US3427856A

US3427856A - High speed returning impact forming machine

Info

Publication number: US3427856A
Application number: US621940A
Authority: US
Inventors: Akira Asari
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 1966-03-14
Filing date: 1967-03-09
Publication date: 1969-02-18
Anticipated expiration: 1986-02-18
Also published as: AT269601B; GB1174295A; DE1627430A1; FR1514617A

Description

Feb. 18, 1969 AK|RA s l 3,427,356

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet of 8 (Rom held upwords) m INVENTOR.

Feb. 18, 1969 AKIRA ASARI 3,427,856

. HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 2 of s (Forming) v INVENTOR.

Feb. 18, 1969 AKlRA ASARI 3,

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9,1967 Sheet 3 of (Ram on The way upwards) INVENTOR.

BY ad/ W Feb. 18, 1969 AKIRA ASARI 3,427,355

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 4 of 1 lOdlOb"

/ lOb" 1| miummrm u u v (Rom returned completely) 04010 INVENTOR.

Emma 524 Feb, 18, 1969 AKIRA' ASARI 3, ,35

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 5 of 8 lOc (Crank uppermosr) Y INVENTOR.

Fb. 18, 1969 AKIRA ASARI 3,427,355

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed Harsh 9. 1967 Sheet 6 of (Frame descended completely) INVENTOR.

Feb. 18, 1969 AKIRA ASARI 3,427,356

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 7 of s Cronkfl2) Rum Supporfing (10) LVGlve (7) Movable Frame BYLUMM Feb. 18, 1969 I AKIRA ASARI 3,427,856

HIGH SPEED RETURNING IMPACT FORMING MACHINE Filed March 9, 1967 Sheet 8 of a IOd I Y 1AM United States Patent 3,427,856 HIGH SPEED RETURNING IMPACT FORMING MACHINE Akira Asari, Osaka-shi, Japan, assignor to Kobe Steel Ltd., Fukiai-ku, Kobe, Japan Filed Mar. 9, 1967, Ser. No. 621,940 Claims priority, application Japan, Mar. 14, 1966,

41/ 16,048 US. Cl. 72-450 8 Claims Int. Cl. B21j 9/18, B30b 1/32 ABSTRACT OF THE DISCLOSURE Cross reference to related application Reference is made to US. patent applications of Akira Asari entitled, High Energy Rate Forming Machine, Ser. No. 384,103, filed July 21, 1964, now Patent No. 3,354,693; Method for Operating the Ram in an Impact Processing Machine and a Device for Carrying Out Said Method, Ser. No. 564,681, filed July 12, 1966; and A Knock-Out Device of Impact Forming Machine, Ser. No. 574,033, filed Aug. 22, 1966.

Background of the invention This invention relates to a high speed returning impact forming machine in which gas pressure is utilized as a source of power for driving its ram, and more particularly is directed to an impact forming machine in which a mechanical force is used for returning a ram in high speed and hydraulic pressure stopper means are adopted for returning the ram in safety supporting.

It has been found that an impact forming machine deforms various materials by using the velocity energy by means of a high speed of ram and a very large force can be obtained by this and furthermore, it has the feature of having a very high fabrication speed.

Machine for using gas pressure is preferred t machine for utilizing a mechanical force in order to supply high speed energy to a ram so that the ram is forced in extremely high speed. For driving the ram by using gas pressure, there are various ways for using the gas pressure for driving the ram, but the common manner is such that the ram is driven downwards in a very high speed by receiving gas pressure on the upper surface of the ram, whereby the desired forming work is done in a metal mould provided on the machine.

In such an operation, since the impact force of the ram is great amount, which effects a great deal of shock and vibration on the ground, the moving frame of this machine for operating the ram is supported through a cushion such as an air spring so that it is laterally movable up and down. However, if the frame is supported so as to move laterally, when the ram is returned back upwards by means of a jacking mechanism secured to the fixed frame after its descent has completed to operate its impact forming, the movable frame tends to move upwards 3,427,856 Patented Feb. 18, 1969 together with the ram. Accordingly, the impact formed product in the metal mould is delayed to separate therefrom, causing bad effect thereto. Furthermore, the relative motion between the ram and the movable frame is effected to be inaccurate, thereby becoming very diflicult to set the operating time of the valve for controlling the operation of the ram so as to communicate between the high pressure chamber and the upper portion of the cylinder for receiving the plunger integral to the ram.

