FIELD OF THE INVENTION

[0001] The invention relates to a grinding member and its use in a machining device. The machining device may be used for puncturing a pipe liner installed in a thicker pipe of a pipe assembly and for grinding the edges of the opening from a thinner pipe of the pipe assembly.

PRIOR ART

[0002] Pipe systems, for example drainpipe systems of buildings, are typically renovated by re-placing the pipes with completely new ones or by coating the inner surfaces of existing pipes with an appropriate coating technique and coating material.

[0003] One coating technique is what is called a lining technique, in which the pipe liner is slipped into the drain to be renovated and impregnated with special epoxy resin. When epoxy resin is hardened, a continuous and tight pipe is formed which is, for example, self-supporting, acid-proof, food-grade and environmentally friendly. The wall thickness of the pipe liner is, depending on the size of the pipe, 2 to 4 mm, and its smooth inner surface guarantees excellent flow properties. The durability, environmental safety and service life of the pipe having been installed in place and hardened are comparable with corresponding properties of new pipes.

[0004] When the pipe liner has been installed for instance in the vertical, thick main line of a drainpipe system, all joints from the main line to the thinner branch lines connected there-to are clogged. The joints between the main line and the branch lines must thus be provided with holes to enable waste waters to flow from the branch lines to the main line. In one solution, the holes are made via the main line with, for instance, a robot drill. Robot drills are large in size, expensive and complex devices, the use of which requires special expertise of the user. The hole may be inadvertently drilled partly or completely at a wrong point, and even if the hole were drilled at the right point, the edges of the drilled hole often remain rough. Waste may adhere to the rough points of the joint, and in the course of time, it may accumulate into thicker deposits and even clog the drain. Also, there should not be any stagnant water remaining at the rough points of the joint. Furthermore, robot drills are usually not suitable for use in main lines having bends. The size of the robot drill may prevent the drill from being moved past the bends in the main line to that point of the main line where the hole should be drilled.

[0005] Fl patent application no. 20094576 discloses another possibility to open the joint between the main line and a branch line. The tool and the method presented in the application can be used to make renovation of pipe systems with the coating technique more efficient. The application discloses a machining device comprising an elongated spindle the outer periphery of which is provided with spaced apart, radially protruding grinding members. The grinding members centre the spindle of the machining device in the pipe and, in addition, grind the inner surface of the pipe. The grinding members are fastened to grooves on the outer periphery of the spindle by means of fastening screws. The machining device is moved and rotated in the pipe by means of a cable attached to the spindle.

[0006] The grinding members of a machining device wear fast and they must be frequently re-placed with new ones. Detaching the worn grinding members from the spindle of the machining device and attaching new grinding members to the spindle of the machining de-vice is time-consuming when the grinding members are fastened to the outer periphery of the spindle with screws.

SUMMARY OF THE INVENTION

[0007] With the solution according to the invention, the working time that goes to replacing grinding elements of a machining device can be made significantly shorter, whereby working becomes more efficient.

[0008] The grinding member according to the invention comprises:

- an elongated support profile, the cross-section of the support profile comprising a vertical direction and a lateral direction, whereby the cross- section of the support profile has at least one portion the greatest dimension of which is, in the lateral direction, greater than the corresponding greatest dimension, in the lateral direction, of the portion above it in the vertical direction, whereby the support profile can be engaged with a groove having a corresponding cross-section

- an elastic grinding plate fastened to the portion positioned highest in the vertical direction of the cross-section of the support profile and protruding from the upper surface of the support profile. [0009] The grinding member is applicable to a machining device comprising an elongated spindle on the outer periphery of which the grinding members are arranged.

[0010] The invention also relates to the use of a grinding member in a machining device which may be used for puncturing a pipe liner installed in a thicker pipe of a pipe assembly and for grinding the edges of the opening from a thinner pipe of the pipe assembly.

