US3128711A

US3128711A - Apparatus for transporting pasty materials

Info

Publication number: US3128711A
Application number: US24529A
Authority: US
Inventors: Voigt Otto; Presch Martin
Original assignee: Pintsch Bamag AG
Current assignee: Pintsch Bamag AG
Priority date: 1959-04-25
Filing date: 1960-04-25
Publication date: 1964-04-14
Anticipated expiration: 1981-04-14

Description

April 14, 1964 o. VOIGT ETAL 3,128,711

APPARATUS FOR TRANSPORTING PASTY MATERIALS Filed April 25, 1960 2 Sheets-Sheet 1 V INVENTOQ' 21% a Vie a April 14, 1964 o. VOlGT ETAL 3,123,711

APPARATUS FOR TRANSPORTING PASTY MATERIALS Filed A ril 25, 1960 2 Sheets-Sheet 2 INVENTOR (am \/n Mex/w. 0K

United States Patent Ofiice 3,128,711 Patented Apr. 14, 1964 Bamag Aktiengesellschaft, Berlin, Germany, and Ludwig Rexroth, Lohr (Main), Germany Filed Apr. 25, 1960, Ser. No. 24,529 Claims priority, application Germany Apr. 25, 1959 7 Claims. (Cl. 103-45) The present invention relates to apparatus for transporting pasty materials such as non-solid concrete.

More particularly, the present invention relates to a pumping apparatus capable of pumping such a pasty material.

With apparatus of this type it is necessary for the structure such as the pump to carry out a plurality of different operations during each cycle, and with the present-day state of the art it becomes necessary to stop the operations whenever foreign bodies or the like cause obstructions to the cyclically moving elements. Moreover, it is often desirable to provide a structure which makes it possible to easily and conveniently inspect the parts so as to carry out repairs or maintenance as desired, and this requirement also presents difliculties with conventional structures of the above type. Moreover, occasions arise when it is desired to change over from automatic to hand operation, and this result also is not readily achievable with the conventional structure.

One of the objects of the present invention is to provide an apparatus of the above type which is automatically controlled in such a way that while it will automatically carry out the successive operations of each cycle it also will not necessarily stop operating when obstructions are encountered but will instead automatically move on to the next operation even though the immediately preceding operation has not been completed because some unforeseen force or object has prevented the immediately preceding operation from being completed. Thus, with the invention the operations will continue even though some particular operation for some reason has not been carried through completely.

Another object of the present invention is to provide a structure of the above type which can be very easily operated in such a way that parts of the structure which must be maintained or repaired from time to time can be rendered easily accessible for inspection and maintenance or repairs.

It is furthermore an object of the present invention to provide a structure of the above type which has controls which easily allow the structure to be converted from automatic to hand operation and vice versa, so that certain special operations can be carried out by hand as desired.

An additional object of the present invention is to provide a structure of the above type which operates very smoothly and with a minimum amount of shocks or the like so that all of the structure will have a long life of efficient operation.

With the above objects in view the invention includes, in an apparatus for transporting a pasty material such as non-solid concrete or the like, a pump means for pumping the pasty material, this pump means repeatedly carrying out an operating cycle during which the pump means performs a plurality of operations. A hydraulic means cooperates with this pump means and moves through a plurality of positions in which the hydraulic means drives the pump means through its several operations, respectively, and this hydraulic means includes at least one fluid conduit in which the fluid pressure increases at the end of each of the operations of the pump means. According to the present invention there is provided a moving means which cooperates with the hydraulic means and responds to the increase in the fluid pressure for auto matically moving the hydraulic means from one position to the next.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 schematically illustrates one structure according to the present invention; and

FIG. 2 schematically illustrates a second embodiment of the invention, the embodiment of FIG. 2 differing from that of FIG. 1 in that with FIG 2 one of the pistons is limited in its movement by a hydraulic stop structure while in FIG. 1 the stop structure is purely mechanical.

