US2191433A - Metal sheet fabricating machine - Google Patents

Description

Feb-20,1940. Y J.J.M 'NQFSKY 2,191,433

METAL SHEET FABRICATING MACHINE I FiledDec. s, 1938 s Sheets-Sheet 1 v INVENTOR JOH/Q J I72AA2OFSKY V O NEYS Feb. 20, 1940. J. MANQFSKY 2,191,433

METAL SHEET FABRICATING MACHINE Filed Dec. 5, 1938 s Sheets-Sheet 2 fl m I g //%\\I v INVENTOR ,1 J. J. MANOFSKYV" 2,191,433

METAL SHEET- FABRICATING MACHINE Filed Dec. 3, 1938 3 Sheets-Sheet 3 INVENTOR JOH/Z v z/v2 OF'SK Patented Feb. 20,1940 7 c v i c UNITED STATES PATENT OFFICE:

John J. Manofsky, Warren, Ohio, assignor to National. Gypsum Company, Bufialo, N; Y.

- Application December 3, 1938', Serial No. 243,809" 14' c aims. .(Cl. 164-65) This invention relates to a machine for fabri- In thedrawings the numerals 10- and H des eating metal sheets and particularly to means ign'ate base members disposed at the feed and therewith for engaging such sheets for purposes discharge ends of the machine-respectively. An of positioning and moving them. intermediate base member (not shown) is pref- The. invention may be advantageously employed erably provided. Extending 'between'the base 5' in the production of expanded metal lath. Ac members and H are spaced be s l3 a cording to the generally accepted method'of prothe construction and operation of which will be ducing-expanded metal lath a sheet of metal is hereinafter'described. a I

first provided throughout'a large part of its sur- The base l0 serves as'a support for forming i 10 face with a plurality of parallel slits, usually roll mechanism which is not shown in detail 0 extending lengthwise of the sheet, and the sheet since such forming roll mechanism is conven' is then gripped at its opposite longitudinal edges, tionally found in machines of the kind under contransversely of the .extent of the slits, and sideration and the forming-roll mechanism enters stretched so that the slits open'up to form a into the present invention only insofar as it promesh. I f .duces sheets of a certain form for introduction The machine of the present invention is deinto the expanding mechanism. 1 signed to effect the stretching of thesheet; or I Actuation of the entire machine may be effected expanding as it is generally known in the art, in by means'of an electric motor l5 which engages an improved manner by providing a machine a conventional speed reducing unitflS through which is adapted to grasp the edges of the sheet the medium' of a flexible coupling [1. A drive 20 in a more eiiicacious manner than has heretoshaft l8 extends longitudinally of the machine fore been the case. i and is jou'rnaled at one end'in bearings l9 and Further advantages of the use of my improved 20 carried by the base Ill. The other end of the metal sheet expanding machine and the improved drive shaft 18 is journaled in a bearing 2| which sheet engaging means will appear from a study "in the drawings is supported by a pedestal 22. 25 v of the drawings and the following description. Disposed upon the right hand end of the base vIn the drawings: I member In as viewed inFigs. 1 and 2 isanele- Fig. 1 is a general plan view of the machine ment 23"having a flat top which serves as a tawith parts broken away; bleupon which previously "slit work sheets are v Fig. 2 is a general side elevational View of the placed for introduction to the machine. I 30 machine, also with parts brokenaway; Adjacent the table member 23 are a pair of Fig. 3 is a cross sectional. view' taken approxispaced b members 24 and 25 which are mately on the line. III-III of Fig. adapted to give support to a plurality of forming 4 is a P p ve w f Several of the rolls. The forming rolls themselves are notinsheet g p elements s ow h in op n and cluded in Fig. 1 of the'drawings but their numin pp position; i 1 her and disposition is' adequately indicated, for 5 is an enlarged elevational View of the the'purpose of exemplificatiomin Fig. 2, where entrance portion f the pa n mechanism the journals of two pairs of rolls, 25, 21 and 28. showing the gripper closing device; 29,'with their associated bearing blocks, appear.

