JPH0325279B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an air cylinder equipped with a mechanism for locking a piston so that it cannot move at the end of its forward stroke, and a press lower die lifting device using the air cylinder. .

Problems to be Solved by the Prior Art and the Invention For example, when deep drawing is performed sequentially using a multi-head press, the workpiece formed at each forming position is taken out from the lower mold, and then the workpiece formed at each forming position is removed from the lower mold at the next forming position. To load the workpiece, the lower die is fixed on the table and the workpiece transfer device is made to move in two dimensions in the horizontal and vertical directions, or the lower die is raised and lowered and the transfer device only moves horizontally. However, if the transfer device is made to move in two dimensions, the drive mechanism will not only be complicated, but it will also be difficult to increase positioning accuracy, resulting in lower processing accuracy. On the other hand, since an extremely large load is applied to the lower mold, raising and lowering it requires a device with high rigidity that can withstand the load, which has the disadvantage of significantly increasing the size.

Purpose of the Invention The present invention was made based on the fact that a large load is applied to the lower mold only when the lower mold stops at an upper position, and that a small driving force is sufficient during lifting and lowering movements. The object of the first invention is to provide an air cylinder equipped with a lock mechanism suitable as a drive source for this lifting device, and the second invention aims to lift and lower the lower die of a press using this air cylinder. The purpose is to provide a device.

Note that the use of the air cylinder according to the first invention is not limited to the lower die lifting device of a press, but is applicable to various air cylinders used when an excessive load is applied only when the piston is stopped. It is possible.

Embodiments Hereinafter, some embodiments of the present invention will be described based on the accompanying drawings.

A first embodiment of the present invention is shown in FIGS. 1 to 3. In the figure, reference numeral 1 denotes a press table, and an air cylinder 2 is mounted on the lower surface of the press table.A spigot 22 protruding from the upper surface of a cylinder head 21 is fitted into a mounting hole 11 and fixed with a bolt 12. A lower mold 13 corresponding to an upper mold 14 fixed to a ram (not shown) is screwed onto the tip of a piston rod 24 that protrudes from a center hole 23 of the piston rod 24 to the upper surface of the table 1.

The air cylinder 2 has a piston 28 tightly and slidably inserted into a cylinder body 20 which is formed by attaching the cylinder head 21 to the upper end of a pipe 25 and a cylinder cap 26 to the lower end thereof, and connecting them together with bolts 27. A lower chamber 20a and an upper chamber 20b are formed below and above the central hole 29.
The reduced diameter portion 30 at the lower end of the piston rod 24 is fitted into the piston rod 24 and fixed with a nut 10,
An annular device groove 31 is formed around the entire circumference of the piston 28, and two sliding holes 32, 32 reaching the center hole 29 are formed on the inner end surface of the device groove 31.
The reduced diameter portion 30 of the piston rod 24 has sliding holes 32, 32 formed at intervals of 180°.
T that communicates with the lower chamber 20a of the cylinder body 20
A letter-shaped ventilation hole 33 is formed. piston 2
As shown in FIG. 3, a pair of semicircular arc-shaped locking bodies 34, 34 are fitted into the device groove 31 of No. 8 tightly and freely slidable in the radial direction. Each sliding hole 3 is provided on the inner peripheral surface corresponding to the locking bodies 34, 34.
A groove 36, which has a circular cross section and bosses 35, 35 that fit tightly and freely into the outer circumferential surface of the groove 36,
A garter spring 37 is wound around the garter spring 36, and the elastic force of the garter spring 37 urges the pair of locking bodies 34, 34 to approach each other and retreat into the device groove 31. A chamfer 39 is formed on both the upper and lower edges of the surface, and a lining 38 with excellent friction properties such as Teflon is formed on the outer peripheral surface and the chamfer 39, and a lining 38 with excellent friction properties such as Teflon is formed on the inner peripheral surface of the cylinder head 21. At the uppermost position where the piston 28 abuts the protrusion 40 on the inner top surface, a fitting groove 41 of the same width is formed around the entire circumference at a position corresponding to the device groove 31 on the outer periphery of the piston 28. There is.
In addition, the cylinder head 21 and cylinder cap 2
6 is formed with an upper port 42 and a lower port 43 that communicate with the upper chamber 20b and the lower chamber 20a, and each port 42, 43 is connected alternately to a pressurized air supply source and the atmosphere via a directional control valve (not shown). It is designed to be connected by switching.

