US2263680A

US2263680A - Drop hammer

Info

Publication number: US2263680A
Application number: US152544A
Authority: US
Inventors: William H J Fitzgerald; Reginald P Fitzgerald
Original assignee: Pneumatic Drop Hammer Co
Current assignee: Pneumatic Drop Hammer Co
Priority date: 1937-07-08
Filing date: 1937-07-08
Publication date: 1941-11-25
Anticipated expiration: 1958-11-25

Description

W.`H. J. FITZGERALD fET AL.

Nov. 25, 1941.

lDROP HAMMER Filled July s, vlsfsv 6 Sheets-Sheet l Reginald F. Fggerod w..H. J. FlTzGEALD ETAL 2,263,680

DROP HAMMER Filed July 8, 1957 6 Sheets-Sheet 2 Reginald F? Fggerfod NOV 25, 1941- w. H. J. FITZGERALD ETL I 2,263,680 y DROP HAMMER Fild July s, 1937 e sneaks-sheet :s

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m m Wm wm. .ww m w11 f N. ww m lnvenrors. .Q Fi'fggeruld egnald F? Fggeral-d William H ATTy s.

Npv. 25,1941# w. H. J. FITZGERALD ETL i 2,253,630

DROP HAMMER Filed Julyl 8, 1937 6 Sheets-Sheet 4 NOII- 25, 1941- w. H. J. Fwzsl-:RALD l-:T AL

DROP HAMMER Filed July 8, 1957 6 Sheets-Sheet 5 VViH Reginald F? Fggerold A'TyS.

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N0 25, 1941 w. H..J. FlTzGL-:ALD ET A17 2,263,630

i DROP HAMMER Filed July 8, 1957 6 sheets-sheet e mm om T NC 8Go ,mma 1F. J. H m .m W

'ATB/S. I

Patented Nov. 25, 1941 2,263,680 Dnor HAMMER.

William H. J Fitzgerald and Reginald P. Fitz- `gerald, Braintree, Mass., assignorsto Pneumatic Drop Hammer Company, Roxbury, Mass.,-a cor.- poration of Massachusetts Application July 8, 1937, Serial No. 152,544

l(Cl. 11B-.38.)

8 Claims.

This invention relates to improvements in drop hammers and the principal object of the invention is to provide a drop hammer construction in which the hammer is reciprocably mounted in guides in a suitable frame, With means for `lifting the ham-mer, and means for releasing the hammer when raised to `permit it to drop and having means for insuring equalization of movement of the guided portions of the 'hammer throughout the lifting movement thereof.

In usual drop hammer constructions the Weight of the `hammer is substantially uniformly distributed with respect to a central vertical axis and the ends of the hammer are guided in vertical ways or upon vertical columns. The vertical lifting force is applied in or approximately in the direction of the vertical axis of the center of gravity and as a consequence the hammer may be lifted and dropped without any substantial binding action between the ends of the hammer and the guides therefor.

Where, however, the hammer is unsymmetrically weighted, as for example by the attachment thereto of one ofthe members of the complementary dies, in which the Weight of one portion of the die, which is carried by the hammer, very considerably exceeds the weight of other portions of the die, the hammer will tilt and bind in its guides when lifted by force `which is applied -at a point or points not in the vertical axis of the center of gravity, so that the hammer will not dropl properly withrespect to the complementary die, orwill so bind on the guides as to prevent operation of the hammer at all.

A11-object of vthe present invention is to provide means operable during the lifting movement of the hammer to transmit a lifting force or lifting forces, which are applied to the hammer, at a point or points remote `from the vertical axis of the center of gravity which will equalize the rates of movement of the guided portions of the hammer in such manner that the hammer will be lifted vertically without binding upon the guides and which also will insure proper maintenance of the position of the hammer during the dropping movement thereof.

One of the principal objects of the invention is to provide a drop hammer construction in which the hammer and anvil or complementary dies carried respectively by the hammer and anvil are of much greater area and in which drop hammers of muchgreater weight may be employed than in previous vdrop hammer constructions, such, for example, as drop hammers and diespflor shaping fenders and other parts of automobiles,

metal aeroplane wings, or other large areas of metal or the like, and particularly those in which the dies are-of irregular contour and unsymmetrically `distributed weight.

A further object-of the invention is to provide a drop hammer construction in which the hammer is lifted by a plurality of lifting forces applied to different-portions of the hammer, with means for so transmitting portions of such lifting forces that the resultants thereof will raise the hammer vertically anduniformly throughout its e-ntire area.

