DE10122346A1 - Hydraulic pump unit for lifter for raising load has pump cylinder for pumping hydraulic pressure medium to outlet to which lifting cylinder is connectable - Google Patents

Abstract

The hydraulic pump unit (10) for a lifter (9) for raising a load has a pump cylinder (11) for pumping a hydraulic pressure medium (14) to an outlet (15) to which a lifting cylinder is connectable. It has a valve arrangement, with which the pressure medium at the outlet for the lifting cylinder is limited to a predetermined highest value. The hydraulic pump unit has at least one second pump cylinder (12) connected in parallel to the first pump cylinder. A coupling device (13) is provided, with which the first and the at least one second pump cylinder are operable in a coupled state.

Description

The invention relates to a hydraulic pump unit for a Lifter for lifting a load, with a pump cylinder for Pumping a hydraulic pressure medium to an outlet to which a lifting cylinder can be connected, and with a valve arrangement with the one in line at the outlet for the lifting cylinder the pressure provided by the print medium on a vorbe agreed maximum value can be limited. The invention relates also a lifter with such a hydraulic pump unit is equipped.

For lifting loads, especially heavy loads, are known lifters with such a hydraulic pump unit. By pumping the pump Cylinder of the hydraulic pump unit becomes a pressure medium, for example hydraulic oil, pressurized. That under Pressurized pressure medium flows into a lifting cylinder which is intended for lifting the load. The pump actuation of the pump cylinder is usually done manually. This is difficult with heavy loads and can be particularly difficult heavy loads result in the necessary actuation forces  to actuate the pump cylinder from one Operator can no longer be applied to the load can no longer be raised.

It is therefore an object of the present invention to provide a ver relatively easy to operate hydraulic pump unit or one equipped with one, correspondingly light to create actuatable jack.

To solve the problem is in the aforementioned Hydrau Lik pump unit provided that it has at least a second Pump cylinder that pa to the first pump cylinder is connected in parallel, and that a coupling device is provided with which the first and the at least one second pump cylinder can be actuated coupled.

By connecting several pump cylinders in parallel, the Area enlarged, the pressure forces on the print medium practices. This area is defined by the piston surface of the piston the pump cylinder defines. The operator of the invention The hydraulic pump unit only needs to be reduced accordingly Apply lower actuation forces so that the pump unit is easier to operate. This means that lifting is also behavior Heavy loads are possible without difficulty.

In addition, the pressure unit of the pump unit becomes a lifting cylinder smaller amount of pressure medium pumped through the parallel switch multiple pump cylinders enlarged so that this a comparatively fast stroke movement during an actuation stroke  the pump unit experiences. Especially under confined spaces spatial conditions, for example if for a bet lever for manual actuation of the pump unit only short actuation distance is available, this is advantageous way.

Advantageous embodiments of the invention can be found in the depend claims as well as in the description.

In principle, the pump cylinders can actuate the same length of time have adjustment strokes. However, it has proven to be beneficial found that the pump cylinders have different lengths Have actuation strokes.

The coupling device expediently has one swivel arm on, with the actuators for actuation supply of the pump cylinder, in particular its piston rods, each because they are pivotally connected. In a preferred out leadership form of the invention are the actuators in Arm longitudinal direction one behind the other transversely to the pivot axis of the pivoted arms arranged. As a result, au actuation strokes of different lengths achieved. Wei furthermore, the pump cylinders can be timed Work offset.

For the swivel connection between at least one actuator cleaning element and the pivotable arm is advantageously a Spring provided.  

In a further expedient embodiment of the invention passes through at least one of the actuating elements on the arm for swivel connection at a reach-out take, so that the respective actuator in the Pass-through recess is pivotable. Here is the arm arranged between entrainment projections on the respective gene actuator are provided. Such a solution is easy to manufacture.

In principle, a single pressure relief valve arrangement could be provided for the total of the pump cylinders for the pressure of the pressure medium provided by the lifting cylinder limits a predetermined maximum. It is always advantageous however, it provided that each pump cylinder have a single valve arrangement of the valve arrangement is assigned with which on the output side of the respective individual valve arrangement pressure of the pressure provided for the lifting cylinder mediums can be limited to the predetermined maximum value. A separate pressure relief valve arrangement for each individual valve order can be optimal for the pump Be adjusted cylinder.

