Note: Descriptions are shown in the official language in which they were submitted.
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KNOCKOUT DEVICE FOR A PRESS MACHINE HAVING
A SLIDE GUIDE DEVICE
BACKGROUND OF THE INVENTION
The present invention relates to a knockout device for a press machine,
and especially a knockout device for removing a press worked product from
within a die of a press machine having a slide guide device having a self-
aligning
mechanism. Such a press machine is especially suitable for high precision
molding of parts, particularly cold extrusion parts, punched parts, drawn
parts,
and the like.
Innovations to make the sliding of the slide and guide post smooth, to
ensure the product precision of the press products, or to absorb unbalanced
loads on a slide and heighten the dynamic precision, are constantly being
conducted for press machines and the like. Currently, however, a satisfactory
mechanism has yet to be achieved.
In Japanese Laid-Open Patent Publication Number 8-206895, a slide
guide device for a press machine has a plurality of guide posts provided at
appointed locations of a slide. The plurality of guide posts supports a
vertically
oriented base shaft part in a freely rotating manner. An eccentric shaft part,
which is unbalanced by a constant eccentricity amount with respect to this
base
shaft part, extends downward from the plurality of guide posts. A plurality of
guide blocks are separately attached opposite each of the guide posts. The
plurality of guide blocks guides the eccentric part in the vertical direction
in a
freely sliding manner. The guide blocks are disposed so that the direction of
eccentricity of the eccentric shaft part with respect to the base shaft part
of
each of the guide posts has an angle relationship with respect to the thermal
expansion direotion of the slide so that, while the center of the slide is
maintained at a constant position, the slide is guided in the vertical
direction in
a freely moving state. A slide is guided in a freely moving state in the
vertical
direction by the plurality of guide posts.
In Japanese Laid-Open Patent Number 8-174294, a slide gib is multiply
divided in the shaft line direction from the center of a long material having
a
cylindrical central hole. In addition, the inner perimeter surface of the
central
hole is made to be a sliding surface. The liner is multiply divided in the
shaft
line direction from the center of a cylinder. The outer perimeter surface of
the
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cylinder is made to be a sliding surface. The dynamic precision is improved by
minimizing the mis-alignment of each of the upright and the slide.
However, with the former slide guide device, the displacement of the
slide is absorbed by making the center of the base shaft part of the guide
post
capable of moving horizontally with respect to the center of the eccentric
shaft
part in the direction of displacement resulting from thermal expansion. When
an eccentric load acts on the slide, the bending stress on the eccentric shaft
parts at the four corners is unavoidable. Because of the action of a twisting
torque, a smooth vertical motion of the slide can not be anticipated, and,
therefore, it is difficult to bring out the precision of the die.
The latter example is constructed so that the slide gib and the liner make
contact in the radial direction at the are surface. However, because it is a
member which is long in the shaft direction, and there is a line contact or a
surface contact in the shaft direction, even if the eccentric load in the
rotation
direction is absorbed, absorbing the eccentric load in the shaft direction
remains
difficult.
A knockout device for a press machine is a necessary mechanism for
removing a product which has been worked in a press. Knockout devices are
widely used irrespective of the type of press.
A conventional construction for a knockout device is described in
Japanese Laid Open Patent Publication Number 6= 126368. In this embodiment,
a lower holder, anchoring a die, is affixed to a top surface of a bolster. A
through hole is formed in the center of the lower holder and bolster. A
mandrel
transfer pin is inserted through this hole. The knockout pin moves vertically
due
to a roller which abuts against the lower end of this pin. Furthermore, this
roller
is linked with a cam mechanism through a third link mechanism.
In Japanese Laid Open Patent Publication Number 9-285830, a knockout
device is disclosed which has a knockout pin guided by a case and a taper
block.
