Information
-
Patent Grant
-
6799373
-
Patent Number
6,799,373
-
Date Filed
Thursday, June 6, 200222 years ago
-
Date Issued
Tuesday, October 5, 200419 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 083 788
- 030 381
- 030 382
- 030 383
- 030 517
- 030 340
- 030 520
- 030 384
- 030 385
- 030 386
-
International Classifications
-
Abstract
A portable work apparatus, especially a motor-driven chain saw (1), has a drive unit which is provided with a handle housing (3). The handle housing (3) includes an extension (9) which extends in the longitudinal direction of the work apparatus from a rearward handle (8) on the side facing away in the longitudinal direction from a guide bar (6) forward to the side facing toward the guide bar (6). The handle housing (3) is connected via antivibration elements to the drive unit. The work apparatus has a forward handle tube (4), which extends over the work apparatus transversely to the longitudinal direction and is attached with an end (10) to the free end of the extension (9) and with the other end (27) in the area of the rearward handle (8). At least one of the ends (10, 27) of the handle tube (4) is fixed via an antivibration element (11, 25, 26, 28, 34).
Description
BACKGROUND OF THE INVENTION
In a known motor-driven chain saw, forward and rearward handles are provided, which are connected by respective antivibration elements to the drive unit. The rearward handle comprises a handle which has an extension extending in the longitudinal direction of the chain saw. The extension has a forward end which is attached to a handle tube. The handle tube extends over the drive unit and is fixed with its other end to the handle housing. In practice, it has been determined that resonance frequencies occur under specific operating conditions and these resonance frequencies are a burden to the operator and contribute to making work with the apparatus tiring.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a work apparatus wherein the damping of vibrations is improved.
The portable handheld work apparatus of the invention includes a motor-driven chain saw and defines a longitudinal axis. The portable handheld work apparatus includes: a drive unit; a handle housing defining a rearward handle; antivibration means for connecting the handle housing to the drive unit; a guide bar connected to the drive unit; the handle housing having a first end facing away from the guide bar with the first end being in the longitudinal direction of the guide bar and the handle housing having a second end facing toward the guide bar; the handle housing having an extension member extending forwardly from the rearward handle at the first end to the second end; the extension member having a free end portion; a forward handle tube passing over the drive unit transversely to the longitudinal axis; the forward handle tube having a first end attached to the free end portion and a second end attached in the region of the rearward handle; and, one of the first and second ends of the forward handle tube being fixed via an antivibration element.
The transmission of vibrations to the handle tube (the vibrations occur in the handle housing or are transmitted thereby) are reduced by decoupling the handle tube from the handle housing by a vibration element at least at one end of the handle tube. The entire system is modified with respect to vibrations so that burdensome resonances are shifted out of the normal operating range and can no longer affect the operator. In an embodiment of the invention, both ends of the handle tube are attached to the handle housing via respective antivibration elements.
Advantageously, one of the ends of the handle tube is fixed via an antivibration element to the handle housing as well as to a housing part connected to the drive unit. In this way, the transmission of vibration is reduced especially effectively. The outer boundary line of a cross section of the handle tube advantageously encloses a smaller area at an end of the handle tube facing toward the antivibration element than in a center region of the handle tube. In this way, the space, which is available for accommodating the vibration-damping element and the attachment means, is increased. The end of the handle tube can have a flat shape or can have a smaller outer diameter than a center region of the handle tube.
The antivibration element advantageously has an approximately cylindrical form and is mounted in the longitudinal direction of the handle tube. A holder, which is provided on the handle housing, encloses the antivibration element at least partially. It is especially practical to mount the rearward end of the handle tube, which is attached directly to the handle housing, within the vibration-damping element.
According to another embodiment of the invention, the antivibration element is configured as a bushing having a collar and the bushing is mounted in a cutout approximately perpendicular to the longitudinal axis of the handle tube.
The antivibration element is advantageously configured to be an approximately flat component. The antivibration element is configured in two parts for the embodiment of the vibration-damping element in the form of a bushing as well as for the flat configuration. The vibration-damping element partially covers the facing sides of the handle housing and/or of the handle tube. This embodiment makes possible an advantageous constructive configuration especially for the attachment of the forward end of the handle tube attached to the extension of the handle housing. With an approximately flat configuration of the vibration-damping element, the handle tube and the handle housing can be attached separately from each other to the antivibration element. This is especially so for the attachment of the rearward end of the handle tube.
The handle housing (especially the extension of the handle housing) is attached to a first region of the antivibration element and, at a second region of the antivibration element, a housing part, which is connected to the drive unit (especially the motor housing), is attached. The first and second regions are spaced from each other in the longitudinal direction of the handle tube.
