NL2024158B1 - Waterjet cutting system - Google Patents

Abstract

A waterjet cutting system (1) comprising a source of water (2), a cylinder piston pump (3), and a water delivery tube (4) with a jet nozzle (5) which can be directed to an ob- ject which is to be cut, wherein the piston (6) of the cylin- 5 der piston pump (3) is connected to a spring (7), and that the pump (3) is embodied as a one-stroke pump, wherein the piston (6) has a first position wherein the spring (7) is loaded and a second position wherein the spring (7) is relaxed, and that relaxing the spring (7) when the spring (7) is loaded drives 10 the piston (6) from the first position to the second position.

Description

Waterjet cutting system The invention relates to a waterjet cutting system comprising a source of a fluid substantially comprising water, a cylinder piston pump, and a water delivery tube with a jet nozzle which can be directed to an object which is to be cut or drilled. Whenever in this application water is mentioned, it is not intended to refer to pure water, but to water which is suitable for medical applications and which accordingly usually comprises a saline solution. The term pump as used herein should be understood as a device that is equipped to receive a fluid substantially comprising water, and which is equipped to subsequently expel such fluid substantially com- prising water. It will be obvious for the skilled person that neither the source of fluid nor the pump or any other part of the system is defined by the level of intentional or uninten- tional impurities that are present in the fluid comprised in it or flowing through it. Clearly a tube is a tube, and it will not change from being a tube depending on the substance that flows through it.

US 6,216,573 discloses such a waterjet cutting sys- tem. The challenge in using such a waterjet cutting system for cutting or drilling human tissue, in particular bone material, is to provide a high-pressure waterjet which is available with a large volume flow. It is a problem to provide a waterjet cutting system having such properties in combination. Another problem with existing waterjet cutting systems for medical ap- plications is that they are bulky and noisy.

It is an object of the invention to provide a water- jet cutting system occupying only little space, wherein the system is relatively silent in operation, and that provide a waterjet with a large volume flow and at a high-pressure.

According to the invention a waterjet cutting system is proposed having the features of one or more of the appended claims.

The waterjet cutting system of the invention differ- entiates from the prior art in that the piston of the cylinder piston pump is connected to a spring, and that the pump is em- bodied as a one-stroke pump, wherein the piston has a first position wherein the spring is or can be loaded and a second position wherein the spring is at least in part relaxed, and that relaxing the spring when the spring is loaded drives the piston from the first position to the second position there- with expelling water through the delivery tube and out of the jet nozzle. The feature of the spring-loaded piston secures that water can be expelled from the jet nozzle in a large vol- ume rate and at a high-pressure, whereas the operation of the system produces only a limited amount of noise.

After the pump has executed its stroke wherein the piston is driven from the first position to the second posi- tion, it is possible to move the piston back from the second position to the first position. If however in the second posi- tion the water is not completely expelled from the cylinder piston pump, it is possible to load the spring again and relax it for expelling the remainder of the water from the cylinder piston pump.

It is preferable that drive means are provided to move the piston from the second position wherein the spring is relaxed to the first position wherein the spring is loaded. After that the waterjet cutting system is ready for a normal further operational stroke of the piston.

Suitably the drive means comprises an electric motor that is connected to the piston. The word comprises means that the electric motor may not be the only device that is connect- ed to the piston, since preferably a transmission will be ap- plied between the electric motor and the piston.

In another embodiment the drive means comprises an hydraulic pump for supply of water into the cylinder piston pump so as to move the piston to the first position wherein the spring is loaded.

In still another embodiment the drive means comprises an hydraulic pump for directly loading the spring. Preferably the spring is mounted in a frame, wherein on opposite sides of the spring the cylinder piston pump and the hydraulic pump are provided. This restricts the total height of the system. If height is not important than it is possible that the spring is mounted in a frame, wherein the cylinder piston pump and the hydraulic pump are provided stacked upon each other. It is possible to use any type of spring in the waterjet cutting system of the invention. Preferably however the spring is embodied as a disc spring, which is advantageous because of its limited dimensions and low weight. A further advantage is that the cylinder piston pump and/or the hydrau- lic pump can be positioned in the central aperture of the disc spring, which reduces the overall height of the system.

The invention will hereinafter be further elucidated with reference to the drawing of some exemplary embodiments of a waterjet cutting system according to the invention that is not limiting as to the appended claims.