Next, to explain the operation of this embodiment, it is always as follows.
As shown in FIG. 2, the piston 28 is in contact with the inner bottom surface of the cylinder cap 26 and the lower mold 13 is waiting at a lower position. When the work w is supplied to the directional control valve, the lower port 43 is connected to the pressurized air supply source, and pressurized air is supplied to the lower chamber 20a of the cylinder body 20, and the pressure causes the piston 28 to move toward the piston rod. 24 and the lower mold 13 start rising.
At this time, the pressurized air in the lower chamber 20a enters the sliding holes 32, 32 of the piston 28 from the lower end surface of the piston rod 24 through the ventilation hole 33, and enters the sliding holes 32, 32 of the piston 28.
5, 35, the locking bodies 34, 34 are separated from each other against the elastic force of the garter spring 37, protrude from the device hole 31 in the radial direction, and are pressed against the inner peripheral surface of the cylinder body 20. There is a lining 38 on its outer circumferential surface.
is formed, so the sliding resistance is small.
The piston 28 rises smoothly. When the piston 28 reaches the uppermost position and contacts the protrusion 40 on the inner top surface of the cylinder head 21, chamfers 39, 39 are formed on both upper and lower edges of the outer periphery of the locking bodies 34, 34. As shown in FIG. 1, the locking body 34,
The tip of the piston 34 smoothly fits into the fitting groove 41 of the cylinder head 21 due to the pressing force of the pressurized air acting on the bosses 35, 35, and the piston 28 is locked so that it cannot be raised or lowered. At this time, the piston rod 24 reaches the uppermost position and the lower die 13 supports the work w held by the transfer device from below, and the transfer device retreats to the side, and the upper die 14 descends together with the ram. Then, the work w is pressed between the lower mold 13 and molded, and the pressing force of the ram acting at this time is due to the locking body 34 fitted in the device groove 31 and the fitting groove 41. , 34, so
The piston 28 is held stationary without descending. When the molding is completed and the upper mold 14 rises together with the ram, the transfer device enters from the side to hold the work w, and the lower port 43 is moved by the operation of the directional control valve.
When is communicated with the atmosphere, the pressure in the lower chamber 20a of the cylinder body 20 decreases, and the pressure in the sliding holes 32, 32 of the piston 28 also decreases, so that the locking body 3
4 and 34 are drawn toward each other by the elastic force of the garter spring 37, and are drawn into the device groove 3 from inside the fitting groove 41.
1, the lock is released, and the upper port 4
2 is connected to a pressurized air supply source and the cylinder body 2
When pressurized air is supplied to the upper chamber 20b, the pressure causes the piston 28 to move toward the piston rod 24
The work w is then lowered together with the lower die 13, and the workpiece w is transferred to the next process by the horizontal movement of the transfer device.

