JP6661473B2 - Transfer device gripping mechanism - Google Patents

Description

  The present invention relates to a gripping mechanism of a transfer device, and more particularly, to a gripping mechanism of a transfer device capable of detecting a chuck error of a work.

  In a transfer device provided in a multi-stage forging press machine in which a plurality of forging portions including a die and a punch are horizontally arranged in a horizontal direction, a pair of gripping claws grip a workpiece having a circular outer periphery, and a Conveyed to the forging section.

However, when gripping the workpiece with a pair of gripping claws, a problem such as dropping the workpiece, or gripping the workpiece in a state where the workpiece is tilted more obliquely than in a normal state, causing a so-called chuck error. In some cases.
Such a chuck error not only prevents the product from being formed into a predetermined shape, but also causes a trouble with the device such as interference of the work with the device. Need to detect.

As a specific means for detecting a chuck error of a work, Japanese Unexamined Patent Application Publication No. 2005-133873 discloses a detection circuit that applies a voltage to a pair of gripping claws and generates when there is no work between the gripping claws (in the case of a chuck error). It is disclosed that a chuck error is electrically detected based on a voltage fluctuation in the inside.
However, the technique disclosed in Patent Document 1 has a problem in that although the presence or absence of a work can be detected, a chuck error in a state where the work is tilted and gripped cannot be detected.

On the other hand, in Patent Document 2 below, when opening and closing three gripping claws (fingers) for gripping a work, a detecting plate is attached to an intermediate portion of an operating rod that moves in a vertical direction, and the moving amount of the detecting plate is swirled. It is disclosed that the current is detected by a current-type sensor, and that the waveform data obtained thereby is equivalent to the opening amount of the gripping claw, and that the abnormality is detected based on the waveform data.
However, the sensor described in Patent Literature 2 has a sensor mounted near a work to be forged. Since the work is usually processed at a high temperature of about 1200 ° C to 1000 ° C, if a sensor is provided near the work, it is possible to stably detect the opening of the gripping claw due to the influence of scale scattering and heat. difficult.
In addition, the operating rod to which the detection plate is attached has one end moving up and down and the other end moving circularly, so that the movement of the detection plate becomes complicated during the opening and closing movement of the gripping claws, and the range in which the position of the operation rod can be detected is narrow. It is limited to the range.

JP 2000-94070 A JP 2013-78791 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a gripping mechanism of a transfer device capable of stably detecting a workpiece chuck error at a gripping claw.

According to a first aspect of the present invention, there is provided a gripping mechanism of a transfer device provided in a multi-stage forging press in which a plurality of forging sections are arranged in a horizontal direction, and sequentially transporting a workpiece to a next forging section. A pair of gripping claws for gripping the workpiece , one gripping surface being formed as a flat surface and the other gripping surface being formed as a V-shaped groove, and the output shaft being moved back and forth in the axial direction when the gripping claw is opened and closed. Driving means for moving, a link mechanism for converting the forward / backward movement of the output shaft into an opening / closing movement in the left-right direction, and transmitting this to the pair of gripping claws; and an end of the output shaft opposite to the gripping claws. Is provided, position detecting means for detecting the position of the output shaft, based on an output from the position detecting means, abnormality detecting means for detecting a chuck error of the workpiece in the gripping claw ,
The link mechanism,
A drive link coupled to the output shaft and moving forward and backward with the output shaft;
A pair of tilting links extending in the left-right direction, a connecting pin rotatably connecting one end of the tilting links to each other, and rotatably connecting the pair of tilting links and the driving link; and a pair of tilting links. A slide pin provided at the other end of each of the links and moving along a guide groove extending in the left-right direction formed on the base,
The pair of gripping claws connected to the other ends of the tilting links are slid in the left-right direction to change the opening degree of the pair of gripping claws, and move the pair of gripping claws in the closing direction. At this time, the connecting pin of the opening / closing movement generating means is moved in a tilt direction inclined toward the gripping claw provided with the flat surface than in a vertical direction orthogonal to the horizontal direction, and the pair of gripping claws are gripped. Each of the gripping claws is moved so that the center position of the work in contact with the surface does not change .

