EP1390179B1

EP1390179B1 - Device and method for cutting

Info

Publication number: EP1390179B1
Application number: EP02766714A
Authority: EP
Inventors: Olle Petersson
Original assignee: SP-Verktyg I Halmstad AB
Current assignee: SP-Verktyg I Halmstad AB
Priority date: 2001-04-30
Filing date: 2002-04-26
Publication date: 2008-04-09
Anticipated expiration: 2022-04-26
Also published as: DK1390179T3; SE0101515D0; WO2002087836A1; DE60226020T2; EP1390179A1; DE60226020D1; SE0101515L; ATE391589T1; SE518959C2; ES2304449T3

Abstract

A cutting device (1) and a method for cutting hoses (2), preferably reinforced hydraulic hoses, which device comprises a cutting means (3) to cut the hose (2) at a cutting point (4). The cutting device comprises at least one source of pressure (8) for pressurising a medium inside the hose (2) to a pressure amounting to between 1 to 100 bars, and connecting means (9) for pressurising said medium inside the hose (2), said connecting means (9) adapted to be applied at the hose (2) ends.

Description

The present invention relates to a cutting device for cutting hoses, preferably reinforced hydraulic hoses. The invention likewise relates to a hose cutting method.

Technical Background of the Invention

In the process of cutting hoses, particularly in conjunction with cutting hydraulic hoses, amounts of fragments of metal and particles of rubber are formed inside the hoses adjacent to the point of cutting. If no measures are taken to prevent the particles from spreading during the cutting operation, such fragments and particles may be found as far from the point of cutting as 20-30 cm into the hose parts. The metal fragments, which originate from the cut-off metal reinforcement material, are heated to very high temperatures during the cutting operation, with the result that they may penetrate into and "melt-adhere" to the inner face of the hose, causing laceration damages. When the hydraulic hose is later put into use, these particles may come loose and cause damage to pumps and valves and clogging of filters. Residual products and dusts emanating from the cutting operation consequently cause serious problems that in a later stage contribute to considerable losses and costs with respect to comparatively sophisticated equipment.
In order to clean a cut-off hose part of particles thus released during the cutting operation, methods such as through-blowing by means of air or high-pressure flushing with liquid are used. These are time-consuming and expensive methods which also fail to ensure that the cut-off hose part will be satisfactorily cleaned. In addition, test results show that scratches and other abrasion damages are caused to the inside of hoses cleaned by machine.
Another prior-art method of hose cleaning is to propel a plug of foam rubber through the hose cavity. It has been found that the foam-rubber plug has a tendency to spread the dust and the residual particles on the faces of the hose itself without removing them as desired.
Patent Specification SE502864 discloses a method of cutting hoses by means of insertion into the hose of a plug of a special design to a position, where the cutting is intended to be carried out. The plug is then severed essentially at its centre into two parts in conjunction with the hose being cut at the desired place. The suggested hose-cutting method with the aid of a plug designed for that purpose has the advantage of protecting the inner jacket face of the hose from particles and chips. In practice, however, a number of problems remain to be solved to obtain rational handling in conjunction with the cutting operation. The patent specification discloses one way of forcing the plug to the desired position inside an unrestrained hose by means of a rod-like tool. In order to allow the position of the plug to be determined thereafter, the rod-like tool is pulled out of the hose. The position of the inserted plug coincides with the length of the rod part that has been introduced into the hose and that rod part is now placed alongside the external face of the hose, to thus allow the position of the plug from the hose end to be determined. Because the hoses are opaque, there is no possibility, however, of verifying by ocular means that the plug actually still occupies the intended position, when the hose, in the following sequence, is moved up to the cutting means to be severed.
The frictional resistance encountered as the plug is being inserted into the hose causes further problems of placing the plug in the correct position. In addition, the possibility of cutting long hoses is restricted by the length of the rod-like tool itself. As clearly apparent from the above, a more rational handling method would be highly desirable with respect to hose cutting operations of the kind outlined above, and above all it would be desirable to be able to cut hoses in a manner that ensures a higher quality of cut hoses as regards absence of dust, metal chips, residual particles and so on.

