US2923342A - Elongated channel draw bench for sheet shaping machine operating on the forming-by-drawing principle and having lubricating means for a carriage slidable in said draw bench - Google Patents

Description

F. ANDERSON Feb. 2, 1960 E m HD 0N AHA E GLE NFC I IA PCT ANR um PC T 1 .AE %w B WWW AF RR R 080 F N mm '1 m MA N S ENG BTNN mfl WOAE RFCL D IB ER HBD ETUT N L... n vG m m I @TH TA AR CE P W0 m.

11 Sheets-Sheet 1 Original Filed Feb. 8, 1955 Feb 2, 1960 2,923,342 CHINE AND F. ANDERSON RAW ELONGATED CHANNEL D BENCH FOR SHEET SHAPING MA OPERATING ON THE FORMING-BY-DRAWING PRINCIPLE HAVING LUBRICATING MEANS FOR A CARRIAGE SLIDABLE IN SAID DRAW BENCH 6b. 8, 1955 l]. Sheeta-5heet 3 Original Filed F F. ANDERSON Feb. 2, 1960 I 2,923,342 BENCH FOR SHEET SHAPING MACHINE OPERATING ON THE FORMING-BY-DRAWING PRINCIPL AND FOR A CARRIAGE AW BENCH ELONGATED CHANNEL DRAW HAVING LUBRICATING MEANS SLIDABLE IN SAID DR Original Filed Feb. 8, 1955 11 Sheets-Sheet 4 W m M M M W m 1960 F. ANDERSON 2,923,342

ELONGATED CHANNEL DRAW BENCH FOR SHEET SHAPING MACHINE OPERATING on THE FORMING-BY-DRAWING PRINCIPLE AND HAVING LUBRICATING MEANS FOR A CARRIAGE SLIDABLE m SAID DRAW BENCH Original Filed Fab. 8, 1955 A 11 Sheets-Sheet 5 2 4 h a .K- lldll 5 4 b 4 4 5 w 3 2 3 h 3 96 mvflwwgw WT. Tm Z IIIJW 2 H ,IIIL |1|I H111 \\v\ A .H.. r| 4+ 1 QT- M6 N1 5 I I N 4 px M a .724 a K. I. 1 9 & 0 9/ mu $90 6 a w w 4 4 6533 333666 6 lV l/ /N 1/5 7019 FIFO/{MAN A/vofkjalv BY M A TTOR/VEY Feb. 2, 1960 F. ERSON 2,923,342

AND ELONGATED CHANNEL DRAW BENCH FOR SHEET SHAPING MACHINE OPERATING ON THE FORMING-BY-DRAWING PRINCIPLE AND HAVING LUBRICATING MEANSFOR A CARRIAGE SLIDABLE IN SAID DRAW BENCH Original Filed Feb. 8, 1955 ll Sheets-Sheet 6 ma 9 /3 7g A77'0/P/VEY Feb. 2, 1960 F. ANDERSON 2,923,342

ELONGATED CHANNEL DRAW BENCH FOR SHEET SHAPING MACHINE OPERATING on THE FORMING-BY-DRAWING PRINCIPLE AND HAVING LUBRICATING MEANS FOR A CARRIAGE SLIDABLE IN SAID DRAWBENCH Original Filed Feb. 8, 1955 11 Sheets-Sheet T FRO/ IVAN ANDERSON 92 99 89 93 m4 M4 95 00 036 v 89 T T I I l I E /-v/vroR I L :1

ATTORNEY Feb. 2, 1960 F. ANDERSON 2,923,342

ELONGATED CHANNEL DRAW BENCH FOR SHEET SHAPING MACHINE OPERATING ON THE FORMINGBY-DRAWING PRINCIPLE AND HAVING LUBRICATING MEANS FOR A CARRIAGE" SLIDABLE IN SAID DRAW BENCH Original Filed Feb. 8, 1955 ll Sheets-Sheet 8 l I 1 I L I l l I l I s F- ANDERSON ENCH FOR SHEET SHAPING MING Feb. 2, 1960 2,923,342 MACHINE E AND ELONGATED CHANNEL-.- 0

