US3604076A

US3604076A - Automatic screw-operated press

Info

Publication number: US3604076A
Application number: US882564A
Authority: US
Inventors: Leonard Brown; Foster B Cooley
Original assignee: CROSSLEY MACHINE CO Inc
Current assignee: CROSSLEY MACHINE CO Inc
Priority date: 1969-12-05
Filing date: 1969-12-05
Publication date: 1971-09-14
Anticipated expiration: 1988-09-14

Abstract

An automatic screw-operated press in which the ram is controlled in a ''''floating'''' condition independently of the screw by a pair of hydraulic cylinders, and in which the screw is operated by an air cylinder the piston of which is mounted on the shiftable disk shaft, the reciprocal ''''bumping'''' strokes of the screw being controlled by a pair of vertically spaced proximity switches actuated by a magnetic peripheral portion of the friction wheel.

Description

United States Patent .2.1 79,? 1 l 119295.Milli n w-i Inventors Leonard Brown;

Foster B. Cooley, both of Trenton, NJ. 882,564

Dec. 5, 1969 Sept. 14, 1971 Crossley Machine Company, Inc.

Appl. No. Filed Patented Assignee AUTOMATIC SCREW-OPERATED PRESS 7 Claims, 9 Drawing Figs.

u.s. c1 25/42, 18/16 c, 25/45, 25/84 1111.01 82% 3/02 Field ofSearch 25/42,43, 45,84; 18/166 References Cited UNITED STATES PATENTS 3,044,138 7/1962 Lesnett et al. 25/42 3,097,411 7/1963 Gerster et al. 25/45 3,179,998 4/1965 Lamb 25/84 3,359,608 12/ 1 967 Walchhutter 25/45 Primary Examiner-J. Spencer Overholser Assistant Examiner-Ben D. Tobor ABSTRACT: An automatic screw-operated press in which the ram is controlled in a floating" condition independently of the screw by a pair of hydraulic cylinders, and in which the screw is operated by an air cylinder the piston of which is mounted on the shiftable disk shaft, the reciprocal bumping" strokes of the screw being controlled by a pair of vertically spaced proximity switches actuated by a magnetic peripheral PATENTEDSEPMIQII 304l076 sum 1 OF 4 .Zeonard Brown. and 1 0518). 5 C k) /N l/EN TORS flrroe NE) PATENTEDSEPMBII 3.604.076

SHEETBUFA Leona/cl Bron/l2 and Taster ;B. Cooley //V VENTO/ZS By n Vh/CL/ 4 rro/aNEy AUTOMATIC SCREW-OPERATED PRESS This invention relates to automatic screw-operated presses for compressing pulverized clay or other powdered material into tile or other compact products adaptable to press and die production.

The press of the present invention is similar in general construction and operation to that disclosed in Miller US. Pat. No. 2,770,862, our invention residing primarily in two cooperative features of improvement in that press, namely, (I) control of the movements of the ram carrying the upper multiple die unit in a "floating condition by a pair of hydraulic cylinders, and (2) control of the multiple bumping" strokes of the screw by an air cylinder the piston of which is mounted on the shiftable friction disk shaft and actuated by a pair of proximity switches mounted in vertically spaced and aligned relation adjacent to the periphery of the horizontal friction wheel which is provided with a peripheral portion of magnetic metal or other magnetic material for actuating the switches alternately as the friction wheel is lowered or raised, for controlling the rotation of the screw in either direction.

It should be understood that in presses of the character mentioned the valves in the hydraulic and compressed air circuits may be of various electrical types, and that the electrical switches controlling such valves may act through any of numerous relays, timers, counters and other conventionalelectrical or electronic instrumentalities assembled in coordinated relation in a control cabinet or panel, instead of directly. Detail description of the construction and electrical circuits of such instrumentalities will be omitted in this specification, since they form no part of the present invention.

One of the principal objects of the present invention is to provide means in'combination with a pair of hydraulic cylinders and the press ram (1) for entirely releasing the ram from the screw into a floating condition, (2) thereby also enabling a sensitive initial impact of the upper multiple die unit upon the powdered material in the die cavities, and (3) enabling the ram to rise under the pressure of the air trapped in the material, as a result of the initial pressure impact of the end of the screw against the ram and upper die unit, immediately after the reversal and lifting of the screw, thereby permitting the escape of the trapped air through clearances allowed between the upper and lower die units.

