US3763559A

US3763559A - Pipe cutting apparatus

Info

Publication number: US3763559A
Application number: US00217882A
Authority: US
Inventors: E Axbjer
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-01-20
Filing date: 1972-01-14
Publication date: 1973-10-09
Anticipated expiration: 1990-10-09
Also published as: DE2202122A1; FR2122966A5; CA940696A; IT946659B; JPS5322712B1; AU455391B2; GB1344947A; AU3801072A; SE343226B

Abstract

An improvement in pipe cutting apparatus of the type having a number of cutting elements mounted for rotation on pins which also pivotally connect together the links of a roller type chain, means for tightening the chain around the pipe during a pipe cutting operation, and means for moving the chain around the pipe. The improvement resides in the fact that the chain tightening means is provided with parts which present co-acting guide surfaces adapted to align the ends of the chain length with respect to each other. Further, means are provided for adjusting the distance between the side links of each chain link and for locking the side links in the adjusted position.

Description

United States Patent [1911 Axbjer PIPE CUTTING APPARATUS [76] Inventor: Erik Lennart Axbjer, Bultvagen 22,

Hagersten, Sweden 22 Filed: Jan l4, 1972 21 Appl. No.: 217,882

[30] Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS 11/1950 Great Britain 30/100 Oct. 9, 1973 Primary ExaminerOthell M. Simpson Assistant Examiner-Mark S. Bicks Attorney-Eric H. Waters et a1.

[57] ABSTRACT An improvement in pipe cutting apparatus of the type having a number of cutting elements mounted for rotation on pins which also pivotally connect together the links of a roller type chain, means for tightening the chain around the pipe during a pipe cutting operation, and means for moving the chain around the pipe. The improvement resides in the fact that the chain tightening means is provided with parts which present co-acting guide surfaces adapted to align the ends of the chain length with respect to each other. Further, means are provided for adjusting the distance between the side links of each chain link and for locking the side links in the adjusted position.

4 Claims, 4 Drawing Figures PIPE CUTTING APPARATUS The present invention relates to an arrangement in pipe cutting apparatus of the type comprising anumber of circular cutting elements mounted on a chain of the roller type which is capable of being placed around the pipe to be cut and which has side links pivotally mounted on pins on which the circular cutting elements, flanked by the side links, are mounted for rotation for cutting engagement with the pipe, tensioning means for connecting together the ends of the length of chain utilized in effectinga cutting operation and for tightening the chain around the pipe, and means connected to the tensioning means for causing the chain to move in the peripheral direction of the pipe, said means being particularly of the type capable of imparting a reciprocating movement to the chain and including attachment means secured to the pipe and a detachable linear piston engine capable of being coupled between the attachment means and the tensioning means.

An object of the present invention is to provide a new and useful arrangement in pipe cutting apparatus of the above described type, whereby such apparatus can be used for their intended purpose with the minimum of adjustment work and whereby the cutting precision of the apparatus can be retained in a relatively simple manner. i

To these ends it is proposed in accordance with the invention that with pipe cutting apparatus of the above described type the distance between the side links of each chain link of the cutting chain be made adjustable and that means be provided for maintaining the adjusted distance between the links, and that the tensioning means components be provided with co-acting guide surfaces arranged to bring the ends'of the chain into correct alignment with each other, thereby ensuring that all cutting elements are placed on and cut trated embodiment, are provided with knurled or serrated surfaces 18 arranged to engage the outer surface of the pipe 11, and which are held in position by means of a roller chain 19, one end of the chain being'secured passes through a hole in a projection 22 on the arm 16,

along one andthe same line around the periphery of I the pipe.

' The invention will nowbe described in greater detail with reference to an embodiment thereof illustrated in the accompanying drawing, further features of the invention being disclosed in connection therewith.

in the drawing, FIG. 1 illustrates in plan view a pipe cutting appatus positioned on a pipe and including an arrangement according to the invention.

HO. 2 is a side view of the apparatus shown in FIG. 1.

FIG. 3 is a fragmentary view in larger scale, illustrating a preferred arrangement for adjusting the distance between the side links of the chain of cutting elements.

FIG. 4 illustrates, partly diagrammatically, a device for causing the piston in the linear piston engine to move backwards and forwards.

In the drawing, in which-like parts are identified with like reference numerals, the numeral 10 indicates a cutting chain placed around a pipe 11 to be cut. The reference numeral 12 indicates a tensioning means for tighting the chain around the pipe 11. The tensioning means 12 is connected with a drive means, which in the illustrated embodiment comprises an engine 14 and an engine attachment element 15, by means of a pin 13 in a manner such as to enable the drive means to be readily disconnected from the tensioning means.

