HYDRAULIC PUMP MOUNTED ON A CARRIER

Abstract: The invention relates to a hydraulic pump to be driven by means of human muscle power for driving a hydraulic hand tool, wherein the hand tool is connectable to the pump by means of a flexible hydraulic conduit, wherein the pump is mounted on a substantially flat carrier. The pump is preferably formed by a pump which can be manually operated by means of a control lever and the control lever is connectable to the pump at least at two mutually differing angles.

Description: HYDRAULIC PUMP MOUNTED ON A CARRIER The present invention relates to a hydraulic Wttp to be driven by means of human muscle power for driving a hydraulic hand tool, wherein the hand tool is connectable to the pump by means of a flexible hydraulic conduit. Such hydraulic pumps are generally known, for in¬ stance from the catalogues of Holmatro B.V. of Raamsdonk- veer, the Netherlands. Such pumps are usually used in emergency situations, wherein work must be done by the users of the pump under considerable mental stress. Envisaged here are situations such as earthquakes and the like wherein no flat ground is usually available on which to place a pump. It is however desirable, par¬ ticularly in the case of manually operated pumps, that these be placed on a flat ground, since the forces for driving must be generated by exerting a force on a lever relative to the pump. It is therefore important that the pump be held at a fixed position. This is often difficult in the case of prior art pumps which have a small surface area. The object of the invention is to avoid the above stated problem. This object is achieved in that the pump is mounted on a substantially flat carrier. By placing the pump on a flat carrier a sufficiently great stability of the pump is obtained so that, also when relatively large forces are applied to the pump, the pump can retain its originally occupied position. According to a preferred embodiment the pump is formed by a pump which can be manually operated by means of a control lever and the control lever is connectable to the pump at least at two mutually differing angles. This offers the option for the user of the pump of connecting the lever to the pump at that angle at which it pumps most easily; this will also depend on the angle at which the pump and the carrier are placed on the available ground. According to yet another embodiment the carrier comprises a metal frame on which a metal plate is fixed and the pump is mounted on the frame. According to a preferred embodiment the carrier is adapted to fix the hydraulic hand tool by means of a rapid-action lock. This offers the advantage of an easily handled unit which can be stored as such in storage areas or in rescue vehicles and carried by preferably two people to the location where the device has to be used. A complete unit is then available on the spot with which the necessary operations can be carried out. Further auxiliary material is then no longer required. It is pointed out here that two persons are required for an effective use of the device according to the invention,- one person to operate the pump and a second person to handle the tool, for instance a spreading or cutting tool . According to yet another preferred embodiment the pump is a three-stage pump, wherein the three pump cylin¬ ders are arranged concentrically on the same piston rod. This results in a compact, effective construction. Other attractive embodiments can be found in the remaining sub-claims. The invention will now be elucidated with reference to the annexed drawings, in which: figure l shows a perspective view of an assembly of a pump according to the invention together with a hand tool connected thereto,- figure 2 shows a partly broken away perspective detail view of the pump depicted in figure l; and figure 3 shows a hydraulic diagram of the pump according to the invention. Shown in figure 1 is an assembly 1 formed by a frame 10 to which is fixed a base plate 2. Further fixed to frame 10 is a pump 3 which is formed by a pump housing 4 on which is mounted an oil reservoir 5. Pump housing 4 is connected to frame 10 by means of a screw connection, while use is made for mounting of oil reservoir 5 of a bracket 6 fixedly connected to the oil reservoir Further mounted on the pump housing is a lever mechanism 7 on the top part of which is arranged a lever holder 8 into which s inserted a lever 9. Lever holder 8 comprises a shaft around which lever 9 is rotatable relative to the holder. Lever 9 is fixable in holder 8 by means of a collar which is arranged on lever 9 and movable m axial direction along the lever and which fits into two recesses arranged for this purpose m the lever holder. The lever