US1529746A - Pneumatic device for automatic die presses - Google Patents

Description

March 17. 1925.

c. D. M DONALD PNEUMATIC DEVICE FOR AUTOMATIC DIE PRESSES Filed Dec. 1'7, 192$ a wm, 4g 79 Patented Mar. 17, 1925.

UNITED STATES PATENT OFFICE.

PNEUMATIC DEVICE FOR AUTOMATIC DIE PRESSES.

- Application filed December 17, 1923. Serial No. 681,101.

To all whom it may concern:

Be it known that I, CHARLES D. MCDON- ALD, a citizen of the United States, and a resident of Chicago, Cook County, and State of Illinois, have invented certain new and useful Improvements in Pneumatic Devices for Automatic Die Presses, of which the following is declared to be a full, clear, and exact description. 7

The invention relates to pneumatic devices for die presses and its principal object is to provide a pneumatic device operated by an element of the die press mechanism, capable of creating a partial vacuum for the strip lifters of the press and capable of supplying compressed air for use in blowing away the stampings. It is well understood, that with many automatic die presses, the work (which usually comprises thin strips of metal) is lifted, one strip at a time, and inserted into the feed way where it is fed to the dies to be stamped up into articles. Usually the strip lifters are 1n the form of vacuum devices and a vacuum-pump is employed for providing the partial vacuum for the strip lifters. The pump is usually operated by a driving member of the die press mechanism. In many cases when stamping metal articles with automatic die presses, especially when #the depth of the article is one half of an inch or more it is necessary to blow the stamped pieces away from the dies after being formed, to attain high speed and to avoid clipping such pieces on the next down stroke of the punches. With the present invention the necessary vacuum is maintained for lifting the metal strips, and air blasts are produced in timed relation to the strokes of the punches for blowing away the stamped pieces, thereby facilitating the work in high speed die presses.

The invention consists in the several novel features hereinafter set forth and claimed. The invention is clearly illustrated in the accompanying drawing, in which:

Fig. 1 is a side elevation of automatic die press mechanism, showing one embodiment of the invention applied thereto; Fig. 2 is a detail, central section through the pneumatic cylinder; Fig. 3 is a detail, longitudinal section through the vacuum chamber ofv the pneumatic cylinder, and'Fig. 4 is a detail, vertical, longitudinal section through a fragmentofthe air nozzle. Referring to said drawing, which illustrates a simple embodiment'of the invention press head 5, is a pneumatic cylinder 11,

closed by heads 12, 13 at its ends and con taining a piston 14. The piston is secured upon one end of a'piston rod 15 which is connected to an arm 16 bolted or otherwise secured to the pitman 7 The cylinder 11 is fulcrumed on its bracket, whereby it may oscillate thereon and the parts are so arranged that the rotary movement of the crank 8, is translated into reciprocatory movement of the piston rod and piston. The piston travels from end to end of the cylinder, and at one side of the piston causes a partial vacuum for the strip lifters, and at the other side compresses air for delivering blasts of air to the dies. The end 17, forms the vacuum side of the cylinder and the end 18 forms the compression side thereof. At the vacuum side 17 is a valve casing 19 in which is an air intake chamber 20 and an air discharge chamber 21 separated by a partition 19. In the partition between the two chambers is a port 22 which is closed by an inwardly opening check valve 23, and leading out from the discharge chamber 21 is a discharge port 24 closed by an outwardly opening check valve 25. Threaded in the valve casing 19 and opening to the intake chamber 20, is a pipe 26, to which is connected a vacuum pipe 27 that leads to certain vacuum breaking mechanism 28 (operated by the die press mechanism) and from which mechanism 28 a flexible vacuum pipe 29 leads to the strip lifters 30. The

construction and operation of the strip lifters is well understood and requires no detailed description so far as this invention is concerned.

From the compression side 18 of the cylinder leads a compressed air pipe 31, which is carried to a point adjacent the dies 6, at which placea nozzle 32 is secured to the compressed air pipe and is held in position in front of the dies by a standard or other support 33 which may be secured to the press body. The discharge orifice of the nozzle 32 isrestricted in size and is directed toward the dies as shown, and supplies blasts of air which blow the stamped articles away from the dies.

