EP3912746B1

EP3912746B1 - Tandem press line and intermediate feeding device

Info

Publication number: EP3912746B1
Application number: EP21174487.5A
Authority: EP
Inventors: Kenichi Endo
Original assignee: Aida Engineering Ltd
Current assignee: Aida Engineering Ltd
Priority date: 2020-05-21
Filing date: 2021-05-18
Publication date: 2023-01-11
Anticipated expiration: 2041-05-18
Also published as: EP3912746A1; JP2021183346A; JP7312725B2; CN113695454A

Description

BACKGROUND OF THE INVENTION

Filed of the invention

The present invention relates to a tandem press line and an intermediate feeding device. Particularly, it relates to a tandem press line in which two press machines performing punching are arranged in tandem arrangement.

Description of the Related Art

Patent Document 1 discloses a laminated core punching device in which a rotor punching press machine and a stator punching press machine are arranged in tandem arrangement. In this device, the two press machines are operated synchronously by directly coupling the crankshafts thereof. Therefore, there is no need to provide an accumulator between both the press machines to absorb the difference between the stopping timings and/or between the operating speeds. Patent Document 1 further discloses an intermediate loop portion for adjusting the coil strip length between the press machines to the die pitch during the die replacement.
The paragraph [0009] in Patent Document 2 discloses a tandem line of a punching press machine in which an automatic feeding device for intermittently feeding a coil strip fed by a leveler at a predetermined rate is arranged before and after two press machines so as to be sandwiched therebetween. To adjust the die pitch and the feeding center, a technique is disclosed in which a press machine is installed in a position-adjustable manner back and forth (in the width direction of the coil strip) or left and right (in the feeding direction of the coil strip).
Patent Document 3 discloses that in a tandem press line in which each processing, such as, e.g., drawing, trimming, piercing, and cutting, is performed by one press machine, a press pitch adjustment device for adjusting the distance between press machines is provided.
US 2020/094307 A1 discloses the features of the preamble of claim 1.

Prior Art Document

Patent Document

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-205836
Patent Document 2: Japanese Unexamined Patent Application Publication No. H09-108898
Patent Document 3: Japanese Unexamined Patent Application Publication No. 2009-233673

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In the tandem press line of Patent Document 1, since an intermediate loop portion is provided to adjust the material length between press machines, the feeding path of the material is greatly curved. In addition, two feeding devices are provided for each press machine, i.e., a total of four feeding devices (feeders 51 to 54) are provided, thereby increasing the entire size of the system, which increases the line length. Therefore, the transferring mass of the material is also large.
In the tandem press line of Patent Document 2, only one feeding device (automatic feeding device 30) is provided for two press machines, and no intermediate loop portion is required, so the line length can be shortened. However, the operation timing of the two press machines must coincide with the operation timing of the feeding device, and therefore a high-speed operation cannot be supported. In the tandem press line of Patent Document 3, each processing, such as, e.g., drawing and punching, is performed with one press machine. Therefore, it is difficult to perform a high-speed operation.
An object of the present invention is to provide a tandem press line and an intermediate feeding device used in the tandem press line capable of shortening a line length, easily adjusting a coil strip length of pressing when replacing a die, and performing a high-speed operation,.

Means for Solving the Problem

An intermediate feeding device 50 according to the present invention is a device to be provided between a first press machine 11 and a second press machine 12, and is configured to feed the coil strip W coming out from the first press machine 11 to the second press machine 12. The intermediate feeding device 50 is provided with a first feeding line guide 52 and a second feeding line guide 53 each configured to support the coil strip W at a feeding line height H, the first feeding line guide 52and the second feeding line guide 53 being arranged at two positions on an upstream side and a downstream side in a line feeding direction of the intermediate feeding device , respectively; a pair of upper and lower feeding rolls 51b and 51a configured to guide the coil strip W so that the coil strip W passes through an detour path shifted in a vertical direction with respect to the feeding line height H when feeding the coil strip W, the pair of upper and lower feeding rolls 51b and 51a being arranged between the first feeding line guide 52 and the second feeding line guide 53; and a release mechanism 55 configured to release the feeding rolls 51b and 51a after completion of feeding the coil strip W so that the coil strip W is released before being positioned with respect to a die. Note, the above-mentioned "line feeding direction" means a direction in which a coil strip flows from upstream to downstream in a tandem press line.
A tandem press line 10 according to the present invention includes a first press machine 11 configured to punch a coil strip W fed intermittently, a second press machine 12 configured to further punch the coil strip W coming out from the first press machine 11, in synchronization with the first press machine 11, and the intermediate feeding device mentioned above.
In the tandem press line 10, it is preferable that a crankshaft 17 of the first press machine 11 and a crankshaft 17 of the second press machine 12 are coupled to each other so as to be synchronously rotated. Further, the tandem press line is preferably provided with a distance adjustment mechanism 13 configured to adjust a distance in a line feeding direction between the first press machine 11 and the second press machine 12 .
Further, it is preferable that the tandem press is provided with a press distance adjustment mechanism 13 configured to adjust a distance between the first press machine 11 and the second press machine 12 in a line feeding direction, and a crankshaft 17 of the first press machine 11 and a crankshaft 17 of the second press machine 12 are coupled via a coupling 28 that allows movement in an axial direction.
Further, it is preferable that the press distance adjustment mechanism 13 is provided with a supporting device 21 configured to support either one or both of frames 16, 16 of the first press machine 11 and the second press machine 12 in a movable manner in a coil strip feeding direction, a motor-driven movement drive mechanism 25 configured to connect both the frames 16, a sensor 26 configured to detect a distance between a die 40 (40a, 40b) installed on the first press machine 11 and a die 40 (40a, 40b) installed on the second press machine 12, and a control device C configured to perform control of driving the movement drive mechanism 25 so that a detected value of the sensor 26 coincides with a distance predetermined for each die 40.

