U.S. patent number 3,564,959 [Application Number 04/780,051] was granted by the patent office on 1971-02-23 for fine blanking press.
This patent grant is currently assigned to Kabushiki Kaisha Aida Fekkosho, Kanagawa-ken, JP. Invention is credited to Suguru Harada.
United States Patent |
3,564,959 |
|
February 23, 1971 |
FINE BLANKING PRESS
Abstract
A fine blanking press comprising a punch holder mounted on the
bolster of said press; a blank holder loosely fit in said punch
holder encircling a punch; a first cylinder provided in said
bolster; a first piston for indirectly supporting said blank
holder; a first booster for supplying oil pressure to said first
cylinder; a die holder mounted in the slide of said press for
supporting a die; a counter blank holder received in said die; a
second piston fit in a second cylinder provided in said slide for
indirectly applying oil pressure to said counter blank holder; a
second booster for supplying oil pressure to a chamber above said
second piston; and means for controlling and maintaining oil
pressure within a chamber below said second piston.
Inventors: |
Suguru Harada (Kanagawa-ken,
JP) |
Assignee: |
Kabushiki Kaisha Aida Fekkosho,
Kanagawa-ken, JP (N/A)
|
Family
ID: |
25118415 |
Appl.
No.: |
04/780,051 |
Filed: |
November 29, 1968 |
Current U.S.
Class: |
83/124; 100/218;
83/137 |
Current CPC
Class: |
B21D
28/16 (20130101); Y10T 83/2153 (20150401); Y10T
83/2124 (20150401) |
Current International
Class: |
B21D
28/02 (20060101); B21D 28/16 (20060101); B26d
007/18 () |
Field of
Search: |
;83/124,137 ;100/218
;72/344,345 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: James M. Meister
Attorney, Agent or Firm: William W. Downing, Jr.
Claims
I claim:
1. A fine blanking press, comprising a punch holder secured to the
bolster of said press for holding a punch; a blank holder
encircling said punch and loosely fit in said punch holder; a first
piston received in a first cylinder provided in said bolster and
supporting said blank holder through intermediate means under the
action of oil pressure; a first booster for supplying oil pressure
to said first cylinder; a die holder fixedly secured to the slide
of said press for supporting a die; a counter blank holder adapted
to loosely fit in said die; a second piston received in a second
cylinder provided in said slide for applying pressure on said
counter blank holder through intermediate means under the action of
oil pressure present in an upper chamber of said second cylinder; a
second booster for supplying oil pressure to an oil chamber above
said second piston; and means for controlling oil pressure in a
chamber below said second piston to maintain the oil pressure at a
predetermined value or release such oil pressure therefrom.
2. A fine blanking press as set forth in claim 1, in which said
means for controlling oil pressure in said chamber below the second
piston comprises an oil tank; a line providing communication
between said tank and chamber; a check valve in said chamber; an
oil cylinder in communication with said chamber; a piston received
in said chamber; a rotary cam for operating said piston; and a
third booster adapted to open said check valve.
3. A fine blanking press as set forth in claim 2, in which said
first booster has an oil chamber which is communicated through a
second check valve with an oil chamber in said first cylinder and
said second check valve is adapted to be opened by said third
booster.
4. A fine blanking press as set forth in claim 3 inclusive, in
which said second booster has an oil chamber which is communicated
with an upper chamber of a second cylinder provided in said slide
and said second booster has a compressed air chamber which is
communicated with a compressed air supply source.
5. A fine blanking press as set forth in claim 4, in which said
press further includes a third booster having an oil chamber which
is communicated through a third check valve with an oil pump which
is adapted to be driven by an electric motor and said compressed
air chamber of the second booster is communicated through an
electromagnetic valve with said compressed air supply source.
6. A fine blanking press as set forth in claim 5, in which said
press further includes a pump means adapted to automatically supply
oil to the oil chamber in said first booster when the oil pressure
within said first booster oil chamber has dropped to values below a
predetermined value.
7. A fine blanking press as set forth in claim 6, in which said
press further includes a second pump means adapted to automatically
supply oil to the oil chamber of said second booster when the oil
pressure within said second booster oil chamber has dropped to
values below a predetermined value.
