Locking plate for adjustable arms

A windshield wiper arm comprising a channel-shaped section pivotally carried by an attaching section, an elongate arm extension member extending into the outer end of said channel-shaped member, a latching shim nested in said channel-shaped member in engagement with one end portion of the arm extension, said shim is elongate and has a channelled-out upper portion shaped to generally conform to the shape of the arm extension and wherein said arm extension nests in said channelled-out portion, lever means pivotally connected between the side walls of the channel-shaped member, and eccentric means on said lever in engagement with a portion of said locking shim whereby one portion of said eccentric bears against said shim to lock the shim and arm extension relative to the channel member and another portion of said eccentric bears against said shim to permit the arm extension to be moved relative to the channel member, and said shim has a hollowed-out lower portion in alignment with the eccentric on the lever to provide a bearing surface for said eccentric when said eccentric is moved into locking position by said lever means.