US1958214A

US1958214A - Means for forming the banjo and frame of a rear axle housing

Info

Publication number: US1958214A
Application number: US426545A
Authority: US
Inventors: Spatta George
Original assignee: Clark Equipment Co
Current assignee: Doosan Bobcat North America Inc
Priority date: 1930-02-07
Filing date: 1930-02-07
Publication date: 1934-05-08
Anticipated expiration: 1951-05-08

Description

G. SPATTA May 8, 1934..

MEANS FOR FORMING THE BANJO AND FRAME OF A REAR AXLE HOUSING 5 Shets-Sheet l Filed Feb. 7. 1930 May 8, 1934. G SPATTA 1,958,214

MEANS FOR FORMING THE BANJO-AND FRAME OF A REAR AXLE HOUSING Filed Feb. 7. 1930 5 Sheets-Sheet 2 May 8, 1934. G. sPATTA 1,958,214

MEANS FOR FORMING THE BANJO AND FRAME OF A REAR AXLE HOUSING Filed Feb. 7. 1930 5 Sheets-Sheet 3 .w 5 QE@ 7 e mwmw m m m n www W mN// @S+ www@ Q@ Nm Ym NQN wMNImQN- QN TSN @N \WQ\% G. SPATTA May 8, 1934.

MEANS FOR FOHMING THE BANJO AND FRAME OF A HEAR AXLE HOUSING 5 Sheets-Sheet 4 Filed Feb. 7, 1930 Nm Mm.

@ l wwf G. sPATTA May 8, 1934.

MEANS FOR FORMING THE BANJO AND FRAME OF A REAR AXLE HOUSING l 5 Sheets-Sheet 5 Filed Feb. '7, 1930 Patented May 8, 1934 UNITED STATES PATENT OFFICE George Spatta, Buchanan, Mich., assignor to Clark Equipment Company, Buchanan, Mich., a corporation of Michigan Application February 7,

Claims.

This invention relates to the means for forming the banjo and frame of a rear axle housing.

In my copending application, Serial No. 416,537, led December 26, 1929, now issued as Patent No.

1,926,353, I disclosed a method of forming rear axle housing for vehicles, that method including a number of steps progressively performed upon a tubular blank to fabricate it into the nished article. The present invention primarily relates to one of the steps in this process, and I have illustrated my invention by showing a machine designed to perform a specific operation in that method, although I am aware that the invention is applicable to other similar processes.

Briefly, the steps in the process disclosed in my above mentioned copending application consist of slotting the tubular blank, shrinking the end sections of that blank to a smaller diameter, changing the shape of the walls freed by the slots in the blanks from their original shape, which is that of part of a cylinder with a horizontal axis, into a different shape, namely, to parts of a cylinder with a vertical axis or vertical axes, and then spreading and shaping the walls of this latter cylinder to form the banjo of the housing. The present invention relates specifically to the spreading and forming operation and to the machine and dies for performing this operation.

The preliminary changing the shape of the walls of the blank in the region of the slots is disclosed in full in my copending application, Serial No. 425,426 filed February 3, 1930, now issued as Patent No. 1,925,850, that operation being performed solely for the purpose of expanding the slot area sufficiently to permit inserting the punches that are employed to form the banjo of the housing in accordance with the teachings of the present invention. In this preliminary operation, the arcuate wall sections between the C oppositely disposed slots in the blank are changed into wall sections of a transverse cylinder, with a consequent stretching of the metal at the edge oi' the wall sections at the mid-section of the blank that is at the points of application of the dies to the blank. This preliminary spreading of the walls is accomplished without affecting the metal at the critical section of the blank, since the dies do not reach that metal and since their operation is merely one of reshaping the arcuate Walls which they engage. As is pointed out in my above mentioned Patent No. 1,926,353 the critical section of the blank lies at the ends of the slots.

Banjo housings of the type that the machine disclosed in the instant application is designed to manufacture have a centrally located cylindrical 1930, Serial No. 426,545

portion whose axis is disposed transversely of the axis of the housing. This central cylindrical portion is provided with flanges which project radially inward from its opposite edges, those flanges serving as plates to which the covers and drive shaft casing of the vehicle are attached.

The depth of the web section between these flanges is materially less than the diameter of the blank from which the housing is made, and the banjo forming operation therefore must fold the edges of the mid-section of the blank over and inwardly to form the llanges and must spread the web sections outward and form them into arcuate shapes so that they will lie on the circumference of the cylindrical banjo of the completed housing.

