US 3820762 A
Description (OCR text may contain errors)
United States Patent [191 Bostriim et al.
[ 1 June 28, 1974 1 MOBILE CONCRETE STATION  Inventors: Sture Bostriim, Umea; Gert Nordstrom, Sormjole, both of Sweden  Assignee: Robacks Medaniska Verkstad Bostrom & Soner, Umea, Sweden  Filed: June 20, 1972  Appl. No.: 264,651
 Foreign Application Priority Data June 23, 1971 Sweden 8213/71  US. Cl 259/154, 259/159 A, 259/160, 259/ 161  Int. Cl B011 5/42  Field of Search 259/154, 159 A, 160, 176, 259/177,183,l53, 161,162,163
 References Cited UNITED STATES PATENTS 2,344,228 3/1944 Barber 259/159 A X Paulus et al. 259/159 A X Ross et a], 259/154 X 5 7] ABSTRACT A mobile or movable concrete station consists of several separate interconnectable units including an aggregate weighing unit, a cement silo unit, a belt conveyor unit and a concrete mixer unit with a cement scale vessel arranged in connection to the discharge end of the aggregate weighing unit for adding weighed cement to the aggregate material at the starting end of the conveyor unit which is adapted to connect the aggregate weighing unit with the concrete mixer unit. Each of the units in the concrete station is mounted on one or more wheeled carriages so that each unit individually or coupled in pairs can be moved by means of a traction vehicle or by railway.
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MOBILE CONCRETE STATION This invention relates to a concrete mixing station or concrete station and, more precisely, to a mobile or movable such station, which is composed of several separate units comprising those functions which are necessary for concrete mixing, for example weighing and charging of aggregates and cement, addition of water in a proportion determined according to the mixing prescription used, and mixing of the ingredient sub stances.
Concrete is very widely used as a foundation or base tain extent also because of its relatively low price at least in relation to other comparable building materials. These properties of concrete and particularly its strength, however, depend largely on the weight ratio between the ingredient, substances in the concrete being accurate in accordance with the mixing prescription. This requirement applies particularly to the weight ratio between water and cement, the so-called water-cement factor, which is of greatest importance for the strength of the concrete and for obtaining a concrete mass of high quality. Such concrete masses of high quality could heretofore be produced in a rational manner only in large stationary plants, so-called concrete factories, from which the concrete is delivered in ready state to the different building sites. Such permanent concrete factories usually are located only near densely populated areas and can service building sites located within a distance which from a transportation aspect is economically profitable and justifiable. At other building sites, i.e., such which are located at too large distances from a concrete factory to render the transport of the concrete economically profitable, the concrete usually is produced in so-called concrete mixers which substantially comprise a rotary container with emptying means. These concrete mixers have the advantage of being easily movable from one building site to the other, but theyhave such a small volume that several differentbatches have to be prepared even for a relatively small floor in a house structure. As these concrete mixers are charged manually, the probability is very small that each batch is given the quality intended, and that the different batches are given a uniform quality. Concrete mixers of this kind, therefore, cannot be used when the concrete has to meet very high requirements and when large quantities of concrete are required. Building sites located at a large distance from the nearest concrete factory and requiring large quantities of high-grade concrete, for example for large dam constructions, power stations and the like, either are to be supplied with concrete from the nearest concrete factory or aconcrete factory is to be erected at the building site in'question which after completed work normally is to'bedismantled. Of these two alternatives usually is chosen that which is economically most profitable, but also this alternative involves large costs and renders the building work substantially more expensive.
The present invention has, therefore, as its object to produce aconcrete station which shows the advantages of the small concrete mixer with respect to movability and the advantages of the fully automatic permanent concrete factory with respect to the production of highgrade concrete in large quantities at lowest possible cost, which quickly can be erected without concrete foundation and mobile cranes, with the help only of such vehicles which always operate on building sites of the type in question, such as for example mechanical loaders of the type rear loader and the like, and which can be transported on road or on rail. This object is achieved in that the invention has been given the characterizing features defined in the claims.