Further, when the ram is in a state that it initiates to return to its uppermost position after impact forming operation, since the high pressure in the gas pressure member operates so that it pushes upwards the movable frame, if there is no stopping means for stopping the movable frame, the frame moves upwards together with the ram so that the metal moulds may not separate each other. If the stopper means secured to the fixed frame stop from the first the upward movement of the movable frame even if the upward motion of the movable frame is adapted to be prevented by a part or stopper means of the fixed frame, the reaction of the movable frame is impossible to be effected in the impact forming operation. Or, if the space between the movable frame and the stopper means secured to the fixed frame is predetermined to be provided, the reaction of the movable frame is allowed, however whilst the stroke from that the ram initiates to return upwards to its uppermost position after its impact forming operation to that the movable frame raises upwards so as to contact with the stopper means secured to the fixed frame is done, the movable frame moves further upwards together with the ram, between which the metal mould is held in contact each other.

Assuming that the valve for communicating between the gas pressure chamber and the upper portion of the cylinder for receiving the plunger integral to the ram is open or is not closed completely immediately after the ram reaches its initial uppermost position so as to lower the supporting member, the high pressure of the chamber flown back through the conduits and the valve effects to actuate upon the upper surface of the plunger so that it initiates to descend the ram accidentally causing its dangerous operation. However, when the supporting member of the ram reciprocates up and down by means of a mechanical force such as the crank, it moves downwards or in such a direction that it separates from the ram immediately after it reaches its initial uppermost positions so that it removes the supporting operation of the ram. Accordingly, the valve must be closed immediately after the supporting member reaches its uppermost position.

If the valve closes before the ram reaches its uppermost position, the gas enclosed in the cylinder cannot return through the conduits and the valve to the chamber. Furthermore, the plunger of the ram is not yet reached to its uppermost position or its inner uppermost position, accordingly the compression occurs in the cylinder by the plunger. Also, if the valve closes in some delay after the ram arrives at its uppermost position, the gas flown back through the conduits and the valve initiate to operate accidentally the ram, since the supporting member initiates to descend before the valve closes.

Summary of the inventi n This invention eliminates the above mentioned disadvantages of the conventional impact forming machine and provides a novel high speed returning impact forming machine in which an impact forming operation is shortened by using the mechanism for converting rotational motion to a reciprocating movement upon returning the ram to the initial uppermost position after it has performed the impact forming operation, and also when the ram returns upwards to its initial uppermost position the metal moulds separate immediately each other by adopting the hydraulic pressure stopper means disposed above the movable frame and secured to the fixed frame.

The principle of the present invention, which will be hereinafter described, is that in the high speed returning impact forming machine provided with a movable frame supported by means of cushion a returning motion of the movable frame is restricted. That is, the reaction of the movable frame is allowed in its impact forming opera tion, however when the ram initiates to return upwards to its uppermost position immediately after its impact forming operation, the movable frame is prevented to raise upwards together with the ram, and only ram is permitted to return upwards to its uppermost position so as to effect to separate the impact formed product from the metal mould immediately. Further, in the impact forming machine in which after its impact forming operation the ram is returned upwards to its initial uppermost position by means of mechanical jacking mechanism such as a crank mechanism, the ram is returned upwards integrally with the movable frame in some stroke even after it reaches its uppermost position relative to the movable frame, thereby the time for enabling to control the valve for communicating the high pressure from the gas pressure chamber to the upper portion of the cylinder for operating the ram, is effected to lengthen. More particularly, the ram operated by the high pressure in the chamber is supported or held by the movable frame supported by means of the cushion, and in order to return the ram to its initial uppermost position the jacking mechanism secured to the fixed frame is utilized so as to enable lateral movement up and down relative to the movable frame or the stopper means are provided. This stopper means is, for example, comprised of a piston and cylinder in combination. It is adapted to drive the piston by means of hydraulic pressure. The stopper means allow its reaction of the movable frame in its impact forming operation to operate, however in the returning stroke of the ram after its impact forming operation it does not permit its returning movement of the movable frame together with the upward movement of the ram. On the other hand, the stopper means have a cushioning function against the jacking mechanism in the returning stroke to the uppermost position of the jacking mechanism after the ram returned to the uppermost position in the movable frame. And for the cushioning of the stopper means against the jacking mechanism another cushioning means or hydraulic pressure means may be used.