In the performance of this operation, in accordance with the teachings of the present invention, the folding of the metal at the edges of the wall sections between the slots causes a gathering of metal in the flange of the banjo, this gathering compensating for the stretching that has occurred in these sections during the step of preliminarily spreading these wall sections. The operation of spreading the webs of the banjo stretches the metal in those webs at points adjacent to the junction of the tubular end sections of the housing with the slotted central portions of it, that is, at the critical sections of the blank.

From the foregoing it will be seen that the problem resolves itself into changing a portion of a cylindrical blank into a flanged cylinder of larger diameter and having its axis disposed at right angles to the axis of the original blank. This change must be made in several steps and each step must be carried out with the succeeding step in mind so that the metal of the blank will not be worked unduly. In the fabrication of a particular axle housing, the perimeter of the slots punched in the blank is approximately equal to the perimeter of the inner edge of the flange of the finished housing. The perimeter of these slots is increased by the stretching of the metal during the operation of forming the walls between the slots into sections of a cylinder having its axis disposed transversely of the axis of the blank. This stretching is made to occur at the midsection of the slots, that is, on the transverse median line of the blank, so that the ends of the slots are not torn and the blank thereby ruined. The operation of folding over the flanges on the cylindrical wall sections thus formed is started slightly in advance of the stretching of the web section of the banjo, and the natural tendency of the metal in the flange to be thickened by such a bending along an arc is utilized to compensate for the prior stretching of the metal. This folding over operation and the consequentl gathering of metal in the anges produces flanges having perimeters approximately the same as the perimeters of the original slots.

By proper design of the dies made with the wall thickness of the blanksy taken into consideration, I am able to regulate the gathering of metal in the flange to suoli an amount that the thickness of the flange in thefinished article is the same as the thickness of the web sections, and the housing is therefore made to have the maximum strength with a minimum amount and weight of material. This equalizing of the thickness of the various parts of the banjo housing is thus accomplished by utilizing the natural tendency of the metal to flow upon being bent under the condition under which it is bent, and without definitely upsetting the metal in the flange.

The spreading and shaping of the web of the banjo, which causes stretching of the metal at the critical sections of the blank, also reduces the overall length of the blank, in one instance this reduction amounting to two inches. This reduction of length of the blank is occasioned mainly by drawing the critical sections nearer together. The end cylinders of the blank are clamped during this operation but not so tightly as to prevent a limited longitudinal movement of the cylinders. Some metal is drawn from 'the critical sections and end cylinders immediately adjacent thereto to provide metal for the web section of the banjo, which section is of substantially longer diameter than the diameter of the tubular blank from which the housing is made.

The machine employed to carry out this step of the process preferably comprises a hydraulic forging press consisting 0f a vertically disposed cylinder and ram and a horizontally disposed cylinder and ram. The die structure consists of a stationary die block and a movable die block, each of these blocks being provided with clamping members which engage the tubular end sections of the blank and hold those sections in alignment during the performance of the operation.

A pair of forming punches are mounted in the press between the stationary and movable die blocks, and the blank that is to be forged in the machine is placed over these punches when they are in their normal or collapsed position.

The horizontal ram is connected to the movable die, andis operated by its cylinder to move that die horizontally to bring it into engagement with the stationary die, the movement being limited by adjustment of the clamping member. The punches are also moved by this operation, and the work and punches are thereby brought into alignment with the vertically disposed ram. This horizontal movement of the movable die, the punches, and the work serves also to preliminarily bend the edges of the central section of the blank as will hereinafter appear. The vertical ram is then operated to engage the punches and expand them to thereby force the wall sections of the work into the dies to form those sections into the prescribed shape. The vertical ram is then withdrawn, this withdrawal closing the punches and contracting them away from the nshed work, and the horizontal ram is then operated to withdraw the clamping engagement from the work to thereby permit its removal from the machine.

In the preferred embodiment of my invention, the rams of the machines are hydraulically operated, although I am aware other suitable modes of operation can be substituted within the teachings of my invention.