Description
There have been proposed various types of fine blanking presses
which essentially comprise elements such as punches, dies, blank
holder and counter blank holder, but all of the prior art blanking
presses have rather complicated constructions and accordingly, the
operation of such presses is inevitably complex which makes it
difficult to produce blanked pieces having desired precise
dimensions and shapes and necessitate additional operation or
operations for finishing the incomplete blanks to the precise
dimensions and shapes called for. Furthermore, in any of such prior
art fine blanking presses the counter blank holder can not be
completely locked in position and the die is frequently snugly fit
in the mating die leading to the breakage of the punch and/or die
whereby the service life of the these parts is shortened.
The present invention relates to a fine blanking press of the type
in which a punch, a die, a material support plate and a counter
blank holder constitute essential component parts of said press and
these component parts are actuated by their respectively associated
pneumatically operated oil pressure boosters, respectively.
One object of the present invention is to provide a vertical or
horizontal fine blanking press in which a punch, a die, a blank
holder and a counter blank holder which constitute essential
component parts of said press are actuated by very simplified
pneumatically operated oil pressure boosters which are respectively
associated with these parts.
Another object of the present invention is to provide a fine
blanking press which has a very simplified construction and can
produce any desired blank having predetermined precision dimensions
and shape in a single step of operation whereby eliminating the
necessity for any additional finish process.
A further object of the present invention is to provide a fine
blanking press in which a counter blank holder is adapted to be
completely locked in position so as to prevent a punch from snugly
fitting in a die adapted to effect blanking a material in
cooperation with said punch whereby the punch and die may be
protected from free of any possible damage which would occur
otherwise resulting in the extension of the service life of the
punch and die.
According to the present invention, there is provided a fine
blanking press, comprising a punch holder fixedly secured to the
bolster of said press for holding a punch therein; a blank holder
encircling said punch and loosely fit in said punch holder; a first
piston received in a first cylinder provided in said bolster and
supporting said blank holder through intermediate means under the
action of oil pressure; a first booster for supplying oil pressure
to said first cylinder; a die holder fixedly secured to the slide
of said press for supporting a die; a counter blank holder adapted
to loosely fit in said die; a second piston received in a second
cylinder provided in said slide for applying pressure on said
counter blank holder through intermediate means under the action of
oil pressure in an upper chamber of said second cylinder; a second
booster for supplying oil pressure to an oil chamber above said
second piston; and means for controlling oil pressure in a chamber
below said second piston to maintain the oil pressure at a
predetermined value or release such oil pressure therefrom.
The above and other objects and advantages of the present invention
will be more apparent to those skilled in the art from a reading of
the following description referring to the accompanying
drawing.
BRIEF DESCRIPTION OF THE DRAWING
The sole FIGURE of the drawing is a vertical section view of
principal parts of a preferred form of fine blanking press
according to the present invention and which also diagrammatically
shows the oil pressure circuit system and the compressed air
circuit system to be employed in conjunction with said press.
EMBODIMENT OF THE INVENTION
The present invention will now be described referring to the sole
FIGURE of the accompanying drawing in which a preferred form of
fine blanking press according to the present invention is shown in
a vertical section view together with its oil pressure and
compressed air circuit systems which are diagrammatically shown.
The novel blanking press generally comprises a bed 1 having a
bolster 2 fixedly mounted on the top thereof by means of bolts 2'
and the bolster in turn has a punch holder 4 fixedly mounted on the
top thereof by means of bolts 4'. The punch holder 4 fixedly
carries a punch 5 therein by means of bolts 6 and is provided on
the upper surface with a recess 7 for loosely receiving a hollow
blank holder 8 which is adapted to slide vertically within the
recess in slide contact with the periphery of the punch 5. The
bolster 2 further has a pressure ring 3 received in a recess on the
upper surface thereof and the ring is fixedly held in position
within the recess by means of bolts 3'. The pressure ring 3 loosely
receives a pressure pad 9 therein and a pin 10 extends between the
bottom surface of the blank holder 8 and the upper surface of the
pressure pad 9 loosely piercing through the punch holder 4. The
bolster 2 has an oil cylinder 12 defined therein whose transverse
dimension is larger than that of the upper opening in which the
pressure pad 9 is received and a vertically reciprocal piston 11 is
received within the oil cylinder. The piston 11 has an integral
upper extension 11a received in the upper opening in the bolster 2
and in abutment with the bottom surface of the pressure pad 9. The
oil cylinder 12 defines an oil chamber a therein and the oil
chamber is communicated through a pilot check valve 13 with an oil
chamber b defined in a booster A which is disposed in the opening
in the bed 1. The oil chamber b provided in the booster A is
communicated through a line of the oil pressure circuit system with
an oil supply pump D which is in turn communicated through a line
with an oil tank 14. The oil supply pump D may be of any
conventional compressed-air operated pump and is also communicated
through an electromagnetic valve 15, a line 16 and a pressure
regulating valve 17 with a compressed air supply source P. The
booster A comprises an air cylinder 18 in which a piston 19 is
disposed for vertically reciprocal movement and an oil cylinder 20
in which a plunger 19a integrally formed with a piston 19 is
disposed. A pin 22 extends through the top wall of the air cylinder
18 and the upper end portion of the pin extends above the air
cylinder and is surrounded by a coil spring 21 which is received a
suitable housing mounted on the top of the cylinder 18 and which
urges the lower end of the pin 22 against the upper surface of the
piston 19. The extreme upper end of the pin 22 is in normally
contact with the operating piece 23a of a limit switch 23 which is
adapted to control the electromagnetic valve 15 as will be in
detail described hereinafter. The air cylinder 18 of the booster A
defines an air chamber c which is communicated through a line 24
and a pressure regulating valve 25 with the compressed air supply
source P.