Effects of the Invention

In the intermediate feeding device, when the coil strip is drawn into the die before the press machine performs punching, the drawn amount is compensated by the coil strip passing through the detour path shifted from the feeding line height in the vertical direction. Therefore, it does not cause a problem, such as, e.g., a deformation due to forcible tension of the coil strip. Moreover, when feeding the coil strip, the intermediate feeding device guides the coil strip in an almost straight manner, so that it can be fed smoothly with less transferring mass.
In a specific example, in the case of progressive processing, after completion of feeding the coil strip by the feeding device before the positioning of the coil strip with respect to the die, the pilot pin provided in the die installed on the first press machine or in the upper die of the die installed on the first press machine or the second press machine is fitted in the positioning hole punched in the coil strip in a first step, so that the coil strip is positioned with respect to the lower die of the die. The above-described "after completion of feeding...before the positioning of the coil strip with respect to the die" means a period from the completion of feeding the coil strip by the feeding roll of the intermediate feeding device until the completion of positioning the coil strip to the die.
The feeding device releases the feeding roll before the coil strip is positioned to make the coil strip in a free state to prevent the positioning by the pilot pin. After being positioned, the coil strip is pushed down by the stripper plate provided at the upper die prior to the punching by the press machine. Therefore, the coil strip is pressed against the upper surface of the die plate of the lower die while being drawn into the die, and punching is performed in that state. After completion of the punching, the stripper plate and the pilot pin are separated sequentially from the coil strip, and the feeding device clamps the coil strip that has become free again with the feeding rolls to begin feeding.
In the tandem press line of the present invention, since the intermediate feeding device is equipped, the effects to be obtained by the intermediate feeding device can be obtained.
In the tandem press line, in a case where the crankshaft of the first press machine and the crankshaft of the second press machine are coupled to each other so as to be synchronously rotated, the synchronicity of the synchronizing operation of the two press machines is high.
In the tandem press line, in a case where the press distance adjustment mechanism for adjusting the distance in the line feeding direction between the first press machine and the second press machine is provided, it is possible to facilitate the adjustment of the length of the coil strip between the press machines when replacing a die. Therefore, it is not necessary to provide an intermediate loop portion as described in Patent Document 1. Accordingly, the line length can be shortened by that amount.
In such a tandem press line, in a case where the press distance adjustment mechanism is provided with: a supporting device configured to support either one or both of the first press machine and the second press machine in a movable manner in a line feeding direction; a motor-driven expansion/contraction drive mechanism configured to connect both the frames; a sensor configured to detect a distance between a die installed on the first press machine and a die installed on the second press machine, and a control device configured to perform control of driving the movement (expansion/contraction) drive mechanism so that a detected value of the sensor coincides with a distance predetermined for each die, the distance between the die of the first press machine and the die of the second press machine can be adjusted correctly and easily. Therefore, the line downtime associated with a die replacement can be shortened, enabling an efficient line operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing one example of a tandem press line relating to the present invention.
FIG. 2 is a plan view including a block diagram of the control system of the tandem press line of FIG. 1.
FIG. 3 is a structural diagram showing one example of a punching die.
FIG. 4 is a schematic explanatory view showing the difference in the material height between during the transferring and during the processing in the tandem press line.
FIG. 5 is a schematic explanatory view showing the relation between the material length during the transferring and during the processing.
FIG. 6 is a structural explanatory view showing an example of a feeding device of the present invention.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

