Patent Application
20220297250
The present invention relates to an alignment tool to be used when mounting a flexible tube between two adjustable pipe ends. By using the alignment tool, the mechanical stress on the flexible tube can be reduced. The alignment tool may e.g. be used when connecting an exhaust manifold to e.g. an exhaust pipe or a silencer with a flexible exhaust tube.
Heavy vehicles, such as trucks, busses, construction equipment vehicles and others, are mostly provided with a larger diesel engine. The diesel engine is suspended in the chassis with vibration dampers in order to reduce vibrations from the engine and to minimize the propagation of vibrations into the vehicle. In some vehicles, the exhaust pipe and parts of the exhaust system may be attached to another part of the vehicle, where the chassis and the other part are movable with respect to each other.
Such an example is a truck, where the engine is suspended in the chassis and the exhaust pipe is attached to the rear of the cabin. The cabin is suspended on the chassis with springs and dampers in order to reduce vibrations from e.g. an uneven road acting on the cabin. The relative movement between the chassis and the cabin may be relatively large, and necessitates the use of a flexible metal exhaust tube in the exhaust system of the truck, in order to reduce vibrations from the engine to the exhaust system and to avoid that the exhaust pipe brakes. Without a flexible exhaust tube, the complete exhaust system would have to move with the engine and not with the cabin.
One problem with a flexible exhaust tube is that it is exposed to severe stress due to vibrations from the engine, relative movement between engine and cabin, and heat from the exhaust gas. This means that the flexible exhaust tube must be replaced every now and then, which takes time and cost. It is thus of advantage to be able to mount the flexible tube in an optimal manner in order to reduce the stress imposed on the flexible tube.
US20150211666 discloses an alignment device for use in aligning and positioning two stiff pipes with pipe ends before joining them together using a mechanical locking device that completely surrounds the pipe ends. This alignment device fixates the two rigid pipe ends relative each other, such that the mechanical locking device can be attached.
There is thus room for an improved alignment tool adapted for flexible tubes.
An object of the invention is therefore to provide an alignment tool for mounting a flexible tube between two pipe ends. A further object of the invention is to provide an improved method for mounting a flexible tube between two pipe ends.
The solution to the problem according to the invention is described in the characterizing part of claim 1 regarding the alignment tool and in claim 11 regarding the method. The other claims contain advantageous further developments of the inventive alignment tool and method.
In an alignment tool for mounting a flexible tube between a first pipe end and a second pipe end, where the alignment tool is adapted to be used to align the first pipe end to the second pipe end, the object of the invention is achieved in that the alignment tool is provided with a semi-circular body having a diameter corresponding to the diameter of the flexible tube, where the length of the alignment tool corresponds to the length of the flexible tube, and that the alignment tool is adapted to bear on the flexible tube during the mounting of the flexible tube between the first pipe end and the second pipe end.
With the alignment tool according to the invention, the flexible tube can be mounted in an optimal position between the first pipe end and the second pipe end. In the optimal position, the first pipe end and the second pipe end are aligned to each other, such that the flexible tube can be mounted between them in an unloaded manner, without any forces acting on the flexible tube in any direction. In this way, the flexible tube will be mounted in a straight state between the first pipe end and the second pipe end. By mounting the flexible tube in a straight state, the side forces that will act on the flexible tube during use will be minimized, and the maximal deflection of the flexible tube will be minimized.
The alignment tool is semi-circular with a length that corresponds to the length of the flexible tube, which corresponds roughly to the distance between the first pipe end and the second pipe end. The body of the alignment tool may be rounded or substantially rounded. The diameter of the alignment tool corresponds to the diameter of the flexible tube. In this way, the alignment tool will bear on the flexible tube when it is attached to the flexible tube, and will hold the flexible tube in a straight state. The semi-circular shape will ensure that the flexible tube is supported in a horizontal, sideway direction. By attaching the alignment tool with an attachment means to the flexible tube, the alignment tool will also support the flexible tube in a vertical direction. The flexible tube is relatively stiff but still bendable. The flexible tube may e.g. be a double-braided exhaust pipe having rigid end flanges. The alignment tool will hold the flexible tube in a straight state during mounting of the flexible tube.
By holding the flexible tube in a straight state, the first pipe end and the second pipe end can be clamped in a position in which they are aligned to each other, such that the flexible tube will remain straight when the alignment tool is removed. This will ensure that the stress imposed on the flexible tube during use will be minimized, and that the deflection of the flexible tube is minimized during use. This will reduce the wear of the flexible tube, and will thus prolong the life of the flexible tube.