Now, to acquaint thoseskilled in the art with the teachings of my invention, reference is made to the accompanying drawings in which the preferred embodiment of it is shown by way of example, and in which:-`

Figure 1 is an elevational view of the forging press taken from the front or open side of it;

Figure 2 is an elevational side view of the press;

Figure 3 is a plan view of the punches and dies taken along the line 3-3 of Figure 1, looking in the direction of the arrows;

Figure 4 is a bottom side plan view of the wedge employed to operate the punches;

Figure 5 is a cross-sectional view taken along the line 5 5 of Figure 3 and showing the punch and die structure in its normal or open position;

Figure 6 is a view similar to Figure 5 showing the punch and die structure in its operated or closed position;

Figure 7 is a cross-sectional view of Figure 6 taken along the line '1 -'7 looking in the direction of the arrows;

Figure 8 is a cross-sectional plan view of the punch and die structure taken along the line 8-8 of Figure 6, looking in the direction of the arrows;

Figure 9 is a cross-sectional view of the die taken along the line 9-9 of Figure 8, looking in the direction of the arrows;

Figure 10 is a view taken along the line 10-10 of Figure 8 showing the details of the connection of the ram to the movable die;

Figure l1 is a fragmentary cross-sectional view taken along the line 11-11 of Figure 6 showing the shape assumed by the sections of the blank adjacent the die at the completion of this step in the process;

Figure 12 is a cross-sectional view of the clamping members taken along the line 12-12 of Figure 8;

Figure 13 is a cross-sectional view of the operating wedge taken along the line 13-13 of Figure 5 and showing the dovetail flange on that wedge;

Figure 14 is a perspective view of the blank at the completion of this step in the process; and

Figure 15 is a cross-sectional View taken along the line 15-15 of Figure 5 looking in the direction of the arrows and showing the details of the punches. 1

Referring to Figures 1 and 2 of the drawings now in more detail, the forging press comprises a frame 1 which is of generally C-shape, and which has a flat table portion 2 adjacent its lower open end. The punch and die structure, indicated generally at 3, is mounted on this fiat table portion. A pressure flange 4 is formed integral with the frame and rises vertically above the upper surface of the table portion at the extreme outward end of that portion cf the frame, this pressure flange serving as a stationary mount for the die structure and to resist the pressure placed on that die structure longitudinally of it.

A horizontal cylinder 5 is disposed adjacent the flat table 2, and provided with a ram 6 which is adapted to operate over the upper surface of that table to control the operation of the die structure 3. Preferably, the cylinder 5 is provided with a cylinder head 'l which is held against the cylinder 5 by external bolts 8 which are threaded into the frame work 1 and provided with nuts 9 which bear against the outer surface of the cylinder head 7 to hold it on the cylinder 5.

This puts the walls of the cylinder 5 normally under compression, as is well understood by those skilled in the art, and they are therefore better able to withstand the pressures built up within them in the operation of the machine.

A second cylinder 11 is disposed at the extreme end of the upper part of the frame work 1 with its axis perpendicular to the table surface 2, this cylinder 11 being provided with a ram 12 which is operated in a vertical direction to engage the punch and die structure to operate that structure in a manner which will. be hereinafter more fully explained. Preferably, the cylinder 11 is also provided with a cylinder head 13 which is held thereon by external bolts 14 and nuts 15 to place the walls of the cylinder 11 normally under compression so that they may better resist the pressures built up within them in the operation of the machine.

A. control valve 16 is mounted on the frame work l of the machine in any convenient manner and arranged to be operated by the lever 17 to control the operation of

rams

6 and 12. In the preferred embodiment of .the machine shown in Figures 1 and 2, the cylinders 11 and 5 are hydraulically operated, although other suitable means for operating the rams of these cylinders may be substituted within the teachings of my invention.

The ram 12 is provided with a cross head 18 upon which the operating wedge is mounted, this cross head being provided'with a projecting arm terminating in the boss 19 in which a guide rod 20 is fitted and held by a screw 21. The frame work 1 is provided with a collar 22 through which the guide rod 20 passes, the rod thereby preventing rotation of the ram l2 with respect to the frame work 1 during the operation of the ram, for purposes which will be more fully brought out hereinafter.

Preferably, the frame work 1 is a metallic casting, and as such is provided with the usual rein-- forcing ribs and flanges the details of which form no part of the instant application and are not therefore explained in detail herein.

