US2400996A

US2400996A - Metal shear

Info

Publication number: US2400996A
Application number: US569358A
Authority: US
Inventors: Iversen Lorenz
Original assignee: Mesta Machine Co
Current assignee: Mesta Machine Co
Priority date: 1944-12-22
Filing date: 1944-12-22
Publication date: 1946-05-28
Anticipated expiration: 1963-05-28

Description

y 1946- LJVERSEN 2,400,996

METAL SHEAR Filed Dec. 22, 1944 6' she ts-sheet 1 May 28, 1946.

L. |VERSEN METAL SHEAR Filed Dec 22, 1944 6 Sheets-Sheet 3 Zone 2 Wersn May 28,1946. LQIVERS EN META L SHEAR File d Dec. 22. '1944 j; 6 sh ets-Sheet '4 INVENTOR L. IVERSEN METAL SHEAR May 28, 1946.

Filed Dec. 22, 1944 e Sheets-sheaf 5 %W kw QM 2 3 J J 3 l 1.

WINVENTOR 029/72 Wersen ,m #WIJA L. IVERSEN METAL SHEAR I May 28,1946.

e Sheets-Shet 6 Filed Dec; 22, 1944 MN MS mu MN Patented May 28, 1946 METAL SHEAR Lorenz Iversen, Fittsburgh, Pa., assignor to Mesta Machine Company, Pittsburgh, Pa., a corporation of Pennsylvania Application December 22, 1944, Serial No. 569,358

oFFflc 6 Claims.

This invention relates to metal shears and, in particular, to a plate shear adapted for cutting large and heavy metal plates.

Plate shear heretofore in use have been subject to many disadvantages, particularly when they are of such size as'tocut very large, thick there is a fluid-pressure cylinder 24 connected we link 25 to a crank 26 on a rock shaft 21. The rock shaft is mounted in bearings 28 secured to the casting l3a by bolts 29. Lifting fingers 30 on the shaftfl engage the lower ends of the posts: 16 to raise them when fluid under pres plates. My improved shear is a self-contained hydraulically operated shear, which constitutes a compact unit of superior design and construction, and having great flexibility of operation.

In the accompanying drawings illustrating a present preferred embodiment of the invention,

Figure 1 is a front elevation of-the shear of my invention;

FigureZisaplanview; Figure 3 is a partial vertical section taken along the plane of line lII-III of Figure 2;

Figure 4 is an end elevation such as would be seen by looking from the right in Figure 1;

Figure 5 is a transverse section taken along the plane of line V-V of Figures 1 and 2;

Figure 6 is a view partly in front elevation, with certain parts removed, and partly in section along the plane of line VI-VI of Figure 2;

Figure 7 is a partial vertical section taken along the plane of line VIL-VII of Figure 2;

Figure 8 is a plan view with parts omitted and l a part broken away showing thepump cylinders and the ram cooperating'therewith insectionf on i a horizontal plane through their axes;

Figure 9 is a partial, elevation of the control valves such as would be seen by looking from the left in Figures 1 and 8; and

Figure 10 is a partial section plane of line X- -X of Figure 9.

General arrangement Referring in detail to the drawings, andfor taken along the the present to Figures 1 through 7, there is shown a base l0 carrying uprights II and I2. "Atable sureis admitted to the cylinder 24. The roller l5 may be lowered by releasing 'the fluid pressure from the cylinder 24.

Just behind the Shea!" blade ll there is veyor for carrying away the sheared scrap. It consists of a conveyor chain 3| moving on a track 32 secured to the back of the casting i3: and around driving and idlersprockets 33 and 34; The sprocket 33 is driven byany convenient means through ashaft 35. i

A Upper shear knife mounting As best shown in Figures 4 and 5, the uprights H and I2 are massive ribbed castings having portions 36, overhanging the table I3and conveyor 3l,-and providing recesses 31 togive ample room for manipulation, as well as to accommmdate the portionof the plate'which is to be sheared oil. Pockets 38 are formed in the upper part of thejoverhanging portions 36. Guides 39 below the pockets accommodate the ends of a vertically slidable crosshead 40 which carries the movable shear blade.- The ends of the crosshead are confined in the guides by keeper plates 4| secured to the uprights by T-head bolts 42. A

movable shear blade 43 is mounted on the'crossheadat an angle to the fixed blade It so that of which is operatively connected to the correspending end of the crosshead 40. The fixed elements "of the dam-and-cylinder combinations portions 36 of the uprights by eye bolts 45.

agear-motor I! through shafts l8, l9 and 20,

the latter including universal Joints 2|. The shafts are connected by

bevel gears

22 and 23.