Another object of the invention is to provide a control of the multiple impacts or bumps of the screw against the material in the die cavities in the final compacting operation on the tile or other product by means of proximity switches, thereby eliminating the wear and tear prevalent in the levers, mechanically operated switches and other mechanical elements previously employed in shifting the friction disks into and out of contact with the friction wheel, and also reducing the cost of maintenance and the delays in production caused by the resulting necessity of repairs and replacements.

Other objects and advantages of our improvements will be apparent or pointed out in the following specification in which reference is directed to the accompanying drawings forming a part thereof, and in which FIG. I is a front elevation of a screw-operated press for forming clay tile, with certain parts wholly or partly in section or removed for greater clarity of illustration, and showing the die cavities filled with clay dust or other powdered material;

FIG. 2 is a fragmentary view similar to FIG. 1 showing the initial light impact of the ram and upper die unit upon the powdered material;

FIG. 3 is a view similar to FIG. 2 showing the initial power or pressure impact of the end of the screw on the powdered material, through the "floating" ram and impact plate therein;

FIG. 4 is a side elevation of the press shown in FIG. I, after completion of a cycle of pressing operations, with the die case in its uppermost position and with a batch of tile or other products pressed in the previous cycle in position to be pushed onto a take-away conveyor by the dust box at the beginning of the next cycle of pressing operations;

FIG. 5 is an enlarged detail view showing one of the hydraulic cylinders as in FIG. 1;

FIG. 6 is a detail view similar to FIG. 5 but with the hydraulic cylinder and ram controlled thereby as shown in FIG. 2;

FIG. 7 is a detail view showing the neutral relation of the proximity switches and friction wheel as in FIG. 4;

FIG. 8 is a plan sectional view through one of the proximity switches; and

FIG. 9 is a detail section of the air cylinder, as shown in F IG. 1, for axially shifting the friction disk shaft.

Referring to the drawings in whichlike numerals designate like parts in the several views, it is to be understood that the various switches indicated are connected with proper electrical relays, timers and electrical counters of conventional design (not shown), assembled in coordinated relation in a control cabinet or panel 10 to effect the functions of the various valves as described hereinafter; also that the valves indicated may be of any solenoid or other conventional electri: cal types suitable for the operational steps referred to. Therefore, detailed description of such elements and the electric circuitry involved will be omitted as forming no part of the present invention. 7 v

The press illustrated includes a base 12 mounting a stationarylower multiple die unit 14. A multiple impact die unit 16 depends from the lower end of a ram 18 slidably mounted on stationary rods 20 supported on the base 12, said unit being opposed to the lower die unit 14. Laterally projecting from each side of the ram 18 is a horizontal flange 22 having therein a vertical bore 24 (FIGS. 5 and 6) through which loosely projects the piston rod 26 of a hydraulic cylinder 28. A pair of adjustable nuts 30 is mounted on the upper threaded portion of the piston rod in vertically spaced relation and with the lower nut below the flange 22, thereby leaving a substantial space between the upper nut and the top surface of the flange 22.

Hydraulic fluid pipes

32 and 34 are provided with

electrical valves

32a and 34a, which are connected with cooperative elements (not shown) in the control cabinet 10 for effecting reciprocal axial movements of piston rod 26 together with ram 18 in predetermined'sequence.

A large vertical screw 36 has an intermediate threaded por tion 36a extending through a stationary bearing member 38 and a reduced unthreaded lower end portion 36b projecting through an auxiliary bearing 38a into a recess 18a in theram l8 in the bottom of which is an impact plate 40. The upper end of the screw 36 is keyed or otherwise rigidly secured to a horizontal friction wheel 42.