RAW B OPERATING ON THE FOR BY-DRAWING PRINCIPL HAVING LUBRICATING MEANS FOR A CARRIAGE SLIDABLE IN SAID DRAW BENCH Ongmal Flled Feb 8, 1955 ll Sheets-Sheet 9 3mm 5% 8mm IIIIII.+I+ II I I I N I II I W I I W III M I .Jl I IANI Ii .1 mg L N? L. I I I II I I IFI I I I V I I FH I I I I I I% I Q. MY Nm mvm M 6mm III tIII M IIIIII I 1. I I IUIMI I I H. V I I I I H I MI H I H I H I H I E F. ANDERSON RAW BENCH FOR SHEET Feb. 2, 1960 2,923,342 SHAPING MACHINE ELgggATED CHANNEL D RATING ON THE FORMING-BY-DRAWING PRINCIPLE AND nAvmc l gglz r ggw gc mmus FOR A CARRIAGE AI D Original Filed Feb. 8, 1955 D RAW BENCH 1'1 Sheets-Sheet i0 h H n n h. n c n n H w P 5 5 =W H H H :H N w NN wbmfi H. m m .CR HHM.13cm.wmwwww m w m H w ?c. n flm C g \E E Q .e H mc fluw H E A091. A IIIIY m mm mm Feb. 2, 1960 ANDERSO OPERATING ON THE MI WING PRINCIPLE AND HAVING LUBRI ING MEAN OR A C IAGE IN SAI SLIDABLE D DRAW BENC Original Filed Feb. 8, .1955 ll Sheets-Sheet 11 m5 ifi g ATTORNEY F. N 2,923,342 ELONGATED CHANNEL DRAW BENCH FOR SHEET SHAPING MACHINE NG BY- United St Patent O ELONGATED CHANNEL DRAW BENCH FOR SHEET SHAPING MACHINE OPERATING ON THE FORMING-BY-DRAWING PRINCIPLE AND HAVING LUBRICATING MEANS FOR A CARRIAGE SLIDABLE IN SAID DRAW BENCH Frohman Anderson, Las Vegas, Nev.

Original application February 8, 1955, Serial No. 436,77 3, now Patent No. 2,851,080, dated September 9, 1958. Divided and this application November 1, 1957, Serial No. 693,932

7 Claims. (Cl. 15332) This application is a division of application Serial No. 486,773, filed February 8, 1955, now Patent No. 2,851,- 080, which relates to a machine for shaping metal sheets into compound curves by pulling the sheets edgewise from one end to the other over a series of forming elements the Working faces of which differ in contour transversely of the sheets and are disposed in stepped relation, a restraining or hold-back force being exerted on the sheets in opposition to the pulling force to subject the sheets to stresses beyond their yield point. This operation in the said parent application is termed forming-by-drawing.

Such machines are composed of three main functional components comprising the sheet forming structure, a draw bench including a power actuated carriage for the mechanism that is to be translated in the performance of the operation, and the sheet pulling mechanism attached to and propelled by the carriage for gripping and pulling the sheets through the forming structure.

This application relates to the draw bench construction. More specifically, it relates to the draw bench and its relation to the forming structure including the means for lubricating the draw bench slide or carriage.

One of the main functions of the carriage is to translate the jaws to pull the sheets through the forming elements and, being thus heavily loaded, it presents a problem of proper guidance and lubrication. Power means of considerable proportions are required and therefore suitable disposition of the draw bench with respect to the forming structure presents a problem.

In accordance with this invention, the work bench is supported upon the gear box or housing for the gearing, its ends being supported by legs. The gear box is supported upon the base to which are attached the uprights for the forming structure, being either directly in line with the forming elements so that the jaws are carried over the bench, or at one side thereof in close proximity so that the jaws are carried by a laterally extending head,

The bench is U-shaped in cross section and serves as a guide for a carriage sliding therein. A rack on the bottom of the carriage is engaged by a bull gear in the gear box and is thus propelled. Because of the great stress to which the carriage is subjected by the up thrust of the feed gear and the pulling strain, the sides of the guide are provided with an overhang which also requires lubrication.

