US2948071A

US2948071A - Hydraulic laundry press

Info

Publication number: US2948071A
Application number: US671756A
Authority: US
Inventors: Edmund N Neckel; Leo B Wessel
Original assignee: American Laundry Machinery Co
Current assignee: American Laundry Machinery Co
Priority date: 1957-07-15
Filing date: 1957-07-15
Publication date: 1960-08-09
Anticipated expiration: 1977-08-09

Description

Aug. 9, 1960 E. N. NECKEL ETAL 2,

HYDRAULIC LAUNDRY PRESS 2 Sheets-Sheet].

Filed July 15, 1957 m illn JNVENTOR. Fond/v0 M NA'C/(El- LEO J. WESJ'IL gyrramvsya Aug. 9, 1960 E. N. NECKEL ETAL HYDRAULIC LAUNDRY PRESS Filed July 15, 1957 2 Sheets-Sheet 2 Eonuwo A. NIC EL L50 5. We'ssn HTTQIPNEYJ' United States Patent HYDRAULIC LAUNDRY PRESS Edmund N. Neckel and Leo B. Wessel, Cincinnati, Ohio,

assignors to The American Laundry Machinery Company, Cincinnati, Ohio, a corporation of Ohio Filed July 15, 1957, Ser. No. 671,756 r 19 Claims. (Cl. 38-41) By way of example, and not of limitation, our invention will be described in connection with a press having a fixed bed or buck, the head being mounted on the end of a lever arm of the first class. -Two sources of motive power are provided for operation of the head lever. One source consists of a motor for moving the lever into or immediately approaching operative contact with the buck. A second source comprises a booster ram, and motive power therefor, including a hydraulic piston and means for its operation, whereby intensified pressure may be applied to the work in the final increment of pressing movement of the head lever.

An object of the invention it is to provide novel and improved operating means for the booster pressure operation. 1

A further object of the invention is to provide a booster pressure motor adapted for the utilization of air power in cooperation with hydraulic power, there being in lineal axial arrangement a hydraulic piston movable in its cylinder and an air piston having an operating ram movable into the hydraulic cylinder toincrease the pressure therein at a preselected stage of the operation.

A further object of the invention is to provide a booster pressure device of the type defined in the last preceding paragraph and adapted to apply a materiallyincreased pressure over that securable in generally related presse of the prior art. 1 a

A further object of the invention is to provide, in a press of the character just characterized, a completely closed, liquid filled hydraulic pressure system, without.

air spaces, in which substantially all movement of the hydraulic piston .is permitted by displacement of the liquid from one side of the hydraulic piston to the. other.

A further object of the invention is to provide a hydraulic pressure system of the type hereinabove characterized, and wherein aconfiningwall portion of the hydraulic chamber is yieldable to permit minor volume changes in the confining space. p

A further object of the invention is to provide a head lever operating system including a first motor having an operating rod connected to the head lever at a point intermediate the lever ends and a booster pressure rod connected to the head lever at the-end remote from the head.

A furth er object of the invention is to provide a press of the character described in the last preceding paragraph and wherein the booster pressure motor is pivotally connected at a first point fixed with respect to the frame,

' the head lever is likewise pivoted at a second point fixed with respect to the frame, and the operating rod from the "ice booster pressure motor is connected to the head lever at a third pivot point which, during operation of the head lever, moves across center with respect to the first and second pivot points. i I

A further object of the invention is to provide a press as defined in the last preceding paragraph, and wherein the booster motor is constructed to provide a single snubbing means elfective both at the beginning and end of head lever movement.

Other objects and advantages will be apparentfrom a study of the following description of one embodiment of the invention, in conjunction with the following drawings, in which: i

Fig. 1 is an elevational view, partially structural and partially schematic, showing a laundry press with fluid power motive means, and air pressure supply piping.

Fig. 2 is a sectional view taken axially through the booster unit.

Fig. 3 is a view taken on the line 3-3 of Fig. 2.

Fig. 4 is a sectional view taken on the line 4-4 Fig. 3. i

Fig. 5 is a view taken on the line 55 of Fig. 3, but showing only a fragmentary portion of the booster unit.

Referring first to Fig. l, the head lever 10 is pivotally mounted at 11 in side frame 12. The booster unit, which comprises both an air piston and a hydraulic piston, is pivotally mounted in the side frame members at 14, in the same vertical plane with the head lever pivot 11 and in a vertical line therein. The head lever is curved, and at one end has a pivot connection 15 with piston rod 16. This pivot connection 15 has an over-center movement with respect to pivots 11 and 14. When the press is open, as shown in full line, the pivot 15 is to the right of the center line, and when the press is closed, as fragmentarily indicated in broken line, the pivot 15 is to the left of the center line 11--14.

