THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

INDEX

[001] TECHNICAL FIELD OF INVENTION

The present invention relates to a self regulating apparatus for pumping concrete and thick pasty mass. In particular, the present application relates to a concrete pump which uses a simple static hydraulics WITHOUT USING A CONVENTIONAL HYDRAULIC PUMP and using a mechanical drive so as to drastically bring down the capital and operation cost apart from simplifying the pumping operation.

[002 ] BACKGROUND OF THE INVENTION / PRIOR ARTS

[002.01] Many inventions have been well documented in the history of development of concrete pumps over the years. A concrete pump is an apparatus which is used to pump concrete over a distance which includes horizontal & vertical displacement of concrete.

[002.02] Today a variety of concrete pumps are available in the market, which include simple ball valve pumps for small aggregate size and advanced concrete pumps using electronic managing systems and heavy duty hydraulic systems having load sensing high precision hydraulic pumps. The concrete pumps are also available in various capacities, trolley mounted and truck-mounted versions.

[002.03] However, still there remains a big void in terms of capacity and cost effectiveness and ease of production for the pump manufacturer. The available concrete pumps are highly complex and thus cannot be easily manufactured by a small manufacturer having limited resources. There also exists a huge entry barrier for the end user in terms of very high initial capital cost irrespective of his job size. This patent application therefore discusses a novel concept which uses simple basic laws of static hydraulics in combination with a highly cost effective mechanical drive and mechanical reversal of pumping strokes which not only increases the mechanical efficiency but also is very easy to manufacture for manufacturer of any size. [002.04] There has been a particular segment of market, wherein the customers have limited volume concrete work and for whom a small machine is sufficient and big machines may not be required. Also the size of the work calls for more economical operation. This patent application enables to make concrete pumps in various capacities for pumping commonly used mix designs of ready-mix concrete, including very small equipment depending upon specific requirements.

[002.05] Therefore there has been a huge requirement of such a concrete pump which can be made even in smaller versions as well, has a very reasonable initial capital investment and a simple cost-effective operation. 3] TECHNICAL PROBLEM :

[003.01] Until the early 20th century, concrete was mixed on the job site and transported from the cement mixer to the formwork, either in wheelbarrows or in buckets lifted by cranes. This required a lot of time and labor. As per our knowledge, In 1927, the German engineers Max Giese and Fritz Hull came upon the idea of pumping concrete through pipes. They pumped concrete to a height of 38 meters (125 ft) and a distance of 120 meters (130 yd). Shortly after, a concrete pump was patented in Holland in 1932 by Kweimn Jacob Cornelius (Jacobus Cornelius Kooyman). This patent incorporated the developer's previous German patent.

[003.02] Before we get into the prior arts and their limitations, let us have a look on the basic requirements of a concrete pump.

The concrete pump has to be a positive displacement pump. Therefore its suction and delivery ports should be closed to each other to avoid loss of pressure and slurry. The earlier pumps used rotary valves, followed by simple ball valves, etc. The major issue with these valves was that they could not effectively seal the delivery side from the suction side because of the nature of the material under pumping and the size of the aggregates. Let us consider a single piston reciprocating pump.

[003.03] The basic requirements of a simple reciprocating type concrete pump are:

1. The basic requirement is that the piston should move forward and reverse, with sufficient force enough to displace & suck the column of concrete.

2. When the piston moves forward the suction port should be closed and the delivery port should be open.

3. When the reverse stroke starts, the delivery port should be closed and the suction port should be open.

4. With the delivery port closed, the reversing piston should create low pressure and should suck the concrete from the open suction port.

5. At the start of the forward stroke, the delivery port should be open and suction port should be completely closed and the pumping cylinder should be filled with concrete. . There has to be a mechanism to control, advance or retard the opening & closing of the delivery & suction ports so as to have optimum efficiency and optimum fill. . There has to be some mechanism to change the direction of movement of the piston, i.e., forward and reverse. . All the reciprocating pumps whether single cylinder or multi-cylinder need the above basic requirements fulfilled.