position can herewith be adapted to the height and position of the user The base plate 2 is formed essentially by a profiled plate on the underside of which is arranged a carrier frame 10 For handling purposes the plate is provided with two handles 11. Further arranged on base plate 2 are two spring-mounted brackets 12 onto which is clamped a hydraulic hand tool designated as a whole by 13. The hydraulic hand tool will not be discussed further here since it is already per se widely known. The hydraulic hand tool 13 is further provided with a handle 14 which also fulfils a function m the fixing of hand tool 13 onto base plate 2. In the present embodiment the hydraulic hand tool 13 is connected by means of a pair of flexible high-pressure hoses 16,17 to the oil reservoir 5. One of the high- pressure hoses 16 herein functions as pressure line and the other high-pressure hose 17 as return line. In the shown embodiment the high-pressure hoses 16,17 are both always connected to hand tool 13 as well as to pump housing 4; it is equally possible however to use releas¬ able couplings and to connect the hydraulic high-pressure hoses by means of couplings to the hydraulic hand tool 13 or to pump housing 4. In the shown embodiment the hydraulic high-pressure hoses 16,17 are confined by the handle 14, this is par¬ ticularly important when they have a considerable length and would hang loose without optional confining meanε . It is not per se essential, however,- if the hoses are suffi¬ ciently short this provision will be unnecessary. It will be apparent that due to the shown steps the use of the device is greatly simplified; the device can easily be carried by two people from a rescue vehicle to the location of use, wherein the dimensioning of various parts is such that the device can easily be transported by two people wherein they each grip one of the handles 11. The hydraulic hand tool 13 can subsequently be picked up by releasing the spring-mounted brackets 12. One of the two people can then release the lever 9 from the fixation bracket 18 arranged for that purpose and the person concerned can begin pumping. During pumping the second person can perform his operations with the hydrau¬ lic hand tool 13. Mention is made in the case of the embodiment shown here of a spreading/cutting device as hydraulic hand tool; it will be apparent that other types of hydraulic hand tool can also be used such as lifting devices and the like. Figure 2 shows in more detail the construction of the pump housing and the pump cylinder. Recessed into the pump housing 4 is a staged cylindrical cavity 19 in which is arranged a piston 20 likewise in staged form. Piston 20 of course fits precisely into cylindrical cavity 19 and in order to obtain a good sealing relative to the cylinder wall the piston is provided with sealing rings and the like. Such devices form part of the prior art so that no further discussion thereof is required. The piston is connected by means of two piston rods 21 to lever mecha¬ nism 7 so that movements of lever 9 are transmitted to lever holder 8 which is fixedly connected to lever mecha- nism 7 and these movements are transmitted to the piston by means of piston rod 21. Use is further made herein of a crank pin 22 and a piston pin 23. The hollow space of oil reservoir 5 is connected by means of a channel 24 to each of the separate spaces behind the relevant pistons. In the three separate channels 25,26 respectively 27 arranged for this purpose are placed non-return valves. Arranged on the other side in pump housing 4 is a channel 28 which is connected by means of the relevant channels 29,30,31 to the spaces at the staged piston 23. A high pressure is thus generated in channel 28 through the action of piston 23, wherein the three-stage operation of the pump is of particular importance. Channel 28 extends over the whole length of pump cylinder 5 and is connected to the pressure line of the pair of flexible hoses 16,17. The return line is connected to the space inside the oil reservoir 5. More particularly when the pump rod 9 is moved upward the three-stage piston 20 will be carried along and an underpressure will be created in the three piston chambers, whereby the oil from the tank will flow into the piston chambers. The oil herein passes through non¬ return valves 25,26,27. When pump rod 9 is moved down- ward, the non-return valves 25,26,27 close automatically and the oil will be pressed past non-return valves 29,30, 31. When pump rod 9 is moved upward once again the non¬ return valves 29,30,31 will close automatically so that the oil cannot flow back under the pistons . The oil is then drawn in again via non-return valves 25,26,27. Should the pressure behind the