From Figures 1, 2, 3, 5, 6 and 7, it will be apparent that the die structure, indicated generally at 3, is supported on a bed plate 30, which bed plate is in turn bolted to the table top 2 of the machine frame work. Preferably, the bed plate 30 comprises an upper flat surface 31 upon which the die structure is tted and adapted to slide, this surface being provided with upwardly extending anged edges 32 which serve as guides to prevent movement of the die transversely of the axis of the ram 6. The bed plate 30 is also provided with outwardly extending flanges 33 through which the bolts 34 are projected and threaded into the table top 2 to hold the bed plate thereon.

The' die structure comprises a stationary member 40 which consists of a forming die 41 located centrally of the member 40 and in alignment with the axis of the ram 6. Clamping

members

42 and 43 are disposed on opposite sides of the forming member 4l, the clamping members serving to grip the ends of the blank and to hold them in alignment during the performance of the forging operation by the machine.

The stationary die is held in the machine by the bolts 44 which are extended into the bed plate 30, and is held against movement longitudinally of the axis-'of the ram 6 by a spacing block 45 interposed between the back side surface of the die member 40 and the pressure flange 4 of the frame work.

The forming die 41 comprises a central forming member 46 which has a forming surface 46' machined to the contour to which the web section of the banjo is to be formed. Batter plates 47 and 48 a're disposed upon opposite sides of the forming block 46, these plates preferably being constructed of hardened steel so that they may better resist the friction imposed upon them by the blank as it is being forced into the die.

The batter plates 47 and 48 project over the working surface 46 of the forming block 46, to form a flange, the outer surface 50 of which is formed as an arc whose center coincides with the center of the arc 46 of the forming block 46.

The plates 47 and 48 are held on the forming block 46 by the bolts 44 which also hold the assembly on the bed plate 30.

The movable die member is similarly constructed and comprises a forming block 61 which has an arcuate forming surface 62 and is provided with batter plates 63 rand 64 which, like the batter plates 47 and 48, are preferably made of hardened steel so that they will better resist wear. The

plates

63 and 64 project from the arcuate working surface 62 of the forming block 6l and terminate in an arcuate edge 65 which is formed on a radius the center of whichcoincides with the center of the forming block 62. Bolts 68 hold these

members

61, 63 and 64 together and, since the assembly must be movable with respect to bed plate 30, the bolts are threaded into the plate 64 and do not touch the plate 30.

Clamping

members

66 and 67 are disposed on opposite sides of the movable forming die 60, those members cooperating with the

members

43 and 42, respectively, to grip the cylindrical end sections of the blank to hold them in alignment during the operation of the machine.

As will best be seen in Figure 12, the clamping member 67 terminates in two flange-

like projections

52 and 53, and the clamping member 42 terminates in a tongue-like member 54 which lits inside of the members 52 and 53.` The web section of the flange of the member 42 is formed arcuately to conform to the exterior surface of the blank 55, and the end of the tongue section 54 of the member 67 is similarly formed to this same section.

When the movable clamping member 67 is extended to its completely operated position, in which it is shown in Figure 12, the surfaces 56 adjacent the projecting tongue 54 strike against the extreme end of the

flanges

52 and 53, serving to limit the movement of the member 67. At this time, the extreme ends of the projecting tongue 54 fall a little short of meeting the web section of the member 42, so that the blank 55 is not tightly gripped by the clamping members. 'I'he movable die 60 is carried on the end of the ram 6 and, as will be seen in Figures 5, 6, 8 and l0, the connec tion between the ram and the die member is adjustable. The end of the ram is threaded as shown at 70, and a threaded coupling member 71 is screwed into the threaded opening 70 in the ram and locked therein by a lock nut 72. The end of this coupling member 71 adjacent the die member 60 is provided with an annular groove 73 interposed between the main portion 74 of the member and the head portion 75. Two

plates

76 and 77 are provided each with a semi-circular indentation the radius of which corresponds to the radius of the bottom section of the groove 73, these plates being attached to the end of the die 60 by screws or bolts 78 which rigidly hold them on the die and establish a connection between the coupling member 71 and the die structure 60. A batter plate 79, made of hardened steel, is interposed between the plates 76 and 7 7 and the end of the block 61 and held in place by bolts 78. The head 75 of the rod 74 bears against this plate.

By suitable adjustment of the coupling member 71, the ram 6 and the die 60 can be brought into proper relation with respect to each other to permit the surfaces 56 of the die to rest against the

flanges

52 and 53 of the stationary die when the ram 6 is in its fully operated position.

