BACKGROUND OF T INVENTION The manner of producing concrete blocks has changed dramatically over the recent years. Now, this industry has venture into mass production of concrete blocks by using rapidly operating machines. These types of machines can produce multiple blocks of concrete at any given time. Further to this, the block produced using the said machines were incorporated with tongue and grooves. The tongue and grooves were provided on the top surface and on all four- side surfaces of each concrete block. The inner side of a mould into which concrete is poured in, created the tongue and grooves on all four-side surfaces and a compacting plate which is lowered onto the mould to compress the concrete created the tongue on the top surface of the concrete block. To provide grooves on the lower surface of the concrete blocks at was necessary to provide multiple core bars, which are retractable from the mould at a sufficient speed to allow the newly moulded concrete block to be stripped from the mould and lowered by a pallet onto a conveyor for transportation and thereafter stored. The speed of retracting the core bars from the mould has to be synchronized with the concrete block-forming machine. If this is not done, the when the completed concrete block is stripped onto a pallet, the concrete block will be destroyed by the core bars, which are still positioned in the mould. Tbis can also cause the entire machine to stop operating, as the force applied thereto by the machine onto the core bars would have bent the core bars. This will further damage the coie bars assembly, as the bent core bars cannot be retracted from the mouid. One attempt was made to synchronize the speed of the core bars and the concrete forming machine. This was done by connecting a plurality of core bars onto a single, heavy-duty hydraulic ram, which was configured to retract the said core bars from the mould. However, such core bars putters have proved to be a problem as it was heavy, bulky and caused serious space problem. Further to this, this type of core bars putters are custom made items and are not readily adapted to be used with other concrete block-forming machine. Other than that these type of core bars putters are subject to guidance problem in respect to the elongated core bars and are also subject to vibration problems in respect to the intense vibration

of the block-forming machine during the moulding process. But the main disadvantage of this type of core bars putter was that the use of a single hydraulically operated raao resulted in a relatively slow acting core putter assembly, which interferes with the normal production of the concrete blocks.

To overcome the above-mentioned problem, Vatterott (US 4, 427, 355) introduced some improvements in the configuration of the core puller assembly. Generally, what Vatterott had done was he replaced the heavy and bulky hydraulically moved ram into a bank of interconnected core puller assemblies, each capable of moving independently of the other core puller assembly. Each of the said core putter assembly comprises of a cylinder, and a piston slideably positioned within the cylinder and having. a rear-wardly extending connecting rod.

Each of the core putter assembly further includes a core bar deposed in sidc-by-side relation below the cylinder and connected to the piston connecting rod for movement with said connecting rod. Each cylinder carries a front and rear guide unit to receive the core bar in sliding elation to guide the core puller bars into the mould assembly. Further to this, Vatterott has also introduced a cylinder using pneumatic air supply to operate, which includes a surge tank and a control system for controlling the supply of pressurized air to the cylinders In other words, Vatterott has introduced a tight-weighted core puller assembly, which includes muttiple core bars (two core bars for each concrete block), in which each core puller assembly is connected to the pneumatic air supply unit separately or independent of the parallel core puller assembly. This way, Vatterott was able to solve the synchronize problem as the core putter assembly is now much lighter and the core bars could be retracted quickly at a higher speed by pneumatic means.

However, the present inventor has notice some disadvantages in the core puller assembly as described by VatterotL The first disadvantage is that even though the core puller assembly of Vatterott successfully solved the timing and synchronize problem between the concrete block forming machine and the core puller assembly, it has created another problem within the core putter assembly itself Each cylinder of the Vatermtt's core puller assembly is connected to the pneumatic air supply unit In other words, each of the cylinders is moveable independent of the other. Because of this, it become important to ensure that all the cylinders are moved into the mould and retracted thereafter at the same time. Each cylinder must be synchmnized with one another when the core puller assembly is in operation. However, this has shown to be difficult to achieve, as each of the eytinders ate not connected to a single or universal connecting means or moving means to extend the core bars into the mould and

thereafter retracting the same. No technical provision was provided to overcome this problem at that time.

