US3335591A - Rail forming machine and method - Google Patents

Description

Aug. 15, 1967 L. HARPER 3,335,591

RAIL FORMING MACHINE AND METHOD Filed June 23, 1965 2 SheetswSheet l INVENTOR LAFFIE HARPER ATTORNEYS Aug. 15, 1967 L. HARPER Filed June 23, 1965 RAIL FORMING MACHINE AND METHOD 2 Sheets-$heet 7 l4 33 I1 ll 5 32 2e 55 32 4| FIG 4 55 W W 'jm 26 Q as as INVENTOR. LAFFIE HARPER BY My 4m, F|G. 8

ATTORNEYS United States Patent 3,335,591 RAIL FORMING MACHINE AND METHOD Laflie Harper, 1192 Montgomery Ave., San Bruno, Calif. 94066 Filed June 23, 1965, Ser. No. 466,186 11 Claims. (Cl. 72-186) This invention relates to a machine for forming rails that are adapted to be secured to the ends of air deflecting vanes for supporting an assembly of such vanes in an air conduit.

One of the objects of the present invention is the provision of a machine for making rails more efliciently than heretofore.

Another object of the invention is the provision of a rotary type rail making machine adapted to make rails having improved means therein for securing both blades of a double vane thereto.

An added object of the invention is the provision of a machine for stamping or forming pairs of blade securing means on a continuously moving strip of sheet metal, the blade securing means of each pair so formed including a portion adapted to substantially follow and engage a transversely curved surface of each blade, thereby providing a more rigid and better fitting connection between the rails and the blades.

Double vanes each comprise a pair of elongated parallel blades curved in cross sectional contour in the same direction and connected along their longitudinally extending edges. One blade has a flatter cross-sectional contour than the other thus providing an arcuately shaped space between them. The end edges of the blades are normally coplanar in a plane disposed at a right angle to the length of the vane.

The rails to which the ends of the vanes have heretofore been connected consist of sheeted material, normally sheet metal. Usually two rows of recesses that open outwardly of one side of each of said rails are formed in said one side with the Walls of each recess projecting to the opposite side of said material. These projections of said walls are equally spaced apart longitudinally of the respective rows and pairs of said projections are in alignment along lines similarly extending at right angles to the rows of projections. The projections in each row are formed with parallel straight slots extending obliquely relative to each row with the slots in one row extending in directions oppositely to the slots of the other row. Where the rails are for double vanes, one blade of each vane projects at each of its ends into one of the slots in each row, a pair of spaced opposed rails being used with the projections formed on said rails projecting toward each other. The portion of the blade that projects into each slot is peened over the portion of the rail in each recess to secure the vanes to the rails. US. Patent No. 2,861,597 issued Nov. 25, 1958, to M. M. Graeer shows examples of conventional structure.

One of the objects of the present invention is the provision of improved means in a rotary stamping machine for forming pairs of slots in a single row extending centrally of the rails longitudinally thereof, and which means merely stretches the material of the rails to one side thereof past the breaking point, without removing any of the material of the rails, to simultaneously form the projections that project to one side of each rail, and a pair of slots in each projection into which one of the ends of both blades of a double vane are adapted to extend.

Another object of the invention is the provision of a machine that is quickly adapted for forming a pair of rows of projections and a pair of slots in each projection for receiving therein the ends of both blades of a double vane. Such rails are used for relatively wide vanes as compared with the rails having only a single row of slots formed therein, but in each instance one of the edges of each slot is in substantial engagement with and follows the arcuate cross-sectional contour of the blade adapted to project into the slot.

An additional object of the invention is the provision of a machine for forming vane securing means in rails, which rails are in the form of a continuous strip drawn from a roll between a pair of power driven rollers, and which machine includes simple means for materially increasing the frictional resistance between the rollers and the strip independently of any force directly applied to the rollers for holding them in engagement with the strip so as to preclude any slippage between the rollers and the strip drawn between them, and, more important, which means insures against undesirable distortion of the rail material by providing a solid backing for the rail material during the formation of the vane securing means thereon.

Other objects and advantages will appear in the description and in the drawings.

In the drawings, FIG. 1 is a side elevational view of the machine including a roll of material from which the rails are formed.

FIG. 2 is a top plan view of the machine of FIG. 1, the roll and the support therefor being omitted.