  According to a second aspect of the present invention, the position detecting means has a detecting portion including a detecting rod and a sleeve externally fitted to the detecting rod, and one of the detecting rod and the sleeve is integrated with the output shaft. It is characterized by moving to.

As described above, the gripping mechanism of the present invention is provided at the end of the output shaft opposite to the gripping claw, and based on the position detection means for detecting the position of the output shaft and the output from the position detection means, Abnormality detecting means for detecting a chuck error of the workpiece with the gripping claw.
Generally, a workpiece to be forged is at a high temperature of about 1200 ° C. to 1000 ° C., and therefore, even if a sensor for detecting the opening of the gripping claw is provided in the vicinity of the workpiece or the gripping nail for gripping the workpiece, the scale is not affected. It is difficult to stably detect the degree of opening of the gripping claws due to the influence of scattering and heat.
On the other hand, according to the present invention, the position of the output shaft of the driving means that moves in conjunction with the opening and closing movement of the gripping claws is detected to detect a chuck error.
In particular, in the present invention, the position detection means is provided at the end of the output shaft opposite to the gripping claw, and according to the present invention, the opening of the gripping claw is stably opened without being affected by the scattering of scale or heat. , The position of the output shaft can be detected, and a chuck error can be detected based on this.

  Also, in the present invention, since the movement of the output shaft for detecting the position is a simple movement of moving forward and backward in the axial direction, the displacement of the output shaft using a generally used displacement sensor, such as a sleeve sensor or a differential transformer type sensor, The position of the output shaft can be detected over a wide range, so that a chuck error can be detected for a wide range of works from a work having a small outer diameter to a work having a large outer diameter.

According to the present invention, the position detecting means has a detecting portion including a detecting rod and a sleeve externally fitted to the detecting rod, and one of the detecting rod and the sleeve is moved integrally with the output shaft. (Claim 2).
According to the second aspect, even if the output shaft moves a long distance in the axial direction, the position of the output shaft can be easily detected by increasing the effective detection length of the detection unit in the axial direction. it can.
Further, in this case, since the detection unit is provided at the end of the output shaft on the side opposite to the gripping claws, there is no interference with other components constituting the gripping mechanism.

The present invention is particularly when the pair of gripping claws changing the opening, each of the gripping claws so that the center position does not change the work in contact with the pair of gripping surfaces that move position.
Conventionally, when the outer diameter of the work changes, a problem occurs in that the center position of the work when the work is gripped is shifted. Therefore, the gripping claws are exchanged. However, according to the present invention , a pair of gripping claws change the opening degree. At this time, if the respective gripping claws are moved so that the center position of the work in contact with the pair of gripping surfaces does not change, the gripping claws can be used as they are even when the outer diameter of the work changes. In addition, the replacement of the gripping claws and the adjustment work associated therewith can be made unnecessary, and the operation rate of the target facility can be improved.
In such a case, when a single gripping claw is used from a work having a small outer diameter to a work having a large outer diameter, the opening degree of the used gripping claw is widened from small to large. In addition, the moving distance of the output shaft also increases with this. However, the gripping mechanism of the present invention can detect the position of the output shaft over a long moving distance. It is possible to detect chuck errors of workpieces with different outer diameters.

  According to the present invention described above, it is possible to provide a gripping mechanism of a transfer device that can stably detect a workpiece chuck error at a gripping claw.

1 is a plan view of a multi-stage forging press provided with a gripping mechanism according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a schematic configuration of the transfer device of FIG. 1. FIG. 3 is a diagram illustrating a configuration of a grip unit of FIG. 2. FIG. 4 is a sectional view taken along line IV-IV of FIG. 3. FIG. 5 is a sectional view taken along line VV of FIG. 3. FIG. 4 is an enlarged view of a main body of the air cylinder of FIG. 3 and a peripheral portion thereof. It is a figure for explaining a grasp operation of a grasp device. It is a figure for explaining a problem by three points support.

