US1659157A - Manually-operated press - Google Patents

Description

Feb. 14, 1928.

' 1,659,157 T. c. PROUTY.

MANUALLY OPERATED PRESS Filed March 25, 1926 2 Sheets-Sheet J fi ybvrz I V/ k 0 a YINVENTOR.

A TTORNEYI Feb. 14, 1928.

T. C. PRQUTY MANUALLY OPERATED PRESS Filed March 25. 1926 2 Sheets-Sheet 73 IN V EN TOR. W

J i U 4%.. 9% l5 7 g? 0 A TTORNEY fi l Patented Felon l t, lgfiu an il THEODORE C. PROUTY, 0F HERMGfi-A BEACH, CALIFORNIA, ASSIGNOB TO AMERICAN ENCAUSTIC TILING- COMPANY, LTD, 013 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

MANUALLY-OPERATED PRESS.

The object of the invention described and claimed herein is the provision of means whereby the movable member of the hydraulic press may be moved through that part of its poweiustroke in which there 1s no resistance from the material or ob1ect 1n the press and through all or substantially all of the return stroke by the direct application of mechanical as distinguished from hydraulic torce thereto, force being transmitted to the head through the liquid confined between the small and large plungers only during the relatively small part of the power stroke during which the movement of the pressure member is opposed by the resistance of the material or object in the press. In the operation of any press a large part of the movement is that necessary to separate the dies sutliciently to permit convenient and rapid insertion of the work in and its removal from the press. The only part of the movement of the press requiring the exertion of great force is that which takes place on the power stroke after contact is established between the work and the movable die. During all the remainder of the movement the only force necessary is that required to overcome the frictional and other internal resistance of the mechanism. In a hydraulic press consisting simply of small and large cylinders with their plungcrs the entire movement of the press is effected by the expulsion of liquid from the small into the large cylinders, thus slowing down the idle part of the movement where little force is required to an extent that greatly restricts the number of pressing operations that can be performed in a given time. Specifically the object of the invention described herein is to effect all of the movement of the press rapidly and with the expenditure of little power with the exception of the relatively brief interval when pres sure is being exerted on the material or ob ject in the press. The operation of a hydraulic press may be speeded up by the use of a high pressure accumulator for the pressure fluid but this method is wasteful inasmuch as it involves the use of the high pressure fluid throughout the entire extent of both the power and return movement, whereas high pressure is necessary only during the short period during which the press is acting on the work. The use ot'a low pressure accumulator for the idle part of the movement and a. high pressure accumulator tor the interval during which the actual work is being performed obviates the excessive waste incident to the method last mentioned but increases the con'iplexity of the mechanism by reason of the necessity of having two accumulators together with means for keeping them properly charged and means for operating the valves connecting the accumulators with the power cylinders. By the invention herein described and claimed the movement of the press is etl'ected rapidly and without great expenditure of power except during the time when pressure is being exerted on the work, and it is only during this last named brief interval that the press functions strictly as a hydraulic press.

In the drawings- Figure 1 is a perspective view of a press embodying the invention, and adapted for use in the dry-mold ceramic process, parts of the structure being broken away to show the interior construction.

Figure 2 is a detached view of a slide or wiper used for filling the mold with the powdered mixture which the press illustrated is arranged to compress in a mold.

Figure 3 is a view of the hand-wheel by which the press is operated, this part being omitted from Figure 1 in order not to obstruct the view of other parts of the mechanism.

Figure 4 is a detached slightly enlarged view of a rack-bar which is engaged by a pinion on the shaft of the hand Wheel.

Figure 5 is an enlarged view of the small plunger, i. e., the upper one just beneath the rack-bar.

Figure 6 is a detail View of the upper part of the casing and ot a frictionally operated valve and valve rod.

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Figure 7 is a detail view of the large plunger and certain connected and co-operating parts.

Figure 8 is. a. perspective view of a modified form of the press.

Figure 9 is a detail view of a modified form of valve to be used in the structure shown in Figure 8.