The second embodiment of the present invention shown in FIGS.
A communication hole 44 is formed between the piston rod 2, 32 and the ventilation hole 33 of the piston rod 24, and a large diameter hole 45 at the bottom and a small diameter hole 46 at the top, which are perpendicular to the communication hole 44, are formed so as to penetrate from the bottom surface of the piston 28 to the top surface. A conical seat surface 47 is formed in a portion perpendicular to the communication hole 44, and a large diameter portion that fits tightly into the large diameter hole 45 and a small diameter portion that tightly fits into the small diameter hole 46 are formed concentrically. A valve rod 48 having a conical valve body 49 in close contact with the seat surface 47 is slidably fitted between the piston 28 and the piston 28, and is fixed by a nut 50 to the upper end protruding from the upper surface of the piston 28. A compression coil spring 52 is installed between the ring 51 and the upper surface of the piston 28, and as shown in FIG. 47 and closes the communication hole 44. Therefore, as shown in FIG. 5, when the piston 28 is at the lowermost position and during the upward stroke until reaching the uppermost position, the sliding holes 32, 32 are inserted into the lower chamber 20a of the cylinder body 20. No pressure is applied, and the locking bodies 34, 34 are drawn together by the elastic force of the garter spring 37 and retreat into the device hole 31 of the piston 28, and their outer peripheral surfaces are pressed against the inner peripheral surface of the cylinder body 20. I can't. Therefore, the piston 28 operates smoothly even without forming the lining 38 on the outer peripheral surfaces of the locking bodies 34, 34 as in the first embodiment. The piston 28 is connected to the protrusion 4 on the inner top surface of the cylinder head 21.
0, the upper end of the valve lever 48 comes into contact with the inner top surface of the cylinder head 21 and is prevented from rising, causing the valve lever 48 to move against the piston 28 while elastically contracting the compression coil spring 52. , the valve body 49 separates from the seat surface 47, the communication hole 44 opens, and the pressurized air in the lower chamber 20a flows from the ventilation hole 33 into the sliding holes 32, 32. Pressure acts on the bosses 35, 35 and the locking bodies 34, 34
are pushed away from each other against the elastic force of the garter spring 37, as shown in FIG.
When the piston 28 reaches the uppermost position where it comes into contact with the protrusion 40 on the inner top surface of the cylinder head 21, the outer peripheral portions of the locking bodies 34, 34 fit into the fitting groove 41 of the cylinder head 21, and the first As in the embodiment, the piston 28, the piston rod 24 connected thereto, and the lower die 13 are locked so that they cannot move, and in this state, the upper die 14 is lowered together with the ram to form the workpiece w. After the molding is completed, when the lower port 43 is communicated with the atmosphere by the operation of the directional control valve, the pressure in the lower valve chamber 20a and in the sliding holes 32, 32 decreases, and the pressure acting on the bosses 35, 35 is released. The locking bodies 34, 34 are retracted into the device groove 31 by the elastic force of the garter spring 37, and the lock is released. Then, when pressurized air is supplied from the upper port 42 to the upper chamber 20b, the pressure causes The piston 28 descends together with the piston rod 24 and the lower die 13, and at the beginning of its downward stroke, the upper end of the valve rod 48 separates from the inner top surface of the cylinder head 21, and is pushed against the piston 28 by the elastic expansion force of the compression coil spring 52. and the valve body 4 rises relatively.
9 comes into close contact with the sheet surface 47 and closes the communication hole 44, returning to the state shown in FIG.

