US2349916A - Power press - Google Patents

Description

May 30, 1944.

STACY PowER PRESS Filed April 9 1940 4 sheets-snaai 1 La T. F. STACY POWER PREs$ May 3o, 1944.

4 Sheets-Sheet 2 Filed April 9 1940 ANQ /m/EA/fge. Q?,

May 30, 1944. T F STACY 1 v l2,349,915

POWER PRESS Filed April 9, 1940 4 sheets-smetta /N VEN fc3/Q.

r 4 May 30, 1944. T .Q 5mmv 2,349,916

POWER PRESS Filed April 9, 1940 4 sheets-shea 4 126 R99-- 5 ufff gf 9i w /N V545/Toe.

Patented May 30, 1944 UNITED ASTATES PAT ENT orales rowaa mass Thomas Stacy, Piqua, Ohio, aasignor tok The grkcinch Oil Mill Machinery Company, Piqua,

Application spi-n s, mo, semis. sessi: A

(ci. 1li-1s) Claims.

This invention relates to presses and more particularly to those actuated by hydraulic means. It also reiatesto a tilting' head press. in which the press head is shifted or tilted'into an inclined or other convenient position when the i press is opened.

Another object of the invention is to provide.

an improved press in which the head may be shifted into and out of pressing position, and which will be exceptionally rigid, convenient, rapid in'operation, and simple and inexpensive in construction.

Another object of the invention is to provide an improved press of the type in which thepress head is shifted between a pressing position and another position in which the mold section carried by the press head is more readily accessible, with which a pressing operation cannot beinitiated -until the press headis in full pressing position, with which the press head will be locked in the pressing position during a pressing operation,with which the sequence oi' events after initiation of a cycle of operation will bees automatic as possible, so as to cut'down thetime of a cycle of operation oi.' the press, and which will be relatively simple and inexpensive.

Another object of the invention is to provide an improved press in which the ram when advanced into pressing relation, after encountering a predetermined resistance, will be given slight retractions and readvances repeatedly for a predetermined extent. either of time or number of retractions and readvances. and'then advanced in a full pressing operation, and' with which the duration of the pressing operation may be terminated after a predetermined condition `of operation, such as after theblapse of a predetermined interval of time following the initiation of the pressing movement. i

Otherobjects and advantages will appear from the followingdescription of some embodiments of the invention, and the novel features will be particularly pointed out in connection with the appended claims.

In the accompanying drawings: I

Fig. 1 is a front elevation of a tilting head press constructed in accordance with this invention, the platen being retracted and the head in pressing position Fig. 2 isk a side elevation'of the same;

Fig. 3 is a sectional elevationthrough the tilting head portion of the same, the section being taken approximately along the line 3 3 of Fig. l, tbut with the press head in tilted or open posiion;

Fig. 4 is a sectional elevation through a portion o f the mechanism of Figs.V 1 to 3 to show the mechanismior retracting the platen;

Fig. 5 is a sectional elevation similar to Fig. 4 but illustrating an operationin which the molded articles are ejected from the dies or mol'ds;

. Fig. 6 is a sectional elevation through the press,

.the section being taken `approximately along the line I--i` of Fig. 1, but with the parts in the positions taken during a pressing operation; Y

Fig. 7 is another sectional elevation at right angles to that .of Fig. 6, the section being taken approximately along the line 1 1 of Fig. 6;

Fig. 8 is a schematic diagram illustrating mechanism associated with the press of Figs. 1 to 7 for controlling the operations thereof in accordance with this invention: and

Fig. 9 is a similar schematic diagram, but illus-V trating a slight modification thereof.

Referring ilrst to Figs.'1 to 7, the tilting head r press illustrated is ofV the side plate type such as disclosed for example in my prior U. S. Patent No. 2,013,587. Such a pressincludes a pair'of heavy, metal plates l0 and Il (Fig. l) which are disposed in upright, parallel positions, side by side but spaced apart. A cylinder head I2 is disposed between the upright plates IU and Il at their lower ends, and coupled thereto in any suitable manner such as explained in my prior patent, it being understoodthat the head is notched into the side plates. The cylinder head thus serves as a rigid connection between the side plates Il and II at their lower ends. A platen I3 V(Figs. 1, 6 and 7) is disposed between the plates I0 and II andguided thereby for vertical movement. The platen I3 is operated by a piston or ram It (Figs. 6 and 7) which depends into the open vupper end of` the cylinder head I2, there being. a suitable packing gland I5 surrounding the piston I4 at the entrance to the cylinder head I2. o l l The upper ends of` the side plates IU and l l are connected by heavy bolts I6 and Il having nuts I 8 and I9 on their outer ends and bearing against Hinged on the front rod or bolt I between the plates Il and I is a frame or casting 28 (Fig. 1)

. which has an upper cross bar member through which the bolt I4 passes, and this cross bar member extends between the inner faces of the side plates I 8 and Depending from this cross bar portion are two arms 2| and 22 (Fig. 1) which are parallel and spaced apart, and also -received in notches or grooves 23 and 24 respectively of a press head 25. A bolt or pivot rod 25` passes through the press head 25, the notches :23 and 24 and the free ends of the arms 2| and 22 so as to provide a hinged connection between the free ends oi' the arms 2|' and 22 and the forward zone of the press head 25.

Hinged upon the rod or bolt I1 are a pair of arms or links 21 whose lower ends are similarly received in recesses or notches 28 (Fig. 7) in the rear of the press head 25. A bolt or pivot pin 29 passes through the vrear portion ofthe press head 25, the recesses or notches 28 and the depending `ends ofthe arms 241 so as to provide hinged connections between the links 21 and the rear portion of the press head 25. The 'distance between the pin 29 andthe rod |71, which is the pivotal connection at the rear of the press head, is preferably greater than the distance from the pin 25 to the pin or bolt |5 so that in effect .the hinge connection for the yfront of the head 25 is shorter.

than that for the rear of the press head for a reason which will appearfpresently.

Thev frame or casting 25 is also provided with a rearwardly extending' arm 3 0 (Figs. 2, 3 and 6) ,approximately midway between the side plates l0 and Il, by means of whichthe press head may be shifted or tiltedinto an exposed position for access to its mold carrying face. A plate 3| exy Y tends across and connects th'e upper end edges of the side plates l0 and and secured to the underface of the plate 3| are a pair of spaced, parallel guide rails 32 (Fig. 1) which run forwardly andv rearwardly, and slidingly support a member`33. This member 33 is hlngedly connected, at its forward end, by a pinV 34-to a pair of links 35, the other ends of the links being pivotally connected to opposite sides of the arm 38 by a Vpin 38. Also connected to the slidable member notched es et a2 (Figs. 1, s and 6). when the piston 31 is forced to the right, in Fig. 3, by ilui!! under pressure. admitted to the left hand end of the cylinder 38, such as through pipe 43, the member 33 will be retracted and will rock the frame (clockwise in Fig. 3) and carry the press head into the position shown in Fig. 6, in which its lower face 44 is directly across and normal to the direction of travel of the platen 3.

