WO1996001166A1

WO1996001166A1 - Pipe-cutting apparatus

Info

Publication number: WO1996001166A1
Application number: PCT/NL1995/000226
Authority: WO
Inventors: Johannes Arnoldes Van Deyzen
Original assignee: Jama Beheer Heinenoord B.V.
Priority date: 1994-07-06
Filing date: 1995-06-27
Publication date: 1996-01-18
Also published as: NL9401129A

Abstract

The invention relates to a pipe-cutting apparatus, comprising: a support for the pipe of which a part must be cut; a rotatable round blade which is movable into a position in which the blade extends into the line of the pipe; and drive means for driving in rotation the blade or the pipe, wherein means are arranged for urging the blade in the direction toward the pipe. It will be apparent that a pipe-cutter as known from the prior art is not suitable for cutting through pipes at high speed, particularly not when these are made of stainless steel. Due to the fact that the apparatus provides means for urging the blade in the direction toward the pipe, there results the possibility of having these means exert a force such that the pipe is cut through in a short time and a minimum number of rotations.

Description

PIPE-CUTTING APPARATUS

The invention relates to a pipe-cutting apparatus, comprising: a support for the pipe of which a part must be cut; a rotatable round blade which is movable into a position in which the blade extends into the line of the pipe,* and drive means for driving in rotation the blade or the pipe.

Such an apparatus is generally known, in the form for example of so-called pipe-cutters which are used by gas fitters and plumbers for shortening gas pipes and water pipes.

These known apparatus comprise a bracket provided with rollers, wherein the rollers are fixed to the bracket such that the bracket can be rotated round the pipe for cutting and wherein to the bracket is fixed a rotatable blade which is movable for instance by means of a spindle. After making a rotation with this known apparatus, wherein a cut is made when rotation takes place, in order to make the cut deeper the blade must be moved more towards the centre of the pipe by means of the spindle, whereafter the cut can be deepened. These actions are repeated until the pipe has been completely severed.

As stated, these known apparatus are generally intended for cutting through generally thick-walled steel or copper pipes. It is of course also known to saw through pipes.

Sawing through pipes results in the problem that both the sawn-off piece of pipe and the remaining part of the pipe must be deburred, which forms an extra operation.

Furthermore, a saw-cut is also quite rough so that a further operation is necessary to remove the roughness of the sawn-off piece of pipe and the remaining piece of pipe.

These problems arise with all types of material, not only with steel or copper pipes, but likewise with for example stainless steel pipes. With stainless steel pipes the further problem arises that sawing is very time-consuming. It can be stated for example that it requires about 15 seconds to saw through a thin-walled stainless steel pipe, so that if a large number of saw-cuts have to be made the time required is considerable.

A further drawback lies in the fact the saw for use with stainless steel is subject to a high degree of wear, so that the tool life thereof is short. The object of the present invention is to provide such an apparatus, wherein the above-stated problems are avoided.

This object is achieved by providing an apparatus as stated in the preamble with means for urging the blade in the direction toward the pipe.

It will be apparent that a pipe-cutter as known from the prior art is not suitable for cutting through pipes at high speed, particularly not when these are made of stainless steel. Due to the fact that the apparatus provides means for urging the blade in the direction of the pipe, there results the possibility of having these means exert a force such that the pipe is cut through in a short time and a minimum number of rotations.

It will be apparent that this apparatus makes it possible to cut through the pipes of various materials at a high speed without the occurrence of burrs or rough surfaces. It will also be apparent that the above stated method can be performed at a high speed.

The present invention will be elucidated hereinafter with reference to the annexed drawings, in which: figure 1 shows a perspective view of an apparatus according to the invention; figure 2 shows a side view of the apparatus depicted in figure 1; figure 3 shows a sectional view according to the arrow III in figure 1; figure 4 shows a sectional view according to the arrow IV in figure 3; figure 5 is a partly broken away view of the carriage associated with the apparatus shown in figure 1 as according to the arrow V; figure 6 is a sectional view according to arrow VI in figure 5,* figure 7 shows a sectional view of the supports of the supporting device forming part of the apparatus depicted in figure 1 as according to the arrow VII; figure 8 shows a sectional view according to the arrow VIII in figure 7; figure 9 is a schematic perspective view of the cutting apparatus according to the invention as according to a first alternative embodiment; and figure 10 is a schematic perspective view of a second alternative embodiment of a cutting apparatus according to the invention.