40 Fig. 6 is a plan view of that portion of th The two' pairs of rolls preferably constitute two machine; v passes wherein grooves extending longitudinally Fig s an elevational V Of e delivery ofthe work sheet are formed. Thesegrooves are p n f the pa n nism sh wing t primarily formed in the work sheet tolend added pp r ClOSing device; stiffness to the ultimate product and for other 46 8 s a p an w Of at p n of the structural reasons, but utilization of their presmachine; ence in the unexpanded work sheet is made to Fig. 9 is an end elevational view, also of that the end that the work sheet may be securely and a portion of the machine; and efiicaciously clamped during the expanding op- I Fig. -1O is a diagrammatic view showing aperation'. 50 proximately the appearance of the work sheet The work sheet is impressed, in its passage be- 50 in cross section as it is delivered to the expand tween the forming rolls, with a number of loning mechanism. gitudinally extending V-shaped corrugations. n Fi s. 1 and 2 the cent al part of the ma- One such corrugation will appear-along each chine has been broken away to permit illusmarginal edge .and one or more corrugations may tration on a larger scale. occur at medialv points'across the sheet. In the 55 present invention we are immediately concerned ride between upper and lower pairs. of .guide bars I which engage the marginal corrugations. The

upper guide bars are designated at 36, and the The guide bars are 'so' lower guide bars at 37. arranged that they diverge. in a direction away from the forming roll mechanism and in a horizontal plane. This divergence is for a purpose which will hereinafter appear.

Bracket ill is either secured to or formed upon the pedestal or base member llland gives support to one end of eachof the beams'l3 and I4, their other ends being, as previously stated, disposed upon the other base member An intermediate'pedestal or base member is preferably employed but this is done for added strength only, does not vary the operation of the present invention, and has not been illustrated in the drawings, being brokenaway in Figs. 1 and 2. As may be noted in the plan view, Fig. 1, the beams l3 and i i are substantially divergent in a direction away from the forming rolls which are carried by the base member if]. i

In Fig. 3 the cross section of the left han beam I3 is shown taken at some intermediate point and the cr'oss section of the right hand beam M is taken adjacent its end where it gives support toa sprocket wheel 4!. Similar sprocket wheels are provided in association with each end of each of the beams l3 and [4. The sprocket wheels at the ends adjacent the base member I!) are disposed for idling rotation upon the stub shafts which are journaled in the beams I3 and M as is shown in Fig.3..

The sprockets at the other ends of the beams l3 and i i are connected for joint rotation by a shaft 44, see Fig. 1, a pair of conventional uni-- versal joints 45 and 46 being interposed because each of the sprockets rotates upon an axis at right angles to its associated beam and the pair of sprockets at each end of the machine are consequently not coaxial.

One of the sprockets at the left hand end of the machine as seen in Figs. 1 and 2 is connected to the drive shaft l8 by means of a pair of bevel gears W and 4t. 7

The chain which is associated with the sprockets 4! is of special construction and forms an important part. of the present invention. The chain is shown in cross section in Fig. 3 and several links of the chain are shown in perspective in Fig 4. The chain resembles. a driving chain generally in that it is provided with pairs of side links 56 and center links 5| which pivots ally connect each pair of side links with an adjacent pair of side links by means of pivot pins 52. The center links 5!, however, are in the present invention of novel form and embody'means for selectively clamping the edges of work sheets in a manner which will appear from the following description. 1

Each center link M has rigidly associated with it a hardened steel block 53 having a corrugated upper surface, which corrugations are formed to match the under surface of the corrugated edge of a work sheet such as the one illustrated in Fig. 10. The block 53 may be satisfactorily held in assembly with the center link 5| by the pivot pins 52 which extend through the side and center links 50 and 5| respectively.

