US2940498A

US2940498A - Pressure-exerting apparatus

Info

Publication number: US2940498A
Application number: US611675A
Authority: US
Inventors: George A Helle; Raymond K Neal
Original assignee: Chance Vought Aircraft Inc
Current assignee: Chance Vought Aircraft Inc
Priority date: 1956-09-24
Filing date: 1956-09-24
Publication date: 1960-06-14
Anticipated expiration: 1977-06-14

Description

June 14, 1960 G. A. HELLE ETAL 2,940,493

PRESSURE-EXERTING APPARATUS Filed Sept. 24, 1956 2 Sheets-Sheet 2 INVENTORS. 6 George A. He/Ae Raymond K Nea/ United States Patent PRESSURE EXERTlN G APPARATUS George A. Helle, Dallas, and Raymond K. Neal, Grand rairle, Tex., assign'ors to Chance Vought Aircraft, Incorporated, Dallas, Tex., a corporation of Delaware Filed Sept. 24, 1956, Ser. No. 611,675

12 Claims. (Cl. 153-21 This invention relates to a pressure-exerting apparatus, and more particularly to such an apparatus employing a ram and providing a mounting means therefor.

Briefly described, the invention comprises a ram and a mount therefor. The ram and mount are respectively of designs permitting their construction in the form of units of relatively small size and light weight in consideration of which the ram is capable of an extremely high pressure output. Of a pneumatic-hydraulic type, the ram has an air cylinder or barrel provided with a piston which is axially movable therein, and mounts coaxially, in one of its ends, an end of a hydraulic cylinder or housing which is provided with a piston extendible outwardly from the housing for applying pressure on a given object. The hydraulic piston has an axial cavity which opens into the hydraulic housing, and this cavity, together with adjoining space within the housing, is filled with a liquid. A plunger attached at one of its ends to the air piston extends from the air cylinder through a fluid-tight pack ing in an opening in the inner end of the hydraulic housing into the liquid-filled interior of the latter. For moving the air piston, valve means are provided on the unit for the selective direction of fluid under pressure to either end, as desired, of the barrel, said means being provided with a swivel fitting to allow rotation of the unit without kniking or fouling of an air line (or equivalent) connected thereto. When extended from the barrel by movement of the air piston, the plunger enters the cavity in the hydraulic piston and displaces fluid therefrom, thereby causing extension of the hydraulic piston and, as the latter encounters substantial resistance, building up an output pressure far in excess of the pressure of fluid supplied to the barrel. Means are provided on the ram for the adjustable mounting of the ram on a component of the mount. The mount is a quadrilateral structure having a first end member which engages a body against which, directly or through one or more other bodies, force is to be applied by the ram; a pair of lateral members rigidly connected at ends thereof to respective ends of the first end member and extending outwardly beyond an edge of the body to which pressure is to be applied; and a second end member which is pivotally mounted at one of its ends on the outer end of one of the lateral members. The second end member has mounting provisions which receive the ram at the mounting means provided on the latter, is pivotable to a position wherein it bridges the ends of the two lateral members for bringing the ram into working position relative to the object against which pressure is to be applied, and may be pivoted out of that position for moving the ram out of the way and for providing easy access to the area of the object contactable by the ram. Means are provided for locking the second end member in its position of bridging relation to the lateral members, and the mount may be provided with a stop for limiting the range of pivoting of the end member out of its first, bridging position. The ram and mount are of value in a multitude of operations where the application of pressure by the ram against a part is useful:

Federated June 14, 1960 coining, dimpling, punching, and the forming and blanking 'of small parts are a few among many ready examples. By way of still another example, the invention is most useful for joggling operations, and in one specific embodiment may further comprise a stretch forming die, gripping jaws, and a joggle block for use in the stretch forming and joggling of parts. Although stretch forming and joggling of parts has previously been performed by other machines as well as by hand, the invention further pro- -vides a novel device for stretch forming and joggling a part which is particularly advantageous in that the possibility of the mislocation of joggles is practically elimi= nated the joggling operation produces no distortion or the part away from the general curvature irnposed there on by the stretch forming die, spring-back of the part after jogg'ling is eliminated or greatly reduced, and much time is saved over previously used methods. The device makes possible the stretch-forming of a part over a stretch forming die face provided with a joggle, and the intro duction of a joggle into the part by placing a joggle block of suitable proportions against the part and applying pressure to the block for forcing the part into conformity with the joggle in the die face. To insure proper yielding of the material of which the part is composed in order that he joggle may be introduced without distortion of the part from its overall stretch-formed shape, the elongating forces applied to the part in accomplishing the stretch forming operation may be left on the part during the joggling operation, or a fractional portion of these st'retching forces may be relaxed before joggling, enough being retained to prevent distortion.

It is, accordingly, a major object of the present invention to provide a pneumatic-hydraulic rain of comparatively small size and weight and capable of the exertion of great contact or pushing forces.

Another object is to provide a ram such as specified above which is energizable by a fluid supplied from an outside source at a relatively low pressure.

Still another object is to provide a ram of the sort stated above which may be rotated about its own axis without kinking or fouling of a fluid-supplying line attached thereto, and which is supplied with convenient and effective means for securing the same in a suitable mount.

Yet another object is to provide a ram which has means for the selective mounting of the same in fixed or movable relation to a part against which pressure is to be applied.

A further object is to provide, for a ram, a mount in which the ram is axially adjustable.