The head is moved to closed or open position by the primary head operating air motor 17 which has a fixed pivotal connection 18 on frame 12. Its operating rod 20 is pivoted to lever 10 at an intermediate pivot point 19, spaced from each end of the lever 10. l

' It will be apparent that as the head lever 10 swings clockwise to head-closing position the swing of pivot pin 15 causes rod 16 to move its piston 16a into the hydraulic cylinder, the structure being more fully described in connection with the description of Fig. 2. As the head 21 approaches contact with the buck 22 heavy pressure is created by movement of a ram 23 into a body of hydraulic fluid below piston 16a. Ram 23 is integral with ram piston 23a. At the half-closed point, with pivot points 11, 14 and 15 in a vertical line, piston 16a is at the bottom of its stroke as shown in Fig. 2, now to be described.

As shown in Fig. 2 a heavy-walled cylinder 24ihas a base 25 and at its upper end an intermediate head casting 26. The head, the base, and the Walls are 'tied to gether by four bolts 27 which extend through holes in Cylinder 24 has a pair of gudgeons 24a near its bottom for pivotal mounting in the frame at 14.

The upper face of head casting 26 has a circular recess into which is nested a flanged end piece 29 which receives on the flange the lower end of hydraulic cylinder 28. The intermediate head 26 and the end of the hydraulic cylinder have a coaxial bore through which ram 23 may pass upwardly into the hydraulic cylinder 28. A flexible sealing collar 30 extends upwardly within the bore.

Cylinder 28 has at its upper end a head casting 31. The

three

members

26, 28 and 31, defining the hydraulic cyliuder, are tied together by stud rods 32 and nuts 32a.

Coaxial with cylinder 28 and radially spaced outwardly I therefrom is a cylindrical flexible tube 33, secured at its respective ends to intermediate head 26 and top end head 31. As will appear the annular space 35 thus provided constitutes a reservoir and by-pass passage for the hydraulic fluid displaced by movement of piston 16a. This fluid fills all space Within the cylinder 28, in the annular reservoir 35, and'in all communicating passages. It provides a true closed system free of air and sealed off from atmosphere. The significance of a true closed system is that in the development of exceptionally high booster pressures, as here, the characteristics of the operation are rendered erratic by any possible air pockets in the liquid since air is readily compressible, while in a completely liquid-filled system the liquid is substantially incompressible. In the present system the liquid-carrying space is variable, dependent on Whether the ram 23 is extended or retracted, and on what extent of piston rod 16 is in the chamber in cylinder 28, but variation of internal volume by the amount of liquid displaced by ram 23 is compensated for by slight flexure of resilient tube 33. The liquid-containing space is filled by way of

plug openings

36 and 37, air being vented at the same time.

A slide bearing cap 38 is secured to casting 31 by two cap screws 39, and is fitted with a liquid seal 40 and a wiper seal 41. Other suitable seals are employed at locations S. A vent bore 42 runs through to a groove bemember 31, and portion 16c lies inside of bore 31a with a small amount of clearance. Compressed air is holding booster or ram piston 2.3a retracted, coming from air line 45, slide valve 46,

lines

47, 48 and source. All

other valves are closed. Springs 49 are holding the press open.

The operator presses the usual horizontally-spaced pair of control buttons to operate valves 50, 51. Air from

lines

52, 48 is admitted through valve 50' to line 53, thence through valve 51 and line 54 to the diaphragm actuator 55 of larger master valve 56, opening this valve. Air from line 48 goes through the valve to line 57 and inlet 17a of primary air motor.

As the head lever moves down through the first half of its swing, hydraulic piston rod 16 is pushed down. Recall that liquid completely fills the space above and below piston 16a. During this downward travel of piston 16a the liquid flows freely through the ball check valve 58. The flow path, starting below the piston, is down through bore 29a, collar 39, ports 59 in casting 26, up through reservoir, through ports '60 in top casting, and

doWn through the check valve 58, and also through annular space 3111 after part 160 has withdrawn therefrom. A small amount passes by needle valve 61. As the unit goes over center and the piston begins to be pulled upward the liquid flow path is reversed, and check valve 58 closes. However, there is as yet no appreciable snubbing, the passage 31a allowing substantial flow.

When the press head is a few inches from the buck, part 160 of the piston rod enters bore 31a, closing this passageway except for a very slight clearance. Flow now must be through adjustable needle valve 61, so that the press head is abruptly decelerated. When the press reaches the safe closed position, the chest a little short of contact with the buck, piston 20a of the primary air motor passes a port 17b, admitting air by line 62 to the left hand servo-motor or actuator chamber of slide valve "'46. This shifts the valve to the right, putting line 63 in communication with air inlet line 47, and at the same t1me cutting off the air to line 45 which is then vented through port 46a. A similar port'46b vents line 63 when the valve 'is'in the'otherposition, as shown.