In accordance with the invention, that bench is provided with a pair of vertical oil ducts that communicate withan oil pressure source and lead to the under side of the carriage on opposite sides of the guide channel and through a branch to the underside of each overhang, thereby providing lubrication for the top and bottom surfaces of the carriage near each side edge, these surface portions bing preferably provided with wear plates.

To distribute the oil on the under side of the bottom wear plates, a longitudinal groove is formed in the lower surface of each bottom wear plate which is continuous from end to end of the plates and is disposed in register with the respective vertical duct.

Also to lubricate the side edges of the carriage, these edges for a distance at each end are provided with wear plates and one or more right angle passages in the slide provide communication from the respective continuous longitudinal groove on the bottom face of the carriage to the side face where the face of the wear plate is recessed laterally for effective oil retention and distribution. The longitudinal groove .is also provided at intervals with a lateral recess for effective distribution of the oil on the under surface of the carriage.

Since thestress to which the carriage is subjected, due to the up thrust of the bull gear and the pulling stress, is concentrated on the portion of the draw bench onthe gear box' and at the delivery end, there is no need for an overhang on the feed end of the bench, and, therefore, for economy, the overhang is discontinued from the gear box to the feed end of the bench; The oil duct in the overhang also feeds into a longitudinal groove on the top face of the top wear plate on each side, but since the portion of the groove outside the overhang is uncovered, it is obvious that the exposed portion cannot be connected to pressure. For this reason, the groove in each of the two top wear plates is interrupted at points such that the uncovered portions of the grooves in the retracted position of the carriage are not connected to the groove sections which are under pressure.

The length of the draw bench and carriage must,of course, be suited to the length of the sheets to be drawn and in order that the carriage may have the capacity for operating on long sheets without the necessity for the excessive travel when operating on short sheets, the'invention contemplates means to vary the length of the bench and carriage to adapt them to the particular length of sheets being formed.

The invention has other objects and advantages as will appear from the following description of the embodiment ofthe invention illustrated in the accompanying drawings. 1

Fig. 1 is a side elevation of a machine embodying the invention,

Fig. 2 is a plan of the same.

Fig. 3 is a front elevation of the forming structure and a partial transverse section of the draw bench on the line 33 of Fig. 1. t

Fig. 4 is a partial sectional view of the forming struc-' ture and of a portion of the draw bench structure on line 44 of Figs. 1 and 6.

Fig. 5 is a fragmentary detail on thesection line 5--5 of Fig. 4.

Fig. 6 is a vertical section of the machine on a plane central of the forming structure on line 6--6 of Figs. 3 and 4.

Fig. 7 is a plan of the gear box and enclosed mechanism on line 77 of Figs. 1 and 8.

Fig. 8 is a vertical section on line 8-8 of Fig. 7.

Fig. 9 is a vertical section on line 99 of Fig. 7.

Fig. 10 is a partial elevation and partial section on line 1010 of Fig. 8.

Fig. 11 is a fragmentary plan of a section of the draw bench with extension added, being generally as viewed on line 1111 of Fig. 12. r

Fig. 12 is a longitudinal section on broken section line 1212 of Fig. 11.

Figs. 13 and 13a are fragmentary plans of the carriage vary their-spacing in the direction of draw. means for this purpose are attached to the rearwardly slide and draw:bench,i:Fig. .13 being of the 'forward end,

" of th'e draw bench and slide,-the section "being on line f 15-'--1'S of Fig. 13.

Fig. 16is a fragmentary horizontal "section on line 16-16 of Fig. 15 and on a reduced scale.

"In :theillustrated construction; the-draw bench is disposed alongside the forming structure; 'all'being supported upon a common base. The forming structure comprises three stages, which in the-embodiment shown are con' "gained between two uprights :attachedto the common 'ase.