For the purpose of raising the roller I! to operative position for manipulating a plate,

Anchor pins 46 extend through holes in the uprights and through, the eyes of the-bolts 5. The blocks ll have rams 41 formed integral there,- with which fit into cylinders 48 lying within the pockets 38. The loweryends of the cylinders engage pivotal bearing blocks 49 carried on the ends of" the crosshead 40. Fluid-supply passages 50 andll drilled in the blocks and rams l1 permit fluid under pressure to be supplied to the a COD- Figure 3. Two of these suspensions are secured to each end of the crosshead as indicated in Fi ures 2 and 8. Each suspension comprises nested compression springs 51 supporting a hanger rod 58 secured to a lifting lug 59 formed on the crosshead. The springs 51 are compressed as the crosshead is lowered by the supply of fluid under pressure to the interior of thecylinders 48. As soon as the pressure on the fluid is relieved, the springs raise the crosshead to its uppermost position, thereby expelling fluid fromthe cylinders.

Plate clamping mechanism A beam 88 extends between the uprights and is secured to the keeper plates 4| by screws 6|.

(Pockets 82 are formed in the beam to accommodate the lugs 59 when the crosshead descends.) A set of fluid-pressure cylinders 83 is spaced along the beam 88. The cylinders have pistons therein provided with plungers 84 adapted, when extended, to engage a plate on the table and clamp it firmly in position for shearing. Oil under pressure is delivered to the cylinders 83 by a pump 65 driven by a motor 68, both of which are mounted on the girder 53.- A valve 61, also mounted on" the girder, controls the flow of oil through suitable pipe connections, as shown in Figures 1 and 2, to a manifold passage 68 inthe beam 88. Connecting passages through the beam (not shown) extend from the passage 88 to the cylinders 83 through individual valves 69.. The valves 89 are provided so that the rate of movement of the several plungers may be equalized or otherwise regulated. The cylinders 83 have compression springs therein (not shown) below theplungers for returning the latter to raised position when the pressure on the fluid in the cylinders is relieved. L

Pum p mechanism for actuating shear b la'de The cylinders 48 are supplied with oil under pressure from a pump 18 through control valves formed in a valve block 1 I. a cylinder 12 slidable on horizontal guides in one end Of a gear case 13 which extends between the uprights II and I2. A fixed ram 14, integral The p mp comprises with the block 1|, extends into-thev cylinder 12.

The block and the ram are secured to the case by bolts 15.

The cylinder 12 has two coaxial. chambers in tandem, the relative diameters of which are'such that the same amount of oil is displaced from each chamber by a given movement of the cylinder. The ram 14, as shown, has portions corresponding in'size to the diameters of the two chambers in the cylinder. Passages 18 and 11 extending through the ram communicate with the chambers, respectively.

'The' pump cylinder has trunnions 13 for connecting rods 19. The other ends of the'rods engage eccentrics 88 secured to a shaft 8| journaled in the case 13. The shaft 8| is driven by a motor 82 mounted on the girder 53. The motor is couoperated.

Poppet valves

81 and 88 are provided for controlling the passage of oil to the rams 41 (see Figures 9 and 10). These valves are normally urged against's'eats formed in chambers 89 and 98' by compression springs 9|, the valves being slidable in sleeves 92. The springs and sleeves are held in position by plugs 93 bolted to the block". The passages 16 and 11 in the ram 14 intersect the

chambers

89 and 98, as best shown in Figure 9.

Connecting passages and 95 extend downwardly from the

chambers

89 and 98 to a horizontal channel 98. A pipe connection 91 extends from one end of this channel to an oil reservoir 98formed in the upper removable portion or cover of the'gear case 13. A rock shaft 99 is journaled in bearings in the channel 96 and has lifting fingers I88 thereon for engaging the lower ends of the stems of

the'valves

81 and 88. By this construction,

thefvalves

81 and 88 may be raised from their seats by counter-clockwise rotation of the shaft 99 as viewed in Figure 10.

So long as the

valves

81 and 88 arejlifted from their seats, oilis free to flow from the cylinder 12, as it moves leftward, to the reservoir 98 through the passages 18 and 11, the

valve chambers

89 and 98,

passages

94 and 95, channel 98 and pipe 91. When the cylinder is retracted, the oil flows back into the chambers thereof from the reservoir by the same paths. This cycle is repeated during continuous operation of the motor 82 until the

valves

81 and 88 are closed.