Referring now to FIG. 1, the structure illustrated there in includes a pump means for pumping a pasty material such as non-solid concrete or the like. This pump means includes the pump cylinder 1 and the pump piston 2 which reciprocates in the pump cylinder 1. The piston 2 moves through its pressure stroke when it moves to the left, as viewed in FIG. 1, and through its suction stroke when it moves to the right, as viewed in FIG. 1. As may be seen from FIG. 1 a hopper 5 or the like is provided for the pasty material or the like which is to be transported by the structure of the invention. Also, it will be seen that a discharge conduit 6 communicates both with the pump cylinder 1 and with the hopper 5, the latter forming a supply means for supplying to the pump cylinder 1 the material which is to be transported from the pump cylinder 1 to the discharge conduit 6.

A valve means cooperates with the supply means 5 and the discharge conduit 6 for placing the supply means and discharge conduit alternately in communication with the cylinder 1. This valve means 3, 4 has a suction position where the discharge conduit 6 is closed and the supply means 5 is open so that material from the hopper 5 may then be sucked into the cylinder 1 during the suction stroke of the piston 2, and the parts are shown in this position in FIG. 1. The valve means 3, 4 also has a discharge position where it closes the supply means 5 and opens the conduit 6 so that when the piston 2 moves along its pressure stroke it will advance the material from the cylinder 1 into the discharge conduit 6.

As may be seen from FIG. 1, the valve means 3, 4 includes the housing 4 in which the valve member 3 is slidably guided. This housing 4 is provided with an opening communicating with the hopper 5 as well as with a second opening communicating with the discharge conduit 6, and when the slide valve member 3 is in its lower position indicated in FIG. 1 it closes the opening which communicates with the discharge conduit 6, so that in this position of the parts the opening which communicates with the hopper 5 is uncovered and the material can flow from the hopper 5 into the pump cylinder 1. The slide valve member 3 is movable from the illustrated suction position thereof up to a discharge position where it closes the opening which communicates with the hopper 5, so that in this position the opening of the slide valve hous ing 4 which communicates with the conduit 6 is uncovered and there is free communication between the conduit 6 and the pump cylinder 1.

A pair of double-acting hydraulic piston and cylinder means are provided for respectively driving the piston 2 and the slide valve member 3. The double-acting piston cylinder means 7, 8 is operatively connected with the piston 2, while the double-acting piston and cylinder means 9, 10 is operatively connected with the slide valve member 3 for operating the latter. Of course, the housing 4 of the slide valve member 3 extends through and is carried by the hopper 5 as well as the conduit 6 in the manner shown in FIG. 1. The double-acting cylinder and piston means 7, 8 includes a stationary elongated cylinder 7 and a piston 8 slidable therein, the piston 8 being fixed to the piston 2 by the elongated rod shown in FIG. 1, so that the piston 2 necessarily reciprocates with the driving piston 8. The double-acting hydraulic cylinder and piston means 9, includes the cylinder 9 and the driving piston 10 slidable therein, this piston 19 being connected through a suitable rod with the slide valve member 3 so that the latter reciprocates with the piston 10.

A pair of hydraulic conduits communicate with each of the cylinders of the pair of hydraulic piston and cylinder means, and thus as is shown diagrammatically in FIG. 1 the pair of

conduits

13 and 14 communicate with the cylinder 9 while the pair of

conduits

11 and 12 communicate with the cylinder 7. Thus, when fluid under pressure is delivered to the conduit 13 the piston 10 will move up, as viewed in FIG. 1, while when the conduit '14 receives fluid under pressure the piston 10 will move down so as to place the slide valve member 3 in the position illustrated in FIG. 1. When the conduit 11 receives fluid under pressure the piston 8 will advance to the right in the cylinder 7, as viewed in FIG. 1, so as to move the piston 2 along its suction stroke, while when the conduit 12 receives fluid under pressure the piston 8 will advance to the left, as viewed in FIG. 1, moving the piston 2 along its pressure stroke.

A second valve means 15 diagrammatically shown in FIG. 1 communicates with the several hydraulic conduits 11-14 for delivering fluid under pressure thereto according to a predetermined sequence as described below. This valve means 15 may take any known form of a four-way valve which in its several positions is capable of connecting a selected conduit to a source of fluid under pressure while simultaneously connecting the remaining conduits to the low-pressure conduit which returns the fluid to the reservoir from which it is derived. The valve means 15 takes, preferably, the form of a rotary four-way valve.

For a purpose which is described below, the right end of the pump cylinder 1, as viewed in FIG. 1, is open, and the length of the cylinder 7 is such that the piston 8 is capable of moving through a stroke whose length is more than the length of the cylinder 1 by an amount equal to at least and preferably somewhat more than the axial length of the piston 2.

