US2969871A - Method of operating a high speed shell forging press - Google Patents

Description

1961 P. H. DANLY 'ETAL 2,969,871

METHOD OF OPERATING A HIGH SPEED SHELL FORGING PRESS Filed Aug. 10, 1951 5 Sheets-Sheet 1 INVENTORS PH/LO H. DflNLY was/L GEOEGEFF Jan. 31, 1961 P. H. DANLY ETAL 7 2,969,871

'METHOD OF OPERATING A HIGH SPEED SHELL FORGING PRESS Filed Aug. 10, 1951 5 Sheets-Sheet 2 v INVENTORS PH/LO H. DANLY L Wis/L GEOPGEFF :3 BY

A TTORNEY Jan. 31, 1961 P. H. DANLY ETAL I METHOD OF OPERATING A HIGH SPEED SHELL FORGING PRESS Filed Aug. 10, 1951 5 Sheets-Sheet 3 PH/LO H DQA/LY VHS/L GEORGEFF HTTOENEY 5 Sheets-Sheet 5 Jan. 31, 1961 P. H. DANLY ETAL METHOD OF OPERATING A mcu SPEED SHELL FORGING PRESS Filed Aug. 10, 1951 h I HI.

4TTOPNEY METHOD OF OPERATING A HIGH SPEED SHELL FORGING PRESS Philo H. Danly, Hinsdale, and Vasil Georgeff, La Grange Park, Ill., assignors to Danly Machine Specialties, Inc., Chicago, Ill., a corporation of Illinois Filed Aug. 10, 1951, Ser. No. 241,272

'1 Claim. (Cl. 2058) Our invention relates to a high speed shell forging press and more particularly to a press for forming elongated hollow articles such as cartridge cases and the like by a drawing operation.

Cartridge cases are formed by successive drawing operations. A flat blank is first cupped. The cup is then successively elongated in the plurality of drawing operations each of which elongates the shell until the final article is produced. In a typical case for a three-inch fifty-caliber cartridge case a flat plate is cupped in a press which requires a sixteen-inch stroke. The first draw requires a twenty-inch stroke. The second draw requires a twenty-five-inch stroke. The third draw requires a thrity-seven-inch stroke, and the final draw requires a fifty-two-inch stroke. It is known to the art that there are intermediate annealing operations between the draws. It will be appreciated that to provide a two hundred and fifty-ton press, for example, with a fifty-two-inch stroke, excessively large gearing will be required and that inasmuch as there is a critical drawing speed the punch is limited in its velocity of travel such that not more than about four strokes per minute can be employed. The large stroke is necessitated by the requirement that the punch enter the elongated shell of the workpiece produced by the previous draw to move to the position to begin the drawing operation. A press with a fifty-twoinch stroke will be a large and cumbersome machine which is expensive to build. These considerations make it substantially unfeasible to draw cartridge cases and the like by mechanical reducing or drawing presses known to the art and have made it necessary to use hydraulic presses. Hydraulic presses, on the other hand, are comparatively slow in their operation since the speed of the ram under the influence of hydraulic fluid pressure must necessarily be slow to obtain the mechanical advantage required. It will be seen, therefore, that no feasible method is known to the art for the rapid drawing of cartridge cases and the like.

One object of our invention is to provide a mechanical drawing press capable of comparatively rapid operation of about ten strokes per minute or more.

-Another object of our invention is to provide a mechanical drawing press which is inexpensive in construction and of remarkably small size in view of the large stroke through which it is capable of acting.

A further object of our invention is to provide a mechanical drawing press for forming cartridge cases in which the drawing starts at a comparatively low speed and maintains a drawing speed less than the critical speed throughout the entire stroke.

Other and further objects of our invention will appear from the following description.

In general, our invention contemplates the provision of a main slide adapted to be reciprocated with simple harmonic motion through a driving train energized from a first prime mover. The main slide carries an auxiliary slide and a second prime mover adapted to drive a drivin g train of gears in predetermined phase relation with United States Patent F Patented Jan. 31, 1961 ICC the main slide. The punch for the drawing operation is carried by the auxiliary slide. The arrangement is such that the auxiliary slide will drive the punch downwardly and dwell. This dwell is achieved by the disengagement of the auxiliary slide clutch. As soon as the auxiliary slide stops its downward motion the main slide will commence its motion carrying downwardly the auxiliary slide and the punch along with the main slide. After the draw has been performed the auxiliary slide is again engaged with its drive train so that the punch will move upwardly at a high rate of speed due to the composite motion imparted to it both by the auxiliary slide and the main slide.