If the

valve

81 and 88 are closed, oil supplied from the chambers in the pump cylinder through passages 16and 11 to the valve chambers 89 and '98 can pass only through passages l8! and I82 in the block 1|, from which pipe connections I83 and I84 extend to the piston blocks 44 on the uprights II and 12, respectively. The crosshead 48,.is thus forced downwardly compressing the springs of suspensions .52, when the pump is operated with the

valves

81 and 88 closed. Since equal amounts of oil are displaced from the two chambers of the cylinder 12, both'ends of the crosshead are forced downwardly at the same rate under, equal pressures. When the downward stroke of the crosshead has been completed, continued operation of the motor 82 will retract the cylinder 12. The pressure in the cylinders 48 being thus relieved, the spring suspensions 52 raise the crosshead and force the oil from the cylinders 48 back into the pump chambers.

g I Shear control The starting point of a shearing cycle is that at which the various parts of the shear are in the positions shown in Figures 6 and 8. After a plate has been positioned for shearing, the operator will close a push-button switch, not shown, for effecting a shearing stroke. It is important, however, that the closing of the

valves

81 and 88 be properly timed with the reciprocation of the cylinder 12, regardless of the instant when the push-button is pressed. The mechanism shown block'll.

mounted on a bracket; secured to the gear case, is driven from the shaft-8| by a chain-andsprocket drive I08 and bevelgearinl I81. The limit switch functions in a known manner to complete an energizing circuit fora adenoid-operated mechanism adapted to close valves 81. and 88,

only when the cylinder 12 is fully retracted. This mechanism operates the rock shaft 89 in. the

valve block 1| to shift the control valves. It includes a solenoid I 08 adapted to be energized on the closing of its circuit by the limit switch. Tl ls circuit, is set up in advance by manual operation of the push-button which must be continuously held down to start and carry through a shearing cycle. The solenoid actuates a bell crank I89 pivoted on the gear case at IIO, acting through a collapsible spring linkage I Illa. The bellcrank I88 has one arm which is generally horizontal and another arm "19b which is substantially vertical. Alink III is pivoted to the arm I09!) and to a crank arm I I2 secured to an end of the shaft 89 which As stated, the starting point of a shearing cycle is that at which the various parts of the shear have the positions in which they are illustrated in Figures 6 and 8. When the parts reach such positions, in the continuous rotation of shaft 8|, energization of the solenoid I88 is effected by the limit switch, which completes a circuit previously prepared by operation of the push button. The

valves

81 and 88 are thus permitted to descend onto their seats. This results from counterclockwise rotation of the bell crank I09 and the corresponding clockwise rotation of the shaft 89 effected by the link III. The pump 18 then delivers oil under pressure to the cylinders 48 as already described and the crosshead moves downwardly.

The

valves

81 and 88 are opened when the crosshead reaches the bottom of its stroke, i. e., when the pump cylinder 12 reaches the extremity of its leftward movement caused by clockwise rotation of the gear 85, even though the operator continues to hold the push button down, maintaining con-' tinued energlzation of solenoid I08. For this purpose, a cam III on the shaft 8| has a high portion which engages a roller IIS on the arm I081:

, of the bell crank I09, when the shaft 8| has turned through about 180 degrees. The cam thus returns the bell crank to the illustrated position,

projects outwardly of the f My shear has numerous advantages over those heretofore employed. It is extremely rugged in construction and suitable for heavy duty. The mechanism is compact, simple and easilycon trolled. The hydraulic pump and motors are not subject to material wear orlikely to get out of order. The driving motor employed need not be unduly large because substantial energy may be stored .in' the drive mechanism for a cutting stroke, and this energy is translated into shearing pressure witha minimum of shock.

I haveillustrated and described a present preferred embodiment of the invention. It. will be I understood that this is by way of illustration only by compressing the spring linkage IIIla if the solenoid continues to be energized, and raises the

valves

81 and 88 from their seats. As illustrated, the cam is arranged for clockwise rotation of the shaft 8I. The opening of the valves connects the reservoir 98 to the pump chambers, relieves the pressure in the cylinders 48, permitting the suspensions 52 to raise the crosshead, and insures that the pump chambers will be completely filled as the cylinder is retracted. Normally the fluid from the cylinders 48 will fill the pump chambers but any slight leakage which may occur is made up by additional fluid supplied from the reservoir. The same result follows if the operator releases the push button at any time durand that the invention may be otherwise embodied or practiced within'the scope of the following claims. I claim: 1. A plate shear comprising a pair of elongated cooperating shear blades, afirst hydraulic press unit operatively connected to one of said blades,

a second hydraulic press unit ope'ratively connected to said one of said blades but at; a point spaced from the first press unit, a pump for each of the units adapted to supplyit with fluid under pressure, fluid connections between'the pumps and the respective pressunits, means for sub-' stantially continuously actuating thepumps, a

fluid receiver, and valve means for directing the output of the pumps to the receiver or to the re spective press units.