A still further object is to provide a mount such as thus far stated which readily permits adjustment of the ram, relative to an object against which pressure is to be applied, in two planes in addition to the plane of the above-mentioned axial adjustment, and which permits ready movement of the ram from a stable position allowing easy access to the object against which pressure is to be applied to a working position in which the ram confronts, in close proximity, the pressure-receiving object.

An additional object is to provide a device for' stretch forming and joggling which makes possible the more rapid production of properly shaped parts and tends to reduce the wastage of time and materials accompanying the rejection of improperly formed parts.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawings which illustrate an embodiment of the invention.

Reference is now made to the accompanying drawings,

in which:

Figure l is a perspective view showing the ram, stretch forming die, mount for attaching the ram on the die,

joggleblock, jaws, and stretch formed part ready for the joggling operation; 6

Figure 2 is an orthographic view from directly above of fragments of the joggleblock, die, and joggled part;

a Figurev 3 is a perspective view more completely illustratingftheparts of the mount; and r Figure 4'is a perspective view of'a typical end of the first end member engaged withone of the lateral members;,;y ,I Figure ,5 is a view taken along line V-'V'of Figure 4 and omitting the lateral member; and p Figure 6 is a longitudinal, partially sectionalyiew of the 7 Referring now to Figure 1, a stretch forming die 10 is rigidlyattached by any appropriate means to a table or support ,12and, has an edge or face 13 whosecrosssectional :cont'our matches the cross-sectional contour of a part 14"to be formed, on the die and' whose curvature transversely of the die (i.e., along the length of the die face 13). corresponds to a desired curvature in the part after shaping of theilatter. For purposes of illustration, the part 14 is shown'to be of approximately Z-sectional shape, and the die face 13 accordingly has, an upper vertical portion 44 which is concentric with a larger-circumference, lower, vertical portion 45 connected to the upper 'portion 44 by a horizontal portion 46 (Figure 2) which underlies a corresponding horizontal portion 47 of the part 14. The curvature of the finished part 14, as shown in Figure 2, is interrupted by an ofiset portion or joggle 15, and, for forming this joggle, a corresponding joggle 16 is formed in the die face 13. Two

jaws

17A, 17B (Figure 1) are providedfor grasping the unforrned part 14 at its ends, engaging a side of the part against the die face 13, and subjecting the part to elongating forces whilewrapping it around the die face, thus forming it to a curved contour determined by' the shape of the die face. A joggle block 18, supported and guided by any convenient means, such as'being well known in the art, ,has a forward face 19 (Figure 2) contoured to complement the joggle 16 of the die face 13 and a rear face 20 on which'pressure may be applied for forcing the part 14 into conformity with the die face joggle 16 on the one side and the joggle block forward face 19 on the other, thus introducing into the part the joggle V shown in Figure 2. The stretch forming die 10 has, preferably at a point radially aligned with the joggled portion 16 of the die face, a hole 21 which extends entirely through the die in a direction preferably normal to a radius'of the die face 13 in the region of the joggle 16.

Further pertinent details of the mode of construction and,

end 27A shown) projecting respectively above and below.

the die 10. Rigidly attached at an end thereof to the upper end of the first end member 23 is a first (or upper) lateralmember 25 whose other end extends outwardly beyond the die face 13. A second (or lower) lateral member 26 has an outwardly extending end protruding beyond the die face 13 and an inner end, not shown in Figure "l; which is rigidly attached to the lower end of the first end member 23. A second end member 24 is 3 pivotally mounted, as by aligned pins 28, at one of its ends on the outwardly extending end of the upper lateral member 25, and is pivotable to a position wherein it bridges or connects the outer ends of the two

lateral members

25, 26. Means for locking the second end member 24 in its bridging position between the

lateral members

25, 26 are provided, the locking means of the example comprising a latch 29 pivotally mounted bya pin 30 at one of its endson the second end member and at its' other end being engageable with a portion of the outer end of the lower lateral member 2 6. For receiving and holding the ram, the second end member 24 is provided with a hole 32 (best seen in Figure 3) of suitable size which is formed along an axis extending between the vertical centerlines of the two

end members

23, 24 and which, preferably, is .tapped.

, Returning to Figure '1, the pneumatic-hydraulic ram 34 has a cylindrical portion 33 received bythe; hole 32 formed in the second end member 24. Where, as is preferable, theend member hole 32 is tapped, tl 1is'cylindrical portion 33 is threaded for engagement of' the threads formed therein.' With the end'membe'r latch '29 engaged with the outer end of the'. second lateral member 26, the axis of the ram 34 preferably is aligned for intersecting the axis of the first end member'23, and the outer end of the rams hydraulic piston 35 lies near or against the back face of the joggle block 18. The spacing of the piston 35re1ative-to the, joggle block 18 (hence,'to the die face 13) is readily varied by rotating the ram 34 in the second .end'member 24 and thus, by action of the threads of: the ram cylinder portion 33 and threads in the hole 32 tapped in thesecond end member 24, effecting changes of position .of the ram 34 along its axis in the secondiend'member 24. Outsidepower is supplied tothe ram 34 forf energization thereofthrough an ,air hose 3.7 which is connected to an air valve 38 mounted on the outer end of,the.ram;.then energized for extend- 7 ing the hydraulic piston 35, theram 34 applies pressure, through the :joggle block 18 and part 14, to the edge or face 13 of the die; 10; Connection of the :hose 37 to the valve 38 is through a-swivel fitting 39 which remains substantially fixed relative to the mount 22 when the ram 34 is rotated in the latter and thus, prevents fouling and kinking of the hose 37; j b b To allow for lateral adjustment of the ram 34 relative to'any. chosen point on the die'facei13, it is preferably that the first end member 23 be made in'cylindrical form inforder that it may be rotated inthe hole 211 provided inthe die 10, thus, allowing pivoting of the mount 22 and ram 34 in a plane normal to the axis of the first end member 23.. For vertical adjustment of the ram 34 relative to the die 10, it is desirable that the first end member 23. be readily. adjustable axially 0f;the hole 21 provided therefor in the die. This is, accomplished,