[0011] The outer periphery of the spindle of the machining device is provided with grooves in the longitudinal direction of the spindle. The cross- sectional shape of the grooves corresponds to that of the support profile of the grinding member. The support profile of the grinding member can thus be pushed from either of the end surfaces of the spindle into the groove on the outer periphery of the spindle, which engages the support profile and thus the entire grinding member with the groove. The grinding members can be engaged against movement of the spindle in the longitudinal direction by means of an end plate fastened to one of the end surfaces of the spindle. In that end surface of the spindle that is opposite to the end plate, the grooves may be closed. The grooves may also extend over the whole length of the spindle, whereby the open ends of the grooves are closed with an end plate on each end surface of the spindle.

BRIEF DESCRIPTION OF THE FIGURES

[0012] In the following, the invention will be explained in greater detail with reference to the embodiments shown in the attached drawings.

[0013] Figure 1 shows a machining device in which a grinding member according to the invention can be used.

[0014] Figure 2 shows a variation of the machining device of Figure

1.

[0015] Figure 3 shows a grinding member according to the invention and a spindle of a machining device, on which spindle the grinding member is mounted.

[0016] Figure 4 shows a side view of the machining device of Figure

2.

[0017] Figures 5 to 9 show cross-sectional views of using a machining device for making a hole at the branch point of a pipe joint and for grinding the edges of the hole. DESCRIPTION OF PREFERRED EMBODIMENTS

[0018] Figure 1 shows a machining device 10 in which a grinding member according to the invention can be used. The machining device 10 is typically used for puncturing a pipe liner installed in a thicker pipe of a pipe assembly and for grinding the edges of the opening from a thinner pipe of the pipe assembly.

[0019] The machining device 10 comprises an elongated, cylindrical spindle 11 the outer surface of which is provided with spaced apart radial, elastic, plate-like grinding members 100. The grinding members 100 are preferably arranged on the outer periphery of the spindle 11 , symmetrically relative to the axis of revolution of the spindle 11. One task of the grinding members 100 is to position the spindle 11 inside the pipe and to keep the longitudinal axis of the spindle 11 in the direction of the longitudinal axis of the pipe. The grinding members 100 are attached by their lower ends to grooves 20 in the spindle 11. One end surface of the spindle 1 is provided with a cable 15, one outer end of which (not shown) may be provided with a device rotating the machining device 10, for example a motor that rotates the machining device 10 at a suitable speed. The rotation speed of the spindle 11 of the machining device 10 may be, for instance, 1 000 to 4 000 RPM. The cross-section of the spindle 11 is preferably a circle, but it could also be something else, such as a polygon.

[0020] Figure 2 shows a variation of the machining device shown in Figure 1. The difference in relation to the machining device of Figure 1 is here that one end surface of the spindle 11 is provided with a circular plate 30 in the middle of which there is preferably a spike 31. The surface of the plate 30 is provided with material or surface shapes that grind or chip material. There may be hard metal pieces, for instance, attached to the surface of the plate 30, or the surface of the plate 30 may have patterns suitable for machining material, for example sharp serrated patterns. The plate 30 is typically used for puncturing a pipe liner installed in a thicker pipe of a pipe assembly from a thinner pipe of the pipe assembly. The grinding members 100 centre the spindle 11 in the middle of the pipe and keep the axis of revolution of the spindle 11 in the direction of the longitudinal axis, whereby the grinding members 100 also serve as control means for the material-removing plate 30. [0021] Figure 3 shows a grinding member according to the invention and a spindle of a machining device, on which spindle the grinding member is mounted. The grinding member 100 is shown in section B, the spindle 11 of the machining device is shown in section A, and sections C, D and E show alternative embodiments for the support profile of the grinding member. The grinding member 100 shown in figure B comprises an elongated support profile

110 and an elastic grinding plate 120 attached to the support profile 10. The sup-port profile 110 comprises, in the embodiment of figure B, an upper portion

