EP3584019B1

EP3584019B1 - Stripping device for press mold

Info

Publication number: EP3584019B1
Application number: EP17896382.3A
Authority: EP
Inventors: Yoon Sun Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-02-14
Filing date: 2017-02-14
Publication date: 2022-06-29
Anticipated expiration: 2037-02-14
Also published as: WO2018151337A1; EP3584019A4; JP2020501909A; EP3584019A1; JP6792121B2; CN110087794B; CN110087794A

Description

[Technical Field]

The present invention relates to a stripping device for a press mold, and more particularly to a stripping device for a press mold, which has an improved structure designed to separate a panel from a punch when the punch is retracted rearwards after performing a punching operation using a press mold in order to prevent the panel from being lifted along with the punch, thereby improving productivity and efficiency in a punching operation.

[Background Art]

In general, a cam unit for a mold is mounted on a press mold such that the cam unit is able to be tilted so as to change the direction of operation in a vertical reciprocating movement. As illustrated in FIG. 1, a cam slider 3 is mounted on the lower surface of a box-shaped cam base 1 so as to be anteroposteriorly slidable, and is provided therein with a spring hole 6 into which a return spring 5 is inserted. A cam driver 7 is provided under the cam slider 3.
In an operation of the cam unit, which is constructed in the above-described manner, when the entire cam base 1 is lowered and a slide groove 8 in the lower surface of the cam slider 3 is moved along a slide plate 9 disposed on the cam driver 7, the return spring 5 is compressed against the restoring force thereof and the cam slider 3 is moved forward so as to cause a punch 16 to punch a panel securely held in a jig 14, as illustrated in FIG. 2.
However, because the conventional cam unit is constructed such that the punch, which has performed a punching operation on a panel product, is returned only by the elastic restoring force of the return spring, frictional resistance between the punch and the panel is increased in the case of recent panels such as a high-tensile steel plate having increased tensile strength and the case of a panel having increased thickness, thereby frequently causing problems with the returning movement of the punch. Hence, there are problems whereby a high-speed punching operation is impossible or the cam slider or the punch breaks.
Although a return spring having high elasticity has been used to return the cam slider, there are problems whereby it is difficult to mount and hold the return spring having high elasticity and the cam unit is separated due to the high elasticity of the return spring during operation thereof, thereby causing a safety problem.
In addition, although the cam slider has to be moved forward at the moment of collision when the cam slider comes into contact with the cam driver, the cam slider cannot be smoothly moved forwards due to the high elasticity of the return spring, thereby increasing impulsive force. Subsequently, because the surface pressure between the contact surfaces is increased even while the cam driver is moved forwards, wear of the contact surfaces is accelerated, thereby shortening the service life of the cam device.
JP2007175779A discloses a puncher comprising a piercing punch, a punch retainer for holding the piercing punch, a cover which covers the piercing punch, from which the tip part of the piercing punch is projected and in the inside of which the whole punch retainer is housed, a stripper which is externally fitted to the piercing punch, pressing a work before piercing the work with the piercing punch, pulling out the piercing punch of the work after piercing, being housed in the cover and movable back and forth and having a stop flange formed at the rear end, and coil spring which is brought into contact with the stop flange of the stripper housed in the cover, with which the stripper outward is energized and also which is housed in the housing chamber.

[Disclosure]

[Technical Problem]

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a stripping device for a press mold, which is constructed such that a punch and a panel are able to be more conveniently separated from each other after a punching operation and a push member for pressing a panel is able to be replaced even in the state in which a punch holder and the punch are securely mounted on the front surface of the cam slider.
It is another object of the present invention to provide a stripping device for a press mold, which is provided with disc springs that are stably stacked in which the stacked structure and the number of disc springs are set according to the kind of panel, thereby ensuring smooth return movement of a cam slider and improved efficiency of a punching operation.
It is a further object of the present invention to provide a stripping device for a press mold, which is able to be directly mounted on an existing punch holder and makes it convenient to perform attachment and detachment of a push member received therein, thereby improving convenience in assembly operation and use, and which enables a worn push member to be promptly replaced during a punching operation, thereby increasing efficiency in the production of products.