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is an enlarged, fragmentary, cross-sectional view taken along line 4-4 of FIG. 3, the die elements being shown in elevation and the rail also being shown in crosssection between the rollers.

FIG. 5 is a fragmentary, cross-sectional view along line 55 of FIG. 4, the die element being shown in elevation.

FIG. 6 is a fragmentary plan view of one of the slots.

FIG. 7 is an enlarged, fragmentary, elevational view of a portion of the means for forming the vane securing means on the rail.

FIG. 8 is a plan view of a portion of a rail as it leaves the rail forming machine of FIG. 4.

FIG. 9 is a plan view of the opposite side of a portion of the rail of FIG. 8 showing the blades of a double vane in the slots in said rail.

FIG. 10 is an edge View of the portion of a rail taken along line 10-10 of FIG. 9 but without the blades of the vane.

FIG. 11 is a fragmentary, cross-sectional view of a portion of a rail taken along line 11-11 of FIG. 10.

FIG. 12 is a fragmentary, elevational view showing the arrangement of a pair of slot forming elements in rollers for forming a pair of rows of openings for a relatively wide vane, the outline of the vane being indicated in dot-dash lines where they follow the slots that are to be formed by the slot forming element.

In detail, the machine comprises a frame generally designated 1, that includes a pair of vertically positioned, horizontally spaced opposed side frame members 2 (FIG. 2). Anupper pair of bearings 3 (FIG. 3) rotatably support the ends of a horizontal shaft 4 to which an upper roller 5 is keyed. A gear 6 is secured on one end of shaft 4.

A lower shaft 7 is journalled at its ends for rotation in a pair of lower bearings 11 in the side frame members 2 and a lower roller 8 is keyed to shaft 7. A gear 9 corresponding togear 6 is keyed on one end of shaft 7 with its teeth in mesh with those of gear 6. Also shaft 7 has a relatively large diameter sprocket wheel 10 connected thereto and a sprocket chain 13 extends over wheel 10 and a relatively small diameter sprocket wheel 14 (FIG. 1) spaced therebelow. The latteris on a shaft driven by motor 15.

Upper roller 5 is yieldably urged against lower roller 8 by springs 21 (FIG. 3) yieldably urging bearings 3 downwardly against lower bearings 11. Springs 21 are around rods 12 which extend through bearings 3 into threaded engagement with lower bearings 11 such that bearings 3 are movable vertically relative to the fixed rods 12.

By the above arrangement, actuation of motor 15 will effect rotation of rollers 5, 8 in opposite directions at the same surface speed. The gears 6, 9 positively connect the rollers for being simultaneously driven at the same rate of speed in the direction of the arrows shown in FIGS. 1, 4, so that a strip of rail material 16 from roll 17 (FIG. 1) may be drawn between the rollers for movement from right to left.

Upper and lower vertically spaced guides 18, 19 (FIG. 1) carried on frame 1 function to guide strip 16 from roll 17 to below a horizontal roller or bar 20 that is carried by and extends between the side frame members 2. This bar is so supported at a level below the uppermost level of lower roller 8, and in a position adjacent to said lower roller so that, in starting the strip through the rollers, said strip will be held tightly against the portion of the upper surface of the lower roller leading to the point of engagement between the rollers and the opposite sides of the strip. While this arrangement materially increases the frictional resistance between the rollers and the strip independently of the force of springs 21, it also insures against undesirable distortion of the strip in the forming of the vane securing means on the rail or strip 16 by the die means on the rollers, as will now be described.

FIGS. 4, 5 and 6 clearly illustrate the details of the means on the upper and lower rollers for forming the vane-securing means on the rails.

- The upper roller 5 is cylindrical and is formed with an annular row of equally spaced outwardly opening cylindrically sided recesses 23. In each of these recesses is releasably secured a cylindrical die-body 24 that fits each recess, which body is formed with an annular outwardly opening groove 25. A set screw 26 (FIG. 5) is threadedly supported in the inner end of a radially extending outwardly opening passageway 27 for entering said groove and for releasably holding the body 24 in the desired position within the recess 23.

Body 24 is formed with a pair of parallel slots 28, 29 that are spaced apart a distance approximately equal to the desired distance between the blades of a double vane to be connected to the rail at a point midway between the longitudinally extending edges of such double vane.