Cooperating mold sections 45 and 45 may be carried by the platen i3 and press head 25 respectively, as shown in the drawings, so that when the platen I3 is shifted upwardly, the molds will be first engaged and then the material in- 33 throughthe pin 34 is a piston rod 31 (Fig.'3)

which enters a hydraulic cylinder 38 also securedY to the plate 3| and to'a'connecting bar 39 extending across between the plates I0 and adjacent their rear'edges. 'I'he piston 31 terminates withl in the cylinder 38 in a pistonV head 40, so that the piston 31 will be shifted endwise in one direction orV the other, depending upon whether an Vactuating fluid is admitted-to one end orfthe other of thecylinder 38. Y

When actuating fluid is admitted to the rear end of the cylinder 33, such as through a pipe 4|,

the piston 31 will be forced outwardly and will carry the slidable member 3 3 with it, rock the. frame or casting 28 through the arm 30 thereof in a manner to carry the depending arms 2| and 22 rearwardly and upwardly, and tilt the press head 25 into the inclined position shown in Fig. 3. During this movement the links 21 swing rearwardly, and when the links 21 are made longer than the arms 2| as shown, the press head is tilted into a substantial acute dihedral angle to the horizontal or inclination, with a lesser extent of rocking movement of the frame 20 than would be otherwise necessary. To enable the head to move into the substantial inclination shown in Fig. 3, the central portion of the head 25 maybe terposed incr between the mold sections compressed in a manner usual in this\ type of press and which per se is not a part of this invention.

Each side plate I0 and is provided with an open window or aperture 48 (Figs. 2 to 6) Vand a cross bar 49 extends across each window 48 on the inside face of each side plate I0 and The portion of each bar 49 passing its related window 48 may be made wider than the others, as at 58, and to these wider portions are secured duplex cylinders 5| which are disposed within the openings 48 and extend vertically therein. The wider portions 50 of the cross bars 49 pro. vide for greater rigidity of anchorage of the duplex cylinders. Each duplex cylinder 5|"is provided with a lower piston chamber 52 and an upper chamber 53, it being understood that there is a duplex cylinder 5I in each window 48. AA piston rod 54 extends outwardly through the bottom end yof each lower chamber 52, and a larger but similar piston rod 55 extends upwardly out of each upper chamber through the platen |3Vis a knock-out bar 55, the ends of this bar extending -into and through the open windows 48 into positions below the lower ends of the piston rods 54. 'I'he knock-out bar 55 is free to move vertically in the platen to a limited extent, as shown particularly in Fig. 6, and within the platen this bar 55Yengages knock-out pins 51 which passupwardly into the lower mold 45. When the molds are open the upward movement of pins 51 by bar 55 serves to ejectthe molded articles from the mold cavities as usual in presses of this type. When the bar 55 is in its lowermost position, as'shown in Fig. 6, it releases the pins 51 and they are then retracted into pci sitions'ush with the mold cavity. I

V Parallel rods 58 (Figs. 2, 4 and 5) are disposed along opposite sides of each duplex cylinder 5| and are mounted for endwise sliding movementsI in lugs 58 projecting exteriorly from the casing of the duplex cylinder 5|. These rods 58 are conn another at their upper ends by a nected to one bar or yoke` 50 and at their lower ends by a bar or yoke 6|. Depending from the yoke 80 into each chamber 53 of the duplex cylinder 5| is the piston 55. VEach bar or yoke 5| the lower ends of a pair of rods 58 extends beneath the adjacent end of the knock-out bar 58. A pipe 53 Vopens into the lower chamber 52 of the duplex cylinder 5| so as to supply actuating iluid to the'chamber 52, and a similar pipe 54 opens into the upper chamber 53, so as to supply actuating fluid. to that cylinder. The pipe 54 leads to a suitable valve, which when operated into one position will supply actuating uid under pressure to the chamber 53 and when operated Vinto ing to the chamber to the chamber 52 53. Extending across and which connects wardly and through the elector ber Il it also urges downwardly the yoke il Vand the rods Il. Since the elector bar Il is carried in the platen it also forces the platen and ram piston I4 downwardly. The two chambers Il and the pistons S4 thus constitutel a pair of pull-back rams for aiding in retracting the'platen, and they may be under a continuous pressure, as explained hereinafter. The chambers 53 and the pistons 55 therein', together constitute knock-out or ejector rams.

Referring now to Fig. 8, a schematic `diagram of the operating circuits and mechanism is illustrated, and will now be described.- An operating iiuid under a relatively low pressure, such as 250 pounds per square inch, is supplied fromany suitable source through a pipe line 05, and a source of actuating nuid under a considerably higher pressure, such as 1500 pounds per square inch, is supplied from any suitable source such as through a pipe 66. 'I'he pipe li leads to a valve 61 which may be of any suitablel construction, one example being disclosed in my prior U. B.

f Patent No. 1,901,131, except that ln place of the' manual operation oi the controlling valve element thereof there is provided a pilot cylinder 6l 'at one end of the valve housing. The piston in cylinder 68 when under pressure forces the valve element 69 in one direction to initiate an advance of the platen. 'I'he valve element 6l extends out of the valve chamber at both ends so as to be balanced, one end being operated by thepilot cylinder 68 and the other being connected to one arm of a bell crank lever 1l by a pin 1l carried by the. element l! and Operating in an axially extending slot12 in bell crank 10. The bell crank 1B is pivoted at v13, and its other varm has a slot 15, running radially tothe pivot 13, which slidingly receives a pin 1G carried by a safety locking bolt or member 11 on one of the press side plates` such as il. f

The locking bolt 11 is slidingly mounted in an: aperture in the plate il, so as to pass Atl'lerej-f through and be removably receivedinfal locke"v ing recess 18 provided in the press-headillsuch',

as at approximately-the center of .the pini. A l

spring 1s acting on the locking bolt 1.17,' urges it into retracted position andthrough the bell crank4 1il-urges the valve element Il into one limit of..

,its movement in the valve l1 in which it terminates an advance of the platen and' allows a return movement thereof.fr When the pilot cylinder S8 is energized, it shifts the valve element 69 in a A pressure responsive switch It is connected by a pipe Il to the pipe "leading to them ram cylinder head Il, lo as to be responsive at! y ally times directly to the pressure in the cylinder,

mally connects contacts 88 and 89 when the pres:V e'

sure onthe valve isbelow a selected or predetermined pressure for which it may be set. When the pressure in the pipe 86 exceeds that selected pressure, the bridge 81 moves out -of engagement with the contacts 88 and 89 and opens a circuit between them for a purpose which will appear later.

In connection with this embodiment of the invention, I employ a pair of similar timers A and B, the timer A being connected to regulate the period of the pressing operation and the timer B being used to incapacitate the pressure responsive switch I5 after the lapse of a predetermined interval of time which is less than that for which the timer A isset. These timers may be oi any suitable type. and are available in the open market. One-example of such a timer is vdisclosed in U. S. Patent No. 2,175,865 of October A10, 1939, to which reference may be had for more detailed information., `Such a timer may be a synchronous motor driven, time delay relay which includes a contact Voperating mechanism driven by the motor through an electro-magnetic clutch.

It is entirely automatic in action,requiring only the closing or opening oi.' a control circuit to initiate or terminate `afcycle of operation. The timers A and B in Fig. 8 are shown only diagrammatlcally and inasmuch as 'both timers are of similar 'construction but are merely connected difierently in the system,-it is only necessary to describe the circuit connections oi' these timers.

