End cap assembly

1. A fluid activated cylinder assembly, comprising:

an end cap having an annular protrusion; and

a hollow cylinder having an end zone, said cylinder applying compressive force to said annular protrusion in said end zone, said end zone having no accommodating cavity and no accommodating protrusion for said annular protrusion, said annular protrusion having a first ramped surface and a second ramped surface, said ramped surfaces being separated by a region of substantially constant diameter and enlarging in diameter toward a distal end associated with said end zone, said annular protrusion additionally including an abrupt reduction in diameter, said abrupt reduction in diameter being closer to said distal end than the ramped surfaces are to said distal end.

2. The assembly of claim 1 , wherein said end cap additionally includes a boss that abuts an end surface of said cylinder.

3. A fluid activated cylinder assembly, comprising:

an end cap having an annular protrusion; and

a hollow, substantially translucent, cylinder having an end zone, said cylinder applying compressive force to said annular protrusion in said end zone, said end zone having no accommodating cavity and no accommodating protrusion for said annular protrusion, said cylinder is substantially cylindrical internally and externally having no grooves, no holes and no protrusions and made of a resin and wetted fibers compound.

4. A cylinder assembly comprising:

a cylinder having an interior of a first diameter, said cylinder having an end zone and a distal end, said cylinder having no grooves in said end zone of said interior; and

an end cap having an annular protrusion of a second diameter, said annular protrusion at least partially in contact with said interior, said second diameter being larger than said first diameter, said annular protrusion additionally including an abrupt reduction in diameter, said abrupt reduction being closer to said distal end than said at least one ramped surface is to said distal end;

said annular protrusion including a first ramped surface and a second ramped surface, said ramped surfaces being separated by a region of substantially constant diameter and enlarge in diameter toward said distal end.

5. The assembly of claim 4 , wherein said end cap additionally includes a boss that abuts an end surface of said cylinder.

6. The assembly of claim 4 , wherein said cylinder is substantially cylindrical internally and externally having no grooves, no holes and no protrusions.

7. The assembly of claim 6 , wherein said cylinder is made of a resin and wetted fibers compound.

8. The assembly of claim 7 , wherein said cylinder is substantially translucent.

9. A method of assembling a cylinder device, comprising the steps of:

providing a hollow cylinder having an end zone and a distal end, said cylinder having no protrusions and no grooves in said end zone; and

pressing an end cap into an end of a cylinder, said end cap having an annular protrusion that at least temporarily displaces a portion of said cylinder, said annular protrusion having a first ramped surface and a second ramped surface separated by a region of substantially constant diameter, said ramped surfaces enlarging in diameter toward said distal end, said annular protrusion additionally including an abrupt reduction in diameter, said abrupt reduction in diameter being closer to said distal end than said at least one ramped surface is to said distal end.