JPH0446680B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a press apparatus for molding various articles.

(Prior Art) A method for controlling programmed speed and force in compression molding using a large press using a servo controller for actuation is disclosed in U.S. Pat. No. 4,076,780.
No. 5, which shows a mechanically actuated press device to drive the ram of the press, but uses a hydraulic cylinder for final mold closure. This controls the inclination of the mold and keeps the mold halves parallel.

U.S. Pat. No. 3,531,830 discloses an apparatus for producing molded articles with cam elements for adjusting the position of a stop that controls the movement of a molding press in the final molding operation. Further, a mold press equipped with a retractable wedge member controlled by a hydraulic cylinder is disclosed in US Pat. No. 3,802,818, and a molding machine is disclosed in US Pat. No. 2,722,174 and US Pat. Hydraulic servo press controlled folding is disclosed in US Pat. No. 3,825,386.

PROBLEM TO BE SOLVED BY THE INVENTION The applicant has made various developments in the field of hydraulic servo control devices, including control mechanisms for various devices having rigid tables that must be properly maintained with respect to a reference plane. I went. For example, US Pat. No. 3,800,588 relates to a servo controller that provides multiple degrees of freedom to a rigid structure, and US Pat. No. 3,918,298 relates to improvements in such a servo controller. Furthermore, the applicant has also developed a hydraulic bearing and its control device. For example, US Pat. No. 3,921,286 and US Pat. No. 3,992,978. Furthermore, in US Pat. No. 3,994,540 an external height control device for a hydraulic bearing was also disclosed.

A hydraulic cutting press that deep-draws aluminum cups to make cans has been patented in the U.S.
No. 3,908,429 and an adjustable press frame construction is disclosed in U.S. Pat. No. 4,063,453.

An object of the present invention is to provide a press device that molds a workpiece using an upper mold half and a lower mold half, in which the positional relationship between both mold halves can be easily adjusted. It's about doing.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the press device of the present invention has the following configuration. That is, the frame 15
The frame 15 has a base member 16 and a crosshead assembly 3 mounted on the frame 15 and spaced apart from the base member 16.
6, the base member 16 supports the lower platen assembly 26, and the crosshead assembly 3
6 to support the upper mold half 30,
The press apparatus includes a hydraulic actuator 75 that causes the lower mold half 31 to be supported on the lower platen assembly 26 and further includes a hydraulic actuator 75 that applies a force that causes the upper and lower mold halves 30, 31 to close. An actuator 75 is disposed between the base member 16 and the lower platen assembly 26 , the hydraulic actuator 75 having an actuator surface facing the lower platen assembly 26 and having a sealing means 8 on the actuator surface.
3 is mounted, and the sealing means 83 presses against the surface of the lower platen assembly 26 to create a cross section between the actuator surface and the surface of the lower platen assembly 26 that is smaller than the effective area of the hydraulic actuator 75. A passage 8 is defined between the interior of the hydraulic actuator 75 and the chamber.
4 is provided, and the passage is configured to supply pressure fluid from the interior of the hydraulic actuator 75 into the chamber to statically support the lower platen assembly 26, whereby the static pressure support , during the pressing process, the lower mold half 3
1 is movable in a plane parallel to the plane of the lower platen assembly 26,
It is a press device.

As described above, according to the press apparatus of the present invention, the lower mold half is statically supported with respect to the upper mold half, and the lower platen assembly is installed so that the mold half does not receive side loads during the pressing process. Because they are movably supported in a plane parallel to the plane of the solid body 26, these mold halves are not subject to side loads that could easily cause misalignment of the mold halves.

Furthermore, if the press apparatus of the present invention is provided with a plurality of take-out actuators and the fluid actuator for driving the lower platen assembly is retracted by these take-out actuators, the press operation of the press apparatus, In particular, the opening operation of the mold halves can be made more reliable.

Also, assuming a pair of axes that are parallel to the dividing plane of the upper and lower mold halves and perpendicular to each other, the movement of the mold halves in the direction along these axes and the movement around these axes are calculated. The reliability of the operation of the press is improved if each movement is controlled to avoid side loads that tend to cause misalignment of the mold halves.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown, a compression molding press frame 15 is supported on a base member 16 and generally includes four smooth upright posts 17.
and an upper platen assembly 20 on these columns.
is installed. Upper platen assembly 20 is movable vertically along column 17 by a pair of single-acting lift actuators 22, each of which is located at each end of the press, with a proximal end connected to base member 16. 23 and an extendable rod 24 attached at 25 to the opposite end of the upper platen assembly 20. An LVDT 27 is connected to actuator 22 and measures the displacement of rod 24 for feedback.

Lower platen assembly 26 is supported by base member 16 as described below. The compression molding assembly includes an upper mold half 30 and a lower mold half 31 mounted between upper and lower platen assemblies. The upper mold half is mounted or bolted to the upper platen assembly in any desired manner, and the lower mold half is supported to the plate of the lower platen assembly by bolts or other suitable means. This will be discussed later.

Turning now to the upper platen assembly 20, as best seen in FIGS. 3 and 4, the upper platen assembly 20 includes a flat plate 35 fixedly attached to a crosshead assembly 36. As shown in FIGS. The crosshead assembly 36 consists of a plurality of large shear webs 37 (four shown) consisting of parallel, spaced apart, generally rectangular plates.
A box portion is formed in the central portion 40 of the crosshead assembly or crosshead 36 by welding vertical connecting plates 41 between adjacent shear webs 37. The shear web 37 has a boss 42 at its lower edge, and a plate 41 extends from the plane defined by the lower end of the boss 42 to the upper edge of the shear web 37. The lower edge of boss 42 defines a plane spaced from the lower edge plane of the side portions of shear web 37.

The plate 35 is welded in contact with the lower edge of the boss 42 of the shear web 37. The outer parts of the plate 35 (outer parts of the boss and the vertical plate 41) are held by suitable reinforcing webs which transfer the loads from the edges of the plate towards the central part 40. It has reinforcing webs 43 which are connected to the outer shear web 37.
As shown, these reinforcing webs are connected to web 37.
It consists of a triangular plate extending at an angle to the plane of the plane.