The tandem press line 10 shown in FIG. 1 is provided with a first press machine 11, a second press machine 12, and a press distance adjustment mechanism 13 for adjusting the distance between both the press machines 11 and 12. In addition, on the upstream side of the tandem press line 10, the coil supply device 14 for supplying the coil strip W to the line is arranged. This tandem press line 10 is for punching the coil strip W by the dies 40 and 40, and in particular, can continuously produce a lamination motor core and the like at high speed. In that case, the first press machine 11 sequentially performs a plurality of punching processing in the coil strip W, and finally performs the outer shape punching and lamination to produce a rotor of a motor. The second press machine 12 performs punching processing several times and outer shape punching/lamination on the remaining portion of the coil strip W used in the first press machine 11 to produce a stator.
The first press machine 11 includes a frame 16 fixed to a floor via a base 15, a crankshaft 17 provided in rotatable manner at the upper portion of the frame 16, two connecting rods 18 attached to the crankshaft 17, a slide 20 suspended by the connecting rods 18 and vertically guided by the frame 16, a bolster 16a attached to the frame 16, etc. The connecting rods 18 and the slide 20 are connected via a plunger (not shown), and the slide 20 is stroked in the vertical direction in accordance with the rotation of the crankshaft 17. In the die 40, the lower die 40a is fixed to the bolster 16a, and the upper die 40b is fixed to the slide 20. The upper die 40b is stroked in the vertical direction in accordance with the stroke of the slide 20.
The type of the press machine is a so-called high-speed automatic press suitable for high-speed blanking. As an example, the press machine is equipped with a high rigidity frame that withstands punching of a silicon steel sheet at a stroke of 10 mm to 30 mm and a speed of 200 spm to 300 spm, a pre-compressed precision slide guide, etc. The base 15 has a built-in vibration proof mechanism.
Between the frame 16 and the base 15 of the second press machine 12, a supporting device 21 equipped with a plurality of rolls supporting the load of the press machine is interposed. The frame 16 is supported in a movable manner in the line feeding direction with respect to the base 15 (in the left and right direction in FIG. 1). In the first press machine 11, a spacer block 22 of the same height is interposed in place of the supporting device 21 in order to standardize the press machine specification. Since the other portions of the second press machine 12 are substantially the same as those of the first press machine 11, the same symbol will be allotted and the explanation thereof will be omitted. The left and right supporting devices 21 of the second press machine 12, and the left supporting device 21 and the spacer block 22 of the first press machine 11 are connected to each other by the connection rods 21a and 22a, respectively, in order to prevent the base 15 from shifting by the lateral direction load due to the frictional resistance generated between the frame 16 and the base 15 when the frame 16 is moved.
Between the frame 16 of the first press machine and the frame 16 of the second press machine 12, an expansion/contraction (movement) drive mechanism 25, for example, composed of a screw 23 and a nut 24 is interposed. In the embodiment of FIG. 1 and FIG. 2, a screw 23 is fixed to the second press machine 12, and a nut 24 screwed with the screw 23 is rotatably held by a nut holder 25a to the first press machine 11 so as not to move in the axial direction. The nut 24 is rotatably driven by a motor, such as, e.g., a servo motor (not shown). The expansion/contraction drive mechanism 25 is controlled by a control device C of FIG. 2. The control device C is configured by a control unit Ca for controlling the rotation of the motor, a calculation unit Cb for calculating the expansion/contraction quantity, a storage unit Cc for storing arithmetic expressions and data, a setting unit Cd for setting an initial value, a display unit Ce, etc.
In making the distance L between the die in the first press machine 11 and the die in the second press machine 12 coincide by the movement drive mechanism 25 with a distance predetermined for each set of dice, the following is assumed. Note that the distance described below denotes a distance in the feeding direction of the coil strip W.
In the coil strip W, a positioning hole is punched in the first step of the first press machine 11. Then, the coil strip W is positioned relative to the lower die 40a by fitting the pilot pin Pp of the upper die 40b into the processed positioning hole. Therefore, in the tandem press line 10 in which the coil strip W is transferred in a substantially straight manner in the feeding direction to progressive processing, it is possible to set the distance between the dies to a center distance (L in FIG. 2) between the pilot pin Pp1 located at the most downstream side of the die 40 installed in the first press machine 11 and the pilot pin Pp2 located at the most upstream side of the die installed in the second press machine 12. Further, the distance L predetermined for each die is the center distance between the pilot pins Pp adjacent in the feeding direction of the coil strip W in each die, i.e., a distance of the integral multiple of the feeding pitch P. Further, it is preferable to determine the minimum distance Fmin in which each device (e.g., the first press machine 11 and the second feeding device 37) does not interfere with each other by the integral multiple of the center distance of the pilot pins Pp.
