Impact generator

Details Impact generator Impact generator

2000-04-21

2002-11-19

Smith, Scott A. (Department: 3721)

Tool driving or impacting

Impacting devices

With impact cushioning means

C173S094000, C173S205000

Reexamination Certificate

active

06481509

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an impact generator for rotating a weight by means of a rotary member and striking a struck member with the weight, thereby continuously generating impact force for working.
2. Description of the Related Art
An impact generator is a device for continuously generating impact force (shock force). Such impact generator may be applied to a crusher for crushing concrete or hardened asphalt in a road construction, a building site and the like, a reaper for cutting off fruit and branches of plants, and a root cutter for cutting off roots of plants, for example.
By way of example, Japanese Laid-Open Patent Publication No. Hei 7-164351 has disclosed an impact generator according to the prior art.
FIG. 5A
is a transverse sectional view showing the impact generator D
100
according to the prior art and
FIG. 5B
is a longitudinal sectional view showing the impact generator D
100
according to the prior art. The impact generator D
100
is applied to a reaper and serves to give continuous impact force to a cutting blade
191
. The impact generator D
100
converts rotating force transmitted from a power unit such as an engine into reciprocating impact force and transmits the reciprocating impact force to the cutting blade
191
.
As shown in
FIGS. 5A and 5B
, the impact generator D
100
comprises a rotary member
110
and a weight
130
. The rotary member
110
is rotatably supported in a casing
150
by means of rotary shafts
111
and
112
. The rotary member
110
has plate-shaped holding portions
113
and
114
. The plate-shaped holding portions
113
and
114
are connected to each other through a connecting shaft portion
115
. The connecting shaft portion
115
is positioned eccentrically from a center C
100
of rotation of the rotary member
110
. Elliptical holes
113
a
and
114
a
are formed on the plate-shaped holding portions
113
and
114
, respectively. A cylindrical weight
130
is held in the holes
113
a
and
114
a
. The holes
113
a
and
114
a
have diameters which are larger than the diameter of the weight
130
. Therefore, the weight
130
can freely move to some extent in the holes
113
a
and
114
a
. More specifically, the weight
130
is movably held by the rotary member
110
.
When the weight
130
performs a circular motion around the rotary shafts
111
and
112
of the rotary member
110
by the rotation of the rotary member
110
, the top of a tappet
192
positioned to interfere with the locus of the circular motion is struck with the weight
130
. The tappet
192
is supported movably in an axial direction thereof (in a right and left direction in FIGS.
5
A and
5
B). Therefore, the tappet
192
is struck, thereby giving an impact to the cutting blade
191
positioned on the left of the tappet
192
in
FIGS. 5A and 5B
. Thus, when the rotary member
110
is rotated, continuous impact force is given to the cutting blade
191
.
In the above-mentioned impact generator D
100
, the tappet
192
is struck with the weight
130
, thereby generating the impact force. However, when the tappet
192
is struck with the weight
130
, the weight
130
receives a reaction in a direction toward the center C
100
of rotation of the rotary member
110
from the tappet
192
. Then, the weight
130
collides with points P
101
and P
102
on internal walls defining the holes
113
a
and
114
a
which are the closest to the center C
100
of rotation. By the collision, the rotary shafts
111
and
112
supporting the rotary member
110
and bearings
151
and
152
supporting the rotary shafts
111
and
112
receive a shock. Accordingly, the load capacities of the bearings
151
and
152
should be increased.
By the collision, moreover, great vibrations are also given to a machine (a reaper or the like) to which the impact generator is applied. Further for this reason, great noises are made in some cases.
SUMMARY OF THE INVENTION
In consideration of above-mentioned circumstances, it is an object of the invention to relieve a shock to be given to a rotary shaft of a rotary member and a bearing supporting the rotary shaft.
In order to solve the above-mentioned problems, the invention provides an impact generator comprising a rotary member rotatably supported by a rotary shaft for being rotated upon receipt of rotating force, a weight movably held by the rotary member for striking a struck member, and a shock absorber provided between the weight and the rotary member for absorbing, by elastic force, a shock generated between the weight and the rotary member.
According to the impact generator described above, the shock force generated between the weight and the rotary member is absorbed by the shock absorber. Consequently, the shock to be given to the rotary member can be relieved. Accordingly, it is also possible to relieve the shocks to be given to the rotary shaft supporting the rotary member and a bearing supporting the rotary shaft.
The shock absorber can be provided in any configuration if it is provided between the weight and the rotary member to absorb the shock therebetween. For example, the rotary member may have two plate-shaped holding portions provided in almost parallel with each other for holding the weight, and a connecting shaft portion for connecting the two plate-shaped holding portions in a position which is eccentric from the center of rotation of the rotary member, and the shock absorber may be provided between the weight and the connecting shaft portion.
Moreover, any shock absorber capable of absorbing a shock by elastic force can be employed. For example, the shock absorber may be constituted by a coil spring, and a supporting hole may be formed in the connecting shaft portion of the rotary member, fitting one of ends of the coil spring therein to support the coil spring.
These objects as well as other objects, features and advantages of the invention will become more apparent to those skilled in the art from the following description with reference to the accompanying drawings.


REFERENCES:
patent: 1215056 (1917-02-01), Pauli
patent: 1824935 (1931-09-01), Thompson
patent: 2341438 (1944-02-01), Gossling
patent: 3127941 (1964-04-01), Sieber
patent: 3486569 (1969-12-01), Sieber
patent: 5002134 (1991-03-01), Yamada
patent: 5488997 (1996-02-01), Yamada
patent: 3405980 (1984-02-01), None
patent: 7-164351 (1995-06-01), None
patent: 09/193046 (1997-07-01), None

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