US2813284A - Head for folding machine - Google Patents

Description

Nov. 19, 1957 H. A. MoNTAlNE 2,813,284

HEAD FOR FOLDING MACHINE /ls 8 se s2 INVENTOR. HERBERT A. MONTAINE ATTORNEY.

N0V 19, 1957 H. A.V MONTAINE HEAD FOR FOLDING MACHINE 2 Sheets-Sheet 2 Filed May 28, 1957 INVENTOR. HERBERT Af. MONTAINE W f @Aw ATTORNEY.

United States Patent @ffice 2,813,284 Patented Nov. i9, 1957 HEAD FOR FOLDING MACHINE Herbert A. Montaine, Lynn, Mass. Application May 28, 1957, Serial No. 662,l68

13` Claims. (Cl. 12--55) This invention relates to rotary folding and pressing machines for folding a cemented or coated binding around the edges of upper stock to which it has been previously stitched and then pressing the binding firmly against the opposite side of the stock to cause the binding to adhere to the stock. More particularly, the invention relates to an improved rotary head for a folding machine of the type described in the patent to Andrew R. Ridderstrom, No. 1,925,205, dated September 5, 1933.

The Ridderstrom machine, which is still in general use, employs as a folding instrumentality a rotary head provided with twenty-two peripheral roller disks rotatable in operation in a direction opposite to that of the head itself. The roller disks are mounted on individual shafts journalled within the head, on the other end of which individual gears are secured positively to rotate the disks. The rotary head is mounted diagonally with reference to the direction of the material feed and cooperation with a lower ridged feed roll, a stationary guide, and a heated retainer foot to effect a turning of the binding over the edge of the stock. The roller disks are mounted in the rotary head at an angle to the axis of rotation of the head and thus in cooperation with the lower feed roll function to feed the stock and bin-ding through the machine, Each of the roller disks is provided with a notch and cam surface on its periphery, these notches being so disposed that the rate of rotation imparted to the disks is such that as each disk reaches a position directly over the lower feed roll, the notch therein is at the lower side of the disk and directly over the ridge on the feed roll. The disks, as the notches therein pass over the ridge on the roller, pull the binding taut away from the stitch line, and then the cam surface is said to provide positive rolling down of the binding edge.

ln spite of many disadvantages of the rotary head of the Ridderstrom machine, it has been in widespread continuous use since its introduction in the early 1920s. The obvious disadvantage of this head is its complexity; it includes twenty-two shafts disposed at an angle in the head, twenty-two close tolerance gears secured to the shafts, and twenty-two roller disks. The notches and cams on the roller disks must be machined after the head is assembled in order to achieve proper timing, and consequently cannot be heat treated to harden them. Consequently, the disks tend to wear out rapidly and experience has shown that when the disks and gears become worn the entire head must be scrapped. Should the head be disassembled for any reason, it is usually necessary to employ a skilled mechanic to adjust the timing of the gears and cams.` In addition to disk wear, the gears and shafts also wear out rather quickly; as would be expected for a mechanism of this complexity, it is designed to `be oiled, but since thevoil is prone to leak out around the several shafts and onto the shoe stock being worked upon, the machine operators (who must pay for the material they damage) are careful not to oil the head. The consequences are obvious.

The basic Ridderstrom machine was designed for fold- 2. ing and laying cemented tape, but has not been altered since the advent of coated binding which must be heated to liquefy the coating preparatory to sealing it against the upper stock. In the folding and rolling process, excess liquefied coating material is squeezed out from under the binding, is sucked into the shaft journals and into the gears, andl upon cooling solidities and gums up the gears thereby causing a requirement for increased driving power. Moreover, the coating material often contains tine abrasive particles which settle in the gear teeth to contribute to rapid wear.

Apart from mechanical deficiencies of the type enu merated, the head also has some functional disadvantages. The timing of the disks with the rotation of the head is such that when all parts are perfect each roller engages the` material before the previous one has left which is claimed to permit the following of abrupt turns in the folded edge. Applicant has found, however, that with a difference in clearance between the lower feed roll and the disks of .005 from one disk to another (a difticult tolerance to maintain in a structure of this complexity) uneven pulling of the binding results, and frequently on abrupt turns the difference in the degree of contact between successive disks may result in one disk losing adequate contact with the work before the next disk engages the work causing unevenness in the laying of the tape and/or throwing of the work from the machine.

