Apparatus for forming a rectangular collar at the end of a pipe

Abstract: The invention relates to a procedure and an apparatus for forming a rectangular collar at the end of a pipe (16) by shaping it by means of a forming element (8) which is moved in the axial direction of the pipe (16) towards the pipe (16) and rotated along the edge surface of the pipe end about the longitudinal axis of the pipe. In the procedure, a conical collar is first produced, whereupon the forming element (8) is moved in the axial direction of the pipe away from the pipe (16) and turned to a position where its forming face is substantially perpendicular to the longitudinal axis of the pipe, whereupon a rectangular collar is formed. The apparatus of the invention is provided with turning means (15) allowing the forming element to be turned about its fulcrum (9) into a first position, where the surface of the forming element is at an acute angle to the direction of the longitudinal axis of the pipe and the forming element (8) is supported by a first bearing surface (13), and into a second position, where the surface of the forming element is substantially perpendicular to the direction of the longitudinal axis of the pipe and the forming element (8) is supported by a second bearing surface (14).

Description: The present invention relates to an apparatus for forming a rectangular collar at the end of a pipe according to the introductory part of claim 1. In joining pipes together, a possible alternative is to form perpendicular flanges at the ends of the pipes to be joined, which are then coupled together. In the case of pipes that can be plastically worked up, the flange can be formed by suitably shaping the pipe end. However, if the pipe diameter and the thickness of the pipe wall is large, a considerable force is needed for the shaping operation. Forming a collar on a pipe with a diameter of 200 - 400 mm requires a force of several thousand kilopond. In this case, the bearing elements transmitting the force constitute an important part of the functional whole. In a previously known solution (FI A 870799), a collar at an angle of 35-40° is first formed at the pipe end, then the forming cone is replaced or an auxiliary forming head is mounted on it, whereupon a final rectangular collar is formed. The cone is held in a chuck by its shaft, the chuck being rotatably mounted on the frame. In another known device, the forming cone can be mounted at different positions in the chuck to permit the formation of collars on pipes of different sizes. In the known solution, the forming cone must be fitted anew between the first and second stages of the operation, and the cone is only supported by one end. Moreover, a separate fit is needed for each pipe size. Another previously known solution (GB 1 580 285, closest prior art) comprises the sequential steps of arranging a swaging roller in an initial position in which its axis is oblique to the pipe axis, flaring an end portion of the pipe by urging the roller and the pipe wall towards each other in the direction of pipe axis while turning the roller and the pipe relative to each other about the pipe axis, arranging the roller in a final position in which its axis is substantially perpendicular to the pipe axis, and forming the flared portion into a flange by urging the roller and the pipe wall towards each other in the direction of the pipe axis while turning the roller and the pipe relative to each other about the pipe axis. The object of the present invention is to achieve a new apparatus which is fast and simple to operate and in which the axial force is transmitted to the object under shaping via parts properly supported. To accomplish this, the apparatus of the invention is characterized in what is described in the appended claim 1. In an embodiment of the invention, the forming element is attached to a sliding carriage mounted in a tool body and movable in a direction perpendicular to the pipe. Thus, the forming element can be moved to a suitable distance from the pipe axis corresponding to the diameter of the pipe and secured in that distance by means of locking elements. The features of other embodiments of the invention are defined in the dependent claims. In the following, the invention is described in detail by the aid of one of its embodiments by referring to the drawings, in which Figure 1 presents a lateral view of the apparatus of the invention in its first position. Figure 2 presents a detail of Figure 1 taken along section B-B. Figure 3 presents a lateral view of the apparatus of the invention in its second position. Figure 4 presents a detail of Figure 2 taken along section C-C. Figure 5 presents the device of the invention as seen from the direction of the pipe. Figure 6 presents a lateral view of the turning means of the apparatus of the invention. Figure 7 presents the apparatus of the Invention partly sectioned, seen from below. Figure 8 presents a detail of Figure 7 taken along section A-A. Figure 1 shows a sectioned lateral view of the apparatus of the invention. The apparatus is coupled by means of a shaft 1 to a driving