US3068928A - Rapid cycle radial draw forming machine - Google Patents

Description

Dec. 18,1962

R. F. DE MARCO ET AL RAPID CYCLE RADIAL DRAW FORMING MACHINE Filed April 7, 1960 5 Sheets-Sheet 1 INVENTOR5. P05527- D'MAEc'O plus J. NAsvYr/.s BY

l 4:* AHORA/Ey Dec. 18, 1962 R. F. DE MARCO ETAL 3,068,928

RAPID CYCLE RADIAL DRAW FORMING MACHINE Filed April 7, 1960 Dec. 18, 1962 R. F. DE MARCO ETAL 3,068,928

RAPID CYCLE RADIAL DRAW FORMING MACHINE 5 Sheets-Sheet .'5

Filed April '7, 1960 INVENTORJ'.

P05527 E 75 MARCO v if A Trae/VEK Dec. 1s, 1962 R. F. DE MAR@ mL 3,068,928

RAPID CYCLE RADIAL DRAW FORMING MACHINE INVENTORS.

,9055er DE MARC@ P/us J. NAsvYr/s u2 A rme/vfx Dec. 18, 1962 R. F. DE MARCO EIT AL RAPID CYCLE RADIAL DRAW FORMING MACHINE Filed April 7, 1960 5 Sheets-Sheet 5 1NVENTOR5. 055?? E @5M/1ero P/as J. /vAsVyT/s BY g Jaw

A TTOENEK United States Patent Oiitice 3,068,928 Patented Dec. 18, 1962 3,068,928 RAPID CYCLE RADIAL DRAW FORMING MACHINE Robert F. De Marco, Mentor, and Pius J. Nasvytis, Cleveland, Ohio, assignors to The Cyril Bath Company, Solon, Ohio, a corporation of Ohio Filed Apr. 7, 1960, Ser. No. 20,689 7 Claims. (Cl. 153-32) This invention relates to a stretch forming machine and particularly to a stretch forming machine for forming elongated metal stock about a side face die of which the face has a rise and tall in an endwise direction.

The present machine is an improvement on the machine i ,disclosed in a copending application of Robert F. De

their relative senses for convenience in describing relative positions of parts, and not as absolutes.

A general object of the present invention is to provide a rapid cycle stretch forming machine of simple Vconstruction in which the heavy and expensive .power applying mechanisms heretofore required have been reduced to -a minimum.

A principal object is to provide a stretch forming machine employing a stretch head carried on a swinging arm which is adapted to swing about an upright axis so as to swing the stock about upright axes toward the side face of the die and concurrently to swing the stock about a horizontal axis so that head rises and falls and thereby "lifts and lowers the stock to conform it to ,the rise and fall of theside face of the die endwise of u the die face.

Various other objects and advantages of the inven- I tion will become apparent lfrom the following description -wherein reference is made to the drawings in which:

FIG. 1 is a front elevation of themachine embodying the principles of the present invention;

FIG. 2 is a top plan View of the machine illustrated in FIG. .1, the stretch forming mechanism on the left hand arm being omitted for clearness in illustration;

FIGS. 3, 4, and 5 are enlarged fragmentary cross sectional views taken on the lines 3 3, 4-4, and 5"-5,

'.respectively, of FIG. l;

FIGS. 6 and 7 are a side elevation and a right end elevation, respectively, of the stretch forming gripping head and mandrel mechanism for the left hand arm of FIG. l;

FIGS. 8 and 9 are a side elevation and a left end ,elevation of the stretch forming gripping head and `mandrel mechanisms of the right hand arm in FIG. l;

and

FIG. l is a pneumatic flow control diagram for the present machine.

Referring to the drawings, the preferred embodiment of the machine includes a horizontal frame 1 on which `is mounted a platform or table 2 which supports a side face die 3 with the side face generally upright. Mounted on the frame 1 is an upright sleeve 4 in which an upright pivot post 5 is mounted for rotation about Vits axis. `Carried on the pivot post 5 are transverse or horizontal lcoaxial pivots 6 which support a' rocking connector 7 for terms horizontal, vertical and the like are used in rocking about their common axis and for rotation with the upright pivot post 5.

An arm 8 is iixedly secured to the connector 7 and extends generally horizontally outwardly from the axis of the pivot post 5 and in a direction generally endwise of the side face of the die 3. Fixedly connected to the arm 8 is a driving arm or bracket 9 which extend-s generally radially from the axis of the pivot post 5 and which, at its outer end, is provided with a suitable yoke 10.