Another disadvantage was rotating to the piston held in each of the cylinders of Vatcrron core putter assembly. The configuration of the said piston and the cylinder was designed to move the piston from one terminal end of the cylinder to the other terminal end of the cylinder. As the piston slideably moves in the cylinder at a high speed and approaches one of the terminal end portions of the cylinder, the trapped between the piston and the terminal end portion of the cylinder is quickly disposed. The trapped air is disposed through space between the external circumferential surface of the piston and the internal circumferential surface of the cylinder. This results in the piston to hit hard on the teminal end portion of the cylinder as there is no air available to create an'air cushion'surrounding to absorb the impact of the fast moving piston. This would furthcr lead in damaging both the cylinder and the piston after sometime and may involve additional cost to repair the damage parts. This disadvantage could interrupt the normal operation of the block-forming machine. This could further result in the manufacturer unable to achieve its production targets in time and involve in high maintenance and repairs cost. Another disadvantage of this core putter assembly is that there are too many moving parts, which are exposed to wear and tear problems. Further to this all the said moving parts need to be maintained at all time other wise it may cause major bleak down in the brick-forming machine. Yet another disadvantage observed by the present inventor is that the core assembly as described by Vatterrot is not a universal core assembly, i. e, one type of core assembly is- designed and configure to be used in conjunction with a block-forming machine to manufacture one type of concrete btoek. tf another type of concrete block is to be manufacture, then the entire configuration and design of the core puller assembly have to be changed too. The process of changing a new core puller assembly to suit a different type of-concrete block involves reeonfiguratmg the entire block-forming machine and the core putler assembly, inctuding all the sensors and electronically triggered components, realignment of the entire machine, redoing the setup procedure to control the amount of concrete to be poured in and the pneumatic pressure required to move the core bars and etc. Another disadvantage of the Vatterrot core pull assembly is that, each of the core puller assembly is connected to the surge tank via a plurality of independent connecting hose. The lengffi of each connecting hose for each core putter assembly differs from the parallel core puller assembly. The disadvantage is observed to occur when the core puller assembly with the shortest connecting hose in length extends and retracts the core bars faster than the core puller assembly with a longer connecting hose. The result is that when one cycle of operation to produce a plurality of concrete blocks completes, the

percentage of obtaining a defected concrete blocks is high. This further leads to wastage of raw materials and time. This is not acceptable as the raw material used thereto and time is a big factor in this industry.

Therefore, it's an objective of the present invention to overcome the above mentioned disadvantages by providing an improved version of the core puller assembly, which ensures that the normal operation of the block-forming machine is never interrupted by the core putter assembly. Yet another objective of the present invention is to ensure that the piston in the cylinder in provided with provision to allow the trapped and compressed air to bleed gradually and thereafter allowing the effect of air cushion in the cylinder. Another objective of the present invention is to reduce the number of moving parts by providing interconnected means. In other words, all independently moving parts are connected to one main moving means in which when the main moving means is activated, it will further initiate movement to the interconnected moving parts therein. Yet another objective of the present invention is to introduce a universal core putter assembly, which does not require major changes to the entire machine when different type of concrete block is to be manufacture by using the same core puller assembly- SUMMARY OF THE IN 'FNTI_9N A core puller assembly used in conjunction with a concrete block-farming machine comprising of a plurality of independent core puller units securely mounted onto a support member and wherein each of the core puller units includes a cylinder having a front end and a rear end, a piston mounted in the cylinder for slidingly moving along the longitudinal length of the cylinder, a core bar connected to a piston rod on each of the piston and a drive unit means.

The core puller assembly according to the present invention includes improvements comprising of one core puller unit mounted in a housing chamber and wherein the core puller unit further comprising of a plurality of identical cylinders having a front end and a rear end and wherein each of the cylinders are mounted spaced apart from each other and side by side. The improvement further includes a piston head mounted in each of the said cylinders to-slidingly moveable along the longitudinal length of the cylinders, an elongated piston rod secured to the piston and extending outwardly from one of the ends of the cylinders. The terminal end portions of each of the outwardly extending piston rods are removably mounted to a slideable ptate. The core putter unit is further connected to the drive unit means via a plurality of connecting hoses.

20The improvement according to the present invention further comprises of at least two spaeed-apart air inlets points provided on the external circumferential surface of each of the cylinders. The internal terminal end seclions of each of the cylinders are provided with two spaced apart plug means to receive the when in operation. Each of the spaced apart plug means arc provided with a hole respectivety to ailow tspped air to escape thereto.