111 with a rectangular cross-section and a lower portion 112 with a circular cross-section. In the middle of the upper portion 1 1 of the support profile 110, there is a slot 111A extending downwards from the upper surface of the upper portion 111 , into which slot 111A the grinding plate 120 is fastened preferably with crimp connection by one of its edges. The cross-section of the support profile 110 has a vertical direction S1 and a lateral direction S2. The greatest dimension of the cross-section of the lower portion 112 of the support profile 110 is, in the lateral direction S2, greater than the corresponding dimension of the upper portion 111. In this way, the support profile 110 engages with the groove 20 of the spindle 11 against radial and peripheral movement of the spindle 1 when the support profile 0 is pushed into the groove 20 from either of the end surfaces of the spindle 11.

[0022] Sections C, D and E in Figure 3 show three alternative embodiments for the support pro-file of the grinding member. In the embodiment shown in section C, the cross-sections of both the upper portion of the support profile 110 and the lower portion 112 of the support profile 110 are rectangular. In the embodiment of section D, the cross-section of the upper portion 111 of the support profile 110 is also rectangular but the cross-section of the lower portion 112 of the support profile 110 is trapezoid. In the embodiment shown in section E, the cross-sections of both the upper portion 1 of the support profile 110 and the lower portion 112 of the support profile 110 are again rectangular but, in addition, there is a rectangular portion below the lower portion 112. In the embodiments of sections B, C, D and E, the greatest dimension of the cross-section of the lower portion 112 of the support profile 110 is, in the lateral direction S2, greater than the corresponding dimension of the upper portion 111. The cross-section of the support profile 110 may be anything, but it must have at least one portion the greatest dimension of which is, in the lateral direction S2, greater than the corresponding dimension of the up- per portion 111 above it, so that the support profile 110 can engage with the corresponding groove 20 in the spindle 11 against radial and peripheral movement of the spindle 11.

[0023] The grinding plate 120 is preferably a rectangular piece and it preferably comprises a grinding belt which may be reinforced on its smooth side for instance with rubber or Kevlar, which gives the grinding plate 120 elastic flexibility and improves the strength of the grinding plate 120, for example against tearing. Elastically flexible grinding plates 120 similar to each other are preferably positioned symmetrically on different sides of the outer periphery of the spindle 11 , whereby the grinding plates 120 centre the spindle 1 together in the middle of the pipe to be machined in each particular case. The grinding plates 120 also preferably serve as means that remove material from the joint of the pipe assembly (and also from other parts of the pipe to be machined) when the spindle 11 is rotating.

[0024] Section A in Figure 3 shows only one of the longitudinal grooves 20 spaced apart on the outer periphery of the spindle 1. The cross- sectional shape of the groove 20 corresponds to the cross-sectional shape of the support profile 110 of the grinding member 100. The groove 20 corresponds, in this case, to the cross-sectional shape of the support profile shown in section B, whereby the groove 20 comprises an upper part 21 having a rectangular cross-section and opening to the outer periphery of the spindle 11 , and a circular lower part 22 remaining inside the spindle 11. In a case where the cross-sectional shape of the support profile 110 is something else, also the shape of the groove 20 in the spindle 11 is arranged to be corresponding, so that the support profile 110 can be pushed from either end surface of the spindle 11 into the groove 20, with which it engages against radial and peripheral movement of the spindle 11.

[0025] Figure 4 shows a side view of the machining device of Figure 2. The plate 30 has fastening members 32 for fastening the plate 30 to the spindle 11 of the machining device 10. The figure also shows end plates 40, 41 to be positioned on the end surfaces of the spindle 11 and used for engaging the support profiles 110 against longitudinal movement of the spindle 11. The end plates 40, 41 are preferably fastened to the end surfaces of the spindle 11 by screws. The grinding member 100 formed of the support profile 110 and the grinding plate 120 can be replaced very fast. First, the end plates 40, 41 are detached, and after that, the used grinding members 100 are pushed out of the grooves 20 from the support profiles 110. Subsequently, the new grinding members 100 are pushed into the grooves 20 from the support profiles 110, and the end plates 40, 41 are reattached. Here, it is also feasible to use only one end plate 40, whereby the other ends of the grooves 20 are closed or the other end plate 41 is kept in place all the time. The end plates 40, 41 are preferably fastened to the end surfaces of the spindle 1 by screws.