in theexample, by making the first end member 23 in two parts, namely an outer bushing 40 (which serves as. a means'for preventing axial motion of the first end member 23, in a'jdownward direction, relative to the die 10) and 'an inner. cylindrical member '41, *whose construction and. operation will now be described.

The bushing 40 is of cylindrical form, has a smooth outer surface snugly and rotatably received in the hole 21 in'the die 10,,is provided with acylindn'cal, tapped inner surface (to be described),,and at its upper end has an outer peripheral collaror shoulder '42 .whose diameter is larger than that of the hole ,21. Shown in Figure l as raised from the upper surface of the die 10 in order that the diehole 21.may appear'in the drawing, the shoulder 42 normally rests against the die 10 and, by striking the latter, limits insertion of the bushing 40 into the die lllbeyond a proper depth; :1 r

The inner member41 elongated body of circular cross-section which is provided with external threads 43 snugly engagingthe above-mentioned threads tapped interiorly 'of the bushing 40.; With the shoulder 42 against the'die 10, rotationof the bushing 40 in the hole 21 and about the inner member 41 results in vertical displace ment ofthe inner member .41 and hence of the ram 34 in a directiondeterminedbythe direction of rotation of the bushing. i Referring to Figure 3,.the firstend member 23 has a firstend' 27A. extending "above and a second end 2713 extending below the dieJlO. The bushing 40pis shown partially cutaway to reveal the threads, 481therein which match and engage, theabovementioned inner member threads 43. The upper and lower

lateral members

25, 26 may be rigidly and non-adjustably attachable to respective ends of the inner member 41, but, in order to permit adjustment of the interval between the inner member 41 and the second end member 24, it is desirable that the

lateral members

25, 26 be rigidly attachable to the inner member 41 at selected points along their lengths. To this end, the inner member 41 is provided, as shown in Figures 3, 4, and 5, with a pair of

parallel slots

49A, 49B cut into opposite sides thereof near its upper end, the axes of the slots preferably being normal to the lengthwise axis 50 of the inner memher, the axis 51 of the near-side slot 49B being shown in the drawing. At its inner end, and for at least a substantial interval along its length, the upper lateral member 25 comprises a parallel pair of

arms

52A, 52B whose cross-sectional shape and size is such that they are snugly and slidingly received into the corresponding cavities or slots 49A, 45B of the inner member 41. Because of their snug fit in the

slots

49A, 49B, the

arms

52A, 52B cannot experience any change in their angular relationship to the inner member 41. A hole 53 is provided near its inner end in each

arm

52A, 52B, and a plurality of additional, similar holes are provided along the length of each arm, the holes 53 of the arm 52A being aligned in pairs with corresponding holes 53 of the arm 52B, successive pa rs being uniformly spaced by any convenient interval. The holes 53 are formed around centerlines perpendicular to the inner member axis 59 and to the slot axis 51. Meanwhile, at least one hole 54A is provided through the upper end of the inner member 41 in such position that its ends open into the slots 49A, 493. This hole 54A is formed about an axis 98 parallel to the centerlines of the upper lateral member holes 53 and perpendicular to both the first end member axis 50 and the slot axis 51, and is vertically oriented so that any one of the lateral member holes 53 may be brought into register therewith by sliding the upper lateral member 25 in an appropriate direction in the

slots

49A, 49B. With any desired pair of holes 53 in the upper lateral member 25 aligned with the inner member hole 54A, the lateral member 25 may be rigidly fixed relative to the inner member 41 by inserting a pin 55A through the aligned

holes

53, 54A. Adjustment of the lateral member 25 in increments smaller than the interval between consecutive pairs of lateral member holes 53 is made possible by providing a second hole 54B through the inner member 4-1 at the slots 49A, 45B, the two inner member holes 54A, 54B being spaced apart by an interval which is, for example, one and one-half times greater than the interval separating consecutive pairs of holes 53 in the upper lateral member 25, the pin 55A being insertable through either of the inner member holes 54A, 54B as required. With this arrangement, the upper lateral member 25 is adjustable along its length, relative to the inner member 41, in increments of one-half the interval between successive aligned pairs of lateral member holes 53.