Furthermore, it is expediently provided that during intake stroke through the individual valve arrangements a backflow of Pressure medium from the outlet into the respective pumping chamber of the ih NEN assigned pump cylinder can be prevented.

The individual valve arrangements expediently provide a Preflow of the hydraulic pressure medium during the pressure stroke of them  each assigned pump cylinder from their respective Pump chamber preventable to a pressure medium inlet.

One can be used for each of the two aforementioned measures Check valve assembly with one or more check valves may be provided. In any case, you get a single valve arrangements that are designed as compact units can.

A pressure relief valve arrangement, as above, can also be inserted into this explained, integrated, which by the each of them orderly pump cylinder generated pressure medium pressure on egg limited a predetermined maximum. Anyway forms one such a single valve assembly is a unit that in Ver is easily interchangeable.

In a further embodiment of the invention, the one can represent independent invention, it is provided that the hydraulic pump unit has a base section on which the first and / or the at least one second pump cylinder by means of pressure-tight connections, for example screw connections ties, are arranged and that the base section is one too the first and / or the at least one second pump Cylinder leading pressure medium supply channel and / or a between the first and / or the at least one second Pump cylinder and the outlet channel arranged on has. Due to the pressure-tight connections, leakage, especially a loss of pressure medium between the outlet a respective pump cylinder and the outlet of the hydraulic pump unit,  avoided. The pump cylinders are preferred wise detachable, especially by screwing in, with the base partie connected, what from a manufacturing perspective is partaking.

In the case of the aforementioned measure, it is advisable to pre-scan hen that at least one single valve arrangement between the Base section and the pump cylinder assigned to it and is held by it. When removing the resp The single valve arrangement, which, as explained above, can be a compact unit, easily accessible, so that in the event of a fault, it can be functioning single valve arrangement can be replaced can.

The hydraulic pump unit advantageously has a drain Direction for releasing the pressure medium from the lifting cylinder on. By means of the drain device, the respective col pressure chamber introduced into the lifting chamber be drained from this, so that the lifting cylinder to its starting position, which it actuates before operating the pump Cylinder held, can return.

In principle, the hydraulic pump unit according to the invention could by a motor drive, for example one Electric drive to be operated. However, it is advantageous before seen that they have a manual actuator has. This can be done, for example, by a piston rod  the pump cylinder or a lever attached to it be formed.

It is also advantageously possible that the manual operation is formed by the coupling device.

The hydraulic pump unit is expediently in one Pressure medium reservoir of the lifter arranged. The feed of the pressure medium to the pump cylinders is therefore very high subject.

In the following, the invention is illustrated by means of an embodiment game explained with reference to the drawing.

The single figure shows a hydraulic pump unit 10 arranged on a jack 9 , with pump cylinders 11 , 12 , which can be actuated in a coupled manner by a coupling device 13 .

With the pump unit 10 , a pressure medium 14 , for example hydraulic oil, can be pumped to an outlet 15 , which is connected to a piston chamber 16 of a lifting cylinder 17 . By flowing into the piston chamber 16 pressure medium 14 , a piston 18 is displaced, for example upwards, wherein a piston rod 19 arranged on the piston 18 can be used as a force handle to lift a load, not shown. The lifting cylinder 17 is only indicated schematically in the figure, wherein a housing 20 of the lifting cylinder 17 is only partially drawn. In principle, other lifting cylinders supplied by the pump unit 10 with pressure medium 14 , not shown, are also possible.

The pump cylinders 11 , 12 are arranged on a base section 21 , which is made of metal, for example, and which in the exemplary embodiment comprises an outlet section 22 with an outlet channel 24 leading to the outlet 15 and an inlet section 25 with an inlet channel 26 through the pressure medium 14 can flow to the pump cylinders 11 , 12 . The inlet section 25 is arranged at the top of the outlet section 22 and is firmly connected to the latter, for example by screw, adhesive or welded connections. The base part 21 could in principle also be made in one piece.

At the top of the inlet section 25 housings 27 , 28 of the pump cylinders 11 , 12 are arranged by means of pressure-tight connections. In the present case, the housings 27 , 28 are screwed into receptacles 29 , 30 arranged on the inlet section 25 in the form of recesses. In principle, they could also be glued or welded into the base part 21 or formed by the latter. In the housings 27 , 28 each piston receiving spaces 31 and 32 are arranged, in which each piston 33 and 34 are arranged movable back and forth. The pistons 33 , 34 are made of plastic material in the exemplary embodiment. They sit on piston rods 35 , 36 , to which they are unbuttoned, for example. The piston rods 35 , 36 protrude upwards from the housings 27 , 28 and form actuating elements for actuating the pump cylinders 11 , 12 .