The antivibration element advantageously is made of microcellular polyurethane. The material ensures an excellent damping without affecting the ability of the operator to manipulate the work apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the drawings wherein:
FIG. 1
is a side elevation view of a motor-driven chain saw;
FIG. 2
is a side elevation view of the handle housing of a motor-driven chain saw having a handle tube;
FIG. 3
is a section view of a connection of the forward handle tube end to an extension of the handle housing;
FIG. 4
is a section view taken along line IV—IV of
FIG. 3
;
FIG. 5
is an exploded view of another connection of the forward handle tube end to the handle housing;
FIG. 6
is an exploded view of another connection of the forward handle tube end to the handle housing;
FIG. 7
is a further side elevation view of the handle housing of
FIG. 2
;
FIG. 8
is an exploded view of a connection of the rearward handle tube end to the handle housing;
FIG. 9
is a plan view of a holder for connecting the rearward handle tube end to the handle housing;
FIG. 10
is a section view taken along line X—X of
FIG. 9
; and,
FIG. 11
is a section view of a connection of the forward handle tube end to the handle housing and to the motor housing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
FIG. 1
shows a motor-driven chain saw
1
having a motor housing
2
, a handle housing
3
, a handle tube
4
, a protective device
5
for the hand and a guide bar
6
having a saw chain
7
arranged thereon. The motor housing
2
with the motor mounted therein defines the drive unit which is held on the handle housing
3
via antivibration elements.
As shown in
FIG. 2
, the handle housing
3
includes a rearward handle
8
which is mounted on the end lying opposite the guide bar
6
. The handle housing
3
further includes an extension
9
projecting outwardly and forwardly in the longitudinal direction of the chain saw
1
. The handle tube
4
has a forward end
10
which is attached to the free end of the extension
9
of the handle housing
3
.
FIGS. 3 and 4
show the attachment of the handle tube
4
to the extension
9
. The extension
9
includes a cylindrical holder
12
in the longitudinal direction of the handle tube
4
. The holder
12
has a slot extending in the longitudinal direction thereof and directed at an angle downwardly. The antivibration element
11
is mounted in the holder
12
and is likewise approximately cylindrical and has an outer diameter corresponding to the inner diameter of the holder
12
. The antivibration element
11
has an approximately parallelepiped-shaped portion extending outwardly and this portion projects through the slot in the holder
12
. A cylindrical component
13
is mounted within the antivibration element
11
. The component
13
is flat in its longitudinal direction and is provided with two bores and the outer diameter of the component
13
corresponds approximately to the inner diameter of the antivibration element
11
. The forward end
10
of the handle tube
4
is flattened to have an L-shape and is attached to the cylindrical component
13
with two screws
14
so that the handle tube
4
is in contact only with the parallelepiped-shaped portion of the antivibration element
11
and is not in contact with the extension
9
of the handle housing
3
. The screws
14
extend through spacer sleeves
15
. The spacer sleeves
15
prevent that the antivibration elements
11
become too greatly pressed together when tightening the screws
14
.
FIG. 5
shows another embodiment for the attachment of the forward end
10
of the handle tube
4
to the extension
9
of the handle housing
3
wherein the extension
9
has a cutout
16
which functions as a holder. The cutout
16
is formed on the lower side of the extension
9
and is in the longitudinal direction of the handle tube
4
. The contour on the lower end of the cutout
16
corresponds to the contour of the upper side of the U-shaped flattened end
10
of the handle tube
4
. The antivibration element is configured as a two-part bushing (
17
,
18
). The lower element
17
of the bushing has a lateral collar
19
at its lower end and the upper element
18
of the bushing has a collar
20
at its upper end. The collar
19
of the lower element
17
of the bushing defines a support surface between the forward end
10
of the handle tube
4
and the handle housing
3
; whereas, the collar
20
of the upper element
18
of the bushing lies between the extension
9
and a sleeve
21
which likewise has a collar. A screw
14
and a sleeve
21
project through both elements
17
and
18
of the bushing. The sleeve
21
has an internal thread and defines the counterpiece to the screw thread. The screw
14
and the sleeve
21
connect the forward end
10
of the handle tube
4
to the two elements
17
and
18
of the bushing and to the handle housing
3
. The sleeve
21
functions simultaneously as a spacer element in order to avoid the bushing from becoming pressed excessively when tightening the screw
14
. Two two-part bushings
17
and
18
, two screws
14
and two sleeves
21
are all provided to achieve good damping and to fix the handle tube
4
adequately to the extension
9
. The two upper elements of the bushings
17
, the two lower elements of the bushings
18
and the two sleeves
21
can each be configured as one part in order to facilitate assembly.
In a further embodiment shown in
FIG. 6
, the forward end
10
of the grip tube
4
is likewise configured to have a U-shape and the extension
9
has a cutout
16
on its lower side. The cutout
16
corresponds to the contour of the handle tube.