Further, an appropriate number of central reinforcing webs 44 are provided between the two central shear webs 37. Webs 44 extend laterally outwardly from central portion 40 toward the edges of plate 35 and each side thereof. These webs 44 are also triangular in shape and transmit loads from the edges of the plate 35 to the box portion 40 of the crosshead.

As shown, such an arrangement separates the upper surface 35A of plate 35 from the lower edge of shear web 37 except along boss 42, which is spaced apart from central box portion 40 formed by vertical plate 41. defines the lower surface of

Accordingly, the outer edges 35B along the sides of the plate 35 and the outer end portions 35C along the edges of the plate 35 cantilever from the central box portion 40. web 4
3 and 44 represent the bending load near the outer edge of the plate 35 on the plate 41.
and thus to the central part of the shear web 37 forming the upper crosshead. This load support greatly improves the deflection characteristics of the upper crosshead against forming loads, as will be discussed below.

Next, the clamp of the upper crosshead assembly will be described. The upper crosshead assembly 36 is
As previously mentioned, lift actuator 22 allows movement along column 17. The lift actuator is a single acting actuator as described above. This is because the weight of the crosshead causes the actuator to retract when pressure is released from the base of the actuator. The rate of downward movement of the crosshead is controlled by regulating the fluid exiting the base of actuator 22.

In a mold operation, if the crosshead is lowered after the material to be formed has been placed between the mold halves, it is necessary to clamp the upper crosshead and therefore the upper mold half 30 of the mold and the upper platen in place. be. The apparatus of the present invention uses a clamping member that firmly and reliably clamps the upper platen to the post 17. These clamping members extend laterally into and out of the crosshead assembly to facilitate installation of the long posts 17 and eliminate the need for large vertical openings for insertion and removal of the posts themselves. It can also slide in any direction.

The clamps are hydraulically driven and operate parallel to each post 17 at each end of the crosshead assembly 36. The crosshead shear webs 37 are spaced apart as described above, and each post and post clamp has two
located within the space between the two shear webs. The clamping member includes a split clamp 46. Split clamp 46 is made of an elongated block of steel having a length substantially equal to the vertical height of shear web 37. Split clamp 46 has a bore 47 that accommodates one of the posts 17. Bore 4 with wear-resistant bearing sleeve
It's good to line 7. The clamp is split longitudinally and has a slot 48 in the outer edge of the cartridge 46 of the split clamp, which slot communicates with a bore 47.

The side surfaces of the clamps 46 are flat surfaces that slide within the spaces between adjacent shear webs 37. Each clamp member 46 has three cross holes (aligned with slots 48) that are vertically spaced apart and adapted to receive actuator rods 52, each of which has a It is operatively coupled as a crosshead locking actuator. Rod 52
spans the full width of the crosshead, so 4
It passes through all three shear webs 37 (clearance openings for the rods being provided, of course) and through two clamp members 46 at each end of the crosshead. Each rod 52 is attached to a suitable load-bearing collar member 53 on the outside of one of the outer shear webs 37.

The opposite end of the rod 52 connects to a movable hydraulic actuator block 5 located externally of the outer shear web 37 on the opposite outer side of the crosshead.
It is attached to 4. As shown in FIG. 6, actuator block 54 has an annular cylinder opening 55. As shown in FIG. The opening 55 is an annular or toroidal cylinder. An annular living piston 56 is mounted in each cylinder opening 55 and is secured to the outer shear web 37 at the side of the crosshead. One living piston surrounds each rod 52.

Each slot 48 has one or more clamp release actuators 60 (FIG. 6). These actuators 60 include a piston 58 and a cylinder member 5.
9, each of which is suitably located on one surface of slot 48. There are typically two such release actuators on the force clamp 46. When hydraulic pressure is applied to cylinder 59, slot 48 opens thereby releasing the respective clamp from post 17 by opening bore 47. The clamp actuator operates in parallel and the release actuator also operates in parallel.
Since one actuator must be released when the other actuator is actuated, one valve may not be provided for these actuators.

Two central shear webs 3 to prevent excessive deflection of the shear web when the clamp is actuated
A spacer tube 61 is placed on the rod 52 at a distance of 7. When pressurized fluid is supplied to the actuator cylinder 55, tension is exerted on the rod 52, which acts through the piston 56 on the outer surface of the shear web 37 on the side of the crosshead, and the collar 53 responds to the tension on the rod 52. and transmits this to the crosshead so that the tensile load of the rods pulls all the shear web ends towards each other, thereby compressing the clamp 46 and clamping the crosshead firmly on the upright post 17. Spacer tube 61 prevents the two central webs 37 from constricting towards each other. The block 25 shown in FIG. 3 is a rod 24 for the cylinder 22.
It is for installation.

The feature of the clamp of the present invention is that the cylinder member 54
and that the rod 52 can be removed. The cylinder member 54 and rod 52 can be removed.
The cylinder member 54 is threaded onto the rod, which can be released from the collar 53 by longitudinally pulling it out. When the rod is released from the collar, the crosshead clamp member 46 can slide laterally out of the end of the crosshead (after removing the retaining cap screw 57). Shear web 37 defines a slot leading to the end of the crosshead.
The post 17, together with the clamp, can be swiveled to the side as shown in phantom in FIG. 4 for installing or removing the post through the crosshead. The column 17 is attached to the base 1 to allow the column to swing for installation and removal.
Can be bolted to 6.

The crosshead assembly is suitably supported during installation. However, the crosshead assembly
Eliminates the need to install extremely tall towers for vertical removal of columns 17 or holes to drop columns 17 for repair and removal of crosshead assemblies. As shown in FIG.
2 is used to limit the amount of expansion of the clamp 46. The strap returns from two parts 62A, 62B, which are held together by cap screws. The clamp has an elongated opening 62 at its end.
C and the installation of studs 62D on the clamps 46 at both ends of the slots 48. These studs pass through openings in the straps of the clamp, and the ends of these openings engage the studs to prevent the clamp from opening excessively. Two parts 62A, 62B
is stopped at 62E to control the amount of expansion.

