US1927499A - Hollow piston hammer - Google Patents

Description

Sept. 19, 1933. G, M NELL ET AL HoLLow PIsToN HAMMER Filed March 2o, 1930 IN V EN TORS` Gascn/e /14 /Ve// foward 14./ fiere/75 of. @www ATTORNEY.

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Patented Sept. 19, 1933 UNITED STATES HOLLOW PISTON HAMLIER Gustave M. Nell and Edward W. Stevens, Detroit. Mich., assignors to Chicago Pneumatic Tool Company, New York,

New Jersey N. Y., a. corporation of Application March 20, 1930. Serial No. 437,358

14 Claims.

This invention relates to percussive machines and more particularly to stationary machines adapted for metal drawing and similar operations.

One object of the invention is to provide a percussive machine for passing the work axially therethrough. Another object is to protect the operative parts of the machine from interference by the work while facilitating its passage. Other objects will be apparent from the detailed description which follows.

The invention involves a percussive machine having a hollow piston with the work passing axially therethrough. The piston may be arranged to reciprocate between the inner and outer walls respectively of two cylinders coaxially mounted one within the other. The work is acted upon by a die which is subjected to the blows of the piston and when an inner cylinder is used the work passes through the bore -of the latter. Suitable means, which may include the die, support the cylinders fixedly in proper relation to one another to insure theV functioning of the percussive motor. Y

In order to illustrate the invention concrete embodiments thereof are shown in the accompanying drawing in which:

Fig. 1 is a longitudinal sectional view somewhat diagrammatic in character of a fluid pressure valveless percussive tool; and

Fig. 2 is a similar longitudinal sectional view showing atvalved fluid pressure hammer.

Both forms of the invention disclose a percussive machine adapted to pass the work in solid extended form, such as a metal rod, axially there-l through while subjecting the same to drawing' or similar operations through the vibratory action produced by a high speed percussive member upon a die in engagement with the work.

In the form shown in Fig. 1 a cylinder 3 has reciprocably mounted therein a hollow or annular piston 4 for imparting blows directly to a hollow or annular die 5 also telescoping at least partially into cylinder 3 and movably supported by the same. Motive fluid is admitted continuously through inlet port 6 in cylinder 3 to an annular chamber in piston 4 providedby groove or recess 'when die 5 strikes abutment 15.

ent invention. Fig. 1 shows the piston at the beginning of its rearward or return stroke. The pressure fluid enters the inlet port 6 and passes by way of annular groove 7 and passage 9 to the front end of the piston chamber. The piston 4 is thereby driven rearwardly, the exhaust air at the rear end of the chamber passing through exhaust port 10. During the rearward movement of the piston, port 10 becomes covered, thereby effecting the compression of uid at the rear end of the chamber, but theV piston continues until some time after the annular groove 7 has cut off the supply of motive huid from the passage 9 and has diverted the iiuid through passage 8 to the rear end of the chamber. When the port 11 is uncovered, the pressure at the front end of the piston chamber suddenly drops, and the piston is caused to move in the forward direction. The forward movement of the piston is similar to the rearward movement and will continue until the port 10 is uncovered.Y

In order to protect the hammer mechanism against interference by the work passing axially through the machine an inner cylinder 12 is pro' vided coaxially disposed within outer cylinder 3 and having sliding engagement with the inner surfaces of piston 4 and die 5. The latter may be utilized to maintain cylinders 3 and l2 in proper co-axial relation at one end. Suitable means for the same purpose at the opposite end may comprise a radial flange on one of the members of greater lateral extent than the piston chamber. In the form shown inner cylinder l2 has flange 12a which seats in an annular recess 3a in cylinder 3 but projects beyond the latter to be en" gaged by a perforated back head 13.` In order that the latter may be accurately centered to provide anaxial passage for the work it may have an annular recess 13a receiving the projecting portion of flange 12a. Side rods 14 may be utilized to hold back head 13 in place. These rods may serve resiliently to support a transverse retainer abutment 15 for limiting the movement of die 5 in the machine and to prevent its accidental ejectment therefrom. To this end rod 14 may have sleeved. thereover spacers 16 interposed between abutment 15 and perforated ears 3bA on outer cylinder 3. Coil springs 17 on rods" 14 beyond abutment 15 and backed by securing members, such as nuts 18, prevent breakage of parts An annular buffer member 19 of leather, or rubber compound, may be suitably mounted as in a groove on abutment 15 to take the 'direct blow of die 5.