The antivibration element (
25
,
26
) is flat and configured as two parts and is approximately as wide as the handle tube
4
. The upper part
25
of the antivibration element is fixed with two screws
22
to the handle tube
4
. The two screws
22
project from the lower side through two bores
23
into the forward end
10
of the handle tube
4
. The forward end
10
of the handle tube
4
has a cutout
24
between the two bores
23
. The lower part
26
of the antivibration element is mounted below the cutout
24
and is somewhat greater than this cutout. The antivibration element (
25
,
26
) is fixed with two screws
14
between the forward end
10
of the handle tube
4
and the extension
9
of the handle housing
3
. The screws
14
project through the following: the lower part
26
of the element, the cutout
24
and the upper part
25
of the element. The screws
14
can be threadably fastened directly in the extension
9
or the screws can be threadably fastened with nuts or with sleeves provided with internal threads through openings in the extension
9
at the upper end thereof.
FIG. 7
shows a side elevation view of the handle housing
3
of
FIG. 2
wherein the rearward end
27
of the handle tube
4
is attached to the handle housing
3
. The rearward end
27
can likewise be connected to the handle housing
3
via antivibration elements.
FIG. 8
shows an antivibration element
28
which is configured to be flat and a cone
29
is formed on the end thereof and a cylinder
30
is formed on the outer side thereof. The cone
29
projects laterally and is tapered. The cylinder
30
is laterally so flattened that it fits into the end
27
of the handle tube
4
. The end
27
is configured to have a U-shape. The antivibration element
28
is fixed with a screw
31
on the rearward end
27
of the handle tube
4
. The screw
31
projects through the rearward end
27
of the handle tube
4
and is threadably engaged in the cylindrical part
30
or in the cone
29
of the antivibration element
28
. The flat end of the antivibration element
28
is fixed with three screws
32
on the handle housing
3
.
Another embodiment is shown in
FIGS. 9 and 10
.
FIG. 9
shows a holder
33
which is configured as a rectangular hollow profile. The holder
33
is fixed with a screw via a bore
35
on the handle housing
3
. As shown in
FIG. 10
, an antivibration element
34
is mounted within the holder
33
. The antivibration element
34
has a U-shaped cutout in its longitudinal direction and this cutout corresponds to the cross section of the rearward end
27
of the handle tube
4
. The holder
33
completely surrounds the antivibration element
34
in the peripheral direction. As indicated by broken lines in
FIG. 9
, the rearward end
27
of the handle tube
4
is mounted in the antivibration element
34
in its longitudinal direction and is fastened via a bore
35
by means of a screw in the tube-shaped holder
33
.
A further embodiment is shown in
FIG. 11
wherein the forward handle tube end
10
is connected to the extension
9
of the handle housing
3
as well as to the motor housing
2
via an antivibration element
36
. The forward end
10
of the handle tube
4
has a lesser diameter than the handle tube
4
and has, at its end, a collar
37
projecting toward the handle tube center. The handle tube end
10
is mounted within the substantially pot-shaped antivibration element
36
. The antivibration element
36
is thickened toward its open edge and is configured so as to be expanded and has an opening
38
in the center of the base lying opposite the open edge. The diameter of the opening
38
corresponds approximately to the diameter of the opening left free by the collar
37
on the forward end
10
of the handle tube
4
. The antivibration element
36
is mounted in an approximately cylindrical holder
39
in the extension
9
. The holder
39
extends in the axial direction of the handle tube end
10
. The handle tube end
10
is fixed to the extension
9
via a screw
40
. The screw
40
projects into the interior of the handle tube end
10
through the opening
38
and the opening left clear in the collar
37
and is threadably fastened in the handle tube end
10
in a sleeve
41
having an internal thread. The sleeve
41
has an end facing away from the screw head. At this end, the sleeve
41
has a shoulder which has axial and radial play to the inner wall of the end
10
of the handle tube and functions to prevent a tear-off. The motor housing
2
surrounds the expanded end of the antivibration element
36
and is connected via a substantially cylindrical antivibration element
42
to the end of the extension
9
. This end surrounds the base of the antivibration element
36
.
The extension
9
has an end which encloses the base of the antivibration element
36
. At this end, a disc
43
is mounted between the antivibration element
36
and the extension
9
and this disc defines a support surface for the sleeve
41
. The sleeve
41
avoids a pressing together of the antivibration element
36
which is too great when the screws
40
are tightened.
The embodiments shown for attaching the forward end
10
of the handle tube
4
via an antivibration element to the handle housing
3
can also be provided for the attachment of the rearward end
37
of the handle tube
4
and vice versa.
It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.
