Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
(TITLE OF THE INVENTION]
BARREL-POLISHING APPARATUS AND BARREL-POLISHING
METHOD
(FIELD OF THE INVENTION]
This invention relates to a barrel-polishing apparatus and a barrel-
polishing method.
(PRIOR ART]
(FIRST PRIOR ART AND SHORTCOMINGS THEREOF)
In conventional barrel-polishing apparatuses, it is a usual practice that
a workpiece is polished while flowing polishing mediums or while vibrating
a workpiece in stationary polishing mediums.
However, because of the reasons that the polishing mediums tend to
bulge over the workpiece due to flow of the polishing mediums in the former
polishing apparatus and due to flow of the polishing mediums caused by
vibrations of the workpiece in the latter polishing apparatus, a surface
pressure of the polishing mediums applicable to the workpiece is readily
reduced to discourage the enhancement of the polishing efficiency.
(SECOND PRIOR ART AND SHORTCOMINGS THEREOF)
Conventionally, there is known a typical method for polishing a
workpiece. In this method, a workpiece is placed in polishing mediums such
that an upper end side of a surface-to-be-polished of the workpiece is slanted
forwardly and the workpiece is polished by rotating the workpiece in a
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circumferential direction while flowing the polishing mediums relative to the
workpiece.
However this conventional barrel-polishing method has such
shortcomings that in case the workpiece has a hole around its axis, the
polishing mediums readily pass through the hole when they flow along the
workpiece and therefore, they hardly stay at the axial portion of the
workpiece, with the result that the axial portion of the workpiece is left
unpolished.
(THIRD PRIOR ART AND SHORTCOMINGS THEREOF)
In the conventional barrel-polishing apparatus, it is a usual practice
that a workpiece is polished while flowing the polishing mediums.
However, this conventional barrel-polishing apparatus has such
shortcomings that since the entire polishing mediums must be flowed in
order to flow the polishing mediums, the apparatus itself inevitably becomes
large scale.
(FOURTH PRIOR ART AND SHORTCOMINGS THEREOF)
If the workpiece is polished while rotating the workpiece in the
polishing mediums, the polishing mediums are worn. Therefore, in the
conventional apparatus, when the aggregate of polishing mediums has been
partly worn, the workpiece is moved in the polishing medium bath in an
effort to find a non-worn part of the polishing mediums and dipped in the
non-worn part of the polishing mediums. By keep doing so in the polishing
operation, a certain polishing effect can be obtained.
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However, in such a conventional polishing apparatus, since the partial
wear of the aggregate of polishing mediums is determined based on the
perception or experience of the operator, much labor is required. In addition,
since the result of determination is different depending on each operator, a
constant polishing effect is difficult to obtain in an efficient manner.
(OBJECTS OF THE INVENTION)
It is the first object of the present invention to provide, in order to
obviate the shortcomings inherent in the first prior art, a barrel-polishing
apparatus having flowing polishing mediums, wherein a pressure level of
polishing mediums applicable to a workpiece is maintained to a
predetermined value or larger by preventing the polishing mediums from
bulging, thereby enhancing the polishing efficiency of the barrel-polishing
operation (hereinafter referred to the "first and second inventions").
It is the second object of the present invention to provide, in order to
obviate the shortcomings inherent in the second prior art, a barrel-polishing
method, wherein polishing mediums are primarily stayed at an axial portion
of the workpiece so that a peripheral edge portion and the axial portion of
the circumferentially rotating workpiece can be polished efficiently and
positively (hereinafter referred to the "third to fifth inventions").
It is the third object of the present invention to provide, in order to
obviate the shortcomings inherent in the third prior art, a barrel-polishing
apparatus, which is simple in structure and easy in maintenance (hereinafter
referred to the "sixth and seventh inventions")
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It is the fourth object of the present invention to provide, in order to
obviate the shortcomings inherent in the fourth prior art, a barrel-polishing
apparatus, wherein a constant polishing effect can normally be obtained
efficiently and automatically even in case an aggregate of the polishing
mediums is partly worn (hereinafter referred to the "eighth invention").
(CONSTRUCTION OF THE INVENTION AND OPERATION AND
EFFECTS THEREOF)
A barrel-polishing apparatus according to the first invention
comprises a polishing medium bath with polishing mediums received therein,
a base, an arm mounted on the base, and a workpiece attachment device
mounted on a distal end portion of the arm and adapted to attach a
workpiece to the arm, wherein the polishing mediums are caused to flow
within the polishing medium bath by appropriate means and a pressing plate
for pressing the polishing mediums is mounted on the polishing medium
bath. Accordingly, since the polishing mediums are prevented from bulging
by this pressing plate, a pressure level of the polishing mediums applicable
to the workpiece can easily be maintained to a predetermined value or larger
in the barrel-polishing apparatus having flowing polishing mediums. Thus,
with use of this barrel-polishing apparatus, the polishing efficiency of the
barrel-polishing operation can easily be enhanced in the barrel-polishing
apparatus having flowing polishing mediums.