'I'he engagement of the

iianges

52 and 53 with the surfaces 56 also serves to position the movable die member 61 accurately with respect to the stationary die member 46. Since the

batter plates

47, 48, 63 and 64 are fixed with respect to these dies, their working edges 50 and 65, respectively, are thus accurately located, for a purpose which will appear more fully hereinafter.

The punches 80, which cooperate with the dies 40 and 60 to form the blank into the desired shape, consist of L-shaped supports 81 and 82 which are laid on the bed plate 30 with their longer legs against that plate. As will be seen in Figure 9, the bed plate 30 is provided with a longitudinal slot 83 which is of rectangular cross section and into which the long leg of the support 81 is fitted and guided. Similarly, the long leg of the support 82 is fitted in the slot 83 and guided thereby.

The shorter and up-turned legs of the supports 81 and4 82 are abutted against each other and disposed with their outward faces substantially normal to the face of the bed plate 30. These supports 84 and 85 serve as a mounting means upon which the forming

blocks

86 and 87 are mounted in any convenient manner, such as by the screws 88. These forming

blocks

86 and 87 when fitted together form an oval shaped punch of such dimension as will fit within the broad side walls of the blank after that blank has been preliminarily separated in the manner pointed out in my copending application now issued as Patent No. 1,925,850.

The upper surface of the punch 86 is cut away on a taper 89 and a wedge block 90 fitted thereon and loosely held in place by the screws 91, this wedge block 90 being forced upward by the bevel surface 89 as the punch is made to enter the die, thereby to increase the height of the punch to its maximum value which is sufficient to properly form the blank into the desired shape.

When the punch is being withdrawn from the die, in the manner which will hereinafter be brought out, the wedge block 90 slides downward on the bevel surface 89 to contract the vertical height of the punch to thereby permit withdrawing the punch from the finished work. The heads of the screws 91 limit this downward movement of the block and, since those bolts are projected through clearance holes in the block 90, the wedge block is capable of an upward movement as well as an outward movement with respect to the block 86.

Similarly, the forming block 87 is provided with a tapered surface 92 upon which the wedge block 93 is positioned and held by the bolts 94, those bolts likewise being projected through clearance holes which permit lateral and vertical movement of the wedge block 93 with respect to the forming block 87.

The abutting surfaces of the4 vertically disposed

legs

84 and 85 of the supports 81 and 82 are cut away to form a tapered slot 95 the edges of which are provided with dovetails 96. The wedge 100, carried by the ram 12, is machined to fit within the beveled slot 95 and contains dovetails 101 which register with the dovetails 96 ofthe support members in such a manner that the supports are separated by a downward movement of the wedge 100 and contracted through the action of the dovetails by an upward movement of the wedge.

Preferably, the wedge consists of a central block 102 on the opposite sides of which the hardened plates 103 are placed and held by through bolts 104, so that the friction encountered in the operation of the wedge against the supports 81 and 82 is taken up by the hardened plates 103, which can be renewed or resurfaced as the occasion demands. The bed plate 30 is provided with an opening 105 and the frame 1 is provided with an opening 106 registering therewith and into which the point of the wedge 100 can project when it is in its lowermost position and the punches are spread into the dies 40 and 60.

The block 45, against which the stationary guide 40 is abutted, is located immediately above the upper surface of the foot of the support 82, to resist any tendency of that foot to rise up off of the bed plate 30 when the wedge is moving downward. The pressure flanges 4on the frame work are separated to leave a groove 107 between them into which the end of the foot 82 can project, and a plate 108 is provided on the outward end of the fianges 4 and held thereon by the bolts 109 which project through the feet and into the plate 45, to guard against the possibilty of injury to the end of the foot 82 while it is projecting into the slot 107.

In the operation of the machine, the blank is placed over the

punches

86 and 87, in the manner shown in Figure 5, and is brought to bear upon the upper surfaces of the positioning blocks 110 and 111, which blocks areV fastened onto the supports 8l and 82, respectively, by screws 112. Preferably, the blocks 110 and 111 are hardened metal, such as steel, so that the wear of the block will be minimized and the blanks will therefore be properly located in the machine.

When the punches are expanded, into the position in which they are shown in Figure 6, the blocks 110 and 111 slide into grooves 113 and 114 in the

batter plates

64 and 48, respectively, these grooves being suiiiciently large to permit free entrance and departure of the plates from them without friction.