2. A plate shear comprising a pair of elongated cooperating shear blades, a first positive-displacement hydraulic press unit operatively connected to one of said blades, a second positive-displacement hydraulic press unit operatively connected to said one or said blades but at a point spaced from the first press unit, a positive-displacement pump for each or the units adapted to su ply it with fluid under pressure, fluid connections between the pumps and the respective press units, means for substantially continuously actuating the pumps, a fluid receiver, and a valve means for directing the output of the pumps to the receiver or to the respective press units.

3. A plate shear comprising a pair of elongated v cooperating shear blades, a first hydraulic press unit operatively connected to one of said blades; a second hydraulic press unit operatively connected to said one of said blades but at a point spaced from theflrst press unit, a positive-displacement pump for each of the units adapted to supply it with fluid under pressure, fluid connections between the pumps and the respective press units, means for substantially continuously actuating the pumps, 9. fluid receiver, valve means for directing the output or the pumps to the receiver or to the respective press units, and means operating in timed relation with said pump for tripping said valve means. .1

4. A plate shear comprising a pair of elongated cooperating shear blades. a first positive displacement hydraulic-press unit operatively connected to one of'the blades, a second positive-displacement hydraulic-press u t opratively connected to one of the blades bu at a point longitudinally spaced from the pointoi' connection of the first press, unit, a positive-displacement pump for each of the units, means'for substantially continuously actuating the pumps,,a fluid receiver, a fluid conduit connecting each pump with the receiver, a valve in each, conduit whereby the pump may pump fluid to and from the receiver when the valves are open, the valves being arranged to Drevent fluid flow from the pump to the receiver when closed, a constantly open fluid conduit connecting each pump and its corresponding press unit, each conduit bypassing the valve tor its pump, means constantly biasing the shear blades against shearing movement whereby the press units, although: in constant fluid commumcation with their respective pumps, do not efiect shear movement except upon closing of the valves, and means for opening and closing thevalves.

5. A plate shear comprising a pair of elongated cooperating shear blades, a first positive-displacement hydraulic-press unitoperatively connected to one of the blades, a second positive-displacement hydraulic=press unit operatively connected to one of the blades but at a point longitudinally spaced from the point of connection of the first press unit, a, positive-displacement pumpfor each of the units, means for substantially continuously actuating the pumps, a fluid receiver, a fluid conduit connecting each pump with the receiver, a valve in each conduit whereby the pump may pump fluid to and from the receiver when the valves are open, the valves being arranged to prevent fluidflow from the pump to the receiver when closed, a constantly open fluid conduit connecting each pump and its corresponding press unit, each conduit bypassing the valve for its pump, means constantly biasing the shear blades against shearing movement whereby the press units, although in constant fluid communication with their respective pumps, do not effect shear movement except upon closing of the valves,

means biasing the valves to closed position, and means for optionally holding them in open position.

3) pump stroke for releasin 6. A plate shear comprising a pair or elon ated cooperating shear blades, a first positive-displacement hydraulic-press unit operatively connected to one of the blades, a second positive-displacement hydraulic-press unit operatively connected to one of the blades but at a point longitudinally spaced from the point of connection of the first press unit, a positive-displacement pump for each of the units, means for substantially continuously actuating the pumps, a fluid receiver, a fluid conduit connecting each pump with the receiver, a valve in each conduit whereby the pump may pump fluid to and from the receiver when the valves are open, the valves being arranged to prevent fluid flow from the pump to the receiver when closed, a constantly open fluid conduit connecting each pump and its corresponding press unit, each conduit bypassing the valve for its pump, means constantly biasing the shear blades against shearing movement whereby the press units, although in constant fluid communication with their respective pumps, do not effect shear movement except upon closing of the valves, means biasing the valves to closed position, means for optionally holding them in open position, and trip means operating in timed relation to the the holding means. LORENZ IVERSEN.