JPH0677906B2 - Key striking device for forging machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used to perform a work of driving a key for fixing the upper and lower molds or a saw block of a forging machine and pulling out the key. The present invention relates to a key striking device for a forging machine.

[Prior Art] A forging machine 1 such as an air-stamp hammer shown in FIG.
An upper mold 3 attached to the lower end of the ram 2 to be raised and lowered and a lower mold 5 attached to the saw block 4 are provided, and a metal material is forged between the upper and lower molds 3, 5. These molds
3,5 and saw block 4 have a key 6 on one side, respectively.
It has been fixed by typing. Of course, the key 6 is driven from the front side or the rear side of the forging machine 1, and the key 6 may be longer or shorter than the thickness of the dies 3, 5 or the saw block 4 in the front-rear direction. In FIG. 8, 7 is a bolt for connecting the left and right frames 1b to the base 1a of the forging machine 1, and 8 is a hole opened at both front and rear end surfaces of the saw block 4.

Then, when the key 6 for fixing the molds 3, 5 and the saw block 4 is driven in and out, the thrust rod is usually hung horizontally on an appropriate support member on the ceiling side, and the rod is bell-struck. It is performed by operating and hitting the key at its tip through a jig.

However, in the case of such manual work, the workability is poor and skill is required, and it is difficult to hit the key accurately. In addition, when the impact is inadequate, the impact rod is likely to freely move and hit the operator due to the energy of the impact, so the work risk is very high.

Therefore, a key striking device that does not require manual work is conventionally known. This device is used by being fixed to a fork of a forklift truck, and a rod of a piston included in an air cylinder mechanism is projected from the cylinder and a jig is attached to the tip thereof. Therefore, by retracting the piston and rapidly advancing the piston with air pressure, the piston and the jig are used as hammers to strike the key, whereby the key can be driven in and removed.

[Problems to be Solved by the Invention] However, in such a conventional key striking device, it is undeniable that the forklift truck may move to some extent due to the reaction force at the time of striking, and at the same time, the key is driven by striking. When performing the next impact, the forklift truck needs to be advanced to the forging machine side, and each time, the jig core must be aligned with the key core. In this case, since there is no means for restricting the mutual position of the key and the tip of the piston rod, it is difficult to aim the piston rod with respect to the core of the key. Therefore, in the conventional device, there is a problem that the work required for hitting is great and the workability is poor. Moreover,
Since a forklift truck is used, an operator of the key striking device is required together with its driver, which requires a lot of manpower. Moreover, since a forklift truck is used, a space for arranging the truck is required around the forging machine, and there is a problem that the device cannot be applied if such a space cannot be secured.

An object of the present invention is to obtain a key striking device for a forging machine, which can strike a key with high workability without requiring a lot of manpower and a lot of space, and which can prevent damage due to idling. Especially.

[Means for Solving the Problem] In order to achieve the above object, in the key striking device for a forging machine of the present invention, a piston hammer is provided in a cylinder that is arranged with its axes aligned in the longitudinal direction of the forging machine. An air tank is connected to the cylinder through a first switching valve that movably accommodates the hammer and reciprocates the hammer in the front-rear direction, and the cylinder-shaped rod holder connected to the front end of the cylinder has a rear portion at the rear. It is formed to have a large diameter portion, a small diameter portion on the front side of this large diameter portion is provided so as to project from the front end of the rod holder, and it contacts the end surface of the key of the forging machine via a jig and the piston A hammer movably supports a striking rod that collides from the rear, a stopper portion that restricts the retracted position of the striking rod is provided in the rod holder, and the rod holder has the striking rod. A pressure receiving ring that forms a closed air reservoir through which the small diameter portion of the lid penetrates is formed in front of the large diameter portion of the striking rod.
A mooring cylinder mechanism having a piston rod projecting rearward of the cylinder is connected to the cylinder and is housed so as to be movable in the front-rear direction so as to face the large-diameter portion, and the mechanism and the air tank are connected to each other. The piston rod communicates with each other through a second switching valve that reciprocates in the front-rear direction, a rope connecting member is connected to the tip end portion of the piston rod, and the tip end portion of the forging machine is hooked at the time of striking the key. Each of a plurality of mooring lines connected to the above are connected to the above-mentioned line connecting member.