The attachment of plate 35 to the crosshead assembly relimits the deflection of the plate during use in a manner advantageous to the operation of the forming press. It has long been desirable to use extremely stiff plates and crossheads to minimize deflection due to forming loads for the same amount of steel and weight as in conventional support systems. The rigid central portion of the assembled plates extends approximately half the distance between the columns of the set, while the outer ends of the shear webs 37 are arranged such that the webs have virtually unlimited fatigue during clamping operations. It can be fully flexed in the lateral direction. The design is extremely effective. The deflection characteristics compared to a conventional crosshead that is simply clamped at both ends and supports a plate or platen between the ends is shown in FIG.

Next, the deflection of the crosshead will be explained.
In FIG. 5, the deflection curve for a normally supported crosshead is shown at 63. Maximum deflection occurs at the center of the platen, and the amount of deflection decreases toward the crosshead portion of the column. However, when subjected to a load as shown by arrow 64 in FIG. 4, the crosshead deflection curve shown in FIGS. 3 and 4 becomes as shown at 65 in FIG. With respect to the reference line shown at 66, it can be seen that at the center of curve 65 the amount of deflection of plate 35 is substantially the same as that of a normally supported crosshead (curve 63). However, the amount of deflection of the plate 35 increases again at the outer edge. The reason is that the outer edge of the plate 35 has webs 43 and 44 instead of the web 37.
This is because it is supported by The deflection of the plate from the reference line is not reduced compared to that of the ordinary design, but
Deflection or distortion from the best plane is substantially reduced. Therefore, mold distortion (deflection) is reduced, which is beneficial with compression molding operations.

For a crosshead of conventional design, normally supported at the outer end, having the same amount of steel and weight as a multi-web crosshead assembly, the best out-of-plane deflection will not be as useful for forming operations as the present invention. Must not be.

Next, control of the crosshead assembly will be explained. The control circuit unit for the lift actuator 22 is shown schematically in FIG. This unit is servo-controlled and has a program controller 67 for providing overall program control and a servo controller 69 for controlling a servo valve 68 (which may be a three-way valve) as a function of the program.
The signal coming along line 27A from 27A indicates the position of the crosshead. Single acting actuator 22
On the other hand, the servo valve 68 is connected to the actuator 22
The proximal end of the crosshead is connected to a pressure source via parallel lines 68A, or these lines are connected to an outlet to lower the crosshead under its own weight under control of the actuator's liquid flow rate.

The program controller 67 coordinates motion in the mold operation which is also controlled by hydraulic actuators operating under servo control. If necessary,
A pilot operated check valve can be used to prevent actuator 22 from being pulled back.

The clamp cylinder 55 of the actuator block 54 is controlled by a four-way valve 60A, the clamping force is released before and during operation of the crosshead, and the actuator 60 is activated when the actuator block 54 is released. . Valve 60A
may be used to control six clamp cylinders (clamp actuators) in parallel and eight release actuators 60 in parallel. The clamp actuator and release actuator consist of single acting cylinders. Valve 66A may be controlled by a DC electrical signal along line 70.

Turning now to the lower platen assembly, this assembly 26 consists of a heavy plate supported relative to the base member 16. Base member 16 is a structure strong enough to support the loads during mold operations.
The lower platen assembly is used to load the lower mold half 31, and the loading of the lower mold half 31 with respect to the lower platen assembly occurs during a mold cycle once the crosshead is locked in the mold position. , such that the lower platen assembly is moved upwardly by a controlled force from a servo-controlled hydraulic actuator.

Figures 8 and 9 show a partially schematic lower platen assembly.

Lower platen assembly 26 is mounted to the upper surface of base member 16 and includes a platen 72 of bolsters for supporting lower mold half 31. The molding or compression force is achieved through the use of hydraulic actuators 75, each having an outer cylinder housing 76 and an inner piston 77 secured in place on the base member 16. Inner piston 77 has an annular flange 78 forming a partially spherical or short cylindrical surface with sufficient clearance to raise piston 77 with respect to the cylindrical side wall of cylinder cavity 79 . A seal ring is attached to the groove of this annular flange to seal the piston. The platen 72 is supported by a hydrostatic support plate 81 from which it is vertically removable. The platen 72 has narrow but precisely sized grooves 82.
at the bottom, and tapered pins fit into these grooves 82 so that when the plate 81 supports the platen or bolster 72, the two parts cannot slide relative to each other. However, when the pin is pulled out vertically, the platen 72
can move about. A seal ring 83 (made of elastomer) attached to the groove of each piston 77 defines an annular space on the lower surface of the plate 81. The passage 84 is connected to the cavity 7 inside each actuator.
9 leads into an annular space defined by a sealing ring 83 . When the actuator is pressurized, the hydraulic pressure supports the support plate under static pressure support. The diameter of ring 83 is adjusted to ensure proper operation of piston 7.
7 effective diameter. The pressure of the hydrostatic supports is the same as the pressure within the cavity 79, and the hydrostatic supports (these are provided by four actuators 75 as shown) prevent the mold halves from forming even under molding forces. The platen 72 and plate 81 can be easily moved to properly position the platen 72 and plate 81. The support pressure in the support area defined by ring 83 is a function of the forming force and therefore the load carried by platen 72.

That is, by this static pressure support, the base member 1
6 supports the lower platen assembly 26.
The hydrostatic bearing includes at least one hydraulic actuator 75 located between base member 16 and lower platen assembly 26 . These hydraulic actuators 75
has an actuator surface (corresponding to the top surface of piston 77) facing lower platen assembly 26, on which a seal ring 83 is mounted. This seal ring 83
As a result, a chamber having a cross-sectional area smaller than the effective area of the hydraulic actuator 75 is defined on the actuator surface. This seal ring 83 presses against the surface of the lower platen assembly 26. and,
A passageway 84 is provided between the interior of each hydraulic actuator 75 and its chamber defined by seal ring 83, which allows access from the interior of the hydraulic actuator to its corresponding chamber. A pressure fluid is provided to provide hydrostatic support for the lower platen assembly.