[Technical Solution]

In order to solve the above technical problems, the present invention provides a stripping device (100) for a press mold, in which a punch holder (10) including a punch (16) is mounted on a front surface of an upper mold or a cam slider (3) for a press mold and in which a housing (30), which is provided therein with an elastic member (50) and a push member (70), is fixedly mounted on a front surface of the punch holder (10) such that the push member (70) is compressed against restoring force when contacting an object to be punched, the stripping device (100) including the housing (30), which includes a push-member-sliding portion (31) and an elastic-member-receiving portion (35), which are continuously formed in an inner cylindrical surface thereof toward a rear side from a front side, the housing (30) including a support flange (39) having therein a fixing hole (39a), which is formed in an outer peripheral surface of a rear end thereof so as to be coupled to the front surface of the punch holder (10) by means of a bolt, a movable plate (40), which is inserted into the elastic-member-receiving portion (35) from the rear side and is blocked by a stepped portion formed between the elastic-member-receiving portion (35) and the push-member-sliding portion (31), the movable plate (40) including a central hole through which the punch (16) passes, the elastic member (50) having therein a central hole through which the punch (16) passes, the elastic member (50) being inserted into the elastic member-receiving member (35), and the elastic member (50) being compressed when the movable plate (40) is moved along the elastic-member-receiving portion (35), a fixed plate (60) including a central hole through which the punch (16) passes, the fixed plate (60) being inserted into an inner peripheral surface of the elastic-member-receiving portion (35) through a rear open end of the elastic-member-receiving portion (35) and then being coupled to the rear end of the housing (30) by pressing the rear end of the housing (30) inwards, the push member (70) including a guide part (71) provided at a rear side thereof, the guide part (71) being slidably inserted into the push-member-sliding portion 31 from the front side of the housing (30) and coming into contact with the movable plate (40), and a projection part (72) provided at a front side thereof, the projection part (72) having a diameter smaller than that of the guide part (71), the push member (70) including a longitudinal pin through hole (73) through which the punch (16) is moved, and a retaining ring (80), which is removably fitted into a ring-fitting groove (32) formed in an inner peripheral surface of a front end of the push-member-sliding portion (31) so as to prevent the guide part (71) of the push member (70) from being moved forwards.
The fixed plate (60) may be fitted into a fixed-plate-fitting groove (36), which is formed in a rear end of the elastic-member-receiving portion (35) so as to have a stepped portion, and the fixed plate (60) may be provided on an outer peripheral surface thereof with an inclined surface (61), which has a smaller diameter at a rear end thereof than at a front end thereof, and may be forcibly fitted into the rear end of the housing (30) so as to be integrally coupled to the housing (30). Alternatively, the elastic-member-receiving portion (35) may include a concave fixed-plate-fitting groove (37), which is formed in an inner peripheral surface of a rear end thereof, and the fixed plate (60) may include a convex fixed-plate-fitting protrusion (62), which is formed on an outer peripheral surface thereof so as to correspond to the fixed-plate-fitting groove (37), the fixed plate (60) being forcibly fitted into the elastic-member-receiving portion (35) so as to be coupled thereto.
The push-member-sliding portion (31) of the housing (30) may include a protruding anti-rotation surface (33), and the guide part (71), which is slidably moved along an inner surface of the push-member-sliding portion (31), may include a rotation-blocking surface (71a) corresponding to the anti-rotation surface (33), whereby the push member (70) is slidable without being rotated.

