TUBE CUTTING APPARATUS

Abstract: A tube cutting apparatus by means of which out of a tubular blank (3) at least one tubular piece (11) is cut by using a cutting device (26) effecting to the outer surface of the tubular blank. A stopping piece (14) is held inside the tubular blank (3) at the cutting device, the said stopping piece being held at its position by means of a member fastened through the rear end of the tubular blank (3) to the body construction (1) of the tube cutting apparatus. The member (15) holding the stopping piece (14) is flexible such as wire rope, chain or the like. The flexible member (15) is connected to a collecting member (16) affixed to the body construction (1) of the tube cutting apparatus.

Description: TUBE CUTTING APPARATUS This invention relates to tube cutting apparatus more closely defined in the preamble of the claim 1. EP-patent application 168 334 describes an apparatus for such purposes comprising a stopping piece, which is positioned inside the tubular blank to reach the cutting device by means of a rigid bar. This kind of apparatus is unadvantageous as far as both the function and the construction are concerned. The positioning of the stopping piece inside the tubular blank is time consuming. Further the construction of the apparatus is complicate, because the space required by the bar must be taken into account. In other words much space is required to the bar itself and for the positioning of the stopping piece by means of the bar devices having a long operating range are needed. The purpose of this invention is to provide such an apparatus for tube cutting, by means of which the holding of the stopping piece at the cutting point can be executed by a simple and reliable manner. The apparatus is especially suitable for the cutting of rigid tubular blanks, from which for instance blanks for tubular board barrels can be mentioned. Such long blanks are delivered from the manufacturer to the user who then cuts the blanks to the predetermined lenghts. For instance when the said blanks for tubular board barrels are concerned the positioning of the stopping piece into the tubular blank is advantageous to achieve good cutting quality. The tubular board blank is namely made of multiple layered board and the inner layers tend to peel off if there is no stopping piece arranged inside the tubular blank to prevent this. The result would be bad cutting quality in the form of rough inner surface at the end of the tubular board barrel. For the above mentioned purpose the apparatus is mainly characterized by features represented in the claim 1. In order to place and to hold the stopping piece at the cutting device alternatively two methods or the combination of the same can be used. In the first instance, the flexible member can be selected from the group of organs, which can take a certain amount of bearing stress, such construction for the flexible member being chain. Nowadays there are commercially available chains, which can take certain amount of bearing stress without being rotated at the connecting links between the parts of the chain with relation to each other. Further some chains are constructed so, that the rotation between the parts of the chain with relation to each other is limited. Thus the chain can be bent to reach a certain degree of curvature. This kind of flexible members make it possible to push the stopping piece from the rear end of the tubular board blank inside the said blank to reach the cutting device as far as the friction characterics between the stopping piece and the tubular blank material are chosen suitably. Another alternative to place and to hold the stopping piece at the cutting device is to use gaseous pressure intermediate medium such as pressurized air causing a force effecting to the rear end at the said stopping piece. This force moves the stopping piece to reach the cutting device and the said stopping piece is held at its position by the said flexible member causing counter force to the said force caused by the pressure intermediate medium. By using this alternative it is possible that the flexible member is a wire instead of a chain. The wires cannot usually take bearing stress effected to them. Accordingly a combination of the chain and pressure intermediate medium can be used. By stopping the feeding of the flexible member inside the tubular blank when the stopping piece reaches the cutting device, and by fastening the flexible member to the body construction of the apparatus so, that the lenght of the flexible member between the stopping piece and the point of attachment is constant during the successive cuttings of the tubular blank, the stopping piece is held at its position at the cutting device. For . instance the tubular board blank mentioned hereabove is fed successively towards the cutting device and tubular board barrels with predetermined lenght is cut out of it. During the feeding of the tubular board blank only extension stress caused by the friction forces between the stopping piece and the inner surface of the tubular board blank is effecting to the flexible member. Thus the successive feeds of the tubular board blank do not move the stopping piece from its position at the cutting device, where it has been initially positioned. This can of course be further ensured by means of successive or continuous flow of the pressure intermediate medium in the case when said medium is used. The additional advantageous features of the invention are described in the annexed subclaims. The invention will be described in more detail in the following description with