The operation of the machine is as follows:-

The slotted tubular blank is first heated to forging temperature, preliminarily spread in the manner pointed out Ain my copending application, Patent No. 1,925,850, previously referred to, and transferred from that machine to the machine shown in the drawings of the instant application. The blank is slipped over the forming

punches

86 and 87, the parallel walls 120 and 121 of the blank coming to rest upon the upper surface ofthe positioning blocks 110 and 111. It will be remembered that in the straightening of these walls 120 and 121 in the previous step of the process, the upper and lower edges of the walls were stretched at their mid-section and as a consequence are somewhat thinner than the mid-section of the walls.

The lever 17 is operated to cause pressure from a pressure source, not shown, to be admitted vthe parallel walls 120 and 121.

to the cylinder 5 to force the ram 6 to the right, Figures 5, 6 and 8, thereby moving the movable die 60 to the right. The projecting tongue 54 of the clamping member of this die engages the end section 122 of the blank, and the corresponding tongue on the clamping member 67 engages the end section 123 of the blank. Simultaneously, the arcuate face of the forming

flanges

63 and 64 of the movable die engage the upper and lower edges of the wall 120 of the blank. As the ram 6 continues to move forward, the

punches

86 and 87 and their supporting members 81 and 82, the blank, and the movable die 60 are moved to the right by the movement of the ram. When the forward edge of the tongue 54 engages the anges 52 and 53 of the stationary die, the forming edge 50 of the flanges 47 and48 of that die engagesthe upper and lower edges of the wall 121 of the blank, and the clamping surface 55 of the

stationary clamping members

43 and 42 engage the

end sections

122 and 123 of the blank. The distance between the forming edges 50 and 65 of the batter plate is less than the width of the blank, that is, less than the distance between l Therefore, as the ram moves the movable die into its operated position, the edges of the walls 120 and 121 are bent inwardly by being engaged by the forming edges 50 and 65 prior to the completion of the operation of the ram. During the final movement of the dies on closing, the end cylinders of the work are gripped rmly by the clamping surfaces 55 so as to hold those portions of the blank securely in alignment and against unwanted movement in all directions. 'I'he machine has then completed the first step of its operation, and the ram 6 is brought to rest.

In the preferred embodiment of the invention, the pressure that has been operating the ram 6 is now automatically shunted into the cylinder 11 to operate the ram 12 to push it downward and thereby bring the wedge 100 into engagement with the wedge-shape notch 95 in the

punches

86 and 87. As the ram 12 continues in its downward movement, the punches are separated, and the Walls 120 and 121 of the blank are now completely folded into the dies 60 and 40, respectively.

During the rst part of the travel of the punches from the position in which they are shown in Figure 5 to the position in which they are shown in Figure 6, the upper and lower edges of the Walls 120 and 121 are folded over onto the upper and lower surfaces, respectively, of the punch members, this folding gathering metal in the flange at the

points

125 and 126, those being the points which were stretched during the preliminary spreading of the

walls

121 and 122 in the machine disclosed in my Patent No. 1,925,850.

As the

punches

86 and 87 continue moving into the die, the

web sections

127 and 128 of the

Walls

121 and 122, respectively, are stretched to increase their length and to fit them into the inside surface of the dies, as shown in Figures 6 and 7. The stretch of metal during this step of the process occurs at

points

128, 129 and 130 which are at the junction of the

cylindrical end sections

122 and 123 and the transverse central cylindrical section of the blank. The clamping members and die forming blocks engage the sides of the blank at this point, but leave the upper and lower surfaces of the blank free so that the movement of the metal is confined to those surfaces engaged by the die members.

Referring to Figure 14, metal is gathered in the flange of the blank at

points

125,and 126, and stretching occurs at the points 129 and 130, this stretching being confined to the

opposite sides

131 and 132 of the region 129 and to the points 133 and 134 of the region 130. The operation of the punches and dies to spread the

webs

127 and 128 apart draws the

end cylinders

122 and 123 together by moving them longitudinally in the clamps by which they are engaged. The overall length of the blank is thereby reduced.

Prior to the forming of the banjo in the blank, the regions through the ends of the

end sections

122 and 123 were frusta-conical in shape, and after the metal has been stretched and flattened at points 13o-134, inclusive, these sections assume a somewhat oval shape from the upper and lower faces of which project the regions of

undisturbed metal

135 and 136. The forming of this particular region is carried out in the so-called throating operation which is described in my co-pending application, now issued as Patent No( By proper design of the dies, and choice of wall thickness and size of the blank, the stretching of metal at the points 130-134 is reduced to a minimum so that the wall thickness and strength of the metal in the critical section of the blank is not greatly impaired.