Finally, the prior art rotary head does not pull the binding as tightly against the stitching as is desired (a very thin French cord with the stitching exposed is the goal) because of the nature of the folding and laying action of the machine. The guide and the presser foot initiate the folding over of the binding, but the only pulling of the binding away from the stitching is performed by the notches in the disks which press or crush together the binding and leather over the ridge on the feed roll. Thus, the binding is sealed to the leather at a point just forward of the rib on the feed roller as the notch goes by, and thereafter the cam surface of the disk simply rolls over the remaining width of the binding, the latter action in no way contributing to further pulling of the binding away from the stitch line. As a result, the binding is not as tightly pulled as would be preferred, a ridge or roll is formed in the binding at the fold line, and should there be variations in the degree of contact between the feed roll and successive disks (particularly in the notches), the pulling will be uneven and an unsatisfactory French cord will result.

With an appreciation of the enumerated disadvantages and shortcomings of the rotary head of the Ridderstrom machine, applicant has as a general object of the present invention to provide a rotary head -for the machine which overcomes these disadvantages.

Another object of the invention is to provide a rotary head for a rotary folding machine which is simple and inexpensive to construct.

Still another object of applicants invention is to provide a rotary head for a rotary folding machine which has no moving parts and hence is not subject to wear as on existing rotary heads.

Another important object of the invention is to provide a rotary head capable of folding and laying a tighter binding than is possible with existing rotary heads.

Another object of the invention is to provide a rotary head possessing the foregoing advantages which can be directly substituted for the rotary head of the Ridderstrom machine to permit the continued use of the many machines of this type which are now in service.

The machine on which the rotary head is intended for use is the same as that shown in the Ridderstrom patent to which reference may be had for detailed information concerning the points discussed above and for a detailed description of the construction and operation of the other mechanisms of the machine. The improvement forming the subject matter of the present application has to do with a rotary head which cooperates with other parts of the machinegi. e., feed roll, guide and retainer foot, in a manner similar to the rotary head of the Ridderstrom machine to fold and 'lay a binding tape in an improved manner.

ln accordance with the invention, the rotary head comprises a relatively thin circular disk mounted on a shaft to be driven in rotation, the head being mounted diagonally with reference to the direction of the material feed. About the outer periphery of the disk are formed va plurality of ridges and grooves disposed at a small angle to the plane of the disk, which in cooperation with the lower feed rol-l, functions to feed the work through the machine. With the binding spread from the leather stock by the guide, and through the cooperation of the retainer foot and the lower feed roll, the binding is held taut when presented to the ridges on the rotary head. The ridges act to grasp the binding, pulling it taut over the edges of the stock and away from the stitching and pressing the binding down smoothly and evenly with a continuing pulling and wiping action, the effect of which extends across the entire width of the binding. Successive ridges on the disk overlap each other, going around the periphery, whereby the work is at all times held down positively by one ridge engaging the material to a considerable extent before the next previous ridge has left it. Each of the ridges is formed with a step at the extremity thereof which first engages the work to afford positive gripping of the material and permitting the binding of leather of abruptly varying thickness; e. g., from a single thickness of leather to double thickness and back to single, without faltering. The provision of the step also afford a point on the forward extremity of each ridge which first engages the Work at a position near the front face of the disk, such that when the disk is properly oriented with respect to the feed rol-l, the feeding and pulling of the material are focussed at substantially the same point to permit following of abrupt turns without loss of firm pulling contact with the binding.

Other objects, features and advantages of the invention will become apparent, and its construction and operation better understood from the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a side elevation with portions broken away and in Vertical section of the machine embodying the invention;

Fig. 2 is a sectional view of the improved rotary head of the invention and the mounting thereof;

Fig. 3 is a fragmentary side elevation of the rotary head of the invention;

Fig. 4 is a fragmentary end view of the rotary head;

Fig. 5 is a View illustrating the rotary head and the positioning thereof relative to the work support roll;

Fig. 6 is a fragmentary view illustrating the operation ,of the improved rotary head; and

Fig. 7 is a fragmentary plan view further illustrating the operation of the invention.