The alignment tool is attached to the flexible tube with an attachment means in a removable manner. The attachment means may be disposable or reusable. In one example, the alignment tool is attached to the flexible tube with a disposable cable tie. The cable tie is strong enough to hold the flexible tube in a straight state during the mounting process. The alignment tool may also be attached to the flexible tube with a reusable strap having e.g. a quick release buckle. The alignment tool may also be attached to the flexible tube with two or more attachment means.
The alignment tool is in one example provided with a handle that simplifies the handling of the alignment tool. The handle is provided with an opening through which the attachment means may be threaded. The alignment tool is in one example provided with protrusions or edges at the ends of the alignment tool, pointing inwards from the inner side. The protrusions or edges are adapted to correspond with the end regions of the flexible tube, which e.g. are stiff flanges. This will ensure that the alignment tool is positioned in the proper lengthwise position on the flexible tube.
In a method for mounting a flexible tube between a first pipe end and a second pipe end, the steps of; placing a flexible tube between the first pipe end and the second pipe end; attaching an alignment tool to the flexible tube with an attachment means in a removable manner, such that the flexible tube is held in a straight position; aligning the first pipe end to the second pipe end by adjusting the position of at least one pipe end, such that they are aligned to each other; clamping at least one pipe end in the aligned position; clamping the flexible tube to at least one pipe end; and removing the alignment tool from the flexible tube are comprised.
By this first embodiment of the method, the flexible tube can be mounted in an optimal position between the first pipe end and the second pipe end. In the optimal position, the first pipe end and the second pipe end are aligned to each other, such that the flexible tube can be mounted between them in an unloaded manner, without any force acting on the flexible tube in any direction. In this way, the flexible tube will be mounted in a straight state between the first pipe end and the second pipe end. By mounting the flexible tube in a straight state, the side forces that will act on the flexible tube during use will be minimized, and the maximal deflection of the flexible tube will be minimized.
The invention will be described in greater detail in the following, with reference to the attached drawings, in which
The embodiments of the invention with further developments described in the following are to be regarded only as examples and are in no way to limit the scope of the protection provided by the patent claims.
The body 2 of the alignment tool 1 is semi-circular such that it will enclose half of the flexible tube. In this way, the flexible tube can be securely held in a straight manner, and it is easy to attach the alignment tool to the flexible tube and to remove the alignment tool from the flexible tube. With a body that extends around the flexible tube by 180 degrees, the flexible tube is held securely in a sideway direction between the two side edges of the alignment tool. The surface of the body 2 of the alignment tool 1 may be closed or may comprise openings.
The alignment tool 1 is attached to the flexible tube 8 with an attachment means 11 in a removable manner.
The alignment tool is in the shown example provided with a handle 5 that simplifies the handling of the alignment tool. The handle is provided with an opening through which the attachment means can be threaded. When a reusable attachment means is used, the opening can be used to secure the attachment means to the alignment tool, such that it does not fall off. The alignment tool is in the shown example provided with protrusions or edges extending from the inner side 12 of the body, a first protrusion 6 at the first end 3 of the alignment tool and a second protrusion 7 at the second end 4 of the alignment tool. The protrusions are adapted to correspond with the end regions of the flexible tube, which e.g. are stiff flanges. This will ensure that the alignment tool is positioned in the proper lengthwise position on the flexible tube.
The flexible tube is in the example shown in
In the exhaust system, the exhaust manifold 15 is mounted to the engine in a fixed way. A first curved pipe 13 is mounted to the exhaust manifold 15 or a turbo mounted to the exhaust manifold, and the flexible tube is mounted to the first curved pipe 13. In one example, the first curved pipe is fixedly mounted to the exhaust manifold or turbo, e.g. by clamping or welding. The flexible tube is fixedly mounted to the first curved pipe, e.g. by clamping or welding.
In another example, the first curved pipe 13 is mounted to the exhaust manifold 15 or a turbo mounted to the exhaust manifold in an adjustable manner, and the flexible tube is mounted to the first curved pipe 13 in an adjustable manner. The first curved pipe can be rotated with respect to the exhaust manifold such that the position of the first pipe end can be set in a desired position and direction. When the desired position of the first pipe end is set, the first curved pipe is clamped to the exhaust manifold.
The second curved pipe 14 is mounted to the muffler 18 of the exhaust system in an adjustable manner. The second curved pipe can be rotated with respect to the muffler such that the position of the second pipe end can be set in a desired position and direction. When the desired position of the second pipe end is set, the second curved pipe is clamped to the muffler.