[Operation] In this key striking device, the jig mounted on the tip of the striking rod whose retracted position with respect to the rod holder is regulated by the stopper is brought into contact with the end face of the key of the forging machine, It is placed horizontally in front of or behind. In this arrangement state, the plurality of tethers are stretched and held by hooking the tips of the tethers to the hooks of the forging machine. This tensioning is performed by operating the second switching valve to guide the fluid pressure from the fluid pressure source to the anchoring cylinder mechanism. As a result, the piston rod of the cylinder mechanism moves in the direction away from the forging machine, so that each mooring line is stretched and held. Then, the entire key striking device receives a force on the forging machine side, and the contact state between the jig and the key is maintained.

In the above arrangement state, the pressure of the air tank is introduced into the cylinder via the first switching valve, and the piston hammer in the cylinder is moved toward the forging machine. Then,
The hammer collides with the rear end of the striking rod and applies a striking force to the key through the rod and the jig at its tip. In this case, since the cylinder and the rod holder relatively position the piston hammer and the striking rod, the piston hammer can collide with the striking rod without aiming differently.

Since the key striking device is moved to the forging machine side by the force continuously applied to the entire key striking device by the anchoring cylinder mechanism, the entire amount of the key striking device is moved to the forging machine side, so that the jig and the key are moved. The contact state with is still maintained.

Next, the piston hammer in the cylinder is returned so as to be separated from the striking rod by the pressure of the fluid pressure source guided into the cylinder through the switching operation of the first switching valve, and then the first switching valve is switched again. Then hit the key. The key can be driven in or out by repeating the above-mentioned impacts a required number of times.

When the key is removed when the key is removed, the resistance force (key holding force) that prevents the striking rod from moving forward disappears, so the striking energy of the striking rod acts on the front portion of the rod holder. It is in a hit state. However, in this case, since the large diameter portion of the striking rod collides with the pressure receiving ring, the air enclosed in the air reservoir is compressed by the forward movement of this ring. The resulting air cushion can absorb the impact energy.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

Reference numeral 11 in FIG. 6 is a lifter capable of moving up and down the pedestal 12 by a petal operation or the like, which has wheels 13 and is movable. A key striking device 14 is detachably connected and supported on the upper surface of the gantry 12.

The striking device 14 will be described below. 15 in Figures 1 to 3
Is a base having a long shape along the front-rear direction of the forging machine (reference numeral 1 in FIG. 8), and a cylinder 16 is attached to the upper surface thereof. The cylinder 16 has a cylinder end member 17 attached to its rear end (the end farther from the forging machine 1). A first port 18 is formed in the member 17, and a cushioning material 19 is attached to the inner surface of the end plate 17a of the end member 17. 20 in FIG. 1 is a lock nut,
In FIG. 2, 15a is a suspension ring.

Front end of cylinder 16 (end closer to forging machine 1)
A cylinder-shaped rod holder 21 is connected to. The holder 21 is provided with a second port 22 communicating with the inside of the cylinder 16. A cylindrical plain bearing is provided at the center of the holder end member 24 that the rod holder 21 has at its front end.
25 is installed.

A striking rod 26 is housed in the rod holder 21 in front of the second port 22. The rear end portion of the rod 26 has a larger diameter than the other portions, and the large diameter portion 26a slides along the inner peripheral surface 21a of the rod holder 21. The small-diameter portion 26b of the striking rod 26, which is formed on the front side of the large-diameter portion 26a, slidably penetrates the slide bearing 25,
It projects from the front end of the rod holder 21. 21 in Fig. 1
b is engaged with the rear end of the striking rod 26, and this rod 26
Is a stopper portion formed of a stepped portion provided in the rod holder 21 in order to regulate the retracted position (the position that is moved most rearward with respect to the rod holder 21).

A pressure receiving ring 76 is housed in the rod holder 21 to form a closed air reservoir 75. The air reservoir 75 and the pressure receiving ring 76 are provided on the large diameter portion 26a of the striking rod 26.
The small-diameter portion 26b is provided at a position further forward than the small-diameter portion 26b. The pressure receiving ring 76 is movable in the front-rear direction and is provided so as to face the large diameter portion 26a. The rod holder 21 is provided with an exhaust hole 23 which is located in front of the second port 22 and behind the air reservoir 75 and communicates with the inside of the rod holder 21.