Referring now to the drawings, and in particular to Figs. 1 and 6, the machine on which the invention is embodied comprises a suitable base lil to which is hinged an upper supporting frame l2 which provides a housing for some of the moving parts of the machine. An overhanging arm 14 extends forwardly from frame 12 and is provided with an oblique bore in which a rotatable shaft 16 is journalled. Secured to the rear end of shaft i6 is a spiral gear 18 meshing with a spiral worm gear Ztl which is carried at the forward end of driving shaft 22 which is suitably journalled in the walls of frame l2. This shaft may be driven by means of a suitable belt pulley (not shown) through a suitable clutch mechanism.

Also journalled in frame 12 is a shaft 24 carrying a worm gear 26 operated from shaft 22 by a worm shaft 28. To the forward end of shaft 24 is connected a shaft Si) on which is mounted a Work supporting roll 32 carried by a support 34. The roll 32 is thus driven in the direction indicated during the feeding and.` folding operations. The forward end of roll 32 may be smooth or knurled steel, or provided with a rubber ring, and has a peripheral guide rib 36. rlhe support 34 carries a guide 38 secured thereto by means of a screw 40, the guide having an upstanding wall 42 adapted to initially position the binding strip when the stock is placed in the machine for the folding operation.

Extending through the front wall of the housing 14 is a shaft 43 which carries a bracket 44, which in turn, at the outer end thereof, carries an inclined guide 46, which may be termed the retainer support. A retainer shaft or spindle 4S is slidingly mounted within guide 46, and is urged downwardly by a compression spring engaging a plate 52 secured to the upper end of the spindle. The compression of spring 50 may be adjusted by nut dita threaded to the upper end of lstud 5017, the other end of which is anchored in bracket 44. Plate 52 slides freely on stud 561; and is further guided by pin 51, also anchored in bracket 44. The lower end of spindle 48 is bi-furcated to provide inner and outer forks 54 and 56 between which a retainer foot roll or disk 58 is rotatably mounted on a suitable shaft. This retainer foot roll is positioned directly above and at an angle to the projecting guide rib 36 on the lower work supporting roll 32, and cooperates therewith to maintain the stitch line on the rib. Retainer guide 46 is provided with a heating element (not shown) which is connected in circuit by means of cable 59 which may be connected to a suitable source of power. The heating element heats the guide 46 and the spindle 48, this heat being conducted to the lower end thereof to heat the forks 54 and 56 to the required temperature to liquefy the cement or gum coating on the binding tape. The coated side of the tape confacts the inner fork 56 whereby the coating is continuously and constantly heated to liquefaction before the tape is folded and pressed down upon the leather.

The machine thus far described corresponds generaliy with the Ridderstrom machine, and no alteration or modi cation is necessary to utilize applicants novel rotary head in place of the complex head of the prior art ma chine. Referring to Figs. 1 and 2, the rotary head in accordance with the present invention comprises a shaft 16 to the rear end of which is secured Worm gear i8, and to the front end of which is secured a circular disk 6l) having a plurality of ridges and grooves on its periphery, the nature of which will presently be described in detail. The shaft is journalled in a bushing 6?, carried in the oblique bore of overhanging arm i4 and secured against rotation by retaining means in tic arm (not shown) cooperating with the bushing. Bushing e2 is preferably provided with a liner 64, of bearing material to prolong its life, and has an opening for the ap.- plication of oil. To provide rigidity and strength to disk 60, and to permit exchange of the disks when worn, a substantially frustro-conical member 63 is secured to shaft 16, as by a key 7), the disk 60 being driven thereby through a pin 72 which engages member 68 and the disk. Disk is maintained in contact with member 63 by a screw 74 threaded into `the end of shaft 16, and shaft lo is retained in the bushing 62 by a retainer ring 76 secured to shaft 16, or by setscrews '7S and Stb, washer S2 formed of fiber or the like preferably being provide-:l as a thrust bearing between the bushing and retainer ring. The assembly just described is positioned in the arm 14 such that the disk 60 is located directly over the roller 32, but at an angle thereto and to the direction of feed movement, More specifically, as shown in Fig.

as rae s4 di'sk 60` isvv mounted directlly` above roller @outwardly of guide rib 36, with the disk 60 substantially contacting the rib 36 and the midpoint' of that portion` of roller 32 which is forward of the rib. As shown in Fig'. l, the point of cooperation of the disk 60 and roller 32 is behind the guide and retainer foot.