Also, as in the barrel-polishing apparatus according to the second
invention, if there are further employed vibration means for vibrating the
arm and a pressing plate for pressing the polishing mediums, mounted on the
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polishing medium bath, the polishing mediums are prevented from bulging
by this pressing plate. Accordingly, a pressure level of the polishing
mediums applicable to the workpiece can easily be maintained to a
predetermined value or larger in the barrel-polishing apparatus having a
vibrating workpiece. Thus, with use of this barrel-polishing apparatus, the
polishing efficiency of the barrel-polishing operation can easily be enhanced
in the barrel-polishing apparatus having a vibrating workpiece. If the
pressing plate is fixed to the base and the polishing medium bath is moved
reciprocally in a direction of the work attachment device by reciprocal
means, or if the pressing plate is fixed to the base and the pressing plate is
pressed in a direction of the polishing medium bath by pressing means, a
pressure of the pressing plate applicable to the polishing mediums can be
adjusted. Accordingly, a surface pressure of the polishing mediums
applicable to the workpiece can be adjusted appropriately.
Also, if the pressing plate is divided into a plurality of auxiliary
pressing plates and a pressing state of each of the auxiliary pressing plates
is
adjustable, a surface pressure of the polishing mediums applicable to a
surface-to-be-polished of a single workpiece can partly be adjusted.
Also, if the arm is swung about the base with respect to an inner wall
surface or an inner bottom wall surface of the polishing medium bath by
swing means such that the arm can be fixed at an appropriate location, the
surface pressure of the polishing mediums applicable to the workpiece can
be adjusted by varying the flow rate of the polishing mediums relative to the
workpiece.
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Also, if the arm is axially reciprocally moved by reciprocal means so
that the arm can be fixed at an appropriate location, the depth of the
workpiece with respect to the polishing mediums can be adjusted. Thus, the
surface pressure of the polishing mediums applicable to the workpiece can
be adjusted.
Also, a barrel-polishing apparatus according to the third invention
comprises a polishing medium bath with polishing mediums received therein,
a base, an arm mounted on the base, a workpiece attachment device mounted
on a distal end portion of the arm and adapted to attach a workpiece to the
arm, and a pressing plate mounted on the polishing medium bath and
adapted to press the polishing mediums, the polishing mediums being
flowed relative to the workpiece within the polishing medium bath, wherein
the pressing plate is disposed at an upper portion of the workpiece with an
appropriate space therebetween. Accordingly, since the polishing mediums
are prevented from bulging at its area above the workpiece by the pressing
plate, the surface pressure of the polishing mediums applicable to the
workpiece can be maintained at a level of a predetermined value or larger.
Thus, with use of this barrel-polishing apparatus, the polishing efficiency of
the barrel-polishing operation can easily be enhanced in the barrel-polishing
apparatus having flowing polishing mediums.
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Also, if, in this barrel-polishing apparatus, a guide plate is connected to
that end edge of the pressing plate located on an upstream side of the
polishing
mediums, and the guide plate is slanted towards the upstream side of the
polishing mediums in an opposite direction to the workpiece, the polishing
mediums can easily be gathered to the inner side of the pressing plate.
If, in this barrel-polishing apparatus, the pressing plate is fixed to the
base
and the polishing medium bath is reciprocally moved in a direction of the
workpiece attachment device by reciprocal means, or if the pressing plate is
mounted on the base and the pressing plate is pressed in a direction of the
polishing medium bath by pressing means, the pressure of the pressing plate
applicable to the polishing mediums can be adjusted. Thus, the surface
pressure
of the polishing mediums applicable to the workplace can appropriately be
adjusted.
Also, a barrel-polishing apparatus according to the fourth invention
comprises a polishing medium bath with polishing mediums received therein, a
base, an arm mounted on the base, a workplace attachment device mounted on a
distal end portion of the arm and adapted to attach a warkpiece to the arm,
and a
pressing plate mounted on the polishing medium bath and adapted to press the
polishing mediums, the polishing mediums being flowed relative to the
workplace
within the polishing medium bath, wherein the pressing plate is disposed at an
upper portion of the workplace with an appropriate space therebetween, and a
baffle plate is connected to a distal end side of the 'pressing plate in such
a
manner as to cover the workplace. Accordingly, the polishing mediums collided
against and raised along the surface-ta-be-polished of the workplace invade
into
a space surrounded by the pressing plate and the baffle plate and causes a
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turbulent flow involving the vicinity of the surface-to-be-polished of the
workpiece.
Accordingly, the polishing efficiency with respect to the workpiece is
enhanced.