A pair of flat sided, slot forming blades 32, 33 (FIGS. 6, 7) are respectively positioned in slots 28, 29, said slots being relatively wide, as seen in FIGS. 4, 6, and their widths being equal to the lengths of slots 28, 29. The latter extend from side-to-side of the body 28 but equally spaced from the central axis of the body 28 (FIG. 6).

The blades 32, 33 have similar linearly convexly curved outer edges 34, 35, respectively (FIG. 5), the ends of which edges terminate at the outer ends of slots 28, 29.

Centrally between slots 28, 29 body 24 is formed with a rectangular projection 36 (FIGS. 6, 7) that has its corners 37 bevelled (FIG. 6). This projection may terminate at its outer end about A; of an inch from the outermost central portion of edges 34, (FIG. 4) and projection 36 may project outwardly of the body 24 about 7 of an inch. These dimensions are not be considered restrictive, but they have been found to be satisfactory for forming the vane securing means for a double vane of approximately 2 /2 to 3 inches in width with a spacing of about /2 inch between the central portions of the blades of such vane. In FIG. 9 the vane blades 38, 39- indicate the two blades of a single vane, it being understood that they are connected along their side edges, substantially as shown in my copending application Ser. No. 452,678, filed May 3, 1965.

The width of the projection 36 in the same direction as the width of blades 32, 33 is substantially less than said width of said blades, and may be approximately /3 the width of the latter.

At the oppositely outwardly facing sides of the blades 32, 33 are projections 40, 41 (FIGS. 6, 7). These projections have their outer surfaces slanted from the outer edges of body 24 to points on said blades slightly less than the distances from body 24 as the projection 36 extends (FIG. 7), and the widths of said projections 40, 41 are the same as the width of said projection 36 (FIG. 6).

The said blades are releasably held in slots 28, 29 and to body 24 by a pin 44 (FIG. 5) that extends transversely through body 24 and coaxial openings in blades 32, 33.

The bodies 24 are releasably held in recesses 23 by set screws 26 so that the blades 32, 33 are parallel with each other and in planes parallel with and equally spaced at opposite sides of a plane extending longitudinally of and bisecting shaft 4.

The outer edge 34 of blade 32 may be called an axe edge in that the blade is bevelled along opposite sides as at 45, 46 (FIG. 6) to provide a double bevel with edge 34 between opposite outer surfaces of said blade. The outer edge 35 of blade 33, on the other hand, may be said to be a chisel edge, since it is bevelled at 47 only on the side adjacent to blade 32. This is one of the features that enables the formation of the desired vane securing means on the rails.

Lower roller 8 is formed with a central outwardly opening continuous annular recess 48 of a width slightly greater than the width of the blades 32, 33 (FIG. 5) and of a depth greater than the distance said blades project outwardly of roller 5.

The roller 5 may be formed with slightly elevated annular radially outwardly projecting ridge 49, adjacent to its ends and lower roller 8 may be formed with a pair of similar radially outwardly projected ridges 50 respectively at opposite sides of each ridge 49 to form ribs in the rail along opposite longitudinally extending edges thereof, and the rollers may, if desired, be formed with as many of these ridges as desired for forming similar ribs in the rail.

In operation (FIG. 4) upon the rail strip 16 being fed to be engaged between rollers 5, 8, it is seen that the rail will be backed by the lower roller before the rail reaches the point where both the rollers engage the strip. This is important to prevent undesirable distortion of the strip 16 by the blades 32, 33 on each body 24 when the blades engage the rail. If the rail were not solidly backed along opposite sides of recess 48 the desired bending and slotting of the rail would not occur.

As the rail is drawn between the rollers, the leading blade 32 will initially engage the upper surface of the rail (as seen in FIG. 4) and said blade, in combination with the leading projection 40 adjacent thereto, together with the central projection 36 will bend the material of the rail downwardly until the material breaks along the line of edge 34, with the result that a relatively narrow slot 53 (FIG. 8), the trailing edge 54 of which, generally conforms, linearly thereof, to the concave curvature of the outwardly facing surface of the inner vane blade 38 (FIG. 9). In FIGS. 9 and 10 and 11 the rail of FIG. 8 is turned over relative to the position of the rail as seen in FIGS. 4 and 8.

In FIGS. 4, 10 and 11, it is seen that the marginal portion 55 of the rail material along the leading edge of slot 53 is bent a substantial distance outwardly of the plane of the rail material and said leading edge is convexly curved linearly thereof. The ends of slot 53 are at the plane of the rail, hence when the end edge of vane blade 38 is cent-rally positioned in slot 53 the edge 54 will substantially engage and follow the curvature of the convex surface of said blade 38.