In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

Figure 1 is a perspective view of a high speed shell forging press showing one embodiment of our invention.

Figure 2 is a sectional elevation drawn on an enlarged scale viewed generally along the plane 22 of Figure 1.

Figure 3 is a sectional view taken along the line 3--3 of Figure 2.

Figure 4 is a sectional view drawn on an enlarged scale taken along the line 44 of Figure 2 Figure 5 is a phase diagram showing the phase relationships and amplitudes of motion of the various parts of our press in comparison with a press having a length of stroke equal to the stroke of both slides.

Figure 6 is a view showing the position of the punch, the workpiece and the stationary die before the commencement of the draw and showing the elongation achieved during the draw in the phase diagram of Figure 5.

Figure 7 is a motion diagram showing the motion of the main slide and auxiliary slide of our press for the second draw corresponding to the phase diagram shown in Figure 5.

More particularly referring now to the drawings, a press frame 10 may be of any suitable construction and supports a bed 12 on which the stationary die is supported. The movable die is carried by the auxiliary slide 14 which is mounted for reciprocation within the main slide 16 which is mounted for reciprocation within the frame 10. Suitable gibs 18 are carried by the frame for guiding the main slide and suitable gibs 20 are carried by the main slide for guiding the auxiliary slide 14. The guiding arrangement can best be seen by reference to Figure 4.

A prime mover such as an electric motor 22 is carried by the frame 10 and adapted to drive a main flywheel 24 through V-belts 26. A clutch in housing 28 is adapted to drivingly engage the flywheel 24 with the main drive shaft 30 of the main slide driving train. The drive shaft 30 is normally immobilized by a brake within housing 32. The arrangement is such that when it is desired to frame 10. Each crankshaft is formed with a crankpin 46 around which is positioned a pitman 48. The lower end of each pitman 48 is pivotally secured to the main slide 16 by means of a pin 50. The. arrangement is such that The press control is governed by a timing the rotation of the cranks will reciprocate the main slide 16 with simple harmonic motion. I

Secured to the main slide and supported thereby in any suitable manner we provide a second prime mover such asan electric motor'52 whichcontinuallydrrves a flywheel 54 through V-belts 56. A'clutch is positioned within housing 53. This clutch is adapted to engage the flywheel with the shaft 58*supported for rotation upon the main slide in any suitable manner. A brake housing 60 is carried by the main slide and is adapted when the'brake therein is engaged to immobilize the shaft 58. Thearrangement is similar to the main driving arrangement andis well known in the art. It is such that when the clutch is engaged the brake isreleased so that the flywheel-driven by the motor 52 will rotate-the shaft 58. A worm 62 is secured to the shaft 58 for rotation-therewith and engages 'a worm gear 64 formed with a crank 66 having a crankpin 68. A-bell crank 74 is pivotally mounted upon a shaft 70 carried bythe main slide. One arm 72of the bell crank isconnected by 'pin 76 through link 78 to the crankpin 68. The other arm 80 of the bell crank is connected toa link 82 by a pin84. The other end of link 82 is connected by pin 84' to the auxiliary slide 14. The weight of the main slide and associated parts iscounterbalanced by a pair of aircylinders 86 carried by the frame 10.

As can be seen by reference to Figure l, the Workpieces are fed to Working positionby a rotary-feed plate 9 actuated through an arm 92. The feed forms no part of the instant specification and is therefore not described in detail.

Referringnow to Figure 6, the punch 100 is carried by the auxiliary slide. The workpiece IUZ-iscarriedby the dial feed plate 90 in a guide bushing 10.4. Thedie 106 is carried by a back-up plate 108. A' retaining plate 110.retains the die 106. A stripper plate 112 is provided. For the second draw the auxiliary slide will move through a distance often inches and the main slide will move through a distance of fifteen inches. For the third draw the auxiliary 'slide will move through a distance of seventeen inches andthe main slide will move through a distance of twenty inches. the auxiliary slide will move through a distance of twenty-four inches and the main slide will move through a distance of twenty-eight inches.

