TAIL PIPE MOUNTING ARRANGEMENT

Abstract

An exhaust tailpipe mounting system for mounting on an exhaust pipe end includes a tailpipe and a ring member attached to the tailpipe. At least three spring elements are attached to the ring member, wherein each spring element extends generally along a longitudinal axis and is bent into a wave shape. Each spring element has a proximal end opposite a distal end, where the proximal end is attached to the ring member and the distal end has at least one pointed end configured to grip into an outer surface of the exhaust pipe end. Each spring element has a first, second, third, fourth, fifth, sixth and seventh bend zone starting from the proximal end and respectively going to the distal end. The at least one pointed end of is angled at an angle of 75 to 85 in relation to the longitudinal axis of the spring elements.

Claims

1. An exhaust tailpipe mounting system for mounting of a tailpipe on an exhaust pipe end, said exhaust tailpipe mounting system comprising: a spring arrangement of at least three spring elements which are attachable to the tailpipe, wherein each spring element extends generally along a longitudinal axis and is bent into a wave shape and comprises a first end having a connection end part configured for connection to an inner surface of the tailpipe and a second end forming a distal end gripping part, the distal end gripping part comprising at least one cut-out forming at least two pointy ends, where the pointy ends of the distal end gripping part are configured to grip into an outer surface of the exhaust pipe end; wherein the wave shape of each of the at least three spring elements comprises: a first bend zone between the connecting end part and a first downward wave part, where the first downward wave part comprises a second bend zone and a third bend zone, where the second bend zone has a bending radius of 2.5 mm to 5.5 mm and the third bend zone has a bending radius of 2.0 mm to 3.0 mm; a first upward wave part having a fourth bend zone; a second downward wave part having a fifth bend zone and a sixth bend zones, where the fifth bending radius is at least 8.0 mm and where the sixth bend zone has a bending radius of 2.0 mm to 3.0 mm; wherein the second downward wave part is followed by a second upwards wave part having a seventh bend zone, wherein the second upwards wave part connects the second downward wave part and the distal end gripping part, wherein an upwardly extending spring part is defined between the sixth and the seventh bend zones; wherein the seventh bend zone connects the distal end gripping part to the upwardly extending spring part at an angle of 35 to 45; and wherein the distal end gripping part is angled at an angle of 75 to 85 in relation to the longitudinal axis of the spring elements.

2. The exhaust tailpipe mounting system according to claim 1, wherein the at least three spring elements are attached to a ring member having an outer diameter corresponding to an inner diameter of the tailpipe.

3. The exhaust tailpipe mounting system according to claim 2, wherein the at least three spring elements comprise at least four spring elements.

4. The exhaust tailpipe mounting system according to claim 2, wherein the at least three spring elements comprise at least five spring elements.

5. The exhaust tailpipe mounting system according to claim 2, wherein the at least three spring elements comprise at least seven spring elements.

6. The exhaust tailpipe mounting system according to claim 1, wherein each of the spring elements have an arc shaped cross section when seen in a cross section perpendicularly to the longitudinal axis of each spring element, and where the arc shape of an upper surface of each spring element corresponds to the inner surface of the tail pipe.

7. The exhaust tailpipe mounting system according to claim 1, wherein the first bending zone has a bending radius of 1.0 mm to 2.0 mm.

8. The exhaust tailpipe mounting system according to claim 1, wherein the fourth and the seventh bending zones each have a bending radius of 1.0 mm to 4.5 mm.

9. The exhaust tailpipe mounting system according to claim 1, wherein the fourth and the seventh bending zones each have a bending radius of 1.5 mm to 3.5 mm.

10. The exhaust tailpipe mounting system according to claim 1, wherein the first bending zone is bent in an angle of 125 to 145, the third bending zone is bent in an angle of 110 to 130, the fourth bending zone is bent in an angle of 55 to 75, and/or the sixth bending zone is bent in an angle of 110 to 130.