The invention is described in greater detail in the following, with reference to the accompanying drawings, in which FIG. 1 is a plan view of an embodiment by way of example of the concrete station according to the invention erected for operation at the site and comprising five different basic units,
FIG. 2 is'a lateral view of the concrete station shown in FIG. 1,
FIGS. 3 and 4 are a plan view and, respectively, a lateral view of the first unit comprised in the concrete station, viz, a weighing unit for aggregates and cement,
FIG. 5 is a section through this first unit substantially along the line VV in FIG. 4,
FIG. 6 is a lateral view of the second unit comprised in the concrete station, viz, a cement storing or silo unit in transport position,
FIG. 7 shows this second unit in operating position or in the position shown in FIGS. 1 and 2,
FIG. 8 is a plan view of the third unit comprised in the concrete station, viz, a conveying unit,
FIG. 9 shows this third unit in a lateral view and in operating position or in the position shown in FIG. 2, the transport position being marked schematically by dash-lines,
FIG. 10 shows a detail of the conveying unit, more precisely a means for feeding cement from a cement scale vessel and admixing this cement to the aggregate material on the conveyor,
FIG. 11 is a lateral view of the fourth unit comprised in the concrete station, viz, a concrete mixer unit in transport position,
FIG. 12 shows this fourth unit in operating position, i.e., in the position shown in FIG. 2, and
FIGS. 13 and 14, finally, are a lateral view and, respectively, a view seen from above in section of the fifth unit comprised in the concrete station, viz, a control unit.
The embodiment of the mobile concrete station ac- I cording to the invention, as shown in the drawings, comprises five different units designated generally by 1, 2, 3, 4 and 5 and defined in the same order as aggregate and cement weighing unit, cement storing or silo unit, conveying unit, concrete mixer unit-and control unit, which latter unit however is not absolutely necessary as it may advantageously be builtin. in any of the other units. In addition to said units there is provided a hydraulic unit, though not shown in the drawings, which comprises an electromotor, a pump, an oil tank containing all oil required for controlling the movement of the different units from transport position to operating position, two manuallyoperated four-way valves and oil pressure hoses with quick-couplings for connecting if necessary the hydraulic unit to anyone of the different units. If the concrete station is intended for operation in areas where there is risk of freezing, the concrete station also may include a unit comprising a boiler of optional type mounted in an insulated carriage with a hot-water tank, pump and oil tank containing fuel oil for firing the boiler.
According to the invention each unit comprised in the concrete station is built up upon a carriage provided with a detachable wheel equipment, so that each unit individually, or coupled in pairs or more units, can be pulled or pushed by a traction vehicle of truck, tractor or similar type. The wheel equipment for each such carriage is such that it can be used for anyone of the units comprised in the concrete unit, with the exception however of the control unit 5 (FIGS. 13 and 14) which preferably is of conventional caravan type comprising an insulated control room 6 provided with radiators, in which room a control table 7 with weighing and measuring instruments, control levers and flow sheet, and the electric center with fuses and motor switches are arranged. Said carriage is provided on its outside with connections 9 under roof protection for the connection of the ingoing and outgoing lines from and to the different units and of the mains voltage.
The first one of the different units to be comprised in the concrete station according to the invention is, as mentioned above, the aggregate and cement weighing unit designated by 1 in FIGS. 1 and 2 which is shown in greater detail in FIGS. 3 to 5. This unit, like the other ones, is built up on a carriage 10 provided with four wheels 11 of which each can be detached in a simple way by drawing the wheel axle out of its bearing bushing, and with a pull rod 12 which together with the front wheel pair is pivotally supported at the carriage for steering the same. The carriage further is provided with built-in jacks indicated schematically at 13. By means of said jacks and of trestles 14 adapted for direct placement on the ground, the carriage can be lifted rapidly off the ground and be blocked up to a level with the wheels freely suspended or removed.