Next, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a view showing a multi-stage forging press provided with a gripping mechanism of the transfer device of the present embodiment. In FIG. 1, reference numeral 10 denotes a multi-stage forging press (hereinafter, sometimes referred to as a forging press), which is a plurality of (here, three stages) for forging a work inside a box-shaped frame 12. Forged parts are arranged side by side at regular intervals in the horizontal direction.
The forged portion includes a die fixed to the frame 12 and a punch 16 arranged to face the die. Each of the punches 16 is mounted on the tip of a ram 18, and the material (work) is simultaneously formed in each forged portion by the forward movement of the ram 18.

In the forging press 10 of this example, a main motor 20 is provided as a power source of the ram 18. The main motor 20 is connected to a flywheel 24 via a belt 22, and the flywheel 24 is connected to a ram 18 via a crankshaft 26.
Specifically, a pinion gear 27 provided at an end of the flywheel shaft 25 opposite to the flywheel 24 and a large gear 28 provided at an end of the crankshaft 26 are connected in a meshing state.
Therefore, in this example, the flywheel 24 is rotated by the power of the main motor 20, and the ram 18 moves forward and backward by the power. That is, the punch 16 mounted on the tip of the ram 18 advances and retreats with respect to the die, and forging is performed.

In the forging press machine 10 configured as described above, a material (work W) supplied from the outside is formed into a predetermined shape by sequentially passing through the three-stage forging section. At this time, the transfer of the work W to each forging section is performed by the transfer device 30.
Then, the forged product is carried out of the machine by a carry-out device (not shown).

  As shown in FIG. 1, the forging press 10 of the present embodiment has an upper surface of the frame 12 opened at a portion where the forged portion is arranged, and a main body portion of the transfer device 30 is located at a position above the die in this open space. Is arranged.

FIG. 2 is a diagram showing a schematic configuration of the transfer device 30.
In the figure, reference numeral 36 denotes a gripping unit provided with a pair of gripping claws 50 and 52 for gripping a work, which are mounted at equal intervals on a vertical mounting surface of the transport plate 31.
A solenoid valve 39 supplies high-pressure air to the air cylinder 46 when opening and closing the grip claws 50 and 52 of the grip unit 36.
A servo motor 33 is connected to the transfer plate 31, and the transfer plate 31 and the grip unit 36 can be moved in a horizontal direction, which is a direction in which the forged portions are arranged.
In some cases, in addition to the servomotor 33 for moving in the horizontal direction, a servomotor for moving in the vertical direction is attached to the transport plate 31 so that the transport plate 31 can be moved in the vertical direction. It is also possible.

Reference numeral 38 denotes a control unit that controls the work transfer operation in the transfer device 30. The horizontal movement of the transport plate 31 and the opening and closing operations of the grip claws 50 and 52 in the grip unit 36 are controlled by the control unit 38 based on an encoder signal from the crankshaft 26 that moves the ram 18 back and forth.
Further, as described later, the control unit 38 determines whether or not a workpiece chuck error has occurred in the gripping claws 50 and 52 based on an output from the sleeve sensor 98 attached to each gripping unit 36. You can do it.

3 is a diagram showing the configuration of the grip unit 36, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is a sectional view taken along line VV of FIG.
In FIG. 3, reference numeral 42 denotes a housing constituting a base of the gripping unit 36, which comprises a case body 44 and a lid 45. FIG. 3 shows a state where the lid 45 is removed.

In FIG. 3, reference numeral 46 denotes an air cylinder as driving means, and 48 denotes a link mechanism housed inside the housing 42.
In this example, the vertical movement by the air cylinder 46 is converted into the horizontal movement by the link mechanism 48 and transmitted to the gripping claws 50 and 52 connected to the output end of the link mechanism 48.