However, with the former construction, the roller pivots along the path
drawn by the end of a pivoting link member having one end as the support
point. Therefore, the contact point with the knockout pin moves with the
position of the roller. In addition, the knockout pin also moves, and, as a
result,
it is difficult to always push up perpendicularly. Problems arise in which
this
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becomes mechanical vibration or becomes a sliding load and requires a large
amount of energy for the motion.
With the latter, the roller still moves along the movement pathway of the
knockout lover as in the former example. The roller does not have a
construction wherein the center of the knockout pin is always being pushed up
at the time of knockout. Therefore, as a matter of course, a bending stress
acts
on the knockout pin, and a smooth motion with the case is not achieved. The
same problems as described above are also a concern.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a knockout device for
a low noise, energy conserving press machine wherein knockout requires a small
amount of energy and operation is conducted under an always stable knockout
load.
The Applicant's co-pending Canadian patent application number
2,304,429 discloses and claims a press machine and a slide guide therefor in
which there is provided a middle liner of a slide guide device having a
spherical
shaped side which fits into a sliding gib attached to a slide. The middle
liner
slides along a fixed gib first and second linear surfaces at an angle with
each
other. Self-alignment and smooth movement of the slide is achieved even when
an eccentric load acts on the slide. A machine press equipped with such a
slide
guide device has excellent eccentric load resistance and high working
precision.
According to the present invention, there is provided a knockout device
for a press machine having a slider with a die attachment surface, comprising:
a lower ho[der opposite said die attachment surface; a knockout pin passing
through said lower holder; a knockout block which knocks out said knockout
pin; at least first and second guide rails disposed at opposite sides of said
knockout block; means for moving said knockout block along said at least first
and second guide rails; and a plurality of middle liners, having at least one
spherical surface, between a side surface of said knockout block and said at
least first and second guide rails.
For example, a plurality of middle liners, having at least one surface as a
spherical surface, are disposed between a side surface of the knockout block
and a pair of guide rails, which is disposed and affixed opposite the block
side
surface. The middle liners guide the knockout block.
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Preferably, a knockout device is provided wherein the guide rail is tubular
or cylindrical and is in surface contact with the other surface of the middle
liner.
More preferably, a knockout device is provided wherein the guide rails are
triangular poles and in two surface contact with two surfaces of the middle
liner.
Even more preferably, a knockout device is provided wherein the lower
end of the knockout block is pivotably connected via an eccentric pivoting
mechanism to one end of a knockout lever whose other end is connected to a
motion source which moves vertically.
The knockout device may have an eccentric pivoting mechanism pivotably
attached at a first end to a lower end of said knockout block and a second,
opposite end of said eccentric pivoting mechanism attached to a motion source,
wherein motion of said motion source provides said means for moving said
knockout device.
The motion source may comprise:
a double acting double rod type hydraulic cylinder;
a variable hydraulic pump driven by a motor, said variable hydraulic pump
providing pressurized oil to said hydraulic cylinder for operating said
hydraulic
cylinder; and
a fly wheel provided between said hydraulic pump and said motor for
storing rotational energy supplied by said motor and supplying the stored
rotational energy to said hydraulic pump;
wherein said fly wheel has a clutch for controlling the supplying of stored
rotational energy to said hydraulic pump, said clutch being operative to open
and close by an external control.
In a preferred embodiment, the knockout device has a lower holder
disposed opposite a die attachment surface of a slide which moves vertically.
A knockout pin passes through this lower holder. A knockout block knocks out
the knockout pin. A plurality of middle liners are disposed between a side
surface of the knockout block and a pair of guide rails which are disposed and
affixed opposite this block side surface. The lower end of the knockout block
connects in a pivotable manner via an eccentric pivoting mechanism to one end
of a knockout lever whose other end is connected to a motion source which
moves vertically. The motion source is a double acting double rod hydraulic
cylinder. This cylinder, by a variable hydraulic pump which is driven by a
motor,
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compneses and controls oil, which is supplied from a hydrauiic tank.
Rotationai energy
is stored between the hydraulic pump and the motor. A fly wheel is provided
via a clutch
which is opened and closed by an external controi.