The piston head (44) in each of the cylinders are provided with a plurality ohio'rings along the circumferential surface of the said piston head (44and wherein when the piston heads (44) arc slideably moved along the longitudinal length of the cylinders the trapped air therein is gradually exhausted either through any one of the holes at any one time. The slidebale plate according to the present invention is provided with a plurality of spaced apart apertures to receive the core hc slideabie plate is held in its positioned by the plurality of spaced apart piston rods of each cylinder. Each air inlet points on each cylinder are independently connected to their respective openings. The length of each connecting hoses for each cylinder are identical to one another.

The drive unit according to the present invention is a pneumatic surge tank. The operation of the core putter assembly is synchronizabte to the operation of the concrete block-forming machine via a plurality of sensor means and a plurality of electronic devices and wherein all the above are controlled by a main central processing computer. The core bars of the present invention is selected from any type of geometrical shape to create a desired groove on a concrete block A method of opening a core puller assembly according to the present invention comprises the steps of :- (a) in a first position having the piston rods retracted in the cylinders and correspondingly having the slideable plate retracted in the same direction and thereafter resulting the cote bars to be positioned space apart from a concrete block mould assembly, (b) activating a drive unit to slideably move the piston from the first retracted position to a second extended position and thereafter resulting the slideable plate to move in similar direction.

(c) in the second position having a plurality of spaced apart core bars pre mounted onto the slideable plate to enter into the lower portion of the mould assembly,

(d) having a premix setting materials to be poured, into the mould assembly and thereafter vibrating the said material (e) in a third position, having the piston slidebaly move into its first position as in (a) by activating the drive unit and thereafter resulting the core bars to be positioned away from the mould assembly, (f) stripping the completed concrete blocks from the mould assembly onto a pallet and thereafter transported for storing, and (g) repeating steps (a) to (f) for each cycle of operation in producing the concrete blocks (t4).

BRIEF DESCRIPTION OF THE DRAWINGS Figure I is a perspective view of. the present invention used in conjunction with a mould assembly of a concrete block-forming machine- Figures 2A-2G are perspective view of examples of concrete blocks manufactured by using the present invention.

Figure 3 is another perspective view of the present invention as shown in Figure 1.

Figure 4A is a cross sectional view of a cylinder of the as shown in Figure I in a retracted position.

Figure 4B is a cross sectional view of a cylinder as shown in Figure 4A in an extended position.

Figure 5 is a plan view of the present invention.

DETAILED DESCRIPTION OF PRESENT INVENTION Referring now by reference numerical to the accompanied drawings and first to Figure t, it would be understood that the core puller assembly (10) of the present invention is used in conjunction with a mould assembly (12), which forms part of a concrete block machine (14) (not illustrated) tor producing tongue and grooved concrete blocks (16) of the type which is

shown in Figure 2. Other examples of concrete blocks, which can be also manufactured by the present invention is also shown in Figures 2A to 2G.

The core puller assembly (10) of the present invention includes of a plurality of spaced apart cylinders (18), which are identical to each other. In the present, at least six cylinders am provided therein. The core puller assembly (10) further includes a support member (20), constituting as a support means to securely hold and support the said cylinders (18) in their respective position. The said support member (20) is a rectangular shaped rigid structure preferably made of aluminum because of its properties such as aluminum is a lightweight material as easy to obtain. Other type of rigid materials such as metal and steel can also be utilized. The said support member is a"U"shaped structure in cross section, Figures 3 and 5.

One of the terminal ends of the said support member (20) is provided with an integrally connected metal plate (22). The other opposite end (24) is a free end. The top surface of the support member (20) is provided with at least two openings (26,28). Said openings (26, 28) are positioned spaced apart from each other. The function of the said openings (26,28) will be described later in the descriptions.

The above-mentioned described configuration of the support member (20). creates a chamber like section into which the cylinders (18) are housed therein. For ease of describing. only one of the cylinders (18) will be described in detail, as the other cylinders (18) are identical to each other in design, configuration and function. The cytinder (t8) consists of a cylindrical tube (30) having a front end (32) and a rear end (34). The front end (32) is referred as the side of the cylinder (18) adjacent to the mould (12) provided in the concrete-forming machine. The internal area of the front end (32) and the rear end (34) of the cylindrical tube (30) are provided with a front plug means (36) and a rear plug means (38) respectively : Both the said front and rear plug. means (36,38) are cylindrical shaped members, Figures 4A and 4B. The rear plug means (38) comprises of a one part smaller external dimensioned portion and the other part a largcr external dimensioned portion. A continuous flange (40) is provided at the border of the said smaller and larger dimensioned portions. The area after the flange (40) extending into the larger dimensioned portion is tapered up to a predetermined distance from the flange (40) and thereafter a bore is provided extending from the end of the tapered portion to the terminal end or the rear plug means (38) with-constant internal diameter. The said rear plug means (38) is marginally smaller than the cylindrical tube (30) and therefore can be introduced into the rear end (34) of the cylindrical tube (30). The rear plug means (36) is held in place in the cylindrical tube (30) by providing a pin (42). The pin (42) is introducible into openings, which are provided