An upward extension of each center link 5| is formed to provide a pair of aligned bearings 54, which, throught'he mediurnjof a bearing pin 55 which extends lengthwiseof the chain,'pivotally supports a movable element 58, the movable element being provided for this purpose with a suitable bearing portion 59. In Fig. 4 two such movable elements 58 are shown, the first one from the left being open and the second from the left being inclosed or clamping position.

Each movable element 58 has secured thereto or therein an insert 60, preferably of hardened steel, which has a downwardly disposed V-shaped projection which is complementary with respect to the corrugated block 53 and is adapted to cooperate therewith to engage and clamp the corrugated edge of a work sheet when the movable element is in the position shown at the right of Fig. 4.

Spaced upwardly extending bearing portions 6| are furtherprovided upon the movable element 58 and between them. a roller '62 is rotatably disposed. The bearing pin 63 for the roller has a projection 65 which serves as a sort of cam follower in the opening and closing movements of the elements 58in a manner which will hereinafter appear. The purpose and function of the roller 62 which is associated with each movable element 58 will also become evident further on in this specification.

The sprocket wheels 4|, which for simplicity are not shown in elevation in the drawings, are of usual construction with teeth which fit and enter the openings in the chain. These openings lie between each adjacent pair of center links BI and are further defined by each cooperating pair of side links 50.

The beams IS and Hi have in their upper surfaces longitudinally extending grooves or channels 66 which, in the illustrated embodiment, extend the entire length of each beam. -The lower or relatively stationary portions of the chain, comprising the side and center links, are adapted to travel in this channel and be guided by the walls thereof. To avoid the necessity for replacing the beams when wear occurs as well as to facilitate accurate manufacture in the first instance, lower and side wear plates or blocks in and H respectively are preferably disposed in the channel'68.

, An elongate element 12 of overhanging cross section is fixed along the top of each of the beams l3 and 14 as by screws 13. The overhanging portion M of each of these elements is so located as to overlie its associated chain and means are provided on the former for engagement with the latter for the purpose of keeping the clamping. instrumentalities in closed, or clamping position during certain periods of operation. To further this objective a longitudinally extending pressure bar 75 is associated with the under side of each overhanging portion 14 and in the illustrated instance is set into a longitudinal groove 16 provided therefor in the overhanging portion Screws Tl are disposed in apertures in the overhanging portion 14 and their threads engage the bar 15. The screws I? have free axial sliding movement with respect to the overhanging portion 11 and their length is such that when the bottom of'the pressure bar 15 surrounds the shank of each screw-11, bear.- ing at its lower end against the top of the pressure bar 15' and at its upper end against the bottom: of aheadless screw 8| which is threaded into the overhanging portion 14.

By the means described th'e'pressure bar is caused to exert a resilient downward pressure upon the rollers 62 as they pass therebeneath and thereby hold the movable elements 58 of g the chain in closed position with the edge of a work sheet securely clamped thereby.

The general scheme of operation of the present invention is as follows. The work sheet, after having the edge corrugations formed therein in the forming roll unit carried by the base H! as has previously been described, emerges therefrom and passes to the chain. means where the edge corrugations of the sheet pass onto andin chains at the opposite sides of the machine, in their travel from the sprockets '4! at the forming roll end of the machine to the sprockets at the delivery end of the machine, the previously slit work sheet whichis held at its edges by the clamp ing means of the chain links is caused to 8X- pand in the direction of its width, in a manner well understood in the art, 'to form a sheet of expanded metal lath.

Adjacent the delivery end of the machine further automatic means are provided for opening v the clamping means associated with each chain link successively as-tl'iey reach such automatic means and the means at each end of the machine for so automatically closing and opening the clamping means will now be described.