In the drawing: -figures 1A/1B schematically show a first embodiment of the waterjet cutting system according to the invention; -figures 2A/2B schematically show a second embodiment of the waterjet cutting system according to the invention; -figures 3A/B/C show a third embodiment of the water- jet cutting system according to the invention; and -figures 4A/B/C show a fourth embodiment of the waterjet cutting system according to the invention. Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

As shown in the respective figures the waterjet cut- ting system 1 according to the invention comprises a source of water 2, a cylinder piston pump 3, and a water delivery tube 4 with a jet nozzle 5 which can be directed to an object which is to be cut or drilled. As already mentioned whenever in this application water is mentioned, it is not intended to refer to pure water, but to water which is suitable for medical appli- cations and which accordingly comprises a saline solution.

The piston 6 of the cylinder piston pump 3 is con- nected to a spring 7. The cylinder piston pump 3 is further embodied as a one-stroke pump, wherein the piston 6 has a first position wherein the spring 7 is loaded (fig. 1A and fig. 2A) or can be loaded (fig. 3A and fig. 4A). The process of moving the piston 6 to a starting or first position at the beginning of a stroke is shown for different embodiments in figures 1A, 2A, 3A/3B and 4A/4B. In the embodiments of figure 1A and figure 2A moving the piston 6 to the starting or first position is completed in figure 1B and figure 2B, respectively and loads the spring 7. In the embodiments of figure 3A and figure 4A moving the piston 6 to the starting or first posi- tion makes the system ready for loading the spring 7.

During the process of moving the piston 6 to the starting or first position, fluid enters into the cylinder piston pump 3 coming from the source of water 2. The process is completed in the situations depicted in figures 1B, 2B, 3B, and 4B. After that, i.e. when the piston 6 is in its first po- sition the spring 7 is loaded as shown in figure 1B and figure 2B or the spring 7 can be loaded as is shown in figure 3B and figure 4B. In the embodiments of figure 3B and figure 4B a separate hydraulic pump 12 is applied for the pressurization of the spring 7. In the embodiment of figure 3B the hydraulic pump 12 is at a side of the spring 7 which is opposite to where the cylinder piston pump 3 is provided. In the embodi- ment of figure 4B the hydraulic pump 12 and the cylinder pis- ton pump 3 are stacked upon each other at the same side of the spring 7.

After the pressurization of the spring 7 has been completed, a user 8 can initiate that the piston 6 will move to a second position wherein the spring 7 will be relaxed.

This action of relaxing the spring 7 departing from the situa- tion wherein the spring 7 is loaded drives the piston 6 from the first position to the second position. Accordingly water that is in advance of this operation collected in the piston cylinder pump 3 will be expelled at high pressure and in a large volume rate through the water delivery tube 4 towards and out of the water nozzle 5. This is symbolized with the ar- rows 9 in figures 1B, 2B, 3C, and 4C.

The different embodiments that are shown in the re- spective figures can thus be summarized to show the following features.

Figures 1A/1B and figures 2A/2B show that drive means 10 are provided to move the piston 6 from the second position wherein the spring 7 is (at least in part) relaxed back to the first position wherein the spring 7 is loaded. Figures 1A/1B show that the drive means 10 comprises an electric motor 11 provided with an intermediate transmission, which is connected to the piston 6. Figures 2A/2B show an alternative wherein the drive means 10 comprises an hydraulic pump 12 for supply of 5 water into the cylinder piston pump 3 so as to move the piston 6 from the second position back to the first position wherein the spring 7 is loaded.

The third embodiment of figures 3A/3B/3C has the fea- ture that the drive means 10 connects to an hydraulic pump 12, however at this time the hydraulic pump 12 serves for directly loading the spring 7. Figures 3A/3B/3C further depict that the spring 7 is embodied as a disc spring 13, and that the disc spring 13 is mounted in a frame 14, wherein on opposite sides of the disc spring 13 the cylinder piston pump 3 and the hy- draulic pump 12 are provided.

A fourth embodiment is shown in figures 4A/4B/4C which show that drive means 10 are provided to move the piston 6 from the second position wherein the spring 7 (again embod- ied as a disc spring 13) is (at least in part) relaxed, back to the first position wherein the spring 7 is loaded.

Figures 4A/4B show that the drive means 10 connects for that purpose to an hydraulic pump 12 which is placed in a stacked relation with the cylinder piston pump 3. During its operation the hydraulic pump 12 moves the cylinder piston pump 3 with the piston 6 from the second posi- tion wherein the spring 7 is relaxed back to the first posi- tion wherein the spring 7 is loaded.

Figure 4C depicts finally that a user 8 can initiate that the spring 7 will be relaxed to move the piston 6 to the second position, during which pro- cess water will be expelled through the water delivery tube 4 and the nozzle 5 at high pressure and in a large volume rate.