In the third embodiment of the present invention shown in FIGS. 6 and 7, contrary to the first and second embodiments, a device groove 31 is formed on the inner peripheral surface of the cylinder head 21, and two grooves are formed on the inner peripheral surface of the cylinder head 21. The sliding holes 32, 32 are formed in a semicircular arc shape as shown in FIG. 7, and a lining 38 is provided on the inner peripheral surface.
A pair of locking bodies 34, 34 having chamfers 39, 39 on both upper and lower edges thereof are fitted into the device groove 31, and a protrusion is formed on the outer peripheral surface of each locking body 34. A boss 35 having a circular cross section is tightly fitted into each sliding hole 32, and compression coil springs 53, 53 are interposed between the corresponding end surfaces of both locking bodies 34, 34, so that their elastic expansion force causes them to mutually The device groove 31 is spaced apart.
A fitting groove 41 is formed in the outer peripheral surface of the piston 28 at its uppermost position corresponding to the device groove 31, and each sliding hole 32
and the lower chamber 20a of the cylinder body 20 through the ventilation pipe 5.
4, and when pressurized air is supplied to the lower chamber 20a, the pressure causes the piston 28
As the pressure increases, the pressure acts on the sliding holes 32, 32 through the ventilation pipe 54, and the bosses 35, 35
By pressing , the locking bodies 34, 34 are pressed against the outer peripheral surface of the piston 28, and as shown by the solid line in FIG. 6, the piston 28 reaches the uppermost position and the fitting groove 41 is aligned with the device groove 31. Then, the locking body 3
4 and 34 are fitted into the fitting groove 41, the piston 28 is locked so that it cannot move, and the lower chamber 20a is opened to the atmosphere by the operation of the directional control valve.
The pressure inside the sliding holes 32, 32 also decreases, and the locking body 3
4 and 34 are separated from each other and retreated into the device groove 31 by the elastic expansion force of the compression coil springs 53 and 53, and the lock is released, so that pressurized air is supplied to the upper chamber 20b. It is lowered to the lower position shown by the chain line in FIG.

In the fourth embodiment of the present invention shown in FIGS. 8 and 9, locking bodies 34, 34 are fitted into a device groove 31 formed on the outer periphery of a piston 28, as in the first and second embodiments. The actuating rod 56 is tightly and slidably fitted into the guide hole 55 penetrated through the upper and lower surfaces of the piston 28 while being urged in the direction of retreating into the device groove 31 by the elastic force of the garter spring 37. An engaging piece 57 is provided in the guide groove 59 that is connected to the upper part of the guide hole 55 and that is formed in the center of the operating rod 56.
A boss 35 protruding from the locking body 34 is fitted into the sliding hole 32 formed to communicate the device groove 31 and the guide groove 59, and an upward slope 60 formed at the tip thereof. and a downward slope 58 formed on the engagement piece 57 are in contact with each other. A fitting hole 61 is formed in the inner top surface of the cylinder head 21 directly above the operating rod 56, and a fitting hole 61 is formed with a diameter-reducing step 62 at the opening at the lower end, and a small piston 63 is tightly and freely slidably inserted into the fitting hole 61. A first compression coil spring 65 with a small spring constant is installed between the lower surface of the fitting and a collar 64 formed at the upper end of the operating rod 56, and the upper surface of the small piston 63 is installed in the fitting hole 61. A second compression coil spring 66 with a large spring constant is attached to press the fitting hole 61, and the fitting hole 61 is open to the atmosphere through a ventilation hole 67.

To explain the operation of this embodiment, from the state shown in FIG. 9 in which the piston 28 is in the lower position, the lower chamber 2
When pressurized air is supplied to 0a and it rises, the first compression coil spring 65 is gradually compressed and its elastic expansion force increases, and the force with which the slope 58 of the engagement piece 57 presses the slope 60 of the boss 35 increases. When the locking bodies 34, 34 overcome the elastic force of the garter spring 37, they rise while being pressed against the inner peripheral surface of the cylinder body 20, and as shown in FIG. 8, when the piston 28 reaches the uppermost position, The operating rod 56 descends and the locking bodies 34, 3
4 fits into the fitting groove 41, and the piston 2
8 and the piston rod 24 are locked so that they cannot be raised or lowered. Then, the lower chamber 20a is opened to the atmosphere,
When the upper chamber 20b is connected to a source of pressurized air,
In addition to the elastic expansion force of the first compression coil spring 65, the pressure of the pressurized air in the upper chamber 20b acts on the lower surface of the small piston 63 to overcome the elastic expansion force of the second compression coil spring 66. This is compressed and small piston 6
3 rises in the fitting hole 61 as shown by the chain line in FIG. Due to the elastic force of 37, the slope 60,5
8, the operating rod 56 is pushed up and the device groove 3 is pushed up.
1, the lock is released and the piston 28
and the piston rod 24 descends. When the upper chamber 20b is opened to the atmosphere, the small piston 63 is lowered to its original position where it abuts the diameter-reducing step 62 by the elastic expansion force of the second compression coil spring 66.