The apparatus 1 shown in figure 1 comprises a frame 2, on which a bed 3 is fixed, and on the side of which is arranged a cutting device in the narrow sense 4. The apparatus further comprises a carriage 5 movable along the bed and an actuating rod device 6. The apparatus is finally provided with an electronic control unit 7. The bed 3 is provided with a guide rod 8 which is connected to the bed by means of feet 9. A gear rack 10 is fixed to the underside of the bed. As is likewise shown in figure 2, the carriage 5 is provided with a gear wheel 11 which engages with the toothed rack 10. The gear wheel can be driven by means of a servomotor 12. Use is made of a flexible cable duct 13 resting on a support 14 to supply electrical signals and electrical energy to the carriage. In order to support the pipe 15 for shortening use is made of supports 16 which extend through openings arranged in the bed 3.

The operation of the cutting apparatus will first be elucidated with reference to figure 3. Figure 3 shows that the cutting device in the narrow sense is provided with two side pieces 17,18 which together form a frame and which are each connected to the frame 2 of the total machine. Movable in vertical direction between the two side pieces 17,18 is a block 19 in which is mounted a shaft 20 on which is fixed the round blade 21.

Above block 19 is arranged a pressure block 22 which can exert a downward directed force against block 19. Recessed for this purpose in pressure block 22 is a cavity 23 is which is closed at the top by a stud bolt 24. Screwed onto the stud bolt is a gear rim 25 which is provided with an internal screw thread which is in engagement with the stud bolt and which is provided on its periphery with a conical gear wheel 26 which is in engagement with a pinion 27 fixed to a shaft 28 mounted in side piece 17. The shaft 28 is rotatable by means of two handles 29,30.

In order to enclose the gear rim 25 a threaded bush 31 is placed on the conical gear rim 25, which bush is closed on its top side by an axial bearing 32, the other side of which rests against a plate 33 extending between side pieces 17,18. On the underside of gear rim 25 is arranged a bearing 34 which rests on its underside against a plate 35 which is likewise arranged between side pieces 17,18. It is thus possible by way of causing the handles 29,30 to rotate to turn the stud bolt 24 downward. The stud bolt is provided with a sleeve 36 which is arranged sealingly in a cover plate of the pressure block 22. The cavity 23 in the pressure block is connected by means of a feed channel 37 to a source of hydraulic pressure with which hydraulic liquid can be supplied to the space 23 and placed under pressure. On its top side the space 23 is closed by a gasket 38 above which an annular space 39 is present. This annular space 39 is likewise connected to a feed channel 40 for hydraulic liquid. On the underside of the blade is arranged a yoke 41 which can be guided in vertical direction along two cylindrical guides 42,43. Both guides 42,43 are otherwise connected by a plate 44 into which is screwed a stud bolt 45 which impinges on the yoke 41. By turning the stud bolt 45 by means of a device not shown in the drawing, the height of yoke 41 can be adjusted. Yoke 41 carries two support rollers 46,47 for the pipe 15 to be cut.

The cutting apparatus is further shown in figure 4. The block 19 is provided with two radial bearings

48,49, in which the cutting shaft 20 is mounted. The blade 21 is fixed to cutting shaft 20. The shaft 20 is driven by means of a keyed connection 50 by the output shaft 51 of a driving hydraulic motor 52. Arranged for the purpose of lubricating blade 21 is a tray 53 in which lubricating liquid 54 is present. The level of the lubricating liquid 54 is such that the rotatable blade is partially immersed in the lubricant 5 . It is possible to move blade 21 upward by means of the pressure block 22 such that it cuts through the pipe 15 during one rotation of the pipe 15. However, it is conceivable that in the case of other materials or other thicknesses of material it may be necessary to perform a greater number of rotations of the pipe. In order to drive the pipe use is made of the pipe drive device which is arranged in the carriage 5 and which will be elucidated with reference to figure 5.