In the press illustrated in Figures 1 to 7 rotation of the handwheel 1. which together with pinion 16 is fixed to shaft 2, impart-s sleeve 8 and th movement to rack-bar 3. The lower end of rack-bar 3 is reduced in diameter and tapped at 17, to receive a screw-threaded stem on the upper end of bar 6. The ends of rackbar 3 and bar 6 are brought together in a central opening in plunger 5 and screwed together to clamp the plunger between opposing flanges on members 3 and 6, thus making a single rigid member of the rackbar 3, plunger 5, and bar 6. .Plunger 5 0perates in the smaller part 13 of the cylinder of the press. Operating in the larger part 14 ofthe cylinder is the large plunger 7.

Plunger -7 is provided'with a central aperture 20. Surrounding aperture 20 and screw-threaded intothe lower side of plunger 7 is a sleeve 8 which is closed at the bottom end where the pressure head 10 of the press is fixed to it. Within the sleeve 8 is a helical spring 9, the lower end of which abuts against the closed lower end of the e upper, end against a shoulder 19 formed on the rod 6. The rod 6 pro jects downwardly into the sleeve 8 part of the length thereof, leaving space, however, between the lower end of rod 6 and the bottom of sleeve 8 to permit downward movement of the rod relative to the sleeve of an extent suflicient for the purpose hereinafter described. The initial tension of spring 9 is sufficient to transmit from rod 6 to sleeve 8 and attached pressure head 10 and plunger 7 the force necessary to move the pressure head 10 before the die 11 contacts with the object or material in the press, and hence during this part of the movement the spring 9 is not compressed.

The oil or other liquid through which the pressure" is transmitted when the press is functioning hydraulically is supplied from the reservoir 22 which is in free communicatlon with the cylindrical casing 21. An opening 23 extending through the plunger 5 establishes communication from the casing.

21 to the space between pl'ungers 5 and 7 in the large and small cylinders 13. 14. Communication through the opening 23 is controlled by a valve 24, the stem 25 of which extends upwardly passing freely through a groove in the side of rack-bar 3 opposite the teeth thereon. The upper end of valve rod 25 passes through a sleeve 26 which projects upwardly from the casing spring friction member 28 is fixed to stem 25. This friction member may conveniently consist of leaf springs carried by a tubular member adjustably secured on stem 25. A shoulder 29 (shown in dotted lines in Figure 5) projecting'from rod 6 just below plunger 5 limits the downward movement of valve 24 relative to the plunger.

The movement of valve 24 relative to plung-' er 5 is thus confined to the distance between the position of the valve when seated and its position when in contact with shoulder 29.

Assuming that the plungers are at their upward limit of movement as shown in Figure 1, that the valve 24 is open, i. e. lowered relative to plunger 5, and that oil or other liquid fills the space between the plungers ,5 and 7 and the casing 25 and reservoir 22, then rotation of the hand-wheel in clockwise direction will move rack-bar 3 downward. and with it plunger 5 and rod 6, parts 3, 5, and 6 being, as above stated, rigidly connected together. At this time the die 11 is free of the object or material in the press, its uppermost position being sufliciently high to afford ample clearance for the convenient insertion of the work in the press and its removal therefrom. The first part of the downward movement of the movable parts of the press is, therefore, opposed only by the friction and other resistance of the mechanism, and the downward movement of rod 6 is transmitted through shoulder 19, and spring 9 to the bottom of sleeve 8 which is connected to and in elfect a part of plunger 7, this action taking place without compression of spring 9, owing to its initial tension being sufficiently high to resist the force transmitted through it in this part of the operation of the press. The downward movement of the two plungers just described has the effect of increasing the volume of the space between the plungers within the cylinders, and, valve 24 being at this time open, oil flows through the opening 23 in plunger 5 thus filling the increased space between lungers 5 and 7. The friction member 28 is adjustable longitudinally of rod 25 and is so set that at the time, or just before the time, when the die 11 contacts with the object in the press the friction member enters the sleeve 26, whereupon its frictional engagement with the inside surface of the sleeve arrests the downward movement of valve 24. Normally gravity causes the valve 24 with its stem 25 to fall to its lowermost position, in which position the valve rests upon the shoulder 24, the relation of these parts being shown in Figure 5, leaving the opening 23 unobstructed. The downward movement of valve24 being arrested and that of plunger 5 continuing the valve seats in openin 23 thus confining the oil in the cylinders lietween plungers 5 and 7. After valve 24 is seated further downward movement of plunger 5 carries the valve with it, this further movement of the valve taking place against the frictional resistance between friction member 28 and the inside of sleeve 26. Upon the closing of valve 24 the mechanism begins to function as ahydraulic press, continued rotation of the hand-wheel and downward movement of plunger 5 forcing oil from the small cylinder 13 into the large cylinder 14 and imparting'movement to the large plunger 7 inversely proportionate to the cross-sectional areas of the two ill) cylinders. In this part of the movement the travel of the small plunger 5 is greater than that of the large plunger, this difierential movement causing and being permitted by compression of spring 9 in sleeve 8. The movement of plunger 5 after valve 24 is closed as above described is sutlicient to perform the necessary operation upon the object in the press, and this movement after the closing of valve 24 is permitted by compression of spring 9.