"The" first stage of the forming structure. has.;a lower "'T-shapedfbody member withthecross :headxextending between the uprights and-carryingja forming and holdback element which presents a straight edge over which the sheer-is drawn and so determines 'the general path -of movement of the sheet. An-upper vertically sli'dable ranrmember opposes the cross head and'cooperates' with the lower element to impose a regulatable' pressure upon the sheet, being --verticallyadjustable and guided 'within the uprights. The first stageis, therefore, known as the hold-backstage.

The second stage comprises -a ram 'member spanning -the:uprights--and guided therein for vertical adjustment, Afor'ming element carried by'the ram member has a geometrical contour differing from that of the hold-back element of the first-stage and in operation is in stepped relation to the first-stage element. It constitutes a drawover' forming element.

The third 'stage also has a T-shaped body member with the cross head spanning the uprights. A forming element carried by the'cross head is of a contour complernentary to that of the second stage element. That "is, if one is convex the-other is of a corresponding concaveshape. The third stage forming element is disposed beyond the' second stageelement in the direction of draw and in stepped relation-thereto during operation so that the sheet takes a reverse bend in its draw over the third stage element, and engages-the third stage elementwith the side opposite that withwhich it engages the secondstage-element. 'The function of this third :stageis 'to compensate for the surface extension resulting from the draw over the second stage and-thus con- .trolthe coiling tendencies of the sheet.

Means are provided to adjust the first and third-stages forward and back relative'to thesecond stage so as to Power extending legs of the T-shaped members. Means are *alsoprovided totilt the first stage about a central longitudinal'axis-and to raise and lower'the first stage as a unit about a transverse axis. These-relative movements 'oil the' first and third stage elements have important functional efiects on the drawing operation, as is fully explained in the said-parent application.

A base structure '10 hasat one'side a gear box 11 supported thereon, and laterally of the gear box two spaced uprights 12and 13 are attached to and supported by the base. The gear box 11 abuts and is attached by keys-to upright 13.

Thefirst stage structureis' shown in Figs. 4 and 6.

It has twosecondaryuprights*-14and-:i15 which contain both the lower T-shaped member and-the upper ram fassembly so'that thesemay be'moved together-as a =unit relative'to the uprights 12 and-13, having guiding connection therewith through rocker bearing plates 16 The upper first stage assembly comprises a top' fixed I bar 18 which spans the secondary uprights and is adjustable in height between .gibs 19 .on the uprights, a ram 20 which is also a cross bar spanning the uprights and slides within gibs 21, and toggles 22 and 23 connected by bar 24. A hydraulic cylidner 25 has trunnions in bearing brackets 26 on ttop of fixed bar 18, with its piston rod connected to the top end of a toggle operating lever 27 that has its fulcrum pivot in bar 18 and is pivoted at its lower end to the pivot of bar 24. The lever 27 is double, the rear arm being-slightly -wider1than the front as-indicated;in FigLZ'and by broken lines in 'Fig. 4. The bar 18 is hollow, as shown.

It is desirable to adjust .the he'ight of the bar 18 for sheets of different thickness and, as shown in Figs. 4 and 5, the ends ofthebar 18 are notchedand the gibs 19 are notched. Blocks.28 are inserted,in ,thevrregistering notches and shims on top of .theblock. determinethe upward limit of movement ,of bar :18. :The adjustment of the bar 18 is effected by screws 29 whichLscrew-through bridge pieces on ,top of the .gibs and into tapped holes in the bar.

A hold-back ielement 3 0.;has .a dove tail connection with. the bottom faceofram 20. and,is clamped in place by clamp strip '31. ,SmQQthingplatefiZis disposed immediately back of hold back element 30.