A sensor 26 for detecting the press installation distance (F in FIG. 2) is provided between the first press machine 11 and the second press machine 12. This sensor 26 detects, for example, the distance F between the sides of the adjacent frames 16 of the first press machine 11 and the second press machine 12.
FIG. 2 shows a plan view of the tandem press line 10 of FIG. 1 together with the control device C. As shown in FIG. 2, the electronic tags Tg1 and Tg2 in which die data is recorded are attached to the dies 40 and 40 installed in the first press machine 11 and the second press machine 12, respectively. The first press machine 11 and the second press machine 12 are provided with an antenna AT1 and an antenna AT2 each for receiving a wireless signal originating from the electronic tag Tg1 and the electric tag Tg2 and a receiver R1 and a receiver R2 each for transmitting the received signal to the control device C, respectively.
The information recorded in the electronic tag Tg1 and Tg2 includes the installation position of the die 40, 40 with respect to the press machine 11, 12, the arranged positions of the pilot pins Pp and Pp1, Pp2, and the information on the feeding pitch P. Further, various information is stored in the storage unit Cc. The information includes, for example, the distance from the center of each press machine 11, 12 to the mounting position (E1, E2 of FIG. 2) of the sensor 26 inputted from the setting unit Cd of the control device C, the minimum distance (Fmin in FIG. 2) in which the devices do not interfere at the time of adjusting the press installation distance F, and the current press installation distance F detected by the sensor 26.
When the die 40, 40 is carried into the press machine 11, 12, first, the information on the electronic tag Tg1, Tg2 is wirelessly read by the receiver R1, R2 (via the antenna AT1, AT2) and transmitted to the control device C. When installing on the bolster 16a of the press machine 11, 12, the die 40, 40 is installed at the position determined for each die 40 by the positioning pin 21p of the die provided on the bolster 16a side. Next, based on the information read from the electronic tag Tg1, Tg2 and the information stored in the storage unit Cc, the center distance (L in FIG. 2) between the pilot pin Pp1 located at the most downstream side of the die 40 installed in the first press machine 11 and the pilot pin Pp2 located at the most upstream side of the die installed in the second press machine 12 is calculated by the calculation unit Cb.
The calculation unit Cb further calculates the minimum distance Fmin that does not cause interference of the devices and is the integral multiple of the feeding pitch P of the coil strip W from the calculated center distance L between the pilot pins Pp1 and Pp2 and outputs the calculation result to the control unit Ca. Depending on the calculation result, the control unit Ca drives the motor of the expansion/contraction drive mechanism 25 to adjust the press installation distance F. Alternatively, in order to provide some margin in the length of the coil strip W, the press installation distance F is set to the minimum distance Fmin which is a distance somewhat shorter than the distance of the integral multiple of the feeding pitch P and does not cause the interference of the devices.
According to this embodiment, even in cases where there is an obstacle, such as, e.g., a feeding device, between the die 40 and the die 40, and therefore it is difficult to directly measure the center distance L between the pilot pins Pp1 and Pp2 or the distance between the dies, it is possible to easily cope with that. In this embodiment, the information on the electronic tag Tg1, Tg2 is read by utilizing radio, but the information may be read by a reading device using a bar code or a two-dimensional bar code instead of the electronic tag.
The supporting device 21, the expansion/contraction drive mechanism 25, and the sensor 26 constitute the press distance adjustment mechanism 13 as a whole. The press distance adjusting mechanism 13 is operated every time the die is replaced according to the motor core to be manufactured. By activating the press distance adjustment mechanism 13 during the press operation, it is also possible to absorb the change in the press installation distance F by the thermal expansion of the frame 16 due to the friction heat caused by the high-speed operation.
The right edge of the crankshaft 17 of the first press machine 11 (the downstream side in the line feeding direction) and the left edge of the crankshaft 17 of the second press machine 12 (the upstream side in the line feeding direction) are coupled via a coupling 28 which ensures the synchronous rotation between the crankshafts 17 and 17. This coupling 28 is designed to transmit torque while allowing the movement of the second press machine 12 in the line feeding direction, for example, a spline coupling in which a spline shaft and a spline nut are connected in an axially slidable manner. In addition, as the coupling 28, an Oldham's coupling that absorbs the axial misalignment or inclination, or a coupling in which universal joints are combined may be used.