Also, a barrel-polishing apparatus according to the sixth invention
comprises a polishing medium bath with polishing mediums received therein, a
base, rotational drive means mounted on the base, a rotary shaft mounted on
the
rotational drive means, and a workpiece attachment device mounted on a distal
end portion of the rotary shaft and adapted to attach a workpiece to the
rotary
shaft, wherein the barrel-polishing apparatus further comprises vibration
means,
and the rotary shaft is circularly vibrated by the vibration means along a
plane
including an axis of the rotary shaft, Accordingly, the polishing mediums can
be
moved into and out of the recess of the workpiece even in the state that the
polishing mediums are stopped. Therefore, with use of this barrel-polishing
apparatus, it becomes only needed to vibrate the rotary shaft instead of
flowing
the polishing mediums. Thus, the polishing apparatus itself is simplified in
structure and its maintenance becomes easy.
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As shown in a barrel-polishing apparatus according to the seventh
invention, instead of vibrating circularly, the rotary shaft may be vibrated
forwardly and backwardly, leftwardly and rightwardly.
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Also, if a slide plate is mounted on the base such that the slide plate is
reciprocally moved in a direction of the polishing medium bath by reciprocal
means and the rotational drive means is mounted on the slide plate, the
rotary shaft and thus the workpiece can be vibrated circularly, or forwardly
and backwardly, and leftwardly and rightwardly. Since the polishing
mediums can be more easily moved into and out of the recess of the
workpiece, the polishing efficiency with respect to the workpiece is more
enhanced.
Also, a barrel-polishing apparatus according to the eighth invention
comprises a polishing medium bath with polishing mediums received therein,
a base, a slide plate mounted on the base such that the slide plate is
reciprocally moved in a direction of the polishing medium bath by reciprocal
means, an electrically-operated rotational drive means mounted on the slide
plate, a rotary shaft mounted on the electrically-operated rotational drive
means and extending in a direction of reciprocal movement of the slide plate,
and a workpiece attachment device mounted on a distal end portion of the
rotary shaft and adapted to attach a workpiece to the rotary shaft, wherein
the barrel-polishing apparatus further comprises a control unit for
controlling
a reciprocal movement of the reciprocal means by detecting an electric
current supplied to the electrically-operated rotational drive means.
Accordingly, when the rotary torque of the workpiece in the polishing
mediums is reduced to reduce the electric current supplied to the electrically-
operated rotational drive means, the workpiece can be moved in the
polishing mediums in such a manner as to increase the rotary torque. On the
other hand, when the rotary torque of the workpiece in the polishing
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mediums is increased to increase the electric current supplied to the
electrically-operated rotational drive means, the workpiece can be moved in
the polishing mediums in such a manner as to reduce the rotary torque.
Therefore, with use of this barrel-polishing apparatus, a constant rotary
torque can normally be obtained even if the aggregate of polishing mediums
is partly worn. Thus, a constant polishing effect can be obtained efficiently
and automatically.
If the slide plate is moved towards the polishing medium bath when
the electric current supplied to the electrically-operated rotational drive
means is smaller than a reference electric current and the slide plate is
moved away from the polishing medium bath when the electric current
supplied to the electrically-operated rotational drive means is larger than
the
reference electric current, the workpiece can easily be moved in the less-
worn polishing mediums when the rotary torque is reduced and the
workpiece can easily be moved in the more-worn polishing mediums when
the rotary torque is increased.
Also, if the base is slanted downwardly towards the polishing medium
bath, the workpiece can easily be moved reciprocally with respect to the
polishing medium bath.
(BRIEF DESCRIPTION OF THE DRAWINGS)
Figs. 1 to 9 show embodiments of the first and second inventions
wherein:
Fig. 1 is a perspective view of a barrel-polishing apparatus according
to the present invention;
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Fig. 2 is a perspective view of the barrel-polishing apparatus with a
workpiece removably attached thereto;
Fig. 3 is a sectional view taken on line III-III of Fig. 1;
Fig. 4 is an illustration when viewed in a direction as indicated by an
arrow IV of Fig. 3;
Fig. 5 is an explanatory view showing a rotary mechanism of an
inverting plate employed in the barrel-polishing apparatus;
Fig. 6 is an illustration for explaining the location of a pressing plate
and a flowing direction of a polishing medium;
Fig. 7 is another illustration for explaining the location of a pressing
plate and a flowing direction of a polishing medium;
Fig. 8 is another embodiment in which the pressing force of the
pressing plate is adjustable; and
Fig. 9 is a view of another embodiment corresponding to Fig. 3.
Figs. 10 to 17 show embodiments of the third to fifth inventions,
wherein:
Fig. 10 is a perspective view of a barrel-polishing apparatus according
to the present invention;
Fig. 11 is a perspective view of the barrel-polishing apparatus with a
workpiece removably attached thereto;
Fig. 12 is a sectional view taken on line X-X of Fig. 10;
Fig. 13 is a perspective view of a pressing plate of Fig. 12;
Fig. 14 is a perspective view of another embodiment of the pressing
plate;
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Fig. 15 is an illustration far explaining the location of the pressing plate
with respect to a workpisce;
Fig: 16 is an illustration of another embodiment of the pressing plate
corresponding to Fig. 14; and
Fig. 17 is a sectional view taken on fine XVff--XVII of Fig. 16.