11. An exhaust tailpipe mounting system for mounting on an exhaust pipe end, said exhaust tailpipe mounting system comprising: a tailpipe, a ring member attached to the tailpipe, the ring member having an outer diameter corresponding to an inner diameter of the tailpipe; at least three spring elements attached to the ring member, wherein each spring element extends generally along a longitudinal axis and is bent into a wave shape, wherein each spring element comprises a proximal end opposite a distal end, where the proximal end is attached to the ring member and the distal end has at least one pointed end, where the at least one pointed ends is configured to grip into an outer surface of the exhaust pipe end; wherein each spring element has a first, second, third, fourth, fifth, sixth and seventh bend zone starting from the proximal end and respectively going to the distal end, wherein the first, fourth and seventh bends zones are bent in an opposite direction in comparison to the second, third, fifth and sixth bend zones; wherein the second bend zone has a bending radius of 2.5 mm to 5.5 mm; wherein the third bend zone has a bending radius of 2.0 mm to 3.0 mm; wherein the fifth bend zone has a bending radius at least 8.0 mm; wherein the sixth bend zone has a bending radius of 2.0 mm to 3.0 mm; wherein an upwardly extending spring part is defined between the sixth and the seventh bend zones; wherein the seventh bend zone connects the at least one pointed end of the distal end to the upwardly extending spring part at an angle of 35 to 45; and wherein the at least one pointed end of the distal end is angled at an angle of 75 to 85 in relation to the longitudinal axis of the spring elements.

12. The exhaust tailpipe mounting system according to claim 11, wherein the first bend zone has a bending radius of 1.0 mm to 2.0 mm.

13. The exhaust tailpipe mounting system according to claim 12, wherein the fourth and the seventh bend zones each have a bending radius of 1.0 mm to 4.5 mm.

14. The exhaust tailpipe mounting system according to claim 12, wherein the fourth and the seventh bend zones each have a bending radius of 1.5 mm to 3.5 mm.

15. The exhaust tailpipe mounting system according to claim 11, wherein the first bend zone is bent in an angle of 125 to 145, the third bend zone is bent in an angle of 110 to 130, the fourth bend zone is bent in an angle of 55 to 75, and/or the sixth bend zone is bent in an angle of 110 to 130.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The present invention will described in detail with reference to the drawings in which:

[0062] FIG. 1 shows a perspective view of a spring of a tail pipe mounting arrangement according to the present invention;

[0063] FIG. 2 shows a cross sectional view through A-A of FIG. 4 of a tail pipe mounted on an exhaust pipe using the spring based mounting arrangement according to the invention;

[0064] FIG. 3 shows an exploded view of an embodiment of the tail pipe mounting system

[0065] FIG. 4 shows a cross sectional view through B-B of FIG. 2 of a tail pipe mounted on an exhaust pipe using the spring based mounting arrangement according to the invention;

[0066] FIGS. 5 and 6 show a side view of a spring element used in a tailpipe mounting system according to the invention;

[0067] FIG. 7 shows a detail of the spring in cross sectional view of a tail pipe mounted on an exhaust pipe using the spring based mounting arrangement according to the invention; and

[0068] FIGS. 8 and 9 show graphs of the assembly force and the pulling force as a function of the distance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069] The exhaust tailpipe mounting system for mounting of a tailpipe 1 on an exhaust pipe 2 end comprises a spring arrangement of at least three spring elements 3, preferably at least four, such as five or seven springs 3 which are to be attached to the tailpipe 1.

[0070] The springs are attached at their connection end part 9 to the inner surface 10 of the tail pipe 1, e.g. by welding, brazing or the like permanent attachment means (not shown). The springs 3 are mounted with the barbs 13 towards the outer end 26 of the tail pipe and the connecting part 9 towards the end from which the tail pipe 1 is mounted on the exhaust pipe 2.

[0071] Alternatively the at least three, preferably at least four, in particular five or seven springs 3 are attached to a ring member 4 as shown in FIGS. 2-4. The ring member has an outer diameter corresponding to the inner diameter of the tailpipe 1. The ring member is arranged in the tailpipe 1 and fastened to the tail pipe 1 by means of a mounting flange 7 which retains the spring arrangement in position in the tail pipe 1. The mounting flange 7 is then attached to the tail pipe by means of e.g. one or more screws or bolts 5 and nuts 6 or studs or rivets through one or more holes 8 in the tail pipe 1.

[0072] When the springs 3 are attached to the tail pipe 3 the tail pipe 3 is simply pushed onto the end of the exhaust pipe 2 for mounting of the tail pipe. Thus, during mounting of the tailpipe 1, the first downwardly extending wave part 16 of the spring engages the exhaust pipe at first, resulting in an initial assembly force needed for assembly. Then the second downwardly extending wave part 21 and finally the barbs 13 at the distal end engages the exhaust pipe's 2 outer surface 14 resulting in an intermediate increase in the assembly force and the final assembly force.