Summary of the Invention

The fundamental idea of the invention is to solve the problems outlined above and to make possible rapid and efficient cutting of hoses, particularly hoses intended for hydraulically operated machinery, and this in a manner that prevents various residual products from adhering to internal hose faces at the hose ends at the point of cutting.
A further object of the invention is to suggest a method and a device enabling cleaner cutting of hoses, irrespectively of the intended length of the hose to be cut.
In accordance with the teachings of the invention these objects are obtained by means of the hose-cutting device defined in the appended claim 1 and the hose cutting method defined in the appended claim 9. Preferred embodiments of the device are defined in the dependent claims 2-8.
Thus, the invention concerns a cutting device for cutting hoses, which device comprises a cutting means to cut the hose at a cutting point, at least one source of pressure for pressurising a medium inside the hose to a pressure amounting to between 1 and 100 bars, and connecting means for pressurising said medium inside the hose, said connecting means adapted to be applied at the hose ends to continuously supply pressure to the medium inside the hose at least for as long as the cutting of the hose is in progress.
The inventive cutting device allows cleaner cutting of hoses to be made without particles and dust penetrating into and adhering to the inner face of the hose, thanks to it being possible to perform the cutting operation while the hose to be cut is simultaneously subjected to an excess pressure. Owing to the excess air pressure thus applied, dust and particles that form during the cutting operation will instead flow in the direction outwards, out of the hose ends. The flow generated by the excess pressure applied inside the hose makes it possible to simultaneously cool the cutting means. This is a particularly preferred feature when the cutting means is in the shape of a blade. Preferably, the medium inside the hose is air.
According to one variety of the inventive cutting device, the temperature of the air may be regulated to cool the cutting means as desired. This feature is advantageous in that it considerably prolongs the serviceable life of the cutting means without the cutting device having to be equipped with additional devices to create a cooling effect on the cutting means, contrary to what is necessary in the case of a several of prior-art cutting machines.
In order to facilitate handling during the cutting operation, the cutting device preferably is equipped with a feeder designed to advance the hose up to a cutting point. In order to facilitate the cutting process further, the inventive cutting device is provided with measuring equipment, along which the hose may be displaced to allow the intended length of the hose to be determined in a simple manner before the cutting operation is initiated.
Because the cutting is performed on a hose that is already pressurised, the hose-cutting operation produces considerably smaller and fewer dust particles and residual products from the cutting operation in the hose opening compared with prior-art technology. In order to improve the cutting results, the pressurisation of the medium inside the hose should be carried out continuously throughout the entire cutting cycle.
The cutting device in accordance with the invention preferably comprises two sources of pressure, each one of which is formed with a connecting means, the latter in turn designed to be coupled to a hose end in order to allow supply of pressure to the medium inside the hose.
The invention thus also concerns a hose-cutting method, comprising the steps of pressurising a medium inside the hose to a pressure of 1-100 bars by application onto the hose ends of connecting means, which are coupled to at least one source of pressure, and of effecting the cutting by means of the cutting device while the medium is pressurised. Preferably, the medium is pressurised continuously for at least as long as the hose-cutting operation is in progress. The method steps are repeated for each length of hose to be cut, thus forming a cutting cycle. In order to obtain a rational cutting cycle the hose-feeding step etcetera may be made automatic.
Preferably, air is used as the hose-pressurising medium. In accordance with one alternative method the medium inside the hose is temperature-controlled. In this manner the inventive method offers a possibility of cooling the cutting means at the same time as the latter cuts through the hose. The method and the cutting device in accordance with the invention are suitable for use in conjunction with cutting of reinforced hoses, such as reinforced hydraulic hoses.
In accordance with another preferred embodiment of the invention, the cutting device is formed with a measuring unit. With the aid of this measuring unit, the hose end may be displaced with a high degree of accuracy to a position spaced the required distance from the cutting point, in which position the hose may be fixed. This distance coincides with the desired length of the hose to be cut off.

Brief Description of the Drawings

The method of the present invention as well as examples of embodiments of a device for performing the method will be described in the following in more detail with reference to the accompanying drawing. In the drawing:

Fig 1 is a schematic perspective view of the cutting device.
Fig 2 is a schematic perspective view of an alternative embodiment of the cutting device.