A further object of the -invention is to provide a drop `hammer construction of the character above specified in which the lifting force or forces are applied to the hammer by 4fluid pressure operated means acting upon the hammer at a point or points remote from the vertical axis of the center of gravity of the ham-mer, in combination with means for so distributing the lifting `force or forces as-to insure uniform rates of movements of the guided portions of the hammer which will avoid vbinding of the hammer upon the guides.

Another object-of the invention is `to provide a drop hammer construction in which the hammer is pushed upwardly by `a iluidpressure operated means Yactingl upon vthe en d portions of the hammer.

Anotherfeature of theinvention relates `to 4novel Vfluid pressure actuated mechanism for controlling the admission of fluid simultaneusly to the cylinders of the lifting mechanism.

Another object of the invention is to provide a drop hammer for die forging in which the hammer die is cast upon the hammer and amethod for producing such a construction.

Another object of -the invention is `to provide pneumatically operable means for effectively cushioning ythe-upward movement Yof the Yhammer when lifted which will prevent abrupt arrest of the hammer and consequent jarring which would tend to injure the structure.

These land other objects and `features of the invention will morev vfully appear Yfromfthe iollowing description and the accompanying drawings, andwill be particularly pointed out inthe claims.

V,Preferred embodiments of `the invention are illustrated in the accompanying drawings, -=in which:

Fig. -1 ;is a fron-t elevation of a drop 'hammer embodying -the invention in which `the hammer is lifted by two `pneumatically operated cylinders and pistons, `the'piston rods of which lapply lifting `forces at the ends of 'the ihammer, the

mechanism for equalizing the movements of the ends of the hammer being omitted.

Fig. 2 is a similar View showing the frame construction in dotted lines, but illustrating in full lines the hammer, the lifting mechanism therefor, and the equalizing mechanism for insuring equal rates of movement of the ends of the hammer;

Fig. 3 is a plan view of the construction shown in Fig. 2, the frame being illustrated in dotted lines;

Fig. 4 is an end elevation of the construction illustrated in Fig. 2, the frame being shown in dotted lines;

Fig. 5 is a detail elevation, viewed from the rear, showing the valve controlling mechanism for admitting fluid under pressure to the lifting cylinders;

Fig. 6 is a detail elevation of the construction shown in Fig. 5, Viewed from the left toward the right;

Fig. 7 is a detail vertical sectional View showing the admission and exhaust valves in their relative positions for admission of fluid under pressure to the lifting cylinders;

Fig. 8 is a similar detail sectional view showing the admission and exhaust Valves in their relative positions for release of fluid under pressure from the lifting cylinders to permit the hammer to drop; and,

. Fig. 9 is a detail View showing the contour of the adjustable exhaust port for regulating the rate at which fluid under pressure is released from the cylinders thereby controlling the speed of descent of the hammer;

Fig. 10 is a detail view, partially in vertical section, on line Ill-I0 Fig. 11 of a drop hammer construction illustrating the manner in which the hammer die is cast upon a hammer of the type illustrated herein; and,

Fig. 11 is a plan View of the hammer construction illustrated in Fig. 10,

The drop hammer construction as illustrated in Fig. 1 comprises a heavy integral bed I supporting an anvil 2 upon which an unsymmetrical die 3 is mounted and a frame comprising pairs of

vertical end standards

4 and 5, each pair being integrally connected at their upper ends and each standard is provided With a pair of guides 6 and I for the hammer. The pairs of standards are connected at their upper ends by a transverse beam 8.

The hammer 9 is provided with extended guiding members I0 and II which are complementary to and slidably mounted upon the guides 6 and 'I respectively. The preferred form of hammer, which is illustrated herein as adapted for dieshaping long articles of considerable width, is of rectangular form and is provided with a central upwardly extending boss I2 with vertical webs I3 and I4 extending radially therefrom to the guides I Il and I I and other webs I5 extending to the edge of the hammer at right angles to the longitudinal axis thereof. The ends of the hammer are provided with extensions I6 and I'I which project outwardly between and beyond the respective pairs of guides I0 and II and the lifting forces for raising the hammer are applied to such extensions. The hammer as illustrated has secured to it a die I8 which is complementary to the anvil die 3 and as will be observed is of much greater weight at one end than the other.

The complementary dies may be of any suitable form and shape and may be of steel, but

where a limited number of parts are to be shaped the dies may be made of relatively soft metal, usually of different hardness, such as an anvil die of Zinc or bronze composition and a complementary die of lead or other relatively softer metal.