Thetimer A includes" a clutch coil 90 and a l`'iis motor-9L one. side of the clutch aidefgf the'motor ,gl being contssi'ihe which sun- .and which is operatedintofclosedposition by the lpress head 2S asgthe `aches closed or press- `inglosilllon.v Y ,e de of theswitch is connected by a wirel'llftortheline wire L2.- Thus as the press "head 37E-,moves into closed position it closes the switchgffand completes a circuit I through'the clutchleoii .SII-'between the line wires Le and Lz. when die clutch con so is energized it operates touplethe-motor 9i to the timing mechanism. tnotzshcwnij and also shifts a switch The pipe B3 may be connected to the pipe 8l directly, so that there will always be a relatively low pressure acting on the knock-out bar 56. and urging the platen intoretracted position, but because of the low pressure and small pressure area on which it acts in cylinders $2, the pressure in` when aid 'may be of any suitablel construction. this type of valve being very common in the art.

member ,Stintofengagement with a contact terminal il which is connected by wire IM to the other side of,` the motor 9i. connected by a wirerilli to the line wire L? and `hence when it is shifted into vengagement; with the terminal 99 a branch circuit is completed fromline wire Ll through wire 92 to motorill,

initile als etggterminl @when 9 The time serirmeeirpsiasted ithe:staten meinte r'llie terminaisons to ne side of asciende los, the other side of that solenoid being connected by a wire lill to a 5 switch member l02 of timer B which corresponds The member 98 is ie the switch member le: si

/guish these parte from the y is connected bya wire ||3 to line wire Y wire |24 to the line wire LI.

lplied thereby.

timer A. In timer A the switch member III! le connected by a wire |33 to the wire I3| leading to line wire L2. The solenoid |03 above referred to is connected -to operate a valve element Ill. provided in a valve casing III. against the action o! a spring III from the position shown in i'ull lines in Fig. 8 into a position in which the annular groove in the spool of the valve |43 connects an air supply pipe ||2 to apipe II3 leading to the pilot cylinder 33. The pipe |I2 receives air under pressure from any suitable source suchas a shop air line, and it will be seen that the solenoid I controls the admission of air under pressure to the pilot cyl- 'inder B3 or discontinues the air and vents the pilot cylinder. The' spring I|I acts between a p head ||4 on an extending stem of the valve element Il! and the casing I I to urge the valve element |33 into the full line position whenever the solenoid I is deenetgized.

'me timer'B is similar in construction to the timer A and corresponding parts are given corresponding reference, characters but to lwhich the prime, mark has been added in order to distincorresponding parts in timerA. One side oi the clutch coil 3l' and one side o! the motor II are connected bywire III to the line wire LI and the other side of the clutch coll 33' is connected by wire |I3 to the wire 33. 'Ihe clutch coils 3l and 3|' are therefore connected in parallel to one anotherbetween the line wire LI and the wire 33. The member 33' is connected by a wire ||1 to line wire L2. The contact |33' LI and the contact |44' is connected by a wire ||3 to contact Il of the pressure responsive switch 45. The contact 33 of the switch 3l is connected by wires, such as the line wire L2. is provided with a normally closed or emergency switch C, before anyv connections are made to the circuits supand this line wire also includes One ot the line in series therein a normally open or main switch D which I|1,I1,and III. Y

Ilie switch D is connected by wire |2| to one side of another solenoid |22. the-other side of that solenoid being connected by a wire |23 to the line wire LI. The wire. |2| is also connected is beyond the connection to wires to contact terminali "of a switch |25 which. is!V into closed position in any suitnormaliy urged able manner such as by spring |24, and which is disposed to be forced into Yopen position by the platen I3 when the latter kreaches a desired retracted position. The other side of switch |23 is connected by a wire |21 to the wire |3| leading to the line wire LZ-beyond the normally closed switch C. The solenoid |22 is connected to operate a valve element |23 which may be of the spool type and which reciprocates in a casing |29. 'I'he valve element |23 is urged into a normal position by a springl3l acting between a head |3I Von the valve element land the casing |29, which normal position is shown in full lines in Fig. 8. When the Asolenoid |22 is energized it moves the valve V|35 with the exhaust vent will torce the piston element m against the action or spring m inte valves are common in the market and therefore a detailed description is omitted.

When no pressure is applied to the pilot cylinder' |33, the valve element (not shown) of the it to switch 95, then by wire andere.

valve |34 le yieldingly urged by a suitable spring (not shown) into a position in which it connects a pipe I3! leading thereto from one end oi' the cylinder 33 with a branch pipe "a leading to the pipe Il which delivers the actuating iluid under relatively high pressure to the valve 41. When the pilot cylinder |33 is subjected to air under pressure. delivered thereto from the pipe |32, it shifts the valve element within the valve |34 into a position to disconnect the pipe |35 from the pipe 66a and to connect the pipe |35 to an exhaust vent |36. A pipe |31 connects the pipe (i6-to the opposite end of the cylinder 33 through which the piston 31 extends, so as to exert a continuous pressure on the piston head 40 tending to shift it to the right in Fig. 8 and move press head 25 into the pressing position. Inasmuch as the eilective pressure area. of the piston head 4I| on the side having the piston stem 31 and the connection thanthat on the opposite face ot the piston, the piston 4l will be moved to the left in Fig. 8 against the action of the pressure delivered by pipe |31 whenever the valve |34 ls operated to admit the pressure `from the same source 66 to the chamber 33 through pipe |35.

In the operation of the press under the system shown in Fig..8, let it be assumed that the parts are in the normal inactive position shown in full lines in Fig. 8, at which time it will be noted that the switch |25 is open, press head 25 is in the The valve elements |09 and |23V will also be in the full line positions. There will be no pressure on the pilot cylinders 33 and |33 and the safety bolt 11 will be in withdrawn position, as shown in full lines in Fig. 8. The switch D will be in open position and the switch C will be clsed. Y

To initiate a pressing operation, closes the switch D and holds it closed until after the rain I4 has shiftedV the Platen I3 11D- wardly. or in an advance or working direction, far enough to allow the switch |26 to close. when switch D was closed it completed a circuit through line wire L2, switch D- wire I2I, solenoid |22, wire |23 to line Wire LI. hold |22 when thus energized will operate the valve element |23 out of its full line position the attendant into one in which it connects the branch pipe II2a, carrying air VVunder pressure, to the pipe |32 leadingto the Vpilot cylinder I 33; This causes air under pressure to be delivered to the pilot cylinder |33 and causes an operation of the valve |34 in a manner to interrupt the connection between pipes 66a and |35 and to connect pipe |36, whereupon the |31 entering cylinder 33 40 to the right (Fig. 8) and swing the press head 25 into the closed position shown in Figs. 1, 2, 6 and 7.