[0073] The springs 3 are thus arranged between the tailpipe 1 and the exhaust pipe 2 when mounted. The upwardly extending wave parts 19, 24 rest against the inner surface of the tail pipe while the horizontal spring part of the downwardly extending wave parts 16, 21 rest against the outer surface 14 of the exhaust pipe 2 and provides a frictional grip against the outer surface of the exhaust pipe.

[0074] The spring design is seen in FIGS. 1 and 5-6.

[0075] Each spring element is bent into a wave shape having a generally W-like shape between a first end having a connection end part 9 intended for connection to an inner surface of a tailpipe, and a second, i.e. a distal end, end forming a distal end gripping part 11.

[0076] The spring element 3 may have an arc shaped cross section, when seen in a cross section perpendicularly to the longitudinal axis of the spring element 3. The arc shape of the upper surface of the spring 3 corresponds to the diameter of the inner surface of the tail pipe 1.

[0077] The distal end gripping part 11 comprises at least one cut-out 12 at the distal end of the spring for forming at least one and preferably two pointy ends 13, which act as barbs 13 intended for digging into an outer surface 14 of the exhaust pipe 2.

[0078] The W-like shape between the first end and the second ends of the spring 3 is provided by bending a rectangular spring steel member at a number of bend zones. The bends zones are provided perpendicularly or substantially perpendicularly to the longitudinal axis of the spring element 3.

[0079] The bend zones will be described in order from the connection end part 9 towards the distal end gripping part 11.

[0080] The first bend zone 15 connects the connecting end part 9 and a first downward wave part 16. The first bending zone 15 may have a bending radius (at the lower side of the spring) of 1.0 mm to 2.0 mm, and preferably 1.4 mm to 1.6 mm. A bending radius which is as small as possible at the first bend zone 15 will provide stiffness to the spring in the area.

[0081] The first downward wave part 16 comprises a second 17 and a third 18 bend zone resulting in a downward inclined spring part, a horizontal spring part and an upwardly inclined spring part.

[0082] The second bend zone 17 has a bending radius (at the lower side of the spring) of 2.5 mm to 5.5 mm, preferably 4.5 mm to 5.5 mm. The second bend zone 17 is the first part of the spring which contacts the outer surface 14 of the exhaust pipe when mounting the tail pipe. The contact resulting in an initial assembly force of approximately 100-200 N needed for sliding the lower surface of the first downward wave part 16 over outer surface 14 of the exhaust pipe 1. An increase in the bending radius at the second bend zone 17 decreases the initial assembly force needed for pushing the tail pipe with the springs attached to the inner surface onto the exhaust pipe.

[0083] The third bend zone 18 has a bending radius (at the upper side of the spring) of 2.0 mm to 3.0 mm, and preferably 2.4 mm to 2.6 mm in order to maintain shape and stiffness of the spring.

[0084] The first downward wave part 16 is followed by a first upward wave part 19 having a fourth bend zone 20 which connects the inclined spring parts of the first 16 and the second 21 downwardly extending wave parts of the spring.

[0085] The first upwardly extending wave part 19 of the spring is intended for resting against the inner surface 10 of the tail pipe 1. The fourth bending zone 20 has a bending radius (at the upper side of the spring) of 1.0 mm to 4.5 mm, or preferably 1.5 mm to 3.5 mm.

[0086] The second downward wave part 21 has a fifth bend zone 22 and a sixth bend zone 23 resulting in a downward inclined spring part, a horizontal spring part and an upwardly inclined spring part 26 which provides the second downwardly extending wave shape. The bending radius (at the upper side of the spring) at the fifth bend zone 22 is at least 8.0 mm, preferably 8.0 mm to 15 mm, or more preferred 10.5 mm to 12.5 mm. Hereby the assembly force in the second step is approximately 100-200 N. The second downwardly extending wave part 21 is intended for resting against the outer surface 14 of the exhaust pipe 2 and align the tail pipe 1 on the exhaust pipe 2. The size of the radius at the fifth bend zone 22 is important for reducing the stepwise intermediate increase in the assembly force when the horizontal part of the second downwardly extending wave part of the springs is passed into contact with the outer surface of the exhaust pipe as explained above.