The anvil die may be constructed by forming a matrix of plaster of Paris or the like and shaping the operating face to the desired contour and ornamentation. The harder metal for the anvil die may then be cast upon this matrix. When the matrix is removed the die may be turned over and suitably secured to the anvil.

By the present invention the hammer die may then be cast directly upon the hammer itself by a method hereinafter to be described.

By reason of this invention a hammer die is produced which is complementary in all respects to the anvil die and adapted to register accurately with the same during the period of its use. Such dies may be used for shaping relatively ductile metal, such as aluminum, or relatively thin sheets of steel and the like for a more or less limited number of times. The dies constructed in this manner are used particularly in the production of large die-shaped pieces where a limited number of different sizes or different contours are frequently required.

In such drop hammer constructions the vertical axis of the center of gravity of the hammer is ordinarily remote from the central vertical axis of the hammer and inasmuch as one end of the hammer is of greater Weight than the other end or portion of the hammer, there will be a tendency of the hammer to bind upon its guides as the hammer is lifted, by a force or forces applied to the hammer at points out of alinement of the vertical axis of the center of gravity of the hammer.

The particular drop hammer construction il lustrated herein is designed for the shaping of large areas of metal and the hammer may be of several tons weight. In order properly to lift such a hammer pneumatically operated means are preferably provided for simultaneously lifting both ends of the hammer, with means for equalizing the rate of movement of the guided portions of the hammer which will prevent binding of the hammer upon its guides. The lifting mechanism illustrated comprises a pair of vertical pneumatic cylinders I9 and 20 which are located at the ends of the base and are provided with pistons having respectively piston rods 2| and 22, the upper ends of which engage the under faces of the extensions I6 and I'I of the hammer. Suitable 'means hereinafter to be more fully described are provided for simultaneously admitting fluid under pressure to the lifting cylinders I9 and 20 and for releasing the fluid pressure to permit the hammer to drop.

Suitable force-transmitting means are provided which act upon movement of the hammer to cause equality of movement of both guided ends of the hammer. In the particular construction illustrated such force-transmitting means comprises one or preferably a plurality of taut inextensible flexible members each of which is connected to both ends of the hammer, with means for guiding the respective sections of each flexible member adjacent its attachment to the hammer in opposite vertical directions so that if a preponderance of force is applied to the lighter portion of the hammer, such portion of said force will be transmitted to the heavier portion of the hammer as to cause both ends of the hammer to be lifted at an equal `rate of speed and Aconversely if a preponderance of forceis applied -to the heavier portion of the vhammer 4-the lighter portion of the ham-mer will be caused Ato `move lupwardly Aat the same rate -of speed.

1n itheparticular construction illustra-ted a taut inflexible `Inomics-zr 23 'isrigidly secured at one Vend to za boss 24 upon theextension I=1 of -t-he hammer and has la section *25 extending vertically `upwardly therefrom vover a 1sheave /26 which Vis mounted `upon fthe fbeam i8 and thence 'horizontally over a sheave 21 mounted Iupon the other end .por-tion of the beam E8, thence downwardly against-a guide sheave A28 which is mounted nupon the `upper fend portion of 'the standard 4, thence downwardly aroundasheave 219 which .iis mounted on the lower `portion of the standard `4, thence upwardly -`through :a boss 230 Vto which its end vis adjustabllysecured, fso that :this end portion '3'I of the infiexible member 22'3 1as vwell as the end section 123 `extends vertically. IThe sheaves 7.6 and 219 are .so `positioned as to direct the Aend vsections 25 and 34 respectively Avertically a -distance at least Las great yas the `distance .through `which the hammer drops.

While fa :single ztaut inextensible iiexible member :may be employed, zdesirably `a plurality of such members :are embodied in the machine. As illustrated herein fa complementary taut inextensible .lflexible vmember 32 has Aone lend connected toa :boss 33 fon theiextension I1 olf the hammer. The :end lsection .34 thereof extends vertically downwardly around a sheave35 mounted fon the lower portion ofthe standard '4, thence upwardly along :a guiding sheave :36 mounted `upon the upper portion of 'the standard 4, 'thence over a sheave 3f1 which .is 'mounted vupon .the beam 8, thence horizontally:overa-sheave 38, then vertically downwardly, the end section 39 being adjustably Yconnected tto Ia boss '40 .on the vextension I-6 of 'the hammer.

lBy Yreason of the :Lf-act that each ofthe comp'lementary taut linextensible lexible :members is connected toibothfen'ds of the Lhammer, `with .end sections vextending lvertically .in :opposite directions from their points of =.connec'tion I.to the :hammer, yboth ends .of 'the hammer .move at equal rates of .speed :during the lifting and dropping movements lthereof and tilting of the hammer, which 4would cause vbinding upon the guides, is eliminated.