Reference numeral 26 denotes the lower portion of a slide in the
press which is adapted to be moved vertically and reciprocally by a
suitable drive means such as a crank shaft (not shown). The slide
26 has a die holder mounting plate 27 fixedly secured to the lower
end face thereof by means of bolts 28 and the mounting plate in
turn has a die holder 29 fixedly secured to the lower end face
thereof by means of bolts 28 and the mounting plate in turn has a
die holder 29 fixedly secured to the lower end face thereof by
means of bolts 29'. A hollow die 30 which mates and cooperates with
the punch 5 is fixedly secured to the lower end face of the die
holder 29 by means of bolts 31. The die holder 29 is provided on
the bottom surface with a recess 32 for loosely receiving the
enlarged upper portion of a counter blank holder 33 while the lower
reduced portion of the counter blank holder is loosely fit in the
opening in the die 30. A pin 37 extends vertically and loosely
through the die holder 29 between the bottom surface of a pressure
pad 36 loosely received in a pressure ring 35, which is in turn
fixedly secured to the mounting plate 27 by means of bolts 34, and
the upper surface of the counter blank holder 33. The upper surface
of the pressure pad 36 abuts against the bottom surface of the
lower extension 39a integrally formed with a piston 39 received in
an oil cylinder 38 defined in the slide 26. The upper oil chamber d
provided in the upper portion of the oil cylinder 38 is
communicated through a line 40 with the oil chamber e of a second
booster B.
The second booster B has substantially the same construction as
that of the first-mentioned booster A and comprises a lower air
cylinder 41 in which a piston 42 is disposed for vertical and
reciprocal movement and an upper oil cylinder 43 in which a plunger
42a integrally formed with the piston 42 is received. A pin 45
vertically extends through the top wall of the air cylinder 42
having the lower end abutting against the upper surface of the
piston 42 and the upper end portion of the pin is surrounded by a
coil spring 44 which is in turn received in a housing fixedly
disposed on the top wall of the air cylinder 41. The extreme upper
end of the pin 45 abuts against the operating piece 46a of a limit
switch 46. The limit switch 46 is adapted to control an
electromagnetic valve 48 in a manner which will be in detail
hereinafter. The oil cylinder 43 defines an oil chamber e therein
and the oil chamber is supplied with oil from an oil tank 47 by a
suitable conventional feed pump E which may be a conventional
pneumatically operated type. The pump E defines an air chamber
therein and the air chamber is communicated through a line 49
including the above-mentioned electromagnetic valve 48 and pressure
regulating valve 17 with the compressed air supply source P. The
air cylinder 41 defines an air chamber f therein and the air
chamber is communicated through a line 51 including an air pressure
regulating valve 50 with the compressed air supply source P.
The cylinder 38 provided in the slide 26 defines an oil chamber g
below the piston 39 and the oil chamber is communicated through a
pilot check valve 52 and a line 53' with an oil tank 53. The oil
chamber g is also in communication through a line 54 with a
cylinder 55 in which a piston 56 is disposed for vertical and
reciprocal movement and the piston has a roller 58 mounted thereon
by means of a transverse pin 57. The roller 58 is in engagement
with a cam 60 on a transverse rotary shaft 59 which is adapted to
rotate in synchronization with the crank shaft (not shown) which
drives the press slide 26.
The above-mentioned pilot check valves 13 and 52 are communicated
through a line 53a with an oil chamber h defined by the oil
cylinder 61 of a third booster C and these valves are also
communicated through a line check valve 62 with a lubricant feed
pump 63 which is adapted to be driven by an electric motor 64.