In the operation of the device, the crank shaft 9 reciprocates the punches 6 and also reciprocatesthe piston 14 through the instrumentality of the bracket 16 and plston rod 15. The piston travels back and forth in the cylinder making one stroke for each revolution of the crank shaft. On its stroke in the direction of the arrow at, in Fig. 2, any air contained in the vacuum end 17 of the cylinder is forced out through the port 24 and air is drawn into the compresslon end 18 of the cylinder. On the return stroke of the piston. the air in the end 17 of the cylinder is rarefied and a partial vacuum is produced in said cylinder, the vacuum chamber, vacuum pipes 27, 29, and strip lifters 30, whereby the strips may be lifted by said strip lifters. Simultaneously the air contained in the compression end 18 of the cylinder is forced through the com-.

pressed air pipe 31 and discharged through the discharge orifice of the nozzle 32, and the blast of air issuing from said nozzle is directed against the article which has been stamped out of the strip. In the form of the invention illustrated in the drawin the piston 14 is moved in the direction 0 the arrow at, during-the last half of the down stroke of the crank 8' and during the first half of the up stroke of the crank, during which time air enters the compression side of the cylinder through the nozzle 32 and air pipe 31. During this portion of the down and up movement of the punchthe latter punches the strip and moves upward and away therefrom. During the last half of the up stroke of the crank 8 and first half of the down stroke of the crank the piston ltis moved toward the compression end of the cylinder, thereby forcing the accumulated air out through the air pipe and nozzle, and because of the relatively narrow discharge orifice of the nozzle the air is compressed in the cylinder and air pipe and issues from the nozzle in the form of a strong blast of air. This blast of air takes place while the punch is traveling upward and downward after having left the work ing is thereby blown away from the dies, which makes it possible for the crank shaft to revolve with comparatively high speed thereby greatly increasing the capacity of the press.

More or less variation of the exact detalls of construction is possible without departing from the spirit of this invention I desire, therefore, not to limit myself to the exact form of the construction shown and and before it again reaches it. The stampdescribed, but intend, in the following claims, to point out all of the invention disclosed herein.

I claim as new, and desire to secure by Letters Patent:

1. In a pneumatic device for the strip lifters and dies of die presses, a pneumatic cylinder, a piston traveling therein, plston actuating means, a Vacuum chamber at one end of said cylinder, inlet and outlet valves therefor, a vacuum pipe leading from said vacuum chamber to the strip lifters, and a compressed air pipe leading from the opposite end of the cylinder to the dies and having a nozzle directed towards said dies.

2. In a pneumatic device for the strip lifters and dies of die presses, the combination with a press body, and a die actuating crank shaft journaled thereon, of a pneumatic cylinder supported by said press body, a piston reciprocating in said cylinder, operative connections between said piston and crank shaft, a vacuum chamber at one end of said cylinder, inlet and outlet .valves therefor, a vacuum pipe leading from said vacuum chamber to the strip lifters, and a compressed air pipe leadin from the other end of the cylinder to the %ies of the die press and provided with a nozzle 'directed toward said dies.

3. In a pneumatic device for die presses,

ber to the strip lifter, and a compressed air pipe leading from the other end of the cylinder to a place adjacent the dies and having a nozzle'directed towards said dies.

4. In a pneumatic device for die presses, the combination with a die press body, a pneumatic strip" lifter, dies, a pitman, and

and arranged to actuate said pitman, of a pneumatic cylinder rocka'bly mounted on said die press body, a piston reciprocating in said cylinder, a piston rod connected to said piston, an'arm connecting said piston rod to said pitman, a valve controlled vacuum chamber at one end of said cylinder, a vacuum pipe leading from said vacuum chamber to the strip lifter, and a compressed air pipe leading from the other end of the cylinder to a place adjacent the dies and having a nozzle directed towards said dies.

CHARLES D. MoD ONALD.

a crank shaft journaled in said press body

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