One advantage of this invention is referred to the stopper means which is disposed fixedly to the upper portion of the fixed frame and which comprises hydraulic pressure cylinder disposed fixedly downwards to the frame, stopper pistons being inserted to the cylinder, and rods adapted to be integral to the piston, the rods being projected downwards and disposed opposite to the upper surface of the movable frame, thereby enabling to stop the movable frame moving upwards. It is operated so that when the ram returns upwards metal moulds separate immediately each other so as to pick up easily the impact formed products. The piston of the stopper means is adapted to be capable of laterally moving upwards and downwards by applying hydraulic pressure from the upper or lower portion thereof. And the stopper means are so disposed that the distance between the lowermost portion of the rods and the uppermost of the movable frame balanced with the cushion is larger than the bounded height of the movable frame from the normal level caused by the reaction of the ram descended. Thus, it provides the cushioning function with its initial stopping operation.

It is another advantage of this invention that the stopper piston of the stopper means is adapted to be disposed at its lowermost position immediately before the supporting member initiates to contact the head of the stem on the way moving from its lowermost position, and it is disposed so that when the plunger of the ram reaches its uppermost position in the cylinder the crank enable to raise further integrally with the supporting member together with the ram on opposing to the hydraulic pressure in upper portion of the stopper means in its rested stroke. Thus, only the ram returns upwards to its initial uppermost position and the impact formed products are separated from the metal mould.

Yet another advantage of this invention is seen in that for a little while from the middle until the crank reaches its uppermost position, the crank is allowed to raise further in a state that the ram holds in its uppermost position. Therebetween, the crank initiates its down stroke. Thus, even if the ram is not held in its uppermost position, the high pressure gas in the chamber is not permitted to flow back through the conduits and the valve so as to effect upon the upper surface of the plunger so that the ram may not be operated accidentally to descend downwards to operate its impact forming.

=Therefore, one object of this invention is to provide a high speed returning impact forming machine in which when the ram returns to its uppermost position it is safely and positively supported.

Another object of this invention is to provide a high speed returning impact forming machine in which metal moulds separate easily and immediately each other when the ram returns upwards to its uppermost position.

A still further object of this invention is to provide a high speed returning impact forming machine in which in the returning stroke of the ram the movable frame may not be permitted to move upwards with the upwards movement of the ram.

Still another object of this invention is to provide a high speed returning impact forming machine in which the reaction of the movable frame when the ram operates its impact forming is allowed and further when it returns only the frame is restricted to raise.

Still another object is to provide a high speed returning impact forming machine which has a cushioning function together with stopping operation of the movable frame when the ram returns upwards.

Still another object is to provide a high speed returning impact forming machine in which a great impact force by the ram is cushioned.

A further object of this invention is to provide a high speed returning impact forming machine in which the valve for communicating the high pressure in the gas pressure chamber to the upper portion of the cylinder for operating the ram, is controlled smoothly to open or close.

Still another object of this invention is to provide a high speed returning impact forming machine in which drawback in the cylinder is removed.

This invention provides a high speed returning impact forming machine employing gas pressure means in which machine a mechanism for converting the rotary motion to linear reciprocating movement is provided, by which mechanism the linear motion converted from the rotating movement is adapted to correspond to the driving direction of the ram, and the reciprocating motion thereof is transmitted to the returning member or the ram supporting member, thereby the ram is returned to its initial uppermost position through the member to which the extended portion upwards integrally from the top of the ram or a stem is hung. Thus, the impact forming machine in accordance with this invention is provided such that the ram is returned to its initial uppermost position by means of linear motion of the aforementioned mechanism such as a crank mechanism in high velocity after the impact forming operation has done, accordingly the impact forming cycle is shortened in great amount. In addition, the cycle is made continuous operation and the efficiency of the operation is extremely improved in impact formation of the machine in accordance with this invention.