The lower end of the inner member 41 is provided with slots parallel and similar to the upper-

end slots

49A, 49B shown in Figure 4, only the near-side lowerend slot 563 being shown (Figure 3). The lower lateral member 26 is slideable in the lower slots (56B shown) in the manner stated above in connection with the corresponding

slots

49A, 49B of the upper member 25, is similarly of bifurcate form at its inner end, and is provided with aligned pairs of holes 57 along its length which lie parallel to and directly below corresponding holes 53 in the upper lateral member 25. The lower end 273 of the inner member 41 is provided with pin holes (not shown) which correspond in spacing and location to the pin holes 54A, 54B shown, in Figure 5, in its upper end 27A and receive, as selected, a pm 553 (Figure 3). By removing the two

pins

55A, 55B, the

lateral members

25, 26 may be slid in unison through the upper-

end slots

49A, 49B and lower-end slots (nearside slot 56A shown) to place the second end member 24 in a desired position relative to the die face 13 and first end member 23. Upon insertion of the pins 55A, 553 through aligned

holes

53, 57 and 54A or 54B in the lateral and

inner members

25, 26, 41, the

lateral members

25, 26 are locked relative to the inner member 41.

The pins 28 by means of which the second end member 24 is pivotally attached to the outer end of the upper lateral member 25 define the pivot axis of the second end member, 24 and, in the specific example, are preferably normal to the lengthwsie axis of the upper lateral member 25. From its first, bridging position shown at 24, the second end member may be pivoted so that its lower end moves away from the lower lateral member 26 along an are 60 to a second position 24A, and with the ram 34 installed, as previously described in connection with Figure l, in the tapped hole 32, the ram also is moved therewith along a comparable arc in a direction away from the die face 13 (Figure 1). With continued reference to Figure 3, the length of the are 60 is a matter of choice, but should be long enough so that the ram is moved well away, along an arcuate path, from the joggle block 18, part 14, and die face 13 for providing access to those items and for permitting desired manipulations, inspection, etc. thereof. The second position 24A of the second end member 24 may conveniently be one in which gravitational forces tend furhter to rotate the end member 24 from its first, bridging position. The first lateral member 25 is preferably supplied with means for limiting to a desired range the pivotal travel of the second end member 24 from its bridging postion, and such means may take the form of aligned stops 58 which may be integral with or rigidly attached to the upper lateral member 25, and in the example are on the upper side of the latter near its outer end.

The second lateral member 26 must be so constructed that its outer end portion is engageab'le by the latch 29 mounted by the pin 30 on the lower end of the second end member 24, the pin 30 being keyed, splined, or otherwise attached in non-rotatable fashion to the latch 29 and, for convenience of operation of the latter, being provided with a short, accessible, manually movable lever 59 extending generally normal to the pin 30. The second end member 24 is preferably forked at its outer end, and in the example shown has a pair of prong 61A, 610 connected at some distance from their ends by a transverse reinforcing member 62 which supports a central prong 61B. A transversely extending latch pin or cross-piece 31 pierces and is rigidly mounted in the end portions of the prongs 61A, 61B, 61C Where it is readily engageable by a hook 64 of the latch 29 when the second end member 24 is placed in its first, bridging positon. The hook 64 has a central notch 65 to provide clearance for the central prong 61B.

Referring now to Figure 6, the ram of the example comprises a barrel 66, first and second end domes 67A, 67B, air piston 68, plunger 70 operated by the air piston 68, air control valve 38 with swivel fitting 39, hydraulic housing 73, hydraulic piston 35, resilient means comprising a spring 74, packings sealing around the plunger 76 between the barrel 66 and hydraulic housing 73, and a self-contained supply of hydraulic fluid 76 in the hydraulic housing 73 and in a cavity 77 formed in the hydraulic piston 35.

The barrel 66, which is cylindrical, has a smooth inner surface on which rides in airtight contact therewith the peripheral surface of the air piston 68, the latter being slideable substantially from end to end of the barrel. The piston 68, for reasons which will become apparent, has a substantially large central portion 78 shaped in the form of a cone whose apex is directed, as viewed in the drawing, toward the right-hand end of the barrel 66.

band 66 in order to make the barrel airtight around that end. The conical forms of the domes 67A, 673 have other advantages of structural strength, etc. which will beapparentto those skilled in the construction of pressure vessels, cylinders, and the like. The first dome 67A has.a central opening 79A in which is mounted the air control valve 38, and is provided with an inwardly extending cylindrical portion 80 which serves as a stop for the air piston 68.

' The air control valve 38 may be of any construction which will adequately'perform certain required functions, such valves being well known and commercially available. The valve 38 should allow rotation of the ram about its axis without imposing a corresponding rotation upon a valve-attached air hose 37, and should selectively direct air from the hose 37 to either end of the barrel 66 while connecting theother end to the atmosphere; The

' valve 38 shown has a case 82 rigidly mounted at one of its; ends in the central opening 79A of the first dome 67A and extending outwardly therefrom along the central axis of the ram. n the outer end of the valve 38 is a two-position operating handle 83 which may be actuated for connecting the air hose 37 through a first valve port 84 to the interior of the barrel 66 at the first dome 67A while connecting the other end of the barrel 66, through a line 86 and an exhaust port 85 in the valve handle 83, to the atmosphere. Repositioning of the handle 83 results intreversal of these connections. The valve case 82 receives air from the hose 37 through an annular swivel fitting 39 which is rotatably and encirclingly mounted on the valve case 82. While providing leak-proof communication between the hose 37 and the interior of the case, the swivel. fitting 39 may be held immobile by an operator or by the hose 37 while the ram, including the valve case 82, is rotated.

