Hose pump with friction drive of hollow, resilient roller means

Claim 1

A hose pump, comprising: a housing having a chamber therein and a pair of axially spaced first rolling surfaces in said chamber; a hose receiving arcuate groove having an inlet and an outlet, the axial center of said groove being located equidistant from said first rolling surfaces, the depth of said groove being less toward the radial center of said arc than at said inlet and outlet thereof; a shaft and means supporting said shaft for rotation, said shaft having axially spaced flanges thereon located symmetrical with respect to and axially outside of said first rolling surfaces, said shaft further having a pair of axially spaced second rolling surfaces radially aligned with and spaced radially inwardly from said first rolling surfaces and having a radial dimension less than said flanges; and a plurality of hollow, rigid cylindrical pinch rollers positioned around said shaft and between said flanges and held by said flanges against axial movement with respect thereto, said pinch rollers having an elastically deformable characteristic and having a diameter greater than said radial spacing between said first and second rolling surfaces whereby said pinch rollers are elastically compressed to an oval shape between said first and second rolling surfaces to thereby enhance a frictional rotary drive from said rotatable shaft to said pinch rollers and are free of engagement with said shaft between said second rolling surfaces.