  The air cylinder 46 has a main body 54 fixed to the upper end surface of the housing 42, and an output shaft 55 extends downward from the main body 54 into the housing 42 in the drawing. The output shaft 55 advances and retreats in the vertical axial direction in the figure by air introduced into the main body 54.

One end of a first drive link 56 constituting a part of the link mechanism 48 is rotatably connected to a tip end of the output shaft 55 via a connection pin 57. A second drive link 58 is rotatably connected to the other end of the first drive link 56 via a connection pin 59.
As shown in FIG. 4, in the present embodiment, the first drive link 56 and the second drive link 58 are each divided into two parts at right and left positions in the figure, which are symmetrical with respect to the center line of the output shaft 55. Is provided.
When the output shaft 55 of the air cylinder 46 moves up and down, the first drive link 56 and the second drive link 58 also move up and down.
In this example, the first drive link 56 and the second drive link 58 form a drive link that moves forward and backward together with the output shaft.
In this example, when the second drive link 58 moves up and down in FIG. 3, the output shaft 55 moves so that the axis of the second drive link 58 can move in the left-right direction with respect to the center axis of the output shaft 55. A first drive link 56 is provided between the output shaft 55 and the second drive link 58 for the purpose of absorbing a lateral shift occurring between the shaft 55 and the second drive link 58.

To one end of the second drive link 58, a first opening / closing movement generating means 60 for converting the forward / backward movement of the second drive link 58 into a left / right opening / closing movement is rotatably connected by a connecting pin 59.
The first opening / closing motion generating means 60 includes a pair of tilting links 62 and 64 extending separately in the left-right direction, a connecting pin 59 that rotatably connects one end of the tilting links 62 and 64, and each of the tilting links 62 and 64. And slide pins 66 and 68 provided at the ends.
As shown in FIG. 5, in the present embodiment, these tilting links 62 and 64 are provided at two positions symmetrical with respect to the center line of the output shaft 55.
Each of the slide pins 66 and 68 is formed with a flange 69 having a rectangular shape in a plan view at both ends thereof. These flanges 69 are formed on guide grooves 70 formed on the case body 44 and the lid 45 and extending in the left-right direction. It is slidably engaged.
A flange 72 having a rectangular shape in a plan view is also formed at one end (on the side of the lid 45) of the connecting pin 59, and the flange 72 can slide in a guide groove 73 formed in the lid 45. Is engaged.
In the first opening / closing motion generating means 60, when the connecting pin 59 is pulled up in the upward direction orthogonal to the left / right direction, the slide pins 66 and 68 move in the left / right closing direction. On the other hand, when the connecting pin 59 is pushed down in the opposite direction, the slide pins 66 and 68 move in the left and right opening directions, respectively.

The other end of the second drive link 58 is rotatably connected by a connection pin 78 to a second opening / closing movement generating means 76 for converting the forward / backward movement of the second drive link 58 into a left / right opening / closing movement.
The second opening / closing motion generating means 76 includes a pair of tilting links 80 and 82 extending separately in the left-right direction, a connecting pin 78 for rotatably connecting one end side of each of the tilting links 80 and 82, and another of the tilting links 80 and 82. And slide pins 84 and 86 provided at the ends.
Each of the slide pins 84 and 86 has a flange 87 having a quadrangular shape in a plan view formed at both ends thereof. The flange 87 slides into a guide groove 88 formed in the case body 44 and the lid 45 and extending in the left-right direction. It is movably engaged.
A flange 79 having a rectangular shape in a plan view is also formed at one end (on the side of the lid 45) of the connecting pin 78, and the flange 79 slides into a guide groove 90 formed in the lid 45. Engage as possible.
Similarly to the first opening / closing motion generating means 60, when the connecting pin 78 is pulled up in a direction perpendicular to the left / right direction, the slide pins 84 and 86 move in the closing direction in the left / right direction. Move position. On the other hand, when the connecting pin 78 is pressed down in the opposite direction, the slide pins 84 and 86 move in the left and right opening directions, respectively.