A hydraulic pump means 18 which is in the form of any conventional oil pump, for example, which can have its operation regulated, communicates through a pressure conduit 16 with the valve means 15. This valve means 15 also communicates with a low-pressure return flow conduit 17 which discharges the hydraulic fluid into the reservoir 19 from which the pump 18 pumps the fluid through the pressure conduit 16 to the valve 15.

The rotary valve means 15 repeatedly carries out an operating cycle during which the valve 15 has the four positions shown schematically in FIG. 1. Thus, it will be seen that in position I the valve means 15 places the conduit 14 in communication with the pressure conduit 16 while the remaining conduits 11-13 communicate with the low-pressure return flow conduit 17. In this position of the valve means 15, the fluid under pressure which flows from the conduit 16 through the conduit 14 will enter the cylinder 9 to move the piston 10 down to the position illustrated in FIG. 1 where the slide valve member 3 closes the conduit 6 so that in this position of the parts the valve means 3, 4 has been placed in its suction position. The valve means 15 will then be moved automatically, in a manner described below, to its second position diagrammatically indicated in FIG. 1 as position 11, and in this position the pressure-conduit 16 is placed in communication with the conduit 11, while the conduits 12-14 all communicate with the return flow conduit 17, so that when the valve means 15 is in position II the fluid under pressure will enter the left end of the cylinder 7 to move the piston 8 to the right, as viewed in FIG. 1, and thus moves the piston 2 along its suction stroke so as to suck material from the supply means 5 into the pump cylinder 1.

Thereafter the valve means 15 is automatically moved to position III diagrammatically indicated in FIG. 1, and in this position the pressure conduit 16 is placed in C0111- munication with the conduit 13, while the

conduits

11, 12 and 14 communicate with the return flow conduit 17, so that in this position of the valve means 15 the fluid under pressure will flow through the conduit 13 into the lower end of the cylinder 9, as viewed in FIG. 1, so as to move the piston 10 upwardly in order to locate the slide valve member 3 in its upper, dischrage position where the discharge conduit 6 is uncovered and communicates with the pump cylinder 1.

Finally, the valve means 15 is automatically moved to position IV where, as is shown diagrammatically in FIG. 1, the pressure conduit 16 communicates with the conduit 12, while the

conduits

11, 13 and 14 all communicate with the return flow conduit 17, so that in position IV of the valve means 15 the fluid under pressure reaches the right end of the cylinder 7, as viewed in FIG. 1, and advances the piston 8 to the left, as viewed in FIG. 1, so as to move the pump piston 2 along its pressure stroke in order to transport the material from the cylinder 1 into the discharge conduit 6 from where the material is delivered to any desired location.

In accordance with the present invention the valve means 15 can be operated manually or automatically, and in order to effect the manual operation a handle 20 is fixed to and extends radially from the rotary valve member so that by engaging the handle 20 the operator can turn the valve 15 to any one of its four positions.

The automatic operation of the valve means 15 is derived from a moving means which includes a cylinder in which the piston 21 is slidable. This cylinder is adapted to receive fluid under pressure for advancing the piston 21 therein in a manner described below. A spring is placed in a position where it acts on the piston 21, as indicated in FIG. 1, to return the piston 21 to its lower starting position, as viewed in FIG. 1, when the fluid under pressure acting on the lower face of the piston 21, as viewed in FIG. 1 is relieved by placing the lower end of the cylinder in communication with the return flow conduit 17, as will be apparent from the description below. A suitable one-way drive 22 serves to transmit the upward movement of the piston 21, as viewed in FIG. 1, to the rotary valve member of the valve means 15. This means 22 can have any one of a number of suitable constructions. Thus, for example, the piston 21 may act through a suitable pawl and ratchet mechanism 22 on the rotary valve member of the valve means 15 for turning this rotary valve member from one position to the next during each pressure stroke of the piston 21, the pawl and ratchet mechanism or any other suitable one-way drive simply return to its starting position without turning the rotary valve member of the valve means 15 during the time that the spring which acts on the piston 21 returns the latter to its initial position.