reference to the accompanying drawings. In the drawings Fig. 1 is a perspective view of the apparatus in accordance with the invention. Fig. 2 is a perspective view of the feeding of the stopping piece and Fig. 3 is a partial sectional view of the placement of the stopping piece at the cutting device inside the tubular blank. The apparatus illustrated in Fig. 1 comprises an elongate body construction 1, which is shown partially cut and in which the cutting assembly for cutting the tubular blank 3 (represented by broken lines) is mounted. The body construction 1 comprises vertical rollers 4 acting as means for supporting the tubular blank 3 to be cut. The rollers are aligned one after the other in the longitudinal direction of the tubular blank 3 and are arranged at the both sides of the tubular blank so that the rollers can rotate about their longitudinal axes parallel to the longitudinal axis of the tubular blank 3. The tubular blank to be cut rests on these rollers. The tubular blank 3 to be cut is fed towards the cutting assembly 2 successively in accordance with the length of the pieces to be severed off the tubular blank. The feeding operation is carried out by the feed assembly 5 for the tubular blank and it comprises a pusher head 6, which is arranged to be moved in the direction of the feed (arrow 7) e.g. by means of a belt drive 8 shown in the figure and the pusher head 6 is guided by rails 31 (Fig. 2). The feed assembly comprises further a back stop 9 adjustable in the longitudinal direction of the tubular blank and contacting the front end 10 of the tubular blank 3 after each feeding movement of the pusher head 6 in the feed direction 7. The back stop 9 is coupled to the drive motor of the belt 8 of the pusher head 6 and the motor will stop as the front end 10 of the tubular blank 3 contacts the back stop 9. The apparatus further comprises an intermediate storage 12 for the severed tubular pieces 11. The pieces 11 are transferred from the body construction e.g. by means of a pusher (not shown in the drawings) before a new feeding movement of the tubular blank. In the construction shown by Fig. 1, the pusher head 6 abuts the rear end 13 of the tubular blank 3. It is clear, that the feed assembly 5, e.g. as far as the pusher head 6 is concerned, can be constructionally realized also in various other ways. Fig. 1 shows further an assembly for bringing the stopping piece 14 used in the cutting operation to the cutting point as well as for holding the stopping piece at the cutting point. The stopping piece 14 is a formed piece having a cross section, which corresponds substantially to the cross section of the core hole of the tubular blank 3 to be cut. The stopping piece 14 has usually the shape of a cylinder and its front end in the feed direction is preferably rounded. A flexible elongate member 15, such as a wire rope, a chain or the like is fixed to its rear end in feed direction. The flexible member 15 is connected with a collecting member 16, such as a reel, which is arranged to rotate about a horizontal shaft 17 mounted in the body construction 1. The flexible member 15 is wound and unwound on its outer periphery. The flexible member can be a wire rope or the like. The force needed for the transfer is obtained by blowing air with a air compressing device 18 in to the tubular blank to be cut. The device comprises a tank 19 and a hose 20 for the compressed air as well as a hole 21 going through the pusher head 6 and in connection with the core hole of the tubular blank 3 to be cut. By means of the compressed air, a force directed onto the rear surface of the stopping piece 14 is obtained and the stopping piece 14 moves under this influence from the rear end 13 of the tubular blank 3 to the cutting point and at the same time the flexible member unwinds from the collecting member 16, whose rotation about - its shaft 17 is so restricted, that the stopping piece 14 stops at the cutting point held by the flexible member. The flexible member extends through the pusher head 6 for example via the hole 21 or via a separate hole (not shown in Fig. 1). The abutting surface of the pusher head 6 is dimensioned at the rear end 13 of the tubular blank 3 so, that it covers the core hole of the tubular blank thus increasing the effect of the compressed air on the stopping piece. The stopping piece 14 can be brought to the cutting point also by merely pushing with a chain. There are commercially available chains, by means of which pushing forces directed to the chain can be transmitted at least to a certain extent. As the outer surface of the stopping piece is formed so that its frictional characteristics will be adapted to the characteristics of the inner surface of the tubular blank to obtain a minimum friction between the inner surface of the tubular blank 3 and the outer surface of the stopping piece 14, the chain is not subjected to any greater bearing stress. Fig. 1 shows further the storage for stopping pieces on the right side of the compressed air device 18. The storage contains various stopping pieces 14 ' , whose dimensions fit with the tubes of different sizes. A new tubular blank can be fed onto the rollers 4 of the apparatus e.g. in the direction of arrow S. The cutting assembly 2 comprises an upright beam 22 fixed on the body construction 1 and bearing at -its upper portion a horizontal beam 23 directed towards the body construction 1. Underneath the horizontal beam 23, a moving beam 24 is pivotally fixed to the upright beam 22 (point of articulation 25) and it is pivotable in a vertical plane. The pivotal movement and at the same