When the rotation of the hand-wheel l is reversed to raise the die 11 the first effect of the upward movement of plunger 5 is to open valve 24, the opening of the valve being caused by the fact that the friction between member 28 on stem 25 and the inside of sleeve 26 holds the valve 24 stationary while the plunger 5 is moving upwardly. After plunger 5 has moved a short distance the shoulder 29 shown in Figure 5, contacts with valve 24 and carries it upward but leaving the valve open. A weight 27 is slidably mounted on valve stem 25 above friction member 28. In case the weight of valve 24 and its stem 25 is not sufficient to reliably hold the valve down in its open position after member 28 has risen above sleeve 26 the added weight of member 27, which is carried by the valve stem 25 when member 28 rises above the top of sleeve 26, will be suflicient to prevent valve 24 from being closed by the upward rush of oil through opening 23 During the first part of the upward movement of plunger 5 the spring 9 expands until shoulder 19 is stopped by Contact with the under side of plunger 7, and during this interval substantially no movement is communicated to plunger 7. This first upward movement of plunger 5, independently of plunger 7 increases the volume of the space between the plungers thereby causing oil to be drawn through the open valve 24 from the casing 21 into the space between the plungers. After the independent movement of plunger 5 has been arrested by contact of shoulder 19 with the under side of plunger 7 the further upward movement of plunger 5 carries plunger 7 with it. This simultaneous and equal movement of plungers 5 and 7 causes a decrease of the space between the plungers and valve 24 still being open oil flows through opening 25 from the space between the plungers upwards into casing 21, this flow being the reverse of that just preceding when plunger 5 was moving upward- 1y independent of plunger 7.. When plunger 5 has been raised to its uppermost position, the position shown in Figure 1, the valve 24 is still open and all of the parts are in position for the beginning of the cycle of operations above described.

In the form of the press above described the time at which the press begins to function hydraulically is governed by the position of the friction member 28, and to have the hydraulic action begin at the time the die contacts with the object in the press it is necessary to adjust the position ot member 28 so that its retardation by the sleeve 26 will close valve 24 just as the die contacts with the object in the press or substantially atthat time. Figure 8 is an illustration ot'. a form of press in which the hydraulic action begins automatically when the die encounters sufficient resistance from its action on the object in the press.