Claims
- 1. A portable handheld work apparatus including a motor-driven chain saw, the portable handheld work apparatus defining a longitudinal axis and comprising:a drive unit; a handle housing defining a rearward handle; antivibration means for connecting said handle housing to said drive unit; a guide bar connected to said drive unit; said handle housing having a first end facing away from said guide bar in the longitudinal direction of said guide bar and said handle housing having a second end facing toward said guide bar; said handle housing having an extension member extending forwardly from said rearward handle at said first end to said second end; said extension member having a free end portion; a forward handle tube passing over said drive unit transversely to said longitudinal axis; said forward handle tube having a first end attached to said free end portion and a second end attached in the region of said rearward handle; and, an antivibration element mounted between at least one of said ends of said forward handle tube and said handle housing so as to cause said forward handle tube itself to be decoupled from said handle housing as to vibration.
- 2. The work apparatus of claim 1, wherein said antivibration element is a first antivibration element; said work apparatus comprises a second antivibration element; and, said first and second antivibration elements are provided for attaching said first and second ends, respectively.
- 3. The work apparatus of claim 1, wherein one of said first and second ends is attached via said antivibration element to said handle housing and to a housing part connected to said drive unit.
- 4. The work apparatus of claim 1, wherein said forward handle tube has a cross-sectional area at said antivibration element which is less than the cross-sectional area at the center region of said forward handle tube.
- 5. The work apparatus of claim 1, wherein said antivibration element has an approximate cylindrical form and is mounted in the longitudinal direction of said forward handle tube; and, said work apparatus further comprises a holder on said handle housing and said holder is configured to at least partially enclose said antivibration element.
- 6. The work apparatus of claim 1, wherein said one end of said forward handle tube is mounted within said antivibration element.
- 7. The work apparatus of claim 1, wherein said extension member has a cutout formed therein; said antivibration element is configured as a bushing having a collar; and, said bushing is mounted in said cutout approximately perpendicular to the longitudinal axis of said forward handle tube.
- 8. The work apparatus of claim 1, wherein said antivibration element is made of microcellular polyurethane.
- 9. The work apparatus of claim 1, wherein said antivibration element is configured as a flat structure.
- 10. The work apparatus of claim 9, wherein said antivibration element comprises first and second parts which partially cover at least one of said ends of said handle housing facing toward said parts and the ends of said handle tube facing toward said parts.
- 11. The work apparatus of claim 9, wherein said handle tube and said handle housing are attached separate from each other at said antivibration element.
- 12. The work apparatus of claim 1, wherein said handle housing is attached at a first region of said antivibration element and a housing part connected to said drive unit is attached at a second region of said antivibration element.
- 13. The work apparatus of claim 12, wherein said extension member of said handle housing is attached at said first region of said antivibration element.
- 14. The work apparatus of claim 12, wherein said first and second regions are spaced from each other in the longitudinal direction of said handle tube.
- 15. A portable handheld work apparatus including a motor-driven chain saw, the portable handheld work apparatus defining a longitudinal axis and comprising:a drive unit; a handle housing defining a rearward handle; antivibration means for connecting said handle housing to said drive unit; a guide bar connected to said drive unit; said handle housing having a first end facing away from said guide bar with said first end being in the longitudinal direction of said guide bar and said handle housing having a second end facing toward said guide bar; said handle housing having an extension member extending forwardly from said rearward handle at said first end to said second end; said extension member having a free end portion; a forward handle tube passing over said drive unit transversely to said longitudinal axis; said forward handle tube having a first end attached to said free end portion and a second end attached in the region of said rearward handle; one of said first and second ends of said forward handle tube being fixed via an antivibration element; and, said one end of said forward handle tube being mounted within said antivibration element.
- 16. A portable handheld work apparatus including a motor-driven chain saw, the portable handheld work apparatus defining a longitudinal axis and comprising:a drive unit; a handle housing defining a rearward handle; antivibration means for connecting said handle housing to said drive unit; a guide bar connected to said drive unit; said handle housing having a first end facing away from said guide bar with said first end being in the longitudinal direction of said guide bar and said handle housing having a second end facing toward said guide bar; said handle housing having an extension member extending forwardly from said rearward handle at said first end to said second end; said extension member having a free end portion; a forward handle tube passing over said drive unit transversely to said longitudinal axis; said forward handle tube having a first end attached to said free end portion and a second end attached in the region of said rearward handle; one of said first and second ends of said forward handle tube being fixed via an antivibration element; said antivibration element being configured as a flat structure; and, said antivibration element including first and second parts which partially cover at least one of said ends of said handle housing facing toward said parts and the ends of said handle tube facing toward said parts.
Priority Claims (1)
Number |
Date |
Country |
Kind |
101 28 188 |
Jun 2001 |
DE |
|
US Referenced Citations (17)