The embodiment of the present invention shown in FIG. 10 is a modification of the fourth embodiment, in which the second compression coil spring 6
6 is removed, and the fitting hole 61 is communicated with the lower chamber 20a through the ventilation pipe 68, and the piston 28
During the upward stroke, the pressurized air in the lower chamber 20a acts on the upper surface of the small piston 63 to hold it in the lower position, and when the lower chamber 20a is opened to the atmosphere, the first
The compression coil spring 65 pushes up the small piston 63 and expands, and due to the decrease in the elastic expansion force, the locking body 34
is retracted into the device groove 31.

In a fifth embodiment of the present invention shown in FIG. 11, a cylindrical fixing body 70 is integrally fixed to the outer end surface of a cylinder head b of a conventionally known air cylinder a with bolts c, and protrudes from the cylinder head b. A thick disk-shaped movable body 71 that tightly fits into the inner circumferential surface of the fixed body 70 is inserted into the protrusion of the piston rod d through the center hole 78.
A pair of locking bodies 75, 7 are fitted into a device groove 72 formed on the outer circumferential surface of the movable body 71 and formed into a semicircular arc shape.
Garter spring 7 fitted with 5 and wrapped around the outer periphery
The elastic force of 9 urges them toward each other,
A boss 76 protruding from the inner circumferential surface of each locking body 75 is tightly fitted into a sliding hole 73 formed transparently from the deep end surface of the device groove 72 to the center hole 78. A ventilation hole 74 communicating with the chamber e and the sliding hole 73 is formed, and the piston rod d
At the uppermost position, the device groove 72 of the movable body 71
A fitting groove 8 of the same width is formed on the inner peripheral surface of the fixed body 70 corresponding to
0, and its operation is based on the first
Same as the example.

In this embodiment, the lock mechanism of the first embodiment is provided on the outer surface of the cylinder head of a conventionally known air cylinder, but the structure of this lock mechanism is similar to that of the second to fourth embodiments. may be replaced with

Structure and effects of the invention As specifically explained in the above embodiments,
The air cylinder of the first aspect of the present invention has a piston tightly and slidably fitted into a cylinder body, and a piston rod connected to the piston protrudes from at least one end of the cylinder body. Either a predetermined position on the inner peripheral surface of the main body and the outer peripheral surface of the piston, or a corresponding surface between a fixed body protruding from the end face of the one end side of the cylinder body and a movable body fixed to the protruding part of the piston rod. A device groove is formed on one side and a fitting groove is formed on the other side, and a locking body that can enter and retreat into the fitting groove and is biased in the backward direction by a spring force is fitted into the device groove. At the end of the forward stroke of the piston, the locking body enters and moves into the corresponding fitting groove due to the pressure of pressurized air for driving the piston or spring elasticity supplied to the cylinder body. The apparatus is configured such that the locking body is locked in a manner that it cannot be locked, and the locking body is retracted into the device groove and the lock is released by switching the pressurized air before the piston starts to move back. hand,
At the end of the forward stroke of the piston, the locking body fits into the fitting groove and locks the piston so that it cannot move up or down, and the load acting on the piston rod is received by the locking body, so the thickness of the locking body can be increased. By doing so, it is possible to withstand large loads, and since the locking body advances and retreats in a direction perpendicular to the direction in which the load is applied when the piston is stationary, a large force is not required to drive it. Since the locking body is retracted into the device groove by switching the pressurized air for driving, no other driving source is required, and the structure can be made small and simple. Further, a lower mold elevating device for a press according to a second invention of the present invention uses the air cylinder according to the first invention as a lower mold elevating device, and the lower mold is moved to an upper molding position. Since the workpiece can be raised and lowered to the lower retracted position, the workpiece transfer device only needs to move in the horizontal direction.The structure is simple, the positioning accuracy is high, and the large loads that are applied during molding can be avoided. can be received by the locking body, and press molding can be reliably performed without using any other locking device.