As the rail continues between rollers 5, 8, the edge of the trailing blade 33 will engage the portion of the rail that has been bent outwardly by the central projection 3 6 and the position of the edge 35 relative to the said projection 36 will result in forming a relatively wide trailing slot 56 (FIG. 8) having a trailing edge 57 of a more pronounced curvature than edge 54, and which edge 57 is curved to substantially conform to the curvature of the outer vane blade 39 of the double vane (FIG. 9). The marginal portion 58 along the edge of slot 56 that is opposite to edge 57 will project even further outwardly of the plane of rail 16 than marginal portion 55, and its edge is curved similarly to the edge along marginal portion 55.

The material of the rail between slots 53, 56, indicated at 59 (FIGS. 4, 9, 10) forms an arcuate bridge between said slots, and the ends of slot 56 also terminate at the plane of the rail, hence when the ends of vane blades 38, 39 are centrally within said slots, the portions of the end edges of said blades that extend outwardly of the ends of the slots 53, 56 will be seated fiat against the side of the rail.

The va-ne blades 38, 39 are secured to the rail, once the end edges are in slots 53, 56 by peening the end marginal portion of the inner blade 38 over the surface of marginal portion of bridge 59 that is in the recessed side of the rail, and by similarly peening over the end marginal portion of the outer blade 39 over the surface of the marginal portion 60 of the rail along the edge 57 of slot 56.

In FIG. 12 a portion of a wider roller 63 is shown, which roller would correspond to roller of FIG. 4, except that it is wider and carries pairs of bodies 24 with the bodies of said pairs aligned axially of the roller and adjacent to opposite ends of the rollers. The bodies of each pair are in annular rows coaxial with the roller, and the lower roller (not shown) would be formed with a pair of outwardly opening recesses each corresponding to recess 48 for receiving the blades 32, 33 on each body 24, including the projections 36, 40, 41.

The arrangement of FIG. 12 is for forming pairs of slots and projections, such as already described, for receiving the end edges of substantially wider vane blades than where a single central row of slots are formed. Merely by positioning the bodies 24 slightly turned relative to the position of body 24 (FIG. 6) so that the blades 32, 33 will be in planes that substantially correspond to the directions in which the vane blades extend at points equally spaced at opposite sides of the medial lines of said blades, the result will be slots and edges thereof that will receive the blades in the same manner as described with respect to FIGS. 8-11, except two rows of slots will be formed instead of one.

In FIG. 11 the crosssectional contour of the inner and outer blades of a wider vane are indicated by dot-dash lines 64, 65 and the positions of blades 32, 33 relative to such lines.

I claim:

1. A machine for forming rails adapted to be connected to the ends of double vanes of the type having differently curved parallel blades connected along two of their opposite edges to provide an inner blade and an outer blade spaced apart between said edges with said inner blade having a concave surface facing away from said outer blade and said outer blade having a convex surface facing in the opposite direction, said machine comprising:

(a) a frame;

(b) a pair of parallel rollers in side by side substantially engaging relation for frictional driving engagement with opposite sides of a strip of sheet metal for driving said strip longitudinally thereof in one direction from an infeed side at one side of said pair of rollers to the opposite side thereof upon rotation of said rollers in opposite directions;

(0) means on said frame supporting said rollers for said rotation thereof;

(d) generally complementary slot-forming means on said rollers respectively comprising a projection extending radially outwardly of one roller of said pair and a radially outwardly opening recess formed in the other roller for receiving therein said projection upon each revolution of said pair of rollers during the interval when said projection and said recess are at adjacent sides of said rollers; and,

(e) means adjacent to said other roller and to said adjacent sides of said pair of rollers for holding said strip tightly against the outer surface of said other roller along the edges of said recess during the period of time when said projection approaches and enters said recess upon said revolution of said rollers with said strip disposed between the latter for driving in said one direction whereby said strip will be slotted by said projection and will be firmly supported against said other roller during said slotting.

2. In a machine as defined in claim 1:

(f) said last mentioned means including an elongated, rigid strip-engaging member parallel with the axes of said rollers supported by said frame in a position at the infeed side of said pair of rollers adjacent to said other roller of said pair and spaced from the closest point between said pair of rollers with said strip being adapted to extend between said member and said other roller, and further including a guide for guiding and supporting said strip for movement into engagement with the outer surface of said other roller at a point prior to movement of said strip between said rollers whereby said strip will be tightly held against the outer surface of said other roller from said last mentioned point to the closest point between said rollers.

