Suspension for two-wheeled vehicle

A suspension for two-wheeled vehicles is provided which may arbitrarily adjust its spring characteristics almost without changing the initial load applied to the suspension spring so that the optimum spring characteristics may be selected depending upon the desired riding quality or road conditions. A pair of series-disposed helical or coil springs are fitted over a telescopic shock absorber and are spaced apart from each other by a spacer whose position with respect to the shock absorber is adjustable and which is retained in position by a stopper securely fitted over the shock absorber. The pair of helical springs have different forces, that is the load causing the maximum deflection of one helical spring is different from that causing the maximum deflection of the other helical spring. By the coaction between the spacer and the stopper and by a mechanism for causing the axial displacement of one of the spring seats fitted over the shock absorber, the preload applied to one.

1. In a two-wheeled vehicle, a combination comprising a telescopic shock absorber column having spaced ends and inner and outer surfaces, and including a first tubular element and a second element telescoped into said first element;

an annular spacer intermediate said ends of said column freely movable towards and away from one of said ends; and having an annular flange projecting radially of one of said surfaces;

abutment means adjustably positioned in circular grooves on one of said tubular surfaces of said column and operative for preventing movement of said spacer towards and away from the other of said ends;

a helical first spring of a first stiffness located intermediate said spacer and said one end and bearing upon one axial end of said flange;

a helical second spring of a different second stiffness mounted in precompressed condition intermediate said spacer and said other end and bearing upon the opposite axial end of said flange; and

adjusting means operative for adjusting the degree of precompression of said helical second spring, said springs being connected with one another in series so that loads tending to telescope said column together cause further compression of said second spring only after substantially complete compression of said first spring has taken place, said adjusting means including a cam portion received in said column and having a stepped cam face facing axially of said column in one direction, and a discrete cam seat portion intermediate one end of said second spring in engagement with said cam face, one of said portions being rotatable relative to the other portion so as to adjust the degree of precompression of said second spring.

2. A combination as defined in claim 1, wherein said spacer is accommodated in said column intermediate the ends thereof, and said abutment means is fixed with and projects into the interior of said column intermediate said ends.

3. A combination as defined in claim 2, wherein said first and second springs are both accommodated in the interior of said column.

4. A combination as defined in claim 3, wherein said cam face faces axially inwardly of said first element, and said cam seat portion is rotatable with reference to said cam portion and has an axial end facing away therefrom and in engagement with a said one end of said second spring.

5. A combination as defined in claim 4, wherein said adjusting means further includes a handle located exteriorly of said first element and operatively connected with said cam seat portion for effecting rotation of the same with reference to said cam face.

6. A combination as defined in claim 4, wherein said first and second springs are coaxial with one another.

7. A combination as defined in claim 1, wherein said spacer surrounds said first element, and said abutment means is provided on said first element intermediate the ends of the latter.

8. A combination as defined in claim 7; and further comprising a pair of stops on said column in the region of the opposite ends thereof, said springs each bearing upon said spacer and upon one of said stops, respectively, and exteriorly surrounding said column.

9. A combination as defined in claim 8, wherein said cam portion and said cam seat portion both surround said column, said cam seat portion being fixed to said column against rotation relative thereto and said cam portion being turnable relative to said column and to said cam seat portion.

10. A combination as defined in claim 9, wherein said springs are coaxial with one another.

11. In a two-wheeled vehicle, a combination comprising a telescopic shock absorber column having spaced ends and an inner surface, and including a tubular first element and a second element telescoped into said first element;

a spacer accommodated in said column intermediate the ends thereof and being freely movable towards and away from one of said ends;

abutment means adjustably positioned on said inner surface and projecting into the interior of said column intermediate said ends for preventing movement of said spacer toward and away from the other of said ends;

a helical first spring of a first stiffness accommodated in said column intermediate said spacer and said end and bearing upon one axial end of said spacer;

a helical second spring of a second stiffness accommodated in said column in precompressed condition intermediate said spacer and said second end and bearing upon the other axial end of said spacer; and

adjusting means at said one end and operative for adjusting the degree of precompression of said helical second spring, said spring being connected with one another in series so that loads tending to telescope said column together cause further compression of said second spring only after substantially complete compression of said first spring has taken place, said adjusting means including a portion having a stepped cam face facing axially inwardly of said first element, and a rotatable cam seat in said first element and having one axial end portion in engagement with said stepped cam face and another axial end portion in engagement with a proximal end of said second spring.

12. In a two-wheeled vehicle, a combination comprising a telescopic shock absorber column having spaced ends and including a tubular first element and a second element telescoped into said first element;

a spacer surrounding said column intermediate the ends thereof and being movable towards and away from one of said ends;; abutment means adjustably positioned on said outer surface and projecting outwardly, of said column intermediate said ends for preventing movement of said spacer toward and away from the other of said ends;; a helical first spring surrounding said column intermediate said spacer and said end and having a first stiffness;; a helical second spring surrounding said column in precompressed condition intermediate said spacer and said second end and having a different second stiffness; and; adjusting means at said one end and operative for adjusting the degree of precompression of said helical second spring, said springs being connected with one another in series, so that loads tending to telescope said column together cause further compression of said second spring only after substantially complete compression of said first spring has taken place, said adjusting means including a portion having a stepped cam face facing axially inwardly of said first element, and a rotatable cam seat on said first element and having one axial end portion in engagement with said stepped cam face and another axial end portion in engagement with a proximal end of said second spring.