In the receptacles 29 , 30 underneath the pump cylinders 11 , 12 , individual valve arrangements 37 and 38 configured as compact valve units are arranged, which are held by the housings 27 and 28 in the receptacles 29 and 30 , respectively. Seals 42 are provided at the bottom in the receptacles 29 , 30 for sealing the individual valve arrangements 37 , 38 against the outlet section 22 . Above the individual valve arrangements 37 and 38 are between these and the pistons 33 , 34 Druckme medium 14 receiving pump chambers 75 and 76th A seal 43 is arranged on the upper side of the pump chambers 75 and 76 , respectively.

The individual valve arrangements 37 , 38 are connected to the inlet channel 26 on the inlet side. During the suction stroke, the pump cylinder 11 , 12 can flow from this pressure medium 14 into the pumping chambers 75 , 76 through check valves 39 of the individual valve arrangements 37 , 38 . During the pressure stroke of the pump cylinders 11 , 12 , their pistons 33 , 34 displace the pressure medium from the pump chambers 75 , 76 , this being pumped via pressure relief valves 41 and check valves 40 of the individual valve arrangements 37 , 38 into the outlet channel 24 . During the pressure stroke, the check valves 39 prevent the pressure medium 14 from the pump chambers 75 , 76 from flowing back into the inlet channel 26 . The check valves 40 prevent pressure medium 14 located in the outlet channel 24 from flowing into the pump chambers 75 , 76 . The piston 18 could otherwise lower undesirably under load.

The schematically illustrated pressure relief valves 41 , which are exemplary for any pressure relief valve arrangements, limit the pressure provided by the pump cylinders 11 , 12 and provided at the outlet 15 for the lifting cylinder 17 to a predetermined maximum value, which depends, for example, on the nature of the respective lifting cylinder 17 and / or depend on the maximum load that can be lifted by the jack 9 . When the maximum pressure value is reached, the overpressure valves 41 return pressure medium 14 displaced from the pump chambers 75 , 76 into the inlet channel 26 .

On the intake stroke in the pumping chambers 75, 76 inflowing pressure medium 14 by flowing during the pressure stroke the exhaust port 24 pressure medium 14 is indicated by arrows 44, indicated by arrows 45th As long as the lifting cylinder 17 is still moved unloaded by a load to be lifted, relatively large pressure medium 14 flows into the piston chamber 16 during the pressure strokes of the pump cylinders 11 , 12 , which results in a rapid movement of the piston 18 in the lifting direction. If the Hebezy cylinder 17 is then loaded, for example because a support rod arranged on the piston rod 19 , not shown, attaches non-positively to a load, not shown, the actuating forces required to actuate the pump cylinders 11 , 12 are kept low by doing so the displacement surface of the piston 33 and the displacement surface of the piston 34 for displacement of pressure medium by 14 from the pumping chambers 75 , 76 is used.

To discharge pressure medium 14 from the piston chamber 16 of the lifting cylinder 17 , a discharge device 46 is provided which is connected to the outlet channel 24 and, in the present case, is arranged in a row with the pump cylinders 11 , 12 and which has the outlet channel 24 in its closed position with a Closure piece 47 , on which a seal 48 is arranged, closes. The drain device 46 is operable by a vorlie ing rod-like actuating element 49 , the egg 50 arranged on the inlet section 25 engages through and is screwed into this. By turning the actuating element 49 , the drain device 46 can be adjusted between a closed position closing the outlet channel 24 and an open position opening it to the surroundings. In the open position, pressure medium 14 can flow out of the outlet channel 24 (indicated by dashed arrows), so that the piston 18 of the lifting cylinder 17 can move toward th.

