Self-supporting unit element staircase

DETAILED DESCRIPTION I claim: 1.
A staircase comprising a plurality of U-shaped supporting elements, each element having a horizontally extending base and vertically upwardly extending legs integrally connected to the base, a plurality of steps having opposed ends and marginal edges between said opposed ends and said marginal edges are longer than said opposed ends, means for clamping said step ends of each step to the legs of at least two of said U-shaped elements so that each step is supported above both bases of said two U-shaped elements with said step marginal edges parallel said elements bases, said U-shaped elements being spaced vertically one relative to another so as to define a predetermined pitch or rise for successive steps in the staircase.
2.
The staircase according to claim 1 wherein said U-shaped supporting elements are tubular in cross section and wherein said means for clamping said step ends to said U-shaped element legs comprises means for encircling said tubular element legs.
3.
The staircase according to claim 1 further comprising handrail defining parts, said U-shaped supporting element legs having upper ends, and means coupling said handrail defining parts to said element leg upper ends.
4.
The staircase according to claim 3 wherein at least some of said steps having non-rectangular generally trapezoidal shape, said supporting elements and steps defining a non-linear staircase.
5.
The staircase according to claim 3 wherein said handrail defining parts include vertically extending side parts extending from one end of at least one step to said handrail defining part.
6.
The staircase according to claim 3 wherein said handrail defining parts are secured to the upper ends of said upwardly extending legs, and said clamping means defined integrally at the ends of said steps whereby only said handrail defining parts, said steps, and said U-shaped supporting elements are required to assemble a complete staircase and handrail according to the present invention.
7.
The staircase according to claim 1 further comprising handrail defining parts that are so shaped as to define said desired pitch or rise of the staircase steps, each of said handrail parts being defined by a coupling sleeve adjacent one end of the handrail part and adapted to be received on the upper end of the U-shaped supporting leg, and each handrail part including an opposite end adapted to be received in the coupling means of an adjacent handrail part