A jig 27 is detachably fitted and attached to the projecting front end portion of the striking rod 26, and the jig 27 is brought into contact with the tip of the key 6 of the forging machine 1. When the end of the key 6 is projected more than the front surface or the rear surface of the molds 3 and 5, for example, a jig having a groove for fitting the end of the key 6 at the tip is used. Also, the end of the key 6 is, for example, the mold 3,5.
When the key 6 is more retracted than the front or rear surface, a jig having a protrusion at its tip that contacts the retracted end of the key 6 is used.

A piston hammer 28 is movably accommodated in the cylinder 16. The hammer 28 collides with the rear end of the striking rod 26 when moving forward.

A first switching valve 30 is attached to the rear end of the cylinder 16, and the inside of the cylinder 16 has an air tank 31 through the valve 30.
Is in communication with. The air tank 31 covers most of the cylinder 16 and is mounted on a cover 32 provided on the base 15. In FIG. 1, reference numeral 33 is an opening / closing valve, 34 is a pressure regulating valve, and 35 is a pressure gauge. Air is appropriately replenished into the air tank 31 via these.

As shown in FIG. 1, the first switching valve 30 includes a valve casing 39 having a neutral valve chamber 36, each of which has an annular shape, and a first valve chamber 37 and a second chamber valve 38 formed on both sides of the neutral valve chamber 36. Inside, through holes 40-43
The sleeve 44 having the above is attached, and the valve element 45 is slidably provided inside the sleeve 44. The through hole 40 communicates with the neutral valve chamber 36, the through hole 41 communicates with the first valve chamber 37, and the through hole
42 and 43 are communicated with the second valve chamber 38. Communication hole 42 is through hole 43
Is formed smaller than.

The valve body 45 is reciprocally moved through the operation handle 46,
When it is moved forward, the neutral valve chamber 36
The first valve chamber 37 is communicated with the first valve chamber 37 via 0, 41, and when it is moved rearward, the neutral valve chamber 36 passes through 40, 42, 43.
It is adapted to communicate with the second valve chamber 38 via. The neutral valve chamber 36 is connected to the air tank 31 via a pipe 47, and the first valve chamber 37 is the first valve chamber 37 of the cylinder 16.
It is connected to port 18.

A quick exhaust valve 51 is attached to the outer surface of the front portion of the cylinder 16. As shown in FIG. 4, the exhaust valve 51 includes a valve seat body 52, a fixed cylinder body 53 fixed to the valve seat body 52, an operating cylinder 54 fixed to the cylinder body 53, and a cylinder.
The piston 55 accommodated in the cylinder 54 and the piston 55 is movably provided through the working cylinder 54 and is provided at one end.
Valve body 56 attached with a coil spring for urging the valve body 56
57 and a movable cylindrical body fitted outside the fixed cylindrical body 53
It is formed from 58 and.

The passage 52a of the valve seat body 52 is communicated with the second port 22 of the piston 16 and is opened and closed by the valve body 56. The coil spring 57 presses the valve body 56 against the valve seat body 52 in order to stabilize the closed state of the valve body 56. A port 59 communicating with the passage 52a is formed in the valve seat body 52, and the port 59 communicates with the second valve chamber 38 of the first switching valve 30.

The working cylinder 54 is provided with ports 54a and 54b at the upper end and the lower end in FIG. 4, respectively. The port 54a communicates with the second valve chamber 38 of the first switching valve 30. The port 54b communicates with the first valve chamber 37 of the first switching valve 30.

The fixed cylindrical body 53 and the movable cylindrical body 58 are provided with exhaust holes 53a and 58a, respectively, at predetermined intervals, and their communication areas are adjusted by the rotating operation of the movable cylindrical body 58. As shown in FIG. 5, the adjustment position is fixed by a screw 60 screwed into the fixed cylinder 53 through the arc-shaped adjustment hole 58b of the movable cylinder 58.
This is done by tightening (see Fig. 4).

An anchoring cylinder mechanism 61 is connected to the outer surface of the cylinder 16. This cylinder mechanism 61 is shown in FIGS.
As shown in the figure, it is formed of a mooring cylinder 62, a piston 63 housed in this cylinder 62, and a piston rod 64 connected to one end of this piston 63. The piston rod 64 projects rearward of the anchoring cylinder 62, in other words, in a direction away from the forging machine 1.