At each of the other ends of the crankshafts 17 and 17 of the first press machine 11 and the second press machine 12, a rotation driving source, such as, e.g., an electric motor (not shown), is connected. The electric motors are synchronously controlled. The electric motor is an induction motor. However, the electric motor is not limited to an induction motor, and may be a DC motor, an AC servomotor, a DC servomotor, etc.
The coil supply device 14 is provided with an uncoiler 30 for holding a coiled material and feeding the coil strip W by rotating or by being freely rotated in accordance with the pulling out of the coil strip W, a leveler 31 for correcting the curl of the coil strip W fed out of the uncoiler 30 to flat it, and a looping control 32. The uncoiler 30 is provided with a motor (not shown) for rotatably driving the supporting shaft on which the coil strip W is mounted in the forward and reverse direction. The leveler 31 is provided with motor-driven pinch rolls 31a for feeding the coil strip W. The looping control 32 is for forming a loop of the coil strip W for absorbing the difference between the intermittent feeding in the press machines 11 and 12 and the continuous feeding by the uncoiler 30 and the leveler 31, and for adjusting the material feed rate of the uncoiler 30 and the leveler 31 when the loop becomes larger than a predetermined value and becomes conversely smaller than a predetermined value.
The uncoiler 30 is provided with a coil press 30a which prevents the loosening of the coil. The symbol 30b denotes a coil outer diameter measurement device equipped with a sensor for detecting a coil outer diameter. Based on the output of the coil outer diameter measurement device, the control device (not shown) controls to increase the rotation speed of the supporting shaft of the uncoiler 30 as the remaining amount of the coil is reduced so that the length of the coil strip W to be fed coincides with the command value of the feeding length of the feeding device. The coil press 30a may be provided with a coil rotation drive roll. In this case, the rotation speed of the drive roll does not need to be changed depending on the coil diameter. The symbol 33 is a pair of upper and lower guide plates defining the feeding path of the coil strip W.
The symbol 34 denotes an auxiliary feeding device provided with a pair of upper and lower rolls sandwiching the coil strip W, a motor (not shown) for driving the roll, and an encoder (not shown) for detecting the rotation of the roll. The auxiliary feeding device 34 also serves as a back stop roll for performing the threading for leading the tip end portion of the coil strip W to any predetermined position and the checking of the feeding length of the coil strip W and preventing the return of the coil strip W. Further, the auxiliary feeding device 34 may include a function of monitoring the speed of the coil strip W, or correcting the feeding length by each feeding device 36, 37, and 38 by measuring the movement amount when the coil strip W is pulled into the die prior to being subjected to punching processing.
In the tandem press line 10 of FIG. 1, on the upstream side (left side) of the frame 16 of the first press machine 11 and on the downstream side (left side) and the upstream side (right side) of the second press machine 12, a first feeding device 36, a second feeding device 37, and third feeding device 38 for pinching and intermittently feeding the coil strip W with the upper and lower rolls in accordance with the operation of the press machines 11 and 12. The feeding devices 36, 37, and 38 are set to feed the coil strip W along the feeding line FP. The upper surfaces of the lower rolls 36a, 37a, and 38a coincide with the feeding line height H. Usually, the lower rolls 36a, 37a, and 38a are rotatably driven to feed the coil strip W.
On the other hand, the upper rolls 36b, 37b, and 38b are driven to be moved up and down in response to the signal from the control device to be lowered when feeding the coil strip W to pinch the coil strip between the upper roll and the lower roll, and to be lifted when performing pressing to release the coil strip W or make a tip of the coil strip W easily pass through the line in order to preparation for stamping. Note that the upper and lower rolls may be configured to be freely rotated to release (freely pull out) the coil strip W. Further, it may be configured such that a motor for driving the coil strip W is provided only at the second feeding device 37, and the first feeding device 36 and the third feeding device 38 serve only for guiding the coil strip W, i.e., are freely rotated. The symbol 39 on the downstream side of the third feeding device 38 denotes a scrap cutter for cutting the coil strip W (scrap) in which the product has been removed to a constant length.