Figs. 18 and 19 show embodiments of the sixth and seventh inventions,
wherein:
Fig. 18 is a front view of a barrel-polishing apparatus according to the
present invention; and
Fig. 19 is a sectional view taken on line XIX--XIX of Fig. 18.
Fig. 20 is a sectional view of a barrel-polishing apparatus, showing an
embodiment of the eighth invention.
[EMBODIMENTS]
(EMBODIMENTS OF THE FIRST AND SECOND INVENTIONS)
In Figs. 1 and 2, reference character B denotes a barrel-polishing
apparatus and reference numeral 10 denotes its base. Reference numeral 20
denotes a polishing medium bath which is placed on the base 10. The polishing
medium bath 20 is of a cylindrical configuration. This polishing medium bath
20
can be rotated circumferentially about an axis by suitable driving means.
Reference numeral 21 denotes polishing mediums which are received in the
polishing medium bath 20. Those polishing mediums 21 are also rotated
circumferentially as the polishing medium bath 20 rotates circumferentially.
Any
mediums such as ceramics which are usually used, can be used as the polishing
mediums 21. The polishing method may be a wet polishing or a dry polishing.
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Reference numeral 22 denotes an upper end opening of the polishing
medium bath 20. Through this upper end opening 22, a workpiece (vehicle wheel
made of aluminum in this embodiment) W is dipped in the polishing mediums 21.
Reference numeral 11 denotes a support frame erected from the base 10.
This support frame 11 extends approximately so far as an upper end of the
polishing medium bath 20.
Reference numeral 30 denotes an inverting plate. This inverting plate 30 is
placed on the support frame through a rotary shaft 31. The inverting plate 30
rotates within a range of approximately 180 degrees (from the state of Fig. 1
to
the state of Fig. 2) as the rotary shaft 31 rotates. Also, as shown in Fig. 5,
a first
drive motor 32 is disposed on the support frame 11. A rotational force of the
motor 32 is transmitted from a pulley 33 to a pulley 35 of the rotary shaft 31
through a V-belt 34 in its decelerated state, so that the inverting plate 30
can
reciprocally be inverted within a range of 180 degrees.
In Fig. 3, reference numeral 301 denotes a pivot pin applied to the
inverting plate 30 and partly projecting upwardly. The function of this pivot
pin
301 will be described hereinafter.
Reference numeral 36 denotes a tumable plate. This tumable plate 36 is
placed on an upper surtace of the inverting plate 30 in superimposed relation.
As
shown in Fig. 3, the turnable plate 36 has a through hole 361 (see Fig. 3).
The
pivot pin 301 is loosely fitted in the through hole 361. This makes it
possible for
the tumable plate 36 to tum about the pivot pin 301. Reference numeral 362
denotes a worm wheel. This worm wheel 362 is mounted on a projected portion of
the pivot pin 301.
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Referring again to Fig. 3, reference numeral 363 denotes a fourth drive
motor. This fourth drive motor 363 is fixedly mounted on the turnable plate
36. As
shown in Figs. 3 and 4, reference numeral 364 denotes a worm gear connected
to a rotational pin of the fourth drive motor 363. Since the worm gear 364 is
in
engagement with the worm wheel 362, the tumable plate 36 on which the fourth
drive motor 363 is fixedly mounted, can turn about the pivot pin 301 when the
fourth drive motor 363 is rotated. It should be noted that although the worm
gear
364 and the worm wheel 362 correspond to the "swing means" of the first and
second inventions, the swing means of the present invention is by no means
limited to the aforementioned worm gear 364 and worm wheel 362 but it inGudes
all existing conventional swing means.
Reference numeral 41 denotes one pair of attachment devices which are
disposed on opposite rear end portions of the tumable plate 36. The attachment
devices 41 extend upwardly in generally parallel relation. Reference numeral
40
denotes a support bed. This support bed 40 is turnably mounted on distal end
portions of the attachment devices 41 through pins 42. The support bed 40 is
normally held in its forwardly slanted state (the forward end side of a
workpiece
support arm 60 as later described is herein referred the forward direction).
Reference 43 denotes a piston cylinder mechanism disposed between the
support bed 40 and the turnable plate 36. This piston cylinder mechanism 43
comprises a piston rod 431 disposed on the support bed 40 and a cylinder 432
disposed on the turnable plate 36. The piston cylinder mechanism 43 is
reciprocally operated by air pressure or hydraulic pressure, thereby enabling
to
swing the support bed 40 relative to the turnable bed 36 such that the support
bed 40 is stopped in any desired place.
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As shown in Fig. 3, a slider 50 is reciprocally mavably disposed on a lower
surface of the support bed 40 along the slanting direction of the support bed
40.