[Advantageous Effects]

According to the present invention, since the stripping device, which is further provided to a cam unit for a mold, is able to efficiently return the cam slider and the punch, which have been used perform a punching operation on recent panels such as a high tension panel having increased tensile strength and a panel having increased thickness, so as to prevent the panel from being lifted along with the punch, thereby preventing defect and malfunction of products.
Furthermore, since the stripping device according to the present invention is able to be mounted on an existing punch holder and allows the push member to be easily dismantled or replaced in the state of being mounted on the punch holder, it is possible to improve the convenience of a mounting operation and efficiency in the production of products.
In addition, the disc springs, which are applied as the elastic member, allow realization of tensile strength higher than that of existing coil springs, and the fixed plate adapted to be forcibly fitted in the housing ensures stability of the stacked disc springs. Furthermore, since the stacked structure and the number of disc springs are controlled according to the kind of panel, it is possible to improve the efficiency of a punching operation using a mold.

[Description of Drawings]

FIG. 1 is a view showing a conventional cam unit for a mold before operation;
FIG. 2 is a view showing the conventional cam unit for a mold after operation;
FIG. 3 is an exploded view of a stripping device according to the present invention;
FIG. 4 is a cross-sectional view of a cam unit for a mold, to which the stripping device according to the present invention is applied;
FIG. 5 is a cross-sectional view showing an operation of the stripping device according to the present invention;
FIG. 6 is a cross-sectional view of an embodiment of the stripping device according to the present invention; and
FIG. 7 is a cross-sectional view of another embodiment of the stripping device according to the present invention.

[Best Mode]