Referring now to` Figs. 3, 4 and 5, the disk 60 is formed of steel or similar hard material about 1A: inchthick, the rear face being hat to rest firmly against member 68. The front face of the disk is tapered slightly from the periphery toward the center, a taper of having been found satisfactory. The disk is of slightly larger diameter than member 68, the rear portion, however, being machined to substantially the diameter of member 68, leaving, in effect, a rim about %4 inch wide and of slightly larger diameter. The rim is provided around its periphery with a plurality of spaced grooves 66a, each inclined at equal small angles to the plane of disk 60, to provide a series of ridges 60]; and grooves 60a, each eX- tending around a portion of the periphery of the disk. In a preferred embodiment, disk 60 at the rim is about 23/16 inches in diameter with-twenty-two equally spaced grooves having a width of about .020 inch' cut therein to a depth of about .040 inch, each inclined at anl angle of about 7 degrees to the plane of the disk. Af the intersection of cach groove with the front surface of the` disk, the forward extremity of each ridge is rounded at 60e (as best seen in Fig. 4), and the disk face cut away slightly between adjacent groove termini, as shown at 60d. As best seen in Fig. 5, this construction provides a succession of ridges, each overlapping more that half of the next, and each having in the nature of an inclined step at 60C, which by virtue of the tapered front face of the disk, is the most forward point on the disk. Thus, with rotation of the rotary head in the direction indicated, the point 60e of each ridge is the first to engage the Work material, and the engagement of successive ridges with the material causes a feed of the material in a manner generally similar to that of a screw. The overlapping of successive ridges to the extent provided insures engagement of at least one ridge with the material at all times, and for a large percentage of the time, two ridges engage the material. The inclined steps 60k, on the other hand, permit the abrupt turning of the material (about point 69C) without loss of engagement of the ridges with the material.

As mentioned in connection with Fig. l, and also shown in Figs. 5 and 6, the rotatable headl is mounted on an axis extending at an angle to the direction of feed; i. e., the path of the rim of disk 60 is at an angle with the axis of rotation of feed roller 32. Means is provided for yieldingly pressing the feed roller upward, and the rotary head is positioned directly above the feedroller such that the outer periphery of disk 60 is tangent to two points on the feed roller, at point 36' on the periphery of guide rib 36, and at point 32' substantially midway between the guide rib and the forward end of the feed roll.

Fig. 6 illustrates the application of the machine to the folding of an edge of stock, such as a piece of leather Sil having stitched along its edge at 32 a binding strip 8d, usually of fabric material. In commercial practice, the binding strip is coated along the inner face at S6 with cement or gum. In turning French cord', as illustrated in the present case, the stock is placed in the machine so that the guide rib 36 wi-ll project into the stitch line 82, and as the stock is fed through the machine this guide rib follows the stitch line and' guides the stock, the retainer foot roll 58 traveling along the edge of the material Si) and above rib 36 so as to hold the stock on the guide rib. The binding is tirst spread out and pressed away fromtthe stock at the stitch line by the action of the rib' on feed roll 32,` and the upstanding wall 42 of the guide 33 guides the binding into contact with the heatedl fork 58 of the retainer toot so 6 as to heat the cement or gum coating to liqueii'cation before the binding is folded and pressedY down upon the leather.

The stock is simultaneously fed on and over the feed roll 32 by means ofthe ridges 60b on the periphery of the rotary head. The head is arranged torotate through a path directly behind the retainer foot and guide 42, the ridges being a-t an angle to the direction of feed'. The head is driven in the direction indicated, each of inclined steps 60C engaging the binding as it passes in proximity to guide rib 36 (i. e., approximately at point 36') and drawing it tightly against rib 36 which engages the stitch line 82'. Upon further rotation of the head, the ridges successively engage the binding` and by a wiping action obliquely across the' binding continueto draw it against the guide rib and press it against the leather. It is thus to' be noted that each ridge 60h engages the binding from initial engagement at point: 36' until it rotates past point 32', exerting a` continuing drawing and pressing action throughout the period of enjoyment whcreby a very tightly drawn' cord (sufficiently tight to expose the stitch line on the underside of stock 3G) may be realized. It is to be noted also that the folding and pressing are both accomplished in' the regio-n between points 3'6' and 32', spaced apart of the order of 3/16 inch, but by reason of the inclined .steps 50c at the forwardmost point on the disk, the substantial overlap of successive ridges, and the thinness of the ridged rim, it is possible to make close or abrupt turns in the folded edge and still' preserve an even and uniform fold, which is still further insured by the fact that the feed is continuous and steady- Well before the material is released by one of the ridges, it is engaged by the next succeeding one without the' intermittent release which often occurs with the roller disks of the Ridderstrom head, especiallyl when they become slightly worn.