In the modification shown in Fig. 2 a machine of less overall length is provided in which the distribution of motive fluid to effect the reciprocations of hollow piston 20 is controlled by an automatically-thrown distributing valve 2l. While the valve may be of any suitable or known type, it is herein disclosed as a ring valve. Valve 21 is supported in a valve block comprising a case 22 and cylinder closure disc 23, the latter having a passage 24 opening directly into the rear end of the piston chamber and also a portion of passage 25 leading through the wall of outer cylinder 26 to the front end of the piston chamber. Flange 27a on inner cylinder 27 serves as the lid for the valve case and is engaged directly by perforated back head 28 which is secured to outer cylinder 26 by a threaded connection and provides the inlet 29 for the motive fluid. Valve 21 distributes the motive fluid in alternation to passages 24 and 25 to reciprocate piston 20 in a manner well known to those skilled in the art. The incoming motive fluid is conducted from inlet 29 through radial openings (not shown) in the case 22 to the top and bottom peripheral surfaces of the ring valve 2l. In the position shown in Fig. 2, the valve is on its upper seat thereby closing the passage 25 but permitting fluid to flow through passage 24 to the rear end of the piston chamber. The fresh supply of motive fluid now engages a larger area of the bottom of the valve than the tcp of the same, and thereby tends to hold the valve in the position shown. The piston 20 is caused to move forwardly pushing the exhaust air in the front end of the piston chamber through outlet 31 until this outlet is covered by the piston 20. Thereafter, continued forward movement of the piston compresses the iluid in the forward end of the chamber until a sufficient pressure is reached to throw the valve 21 downwardly due to the pressure transmitted through passage 25 to the front end of the piston chamber and forces the piston rearwardly until the valve is thrown back to the position shown in Fig. 2. Outer cylinder 26 has atmospheric piston-controlled vents 30 and 31 for the opposite ends of the piston chamber and long perforated ears through which extend bolts 32 with spacers 33 thereon for supporting retainer abutment 34 for movable die 35. Retainer abutment 34 conforms in all respects to abutment 15 of the first form of the invention having springs 36 supporting the same and a cushion ring 37 to receive the direct blow of die 35. In operation the work in the form of a bar, rod, or tube to be extruded or reduced by die 5 or 35, enters the machine through the bore in the retainer abutment 15 or 34, it being understood that the Work may be forced through the machine or the machine moved over the work while the latter is heldstationary. In either instance, as the Work enters the die 5 or 35 the percussive motor is operated, and the blows rained upon dies 5 and 35 by the reciprocating hammer piston 4 or 20 produces rapid action of the die upon the work so that the finished work may pass through the machine with a steady continuous movement. The rapid action of the machine is enhanced by the mounting of die 5 or 35 whereby slight movement of the same Within the machine in an axial direction is permitted. Inner cylinder 12 or 27 serves as a guide for the work and maintains it out of any possibility of contact with percussive member 4 or 20 so that the machine cannot be injured by its accidental displacement relative to the work.

While the invention has been herein disclosed in what are now considered to be preferred forms,

2. A percussive machine having a hollow piston I reciprocable therein, a die movably mounted in said machine to receive the blows of said piston, and means for guiding the work acted upon by said`die axially through said machine and piston but maintaining it out of contact with said piston.

3. A percussivev machine having a hollow piston reciprocable therein, a die movably mounted in said machine to receive the blows of said piston, resilient means for limiting the movement of said die in one direction, and means for guiding the work acted upon by said die axially through said machine but maintaining it out of contact with said piston.

4. A percussive machine comprising tubular members in coaxial relation providing a central passage therethrough and an annular chamber therebetween, a hollow piston reciprocable in said chamber, and means subjected to the blows of said piston for acting upon work passing through said passage.