Reference numerals 65 and 66 denote an oil tank and a relief valve,
respectively. The lubricant feed pump 63 is communicated through a
line 67 and a line check valve 68 with the above-mentioned cylinder
55.
The third booster C comprises an air cylinder 69 in which a piston
70 is disposed for horizontal and reciprocal movement and the oil
cylinder 61 in which a plunger 70a integrally formed with the
piston 70 is disposed. The air cylinder 69 defines an air chamber k
therein and the air chamber is communicated through a line 71, an
electromagnetic valve 72 and an air pressure regulating valve 73
with the compressed air supply source P. The electromagnetic valve
72 is adapted to be controlled by a limit switch 75 which is in
turn adapted to be controlled by a rotary cam 74 mounted on the
above-mentioned rotary shaft 59 at the end remote from the end on
which the stationary cam 60 is mounted. Reference numerals 76
denotes a stop valve disposed in the compressed air supply circuit
and normally blocking the flow of compressed air in the circuit,
and reference numeral 77 denotes pressure gauges which are adapted
to indicate the air pressure in the lines in the compressed air
supply circuit system which lines are associated with the boosters
A, B and C, respectively.
In operation, the stop valve 76 is opened so as to permit a flow of
compressed air to be fed from the compressed air supply source P
through the pressure regulating valve 25 into the air cylinder
chamber c in the first booster A. Whereupon the piston 19 within
the air chamber c is pushed upwardly and accordingly, the plunger
19a integral with the piston 19 is also pushed up to compress the
oil within the oil chamber b thereby to increase the pressure on
the oil to a predetermined value. If the oil pressure within the
oil chamber b fails to reach or rise to a predetermined value from
one cause or another, then, the pin 22 is caused to move up to
operate the limit switch 23. When energized in the manner mentioned
just above, the limit switch 23 opens the electromagnetic valve 15
whereby the oil feed pump D is actuated to pump up oil from the oil
tank 14 and force the oil through the line, which leads from the
tank to the booster A, into the oil chamber b in the oil cylinder
20. The pumping of oil by the feed pump D is continued until the
oil pressure within the oil chamber b has reached to the
predetermined value whereupon the piston 19 descends down and
accordingly, the pin 22 also descends down to operate the limit
switch 23. The limit switch 23 closes the electromagnetic valve 15
thereby to stop the oil feed pump D.
The upper oil chamber d defined in the cylinder 38 is normally
subjected to the pressure of the oil from the oil chamber e in the
second booster B which is actuated by compressed air supplied from
the compressed air supply source P via the air pressure regulating
valve 50, but if the oil pressure within the oil chamber d fails to
reach a predetermined value from one cause or another, the pin 45
is caused to move up to operate the limit switch 46. When operated
in the manner mentioned above, the limit switch 46 opens the
electromagnetic valve 48 whereby the oil feed pump E is actuated to
pump up oil from the oil tank 47 and force the oil through the
line, which leads from the tank to the second booster B, into the
oil chamber e in the oil cylinder 43. The pumping of oil by the
feed pump E is continued until the oil pressure within the oil
chamber e has reached the predetermined value whereupon the piston
42 descends down and accordingly, the pin 45 descends down to
deenergize the limit switch 46. The operation of the limit switch
23 closes the electromagnetic valve 15 thereby to stop the oil feed
pump E. Thus, the oil pressure within the oil chamber d is
maintained at the predetermined value.
The above-mentioned lubricant oil feed pump 63 is adapted to be
operated by the electric motor 64 only when the amount of oil
within the oil chamber g in the cylinder 38 and/or that within the
oil chamber h in the third booster C is insufficient for proper
operation of the press. When operated, the pump 63 feeds oil under
pressure through the line check valve 62 into the oil chambers g
and h / or either one of these oil chambers until the oil chambers
have been filled to a predetermined level for proper operation of
the press. Whereupon the preparatory procedure for effecting a
cycle of blanking operation on the press is ready for
commencement.