In the exemplary embodiment, the pump unit 10 is arranged in a closed housing 51 , which forms a reservoir for the pressure medium 14 (an exemplary fill level is shown in dashed lines). A breakthrough 52, which correlates with the outlet 15 and leads to the lifting cylinder 17, is provided on the housing 51 . The base portion 21 is disposed at the bottom of the housing 51 and connected by screws 53, which also can nen for connecting the inlet section 25 to the outlet portion 22 to the housing 51st On its upper side, the housing 51 is closed by, for example, a screwed-on, at least preferably removable, cover 54 , which can be opened for maintenance purposes, for example for refilling pressure medium 14 . The cover 54 is penetrated by the discharge device actuating element 49 as well as by the piston rod 36 at openings 58 , at which seals 57 are arranged, which retain the pressure medium 14 in the interior 98 of the housing 51 . For this purpose, seals 55 are also arranged in the contact area of the cover 54 on the housing 51 .

On the lifter 9 is outside (outside the housing 51 ) actuation device 59 rotatably arranged, which has an arranged on egg nem arm 60 arm 61 , at the free end of a handle 62 , for example a handle, is arranged. By means of the actuator 59 , the piston rod 36 can be moved up and down. For this purpose, this is pivotally connected to the arm 61 . The piston rod 36 extends through the arm 61 at a penetration recess 63 . Above and below this entrainment projections 56 are arranged on the piston rod 36 , between which the arm 61 is held.

During an actuation stroke (pressure stroke or suction stroke) of the actuation device 36 , not only the piston rod 36 is moved up or down, but also the piston rod 35 via the coupling device 13 . The coupling device 13 is arranged by means of a swivel joint 65 on the pump unit 10 , in the exemplary embodiment on an upwardly projecting projection 66 of the inlet section 25 , which extends essentially parallel to the piston rods 35 , 36 .

The coupling device 13 has an arm 64 which can be pivoted by means of the swivel joint 65 between a lower position, shown in the figure with continuous lines, which is assumed after a pressure stroke, and an upper position, shown in dash-dotted lines, which can be pivoted according to a Intake stroke is taken. The actuating element 49 , as well as the piston rods 35 , 36 pass through the arm 64 at penetration recesses 67 , 68 , 69 which run obliquely in the arm 64 , so that, in order to obtain a pivoting play when it is in its lower position, they obliquely to the actuating element 49 or the piston rods 35 , 36 run and in its upper position essentially parallel to these. In any case, the penetration recesses 67 , 68 , 69 have a course such that a swivel joint is created between the piston rods 35 , 36 serving as actuating elements and the coupling device 13 . The penetration recess 69 can be open towards the free end of the arm 64 and can therefore grip around the piston rod 36 in a fork-like manner.

The coupling device 13 and the arm 64 are arranged in the area of the penetration recesses 68 , 69 between the lower and upper ren, on the piston rods 35 , 36 arranged driving projections 70 , 71 and 72 , 73 , respectively, for the transmission of force between the Coupling device 13 and the piston rods 35 , 36 serve in a pressure or a suction stroke. In the piston rod 35 , a helical spring 74 is arranged between the driving projections 70 , 71 , which fulfills the function of a swivel joint. The spring 74 transmits tensile forces to the piston rod 35 during the suction stroke. During the pressure stroke, however, the coupling device 13 acts directly on the projection 70 , which enables relatively large transmission forces.

The piston rod 35 facing away from the joint 65 protrudes from the housing 51 serving as a pressure medium reservoir. The joint 65 facing the piston rod 36 terminates within the Ge häuses 51st

The coupling device 13 is arranged within the housing 51 serving as a pressure medium storage container.

It goes without saying that any combinations of the measures specified in the description and in the claims are possible. Furthermore, further refinements of the invention are readily possible:
The pistons 33 , 34 could have different active surfaces, in particular different diameters.

The coupling device 13 could also be arranged outside of the inner space 98 . With such a configuration, it would also be readily possible for the coupling device, which is now on the outside, to simultaneously form an actuating device for the pump unit. For this purpose, one could, for example, attach a handle or another handle to the coupling device.

Rollers or wheels not shown may be arranged for moving the lifter 9 to the lifter. 9

Instead of the separate pressure relief valves 41 assigned to each pump cylinder 11 , 12 , a pressure relief valve arrangement assigned to both pump cylinders 11 , 12 could also be provided in the pump unit 10 .

The actuators of the pump cylinder could with the Coupling device by rotating joints containing rotary shafts be connected, preferably several parallel to each other lele axes of rotation are provided.

The drain device actuator 49 could be located away from the coupling device 13 .