,Another important .object :of the .invention is to provide `'novel automatically operable means for admitting /fluid under pressure to the cyilnders simultaneously to .raise the hammer, with manually controlled (means for releasing the `iiuid pressure from the 'cylinders to .permit the hammer Vto drop. In the construction illustrated hereinfluid under pressure,.such yas compressed air, lis supplied from `a .suitable source through a cylindrical inlet .conduit 4I having a vsection which desirably extendsrhorizontally through the base of the machine toa valve block 42 which is mounted upon the rear face Vof the base I fas shownin dottedV lines in .Fig.l1 and in Fig. 6. In order Vto-permit .the use of rotatable valves of a ccnvenientdiameter, the valve block 42 is provided uwitha `recess having a circular inlet end complementar-y to and registering with the inlet conduit 4I, and tapering therefrom to arelatively wide somewhat-elliptical outlet 43 as shown in dotted linesinFig. whichcommunicates with a similar routlet `in a A"horizontal valve sleeve 44 which is mountedin the valve-block4l2. A main operating 'three-way `valve 45, which fis rotatably mounted in the sleeve Y'44, is provided with na passage '46 which extendsdiametrically therethrough and also has a port 41 which extends radially from said passage at right-angles thereto, as =il lustrated iin Figs. 7 and `8 of the drawings. The valve S45 is provided at its ends with trunnions which desirably are mounted in anti-friction bearings 4B in the sleeve 44 as Ashown in dotted lines in Fig. '5. The mainoperating valve -45 and its antifriction Vbearings are ,of the s'ame construction as `the Loperating or control valve shown and described Jin our prior Patent No. 1,924,545' and Vparticularly as shown in Figs. 'l0 and 1l of said patent.

An exhaust valve mechanism which is also mountedin lthe valve block 42 in `proximity =to the main operating valve "andas shown iin Figs. 7 and 8 comprises a sleeve 429 having diametrically opposite ports' which communicate respectively through a port 5,0 vvwith a corresponding port in the -sleeve 44 `and with a discharge outlet conduit 5I which may `:be provided with `a flange 52, as shown in Fig. .51to enable *it to be connected Yto a suitable .exhaust pipe. The `exhaust valve 53 iis of cylindrical form .and iis provided with diametrcally opposite 'ports T54 Vand 55 which register respectively with the conduit 5l) andthe outlet5 I. The port 55 vof the .exhaust valve 53 desirably "is of substantially triangular form, .as shown .in Fig. 9, and may be rotarily adjusted to vdetermine .thev effective size .of lthe :exhaust outlet, thereby `vcontrolling the rate at Vwhich the fluid `under `pres-- sure .is vpermitted vto :escape `from the cylinders. The exhaust lvalve .53 desirably iis yprovided with trunnions which are vmounted in anti-friction bearings 56 which in turn are mounted in 4.the sleeve 49, as shown in dotted lines in Fig. 5, and one of `the trunnions .of the exhaust valve 1isprovided with an 4angular vend :portion 151, see Fig. 6 upon whicha'handle .member .58 is Secured, which may be vconveniently moved .manually `to `adjust the area of .the-exhaust outlet.

The valve block 42 is provided with a downwardly extending .passage .5.9 which communicates `with .branches .6U and 6I `which in turn communicate with .conduits =62 iand 63 .leading Vto the 'lower end portions of thecylinders .t9 .and 2.0, as shown in Fig. 5 and in dotted lines 'in Fig. 1.

In `the construction disclosed manually controlled pneumatically operated means are providedor actuating the operating Valve 4.5. The preferred mechanism illustrated :comprisesan integral metal block 64 which tissecured .to Vthe end of the valveblock 42,:as vshown Yin Fig. 5, .and is provided with integral vertical alinedcylinderex`

tensions

65 and 66, the cylinder 65 .having a smaller diameter than that of thecylinderi. A piston 61 in the lcylinder 65 vis connected to Yone end of a.:piston rodigthevother-iend of'saidpiston rod being connected Vto the :piston 69 in the cylinder 66. The piston rod is provided centrally of its 'length with enlarged annular sections between'which .complementary semi-cylindricalsections 10'of an actuatingarm 1I are secured. .As shown'in Fig.16;.the arm .1I .extends between rollers A12 and 13 which extend `inwardly lfrom y a plate 1.41which is xedly mounted upon an angular-extension 15.0f one ofthe trunnionsof'the operating valve 45. A small pipe 16 vleads from the :main inlet conduitlll through a `manually-operable :rotary "three-way valve 11 tothe lower end `ofthe cylinder 66, as vshown in Fig. Landasimilar small pipe "18 -also leads from the main `conduit 4'I to they upper endof thecylinder'65. 'The -valve 1-1 is provided with `a manuallyloperable handle P19.

