To effectively use the pick-up cover for the various kinds of pin arrays by providing the pick-up cover with an upper side portion, providing a wall member extended downward from the aforesaid upper side portion with an opened end part, and thereby letting these parts act as a pin engaging means.

The cover 10 is provided with an upper side portion 12. The portion 12 includes a smooth apex surface 14 and a lower surface, a pin engaging structural part 17 is projected out of the lower surface 16, and a substantially continuous wall part 18 is thereby formed. The wall part 18 includes face-to- face end wall parts 20 and 22, and face-to-face side wall parts 24 and 26. The aforesaid continuous wall part also includes an inner circumferential side part 28 and an outer circumferential part 30. The upper side part 12 includes an octagon shaped side part 32, and it is composed of side parts 34 through 48. Corner parts 50, 56 through 56, and 57 are formed in the inner circumferential side part 28 and the outer circumferentical part 30, and each corner part approaches to the alternate circumferential side part of the side part 30 of the upper side part 12. The action of the cover 10 is, in general, to permit the various kinds of pin arrays to be engaged with the inner circumferential side part 28 or the outer circumferential part 30.