Furthermore, this invention provides a novel and improved high speed returning impact forming machine wherein part of the mechanical force, by which the ram is returned to its initial uppermost position by means such as the crank mechanism, is used in the operation for opening or closing a control valve of a ram driving gas pressure, thereby enabling the coo-peration with the actuation of the ram and the further rationalization of the operational program in the impact forming machine according to this invention.

In order to hold the ram returned to its initial uppermost position safe because of its importance so as to avoid the accidental operation of the ram in improper time when the ram is raised to its uppermost level caused by the adoption of the mechanical force to return the ram to its initial uppermost position, this invention also provides a high speed returning impact forming machine in which hydraulic pressure means are provided and which comprises a piston provided on the top of means for driving the ram supporting member, a cylinder for receiving the piston provided on the lowermost portion of the member, communications bored longitudinally along with the member, and conduits for connecting the ends of the communication and source of the hydraulic pressure, and is disposed between the top of the crank mechanism and the lowermost portion of the supporting member, thereby operating so that the crank mechanism for driving the supporting member move further upwards to the top during a little while after the ram integral to the supporting member has reached. Thus, this invention eliminates the drawback in the cylinder received by the plunger integral to the ram and the accidental descent of the ram.

Further, this invention also provides the impact forming machine in which the reaction of the movable frame is allowed in its forming operation, but when the ram initiates to return upwards to its uppermost position immediately after its impact forming operation, the movable frame is prevented to raise upwards together with the ram, and only ram is permitted to returnupwards to its uppermost position so as to effect to separate the impact forming machine in which after its impact forming operation the ram is returned upwards to its initial uppermost position by means of mechanical jacking mechanism such as a crank mechanism, the ram is returned upwards integrally with the movable frame, thereby the time for enabling to control the valve for communicating the high pressure from the gas pressure chamber to the upper portion of the cylinder for operating the ram, is effected to lengthen.

This invention provides also a high speed returning impact forming machine in which the ram operated by the high pressure in the chamber is supported or held by the movable frame supported by means of the cushion, and in order to return the ram to its initial uppermost position the jacking mechanism secured to the fixed frame is utilized so as to enable lateral movement upwards and downwards relative to the movable frame or the stopper means are provided. These stopper means are comprised of a piston and cylinder in combination, which means are adapted to drive the piston by means of hydraulic pressure, and allow its reaction of the movable frame in its impact forming operation to operate, but in the returning stroke of the ram after its impact forming operation it does not permit its returning movement of the movable frame together with the upward movement of the ram.

Other objects and advantages of this invention will further become apparent hereinafter, and from the drawings.

Brief description of the drawings FIGS. 1 through 6 are sectional side elevations of a high speed returning impact forming machine constructed in accordance with a preferred embodiment of the present invention showing in its operational order;

FIG. 7 is an explanatory graph of operational curve of respective parts in impact forming operation; and

FIG. 8 is a sectional side elevation of another embodiment of a high speed returning impact forming machine of this invention.

Description of the preferred embodiment Although specific forms of the invention have been selected for illustration in the drawings, and the following description is drawn in specific terms for the purpose of describing those forms of the invention, this description is not intended to limit the scope of the invention, which is defined in the claims.

Referring now to the drawings, and particularly to FIGS. 1, 2, 3, 4, 5 and 6, a high speed returning impact forming machine comprises a gas pressure chamber 1 containing high pressure gas charged therein, a ram 2 adapted to pass into the interior of the chamber from the bottom wall thereof, a plunger 3 formed on the uppermost end of the ram 2, a cylinder 4 constructed inside the uppermost wall of the chamber 1 so as to receive the plunger 3, conduits 5 and 6 connected between the upper portion of the chamber 1 and the uppermost portion of the cylinder 4 through a valve 7, a rod 8 projecting vertically upwards from the plunger 3 integrally for supporting the ram 2 by hanging a head 9 formed on the top of the rod 8 through a ram supporting member or moving frame 10 so that the rod 8 communicates through an opening 11 for the head 9 so as to be through above the opening 11, the diameter of the head 9 being larger than that of the opening 11, so as to hang the ram 2 integral with the rod 8, movable frame 10a disposed inside guides 10b of fixed frame 10c, said movable frame being adapted to be laterally movable up and down, and being supported by means of cushion 26 disposed under the lowermost of the movable frame and station of this machine. A crank shaft 12 driven by any conventional source of power (not shown), in the embodiment shown in the drawings two crank shafts being disposed so as to drive the ram supporting member 10 from opposite sides, respectively, two connecting rods 13 connected to the crank shaft 12 at respective ends, thereby when the crank shafts are driven the supporting member 10 moves reciprocally upwards and downwards in response to the rotation of the shaft 12 through the connecting rods 13.