on the cylindrical'tube (30) and on the rear plug means (36). When the rear plug means (36) is placed in its position, the smaller external dimensioned portion is suspended in the cylindrical tube (30), Figures 4A and 4B.

Thé front plug means (36) generally have the same configuration as the rear plug means (38). The only difference between both the said plugs is that the front plug means (36) is not provided with a tapered portion. A bore with constant diameter is provided from one end of the Front plug means (36) extending to the other end of the said front plug means (36). The front plug means (36) is placed in position in the cylindrical tube (30) by another pin (43). Both the said plugs (36, 38) arc provided with a plurality ofO"rings to allow easy introduction into the cylindrical tube (30).

The cylinder (18) is further provided with a piston head (44) and its corresponding piston rod (46), Figures 4A and 4B. The piston head (44) is a cylindrical shape member, which can be divided into three parts, in which the middle part of the piston head (44) has a greater diametrical dimension than the other two parts. The smaller dimensioned part of the piston head (44) head (44) has a smaller diametrical dimension than the smaller diametrical dimensions of the front and fear end plugs (36,38). The external surface of the piston head (44) is provided with a plurality of'0'rings to allow the piston head (44) to move smoothly along the longitudinal length of the cylindrical tube (30). A bore is provided extending through the entire longitudinal length of the piston head (44). One end of the piston rod (46) is matingly secured in the bore of the piston head (44). The other terminal end of the piston rod (46) is extended to the front end (32) of the cylindrical tube (30) through the front plug means (36) and projecting outwardly away from the front end (32). The cylinder (18) is further provided with a first air inlet point (48) and a second air inlet point (50), Figure 4. The first air inlet point (48) is positioned at the terminal end portion on the front end (32) of the cylinder (18) and approximate to the pin (44). The second air inlet point (SO) is positioned at the terminal end portion on the rear end (34) of the cylinder (18) and approximate to the pin (42). The purpose of these air inlet points (48, 50) will be described later in the description.

The above has described in detail regarding one of the cylinder (18) of the present invention. The above description also applies to the other cylinders (18) as each is identical to the other. All the said cylinders (18) are positioned in the mid section of the chamber like member on the support member (20) by a plurality of brackets and screw means. Other types of securing means to securely place the cylinders (IS) in position can also be adapted.

The manner each of the cylinders (l8) is secured on the support member (20) and the working mechanism of the core puller assembly (10) will now be described in detail. Each of the cylinders (IX) as described above is securely positioned in their predetermined position, spaced apart and parallel to each other. All the projecting ends of each of the piston rod (46) on each cylinder (18) are removeably mounted to a moveable plate (52), Figure 5. The said movable plate (52) is shaped in cross section : The said moveable plate (52) is design and configured to work co-operatively with the supporting member (20) when the core puller assembly (10) is in use. The first and second air inlet points (48, 50) on each of the cylinder (18) are inierconnected to each other respectively via a plurality of connecting hose. A drive unit (54) constituting a controlled air supply, which receives air from a compressor is connected via a connecting hose to one of the cylinders (-IS) through the openings (26, 28).

The other end of the moveable plate (52) is provided with a plurality of apertures, which are positioned at their predetermined positions along the longitudinal length of the said mounting plate (52). The apertures are more particularly positioned in a seL Each set consists of two parallel apertures and the distance between the said parallel apertures should correspond to the width of a concrete block, which is to be manufacture. Figures 2A to 2G. For example, in the present invention, the moveable plate (52) is provided with three sets of apertures for manufacturing three identical concrete blocks at the same time. Lets refer this as the first group of apertures for Block A. The same moveable plate (52) can further be provided with another group of apertures to manufacture Block B, which maybe smaller or larger than Block A. The number of sets of apertures in group B need not be the same as in Group A. This can further go on to Groups C, D and etc. This is in accordance with the objective of the present invention to have a universal core puller assembly. Each of the said apertures is design to removeably receive an elongated core bar (56). Each set of apertures will have two a core bars (56) introducible therein two create two identical grooves on the lower surface of a concrete block (t6). The core bars (56) of the present invention can be selected from various geometrical shapes in order to create a desired groove on the concrete block (16).