The carriage 10 is provided with two relatively thick sides 15, above which a number of bins 16 for aggregate material are detachably arranged. The bins are filled with aggregate material preferably direct from a truck which, however, presupposes an arrangement of ramps, or with the help of a loader which usually always is available on working sites of the type here concerned. The aggregate bins are emptied by means of double sector covers 17, which are operated by compressed air cylinders 18 controlled by solenoid valves of the four-way type and limit switches for indication and fine feeding, onto a weighing conveyor 19 located below the bins and between the sides of the carriage. Said conveyor 19 is provided with weighing troughs 20 having Z-shaped sides with double sealings to prevent the loss of weighed aggregate material during its transport on the weighing conveyor out of the aggregate and cement weighing unit 1. The weighing conveyor is suspended at the aggregate bins by means of chains, shroud screws and electronic weighing transmitters. These details are only schematically shown and designated generally by 21 in FIGS. 3-5. When the weighing conveyor has received 'the aggregate amount determined in accordance with the mixing prescription, this is recorded by the weighing transmitters, and the covers of the aggregate bins are closed manually or automatically while the weighing conveyor is started for unloading the weighed aggregate material.
On said carriage, in the discharge direction after the aggregate bins 16, there is further provided a cement weighing vessel 22 which like the weighing conveyor is suspended by means of chains, shroud screws and weighing transmitters at a pair of arms 23 projecting from the carriage. In the drawings said vessel is shown with a single cement intake 24 for charging cement from above, but, in other embodiments it may be provided with, for example, four separate intakes for charging cement from above from more than one cement storing container or silo at a time, and has an outlet 25 provided with a sliding damper which is operated by a compressed air cylinder controlled by a solenoid valve of the four-way type. When the cement weighing vessel 22 has received the cement amount determined in accordance with the mixing prescription used, this is recorded by the weighing transmitters which cause the supply of cement to be stopped automatically and the sliding damper to be opened with delay relative to the aggregate feed so that the weighed cement material can flow out of the vessel.
Below this outlet 25 and in connection to the discharge end of the weighing conveyor, a conveying belt 26 is provided which is included in the belt conveyor unit 3. Said conveyor unit, which is shown in greater detail in FIGS. 8 and 9, comprises a belt conveyor 29 of conventional type hingedly connected with a carriage 28 located below the belt conveyor, and is provided with two wheels 27 of the same type as at the aggregate and cement weighing unit 1, so that the wheels of one unit can be used in the other unit, and vice versa. Said carriage 28 also is provided with built-in jacks 30 by means of which in cooperation with the trestles 14 adapted for direct placement on the ground, the conveyor unit 3 can be blocked up to operating position in which the belt conveyor 3 is to align with the aggregate and cement weighing unit 1, and its end facing said unit is to be located in a plane below the discharge end of the weighing conveyor 19 so that the aggregate material discharged from the aggregate and cement weighing unit falls onto the conveying belt of the belt conveyor 3. The arrangement of the belt conveyor end facing the aggregate and cement weighing unit below the discharge end of the weighing conveyor preferably is brought about by excavating a hole in the ground possibly by means of a loader of conventional type.
Between the belt conveyor 29 proper and the carriage 28 a number of telescopic hydraulic cylinders 31 are provided by means of which the belt conveyor is pivoted upwards from the transport position shown by dash-lines in FIG. 9 to the operating position shown by fully drawn lines after the carriage has been blocked up in the manner described. This unit 3 is further provided with a special loading box 32 for cement material which in operating position of the unit is located directly below the outlet 25 of the cement scale vessel 22. Said loading box, as appears more clearly from FIG. 10, has the form of a funnel with an obliquely cut discharge opening 33 directed in the feed direction of the conveying belt 26. In front of this opening and directly above the conveying belt 26, a plough-shaped body 34 is provided which has a lower surface 35 extending substantially in parallel with the conveying belt, and parallel wings 36 extending past said discharge opening 33. The object of said body is to plough the cement down into the aggregate material in order to prevent dust development and loss of material. The belt conveyor 29 further should be provided with a roof-superstructure 37 to protect the conveyed material against rain, wind etc., as shown specially in FIG. 10.