Carried on the frame 1 is a suitable anchor bracket 11 to which a reversible pneumatic piston and cylinder as'- semblage 12 is pivotally connected for swinging. about an axis parallel to the axis of the post 5. 'Ihis assemblage includes a cylinder 13 in which a piston 14 having a rod 15 is reciprocable. The rod 15 is pivotally connected by an upright pivot 16 to the yoke 10 so that upon ex :tension of the assemblage 1'2, the arm 8 is swung to its forward or starting position and upon retraction of the assemblage 12 the arm is swung from its forward position toward a rearward position for laying the stock along the side face .of the die.

As mentioned in the objects, the machine is particularly adapted for stretch forming stock along the die side face' which undulates or has a rise and fall endwise at some preselected portion between its ends. In order to cause the stock being stretch formed to follow the rise and fall of the side face of the die, the arm 8 is provided with a suitable roller 20 which` rides on a track 21 carried on the frame 1 and whichis'held down by a `suitable overhanging guide track 22. By virtue of the rise and fall of the track 21 and guide track 22, the arm V8 is made to rise and fall by rocking about theI common axis of the pivots 6 as it is swung from its forward to its rearward position and returned by means of the assemblage 12.

In order to apply stretch forming tension to` the stock endwise of the stock, the arm is provided with a suitable gripping and mandrel inserting mechanism which is movable endwise of the arm 8.

For supporting the mechanism, later to be described, for movement endwise of the arm 8, acarriage 23 is mounted on the arm 8 on suitable slideways 24 forV sliding movement endwise of the arm 8. Thecarriage is moved along its slideways by a 'suitable tension cam track 25 which is mounted on the frameV 1. The cam track 25 is engaged by a suitable cam roller 26 mounted on the under side of the carriage" 23. A compression spring 27 is interposed between a bracket 28 on the carriage and a bracket 29 on the arm and yieldably urges the carriage in a direction so as to hold the cam roller 26 in firm rolling engagement with the operating face of the cam track 25. Thus, upon swinging of the arm 8 about the axis of the post 5, the cam track -25 causes the carriage to' move the gripping and mandrel inserting mechanism endwise away from the table 2 and to permit the mechanism to return under restraint toward the table 2 the distances which provide the required tension on the stock being formed.

The gripping and mandrel operating mechanism, mounted on the carriage 23, is arranged for gripping one end of the stock after inserting a mandrel into the stock for internally supporting the gripped end. The mandrel is to prevent collapse of the stock by the gripping pressure 'and for support of the stock internally for a distance beyond the portion gripped to prevent buckling during stretch forming.

As best illustrated in FIGS. 1, 6 and 7, this mechanism, indicated generally at 30, is mounted on the carriage 23 for swinging about an upright axis. For this purpose, the carriage 23 is provided with an upright bracket 31 having yoke arms 32 which receive and are pivotally 34 in alignment with the mandrel.

connected to a suitable tongue 33 fixedly secured on a swinging stretch head and mandrel support 34. The support 34 is provided with a skid pad 35 which engages an upwardly facing complementary skid pad 36 on the carriage 23. Thus, the swinging support 34 may swing about an upright axis for maintaining proper alignment with the axis of the stock being formed.

Mounted on the swinging support 34 is a stock gripping stretch head, indicated generally as 37. The head comprises vessentially a stationary jaw 40 adapted to lit the cross sectional contour of the stock S to be stretch formed and a movable jaw 41 which is adapted to be moved relative to the jaw 40 so that the jaws cooperate in rmly clamping the stock with the mandrel inserted therein, `whereby the stretch forming tension can be applied to die stock.

In order to support the jaw 41 for movement toward and away from the jaw 40 and for moving the jaw by a suitable power means, the jaw 40 is mounted in between suitable yoke arms y42 which are pivotally connected by a horizontal pivot 43 to the swinging support 34. The jaw 41 is provided with suitable lineal guides 44 which operate in guideways 45 extending endwise of the yoke arms 42 for guiding the jaw for proper cooperation with the jaw v40. To 'move the jaw 41 toward and away from the jaw 40, the jaw 41 is connected by a toggle pin 47 to a link 48 which, in turn, is connected to a toggle pin 49'. The toggle pin y49 is connected to a cooperating toggle link 50 `which is pivotally connected, as indicated at 51, to the arms 42. The pin 49 is connected to the rod 52 of a piston 53 which is operable in acylinder 54 of a reversible pneumatic piston'and cylinder assemblage, indicated generally Yat 55. The assemblage 55 is connected by a pivot '56 to the support 34 so that it can rock about a horizontal axis and thus accommodate itself for proper angularity with respect to the 'toggleliriks 48 and 50 which operate the jaw 41.