Thus, the platen 72 can move in the Y-axis (back and forth) on the hydrostatic support (within the limits that can be provided mechanically by the heel block) and can also move in the X-axis (laterally). be able to. The X-axis direction and Y-axis direction are indicated by arrows X and Y in Figure 9.
Each is shown in . The platen 72 is also capable of oscillating motion, ie, circular motion about the axis of the central axis of the piston 77 (indicated by the arrow "yaw" in FIG. 9).

Additionally, the platen 72 must be controlled against "pitch", which is rotational movement about an axis extending in the front-to-back direction and parallel to the top surface of the platen. This vertical wobbling is indicated by the arrow "pitch" in FIG.
The platen undergoes roll motion or "sway" about an axis extending laterally through the center plane of the platen 72.
This lateral wobbling is indicated by the arrow “roll” in Figure 2.
Shown in

The above-mentioned X-axis movement, Y-axis movement and rocking movement (three degrees of freedom) are controlled by a heel block 90 on the mold half, as shown in FIG. These heel blocks 90 are interlocking blocks on the mold itself to provide proper attachment of the mold halves and ensure proper wall thickness of the molded article. Heel block 9 like this
0 fits into the guide groove 91 of the other mold half. As shown, a heel block is provided in the upper mold half 30 and a corresponding guide groove 91 is provided in the lower mold half 31. In the illustrated embodiment, four heel blocks and guide grooves are provided and used for guidance. The mold half can no longer rotate about the vertical axis (yaw) and movement in the X and Y axes is restricted. These movements are prevented when the block is finally placed in position.

There are four hydraulic actuators 75 on the lower surface of the lower platen assembly which, as previously described, are single acting actuators that support the lower platen assembly and support the crosshead assembly. After being locked in its proper position, the lower mold half is pushed up into contact with the upper mold half. Very little spring back is important to separate the mold halves without damaging the article. A total of four separation or extraction actuators 95 are provided, one at each corner. These actuators are also single acting and operate to separate the lower mold half from the upper mold half, and at the same time these actuators 95 must retract the piston 77 of actuator 75. This movement is a relatively small distance for separation purposes only, and therefore there is little bounce in the direction of the load, reducing the risk of damaging the molded article.

Therefore, separation by the take-off actuator 95 has a very short oil column and is counteracting against a rigid structure or other suitable fixed support connected directly to the clamp.

With particular reference to FIG. 8, and with reference to FIG. 9, the lower bolster is shown in the depressed position to separate the mold halves, as shown in FIG. There is. At each corner of the press is located an ejection actuator 95, these actuators being external to the individual columns 17. The extraction actuator includes an outer housing 96 defining a cylinder chamber therein;
A piston assembly 97 is mounted within the chamber, with a working end 99 of the piston assembly extending outwardly from the cylinder chamber. Piston assembly 97
The end 99 of is located in contact with the reaction frame member 100. It is attached to each corner of the press of the frame member 100. As best seen in FIG. 2, each frame member is clamped to an individual post 17, with vertical legs 101 attached to horizontal or frame members 100 to transfer loads to base 16. There is almost no rebound. Frame member 100
and the dimensions of leg 101 are selected to maintain strain at the desired level.

Each take-out actuator 95 is actuated at a particular corner of the press by a common servo valve with the corresponding main forming hydraulic actuator 75. In other words, these two cylinder devices (actuators) work together like one double-acting cylinder, and when the actuator 75 is pressurized, the actuator 95 will actuate the corresponding actuator 75 at each corner of the press. Connected to the outlet via the same servo valve.
Similarly, when actuator 95 is pressurized, actuator 75 in the same corner is connected to the outlet and pulled back.

In another embodiment, the frame member 100 may be replaced by a mechanical stop member 105 as shown.
may be provided in alignment with appropriate pads 106 on the sides of plate 35 near the outer corners. In this case, the extraction force is provided directly between the lower platen assembly and the upper plate. Stop member 105 is a mechanical stop for the upper crosshead. Corresponding extractor actuator 9 at each corner
There are four stop members 105, one on each. The mechanical stop member 105 is, for example, composed of parts of various lengths of the stop member, and the lengths are adjusted so that the desired length can be obtained by combining these parts in various ways depending on the mold height. Adjustment may be possible.

Actuator 95 is suitably guided for limited vertical movement relative to frame member 100. The internal piston has a stop that prevents the rod from exiting the housing. Although the guides are not shown in detail, they are suitably shaped to allow vertical movement of the housing 96 without displacement.

Each actuator is joined to a bolster guide block 107 in order to transmit the separation force from the ejection actuator 95 to the bolster or platen 72 and to simultaneously allow the platen to sway horizontally to change the molded article. connected to this. Guide blocks 107 are shown in plan view in FIG. 9, with each block located adjacent to each post 17. The guide block 107 is arranged in the Y-axis direction (arrow Y in Fig. 9).
relatively short in the direction of ). Each guide block 107 has a side rail 108 on its inner side, which side rail has an upwardly bent lip 10.
It has 8A. The rail 108 fits within a longitudinal groove 110 formed along the side of the platen 72, which groove 110 extends in the front-to-back Y-axis direction the entire length of the platen. As shown, the groove 110 has a surface formed by a locking lip 112 that has a surface that matches the lip 108A to engage the rail 108 for support purposes.
Additionally, the bottom corner 107A of block 107 joins the side of the platen.

The block 107 forming the extraction block is inserted into the housing 9 of the actuator 95 in a suitable manner.
6. For example, these two parts 107, 96 may be secured to each other with cap screws, or these parts 107, 96 may be formed integrally.

When the actuator 95 is actuated, pressure is released from the cavity 79 of the actuator 75 and pressurized oil is supplied into the inner housing 96. When separating the mold, a total of four servo valves, one for each take-out actuator 95, are activated to connect the cavity 79 of the corresponding actuator 75 to the outlet, and supply pressurized fluid to the internal chamber of the housing 96. , thereby pushing housing 96 downward. The reason is that the piston 97 acts on the frame member 100 and the stop 1
05, 106 to the upper platen or plate 35. This forces guide block 107 downwardly, ensuring that the guide block and platen 72 engagement surfaces push platen 72 downwardly at all four corners, thereby pulling actuator 75 back and separating the two mold halves. Separate the molds.