A hydraulic control means is provided for controlling the operation of the moving

means

21, 22, and this bydraulic control means includes the slide valve 23 diagrammatically indicated in FIG. 1. This slide valve 23 includes a housing in which a slide valve member slides longitudinally, and the housing of the slide valve 23 is connected through a conduit 24 to the cylinder in which the piston 21 of the moving means slides, so that the fluid moves to and from the latter cylinder through the conduit 24. The housing of the slide valve 23 is also connected through the conduit 26 with the pressure conduit 16 downstream of the pump 18 but upstream of the valve means 15, and also a conduit 27 serves to connect the slide valve 23 with the low-pressure return flow conduit 17. The control valve means 23 has two positions I and II, and as is indicated diagrammatically in FIG. 1, in the position I the cylinder which receives the piston 21 is connected through the conduit 24 and the valve 23 to the conduit 27 so that in the illustrated position of the parts the piston 21 is back in its initial position and the fluid which engages the piston 21 is at the low return flow pressure. The control valve means 23 also has the operating position II where the fluid under pressure flows from the conduit 26 through the control valve means 23 to the conduit 24 to enter through the latter into the cylinder of the piston 21 so as to advance the latter for producing the movement of the valve means 15 in the manner described above.

The control valve means 23 is actuated by a simple hydraulic piston and cylinder means 28 shown diagrammatically in FIG. 1, and this means 28 includes a spring which returns the means 28 to its initial rest position, the spring acting through the means 28 on the slide valve 23 to maintain the latter in position I shown in FIG. 1. The valve 23 moves to position II only when a relatively high pressure acts on the piston and cylinder means 28 in a manner described below.

A detent device 29, diagrammatically illustrated in FIG. 1, is provided for releasably holding the valve 23 in either of its positions, and this detent device is released when the high pressure acts on the means 28 to move the slide valve from position I to position II, while after the valve means 15 has reached its next position any suitable device connected with either the one-way transmission 22, the piston 21, or the rotary valve member of the valve means 15 engages the detent 29 to release the latter S that the spring can return the slide valve 23 to position I thereof shown in FIG. 1 as soon as the valve 15 has reached its next position.

A manually operable valve means 31) is provided for optionally placing the entire organization either in position for automatic operation or in position for hand operation. The manually operable valve means 3% has the two positions I and II diagramamtically indicated in FIG. 1 where the valve means 30 is shown in the position for setting the apparatus to operate automatically. In this position it is seen that the hydraulic means 28 which actuates the control valve means 23 is connected through the valve 30 directly with the high-pressure conduit 16 upstream of the pump 18. When the valve 30 is manually moved to the position which sets the apparatus for manual operation, which is position II diagrammatically indicated in FIG. 1, the communication between the hydraulic drive 28 and the conduit 16 is interrupted so that the control valve 23 will not be automatically actuated and of course the moving

means

21, 22 Will also remain stationary at this time. Thus, with hte manually operable valve means 30 it is possible at any time to interrupt the operation substantially instantaneously, which is a considerable advantage with a structure as shown in FIG. 1.

Finally, the structure includes, as indicated in FIG. 1, a pressure-relief automatic overflow valve 34 which automatically opens when the pressure in the conduit 16 reaches an excessive value above a predetermined desired limit, so that in this Way it is not possible for the fluid pressure to become dangerously high and the fluid will automatically flow back to the reservoir 19 if for some reason the pressure rises above a predetermined maximum value.

The structure described above and shown in FIG. 1 0p erates in the following manner:

The parts are shown in the position where the valve means 15 is in position I so that the conduit 14 receives the fluid under pressure from the conduit 16, as explained above. Thus, the slide valve member 3 has been moved down to the position illustrated in FIG. 1 placing the valve means 3, 4 in its suction position. When the valve 3 reaches the end of its movement the valve housing 4 acts as a stop for the valve 3 and thus the piston 10 cannot move beyond the end position determined by the end of the movement of the sliding valve 3. However, the pump 18 still continues to deliver liquid under pres sure through the conduit 16, the valve 15, and the conduit 14 to the cylinder 9 on the upper side of the piston 10. Since the latter cannot move further the pressure in the