The gripping head and mandrel inserting mechanism also includes a mandrel guide 60 which is arranged at the outboard end of the jaws 40 and 41 in alignment therewith. The guide `60 is mounted in xed position on the support 34. A mandrel 61 having a rigid non-compressible head 62 is mounted for sliding movement in the guide 60 so as .to move to an extended position between the jaws and to a retracted position to the outboard end of the jaws. A suitable reversible or spring return pneumatic piston and cylinder assemblage 63, including a cylinder 64 and a piston 65, having a rod 66 connected to thehead 62 of the mandrel is carried on the support Thus the mandrel can be retracted by the assemblage `63 from between the vjaws 40 and 41 endwise of the stock S while the stock is being inserted and, after insertion of the stock between .the jaws, can be inserted into the stock endwise preparatory to closingr the jaws. The head 62 of `the mandrel is, as mentioned, very rigid so that when the jaws are operated by the toggle to apply clamping pressure to the stock, the head reinforces the stock internally and prevents crushing or distortion of the stock.

The mandrel 61 may be relatively short or long, depending upon the distance to which it is to be inserted in the stock beyond the inboard end of the jaws. This, in turn, depends on the distance the bends in the stock are to be from the end. 1In the form illustrated, a relatively short mandrel is all that is required.

With the structure thus far described, it is apparent that the stock can be held in fixed position relative to the die 3 at a location which is in spaced relation to its left end. The stock can be stretch formed, without being distorted in cross section, both in a direction forwardly and rearwardly of the machine and vertically thereof by inserting the mandrel, gripping the stock, with the mandrel head therein, in the jaws 40 and 41, and swinging the arm 8 from the forward position to a rearward position while the arm 8 is moved up and down as well as forwardly and rearwardly.

Quite generally, however, it is desirable to form the stock along the side face of a die which recedes from some preselected location intermediate its ends, usually from its mid-portion to the rear of the die and also from a higher position at said location to a lower position towards the ends. Generally, the piece to be formed is symmetrical and the peak of the side face is at the longitudinal mid-portion of the die face. In such instances, generally, the axis of the pivot post 5 is arranged at this location which is indicated by the letter X in FIG. l, and the die slopes downwardly from the portion X in both directions towards the ends and also slopes rearwardly of the apparatus from the portion X.

ln order to form stock about a die of this nature, an additional or second arm is provided. Referring to FIGS. l, 2 and 4, a suitable supporting member 70 is mounted `on the frame 1. Extending upwardly through the surface of the member 70 is an upright pivot 71 by which a rotatable support 72 is pivotally connected to the supporting `member 70` for rotating about the upright axis. Mounted on the rotatable support 72 for rocking about a horizontal axis is an arm 73, the arm being'pivotally secured to the support 72 by a suitable horizontal pivot 74. Mounted von the arm 73 is a stock gripping head, indicated generally at 75, and a mandrel supporting and operating mechanism, indicated generally at 76. The stock gripping mechanism is best illustrated in FIGS. A8 and 9. This `mechanism is substantially the same as the mechanism 30 on the arm 8. It comprises a stationary gripping jaw `77 and a movable gripping jaw 78, the jaw 77 being tixedly mounted on a supportingjplate 79' which is tixedly positioned on the arm 73. The jaw 78 has'suitable guides 80 which voperate in the guideway 81 in a pair of yoke arms 82. The yoke arms are pivotally connected by a 'pivot 82a to the plate 79. Connected to the movable jaw 78 by a toggle pin 83 is a link 84 which, in turn, is connected by a toggle pin to a link 86. The link 86 is connected to a piston rod 88 of a piston 89 operable in a cylinder 90 of a reversible pneumatic piston and cylinder assemblage 91. This piston and cylinder assemblage 91 is connected by a horizontal pivot 92 to the plate 79 so as to align itself properly during expansion and retraction of the toggle.