As discussed below, control of the mold operation is provided by a program controller, and displacement transducers are used for feedback for the servo-controlled actuators. When the crosshead assembly and upper platen assembly are retracted, the four displacement transducers 140 located between platen 72 and base member 16
provides feedback control for platen position as adjusted by actuators 75, 96, each acting in opposite directions. There are at least three such transducers 140, but in the illustrated version four transducers are provided to provide information about the horizontal orientation and vertical height of the platen.

The final feedback for the mold controller is provided by four displacement transducers (LVDTs) 120 affixed to the lower mold half 31 at each of the four corners of the mold. Transducer 120 has a spring loaded end 121 positioned to engage a small lug 122 attached to upper mold half 30. When the transducer 120 latches the crosshead in its lowered position,
switched to the control circuit and transducer 140
is used when raising the crosshead.

When the mold half is pulled back as shown so that the heel block 90 is no longer retained within the guide 91, the platen 72 may become roughly misaligned.

Therefore, pull back (lower) the lower platen.
It is sometimes desirable to provide a mechanical positioner for the lower platen. To limit the movement of lower platen 72 and support plate 81 in this manner, a plurality of hydraulic actuators 115 are provided. These actuators 115 have a cylinder and a piston connected to a pin member 116. The pin member has a narrow end 116A and a tapered shoulder connecting the pin end to the pin body. Pin member 1
The 16 pin bodies fit freely into a short sleeve 117 fixed to the bottom of the plate 81. Actuators 115 are located between actuators 75, so that these actuators 115 are located at four locations approximately halfway along and adjacent each edge of plate 81.

Pin member 116 further includes a flange 118;
The flange is dimensioned so that it engages and supports sleeve 117, plate 81, and platen 72 when platen 72 has been retracted to the position of FIG. The pin member 116 forms part of the piston rod, and the internal piston is connected to the actuator housing 119.
The housing defines an internal chamber for pressurized fluid supplied under pressure by suitable valves, and the piston prevents movement of the platen beyond the position shown in FIG. Forms a fixed lower stop for use. These stop actuators 115 resist downward movement against the force exerted by the eject actuators. In other words, unless pressurized fluid is released from housing 119, lower platen 72 cannot be retracted beyond the position substantially shown in FIG.

The pin member 116, particularly the cylindrical pin body shown, securely positions the support plate 81 and the actuator relative to the hydrostatic support, and the slot 110
The lower bolster 72 and lower mold half 31 remain properly positioned during the retraction of the upper mold half 30 and crosshead 36 even though the upper mold half 30 and crosshead 36 have a certain clearance with respect to the rail 108. .

Therefore, the rigid platen 72 supports the static pressure support plate 8
1 to the platen 72. Additionally, the ejection actuator 95 provides a small load path between the upper mold half 30 through the rigid crosshead, vertical post 17, and frame member 100, thereby allowing the mold half to be removed with little or no bounce. Separate. The use of single acting actuators 75, 95 each controlled by one servo valve in the same corner simplifies operation and reduces cost.

The platen 72 forms a rolling bolster that can be rolled to support the rails to replace mold halves or repair the bolster or mold as needed. .

The base member 16 shown in FIGS. 8 and 2 supports a pair of spaced parallel tracks 125 which are positioned externally of the actuator 75 and extend forwardly from the press the desired amount. As shown, platen 72 has wheel housings 126 mounted on its front and rear sides, with wheels 127 shown directly above track 125. At the front end, the wheel is mounted on a crossshaft 128 which is mounted within the housing via suitable bearings and which extends laterally across between the two housings 126. The cross shaft 128 is connected to the hydraulic motor 1 through gear and chain drive means.
30 in the usual manner. Platen 7
The two front wheels 127 are selectively driven by operating appropriate valves to energize the motor 130.

The wheel housing 126 on the rear side of the platen 72 is simply a wheel housing for an idler wheel mounted on a shaft rotatably mounted to the wheel housing.

In the normal rest position of platen 72 and support plate 81, wheel 127 is spaced from the upper surface of track 125, as shown in FIG. However, when it is desired to remove platen 72, fluid pressure within housing 119 of actuator 115 is released, which causes piston and attached pin 116 to be pulled back within the housing, causing wheel 127 to contact track 125. Collar 11 when actuator 75 is compressed to
8 and the platen as well.
The weight of platen 72 causes the platen to lower and then block 107 to move downward as well.

1 of each column just below each block 107.
The collar 135 attached to column 7 is a split collar that can be clamped around each post 17 and has outwardly extending ears (8th and 9th) of appropriate length.
Figure). When clamped together,
The ears form a sloped surface 136 (FIG. 8). The sloped surface is positioned to engage the lower surface of each block 107, causing the block to tilt as the sloped surface moves downwardly. Such tilting causes the rail 108 to rise slightly within the groove 110, thereby causing the contact surfaces 111,
107A, 108A, and 112 are released. Block 107 rests on top surface 136 and platen 72 can be released from rail 108 and moved along track 125. Motor 1
0 allows the platen and mold half 31 attached thereto to be moved into position for mold repair or replacement.

Support plate 81 has sufficient weight to pull piston 77 back and provide clearance between the upper surface of this plate and the lower surface of platen 72, so that
The extremely narrow pin 82 separates from the underside of the platen when the platen rocks. The plate 81 remains in place so that the hydrostatic support formed is not damaged and in particular the seal 83 is not subject to frictional forces and does not allow leakage.

When the platen 72 is released, the platen simply swings back to the position where the rail 108 enters the groove 110. Locating pin member 116 is actuated by supplying pressurized fluid to housing 119 to lift plate 81. These pin members and corresponding grooves 82 interengage to properly position platen 72.