' As the press head 25 moves intov closed position it engages and operates the switchst into closed position which then completes another circuit as follows: from line Wire Li through wire 92, clutch coil 30, wire 93, switch 35, wire 8l' to line wire L2. It also completes a branch circuit from line wire LI through wire IIS, clutch coil wire IIS then to'wire 93 and through 31 to line wire iluid pressure in pipe L2 as previously described for 9| of timer A. When this circuit is completed the clutch coils 90 vand 30 of the two timers to the pipe |31, is smaller Y the .clutch coil will couple the motors 9| and 9| to the timing mechanism and will also cause the members 98V and 98 to engagethe contacts 99 and 99 completing circuits through the motors 9| and 9|'.

. mechanism of the timers which is thus rendered effective as explained in U.A S. Patent No. 2,175,865 above identified, will shift the switch members |02, |02' from the full to the dotted line positions in Fig. 8. When this happens a circuit will be established as follows: from line wire L2 through wires |0| and |08, switch member |02 of timer A, contact |03wire |05, solenoid |06, wire |01, switch member |02' of timer B, contact |045, wire ||9, contacts 88 and 89 of switch 85, wire to line wire LI. 4,

Solenoid |06, being energized in this manner, will operate the valve element B09 out of Vits full line position and will connect the pipe |2 carrying air under pressure to the pipe ||3 leading to the pilot cylinder 68. This will operate the valve 61 and cause a movement of the valve element 69 downwardly in Fig. 8, rockthe bell `crank `10 and shift the safety locking bolt 11 into the recess 18 and thus lock the press head against movement outof pressing position. At the same time that the valve element 69 is operated from the pilot cylinder 68 in this manner it also connects the pipe 8| leading from the pipe 65 carrying low pressure actuating fluid to the pipe 80 going` to the cylinder head I2,

allowing spring 18 to retract `the safety bolt 11, cut off` the flow of actuating fluid to the pipe 80 and theram I4, and vent the pipe 80 to the exhaust pipe |38, whereupon the pressure falls in cylinder head I2 and the platen starts to open. As the platen starts to open, however, the pressure falls also in switch 85 and this switch then immediately recloses and recompletes the circuit through the solenoid |06, and this again shifts the valve element |09 into position to reconnect the pipes ||2 and ||3 and reapply pressure to the pilot cylinder 68. The valve element 69 of valve V61 is again moved to readmit fluid under pressure to pipe 80 and cause a readvance of the platen. When the pressure again builds up, switch 85 will again open and momentarily deenergize solenoid |06, and this cycle of openings and closings of switch 65 is repeated.

These slight-retractions and readvances of the platen in this manner are called bumping" and bumping is frequently used in the rubberA industry to allow escape ofV air from the molds at intervals after pressure is` applied and before final pressure is applied to the material in the molds. 1

After the lapse of a selected interval of time Yfor which the timer B is set, and which time interval may be varied by a suitable adjustment of the timer B, the timer B times out andin doing so theswitchfmember |02' is shifted from the dotted line' position back into the full liner position `shown in Fig. 8, which interrupts the circuit through the switch 85 and instead completes a shunt circuit as follows: from line wire LI through wire I|8, contact |03' of timer B,

`switch member |02', wire |01, solenoid |06, wire and the fluid thus delivered to the cylinder head I2 elevates or advances the ram Ii and platen When this advance is sufficient to allow switch |25 to close, another circuit is completed as follows: from line wire L2 through wires |0'I, I21,`switch |25, wire |2'I, solenoid |22, wire |23 to line wire LI. Thus the switch |25 shunts the switch D and thereupon the switch or button D can be released and allowed to open because the solenoid |22 will continue to be energized by the closing of the shunt switch |25.

The platen I3 continues to advance and when the resistance encountered `causes the back pressure in the pipe 80 -to `increase to a selected extent, the valve 61 will automatically connect the` pipe 66 carrying actuating fluid under high pressure to the pipe 80, an automatic check valve leading to pipe 8| automatically closing to prevent flow of the high pressure actuating fluid through pipe 8| into the pipe 65 carrying fluid under low pressure.` The high pressure then continues to advance the platen I3. When a desired resistance is encountered which may be before or after the high pressure has been admitted to the cylinder head I2, depending upon the setting of the switch 85, the pressure exerted on the switch f85 will open the circuit between the contacts 88 and 89 by carrying the bridge 81 out of engagement therewith, and thisinterrupts the circuit of solenoid |05 through the wires ||9 and |20. f

When the circuit of solenoid. |06 is opened in this manner the spring |II immediately shifts the valve element |09 back into the full line position in which the air pipe ||2 is disconreleases the pressure in the pilot 'cylinder 68 |05, contact |03, switch member |02 and wires |08 and |0| to line wire L2. Thus the solenoid |06 now remains energized free of the control of the switch 85, and the pressure in pilot cylinder 68 of valve 61 will remain continuous and this will result in a',y continued advance of the platen I3, the latter portion of this advance being under the high pressure fluid derived from pipe 66. This advance of the platen `I3 will continue until the timer A times out at the end of a time interval for which it has been set, and which time interval may be varied by suitable adjustment of timer A.

when timer A times out, it shifts the switch` member |02 from the dotted line position into the full line position in Fig. 8 which breaks the circuit through the wire |08 to wire |05 and thus interrupts the circuit through the solenoid |06. The latter is then deenergized and the valve element |09 is shifted into a position to relieve the air pressure in pilot cylinder 68,'whereupon the safety locking bolt 11 is retracted from the` press head 25, the supply of actuating fluid under' pressure is relieved from the pipe 80, and the cylinder head I2 andthe pipe 80 are vented through the pipe |38 which allows the escape of the Vfluid from cylinder headl |2'and a descent ot the platen. It will be noted Vthat the pullback cylinders 52 are continuously connected to the` pipe carrying an actuating fluid under low pressure, and therefore as soon as the pressure in cylinder head |2 is released, the pressure in push back cylinders 5,2 will be active in accelerating the retraction of the platen i3 and ram piston Il. This will continue `until the switch |25 is opened at approximately the end' of the retraction of the platen. The opening of switch |25 deenergizes the solenoid |22, and thereupon the spring |30 shifts the valve element |28 back into'the full line position in which it disconnects the branch air supply line ||2a from the pipe |32 and ventsl theV4 latter, thus releasing the air pressure in the pilot cylinder |33 of valve |34. The valve' |34l 5 then automatically connects the pipe SiS to the pipe |35 and uid under pressure then ilows into the righthand end of cylinder 38 in Fig. 8. shifting the piston 40 to the left Vand rocking the press head 2s intol the tilted position. This 10 last movement of press head 25 into tilted posi-` .tion releases the switch 95,which Vthereupon automatically opensl and thus opens the circuit throughl'theV clutch coils 88 and 80' and these coils when deenergized disconnect the motors 8| 15 and 9|' from the timing mechanism. The switch members 98 and 98' are at the same time released and open the circuits t'o the motors of the timers. The parts are then in the normal idle position Vfrom which the cycle was started. 2G 'n If atV any timefdurlng the operationV of the system, one desires to terminate it without waiting i'ortheV timers to operate, ope merely operates t the safety switch C which automaticallyopens Vall of the circuits and causes an immediate re- 26v turn of the platen I3 to retracted position. The switch `C should, however, be Yheld openv until the platen I5 has completed its retraction movement. i

A After the pieten ls nos been retracted and 30V Y the press head 2.8 swung into the tilted or inclined position` the attendant may'operate the valve "82 and 'cause delivery of low pressure actuating fluid to the knock-out cylinders 8l. The

pressure therein forces the pistons 55 outwardly 35 and since they are larger'than the pistons 84 (the pressure per unitY area being the same in.

both sets of cylinders 82 and I3), the :pistons 58 Vwill overcome the resistance ofl pistons I4 andV will shift the frame formed of the bars or yokes 80 and 8| and the rods 54 upwardly,

lifting the knock-out Ybar 88 upwardly. The bar 56 shiftsthe knock-out pins 51 (Fig. '1) upwwardly in a manner to eject the Imolded articles from the mold section ,carried bythe platen.