.The second dome 67B is pierced by a fitting 87 connecting the line 86 to the interior of the barrel 6, and has a relatively large central opening 7913 in which is mounted the hydraulic housing 73. The housing 73 has an externally threaded cylindrical portion 33, most of whichlies outside the dome 67B, and a generally conical portion 88 lying inside the dome 67B; A flange or collar.90 formed-around the cylindrical portion 33 lies against the inner surface of the end dome 67B, and a tap'ped nut 91 is run down on the external threads of cylindrical portion 33 into firm, airtight contact with the outer surface of the dome 67B, thus rigidly and sealingly attaching the housing 73 in the central opening 79B. The housing 73 has a generally cylindrical inner-end bore 69 provided with packings 75 through which the air piston plunger 70.(to be described) extends from the barrel 66. .For an axial interval extending beyond each side of the external shoulder 90, the housing 73 is provided with a second, larger, cylindrical bore 81 which is connected to the inner-end bore 69 by a conical surface 71.

81 to, the outer end of the housing 73." A cup-like member 89 whose inner diameter is identical with that of the second bore 81 is installed, with its open end in axially spaced relation to the second bore 81, in the outer-end bore 72 against packings 96 installed between the same and the outerend of the second bore 81. An

annular, externally'threaded retaining piece 92 engages A third, still' larger cylindrical bore 72, threaded at its outer end, extends from the second bore 8 whichis pierced byacentral opening 93 and, as desired; by lightening holes such as shown at 94. V-The exteriorly threaded cylindrical portion 33 of the housing'73 is en- 'g'ageable, as previously described, with a correspondingly threaded component of the mounting means;

The hydraulic piston 35 has a head 36 provided with a conical face which extends at a slightly less sharp angle to the axis ofthe housing 73 than does the. housings inner conical surface 71, which the piston closely ap? proaches when moved to the end of its range of 'travel toward the interior of the barrel 66. The piston 35 has an outer skirt 95 which, while fitting snugly and slideably in the second bore 81 and the inner diameter of the cup-like member 89; is sealingly encircled throughout all its stroke by the packings 96. The piston 35 has an integral rod 97 that extends'from the outer end of the housing 73, the rod 97 being encircled by a coil spring 74 which, compressed between the bottom of the cup 89 and the piston head 36, urges the piston 35 toward a retracted position within the housing 73. The piston head 36 and rod 97 are pierced by an axially aligned hole 77 which, while extending to a point near the'oute'r end of the rod 97, is of somewhat'larger diameter than is the plunger 70. This hole 77, together with the space between the piston head 36 and the inner conical surface 71 of the housing 73, defines a cavity containing the hydraulic fluid 76 utilized in the ram.

Rigidly connected at one of its ends to the air piston 68, the plunger 70 has a second end which extends, as described above, into the hydraulic'housing inner-end bore 69 when the air piston 68 is at the end of its range of motion toward the air valve 38, and, when the air piston 68 is moved toward the housing 73, extends into the cavity 77 of the hydraulic piston 35. j

Readily transportable, the ram 34 (Figure 1) 'may easily be moved' from one operation and location to another, and with the mount 22 may be used in association with any one of a Wide variety of stretch-forming dies such as 10. 'One or both of the

lateral members

25, 26 may be disconnected from the. inner member 41 by removal of one or both of the

pins

55A, 55B (Figure 3) to permit insertion of the inner member 41 and bushing 40 into the stretch forming die hole 21, following which the removed lateral member or

members

25, 26 are reconnected to the inner member 41. With the bushing shoulder 42 in contact with the die 10, the bushing 40 is rotated until the rams piston 35 (Figure 1) is in proper vertical adjustmentrelative to the die face 13 and joggle block 18. Lateral adjustment of the piston is accomplished by appropriate rotation of the inner member 41 and bushing 40 in the die hole 21. Gross adjustment of the interval betweenthe freeend of the ber

upper slots

49A, 49B (Figures 3, 4) and matching lower' slots (near-side slot 56B shown) to place the hydraulic piston 35 approximately in its desired position and to align

holes

53, 57 of the upper and lower lateral members with corresponding holes 54A or 54B (Figure 5) of the inner membenand re-inser-ting the pins 55A, 5513. Fine adjustment of the interval between the piston 35 and joggle block 18 is made by rotating the ram 34 about its own axis, thus causing the threadedcylindrical portion 33 (Figure l) to move in an axial direction in the threaded hole 32 of the second end member 24. During this rotation, the body of the valve 38 rotates in the swivel fitting 39, which, with the hose 37, remains immobile.

Prior to strecth forming and joggling a part, the latch lever 59 is pivoted to disengage the latch 29, and the ramt34 and second end member 24 are rotated, on the end member pivot pins 28, to a position, in which, as shown in Figure 3, the second end member 24 strikes against the stops 58 on't'ne upper side of the upper lat- 9 eral member 25. In this position 24A of the second end member, gravitational forces acting on the ram tend to continue rotation of the second end member along the are 60, and consequently hold the second end member 24 stable in its position 24A against the stops 58.

The part 14 to be stretch-formed and joggled is grasped in the

jaws

17A, 17B and the latter are moved to bring one side of the part 14 into contact with the die face 13. Elongating forces are then placed on the part by the jaws, which are moved for wrapping the part 14 against the die face 13 to produce in it a curvature corresponding to and determined by the curvature of the die face. Little, if any, joggling of the part will occur, however, at the joggle 16 in the die (Figure 2) during the stretch forming portion of the operation.