After the ram 12 has moved to its lowermost position and the wedge 100 operated to fully expand the punches into the dies, pressure in the cylinder 11 is reversed so that the ram 12 is raised.

During the downward operation of the wedge 100, the wedge blocks and 93 on the punches were forced up over the

inclined surfaces

89 and 92, respectively, to expand the vertical height of the forming dies 86 and 87 to its maximum, which maximum ts the punch in the dies with sumcient clearance between the two to permit the flanged edge of the walls 120 and 121 of the blank to fit therebetween.

When the ram 12 starts in an upward direction, the dovetail connection between the members 101 of the wedge and 96 of the punches retracts the punches from the die, the flrstmovement of retraction sliding the wedge blocks 90 and 93 downward on their

inclined surfaces

89 and 92, respectively, causing them to shrink the outside dimension of the punch so that it may be withdrawn from the flanged walls of the blank without injury to those walls.

'I'he wedge 100 continues to rise as the ram 12 is moved upward, clearing itself from the punches when those punches are completely closed. When the ram 12 has reached its uppermost position in which it is shown in Figures 2 and 5, the pressure in cylinder 5 is released and the ram 8 retracted into that cylinder to thereby withdraw the movable die member 60 from the stationary die member 40. The

end sections

122 and 123 are free of the die, and may be pulled out to clear the blank from the stationary portions of the die, this movement also slidingthe punches on the bed plates 30 into the position in which they are shown in Figure 2 and 5. The

blank may then be removed from the press, and

another blank substituted therefor and the hereinbefore enumerated steps in the operation repeated on that blank.

The particular design of the machine shown herein is made with the view of speedy operation so that the forging operation herein disclosed and the forging operation disclosed in my previously referred to Patent No. 1,925,860, may both be carried on with one heating of the blank, that is, the two forging operations are performed at such a speed that they are completed before the blank `has had time to cool sufficiently to necessitate its being reheated for the second forging operation.

While I'have chosen to show my invention ln connection with a preferred embodiment of it, I am aware' thatr there are many modifications that can bel made by ones killed in the art, and am vtherefore not to be limited to the specific disclo'surebut rather'only by the scope of the appended claims.

l. In a forging machine, a bed plate, apalr of L-shaped members disposed thereon with their short legs abutting, semi-circular forming blocks attached to and projecting outward from vsaid short legs parallel to the longer legsf'of said members and io said bed plate, a Wedge slot formed half in the'upper end of each of' said short legs, a dovetail projecting into said'wedge slot, a wedge, a dovetail on said wedge, means for moving said wedge into said slot to register the dovetail of the wedgewith thev dovetailof 'the members and to separate the members by sliding them on the bedplate, and mea-ns for moving said wedge outwardly of the slot to cause said dovetail connection between the wedge and members to slide the members on the bedplate inthe opposite direction to reabut said short legs.

2. In a forging machine, a base plate, a punch mounted .thereon and shaped to form the inside surfaces of the work that the machine is to fabricate, said punch being movable on the bed plate and expandable to form the work, a stationary die mounted on said base plate opposite said punch, clamping means associated with said die and located on opposite sides thereof, a complementary movable die mounted on said base plate on the opposite side of said punch and spaced therefrom to permit the work to be placed over the punch, complementary clamping means associated with said movable die and movable therewith, means for moving said movable die on said base plate to engage the work and then move the work, punch and movable die into engagement with the stationary die to thereby clamp and preliminarily form the work, spreading means into registration with which the punch is moved by said moving means, means for operating said spreading means to expand said punch and thereby force the work into the dies to form the same, and then to retract the spreading means, and means on said spreading means for automatically contracting said punch as the spreading means is retracted therefrom.

3. In a forging machine, a stationary die having an arcuate working face, a movable die having also an arcuate working face, said movable die being normally spaced from said stationary die, flanges on said dies overhanging said working faces, a pair of cooperating punches located between said dies and normally spaced therefrom and from said flanges to permit a blank to be placed over the punches, means for moving said movable die to register the same With said stationary die, said means also moving said punches and blank, said flanges overhanging the punches when the dies are registered to impart an initial bending to the blank, and means for expanding said punches into the dies to complete ihe shaping of the blank.