Preferably, a knockout device is provided wherein, after the rotational energy
of
5 the motor is stoned in the fly wheel, the rotational energy is supplied to
the hydraulic
pump via the clutch which opens and cioses by an external control.
More preferably, a knockout device is provided wherein when the oil pressure
inside the hydraulic supply circuit exceeds a pn:set standard value, a
pressure control
valve operates and oil is guided to the tank.
The above, and other objects, features and advantages of the present invention
will beoome apparent from the following description read in conjunction with
the
accompenying drawings, in which like reference numerals designate the same
elements.
BRIEF DESCRIPTION OF THE DRAWINGS 15 Fig. I is a longitudinal front view of a
screw type press machine;
Fig. 2 is a longitudinal side view of the screw type press machine of Fig. 1.
Fig. 3 is a cross-section along line A-A of Fig 1.
Fig. 4 is an enlarged cross-section of a slide guide of the screw type press
machine of Fig. 1.
Fig. 5 is a perspective view of the slide guide of Fig. 4.
Fig. 6 is an enlarged cross-section of a slide guide for a screw type press
machine.
Fig. 7 is a longitudinal iront view of a screw type press machine similar to
that of
Figure 1 having a knockout device according to an embodiment of the present
invention.
Fig, 8 is a side view of an enlarged longitudinal section of the knockout
device of
Fig. 7.
Fig. 9 Is a cross-section along line 111-l1i of Fig B.
Fig.10 is an enlarged perspec.tive view of the slide guide of the screw type
press
machine of Fig. 7.
Fig. 11 is a corresponding cross-section drawing along line III-II of Fig. 8
according to an aiternate embodlment of the present invention.
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Fig. 12 is an enlarged cross-section of the slide guide of the screw type
press machine of Fig. 11
DETAILED DESCRIPTION OF THE INVENTION
6 A screw type mechanical press with which a knockout device embodying
the present invention is illustrated in Figs. 1 through 4. A press machine
body
1 has a pump motor 4 fixed on an upper crown part 3 of a frame 2. A male
screw shaft 6 Is joined and fixed to a power shaft 5 of pump motor 4 through
a joining member. Screw shaft 6 extends to approximately the middle of press
machine body 1. A spherical nut 7, whose lower end is a hemisphere, is
screwed onto screw shaft 8. Sphe'ricai nut 7 is joined and fixed to an upper
slide 8 via a key or the like.
At the center part of a lower slide 9, there is a hole 91, which receives
screw shaft 6 with play. An upper end of lower slide 9 is in spherical contact
with nut 7. Lower slide 9 is hung and fixed to upper slide 8 by a bolt.
Referring to Fig. 4, the slide guide device Is constructed from four fixed
gibs 10, which act as rails, fixed on the inside of frame 2. Eight slide gibs
11
are fixed to each of the four corners of slide 8(9}. Middle liners 12 are
positioned between slide gibs 11 and fixed gibs 10.
Referring to Figure 5, the details of middle liner 12 are shown. An outer
perimeter of middle liner 12 is prefsrably a spherical surface 1 2a. The
opposing
surface, which is on the interior, forms orthogonal planar contact surfaces
12b
and 12c. A recessed part 12d for fixed gib 10 is formed on the ridge line of
the
orthogonal surfaces.
Middle liner 12 is inserted as shown in Fig. 4 in spherical contact with
slide gib 19. Lubrication oil is supplied and middle liner 12 meintains a
bearing
function. Middie liner 12 is shaped so that its rotation center Is always at
the
center of plane contact surfaces 12b and 12c. The maximum displacement in
the radial direction is restricted by a stopper 13, which is fixed by a screw
to
slide gib 11. Furthermore, on the lower part of frame 2, a bolster 15 is
disposed via a bed 14, but the details are omitted.