Figs. 5 and 6 are fragmentary elevational and plan views respectively of the portion of-the ex-- pan'ding mechanism which lies adjacent the forming roll mechanism and which first receives the work sheet therefrom. For simplicity'neither the chain itself nor the sprocket is shown in these figures. An endof the beam I3 is shown and associated therewith the sprocket shaft 42. A semicircular cam ring is supported in substantially-concentric relation with the sprocket and sprocket shaft 42 by brackets 86 secured to the ends of the beam l3. s

The cam ring 85 is of generally uniform thickness in the direction of its radius but its lower portion is thinner at the outside, forming the angularly disposed cam face 81 which merges with the inner truly circular face 88 of the cam ring and at its upper end the cam ring is thinner at the inside as is indicated by the dotted line 89 g to form an angularly disposed cam face which is opposite in inclination to the lower cam face portion 81. i

As the lower reach of the chain, indicated in dot and dash lines at 84 in Fig. 2, approaches the cam ring, in a direction'from left to right as seen in Figs. 5 and 6, the movable elements 58 of the chain occupy approximately the position shown in" the lower right hand corner of Fig. 3, being so disposedv by the force of gravity. The chain link moves into contact 'withthe cam ring with the radial face at the end of the follower pin 64 riding against the angularly disposed portion 81 of the cam face.

As the chain moves about the sprocket the cam-contacting face at the pin '64 reaches'the flat portion 88-'of the cam face. and the movable portion 58 of the chain link is consequently held in the position shown at the left of Fig. 4, that is, in a position where it has been pivotally moved through ninety degrees from a fully closed position. Subsequent to this opening movement of theelement 58 the lateral face of the'element 58 which lies opposite the pin' 64' passes into contact with flat upperface 90 at the extremity of a bracket 9|. 1 Such lateral face of the element 58 is indicated at in the lower right hand corner of, Fig. 3. I

fIhebracket 9| may be'secured to the end of the element 12 as bymeans of the screw 92-and the bracket has an inner vertically extending portion 93, the bracket bein'g twisted so that the inner vertically extending portion merges into the outer somewhat horizontally extending portion. The relieved surface of-the cam ring 85 indicated by the dotted line 89 is really only for clearance since the pivotal movements ofthe movable element 58 are controlled by the cam bracket 9! as soon as the flat face 95 of the movable element 58 rides onto the flat extremity 90 of the bracket 9|. I

As the chain link progresses the contact of the cammingface of the bracket 9| with the portion 95 of the element 58 rotates the'movable element throughninety degrees to the closed position indicated at the top of Fig. 3, the work sheethaving by thistime been fed onto the lower clamping elements 53 of the chain. The chain links then pass-beneath the overhanging portion 14' of the element 12 where the rollers 62 are engaged by the pressure bar 15in a maner which has previously-been described. To simplify the drawings, the'clamp closing instrumentalities of Figs. 5 and 6 have been omitted from Figs. 1 and 2.

After the chains have traversed the entire length of the diverging beams l3 and-l4 and as each link is about to engage its associated sprocket at that end of the machine, it is engaged by cam..-

of each element 12 and having a flat extension thereon which is disposed'vertically adjacent its base portion as at 99 and which is twisted out-- wardlyso that at its extremity. it extends almost horizontally as at I90.

As may be seen from an inspection of Fig. 9,

there is a notch llll in the bottom of the fastening flange of'the bracket 98 through which each link passes as it emerges from beneath the overhanging portion 14 of I the member 12. In so emerging the radial face of the pin 64 of each I movable element 58 of a chain link comes into cammingxcontact with thesubstantially vertically extending portion 99 of the cam bracket 98. It will be obvious that further forward movement of the link will,&by virtue of the camming action of the portions 99 and I80 of the cam bracket 98,. cause the movable elements 58 of the successive links to be pivotedqto an open or non-clamping position, whereupon the work sheet =moves out of contact with the gripping means at the sprocket. and continues its forward motion in. a

straight line as the chain elements follow each other around the sprocket.