non-return valves 29,30,31 reach a pressure above 50-60 bar the relief valve F will then come into operation. The oil pressure in the low-pressure piston chamber is then discharged to the tank. No further force will hereby be required to press the oil out of the low-pressure piston chamber. The effective oil flow rate is therefore decreased by the flow rate of the low-pressure stage. Should the pressure behind the non-return valves 29,30,31 reach a pressure above 250-260 bar the relief valve E will then come into operation. The oil pressure in the medium-pressure piston chamber is then discharged to the tank. No further force will hereby be required to press the oil out of the medium-pressure piston chamber. The effective oil flow rate is therefore decreased by the flow rate of the low-pressure and medium-pressure stage. Should the pressure in front of the non-return valves 29,30,31 reach a pressure above 680-690 bar the relief valve D will come into operation. The oil pressure in the high-pressure piston chamber is then discharged to the tank. Pressure relief C is present as secondary safety device. This will discharge the oil pressure to the tank when it rises above 750-800 bar. The total pressure in the system can be discharged to the tank by opening the relief valve G. The oil pressure is guided to a hydraulic 4/3 valve to control the tool 13. Behind the 4/3 valve the oil flow passes through a pressure-actuated non-return valve which prevents the oil pressure in the hydraulic tool falling away involuntarily. The hydraulic tool 13 is moreover provided on both sides of the hydraulic cylinder with a pressure relief valve Al and A2 which at a pressure above 800-850 bar discharges the pressure to the return line. Further arranged in the return line is a pressure relief valve B which discharges the pressure of the return line to the outside when it rises above 350-400 bar. It will be apparent that other pressure values can be used instead of the above mentioned values. Reference is otherwise made to figure 3 which shows the hydraulic diagram of the pump. It will be apparent that it is possible to vary from the shown embodiments in diverse ways without departing from the invention.

Claims: CLAIMS 1. Hydraulic pump to be driven by means of human muscle power for driving a hydraulic hand tool, wherein the hand tool is connectable to the pump by means of a flexible hydraulic conduit, characterized in that the pump is mounted on a substantially flat carrier. 2. Hydraulic pump as claimed in claim 1, characterized in that the pump is formed by a pump which can be manually operated by means of a control lever and that the control lever is connectable to the pump at least at two mutually differing angles . 3. Hydraulic pump as claimed in claim 1 or 2, char¬ acterized in that the carrier comprises a metal frame on which a metal plate is fixed and that the pump is mounted on the frame. 4. Hydraulic pump as claimed in any of the foregoing claims, characterized in that the carrier is adapted to fix the hydraulic hand tool by means of a rapid-action lock. 5. Hydraulic pump as claimed in any of the foregoing claims, characterized in that the carrier is provided on its underside with at least three sharp elements protrud¬ ing a small distance below the bottom surface of the carrier for fixing of the carrier parallel to itself. 6. Hydraulic pump as claimed in any of the foregoing claims, characterized in that the frame is provided with handles. 7. Hydraulic pump as claimed in any of the foregoing claims, characterized in that the pump is a three-stage pump, wherein the three pump pistons are arranged concen- trically on the same piston rod. 8. Hydraulic pump as claimed in claim 7, characterized in that the pump is provided with an automatic control unit which controls the pressure adjustment of the pump stages such that the connected tool makes use of the available power in optimal manner. 9. Hydraulic pump as claimed in claim 8, characterized in that the automatic pressure control unit is adapted to render the pump stages ineffective wherein the maximum pressure is smaller than the momentary operating pressure. 10. Hydraulic pump as claimed in claim 7, 8 or 9, characterized in that the pump is provided with a collec¬ tive oil reservoir and that the suction mechanism of the pump is adapted to be able to operate at angles of a maximum of 40° to the horizontal.

Inventors: BLAAS RONALD PETER, SCHUETZ CHRISTIAAN ARNOLD, BLAAS, RONALD, PETER, SCHUETZ, CHRISTIAAN, ARNOLD
Applicants: BLAAS RONALD PETER, HOLMATRO B V, SCHUETZ CHRISTIAAN ARNOLD, BLAAS, RONALD, PETER, HOLMATRO B.V., SCHUETZ, CHRISTIAAN, ARNOLD
Application year: 1997
Main classification: A62B3
IPC codes: A62B3, F04B5