The lower first stage assembly Icomprises a T-shaped body member .33'havingla cross headf34 which spans thesecondary uprights I l-and I5 and a rearwardly extending leg member 35. Ahold-back element 36 has a dove tail connection with the top face of cross head 34 and is clamped in placeby'clamp strip 37; The hold-back element 36.1opposes the upper hold-back element 30 andis of complementary shape. The sheet S is fed between the two elements 30 'and'36 and between the smoothing plate 32 and an opposing-smooting plate 38 on thelower first stage .body member 33 immediately back of the. lower hold-back element'36.

Thefirst stage assemblyis dynamicallyxadjustable for- Wardly and' backward to alimited extent to and from the second stage. Thisis donethrough a hydraulic cylinder 39, which, as shown in'Fig'Z, hasitsjpiston rod connected througha pivoted coupler 40 and links 4110 a wrist pin 42 in the end of theleg member 35. The first stage structure is also dynarnicallytilted-about a longitudinal axis and. raised and ,lowered about a transverse axis by hydraulic cylinders 43. For this purpose, the T-shapedbody member33ofthe' lower first Stageas sembly issupported on thebase 'through a guide structure '44 which is "mounted for; 1universalmovement througha gimbal mount "45. Thisguide structure has two forwardlyextendingarms lla to which the pistons of cylinders43 are-attached. *Th'e rearwardl-y extending leg '35 0f meniber33isguidedin the guide-structure 44 in its dynamic adjustment -to and from tlre second stage.

The second-stage assembly, asshown in Figs. 3 and 6,

has at the top "a fixed bar 46 spanning-and attached at its ends to theuprights 12 and' 13; *Supported by this bar through *toggles is a-two part=ram which carries the second stage forming'element and is raised and lowered by means of the toggles which are operatedby ahydraulic'cylinder' and piston; Thetwo parts'of the ram have turn-buckle connection'providing for adjustment of the relative horizontal disposition of the two parts of the ram.

The two parts-of the ram are upper bar 47 and lower elementcarrying bar 48 which are connected-by--turnbuckles 49. Toggles 50 connect thefixed bar 46 and bar 47 of the ram, the toggle joints being connected by bar 51. "The toggles are operated-by hydraulic cylinder 52" supported on brackets 53 on-upright 13. The piston of the cylinder is connected to the end of toggle-operating bar51 bypiston rod 54.

A counterweightSSfon the ram is loaded on the free endoflever 56 which is-pivoted at its other end to the top edge of fixed bar 46 and has an extension beyond the t S ivot connected to the top edge of bar 47 through links 57.

The ends of the ram bars 47 and 48 are constrained and guided by rails 58 which are fastened on the uprights and enter into the slotted ends of the ram bars.

The lower edge portion of the ram bar 48 is thinner than the main portion of the bar and a forming element 59 is fastened to its inner face, having a dovetail connection therewith and being secured in place by a wedge member 60 hearing on its top edge and secured in place by screws 60a. The forming element is a full length plate extending from end to end of the ram and having a forming surface on its bottom edge which in the illustrated setting is downwardly curved. The work-engaging portion is a ridge at the entrance or inner side portion of the bottom edge, beyond or in front of which the bottom edge is raised and is opposed by the complementary shape work-engaging face of the third stage element, as will be seen.

The T-shaped body member of the third stage has a carrier T-shaped structure consisting of a cross head 61 and a rearwardly extending leg 62, being supported and guided upon the super base structure 63. On the cross head 61 is the cross head 64 to the rear face of which the third stage forming element 65 is attached by a dovetail connection, and locked in place by a wedge 66. This third stage forming element is a full length plate, the upper edge of which has a longitudinal concave curvature substantially complementary of the second stage element, having as its work-engaging portion a raised ridge at its front or exit edge which opposes the raised portion of the second stage element beyond its work-engaging ridge portion.

The third stage body member, like the first stage member, is susceptible of forward and back dynamic movement during the drawing operation. For this purpose, the rearwardly extending leg 62 has connection with a hydraulic cylinder 67 which is disposed in the super base structure as shown in Fig. 6. A cross head 68 is connected to the rear end of leg 62 and to horizontally reciprocating piston rod 69 of cylinder 67, the cross head having depending legs 70 which have feet that are guided under cleats on base 10 (see Fig. 3).