Detailed Description of Preferred Embodiments

One preferred embodiment of the invention will be described in the following with reference to the accompanying drawings.
Fig 1 shows a cutting device 1 in accordance with a preferred embodiment. The cutting device 1 comprises a first body 13 and a second body 14 carrying between them a rail 15, which interconnects the two device bodies 13, 14.
The first body 13 has an essentially flat working top 18 extending in a horizontal plane at a suitable working level and onto which top a hose 2 is intended to be advanced preliminary to its being cut. Said first body also comprises a cutting means 3, in the shown example in the form of a motor-driven cutting disc 16. The cutting disc 16 is mounted on the motor for rotational movement.
In addition, a holder-on member 17 are arranged to be shifted essentially in one plane towards the cutting disc 16 between two extreme positions, one inactive position and one cutting position, not shown in closer detail in the drawing figures. According to one preferred embodiment the cutting means 3 comprises an abutment member 17 abutting against the hose 2 when the cutting disc 16 penetrates the hose at the intended cutting point. The abutment member 17 preferably is located spaced from the position of rest of the cutting disc 16, the space in between intended to accommodate hoses of varying dimensions that is being advanced on the working top.
In addition, the first body 13 comprises a feeder unit 6, which advances the hose 2 across the working top 18 in a controlled manner. The hose 2 is advanced by the feeder 6 in a direction of advancement A, past the cutting point 4 and further on towards the rail 15.
A stop means 5 is arranged for displacement on the insertion rod 7. The stop means 5 thus is moveable and in accordance with a preferred embodiment it may also be fixed in any desired position along the rail 15. In accordance with a preferred embodiment a measuring unit 12 is provided on the rail, which measuring unit serves to determine the distance between the cutting point 4 and the end of the hose, the latter preferably being placed in abutment against the stop means 5 in conjunction with the cutting operation.
Because the length 7 of the hose 2 that is being advanced is prevented from being moved past the stop means 5, the distance from the stop means 5 to the cutting point 4 corresponds to the length that the cut-off hose portion will have after cutting. The measuring unit 12 could be designed as a conventional simple measuring ruler that extends along the path of advancement of the hose or else as a more sophisticated measuring system including transducers, readers and display means for presentation of the measurement values. One preferred kind of transducer consists of a measuring wheel, which is read digitally.
By means of a preferred embodiment of the invention thus a method is suggested of diverting residual machining fragments generated in conjunction with hose cutting operations, said method comprising the steps of pressurising a medium contained inside the hose to a pressure of between 1 and 100 bars by application onto the hose ends of connecting means 9, which are coupled to at least one source of pressure. In accordance with one preferred embodiment, the source of pressure 8 is a conventional compressor generating a pressure of about 8 bars. Once the medium inside the hose has been pressurised, the cutting means 3 is activated to cut into the hose 2, the medium still being pressurised.
Suitably, the pressure inside the hose 2 amounts to between 1 and 100 bars, the purpose being to prevent residual particles from adhering to the inner faces of the hose 2, but preferably the pressure amounts to between 1 and 20 bars, and more preferably to between 4 and 8 bars, most preferably to about 8 bars. Modern compressors of conventional technology generate about 8 bars, making these compressors particularly useful. In accordance with an alternative embodiment of the invention, the source of pressure 8 is a fan. In accordance with a third alternative embodiment of the invention, the source of pressure 8 is an air pump. One suitable type of pressure generator is a sliding vane compressor having a capacity of free output air of about 0.6 m³/min. Compressor delivering about 0.6 and 2.2 m³/min of free air are commonly available today and they may be used to construct the inventive device. In order to achieve a suitable flow of air and a suitable pressure level of the medium in the hose to be severed, it is an advantage to be able to vary the amount of freely delivered air in the inventive cutting method and device in order to enable satisfactory cutting results in consideration of the properties and the characteristics of the hose in question.
In accordance with a preferred embodiment, the hose ends are designed to have a complementary engagement fit with their respective connecting means 9, whereby an airtight connection is created at each hose end, allowing a pressure to build up inside the hose in anticipation of the cutting operation. The opposite end of the connecting means 9 is connected to its source of pressure via a hose or other suitable means. In accordance with an alternative embodiment of the invention, shown in Fig 2, the connecting means 9 may be supplied with a pressurised medium, for example by means of pressurised air, from a common source of pressure 8. This drawing figure likewise shows the manner in which a hose reel 20 is arranged to advance considerable lengths of hose 2, for example in a controlled manner. In this case, the connecting means 9 preferably is coupled to the hose end that is arranged in the centre of the hose reel 20, via a swivel joint that in this case is incorporated in the connecting means 9. It will be appreciated that for hose lengths of considerable length, it may be advantageous to arrange a hose reel also on the receiving end of the cutting device. The means connecting the source of pressure 8 to the hose 2 also in this case preferably is a swivel-joint type of connection coupled to the hose reel 20 at the centre thereof.
As the cutting means 3 is activated to cut into the hose 2, the excess pressure inside the hose generates an exiting flow, entraining residual particles in the direction out of the hose 2. Since the pressure is applied continuously and with an essentially equal force from both ends of the hose, two oppositely directed flows are created at the point of cutting, both of which are essentially of equal strength. The pressure of the flows might lessen during the cutting step as medium escapes but should not be lower than 1 bar.
In accordance with a preferred embodiment, the cutting means 1 is provided with safety means of standard type, such as emergency stop means, two-hand control devices, no-voltage circuit breakers and a spring-actuated shield for the cutting disc 16. The cutting means 3 need not necessarily have a circular shape as illustrated in the drawings but could be configured in various ways and could for example be a blade-like cutting blade, which is moved in a backwards-forwards movement to cut through the hose 2. In accordance with further alternative embodiments of the inventive cutting device not shown herein, the cutting means 3 is a water jet or a laser. As will be appreciated, the method of cutting the hose 2 may be implemented by making the cutting device 1 operate in a more or less automated way. For example, in accordance with one embodiment of the invention, the stop means 5 is designed with an automated stop function. The automated stop function is triggered off when the hose 2 abuts against the stop means 5.
As will be appreciated, some of the characteristic features defined above may be combined in various ways to form additional embodiments within the scope of protection of the invention. The method in accordance with the invention as also the device for implementing the method thus are not restricted to what has been shown and described herein. The invention thus may be modified further in several ways within the scope of the inventive idea and the appended claims.
The device is for example applicable also to rigid hoses and pipes. When rigid hoses or pipes are used, these should be regarded as included in the concept of hose as referred to herein. Further preferred embodiments of the invention thus may be created by providing the cutting device with additional equipment within the scope of what the expert in the field considers to be obvious, such as hose reels for winding-on the hose, not shown in detail as they are well known. By combining characteristic features of different alternative embodiments of the invention described herein additional possible varieties may be obtained that are within the scope of the inventive idea. It is considered to be within the competence of the expert in the field to choose a compressor, alternatively a pump or other pressure sources to provide suitable embodiments within the scope of the invention.
According to a third embodiment of the invention, one of the connecting means 9 is a seal applied to one hose end, whereupon the pressure of the medium inside the hose is built up by connecting the opposite hose end to a source of pressure 8. This embodiment is not shown in detail in the drawings. In addition, it should be understood that other media than air could be used to build up an excess pressure inside the hose before it is cut, and in this manner create a flow of medium out of the hose that prevents residual products and particles from entering the hose in conjunction with and also following the cutting operation.

