SYSTEM AND METHOD FOR JOINING DISSIMILAR MATERIALS
An assembly includes a first structural member made from a first material, such as aluminum, a second structural member made from a second material, such as magnesium, and adapted to mate and interlock with the first member, and a third structural member made from the first material to facilitate a permanent affixation between the first and second members. The second member fits within the first member and the third member fits within the second member. The second member includes at least one aperture surrounded by a protrusion, and the third member includes at least one aperture that mates and interlocks with the protrusion. A surface of the third member is exposed through the apertures of the first and second members. The first member is welded to the third member through the apertures in order to permanently affix the first and second members to one another without metallurgical altering or local welding of the second member.
This application is a Section 111(a) application relating to commonly owned, co-pending U.S. Provisional Application Ser. No. 61/062,268 entitled “SYSTEM AND METHOD FOR JOINING DISSIMILAR MATERIALS” filed Jan. 24, 2008.
FIELD OF THE INVENTIONThe present invention relates to a system and method for joining structural and mechanical parts made from dissimilar materials.
BACKGROUND OF THE INVENTIONTwo main issues with joining dissimilar materials are material compatibility and applicability of the joining process. More particularly, there are issues involved with joining aluminum to magnesium, to steel or to composites with known joining processes, such as fusion welding (e.g., gas metal arc welding) and solid-state welding (e.g., friction stir welding). These include metallurgical incompatibility, which results in uncontrolled cracking in welds and/or formation of brittle intermetallics; drastic differences in electromotive potential, which may lead to severe galvanic corrosion in the presence of salts and/or moisture; and incompatibility in the coefficient of thermal expansion, which could cause formation of intense residual stresses at joints and lead to failure under certain loading conditions, such as stress corrosion. What is needed is an appropriate system and method for proper joining of structural and mechanical parts made from dissimilar materials (e.g., metals and metal composites) to allow, among other things, the proper transmission of loads between them.
SUMMARY OF THE INVENTIONA structural assembly that includes a first structural member made from a first material, a second structural member made from a second material and adapted to mate and interlock with the first structural member, and a third structural member made from the first material to facilitate the permanent affixation between the first and second structural members. More particularly, the first structural member includes a post made from a first material, such as aluminum, the second structural member includes a tube made from a second material, such as magnesium, and is sized and shaped to fit within the post, and an insert made from the first material (e.g., aluminum) that is sized and shaped to fit within the tube. The post includes at least one aperture encircled by an inwardly extending protrusion, and the tube includes at least one aperture that is sized and shaped to mate and interlock with the protrusion when the post and tube are mated and interlocked with one another. When the post, tube and insert are mated and interlocked with one another, a snug fit is formed between the post and the tube and between the tube and the insert. In such configuration, an outer surface of the insert is exposed through the aperture of the post and the aperture of the tube. The aperture of the tube is substantially encased or shielded by the protrusion of the post such that there are no exposed surfaces of the tube in the area of the aperture of the post and the outer surface of the insert. Consequently, the aluminum post may be welded to the aluminum insert, thereby permanently affixing, for example, the aluminum post and the magnesium tube to one another without metallurgical altering or local welding of the magnesium tube.
Further features and advantages of the invention will appear more clearly on a reading of the detailed description of the embodiments of the invention, which is given below by way of example only with reference to the accompanying drawings.
For a better understanding of the present invention, reference is made to the following detailed description of the embodiments considered in conjunction with the accompanying drawings, in which:
Referring to
With continued reference to
Still referring to
Still referring to
Next, the tube 14 and the insert 16 assembly as described above are slidably inserted into the cavity 30 of the post 12 at an end 20 thereof. The cavity 30 of the post 12 is sized and shaped such that the tube 14 and the insert 16 elastically deflect inwardly when the tube 14 and the insert 16 are inserted into the post 12 (see
It is also noted that the apertures 32, 34 of the post 12 are not aligned with one another along axis A-A, as shown in
As the tube 14 and the insert 16 assembly continues to be inserted within the post 12, the protrusions 42, 46 act against the wall 52 of the tube 14 to maintain the deflection of the tube 14 and the insert 16 as discussed above. Once again, the curved surfaces 101, 103 of the tabs 100, 102 and the “tea-cup” shapes of the protrusions 42, 46 enable the tabs 100, 102 to slide over the protrusions 44, 48, respectively.
