Lift truck mast

An extensible mast having collapsed and extended positions, comprising:

• a. inner and outer mast sections nested inner within the outer and being relatively longitudinally extensible;
• b. each of said mast sections including two parallel laterally spaced rail members;
• c. said rail members of at least one of said mast sections carrying a plurality of rollers mounted for rotation about parallel axes;
• d. each of said rollers defining a peripheral surface and an end surface joined by a curved interconnecting surface;
• e. said rail members of said other mast section defining track surfaces engageable with said peripheral surfaces, and defining inclined surfaces adjoining said track surfaces and tangentially contactable with [the junctures of] said interconnecting [and said end] surfaces of said rollers to absorb thrust loads;
• and,
• f. said inclined surfaces being spaced from each of said rollers except at the points of tangency with said [end] interconnecting surfaces so that a clearance is provided between the interconnecting surfaces and corners of said rail members .

An extensible lift truck mast, comprising:

• a. inner and outer mast sections nested inner within the outer and being relatively longitudinally extensible;
• b. each of said mast sections including laterally spaced rail members;
• c. each of said rail members having spaced end flanges connected by a web;
• d. said webs and said end flanges of said inner section rail members overlapping said webs and said end flanges of said outer section rail members to define longitudinally extending trackways;
• e. said rail members of at least one of said mast sections carrying a plurality of rollers mounted for rotation about parallel axes, said rollers each having a peripheral surface and an end surface joined by a curved interconnecting surface;
• f. said rail members of the other of said mast sections having track surfaces defined on its end flanges for engaging said peripheral surfaces of said rollers;
• g. said webs of said other section rail members having cross sections of increased thickness near said track surfaces and joined to said track surfaces by a connecting surface , said increased thickness cross sections defining inclined surfaces that extend into tangential contact with the interconnecting surfaces near the junctures of said interconnecting and said end surfaces at angles within the range of about 1.degree. and 20.degree. relative to said end surfaces , and said web connecting surface being spaced from said rollers .