The first opening / closing motion generating means 60 and the second opening / closing motion generating means 76 provided in the vertical direction along the second drive link 58 are configured such that the respective left tilting links 62 and 80 in FIG. The slide pins 66 and 84 on the left side in each figure are set to be at the same position in the left-right direction.
Similarly, the right tilt links 64 and 82 in FIG. 3 have the same link length, and the right slide pins 68 and 86 in the respective drawings are set to be at the same position in the left-right direction.

Reference numerals 92 and 94 denote a pair of output links extending vertically.
The output link 92 on the left side in FIG. 3 is connected to the slide pin 66 of the first opening / closing movement generating means 60 and the slide pin 84 of the second opening / closing movement generating means 76, respectively, and the output link 94 on the right side in FIG. It is connected to the slide pin 68 of the first opening / closing movement generating means 60 and the slide pin 86 of the second opening / closing movement generating means 76, respectively. The position is moved in the left and right direction in accordance with the positions of the slide pins while maintaining the parallel state.
In this example, like the output link 94 shown in FIG. 5, the pair of output links 92 and 94 are provided at two positions symmetrically with respect to the center line of the output shaft 55. I have.

The gripping claws 50 and 52 are connected to the lower ends of the pair of output links 92 and 94, respectively.
As shown in FIG. 3, the pair of gripping claws 50 and 52 are opposed to each other in the left-right direction with the gripping surface for gripping the workpiece facing inward. In this example, the gripping surface 51 of the gripping claw 50 on the left side in the figure is formed as a flat surface, and the gripping surface 53 of the gripping claw 52 on the right side in the figure is formed as a V-shaped groove.
The slope formed on the grip surface 53 is inclined in the vertical direction by an angle θ with respect to the imaginary line in the horizontal direction, and in this example, θ = 60 °.
In this example, a work having a circular outer periphery is supported at three points by the pair of gripping claws 50 and 52.

However, in the case of such three-point support, there occurs a problem that the center position of the work is shifted when the diameter of the work to be gripped is changed (hereinafter, may be referred to as misalignment).
The misalignment in the three-point support is due to the following reasons.
For example for FIG. 8 (A) the center position O ₁ from the state a large gripping the workpiece W ₁ of such diameter as indicated by the grips small the workpiece W ₂ of the same in diameter, on both sides of the gripping claws in the same amount closing direction, respectively when the movement is, only the gripping claws 110 having a first flat surface, as shown in FIG. 8 (B) is in contact with the workpiece W _2, between the gripping claws 112 with a V-shaped groove at this time the workpiece W ₂ Still has a gap left. When the gripping claws 110, 112 of the further sides from this state is moved in the closing direction the workpiece W ₂ is made to move in the right side in the drawing by the gripping claws 110 having a flat surface, eventually workpiece W _2, as shown in FIG. 8 ( Figure 8 (a) and as indicated by C) work center is gripped by both gripping claws 110 and 112 at different locations _{O 2.}

As can be seen from this, when the diameter of the work changes, the misalignment occurs because the contact position between the work and the gripping surface is asymmetrical in the left and right direction, and the amount of movement required until the work abuts on the left and right. Unlike the gripping claws, gripping without changing the center position of the work is due to the insufficient amount of movement of the gripping claws 112 having the V-shaped groove. The gripping claws need to be replaced, which causes the equipment to stop and causes a reduction in the equipment operation rate.
Therefore, in the present embodiment, as described below, when the opening degree of the pair of gripping claws 50 and 52 is changed, the center position of the work in contact with the gripping surfaces 51 and 53 of the pair of gripping claws 50 and 52 for gripping the work is changed. The gripping claw 52 having the V-shaped groove is moved more than the gripping claw 50 having the flat surface so as not to change.