By reason of this construction the cylinder 65 is supplied constantly with fluid under pressure. When the controlling valve 11 is positioned by the handle 19 to permit the passage of fluid under pressure from the source of fluid under pressure through the pipe 16 to the cylinder 66, the uid pressure upon the piston 69 will force the piston upwardly against the constant pressure upon the piston 61 because of the greater area of the piston 69. It will therefore raise the arm 1I which is secured to the piston rod 68 and thereby rotate the main operating valve 45 to the position illustrated in Fig. 8 in which fluid is allowed to escape from the lifting cylinders I9and 20 through the exhaust valve 53. The three-way controlling valve 11 is provided with a port which when the valve is restored manually to normal position communicates with an outlet 88 in the valve casing through which air under pressure escapes from the section of the pipe leading from the valve 11 to the cylinder 66. When therefore pressure in the section of the pipe 16, leading from the Valve 11 to the cylinder 66, is released, the constant fluid pressure which is supplied to the cylinder 65 will force the piston 61 downwardly, thereby causing the piston rod 68 to rotate the main operating valve 45 to the normal position illustrated in Fig. '1, thereby supplying air under pressure from the inlet conduit 4I through the ports of the

valve

46 and 41 to the cylinders I9 and 20 thereby raising the piston rods 22 thus lifting the hammer and maintaining it in raised position until the control Valve 11 is again actuated manually to release the pressure in the lifting cylinders and permit the hammer to drop.

Assuming that the hammer is resting upon the anvil, the operator in starting the machine will rotate the handle 19 in a direction to cause the valve 11 to exhaust through the port 80 so that air under pressure will be released from the cylinder 66 thereby permitting the pressure on the piston 61 in the cylinder 65 to rotate the main operating valve to the position illustrated in Fig. '1 in which fluid under pressure is supplied to the lifting cylinders I9 and 20. 'I'he pistons of said cylinders will thereupon be raised, thus forcing the piston rods 2| and 22 upwardly and lifting the hammer.

When it is desired to drop the hammer the handle 19 will be rotated in the opposite direction thereby supplying fluid under pressure through the pipe 16 to the upper cylinder 66 so that the piston 69 will be forced upwardly by the pressure in the cylinder 66 and the main operating valve 45 rotated to exhaust position as shown in Fig. 8.

Desirably means are provided for admitting air under pressure to the cylinders I9 and 20 just previously to the impact of the hammer upon the anvil for the purpose of preventing a secondary blow caused by the rebound of the hammer, and

. also for the purpose of applying lifting force to the hammer upon its rebound, thereby saving a considerable amount of energy which otherwise would be required to lift the hammer from the position of rest. This is accomplished in the present construction by providing the controlling valve 11 with a vertical valve stem 8I having secured to it an inclined or preferably spiral cam 82 adapted to be engaged by one of the guideways 83 of the hammer or a suitable pin or lug 82a: projecting therefrom. The cam 82 is adapted to be adjusted vertically upon the valve stem 8|v in such manner as most effectively to cause admission of air under pressure to the lifting cylinders I9 and 20 at the proper moment during rebound of the hammer.

In the operation of the drop hammer therefore the movement of the handle 19 in a proper direction will cause the hammer to drop, and as the hammer descends the cam 82 will be engaged by the pin 82a: on the hammer at the proper time to rotate the controlling valve 11 to exhaust position, thereby releasing fluid pressure from the cylinder 66 through the pipe 16 to cause the rotation of the main operating valve to the position shown in Fig. 7 in which air will be supplied to the lifting cylinders, thus causing the hammer automatically to be raised and maintained in raised position so long as air under pressure is supplied to the cylinders I9 and 2U.