In the embodiment of the invention shown in Fig. 9. the mechanism is generally the same v as in Figs. 1 to 8 eirceptthatV the switch Il conthat in place of the motor 9|' in Fig. 8. a mag- 55 net |42 is substituted. The magnet |42 recip` rccates a pawl |43 against the action of a spring |44, and the pawl |43 at each operation engages the teeth ci' a ratchet wheel |48 carried on a shaft |46, and imparts increments of rotation 00 to the shaft |48. .The shaft |48 is connected to the timing mechanism by clutch mechanism controlled by clutch coil 98 in the Vsame manner that the motor 9|' of timer B was connec to the timing mechanism by the coil Il', so .05.

that after a predetermined extent of movement of the shaft |46, the switch member |41 corresponding to the switch member |22' of timer B is rshifted fromV the dotted line position fhtw U the fun une position shown in Fig. 9. mtl-lis 7 mechanism, however, the connectlonsto the .magnet |42 are slightly different from those to the motor 9|' of timer B and will now be described.

One side of the magnet |42 is connected by wire las to the wire us which leads to the clutch 7 con sa' 'whichA corresponds to the cou su' of timer Y B. The other side of the magnet |42 is connected by a wire |49 to the contact |48 oi' switch Il. 'I'he'contact |39 of the switch 85 is connected by a wire |50- to the wirel which leads to the solenoid |08. The switch member |41 of counter E is' also connected by wire |41 to the solenoid |48 the same as for the switch member |82' of timer B. The contact |4450! counter E is connected by a wire ||9 to the contact 88 of pressure responsive switch 8l as in Fig. 8, andthe contact |08' is connected by wire H8 to the line wire LI, as inrFig. 8. In the counter E the switch member 88' and contact 99'` are not utilized, and'may merely remain unconnected.V Otherwise than as lust described, vthe parts in Fig. 9 are` the same asin Fig. 8

and -have corresponding reference characters.

The operation of the system as modified in Fig. 9 will now be explained. When the press is idle, theswitch member |41 of counter E is in the fullline position shown in Fig. 9. A

cycle of operation of the press is initiated by closing the switch D and holding it closed until the platen has advanced suillciently to allowthe swltchd!! to close, and as soonasV the press head 28 reaches closed position it closes switch 98' which yinitiates an energization of the clutch coil 98 of timer A and the clutch coil 8l' oi.' c'ounter E. The timer A,functions in the Vsame manner as explained for Fig. `8 and in counter 'E the switch member |41 is at once moved from the full line to the dotted line position in Fig. 9. Counter E otherwise functions as does timer B in Fig. 8. except that the magnet |42 has its circuit'v opened each time that the pressureresponsive switch is opened, and'each tlmethat the magnet |42 is reenergized inV this'manner it operates the counter ratchet |48 and drives 40 shaft |44 step by step. The shaft |48 may be the same shaft'that was operated by the motor 4|' oi' counter B. After the counter shalt |44 p has been rotated through a desired extent corre- Y spondlnz to a selected number of A impulses through magnet "|42, the counter times out and the switch member |41 is shifted automatically `from the dotted to the full line position in which the switch member |41 engages contact |44' and thus shunts the switch 85, whereupon solenoid ill remains energized until the timer A times out and moves the switch memberY |82 from the dotted4 line to the full line position. The operation is otherwise the same as explained for Mg. 8. When counter E times out,l it automatically moves switch member |41 from the dotted position to the full line position of Fig. 9.

It will be understood that various changes in the details and arrangements of parte, which have been herein described and illustrated in order to explain Vthe naturerof the invention, maybe made b y those skilled in the art within the principle and scope of the invention, as expressed in the appended claims. l

I claim as my invention:

l. In a shiftable head press, a frame, a platen. a press head disposed in alinement with said platen, means for moving said platen toward and from said press head, rigid links hinged to said head, forming the sole support therefor, extending therefrom in a direction away from said platen, and at zones further from said platen than said head, hinged lto said frame von axes parallel to the axes of the hinge connections to said head, whereby pressure against said head flQm Said platen during a pressing operation will place all of said links under direct endwise compression, and means for swinging'said head by said Vlinks in a direction generally crosswise of the direction of Vmovement of said platen into and out of pressing 'position in which it is alined with said platen. i

2. In a shiftable head press, a frame, a platen, a press head generally rectangular on its pressing face and disposed in alinement with said platen, means for moving said platen toward andy from said press head, rigid links hinged to said head adjacent the corners of said face forming the sole support therefor, extending therefrom in a direction away from said platenfandl at zones further from said platen than said head, hinged to said frame on axes parallel to the axes of the hinge connections to `said head; whereby pressure against said head from said platen during a pressing `operation will place all of said links under vdirect endwise compression, said links being all 'approximately parallel to one another with two of said links at adjacent corners of said face hinged to the head on aligned axes and to the frame on aligned axes, and the links that are hinged to the other adjacent corners ,hinged to the head on aligned axes and'to the frame on aligned axes, said two links being of different length than the other links, and means for swinging said head by said links ina direction generally crosswise of the direction of move' ment of said platen into and out of pressing posi tion in which it is aligned with said platen.

3. In a shiftable head press, a base, heavy side plates secured to said base and extending therefrom in the same direction in face to face. but' spaced parallel relation to one another, a platen disposed between said plates for movement therealong in a direction toward and from said base, means on said base for moving said platen in said direction. a press Ahead disposed between said plates and toward and from which said platen moves when operated by said means, rigid links hinged to said head, extending therefrom lel to said direction of movement of said platen, said links at portions thereof away from said head and further from said platen than the hinged connections between the head and links,

being hingedlv connected to said side plates to oatingly support said head from said plates, whereby pressure against said head from said platen during a pressing operation will place all of said links under direct endwise compression, and means for swinging said head on said links in a direction generally crosswise'oi said direction of movement of said platen in a pressing operation, into and out of pressing position in which the face of said' head towards said platen is aligned with said platen and generally nor' mal to th said directionof movement of said platen. l

4. In a shiftable head press, a frame, a platen,

a press head generally` rectangularV in plan andV wise of said direction of platen movement, to provide a floating, swinging support for said head, whereby pressure againstV said face from -said links to carry 'said .headout of Vpressing position in the path of movement of said platen.