Cement is supplied to the cement scale vessel 22 via a conveying or cement screw 38 from the cement storing or silo unit designated by 2 in FIGS. 1 and 2 and shown in greater detail in FIGS. 6 and 7. Said unit comprises substantially a silo 39 provided'with a ladder 40. In transport position, i.e., in the position shown in FIG. 6, the silo is supported on a rear carriage 41 and a front carriage 42 with pull rod 43 which together with the wheels 44 of the front carriage is pivotally mounted to render possible its steering. The wheels 44 of the front carriage and also the wheels 44 of the rear carriage are of the same type as in the two aforementioned units 1 and 3. The rear carriage 41 comprises a rectangular underframe 45 which adjacent its corners is provided with built-in jacks 46 by means of which and of the trestles 14 adapted for placement directly on the ground said unit 2 can be blocked up, and with four inclined stay members 47 preferably stayed diagonally of which the rear members are hingedly connected with the silo by means of studs 48 arranged in bushings in the stay members 47 and in the side surface of the silo. The front stay members 47 are also connected with the silo by means of studs 49 which are removably arranged in bushings in the stay members 47 and in the silo side surface. The silo is provided, in addition to said bushings, with two further bushings which are arranged diametrically and designated by 50 in FIG. 6. The silo, thus, is supported in transport position on the front carriage 42 which is detachable, and on the rear carriage 41 which is connected with the silo only by said studs.
The rear carriage 41 is further provided with two telescopic hydraulic cylinders 51 which are hingedly mounted on the underframe and on the lower surface of the silo on both sides of the funnel-shaped emptying neck 52. The forward studs 49 having been removed and possibly also the front carriage which, however, can remain in place, the silo can by means of said hydraulic cylinders be folded upwards about the swing axle formed by the rear studs 48, from the transport position shown in FIG. 6 to operating position shown in FIG. 7, in which position the removed studs 49 are inserted into the bushings of the stay members and into the bushings 50 on the silo proper, so that the silo is locked in its folded-up or operating position. After the silo has been erected to operating position, it is filled with cement through a charging pipe 53, and the cement screw 38 is mounted in place for transferring cement from the silo to the cement scale vessel 22. The silo should further comprise a dust-collecting filter and a capacitive level indicator.
The concrete station according tothe invention may include more than one cement silo unit 2, though this is not shown in the drawings, and at maximum as many as there are charging apertures 24 in the cement scale vessel 22. In the latter case, i.e., with four cement silo units, the units should be arranged in a fan shaped pattern on both sides of the belt conveyor unit 3.
The concrete station according to the invention includes further, as mentioned, a concrete mixer unit 4 which is located after the belt conveyor unit 3 and shown in greater detail in FIGS. 11 and 12. Said unit comprises a conventional concrete mixer 54 of some suitable make which is mounted on a foundation 55. The foundation for the concrete mixer 54 is supported on a rear carriage 56 and a front carriage 5.7 which are provided with two detachable wheels 58 each being of the same type as the wheels for the other units 1, 2 and 3 comprised in the concrete station. The front carriage 57 is further provided with a pull rod 59 placed between the wheels and adapted to be detached like the wheels and together with the wheels be pivoted for steering the unit. In the position shown in FIG. 11, the transport position, the rear carriage 56 as well as the front carriage 57 are in a substantially horizontal position and by means of a number of studs 60, 61, for example three studs on each side, fixed and locked in this position relative to the foundation 55. Between each carriage 56, 5'7 and the foundation 55 a number of telescopic hydraulic cylinders 62 are hinged, which are only schematically indicated in FIGS. 11 and 12. By means of these hydraulic cylinders the front carriage and the rear carriage rolling on the respective wheels can after the studs 61 have been removed, be pivoted about the studs 60 arranged on both sides and up into the operating position shown in FIG. 12, in which the carriages 56, 57 which in this position act as legs for the foundation 55 are locked by means of the studs 61. Thereafter the unit is blocked up by help of jacks 63 builtin in each carriage and of the trestles 14. In this position, the operating position, the foundation 55 should have been lifted up to such a level that a truck, tractor or another loading vehicle can be driven below the foundation and there receive the prepared concrete from the concrete mixer 54 which in a conventional manner is provided with a discharge funnel 65. This unit further should comprise a pressurized water tank 64 and necessary measuring equipment to render possible an automatic mixing process and measuring equipment for receiving the material fed by the conveying unit 3, as well as means for adding the determined water amount tothe material charged into the mixer.