time the feed movement of the cutting device 26 towards the central axis of the tubular blank 3 is effected by an operational device 27., such as a pneumatic cylinder, which is disposed between the horizontal beam 23 and the moving beam 24. The cutting assembly 2 well as assemblies associated therewith are described in more detail in a co-pending Fl-patent application 860629 by the same applicant, relating to a cutting apparatus. Especially Fig. 2 presents the positioning of the stopping piece 14 to the cutting device 26. Fig. 2 shows the combination of the pressurized air and the use of wire rope as the flexible member 15. The abutting surface 28 of the pusher head 6 is constructed so that the core holes of the tubular blanks of different diameters are covered at the rear end 13 of the same. The pressurized air is effecting to the rear end 30 of the stopping piece 14 to which the flexible member 15 is affixed, via a channel 29 through the pusher head 6. The channel 29 is connected to a pneumatic hose 20 which is connected to the tank 19 (Fig. 1). Fig. 2 further shows the belt drive 8 of the pusher head 6, by means of which the pusher head is successively moved towards the cutting device 26 in order to feed the tubular blank 3 towards the back stop 9 and thus cut the tubular blank into pieces having a predetermined lenght. The collecting member 16 is locked during the feedings so that it does not rotate. Thus the stopping piece 14 is held at the cutting device due to the fact that the flexible member 15 is effected by extension stress. The reference numeral 31 show the guiding rail for the pusher head 6. Fig. 3 shows the another alternative for the flexible member 15 namely the chain. Some commercially available chains can take a certain amount of bearing stress effected to them. So it is possible by selection of the material for the stopping piece 14 so that the friction between the stopping piece 14 and the inner surface of the tubular blank 3 slight to push the stopping piece 14 by means of the flexible member 15 inside the tubular blank. The rear end of the stopping piece 14 comprises a rapid connector 32. The free end of the flexible member 15 comprises a cylindrical part 33 having a transversal groove 34. The stopping piece itself has a hole 35 in the rear end 30. The hole 35 comprises fasteners movable in the radial direction such as spring-loaded balls 36. Thus the stopping piece can be easily and rapidly changed to fit the new size of the core hole of the tubular blank 3 to be cut from the storage containing stopping pieces 14' . The front end 31 of the stopping piece 14, 14' is rounded having for instance spherical form. The material of the stopping piece can be for instance nylon, polyurethane and even steel can be used in some cases.

Claims: Claims: 1. Tube cutting apparatus by means of which out of a tubular blank (3) at least one tubular piece (11) is cut by using a cutting device (26) effecting to the outer surface of the tubular blank whereby a stopping piece (14) is held inside the tubular blank (3) at the -cutting device, the said stopping piece being held at its position by means of a member fastened through the rear end of the tubular blank (3) to the body construction (1) of the tube cutting apparatus, c h a r a c t e r i z e d in that the member (15) holding the stopping piece (14) is flexible such as wire rope, chain or the like. 2. Tube cutting apparatus in accordance with claim l, c h a r a c t e r i z e d in that the flexible member (15) is connected to a collecting member (16) affixed to the body construction (1) of the tube cutting apparatus. 3. Tube cutting apparatus in accordance with the claims 1 and 2, c h a r a c t e r i z e d in that the collecting member (16) comprises an organ (17) for adjusting the feeding lenght of the flexible member (15) and thus for holding the said flexible member (15) at the cutting device (26). 4. Tube cutting apparatus inaccordance with the claims 1-3, c h a r a c t e r i z e d in that the collecting member (16) is a reel arranged to be rotated about a suitably horizontal shaft (17) connected to the body construction of the apparatus and that the apparatus comprises locking means for locking the reel from rotating. 5. Tube cutting apparatus in accordance with claim l, σ h a r a c t e r i z e d in that the flexible member (15) is led through the hole (21) of the pusher head (6), which is arranged to push the tubular blank successively towards the cutting device (26). 6. Tube cutting apparatus in accordance with claim l, c h a r a c t e r i z e d in that the organ for placing the stopping piece (14) is the flexible member suitably a chain and/or gaseous pressure intermediate medium arranged inside the tubular blank (3). 7. Tube cutting apparatus in accordance with claims 5 and 6, c h a r a c t e r i ' z e d in that the pressure intermediate medium is arranged inside the tubular blank through the hole (29) in the pusher head (6), the abutting surface (28) of the said pusher head (6) being arranged so, that it covers the core hole of the tubular blank (3). 8. Tube cutting apparatus in accordance with claim l, c h a r a c t e r i z e d in that the stopping piece (14) comprises a rapid connector (32) at its rear end for connecting the flexible member (15) demountably. 9. Tube cutting apparatus in accordance with claim l, c h a r a c t e r i z e d in that the material of the stopping piece is nylon, polyurethane or steel or combination of the same.

Inventors: TAKANIEMI TAUNO, TAKANIEMI, TAUNO
Applicants: VENDMATIC OY
Application year: 1987
Main classification: B26D3
IPC codes: B26D3