US1288472A - Form of press. - Google Patents

Description

H. E. BARR.

FORM OF PRESS.

APPLICATION FILED MAY 25. 1918.

Patented Dec. 24, 1916.

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HARRY EDSIL BARR. 0E ERIE, PENNSYLVANIA.

FORM OF PRESS.

Application filed May 25, 1918.

To all whom it may concern:

Be it known that I, HARRY EDsIL BARR, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented a new and useful Form of Press. of which the. following is a specification.

My invention has for its purpose the production of a machine for doing such work as forcing in or out of mandrels, arbors, shafts, bushing, pins, etc.,f0r pressing sheet metal into forming dies-for bending or straightening metal and all such work common to the usual lrvdraulic press. power press or hand press, etc.

The accompanying drawingl*igures 1 and 2shows the general construction and principles of operation.

In Fig. 1 a base 1 having its upper face in the form of a substantially ribbed platen for supporting the work, supports by means of posts 5- a cylinder 3. A piston 4: operates in the cylinder, its lower portion reduced in diameter to form a heavy piston rod which extends through a suitable packing box and guide as shown. The piston rod portion is attached at its lower end to a crosshead 6 which is guided against posts 5. A removable hardened steel nose 7 is provided as an abutment against arbors, pins, etc, of small size which thus impose a heavy concentrated pressure on a small area. The removal of nose 7 permits substitution of any desired piece such as a holder for a broach or punch. In case of work of considerable area, the nose is left out.

In Fig. 2 a reservoir 11 is provided, containing a liquid, preferably oil, the reservoir having. a capacity equal to or in excess of the volume of lower portion of cylinder at 8Fig. 1.

The press is intended to be operated by fluid pressure, preferably compressed air at common shop pressures of 80# to 100#.

Referring to Fig. 2 a four way cock at 12, admits the air at E and in position shown. passes it first through check valve 15 to top of cylinder where it exerts its pressure on top piston 1Fig. 1. and tends to move same downward. The downward movement of piston is prevented by liquid, preferably oil, in lower portion of cylinder at 8, and can occur only upon opening of regulating valve 17, by the operator, thus Specification of Letters Patent.

Patented Dec. 24. 1918.

Serial No. 236,653.

permitting the oil to be forced down into reservoir 11 per arrow G. The oil enters reservoir at bottom or substantially so. The downward motion of piston having been completed at any speed desired by the operator, and under his immediate control by means of valve 17, it is prevented striking the lower head of cylinder by reason of the connection at 10 being at a suitable height above bottom of cylinder. The piston closes opening 10 by passing over it and no further oil can escape-check valve 16 opening only in the reverse direction as per arrow B. It will be apparent that during the downward stroke of piston, with cock 12 in position shown, the reservoir is vented as per arrow I to exhaust at F, thus allowing oil to enter reservoir freely. I

In making the reverse or upward piston stroke, the operator reverses cock 12, connecting air supply at E with reservoir 11 as per arrow J, and connecting top of cylinder at 9 with exhaust F per arrow 1)- check valve 15 opening only in the reverse direction as shown. The air pressure on reservoir at or near its top, forces oil per arrow II and arrow B into bottom portion of cylinder under piston,regulating valve 17 being closed. The piston is thus forced upward until it passes over opening 9, when it cushions and prevents striking upper head.

It will be understood that the piping shown is diagrammatic for the purpose of illustration only and that the location of valves 12 and 17 would in practice be placed for the greatest convenience of the operator.

It will be understood also that in pressing sheet metal in dies, or other continuous production workparticularly requiring the hands of operator to be free, valves 12 and 17 may be operated by foot by a simple foot lever and connecting rods.

The advantages of this press are as follows Compared with such a machine using fluid pressure. as air or steam to force the piston, etc., against the work-but not using a liquid under control in the opposite end of cylinderthis press is positive in that it, will stop on the working stroke as soon as regulating valve 17 is closed, due to the incompressible liquid thus prevented from further exit from cylinder,-whereas the first mentioned type of press, with control only possible by shutting ofi the air pressure, would continue to move by expansion of the full pressure air then in cylinder. This prevents working to a given point unless a mechanical stop is provided-and is dangerous in pushing out work, when the resistance ceases suddenly, thus permitting piston to slam to bottom of stroke.

Compared with a hydraulic press as commonly understood, this press is practically unlimited in speed of working stroke-a feature of great value in continuous production Work, yet it is also controllable to any minimum of speed desired. It involves no excessive pressures with consequent packing difficulties and is independent of all power sources except the common shop air supply,-

being thus, in the smallersizes entirely portable and extremely simple,the portable hydraulic press requiring a pump therewith, operated by hand or frequently by electric power.

Compared with power driven forcing presses, this press is'free from the mechanical complications of gears, screws, etc., necessary in thus producing a heavy pressure from rotative power applicationit is independent. of all immediate power sources and is thus portable in the broadest sensea feature of great value in' many plantsit is installed without accessory expense of counter-shafts, belts, etc.,it cannot be overloaded by any act or negligence of the operator, so long as the shop air pressure does not'exceed the maximum for which press is designed, and this is fully guarded against by a simple safety valve on the air line to press. i

As compared with the common handwheel-and-screw press or the ratchet leverscrew-and-gear press, commonly used, this press eliminates manual labor in creating the tonnage, is vastly. more productive because faster and is not reduced in efficiency on continuous production, by the tiring of operator as when creating the pressure manually.

As compared generally with the types mentioned as' most commonly used today, this press is a substantial improvement in being most broadly and easily adapted to any class of forcing or pressing work required of such a machine in the average asagna shop whether slow or fast, continuous or intermittent, portable or stationary, etc.

What I claim and desire to protect by Let- Y adapted to support work being pressed; a

piston in said cylinder, having an extension adapted to come agalnst said work; a reservoir containing liquid, as oil, in connection With that end of cylinder nearest in efiect t said abutment; acontrolling valve in said connection; valve means of connecting end of cylinder farthest in effect from abutment,

and the reservoir, alternately, with either 'air. pressure or with atmosphere, to cause saidpiston to reciprocate; the admission of air pressure to said farthest cylinder end forcing piston toward abutment against resistance of said liquid passing to reservoir via said controlling valve; and admission of air pressure to reservoir forcing liquid from same to end of cylinder nearest abutment thus moving piston away from abutmentsubstantially as shown and described.

2. In a press, the combination of a cylinder; an abutment opposed thereto and adapted to support work being pressed; a piston in said cylinder, having an extension adapted to come against said work; a reservoir containing liquid, as oil, in connection with that. end of cylinder nearest in efiect to said abutment; a controlling valve in said connection; valve means of connecting end of cylinder farthest in effect from abutment, and the reservoir, alternately, with either air pressure or with atmosphere, to cause piston to reciprocate; the admission of air pressure to said farthest cylinder end forcing piston toward abutment against resistance of said liquid passing to reservoir Via said controlling valve; and admission of air pressure to reservoir forcing liquid from same to end of cylinder nearest said abut- HARRY EDSIL BARR.

Witnesses:

Jorm H. Nouns, DORMAN WEAVER,

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