I find that highly successful operation results when the sprckets are driven at a speed which gives to the chain elements a surface speed which is approximately two per cent greater than the surface speed'imparted to the work sheets by the forming roll mechanism. This difference results in some slipping of the work sheet in the clamping mechanism but gives to the work sheet while in the clamping mechanism a lengthwise tension which results in a much improved final product and one. which islfree from troublesome surface irregularities which have long been a problem in producing; expanded metal lath.

It will be noted that the work sheet is gripped by an actual mechanical interlock so far as its transverse dimension is concerned but is onlyfrictionally gripped in the direction of its'length. This system of gripping permits the aforementioned sheet tensioning to be accomplished with facility and without reducing the certainty of gripping in the direction of the width of the sheet where, of course, the tensile stress is by far'the greatest and where any slipping will result in an imperfect product.

While a single preferred embodiment of my invention has been illustrated it is not to be considered that my invention is limited thereby or in any other way save as defined in the appended claims.

What is claimed is:

1. In a machine for producing expanded metal sheets, chain means for gripping and conveying pre-slit work sheets having longitudinally extending marginal corrugations, said chain being made up of alternate and pivotally connected center links and pairs of side links, said center links each having a body portion pivotally connected to adjacent side links at each end thereof and a second portion movably associated therewith, said body portion and second portion cooperating to selectively clamp or release a work sheet by interlocking engagement with the marginal corrugations thereof. a

2. In a machine for producing expanded metal sheets from pre-slit work sheets having longitudinally extending marginal corrugations, a pair of gripping and driving chains arranged in spaced relation for cooperation one with each longitudinal edge of the work sheet and a pair of sprockets associated with each chain, said chains extending in diverging directions whereby a work sheet is compelled to assume a constantly increasing width as it is moved along by said driving chains with its' opposite longitudinal edges;

engaged thereby, eachof said chains comprising alternate side and center links pivotally interconnected with their pivotal axes extending parallel to the axes of their associated sprockets, some of said links having clamp-ing elements movably associated therewith for pivotal movement along an axis extending parallel to the path of said chain and adapted to cooperate with their associated links toengage the marginal corrugation of the work sheet and thereby'form releasable clamps.

3. In a machine for producing expanded metal sheets from work sheets having longitudinally extending marginal deformations, a pair of gripping and driving chains arranged in spaced relation for cooperation one with-each longitudinal edge of the work sheet and a pair of sprockets associated with each chain, said chains extending in diverging directions whereby an engaged work sheet is compelled to assume a constantly increasing width as, it is moved along by said driving chains, each of said chains comprising a plurality of link elements interconnected for pivotal movement about axes extending parallel to the axes of their associated sprockets, some of said links having clamping elements movably associated therewith for pivotal movement along an axis extending substantially parallel to the path of said chain and adapted to cooperate with their associated links to-engage the marginal deformationof the worksheet and thereby form releasable clamps.

4. In a machine for producing expanded metal sheets, a pair of gripping and driving chains arranged in spaced relation for cooperation one with each longitudinal edge of a work sheet having pre-formed marginal corrugations and a pair of sprockets associated with each chain, said chains extending in diverging directions whereby an engaged work sheet is compelled to assume a constantly increasing width as it moves along by said driving chains, each of said chains comprising a plurality of interconnected link elements, some of said links having clamping elements movably associated therewith for pivotal movement along, an axis extending parallel to the path of said chain and adapted to cooperate with their associated links to form releasable clamps for interlocking engagement with the marginal corrugations ofthe worksheet, guide means extending along one reach of each of said chainsfor engaging said-chains when said means 'are in clamping relation, said guide means having opposed ,faces for engaging opposite sides of the stationary and movable portions of the clamping links to confine such stationary and movable portions and thereby prevent their separation during substantially the entire period of the passage of the sheet between said diverging chains.