The attachment 15 comprises a substantially V- shaped

block having arms

16 and 17 which, in the illuswhile screwed onto the spindle 21 on the side of the projection opposite the hook 20 is a nut 23, by means of which the chain 19 can be tightened around the pipe 11, with the projection 22 acting as an abutment surface, and therewith lock the V-block to the pipe. In the region where the arms l6, l7 meet, the V-block barries a pin 24 which extends parallel with the pipe 11 and which, for the purpose of connecting together the attachment 15 and the engine 14, is arranged to be accommodated in a complementary bore disposed in a bracket structure 25 which is securely connected to the engine 14.

The engine 14, which is in the form of a linear piston engine, preferably a pneumtatic piston-cylinder assembly, comprises a cylinder 26 housing a piston (not shown), the piston rod of which is indicated by the reference numeral 27. The piston rod 27 supports at its free end a bifurcate member 28 arranged to be detachably connected to the tensioning means 12 by means of the pin 13, which passes through a hole of complementary configuration and size in the tensioning means and in the legs of the bifurcate member 28. The engine 14 is thus arranged to be pivotally connected to the tensioning means 12 and the attachment 15 by .means of the

pins

13 and 24 respectively in a manner to enable it to be easily detached therefrom.

In the illustrated embodiment, the tensioning means 12 comprises mainly two parts in the form of

arms

30, 31 pivotally connected together at one end thereof by means of a pin 29. In accordance with the invention, the aforementioned parts of the tensioning means, in theillustrated instance the

arms

30, 31, have wide coacting' guide surfaces 32, 33, which ensure that the arms when pivoting around the pin 29 constantly move in one and the same plane extending at right angles to the pin. Specifically, as seen in FIG. 1, the arm 30 is formed with spaced lugs between which the arm 31 extends so that the co-acting guide surfaces 32,33 confront one another. At its end remote from the pin 29, the arm 30 is pivotally connected with one end of the cutting chain 10, for example by means of a pin 34 which passes through the end of the arm 30 and the two side links of the last chain link located at said one end of the chain 10. The other arm 31 of the tensioning means 12 is capable of being detachably connected at its end remote from the pin 29 with the other end of the cutting chain, or with the length of chain utilized in the actual cutting operation in those instances, when the chain as a whole is too long for the pipe to be cut. For the purpose of tightening the chain 10 around the pipe 11, there is arranged an externally threaded spindle 35, which is pivotally mounted in the arm 30 and which passes through a bore or a slot in the arm 31 and which carries on one end a nut 36 arranged to cooperate with the side of the arm 31 remote from the arm 30 as an abutment surface and to be tightened during the pipe cutting operation, as the cutting elements 37 cut into the pipe.

The cutting chain of the present invention is a roller type chain, having

side links

38, 39 and pins 40 pivotally connecting the links together and on which pins the circular cutting elements 37, flanked by the

side links

38, 39, are mounted for rotation for cutting engagement with the pipev According to the invention, the distance between the

side links

38, 39 in each chain link of the cutting chain can be adjusted in a manner to maintain a high degree of precision of the cutting chain despite the wear-and-tear experienced thereby. This feature, together with the guide surfaces 32, 33 arranged on the tensioning means to ensure that the ends of the chain 10, or of the length of chain used, are aligned correctly with respect to each other, makes certain that, when the chain 10 is placed around the pipe 11, all the cutting elements 37 used in each cutting operation lie directly on and are caused to work along one and the same line which extends around the periphery of the pipe and in a plane perpendicular to the axis of the pipe. For the purpose of restricting the depth to which the cutting elements 37 are able to cut into the pipe 1] and to prevent the chain 10 from fastening to the pipe 11, or a

side link

38, 39 from rubbing against the pipe on such occasions when the cutting elements penetrate the pipe locally around the inner circumference thereof, there is preferably arranged on either side of each cutting element a support roller 41. The support rollers 41 are rotatably mounted on associated pins 40 and are preferably located between the outermost side links 39, as illustrated in FIG. 3.

With the preferred embodiment of the cutting chain illustrated in FIG. 3, adjustment of the distance between the side links is made possible by the fact that each pin 40 is provided at one end thereof with a preferably cylindrical head 42 and at its other end 43 is in threaded engagement with the outmost side link 39 on the opposite side of the chain l0, thereby preventing the pin 40 from rotating relative the

side links

38, 39 together with the cutting elements 37, to avoid unnecessary wear-and-tear. To facilitate adjustment of the distance between the

side links

38, 39, the head 42 is suitably provided with a slot 44 or the like for receiving a suitable turning tool, such as a screw driver. The set position of the

side links

38, 39 is locked by means of a locking nut 45 located on the end 43 of the pin 40. The locking nut 45 is preferably provided with a cylindrical outer surface such that with respect to its external configuration the nut conforms substantially with the head 42, and is provided on only a limited portion thereof with spanner engaging surfaces or the like for cooperation with a conventional wrench for tightening the locking nut. In this connection, the end of the arm 31 remote from the pin 29 is preferably fork shaped, the limbs 46 of the fork being provided with hooks or recesses 47 conforming to the heads 42 and the lock nuts 45 of the chain pins 40.