Referring now to Figure which shows a graphic comparison between a complete 360 cycle of a conventional mechanical press, represented by the outer circle, anda complete cycle according toa press of the instant'invention, as represented'by the twoinner circles,

each circle representsthe angular position of thecrank at any designatedpoint of the stroke. It will be readily seen in Figure 5 that the drawing portion of the downmidstroke when the punch has reached its .maximum' speed. This is necessarily so since in any reciprocating slide the maximum linear speedis reached-at midstroke, assuming a constant speed of crank rotation. 'It will-be further apparent, as can more readily be appreciatedzby reference to Figure 7, that in the instantinvention the inherent disadvantage of the conventional mechanical press is eliminated since the draw actuallystarts at zero speed, that is, at the top of itsstroke. The upper small circle A represents the rotation of the crankpin 68 of the auxiliary slide. The lower circle M representsthe rotation of the crankpin 46. For the seconddraw the diameter of the circle A will be'ten'inches and the diameter of the circle M'will'be fifteen inches. For the final vdraw the diameter ofthe circle A would be :twenty-four inches and the diameter o'fthe circle M would be twentyeight inches. It will be seen that the sum of thediameters of the circles A and M, that-is, the strokes of the For the final draw accuser into position under the punch 100 the clutch for the auxiliary slide is engaged while its brake is released. The auxiliary slide will then travel downwardly entering the punch into the workpiece 102. While this takes place the main slide rests at its top dead center, as can readily be seen by reference to Figure 7. At this point the auxiliary slide clutch is disengaged and the main 4 slide clutch is "engaged. The main slide then moves V back-up plate of the die.

downwardly carrying with it the auxiliary slide and the punch 'and performs the drawing operation. It will be noted that the motor for the auxiliary slide is comparatively small andvlight as 'no function other than a positioning one is performed during the entering portion of the stroke. By reference to Figure 3 it will be seen that links 80 and 82 are extremely stout and at their bottom dead center form a straight angle. The entire thrust of the punch is transmitted from link 82 to link 80 to the stout pin 70 which is carried by the main slide. Link 78 forms a straight angle with link 66 and is maintained in this position through the worm wheel 64 and the worm 62, the shaft 58 which carries the worm "62 being immobilized by the brake 60. When the main slide moves "downwardly it will draw with the punch being locked at its bottommost position in the manner just described. After the draw an overtravel is provided to push the shell formed by the draw through the ,die. It will beseen by reference to Figure6 that the .stripper plates 112 are immediately below the As the shell is-pushed through the die the stripper plates yield, as is well known to the art, and latch the finished shell in the lowermost position while the ,punch is being pulled out of the shelland die during the stripping operation. As soon as the stripping operation hasbeen completed and the punchis free of the shell at :about 240 of motion of the main slide the main slide starts returning. Slightly before this at about 230 ofmotion of themainslide the auxiliary clutch has been engaged so that both the main slide and the auxiliary slide move upwardly giving a composite upward motion asshown in Figure 7. At about 270 ofmotion of the main slide the dial feed will commence to feed 'the next workpiece and the cycle will repeat.

By reason of the rapid return due to the composite motion of the auxiliary slide and the main slide and the comparatively rapid downward motion of the auxiliary slide the speed of operation of the entire press can be greatly increased. From the normal four strokes per minute, which is the-maximumpossible with a single slide of conventional construction, we are enabled to increasethe number of strokes to ten or .more. By reference to .Figure 7 it will be seen that the draw starts at .a comparatively low speed and a safe drawing speed is notexceededdue to.our combination. The'composite curve-of motion as shown in Figure 7 of thepunch will be seen to comprise first-arapid motion caused by the auxiliary slide alone, after which the auxiliary slide dwells, then .a motion due to the motion-of the main slide alone and then a composite motion due to incremerits inan upward direction contributed by-both the motion of the auxiliary slide and the main slide.

It will be seen that we have accomplished the objects of our invention. We have provided amechanical drawing ,press capable of comparatively rapid .operation .of about ten strokes --per minute or morewhich is inexpensive in construction andof remarkablysmallisizeifor .the largestroke through 'which ;it is-capable of acting. We have provided a mechanical drawing'pressin which the drawing starts at a comparatively low speed and maintains a drawing speed less than thecriticalspeedthroughout the entire stroke.

It will be understood that certainfeatures and subcombinations are of utility and may beemployed without reference to other 'features and subcornbinations. This is contemplated 'byandis within the scopeof our claims. It isturthercbvious that various changes may '"bemade in details within the scope of our claims without departing from the spirit of our invention. It is therefore to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, what we claim is:

A method of drawing metal in a power press having a main slide and an auxiliary slide mounted on said main slide including the steps of placing a blank in the power press, extending the auxiliary slide to its bottom dead center position from an upper position, locking the auxiliary slide in its extended position, then reciprocating References Cited in the file of this patent UNITED STATES PATENTS Fenton Mar. 28, 1905 Bohn Jan. 2, 1945 Byerlein June 19, 1956

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