As shown in FIG. 7, the ports 62a and 62b of the connecting cylinder 62 at the front and rear ends thereof are connected to the air tank 31 via the second switching valve 65 shown in FIGS. 6 and 7. ing. In the second switching valve 65, when the air in the air tank 31 is guided to the front port 62a, the rear port 62b is opened to the atmosphere, and the air in the air tank 31 is guided to the rear port 62b. At times, a switching valve having a structure that opens the front port 62a to the atmosphere is used. The operation handle 66 of the switching valve 65 is shown in FIG.

As shown in FIGS. 1 and 2, a cable connecting member 67 is connected to the tip of the piston rod 64 of the cylinder mechanism 61. The member 67 is formed, for example, by connecting a tubular body 70 to the central portion of a plate 69 through which an elongated window 68 (see FIG. 6) provided in the cover 32 in the front-rear direction is inserted.
The tubular body 70 is fitted around the outer circumference of the cylinder 16 so as to be movable in the front-rear direction by using this as a guide. One end of each tether 71 is connected to the left and right ends of the plate 69 protruding from the window 68. For example, a chain is used for the mooring line 71. The tips of these tethers 71 are the above forging machine 1.
The bolt 7 is used as a hook portion, or a round bar is inserted into the hole 8 of the forging machine 1 and is used as a hook portion to be connected to the forging machine 1.

Next, the operation of the key striking device 14 having the above configuration will be described.

First, the key striking device 14 is horizontally arranged on the front side or the rear side of the forging machine 1, the jig 27 is attached to the front end portion of the striking rod 26, and then the lifter 11 is operated so that the center of the jig 27 is Adjust the height of the lifter 11 so that it fits the core of the key 6 of the forging machine 1. If the lifter 11 cannot be used, remove the key striking device 14 from the lifter 11
The height of the key striking device 14 may be adjusted by suspending the key striking device 14 on a chain block of a hoist or the like by using suspension rings 15a provided at both front and rear ends of 14. After this adjustment, a pair of left and right tethers
The tip portion of 71 is hooked on the hook portion of the forging machine 1, and this is stretched to bring the jig 27 into contact with the end surface of the key 6.

The tensioning of each tether 71 is performed by the operation handle 66 of the second switching valve 65.
By rotating the lever in the forward direction (see FIG. 6) (this state is held until the next operation of the operation handle 66 even if the operation handle 66 is released). This is realized by guiding the air in the air tank 31 to the port 62a of the cylinder 62 of the mechanism 61. That is, the piston rod 64 of the cylinder mechanism 61 is thereby changed to the forging machine 1.
Since it moves backward away from, each mooring line 71 is stretched by the movement of the line connecting member 67 accompanying it. Therefore, the cylinder mechanism 61 presses the entire key striking device 14 toward the forging machine 1 to maintain the contact state between the jig 27 and the key 6. Since the cable connecting member 67 has the tubular body 70 and the lower portion of the tubular body 70 supports the cylinder 16 from below, the entire key striking device 14 contacts the key 6 by the support. It is possible to stabilize the device 14 by preventing it from rotating around the contact.

After setting the key striking device 14 in the forging machine 1 as described above, the operation handle 46 of the first switching valve 30 is moved from the neutral position to the striking (see FIG. 6) position. Then,
The valve body 45 is moved rearward (leftward in FIG. 1) so that the neutral valve chamber 36 communicating with the air tank 31 and the first valve chamber 37 communicate with each other. Therefore, the pressure in the air tank 31 is
While being supplied through the first port 18 into the cylinder 16 via the switching valve 30, the same pressure is passed through the first switching valve 30 into the working cylinder 54 of the quick exhaust valve 54 at that port 54.
Supplied through b. At this time, the air discharged from the port 54a of the working cylinder 54 is the second air of the first switching valve 30.
Through the valve chamber 38, the gas is exhausted from the communication holes 42 and 43 to the outside of the valve casing 39 through the inside of the valve body 45.

Then, the piston hammer 28 in the cylinder 16 is moved forward, that is, toward the forging machine 1 by the pressure introduced to the cylinder 16. At the same time, the piston 55 of the quick exhaust valve 51 is
As shown in FIG. 4, the valve body 56 is quickly lifted against the force of the upper coil spring 57.
The passage 52a is opened. Therefore, the space on the front side of the piston hammer 28 in the cylinder 16 communicates with the exhaust holes 53a, 55a through the second port 22 and the passage 52a.
Through a quick exhaust valve 51 through a fixed cylindrical body
Communicated within 53.