gear (not shown) which supports it and rotates the shaft about its central axis, depicted with a broken line and lying parallel to the longitudinal axis of the pipe 16. During the shaping operation, the pipe 16 is held in place by clamping jaws 17. The driving gear also moves the shaft 1 in the direction of the central axis. Attached with bolts 26 to the end of the shaft 1 pointing away from the driving gear is a tool body 2. A wedge 27 is fitted at the junction between the shaft 1 and the tool body 2 to receive the torque. Mounted in the tool body 2 is a sliding carriage 3 which is movable in a direction perpendicular to the longitudinal axis of the pipe 16 and therefore to the axis of rotation of the apparatus, indicated with a broken line. Fixed with screws 21 to the carriage 3 is a nut 5 for a conveyor screw 4 used to move the carriage along a guide track provided in the tool body 2. The other end of the conveyor screw is depicted with broken lines and is described in greater detail in connection with figure 5. On the side facing the pipe end to be shaped, the carriage has a chamber 19 for a forming cone, housing a forming cone 8 acting as a forming element. The forming cone 8 is a truncated cone whose conical surface constitutes the forming face which rolls along the pipe edge 16. The part constituting the forming face is rotatably mounted on its supporting axle on the body 34 of the forming cone, using a double-seat needle bearing construction. The body 34 of the cone is supported by a joint pin 9 at the wider end of the cone, constituting the fulcrum on which the cone turns. The joint pin 9 is fixed to a slide block 10 (figures 7-8) which can move along guides 20 provided in the carriage 3. Attached to the ends of the guides 20 are stop plates 12 to prevent the slide block from coming off the guides. At the narrower end of the cone, the cone body forms a cylindrical projection 33 protruding from the cone and having a radius smaller than that of the narrower end of the cone. The carriage 3 is provided with shoulders 13 and 14 designed to receive the narrow end of the forming cone 8 in its first and second positions, respectively (fig. 3). In figure 1, the forming cone 8 is in its first position, where the forming surface lies at an angle of 45° to the longitudinal axis of the pipe 16 while the cone is supported by the joint pin 9 and shoulder 13. Figure 2 presents a detail of figure 1 as sectioned along line B-B. The projection 33 of the cone body rests in a slot 43 whose width corresponds to the diameter of the projection. The cone is held in place by elastic plungers 11 which are pressed against the circumference of the cylindrical projection from its outer side. In figure 3, the forming cone 8 is in its second position, in which the forming surface is at right angles to the longitudinal axis of the pipe. In this case, the narrower end of the cone leans against shoulder 14 and the cylindrical projection is in slot 44. Correspondingly, the joint pin 9 has now moved further away from the central axis of the pipe. In other respects, figure 3 corresponds to figure 1 and the reference numbers used in the figures are the same for corresponding parts. Figure 4 presents section C-C of figure 3 and shows how the projection rests in the slot 44, with elastic plungers 28 holding the cone in place in the same way as in the first position of the cone as illustrated by figure 2. Figure 5 depicts the apparatus as seen from the direction of the pipe, in a partly sectioned view. The conveyor screw 4 is mounted in the tool body 2 by means of bearings placed at the side opposite to the carriage 3. The journal box of the conveyor screw is fixed with screws 22 to the tool body 2 and the conveyor screw is attached with radial 24 and axial 23 thrust bearings to the journal box. The bearing assembly is locked by a nut 25. To fix the carriage 3 firmly to the tool body 2, the carriage is provided with a socket 31 in which a wedge-shaped locking block 6 is fitted. As illustrated more clearly by figure 7, the locking block is tightened against the carriage and the guide track wall in the tool body by means of a screw 7 so that the carriage is pressed tightly against the opposite wall of the guide track. These locking elements keep the carriages and the forming cone mounted on it in the appropriate distance from the longitudinal axis of the pipe. The carriage and the tool body are preferably provided with markings indicating the carriage positions corresponding to different standard pipe diameters (D139.7, D168.3, D355.6 and D406.4 in figure 5), thus making it easier to carry out the cone setting required for a given pipe size. Figure 7 presents a partly sectioned view of the apparatus as seen from below, and figure 8 shows a section taken along line A-A In figure 7. Provided in the carriage 3 are elastic plungers 29 with a ball 32 at the end, and the slide blocks are provided with corresponding grooves designed to receive the plunger ball 32 when the slide block is in the correct position. In figure 8, the other position of the slide block 10 is depicted with broken lines, in