5. In a machine for producing expanded metal sheets from pre-slit work sheets having longitudinally extending marginal corrugations, a driving chain for said sheets comprising a series of links successively interconnected for pivotal movement about axes extending at right angles to their line of travel, some of said links, having corrugations in their upper faces extending in the direction of travel of said chain and adjacent thereto pairs of spaced coaxial bearing portions havingtheir common axis extending in the direction of travel of said chain, a movable element having a bearing portion disposed between each such pair of spaced bearing portions. a pivot pin connecting said movable portion with its, associated link for pivotal movement, the under face of said movable element having a face which is complementary with respect to the corrugations in the-upper face of said link and the formation of both said faces being such as interlock with the marginal corrugation of a work sheet when said movable element is pivoted to bring its lower face toward the upper surface of its associated link.

'tionswith. their common axis extendingisubstantially in the direction of travel -ofsaid chain, a movable element having a bearing portion disposed between saidspaced bearing portions, and I driving chain for said sheets comprising aseries of longitudinally overlapping links successively I interconnected for pivotal movement about axes extending at right angles to their. line of travel, altemate links being substantially contiguous owing to said overlapping-arrangement and each alternate link having spacedcoaxial bearing portions with their common axis extending substantially in the direction of travel, of saidchain, a movable element having a bearing portion dis-.

posed between said spaced bearing portions, and

a pivot pin connecting said movable element with the bearing portionsof its associated link for pivotal :movementsaid movable element and its associated link having complementaryopposed longitudinal corrugations for fin aging the upper and under sides respectively of the marginal por tion of said work sheets for interlocking engagement with themarginal corrugations thereof, the corrugation of said link extending su stantially the full length thereof and the corrugated portion of said movable element being of substantially the same length assaid link whereby the work sheets are 'interlockingly engaged along a major portion of their longitudinal. extent when in engagement with said chain means. l

8. In a machine for producing expanded metal sheets from pre-slit work sheets having longitudinally extending marginal corrugations, a driving chain for said sheets comprisinga series of links successively interconnected for pivotalmovement about axes extending at right angles to their line of travel, some of said links having corrugations in their upper faces extending in the direction of travel of said chain and bearing portions having an axis extending substantially parallel to said corrugations, movable elements associated with said bearing portions for pivotal movement with respect to said links, the under face of each movable element having a face which is complementary with respect to the corrugations in the upper face of itsassociated link and the formation of said upper and lower faces being such as to interlock with'the marginal corrugation of a work sheet when said movable element is pivoted to bring its lower face toward the upper surface of its associated link.

9. In a machine for producing expanded metal sheets from pre-slit work sheets having longi tudinally extending marginal corrugations, a driving chain for said sheets comprising a series of links successively interconnected for pivotal movement about axes extending at right angles to their line of travel, some of said links having corrugations in their upper faces extendingin the direction of travel of said chain and bearing portions havingan axis extending substantially parallel to said corrugations, movable elements associated with saidbearing portions for pivotal movement with respect to said. links, the under face of each movable element having a face which .is'complementary with respect tothe corrugations -in-the upper face of its associated link and the formation of said-upper and lower faces being such as to interlock with the marginal corruga tion of a worksheet when saidmovable element is pivoted to bring, its lower face-toward the upper surface of its associated link, a longitudinally extending track upon which the chain is; 'suported and an overhangingportion associated therewith, and anti-.frictionmeans at the upper side of said movable elements for contact with the under face ,ofisaid overhanging portion to insure positive interlocking between said links, 'fsaid movable elements, and the marginal corrugations of 1 said sheets during the passage of the chain along said track, 1 n

- Y :10. In a machine. for producing expanded metal 2 sheets from 'pre-slit "work sheets having longitudinally extending. marginal corrugations, a

drivingchain" for said sheets comprising a series of. links successively interconnected for pivotal movement. about axes extending at rightangles to their line. of travel, some of "said linkszhaving corrugationsiin their upper faces extending in the direction of travel of said chain and bearing portions havinganaxis extending substantially,

parallel-to said corrugations, movable elements associated-with said bearing portions for pivotal movement with respect to said links, the under face of each movable element having a face which is .complementarywith respect to the corrugations in .theupper face of its associatedlinkand .the formation .of said upper and lower faces being such asto interlock withthe marginal corrugation of. a work sheet when said movable element is pivoted to bring its lower face toward the upper surface of its associated link, a longitudinally extending track upon which the chain is supported, and resilient means: associated therewith and disposed to overlie said chain and engage the upper portion of said movable elementsto resiliently maintain associated links and 'movable elements in interlocking engagement with the marginal corrugations of said sheet.