Therefore, the air on the front side of the piston hammer 28 is quickly exhausted to the outside of the cylinder 16 as the hammer 28 advances, so that the piston hammer 28 collides with the rear end of the striking rod 26 at a high speed, A striking force is applied to the key 6 via the rod 26 and the jig 27 at its tip. Further, the air in the rod holder 21 is exhausted into the atmosphere through the exhaust hole 23 as the striking rod 26 advances.

In the above impact, the cylinder 16 and the rod holder 21
Positions the piston hammer 28 and the striking rod 26 relative to each other, the piston hammer can be aimed at the striking rod 26 that is in contact with the key 6 through the jig 27.
28 can be collided.

Next, when the operation handle 46 of the first switching valve 30 is returned from the forward position to the return position (see FIG. 6), the valve body 45 is moved forward (to the right in FIG. 1) and the air tank 31 and The neutral valve chamber 36 and the second valve chamber 38 communicating with each other are communicated with each other, and the valve element 45 is separated from the communication hole 41 and opened. Therefore, the pressure in the air tank 31 passes through the first switching valve 30 and enters the working cylinder 54 of the quick exhaust valve 54 through the port 54a.
Valve body 56 closes the passage 52a. In addition,
Along with this, the air discharged from the port 54a of the working cylinder 54 is discharged to the outside of the valve casing 39 through the first valve chamber 37 of the first switching valve 30, the communication hole 41, the inside of the valve element 45, and the inside of the valve body 45. It At the same time, the pressure in the air tank 31 becomes the first switching valve.
It is led to the port 59 of the quick exhaust valve 51 via 30. Also,
At the same time, since the space behind the piston hammer 28 in the cylinder 16 is communicated with the atmosphere through the communication hole 41, the first valve chamber 37, and the first port 18, the passage is provided from the port 59.
The piston hammer 28 is returned by the air pressure of the air tank 31 introduced into the cylinder 16 through 52a and the second port 22 until it comes into contact with the cushioning material 19.

Then, the operation handle 46 is operated again to perform the next impact. That is, the key 6 is hit by repeating the above-mentioned hits as many times as necessary and hitting the key 6.
Can be removed or driven in.

Further, when removing the key 6, when the key 6 begins to come out, it is preferable to reduce the striking force so that the key 6 does not suddenly pop out. In this case, the striking force may be adjusted by stopping the operating handle 46 of the first switching valve 30 before moving the operating handle 46 without moving the handle 46 to the end. Then, the amount of air flowing into the cylinder 16 per unit time can be reduced. Alternatively, the movable cylinder 58 of the quick exhaust valve 51 is rotated to move the exhaust holes 53a and 58a.
This is possible by reducing the communication area of the piston and operating the air brake to move the piston hammer 28.

By the way, when the operation for reducing the striking force is neglected as described above and the same striking force is operated to the end, the key 6 is pulled out at a stretch. Therefore, since the resistance force (the holding force of the key) that prevents the striking rod 26 from moving forward disappears when the key is removed, the striking energy of the striking rod 26 acts on the front end portion of the rod holder 21 in a blank striking state.

However, since the rod holder 21 is provided with anti-air hitting means by the air reservoir 75 and the pressure receiving ring 76, damage to the front end portion of the rod holder 21 can be prevented. In other words, in the idling state, the striking rod 26 advances further to the front position as compared with the normal striking operation, but the large diameter portion 26a collides with the pressure receiving ring 76. Then, the ring 76 is moved forward while compressing the air enclosed in the air reservoir 75, so that the impact energy is absorbed by the air-cushion action. Therefore, since the large diameter portion 26a of the striking rod 26 does not collide with the holder end member 24, the rod holder 21 is prevented from being damaged.

Then, although the key 6 is moved in accordance with the hitting operation described above, the contact state between the jig 27 and the key 6 is still maintained in spite of this. That is, since the pressure of the air tank 31 is continuously applied to the cylinder 62 of the tethering cylinder mechanism 61 from the port 62a, the piston 63 and the piston rod 64 have the same dimensions as the key 6 is moved by the impact. Is moved to the rear. As a result, the mooring cylinder mechanism 61 continues to apply a force in the direction of the forging machine 1 to the entire key striking device 14, so that the key striking device 14
The whole is moved to the forging machine 1 side. Of course, at this time, the striking rod 26 retracts relatively to the rod holder 21,
This backward movement is stopped by the large diameter portion 26a of the striking rod 26 coming into contact with the stopper portion 21b of the rod holder 21.
That is, the contact between the jig 27 and the key 6 is maintained as described above.