conduits

14 and 16 increases, and when this pressure has increased sufliciently it will act on the hydraulic drive 28 to shift the control valve means 23 in opposition to the spring which urges the latter to its rest position to position II where the fluid under pressure can flow through the conduit 26 and the valve 23 to the moving means for moving the piston 21 and actuating the one-way drive 22 to turn the rotary valve member of the valve means 15 from position I to position II. The movement of the valve means 15 to position II places the conduit 11 in communication with the conduit 16 so that the pressure drops suddenly and this enables the piston 21 to return to its initial position while at the same time the movement of the valve means 15 to the next position has released the detent 29 so that the spring of the control means 23 will return the latter to the position I indicated in FIG. 1, and thus the apparatus operates automatically to initiate the movement of the piston 8 and the piston 2 therewith along the suction stroke of the latter, after the valve means 3, 4 has been placed in its suction position shown in FIG. 1. The piston 2 continues along its suction stroke until it engages a stop member 35 in the form of a simple pin or bolt carried by the cylinder 1 and passing radially through the wall thereof into the path of movement of the piston 2 so as to limit the movement of the latter. Once the piston 2 reaches the stop 35 the pressure in the

conduits

11 and 16 will again build up since the pump 18 continues to operate, and thus the pressure will again reach a value sufliciently high to shift the control valve means 23 from position I to position II, and the moving means 21, 22 will thus be again actuated to move the valve 15 from position II to position III. In this latter position the conduit 16 communicates through the valve 15 with the conduit 13 so that the piston 10 moves to displace the slide valve member 3 to its discharge position, and the upper end of the cylinder 9 acts as a limit to the movement of the piston 10 in this case. Thus, when the piston 10 reaches its limit of upward movement, as viewed in FIG. 1, the pressure in the

conduits

13 and 16 will build up to a value suflicient to again actuate the control valve means 23 which will again place the conduit 26 in communication with the conduit 24 so as to actuate the moving means 21, 22 to automatically move the valve means 15 to position IV thereof. Now the fluid under pressure will flow from the conduit 16 through the valve means 15 to the conduit 12, and of course there is a drop in pressure which permits the moving means 21, 22 and the control means 23 to return to their initial positions. The fluid under pressure now moves the piston 8 and piston 2 therewith along the pressure stroke of the latter so that the pasty material in the cylinder 1 is discharged through the conduit 6. At the end of the pressure stroke of the piston 2 the piston 8 will reach the left end of the cylinder 7 and thus cannot move further so that the pressure again builds up in the conduit 16 to again automatically actuate the control means 23 and the moving means 21, 22 for turning the rotary valve member of the valve means 15, and this rotary valve member now moves from position IV to position I, so that the fluid under pressure now again flows from the conduit 16 through the valve 15 to the conduit 14 to return the valve member 3 to the position shown in FIG. 1, and the above cycle of operations is again repeated.

Any time it is desired to stop the operation of the apparatus the operator need only move the manually operable valve means from position I to position II, and if this is done while the piston 2 or the slide valve member 3 is moving, this movement will continue to the end of its stroke and then the apparatus will remain stationary.

It will be noted that with the structure described above if an obstruction such as a foreign body, for example, interrupts the movement of the slide valve member 3 or the piston 2, or obstructs the discharge conduit 6, the pressure will also build up so that even though the particular operation is not completed the structure will automatically move on to the next operation, and this in itself may be adequate to take care of the obstruction which may be shifted to a non-obstructing position without any interruption in the operations. On the other hand, at any desired time the manually operable valve means 31) may be moved to position II so that the structure can then be operated manually by manipulation of the handle 20, and this can be done in order to remove an obstruction which prevents proper operation of the slide valve member 3 or to remove an obstruction from the discharge conduit 6.

Moreover, from time to time it will be necessary to remove the piston 2 from the cylinder 1 so as to be able to inspect the pump means 1, 2 as well as to clean the same periodically and provide other maintenance, and for this purpose the stop means 35 is removed. Although only one stop pin 35 is shown in FIG. 1, any desired number of such stop pins may be provided. These pins are releasably held in position by any suitable releasable lock structure (not shown) or by removable wedge members or the like, and after the lock structure is released the stop or stop members 35 can be removed and the valve 15 manually placed in position II by manipulation of the handle 20 with the valve means 30 in its position 11, so that the fluid under pressure flows to the conduit 11 to displace the piston 8 to the right moving the piston 2 along its suction stroke. Because the right end of the cylinder 1 is open and because the length of the cylinder 7 is longer than the length of the cylinder 1 by somewhat more than the axial length of the piston 2, the piston 8 will now move through a longer stroke which will be sufficiently long to move the piston 2 out of the cylinder 1 so that both the piston 2 and the cylinder 1 are in this way rendered accessible.