The gearing in the gear box 11 is driven by the main power unit M1 through the gear reduction in housing 71 and the coupling 72 (Fig. 2). The coupling engages and drives shaft 73 (Figs/7 and 8) which drives pinion 74. Shaft 73 is hollow and contains an internal pump shaft extension 75 which bears in the bearing 76 on an L-shaped base strip 77 resting upon the top edges of two cross members 78 and 79, the other bearing for shaft 73 being in the wall of the gear box. The member 79 serves as across brace and extends diagonally, as shown, for clearance purposes and has openings along-its bottom edge to provide free communication between the two sides of the member. The entire bottom of the gear box up to the member 78 constitutes an oil-collecting sump for returned lubricating oil, as willbe described, 'and the member 78 serves to partition off a space 80 which is a tank for clean lubricating oil, filters 81 in the collecting sump delivering into the tank 80. The top 8011 for the tank 80 has a removable cover 82.

The pump shaft 75 operates a pump 83 through an eccentric on the shaft and draws clean oil from the tank 80 through connection 84 and delivers it into a line 85 from which it is distributed to several points, as will appear. v

The pinion 74 meshes with gear 86-the shaft of which bears in hearings in the two sides of the gear box and has pinion 87 fixed thereon. Pinion 87 meshes with bull gear88 the shaft of which bears in bearings in the sides of gear box 11. The hull gear meshes with and drives a rack on the carriage as will now be described.

The top of the gear box is machined to form a seat for the fixed draw bench 89 which'guidesthe carriage,

6 the seating of the draw bench: upon the gear box being shown in Figs. 9 and 10.

The draw bench is an elongated channel guide member which rests at substantially its mid-point on the gear box and has its extending ends supported at intervals by legs 90. The cross-sectional shape of the draw bench is shown in Figs. 9 and 10. The upstanding sides of the channel serve as side guides for the carriage and for a portion of its length the upper edges of the sides have inwardly' overhanging projections 89a. These overhangs extend from the left end of the draw bench as viewed in Fig. 1 to somewhat beyond the middle of the gear box, as shown in Figs. 2 and 13, and serve to oppose the upward thrust of the bull bear on the carriage. They also have a function in the lubrication of the carriage, as will appear.

The bottom of the draw bench is provided with a longitudinal depression or channel as appears in the cross-sectional views, for accommodation of the rack on the bottom of the carriage, and immediately over the bull gear the bottom of the bench is apertured to provide for the meshing of the bull gear with the rack, as shown in Fig. 8. Also a removable cover 91 affords access to the interior of the gear box.

The carriage is a longitudinal sliding member 92 of a width fitting between the upright sides of the draw bench and, as will be seen, it carries the draw mechanism as well as other parts which require translation in the functioning of the machine. On its underside for the portion of its length corresponding to the length of its travel, the carriage has a rack 93 secured thereto which occupies the longitudinal channel or recess in the bottom of the draw bench. This rack is engaged by the bull gear.

The draw bench and carriage structure is shown in more detail in Figs. 13 to 16. The carriage is provided with wear plates, for example, formica, but preferably more durable material, such as bronze, where the greatest wear friction occurs. Since the draw mechanism, in the construction shown, extends laterally from the carriage, the drawing stress is lateral of the carriage and therefore imposes a lateral strain or torque upon the carriage and causes the greatest wear at two opposing side terminal portions. At these portions, therefore, the wear plates should be metal while formica will sufiice for'the other bearing or wear strips.

.As shown in Figs. 13 through 14a, the carriage 92 has relatively long bronze wear strips 94 and 95 on opposite side ends and short formica strips 96 and 97 on the other opposite side terminals. It is evident that the drawing stress will cause a clockwise twisting force on the carrilage and produce the greatest friction on the bronze p ates.