In the drawings, in operation of the impact forming machine, since high pressure gas is enclosed inside the gas pressure chamber 1, the plunger 3 is pressed to the uppermost position of the cylinder 4 when the ram 2 is disposed in the upper position so that the ram 2 is held in upper lever by the effect of the pressure in the chamber 1 to the lower surface thereof. Furthermore, when the ram 2 is initiated to lower downwards by flowing the high pressure gas in the chamber 1

throughthe conduits

5 and 6, and the valve 7 into the upper portion of the cylinder 4 so that the upper surface of the plunger 3 falls downwards lower than the lower surface of the cylinder 4, the pressure of the chamber 1 effects immediately upon the upper surface of the plunger 3 so as to lower the ram 2 in very high speed, thereby forming the material in the mould in the impact forming machine. And, the ram 2 once lowered as mentioned above is forced so as to be lifted back upwards when the crank 12 is revolved further so as to raise the ram 2 through the connecting rods 13 and the rod 8 integral to the head 9 thereupon, the ram supporting member 10, so that the supporting member 10 hangs up the head 9 through the opening 11 of the supporting member 10. Since the compression is produced in the cylinder 4 when the ram 2 is returned upwards, immediately after the plunger 3 is inserted into the cylinder 4, this compressed gas must be flown back to the pressure chamber 1 through the

conduits

6 and 5 and the valve 7. The supporting member is so constructed that from opposite

ends supporting rods

10d, 10d is projecting downwards, respectively, which rods are disposed laterally slidably inside guides 10b, 10b of fixed frame 100 and connected to the top of the connecting rods 13 of the crank 12 so as to be driven. The rotating shaft 27 for driving the crank 12 is connected through sets of

gears

23 and 24, rotating shaft 22, cam 20 and valve stem 21 to the valve 7.

At the upper portion of the fixed frame 10b over the movable frame 10a is laterally secured hydraulic pressure stopper means 15, 15 which comprise hydraulic pressure cylinder 16 disposed fixedly downwards to the upper portion of the fixed frame 10b, stopper piston 17 being inserted to the cylinder, and rod 14 adapted to be integral to the piston 17, the rods being projected downwards and disposed opposite to the upper surface of the movable frame 10a, thereby enabling to stop the movable frame 10a moving upwards. The pistons 17 of the stopper means are adapted to be able to laterally move upwards and downwards by applying hydraulic pressure from the upper or lower portion of the cylinder. The lateral stroke L of the piston 17 is required, as will be described hereinafter, so that the piston enables to press down the movable frame 10a sufficiently in order that the movable frame disposed at its normal level may not move upwards. This combination of the stopper piston 17 and the hydraulic pressure cylinder 16 forms stopper mechanism together with cushioning function.

In FIG. 1 illustrates the state immediately before the impact forming machine initiate to form its operation in which state a movable frame 10a is balanced at the normal position (designated by line A in FIG. 7) between the weight itself and a cushion 26. The ram 2 is held at the uppermost position by the high pressure of the gas in the chamber 1 which pressure is acted on the lower surface of the plunger 3 (ram kept upwards in FIG. 1, and designated by numeral I in FIG. 7). At this time, the stopper piston 17 is disposed at its uppermost position (line B in FIG. 7) and is held by the hydraulic pressure by the crank 12 the ram supporting member 10 is just on the way to fall downwards. The valve 7 is, of course, close (illustrated by line C in FIG. 7). At that time, a cam 20 is adapted to push upwards a valve stem 21 of the valve 7 so as to open the valve 7 (designated by numeral in position in FIG. 7), thereby the high pressure gas in the chamber 1 is introduced to the upper portion of the cylinder 4 through the