The embodiment of FIG. 2 differs from that of FIG. 1 in that the structure of FIG. 2 includes a hydraulic stop means and additional hydraulic structure for controlling the hydraulic stop means. Thus, referring to FIG. 2 it will be seen that the manually operable valve means 30 is replaced by a manually operable valve means 31 which has the positions I and II which are identical with that of the valve means 30, While the valve means 31 has an additional position III. When the manually operable valve means 31 is placed in position III thereof, a conduit 32 which communicates with the right end of the cylinder 7 is placed through the manually operable valve means 31 in communication with the conduit 27 which leads to the return flow conduit 17. In the embodiment of FIG. 2, a non-return valve 33 is located between and communicates with the

conduits

12 and 32, this valve 33 permitting fluid to flow from conduit 12 to the conduit 32 but not from the conduit 32 to the conduit 12. Also, in the embodiment of FIG. 2 the conduit 12 does not communicate with the cylinder 7 in the manner shown in FIG. 1. Instead the conduit 12 communicates through the rear wall of the cylinder 7 with a conduit 36 which forms an extension of the conduit 12 and which terminates within the cylinder 7 at the point which is reached by the piston 8 when the piston 2 is at the end of its suction stroke, this piston 8 serving to close the open end of the conduit 36 when the piston 8 reaches this conduit.

In the illustrated example the piston 8 is formed with an axialbore which receives the conduit 36, so that when the piston 8 reaches 'the conduit 36 the liquid which surrounds the latter in the cylinder 7 is trapped between the piston 8 and the right end wall of the cylinder 7, as

viewed in FIG. 2, and thus this liquid acts as a stop for limiting the movement of the piston 8 and thus limiting the suction stroke of the piston 2. Since the oil or the like surrounding the conduit 36 and located between the piston 8 and the right end wall of the cylinder 7, as viewed in FIG. 2, is incompressible it acts as a stop providing automatically, in the manner described above the increase in pressure which automatically moves the valve means 15 to the next position.

On the other hand, if the manually operable valve means 31 has been moved to the position III thereof when the piston 8 moves to the right moving the piston 2 along its suction stroke, it will be seen that at this time the conduit 32 communicates with the return flow conduit 17, so that the oil or the like which surrounds the conduit 36 will at this time be free to flow out through the conduit 32, the valve 31, the conduit 27, and the conduit 17 to the reservoir 19, so that the piston 8 will now be able to continue its movement all the way to the right end of the cylinder 7, as viewed in FIG. 2, and thus in this position the piston 2 will become located outwardly beyond the cylinder 1 for the purposes described above. With this embodiment the manually operable valve 31 can be moved at any desired instant to cut off communication between the conduit 32 and the conduit 27, so as to stop the movement of the piston 8 and the piston 2 therewith when the piston 2 has reached a desired position with respect to the cylinder 1.

After the piston 8 has moved in this way through a longer stroke to locate the piston 2 beyond the cylinder 1, :the manually operable valve means 31 is placed in position II thereof, so that the conduit 32 no longer communicates with the conduit 27, and at this time the valve means 15 may be manually placed in position IV thereof so that the fluid under pressure will flow from the conduit 16 through the conduit 12 to the cylinder 7. Since the conduit 36 at this time is in the bore of the piston 8, the fluid under pressure will flow through the non-return valve 33 into the cylinder 7 to advance the piston 8 to the left, as viewed in FIG. 2, and the fluid flows through the non-return valve until the piston 8 moves beyond the conduit '36 so that the fiuid under pressure can now flow from the latter into the cylinder 7, and the non-return valve 33 returns to its closed position.

It should be noted that where in the embodiment of FIG. 1 an axial stop is located in the right end wall of the cylinder 7 to limit the movement of the piston 8, this axial stop when unlocked can be moved out of the cylinder 7 by the piston 8 itself.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of pumps differing from the types described above.

