatively associated with the truck engine, and a discharge chute 4a^ Mounted on a bracket member 6 rearward of the main mixer 4 is an auxiliary mixer 5 of the horizontal shaft ribbon type. A driven shaft 7 carries a drive gear 8 and the mixer ribbon blades and may also be fitted with additional angled paddle blades. The motive power operatively associated with the drive gear 8 is the truck engine. The auxiliary mixer 5 is provided with two discharge doors 9 and two associated delivery chutes 10. The delivery chutes 10 are shown in the drawings delivering mortar to bins 11.

In use, the main mixer 4 is filled to capacity with factory mixed mortar and the truck 1 proceeds on its delivery run - the milk round - from one building site to the next delivering a portion of its load to each site as required. If the customer simply orders standard "ready to use" mortar the required amount is simply discharged via the chute 4a direct from the main mixer 4 or alternatively from the main mixer 4 through the auxiliary mixer 5. On the other hand if the customer requires a coloured mortar then the required amount of mortar is discharged from the main mixer 4 into the auxiliary mixer 5 and the appropriate amount of a colouring pigment added to the mortar in the auxiliary mixer 5. The auxiliary mixer 5 is then actuated through the drive 7 and 8 and the mortar in this manner suitably coloured. The relevant consignment of mortar is thus coloured at the point of sale, without any interference with the characteristics of the balance of the mortar in the main mixer 4. The truck operator may conveniently be supplied with packaged measured quantites of different colouring pigments so that the addition of the relevant colouring pigment is quite easy. 213947 It is envisaged that the auxiliary mixer may be mounted upon a load measuring device operatively connected to a visual readout, so that the amount of a mortar load delivered by the main mixer to the auxiliary mixer may be 5 accurately measured on each occasion and cumulatively measured for the complete delivery run.

It will be readily appreciated that the described procedure for colouring of a mortar load in the auxiliary mixer is the same procedure which is to be followed for the 10 variation of any of the other characteristics of the mortar, the additional material required for the appropriate variation of the particular characteristic of the mortar being added in the correct amount relative to the mortar load in the auxiliary mixer and the mixture being further 15 mixed for on the spot delivery to the customer.

The capacity of the auxiliary mixer may preferably be ^ cubic metre. Further, the motive power to the auxiliary mixer may be an engine separate from the truck engine or it may be an electric motor which may be powered by an on site \ electrical supply.

It will be understood that a conventional main mixer does not have means associated with it to allow the main mixer to discharge a measured quantity of mortar. The provision of the adjacent auxiliary mixer which has a 25 fixed capacity, and which may also be provided with an associated load measuring device, provides the main mixer with a readily available measure to allow the discharge of mortar from the main mixer to be easily quantified. 2 13947 7 20 # CLAIMGi—

Claims (6)

WHAT WE CLAIM IS:-

1. A ready mixed concrete delivery truck comprising a main mixer mounted on the truck chassis and an auxiliary mixer also mounted on the truck chassis adjacent to the main mixer, the main mixer being arranged to supply mortar to the auxiliary mixer to permit blending therein with an additional material without affecting the characteristics of the mortar remaining in the main mixer, the auxiliary mixer having at least one discharge means for delivery of the blended mortar to a site location. •

2. A concrete delivery truck as claimed in Claim 1, wherein the auxiliary mixer is mounted on the truck chassis rearwardly of the main mixer.

3. A concrete delivery truck as claimed in Claim 1 or 2, wherein the auxiliary mixer is of the horizontal shaft type.

4. A concrete delivery truck as claimed in Claim 1, 2 or 3, wherein the main and auxiliary mixers are both driven by the engine of the truck.

5. A concrete delivery truck as claimed in any preceding Claim, wherein the auxiliary mixer is mounted on a load measuring device.

6. A concrete delivery truck substantially as described herein with reference to the accompanying drawings. ROADSTONE DUBLIN LIMITED Bv their Attorney Registered Patent Attorney