| 摘要 |
According to the invention, a drill hammer (10) generally comprises an outer tube (55), a control casing jacket (60) inclusive of check valve (59) and a central tube (80) having radial passages (81, 83). A ram (75) is guided on central tube (80), onto the lower and preferably recessed end (84) of which the head of a drill steel (90) may slide. A cylinder liner (70) that may be provided with outer ribs (101) also guides ram (75) and is peripherally welded to outer tube (55) along a welding zone S of axial length l. Above control casing jacket (60), there is an adapter (40) comprising downstream channels (43) and carrying a blowing collar (50) provided with upwardly directed nozzles (53). A drive-transmitting sleeve (15) below a screw head (11) is joined to the adapter (40) either directly or via a shift unit (30) that guides a shaft (20) whose lower end (23) may form a slide valve relative to an upper adapter portion (41). From there, passages (42, 47) lead to a control casing jacket (62) having channels (63). Below a tubular body (61), there is between outer tube (55) and cylinder liner (70) a jacket chamber (68) of a free cross section at least as large as that of the narrowest among central passages (12, 22, 32, 42/47, 62, 82, 92) in the main components of the hammer, including the screw head (11), a shaft (20), a shift unit (30), an adapter (40), a tubular body (61), the central tube (80), and a shaft and the drill steel (87/90) of the drill hammer (10). Grooves, channels and bores (71, 72; 81, 83) in cylinder liner (70) and central tube (80) serve, together with recesses (76, 76') and bores (78, 78'), for controlling the movement of the ram (75).
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