[003.04] Since the invention of the first concrete pump using a mechanically reciprocating piston, there has been various inventions, which have achieved the above requirements by various means. a. Initially, the reciprocating pistons were driven mechanically with a CAM type arrangement. However, the reciprocating force could not be multiplied or the working stroke could not be changed. In the same design, the delivery and suction ports were operated by mechanical tie rods which had severe limitations of dimensions and size and types of valves used and the valve opening & closing control options were limited. b. Over the years, heavy duty load sensing reversing hydraulic pumps came into picture which increased the working pressure and the hence the reciprocating force. However, the use of pump-hydraulics made the equipment very costly apart from highly complicated and difficult to make even for the manufacturers as it involved several machined parts made to very high precision. Today majority of the pumps are using hydraulic pumps to drive the concrete pumps. c. A majority of the currently available concrete pumps use hydraulic systems either separate or in-built for reversal of directions of the reciprocating pistons. d. A few inventions are discussed hereunder to understand the means used by various inventors to fulfill the above mentioned basic requirements of a reciprocating concrete pump.

[003.05] The Concrete Pump patented under the patent application no US2017975 A in the year 1935 by J.C.Kooyman is displayed as Prior Art No. 1. This particular invention used a mechanical drive to operate a reciprocating cylinder by means of a cam type arrangement similar to the Internal combustion engine. The concrete pump made by Mr. J.C. Kooyman was provided with mechanically actuated rotary valves which regulated the suction and delivery ports. The mechanical actuations achieved by using simple mechanical tie rods having mechanical length adjustments. Kindly refer to the said prior art No.1 reproduced here for reference. This invention has been a tremendous breakthrough in the history of concrete pumps, which was followed by a no. of inventions. As the construction industry grew, the limitations of the invention became clear which were mainly related to the mechanical actuators which operated rotary valves which limited the aggregate size & the leakages through the valves causing leakage of slurry & pressure and subsequent choking, mechanical cam actuators had vibrations and the mechanical linkage which directly pumped concrete was found inadequate in force as the pumping lengths both horizontal & vertical increased during the course of time.

[003.06] The said invention overcomes the following short-comings of the J.C.Kooyman Concrete pump : Multiplication of force & increase or decrease in the stroke length : Since the J.C.Kooyman Pump was driven mechanically where in the mechanical drive was directly given to the reciprocating piston, the reciprocating force was constant & could not be multiplied. However the present invention overcomes this short-coming. Operation of the gate valves at a variable distance from the prime mover without vibrations: The J.C.Kooyman Pump was provided with rotary gate valves which were mechanically operated by mechanical tie rods having adjustments, which had severe limitation in terms of smooth operation and distance & direction of opeartion of the gate valves from the prime mover. This invention overcomes this short-coming thereby allowing the gate valves to be placed any-where as they are operated through hydraulic hoses. Reversal of direction & stopping of the pumping action without using a clutch: This feature was not possible with the J.C.Kooyman pump unless the pump used a mechanical gearbox having a reverse gear & a mechanical clutch. The reversal of direction helps greatly in clearing the choking of the concrete pipeline which is a must feature of all the modern concrete pumps. This invention overcomes this short-coming as well by using a three position directional control valve.

[003.07] The J.C.Kooyman pump has been cited as the closest prior art because it provided a mechanical drive to the concrete pump. However all the presently available concrete pumps are driven by a conventional hydraulic pump.

[003.08] Concrete Pump by Charles F. Ball in 1935, under US patent no. US1991342 represents a twin cylinder reciprocating pump driven by a hydraulic pump and having hollow steel balls acting as valves for opening and closing of the delivery and suction ports. The design is reproduced herewith as PRIOR Art No. 2. The hydraulic pump here is driven by an Internal combustion engine.