This slider 50 can reciprocally move relative to the support bed 40 by a bolt
nut
mechanism (this bolt nut mechanism corresponds to the "'reciprocal means" of
the
first and second inventions) 51. Reference numeral 511 denotes a bolt portion
of
the bolt nut mechanism 51 disposed on the lower surface of the support bed 40
and reference numeral 512 denotes nut portions of the bolt nut mechanism 51
disposed on the slider 50. When a second drive motor 52 is driven to tum the
bolt
portion 511, the nut portion 511 and thus the slider 50 are reciprocally moved
along an axial direction of the bolt portion 511 in response to the threading
motion of the bolt potion 511. The aforementioned "reciprocal means" includes
not only the bolt nut mechanism 51 but also all existing conventional
reciprocal
means.
Reference numeral 55 denotes a motor installation chamber which is
defined in the slider 50. Reference numeral 521 denotes a through hole which
is
formed in a rear wall of the motor installation chamber 55, The functions of
the
motor installation chamber 55 and the through hole 521 will be described
hereinafter.
Reference numeral 61 denotes a third drive motor. This third drive motor
61 is fitted to the motor installation chamber 55 through a resilient material
(spring, rubber, etc.). Owing to this feature, the third drive motor 61 can
swingingly move upwardly and downwardly, leftwardly and rightwardly in the
motor installation chamber 55.
Reference numeral 60 denotes a workpiece support arm. This workpiece
support arm 60 is connected to the third drive motor 61 in its rotational
force
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reduced state. A workpiece (aluminum vehicle wheel) W is removably attached to
a distal end of the workpiece support arm 60 through an air chuck and dipped
in
the polishing mediums 21 of the polishing medium bath 20. Thus, in response to
the rotation of the third drive motor 61, the workpiece support arm 60 rotates
about its own axis. It should be noted here that the workpiece support arm 60
can
also intermittently rotate normally and backwardly.
Reference numeral 53 denotes a fifth drive motor. This fifth drive motor 53
is disposed at a backward location in the motor installation chamber 55 of the
slider 50. This fifth drive motor 53 is connected to a rear end portion of the
third
drive motor 61 through a crank mechanism (this crank mechanism corresponds to
the "vibration means" of the first and second inventions) 54 to apply micro-
vibrations to the third drive motor 61. The crank mechanism 54 comprises a
crank
arm 541 connected to the fifth drive motor 53 and a crank rod 542 rackably
connected to the crank arm 541 and the third drive motor 61. Reference numeral
70 denotes a pressing plate integrally formed on the distal end of the support
bed
40. This pressing plate 70 is adapted to prevent the polishing mediums 21 from
bulging when the workpiece W is being polished in the polishing mediums 21.
In case the workpiece W is placed with its surface to be polished slanted
forwardly upwardly (see Fig. 6) with respect to the flowing direction (as
indicated
by an arrow A) of the polishing mediums 21, the pressing plate 70 is disposed
on
that place of the polishing mediums 21 located forwardly of the workpiece W
where the polishing mediums 21 are readily bulged. On the other band, in case
the workpiece W is placed with its surface to be polished slanted forwardly
downwardly (see Fig. 7) with respect to the flowing direction (as indicated by
an
arrow A) of the polishing mediums 21, the pressing plate 70 is disposed on
that
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place of the polishing mediums 21 located generally upwardly of the workpiece
W
where the polishing mediums 21 are readily bulged. In case of a workpiece W
having a so-called through hole (this through hole corresponds to the "window
portion" of the first and second inventions) 75 such as a vehiGe wheel having
a
window portion, the state of Fig. 7 is more preferred because the polishing
mediums 21 pass through the through hole 75 and the flow thereof becomes
smoother. As a consequence, the polishing effect is enhanced.
If, as indicated by an imaginary line, a support device 71 is mounted on the
support bed 40, the pressing plate 70 and the support bed 40 are separately
provided, and the pressing plate 70 is mounted on the support bed 40 through
piston cylinder mechanisms (the piston cylinder mechanisms correspond to the
"pressing means" of the first and second inventions) 73, the pressing force of
the
pressing plate 70 can be appropriately adjusted in accordance with the
operation
of the piston cylinder mechanisms 73. each piston cylinder mechanism 73
comprises a cylinder 731 and a piston rod 732 and is reciprocally moved by air
pressure or hydraulic pressure. Also, by dividing the pressing plate 70 into a
plurality of auxiliary pressing plates and adjusting a pressing state of each
of the
auxiliary pressing plates by the piston cylinder mechanism 73 or the like, the
surface pressure of the polishing mediums 21 applicable to the workpiece W can
partly be adjusted. Also, by forming a window or the like in the pressing
plate 70,
the surface pressure of the polishing medium 21 applicable to the workpiece W
can be adjusted. The pressing means includes not only this piston cylinder
mechanism 73 but also all existing conventional pressing means.
On the other hand, as shown in Fig. 8, by reciprocally moving the polishing
medium bath 20 towards an upper portion (opening 22 side) of the polishing
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medium bath 20 by an appropriate reciprocal means (piston cylinder mechanism,
or the like) 73 with the pressing plate 70 fixed, the surface pressure of the
polishing mediums 21 applicable to the workplace W can be adjusted.
Attaching/detaching operation of the workplace W in this polishing
apparatus will now be described briefly.