It lies within the purview of the invention to cause the cutting chain 10 to move around the pipe 11 in one and the same direction when cutting the pipe. It is preferred, however, as will be evident from the drawing, to cause the cutting chain 10 to move backwards and forwards peripherally around the pipe by means of a pressure cylinder or engine 14, the length of stroke of the piston rod 27 being adjusted so that each cutting element 37 moves through a distance which at least slightly exceeds the distance between adjacent cutting elements. The cutting chain 10 is suitably tightened, by

means of the nut 36, during the cutting operation, for example at the end of the outward stroke of the piston rod 27.

The known means for giving the piston rod 27 a continuous reciprocating movement is illustrated in FIG. 4,

in which the casing, indicated by the reference numeral 48 in FIG. 1, has been removed from the engine 14 to expose the engine components. The pressure medium, in the illustrated example compressed air, used to drive the engine 14 enters through an inlet 49 which is provided with a bayonet coupling and which leads to a conventional, pressure controlled three-way directional valve 50, from which extend

pipes

51 and 52 for conducting compressed air to the cylinder 26 on either side respectively of the piston (not shown) carrying the piston rod 27.

The directional valve is controlled by two conventional low pressure-controlled

diaphragm valves

53, 54, which, when the piston rod 27 reaches its outermost and innermost positions, switches the compressed air passage in the directional valve 50 so that compressed air is supplied to the cylinder 26 thorugh the

line

52 or 51 respectively. Working air is supplied to the valve 54 through a line 55, via a manually operated start valve 56, while working air is supplied to the valve 53 through

lines

57, 58 directly from the inlet 49. A line 59 extending from the line 57 is arranged to conduct compressed air to the start valve 56. The

diaphragm valve

53, 54 detects the drop in pressure in the cylinder 26 at the end of the inward and outward stroke of the piston, via the air lines 60 and 61 respectively, while working air from the

valves

53 and 54 is passed to the directional valve 50 via the

line

62 and 63. With this arrangement the piston rod 27 will thus continue to move backwards and forwards, provided that compressed air is supplied through the inlet 49 and the operating button 64 of the start valve 56 is in start position, while the piston rod 27 will stop at its inner position, when the operating button 64 is moved to its stop position.

The invention is not restricted to the described and illustrated example, but can be modified within the scope of the following claims.

I claim:

1. In an arrangement in pipe cutting apparatus of the type comprising a number of circulr cutting elements mounted on a chain of the roller type which is capable of being placed around a pipe to be cut and which has side links pivotally mounted on pins on which the circular cutting elements, flanked by the side links, are mounted for rotation for cutting engagement with the pipe, tensioning means for connecting together the ends of the length of chain utilized in effecting a cutting operation and for tightening the chain around the pipe, and means connected to the tensioning means for causing the chain to move reciprocably in the peripheral direction of the pipe and including attachment means secured to the pipe and a detachable linear piston engine capable of being coupled between the attachment means and the tensioning means, an improvement comprising means for adjusting the distance between the side links of each chain link and for locking the side links in the adjusted position, said tensioning means including parts which are provided with co-acting guide surfaces arranged to bring the ends of the chain into correct alignment with each other, thereby ensuring that all cutting elements are placed on and cut along one and the same line around the periphery of the pipe.

depth to which the cutting elements cut into the pipe.

4. An arrangement according to claim 1 wherein said parts with the co-acting guide surfaces include two pivotably connected arms each connected to a respective end of the chain, one of said arms including spaced lugs, the other arm being fitted between said lugs, said co-acting guide surfaces being constituted by flat abutment surfaces in facing contact on said lugs and other arm.

Claims

2. An arrangement according to claim 1, wherein each pin includes at one end thereof a cylindrical head the other end of said pin being in threaded engagement with the outermost side link on the opposite side of the cutting chain, and means comprising a cylindrical locking nut mounted on the end of the pin projecting outwardly of said outermost side link, to prevent rotation of the pin together with the circular cutting element.

3. An arrangement according to claim 1 support rollers mounted for rotation on the pins for restricting the depth to which the cutting elements cut into the pipe.