Desirably means are provided for cushioning upward movement of the hammer and to prevent vibration thereof when it is in lifted position. In the preferred construction illustrated fluid operated cushioning means are provided comprising a cylinder 84 extending upwardly from and preferably integral with the central portion of the beam 8 and provided with a head 85. A piston 86, which is reciprocably mounted in the cylinder 84, is provided with a piston rod 81, the lower end of which is adapted to be engaged by an abutment upon the hammer. In the particular construction shown the abutment comprises a head 88 of a screw 89 which extends into an axial bore in the central boss I2 of the hammer. The screw 89 is provided with a nut 90 having suitable Spanner holes 9I by means of which it may be rotated to adjust the position of the head 88 of the screw. The piston rod 81 may be provided with a suitable gland 92 to prevent escape of fluid under pressure from the cylinder along the piston rod 81. Fluid under pressure is led from the main pipe 4I through a branch (not shown) to a pipe 93 having branches 94 and 95 leading respectively to the upper and lower portions of the cylinder 84. The branch 94 of the pipe 93 desirably is provided with a valve 96 which may be adjusted to restrict the rate of passage of the fluid under pressure from the upper section of the cylinder 84.

When in the operation of the machine the hammer is in lowered position the piston 86 and its piston rod 81 will descend by reason of the fact that the air under pressure supplied on opposite sides of the piston 86 through the pipes S4 and 95 will be equal and the weight of the piston and piston rod sufficient to cause it to descend. Upon upward movement of the hammer the head 88 of the screw 89 will engage the lower end of the piston rod 81 and during further upward movement of the hammer the piston 86 will be forced upwardly, thereby forcing air under pressure through the pipe 94 and the restricted passage produced by the valve 96, thereby cushioning the upward movement of the hammer and gradually causing it to come to rest without jarring the superstructure of the frame.

While the particular invention illustrated and described herein comprises two lifting cylinders having pistons acting upon the respective end portions of the hammer, with means operable when the hammer is lifted or permitted to drop to equalize the rate of movement of the ends of the hammer, it is obvious that the equalizing mechanism will operate effectively if only a single cylinder is supplied with fluid under pressure to lift the hammer, or if the lifting force is applied to the hammer by any means at any point or points throughout the length thereof. It is also obvious that similar equalizing means may be applied to the hammer transversely of its 4width to prevent lateral tilting of the hammer effective operation is insured.

Another important object o-f the invention is to provide a novel process of producing an anvil die and a complementary hammer die in such manner as to provide uniformity of the complementary co-acting die surfaces and to insure accuracy of registration of all portions of the hammer die with those of the complementary anvil die.

The anvil die may be constructed as heretofore described by casting the zinc or bronze composition in a matrix of plaster of Paris and then removing the matrix and turning over the die and securing it upon the anvil.

Figs. and 11 of the drawings illustrate a drop hammer having an anvil provided with an anvil die and a hammer similar to that heretofore described with the exception of the omission of `the transverse reenforcing web I5 and showing the manner in which the hammer die is cast directly upon the hammer.

In order to prevent displacement of the anvil `die upon the anvil the upper surface of the .anvil desirably is provided with a series of grooves 91 extending both longitudinally and transversely over a somewhat larger area than the under surface of the anvil die.

A vertical frame 9B of suitable material is then placed upon the anvil closely surrounding the periphery of the anvil die and desirably has extensions which project into the grooves 91 of the anvil die to hold the frame in place. The frame 9B extends above the upper surface of the anvil die the necessary distance to provide for the proper depth of the hammer die. The body of the hammer 9 is provided with a sufficient number of properly distributed holes to receive anchoring bolts 99 the heads of which extend a considerable distance below the under face of the hammer head. The hammer is also provided with inverted conical sprue holes |00 through which the lead, or other relatively soft metal may be poured .into the frame which surrounds the anvil die. Y

In forming thehammer die the hammer is lowered gently until it rests upon the upper edge of the frame 98, with the bolts .99 depending into rthe space between the hammer and the upper surface of the anvil die. The molten lead, or other relatively soft metal, is poured through the conical sprue holes |110 until the entire chamber within the frame is filled and until the metal overiiows through the sprue holes. Any number of -such sprue holes may be employed and the metal poured through them simultaneously or as rapidly as possible to -produce an integral anvil the hammer and after the chamber of the frame has been filled with molten metal the hammer is lowered untilthe metal is forced into the dovetail recesses and the hammer permitted to remain in such position until the metal is cool. 'Ihis method is objectionable forthe reason that the pressure of the hammer frequently causes the excess of molten metal in the frame to be squirted out thus endangering the operator. Furthermore, the lowering of the cold hammer upon the molten metal chills the upper surface thereof. This method is further objectionable in that it is very difficult to remove the soit metal die from the plate to which it is secured by the insertion of wedges in the grooves which are likely also to distort the die and unfit it for further use.