The ram 23 is now advanced by ram piston 23a. As it goes through collar seal 30, it acts to seal oif the liquid within cylinder 28 from the rest of the system. Continued advancement of the ram into the body of liquid below piston 16:: produces a greatly magnified unit pressure according to the well-known hydraulic pressure principle. The press elements are so related that, with the head in full pressure, the piston will be almost at the limit of its stroke. Incidentally, it can be seen that the liquid which the piston forces up during the final high pressure part of the stroke cannot return in the normal path, due to closure at seal 30, but this quantity is volumetrically accommodated by the flexible reservoir.

The operator releases the two-hand control valves 50, 51, when the high pressure unit operates. This allows master valve 56 to close, cutting off air to cylinder 17. It

might be mentioned at this point that motor 17, beingsingle-acting, is vented at the top end, so there is no risk of premature operation of slide valve 46.

Operation of release valve 64 now admits air from line 52 to line 65 actuating the right hand piston of slide valve 46 to shift the valve back to original position. This reverses the air to the booster air motor and retracts its ram piston 23a, whereupon the liquid passage at 30 is reopened, allowing hydraulic piston 16a to descend and the press to be opened by springs'49. 1

The over-center movement of our power unit has, among other advantages, the fact that a snubbing means is needed only at one end of the booster cylinder since the hydraulic piston has its full-open and full-closed station atv the same location. The over-center arrangement also permits a shorter power cylinder.

What we claim is:

1. In a laundry press of the type wherein the work is disposed between two pressing members, one of which members is movable into operative contact with the other, means for effecting such contact including a hydraulic cylinder, a first piston in said hydraulic cylinder, means operatively connecting said first piston with said movable pressing member, an air cylinder in axial registry with said hydraulic cylinder, a second piston in said air cylinder, a ram operably carried by said second piston and having a portion extendable axially into said hydraulic cylinder whereby, when air is admitted behind said second piston in said air cylinder, the extendable portion of said ram is advanced to exert hydrostatic pressure upon the first said piston.

2. In a laundry press of the type wherein the work is disposed between two pressing members one of which is movable towards operative contact with the other, means for applying working pressure to said movable member including a hydraulic cylinder, a first piston movable in said hydraulic cylinder, means operatively connecting said first piston and said movable pressing member, said first piston having a working face, pressure against which drives said movable pressing member toward contact with the other pressing member, a hydraulic fluid in said hydraulic cylinder on each side of said piston, by-pass passage means externally of said hydraulic cylinder and in communication with each end of said hydraulic cylinder whereby to permit displacement of liquid through said passage upon movement of said first piston, an air cylinder in axial registry with said hydraulic cylinder, a second piston in said air cylinder, a ram carried by said second piston and having a portion extendable axially into said hydraulic cylinder whereby when said ram is advanced it applies hydrostatic pressure against said working face of said first piston.

3. Apparatus as=defined in claim 2 wherein said bypass passage is provided with a yieldable wall portion to compensate only-for volumetric changes in the liquid containing capacity of said hydraulic cylinder and-said by-pass passage by ram displacement upon movement of ;said ramportion within said hydraulic cylinder, there anew passage,.and adapted to be closed by advance movement of said ram.

4. In a laundry press of the type wherein the work is disposed between two pressing members one of which is movable towards operative contact with the other, means for applying intensified working pressure to said movable member including a pressure cylinder unit having an intermediate cylinder head whereby to divide said unit into two pressure cylinders consisting of a hydraulic cylinderand an air cylinder inaxial alignment, a first piston movable in said hydraulic cylinder, means operatively connecting said first piston and said movable pressing member, a second piston in said air cylinder, an aperture in said intermediate cylinder head, a ram carried by said second piston and having a portion extendable through said aperture into said hydraulic cylinder, a hydraulic liquid in said hydraulic cylinder on both sides of said first piston whereby when said ram is advanced by air pressure application in ram'extending direction in said air cylinder, hydrostatic pressure is applied to said first piston to effect working contact between said pressing members.

5. Apparatus as defined in claim 4 wherein a by-pass passage means has its ends in communication respectively with said hydraulic cylinder ends, whereby to permit displacement of hydraulic fluid from one end of said cylinder to the other upon movement of said first piston.

6. Apparatus as defined in claim 5 wherein check valve means is disposed in said by-pass passage to permit liquid displacement in one direction only past said check valve.

7. Apparatus as defined in claim 6 wherein said by-pass passage means is provided with a flexible wall portion to compensate only for volumetric changes in the liquidcontaining capacity of said hydraulic cylinder and said by-pass passage means by ram displacement upon movement of said ram portion in said hydraulic cylinder, there being port means constituting a part of said by-pass passage, and adapted to be closed by advance movement of said ram.