Therefore, according to the key striking device 14, it is not necessary to re-align the key 6 with the device each time the striking is performed.
The key 6 can be hit with high workability, and the rod holder 21 can be prevented from being damaged even in the idle driving state. Since it is not necessary to use a forklift truck, the key 6 can be hit without requiring a lot of manpower, and the work can be performed without hitting the key 6 with a large space around the forging machine 1. You can

Needless to say, the present invention is not limited to the above embodiment.

[Effects of the Invention] The key striking device of the present invention described above includes the cylinder, the piston hammer, the rod holder, the striking rod, the first switching valve, and the air tank.
The cylinder and the rod holder relatively position the striking rod and the piston hammer that advances the rod in the key direction by air pressure so that the key can be striking under this restriction, and the tethering cylinder mechanism, the cord connecting member, the tether By providing the rope and the second switching valve,
The entire striking device can be moved toward the forging machine following the movement of the key based on the striking, and the contact state between the striking rod and the key can be maintained. Therefore, according to the device of the present invention, since it is not necessary to re-align the key and the device for each hit, it is possible to hit the key with high workability and it is not necessary to use a forklift truck.
The key can be hit without requiring a lot of manpower, and the key can be hit without requiring a large space around the forging machine. In addition, a pressure receiving ring that forms an air pocket is provided in the rod holder so that the large diameter part of the striking rod collides with the pressure receiving ring when the ball is hit in the idle state. It can be absorbed to prevent damage to the front end of the rod holder.

[Brief description of drawings]

1 to 7 show an embodiment of the present invention, FIG. 1 is a vertical sectional side view of the entire striking device, FIG. 2 is a plan view of the entire striking device, and FIG. 3 is a front view of the entire striking device. FIG. 4 is a longitudinal side view of the quick exhaust valve, FIG. 5 is a plan view of a part of the quick exhaust valve, FIG. 6 is a side view of the entire striking device, and FIG. 7 is a piping system diagram of the striking device. . FIG. 8 is a schematic front view showing a part of the forging machine. 6 …… key, 14 …… key striking device, 16 …… cylinder, 21
...... Rod holder, 26 …… Striking rod, 26a …… Large diameter part, 26b …… Small diameter part, 27 …… Jig, 28 …… Piston hammer, 30 …… First switching valve, 31 …… Air tank, 61 ……
Cylinder mechanism, 64 ...... Piston rod, 65 …… Second switching valve, 67 …… Cable connecting member, 71 …… Tethering line, 75 …… Air reservoir, 76 …… Pressure receiving ring.

Claims (1)

[Claims] 1. An air tank which accommodates a piston hammer movably in a cylinder which is arranged with its axis aligned in the front-rear direction of the forging machine and which reciprocates the hammer in the front-rear direction. Is connected to the cylinder, and the cylindrical rod holder connected to the front end of the cylinder is formed with a large diameter portion at the rear portion, and a small diameter portion on the front side of this large diameter portion is formed on the rod holder of the rod holder. The striking rod is provided so as to project from the front end, and is in contact with the end surface of the key of the forging machine via a jig, and movably supports the striking rod with which the piston hammer collides from the rear, and the rod holder includes the striking rod of the striking rod. A stopper portion for restricting the retracted position is provided, and a sealed air reservoir through which the small diameter portion of the striking rod penetrates is provided in the rod holder in front of the large diameter portion of the striking rod. The pressure receiving ring formed at the position is accommodated so as to be movable in the front-rear direction so as to face the large diameter portion, and the mooring cylinder mechanism having a piston rod protruding rearward of the cylinder is connected to the cylinder. Then, the mechanism and the air tank are communicated with each other through a second switching valve that reciprocates the piston rod in the front-rear direction, and a rope connecting member is connected to the tip end portion of the piston rod, so that when the key is struck. A key striking device for a forging machine, characterized in that each of a plurality of mooring lines whose tip portions are connected to the hooking portion of the forging machine is connected to the above-mentioned cable connecting member.