Machine element or mechanism – Gearing – Rotary bodies
Reexamination Certificate
2000-05-18
2002-08-20
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Gearing
Rotary bodies
C074S820000, C384S045000
Reexamination Certificate
active
06435051
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a driving cam of a geneva mechanism. As generally known, a geneva mechanism is constructed as follows. While a circular arcuate convex of a driving wheel and a circular arcuate concave of a driven wheel are coupled and sliding, the driven wheel is detained right at the place without rotating, and when a pin on the driving wheel is inserted into one of the slots of the driven wheel and then pulled out, the driven wheel is rotated to a predetermined degree.
It goes without saying that the transfer loss of energy is decreased, because the circular arcuate convex and the circular arcuate concave are sliding smoothly almost without any resistance.
2. Description of the Related Art
In the Japanese Utility Model Patent Laid-open No. 1985-64357, an art has been disclosed that the sliding resistance is reduced by disposing rollers successively in the circular arcuate convex.
In the above mentioned prior art, however, it is difficult to process an arrangement of the pins supporting the rollers in a complete round shape, and there is a defect of rather increasing resistance if an irregularity exists in arrangement of dthe rollers.
As opposed to the above described Publication, in the Japanese Patent No. 2788218, a mechanism holding balls(rotating bodies) inside a annular groove which is formed in a circular arcuate convex of divided wheel(driving rotating body) has been disclosed. However, a detailed structure of holding the balls is that, as shown in
FIG. 9
, after divided grooves
15
A,
15
B of having sections of about ¼ of the circular arc are formed in the opposite surfaces of a pair of male and female cam members
11
A,
11
B, and then a annular groove
15
is formed by coupling a pair of cam members
11
A,
11
B with bolt
13
, the balls
14
are held inside this annular groove
15
so as to be in contact with a circular arcuate concave
3
(refer to
FIG. 7
of the above described Publication).
However, firstly there are problems that the processing of matching the circular arcs precisely is very difficult when the annular groove
15
is formed by coupling, because the divided grooves
15
A,
15
B have to be formed individually, and the smooth rotation of the balls
14
can not be expected because the processing error is increasing. Secondly there are many causes to decrease processing accuracy such as of positioning of bolting hole because the divided grooves
11
A,
11
B are required to be assembled precisely without being displaced to the radial direction, when the male cam member
11
A and female cam member
11
B are coupled with bolt
13
.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a driving cam in which grooves of radial direction, which hold rotating bodies such as balls, can be formed precisely and have a good roundness, and smooth rotation of the rotating bodies can be guaranteed, and which does not affect the precision of the grooves formed in a radial direction when assembled.
To achieve the above object, in the driving cam of the present invention, a peripheral groove is formed concentrically with the driving shaft on a circular arcuate peripheral surface of a lacked circular plate core member, and rotating bodies disposed in the peripheral groove are hold by circular arcuate rims formed at the peripheral edge of covers which are attached to the top and the bottom of the core member.
Preferably, with a path of the rotating bodies being formed along the entire periphery, the rollers are cyclically rotated endlessly. The sectional form of the above described peripheral groove may be triangle, quadrangle, trapezoid, round, oval or the like.
REFERENCES:
patent: 5439294 (1995-08-01), Rixen
patent: 5640768 (1997-06-01), Teramachi
patent: 5906134 (1999-05-01), Yamada
patent: 6234047 (2001-05-01), Yamada
patent: 2047839 (1980-12-01), None
Fenstermacher David
Sheridan Ross PC
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