WE CLAIM:
1. A clamp apparatus (10, 150) in which, by rotation of a pair of clamp arms (14, 16), a
workpiece is clamped between one of the clamp arms and another of the clamp arms,
comprising:
a body (12);
a drive unit (18) disposed on the body (12) and which outputs a driving force along an axial direction;
a pair of clamp arms (14, 16) supported rotatably on the body (12), the clamp arms (14, 16) being arranged face- to-face with each other;
a driving force transmission mechanism (20, 152), which transmits a driving force of the drive unit (18) to the clamp arms (14, 16), to thereby cause rotation of the clamp arms (14, 16);
characterized in that
a cover member (36) disposed detachably with respect to the body (12), and which covers the drive unit (18) and a portion of the clamp arms (14, 16); and
an unloading tray (22) disposed inside of the cover member (36) at a position below the clamp arms (14, 16) in the direction of gravity, the unloading tray (22) being removable from the body (12),
wherein the cover member includes openings through which ends of the pair of clamp arms are inserted.
2. The clamp apparatus as claimed in claim 1, wherein, in the cover member (36), the unloading tray (22) is disposed in facing relation to a pair of openings (46) into which portions of the clamp arms (14, 16) are inserted.
3. The clamp apparatus as claimed in claim 1 or 2, wherein the unloading tray (22) is removably fixed with respect to the body (12) by a fixing member (106).
4. The clamp apparatus as claimed in any one of claims 1 to 3, the driving force transmission mechanism (20) comprising cam members (56) including pressing surfaces (60), which are inclined at a predetermined angle with respect to a driving direction of the drive unit (18), the cam members (56) being disposed detachably with respect to ends of the clamp arms (14, 16), wherein pressing members (88a, 88b) of the driving force transmission mechanism (20) abut against the pressing surfaces (60), and the cam members (56) are pressed by the pressing members (88a, 88b).

5. The clamp apparatus as claimed in claim 4, wherein the pressing members (88a, 88b) comprise rollers, which are rotatably disposed with respect to a displacement body (86) that is displaced linearly under a driving action of the drive unit (18).
6. The clamp apparatus as claimed in any one of claims 1 to 3, the driving force transmission mechanism (152) including a displacement body (86) disposed on an end of the drive unit (18), and link arms (156), which are pivotally supported, respectively, on ends of the clamp arms (14, 16), the driving force of the drive unit (18) being transmitted to the clamp arms (14, 16) through the link arms (156).
7. The clamp apparatus as claimed in claim 1, the unloading tray (22) comprising: a main body portion (102) that is formed in a flat shape; and
plural wall portions (104), which are bent respectively on outer edges of the main body portion (102),
wherein on the unloading tray (22), the wall portions (104) are arranged to extend upwardly.