While the invention has been illustrated and described as embodied in pumps for pasty materials, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended Within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. Apparatus for transporting a pasty material such as non-solid concrete or the like, comprising, in combination, pump means for pumping the pasty material, said pump means repeatedly carrying out an operating cycle during which said pump means performs a plurality of operations; hydraulic means cooperating with said pump means and moving through a plurality of positions in which said hydraulic means drives said pump means through said operations, respectively, said hydraulic means including at least one fluid conduit in which the fluid pressure increases at the end of each of said operations; and moving means cooperating with said hydraulic means and responding to the increase in fluid pressure for automatically moving said hydraulic means from one position to the next, said pump means including a cylinder having an open end and a piston which moves toward said open end of said cylinder during a suction stroke of said piston, and said hydraulic means including a driving cylinder and piston with the driving piston of the hydraulic means connected to the piston of the pump means for reciprocating the latter piston, said hydraulic means also including a stop carried by one of said cylinders in the path of movement of the piston therein during the time when said driving piston moves said pump piston along its suction stroke for limiting the movement of both of said pistons, said stop being removable so that said drive piston can move through a stroke longer than the suction stroke of said pump piston to move the latter through the open end of said pump cylinder beyond the latter in order to give access to said pump piston and pump cylinder.

2. Apparatus for transporting a pasty material such as nonsolid concrete or the like, comprising, in combination, pump means for pumping the pasty material, said pump means repeatedly carrying out an operating cycle during which said pump means performs a plurality of operations; hydraulic means cooperating with said pump means and moving through a plurality of positions in which said hydraulic means drives said pump means through said operations, respectively, said hydraulic means including at least one fluid conduit in which the fluid pressure increases at the end of each of said operations; and moving means cooperating with said hydraulic means and responding to the increased fluid pressure for automatically moving said hydraulic means from one position to the next, said pump means including a pump cylinder and a pump piston, said pump cylinder having an open end toward which said pump piston moves when said pump piston moves along a suction stroke, said hydraulic means including a driving cylinder and piston, said driving piston being connected with said pump piston to reciprocate the latter and said driving piston moving during the suction stroke of said pump piston toward one end of said driving cylinder, said hydraulic means including an elongated conduit carried by said driving cylinder at said one end thereof coaxially with said driving piston and through which hydraulic fluid enters into said driving cylinder to move said driving piston in a direction which moves said pump piston away from said open end of said pump cylinder along the pressure stroke of said pump piston, said driving piston being formed with a bore which receives said conduit When said driving piston approaches said one end of said driving cylinder so that the fluid which surrounds said conduit acts as a stop to limit the movement of said pistons, and said hydraulic means including a manually operable means for relieving the pressure in the fluid surrounding said conduit when said conduit is received in said bore so that said driving piston can then move beyond the point Where it is stopped by the fluid surrounding said conduit through a stroke long enough to move said pump piston out of said pump cylinder through said open end thereof and beyond said pump cylinder to give access to said pump cylinder and said pump piston.

3. Apparatus for transporting pasty material such as non-solidified concrete and the like, comprising, in combination, a pump cylinder; a discharge conduit communicating with said pump cylinder; supply means communicating with said cylinder for supplying the latter with material to be pumped from said supply means into said cylinder and from said cylinder into said discharge conduit; first valve means cooperating with said supply means and discharge conduit, said first valve means having a suction position closing said discharge conduit and opening said supply means, so that material may be sucked from the latter into said cylinder, and a discharge position closing said supply means and opening said discharge conduit, so that material can be discharged from said cylinder to said discharge conduit; first double-acting piston and cylinder means cooperating with said first valve means for moving the latter between said suction and discharge positions thereof; a pump piston movable in said pump along a suction stroke for sucking material from said supply means into said cylinder when said first valve means is in said suction position thereof and along a pressure stroke for discharging material from said cylinder into said discharge conduit when said valve means is in said discharge position thereof; second double-acting piston and cylinder means operatively connected with said pump piston for reciprocating the same along said strokes thereof; a pair of hydraulic conduits communicating with each of said double-acting piston and cylinder means; second valve means communicating with said hydraulic conduits and repeatedly performing an operating cycle in which said second valve means is movable in a predetermined sequence through four positions successively directing to said hydraulic conduits fluid under pressure for actuating said first and second double-acting piston and cylinder means to produce in sequence four operations, as follows: first move said first valve means to said suction position thereof, second move said pump piston along its suction stroke, third move said first valve means to its discharge position, and fourth move said pump piston along its pressure stroke; hydraulic pump means communicating through said second valve means with said hydraulic conduits for pumping fiuid under pressure thereto according to the sequence determined by movement of said second valve means through said positions thereof, said hydraulic pump means increasing the fluid pressure in each of said conduits after the operation associated therewith has been completed so that after each operation there is an increase in the pressure of the fluid in the conduit which receives the fluid under pressure; and means cooperating with said conduits and said second valve means and responding to the increase in pressure in each conduit for automatically actuating said second valve means to move the latter automatically from one position to the next.