Claims (15)

1. Hydraulic pump unit for a jack ( 9 ) for lifting a load, with a pump cylinder ( 11 ) for pumping a hydraulic pressure medium ( 14 ) to an outlet ( 15 ) to which a lifting cylinder can be connected, and with a Valve arrangement with which a pressure of the pressure medium ( 14 ) present at the outlet ( 15 ) and provided for the lifting cylinder can be limited to a predetermined maximum value, characterized in that the hydraulic pump unit ( 10 ) has at least one second pump cylinder ( 12 ). has, which is connected in parallel to the first pump cylinder ( 11 ), and that a Kopplungsvorrich device ( 13 ) is provided with which the first and the at least one second pump cylinder ( 11 , 12 ) can be actuated coupled. 2. Hydraulic pump unit according to claim 1, characterized in that the pump cylinders ( 11 , 12 ) have actuation strokes of different lengths. 3. Hydraulic pump unit according to claim 1 or 2, characterized in that the coupling device ( 13 ) has a pivotable arm ( 64 ) with the actuating elements ( 35 , 36 ) for actuating the first and the at least one second pump cylinder ( 11 , 12 ), in particular the piston rods ( 35 , 36 ), are each pivotally connected. 4. Hydraulic pump unit according to claim 3, characterized in that a spring ( 74 ) is provided in at least one swivel connection. 5. Hydraulic pump unit according to claim 3 or 4, characterized in that the arm ( 64 ) has at least one penetration recess ( 68 , 69 ) penetrated by an actuating element ( 35 , 36 ) with pivot play, and in that the arm ( 64 ) between driving projections ( 70 , 71 ; 72 , 73 ) is angeord net, which are provided on the actuating element ( 35 , 36 ) on both sides of the penetration recess ( 68 , 69 ). 6. Hydraulic pump unit according to one of the preceding claims, characterized in that each pump cylinder ( 11 , 12 ) is assigned a single valve arrangement ( 37 , 38 ) of the valve arrangement ( 37 , 38 ) with which the output side on the respective Single valve arrangement ( 37 , 38 ) of the pressure of the pressure medium ( 14 ) that is available for the lifting cylinder can be limited to the predetermined maximum value. 7. Hydraulic pump unit according to claim 6, characterized in that during the suction stroke by the individual Ventilanordnun gene ( 37 , 38 ) a backflow of the pressure medium ( 14 ) from the outlet ( 15 ) in the respective pumping chamber ( 31 , 32 ) of each of them assigned first or at least one second pump cylinder ( 11 , 12 ) can be prevented. 8. Hydraulic pump unit according to claim 6 or 7, characterized in that through the individual valve arrangements ( 37 , 38 ) a pre-flow of the hydraulic pressure medium ( 14 ) during the pressure stroke of the respectively assigned first or at least one second pump cylinder ( 11 , 12 ) from their respective pump chamber ( 31 , 32 ) to a pressure medium inlet. 9. Hydraulic pump unit according to one of the preceding claims, characterized in that it has a base section ( 21 ) on which the first and / or the at least one second pump cylinder ( 11 , 12 ) is arranged by means of pressure-tight connections and that the base section ( 21 ) has a pressure medium supply channel ( 26 ) leading to the first and / or the at least one second pump cylinder ( 11 , 12 ) and / or between the first and / or the at least one second pump cylinder ( 11 , 12 ) and the outlet ( 15 ) arranged from the outlet channel ( 24 ). 10. Hydraulic pump unit according to claim 9, characterized in that at least one individual valve arrangement ( 37 , 38 ) is arranged between the base part ( 21 ) and the pump cylinder ( 11 , 12 ) assigned to it and is held by it. 11. Hydraulic pump unit according to one of the preceding claims, characterized in that it has a discharge device ( 46 ) for releasing the pressure medium ( 14 ) from the lifting cylinder. 12. Hydraulic pump unit according to one of the preceding claims, characterized in that it has an actuating device ( 59 ) for manual actuation. 13. Hydraulic pump unit according to claim 12, characterized in that the manual actuating device ( 59 ) is formed by the coupling device ( 13 ). 14. Lifter with at least one lifting cylinder for lifting a load and with a hydraulic pump unit ( 10 ) for its supply with a pressure medium ( 14 ) according to one of the preceding claims. 15. Lifter according to claim 14, characterized in that it has a storage container ( 51 ) for receiving the pressure medium ( 14 ), in which the hydraulic pump unit ( 10 ) is arranged.