The welds 102, 104 may be made from any welding process known in the art, such as fusion-based (e.g., GMAW, GTAW, LBW, LSBW, etc.) or solid-state based (e.g., FSW, FW Plunge, etc.). Alternatively, the welds 102, 104 need not be included, and the welding process described above could be substituted with any other joining and fixation processes known in the art, such as rivets, bolts, screws, etc. that enable the post 12 and tube 14 to be secured together in a manner that ensures the mechanical interlocks between them do not separate.
The mechanical interlocking features of the post and joint assembly 10 enable load transmission through the post 12 and the tube 14, while simultaneously keeping the subsequent joining operations localized and confined to joining the post 12 and the insert 16 (which are made of the same material) and separate from the tube 14.
Another embodiment of the present invention is illustrated in
Another embodiment of the present invention is illustrated in
Another embodiment of the present invention is illustrated in
Referring to
The method includes lock-joining together parts made from dissimilar materials through the use of interlocking means on the parts at the joints betwee n them, and the use of another (i.e., secondary) joining process whose application is separate from and confined to joining two parts made from the same material, which ensures that the mechanical interlocks between the parts of dissimilar materials do not become separated.
The term “snug fit” is defined as a gap or space (or a lack thereof between each of the protrusions 40, 42, 44, 46 of the post 12 and the outer surface of the insert 16 being in the range of zero up to a dimension that does not expose a surface of the tube 14 to the welding process. The term “mate” is defined as to join, fit, associate, assemble or couple parts or components with one another. The term “interlock” means to lock, fasten or fix parts or components with one another to ensure a stable and desirable coordinately functioning structure or action.
It should be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and scope of the invention. Accordingly, all such variations and modifications are intended to be included within the scope of the embodiments described herein as defined in the appended claims.
Claims
1. An assembly, comprising:
- a first structural member made from a first material and having at least one locking member;
- a second structural member made from a second material and having at least one retention structure, the at least one locking member of the first structural member is sized and shaped to mate with the at least one retention structure of the second structural member so as to interlock the first and second structural members with one another;
- a third structural member made from the first material and mated with the first and second structural members, the first structural member and the third structural member being joined directly to one another so as to facilitate a permanent connection between the first and second structural members.
2. The assembly of claim 1, wherein the first structural member includes a first surface and a second surface opposite the first surface, and wherein the at least one locking member of the first structural member includes at least one protrusion extending from the second surface, and wherein the second structural member includes a first surface and a second surface opposite the first surface of the second structural member, the at least one retention structure of the second structural member includes an aperture extending from the first surface of the second structural member to the second surface of the second structural member.
3. The assembly of claim 2, wherein the first structural member includes at least one aperture that extends from the first surface of the first structural member to the second surface of the first structural member, the at least one protrusion surrounds the at least one aperture of the first structural member, the at least one aperture of the first structural member and the at least one aperture of the second structural member being aligned substantially with one another.
4. The assembly of claim 3, wherein the third structural member includes a first surface, the first, second and third structural members being positioned relative to one another such that the first surface of the third structural member is exposed through the at least one aperture of the first structural member and the at least one aperture of the second structural member.
5. The assembly of claim 4, wherein the at least one protrusion of the first structural member includes a plurality of protrusions, and the at least one aperture of the second structural member includes a plurality of apertures, one of the plurality of protrusions of the first structural member being sized and shaped to mate with a corresponding one of the plurality of apertures of the second structural member.
6. The assembly of claim 5, wherein the at least one aperture of the first structural member includes a plurality of apertures, one of the plurality of protrusions of the first structural member surrounds a corresponding one of the plurality of apertures of the first structural member, and one of the plurality of apertures of the first structural member and a corresponding one of the plurality of apertures of the second structural member being aligned substantially with one another.
7. The assembly of claim 6, wherein each of the plurality of protrusions of the first structural member is welded to the first surface of the third structural member.
8. The assembly of claim 7, wherein each of the plurality of apertures of the first structural member is circular in shape, and each of the plurality of apertures of the second structural members is circular in shape.