In the press shown in Figure 8 the small plunger 40 is a ries of rack teeth extending longitudinally on one side of its outer surface. A helical spring 41 inside of the tubular plunger abuts at its upper end against a plug 42 which is screw-threaded into the upper end of the bore of the tube. A central opening 43 through plug 42 establishes free passage for oil between the reservoir 44 and the interior of the tubular plunger. lhe lower end of spring 41 abuts against a head 47 formed on the upper end of a stem 45 which projects upwardly from the large plunger 46. The bore of the tubular plunger 40 is restricted at its lower part forming an annular shoulder which coacts with the shoulder on the lower side of head 47 to limit the movement of small plunger 40 and large plunger 46 away from each other. The. plunger member 40 is provided at its lower end with a packing 48. An axial opening extends downward from the top of stem 45 to a point which when the plungers are at the upper limit of their movement is below the lower end of plunger 40, and a traverse port 49 extends from the opening 50 to the outer side of stem 45 at a point just below the lower end of plunger 40 when the parts are in the elevated position mentioned. As in the case of the form of the press shown in Figures 1'to'7 the initial tension of spring 41 in the press shown in Figure 8 is'sufiicicnt to transmit without compression the force necessary to move the large plunger and die downward before the die contacts with the object in the press. The added resistance encountered when the die contacts with the objectin the press causes the small plunger tubular member with a se- 40 to move downward relative to the large plunger 46 with compression of spring 41, the purpose of spring 41 being to prevent relative movement of the two plungers before the resistance of the object in the press is encountered and to permit such relative movement afterwards. While plungers 40 and 46 are moving down together they are in the relative position shown in Figure 8, and during this period oil flows through the bore 50 and port 49 thus keeping the enlarging space bet-ween the large and small plungers filled. When the die 51 contacts with and encounters sufiicient resistance from the object in the press the tension of spring 41 is not suflicien't to resist the force actin between the small and large plungers, and t 1e small plunger begins to move down relative to the large plunger. This has the effect of immediately closing port 49 thus confining the body of oil between the two plungers and thereafter the press functions hydraulically. For the return upward movement the operator rotates the pinion clockwise as viewed in the drawing. During the first part of the up-stroke of the small plunger and until port 49 is uncovered the oil between the plungers is confined and the large plunger moves upward with the small one at a rate inversely proportional to their areas. Port 49 becomes completely uncovered at the time the shoulder at the bottom of the large bore in the small plunger engages the head 47 on the stem 45 projecting upwardly from the large plunger. The press then ceases to act'hydraulically and the force applied to the small plunger is transmitted directly to the large plunger and they both move upward together at the same rate. This simultaneous and equal upward movement of the two plungers decreases the volume of the space between them and oil flows upward through the port 49 and bore 50 until the upper limit of movement is reached, whereupon the mechanism is in position for a repetition of the cycle above described.

In Figure 9 I show a modified form of valve for controlling the flow of oil into and out of the space between the plungers. In the modified structure the stem 45 projectmg upward from the large plunger is of less diameter than the opening through the end of the small plunger thus leaving an annular space 70 for the passage of oil or the liquld used in the press. The under side of the head 47 is recessed at71 leaving only a. peripheral lip 72 to contact with the shoulder 73 at the bottom of the large bore in small plunger 40. Openings 74 afl'ord communication between the interior of the small plunger and the space 71 and thence through space 70 to the valve 7 5 which controls communication with the space between the small and large plungers. Valve 75 frictionally engages stem 45 and remains in the same position relative to stem 45 except when moved by the relative movement of the small plunger 40 and stem 45, the latter being fixed to or a part of the large plunger. Assuming that both plungers are in their elevated position and the valve 75 lowered from its seat 76, i. e. in open position as shown in Figure 9, upon the beginning of the downward movement of small plunger 40' relative to stem 45 valve seat 76 will approach valve 7 5 and close it, this valve closing action being accomplished by a very slight relative movement of the parts between the mentioned. A packing 77 serves to prevent the passage of oil between valve 75 and stem 45. After the closing of valve 75 by the action referred .to the press. functions hydraulically until the completion of the power stroke, the operation at this time being identical with that of the structure shown in Figure 8. Upon the commencement of the return, upward, movement of plunger 40, the valve 75 remains stationary )y reason of its frictional engagement with stem 45 and valve 75 is therefore opened immediately upon the commencement of the return, upward, stroke. Depending from the end of small plunger 40 is a cage 78 consisting of several bars having their lower ends inturned at 79 to underlie the edge of valve 75. After the small plunger 40 has moved upward suflicicntly to fully open valve 75 the bottom of the cage formed by the parts 79 engages the valve and carries it upward with plunger 50, leaving the valve open. By means of the action described there is free communication between space plungers and the interior of plunger 40 from the moment the return, upward stroke commences, and hence there is substantially no upward movement of the large plunger until the shoulder 73 of the small plunger 40 engages the downwardly projecting rim 72 on the under side of head 47and thereafter the two plunger-s move together at the same rate. Valve 75 being open throughout the up-stroke there is a flow of oil downwardly past valve 75 while plunger 40 is moving independently of the large plunger and a flow of oil in the opposite directlon at the latter end of the up stroke when both plungers are moving upwar ly together at the same rate. In this respect the use in the apparatus shown in Figure 8 of the valve shown in Figure 0 results in an operation on the up-stroke similar to that of the apparatus shown in Figure 1-.