5.V In a shiftable head press, a frame, a platen, l

meansattached to said frame for operating said platen back and forth in a desired path; a press head having' apressing face toward and from which said platen moves in said path, a plurality of rigid links parallel to oneanother and each hinged atone end to said frame and at its other end to said head for swinging movement about parallel axes, with a direction of swinglngforwardly and rearwardly of the frame and wholly and Iloatingly supporting said head from said frame for movement into and out'of a pressing position in which said pressing face is across ,and approximately normal to said path and said links are all generally parallel' to one another and to said path, and extend from said head in V,directions away from saidV platen, one pair of said links having coincidentaxes oi hinging to saidhead and coincident axes of hinging to said Vframe, the other `links having similarly coin parallel relation to one another and in direcll'tions away from said platen, and generally paralinident' axes of connection to said head and frame,'wherebythe stresses created on said head by said platen during a pressing willbe transriiitted endwise through said links to said frame,

said head when in Vpressing position being disposed between said platen and ,the ends of thel links that are hinged to said frame, whereby the pressing stresses in said links `will be direct endwise compression of said links, said one pair of said links which are hinged to saidv head with coincident axesdiiering in length from the links of the other pair and means for swinging said head on said links to carry said head into a position in which said pressing face is disposed in" a different and more accessible position on. said` iframe.

6. In a shiftable head press, a frame. a platen, means attached to said frame foroperating said platen back and forth in a desired path, a press head having a pressing face toward and from which said platen moves, a plurality of links hinged to said frame and to said head for swing- -ing movement about parallel axes, with a direction of swinging forwardly and rearwardly of Vthe frame and wholly and iioatingly supporting said head fromsaid frame for movement into and out. of a pressing position iny which said pressing face is across and approximately normal to said path and said links are all generally parallel to one another and to said path, said links extending from their connections to said head in directions away from said platen in the direction of platen movement for their .connections to said frame, whereby the stresses created on said head by said platen during a pressing operation will be transmitted endwisethrough said links to said frame and cause endwise,` direct compressions of said links, two of the links supporting said head. being hinged` thereto by substanftially coincident axes and havingequal lengths but which are different than the lengths oi' the other links connected to said head, said other links being also hinged to said head by substantially coincident axes spaced from said other coincident axes, whereby when said head is swung on said links, said head will move through positions inclined to said path as well as horizontally, and into a position in which the pressing face thereof makes an angle to said path substantially different-'than approximately `90", and means for swinging said head on said links and for holding it in different positions into whichrit may be swung.

7. In a shiftable head press, a base, a pair of Vsaid base for` operating said platenback and'v forth in a desired path, a pressA head-having a pressing face, rigid `links hinged atone end to said plates-adjacent the Vforward edges thereof for swinging movement abdutv coincident axes and hinged at its other'end to said head adjacent the forward edge thereof, a rigid llink parallel, side by side upright positions, and with the faces of said plates extending in directions substantially forwardly and rearwardly of said press a platen disposed between said plates and` guided for movement along said plates, mean; supported by said base for operating said platen back and forth in a desired path, a press head having a pressing face, a pair of links hinged to said plates along the forward edges thereoi for swinging movement about coincident axes and hinged at their free ends to said head adjacent the forward edge thereof, a pair of links similarly hinged to ,saidl plates adjacent the opposite edges thereof and similarly hinged to said head along the rear edge thereof, with all of said links approximately parallel to one another when extending generally in the direction of travel of Vsa"d platen, and floatingly supporting said head with said pressing face approximately normal 20e to said path, whereby the pressure on said face by similarly hinged to said plates adjacent the rear edges thereof and similarly hinged to said head adjacent the rear edge thereof, withall of said links approximately parallel to one another when extending generallyin the, direction of travel of saidv platen, and oatingly supportingsaid head with said pressing'face approximately normal to said path, and said head-when in pressing positionr being disposed between said platen and the ends of said links that are hinged to said sideV plates, wherebythe pressure onsaid face bysaid platen during a pressingv operation will be transmitted through said links to said plates in directions endwise of said links, and means for swinging said headon said links int a position in which said pressing face is out of pressingrelation to said platen and is exposed for easy access thereto. Y' I i 8. In a shiftable head press, a base, a pair of plates connected to said base disposed in spaced,

parallel, side by side upright positions, and with the faces of said plates extending in directions substantially forwardly and rearwardly of'saiid press a platen disposed between said plates and guided for movement along said plates, means supported by said base for .operatingsaid platen back and forth in a desired'path, apress head having a pressing face, a pairof rigidlinks'each hinged-at one end to said kplate'zs,adjacentfthe forward edges thereof for/swinging movement about coincident axesfand.'eachghinged at its other end to saidhea'd adjacenttthe drward edge thereof, a pair of'linkssiinilarly hinged to'said plates adjacent the oppositeV edges thereof and similarly hinged to"'sa i,d head adjacentthe rear .edge thereof, with alltofsaid links approximately parallel to one. another when extending generally in the direction of'travel:oflsaidplatei'i, and floatingly supporting said headfwlth'gisaid' pressing face approximately'nornialgt'osaid path, wherefby the pressurepn said facekbysaidplaten during a pressing' operationwlllbe transmitted through said ylinksft'o'ffsaid plates in directions' endwise of said llnksan d means for swinging said head on saidlinks into a position in which said pressingv faceis out of pressing relation to said platen and-,is exposed foreasy access thereto, one of saidpairs. of said links being shorter than theother psi-r-wherebywhen said head is swung on said links, said head will-be ltilted into a position in which said pressing face makes an acute angle to said path'.

9. In a shiftable head press, abase, a pair of platesconnected to said base disposed fin spaced,

said platen during a pressing operation will be transmitted through saidlinks to said plates in directions endwise of said links, means for swinging said head on said links into a position in which said pressing face is out of pressing relation to said platen and is exposed for easy access thereto, and means carried by ai; least one of ,said plates for releasably engaging with said head for locking it against swinging movement with said pressing face approximately normal to said path. c

10. In a shiftable head press, a frame, a platen. means attached to said frame for operating said platen back and forth in a desired path, a press head having a pressing face, a plurality of links hinged to said frame and mounted to swing about parallel axes in a direction from front to rear of said press, some of said links being attached tol said head adjacent the forward and some adjacent the rearward edges of said face so as to wholly and floatingly support said head from said frame, with said pressing face approximatevlynormal to said path, and said links extending generally parallel to vsaid path, whereby the pressure on said head from said platen during a pressing operation' will be transmitted solely through said links to said frame in directions generally lengthwise of said links, means connecting together the links attached to said head adjacent one of said forward and rearward edges 'of said face of said head, and power actuated means connected to said connected links for rocking the same about their connections to said frame, the links attached to said head adjacent one edge of said face being shorter than the other links, whereby said head may be swung by said power actuated means from a position in across and normal to said path into a position in which the plane of said face makes an acute angle with said path.