A stripping device for a press mold according to the present invention has an improved structure designed to separate a panel from a punch when the punch is retracted rearwards after performing a punching operation using a press mold in order to prevent the panel from being lifted along with the punch, thereby improving productivity and the efficiency of a punching operation.
Hereinafter, the structure of a stripping device according to the present invention will be described in detail with reference to the accompanying drawings. The features of the present invention will be understood from the description.
The stripping device 100 according to the present invention is mounted on a punch holder 10 including a punch 16 in front of a cam slider 3 for a press mold. A housing 30 is provided therein with an elastic member 50 and a push member 70. In a punching operation, when the push member 70 comes into contact with a panel P, the push member 70 is pushed rearwards while the elastic member 50 is compressed against the elastic restoring force thereof. When the cam slider 3 is retracted rearwards after the punching operation, the push member 70 is pushed forwards by virtue of the restoring force of the elastic member 50, thereby preventing the panel P, which is in contact with the push member 70, from being lifted along with the punch 16.
To this end, the stripping device 100 according to the present invention is assembled in such a manner that a movable plate 40, the elastic member 50 and a fixed plate 60 are inserted into the cylindrical housing 30 in that order and the end of the housing 30 at which the inserted fixed plate 60 is positioned is pressed and narrowed inwards, thereby fastening the fixed plate 60 to the housing 30.
Referring to FIGS. 3 to 5, the housing 30 includes a push-member-sliding portion 31 and an elastic-member-receiving portion 35, which are formed in the inner peripheral surface thereof in a downward direction from above in the drawings. The housing 30 is provided on the outer peripheral surface thereof with a support flange 39, which projects outwards and has a fixing hole 39a, thereby enabling the housing 30 to be coupled to the front surface of the cam slider 30 by means of a fixing bolt.
Here, since the push-member-sliding portion 31 has a diameter smaller than that of the elastic-member-receiving portion 35 so as to define a stepped surface therebetween, the movable plate 40, which is received in the elastic-member-receiving portion 35, is blocked by the stepped surface, thereby restricting the movement of the movable plate 40.
The movable plate 40 is configured so as to have the same contour as that of the elastic-member-receiving portion 35 and to have a hole through which the punch 16 passes. Accordingly, the movable plate 40, which is inserted into the elastic-member-receiving portion 35, is blocked and supported by the stepped surface connected to the push-member-sliding portion 31.
Preferably, the elastic member 50 is embodied by tray-shaped disc springs, which are configured so as to have the same contour as that of the elastic-member-receiving portion 35 and to have a central hole through which the punch 16 passes and which are inserted into the housing 30 so as to be stacked to each other.
Even when the tray-shaped disc springs are inserted into the housing 30 and stacked therein, the foremost disc spring that contacts the movable plate 40 supports the peripheral portion of the movable plate 40 so as to stably support the movable plate 40, which is slid along the elastic-member-receiving portion 35, as illustrated in FIG. 4.
The fixed plate 60 is configured so as to have an outer diameter larger than the inner diameter of the elastic-member-receiving portion 35 and to have therein the central hole through which the punch 16 passes. Accordingly, the fixed plate 60 is fitted into the elastic-member-receiving portion 35 in an interference manner. The rear end of the housing is pressed and narrowed and is thus integrally coupled to the fixed plate 60.
Here, the holes (having no reference numeral), which are centrally formed in the movable plate 40, the elastic member 50 and the fixed plate 60, allow the punch 16 to pass therethrough without interfering with the components. A description of the holes is omitted.
In an embodiment in which the fixed plate 60 is forcibly fitted into the housing 30 and thus is integrally coupled thereto, the rear end of the elastic-member-receiving portion 35 is formed so as to have a fixed-plate-fitting groove 36 having a stepped portion, and the fixed plate 60 is fitted into the fixed-plate-fitting groove 36 and is mounted therein. Here, the outer peripheral surface of the fixed plate 60 is configured such that the front end thereof that is fitted into the elastic-member-receiving portion 35 has a diameter smaller than that of the rear end thereof, thereby defining an inclined surface 61.
Referring to FIG. 4, when the fixed plate 60 having the inclined surface 61, which is tapered toward the rear side from the front side fitted in the elastic-member-receiving portion 35, is fitted into the fixed-plate-fitting groove 36, the end of the housing 30, in which the inclined surface 61 is fitted, is simultaneously pressed inwards, with the result that the inclined surface 61 of the fixed plate 60 is integrally engaged with the inner peripheral surface of the fixed-plate-fitting groove 36.
In another embodiment in which the fixed plate 60 is forcibly fitted into the housing and thus is integrally coupled thereto, the rear end of the elastic-member-receiving portion 35 is provided in the inner peripheral surface thereof with a concave fixed-plate-fitting groove 37, and the fixed plate 60 is provided on the outer peripheral surface thereof with a convex fixed-plate-fitting protrusion 62 corresponding to the fixed-plate-fitting groove 37, as illustrated in FIG. 6. Consequently, the fixed plate 60 can be integrally coupled to the housing 30 by forcibly fitting the fixed plate 60 into the elastic-member-receiving portion 35. This embodiment also falls within the scope of the present invention.
Preferably, the elastic-member-receiving portion 35 is first formed such that the rear end thereof, which is positioned outside the fixed-plate-fitting groove 37, is widened radially outwards, and the fixed plate 60 is fitted into the fixed-plate-fitting groove 37 such that the fixed-plate-fitting protrusion 62 is positioned in the fixed-plate-fitting groove 37. Subsequently, the rear end of the housing 30 is pressed radially inwards such that the fixed-plate-fitting protrusion 62 is integrally engaged with the fixed-plate-fitting groove 37.