Friction disks

44 and 46 are mounted on an axially shiftable shaft 48 which is journaled in

bearings

50 and 52 carried by hearing member 38. This shaft is alternately shifted in either axial direction by means of the piston P of an air cylinder 54 supported on the bearing member 38, said piston being mounted directly on the friction disk shaft 48. The piston is shifted through electrical valves 54a and 54b, as will hereinafter be described. Outwardly of disk 46 on shaft 48 is a pulley 56 carrying a belt 58 which extends to a drive pulley 60 on an electric motor 62, which motor is mounted on hearing member 38. When in operation the shaft 46 is driven continuously in one direction.

The friction wheel 42 is of special construction, as shown more clearly in FIGS. 4 and 7, in that it is'provided with an outer rim or annular peripheral portion 64 made of a magnetic metal or other suitable magnetic material, and with an ex treme outer band 66 of friction material for frictional contact with the

friction disks

44 and 46.

A- pair of

proximity switches

68 and 70 are mounted, through a support 72, on the bearing member 38 in vertically spaced and aligned relation adjacent to the vertical peripheral plane of the friction wheel 42, so that the proximity switches will be respectively actuated when opposite the periphery of the friction wheel. The switch element 74 of each of the

proximity switches

68 and 70 is enclosed in a rectangular casing 69 and is connected through other cooperative elements (not shown) with air cylinder valves 54a and 54b, to effect the final multiple or bumping impacts of the screw 36, against the impact plate 40, as will hereinafter be further described.

The Construction and operation of the die case 76 is substantially the same as that shown and described in the Miller patent referred to, that is, it is raised to form the die cavities C, and lowered to allow pushing of a batch of tile T or other pressed products from the dies, by means of an air cylinder 78 through

valves

80 and 82 actuated in cooperative sequence with the dust box 84 and other associated instrumentalities through elements (not shown) in the control cabinet 10.

As shown in FIG. 4, the dust box 84, which has a sievelike bottom, is reciprocally operated in a horizontal plane on a support 86 by means of the piston rod 88 of a hydraulic cylinder 90, the interconnected lever 92 with pairs of transversely spaced levers 94 and connecting rods 96 attached to the dust box 84, the latter having on its forward end a bumper 84a for pushing completed tile T from the die as will hereinafter be described. The hydraulic cylinder 90 operated through electrical valves 90a and 90b controlled by limit switches 98, 98a, 98b, 98c and 98d mounted on a support 100 and actuated in proper sequence by a cam 94a on lever 94 and cooperative with associated elements (not shown) in control cabinet 10.

Limit switches 102, 102b and 102d mounted on a support 104 and actuated by contact elements 102s and 102]" carried by ram 18, and connected with valves 54a, 54b of air cylinder 54 and also cooperative elements (not shown) in control cabinet control an initial pressure stroke of the large screw 36 independently of the bumping strokes controlled by the

proximity switches

68 and 70, as will hereinafter be described.

With respect to the operation of the press described it should be understood that after being started into operation by the closing of a starting switch S on the control cabinet 10, which switch is connected through cabinet 10 with a main electrical circuit (not shown), it will continue automatic operation in repeated cycles until stopped by the opening of the starting switch, in the same general manner as described in the Miller patent referred to.

As shown in FIG. 4, the dust box 84 has been returned to its back or starting position after the completion of a cycle of pressing operations, this being effected by the tripping of electrical limit switch 98d by cam 94a on lever 94 at the extreme end of its last forward stroke,which actuated electrical valve 90b on hydraulic cylinder 90, thereby leaving a batch of tile T on top of bottom die unit 14 in coplanar relation with the top surface of die case 76, which will have been lowered by air cylinder 78 through electrical valve 80 actuated by limit switch 90c tripped by cam 940 during the back stroke of dust box 84, which stroke also opens a hinged gate 106 on hopper 108 (by mechanical means not shown) to fill the dust box with a charge of powdered clay I 10 or the like for the next cycle of operations.