[003.09] One of the major limitations of this design was the use of ball valves. Ball valves are used even today but have certain limitations especially related to the aggregate size. Today also there are mechanically driven pumps which use ball valves. These pumps are small and are highly sensitive to the aggregate size.

[003.10] Majority of the other patent applications and patents since 1935 till today including the most advanced technologies relate to reciprocating concrete pumps driven by a conventional hydraulic pump driven by a prime mover. Some of the modern patents and patent applications are discussed randomly hereunder for clarity of subject

[003.11] US patent no. 3682575 dated 08/08/72 is related to the arrangement of pumping cylinders and outlet shape & design of valve bodies and is not related to the drive system. Similarly the US patent no. 3877847 is also related to pumping cylinders & gate valve design. Another US patent no. 3647325 describes a concrete pump having an arrangement of a common hopper & pair of pumping cylinders irrespective of the source of fluid pressure. [003.12] US patent no. US 2549851 dated 24/6/1946 describes a concrete pump which uses a conventional oil hydraulic pump. US patent no. 3712762 dated 23/1/1973 describes a very different method of pumping. Similarly US patent 3663129 describes a method to provide constant flow of concrete & arrangement of valves mounted in the hopper & is not related to the drive system. Another US patent 8439657 dated 14/5/2013 describes a concrete pump provided with a system which enables complete removal of residual concrete from the pump & is not related to the basic drive system of the pump.

[003.13] The US patent no. 5344290A describes a concrete pump which again uses a conventional hydraulic pump for providing fluid pressure. Another European patent no. EP 1847710B1 dated 15/7/2009 describes "Improved open circuit oleodynamic system to actuate &control a hydraulic piston pump "which also use a conventional hydraulic pump. Another European patent No. EP 0167635B1 dated 27/09/1989 also describes " Hydraulic circuit for the control of reciprocating piston pump" which relates to various types of control hydraulic circuits, however all of them use a conventional hydraulic pump. Another European patent no. EP 1906012A1 describes a pumping apparatus which also uses a conventional hydraulic reversing pump.

[003.14] All the modern concrete pumps which are available today manufactured by various leading manufacturers like SCHWING / Putzmeister / Sany /Zoomlion/ Reed etc, use variable displacement advanced hydraulic pumps for operating the concrete pumps. Some manufacturers use a separate hydraulic circuit to operate the delivery and suction valves. Some manufacturers still use sensors and limit switches to change the forward & reverse directions of the pumping cylinders by using conventional reversing hydraulic pumps. Some manufacturers use servo- piston circuits to change the swash plate direction for reversal of direction. These high precision systems are also controlled by sophisticated computer software. However it all adds to the capita! cost and a complex manufacturing.

[003.15] Hence there has been a long felt need to have a very simple self regulating concrete pump wherein all the basic requirements of the concrete pump as listed above are fulfilled by simple laws of basic hydraulics, without using the conventional hydraulic pump, thereby making it a very simple low cost reliable equipment easy to manufacture, service and operate. OLUTION TO THE PROBLEM:

[004.01] An Important object of the present invention is to provide a uniquely designed self regulating self timed concrete pump which - a) works on simple basic fundamentals of hydraulics without using a costly conventional hydraulic pump which is widely used in currently available reciprocating concrete pumps as mentioned above. b) has its own in-built system to achieve the forward & reverse strokes without a separate hydraulic circuit. c) has its own in-built system to achieve controlled & adjustable operation of the delivery & suction ports. d) can increase or decrease the number of strokes simply by changing the rpm. e) has a very low initial cost when compared to the conventionally available concrete pumps having conventional hydraulic pumps. f) is easy to manufacture, service and operate. gj is aoie to nanaie tne normally usea reaay-mix concrete or siuage h) is mechanically driven but having a variable reciprocating force and variable stroke length depending upon the requirement. i) could be made in various capacities as per the requirements of the end user simply by using components which are available of the shelf. j) can be operated & maintained even by a lay man. k). is compact and can be made in stationary, trolley or trailer mounted or truck-mounted.