When the engine is mounted on the chassis, and the muffler is mounted on the chassis, at least one of the first curved pipe and the second curved pipe is adjustable. The purpose of this is to align the two pipe ends to each other, such that the pipe ends are aligned on the same central axis, i.e. that the pipe ends are parallel and concentric. By aligning the two pipe ends to each other, it is ensured that the flexible tube can be mounted between the two curved pipes in a straight and stress free manner. This will in turn ensure that the forces acting on the flexible tube are minimized and that the deflections of the flexible tube are minimized. This will prolong the life of the flexible tube.
In a normal production flow, the first curved pipe is mounted and clamped to the exhaust manifold or a turbo in one mounting cycle. The second curved pipe is mounted and clamped to the muffler of the exhaust system in another mounting cycle, and the muffler may be assembled at another mounting station before it is mounted to the chassis. The operator tries to position the first and the second curved pipe in a desired position as good as possible, e.g. by experience, but without an alignment guide, it is difficult to set the pipe ends in an exact position. Further, the desired position of the second pipe end of the second curved pipe is dependent on the position of the first pipe end of the first curved pipe. Thus, the end result is often that the two pipe ends are not aligned to each other. There may be an offset of several millimetres or more in any direction, sometimes more and sometimes less. The alignment tolerance for a given flexible tube may e.g. be 3 millimetres. This means that for some exhaust system installations, the flexible tube will be mounted between the two curved pipes in an oblique manner, in which there is a sideway load on the flexible tube when the vehicle is standing still and the engine is not running. When the vehicle starts moving, there will be an excessive load on the flexible tube in some directions, which will lead to increased wear and a reduced life for the flexible tube.
By using the alignment tool when mounting the flexible tube between the two curved pipes, this misalignment can be avoided. In this method, the first curved pipe is mounted to the exhaust manifold in one mounting cycle. The first curved pipe may be mounted to the exhaust manifold in a fixed or adjustable manner. The second curved pipe is mounted to the muffler of the exhaust system in another mounting cycle, and is mounted in an adjustable manner to the muffler. When the engine and the muffler are in place in the vehicle, the flexible tube is attached between the first curved pipe and the second curved pipe. The alignment tool is attached to the flexible tube in a removable manner with an attachment means, e.g. a cable tie or a strap. The flexible tube is now securely held in a straight state by the alignment tool, and will not deflect from the straight state during the clamping of the curved pipes. With the flexible tube in a straight state, the first curved pipe and thus the first pipe end can be aligned to a desired position and can then be clamped to the exhaust manifold, if it is not fixedly mounted in a predefined position. The second curved pipe and thus the second pipe end can be aligned to the first pipe end and can then be clamped to the muffler. With the two pipe ends aligned to each other, the flexible tube can be clamped to the first pipe end and to the second pipe end, or to the second pipe end if the flexible tube is fixedly attached to the first pipe end. The alignment toll may be removed from the flexible tube before or after the flexible tube has been clamped to the pipe ends.
The alignment tool is attached to the flexible tube with an attachment means in a removable manner. The attachment means may be disposable or reusable. In one example, the alignment tool is attached to the flexible tube with a disposable cable tie. The cable tie is strong enough to hold the flexible tube in a straight state during the mounting process. The alignment tool may also be attached to the flexible tube with a reusable strap having e.g. a quick release buckle. The alignment tool may also be attached to the flexible tube with two or more attachment means.
The alignment tool is in one example provided with a handle that simplifies the handling of the alignment tool. The handle may be provided with an opening through which the attachment means can be threaded. The alignment tool is in one example provided with protrusions or edges at the ends of the alignment tool, extending from the inner surface of the alignment tool. The protrusions are adapted to correspond with the end regions of the flexible tube, which e.g. are stiff flanges. This will ensure that the alignment tool is positioned in the proper lengthwise position on the flexible tube.
In step 100, the flexible tube is placed between the first pipe end and the second pipe end. The flexible tube is placed with its flanges extending over the pipe ends, either on the inside or on the outside of the pipe ends, such that the flexible tube is held in position between the two pipe ends. The flexible tube may be fixedly attached to one of the pipe ends.
In step 110, the alignment tool is attached to the flexible tube with an attachment means in a removable manner, such that the flexible tube is held in a straight state.
In step 120, the first pipe end is aligned to the second pipe end such that they are aligned to each other. Depending on the mounting process, either one or both of the pipe ends are adjusted in order to align the pipe ends to each other.
In step 130, the first pipe end, the second pipe end or both pipe ends are clamped in the aligned position, depending on how the curved pipes of the pipe ends are mounted.
In step 140, the flexible tube is clamped to one or both of the pipe ends.
In step 150, the alignment tool is removed from the flexible tube.
The invention is not to be regarded as being limited to the embodiments described above, a number of additional variants and modifications being possible within the scope of the subsequent patent claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21163312.8 | Mar 2021 | EP | regional |