With this construction, torque is obtained by pump motor 4. When screw
shaft 6 rotates in the direction opposite to the propulsion direction, nut 7,
which
screws on to screw shaft 6, and upper slide 8, which is restricted in rotation
by
fixed gib 10 and slide gib 11 as well as middle liner 12, descend due to screw
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acdon. Lower slide 9, which is joined to the upper slide, desoends in a
unitary manner
as well. On the four comers of siide 8(9), middle liners 12 are in two-surface
contact
with fixed gib 10 and are in spherical contact with slide gib 11. In addition
the oenter of
rotation of middle liner 12 is at the center of the planar contact surfaces.
As a resuit,
even If there Is an eccantric load on the slide, due to the self-aligning
action of the middle
= =~
liner, the stress is absorbed, and a smooth descending motion results.
In addition, lower slide 9, which has the die, and upper slide 8 are
separated,
The screw torque fonce generated on upper slide 8 is not directly transferred
to the lower
slide, and the torque is greatly suppressed at the time of product working.
Referring to Figure 6, another slide guide is shown. Planar contact surfaces
12b
and 12c are formed orthogonally on the exterior of middle liner 12. Fixed gib
10 has a
perpendicular depression surface opposite planar contact surFacxs 12b and 12c.
Furthermore, although the middle liner was described with reference to a screw
type press machine was described, however, the middle liner Is efrective in
all slide guide
devices having an eccentrlc load at the time of load transfer.
A result of disposing a middle liner, in which one side has a spherical
contact and
the other side has a plane contact, between a fixed gib and a slide gib, is
that the slide
guide device is self-aligning and effective for eccentric loads.
A stable and a strong construction is achieved by having the plane contact
surface of the middle layer be two orthogonal surfaces and by having them
contact the
fixed gib.
A slide guide device with a construction that is stable and strong Is obtained
by
having the middle liner a small size by forming, in a shell shape, two plane
contact
surFaees which orthogonally intersect in the interior. 25 A slide guide device
in which smooth movement is possible by having a recessed part formed along
the ridge line of the orthogonal planes of the middle liner.
Furthermore, such a slide guids device does not suffer from mechanical
scuffing.
A self-aligning mechanism which is always stable is obtained by having a
construction in which the rntation center of the middle liner is positioned in
the middle of
the slide plane.
TOTAL P.03
le 04/11/Z008 ~14 58 ~613 254 9222
Qreceived
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Embodiments of the invention are applicable to press machines having
a fixed gib, which is disposed in a fixed manner at four corners on the
perimeter, and a middle liner, which is disposed between the fixed gib and the
slide gib and which contributes to the motion of the slide. One side of the
middle layer is in spherical contact with the slide gib. The other side
contacts
the fixed gib by two surfaces which are orthogonal. As a result, a highly
reliable press machine is provided in which an eccentric load on the slide
does
not influence the product precision.
The slide is constructed from an upper slide, which moves vertically in
response to the screw action of a rotation screw shaft, and a lower slide,
which
is joined to the upper slide and fits with the screw shaft in a manner that
allows
for play therebetween. In addition, by placing a middle liner on the top and
bottom four corners of each of the slides, the influence on the lower slide,
which is provided with a die, from an eccentric load is minimized, resulting
in
a press machine having a high working precision.
A nut, which is joined to the upper slide and screws onto the screw
shaft, is provided, and this nut contacts the lower slide with a spherical
surface.
The upper and lower slides are joined by a screw. As a result, a press machine
is provided in which an eccentric load is not directly transferred to a lower
slide.
Moreover, a slide guide device is provided in which, even if an eccentric
load acts on the slide, self-alignment is possible and a smooth motion is
conducted. In addition, a press machine is provided having a simple
construction, an excellent eccentric load resistant property, and a high
working
precision.
Referring to Figs. 7 through 10, an embodiment of the present invention
is described according to a screw type mechanical press as depicted.