Each of the fixed-plate-fitting groove 37 and the fixed-plate-fitting protrusion 62 may be formed so as to have various sections, such as a "U" shape or a "V" shape. Here, it is essential to forcibly fit the fixed plate 60 into the housing 30, in the state in which the movable plate 40 and the elastic members 50 are received in the elastic-member-receiving portion 35 of the housing 30 so as to prevent separation of the movable plate 40 and the elastic members 50 from the housing 30.
In other words, after the movable plate 40 and the elastic members 50 are inserted into the elastic-member-receiving portion 35 of the housing 30 and are supported by the fixed plate 60, the push member 70 is slidably inserted along the push-member-sliding portion 31 connected to the elastic-member-receiving portion 35. Subsequently, a retaining ring 80 is fitted into the front end of the push-member-sliding portion 31 in order to prevent separation of the push member 70.
The push member 70 includes a guide part 71, which is centrally and longitudinally provided therein with a pin through hole 73 through which the punch 16 moves and which is slidably inserted into the push-member-sliding portion 31 from the front side so as to come into contact with the movable plate 40, and a projection part 72, which has a diameter smaller than that of the guide part 71 and which is integrally formed with the guide part 71. The projection part 72 is configured so as to project further outwards than the push-member-sliding portion 31.
Specifically, in order to prevent separation of the push member 70 in the initial state in which the guide part 71 of the push member 70 is inserted into the push-member-sliding portion 31 of the housing 30 and is supported by the movable plate 40, a ring-fitting groove 32 is formed in the inner peripheral surface of the push-member-sliding portion 31 in front of the guide part 71, and the retaining ring, which has an inner diameter smaller than the outer diameter of the guide part 71, is removably fitted into the ring-fitting groove 32, with the result that the guide part 71 of the push member 70 is blocked by the retaining ring 80, thereby preventing the push member 70 from being separated forwards.
The push-member-sliding portion 31 of the housing 30 is provided with a protruding anti-rotation surface 33, and the guide part 71 of the push member 70, which is slid along the inner surface of the push-member-sliding portion 31, is provided with a rotation-blocking surface 71a corresponding to the anti-rotation surface 33. Consequently, when the push member 70 is inserted into the housing 30, only the sliding movement of the push member 70 is allowed.
The housing, which includes the push-member-sliding portion 31, is further provided in the outer surface thereof with a tool-fitting groove 34 communicating with the ring-fitting groove 31. Consequently, the retaining ring 80 is conveniently separated from the ring-fitting groove 32 by inserting a tool into the tool-fitting groove 34 and lifting the retaining ring 80.
Although the retaining ring 80 is configured so as to have a circular section in this embodiment, a general snap ring 81 may also be used, as illustrated in FIG. 6. In this case, the ring-fitting groove 32 is configured so as to have a rectangular section corresponding to the cross section of the snap ring 81.
The stripping device 100 according to the embodiment of the present invention, which is constructed in the above-described manner, will be described with reference to FIGS 4 and 5 among the accompanying drawings. The support flange 39 of the housing 30 is first disposed on the punch holder 10, which includes the punch 16, and is coupled thereto by fastening a fixing bolt to the punch holder 10 through the fixing hole 39a.
At this time, the punch 16 extends through the fixed plate 60, the elastic members 50 and the movable plate 40 in the housing 30 and is disposed in the pin through hole 73 in the push member 70. When the punch holder 10 is moved forward for a punching operation, the projection part 72 of the push member 70 first comes into contact with the panel P.
When the punch holder 10 is moved further forwards, the projection part 72 of the push member 70 is pressed and moved rearwards by the panel P. At this time, when the movable plate 40 is pressed by the push member 70, the elastic members 50 are compressed against the elastic restoring force thereof, and the punch 16, disposed in the pin through hole 73, is projected outwards, thereby performing a punching operation on the panel P.
After completing the punching operation, the punch holder 10 and the housing 30, which are coupled to the cam slider 3, are retracted rearwards and are moved to the initial positions thereof, and thus the push member 70 is pushed forwards by the restoring force of the compressed elastic members 50.
In other words, as the movable plate 40 is moved forwards by the elastic restoring force of the elastic members 50, the guide part 71 of the push member 70 is slidably moved and is then blocked by the retaining ring 80, thereby blocking the movement of the push member 70.
Accordingly, when the cam slider 3 is retracted rearwards after the punching operation, the panel P, which would otherwise be lifted along with the punch 16 due to friction therebetween or the like, is pushed forwards, thereby ensuring reliable separation of the panel P.
The projection part 72 of the push member 70, which comes into contact with the panel, is made of a metal material softer than that of the panel P in order to prevent damage to the panel P. When the projection part 72 is worn out due to a punching operation for a prolonged period, the push member 70 has to be replaced with a new push member 70.
For the replacement operation, the cam slider 3 is first retracted rearwards such that the projection part 72 of the push member 70 is projected forwards from the housing 30. Thereafter, the retaining ring 80 is removed from the ring-fitting groove 32 using an additional tool.
Subsequently, the guide part 71 of the push member 70 is slidably moved forwards along the push-member-sliding portion 31 and is thus separated from the housing 30, and the guide part 71 of a new push member 70 is inserted along the push-member-sliding portion 31. Thereafter, the retaining ring 80 is fitted into the ring-fitting groove 32, thereby conveniently completing the replacement operation.