[0087] The fifth bend zone 22 is the first part of second downward wave part of the spring which contacts the outer surface of the exhaust pipe when mounting the tail pipe resulting in an intermediate increase of the assembly force needed for sliding the lower surface of the second downward wave part over the outer surface of the exhaust pipe.

[0088] The sixth bend zone 23 preferably has a bending radius (at the lower side of the spring) of 2.0 mm to 3.0 mm, and preferably 2.4 mm to 2.6 mm in order to maintain shape and stiffness of the spring and thus also sufficient tension to the spring to allow proper alignment of the tail pipe 1 in relation to the exhaust pipe 2 when mounted thereon.

[0089] The second downward wave part 21 is followed by a second upwards wave part 24 with a seventh bend zone 25, which connects the second downward wave part 21 and the distal end gripping part 11. The second upwardly extending wave part 24 is also intended for resting against the inner surface 10 of the tail pipe 1.

[0090] Preferably, the seventh bending zone 25 has a bending radius (at the upper side of the spring) of 1.0 mm to 4.5 mm, or preferably 1.5 mm to 3.5 mm.

[0091] The seventh bend zone 25 connects the distal end gripping part 11 to an upwardly extending spring part 26 between the sixth 23 and the seventh 25 bend zone at an angle a of 35 to 45.

[0092] The distal end gripping part 11 is angled at an angle b of 75 to 85 in relation to the longitudinal axis of the spring.

[0093] The second downwardly extending wave part 21 and the and outermost second upwardly extending wave part 24 build up the force acting on the barbs 13 at the gripping part 11 and thus assists in increasing the barbs grip force into the exhaust pipe's outer surface 14.

[0094] In addition, the barbs 13 influence the assembly force needed for sliding the barbs 13 against the surface meet the surface of the exhaust pipe, whereby the assembly force needed for pushing the tailpipe 1 onto the exhaust pipe 3 in a third step of up to 200-350 N.

[0095] The angle b at which the distal end gripping part 11, i.e. the barbs 13, meets the outer surface 14 of the exhaust pipe 2 is important for the force needed for pulling off the tail pipe. A high force for pulling off the tailpipe is required for eliminating any unintentional loss of the tail pipe during normal use of the vehicle. The initial pulling force required is at least 250 N on an exhaust pipe.

[0096] In addition, the angle b of the barbs 13 against the outer surface 14 of the exhaust pipe influence the assembly force needed for sliding the barbs 13 against the outer surface of the exhaust pipe.

[0097] Thus the angle a at the seventh bend zone 25, i.e. between lower surfaces on the spring parts at the distal end gripping part 11 and an upwardly extending spring part 26 between the sixth 23 and the seventh 25 bend zone, is 35 to 45 before mounting the tail pipe on the exhaust pipe. This provides relatively low assembly force.

[0098] This initially provided angle a is increased up to 45-90 as illustrated on FIG. 7, see angle a when the tail pipe 1 is mounted onto the exhaust pipe 2 caused by the tension from the spring resulting from the spring 3 being squeezed between the outer surface of the exhaust pipe 2 and the inner surface 10 of the tail pipe 1 when the tail pipe is mounted on the exhaust pipe. This results in deformation of the seventh bend zone 25 and reduces the angle a to a between the barbs 13 and the outer surface of the exhaust pipe, whereby the barbs 13 increases their effect and decreases the pulling force needed.

[0099] The second upward wave part of the spring is preferably provided at a height which is approximately 0.4-0.5 mm lower than the level of first upward wave part and the connection end part. This provides a slip, which reduces the assembly force when the barbs are pushed across the outer surface of the exhaust pipe during mounting. The tension provided on the spring when it is squeezed between the tail pipe and the exhaust pipe causes an upward movement of the upwardly inclined surface 26 which eliminates the slip and provides contact between the inner surface of the tail pipe and the upper surface on the second upward wave part. This causes a further tension on the barbs 13 which further increases the pull force needed for pulling off the tail pipe 1.

[0100] Preferably the angle c at the lower surface at the first bending zone is bent in an angle of 125 to 145 and preferably 130 to 140 in relation to the longitudinal axis of the spring.

[0101] Preferably, the third bending zone 18 is bent to provide an angle d of 110 to 130 and preferably 115 to 125 on the upper surface of the spring in relation to the longitudinal axis of the spring.

[0102] Preferably, the fourth bending zone 20 is bent in an angle e of 55 to 75 and preferably 60 to 70 at the lower surface of the spring.