Referring to Figs. 7 through 10, press machine body 1 has pump motor
4 affixed to upper crown part 3 of frame 2, Male screw shaft 6 is joined and
affixed to power shaft 5 of pump motor 4 through a joining member comprising
a flange 61. Screw shaft 6 extends to approximately the middle of the press
machine body. Spherical nut 7, whose lower end is a hemisphere, screws onto
screw shaft 6. Spherical nut 7 is joined and affixed to upper slide 8 through
a
key or the like.
At a center part of lower slide 9, hole 91 receives screw shaft 6 with
play therebetween. The upper surface of lower slide 9 is opposite and is in
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spherical contact with spherical nut 7 via a seat 112. Lower slide 9 is hung
and
affixed to upper slide 8 by a bolt.
Referring to Figures 8 through 10, a knockout device 16, according to a
preferred embodiment of the present invention, is described in detail. A pair
of
tubular or cylindrical guide rails 17 is planted substantially upright at
approximately the center of the press machine. Knockout block 19 is disposed
in a freely sliding manner on guide rails 17 via a plurality of middle liners
18,
which comprise bearing materials and the like. Knockout block 19 is disposed
opposite a knockout pin 22 of a lower holder 21, which is mounted on top of
boister 20. Knockout block 19 has approximately the same plate pressure as
guide rail 17. A tubular hole 23 is formed in the lower end center of knockout
block 19.
Referring specifically to Figure 10, as shown in detail, on its outer
perimeter, middle liner 18 preferably has a hemispherical surface 18a, which
is
in surface contact with circular surface 1 9a of knockout 19. Inner perimeter
circular surface 18a of middle liner 18 is in contact with the outer perimeter
surface of guide rail 17. Furthermore, middle liner 18 has a protrusion 18c at
the outer perimeter summit part of middle liner 18. The construction of middle
liner 18 provides for a positional relationship with knockout block 19 in
which
slipping down is prevented.
A slider 25, having an eccentric shaft 24, is inserted into tubular hole 23.
A knockout lever 28 is held at approximately its central part in a freely
rotating
manner on shaft 26 with spherical bearing 27. Shaft 28 is provided on bolster
20. One end of a two-branched knockout lever 28 is engaged on eccentric
shaft 24. The other end of knockout lever 28 is engaged at clevis 31 at one
end of piston rod 30 of a double acting double rod hydraulic cylinder 29,
which
provides the motion source for the knockout lever.
Referring now to Figure 7, with double acting double rod hydraulic
cylinder 29, the oil, which is supplied from a tank 32, is pressurized and
controlled by a manual variable hydraulic pump 33. Furthermore, hydraulic
pump 33 is driven by energy stored by a motor M through a fly wheel 34.
Energy transfer is conducted with a clutch mechanism 36, which is controlled
by a driving source 35 of air and the like. Therefore, the arrangement has the
advantage of supplying hydraulic pressure generating energy in a stable manner
with a very small power source. Furthermore, when the hydraulic pressure
CA 02614672 2008-10-01
inside the hydraulic circuit exceeds a set value, there is a pressure control
valve
37 for guiding oil to a tank 32, to protect the hydrauiio circuit.
With this construction, torque is achieved by pump motor 4. When
screw shaft 6 rotates in the direction opposite to the propulsion direction,
nut
5 7, which screws on to screw shaft 6. Upper slide 8, which is res#rained from
rotation by fixed gibs 10, slide gibs 11, and middle liner 12, descends due to
screw action. Lower slide 9, which is joined to upper slide 8, descends in a
unitary manner. Because lower slide 9, on which the die is on, and upper slide
8 are separated, the screw torque generated on upper slide 8 does not directly
10 transfer to lower slide 9. The twisting force at the time of product
working is
greatly reduced.
Next, regarding the knockout device according to an embodiment of the
present invention, the oil supplied from tank 32 is compressed by a hydraulic
pump 33, driven by the torque of fly wheel 34 in which rotational energy is
from motor M is stored. Piston rod 30 of cylinder 29 moves as a resuit. From
this, when piston rod 30 moves downward in the figure, the other end of
knockout iever 28 moves upward along the path drawn with shaft 28 as the
center. As a result, eccentric shaft 24 also moves with a similar curvature
radius.