Also the carriage has full length top and bottom formica wear strips on each face. The two top strips are numbered 98 and 99 and the bottom strips are numbered 100 and 101. The top strips 98 and 99 are rela tively narrow, their inner edges terminating with the overhang 89a, and the bottom strips 100 and 101 are of a width to reach to the channel in the bottom of the draw bench.

The top and bottom face wear strips are provided with lubricating channels or grooves, and lubricating oil is pumped into these from the gear box as will be described.

The forward wall of the gear box has in its upper portion two vertical oil passages 102 and 103 which are spaced to register with passages 102a and 103a, respectively, in the draw bench extending through to the slide space. The pump 83 delivers oil from tank to the bearings in the box and to the passages 102 and 103. Conduit has a branch 85a which delivers oil to the bearing 76 and to the other bearings for shaft 73, and it also delivers to the bearings for the shafts of pinion 87 and bull gear 88. Thence, it continues on and has branch outlets connected with the passages 102 and'103.

The formica strips 100 and 101 on the bottom of the carriage have full length oil grooves 100a and 101a together with several ,Iateral grooves and the top formica strips have interrupted oil .gr ooves .98a and 99a.

The passages 102a and 103a lead to the full length grooves 100a .and 101a on the under side ot wear strips '100 and 101, and branching from each of passages 102a and 103a is a-passage 194 leading up,;through therespective side wall ,of the .drawbench andinward and downward through the overhead portion 89a into the top grooves 98a and 99a. Vertic alpassages and 10% lead up from the respective grooves 100a and 101a into the carriage slide 92 and'branch laterally into recesses 105 in wear plates 94, 95, 96 and97 by way of lateral passages 106. There are .four passages102b and .1031; for the bronze wearplates v9.5 and .94,.respectively, and two passages 1021) and .1031) for theformica- wear plates 96 and 97, respectively. It will .be seen that thelength of each section of the interrupted grooves98g and 99a is such that the grooveis entirely ,coveredby .the overhang 89a when oil is delivered to it by the passage v104.

The excess lubricating oil delivered to the carriage through the passages abovedescribed runs-down into the channel for the rack and collects in a space around a rectangular angle member .107 surrounding the aperture for the bull gear in the bottom of the draw bench, and from thence it runs through a hole shown in Fig. 7 into a gutter 108 and is led to a tube 109 anddelivered into the oil sump in the bottom of the gear case. The oil level .ismaintained in the gear case about at the top of brace 79 and of the tank 80, so that thegear 86 and bull gear 88 run in it, as shown in Fig. 8.

The'length of the carriage and rack is adjusted to the maximum length of sheets to be drawn-and the draw bench is provided with bumpers 110 (see Fig. 1361) at its ends to limit the movement of the carriage in case the automatic means for stopping the motor fails, the length of the rack being such that the teeth leave the bull gear just before the bumpers are engaged.

It is desirable on occasions to extend the draw bench and carriage to formunusually long sheets, for example. One of the advantages of the draw bench construction above described is that it may readily be extended.

Figs. 11 and 12 illustrate means forsuch extension. The draw bench 89 has secured underneathit ,on each side of the rack channel aplate 111 by means of screws 112 and these plates have extensionsto connect to the draw bench extension 89Ex. The plate extensions have elongated screw holes through which pass screws 112a and screw into the bottom of the draw bench extension 89Ex. Extending from the end of each plate 111 is a threaded tie rod 113 which extends through a leg 99 or other downward lug on the draw bench extension and has a nut and washer on its threaded end which, when tightened up, .bears against the leg and draws the two sections of the draw bench together. A gasket 114 will be provided at the point, as shown, to prevent. leakage of lubricating oil.

A way is also shown to join an extension 92Ex to the carriage 92. As shown two screws protrude from the ends of each section disposed so as to aline, and those in one section have right hand threads and those in the other section have left hand threads. A nut on each pair completes turnbuckles 115. Thus, the two sections are drawn together and a key 116 is provided at the joint to aline and support the two edges vertically.

It will be understood that for a given extension'of .the carriage and rack the draw bench must have an equal extension on eachend.