Mounted on the plate 79 is a hollow support and guide 93 which receives and guides a mandrel 94 endwise between the jaws 77 and 78 into the stock. A mandrel 94 is provided with a rigid head 95 near the outboard end of the jaws 77 and 78. The mandrel is slidable endwise through the hollow support and guide 93. The guide 93 is provided along one edge with a slot 96 through which extends a pedestal 97 which supports the head 95 within the guide 93. The pedestal 97 is mounted on a sliding carriage 98 which is connected to a piston rod 99 of a reversible pneumatic piston and cylinder assemblage 100, including a piston 101. Upon extension of the piston rod 99, the mandrel I94 is moved to a retracted position and upon retraction of the piston rod 99, the mandrel 94 is moved through the end of the stock to an extended position to dispose the head 95 beyond the locations to be curved. Generally, the mandrel 94 is the longer mandrel and extends to or very slightly beyond the I.bend at the mid-portion of the die face for supporting the stock internally at the Ibend at its mid-portion. The head is non-compressible and fits accurately the interior of the stock and prevents distortion and collapse of the stock by the jaws, and assures firm clamping pressure.

Since the support 72 is rockable about horizontal and vertical axes, it can be aligned so that, in the starting position, the line of pull between the jaws 40 and 41, on the one hand, and the jaws 77 and 78, on the other, is lineal and slopes downwardly alongside the die face toward the jaws 77 and 78 at that portion of the die face from the line X in FIG. 1 toward the end of the die face adjacent the jaws 77 and 78. Thus, as illustrated in FIG. 1, the stock is aligned vertically throughout the distance from its right hand end and to the preselected position or mid-portion at line X with the side face of the die it is to engage, but from the portion at line X toward its left hand end the stock continues on a rising straight line entirelyV to its left end, then rising above the level of the left .portion of the side face which it is to engage. The stock is also close to the right end of the side face. As a ,result of this action, very little swinging and rocking movement of the arm 73 is required in the forming operation. However, this length of stock is to be clamped by the jaws at its opposite ends preparatory to being engaged with the side face of the die. Yet the side face of the die slopes rearwardly as well as downwardly from the preselected or mid-portion X toward the ends. Accordingly, the straight length of stock extending from one set of jaws to the other set makes a predetermined angleA with the rightA hand portion of the forward face of the die adjacent the right hand gripping jaws 77 and 7S and a greater angle B relative to the left hand portion of the `forward face. The jaws 77 and 78 preferably are arranged close to the axis of the pivot 71 so that the stock is gripped just beyond the right hand end of the die face, yet clearing the die face. It can be swung clockwise in FIG. l. When the stock is swung clockwise by the swinging of the arm 8 to the rear, the stock will rst be brought into contact with the right hand end of the face of the die and laid on the face progressively therefrom to the mid-portion at line X and then, thereafter, progressively from the line X to the left end of the die. However, this angle at A at the starting position would cause an abrupt Ibend to the stock adjacent the jaws 77 and 78 except for the fact thatthe jaws are near the axis of the pivot 71 and the support 72 can swing about that axis.

When the stock is swung into engagement with the right hand portion of the die face, the jaws 77 and 78 and the mandrel 94 swing so that the stock and mandrel become substantially tangential to that end of the die face.

However, even the weight of the arm 73 and its supported mechanism would tend to impart a severe binding stress to the stock at this point. Accordingly, means are provided to assure that the arm 73 swings at a different rate than the arm 8, though swinging in the same clockwise direction, and furthermore swings through a lesser angle than the arm 8 during the entire forming operation. 'For example, the arm 8 will swing about the axis of its pivot post 5 through the angle B from starting to final position, whereas the arm 73 need swing only through the much lesser angle A.

In order to control this operation so that the arm 8 swings both faster and farther than the arm 73, a suitable tie member 105 is pivotally connected at 106 to the bracket 9 and thereby to the arm 8 so that the end of the tie member 10S moves with the arm 8 during the swinging movement thereof on the forming and return strokes. The member 105 is connected, as indicated at 107, to a suitable bracket 108 which is rigid with the arm 73. Accordingly, upon swinging of the arm 8 about the axis of the pivot post 5, the arm 73 is swung about the axis of its pivot 71. However, the point of connection at 107 is farther from the axis of the pivot post 71 than the -point of connection 106 is from the axis of the pivot 5. Therefore, depending on the degree of difference in the length of these radii, the arm 73 moves through a less angle than the arm 8. The arm 73, therefore, yis constrained to swing at a different speed at all times than the arm 8 and also to swing in the same direction angularly about its axis as the arm 8.

Mounted on the frame 1 is a suitable adjustable stop 110 -which is positioned to be engaged by the support 72 and which stops the swinging of the arm 73 in a position 6 in which itholds the stock tangent to the Iside face at the right end of the die face 3. A suitable lost motion connection is provided in the tie member and a heavy spring 112 is interposed so that, when the stops and support engage, any additional slight movement of the arm 8 and its bracket 9 can be relieved.