Preparatory to joggling of the part 14, the part is left in the

jaws

17A, 17B and the joggle block 18 is brought into place against the part 14 and in register with the die joggle 16. The arm 34 is moved to swing the second end member 24 back again along the arc 60 (Figure 3) and the latch 29 is engaged with the latch pin 31 on the lower lateral member 26 to bring the rams hydraulic piston 35 (Figure 1) into close, confronting relation with the joggle block 18.

Joggling of the part 14 is accomplished by positioning the valve handle 83 for causing extension of the hydraulic piston 35 against the joggle block 18 and for pushing the block 18, part 14, and die joggle 16 closely together to bring the part 14 into conformity with the complementary shapes of the die joggle 16 and joggle block 18. In many materials, this operation may introduce into the part a set which may tend to disturb its over-all curvature, previously introduced by the stretch forming portion of the operation, when the part is released from the

jaws

17A, 17B. This may be obviated in many cases by maintaining the previously imposed elongating forces on the part 14 during the joggling process, thus insuring proper yielding of the material of the part as it is brought into conformity with the die joggle 16 and joggle block 18. In other cases, maintaining all the stretching loads during joggling may overstress and crack or otherwise damage the part; in such cases, some of the elongating forces should be relaxed, butenough should be retained to insure proper forming, without subsequent excessive spring-back, of the desired joggle (Figure 2) in the part. After the joggle 15 is formed, the

jaws

17A, 17B are caused to relax the elongating forces from and release the part 14; the ram piston 35 is retracted by repositioning the valve handle 83; the latch 29 is released and the ram 34 is swung out of the way by moving the second end member to its position 24A (Figure 3); and the joggle block 18 and stretch formed and joggled part 14 are removed from the die face 13.

Since the part 14 is left exactly in place on the stretch die 10 after accomplishing the stretch forming operation, there is no possibility of the mislocation of the joggle 15 when the latter is introduced into the part, and time is saved which otherwise would be consumed in moving the part to another fixture for introducing the joggle.

Parts such as 14 frequently require the introduction along their length of a plurality of joggles such as 15. Since the pressure-exerting apparatus is small, light, and relatively inexpensive, more than one such apparatus may readily be combined with one stretch forming die such as 10 for the forming of a plurality of joggles in a given part.

When the valve handle 83 is moved to a first one of its two positions, which for example, may be the position shown in Figure 6, the valve 38 connects the compressed air hose 37 through the valve port 84 with the interior of the barrel 66 at the outer-end dome 67A, and connects the other end of the barrel with the atmosphere through the fitting 87, line 86, and exhaust port 85. The consequent air pressure differential across the air piston '68 drives the piston toward the hydraulic housing 73. and forces the plunger 70 through the packing into the housing 73 and on into the cavity 77 in the hydraulic piston 35, thus displacing hydraulic fluid from the cavity. This displacement raises the hydraulic pressure in the housing 73 sufiiciently to force the hydraulic piston 35 outward against pressure of the spring 74, and, when the piston encounters resistance, raises the pressure until the force exerted by the piston overcomes the resistance or until maximum hydraulic pressure is developed. Because of the angle included between the face of the piston head 36 and the inner conical surface 71 of the housing 73, all of the piston face immediately feels any increase in hydraulic pressure even when the piston 35 is fully retracted. The air piston 68 is stopped at the end of its stroke away from the air valve 38 when it strikes the small, inner end of the hydraulic housing conical portion 88. The plunger 70 is of such length that, when fully extended, it fails to bottom in the hydraulic piston cavity 77. A feature of the ram which permits compact construction thereof without limiting its operation here becomes apparent. The over-all length of the ram is reduced by enclosing muchof the length of the hydraulic housing 73 in the barrel. This is accomplished without shortening the stroke of the plunger 70, however, by viture of the generally conical form of the housing portion 88 lying inside the barrel 66 and by the corresponding conical form of the air piston 68, which, at the end of its stroke, nests over the housing portion 88.

As the area of the air piston is relatively large, air supplied through the hose 37 at a conservative pressure per square inch develops a considerable net force on the air piston, which force is transferred therefrom to the plunger 70. As the end area of [the plunger 70 is much smaller than that of the air piston 68, this force, transferred to the hydraulic fluid 76 by entry thereinto of the plunger, results in the development of a comparatively high hydraulic pressure when the hydraulic piston 35 meets resistance. The latter pressure acts on a comparatively large face area of the hydraulic piston 35, which face area includm the conical face of the piston head 36 and the surface defining the end of the cavity 77 near the outer end of the piston rod 97; consequently, thenet outwardly urging force on the hydraulic piston 35 is quite large and enables the ram easily to perform operations ordinarily achieveable only by much larger, heavier, and more complicated rams. Thus, to quote an example, where the air piston diameter is approximately 8 inches and the plunger diameter near 1.20 inches, the plunger displaces hydraulic fluid at approximately 4,273 p.s.i., and when the hydraulic piston area is 11.8 square inches, the output force exerted by the hydraulic piston is of the order of 50,378 pounds. Experience gained by the fabrication of a number of rams such as described indicates that the weight of a ram incorporating components of dimensions such as quoted above may readily be kept below 38 pounds without compromise of structural strength.

Moving the valve handle 83 to the second of its two positions reverses the above-described connections to the ram, and air pressure forces the air piston 68 away from the hydraulic housing 73 until it is stopped by contact with the first dome cylindrical portion 80. As the plunger 70 retracts from the housing 73, the spring 74 retracts the hydraulic piston 35 into the housing.