The tandem press line 10 of FIG. 1 is provided with a press distance adjustment mechanism 13 for adjusting the distance between the first press machine 11 and the second press machine 12. Therefore, it is possible to adjust the length of the coil strip W between the press machines 11 and 12 to the integral multiple of the feeding pitch P by adjusting the distance between the press machines 11 and 12 at the time of replacing the die. Therefore, it is not necessary to provide an intermediate loop portion as disclosed in Patent Document 1. Accordingly, the line length can be shortened by that amount. Further, since no intermediate loop portion is provided, even if the first press machine 11 and the second press machine 12 are relatively large, the distance between the ends of the crankshafts 17 and 17 is small. Therefore, it is easy to connect them directly. Further, since the connection is made via the coupling 28 that allows the movement in the axial direction, the adjustment of the distance between the press machines 11 and 12 by the press distance adjustment mechanism 13 is not hindered.
Furthermore, since the distance between the press machines 11 and 12 is small, it is possible to make the downstream side feeding device of the first press machine 11 and the upstream side feeding device of the second press machine 12 into one feeding device (second feeding device 37). As a result, the equipment cost can be reduced, and the line length can be further reduced.
Next, referring to FIG. 3 to FIG. 6, a preferred embodiment of the feeding device will be described. FIG. 3 shows an example of a punching die used in the tandem press line 10 shown in FIG. 1. The left half shows the state when the press machine is at rest or when the material is being transferred, and the right half shows the state when the material is being processed. The punching die 40 is composed of a lower die 40a and an upper die 40b. The lower die 40a is composed of a base 41, a lower die plate 42 provided thereon, a spring 44 for upwardly urging a material lifter 45 housed in the hole 43 of the base 41, and the material lifter 45 slidably fitted in the through-hole 42a formed in the die plate 42.
At the lower end of the material lifter 45, a flange 45a is provided. The flange 45a is configured to regulate the rising end of the material lifter 45 by bringing the upper surface of the flange 45a into contact with the lower surface of the die plate 42. The lower surface of the flange 45a is in contact with the spring 44. At the vicinity of the upper end of the material lifter 45, an annular groove 45b for slidably guiding the side edge of the coil strip W is formed. The material lifter 45 may be provided in a freely rotatable manner about its own axis.
The material lifter 45 is configured, when transferring the coil strip W, to hold the coil strip W in a position lifted slightly (e.g., about 10 mm) from the lower die surface to avoid the contact between the coil strip W and the lower die surface. Thus, the coil strip W is lifted up somewhat (e.g., about 10 mm) than the lower die 40a to be transferred along the feeding line FP.
The upper die 40b has a base 46, a punch 47, a stripper plate 48, and a spring 49 which biases the stripper plate 48 downward. In the die plate (dies) 42 of the lower die 40a, a through-hole 42b of the same shape as the punched piece or a through-hole 42b of the same shape as the contour of the core (a rotor or a stator) to be punched from the coil strip W. The punch 47 of the upper die 40b is fitted in the through-hole 42a to perform the punching operation of the coil strip W. The stripper plate 48 is intended to peel off the coil strip W from the punch 47 of the upper die 40b and is provided at the lower surface with a hole 47a for housing the upper portion of the material lifter 45.
Therefore, as shown in the right side of FIG. 3, at the time of processing the material, the stripper plate 48 presses down the coil strip W on the upper surface of the die plate 42 and pushes down the material lifter 45. Therefore, as shown by the imaginary line shown in FIG. 4 and FIG. 5, the coil strip W is held straight along the feeding line FP at the time of the transferring and is pushed down to the height (processing height) Ho of the upper surface of the lower die 40a lower than the feeding line height H as shown by the solid line at the time of the processing. In this case, at the first to third feeding devices 36 to 38, the feeding line height H is maintained as it is. In the range in which the coil strip W is pinched by the dies 40a and 40b, it is pushed down by the lifting amount of the material lifter 45. Therefore, in the sections S 1 and S2 between them, the coil strip W is inclined and bends into a generally flat V-shape or inverted trapezoidal shape. Since it passes through a somewhat longer path compared with the straight form (imaginary line) at the time of the transferring, the upstream side and the downstream side of the coil strip W in the area sandwiched by and between the dies 40a and 40b will be drawn by the difference in the length of the path.