[Brief explanation of the drawing]

Figures 1 and 2 are sectional views showing the operation of the first embodiment of the present invention, Figure 3 is a perspective view of the locking body, and Figures 4 and 5.
The figure is an enlarged sectional view of a part showing the operation of the second embodiment of the invention, FIG. 6 is an enlarged sectional view of a part of the third embodiment of the invention, and FIG. 7 is a perspective view of the locking body. , 8th,
FIG. 9 is a partially enlarged sectional view showing the operation of the fourth embodiment of the present invention, FIG. 10 is a sectional view of a modification thereof, and FIG.
FIG. 1 is a sectional view of a fifth embodiment of the present invention. 1: Table, 2: Air cylinder, 13: Lower mold, 14: Upper mold, 21: Cylinder head, 24:
Piston rod, 20: Cylinder body, 20a:
Lower chamber, 20b: Upper chamber, 28: Piston, 3
1: Device groove, 32: Sliding hole, 33: Ventilation hole, 3
4: Locking body, 35: Boss, 37: Garter spring, 41: Fitting groove, 44: Communication hole, 47: Seat surface, 48: Valve rod, 49: Valve body, 53: Compression coil spring, 55: Guide hole, 56: operating rod, 57: engaging piece, 58, 60: slope, 61: fitting hole, 63: small piston, 65: first compression coil spring, 66:
2nd compression coil spring, 70: fixed body, 71: movable body, 72: device groove, 73: sliding hole, 75: locking body, 76: boss, 79: garter spring, 8
0: Fitting groove, a: Air cylinder, b: Cylinder head, d: Piston rod, w: Work.

Claims (1)

[Scope of Claims] 1. An inner periphery of the cylinder body of an air cylinder in which a piston is tightly and slidably fitted into the cylinder body, and a piston rod connected to the piston protrudes from at least one end of the cylinder body. A device groove is formed in either a predetermined position of the surface and the outer peripheral surface of the piston, or a corresponding surface between a fixed body protruding from the end face of the one end side of the cylinder body and a movable body fixed to the protrusion of the piston rod. and a fitting groove is formed on the other side, and in the device groove,
A locking body that can enter and retreat into the fitting groove and is biased in the backward direction by a spring force is fitted, and when the piston reaches the end of its forward stroke, the locking body engages with the cylinder body. The supplied pressurized air for driving the piston enters the corresponding fitting groove due to the pressure or spring elasticity and is locked so that it cannot move. An air cylinder equipped with a locking mechanism, characterized in that the locking body is retracted into the device groove to release the lock. 2. A piston is tightly and slidably fitted into the cylinder body, and a piston rod connected to the piston is protruded from at least one end of the cylinder body at a predetermined position on the inner circumferential surface of the cylinder body. A device groove is fitted into either the outer peripheral surface of the piston or the corresponding surface between the fixed body protruding from the end face of the one end side of the cylinder body and the movable body fixed to the protrusion of the piston rod, and the device groove is fitted into the other. forming grooves, respectively, in the device grooves;
A locking body that can enter and retreat into the fitting groove and is biased in the backward direction by a spring force is fitted, and when the piston reaches the end of its forward stroke, the locking body engages with the cylinder body. The supplied pressurized air for driving the piston enters the corresponding fitting groove due to the pressure or spring elasticity and is locked so that it cannot move. An air cylinder configured to release the lock by retracting the locking body into the device groove is attached to the table of the press with the piston rod facing upward, and the tip of the piston rod corresponds to the upper die fixed to the ram. A lower mold elevating device for a press, characterized in that the lower mold is fixed.