Fig. 12 shows a super structure carried .by thecarriage which is not related to thepresent invention. As shown this super structure'is attached tothecarriage by a support 117. Fig. 12 illustrates how this super structure may be extended to compensatefor an extension of the carriage.

As stated above, the sheet pulling or drawing mechanism is carried and translated 'by the carriage. 'In'the illustrated construction, this consists of a laterally .extending arm 118, and a draw head 119 carried by the arm. The headfhas 'jawsfor gripping the'leadingedge of the sheet being drawn. vA'leg 12 0 supports the outer end of theiarm.

It is obvious that the particular construction of the draw bench and associated mechanism as shown in the drawings and above particularly described may be modified within the scope of the invention as defined in the following claims.

What is claimed is:

1. Draw'bench mechanism for sheet forming machines operating on the forming-by-drawing principle comprising a base, a pair of uprights secured'to the base, transversely disposed elongated forming elements supported within and spanning .the uprights in position to have a sheet drawn over them in succession, a gear box supporteduponthe base, .an elongated channel draw bench member supported upon and secured to the 'gear box at a point intermediate its ends, a carriage slidable in the draw bench, a rack on the under side of the carriage, a gear in the gear box operatively engaging the rack, an inward extension on each side of the draw bench constituting an overhang, bearing upon and guiding the respective ,top edges of the carriage, oil passages in the draw bench leading to the under faces of said overhangs, means for delivering lubricating oil under pressure to-said, passages and a draw head attached to and movable with the .carriage and adapted to engage and draw .a sheet ,oversaid forming elements.

2. Draw bench mechanism for sheet forming machines as defined in claim 1 in which theoverhangs extend from the forward end of the bench to a point .on the .gear box at the rear of the engagement of said gear and ,are discontinued rearwardly of said point.

3. Draw bench mechanism for sheet forming machines as defined in claim 2 in which the carriage has full length wear strips on each of its top and bottom edges and the top wear strips have each a discontinuous longitudinaloil groove on its exposed face having longitudinal sections adapted to register successively with the respective oil delivery passage leading to the under face of the overhang, the oil delivery passages being disposedrelative to the length of the oil groove sections .to interrupt delivery of oil to the sections successively before they emerge from under the respective overhangs inthe'return movement of the carriage.

4. Draw bench mechanism for sheet'forming machines as defined in claim 3 in which the bottom'wear strips have each a continuous longitudinal oil groove on its exposed face, together with an oil passage in the draw bench leading to each oil groove in the bottom .wear strips, together with means for delivering lubricating oil under pressure to said last named passages.

5. Draw bench mechanism for sheet forming machines as defined in claim 4 in which the oil passages in the draw bench leading to the under faces of the overhangs branch from the oil passages leadingto the oil grooves in the bottom wear strips.

6. Draw bench mechanism for sheet forming machines as defined in claim 5 together with an oil .pump .in the gear box, power means for the oil pump, and aconduit connecting the pump with each of the oilpassagesin the draw bench leading to the oil grooves in the bottom .wear strips.

7. Draw .benchrnechanism'for sheet forming, machines 'as defined in claim 6 together with lateral Wear strips on the side edges of the carriage, and oil passages inz th e carriage leading from the continuous oil-grooves in the bottom wear strips on the bottom faceof the carriage to the external faces of the lateral wear strips .on therespective side edges of the carriage.

References Cited in the file of this patent UNITED STATES PATENTS McGill May 25, 1909 Moltrup June 30, 1931 Henderson Aug. 8, 1933 De Saussure Oct. 17, 1933 Dempsey June 6, 1939 Hou Dec. 12, 1939 Baker Aug. 10, 1943 10 Picton July 26, 1949 Anderson Sept. 6, 1949 Daugherty July 22, 1952 White Apr. 6, 1954 Daugherty Apr. 13, 1954 Ratzlafl May 18, 1954 Hallden Oct. 23, 1956 FOREIGN PATENTS Great Britain Jan. 20, 1954

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