As shown in FIGS. 3B and 4, the cover 45 has a guide groove 73 for guiding the movement of the connecting pin 59 of the first opening / closing movement generating means 60 and a connecting pin of the second opening / closing movement generating means 76. Guide grooves 90 for guiding the movement of 78 are respectively formed.
As shown in FIG. 3B, the guide groove 73 is inclined at an angle α to the side of the gripping claw 50 having a flat surface (left side in the figure) with respect to an imaginary line in the vertical direction perpendicular to the horizontal direction. ing. The flange 72 of the connecting pin 59 is slidably engaged with the guide groove 73.

On the other hand, similarly to the guide groove 73, the guide groove 90 provided below the guide groove 73 is also provided at an angle α with respect to the vertical imaginary line. Is engaged so as to be slidable.
In this example, when the pair of gripping claws 50, 52 are moved in the closing direction, the connecting pins 59, 78 of the opening / closing motion generating means 60, 76 are inclined more toward the gripping claw 50 having a flat surface than in the vertical direction. By moving, the gripping claw 52 provided with the V-shaped groove is moved more than the gripping claw 50 provided with the flat surface, thereby effectively preventing misalignment of the work when the outer diameter of the work W changes.
The guide grooves 73 and 90 are provided for moving the connecting pins 59 and 78 in the above-described inclined direction.
The angle α for preventing misalignment varies depending on the length of the tilting link constituting the opening / closing motion generating means and the angle of the slope of the V-shaped groove in the gripping claw, so that an appropriate angle is appropriately used as necessary. be able to.

Next, FIG. 6 is a diagram showing the main body portion 54 of the air cylinder 46 and its peripheral portion.
As shown in FIG. 6A, a piston 95 that slides inside the main body 54 of the air cylinder 46 is attached to the base end of the output shaft 55 of the air cylinder 46.
Working chambers 96 and 97 defined by the piston 95 and a container of the main body 54 are formed on both sides of the piston 95 in the vertical direction.
In this example, air at a predetermined pressure is supplied to one working chamber, and air is exhausted from the other working chamber to move the piston 95 and the output shaft 55 up and down.

Further, a sleeve sensor 98 is provided at an end of the output shaft 55 opposite to the gripping claw, as a position detecting means for detecting the position of the output shaft 55.
The sleeve sensor 98 of the present embodiment includes a sensor main body 99, a detection rod 100, and a metal cylindrical sleeve 101 that is fitted around the detection rod 100.
A thin coil for generating a high-frequency magnetic field is housed inside the detection rod 100, and a gap between the detection rod 100 and the sleeve 101 generated when the sleeve 101 externally fitted to the detection rod 100 moves relatively in the axial direction. The voltage value output from the sensor body 99 changes based on the strength of the electromagnetic coupling acting on the sensor body 99.

FIG. 6B is an enlarged view of the detection rod 100 and the sleeve 101.
In the figure, reference numeral 110 denotes a bracket attached to the main body 54 of the air cylinder 46, which supports the detection rod 100 of the sleeve sensor 98 in a fixed state.
On the other hand, a connecting member 102 is attached to the end of the output shaft 55 and extends upward in the axial direction. A guide hole 104 that opens upward is formed in the shaft portion, and the sleeve 101 is attached to the inner peripheral surface thereof. ing.

Therefore, in this example, when the output shaft 55 moves linearly in the axial direction to open and close the gripping claws 50, 52, the sleeve 101 attached to the output shaft 55 also moves linearly in the axial direction. . Therefore, the relative position of the sleeve 101 with respect to the detection rod 100 changes, and the sleeve sensor 98 outputs a voltage value corresponding to the position of the output shaft 55.
Since this output value also corresponds to the degree of opening of the gripping claws 50, 52, the control unit 38 can detect the degree of opening of the gripping claws 50, 52 based on the output from the sleeve sensor 98.