11. In a shiftable head press, a pair ofuprig'ht, parallel heavy plates spaced apart side by sido and with the faces of said directions forwardly'and rearwardly of said press, a cylinder head disposed between and connecting said plates at one end of said plates, a ram in said cylinder head, a platen carried by said ram between said plates and shiftable along' said plates back and forth by said ram, a plurality of links disposed between and hinged to said plates adjacent the other ends thereof and adjacent the forward and rearward edges of said plates, a

plates extending` in said links. the links hinged to the plates adju? cent one pair of corresponding edges oi said plates being shorter than the other links, the links along one pair of corresponding edges of said plates being connected together for simultaneous swinging movement, power actuated means connected to said connected links-for swinging the same about the pivoted connectionsto said plates to carry said head from a position, in which its pressing face faces said platen and is normal to the path of travel of said platen when the links all extend in directions endwise of said'plates,

into `a position in which said pressing face is at a substantially acute angle to its former position, and means for locking the unit formed of said links and head to-one of said plates while the head is in said pressing position. Y N

12.` In a shiftable head press, a pair. of par- 4alle] upright plates spaced apart and disposed side by side, a cylinder head connected between said plates at one end thereof, a rain mounted in said cylinder head and operable therein in` one direction `in the space between said plates, a platen disposed between said plates and connected to said ram for operation thereby in said one direction, a pressing head disposed between said plates and toward and from which said platen lis operable, and mounted between said plates for movement between a pressingpositio'n in which its face towards the platen is approximately normal to said one direction, and another position in which it has a substantial inclination to said one direction, a knock-out bar mounted in said platen for `independent movement in saidv platen in said `one direction, said plates having aperturesyin the zone traversed by said platen, through which the opposite ends of said knock-out bar extend, a casing disposed adjacent each oi' said apertures insaid plates, each casing having separate chambers therein opening in opposite directions which are parallel to said one direction, a piston in each of said chambers extending outwardly therefrom, one of said pistons bearing upon said knock-out bar and operable when forced in a direction outwardly of its chamber to force the knock-out bar toward said cylinder head and thereby retract said ram into said cylinder head, a member extending along each of said casing and having a portion engageable at one end beneath the adjacent projecting end of thel knock-out bar and at its other end connected to said other piston at the opposite end of said casing, whereby when said last named piston is forced outwardly, it shifts said member in said one direction and carries said'knock-outbar toward the exposed face` of said platen for ejection purposes; and means for selectively supplying actuating fluid to said chambers of said casings.

13. A shiftable head press comprising a frame, a cylinder head at one end of the frame, a piston in said cylinder head, a platen carried by the outer end of said piston and shifted back' and forth b v operation of said piston. a press head attached to said frame and shiftable from a pressing position in which its pressing face is normal to the direction of movement of said platen to a position in which the pressing face is more conveniently accessible, a source of actuating fluid under pressure. means connecting said source to said cylinder head. valve means ineluded in said connecting means and controlling the deiivery of fluid from said source to said cylinderhead and the escape of fluid from said cylinder head. said valve means having a valve element movable into one position in which it causes delivery of iiuid to said cylinder head and in another in which it releases iiuid from said cylinder head, a safety lock carried by'said frame l and engageable with said press head tolock the latter in pressing position and operable to re- `lease the head for movement out of said pressing position, and a connection -between said safety lock and said valve element operable to prevent movement of said valve element far enough to connect said source to said cylinder head until said safety lock is in locking position between the frame and press head.

14. A shiftable head press comprising a frame, a cylinder head at one'end of the frame, a piston in said cylinder head, a platen carried by the outer end of said piston and shiftedback and forth by operation of said piston, a press head attached to said frame and shiftable from a' zo pressing position in which its pressing face is normal to the direction of movement of said platen to a position in which the 4pressing face is more easily accessible, a source of actuating iluid under pressure, means connecting said source to said cylinder "head, valve means included in said connecting means and controllingthe delivery of fluid from said source to said cylinder head and the escape of uid from said cylinder head, said valve means having a valve element movable into one position in which it causes delivery of fluid to said cylinder head and in another in which it releases fluid from said cylinder head, a safety lock carried by said frame and engageable with said press head to lock the latter in pressing position and operable to release the head for movement out of said pressing position, a connection between said safety lock and said valve element operable to prevent movement of said valve element far enough to connect said source to said cylinder head until said safety lock is in locking position between the frame and press head, a switch operable by said head when said head is in pressing position, means for operating said valve element in a manner to cause delivery of l fluid from said source to said cylinder head and in turn controlled by sai switch and operable to *prevent movement of said valve element in a direction to cause delivery of fluid to said cylinder head until said switch is operated by said press W head, whereby operation of said valve element to cause delivery of fluidy to said cylinder head is impossible until said press head is substantially in pressing position and locked by said safety i lock.

15. In a press, a frame, a cylinder head having a rarn` mounted for4 advance and retraction, a pressure head shiftable on said frame into and out of pressing position, power actuated means for moving said pressure head into and out of pressing position, means including a pilot circuit for' controlling said power actuated means, and when effective causing a movement of said head into pressing position, a device including a single electromagnet for controlling said pilot circuit, a source of electric current, a controlling circuit for said electromagnet including Vtherein said source of current, a manually operated switch in said circuit and effective, when operated, to cause an operation of said power actuated means to move said head into pressing position, means rendered effective by said head when it reaches said pressing vposition to initiate an advance of said ram,

a switch responsive to an advance of said ram, Y

v*operated switch to also control said .electromagnet, said ram responsive switch being held in the same 'operated position throughout the advance of said ram until the ram returns to its starting position, whereby when said ram isaway from its retracted position-said circuit through said heldin its pressing positions, regardless of the position of said manually operated switch.

16, In a press,a frame, a cylinder head having a Vram mounted .formadvance and retraction, a Vpressurehead shiftable on said Vframe into and out o1' pressing position, power actuated means for moving said pressure head into and out of .pressing position, electromagnetically controlled Y means for in turn controlling said power actuated means,` an electric circuit through and controlling said electromagnetically kcontrolled means, a

Amanually operable switch in said electric circuit for selectively causing an operation. of Vsaid electronjlagneticallyY controlled means, and through it of said power-.actuated means, in a manner to vcau'se a k shiftingroi said head into pressing positiem-fand a press operated switch connected elec- ,tricallyin parallel across said manuallyy operable switch,-and opened and held openA by said ram whlletheram isretracted beyond a 4Selected Dosivtion and'T closed automatically'upon advance of saidram beyond said position and held closed unti1 returnoi said ram beyond said position inl a retraction movement.

17. In a-hydraulic press, a frame, a pressing d head on said frame, -a ram on said frame and operabletoward and from said-head', means includf ing a hydraulic circuit for operating said ram in a pressing stroke, valve means inV said circuit for controlling ,the advance and retraction of said Y ram, controlmeans having a control member yieldingly urged ,into a position in which it causes Y an operation of Vsaidvalve means into a condi- Ationto causegan advance oi' said ram, means responsive to the pressure on said ramin said circuit and operable automatically and repeatedly whenever thev pressure onsaid ram fluctuates above and below one selected pressure for forcing said control member out ctv-said position and causing aretraction of said ram, when the pressure on the ram exceeds said selected pressure and releasing said control member when said pressureon said ram falls below said selected pressure, thereby causing repeated operations of said .valve means and thereby .repeated-momentary, incomplete-minor retractionsand then readvances of said ram .alternately and means for automatically causing said valve means to remain in said condition in which lt causes an advance of said ram for all pressures on said ram, after a plurality of repeated, incompleteadvances and retractions. n Y