8. Apparatus as defined in claim 5 wherein means is provided for restraining by-pass flow through said by-pass passage when said movable member approaches pressing contact with said fixed member whereby to snub approach movement of said members at the time of mutual contact.

9. A laundry press of the character described having a frame, a movable pressing member and a fixed pressing member, a lever having said movable pressing member attached to one end thereof, said lever being pivotally supported on said frame at a first pivot point intermediate the ends of said lever, a power cylinder unit pivotally connected to the frame at a second pivot point, said unit having a hydraulic cylinder and an air cylinder in axial alignment, a first piston in said hydraulic cylinder having a piston rod pivotally connected to said lever at a third pivot point on the lever end remote from i said pressing member, said third pivot point being disposed to swing over-center across the line between said first and second pivot points upon movement of said.

said ram is advanced by air pressure application in ramextending direction in said air cylinder, hydrostatic pressure is applied to said first piston to efiect applica tion of working pressure between said pressing members.

10. Apparatus as defined in claim 9 wherein by-pass passage means has its ends in communication respectively 1 with said hydraulic cylinder ends, whereby to permit displacement of hydraulic fluid from one end of said cylinder to the other upon movement of said first piston.

11. Apparatus as defined in claim 10 wherein check valve means is disposed in said by-pass passage to permit liquid displacement in one direction only past said check valve.

12. Apparatus as defined in claim 11 wherein said by-pass passenger means is provided with a flexible wall portion to compensate only for volumetric changes in the liquid containing capacity of said hydraulic cylinder and said by-pass passage means by ram displacement upon movement of said ram portion in said hydraulic cylinder, there being port means constituting a part of said by-pass passage, and adapted to be closed by advance movement of said ram.

13. Apparatus as defined in claim 9 wherein an additional air cylinder is provided for effecting opening and closing swing of said lever, said additional air cylinder having a piston movable therein, and a piston rod having its end pivotally connected to said lever at a point intermediate the lever ends.

14. Apparatus as defined in-claim 5 wherein means is provided for restraining by-pass flow through said by-pass passage when said movable pressing member approaches fully opened position whereby to snub the final increment of opening movement of said movable member.

15. Apparatus as defined in claim 5 wherein the movable pressing member is provided with over-center linkage to actuate said movable member during opening and closing movement thereof, said toggle linkage being fully extended at an intermediate stage of relative movement, and being'jackknifed to collapsed position both at the fully open and fully closed position of the pressing members, and means for restraining by pass flow through said by-pass passage when said toggle linkage approaches collapsed position either near said fully open or fully closed position.

-16. Apparatus as defined in claim 2 wherein said bydraulic cylinder is completely filled with hydraulic liquid, and said by-pass passage is provided with a yieldable wall portion to compensate only for volumetric changes in the liquid-containing capacity of said hydraulic cylinder and said .by-pass passage by ram displacement upon movement of said ram portion within said hydraulic cylinder, there being port means constituting a part of said by-pass passage, and adapted to be closed by advance movement of said ram.

17. Apparatus as defined in claim 4 wherein a plurality of by-pass passages have their ends in communication respectively with said hydraulic cylinder ends to permit displacement of hydraulic fluid from one end of said cylinder to the other upon movement of said first piston, and wherein check valve means is disposed in one of said by-pass passages to permit liquid displacement in one direction only past said check valve.

18. Apparatus as defined in claim 17 wherein adjustable flow control means is provided in another said by-pass passage to control liquid flow through the last said passage upon movement of said first piston.

19. A laundry press of the character described having a frame, a movable pressing member and a fixed pressing member supported on said frame, means for bringing said movable pressing member into operative relationship with said fixed pressing member including a lever having said movable pressing member attached to one end thereof, said lever being pivotally supported on said frame at a first pivot point intermediate the ends of the lever, a fluid power cylinder unit pivotally connected to the frame and a second pivot point, said unit having a piston, a connecting rod extendable outwardly therefrom, the outer end of said rod being pivotally connected to said lever at a third pivot point on the lever end remote from said pressing member, said third pivot point being disposed to swing over-center across the line between said first and second pivot points upon movement of said lever to fully closed and to fully open position, a second fluid power cylinder unit for initiating approach movement of said lever to pressing position, said second fluid power References Cited in the file of this patent UNITED STATES PATENTS Raynolds Feb. 24, 1942 Powell Nov. 3, 1925 8 Davis N0v. 1, 1932 Daly Apr. 16, 1935 Kingsbury Apr. 23, 1935 'Rodal Aug. 110, 1943 Lornitzo Oct. 25, 1955 FOREIGN PATENTS Great Britain Nov. 30, 1948 Great Britain Nov. 30, 1955.

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