4. Apparatus as recited in claim 3 and wherein said means which responds to the increase in pressure in each conduit includes a cylinder communicating with said hydraulic pump means upstream of said second valve means so that said latter cylinder receives the fluid under pressure, a piston slidable in the latter cylinder and moving therein when the pressure increases, and motion transmitting means transmitting a motion of the latter piston to said second valve means for moving the latter from one position to the next.

5. Apparatus as recited in claim 3 and wherein said means which responds to the increase in pressure in each conduit includes a cylinder communicating with said hydraulic pump means upstream of said second valve means so that said latter cylinder receives the fluid under pressure, a piston slid-able in the latter cylinder and moving therein when the pressure increases, and motion transmitting means transmitting a motion of the latter piston to said second valve means for moving the latter from one position to the next, and hydraulic control means cooperating with said cylinder of said pressureresponsive means for connecting said latter cylinder automatically with a low-pressure discharge after said second valve means has moved from one position to the next so that the piston of said pressure-responsive means returns to its initial position.

6. Apparatus as recited in claim 3 and wherein said means which responds to the increase in pressure in each 11 conduit includes a cylinder communicating with said hydraulic pump means upstream of said second valve means so that said latter cylinder receives the fluid under pressure, a plston slidable in the latter cylinder and moving therein when the pressure increases, and motion transmitting means transmitting a motion of the latter piston to said second valve means for moving the latter from one position to the next, and hydraulic control means cooperating with said cylinder of said pressure-responsive means for connecting said latter cylinder automatically with a low-pressure discharge after said second valve means has moved from one position to the next so that the piston of said pressure-responsive means returns to its initial position, means cooperating with said second valve means for operating the latter manually, and manually operable means cooperating with said hydraulic control means for placing the latter in an operative or inoperative position, so that when said manually operable means places said hydraulic control means in said inoperative position said second valve means may be manually operated.

7. Apparatus as recited in claim 3 and wherein said means which responds to the increase in pressure in each conduit includes a cylinder communicating with said hydraulic pump means upstream of said second valve means so that said latter cylinder receive the fluid under pressure, a piston slidable in the latter cylinder and moving therein when the pressure increases, and motion tarnsmitting means transmitting a motion of the latter piston to said second valve means for moving the latter from one position to the next, and hydraulic control means cooperating with said cylinder of said pressureresponsive means for connecting said latter cylinder automatically with a low-pressure discharge after said second valve means has moved from one position to the next so that the piston of said pressure-responsive means returns to its initial position, means cooperating with said second valve means for operating the latter manually, and manually operable means cooperating with said hydraulic control means for placing the latter in an operative or inoperative position, so that when said manually operable means places said hydraulic control means in said inoperative position said second valve means may be manually operated, said second double-acting piston and cylindcr means including a hydraulic stop means which cooperates with the piston of said second double-acting piston and cylinder means to limit the movement thereof, and said manually operable means having a third position placing said hydraulic stop means in communication with a low pressure conduit so as to eliminate the action of said hydraulic stop means, the piston of said second double-acting piston and cylinder means being then movable through a longer stroke and the pump cylinder having an open end through which the pump piston is movable during the movement of said piston of said second double-acting piston and cylinder means through said longer stroke thereof so that access may be had to said pump piston and said pump cylinder when said manually operable means is placed in said third position thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,393,096 Fitzgerald Jan. 15, 1946 2,517,243 Rose Aug. 1, 1950 2,549,851 Pope Apr. 24, 1951 2,797,645 Kastner July 2, 1957 2,942,552 Wayt June 28, 1960