5. A percussive .machine comprising tubular members, means maintaining said members in fixed co-axial relation to provide a central passage therethrough and a chamber therebetween, a piston reciprocable in said chamber, and a die supported by one of said members in position to receive the blows of said piston for working upon material passing through said passage.

6. A percussive machine comprising tubular members in co-axial relation providing a central passage therethrough and an annular chamber therebetween, a hollow piston reciprocable in said chamber, means subjected to the blows of said piston for acting upon work passing through said passage, and means maintaining said members in fixed co-axial relation including a flange on one of said members.

7. A percussive machine comprising tubular members, means maintaining said members in fixed co-axial relation to provide a chamber therebetween including a flange on one of said members of greater lateral extent than said chamber, a piston reciprocable in said chamber and a die for receiving the blows of said piston.

y8. A percussive machine comprising tubular members, means maintaining said members in fixed co-axial relation to provide a chamber therebetween including a radial flange on said inner memberof greater extent than said chamber, a piston reciprocable in said chamber, and a.die for receiving the blows of said piston.

9. A percussive machine comprising two cylinders co-axially mounted one within the other,

means maintaining said cylinders in xed relation including a ange on one member, an annular piston reciprocable in the chamber provided between said members, a die movably supported by both cylinders for receiving the blows lof said piston, and resiliently mounted retainer abutment for limiting the outward movement of said die. l

10. A percussive machine comprising tubular members, means maintainingsaid members in xed co-axial relation to provide a chamber therebetween including a radial ange on said inner member of greater extent than said chamber, a back head engaging said harige, a piston reciprocable in said chamber, and a die for receiving the blows of said piston.

l1. A iluid pressure percussive machine comprising two cylinders co-axially mounted one within the other to provide a piston chamber therebetween, an annular piston reciprocable in said chamber, means for distributing pressure fluid to the opposite ends of the piston chamber to reciprocate said piston, means at one end of said machine for maintaining said cylinders in proper spaced relation, a die at the opposite end of said machine for maintaining the spacing of said cylinders and for receiving the blows of said piston.

12. A iluid pressure percussive machine, comprising two cylinders co-axially mounted one within the other to provide a central passage therethrough and a piston chamber therebetween, an annular piston reciprocable in said chamber, a valve block at one end of said machine having ports and passages leading to the opposite ends of said chamber, an automatically-thrown distributing valve for controlling said ports and passages, one of said cylinders having a radial flange forming a lid for said valve block, and a die at the opposite end of said machine for receiving the blows of said piston and for maintaining the coaxial relation of said cylinders.

13. A fluid pressure percussive machine comprising two cylinders co-axially mounted one within the other to provide a central passage therethrough and a piston chamber therebetween, an annular piston reciprocable in said chamber, a valve block at one end of said machine having ports and passages leading to the opposite ends of said chamber, an automatically-thrown distributing valve for controlling said ports and passages, said inner cylinder having a radial flange forming a lid for said valve block, and a die at the opposite end of said machine for receiving the blows of said piston.

14. A iiuid pressure percussive machine comprising two cylinders co-axially mounted one within the other to provide a central passage therethrough and a piston chamber therebetween, an annular piston reciprocable in said chamber, a valve block at one end of said machine having ports and passages leading to the opposite ends of said chamber, an automatically-thrown distributing valve for controlling said ports and passages, said inner cylinder having a radial ange forming a lid for said valve block, a back head secured to said outer cylinder and engaging said flange for maintaining the parts at the valve end of the machine in proper assembled relation, and a die at the opposite end slidably engaging and spacing both cylinders for receiving the blows of said piston.

GUSTAVE M. NELL. EDWARD W. STEVENS.

CERTIFICATE OF CORRECTION.

Patent No. l, 927, 499.

September 19, 1933.

GUSTAVE M. NELL, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Page 3, line 88, claim 13, after "piston" insert "and .for maintaining the co-axial relation of said cylinders"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of October, A. D. 1933.

(Seal) F. M. Hopkins Acting Commissioner of Patents.

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