conduits

5 and 6 and the valve 7, which initiate to start to lower the ram 2 downwards. When the upper surface of the plunger 3 falls to separate from the lower surface of the cylinder 4, the high pressure gas immediately operate to push on the upper surface of the plunger 3 so that the ram 2 is forced to fall downwards in very high speed to operate its impact forming (forming in FIG. 2, and designated by numeral II in FIG. 7). At this time, simultaneously with the fall of the ram 2 by its reaction the movable frame 10a moves upwards in height H from the normal position or level A, thereafter immediately descends, and further falls down proper amount from the normal level A. Thereafter, it returns immediately to the normal level A. This height H is sufficiently smaller than space L between the upper surface of the movable frame 10a disposed at its normal position A and the lowermost end of the rod 14 of the stopper piston 17, accordingly the movable frame 10a does not contact the rod 14. This bound of the movable frame 10a is effected because it is supported by the cushion 26 in a movable state.

While the above mentioned operation is held, since the crank 12 further rotate from its lowermost dead point to initiate to raise, the stopper piston 17 is pressed downwards to its lowermost point (that is, stroke L) by the hydraulic pressure immediately before the supporting member 10 contacts with the head 9 of the stem 8 (illustrated by numeral II in FIG. 7). Thus provided, even if the crank 12 raise the ram 2 integral to the stem 8 through the supporting member 10 immediately thereafter, the movable frame 10a does not move upward together with the ram 2 by pressing through the aforementioned stopper piston rod 14, causing only the ram 2 raise so that the metal moulds immediately separate and the impact formed products is at once able to be removed from the mould by an ejecting operation.

FIG. 3 shows the state that the ram initiates to return upwards to its initial uppermost position (designated by numeral III in FIG. 7). Since the high pressure gas in the chamber 1 is operated to the ram 2 so as to raise the movable frame 10a when the ram 2 is returned by the crank mechanism to its initial uppermost position, if there is no means such as stopper means 15, the movable frame 10a move upwards together with the ram 2, causing the metal moulds 28 does not separate each other.

If the stopper means 15 secured to the fixed frame 10c stop from the first the upward movement of the movable frame 10a even if the upward motion of the movable frame 10a is adapted to be prevented by a part or stopper means 15 of the fixed frame 100, reaction of the movable frame 10a is impossible to be effected in the impact forming operation. Or, if the space between the movable frame 10a and the stopper means 15 secured to the fixed frame is predetermined to be provided, the reaction of the movable frame 10a is allowed, however, whilst the stroke from that the ram 2 initiates to return upwards to its uppermost position after its impact forming operation to that the movable frame 10a raises upwards to contact with the stopper means secured to the fixed frame 100 is done, the movable frame 10a moves further upwards together with the ram 2, between which the metal mould 28 is held in contact each other.

Therefore, the stopper piston 17 in the stopper means 15 in accordance with this invention must be laterally movable. That is, the stopper piston 17 allows the movable frame 10a to operate its reaction upon its impact forming operation, and it must be laterally movable up and down in order that it stops the upward movement of the movable frame 10a together with the ram when the ram 2 returns upwards to its initial uppermost position after its impact forming operation.

While the ram 2 returns, the valve 7 maintains to open, thereby the high pressure gas enclosed in the cylinder 4 of the pressure chamber '1 is flown back through the

conduits

5 and 6 and the valve 7 to the chamber 1. When the plunger 3 of the ram 2 is inserted fully upwards inside the cylinder 4 so as to complete to return the ram 2,

the ram 2 is in a state that it is integral to the movable' frame 10a (ram returned completely in FIG. 3, and desnated by numeral III). At this point, since the crank 12 is not yet reached to the initial uppermost position and further the ram 2 continue to raise, from this point the ram 2 and the movable frame 10a integrally move upwards opposite against the hydraulic pressure of the stopper piston 17 further in the rested stroke D. Therebetween, the cam 20 is adapted to close so as to shut off the

conduits

5 and 6 in order to keep its safe state (crank in its upper-most position in FIG. 4, and illustrated by numeral IV in FIG. 6).