When the mold halves are moved together from the position shown in FIG.
Align freely when entering. Therefore, some floating in the X and Y directions is possible;
Therefore, although the pin member 116 initially aligns the mold, the heel block ultimately aligns the mold.

In the servo valve controllers for actuators 75, 95, program controller 67 provides the press for press operation, timing the movement of the crosshead and the clamp, and actuation of actuator 75 to bring the mold halves closer together. Control. A signal from the program controller to lock the clamp cylinder 54 with the crosshead at the proper position sensed by the LVDT 27 on the actuator 22 is provided to a degree of freedom controller 150. Degree of freedom controller 150
is the lower platen 72 with respect to the upper mold half.
This is a controller that maintains the mold in the proper direction and controls the mold closing movement. The controller 150 executes a program that can be generated in a known manner for servo control and controls sensor 1 until the crosshead is clamped.
Receive feedback from 40 people.

The signal that activates the crosshead clamp also activates an electronic mode control switch that switches feedback to sensor 120. Force feedback from actuators 75 is also used for force control in mold operations, and differential pressure transducer 151 provides such force feedback for each actuator 75 and its corresponding ejection actuator 95.

A separate servo valve 152 is provided for the actuator at each corner of platen 72, so there are four servo valves 152, each receiving a control signal from controller 150.

Fluid for servo valve control flows from the pressure source to the outlet in the usual manner. The signal to servo valve 152 is such that platen 72 is not subjected to forces that would disrupt its parallel relationship to upper mold half 30.
It comes from a position to determine and sense the proper displacement of each actuator 75. This control is therefore related to the multi-axis control system disclosed in US Pat. No. 3,800,588. Displacement feedback control from sensor 140 of the LVDT is performed by displacement transducer 12.
The electronic switch receives a feedback signal from transducer 120 when the clamp clamps the crosshead assembly in a mold position such that mold halves 30, 31 are in close proximity. Switch the controller to automatically sense the

As previously mentioned, heel block 90 provides control for yam, X-axis movement, and Y-axis movement when the mold is closed. This provides control or restraint in three degrees of freedom. Platen 7
Actuator 75 is precisely controlled to control the pitch, yaw, and vertical motion of mold 2 to ensure parallelism of the mold halves.

At least three actuators and three displacement transducers must be provided between the base and the platen to maintain the mold halves parallel. Examples of application in the general case are shown in FIGS. 11 and 12, which schematically illustrate the application of degree of freedom control in the present invention. FIG. 11 schematically shows the platen 72, for example, the parallelism with respect to the upper mold half in pitching as indicated by the arrow "pitch" about axis 155 (the same axis in FIG. 8 that controls the pitch). is maintained and sway about axis 156 is also controlled. In the general case, in order to maintain and control them properly, actuators A ₁ and A ₂ of the same size are placed on either side of the axis 156 and equidistant from this axis, and two of these actuators are Third actuator A ₃ with double area
is provided on shaft 156 at the other end of the platen.
Control of the sway about axis 156 is therefore determined by the displacement of actuators A ₁ , A ₂ with respect to each other. Actuator A ₃ is located the same distance apart from actuators A ₁ and A ₂ with respect to axis 155, and the relative vertical position of actuator A ₃ with respect to actuators A ₁ and A ₂ determines the control position with respect to pitch. The displacement is sensed by displacement sensors X ₁ , X ₂ , X ₃ , which in this case correspond to sensor 120 . (Corresponding to these sensors 140 when the sensors 140 are in the control state.) The displacement signal is transmitted to each actuator A ₁ ,
Corresponds to the vertical position of A ₂ or A ₃ . Additionally, differential pressure transducers are used to determine the force exerted by each actuator, and these transducers are designated F ₁ , F ₂ , and F ₃ . These force transducers can also be used for force balance control as disclosed in US Pat. No. 3,800,588.

Transducers X ₁ , X ₂ are located on either side of axis 156 an equal distance from this axis, this distance being equal to the distance of displacement transducer X ₃ from axis 155 .

The program controller shown in FIG. 12 generates command signals 160 (FIG. 10) for mold control. This command signal is provided to a total meter 161 which forms part of the multi-axis controller 150.

Inputs from displacement transducers X ₁ , X ₂ , X ₃
(Fig. 12) is the averager 16 in displacement control.
2 and sent to total meter 161 as an average displacement signal.

For _the force control shown _in FIG _.
The average force signal from the total meter 1 along line 164
61. An average displacement signal or an average force signal is provided to a total meter 161;
The summed signal is an error signal which, after passing through a suitable amplifier 165 and through line 166, provides the main error signal control for the servo valve.

A compensation signal is required to ensure that the mold halves are held parallel during rapid actuation, and pitch compensation can be achieved by utilizing the displacement signal from a displacement transducer and by using a suitable splitting amplifier. Or by appropriately weighting these signals in the signal conditioning device 170.
The signals from displacement transducers X ₁ and X ₂ are divided into four parts, and the signal from displacement transducer X ₃ is divided into four parts. This is because transducer X ₃ is the single transducer at a particular end of platen 72. If four displacement transducers are used as shown in FIG. 8, a fourth signal X ₄ ' exists,
Each of these signals is divided into four by the signal conditioning device 170. Transducer X ₁ ,
The signal from X ₂ is sent to the positive input of summing amplifier 171 and the signal from transducer X ₃ is sent to the negative input of said amplifier 171, whereby these signals are averaged by summing amplifier 172. Ru. The averaged signal is summed with the signal from line 173 representing the desired amount of pitch signal and amplified in amplifier 174. This signal is then sent along line 175 to the control amplifier for each servo valve in the circuit.

Compensation for sway in this particular case is accomplished by splitting the signals from displacement transducers X ₁ , X ₂ (which control sway about axis 156) into two; line 18
This signal above 0 is the average roll signal and is sent to a summator 181 where it is summed with the signal from line 182 which allows for the selection of a certain roll. 182 for parallel operations
The upper signal is zero. This signal is sent to the amplifier 183
with a weighting factor at line 18
4 to the valve controller.