First, the first drive motor 32 is driven to rotate the rotary shaft 31 so
that
the inverting plate 30 is brought to an outer side of the polishing medium
bath 20
(see the state indicated by an imaginary line of Fig. 5). At that time, the
distal end
of the workplace support arm 60 is oriented slantwise upwardly. In that state,
the
operator fixedly attaches the vehicle wheel W to the distal end of the
workplace
support arm 60.
Thereafter, the first drive motor 32 is driven to rotate the rotary shaft 31
backwardly so that the inverting plate 30 is brought to an inner side of the
polishing medium bath 20 and then, the vehicle wheel W is dipped into the
flowing polishing mediums 21 in the polishing medium bath 20. After the
completion of polishing operation, the first drive motor 32 is driven to
rotate the
rotary shaft 31 so that the inverting plate 30 is brought to an outer side of
the
polishing medium bath 20. At that time, the distal end of the workplace
support
arm 60 is oriented slantwise upwardly. In that state, the operator detaches
the
vehicle wheel W from the workplace support arm 60 and fixedly attach the next
workplace.
Fig. 9 shows another embodiment in which the work support arm 60 is
mounted such that the surface-to-be-polished of the workplace W is in
generally
parallel relation to the bottom wall surface of the palishing medium bath 20.
One example of acceptable polishing mediums includes soft material in the
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form of particles, lumps, or the like, such as sponge, rubber, soft plastic,
etc. By
using one of those materials, the finish polishing can be performed
efficiently. It
should be noted that the polishing mediums of this type may be obtained by
coating a soft material on the surface of hard partiGes, hard lumps, or the
like.
After barrel polishing, the workpiece is then subjected to surtace treatment
such as coating, plating, alumiting, etc. This surface treatment may be any of
the
existing techniques usually put into practice.
(EMBODIMENTS OF THE THIRD TO FIFTH INVENTIONS)
Description of those portions in common with the first and second
inventions is omitted.
As shown in Figs. 10 and 11, the pressing plate 70 employed in this
embodiment comprises auxiliary plates 702 connected to opposite end edges of a
horizontal plate 701, thus exhibiting a generally horizontal U-shaped
configuration (namely, a configuration gradually open towards its distal end).
The
inner side surrounded by the horizontal plate 701 and one pair of the
auxiliary
plates 702 corresponds to the recess of the present invention. The pressing
plate
70 may exhibit a V-shaped configuration or a U-shaped configuration in
section.
The pressing plate 70 is placed such that the recess surrounds an upper
portion
of the workpiece W with an appropriate space therebetween (see Fig. 12). The
horizontal plate 701 may be placed in parallel relation to the relatively
flowing
direction, as indicated by an arrow A of Fig. 15, of the polishing mediums 21
so
that the forward of the workpiece W is spread, or it may be placed in parallel
with
the axis of the workpiece (vehicle wheel) W as indicated by an imaginary line
of
Fig. 15.
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Fig. 13 shows an improvement of the pressing plate 70 described above.
In the illustration, reference numeral 76 denotes a guide plate. As shown in
Fig.
13, the guide plate is formed in a fan-like shape which is widened toward an
end
thereof and has a surtace of partially conical ar pyramidal, thereby guiding
the
polishing mediums toward the end of the pressing plate. This guide plate 76 is
connected to that end edge of the pressing plate 70 located on the upstream
side
of the relative flow of the polishing mediums 21. The guide plate 76 is
slanted in
an opposite direction to the workpiece W towards the upstream of the relative
flow of the polishing medium 21. In other words, the guide plate 76 is
gradually
dilated towards the upstream of the relative flow of the polishing medium 21.
This
guide plate 76 may be designed such that its width is gradually reduced
towards
the opposite end edges (lower end edges of the auxiliary plates 702) of the
pressing plate 70 as indicated by an imaginary line of Fig. 13. In this way,
since
the aggregate of the polishing mediums 21 can be gradually reduced towards the
opposite end edges (lower end edges of the auxiliary plates 702) of the
pressing
plate 70, the surface pressure applicable to the entire workpiece W can be
adjusted so as to be uniform in relation to the depth of the polishing mediums
21.
Fig. 14 shows another example of an improved pressing plate 70. The
pressing plate 70 of this example exhibits a generally li-shaped configuration
in
section. If the pressing plate 70 is designed in this way, in case the
workpiece W
has a diso-like configuration such as a vehicle wheel or the like, a
predetermined
interval between the pressing plate 70 and the workpiece W can easily be
obtained. In Figs. 13 and 14, the arrow A shows the direction of the relative
flow
of the polishing mediums 21.
In the present invention, the expression "relative flow of the polishing
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mediums" refer to (1 ) the polishing mediums 21 flow while the workpiece W is
stationary, (2) the workpiece W is moved while the polishing mediums 21 are
stationary, and (3) the polishing mediums 21 ace moved in opposing relation.