I) is mechanically driven but has all the advantages of a modern hydraulic pump driven concrete pump without the cost & manufacturing hassles.

[004.02] Another object of the present addition is to provide a user friendiy apparatus for placement of concrete which is highly cost effective both in terms of capital & operational cost.

[005.00] DISCLOSURE OF THE INVENTION :

In accordance with the present invention there is provided a "Hydraulicaliy operated but mechanicaiiy driven & mechanicaiiy reversed impie Concrete Pump ^" which typically consists off the following components: a. A prime mover which can be an electric motor or a diesel engine, coupled with a suitable capacity reduction gearbox. b. A heavy duty steel fabricated off-centre drive from the said reduction gearbox, converts the rotary movement into longitudinal to and fro movement of a high pressure heavy duty double acting hydraulic cylinder, hereinafter called the main cylinder, which is fixed at one end and reciprocates to and fro due to the mechanical linkage. c. A minimum one, separate high pressure hydraulic cylinder, hereinafter called the drive cylinder is operated by the oil displaced from the main cylinder. The difference in cross section areas of pistons between the main cylinder and the drive cylinder result in multiplication or division of the force and increase or reduction in stroke length of the drive cylinder. d. The drive cylinder in turn operates a minimum one concrete pumping cylinder having a rubber Piston moving inside. e. Set of slide gate valves operated by hydraulic cylinders on both suction as well as delivery side, or optionally a reciprocating tube type valve operated by a hydraulic cylinder herein after called as the gate valve cylinder. f. A no. of high pressure hoses to connect the working ports of all the hydraulic cylinders. g. A feed hopper on the suction side of the pumping cylinder having a mechanically driven agitator, h. A simple Directional control valve to operate or stop the strokes of the drive cylinder. i. A suitable grade hydraulic oil filled in the entire hydraulic circuit and the cylinders. j. A suitable capacity water tank between the pumping cylinder and the receiving cylinder meant for wash out & lubrication of the rubber piston in each stroke. k. Set of flow control valves in the slide gate lines & cross safety relief valves and anti-cavitations valves on both high pressure & low pressure sides.

I. A towable steel fabricated trolley with wheels on which the pump is mounted. m. A tapered pipe at the end of the delivery valve to accommodate the widely available pipeline dia. n. Mechanical stabilizers attached to the trolley, o. Safety covers on the moving parts. p. A cabled remote having simple functions on it, for the operation of the pump in case of solenoid operated directional control valve. q. An optional small air-compressor for cleaning the delivery line after pumping operation is over. r. A suitable capacity pressure accumulator to accommodate the differential volume of oil especially when the pump is operated in NEUTRAL. The capacity of the accumulator depends upon the head end & rod end differential volumes.