However, this movement is changed to a linear motion In the vertical
direction by slider 25. The eccentric load on knockout block 19 is greatly
suppressed, and smooth movement is possible. In addition, a plurality of
middle
liners are disposed between guide rail 17 and knockout block 19. As a result,
even if an eccentric load arises in the knockout block, each of the middle
liners
absorbs the eccentric load (self-alignment), and a smooth motion can be
continued.
Referring to Fig. 10, by a combination of spherical surfaces, middle liner
18 is easily positioned between guide rail 17 and knockout block 19. As a
result, stable knockout is possible with an extremely simple and small energy
source. The effect on resource conservation is great.
Referring to Figs. 11 and 12, an alternate embodiment of the present
invention is shown. This embodiment is substantially the same as that
previously described, however, the guide rail is a triangular pole 171, and
the
inner surface of middle liner 181 is processed into a triangle. Middle liner
181
slides on triangular pole 171 by a two surface contact. In addition, the outer
CA 02614672 2008-10-01
surface, which is processed into a spherical surface, is in surface contact in
a
freely pivoting manner with the spherical cavity formed on one side surface of
knockout block 191. The details will be omitted, but all of the sliding
surfaces
are lubricated as needed, and appropriate combinations of materials are
selected.
According to embodiments of the present invention, a knockout device
Is provided, wherein a plurality of middle liners, which have at least one
surface
as a spherical surface, is disposed between a side surface of a knockout block
and a pair of guide raiis. The guide rails are disposed and affixed opposite
the
block side surface. By guiding the knockout block, even if there is some
eccentric load on the knockout block, there is a self-alignment action, and
the
movement of the block operates smoothly, lightly, and quietly.
A knockout device operates in a stable manner with an extremely simple
mechanism by having a tubular or cylindrical guide rail, and by having such a
guide rail in surface contact with the other surface of the middle liner.
A knockout device is provided having a guide mechanism with a high
mechanical strength by having a triangular pole guide rail, and by having such
a guide rail have a two surface contact with the other surface of the middle
liner,
A knockout lever has one end linked to a motion source which moves
vertically. The lower end of the knockout block is pivotably connected to the
other end of the knockout lever through an eccentric pivoting mechanism. As
a result, a knockout device is provided in which the pushing up force in the
perpendicular direction is always stable and not dependent on the movement
pathway of the knockout lever.
The motion source which moves the knockout lever is a double acting
double rod type hydraulic cylinder. Oil is supplied from a hydraulic tank, and
the
cylinder compresses and controls the oil by a variable hydraulic pump, which
is
driven by a motor. Rotational energy is stored between this hydraulic pump and
the motor. In addition, a fly wheel is provided with a clutch which is opened
and closed by external control. As a result, an energy conserving knockout
device is provided which is simple and smalJ.
After storing the rotational energy of the motor in the fly wheel, the
rotational energy is supplied to the hydraulic pump through the clutch, which
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is opened and closed by external control. As a result, a knockout device is
provided which is small and energy conserving.
When the oil pressure inside the hydraulic supply circuit exceeds a
predetermined standard value, a pressure control valve operates, and oil is
guided to the tank. As a result, a safe knockout device is provided which
prevents oil leakage.
In embodiments of the present invention, a knockout device for a press
machine which has low noise and is energy conserving is provided by a simple
construction. The energy needed for the knockout is small, and operation is
always conducted under a stable knockout load.
Having described preferred embodiments of the invention with reference
to Figures 7 to 12 of the accompanying drawings, it is to be understood that
the invention is not limited to those precise embodim$nts, and that various
changes and modifications may be effected therein by one skilled in the art
without departing from the scope of the invention as defined in the appended
claims.
