BRIEF DESCRIPTION OF THE DRAWING
The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
FIG. 1 is a side view half in axial section through a chuck according to the invention;
FIG. 2A is a section taken along line II-II of FIG. 1 in the locking position of the latch;
FIG. 2B is a view like FIG. 2A in the freeing position of the pawl;
FIG. 3A is a section taken along line III-III of FIG. 1 in the locking position; and
FIG. 3
b is a view like FIG. 3A in the freeing position.
SPECIFIC DESCRIPTION
As seen in FIG. 1 a drill chuck 1 has a chuck body 2 centered on an axis 7, and a tightening sleeve 3 that is coaxially mounted on the chuck body 2 and is axially fixed on a jaw holder 4 that is also rotatably mounted but axially fixed on the chuck body 2. Jaws 5 are axially and radially shiftable in respective slots 23 in the jaw holder 4 and are radially slidable in axially forwardly open slots of a pusher 22 having a stem centrally threaded into the chuck body 2. Thus, as is standard, rotation of the sleeve 3, jaw holder 4, and pusher 22 relative to the chuck body 2 in a tightening direction will shift the jaws 5 axially forward and radially together, and opposite rotation in a loosening direction will shift them axially backward and radially apart.
The drill chuck 1 also comprises a latch 6 having a ring of teeth 8 here formed on the chuck body 2 and centered on the chuck axis 7, and a pawl 10 which is pivoted on the jaw holder 4 and engages with the ring gear 8 under the force of a sprang 9. The latch 6 prevents the chuck body 2 and the pawl 10 from rotating relative to each other and releasing the jaws 5 when the pawl 10 is engaged with the ring gear 8, but does not hinder relative rotation in the tightening direction, when the latch 6 simply ratchets over the teeth 8. The pawl 10 is moved between its locking position (FIG. 2A), in which it inhibits loosening of the chuck, and its freeing position (FIG. 2B) by a pawl 19 described below.
FIG. 1 shows an embodiment in which the ring gear 8 is provided on the chuck body 2, and the tightening sleeve 3 has a two-piece design together with an inner sleeve 21 which has the cam 19 and is used for adjusting the pawl 10, and which in the illustrated embodiment allows the tightening sleeve 3 to rotate with respect to the jaw holder 4 so that the axial front portion of the tightening sleeve 3 may be connected to the jaw holder 4 by even one thread.
FIGS. 3A and 3B show that a stop 20 is associated with the jaw holder 4, and a counter,stop 12 is associated with the inner sleeve 21 of the tightening sleeve 3 for defined limitation of the relative rotation of the tightening sleeve 3 with respect to the jaw holder 4, between the first end position corresponding to the locking position of the pawl 10 and a second end position corresponding to the freeing position thereof. Since the inner sleeve 21 is rotatable with respect to the jaw holder 4, the axial front end of the tightening sleeve 3, as previously described, may be rotationally fixed to the jaw holder 4.
The drill chuck 1 also comprises a retaining device, as shown in FIGS. 3A and 3B. This retaining device comprises locking seats 13 associated with the first end position and with the second end position and situated between the jaw holder 4 and the tightening sleeve 3. The retaining device only allows rotation of the inner sleeve 21 with respect to the jaw holder 4, at least in the rotational direction of the tightening sleeve 3 corresponding to the clamping, once a predetermined clamping force has been attained. In practice, this occurs by the fact that the jaws 5 bear on a tool shaft when the drill chuck 1 is clamped, so that the further displacement of the jaws 5 is against greater resistance, which requires application of increased torque when the tightening sleeve 3 is rotated, and in this operating situation the retaining device is secured in the locking position of the pawl 10 with the ring gear 8.
To allow the drill chuck 1 to be opened for tool replacement, the pawl 10 must be disengaged from the ring gear 8, 15 for which purpose the radial cam 19 associated with the tightening sleeve 3 for adjustment of the pawl 10 when the tightening sleeve 3 is rotated in the loosening direction corresponding to release of the jaws 5. The radial cam 19 is then operational when the first end position and the second end position are changed once again; i.e. the retaining device also changes the locking seat 13.
FIG. 1 shows that the tightening sleeve 3, i.e. the inner sleeve 21 in the two-piece design shown, is connected in a rotationally fixed manner to an outer control sleeve 11, carried on its inner surface, and which supports the radial cam 19 and also may include the counterstop 12 and the locking seats 13, which in FIG. 3, however, are associated with the inner sleeve 21, which has a sleeve collar in which a first recess 15 is cut out and whose edge forms the counterstop 12. However, as described above, the control sleeve 11 may also be associated with the sleeve collar 14 in order to make beneficial use of the material properties thereof. The sleeve collar 14 also has a second recess 16 cut out for a second set of locking seats 13 formed by a catch spring 17 fitted in the second recess 16, the catch spring 17 having a locking cam 18 whose edges form the second set of locking seats 13. The edges of the first recess 15 and second recess 16 are crimped, resulting in an overall greater material thickness of the sleeve collar 14.
The control sleeve 11 also has the radial cam 19 for shifting the pawl 10 from the engaged position with the ring gear 8 to the disengaged position when the tightening sleeve 3 is rotated in the rotational direction corresponding to release of the jaws 5. Reference is made to FIG. 2, which shows that the radial cam 19 is set into the control sleeve 11, and therefore may also be produced in a particularly economical manner. The control sleeve 11 is made of metal.
Patent Application
20070273109