[0103] Preferably, the sixth bending zone 22 is bent in an angle f at the upper surface of the spring of 110 to 130 and preferably 115 to 125 in relation to the longitudinal axis of the spring.

[0104] These the angles are selected from experience and should not vary more than 5 to 10 degrees. If the angle is large there is a risk of losing stability of the shape of the spring, whereas if the angle is small, the assembly force can increase.

[0105] The angles mentioned above also depended of the size of the bending radius on the relevant position of the relevant bending zone of the spring.

[0106] If the tailpipe is pulled off, the springs 3, or at least the gripping part 11 thereof will be deformed due to the pulling force needed.

Example

[0107] The assembly force and the pulling force was tested on springs of two different designs. Spring 1 is designed according to the present invention, whereas spring 2 is a comparative example.

[0108] Five springs were welded to the inner circumference of a tail pipe at equal distance as described above.

[0109] Spring 1 is made of stainless steel which is bent into shape as shown in FIGS. 1 and 5-6. Spring 2 of the comparative example is of same length and width and differs from spring 1 in the bend radius's of the bending zones as well as the angle a of the hook like end part. The bend radius of each bend zone and the angle appears in Table 1 below.

[0110] Spring material is a strip of 67.5 mm length and 9 mm width. The barbs are made by providing a cutout of a triangular shape and a 90 angle in the distal end of the spring strip. Spring steel material is austenitic stainless steel alloy X10CrNi 18-8 no 1.4310 as defined in the material norm EN 10088-2:2005. The spring tensile strength is 1000-1700 N/mm2 corresponding to grade +C1000 to +C1500 as defined in EN 10151:2002.

TABLE-US-00001 TABLE 1 Shape of spring 1 and 2 Spring 1, radius on upper side of spring (L = lower side; Spring 2 radius Angle or U = upper side bend on upper side of Bend zone radius); angle spring; angle Bend zone 1 2.0 mm (L) 2.0 mm (L) Bend zone 2 5.0 mm (L) 2.0 mm (L) Bend zone 3 2.5 mm (U) 2.0 mm (U) Bend zone 4 2.0 mm (U) 2.0 mm (U) Bend zone 5 11.7 mm (U) 2.0 mm (U) Bend zone 6 2.5 mm (L) 2.0 mm (L) Bend zone 7 2.76 mm (U) 2.0 mm (U) Angle a 40 55

[0111] An exhaust test pipe of stainless steel X5CrNi 18-10, no 1.4301, as defined in the material norm EN 10088-2:2005 was mounted vertically in a test bench using fixture. The tail pipe was mounted in a first fixture on the lower side of a vertical piston. The assembly force was measured by the piston applying a pushing a force to the tail pipe from above while detecting the assembly force (i.e. push force; in N as a function of the distance) used for pushing the tail pipe into position on the exhaust pipe. After completion of the mounting of the tailpipe a second test fixture was mounted on the tailpipe. The second test fixture engages the lower end of the tail pipe while raising the piston for providing a pulling force in the tail pipe while detecting the pull force (in N as a function of the distance). Five runs with tail pipes with spring 1 and five runs with spring 2 were carried out and the average values were calculated for the initial assembly force (first downward wave in contact with exhaust tube); intermediate assembly force (second downward wave in contact with exhaust tube) and final assembly force (barbs in contact with exhaust tube) and the averaged pull force was calculated for each run. The overall average of the pulling force on the five runs was then calculated. The averaged values appear in Table 2.

TABLE-US-00002 TABLE 2 Average assembly force/pulling force in N Position Spring 1 (N) Spring 2 (N) First downward wave (*1) 153 340 Second downward wave (*2) 156 490 Barbs (*3) 271 410 Pulling force, Average (*4) 544 557

[0112] FIG. 8 shows the assembly force as a function of the distance of the first run with spring 1 and 2 respectively. *1 illustrates the initial assembly force used when the first downward wave part of the springs come into contact with the exhaust pipe. *2 illustrates the intermediate assembly force used when the second downward wave part come into contact with the exhaust pipe. *3 illustrate the initial assembly force used when the barbs of the springs come into contact with the exhaust pipe. *5 illustrate the maximal pulling force used when pulling the tail pipe off the exhaust pipe.

[0113] It is clear from Table 2 and FIGS. 8 and 9 that spring 1 design requires a lower assembly force while maintaining a high pulling force.