[005.001] Novelty of the Invention : The apparatus is adopted with following novel features which are radically different & never used in any of the prior arts available. a. Elimination of conventional hydraulic Pump: Almost all the modern concrete pumps available today use hydraulic pumps. However this invention completely eliminates the use of conventional hydraulic pump and makes the machine a very simple apparatus. The hydraulic oil is circulated in a closed loop & does not even require a hydraulic tank when the volume calculations are precisely made. b. Use of simple double acting hydraulic cylinder as a source of hydraulic power : The invention uses a double acting hydraulic cylinder as a source of fluid power replacing a conventional hydraulic pump. The use of double acting hydraulic cylinder results in huge techno-commercial advantage as cylinders are widely available in various sizes and are much cheaper compared to conventional hydraulic pumps. Which can be even replaced & serviced at regular intervals. c : Mechanical Drive but hydraulic operation : Unlike the direct driven mechanical reciprocating pumps, the said invention uses fluid power generated by a rotary mechanical drive. This enables the user the reversal of direction as well as frequent stoppage in Neutral which was not at possible with a direct driven mechanical pump. The said invention thus brings together the simplicity of the mechanical drive and the advantages of hydraulic operation. d . Use of rotary motion of the prime mover to regulate the gate valves in connection with the reciprocating piston: The simple rotary movement of the reduction gearbox flywheel is not only responsible for the reciprocating piston but also regulates the gate valves in connection with the movement of the reciprocating piston. This is simply because the gate valve shaft diameter is kept smaller compared to the reciprocating piston thereby giving priority to the gate valve operation which is further controlled by additional flow control valves. Thus the gate valve operation is self timed rather than having a separate timing circuit. e : Multiplication of reciprocating force & adjustable stroke-length : The said invention enables to have a much larger force for the pumping action simply by using a smaller diameter driving piston and a larger diameter driven piston. It is similar to using a hydraulic gearbox to multiply the pushing force. f : Change of no. of strokes per minute : The said invention very uniquely enables the user to change the working strokes per minute by simply changing the rpm. The rpm here represents the no. of strokes per minute. Alternatively the invention also enables the user to change the no. of working strokes simply by using a variable speed transmission. g : Mechanical reversal of direction : The available prior art concrete pumps use a variety of methods for reversing the reciprocating piston, which make the operation very complex. Some of the methods include limit switches, hydraulically operated pilot controlled servo-pistons which change the swash plate direction to reverse the reciprocating piston. However this invention successfully eliminates all the said mechanisms simply by using the to & fro motion of the hydraulic cylinder, which is forcefully operated by the continuous rotary mechanical motion of the reduction gearbox fly-wheel. The fly-wheel also adds to the efficiency due to its inertia. 6.00] CONSTRUCTION, WORKING & DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS ENCLOSED: CONSTRUCTION :

[006.01] "Hydraulically operated but mechanically driven & mechanically reversed simple Concrete Pump" is hereinafter described with reference to the drawings enclosed. PI. refer to the fig. No. which shows the working Diagram of "Hydraulically operated but mechanically driven & mechanically reversed simple Concrete Pump".

[006.02] A prime mover either an internal combustion engine or an electric motor(1) coupled to a suitable capacity high ratio reduction gearbox (2) with a off-center drive (3) to the Main Cylinder (4) which is connected to the Drive cylinder (5) with the help of hydraulic hoses A & B. The Driving cylinder operates the rubber piston (6) in the pumping cylinder (7). The pumping cylinder is provided with a slide gate valve system (8) which is operated by a hydraulic cylinders (10) and (11).

[006.03] WORKING OF THE SAID "Hydraulically operated but mechanically driven & mechanically reversed simple Concrete Pump" : Working : The Prime mover (1) is coupled with a heavy duty high torque reduction gearbox (2) wherein the prime mover rotation speed is highly reduced by increasing the torque. The output rpm of the said reduction gearbox represents the no. of working & suction strokes of the pumping cylinder(s).

1. The prime mover (1) starts & imparts rotary motion to the reduction gearbox (2) the off -centre drive (3) causes the main cylinder (4) piston to move to and fro. When the main cylinder piston (4A) moves to the right, it causes displacement of the oil through the hose (A) to the receiving cylinder (5). Because of this displacement, the receiving cylinder piston is forced forward. Which is the forward working stroke. . Thus typically the output rpm of the reduction gearbox represents the no. of forward strokes in a minute. It is possible to have a multi-geared reduction gearbox wherein the no. of strokes can be changed depending upon the mix and distance. Alternatively the number of working strokes can be simply changed by changing the rpm of the prime mover. Since the hose A is pressurized because of the displacement, it also provides pressure to operate the slide gate valves system (8). As the forward stroke starts, the displaced oil starts closing the slide gate valve on the suction side at the same time it starts opening the slide gate valve on the delivery side. The piston 5A of the said Drive cylinder is pushed forward which in turn pushes the rubber piston (6) forward in the pumping cylinder (7). As the off -centre point (3) comes diagonally opposite, the forward stroke of the drive cylinder is completed and the reverse stroke starts when the off-center point (3) moves further. The difference in cross section areas of the pistons (4A) and (5A) determines multiplication or division of the force and also the increase & decrease in the stroke length of the drive cylinder. Individual flow control valves are used to fine tune the working of the slide gate valve, which are not shown in the diagram. The said hydraulic cylinders used are alternatively provided with piston having piston rings to have better sealing at high pressure.