which case the balls of plungers 39 are pressed into the gooves of the slide blocks. To prevent the slide blocks from coming off the guide, the travel of the slide blocks 10 is limited at one end of the guide 20 by the wall 18 and at the other end by a stop plate 12 attached to the carriage by means of fixing screws 30. Figure 6 presents the turning lever 15 used to turn the forming cone 8, showing the lever as attached to the cone in its first position (solid lines) and in the second position (broken lines). The arrows 1, 2, 3 indicate the lever motion from the second position to the first position. According to the invention, the shaping procedure is as follows. The pipe to be collared is fixed in position by means of clamping jaws 17. If the forming cone 8 is not in the distance corresponding to the pipe diameter, the carriage 3 is moved to the required distance by turning the conveyor screw 4 and secured by means of locking blocks 6. The forming cone 8 is engaged with the turning means 15 and turned into its first position, where the forming face of the cone is at an agle of about 45° to the pipe. The turning is performed by first drawing the cone outwards along the guides 20 (arrow 1, figure 6), then inclining the cone (arrow 2) and pushing it inwards (arrow 3). To make a conical collar at the pipe end, the shaft and the forming cone attached to it are moved towards the pipe in its axial direction by means of the driving gear. At the same time, the forming cone is rotated about the longitudinal axis of the pipe by the driving gear. When the axial motion of the forming cone is stopped by the clamping jaw 17 acting as a stopper (figure 1), a conical collar has been formed. The shaft is then moved back away from the pipe to allow the cone to be turned into the second position, in which the forming face is at an angle of about 90° to the longitudinal axis of the pipe. The turning operation is performed in reverse order as compared to the operation described above (arrows 3, 2 and 1 in figure 6). The shaft is then driven again towards the pipe while rotating the cone as before until a rectangular collar has been formed. As the fulcrum 9 of the cone on the one hand and the shoulders 13 and 14 holding the cone on the other hand are located on opposite sides of the pipe surface to be shaped, the force is effectively applied to the pipe.

Claims: Apparatus for forming a rectangular collar at the end of a pipe, comprising a forming element (8) rotatably mounted on its supporting axle and a tool body (2) which bears the forming element (8) either directly or indirectly and which can be moved with respect to the pipe (16) in the direction of its longitudinal axis so as to bring the forming element (8) into contact with the end of the pipe (16) and to permit it to be shaped, whereby the apparatus is provided with turning means (15) allowing the forming element to be turned about its fulcrum (9) into a first position, where the surface of the forming element is at an acute angle to the direction of the longitudinal axis of the pipe, and into a second position, where the surface of the forming element is substantially perpendicular to the direction of the longitudinal axis of the pipe, characterized in that in the first position the supporting axle of the forming element (8) is supported by that fulcrum at the one end and a first shoulder (13) at the other end, and in the second position the supporting axle of the forming element (8) is supported by the fulcrum at that one end and a second shoulder (14) at the other end, and in that the supporting axle of the forming element is turnably fixed at the fulcrum. Apparatus according to claim 1, characterized in that it is provided with guides (20) along which the fulcrum (9) of the forming element (8) can be moved in a direction essentially perpendicular to the axis of the pipe (16) before and after the turning of the forming element (8). Apparatus according to claim 1 or 2, characterized in that it is provided with retaining elements (11,28,29,39) fitted in conjunction with the fulcrum (9) and the bearing surfaces (13,14) to keep the supporting axle of the forming element in place. Apparatus according to claim 1 - 3, characterized in that the forming element (8) together with its supporting axle and retaining elements is attached to a sliding carriage (3) mounted in the tool body (2) and movable at right angles to the axis of the pipe so as to allow the distance of the forming element (8) from the longitudinal axis of the pipe (16) to be adjusted so that it corresponds to the diameter of the pipe (16) to be collared. Apparatus according to claim 4, characterized in that it is provided with locking elements (6,7) fitted between the carriage (3) and the tool body (2), by means of which the carriage (3) is secured at the required distance. Apparatus according to claim 1 - 5, characterized in that the fulcrum (9) is located outside the pipe (16) or its imagined extension.

Inventors: PAAKKUNAINEN MATTI, PAAKKUNAINEN, MATTI
Applicants: GS HYDRO OY, GS-HYDRO-OY
Application year: 1993
Main classification: B21D19
IPC codes: B21D19