9. The assembly of claim 7, wherein the first material is aluminum.
10. The assembly of claim 8, wherein the second material is magnesium.
11. The assembly of claim 8, wherein the second material is steel.
12. The assembly of claim 8, wherein the second material is an organic based composite.
13. The assembly of claim 8, wherein the second material is an inorganic based composite.
14. An assembly, comprising:
- a first structural member made from a first material and having a first end, a second end opposite the first end, and a cavity extending from the first end to the second end;
- a second structural member made from a second material and having a first end, a second end opposite the first end of the second structural member, and a cavity extending from the first end of the second structural member to the second end of the second structural member; and
- a third structural member made from the first material and having a first end and a second end opposite thereof,
- the cavity of the second structural member is sized and shaped to receive slidably the third structural member at the first end of the second structural member, the cavity of the first structural member is sized and shaped to receive slidably the second and third structural members at the second end of the first structural member, the first structural member and the third structural member being joined directly to one another so as to facilitate a permanent connection between the first and second structural members.
15. The assembly of claim 14, wherein the first structural member includes a first wall having a first surface, a second surface opposite the first surface, and at least one protrusion extending from the second surface, the second structural member includes a first wall having a first surface, a second surface opposite the first surface of the first wall of the second structural member, and at least one aperture extending from the first surface of the first wall of the second structural member to the second surface of the first wall of the second structural member, the at least one protrusion is sized and shaped to mate with the at least one aperture so as to interlock the first and second structural members with one another.
16. The assembly of claim 15, wherein the first structural member includes at least one aperture that extends from the first surface of the first wall of the first structural member to the second surface of the first wall of the first structural member, the at least one protrusion surrounds the at least one aperture of the first structural member, and the at least one aperture of the first structural member and the at least one aperture of the second structural member being aligned substantially with one another.
17. The assembly of claim 16, wherein the third structural member includes a first wall having a first surface and a second surface opposite the first surface of the third structural member, the first, second and third structural members being positioned relative to one another such that the first surface of the first wall of the third structural member is exposed through the at least one aperture of the first structural member and the at least one aperture of the second structural member.
18. The assembly of claim 17, wherein the at least one protrusion of the first structural member is welded to the first surface of the first wall of the third structural member.
19. The assembly of claim 18, wherein the at least one protrusion of the first structural member includes a plurality of protrusions, and the at least one aperture of the second structural member includes a plurality of apertures, one of the plurality of protrusions of the first structural member being sized and shaped to mate with a corresponding one of the plurality of apertures of the second structural member.
20. The assembly of claim 19, wherein the at least one aperture of the first structural member includes a plurality of apertures, one of the plurality of protrusions of the first structural member surrounds a corresponding one of the plurality of apertures of the first structural member, and one of the plurality of apertures of the first structural member and a corresponding one of the plurality of apertures of the second structural member being aligned substantially with one another.
21. The assembly of claim 20, wherein the first structural member includes a second wall having a first surface, a second surface opposite the first surface of the second wall, and at least one protrusion extending from the second surface of the second wall, the second structural member includes a second wall having a first surface, a second surface opposite the first surface of the second wall of the second structural member, and at least one aperture extending from the first surface of the second wall of the second structural member to the second surface of the second wall of the second structural member, the at least one protrusion of the second wall of the first structural member is sized and shaped to mate with the at least one aperture of the second wall of the second structural member so as to interlock the first and second structural members with one another.
22. The assembly of claim 21, wherein the first structural member includes at least one aperture that extends from the first surface of the second wall of the first structural member to the second surface of the second wall of the first structural member, the at least one protrusion of the second wall of the first structural member surrounds the at least one aperture of the second wall of the first structural member, and the at least one aperture of the second wall of the first structural member and the at least one aperture of the second wall of the second structural member being aligned substantially with one another.
23. The assembly of claim 22, wherein the third structural member includes a second wall having a first surface and a second surface opposite the first surface of the second wall of the third structural member, the first, second and third structural members being positioned relative to one another such that the first surface of the second wall of the third structural member is exposed through the at least one aperture of the second wall of the first structural member and the at least one aperture of the second wall of the second structural member.
24. The assembly of claim 23, wherein the at least one protrusion of the first structural member is welded to the first surface of the second wall of the third structural member.