By the present method the heat of the metal transmitted to the hammer during the pouring operation suiiiciently heats the metal of the hammer to reduce the chilling effect upon the molten metal to a minimum. Furthermore, the conical sprue holes provide risers which enable all of the air to escape from the chamber of the frame, thereby insuring complete lling of the frame and homogeneity of the metal of the hammer die.

Inasmuch as the hammer is stationary during the pouring operation, all danger of squirting of the metal by the previous process above described is avoided.

By reason of the present invention the hammer die can be readily removed from the hammer by merely removing the nuts of the bolts and raising the hammer and when it is desired to replace the die the bolts will register with the holes and any slight deviation will be compensated by the engagement of the metal forming the conical protuberances IUI with the complementary walls of the sprue holes IBI! through which the metal has been poured,

By reason of the present method therefore the hammer die can be more safely made and when constructed in this manner is of a more homogeneous character than those produced by previous methods. It is also easily adaptedV for removal and replacementwithout distortion, and accuracy of operation thereby insured.

When the hammer die has been formed in the above manner, the hammer is raised, the frame 98 removed, and the hammer then permitted to drop upon the anvil die. Such dropping of the hammer will force the anvil die downwardly so that the metal of the under face of the anvil die will be driven into the recesses 91 in the anvil, thereby xedly positioning the anvil in place and insuring perfect registry with the hammer die during the die-shaping of the blanks of metal which are placed upon the anvil die.

It will be understood that the particular embodiment of the invention shown and described herein is of an illustrative character and is not vrestrictive -of the meaning 'and scope of the following claims.Y

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

l. A drop hammer construction comprising a base having an anvil, a frame mounted on said base having widely spaced vertical guides for the ends of the hammer, an unsymmetrically weighted hammer reciprocably mounted in said guides, vertical pneumatic cylinders mounted respectively on the end portions of said base having pistons provided with upwardly extending piston rods engagingthe respective end portions of the hammer, means for supplying air under pressure to said cylinders to cause the pistons thereof to push the hammer upwardly, manually operable means for simultaneously releasing the air under pressure from said cylinders to permit the hammer to drop, and means for transmitting force from one end of the hammer to the other to equalize the rate of movement of the guided end portions of the hammer throughout the lifting and dropping movement thereof,

2. A drop hammer construction com-prising a base having an anvil, a frame mounted on said base having widely spaced vertical guides for the ends of the hammer, an unsymmetrically weighted hammer reciprocably mounted in said guides, vertical pneumatic cylinders mounted respectively on the end portions of said base having pistons provided with upwardly extending piston rods engaging the respective end portions of the hammer, means for supplying air under pressure simultaneously to said cylinders to cause the pistons thereof to push the hammer upwardly, manually operable means for simultaneously releasing the air under pressure from said cylinders to permit the hammer to drop, complementary inextensible flexible power transmitting means each connected to both ends of sai-d hammer, and means for guiding the same to cause said inextensible members to act upon the end portions of the hammer in opposite directions during the lifting and dropping movement thereof thereby to equalize the rates of movement of the ends of the hammer and to prevent binding action between the respective ends of the hammer' and the guides.

3. A drop hammer construction for shaping large unsymmetrical articles comprising a base provided with an anvil having an unsymmetrical die mounted thereon, a frame having vertical standards extending upwardly from said base and provided with guides for the hammer, a cross beam connecting the upper ends of said standards, a hammer reciprocably mounted in said guides, carrying an unsymmetrically weighted die complementary to said anvil die, vertical pneumatic cylinders mounted on the end portions of said base having pistons provided with upwardly extending piston rods connected respectively to the end portions of the hammer, means for simultaneously supplying air under pressure to said cylinders to raise said hammer, means for releasing said air under pressure from said cylinders to permit the hammer to drop, upper sheaves mounted on said frame above the respective ends of said hammer, a lower sheave mounted upon the lower portion of one of said standards, and a taut inextensible flexible member connected at one end to the end portion of said hammer and extending vertically upwardly therefrom over an upper sheave, thence horizontally over the other upper sheave, thence downwardly around the lower sheave, and thence vertically upwardly and connected 'at its end to said hammer, and operable during the movement of the hammer to equalize the rates of movement of the ends of said hammer.