While only one embodiment of the invention has been shown in the accompanying drawings, it will be evident that various modifications are possible in the arrangement and construction of the pressure-exerting apparatus components without departing from the scope of the invention.

We claim:

1. Apparatus for forcing a. workpiece against a face carried by a body provided with a hole extending therethroughisatga'point removed from 'said face, an apparatus ofQsaidpbody; means for preventing axial motion of said first end, member relative to said body in at least one direction; said means being distinct from said workpiece;

first'and'second lateral members'distinct from said means for preventing axial motion of said first end member and extending beyond said facefrom said first end member, one of said lateral members having an inner end rigidly connected to one and the other of said lateral members having an inner end rigidly connected to the other-of said ends of; said jfirst end. member, at least one of said innerjendsof said lateral members being spaced from said body, said lateral members having respective outer ends spatially separated from each other and from said body; a second end member mounted on said outer end of said first lateral member and pivotable thereon to and from a positionwhereiri said second end member lies in bridgingrelation between said outer ends of said first and second; lateral members; latching means for releasably connecting said second end member to said second lateral member for locking said second end member in said bridging relation between'said outer ends of said first and; second lateral members; and a ram having an extensible member, said ram being mounted'on said second end member in a positionrwherein, when said second end member is locked by said locking means in said bridging relation betweensaid outer ends of said first and second lateral members, said extensible member of said ram' 7 member from said second lateral member and said second end member being pivotable away fiom said second lateralv member for. moving saidram away from said face of said bodyto a stable position.

3."T he apparatus claimed in claim -l, said apparatus further comprising means for axial adjustment of said first end member in said hole provided in said body, said axial adjustment of said first end member effecting intervallic. adjustment between said body and said inner ends of said first and second lateral members.

4. The apparatus claimed in claim 1, said apparatus comprising means for axial adjustment of said ram relative to said second end member for varying the distance between said extensible member of said ram and sai face carried by said body; a 5. Apparatus for'forcing a workpiece against a face carried by abody provided with a hole extending therethrough at a point removed from said face, an apparatus comprising, in combination with said body: a first end member extending through said hole and having first and second ends protruding from respective, opposite sides of said body; means for preventing axial motion of said first end member relative to said body in at least one direction, said means being distinct from said workpiece; first and second lateral members distinct from said means for preventing axial motion of said first end member and extending beyond said face from said first end member, one'of said lateral members having an inner end rigidly connected to one and the other of said lateral members having an inner end rigidly connected to the other of s'aidlends of said first end member, at least one of said inner ends of said lateral members being spaced from said body, said lateral members having respective outer ends spatially separated from each other and from said body; a second end member mounted on said outer end of said first lateral member md pivotable thereon to a positrbnwh'er'ein saidsecond end member flies in bridging relation between said'outerends of said first and second lateralmembers, said'second end member having a threaded opening; latching means for releasably connecting said second end member to said second lateral member for locking and unlocking said secondend member in said bridging relation between said outer ends of said first and second lateral members, said latching means being operable for disconnecting said second end member from said second lateral member; and a ram having an extensible member and a cylinder provided with peripheral threads, said ram being mounted in said opening of said second end member by engagementof said peripheral threads with threads of said opening, saidram being axially adjustable relative to said second and member by rotation of said cylinder in said threaded opening, said. extensible member of said ram lying in opposite, facing relationship with said face carriedby said body when said second end memberis locked by said latching means in said bridging relation between said outer ends of-said lateral members, and said second end member being pivotable, when said latching means is operated for disconnecting said secondend member from said second lateral member, to a stable position wherein said extensible member is spaced from its position of opposite, facing relationship with said face carried by said body.

6. The apparatus claimed in claim 5, said means for preventing axial motion, in at least one direction, of said first end member comprising a cylindrical bushing provided withinternal threads, ,a smooth outer surface snugly and rotatably received in said hole provided in said body, and an'external collar engaging an outer surface of said body; and said first end member comprising an inner cylindrical member provided with external threads rotatably insertable insaid bushing by engagement with said threads of said bushing, said bushing being rotatable about said inner member for effecting axial adjustment of the latter in said bushing.

- 7. Apparatus for forcing a workpiece against a face carried by a body provided with a hole extending therethrough at a point removed from said face, an apparatus comprising, in combination with said body: a cylindrical bushing provided with internal threads, a smooth outer surface snugly and rotatably received in said hole provided in said body, and an external collar engaging an outer surface of said body; an inner cylindrical member provided with external threads engaging said threads of said bushing, said inner member being rotatably insertable through said bushing and having first and second ends protruding from respective, opposite sides of said body, said bushing being rotatable about said inner member for effecting axial displacement of the latter in said vbushing; first.and second lateral members extending beyond said face from said first end member, one of said lateral members having an inner end connected to one and the other of said lateral members having an inner end connected to the other of said ends of said inner cylindrical. member, said lateral members having respective outer ends spatially separated from each other and from said body; a stop mounted on said first lateral member in the region of said outwardlyextending end thereof; a cross-piece rigidly mounted on said second lateral member the region of said outwardly extending end thereof; an end member pivotally mounted on said outer end of said first lateral member and pivotable thereon to a position wherein said end member lies in bridging relation between said outer ends of said first and second lateral members, said end member beingpierced by a hole provided with threads; a latch ,movably mounted on said end member and engageable'with, said cross-piece forrigidly locking said end member in bridging relation with said first and second lateral members; and a ram having a cylindrical surface provided with external-threads rotatably engaged with saidthreads of said hole'piercingsaid end member,

said ram being rotatable in said hole in said end member for axial adjustment thereof relative to said end member, said ram being provided with an extensible member and having a swivel fitting for the connection of said ram to an air line, said extensible member of said ram lying in opposite, facing relationship with said face carried by said body when said latch is engaged with said cross-piece, and said end member being pivotable to a stable position against said stop wherein said ram is spaced from its position of opposite, facing relationship with said face carried by said body.