The carriage 5 shown in figure 5 is formed by a block, not shown in the drawing, which is connected to a support block 55. In the support block is arranged a bush 56 inside which a rotatable, internal bush 57 is situated. Two bearings 58,59 are arranged between bushes 56 and 57, while a support bearing bush 60 is arranged to further support the internal bush 57. The internal bush 57 is thus rotatable relative to bush 56 and block 55. In order to drive internal bush 57 the latter is connected to a belt pulley 61 around which is trained a belt 62. The belt 62 is drivable by means of a hydraulic motor 63 placed on the carriage.

The internal bush 57 is connected on one side to an attachment 64 provided with a recess 65. The recess 65 is adapted for gripping the pipes 15 for shortening.

Furcher arranged round the attachment is a sleeve 66 which is otherwise connected to bush 56 by means of a bearing 67. To shift the pipe 15 for shortening use can of course be made of the possibility of displacing carriage 5. According to another embodiment it is however also possible, when displacement through a small turn has to take place, to make use of the displacing device integrated into the carriage and formed by two inward extending rings of the bush 56, which rings are designated 68 and 69 respectively. Between the rings is a space 70 inside which extends an external ring 69 fixed to the support bearing 68. The space 70 is connected by means of two channels 105, 106 respectively to supply means for hydraulic liquid, with which ring 69 can thus be moved relative to block 55. The ring 69 is fixedly connected to the support bearing bush 60 and exerts pressure on sleeve 66 via bearing 67. The attachment piece and therewith the pipe 15 are thus also moved.

A supporting body 72 and an inner blade 73 are arranged at the position of the blade 21 in the interior of the pipe. The right-hand supporting body 73 is held in place by means of a pipe 74 extending through the pipe 15 for shortening. The inner blade 73 extends precisely up to the flat side of the outer blade 21. Following on directly therefrom the supporting body 73 is provided with an annular notch 75. The supporting body 72 is provided on both sides with chamferings 76. Between the two bodies 72,73 are arranged four segments 77a, 77b,77c and 77d which are provided on their inner side with a conical cavity. Arranged in the conical cavity is a conical body 78 which is connected to a pull rod 79 extending through the pipe 74. The pull rod is provided at its end with a screw thread 80 on which a nut 81 is screwed, wherein a pressure spring 82 is arranged between body 72 and nut 81. By means of pulling on pull rod 79 the conical body 78 is moved to the right, whereby segments 77 a-d are urged outward to enlarge the diameter of the supporting body formed by segments 77 a-d. The function hereof is to straighten deformations of the pipe caused by the cutting.

Finally, the action of the apparatus will be elucidated with reference to the more schematic figures 9 and 10.

Figure 9 shows schematically how the blade 21 is mounted and can be driven by means of the hydraulic motor 52. Shown schematically is the function of the pressure block 22 with which the shaft 20 and therewith the blade 21 can be moved downward. The pressure rollers 46,47 are represented by the yoke 41. For supporting the cutting process use is made of a round supporting element 83 which extends beyond the end of the pipe. At the position where it is free, the supporting element is carried by a bearing 84 received in a fixedly disposed bearing block 85. In this embodiment the pipe is pushed manually over the supporting element. The pipe for shortening is herein fed from the front side, in the drawing the left-hand side, of the machine, pushed over the supporting element 16 to the correct position, whereafter a part 86 of the pipe 15 is shortened by means of the rotating blade. The blade 21 is then moved back again to its original position and the pipe 15 shifted manually, whereafter in similar manner a subsequent cut is made and the following piece of pipe shortened.