4. A drop hammer construction for shaping large unsymmetrical articles comprising a base provided with an anvil having an unsymmetrical dieY mounted thereon, a frame having vertical standards extending upwardly from said base and providedwith guides for the hammer, a cross beam connecting the upper ends of said standardsy a hammer reciprocably mounted in said guides, carrying an unsymmetrically weighted Ydie complementary to said anvil die, vertical pneumatic cylinders mounted on the end portions of said base having pistons provided with upwardly extending piston rods connected respectively to the end portions of the hammer, means for simultaneously supplying air under pressure to said cylinders to raise said hammer. means for releasing said air under pressure from said cylinders to permit the hammer to drop, upper sheaves mounted on said frame above the respective ends of said hammer, a lower sheave mounted upon the lower portion of one of said standards, and a taut inextensible flexible member connected at one end to the end portion of said hammer and extending vertically upwardly therefrom over an upper sheave, thence horizontally over the other upper sheave, thence downwardly around the lower sheave, and thence vertically upwardly and connected at its end to said hammer, and a complementary taut inextensible ilexible member reversely connected in like manner to the ends of said hammer and passing over similar upper sheaves and a lower sheave mounted upon the opposite standard.

5. A drop hammer construction comprising a frame having vertical guides for the hammer, a hammer reciprocably mounted in said guides, means for lifting said hammer including a cylinder and piston, an inlet conduit leading from a supply of air under pressure to said lifting cylinder, an operating valve in said conduit having ports respectively to establish communication between said supply and said cylinder and to exhaust the fluid pressure from said cylinder, means for positioning said operating valve comprising oppositely disposed cylinders of different diameter provided respectively with pistons having a common piston rod having means for actuating said valve, means for simultaneously supplying air under the same pressure from said supply of air under pressure to both of said cylinders operable by the greater effective pressure on the larger piston so to position said operating valve as to supply fluid under pressure to said lifting cylinder, and manually operable means for releasing the fluid under pressure from the larger cylinder only to cause the uid pressure in the smaller cylinder to move the operating valve to exhaust position.

6. In a drop hammer construction comprising a base provided with an anvil, a frame having vertical standards extending upwardly from said base and provided with guideways for a hammer, a hammer reciprocably mounted in said guideways, pneumatically operable means mounted on end portions of said base having means for simultaneously raising both ends of said hammer, means for supplying air under pressure to said pneumatically operable means, and means for releasing the fluid pressure from said pneumatically operable means to permit the hammer to drop, means for cushioning and arresting the upward movement of said hammer comprising a cylinder mounted on said frame having a piston reciprocable therein provided with a piston rod extending into the path of said hammer, means for supplying fluid under pressure to said cylinder comprising branch pipes communicating with said means for supplying air under pressure and having branches communicating respectively with the upper and lower chambers of said cylinders above and below its piston, and adjustable means in the branch leading to the upper chamber for restricting the passage of air under pressure therethrough operab'le when the piston is forced upwardly by engagement of the hammer with said piston gradually to arrest the upward movement of said hammer by restrictingthe ow of fluid through the branch conduit leading to the upper chamber of the cylinder and upon equalization of the pressure in said upper and lower chambers of the cylinder to permit said piston and piston rod to descend to normal position by virtue of the weight of said piston and piston rod.

7. A drop hammer construction comprising a base provided with an anvil, a frame having vertical standards extending upwardly from said base and provided with a guideway for the hammer, a cross beam connecting the upper ends of said standards, a hammer reciprocably mounted in said guides, vertical cylinders mounted on the ends of 'said base each having a piston provided with a vertical piston rod oonnected to an end portion of the hammer, means for supplying uid under pressure simultaneously to said cylinders to raise the hammer, means for simultaneously releasing the fluid pressure in said cylinders, and means for cushioning and arresting the upward movement of said hammer comprising a cylinder Amounted upon said beam midway of its width having a piston reciprocable therein provided with a piston rod extending into the path of the hammer, means for supplying fluid under pressure to said cylinder comprising a pipe leading from said fluid pressure supply and having branch pipes communicating respectively with the upper and lower ends of said cylinder, and adjustable means for restricting the passage of said fluid under pressure through the pipe which communicates with the upper end of said cylinder.

8. A drop hammer construction as in claim '7, characterized in that the hammer is provided with an upwardly extending boss, a screw mounted in said boss having a head forming an abutment to engage the lower end of the piston rod of the piston of the cushioning means and a nut for said screw mounted upon the upper end of said boss.

WILLIAM H. J. FITZGERALD. REGINALD P. FITZGERALD.