| 摘要 |
PROBLEM TO BE SOLVED: To provide a percussive penetration testing apparatus for investigating the strength of a ground by penetrating a rod into the ground by hammering. SOLUTION: This percussive penetration testing apparatus comprises a rebound detection sensor 50 for detecting the rebound of a hammer 44 occurring when the penetration rod 2 is hammered by a hammer 44. The moving speed of an endless chain 35 is reduced by a rebound detection signal. Therefore, when the strength of the ground is large and the rebound of the hammer 44 occurs, it is detected by the rebound detection sensor 50. When the rebound is detected, the moving speed of the endless chain 35 is reduced, and the timing at which a locking member 37 is engaged with a claw 45 fitted to the hammer 44 is retarded. When the rebound of the hammer 44 ceases and the locking member 37 is engaged with the claw 45, there occurs no falling of the claw 45 by the rebound, and the locking member 37can be engaged with the claw 45 without applying impact thereto. The percussive penetration testing device is formed of: the hammer 44 of predetermined weight, which is guided by guide rails 43 in an ascendable/descendable manner; a penetration rod 2 which is penetrated into the ground when an impact by the hammer 44 is applied thereto; an engaging member 37 which is movable in parallel with the ascending/descending direction of the hammer 44; a claw 48 which is rotatably arranged at the hammer 44, and engageable with the rising engaging member 37; and canceling members 38 which are arranged on a rising path of the hammer 44 for rotating the claw 48 to cancel the engagement with the engaging member 37. The hammer 44 has a lower block 46, and an upper block 47 connected to the lower block 46 via a cushioning mechanism 50, and functions to rotatably support the claw 48 on the upper block 47. COPYRIGHT: (C)2009,JPO&INPIT
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