Thus, during the stroke D until the crank 12 reaches its uppermost position, the crank 12 are allowed to raise further in a state that the ram 2 holds in its uppermost position. Therebetween, the closure operation of the valve 7 is positively done. Thereafter, the cranks 12 initiate its down stroke. Thus, even if the ram 2 is not held in its uppermost position, the high pressure gas in the chamber 1 is not permitted to flow back through the

conduits

5 and 6 and the valve 7 so as to effect upon the upper surface of the plunger 3 so that the ram 2 may not be operated accidentally to descend downwards.

If the valve 7 is open or is not closed completely immediately after the ram 2 reached its initial uppermost position so as to lower the supporting member 10, the

high pressure of the chamber 1 flown back through the conduits and 6 and the valve 7 effects to actuate upon the upper surface of the plunger 3 so that it initiates to descend the ram 2 accidentally causing its dangerous operation. In this case, as was described hereinbefore, when the supporting member of the ram 2 reciprocates up and down by means of a mechanical force such as the crank 12, it moves downwards or in such a direction that it separates from the ram 2 immediately after it reaches its initial uppermost position so that it removes the supporting operation of the ram 2. Accordingly, the valve 7 must be closed immediately after the supporting member 10 reaches its uppermost position. If the valve 7 closes before the ram 2 reaches its uppermost position, the gas enclosed in the cylinder 4 cannot return through the

conduits

5 and 6 and the valve 7 to the chamber 1. Furthermore, the plunger 3 of the ram 2 is not yet reached to its uppermost position or its inner uppermost position, accordingly the compression occurs in the cylinder 4 by the plunger 3. Also, if the valve 7 closes after the ram 2 arrives at its uppermost position, the gas flown back through the

conduits

5 and 6 and the valve 7 initiate to operate accidentally the ram 2, since the supporting member 10 initiate to descend before the valve 7 closes. From the reason described hereinbefore, it will be understood by those skilled in the art that it is very important to adapt for the crank 12 to be able to further raise its stroke D even after the ram 2 reaches to its uppermost position relative to the movable frame 10a.

When the crank 12 initiates to descend after it reaches its uppermost position, since the supporting member 10 initiates to descend in a state that the ram 2 integral to the stem 8 is left from the member 10 without any further support the stopper piston 17 tends to descend by the hydraulic pressure applied thereabove, the movable frame 10a falls down together with the ram 2 by its weight so as to balance with the cushion 26 to stop at the normal position A (frame descended completely in FIG. 6, and illustrated by numeral VI in FIG. 7). The crank 12 will further descend, accordingly the supporting member 10 continues to descend, after the movable frame 10A stabilize at its normal position A, the stopper piston 17 is pressed upwards by the hydraulic pressure applied therebeneath (illustrated by numeral VI' in FIG. 7), and returns to its initial state shown in FIG. 1.

Thus, as was described hereinbefore in the embodiments, hydraulic pressure stopper means comprising the stopper piston 17 and the hydraulic pressure cylinder operates not only as the stopping mechanism for the movable frame 1011, but to allow it to be cushioning function in the stroke D after the ram 2 reaches its uppermost position relative to the movable frame 10a. Such a cushioning function may be separated therefrom, and another hydraulic pressure means may be provided for the same effect of the function.

In FIG. 8, another embodiment for the above-mentioned means to effect separately the cushioning function is shown in addition to the previous embodiment in the high speed returning impact forming machine in which a cushionng mechanism or hydraulic pressure means 29 comprising a cylinder 30 and a piston 31 is adapted to be inserted between the connecting rod 13 and the supporting member 10 for the stem 8. That is, when the ram 2 returns to its uppermost position the stopper piston 17 effects to stop upwards movement of the movable frame 10a and after the ram 2 reaches its uppermost position relative to the movable frame 10a, in the raising stroke D of the crank 12 said piston 31 effects to cushion therebetween. In this case the movable frame 100 does not raise upwards, but it is equivalent to the cushioning function against the jacking mechanism.

