Phillip W Alexander

US Patent:

46502599, Mar 17, 1987

Filed:

Nov 12, 1985

Appl. No.:

6/796831

Inventors:

Phillip W. Alexander - Davenport IA
Michael S. Freberg - Davenport IA
Keith A. Howell - Davenport IA
James E. Johnston - Geneseo IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

B62D 5514
B62D 5530

US Classification:

305 10

Abstract:

Method and apparatus for selectively tensioning an endless, inextensible elastomeric belt entrained about a cooperating drive structure and idler structure having respective axes of rotation. A roller frame joined to a vehicular main frame supports the idler structure and constrains movement thereof to a longitudinal recoil path. The drive and idler structures are biasingly separated by a compression spring which exerts biasing force thereon in opposite longitudinal directions through a drive strut and an idler strut, respectively. The idler strut is connected to the idler structure longitudinally in front of the idler's axis. The length of one of the struts is adjustable to provide the desired tension in the spring and, thus, the entraining belt. Increases in tension are preferably provided by displacing one component member of the one strut relative to a second component member thereof-one of such members being reciprocatably receivable in the other and provided with a seal therebetween such that the two members cooperatively define a pressurizable chamber. Pressurized fluid, when transmitted into the pressurizable chamber, provides relative longitudinal displacement of the two members so as to decrease the spring and belt tension.