Abstract: A combination yard maintenance apparatus used for lawn mowing, leaf clearing and snow blowing comprises a blade assembly having an elongated support member for rotatably mounting to a drive shaft and two shovelling surfaces disposed at opposite ends of the elongated support member extending from the elongated support member downwardly and laterally opposite one from the other. Each shovelling surface has a lower edge with a cutting edge, an upper edge, an inner edge and an outer edge. The present invention also provides a clutch mechanism for engaging and disengaging an input shaft from an output shaft comprising a first and a second threadable engagement associated with the input shaft and output shaft respectively, and an initiator for inducing the engagement of the first and second threadable engagements. A friction-drive self-propelling system is also provided, comprising a driving wheel and a friction disk wherein the driving wheel has central recessed portion.

Abstract: The present invention refers to a synchronizer sleeve, and a method of manufacturing a synchronizer sleeve for a change speed gear. The synchronizer sleeve comprises in a known manner a shift fork recess opening towards the outer peripheral surface, and a tooth arrangement formed at its inner peripheral surface. The synchronizer sleeve according to the invention, which can be manufactured at a low price without affecting the wear to resistance, is characterized by a surface hardness of the shift-force recess, which is set by cold rolling, wherein the tooth arrangement is hardened locally, in particular it is hardened inductively. In the method of manufacturing the synchronizer sleeve according to the invention the shift fork recess is ready worked by cold rolling.