3. In a machine as defined in claim 1:

(f) said recess being continuous around said outer roller, whereby said projection may enter said recess at any point therealong.

4. In a machine for forming rails adapted to be connected to the ends of double vanes of the type having differently curved, parallel blades connected along two of their opposite edges to provide an inner blade and an outer blade spaced apart between said edges with said inner blade having a concave outer surface facing one direction and said outer blade having a convex outer surface facing in the opposite direction;

(a) a pair of rollers supported for rotation in opposite directions in side by side substantially engaging relation for driving a strip of sheet metal longitudinally of the latter between them;

(b) an annular row of spaced pairs of slot forming means on one of said rollers projecting radially o-ut- Wardly thereof and engageable with one side of said strip upon the latter being driven between said pair of rollers in said one direction for piercing said strip and for forming a row of pairs of slots extending longitudinally of said strip to form a rail for said vanes;

(c) the other rollers of said pair being formed with an annular outwardly opening recess coaxial with the axis of said other roller for receiving said slot forming means and into which the material of said strip adjacent to said slot forming means is adapted to be bent during piercing of said strip by said slot forming means;

(d) said rollers having cylindrical outer surfaces and a radially outwardly projecting member between each pair of slot forming means for bending the portions of said strip between said pairs of slots into said annular recess to form a bridge between each pair of slots adapted to project into said space between the blades of a vane.

5. In a machine as defined in claim 4:

(e) the said slot forming means of each pair thereof comprising elements having outer edges directed generally radially outwardly of said one roller and convexly curved linearly thereof transversely of the said row of slot forming means for forming each of said slots with an arcuately extending edge adapted to generally correspond in curvature to the curvature of the blades of the vane to be received in each pair of slots.

6. In a machine as defined in claim (f) each of said elements being a fiat-sided blade and the blades of each pair being in opposed relation spaced apart circumferentially of said one roller and said curved edges being the outer edges of said blades and said curved edges having similar curvatures terminating at their ends substantially flush with the outer cylindrical surface of said one roller.

7. In a construction as defined in claim 6:

(g) a body carrying each pair of said blades rigid therewith;

(h) means for securing each body to said one roller at different degrees of rotation of said body relative to said roller about an axis extending radially from said roller whereby the angles of the blades of each pair of blades relative to the row thereof may be varied to change the directions of the slots formed by said blades.

8. A bending and slotting die for use on one roller of a pair of rotating rollers on a rotary stamping machine for forming a pair of slots in a strip of sheet metal for forming a rail for securement of one end of each of the blades of a double vane thereon, and which blades respectively follow different curves about centers at the same side of said vane, to centrally space said blades apart, said die comprising:

(a) a body having lateral sides and an end;

(b) a projection on said end substantially centrally thereof;

(c) a pair of blade-like members on said end of said body at two opposite sides of said projection having substantially parallel edges convexly curved linearly thereof centrally projecting beyond said projection relative to said body and extending at their ends substantially to said end of said body;

((1) said curved edges of said members being sharpened.

9. In a die as defined in claim 8:

(e) means for securing said die to such one roller in a position with said projection and said members projecting radially outwardly of the outer periphery of said roller and with said curved edges extending generally axially of said roller.

10. In a die as defined in claim 8:

(c) said body being adapted to be secured on such one roller at its outer peripheral surface in a position with said curved edges extending generally axially of said roller, whereby one member will be a leading member and the other will be a trailing member 5 upon rotation of said roller in one direction in a stamping operation when such strip is driven between the rollers of such pair;

(f) the opposite sides of said one member of said pair being bevelled to provide an arcuate cutting edge disposed within the confines of the outwardly projected outline of said one member, and the side of the other member that is remote from said one member being bevelled to provide a sharp edge along the side of said other member that is adjacent to said one member, whereby said die when in said position on said one roller and said pair of rollers are rotated in a stamping operation with said strip between them, a pair of slots will be formed in said strip each having a differently curved edge generally respectively conforming to the blade of the vane to be held therein.