18, In a hydraulic press, a frame, a pressing head on said frame, a ram on said frame and operable toward and from said head, means including a hydraulic crcuit'for operating said ram Vin a pressing stroke, valve means in said circuit `electromagnet will cause said pressure head to be by causing Yrepeated operations of said valve Y means Yand thereby a plurality of repeated momentary, incomplete Vminor retractions and then readvancesV of said ramalternately and means vfor automatically removing said valve means from the control of said control member and causing said valve means to remain in said condition in which it causes an advance of said ram for all pressures on said ram, for a predetermined extent after a plurality of said incomplete advances and retnactions. Y

Y 19. Ina hydraulic press, a frame, a pressing head on said frame, a ram on said frame and operable toward and from said head, means including a hydraulic circuit for operating said ram in a pressing stroke, valve means insaid circuit for controlling the advance and retraction of said ram, control means havingY a control member yieldingly urged into a position in which lt causes an operation of said valve means into a condition to cause an advance of said ram, means responsive to the pressure on said ram in said circuit and operable automaticallyand repeatedly whenever the pressure on said ram fluctuate-s above and below one selected pressure for forcing said control member out of said position and causing a retraction of said ram, when the pressure on the ram exceeds said selected Ypressure and releasing-said control member when said pressure on said ram falls below said selected pressure, thereby causing repeated operations of said valve means and thereby a plurality of repeated momentary, incomplete minor retractions and then readvances of said ram alternately whenever pressure on said ram fluctuates above and below one selected pressure, means effective in all positions of the platen awayY from retracted position for removing said valve means from the controlof said Vpressure responsive means after said retractions andreadvances have continued i'or a predetermined extent, yand means for automatically causing a complet-e retraction of said ram a predetermined interval'ofV time after the'rst advance of said ram has been initiated and regardless of the rate of travel of said ram.

20, In a press, a frame, a head2 a ram, hydraulic power means operable to move said ram toward and from said head, valve means for controlling the movement of said ram by said power means, means for automatically controlling said valve means and yieldingly urged into a condition in which it causes an advance'of said ram, but operable out of said condition, lwhen said platen encounters one predetermined resistance to its advance, to cause a plurality of repeated slight .and incomplete retractions and readvances of said ram, and means including a counter operable to remove said valvermeans from control by said valve controlling means at the expiration of a'prederrnined plural number of said slight retractions and readvances.Y

2l. In a hydraulic press, a frame, a press head on said frame, a main cylinder, a ram in said cylinder operable toward and from said head, a source cf iluid under pressure, a conduit for connecting said source to said main cylinder, a pilot operated control valve in said conduit, an exhaust pipe connected to said valve, said valve being operable to connect said cylinder alternately to said source and to exhaust, a solenoid, a hydraulic circuit for operating said control valve controlled by said solenoid, a yieldingly closed control switch Y hydraulic circuit 'pressure in said main cylinder,

Y haust pipe connected responsive to pressure in said main cylinder, and opened by pressure and closed automatically when said pressure in said main cylinder fluctuates above and below a selected pressure, an electric circuit including said switch and said sole noid, and operable `through said solenoid and to operate said pilot controlled valve and connect said source to said main cylin derwhen said pressure is below said selected pressure, and to connect said main cylinder to exhaust when said pressure is above said selected pressure, and means for removing said electric circuit from the control oi said pressure responsive switch and holding it closed beginning a predetermined time after a pressing stroke of said ram is begun.

22, In a hydraulic press, a frame, a press head on said frame, a main cylinder, a ram in said' cylinder operable toward and from said head, a source of uid under pressure, a conduit for connecting said source tov said main cylinder, a pilot operated control valve in said conduit, an exhaust pipe connected to said valve, said valve being op erable to connect said cylinder alternately to said source and to exhaust, a solenoid, a hydraulic circuit for operating said control valve controlled by said solenoid, a control switch responsive to said main cylinder pressure rises above a selected pressure and closed automatically when said main cylinder pressure falls below said selected pressure, an electric circuitincluding said switch and said solenoidand operable through said solenoid and hydraulic circuit to operate said pilot controlled valve and connect said source to said main cylinderwhen said switch is closed, and to connect said main cylinder to exhaust when said switch is open, and means for shunting said control switch 'a predetermined time alter a pressing stroke yof said ram is begun.

23. In a hydraulic press, a on said frame, a main cylinder, a ram in said cylinder operable toward and `from said head, a source of iluid under pressure, a conduit for connecting said source to said main cylinder, a pilot operated control valve in said conduit, an exto said valve, said valve being operable to connect said cylinder alternately to said source and to exhaust, a solenoid, a hydraulic circuit for operating said control valve controlled by said solenoid, a yieldingly closed control switch responsive to pressure in said main cylinder. and opened and closed automatically when said pressure in said main cylinder fluctuates above and below one selected pressure, an electric circuit including said switch and said solenoid, and operable through said solenoid and hydraulic circuit to operate said pilot controlled valve and connect said source to said main cylinder when said pressure is below said selected pressure, and to connect said main cylinder to exhaust when said pressure is above said selected pressure, and means for removing said electric frame, a press head circuit iromithe control oi'V said pressure responsive switch and holding said circuit closed automatically after said main cylinder pressure has fiuctuated above and below said selected pressure a predetermined number and plurality of times.

24. In a hydraulic press, a frame. a press head and opened when on said irame, a main cylinder, a ram in said cylinder operable toward and from said head, a source of fluid under pressure, a conduit for conto said main cylinder, a pilot operated control valve in said conduit, an exhaust pipe connected to said valve, said valve being operable to connect said cylinder alternately to said source and to exhaustpa solenoid, a hydraulic circuit for operating said control valve controlled by said solenoid, a control switch responsive to pressure in said main cylinder, and automatically opened and closed when said pressure in` said main cylinder iiuctuates above and below a selected pressure, an electric circuit including said switch and said solenoid, and operable through said solenoid and hydraulic circuit to operate saidpilot controlled valve and connect said source to said main cylinder when said pressure is below said selected pressure, and to connect said main cylinder to exhaust when said pressure is above said selected pressure, and means for removing said electric circuit from the control of said pressure responsive switch andV causing said valve to remain in a condition to connect said source to said main cylinder, hydraulic means said head on said links, an electric circuit controlling said hydraulic means and having a starting switch, said circuit and the hydraulic means controlled thereby being operable to move said head into said pressing position when said switch is closed and to tilt said head when said starting switch is open, and means for automatically shunting said starting switch while said ram is out of Aits retracted position.

25. In a hydraulic press, a frame, a press head on said frame, a main cylinder, a ram in said cylinder operable toward and from said head,

means for moving said head on said frame into solenoid, a contro1 switch yieldingly urged into one position and responsive to pressure in said main cylinder, and opened and closed automatically when said pressure in said main cylinder fiuctuates above and below one selected pressure. an electric circuit including said switch and said solenoid, and operable automatically through said solenoid and hydraulic circuit to operate said pilot controlled valve and connect said source to said main cylinder when said pressure is below said selected pressure, and to connect said main cylinder to exhaust when said pressure is above said selected pressure, means for removing said electric circuit from the control of said pressure responsive switch and causing said valve to connect said source to said main cylinder for a predetermined time after a pressing stroke o1 said ram is begun, and switch means responsive to the position of said head for automatically opening and maintaining open said circuit through said solenoid while said press head is out of pressing position. A

THOMAS F, STACY.

for swinging

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