8. Apparatus for forcing a workpiece against a face carried by a body provided with a hole extending therethrough at a point removed from said face, an apparatus comprising, in combination with said body: a cylindrical bushing provided with internal threads, a smooth outer surface snugly and rotatably received in said hole provided in said body, and an external collar engaging an outer surface of said body; an elongated member of circular cross-section having external threads rotatably engaging said internal threads of said bushing, said elongated member further having a first axis and first and second ends, each of said ends having, at a point outside said body and said bushing, a cavity extending along a second axis lying generally normal to said first axis, each of said ends further having a hole extending along a third axis generally normal to said first and second axm and opem'ng into said cavity, said hole in said first end of said elongated member being substantially parallel with said hole in said second end of said elongated member; first and second lateral members extending beyond said face from said first end member, said lateral members having respective outer ends spaced from each other and from said body and further having respective inner ends received in respective ones of said cavities of said first and second ends of said elongated member, each one of said lateral members being provided along its length with a series of transverse holes, each of said transverse holes being parallel with said third axis and alignable with a respective one of said holes opening into said cavities receiving said lateral members; a stop rigidly mounted on said first lateral member in the region of said outer end thereof; a cross-piece rigidly mounted on said second lateral member in the region of said outer end thereof; an end member pivotally mounted on said outer end of said first lateral member and pivotable to a position wherein said end member lies in bridging relation to said first and second lateral members at said outer ends thereof, said end member being pierced by a hole provided with threads; a latch pivotally mounted on an end of said end member and engageable with said cross-piece for rigidly locking said end member in said bridging relation between said first and second lateral members; a first pin insentable in said hole provided in said first end of said elongated member and into a one of said transverse holes of said first lateral member aligned therewith; a second pin insentable in said hole provided in said second end of said elongated member and into a one of said transverse holes of said second lateral member aligned therewith; and a pneumatic-hydraulic ram having a cylindrical surface provided with external threads rotatably engaged with said threads of said hole piercing said end member, said ram being rotatable in said hole in said end member for axial adjustment thereof relative to said end member, said ram having an extensible member and being provided with a swivel fitting for the connection thereto of an air line, said extensible member of said ram being brought into opposite, facing relationship with said face carried by said body when said latch is engaged with said cross-piece, and said end member being pivotable to a stable position against said stop wherein said extensible member of said ram is axially and laterally removed from its position of opposite, facing relationship with said face carried by said body.

9. An apparatus for producing stretch-formed, joggled parts comprising: a die having a face with a transverse curvature corresponding to the formed curvature of a part to be stretch-formed thereon, said face further having a joggle interrupting said curvature and corresponding to a joggle to be introduced into said stretchformed part, said die still further having a hole extending therethrough at a point spaced from said face; gripping means for gripping said part in areas spaced beyond said face of said die; a joggle block having a forming face positionable in facing relationship with said joggle in said face of said die when said part is disposed between said die face and said joggle block, said joggle block further having a back face disposed opposite said forming face thereof; a first end member extending through said hole in said die and having first and second ends protruding from respective, opposite sides of said die; first and second lateral members having respective outwardly extending ends spatially separated from said die and inwardly extending ends respectively rigidly connected to opposite ends of said first end member; a second end member provided at one of its ends with latching means and at its other end mounted on said outwardly extending end of said first lateral member and pivotal thereon to a position wherein said latching means is engageable with said outwardly extending end of said second lateral member for locking said second end member in bridging relation between said first and second lateral members; and a relatively small, light-weight ram mounted on said second end member in a position wherein, when said latching means of said second end member engages said outwardly extending end of said second lateral member, the output of said ram confronts said back face of said joggle block and energization of said ram may effect the application thereby of pressure against said joggle block.

10. The apparatus claimed in claim 9, said second end member being pivotable, when said latch is not engaged with said second lateral member, for moving said ram along an arcuate path away from said joggle block and to a stable position.

11. The apparatus claimed in claim 10, said apparatus further including means for adjusting said first end member axially of said hole in said die and means for effecting axial adjustment of said ram relative to said second end member.

12. The apparatus claimed in claim 10, said apparatus further including means for adjusting said first end member axially of said hole in said die, means for axial adjustment of said ram relative to said second end member, and means for connecting said first and second lateral members at a plurality of points along their lengths to said first end member.

References Cited in the file of this patent UNITED STATES PATENTS 369,166 Daniels Aug. 30, 1887 836,630 Caskey Nov. 20, 1906 1,688,199 Meier Oct. 16, 1928 1,781,592 Meier Nov. 11, 1930 2,148,619 Hanschild Feb. 28, 1939 2,446,089 Hochreiter July 27, 1948 2,548,784 Hansen Apr. 10, 1951 2,619,149 Self Nov. 25, 1952 FOREIGN PATENTS 494,702 Germany Mar. 27, 1930 711,196 Great Britain June 23, 1954 734,647 Germany Dec. 5, 1939