4. In a forging machine, a stationary die having an arcuate working face, a movable die having also an arcuate working face, `said movable die being normally spaced away from said stationary die, flanges on said dies overhanging said working faces, a pair of cooperating punches located between said dies and normally spaced therefrom and from said flanges to permit a blank to be placed over the punches, means on said punches for locatingv the blank thereon, means on said punches for increasing their thickness along the edges 4engaged by said blank, means for moving said movable die to register the same with said stationary die, said means lalso moving said punches and blank, said flanges overhanging the punches when the dies are registered to impart an initial bending to the blank, and means for expanding said punches into the dies to complete the shaping of the blank.

5. A machine for forming a channel shaped banjo casing from a metal blank having a central cylindrical portion and a pair of arms extending therefrom, said machine comprising a pair of channel shaped external blank forming dies, a pair of expanding internal blank forming dies between the external dies, said expanding dies being adapted to enter the cylindrical portion of the blank, means for moving the channel dies into working relation to the blank, means for holding the arms against twisting out of alignment, and means for initially expanding the internal dies inlo working relation to the blank after the ex- ,ternal dies have been brought into working engagement with the blank whereby the external dies hold the work during the entire forming operation by the internal dies.

6. A machine for forming a channel shaped banjo casing from a metal blank having a central cylindrical portion and a pair of arms extending therefrom, said machine comprising a pair of channel shaped external blank forming dies, a pair of expanding internal blank forming dies between the external dies, said expanding dies being adapted to enter the cylindrical portion of the blank, means for moving the channel dies into working relation to the blank, means for holding the arms against twisting out of alignment, and means for initially expanding the internal dies into working relation to the blank after the external dies have been brought into working engagement with the blank whereby the external dies hold the work during the entire forming operation by the internal dies, said internal dies being expansible within the external dies after the cylindrical portion of the blank has been formed into a channel section, to thereby expand the web and the flanges of the channel formed blank.

'7. A machine for forming a channel shaped banjo casing from a metal blank having a central cylindrical portion from which a pair of arms extend, said machine comprising a pair of channel shaped external blank forming dies, a pair of expanding internal blank forming dies, means for moving the end anges of the external dies into gripping relation with the central cylindrical portion of the blank, and means for then expanding the internal dies into the channel dies to form the central cylindrical portion of the blank between the dies into a channel shape, said external dies being maintained in working relation with the blank throughout the working range of the internal dies.

8. A machine for forming a channel shaped banjo casing from a metal blank having a central cylindrical portion and a pair of arms extending therefrom, said machine comprising a pair of external blank forming diesl and a pair of internal blank forming dies, said pairs of dies being adapted to receive the central cylindrical portion of the blank between them, means for moving the external dies towards one another to bring them into engagement with the work, means for holding the arms against twisting during the Working operation, and means for expanding theinternal dies within the cylindrical portion of the blank to fold that portion of the blank between the internal and external dies while holding the arms against twisting out of alignment, the external dies being in abutment with the cylindrical portion of the blank upon the initiation cf the working operation of the internal dies to inhibit dissymmetrical stretching of the blank.

9. In a forming machine for forming a channel shaped banjo casing from a metal blank having a central cylindrical portion, means for rst folding the cylindrical portion of the blank into a channel section and then expanding the section to stretch the web and the flanges of the channel, said means comprising cooperating internal and external dies, means for first moving the external dies into gripping relation to the work, and

means for then expanding the internal dies into the external dies to form the cylindrical portion of the blank into a channel shape, said internal dies being then expanded within the external dies by an additional amount approximating the width of the flanges to press the flanges between the dies inwardly of the blank.

10. A machine for forming a channel-shaped banjo casing from a metal blank having a central cylindrical portion and a pair of arms extending therefrom, said machine comprising channelshaped external blank forming dies, expanding internal blank forming dies between the external dies, said expanding dies being adapted to receive the cylindrical portion of the blank, means for moving the channel dies into working relation to the blank, means for holding the arms against twisting out of alignment, means for expanding the internal dies into Working relation to the flange and continuing the expansion to force the blank into the channel of the external dies, said last named means including means for increasing the height of the internal dies, and means for retracting the internal dies and decreasing their height in order to permit withdrawal of the Work from the dies.

GEORGE SPATTA.

ICO