Abstract: A portable grinder incorporates a safety clutch mechanism between the drive motor output and the grinding wheel shaft to prevent the grinding wheel from dislodging due to a malfunction of the motor. In the preferred embodiment, the clutch mechanism comprises a one-way or a free-wheeling clutch and a slip clutch in parallel between the motor rotor and the drive shaft. The one-way clutch transfers power from the motor rotor to the drive shaft and grinding wheel under normal operating conditions. In the event of a motor malfunction which suddenly locks the rotor, the clutch mechanism allows the drive shaft and grinding wheel to slow and stop in a controlled fashion thereby minimizing the possibility of the grinding wheel dislodging from the drive shaft.

Abstract: A free floating coupling device for use between drive and driven shafts, which coupling device consists of a clutch portion on each shaft, which clutch portions are held in spaced apart relation by a tubular member which serves as a bearing lubricant chamber. The coupling allows power to be transmitted from the drive shaft to the driven shaft, even when a slight mis-alignment exists between the shafts. The anti-friction bearings allow full torque to be exerted between the shafts.

Abstract: A clutch arrangement for a motor driven chain saw having a first clutch element driven by the motor shaft and a second clutch element normally engaged with the first clutch element but disengageable therefrom and a centrifugal clutch between the second clutch element and the drive sprocket for the saw chain. The second clutch element includes a spring disc and is axially yieldable between clutch engaged and clutch disengaged positions. A lever is provided moveable for disengaging the clutch elements and a brake member connected to the lever is operable for braking the drive sprocket when the clutch elements are disengaged.

Abstract: A transmission system for transmitting drive from at least two internal combustion engines to a single shaft comprises a clutch associated with each engine, an intermediate shaft connected to the hub part of each clutch and, in use, connected to its associated engine through a flexible coupling, a hollow shaft connected co-axially to the housing of each clutch, the intermediate shaft extending along and through its associated hollow shaft so that each clutch is remote from its associated engine. Each hollow shaft passes through a common gear housing and carries a gear wheel, the gear wheels on the hollow shafts meshing with a gear train in the gear housing to drive the driven shaft.

Abstract: A coil spring clutch connects a driving hub to a driven sleeve rotatable on the hub and the sleeve drives an output or second driven member through a torque limiting clutch. The spring is readily declutched by arresting rotation of its leading end, as by interposing a stop in the path of an out-turned tang on that end, and is re-engaged by releasing the leading end. Re-engagement is characteristically abrupt and harsh, and the torque-limiting clutch in series with the spring clutch limits torque stress on the spring so that the series assembly is usable in applications which would destroy the spring clutch alone. The torque-limiting clutch may be a fully-releasable centrifugal clutch, in which case, the spring declutching mechanism may be actuated in common with or in response to application of a brake to stop the second driven member, or may be a frictionally-engaged centrifugal clutch or a spring-biased friction clutch.