Next, a gripping operation in the gripping unit 36 of the present example will be described.
The air cylinder 46 is driven in a state where the gripping claws 50 and 52 are located on both left and right sides of the work W (the state shown in FIG. 3), and the first drive link 56 and the second drive link 58 are moved upward together with the output shaft 55. When pulled up, the connecting pin 59 and the connecting pin 78 connected to the second drive link 58 are guided by the guide grooves 73 and 90, respectively, as shown in FIG. 7, and upward (in detail, diagonally toward the upper left) in the figure. Moving.
Accordingly, the slide pins 66, 68 of the first opening / closing movement generating means 60 and the slide pins 84, 86 of the second opening / closing movement generating means 76 move in the closing direction toward the center, and are connected to these slide pins. The output links 92, 94 and the gripping claws 50, 52 attached to the ends of the output links 92, 94 also move in the closing direction toward the center.

In this example, the trajectories of the connecting pin 59 of the first opening / closing movement generating means 60 and the connecting pin 78 of the second opening / closing movement generating means 76 are defined by the guide grooves 73 and 90, respectively, so as to be inclined by the angle α. When the gripping claws 50, 52 move in the closing direction, the first opening / closing motion generating means 60 and the second opening / closing motion generating means 76 are provided with flat gripping claws with the inclination of the guide grooves 73, 90. To move to the side of 50 (left side in the figure), the gripping claw 52 having the V-shaped groove moves more than the moving amount of the gripping claw 50 having the flat surface.
As described above, in this example, when the pair of gripping claws change the opening degree, the gripping claws 52 having the V-shaped groove are moved more than the moving amount of the gripping claws 50 having the flat surface, so that V It is possible to prevent the workpiece from being misaligned due to the insufficient amount of movement of the gripping claw 52 having the groove, and to keep the workpiece center position constant regardless of the size of the workpiece W to be gripped. The workpiece W can be gripped in the state.

If a chuck error occurs when gripping the workpiece, an output corresponding to the position of the output shaft 55 is output from the sleeve sensor 98 to the controller 38 in this example. Thus, a chuck error can be detected.
For example, when gripping a small workpiece W ₂ of the outer diameter at the gripping claws 50, 52, set in advance an upper limit value and the lower limit value for the output value F ₂ from the sleeve sensor 98 when gripping the workpiece W ₂ normally Keep it.
If the output value from the sleeve sensor 98 exceeds the upper limit value despite the closing operation of the gripping claws 50, 52, the opening of the gripping claws 50, 52 is larger than the normal state, that is, it is determined that the work W ₂ are gripped in a state obliquely inclined, the control unit 38 stops the operation of the transfer device 30.
On the other hand, when the output value from the sleeve sensor 98 falls below the lower limit, normal state opening degree is small state of gripping claws 50 and 52 than, i.e. the workpiece W ₂ is not (not held) state It is determined that there is, and also in this case, the operation of the transfer device 30 is stopped.

Also, when gripping a large workpiece W ₁ of the outer diameter, setting the upper and lower limits as well the output value F ₁ from the sleeve sensor 98 when gripping the workpiece W ₁ successfully.
By setting an upper limit and a lower limit for detecting a chuck error with respect to the output value from the sleeve sensor 98 when the workpiece is normally gripped for each outer diameter of the workpiece to be gripped, Based on the output from the sensor 98, a chuck error can be detected for works of various sizes.

  As described above, in the present embodiment, the sleeve sensor 98 is provided at the end of the output shaft 55 opposite to the gripping claws, so that the gripping claws 50, The position of the output shaft 55 corresponding to the opening of the shaft 52 can be detected, and a chuck error can be detected based on the detected position.

  Further, in the present embodiment, since the movement of the output shaft 55 for detecting the position is a simple movement of moving forward and backward in the axial direction, the position of the output shaft 55 can be determined over a wide range in the axial direction using the sleeve sensor 98. Thus, a chuck error can be detected for a wide range of work from a work having a small outer diameter to a work having a large outer diameter.

In the present embodiment, the sleeve sensor 98 has a detection unit including a detection rod 100 and a sleeve 101 that is fitted on the detection rod 100, and the sleeve 101 is configured to move integrally with the output shaft 55. Therefore, even if the output shaft 55 moves a long distance in the axial direction, it can be easily coped with by increasing the effective detection length of the detection unit (the detection rod 100 and the sleeve 101) in the axial direction. it can.
Further, in this case, since the detection unit is provided at the end of the output shaft 55 opposite to the grip claws 50 and 52, there is no interference with other components constituting the grip mechanism.