Claims

A stripping device (100) for a press mold, in which a punch holder (10) including a punch (16) is mounted on a front surface of an upper mold or a cam slider (3) for a press mold and in which a housing (30), which is provided therein with an elastic member (50) and a push member (70), is fixedly mounted on a front surface of the punch holder (10) such that the push member (70) is compressed against restoring force when contacting an object to be punched, the stripping device (100) comprising:
the housing (30), which includes a push-member-sliding portion (31) and an elastic-member-receiving portion (35), which are continuously formed in an inner cylindrical surface thereof toward a rear side from a front side, the housing (30) further including a support flange (39) having a fixing hole (39a), which is formed in an outer peripheral surface of a rear end thereof so as to be coupled to the front surface of the punch holder (10) by means of a bolt;

a movable plate (40), which is inserted into the elastic-member-receiving portion (35) from the rear side and is blocked by a stepped portion formed between the elastic-member-receiving portion (35) and the push-member-sliding portion (31), the movable plate (40) having formed therein a central hole through which the punch (16) passes;

the elastic member (50) having formed therein a central hole through which the punch (16) passes, the elastic member (50) being inserted into the elastic member-receiving member (35), and the elastic member (50) being compressed when the movable plate (40) is moved along the elastic-member-receiving portion (35);

a fixed plate (60) having formed therein a central hole through which the punch (16) passes, the fixed plate (60) being inserted into an inner peripheral surface of the elastic-member-receiving portion (35) through a rear open end of the elastic-member-receiving portion (35) and then being coupled to the rear end of the housing (30) by pressing the rear end of the housing (30) inwards;

the push member (70) including a guide part (71) provided at a rear side thereof, which is slidably inserted into the push-member-sliding portion 31 from the front side of the housing (30) and which comes into contact with the movable plate (40), and a projection part (72) provided at a front side thereof, which has a diameter smaller than that of the guide part (71), the push member (70) including a longitudinal pin through hole (73) through which the punch (16) is moved; and

a retaining ring (80), which is removably fitted into a ring-fitting groove (32) formed in an inner peripheral surface of a front end of the push-member-sliding portion (31) so as to prevent the guide part (71) of the push member (70) from being moved forwards.
The stripping device according to claim 1, wherein the fixed plate (60) is fitted into a fixed-plate-fitting groove (36), which is formed in a rear end of the elastic-member-receiving portion (35) so as to have a stepped portion, and wherein the fixed plate (60) is provided on an outer peripheral surface thereof with an inclined surface (61), which has a smaller diameter at a rear end thereof than at a front end thereof, and is forcibly fitted into the rear end of the housing (30) so as to be integrally coupled to the housing (30).
The stripping device according to claim 1, wherein the elastic-member-receiving portion (35) includes a concave fixed-plate-fitting groove (37), which is formed in an inner peripheral surface of a rear end thereof, and the fixed plate (60) includes a convex fixed-plate-fitting protrusion (62), which is formed on an outer peripheral surface thereof so as to correspond to the fixed-plate-fitting groove (37), the fixed plate (60) being forcibly fitted into the elastic-member-receiving portion (35) so as to be coupled thereto.
The stripping device according to claim 1, wherein the push-member-sliding portion (31) of the housing (30) includes a protruding anti-rotation surface (33), and the guide part (71), which is slidably moved along an inner surface of the push-member-sliding portion (31), includes a rotation-blocking surface (71a) corresponding to the anti-rotation surface (33), whereby the push member (70) is slidable without being rotated.