[006.04] The above mechanism can be used alternatively with a variety of gate-valve designs like S tube or ball valves, etc to control the gate valve operations.

[006.05] Other aspects of the invention will become apparent by consideration of the accompanying drawing and their description stated above, which is merely illustrative of a preferred embodiment of the invention and does not limit in any way the nature and scope of the invention.

Figure 1 illustrates the said "PRIOR ART NO. 1" in accordance with the present addition as described in this patent application;

Figure 2 illustrates the said "PRIOR ART NO.2" in accordance with the present addition; Figure 3 illustrates a very common hydraulic circuit currently used for concrete pumps called the "PRIOR ART NO. 3"

Figure 4 & 5 illustrates the said "Working Diagram" in accordance with the present invention; Ho j tVEie. THC H -VJ>*AU LIC ci fcc-o iTJ 1 TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE :

[007.001] The said invention uses a normal double acting hydraulic cylinder which replaces a conventionally available hydraulic pump which reduces the cost of the equipment as various types of double acting cylinders are available off the shelf in various sizes at comparatively very low capital costs compared to the conventional hydraulic pump.

[007.002] Also the said invention, the reversing action is achieved mechanically rather than using a servo-piston circuit, which again reduces the running & capital cost.

[007.003] The use of high torque low speed reduction gearbox results in very high mechanical efficiency & optimum utilization of power available when compared to the normal hydraulic pump driven system, allowing the prime-mover to be operated at low rpms typically from 960 to 1440 for electrical drives & from 1500 to 1900 for internal combustion engines resulting in huge saving of fuel. Typically with direct engine drives, the optimum torques are obtained during these speeds. Unlike the conventional hydraulic pumps which are operated at higher rpms to achieve larger flows.

[007.004] The present invention therefore results in following tech no- commercial advantages.

1. It lowers the cost & lead time of manufacturing due to its very simple operation. 2. It also enables the manufacturer to use all the components which are already available in the market and drastically reduces in-house machining and manufacturing process.

3. It eliminates the use of conventional hydraulic pump as it uses a simple double acting hydraulic cylinder to generate the reciprocating force and hence reduces the capital cost by huge margin.

4. It enables the manufacturer to have various capacities of pumps by having multiple combinations of the cross-sectional areas of the pistons of the main & the drive cylinders.

5. It also enables the end user to change the number of working strokes simply by adjusting the engine rpm or having a variable speed reduction gearbox. This feature is highly useful as the strokes can be changed according to the mix & the distance.

6. The mechanical drive results in very high mechanical efficiency. Further the displaced oil remains in the closed loop increasing the efficiency further.

7. The invention thus reduces the cost of capital investment for the end user by a huge margin.

8. The invention enables the manufacturer to make the pumps in various sizes & capacities by using the same or different power input & cylinder combinations.

9. Technically, the use of heavy duty high ratio reduction gearbox means a very high input torque which operates the main cylinder. Which in turn enables use of heavy duty hydraulic cylinders having huge oil displacements per minute.

10. Since the pump itself regulates the reversal of direction by successfully eliminating the sensors or limit switches or separate hydraulic circuits and servo pistons to change the swash plate direction, it makes the invention a very simple self regulating device having huge commercial advantages over sucn systems.

[007.05] While considerable emphasis has been placed herein on the components and component parts of the Dreferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the basic principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.