At the extreme end of the back stroke of the dust box 84 limit switch 98 will have been tripped by cam 94a, thereby automatically starting a new cycle of pressing operations by forcing the dust box forwardly to a position over the lower multiple die unit 14 with the bumper 84a on its front end pushing the batch of tile T, or other products, pressed in the previous cycle onto a take away conveyor 112. As dust box 84 reaches its maximum forward movement limit switch 98d is actuated by cam 94a which energizes electrical air valve 82 thereby causing air cylinder 78 to raise die case 76 to form multiple die cavities C (FIG. 1) above the lower die unit 14 for receiving a new charge of clay dust or other powdered material from the dust box 84. At the extreme end of the forward stroke of the dust box limit switch 98d is actuated thereby again energizing valve 90b on hydraulic cylinder 90 thus reversing the movement of piston rod 88 and returning dust box 84 to its back or starting position, as shown in FIG. 4. However, before completion of its reversed movement the dust box, through cooperative actuation of limit switches 98b and 980, alternately energizing valves 90a and 90b on hydraulic cylinder 90, will have been subjected to a series of short and rapid reciprocative or vibratory strokes thereby shaking the charge of dust therein into the die cavities C, as shown in FIG. I, the extent of the vibratory action being controlled by a timing element (not shown) in the control cabinet.

As the dust box 84 completes its back stroke to starting position, as shown in FIG. 4, limit switch 98, connected through control cabinet 10 with

electrical valves

32a and 34a on hydraulic cylinders 28 is tripped by cam 940, which applies hydraulic pressure to the upper ends of the cylinders, thereby disengaging the lower nuts 30 from the bottoms of flanges 22, thus leaving ram 18 in a floating" condition and permitting the multiple upper die unit to be lowered at controlled speed into a light impact on the powdered material 110 in the die cavities C. This forces part of the air from the material in what may be called the initial dc-airing" step, as shown in FIG. 2. As ram 18 begins its downward movement limit switch 102 is actuated by contact element l02f this switch being connected through control cabinet 10 with valve 54a on air cylinder 54, the energizing of which shifts disk 44 against friction wheel 42 causing screw 36 to follow the ram downwardly until the lower end of the screw comes into abutment with the impact plate 40 in the ram 18, thereby applying the initial power bump or pressure stroke to the clay dust or other powdered material 110 in the die cavities C, as shown in FIG. 3. This further compresses and dc-airs" the material in the cavities. Due to the floating condition of the ram 18 it will rise by reason of the force exerted by compressed air within the partially compressed material when released from the pressure of the end of the screw 36, thereby permitting the escape of this air through clearances allowed between the punchlike formations of the

dies

14 and 16, thus ensuring ultimate greater hardness and solidity of the tile T or other pressed products.

Final hardness of the tile T or other pressed products is obtained by reversing screw 36 immediately after its initial impact on impact plate 40 and then subjecting it to a preset plurality of pressure strokes by means of proximity switches 68 and 70 connected with valves 54a and 541; as previously explained. These switches are controlled by automatic electric counters or other suitable relay and switching elements (not shown) so that as the friction wheel 42 comes into the horizontal plane of one of said switches it will cause reversal of rotation of the wheel and send it into the plane of theother switch. When the preset number of bumping strokes has been reached the automatic counter will act through valves 114 on air brake cylinders 116 to stop friction wheel 42 in its uppermost position, as shown in FIG. 1.

After the last bump" of screw 36 against ram 18 the latter is returned to its uppermost position, as shown in FIG. I, by said counter and switch means (not shown) acting through valves 34a on hydraulic cylinders 28 to force the lower nuts 30 on piston rods 26 into lifting engagement with the bottom surfaces of the flanges 22 on the ram. In this position the upper nuts 30 are spaced above the top surfaces of the flanges 22 to permit a floating" condition of the ram, as shown in FIGS. 2 and 3. However, if the ram becomes stuck during its downward movement it will be freed by engagement of the upper nuts 30 with the top surfaces of the flanges 22.

During the return of the ram 18 to its uppermost or starting position limit switch 102 connected with valve on air cylinder 78 is tripped, which applies air pressure to the top of the cylinder thereby lowering die case 76 to its lowermost position, as shown in FIG. 4, and leaving the batch of tile T or other pressed products flush with the top surface of the die case 76 to be pushed by dust box 84 onto takeaway conveyor 112.

The automatic operation of the press will continue in repeated cycles until stopped by opening of starting switch 5, as previously mentioned.