In this particular example, each actuator A ₁ ,
A ₂ and A ₃ have separate servo valves controlling them, and the signal from line 166 is sent to a valve amplifier for each actuator. The signal to the valve amplification is at the output of amplifiers 185, 186, 187.
Shown as A ₁ , A ₂ , and A ₃ .

In control, the error signal along line 166 is sent to the positive inputs of respective summing amplifiers 185, 186, 187 for actuator A ₁ , actuator A ₂ and actuator A ₃ . Additionally, the summed signal indicative of pitch error is routed along line 175 to summation amplifier 1.
85, 186 and to the negative input of a totalizing amplifier 187 for actuator _A3 . This can be done, with respect to pitching, by making actuator A ₃ not extend as much as A ₁ , A ₂ during each cycle, or by making actuator A ₃ extend more than A ₁ , A ₂ . , meaning that modifications can be made.

The error signal for lateral sway compensation is on line 184.
This signal is fed along the actuator
It is sent only to summing amplifiers 185 and 186 for A ₁ and A ₂ . The reason is that actuator A ₃ does not control sway. The signal on line 184 is therefore sent to the negative input of amplifier 185 and the positive input of amplifier 186. Of course, this means that the correction for errors in sway is carried out by extending one of the actuators A ₁ or A ₂ with respect to each other.

The signal from amplifier 187 is amplified by a factor of two in amplifier 190. This is because, in the illustrated example, actuator A ₃ has the same capacity as actuators A ₁ and A ₂ . This signal is sent to the servo valve in the usual manner. If there are many (e.g., four) actuators, the sway control is a summation amplifier for the actuators on each side of the shaft 156 at the end of the platen 72 where actuator A ₃ is now located. , and therefore an additional summing amplifier is provided for the additional (eg fourth) servo valve.

If the actuator is located at a different distance from the axis to be controlled, the signals are weighted proportionally to the distance from the axis.

The lower platen of the forming press is therefore hydraulically controlled in three degrees of freedom: vertical, lateral and oscillating, and in three other degrees of freedom (X-axis, Y-axis and oscillating). ) is mechanically controlled by a heel block. Therefore, the platen is precisely controlled to maintain parallelism between the two mold halves as sensed by the displacement transducer.

FIG. 10 is a graph illustrating the control functions of the main operations in the forming press of the present invention as determined by the program controller. One complete cycle of the mold operation is shown in FIG. 10, with time (horizontal axis) increasing to the right. The starting point of the cycle is the leftmost vertical line and the first operation that occurs is curve 141
This curve represents the position of the upper crosshead with respect to time. Curved section 141A shows the crosshead being lowered, and curved section 141B shows the crosshead in the lowered position with the upper mold half properly positioned for mold operation. Indicates the status of the clamp actuator cylinder. The actuation curve 142 of the clamp actuator cylinder is shown in two parts, the lower curved part 142
A indicates that the crosshead is clamped in place. These clamp actuator cylinders are then pressurized. Curved portions 141A, 14
1C is generated electronically by a program signal to servo controller 69 of FIG. The curved portion of the program signal provides smooth acceleration and deceleration of the (often) extremely heavy upper crosshead assembly. This smooth movement is important for reliable operation of the invention.

When the upper crosshead assembly reaches its molded position (opposite the junction of curved sections 141A and 141B), the crosshead clamp is quickly actuated to lock the crosshead in place. As soon as the crosshead is locked, actuator 75 is activated by servo valve 152. The upper part of the timing diagram shown in FIG. 10 shows the mold operation, in detail the lower platen 7.
2 and the movement of the mold half 31. The two curves represent the mold operation. The upper curve at 143 represents mold displacement and the lower curve 144 represents mold force.

Once the actuator 75 begins to move the mold toward its closed position, the movement of the actuator is placed under displacement control as shown by solid line portion 143A. It can be seen that the mold is moved until it is substantially adjacent to the upper mold line, indicated by horizontal line 145. The slight gap shown in the figure is for compressing the filler material within the mold, which consists of mold halves separated by the thickness of the material to be molded.

As soon as the mold closes (point of dashed line 146),
Control of actuator 75 is electronically switched to force control as represented by solid line segment 144A of curve 144. The force is maintained (line 144B) for the time necessary to cure the article being formed (by applying heat).

If the mold must be opened to inject the coating agent for coloring or other purposes, the force represented by the displacement control U-shaped solid line portion 144C decreases rapidly when the mold is opened. Then, immediately after injection of the coating material has occurred, the mold displacement control moves the mold to its closed position (the upper right portion of the solid line section 143B) and the dotted line 1
Close again as shown at 43C. Meanwhile, a molding force, indicated by solid line portion 144D, is applied to control pressure on the mold until sufficient curing time has expired (point indicated by vertical line 147).

Displacement control is then switched back to the controller for actuating the ejection actuator 95 (and hydraulic actuator 75) to open the mold, and this displacement control curve is represented by line segment 143D indicating mold opening. The force is line segment 1
44E.

When the mold begins to open and separate, the line portion 14
The crosshead clamp is released, as shown at 2A, and the release actuator 60 is then pressurized, raising the crosshead to its raised position, as shown at line section 141C. When the crosshead has been pulled back, double-headed arrow 14
The length of time indicated by 8 is used to remove the molded article and fill the mold with new material, and the cycle is repeated.

The controller thus provides signals for actuating the crosshead control cylinder, clamp cylinder, forming cylinder, and ejection cylinder.
The clamp cylinders are not servo controlled and receive sufficient hydraulic pressure when valve 69A is actuated to actuate these cylinders (and release actuator 60) to securely clamp the crosshead in place.

In FIG. 10, switching between force control and displacement control (curves 143, 144) of the mold is performed electronically in a known manner. Curves 143, 144
The solid line portion shows when the control mold is active, while the dotted line portion shows when the control mode is passive (switched out of the circuit).

A program for operation can be obtained from existing controllers that provide electrical signals to provide the motion and forces shown in FIG.