In order to operate the various mechanisms, a suitable source of positive pressure air is provided and is connected to suitable reversing and cut-olf valves of the respective piston and cylinder assemblages. Since all of these valves'are the same in type and operation, only .one will be described in detail.

The valve 121 is connected by the pressure line 122 to the `source 120 and is connected to the atmosphere at 123. This valve is connected to opposite ends of the cylinder 63 and, in intermediate position, connects the ends of the cylinder together for servicing and repairs. At one of the operating positions, indicated at 124, it connects the assemblage so as to cause retraction of the piston rod 66 and at the other operating position, indicated at 125, it causes the extension of the piston rod 66. Valves 126, 1.27, 128 and 129, all of the same type, are correspondingly connected to the assemblages `55, 12, 91 and 100,

respectively. Each ofthe valves is operable independently of the others, and preferably each is operable by suitable solenoids, such as indicated at 130 on the valve 121, so that the valves can be operated from a common control panel.

It is apparent from the foregoing description that the machine is relatively simple in structure and effective for rapid cycle bending of stock which must be curved concurrently both in a horizontal plane and in a vertical plane Ibecause of the rise and fall of the die face endwise. Furthermore, the stock can be formed without imposing any severe bends adjacent the ends of the die inasmuch as the arms are tied together for movement at different speeds in the same direction. The degree of stretch can be accurately controlled by the cam track. These features render the machine particularly suitable for forming large numbers of identical parts.

Having thus described our invention, we claim:

l. In a stretch forming machine, a frame, a horizontal support thereon, a side face die in fixed position on the support, a lpair of arms, supporting means mounting the arms on the frame for swinging about upright axes, respectively, power operated stretch forming means including gripping heads on the arms, respectively, adapted for connection to opposite ends of a length of stock for applying endwise tension to the stock, power operated means connected to the arms and operative to swing the arms about their respective axes while constraining one arm to swing at a different angular velocity than the other arm.

2. The structure according to claim 1 wherein said power operated means constrains one of the arms to swing at a different speed from the other arm while the arms are swinging in the same direction.

3. The structure according to claim 1 wherein said power operated means includes a tie member operatively connected at its ends to the arms, respectively, the connection with one arm being a greater distance from the upright axis of said one arm than the 'distance at which the connection of the member with said other arm is from the axis of said other arm.

4. |In a stretch forming machine, a frame, a horizontal support thereon, a side face `die in fixed position on the support, a pair of arms, supporting means mounting the arms on the frame for swinging about upright axes, respectively, power operated stretch forming means including gripping heads on the arms, respectively, adapted for connection to opposite ends of a length of stock for applying endwise tension to the stock, said side face die sloping endwise downwardly in each direction from a predetermined location thereon toward its ends, additional means on one arm maintaining the arm in positions in which its associated gripping head is in a lower position than the gripping head of the other arm with the line of pull between the heads aligned with the side face of the die from the predetermined location on the die face to said lower head, and additional supporting means supporting the other arm for up and down movement for lifting and lowering its gripping head during swinging of the other arm, and control means for controlling said up and down `movement so as to lay the stock on the die face between said predetermined location and said other head after it has been laid on the die face between said predetermined location and said one head.

5. `In astretch forming machine, a frame, a horizontal support thereon, a side face die in xed position on the support, a pair of arms, supporting means mounting the arms on the frame for swinging about upright axes, re-

spectively, power operated stretch forming means including gripping heads on the arms, respectively, adapted for connection to opposite ends of a length of stock for applying endwise tension to the stock, said arms being positionable in a starting position such that the line of pull between the heads is lineal and spaced from the side face, said side face has a horizontal component of slope away from said line in both directions from a predetermined location on the die face toward the ends of the face, and means interconnecting the arms so that they swing concurrently in the same direction of rotation about their respective axes, one arm through a lesser angle than the other and thereby rst lay the stock on the die face lprogressively from one end adjacent said one arm to said predetermined location and thereafter progressively from said predetermined location to said other end of the face, adjacent the other arm.

6. The structure according to claim 5 and further including stop means for arresting continued swinging of said one arm in the same direction after the stock has been ylaid on the -die face from said one face end to said predetermined location.

7. The structure according to claim 5 wherein the means interconnecting the arms include a resilient lost motion device.

References Cited in the file of 'this patent UNITED STATES PATENTS 2,713,376 Bath July 19, 1955 2,830,644 Walker et al. a Apr. 15, 1958 2,880,780 IMackey Apr. 7, 1959 2,881,821 -Maize et al. Apr. 14, 1959 2,887,143 Ahonen May 19, 1959 ...LNH

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