US 7,516,964 B2
	Clamping chuck and key rod therefor
Andre Ubele, Kleinaspach (Germany); and Siegfried Gulde, Durrenwaldstetten (Germany)
Assigned to Schunk GmbH & Co. KG Spann-und-Greiftechnik, Lauffen (Germany)
Appl. No. 10/539,601 PCT Filed Dec. 19, 2003, PCT No. PCT/EP03/14651 § 371(c)(1), (2), (4) Date Jan. 17, 2006, PCT Pub. No. WO2004/056516, PCT Pub. Date Jul. 08, 2004.
Claims priority of application No. 102 59 959 (DE), filed on Dec. 20, 2002.
Prior Publication US 2006/0145432 A1, Jul. 06, 2006
Int. Cl. B23B 31/167 (2006.01)

U.S. Cl. 279—124  [279/6]

7 Claims

1. A powered clamping chuck for machine tools having a chuck body (1) and several clamping jaws (4) that are arranged movably in radial jaw guides (3) of the chuck body (1) and are displaceable together, by means of a drive, radially with respect to a chuck axis (A), the drive including key bars (5) that are slidably guided transversely to the chuck axis (A) for displacement of the clamping jaws (4) in the chuck body (1) and each comprise a tooth set (7) that is in engagement with a corresponding counter-tooth set (8) on an associated clamping jaw (4); a positioning mechanism being provided that comprises a releasing bolt (P) mounted rotatably in the chuck body (1) and a releasing key (S) that can be coupled to the releasing bolt (P) in order to displace, by way of a rotation of the releasing bolt (P), the key bar (5) or a coupling attachment (5b), comprising the tooth set (7), of the key bar (5) parallel to the chuck axis (A) between an upper working position and a lower jaw changing position in which the tooth set (7) of the key bar (5) is pulled back out of the counter-tooth set (8) of the clamping jaw (4) and the latter can be removed radially from the chuck body; and a locking device being provided which locks the releasing key (S) on the releasing bolt (P) and permits disengagement of the releasing key (S) only in the working position of the key bar (5), wherein the key bar (5) has locking means that allow a rotation of the releasing bolt (P) out of the rotational position corresponding to the lower jaw changing position of the key bar (5), into the rotational position corresponding to the upper working position of the key bar (5), if the tooth set (7) of the coupling attachment (5b) is in engagement with the counter-tooth set (8) of an associated clamping jaw (4), and that otherwise prevent rotation of the releasing bolt (P) into the rotational position corresponding to the upper working position, wherein the coupling attachment (5b) possesses on its underside a guide extension (11) that engages into a corresponding guide bore (17) of the key bar body, and wherein the coupling attachment (5b) is braced against the key bar body (5a) by way of compression springs (15), optionally via pusher pieces (16), and is pushed toward the clamping jaw (4).