Figs. 16 and 17 show another example in which a semi-dome like baffle
plate 79 is connected to a distal end side of the pressing plate 70. Owing to
this
arrangement, the polishing mediums 21 collided against and raised along the
surface-to-be-polished of the workpiece W invade into the inner side of the
baffle
plate 79 and cause a turbulent flow involving the vicinity of the surtace-to-
be-
polished of the workpiece W. This serves to enhance the polishing efficiency
with
respect to the workpiece W. It should be noted that the configuration of the
baffle
plate 79 is by no means limited to the semi-dome like configuration but it can
be
any one of numerous configurations which can prevent the flow of the polishing
mediums 21 and cause a turbulent flow.
The attaching/detaching operation of the workpiece W and the method to
cant' out the polishing operation in this polishing apparatus will now be
described
briefly.
First, the first drive motor 32 is driven to rotate the rotary shaft 31 so
that
the inverting plate 30 is brought to an outer side of the polishing medium
bath 20
(see the state indicated by an imaginary line of Fig. 5). At that time, the
distal end
of the workpiece support arm 60 is oriented slantwise upwardly. In that state,
the
operator fixedly attaches the vehicle wheel W to the distal end of the
workpiece
support arm 60.
Thereafter, the first drive motor 32 is driven to rotate the rotary shaft 31
backwardly so that the inverting plate 30 is brought to an inner side of the
polishing medium bath 20 and then, the vehicle wheel W is dipped into the
CA 02255501 2002-10-16
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flowing polishing mediums 21 in the polishing medium bath 20. At that time,
the
polishing mediums 21, which are prevented from escaping by the pressing plate
70, can rub the workpiece W.
The flowing of the polishing mediums 21 relative to the workpiece W is
reduced (or stopped) at the first or last stage of a polishing operation so
that the
polishing mediums 21 will primarily stay at the axial portion of the workpiece
W.
By doing so, the axial portion of the workpiece W can be polished efFciently
and
positively.
After the completion of polishing operation, the first drive motor 32 is
driven to rotate the rotary shaft 31 so that the inverting plate 30 is brought
to an
outer side of the polishing medium bath 20. At that time, the distal end of
the
workpiece support arm 60 is oriented slantwise upwardly. In that state, the
operator detaches the vehicle wheel W from the workpiece support arm 60 and
fixedly attach the next workpiece.
(EMBODIMENTS OF THE SIXTH AND SEVENTH INVENTIONS)
In Figs. 18 and 19, reference character B denotes a barrel-polishing
apparatus. This barrel-polishing apparatus B includes a cylindrical polishing
medium bath 20. Reference numerals 21 denote polishing mediums which are
received in the polishing medium bath 20. Any mediums such as ceramic
partiGes which are usually used, can be used as the polishing mediums 21. The
polishing method may be a wet polishing ar a dry polishing.
Reference numeral 22 denotes an upper end opening of the polishing
medium bath 20. Through this upper end opening 22, a workpiece (vehicle wheel
made of aluminum in this embodiment) W is dipped in the polishing mediums 21.
CA 02255501 2002-10-16
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On the other hand, reference numeral 11 denotes a support bed of the
barrel-polishing apparatus B and reference numeral 401 denotes a base (this
base corresponds to the "base" of the sixth and seventh inventions) swingably
mounted on this support bed 11. This base 401 is slanted downwardly in a
direction (as indicated by arrow D of Fig. 19) of the polishing medium bath
20.
This slanting angle can appropriately be adjusted. The base 401 can stop at an
appropriate angle. Reference numeral 551 denotes a geared engine mounted on
the base 401, and reference numeral 511 denotes a bolt member connected to
the geared engine 551. This bolt member 511 is rotatabiy supported by one pair
of bearings 80 such that it can rotate normally and backwardly about its axis
in
accordance with rotation of the geared engine 551. This bolt member 511 is
disposed along the slanted direction of the base 401. Reference numerals 81
denote guide members. The guide members 81 are disposed between the paired
bearings 80. Operation of the guide members 81 will be described hereinafter.
Reference numeral 50 denotes a slide plate, and reference numerals 512
denote nut members projecting from a lower surface of this slide plate 50. The
slide plate 50 is slidably fitted to the guide members 81 and the nut members
512
are threadingly engaged with the bolt member 511 of the base 401. Owing to
this
arrangement, the slide plate 50 can reciprocally slide in accordance with
rotation
of the bolt member 511. The bolt member 511, the nut member 512 and the
geared engine 551 correspond to the "reciprocal means" of the sixth and
seventh
inventions.
Reference numeral 82 denotes a shelf portion. This shelf portion 82 is
integral with a front end edge of the slide plate 50 and projects in a
perpendicular
direction with respect to the slide plate 50. Reference numeral 83 denotes a
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support plate which is mounted on the shelf portion 82 through springs 84.
This
support plate 83 can reciprocally move in the forward and backward directions
and swing leftwardly and rightwardly under the effects of the springs 84.
