Abrading – Frame or mount – Portable abrader
Patent
1994-03-21
1995-11-07
Rachuba, Maurina T.
Abrading
Frame or mount
Portable abrader
451359, B24B 2300
Patent
active
054643651
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention concerns a motor-driven hand-held machine tool according to the generic part of claim 1.
A hand-held machine tool of the generic type is known from U.S. Pat. No. 4,735,020. Its work spindle can be stopped or braked by a spindle stop device and the screwing moment can then be applied by the drive motor for loosening the fastening nut for the grinding tool. The fastening nut may be loosened from the work spindle entirely by hand.
The known hand-held machine tool has the disadvantage that when the work spindle is suddenly stopped after turning off the motor by actuating the spindle stop device, the grinding disk tends to continue rotating as a result of its inertia and, in so doing, to loosen itself and the clamping device from the work spindle.
This unintentional loosening of the clamping device can cause the grinding disk to disengage from the work spindle at high speeds and endanger the operator or bystanders as a result of its high inherent energy.
ADVANTAGES OF THE INVENTION
In contrast to the prior art, the hand-held machine tool according to the invention with the characterizing features of claim 1 has the advantage that an unintentional loosening of the disk-shaped tool, in particular the grinding disk, is prevented also when actuating the spindle stop device at high speeds of the work spindle. This results in a great increase in safety.
Further advantageous constructions of the invention result from the dependent claims.
DRAWING
Embodiment examples of the invention are explained in more detail in the following description with reference to the accompanying drawing.
FIG. 1 shows a hand-held machine tool in a first embodiment example of the invention;
FIG. 2 shows a detail of a second embodiment example of the invention; and
FIG. 3 is another view of the second embodiment example according to FIG. 2 .
DESCRIPTION OF THE EMBODIMENT EXAMPLES
The angle grinder 1 shown in FIG. 1 in a sectional view as seen from the front has a motor housing 3 and a gear unit housing 5. A work spindle 7 with a lathed or turned collar 9 is held in a bearing 11 in the gear unit housing 5. Axially adjacent thereto, a stepped sleeve 13 carrying a collar 15 at its upper end is shrunk on to the work spindle 7. On its side remote of the collar 15, the stepped sleeve 13 is arranged in an additional bearing 17 so as to be rotatable, but secured against falling out.
The sleeve 13 supports a bevel gear 19 on its collar 15 in such a way that it is fixed with respect to rotation relative thereto. A spindle stop device 21 arranged in the gear unit housing 5 is associated with the bevel gear 19. The spindle stop device 21 substantially has a pressure pin 25 which is supported so as to be axially displaceable against a spring 23 and can lock into recesses 27 on the outer circumference of the bevel gear 19. By catching in these recesses, it can stop the bevel gear 19 and accordingly the work spindle 7.
A grinding disk 33 is clamped on the free end of the work spindle 7 between an inner flange 29 and an outer flange 31. The inner flange 29 with its bore hole is arranged so as to be rotatable in a defined manner and, on the side of the work spindle 7 remote of the free end, so as to be displaceable axially in a defined manner as far as the collar 35. The outer flange 31 fits on an external thread 37 on the free end of the work spindle 7, the external thread 37 having a slope angle. The grinding disk 33 has a central recess 39 by which it overlaps the work spindle 7 with play. On its side remote of the grinding disk 33, the inner flange 29 carries a gear-like wedge body 41 with an axial wedge face 43 which slopes upward toward the right as seen in the viewing direction at an angle and is supported at an axial counter-wedge face 45 of an approximately U-shaped recess 47 in the end face 49 of the sleeve 13, which axial counter-wedge face 45 slopes upward in the same direction. The lateral defining walls 51, 53 of the U-shaped recess 47 act as radial stops. The U-shaped recess 47 has roughly twice the width of th
REFERENCES:
patent: 3899852 (1975-08-01), Batson
patent: 3912411 (1975-10-01), Moffat
patent: 4400995 (1983-08-01), Palm
patent: 4637170 (1987-01-01), Block
patent: 4735020 (1988-05-01), Schulz et al.
patent: 5042207 (1991-08-01), Kirn
patent: 5259145 (1993-11-01), Fushiya et al.
Rachuba Maurina T.
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
Motor-driven hand-held machine tool does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Motor-driven hand-held machine tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motor-driven hand-held machine tool will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-194157