Question 49 OSE02 - Assistant Engineer - OSV

The Correct Answer is D **Explanation for Option D (Correct Answer):** The clutch described, a pneumatic Airflex clutch (often manufactured by Eaton/Fawick or similar designs), is structurally a constricting type clutch. It consists of an outer annular rubber tube/element reinforced with cord (the bladder) mounted on a hub. When compressed air is introduced into the bladder, the bladder **constricts** (squeezes inward) to frictionally engage against the inner surface of an outer rotating cylindrical component, which is correctly termed the **clutch drum** (or flywheel rim). Therefore, the clutch is a constricting type and constricts to engage against the clutch drum when inflated. **Explanation for Incorrect Options:** * **A) The clutch is a constricting type clutch and constricts to engage against the clutch gland when inflated.** This option correctly identifies the clutch as a constricting type and describes the constriction action, but it misidentifies the mating component. The term "clutch gland" typically refers to a sealing mechanism or a packing device, not the primary friction surface (the clutch drum). * **B) The clutch is an expanding type clutch and expands to engage against the clutch drum when inflated.** This is incorrect. An expanding type clutch (like a typical pneumatic drum brake or an older style expanding shoe clutch) pushes *outward* to engage. The Airflex constricting design pushes *inward*. * **C) The clutch is an expanding type clutch and expands to engage against the clutch gland when inflated.** This is incorrect on both counts. It misidentifies the clutch type (it is constricting, not expanding) and misidentifies the component it engages against (it engages the drum, not the gland).