In the present embodiment, when the pair of gripping claws 50 and 52 change the opening, the respective gripping claws 50 and 52 move so that the center position of the work in contact with the pair of gripping surfaces 51 and 53 does not change. Even when the outer diameter of the work changes, the gripping claws 50 and 52 can be used as they are. For this reason, in this example, the replacement of the gripping claws and the adjustment work associated therewith can be made unnecessary, and the operating rate of the forging press 10 can be improved.
In this case, when the work is performed from a work having a small outer diameter to a work having a large outer diameter, the opening degree of the gripping claws 50 and 52 used is also widened from small to large. In addition, the moving distance of the output shaft 55 also increases with this. However, in the present embodiment, the position of the output shaft 55 can be detected over a long moving distance. It is possible to satisfactorily detect chuck errors of workpieces having different outer diameters.

The embodiment of the present invention has been described in detail above, but this is merely an example. In the above embodiment, the gripping claws that support the work at three points that are asymmetrical to the left and right are used. However, depending on the case, the gripping claws that support the left and right gripping surfaces with four V-shaped grooves may be used. It is possible.
In this case, even if the diameter of the workpiece to be gripped changes, the center deviation of the workpiece can be prevented only by moving the left and right gripping claws by the same amount.
Further, the present invention is not limited to the above-mentioned sleeve sensor as a sensor as a position detecting means for detecting the position of the output shaft, and other displacement sensors such as a differential transformer type sensor can be used. The present invention can be implemented with various modifications without departing from the spirit of the invention.

Reference Signs List 10 forging press machine 30 transfer device 36 gripping unit 38 control unit (abnormality detection means)
46 air cylinder (drive means)
48 Link mechanism 50, 52 Gripping claw 51, 53 Gripping surface 55 Output shaft 98 Sleeve sensor (position detecting means)
100 Detection rod 101 Sleeve

Claims (2)

A gripping mechanism of a transfer device that is provided in a multi-stage forging press in which a plurality of forging sections are arranged in a horizontal direction and sequentially conveys a workpiece to a next forging section.
A pair of gripping claws for gripping the work , wherein one gripping surface is a flat surface and the other gripping surface is a V-shaped groove ,
Driving means for moving the output shaft in the axial direction at the time of opening and closing movement of the gripping claws,
A link mechanism that converts the forward / backward movement of the output shaft into a left / right opening / closing movement, and transmits this to the pair of gripping claws;
Position detecting means provided at an end of the output shaft opposite to the gripping claw, and detecting a position of the output shaft,
Abnormality detecting means for detecting a chuck error of the work at the gripping claw based on an output from the position detecting means ,
The link mechanism,
A drive link coupled to the output shaft and moving forward and backward with the output shaft;
A pair of tilting links extending in the left-right direction, a connecting pin rotatably connecting one end of the tilting links to each other, and rotatably connecting the pair of tilting links and the driving link; and a pair of tilting links. A slide pin provided at the other end of each of the links and moving along a guide groove extending in the left-right direction formed on the base,
The pair of gripping claws connected to the other ends of the tilting links are slid in the left-right direction to change the opening degree of the pair of gripping claws, and move the pair of gripping claws in the closing direction. At this time, the connecting pin of the opening / closing movement generating means is moved in a tilt direction inclined toward the gripping claw provided with the flat surface than in a vertical direction orthogonal to the horizontal direction, and the pair of gripping claws are gripped. A gripping mechanism for a transfer device, wherein each gripping claw is moved so that the center position of the work in contact with a surface does not change .   2. The device according to claim 1, wherein the position detecting means has a detecting portion including a detecting rod and a sleeve externally fitted to the detecting rod, and one of the detecting rod and the sleeve moves integrally with the output shaft. A transfer device gripping mechanism.

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