11. The method of forming rails for supporting the ends of double vanes in the elbows of air ducts comprising the steps of:

(a) continuously withdrawing a strip of sheet metal the width of said rails from a roll thereof and moving said strip generally in one direction away from said roll;

(b) successively bending to one side of said strip during said movement of the latter localized portions thereof along pairs of lines spaced apart substantially the distance between the central portions of the blades of each such vane, and which lines extend transversely of the length of said strip, until the metal of the strip is separated along each of said lines to form a pair of slots extending transversely of said strip with one slot of the pair being a leading slot and the other slot being a trailing slot, and in which each slot of the pair will have a leading edge and a trailing edge;

(0) during the said bending of each localized portion of said strip to form a pair of slots, bending the material of said strip between each pair of said lines to said one side of said strip whereby the leading and trailing edges, respectively, of the leading and trailing edges of each pair of slots will be in positions offset to said one side of said strip, for projection into the space between the blades of each such double vane when said blades of each vane are in a pair of slots.

References Cited UNITED STATES PATENTS 10,751 4/1854 Ogden 72-l86 272,556 2/1883 Kanaley 72-186 1,801,311 4/1931 Johnson 72186 2,583,682 1/1952 Celovsky 72-186 3,128,816 4/ 1964 Witteloostuyn 72-406 3,142,216 7/1964 Rupnow 83-345,

5 CHARLES W. LANHAM, Primary Examiner.

L. A. LARSON, Assistant Examiner.

Claims (1)

1. A MACHINE FOR FORMING RAILS ADAPTED TO BE CONNECTED TO THE ENDS OF DOUBLE VANES OF THE TYPE HAVING DIFFERENTLY CURVED PARALLEL BLADES CONNECTED ALONG TWO OF THEIR OPPOSITE EDGES TO PROVIDE AN INNER BLADE AND AN OUTER BLADE SPACED APART BETWEEN SAID EDGES WITH SAID INNER BLADE HAVING A CONCAVE SURFACE FACING AWAY FROM SAID OUTER BLADE AND SAID OUTER BLADE HAVING A CONVEX SURFACE FACING IN THE OPPOSITE DIRECTION, SAID MACHINE COMPRISING: (A) A FRAME; (B) A PAIR OF PARALLEL ROLLERS IN SIDE BY SIDE SUBSTANTIALLY ENGAGING RELATION FOR FRICTIONAL DRIVING ENGAGEMENT WITH OPPOSITE SIDES OF A STRIP OF SHEET METAL FOR DRIVING SAID STRIP LONGITUDINALLY THEREOF IN ONE DIRECTION FROM AN INFEED SIDE AT ONE SIDE OF SAID PAIR OF ROLLERS TO THE OPPOSITE SIDE THEREOF UPON ROTATION OF SAID ROLLERS IN OPPOSITE DIRECTIONS; (C) MEANS ON SAID FRAME SUPPORTING SAID ROLLERS FOR SAID ROTATION THEREOF; (D) GENERALLY COMPLEMENTARY SLOT-FORMING MEANS ON SAID ROLLERS RESPECTIVELY COMPRISING A PROJECTION EXTENDING RADIALLY OUTWARDLY OF ONE ROLLER OF SAID PAIR AND A RADIALLY OUTWARDLY OPENING RECESS FORMED IN THE OTHER ROLLER FOR RECEIVING THEREIN SAID PROJECTION UPON EACH REVOLUTION OF SAID PAIR OF ROLLERS DURING THE INTERVAL WHEN SAID PROJECTION AND SAID RECESS ARE AT ADJACENT SIDES OF SAID ROLLERS; AND, (E) MEANS ADJACENT TO SAID OTHER ROLLER AND TO SAID ADJACENT SIDES OF SAID PAIR OF ROLLERS FOR HOLDING SAID STRIP TIGHTLY AGAINST THE OUTER SURFACE OF SAID OTHER ROLLER ALONG THE EDGES OF SAID RECESS DURING THE PERIOD OF TIME WHEN SAID PROJECTION APPROACHES AND ENTERS SAID RECESS UPON SAID REVOLUTION OF SAID ROLLERS WITH SAID STRIP DISPOSED BETWEEN THE LATTER FOR DRIVING IN SAID ONE DIRECTION WHEREBY SAID STRIP WILL BE SLOTTED BY SAID PROJECTIONAND WILL BE FIRMLY SUPPORTED AGAINST SAID OTHER ROLLER DURING SAID SLOTTING.

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