Shape-memory saddle structure, particularly for pedal driven vehicles, and process for making such structure
A shape-memory saddle structure, particularly for pedal driven vehicles, comprising a substantially rigid or semirigid support frame ( 2 ), means ( 4 ) for connecting said frame ( 2 ) to a vehicle, a yielding pad ( 7 ) secured to the upper face (S) of the frame ( 2 ), and a cover layer ( 5 ) laid over the yielding pad ( 3 ). The frame ( 2 ) has one or more portions ( 6, 6′, 6 ″) having a different deformability from that of the rest of the frame ( 2 ). The portions ( 6, 6′, 6 ″) include at least one membrane of fibrous material, which is susceptible to permanent deformation in response to a compression stress by a user, so as to take a deformed configuration. The membrane ( 7 ) is closely joined to at least one layer of elastomeric material ( 8 ), which is adapted to locally change the rigidity of the membrane ( 7 ) by elastically holding it at least partly in the deformed configuration, to customize the frame ( 2 ) to the specific user's body.
1. A shape-memory saddle, comprising:
a support frame having an upper face, and one or more deformable portions defining areas of the support frame configured to be more susceptible to deformation than the rest of the support frame, said deformable portions comprising
at least one membrane of fibrous material; and
at least one layer of elastomeric material joined to the membrane, wherein said membrane has a predetermined starting configuration, said fibrous material of the membrane being deformable in response to a user-exerted force to take a final deformed configuration, and said elastomeric material is adapted to elastically hold said membrane in said deformed configuration to provide shape-memory properties.
2. Structure as claimed in claim 1 , wherein said at least one membrane of fibrous material is joined to said at least one layer of elastomeric material by a layer of resin.
3. Structure as claimed in claim 2 , wherein said resin is an epoxy resin.
4. Structure as claimed in claim 2 , wherein said resin is a thermosetting resin.
5. Structure as claimed in claim 4 , wherein said at least one layer of elastomeric material comprises a thermoplastic material.
6. Structure as claimed in claim 5 , wherein the softening point of said thermoplastic material is close to or above the curing temperature of said thermosetting resin.
7. Structure as claimed in claim 5 , wherein said thermoplastic material is PVC.
8. Structure as claimed in claim 1 , wherein the fibrous material of said at least one membrane is a synthetic or natural material.
9. Structure as claimed in claim 1 , wherein said synthetic or natural material comprises carbon or glass fiber.
10. Structure as claimed in claim 1 , wherein said frame has a laterally enlarged rear portion for supporting the buttocks of a user and an elongate front portion defining a longitudinal axis.
11. Structure as claimed in claim 10 , wherein at least one pair of differently deformable portions is located in the proximity of said widened rear portion.
12. Structure as claimed in claim 10 , wherein said at least one pair of differently deformable portions is provided at an outer peripheral edge of said frame, symmetrically with respect to said longitudinal axis.
13. Structure as claimed in claim 12 , wherein said frame comprises at least one recess along said outer peripheral edge.
14. Structure as claimed in claim 10 , wherein said frame comprises at least one stepped profile along said outer peripheral edge.
15. Structure as claimed in claim 10 , wherein at least one of said differentially deformable portions is located in said elongate front portion.
16. Structure as claimed in claim 15 , wherein said at least one differently deformable portion has an elongate shape along said longitudinal axis.
17. Structure as claimed in claim 10 , wherein at least one pair of differently deformable portions is located in the proximity of a junction between said elongate front portion and said rear widened portion.
18. Structure as claimed in claim 10 , wherein at least one of said differentially deformable portions is located at a junction between said elongate front portion and said rear widened portion.
19. A process for making a shape-memory saddle structure including a support frame comprising the steps of:
a) setting up a mold having one internal cavity of a predetermined shape;
b) depositing at least one layer of thermoplastic material in said mold;
c) setting up at least one elastically deformable membrane;
d) impregnating said elastically deformable membrane with a thermosetting resin;
e) laying said at least one elastically deformable membrane on said at least one layer of thermoplastic material, to define one or more deformable portions having shape-memory properties and defining areas of the support frame configured to be more susceptible to deformation than the rest of the support frame;
f) closing said mold and heating it to a predetermined temperature;
g) cooling said mold to a predetermined final temperature;
h) opening said mold and removing therefrom the support frame having an upper surface;
i) securing a yielding pad to the upper surface of said frame; and
j) laying a cover layer on said pad.
20. Process as claimed in claim 19 , further comprising a step e′) of cutting the fibers of one or both of the layer of thermoplastic material and the elastically deformable membrane to break their continuity.
21. Process as claimed claim 19 , wherein said predetermined temperature is close to the glass transition temperature of said thermosetting resin.
22. Process as claimed in claim 21 , wherein said predetermined temperature is 60° C. to 180° C.
23. Process as claimed in claim 21 , wherein said predetermined temperature is about 130° C.