When a cycle of blanking operation is to be performed on a material
by the use of the above-mentioned press, as usually followed, the
slide 26 descends thereby to cause the die 30 carried by the slide
and the cooperating stationary punch 5 to shear a desired blank off
material which is held in position on the punch 5 and blank holder
8. When the blank is sheared off the remaining material in the
manner mentioned just above, the counter blank holder 33 which
abuts against the material is caused to retreat deeper into the
recess 32 in the die holder 29 which is carried by the slide 26 and
the counter blank holder pushes up the piston 39 and its integral
plunger 39a by means of the pin 37 and pad 36. Whereupon the oil
within the oil chamber d in the cylinder 38 is forced to flow
through the line 40, which leads from the cylinder 38 to the second
booster B, into the oil chamber e in the cylinder 43 of the second
booster B. In such a case, since the volume of the oil chamber g in
the cylinder 38 increases, an additional amount of oil, the amount
of which corresponds to the increase in the volume of the oil
chamber g, is introduced from the tank 53 through the pilot check
valve 52 and at the same time the piston 56, which is adapted to be
actuated by the cam 60 on the rotary shaft 59 at the completion of
a cycle of blanking operation, forcibly feeds oil from the cylinder
55 into the oil chamber g of the cylinder 38 thereby to hold the
piston 39 in its present position or raised position. The piston 39
is maintained in this position until the slide 26 rises up to a
predetermined point in its upward stroke whereupon the limit switch
75, which is adapted to be actuated by the rotary cam 74 on the
rotary shaft 59, provides a signal to open the electromagnetic
valve 72 which in turn moves the piston 70 of the third booster C
leftwards as seen in the FIG. to compress the oil within the oil
chamber h of the same booster. The compressed oil within the oil
chamber h opens the pilot check valve 52. Simultaneously, the cam
60 on the rotary shaft 59 allows the piston 56 to rise and
accordingly, the oil within the oil chamber g of the cylinder 38
returns to the tank 53 and cylinder 55 whereby the oil pressure
within the oil chamber g is reduced resulting in the oil within the
oil chamber e of the second booster B being fed into the upper oil
chamber d of the cylinder 38. As mentioned above, since the oil
pressure within the oil chamber g of the cylinder 38 and the force
which holds the piston 39 against its downward movement is removed
from the piston 39, the piston is pushed down and the extension 39a
of the piston 39 pushes down the counter blank holder 33 through
the pad 36 and pin 37 whereby the blanked piece (not shown) may be
pushed out of the die 30.
On the other hand, when the blank holder 8 is pushed down by the
slide 26 through the material supported thereon, the blank holder 8
pushes down the piston 11 through the pin 10 and pad 9.
Accordingly, the oil within the cylinder chamber a is fed through
the pilot check valve 13 into the oil chamber b of the first
booster A and the piston maintains this position during the period
from the time at the completion of blanking operation to the time
at which the slide 26 reaches a predetermined point in its upward
stroke. When the slide 26 has reached the above-mentioned
predetermined point the rotary cam 74 on the rotary shaft 59
operates the limit switch 75 which in turn opens the
electromagnetic valve 72. The opening of the electromagnetic valve
72 causes the oil pressure within the oil chamber h of the third
booster C to open the pilot check valve 13 whereby the oil within
the oil chamber b of the first booster A returns to the oil chamber
a of the cylinder 12 to push up the piston 11 whereby the blank
holder 8 is pushed up through the pad 9 and pin 10 to its original
position. Thus, one cycle of blanking operation by the use of the
novel blanking press has been completed.
Although the present invention has been illustrated and described
as being applied to a vertical fine blanking press, it will be
understood that the invention may be also applied to a horizontal
fine blanking press without departing the scope of the same.
According to the present invention, as mentioned above, air
pressure actuated oil pressure boosters are employed for actuating
the punch, die, material support member and counter blank holder
and accordingly, as compared with the conventional like-type
blanking presses, the novel fine blanking press can be fabricated
with a very simplified and compact design. Since the cooperating
material support member and counter blank holder are designed to
precisely function, pieces produced by the novel blanking press may
have precisely predetermined dimensions and shapes which require no
additional or finish operation for correcting or adjusting the
dimensions and shapes of the pieces. Furthermore, since the counter
blank holder is designed to be perfectly locked or pushed up, there
will be no possibility that the punch is snugly fit in the die
during the operation whereby the punch may be protected from any
damage due to such a snug fit resulting in the extension of the
service life of the punch. In addition, no compressed air is
discharged out of the compressed air recycling circuit system of
the press to the atmosphere and consumption or waste of compressed
air in the system may be reduced to a minimum level.
While one preferred embodiment of the present invention has been
shown and described in detail, it will be understood that the same
is only illustrative in nature and not to necessarily limiting upon
the scope of the teaching in its broader aspect. Many additional
variations and changes within the scope of the appended claims will
occur to those skilled in the art.
* * * * *