The lower end of the large cylinder is closed in both of the presses illustrated, the end casing 15 in Figure 1 and 52 in Figure 8 serving to catch the oil that leaks past the large plunger, and the drain pipes 53 and 54 respectively carry oft the oil leakage. Packing at 55. best seen 1n Figure 8, prevents escape of oil at a point where it would reach the dies and the object in the press.

The press shown in Figure 1 is provided with a hopper 32 to contain the powdered material used in the dry-mold ceramic process, and the slide 31 is provided with a bail 62 whereby the. operator moves it forward and back. The forward movement carries the powder contained in the opening in the slide to the recessed lower die 30 and deposits it thereon. The treadle and mechanism connected thereto are the means for ejecting the pressed material from the lower die. The pipes 63 and 54 are steam :onnections for heating the dies.

I claim: e

1. In a device of the class described, relatively small and large cylinders intercomnnmicating and small and large plungers operable therein, means related to the position of said plungers for governing flow of liquid between said cylinders, a connecting member extending a limited relative movement of said plungers, and resilient means normally holding said plungers in their most Widely separated position.

2. In a device of the class described, relatively small and large cylinders and small and large plungers operable therein, connecting members extending between and permitting a limited relative movement of said plungers, resilient means normally holding said plungers in their most widely separated position, means permitting free ingress and egress of liquid to and from the space between said plungers when said plungers are in their most widely separated position and for confining liquid between said plungers when said small plunger moves relatively to and toward said large plunger.

3. In a device of the class described, large and small cylinders and large and small plungers operable therein, telescoping members connecting said plungers, a spring normall acting to extend said telescopic connection, a valve controlling an opening communicating with the space within said cylinders between said plungers, means for maintaining said valve in open position when said telescopic connection is fully extended and closed when said telescoping members are approaching each other.

I; In a device of the class described, large and small cylinders and large and small plungers operable therein, telescoping members connecting said plungers, a spring 'norbetween and permitting mally acting to extend said telescoping connection, a valve controlling an opening communicating with the space within said cylinders between said plungers, means for maintaining said valve in open when said telescopic connection is fully extended, closed when said telescoping members are approaching each other and open when said telescoping members are receding from each other.

5. In a device of the class described, large and small cylinders and large and small plungers operable therein, telescoping members connecting said plungers, a spring normally acting to extend said telescopic connection, said small plunger having a por extending therethrough, a valve in said port and opening toward the space between said plungers, a stem connected to said valve, and projecting upwardly therefrom, a stationary friction member and a coacting friction member mounted on said stem.

6. In a device of the class described, large and small cylinders and large and small plungers operable therein, telescoping members connecting said plungers, a spring normally acting to extend said telescopic connection, a valve controlling an opening communicating with the space within said cylinders between said plungers, a stationary friction member and a co-acting friction member connected to said valve, said triction members being positioned to engage each other after a predetermined amount movement of said plungers in one direction and thereby close said valve, said friction members remaining in engagement during the remainder of the movement of said plungers in the direction mentioned and operating t open said valve upon reversal of the direction of movement of said plungers.

In testimony whereof, I have subscribed my name.

TIIEODORE C. PROU'IY.

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