; 11. In a machine for producing expanded metal sheets from pre-slit work sheets havingrlongi- 1 tudinally extending marginal corrugations, a

driving chain for said sheets comprising a series of links successively interconnected for pivotal movement about axes extending at right angles to their line of travel, some of said links having corrugations in their upper faces extending in the direction of .travel of said chain and bearing portions having an axis extending substantially parallel to said corrugations, movable elements.

associated with said bearingportions for pivotal movement with respect to said links, the v under face of each movable element having a face which is complementary withrespect to the corrugations in the upper face of its associated link and the; v

formation of said upper and lower faces being such as to interlock with the marginal corruga-' tion of a work sheet when said movable element is pivoted to bring its lower face toward the upper surface of its associated link, a longitudinally extending track upon which the chain is supported'and resilient means associated therewith and disposed to overlie said chain, and antifriction means associated with each of themovable elements and adapted to be engaged by said resilient means, said track and said resilient means cooperating to maintain associated links and movable elements in interlocking engagement with marginal corrugations of said sheet during the passage of the chain along said track.

12. In a machine for producing expanded metal sheets from pre-slit work sheets having longitudinally extending marginal corrugations,

a driving chain for said sheets comprising a series of links successively interconnected for pivotal movement about axes extending at right angles to their line of travel, some of said links having corrugations in their upper faces extending in the direction of travel of said chain and bearing portions having an axis extending substantially parallel to said corrugations, movable elements associated with said bearing portions for pivotal movement with respect to said links, the under face of each movable element having a face which is complementary with respect to the corrugationsin the upper face of its associated link and the formation of said upper and lower faces being such as to interlock with the marginal corrugation of a work sheet when said movable element is pivoted to bring its lower face toward the upper surface of its associated link, a longitudinally extending track upon which the chain is supported and an overhanging portion associated therewith, said overhanging portion contacting said movable elements and cooperating with said track to maintain positive interlock between said links, said movable elements, and the marginal corrugations of said sheet during the passage of the chain along the track, and means disposed at opposite ends of said track for moving each movable element into interlocking engagement with its associated link and the work sheet prior to its entry upon the track and for releasing each movable element from such interlocking engagement upon its exit from said track.

' 13. In a machine for producing expanded metal sheets, means for forming marginal longitudinally extending corrugations, said means including means for feeding-said sheets through said forming means at a predetermined rate of speed, mechanism for expanding said sheets including a driving chain for receiving said sheets from said forming means and for moving the same through the expanding mechanism by frictional engagement and means interrelating said feeding means and said driving chains to cause the latter to move faster than the former by a predetermined fractional amount whereby predetermined longitudinal tension is imparted to said sheets upon entry to the expanding mechanism.

14. In a machine for producing expanded metal sheets, means for forming marginal corrugations, said means including means for feeding said sheets longitudinally through said forming means at a predetermined rate of speed, means for expanding said sheets including driving chains for receiving said sheets from said forming means and for moving the same through the expanding means, said driving chains having complementary gripping elements adapted to engage the upper and lower sides of said sheets at said marginal corrugations whereby said sheet is interlockingly held in a-transverse direction and frictionally held in its longitudinal direction, means for interrelating the driving speeds of the drive means associated with the forming mechanism and the driving chainsto cause the latter to move faster than the former in a predetermined degree whereby predetermined longitudinal tension is i imparted to said sheets upon entry to the expanding mechanism.

' JOHN J. MANOFSKY.

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