Claims

A cutting device (1) for cutting hoses (2), which device comprises a cutting means (3) to cut the hose (2) at a cutting point (4),
characterised in that the cutting device comprises at least one source of pressure (8) for pressurising a medium inside the hose (2) to a pressure amounting to between 1 and 100 bars, and connecting means (9) for pressurising said medium inside the hose (2), said connecting means (9) adapted to be applied at the hose (2) ends to continuously supply pressure to the medium inside the hose (2) at least for as long as the cutting of the hose (2) is in progress.
A cutting device (1) as claimed in any of the preceding claims, wherein said medium inside the hose (2) is air.
A cutting device (1) as claimed in claim 1, said device comprising a feeder (6) arranged to advance said hose (2).
A cutting device (1) as claimed in any one of the preceding claims, said device comprising measuring equipment (12) for allow determination of suitable lengths of hose.
A cutting device (1) as claimed in any one of the preceding claims, said cutting means being a blade.
A cutting device (1) as claimed in any one of claims 1-5, wherein said cutting means is a water jet.
A cutting device (1) as claimed in any one of claims 1-5, wherein said cutting means is a laser.
A cutting device (1) as claimed in any one of the preceding claims, said device comprising two source of pressure (8), each one of which has a connecting means (9), which means in turn being designed to be coupled to a hose end in order to allow supply of pressure to the medium inside the hose (2).
A hose-cutting method,
characterised by the steps of pressurising a medium inside the hose (2) to a pressure of 1-100 bars by application onto the hose ends of connecting means (9), which are coupled to at least one source of pressure (8), and of carrying out the cutting by means of said cutting means (3), which cuts into the hose (2) while the medium inside the hose (2) is pressurised.
A method as claimed in claim 9, said medium inside the hose (2) being pressurised continuously for at least as long as the hose-cutting operation is in progress.
A method as claimed in any one of claims 9-10, wherein said medium for pressurising the hose (2) is air.
A method as claimed in any one of claims 9-11, wherein said medium inside the hose (2) is temperature-controlled.
A method as claimed in any one of claims 9-12, said method intended for cutting reinforced hoses, such as for example reinforced hydraulic hoses.