[0026] Figures 5 to 9 show the use of a machining device for machining the material of the joint of the pipe assembly to be renovated. The pipe assembly comprises a thicker pipe 201 , such as the main line of a drainpipe system coated by, for example, the lining method. As a consequence of the coating, a pipe liner 202 clogs a branch line 203 from the flat. Therefore, the pipe liner 202 must be provided with a hole so that the branch line 203 can be taken into use again. In order to make the hole, the machining device 10, at the end of which a plate 30 is engaged, is inserted into the branch line 203 by using a cable 15. The branch line 203 may have several bends at up to 90 degrees. The machining device 10 must be dimensioned in such a way with regard to, for example, the length, diameter, flexibility of the grinding members 100 and attachments to be fastened to the device, such as the plate 30 or control device 40, that it can be pushed through the 90-degree bends. When the machining device 10 is pushed forward in the branch line 203 by means of the cable 15, the machining device 10 is simultaneously rotated on the cable 15, whereby the machining device 10 grinds the walls of the branch line 203 with the grinding plates 120 of the grinding members 100. Before this, coating agent suitable for coating the branch line 203 may have been applied to the walls to be ground. When the machining device 10 reaches the joint between the main line 201 and the branch line 203, the plate 30, which is centred by the grinding members 100 of the machining device 10 in the middle of the branch line pipe 203, begins to make a hole in the pipe liner 202. Since the diameter of the plate 30 is for instance 10% smaller than the inner diameter of the branch line 203, there remains, in accordance with Figure 6, a "collar" at the joint after the drilling, and it must be ground off to achieve acceptable finishing quality.

[0027] The thinner branch line 203 is here connected to the thicker branch line 201 at an angle of about 45 degrees, whereby the machining device 10 with a relatively short length tends to turn uncontrollably when it arrives from the thinner branch line 203 in the thicker branch line 201. The machining device 10 must be relatively short because moving a long, stiff machining device 10 through the bends in the branch line 203 is not possible. To be able to grind the hole edge, particularly the lower edge, properly, it is necessary to be able to control the tendency of the machining device 10 to turn uncontrollably by using a control device. Controlling may involve either turning the grinding machine 10 away from the axial direction of the branch line 203 or keeping the axis of revolution of the grinding members 100 of the machining device 10 in a particular direction, for instance in the axial direction of the branch line 201.

[0028] Figure 7 shows how the collar of the lower edge of the hole can be ground smooth by utilizing a control device 40 attached to the machining device 10, the control device corn-prising, in this example, a cable 41 and a weight 42. The weight 42 presses the machining device 10 controllably downwards against the lower edge of the hole, whereby the collar can be ground off.

[0029] Figure 8 shows how the collar of the upper edge of the hole can be ground smooth by utilizing the control device 40 attached to the machining device 10, the control device corn-prising, in this example, only a cable 41. By pulling the cable 41, for instance manually, the machining device 10 can be pressed controllably against the upper edge of the hole, whereby the collar at the upper edge is ground off.

[0030] Figure 9 shows an alternative control device 40 which forces the machining device 10 to assume the longitudinal direction of the branch line 203 also when the machining device 10 has been partially pushed into the main line 201 , away from the branch line 203. The control device 40 is preferably such that it can be taken into use (activated) after the machining device 10 has been moved to the joint to be machined. It will be obvious to a per-son skilled in the art that it is feasible to construct a plurality of different control devices which meet the functional requirements set for the device and presented herein.

[0031] The invention is not intended to be confined merely to the presented embodiments but details of the invention may vary within the inventive idea of the application.