As is evident from the aforesaid, each unit comprised in the mobile or movable concrete station according to the invention is mounted on a carriage, so that the units without difficulty can be individually pulled by a truck or be transported by railway from one working site to another. At the arrival to a new working site, in order to position the concrete station as rapidly as possible the units according to the embodiment shown in the drawings with a separate control. car 5 should come in the order as follows: concrete mixer unit 4, belt conveyor unit 3, cement silo unit 2 and aggregate and cement weighing unit 1. The control unit or car 5 need not come in before or after some special unit. This applies to some extent also to the cement silo unit or units, particularly if there is plenty of space, but it should be inserted after the belt conveyor unit 3.
At first, th concrete mixer unit 4 is driven or backed to the intended place of erection. The hydraulic unit for control of the hydraulic cylinders included in the different units should accompany this unit or come in after it so that the hydraulic unit can be connected immediately for lifting the concrete mixer unit 4 to operating position in which the mixer is blocked up by means of the jacks and four trestles. During this time the belt conveyor unit 3 is moved in and aligned with unit 4 and blocked up. Thereafter the hydraulic unit is switched in for lifting the belt conveyor into operating position in which this unit is pushed over the charging funnel 65 of the concrete mixer 54. At this stage the control unit 5' can have been blocked up, so that the work of switching in and connecting the different lines can be commenced. When the belt conveyor unit 3 is in place, preferably the cement silo unit 2 is positioned because its position in relation to the units already blocked up is determined by the loading box 32 on the unit 3. After its blocking-up, the hydraulic unit can be connected to the telescopic hydraulic cylinders 51 of the unit 2 for folding the silo 39 proper upwards into operating position in which it is locked in the manner described. Thereafter the aggregate and cement weighing unit is inserted so as to align with the units 3 and 4 and so that the cement scale vessel 22 is situated directly above the loading box 32 of the conveyor 3 and now this unit 1 can be blocked up. After the cement screw 38 has been mounted in its place between the silo 39 and the cement scale vessel 22, the weighing conveyor has been released from its locked position, and all lines have been switched in and connected, the concrete station is ready for operation. Before that, of course, the silo 39 must have been filled with cement and the bins 16 been filled with aggregate.
The present invention is not restricted to what is described above and shown in the drawings, but can be modified in many different ways within the scope of the claims.
What we claim is:
1. A mobile or movable concrete station which is composed of several separate interconnectable units performing the functions required for mixing highgrade concrete including the weighing and charging of aggregate material and cement, the addition of water in a proportion determined by the mixing prescription being used, and the mixing of the ingredient substances, said mobile station comprising as separate units at least one aggregate weighing unit, at least one cement silo unit, a belt conveyor unit, and a concrete mixer unit; said aggregate weighing unit including a cement scale vessel disposed adjacent the discharge end of said aggregate weighing unit for adding weighed cement to the aggregate material at the starting end of said conveyor unit; said conveyor unit being adapted to connect said aggregate weighing unit with said concrete mixer unit; each of said separate units being mounted on at least one wheeled carriage so that each unit individually or coupled in pairs can be transported by means of a traction vehicle or by railway; at least the cement silo unit, the belt conveyor unit, and the concrete mixer unit being provided with telescopic hydraulic cylinders adapted to move each said unit from a transport position into an operating position; the silo portion of said cement silo unit resting in its transport position on a front carriage to which it is detachably connected and on a rear carriage to which it is connected by means of studs which form a swing axle about which said silo portion can be erected by means of said hydraulic cylinders from its transport position into its operating position; said concrete mixer unit comprising a foundation connected to both a front carriage and a rear carriage each of said mixer unit carriages being hingedly connected to said foundation at one end thereof and having wheels at its other end, the hydraulic cylinders for moving the mixer unit from its transport position to its operating position being arranged between said foundation and said carriages and being operative, when actuated, to cause the mixer unit carriages to move from a substantially horizontal trans port position to a raised operating position by a rolling of the carriage wheels about the respective hinged connections between said carriages and said foundation.