Various changes or modifications may be made in our improved features of press construction and operation without departing from the spirit or scope of our invention, as defined in the appended claims. Therefore, it should be understood that the specific constructions shown and described are intended to be illustrative only and not restrictive thereto.

We claim:

1. In an automatic screw-operated press of the type including a base, an axially shiftable shaft journaled on said base and having a pair of disks fixedly mounted thereon, a friction wheel mounted horizontally between the opposed faces of said disks on the upper end of a vertical screw threadedly mounted in said base for rotary and reciprocal axial movement therein, a ram mounted for vertical movement on said base in opposed relation to the lower end of said screw for selective abutting impacts thereon, an upper die unit depending from said ram, a lower die unit on said base opposed to and cooperative with said upper die unit, and means for supplying powdered material to said lower die unit; said ram having on each side thereof a laterally projecting flange provided with a vertical bore through which projects a threaded piston rod of a hydraulic cylinder supported on said base and an adjustable nut on said piston rod for engagement with the bottom surface of said flange to permit lowering of the ram and upper die unit at a speed controlled by a pair of electrical valves connected with said hydraulic cylinder into an initial light impact on the powdered material in the lower die unit.

2. An automatic screw-operated press as in claim 1 and including an air cylinder having its piston mounted on said shiftable shaft for shifting either of the friction disks thereon against said friction wheel in efiecting axial movement of the screw in either direction; electrical switch means actuated by the downward movement of said ram and cooperative with electrical air valves connected with said air cylinder for effecting the downward movement of said screw into an initial pressure impact against said ram and returning it to its uppermost position; and also including a pair of vertically spaced proximity switches supported on said base, said switches being independently actuated by magnetic material in the peripheral portion of the friction wheel as it alternately moves into coincident relation with either of said switches, which are cooperative with said electrical air cylinder valves for effecting a preset plurality of pressure impact strokes of the end of the screw against said ram to impart final hardness to the products into which the powdered material in the lower die unit is being pressed.

3. An automatic screw-operated press as in claim I and including an additional nut on each of the threaded piston rods controlling the vertical movement of the ram, these nuts being on the outer ends of the piston rods at a spaced distance above said lateral flanges projecting from said ram.

4. An automatic screw-operated press as in claim 1 in which the magnetic material in the peripheral portion of the friction wheel comprises an annular rim made of magnetic material, and in which said rim is encircled by a band of friction material for contact with the respective friction disks.

5. An automatic screw-operated press as in claim 1 and including a contact plate on said ram opposed to the lower end of the screw.

6. An automatic screw-operated press as in claim 2 in which each of said proximity switches includes a rectangular casing enclosing the switch element, each of said casings being mounted in vertically spaced and aligned relation in close proximity to the plane of vertical travel of the periphery of the friction wheel on a stationary support attached to the press base.

7. An automatic screw-operated press as in claim 2 in which said proximity switches are cooperative with valves connected with air cylinders operating brakes above the friction wheel for applying said brakes against and stopping rotation of said friction wheel upon completion of said preset plurality of impact strokes of the end of the screw against the ram.

Claims

2. An automatic screw-operated press as in claim 1 and including an air cylinder having its piston mounted on said shiftable shaft for shifting either of the friction disks thereon against said friction wheel in effecting axial movement of the screw in either direction; electrical switch means actuated by the downward movement of said ram and cooperative with electrical air valves connected with said air cylinder for effecting the downward movement of said screw into an initial pressure impact against said ram and returning it to its uppermost position; and also including a pair of vertically spaced proximity switches supported on said base, said switches being independently actuated by magnetic material in the peripheral portion of the friction wheel as it alternately moves into coincident relation with either of said switches, which are cooperative with said electrical air cylinder valves for effecting a preset plurality of pressure impact strokes of the end of the screw against said ram to impart final hardness to the products into which the powdered material in the lower die unit is being pressed.

3. An automatic screw-operated press as in claim 1 and including an additional nut on each of the threaded piston rods controlling the vertical movement of the ram, these nuts being on the outer ends of the piston rods at a spaced distance above said lateral flanges projecting from said ram.