Reference numeral 61 denotes a rotational drive portion placed on the
support plate 83. This rotational drive portion 61 comprises an engine (AC or
DC
engine) and a reduction gear unit. The rotational drive portion 61 can provide
a
rotary motion through a rotary shaft 60. The rotary shaft 60 extends along the
axis of the bolt member 511, i.e., in the slanting direction of the base 40.
Reference numeral 85 denotes an engine placed on the support plate 83.
A rotary shaft of this engine 85 is faced with the rotary shaft 60 of the
rotational
drive portion 61. Reference numeral 86 denotes a balance weight mounted on
the rotary shaft of the engine 85. Since the balance weight 86 pertorms a
circular
motion (see the imaginary line of Fig. 19) when the engine 85 rotates, the
support
plate 83 and thus, the rotary shaft 60 are vibrated circularly or forwardly
and
backwardly, and leftwardly and rightwardly along a surface including the axis
of
the rotary shaft 60. The engine 85, the balance weight 86, the support plate
83
and the spring 84 correspond to the "vibration means" of the sixth and seventh
inventions. The engine 85 may be provided with a reduction gear unit.
The workpiece (aluminum vehicle wheel) W is attached to a distal end of
the rotary shaft 60 through a work attachment device (an air chuck) 87 and
dipped in the polishing mediums 21 of the polishing medium bath 20. Then, the
rotational drive portion 61 is actuated to rotate the rotary shaft 60 and thus
the
workpiece W in the polishing mediums 21. At the same time, the engine 85 is
actuated to cause the rotary shaft 60 to vibrate circularly or forwardly and
backwardly, and leftwardly and rightwardly along a plane inGuding its axis. By
CA 02255501 2002-10-16
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doing so, the workpiece W can be barrel polished. At that time, since the
workpiece W also vibrates circularly or forwardly and backwardly, and
leftwardly
and rightwardly, the polishing mediums 21 are positively brought into and out
of
the recesses 88. As a consequence, the recesses 88 can also be polished
positively.
In this embodiment, only one example of the vibration means is shown. It
should be noted, however, that the vibration means of the present invention is
by
no means limited to this example but it also inGudes all existing conventional
vibration means.
(EIGHTH EMBODIMENT)
Description of those portions in common with the embodiments of the sixth
and seventh inventions is omitted.
Reference numeral 61 denotes a rotational drive portion (this rotational
drive portion corresponds to the "electrically-operated rotary means" of the
eighth
invention). The rotational drive portion 61 is mounted on the slide plate 50.
The
rotational drive portion 61 comprises an engine (AC or DC engine) and a
reduction gear unit. The rotational drive portion 61 can provide a circular
motion
through the rotary shaft 60. The rotary shaft 60 extends along the axis of the
bolt
member 511, i.e., in the slanting direction of the base 40.
The engine (AC or DC) of the rotational drive portion 61 is driven by a
power source 92. At that time, the electric current supplied to the engine is
measured by a current detector means 93. The result of measurement thus
obtained is sent to a control unit 94 where the result of measurement is
compared
with a preset value (this preset value corresponds to the "reference electric
CA 02255501 2002-10-16
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current" of the eighth invention) and then used as a base for control the
operation
of the geared engine 52.
The polishing mediums 21 of the polishing medium bath 20 are, in general,
less worn towards the lower layer thereof and more worn towards the upper
layer
because of frequency of use.
The preset value of the control portion 94 is preliminarily established as a
current value to be supplied to the engine in relation to a rotary torque
required
by the engine of the rotational drive portion 60 in consideration of the size
of the
workplace W as an object to be polished, configuration of the workpiece W, a
required degree of polishing, etc. This preset value is determined based on
experience.
Operation of this apparatus will now be described.
First, the preset value is determined in the control portion 94 based on the
size, the configuration, etc. of the workplace W.
In that condition, the power source for the engine of the rotational drive
portion 61 is turned on in the state that the workplace W is dipped in the
polishing
mediums 21 of the polishing medium bath 20. Then, the rotational drive portion
61 is actuated and the workplace W is polished in the polishing mediums 21. At
that time, the electric current supplied to the engine of the rotational drive
portion
61 is measured by the electric current detector means 93. Then, the result of
measurement thus obtained is sent to the control unit 94 where the result of
measurement is compared with the preset value. When the result of
measurement is larger than the preset value, i.e., when the rotary torque is
large,
the geared engine 52 is actuated to rotate the bolt portion 511, so that the
slide
plate 50 and thus the rotational drive portion 61 is retracted to bring the
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workpiece W to an upper layer portion of the polishing mediums 21 and stop it
at
a position where the value of measurement of the electric current is equal to
the
preset value. On the other hand, when the value of measurement is smaller than
the preset value, i.e., when the rotary torque is small, the geared engine 52
is
actuated to rotate the bolt member 511 backwardly to move the,slide plate 50
and
thus, the rotational drive portion 61 forwardly, so that the workpiece W is
brought
to a lower layer portion of the polishing mediums 21 and stop it at a position
where the value of measurement of the electric current is equal to the preset
value.
