Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling facilitates relative axial motion between coupled...
Reexamination Certificate
1999-02-12
2001-02-13
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling facilitates relative axial motion between coupled...
C464S172000
Reexamination Certificate
active
06186901
ABSTRACT:
FIELD OF THE INVENTION
Accident-prevention standards are becoming increasingly stringent in every field and therefore also—and in particular—in the case of mechanical transmissions which are exposed as are (in the field of agricultural machinery in particular) cardan shafts—in particular of telescopic type—which already have protective means comprising a telescopic sleeve around the shaft and protective boots for the end forks of the shaft which form part of the respective cardan joints. In general, such a protective means is supported by sliding block means which can slide in an annular channel formed in the base of each of said two forks, in which base the respective tubular segment of the telescopic shaft is inserted.
BACKGROUND OF THE INVENTION
In conventional solutions, such as that illustrated in
FIGS. 1 and 2
(see for example FR-A-2.507.266 and FR-A-2.218.501), the two segments
1
and
3
of the shaft—which have a non-circular profile and the possibility of sliding in relation to one another—are connected to forks
5
and
7
respectively by means of pins
9
and
10
respectively, which pass through axial seats formed in the forks
5
and
7
, in which seats the ends of the segments
1
and
3
respectively are received. These seats can have a shape corresponding to that of the segments
1
and
3
for angular coupling. On the outside of the bases
5
A and
7
A of the forks
5
and
7
, that is to say at the opposite end to the arms
5
B and
7
B of the forks, there is an annular channel
5
C and
7
C respectively, which channels partly contain sliding blocks
12
A and
14
A respectively which form part of protective boots
12
and
14
for the cardan joints of which the forks
5
and
7
respectively form part. Integral with the protective boots
12
and
14
are protective sleeves
16
and
18
respectively which are coupled in a telescopically slidable manner and which are connected rotatably to the boots
12
and
14
respectively. By preventing the protective means constituted by the boots
12
and
14
and by the tubular sleeves
16
and
18
from rotating, the shaft constituted by the forks
5
and
7
and by the segments
1
and
3
can rotate, the surfaces of the channels
5
C and
7
C sliding relative to the sliding blocks
12
A and
14
A which support the protective means
12
,
16
,
18
,
14
defined above. The sliding blocks
12
A and
14
A which support the protective sleeve on the rotating shaft are located practically at the ends of the forks and at the ends of the associated protective boots. The supports of the boots
12
and
14
—which are constituted by these sliding blocks
12
A and
14
A—are therefore positioned virtually at the inner end of the respective protective boots
12
and
14
which project unsupported from the support sliding blocks
12
A and
14
A over the forks
5
and
7
and therefore over the cardan joints of which the arms
5
B and
7
B of the forks
5
and
7
form part. It follows from this that a load bearing down in the direction of arrow fc has to be supported directly by the structure of the respective boot such as
12
which in this case tends to be deformed until it actually comes into contact with the arms of the fork such as
5
B of the fork
5
, the result of which is a dangerous tendency of the shaft to pull round with it all the protective means constituted by the boots and by the sleeves, thus neutralizing the protective effect. The most recent standards aimed at countering the danger of accidents provide for stringent tests to prevent the abovementioned risks, and the aim of the invention is to modify the conventional structures represented in
FIGS. 1 and 2
in order to achieve greater protective effectiveness of the protective sleeves without greatly affecting the robustness and other strength characteristics which otherwise have to be provided exclusively by the shape of the boots. These and other aims and advantages will become clear from reading the following text.
SUMMARY AND OBJECTS OF THE INVENTION
Essentially, according to the invention, the base of the fork is formed with a circular cross-section essentially as far as the arms of the fork itself and the channel for the sliding block means is recessed in said base adjacently to said arms of the fork. In practice, said annular channel is formed between the arms of the fork and the diametral pin connecting the segment of the shaft to the base of the fork.
A protective boot for the cardan joint can comprise: a rigid annular component with a collar for engagement on the tubular component of the sleeve, a front wall with an end rim forming a support, a flexible skirt with an inner flange, and a flat-ring element forming the sliding block means. Said inner flange and said flat-ring element are fixed against said front wall. Such a protective means can also comprise a second, reinforcing rigid annular component.
The flat-ring element advantageously has a radial cut and radial slits and is fixed around its own outer periphery to the front wall of the rigid annular component.
REFERENCES:
patent: 3053062 (1962-09-01), Geisthoff
patent: 3080731 (1963-03-01), Atkinson
patent: 3091101 (1963-05-01), Atkinson
patent: 3136140 (1964-06-01), Atkinson
patent: 4107952 (1978-08-01), Geistoff
patent: 4411636 (1983-10-01), Buthe et al.
patent: 4435166 (1984-03-01), Bondioli
patent: 4443207 (1984-04-01), Buthe et al.
patent: 4747804 (1988-05-01), Benzi
patent: 5580314 (1996-12-01), Moriyama et al.
patent: 5772521 (1998-06-01), Herchenbach et al.
patent: 5800271 (1998-09-01), Herchenbach et al.
patent: 5902186 (1999-05-01), Gaukel
patent: 5971858 (1999-10-01), Aurora
Browne Lynne H.
McGlew and Tuttle , P.C.
Thompson Kenneth
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