Finally, figure 10 shows an embodiment wherein it is not the blade which is driven but wherein the pipe for shortening is driven. This second alternative embodiment again comprises a supporting element 86 which is drivable by means of a gear rim 87 fixed thereon. The supporting element 86 is otherwise rotatably mounted by means of bearings 88,89 in a bearing block 90. By means of the gear rim 87 provided with conical teeth a hydraulic motor 91 on the output shaft, to which a conical gear rim 92 is also fixed, drives the supporting element 86 in rotation. In order to transport the pipes 15 for shortening use is made of a clamping device 93 which is movable along a rail 94 in axial direction of the pipe for shortening. The clamping device comprises two jaws 95,96 which are connected by means of brackets 97,98 respectively to a carriage 99 which is movable along rail 94. A linear drive member 100 is arranged for opening and closing the jaws

95,96. For driving the pipe 15 pushed onto the supporting element 86 the end of supporting element 86 is provided with three segments 101a,101b and 101c which are provided on their inner side with a conical cavity. In this conical cavity extends a conical body 102 which is connected to an actuating rod 103 extending through the supporting element. The actuating rod is movable by means of a linear drive means 104. In this embodiment the blade 21 is mounted for free rotation. It will be apparent that this apparatus operates as follows. From the left-hand side in the drawing the pipe piece 15 is pushed onto supporting element 16 until the correct position under the saw cut is obtained. The linear drive element 104 is then energized, whereby the segments 10la-c are urged apart, and the pipe 15 is fixedly connected for rotation to supporting element 86. The motor 91 is then switched on, the pipe 15 is thus driven in rotation, whereafter the blade 21 is moved into the cutting position and the cut made. As soon as the cut piece of pipe has been removed, the linear drive means 104 is energized in reverse direction, whereby pipe 15 is released from the supporting member. Thereafter the pipe is fixedly clamped on the outside by means of the clamping device 93 which is moved in axial direction until the correct position is obtained, whereafter the cutting process commences again and the following piece of pipe is cut. It will be apparent that various elements of the various embodiments can be mutually combined.

It is further possible to diverge from the drawn and discussed embodiment without going beyond the scope of the invention.

Claims

1. Pipe-cutting apparatus, comprising:

- a support for the pipe of which a part must be cut,

- a rotatable round blade which is movable into a position in which the blade extends into the line of the pipe,* and drive means for driving in rotation the blade or the pipe, characterized by means for urging the blade in the direction toward the pipe.

2. Apparatus as claimed in claim 1, characterized by support means for internally supporting the pipe at least in the vicinity of the location where the blade cuts the pipe.

3. Apparatus as claimed in claim 2, characterized in that the support means are adapted to internally support the pipe only in the vicinity of the cutting position.

4. Apparatus as claimed in claim 1, 2 or 3, characterized in that the drive means are adapted to drive the blade.

5. Apparatus as claimed in claim 3, characterized in that the support means have a diameter at the position of the blade which is considerably smaller than the internal diameter of the pipe.

6. Apparatus as claimed in claim 5, characterized in that the diameter of the support means at the position of the blade can be temporarily enlarged to substantially the internal diameter of the pipe.

7. Apparatus as claimed in claim 6, characterized in that the support means are formed at the position of the blade by a number of segments with a circular periphery and an element for urging the segments outward in radial direction.

8. Apparatus as claimed in claim 7, characterized in that the element for urging the pipe outward is formed by a conical body connected to a rod extending in the interior of the pipe.

9. Apparatus as claimed in any of the foregoing claims, characterized by feed means for feeding the pipe for cutting to the cutting position.

10. Apparatus as claimed in claim 9, characterized in that the feed means comprise a clamp, which is adapted to grip the pipe, and a drive member for driving the clamp in axial direction of the pipe.

11. Apparatus as claimed in claim 9, characterized in that the feed means are adapted to drive the pipe in rotation.

12. Apparatus as claimed in claim 11, characterized in that the feed means are arranged on a carriage movable in axial direction of the pipe, and that the feed means comprise a rotatably drivable hollow spindle provided with gripping claws.