25. The assembly of claim 24, wherein the at least one protrusion of the second wall of the first structural member includes a plurality of protrusions, and the at least one aperture of the second wall of the second structural member includes a plurality of apertures, one of the plurality of protrusions of the second wall of the first structural member being sized and shaped to mate with a corresponding one of the plurality of apertures of the second wall of the second structural member.
26. The assembly of claim 25, wherein the at least one aperture of the second wall of the first structural member includes a plurality of apertures, one of the plurality of protrusions of the second wall of the first structural member surrounds a corresponding one of the plurality of apertures of the second wall of the first structural member, and one of the plurality of apertures of the second wall of the first structural member and a corresponding one of the plurality of apertures of the second wall of the second structural member being aligned substantially with one another.
27. The assembly of claim 26, wherein the third structural member includes a cavity extending from the first end of the third structural member to the second end of the third structural member, and wherein the second structural member includes a pair of slots formed within the first wall of the second structural member and each extending from the first end of the second structural member to a point distal from the first end of the second structural member, and the third structural member includes a pair of slots formed within the first wall of the third structural member and each extending from the first end of the third structural member to a point distal from the first end of the third structural member,
- each of the pair of slots of the second structural member being sized and shaped to enable the first wall of the second structural member to move between an undeflected position to a deflected position, the first wall of the second structural member is urged from the undeflected position toward the deflected position when the second structural member is partially inserted within the cavity of the first structural member, and the first wall of the second structural member returns from the deflected position to substantially its the undeflected position when the second structural member is fully inserted within the cavity of the first structural member, and
- each of the pair of slots of the third structural member being sized and shaped to enable the first wall of the third structural member to move between an undeflected position to a deflected position, the first wall of the third structural member is urged from its the undeflected position toward its the deflected position when the second structural member is partially inserted within the cavity of the first structural member, and the first wall of the third structural member returns from its the deflected position to substantially its the undeflected position when the second structural member is fully inserted within the cavity of the first structural member.
28. The assembly of claim 27, wherein the second structural member includes a second pair of slots formed within the second wall of the second structural member and each extending from the first end of the second structural member to a point distal from the first end of the second structural member, and the third structural member includes a second pair of slots formed within the second wall of the third structural member and each extending from the first end of the third structural member to a point distal from the first end of the third structural member,
- each of the second pair of slots of the second structural member being sized and shaped to enable the second wall of the second structural member to move between an undeflected position to a deflected position, the second wall of the second structural member is urged from its the undeflected position toward its the deflected position when the second structural member is partially inserted within the cavity of the first structural member, and the second wall of the second structural member returns from its the deflected position to substantially its the undeflected position when the second structural member is fully inserted within the cavity of the first structural member, and
- each of the second pair of slots of the third structural member being sized and shaped to enable the second wall of the third structural member to move between an undeflected position to a deflected position, the second wall of the third structural member is urged from its the undeflected position toward its the deflected position when the second structural member is partially inserted within the cavity of the first structural member, and the second wall of the third structural member returns from its the deflected position to substantially its the undeflected position when the second structural member is fully inserted within the cavity of the first structural member.
29. The assembly of claim 28, wherein each of the first, second and third structural members is generally rectangular in cross section.
30. The assembly of claim 28, wherein the first material is aluminum.
31. The assembly of claim 30, wherein the second material is magnesium.
32. The assembly of claim 30, wherein the second material is steel.
33. The assembly of claim 30, wherein the second material is an organic based composite.
34. The assembly of claim 30, wherein the second material is an inorganic based composite.
35. A method, comprising the steps of:
- providing a first structural member made from a first material and having at least one locking member;
- connecting a second structural member, made from a second material and having at least one retention structure, to the first structural member, the at least one locking member of the first structural member is sized and shaped to mate with the at least one retention structure of the second structural member so as to interlock the first and second structural members when the are connected to one another;
- providing a third structural member, made from the first material, and mating it with the first and second structural members; and
- joining directly the first structural member and the third structural member with one another so as to facilitate a permanent connection between the first and second structural members.
Type: Application
Filed: Aug 19, 2008
Publication Date: Jul 30, 2009
Inventors: Israel Stol (Pittsburgh, PA), Trent Chontas (Braddock Hills, PA)
Application Number: 12/193,958
International Classification: E04B 2/32 (20060101);