Note that during the processing, the upper rolls 36b, 37b, and 38b of the feeding devices 36 to 38 are lifted to release the coil strip W. Therefore, the coil strip W is drawn from the upstream side of the first press machine 11 and the downstream side of the second press machine 12 as shown by the arrow R in FIG. 4, so that the difference in the length of the path is compensated. However, since the first press machine 11 and the second press machine 12 are operated synchronously, and the processing is performed simultaneously, there is no extra material that can be retracted in the vicinity of the second feeding device 37. Therefore, it is impossible to compensate for the difference in the path. For this reason, in the vicinity of the second feeding device 37, the coil strip W is pulled from both sides to be extended. Here, the coil strip W present at this location has been subjected to processing by the die of the first press machine 11, so that there are a large number of holes. Thus, it is in an easily deformable state by an external force. So, if the processed coil strip W is pulled from both sides in such a condition to be extended, deformation or pitch offset may occur. In a case where the positioning hole of the coil strip W is deformed or offset in the pitch, when inserting the pilot pin Pp of the die of the second press machine 12 into the positioning hole, the pilot pin Pp is forcibly inserted therein, causing a further deformation of the periphery of the positioning hole. Consequently, the feeding pitch of the coil strip W may become inaccurate, resulting in misfeeding or a defective product.
FIG. 6 shows a second feeding device (intermediate feeding device) capable of solving the above-described problems. In this intermediate feeding device 50, on the upstream side and the downstream side in the line feeding direction of the pair of upper and lower feeding rolls 51 (the lower roll 51a and the upper roll 51b), first and second feeding line guides 52 and 53 for supporting the coil strip W to the feeding line height H are arranged. The upper surface of the lower roll 51a is positioned at a position lower than the feeding line height H. To transfer the coil strip W, usually, the lower roll 51a is driven by a motor M1, particularly a servo motor, but the upper roll 51b or both the lower roll 51a and the upper roll 51b may be driven. The feeding line guide 52, 53 is composed of upper and lower guide plates 52a1, 52a2, 53a1, 53a2 having a gap through which the coil strip W can pass and a guide roll 52b, 53b rotatably supported to support the lower surface side of the coil strip W.
In the intermediate feeding device 50, the supporting shaft of the upper roll 51b is provided in a vertically movable manner with respect to the housing and is driven so as to move up and down by the lifting and lowering drive mechanism 55 and press the upper roll 51b to the lower roll 51a when the upper roll 51b is lowered. The lifting and lowering drive mechanism 55 can be configured by a motor M2, particularly a servo motor, and a screw mechanism. It can also be driven by an air cylinder or the like. When transferring the coil strip W, the coil strip W is sandwiched by the upper roll 51b and the lower roll 51a and the lower roll 51a is rotated by a motor M1 in the clockwise direction in FIG.6 so that the coil strip W is fed from the upper stream side to the downstream side in the line. During the processing by the press machine, it is possible to release the coil strip W by lifting the upper roll 51b. In this case, contrary to the case shown in FIG. 5, at the time of being transferred, the coil strip W passes through a substantially V-shaped path indicated by the solid line, and at the time of being processed by the press machine, the coil strip W extends straight along the feeding line FP as indicated by the imaginary line. Therefore, the material can be compensated by the difference between the paths to the dies 40a and 40b at the time of the processing, which can prevent the coil strip W being excessively stretched.
The inclined angle θ of the path during the above-described transferring becomes larger as the distance between the guide roll 52b, 53b and the feeding roll 51 becomes increases and becomes smaller as the distance between the guide roll 52b, 53b and the feeding roll 51 decreases. Therefore, the difference between the paths becomes larger as the distance between the guide roll 52b, 53b and the feeding roll 51 decreases and becomes smaller as the distance between the guide roll 52b, 53b and the feeding roll 51 increases. Therefore, by setting the distance between the guide roll 52b, 53b and the feeding roll 51 to be shorter than the section S 1, S2 in which the material becomes oblique due to the retraction of the material by the die, the release quantity of the feeding roll 51 can be made smaller than the difference between the feeding line height H and the height of the upper surface (processing forming height) Ho of the lower die 40a during the transferring.
In view of the above, it is preferable to provide an adjustment mechanism for adjusting the position of the guide roll 52b, 53b in the horizontal direction. Further, the lower the position of the lower roll 51a of the feeding roll 51 is, the larger the inclination angle θ during the transferring is. Thus, the difference in the path increases. For this reason, a mechanism for adjusting the height of the lower roll 51a may be provided. However, in either case, the radius of curvature of the coil strip W is set within the elastic deformation of the coil strip W.
The intermediate feeding device 50 of FIG. 6 can be used as the second feeding device 37 in the tandem press line 10 in FIG. 1 or the second feeding device 37 in the tandem press line in FIG.5.
While the preferred embodiment has been described above, the present invention is not limited to these embodiments, and any changes can be made within the scope of the present invention as defined by the appended claims. For example, in the intermediate feeding device shown in FIG. 6, the detour path is provided below the feeding line height H, but it is possible to provide the detour path by the feeding roll shifted upward.