The working mechanism of the present invention will be described in detail now. As mentioned earlier in the description, the present invention is used in conjunction with an existing concrete block-forming machine The sequence of operation begins with the core bars (56) fully extended into the mould (12) of the concrete block-forming machine (14). When the core bars (56) are in place in the mould. a pallet member is moved into position below the said bars (56). Following this, the mould (12) is filled with concrete and vibration of the machine (14) is commenced. After a predetermined period of time the vibration is terminated. Prior to the termination of the vibration of the mould, the machine sends a signal to the drive unit (52 which actuates the each piston head 44) in cach cylinder (IS) by supplying air through the first air inlet points (48) on the cylinders (18), The piston heads (44) with the piston rods (46) held therein will slidebaly move from the front ends (32) of the cylinders (18) towards the rear ends (34) of the cylinders (18). This will further result in the moveable plate (54) to move in the same direction and thereafter resulting in the core bars (56) to be retracted from the mould (12), Figure 4A. Further movements of the piston heads (44) in each cylinder (18) arc restricted by the rear plug means38). As the piston heads (44) moves towards the rear ends (34) in each of the cylindres (18), the trapped air is compressed quickly. This trapped and compressed air is gradually exhausted via a hate (58) provided on the circumferential of the rear plug means (38).

This will result in creating an air cushion effect at the rear plug means (38) portion to absorb the impact from the fast approaching piston head (44). The trapped air in unable to blced through the space between the external circumferential surface of the piston head (44) and the internal circumferential surface of the cylinder (18) because the said air cannot bleed trough the 'O' rings provided on the piston head (44). The core bars (56) are retracted at a high speed as the time different when the vibration is complete and the stripping actions begins, is about one fourth of a tenth (4/10) of a second. The completed blocks are lowered onto the pallet and are transported by a conveyor to the storage area. After a predetermined period of time, the machine (14) sends another signal to the drive unit (52), which actuates each of the piston heads (44) in each cylinder (18) by supplying air via the second air inlet point (50) on the cylinder (IS). The piston heads (44) with the piston rods (46) held tE will slidebaly move m the rear ends (34) of each of the cylinder towards the front ends (32) of. the said cylinders (18). This will result in the moveable plate (54) to move in the same direction and thereafter resulting in the core bars (56) to le enter the mould Figure 4B. This is done before another pallet is returned into its position for the next cycle. As the piston heads (44) moves towards the front ends (32) in each of the cylinders (18), the trapped air is compressed quickly. This trapped and compressed air is exhausted via another hole (60) provided on the circumferential of the front plug means (36) as described earlier. Further movement of each of the piston heads (44) in the cylinder (18) is restricted by the front plug means (36). This is a continuous cycle.

In the present invention, three concrete blocks with tongue and grooves on its sides are produced in each cycle. This can be increase by changing die number of moulds and the number ofeote bars (56). When a different size. of concrete block is to be manufacture, a user only need

to reposition the core bars (56) in the apertures on the moveable plate (54) according to the size of the mould. Therefore, the realignment of the core pullcr assembly with the concocte block- forming machine is no longer essential. Since the moveable plate (54) is not permanently secured to the piston rods (46), therefore the entire moveable plate (54) can be replaced with another moveable plate, which includes a new sets/group of apertures. The entire working system of the present invention and the concrete block-fonning machine (14) is conlrouable by a plurality of sensor means and devices, which are connected to a computer meons.

Further to this, the length of each of the connecting hose, connecting the openings (26, 28) on the support member (20) to the first and second air inlet points (48, 50) on each cylinder are identical to on another-The connecting hose connecting the cytinder. (I8) nearest to the openings (26, 28) is preferably bent. The connecting hose connecting other cylinders (18) are gradually stretched into its full length. By doing so, none of the piston will slidebaly move Casecr than the other piston heads (44) as the movements of the piston heads (44) is synchronized with each other. This ensures that, the concrete block produced at each cycle of operation is always in a perfect condition as required by the manufacturer.

In the present invention, the drive unit is a pneumatic surge tank. However other type of drive unit such as hydraulic means can also be utilized as Iona as this type of drive unit is capable of extending and retracting the core bars (16) within the required time.