This is symbolized with the arrows 9 in figure AC.

Although the invention has been discussed in the foregoing with reference to exemplary embodiments of the waterjet cutting system of the invention, the invention is not restricted to these particular embodiments which can be varied in many ways without departing from the invention.

The dis- cussed exemplary embodiments shall therefore not be used to construe the appended claims strictly in accordance therewith.

On the contrary the embodiments are merely intended to explain the wording of the appended claims without intent to limit the claims to these exemplary embodiments. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using these exem- plary embodiments.

Aspects of the invention are itemized in the follow- ing section.

1. A waterjet cutting system (1) comprising a source of a fluid substantially comprising water (2), a cylinder pis- ton pump (3), and a water delivery tube (4) with a jet nozzle (5) which can be directed to an object which is to be cut, characterized in that the piston (6) of the cylin- der piston pump (3) is connected to a spring (7), and that the pump (3) is embodied as a one-stroke pump, wherein the piston (6) has a first position wherein the spring (7) can be loaded and a second position wherein the spring (7) is at least in part relaxed, and that relaxing the spring (7) when the spring (7) is loaded drives the piston (6) from the first position to the second position therewith expel- ling water through the delivery tube (4) and out of the jet nozzle (5).

2. Waterjet cutting system according to claim 1, character- ized in that drive means (10) are provided to move the piston (6) from the second position wherein the spring (7) is relaxed to the first position wherein the spring (7) is loaded.

3. Waterjet cutting system according to claim 2, character- ized in that the drive means (10) comprises an electric motor (11), and preferably a transmission, that is con- nected to the piston (6).

4. Waterjet cutting system according to claim 2, character- ized in that the drive means (10) comprises an hydraulic pump (12) for supply of water into the cylinder piston pump (3) so as to move the piston (6) to the first posi- tion wherein the spring (7) is or can be loaded.

5. Waterjet cutting system according to claim 2, character- ized in that the drive means (10) comprises an hydraulic pump {12} for directly loading the spring (7).

6. Waterjet cutting system according to any one of claims 1 - 6, characterized in that the spring (7) is mounted in a frame (14), wherein on opposite sides of the disc spring (13) the cylinder piston pump (3) and the hydraulic pump (12) are provided.

7. Waterjet cutting system according to any one of claims 1 - 6, characterized in that the spring (7) is mounted in a frame (14), wherein the cylinder piston pump (3) and the hydraulic pump (12) are provided stacked upon each other.

8. Waterjet cutting system according to any one of claims 1 - 7, characterized in that the spring (7) is embodied as a disc spring (13).

Claims (8)

CONCLUSIONS A water jet cutting system (1) comprising a fluid source substantially containing water (2), a cylinder piston pump (3) and a water delivery tube (4) with a nozzle (5) orientable towards an object to be cut, characterized in, that the piston (6) of the cylinder piston pump (3) is connected to a spring (7) and that the pump (3) is designed as a one-stroke pump, the piston (6) having a first position in which the spring (7) can be tensioned and a second position in which the spring (7) is at least partially relaxed, and releasing the spring (7) when the spring (7) is tensioned, the piston (6) of the first position floats to the second position, causing water to be ejected through the dispensing tube (4) and out of the jJet nozzle (5). Waterjet cutting system according to claim 1, characterized in that a drive means (10) is provided to move the piston (6) from the second position in which the spring (7) is relaxed to the first position in which the spring (7) is stretched. Waterjet cutting system according to claim 2, characterized in that the drive means (10) comprises an electric motor {11), and preferably a transmission, which is connected to the piston (6). A water jet cutting system according to claim 2, characterized in that the drive means (10) comprises a hydraulic pump (12) for supplying water to the cylinder piston pump (3) to move the piston (6) to the first position. position in which the spring (7) is or can be tensioned. Waterjet cutting system according to claim 2, characterized in that the drive means (10) comprises a hydraulic pump (12) for direct tensioning of the spring (7). Water jet cutting system according to one of claims 1 to 6, characterized in that the spring (7) is mounted in a frame (14), wherein on opposite sides of the disc spring (13) the cylinder piston pump (3) and the hydraulic pump (12) are provided. Water jet cutting system according to one of claims 1 to 6, characterized in that the spring (7) in a frame (14) mounted, with the cylinder piston pump (3) and the hydraulic pump (12) stacked on top of each other. A water jet cutting system according to any one of claims 1 to 7, characterized in that the spring (7) is designed as a disk spring (13).