Description of Symbols

10:: Tandem press line
11:: First press machine
12:: Second press machine
13:: Press distance adjustment mechanism
14:: Coil supply device
W:: Coil strip
15:: Base
16:: Frame
16a:: Bolster
17:: Crankshaft
18:: Connecting rod
20:: Slide
21:: Supporting device
21a:: Connection rod
21p:: Positioning pin of die
22:: Spacer block
22a:: Connection rod
23:: Screw
24:: Nut
25:: Movement (Expansion/contraction) drive mechanism
25a:: Nut holder
26:: Sensor (detecting press installation distance)
28:: Coupling
30:: Uncoiler
30a:: Coil press
30b:: Coil outer diameter measurement device
31:: Leveler
31a:: Pinch roll
32:: Looping control
33:: Guide plate
34:: Auxiliary feeding device
36:: First feeding device
37:: Second feeding device
38:: Third feeding device
36a, 37a, 38a:: Lower roll
36b, 37b, 38b:: Upper roll
40:: Die
40a:: Lower die
40b:: Upper die
Tg1:: Electronic tag of die installed on first press machine
Tg2:: Electronic tag of die installed on second press machine
AT1, AT2:: Antenna
R1, R2:: Receiver
A1, A2:: Mounting position for press machine
B1, B2:: Position information at the center of pilot pin
E1, E2:: The distance from the center of press machine to mounting position of sensor
F:: Distance between press installation
Fmin:: Minimum distance between press installation
C:: Control device
Ca:: Control unit
Cb:: Calculation unit
Cc:: Storage unit
Cd:: Setting unit
Ce:: Display uint
P:: Feeding pitch
Pp:: Pilot pin
Pp1:: The most downstream pilot pin of die of first press machine
Pp2:: The most upstream pilot pin of die of second press machine
L:: Center distance between the most upstream pilot pin and the most downstream pilot pin
41:: Base (lower die)
42:: Die plate
42a, 42b:: Through-hole
43:: (Base) hole
44:: Spring
45:: Material lifter
45a:: Flange
45b:: Annular groove
46:: Base (upper die)
47:: Punch
47a:: Hole
48:: Stripper plate
49:: Spring
FP:: Feeding line
H:: Feeding line height
Ho:: Lower die top height
50:: Intermediate feeding device
51:: Feeding roll
51a:: Lower roll
51b:: Upper roll
52, 53:: Feeding line guide
52a1, 52a2, 53a1, 53a2:: Guide plate
52b, 53b:: Guide roll
M1:: Motor (feeding roll)
M2:: Motor (lift mechanism)
S1, S2:: Diagonal section
55:: Lifting and lowering mechanism

Claims

An intermediate feeding device (50) to be provided between a first press machine (11) and a second press machine (12), the intermediate feeding device (50) being configured to feed the coil strip W coming out from the first press machine (11) to the second press machine (12), wherein the intermediate feeding device (50) is provided with:
a first feeding line guide (52) and a second feeding line guide (53) each configured to support the coil strip W at a feeding line height H, the first feeding line guide (52) and the second feeding line guide (53) being arranged at two positions on an upstream side and a downstream side in a feeding direction of line, respectively;

a pair of upper and lower feeding rolls (51b) and (51a), the pair of upper and lower feeding rolls (51b) and (51a) being arranged between the first feeding line guide (52) and the second feeding line guide (53); and

a release mechanism (55) configured to release the feeding rolls (51b) and (51a) after completion of feeding the coil strip W so that the coil strip W is released before being positioned with respect to a die,

the intermediate feeding device (50) being characterized in that,

the pair of upper and lower feeding rolls (51b) and (51a) are configured to guide the coil strip W so that the coil strip W passes through a detour path shifted in a vertical direction with respect to the feeding line height H when feeding the coil strip W.
A tandem press line comprising:
a first press machine (11) configured to punch a coil strip W fed intermittently;

a second press machine (12) configured to further punch the coil strip W coming out from the first press machine (11), in synchronization with the first press machine (11); and

the intermediate feeding device (50) as recited in claim 1.
The tandem press line as recited in claim 2, wherein a crankshaft (17) of the first press machine (11) and a crankshaft (17) of the second press machine (12) are coupled to each other so as to be synchronously rotated.
The tandem press line as recited in claim 2 or 3, further comprising:
a press distance adjustment mechanism (13) configured to adjust a distance in a feeding direction of line between the first press machine (11) and the second press machine (12).
The tandem press line as recited in claim 3, further comprising:
a press distance adjustment mechanism (13) configured to adjust a distance in a feeding direction of line between the first press machine (11) and the second press machine (12),

wherein a crankshaft (17) of the first press machine (11) and a crankshaft (17) of the second press machine (12) are coupled to each other via a coupling (28) that allows movement in an axial direction.
The tandem press line as recited in claim 4 or 5,
wherein the press distance adjustment mechanism (13) is provided with:
a supporting device (21) configured to support either one or both of frames (16), (16) of the first press machine (11) and the second press machine (12) in a movable manner in a coil strip feeding direction;

a motor-driven movement drive mechanism (25) configured to connect both the frames (16) and (16);

a sensor (26) configured to detect a distance between a die installed on the first press machine (11) and a die installed on the second press machine (12); and

a control device C configured to perform control of driving the movement drive mechanism (25) so that a detected value of the sensor (26) coincides with a distance predetermined for each die.