2. A mobile or movable concrete station which is composed of a plurality of separate interconnectable units performing the functions required for mixing high-grade concrete including the weighing and charging of aggregate material and cement, the addition of water in a proportion determined by the mixing prescription being used, and the mixing of the ingredient substances, said mobile station comprising as separate units at least one aggregate weighing unit, at least one cement silo unit, a belt conveyor unit, and a concrete mixer unit; said aggregate weighing unit including a cement scale vessel positioned adjacent the discharge end of said aggregate weighing unit for adding weighed cement to the aggregate material at the starting end of said conveyor unit; said conveyor unit being adapted to connect said aggregate weighing unit with said concrete mixer unit, the starting end of said conveyor unit facing said aggregate weighing unit and being provided with a loading box for receiving cement from said cement silo unit, said loading box being provided with a plough-shaped body for ploughing cement down into the aggregate material on said conveyor unit; each of said separate units being mounted on at least one wheeled carriage so that each unit individually or coupled in pairs can be transported from one location to another by means of a traction vehicle or by railway.
3. A mobile concrete station comprising a plurality of separate interconnectable units performing the functions required for mixing high-grade concrete, including the weighing and charging of aggregate material and cement, the addition of water in a proportion determined by the mixing prescription being used, and the mixing of the ingredient substances, said mobile station including at least one separate aggregate weighing unit having a plurality of bins for storing different sized aggregates, said bins being located above a weighing conveyor comprising a portion of said aggregate weighing unit and operative to weigh and charge the aggregates being weighed, said mobile station further including at least one separate cement silo unit, a separate belt conveyor unit, and a separate concrete mixer unit; each of said four separate units being mounted on at least one wheeled carriage to enable said carriage mounted units to be transported individually or in an interconnected relationship from one location to another; each of said units being provided with lifting means for lifting and blocking up said unit on ground supported trestles; said belt conveyor unit being disposed between said aggregate weighing unit and said concrete mixer unit in alignment therewith, said cement silo unit being disposed to the side of the aligned aggregate weighing and belt conveyor units and being connected, by means of a cement screw, to a cement scale vessel positioned adjacent the discharge end of said aggregate weighing unit, said cement scale vessel being operative to weigh cement from cement silo unit and to supply the cement so weighed to said aggregates at the starting end of said belt conveyor unit for delivery by said belt conveyor unit to said mixer unit.
4. The concrete station of claim 3 wherein said lifting means comprise jacks mounted on each one of said wheeled carriages.
5. The concrete station of claim 3 wherein said cement scale vessel is suspended from the rear end of said aggregate weighing unit.
6. The concrete station of claim 3 wherein at least said cement silo unit, said belt conveyor unit, and said concrete mixer unit are each provided with telescopic hydraulic cylinders for shifting said units from a transport position into an operating position.
7. The concrete station of claim 6 wherein the silo portion of said cement silo unit rests in its transport position on a front carriage to which it is detachably connected, and on a rear carriage to which it is connected by means of studs, at least some of said studs forming a swing axle about which said silo portion can be erected by means of said hydraulic cylinders from a generally horizontal transport position into a generally vertical operating position.
8. The concrete station of claim 6 wherein said concrete mixer unit includes a foundation for supporting the concrete mixer, said mixer unit further including a front carriage and a rear carriage each of which is hingedly connected to said foundation at one end of the carriage and each of which carries wheels at its other end, said hydraulic cylinders for moving the mixer unit from its transport position to its operating position being located between said foundation and said carriages and being operative to cause the carriages to roll between a substantially horizontal transport position and a raised operating position.
9. The concrete station of claim 3 wherein said belt conveyor unit, adjacent the end thereof facing the aggregate weighing unit, is provided with a loading box for receiving cement from the cement silo unit, said loading box being disposed below the cement silo unit and being provided with a plough-shaped body for ploughing cement down into the aggregate material on said conveyor unit 10. The concrete station of claim 3 further comprising a wheeled control car equipped with a control table and with an electrical center, and means for connecting said car to each of said units for controlling the different functions of said units from said control car.