As was described in detail hereinbefore, this invention eliminates the upward movement of the movable frame together with the raising ram immediately after the impact forming operation has done in the machine by mere provision of the stopper mechanism so that the relative motion between the ram and the movable frame is enabled. Further, it makes possible to separate immediately the impact formed product from the mould, and allow the movable frame to operate sufficient reaction upon the operation. When the ram returns to its uppermost position, even after the ram reaches its uppermost position relative to the movable frame, it enables further the cushioning function against the jacking mechanism between which the operation of the valve for communicating between the high pressure chamber and the upper portion of the cylinder for operating the ram is extremely usefully effected positively and accurately.

This invention is not limited by providing the stopper means above the movable frame, which means may be disposed in any position or the construction of which is not limited by utilizing fluid pressure and mechanical means may be used.

What is claimed is:

1. High speed returning impact forming machine comprising a gas pressure chamber containing high pressure gas, a ram adapted to be actuated at a high speed by gas pressure in said chamber, a plunger provided on said ram, a cylinder for receiving said plunger provided on the top wall of said chamber, a valve for communicating the flow of said gas pressure between said chamber and said cylinder of each other, conduits for connecting between the upper portion of said cylinder and said chamber, a stem longitudinally extended upwards from the top of said ram having a head on the top, a ram supporting member driven laterally for raising and releasing said ram, means for driving laterally up and down said member, means for driving said valve open or close, said means for driving said valve being operated so that it close immediately after said plunger contacts said cylinder, a movable frame being disposed laterally movably upward and downwards inside a guide of a fixed frame and supported by a cushion at its lowermost portion, and hydraulic pressure stopper means disposed above said movable frame and secured to the fixed frame, said stopper means being operated so that when the ram returns upwards metal moulds separate immediately from each other.

2. High speed returning impact forming machine as set forth in claim 1, in which said stopper means comprise hydraulic pressure cylinder disposed fixedly downwards to the upper portions of the fixed frame, stopper pistons being inserted to said cylinders respectively, and rods adapted to be integral to said piston, said rods being projected downwards and disposed opposite to the upper surface of said movable frame, thereby enabling to stop said movable frame moving upwards.

3. High speed returning impact forming machine as set forth in claim 1, in which said pistons of said stopper means are adapted to be able to laterally move upwards and downwards by applying hydraulic pressure from the upper or lower portion of said cylinder.

4. High speed returning impact forming machine as set forth in claim 1, in which said stopper means are disposed so that the distance between the lowermost portion of said rods and the uppermost of said movable frame balanced with said cushion is larger than the bounded height of said movable frame from the normal level caused by the reaction of said ram descended.

5. High speed returning impact forming machine as set forth in claim 1, in which said stopper piston of said stopper means is adapted to be disposed at its lowermost position immediately before said supporting member initiates to contact said head of said stem on the Way moving from its lowermost position.

6. High speed returning impact forming machine as set forth in claim 1, in which said stopper pistons are disposed so that when said plunger of said ram reaches its uppermost position in said cylinder said crank enable to raise further integrally with said supporting member together with said ram on opposing to the hydraulic pressure in upper portion of said stopper means in its rested stroke.

7. High speed returning impact forming machine as set forth in claim 1, in which hydraulic pressure means are disposed between on the top of said means for driving said member and the lowermost portion of said member, said hydraulic means being so operated that said means for driving said member further move upwards to the top during a predetermined time after said ram integral to said member has reached its uppermost position.

8. High speed returning impact forming machine as set forth in claim 7, in which said hydraulic pressure means comprises a piston provided on the top of said means for driving said member, a cylinder for receiving 1 said piston provided on the lowermost portion of said member, passages bored longitudinally along with said member and conduits for connecting the ends of said passages and hydraulic pressure source.

References Cited UNITED STATES PATENTS 3,103,136 9/1963 Bollar 72453 3,105,414 10/1963 Cvjetkovic 72453 3,158,048 11/1964 Bollar 72453 3,194,049 7/ 1965 Riemenschneider 72453 3,352,143 11/1967 Bollar 72453 3,354,693 11/1967 Asari 72453 RICHARD J. HERBST, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

US. Cl. X.R. 72453; 100-269