Although a vertical press was described herein,
If desired, the post 17 may be horizontal and the forming cylinder may be operated with respect to a movable crosshead. The disclosed hydraulic press may be used as an injection molding press, forging press, or other press.

[Brief explanation of the drawing]

FIG. 1 is a front elevational view of a compression molding press embodying the present invention, FIG. 2 is a partially broken side elevational view of the press of FIG. 1, and FIG. 3 is a plan view of the molding press of FIGS. 1 and 2. 4 is a front elevational view of the upper crosshead assembly shown in FIG. 3; FIG. 5 is a graph showing the crosshead of the press apparatus according to the invention and the deflection of a conventional crosshead used in a press; and FIG. The figures are a partially cutaway sectional view showing the inside of a locking cylinder used with the crosshead shown in FIG. 4, FIG. Fig. 8 is a partially cutaway front end view of the lower platen used in the press apparatus of the present invention, Fig. 9 is a partially cutaway top view of the platen shown in Fig. 8, and Fig. 10 is the operation of the forming press elements during the press cycle. A graph illustrating the sequence, Figure 11, schematically depicts the lower platen assembly to illustrate the basic servo control concept for maintaining the lower platen parallel to a reference, such as the upper mold half, during press operation. 12 is a block diagram of a control circuit related to FIG. 10. 15... Frame body, 16... Base member, 17...
Pillar, 20... Upper platen assembly, 22... Actuator, 26... Lower platen assembly, 3
0, 31... Mold half, 36... Crosshead assembly, 46... Clamp, 60... Actuator, 75... Hydraulic actuator, 95...
Actuator for extraction.

Claims (1)

[Claims] 1 It has a frame 15, and the frame 15 is connected to the base member 1.
6 and a crosshead assembly 36 mounted on the frame 15 and spaced apart from the base member 16, the base member 16 supporting the lower platen assembly 26; The crosshead assembly 36 supports the upper mold half 30, the lower platen assembly 26 supports the lower mold half 31, and provides a force for closing the upper and lower mold halves 30, 31. at least one hydraulic actuator 7
5, wherein the hydraulic actuator 75 is connected to the base member 1.
6 and the lower platen assembly 26, the hydraulic actuator 75 has an actuator surface facing the lower platen assembly 26, and a sealing means 83 is mounted on the actuator surface, and the hydraulic actuator 75 has an actuator surface facing the lower platen assembly 26, and a sealing means 83 is mounted on the actuator surface. Means 83 press against the surface of the lower platen assembly 26 to define a chamber between the actuator surface and the surface of the lower platen assembly 26 having a cross-sectional area less than the effective area of the hydraulic actuator 75. A passage 84 is provided between the interior of the hydraulic actuator 75 and the chamber, and the passage supplies pressurized fluid from the interior of the hydraulic actuator 75 into the chamber to connect the lower platen assembly. The lower mold half 31 is configured to statically support the lower mold half 26 so that the lower mold half 31 does not receive side loads during the pressing process. A press device characterized in that it is movable in a plane parallel to the plane of the platen assembly 26. 2. The press apparatus according to claim 1, wherein a plurality of the hydraulic actuators 75 are arranged between the base member 16 and the lower platen assembly 26. 3 has a frame 15, and the frame 15 is connected to the base member 1.
6 and a crosshead assembly 36 mounted on the frame 15 and spaced apart from the base member 16, the base member 16 supporting the lower platen assembly 26; The crosshead assembly 36 supports the upper mold half 30, the lower platen assembly 26 supports the lower mold half 31, and provides a force for closing the upper and lower mold halves 30, 31. at least one hydraulic actuator 7
5, the hydraulic actuator 75 is disposed between the base member 16 and the lower platen assembly 26, the hydraulic actuator 75 having an actuator surface facing the lower platen assembly 26; A sealing means 83 is mounted on the actuator surface, and the sealing means 83 presses against the surface of the lower platen assembly 26 to seal the hydraulic actuator 75 between the actuator surface and the surface of the lower platen assembly 26. A passage 84 is provided between the interior of the hydraulic actuator 75 and the chamber, and the passage 84 defines a chamber having a cross-sectional area smaller than the effective area of the hydraulic actuator 75 . Pressure fluid is supplied into the chamber to provide static pressure support to the lower platen assembly 26, and the static pressure support causes the mold radii 30, 31 to receive side loads during the pressing process. In the press apparatus, the lower mold half 31 is movable in a plane parallel to the plane of the lower platen assembly 26 so that the base member 16 and the lower platen assembly 2
A take-out actuator 95 that applies a releasing force to both mold halves by applying a force between them and the hydraulic actuator 75 is provided in a one-to-one correspondence with the hydraulic actuator 75 to form a pair. Both actuators 75, 95 are connected to a servo valve 152 common to both actuators 75, 98,
The servo valve 152 is characterized in that when the hydraulic actuator 75 is operated, the take-out actuator 95 is not operated, and when the take-out actuator 95 is operated, the hydraulic actuator 75 is not operated. Press equipment. 4. In the press apparatus according to claim 3, a plurality of the hydraulic actuators 75 are arranged between the base member 16 and the lower platen assembly 26, and the take-out actuator 9
A plurality of servo valves 5 are provided in one-to-one correspondence with the hydraulic actuator 75, and the servo valve 152 is connected to the actuators 75 and 95 that form a pair.
A press device that is equipped with multiple units to correspond to the following. 5. In the press device according to claim 4, the movement on the two axes parallel to the dividing plane of the two mold halves 30, 31 and perpendicular to each other is said hydraulic actuator 75 is provided so as to be controlled by the individual operation of said hydraulic actuator 75;
Both mold halves 3 around the axis of the book shaft
A sensing device is provided for sensing relative movements of 0.31, the sensing device outputting a feedback signal representative of the respective position of the sensing device, and the pressing device further outputs a feedback signal of the sensing device. a signal coupling device coupled to a program control signal to provide an independent signal for each of the servo valves, each of the servo valves receiving the feedback signal from each of the sensing devices to control the hydraulic actuator 75; Said press device for correcting the actuation and thereby precisely controlling the position of said mold half about said mutually perpendicular axes.