Tool driving or impacting – Impacting devices – Hammer head driven by relatively moving motion transmitting...
Reexamination Certificate
1999-05-27
2001-06-26
Vo, Peter (Department: 3721)
Tool driving or impacting
Impacting devices
Hammer head driven by relatively moving motion transmitting...
C173S094000, C173S128000, C173S212000
Reexamination Certificate
active
06250401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary impacting apparatus capable of providing high-frequency impacting force.
2. Description of the Related Art
Generally, an impacting apparatus such as a concrete breaker utilizes expansive force of compressed air or a combination of a motor and a crank mechanism for reciprocating an impacting piston in the main body. When reciprocated, the impacting piston repetitively hits a reciprocating implement supported at an end portion of the main body in an axial direction.
In the impacting apparatus of the above type, the impacting piston is forcibly reciprocated, so that the main body of the impacting apparatus will unfavorably be vibrated due to reaction from the impacting piston in motion. In addition, it is difficult to increase the frequency of reciprocation of the impacting piston due to the inertial mass of the impacting piston.
In order to overcome the above problems, the applicant of the present application has proposed a rotary impacting apparatus as shown in
FIG. 5
of the accompanying drawings. The illustrated rotary impacting apparatus includes a rotor
6
which is rotatably supported by a housing
5
, and a reciprocative implement
14
which is reciprocatively held by the housing
5
. The reciprocative implement
14
includes an auxiliary reciprocating member
14
a
. The rotor
6
loosely retains an impact member
12
in oval retaining holes
11
formed in flanges
6
a
,
6
b
of the rotor
6
. The flanges
6
a
,
6
b
are connected to each other via a connector
6
c.
When the rotor
6
rotates about a rotation axis Ax, the impact member
12
repeatedly hits an impact receiving face
20
of the auxiliary reciprocating member
14
a
. As shown in
FIG. 5
, the impact member
12
is arranged to come into hitting contact with the impact receiving face
20
at a marginal portion of the face
20
. (In
FIG. 5
, the hitting point is the left edge of the impact receiving face
20
.) In hitting the impact receiving face
20
, the impact member
12
will be rotated about a central axis Ay due to friction between the impact member
12
and the impact receiving face
20
.
By being repeatedly hit, the auxiliary reciprocating member
14
a
(and consequently the reciprocative implement
14
) is caused to reciprocate in a predetermined direction (vertical direction in FIG.
5
).
The above rotary impacting apparatus has been found disadvantageous in the following point.
When the impact member
12
hits the impact receiving face
20
at the above-mentioned marginal portion, a rotating force M may be applied to the auxiliary reciprocating member
14
a
, as shown in FIG.
5
. In such an instance, the auxiliary reciprocating member
14
a
will unfavorably be slanted in the housing
5
, thereby failing to provide smooth reciprocative movement or even becoming stuck in the housing
5
.
There may be several solutions to the above problems. One of them may be to lower the top dead center of the auxiliary reciprocating member
14
a
, so that the impact member
12
hits the auxiliary oscillating member
14
a
at an inner portion of the impact receiving face
20
. Another solution may be increasing the diameter of the auxiliary oscillating member
14
a.
However, the first solution is disadvantageous because the lowered auxiliary reciprocating member
14
a
fails to receive a sufficiently great impacting force from the impact member
12
. The second solution is also disadvantageous because the overall size and weight of the rotary impacting apparatus will unduly be increased.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention is to provide a rotary impacting apparatus which overcomes the above-described problems.
According to the present invention, there is provided a rotary impacting apparatus comprising:
a housing;
a rotor rotatably accommodated in the housing;
a driving source for rotating the rotor about a rotation axis;
a reciprocative implement reciprocatively held by the housing; and
an impact member eccentrically held by the rotor, the impact member exerting an impacting force for pressing the main reciprocative implement when the main reciprocative implement is advanced relative to the rotation axis;
characterised in that the reciprocative implement is provided with a diametrically smaller portion and a diametrically greater portion connected to the diametrically smaller portion.
With such an arrangement, it is possible to cause the main reciprocative implement to reciprocate smoothly (i.e., without being stuck) in the housing.
According to a preferred embodiment, the diametrically smaller portion is provided with an impact receiving face at which the impact member hits the main reciprocative implement. The impact receiving face may be arranged in parallel to the rotation axis.
Advantageously, the main reciprocative implement may be formed with a shock absorbing bore which is open at the impact receiving face.
In the preferred embodiment, the impact member has a columnar configuration.
The rotor may be formed with retaining holes for loosely retaining the impact member.
Preferably, the rotary impacting apparatus may further comprise an auxiliary reciprocating member reciprocatively held by the housing for transmitting an impacting force from the impact member to the main reciprocative implement when the main reciprocative implement is advanced relative to the rotation axis by a predetermined distance.
The auxiliary reciprocating member may be provided with a diametrically smaller portion and a diametrically greater portion connected to the diametrically smaller portion.
Preferably, the rotor may comprise a pair of flanges, a connector for connecting the flanges, and shafts projecting oppositely from the flanges. The shafts may be supported by the housing via needle bearings.
Preferably, the diametrically smaller portion may have a diameter which is smaller than a distance between the paired flanges.
Other objects, features and advantages of the present invention will become clearer from the detailed description of the preferred embodiment given below with reference to the accompanying drawings.
REFERENCES:
patent: 2079909 (1937-05-01), Jackson
patent: 2226559 (1940-12-01), Groom
patent: 2888246 (1959-05-01), Sieber
patent: 3127941 (1964-04-01), Sieber
patent: 3160217 (1964-12-01), Raihle
patent: 4601351 (1986-07-01), Hartwig et al.
patent: 5002134 (1991-03-01), Yamada
patent: 5048618 (1991-09-01), Lagne
patent: 5488997 (1996-02-01), Yamada
Bednarek Michael D.
Calve Jim
Pittman Shaw
Vo Peter
Yamada Machinery Industrial Co., Ltd.
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