The' present head construction, again by reason of the steps 60C and the substantial overlap of successive ridges, insures' the layingV of an even and uniform binding on stock of varying texture and thickness. For example, the base' material may change abruptly from single to double thickness and back to single;` the inclined steps 60C, and the continuous drawing action of the ridges prevent hesitation or faltering of the feed when the double thickness is encountered, thus insuring an even and uniform fold. Similarly, the present construction affords the uniform and unfaltering feed of smoothstock, such as patent leather, a material difficult to work on with the Ridderstrom head.

It has been observed that excess gum pressed out from under the folded binding does not collect to any extent in the grooves 60a, but instead collects harmlessly immediately behind the rim, and then without appreciable accumulation by reason of the fact that the surface is smooth. Should the gum accumulate' in the grooves, it may be readily `and quickly'A removed by application of a wire brush while the head is rotating.

Froin the foregoing description, a number of advantages of applicants rotary h'e'ad over the Ridderstrom head will be readily apparent. Apart from the shaft on which it rotates, the head has no moving parts to wear out, and the shaft may be oiled without fear ofI leakage to the work. The head is quieter' in operation than the prior art head and remains clean over extended periods of use. It can be manufactured ata fraction of the cost of the previous" head, and when it becomes worn, the disk 60 can be replaced simply by removal of screw 74, with the remainder of thehead on the machine 'and Without disturbing the setting` of the head relative tothe feed roll. There are no timing problems with the present head, and maintenance can be done by the machine operator. Most important, the construction' of the disk insures `constant engagement with the work` material;` and continuingl pulling of the binding` against the stitch 'line' to produce a tighter, smooth"N er,` and-more uniform binding than is possible with folding machines: now in existence.

While in the description of the invention certain dimensions and angles have been mentioned, it will be understood that the invention is not limited thereto, but are merely by way of example. Applicant is aware also that the invention may be embodied in other specific forms without departing from the spirit thereof, and therefore desires that the disclosed embodiment be considered illustrative, reference being had to the appended claims to indicate the scope of the invention.

What is claimed is:

l. In a rotary folding machine, a rotatable head comprising a circular disk having a plurality of grooves distributed around its periphery and inclined at a small angle to the plane of said disk and forming a like plurality of similarly inclined ridges each 4overlapping a substantial portion of adjacent ridges.

2. In a rotary folding machine, a rotatable head comprising a thin circular disk having a plurality of grooves on its periphery inclined at a small angle to the plane of said disk and terminating at opposite faces of said disk t form a like plurality of similarly inclined ridges each overlapping a substantial portion of adjacent ridges.

3. ln a rotary folding machine, a rotatable head comprising a thin circular disk having front and back surfaces the front surface of which has a small taper from the periphery toward the center, said disk having a plurality of narrow grooves `on its periphery inclined at a small angle to the plane of said disk and terminating at the front and back surfaces of said disk and forming a like plurality of similarly inclined narrow ridges each overlapping a substantial portion of adjacent ridges, each of said ridges at the front face termination thereof being formed with a step.

4. In a rotary folding machine, a rotatable head comprising, a shaft adapted to be driven at one end thereof, a generally cylindrical member secured to the other end of said shaft and having an end face normal to the axis of said shaft, and a thin circular disk having a slightly larger diameter than said member removably secured to the end face of said member, said disk having a plurality of narrow grooves on its periphery inclined at a small angle to the plane of said disk and terminating at the surfaces of said disk and forming a like plurality of similarly inclined ridges each overlapping a substantial portion of adjacent ridges, each of said ridges at the termination thereof with the surfaces of the disk opposite sai-d member being formed with a step inclined `at an angle to a radius of said disk drawn to the said termination.

5. ln a rotary folding machine, a rotatable head cornprising, a shaft adapted to be driven in rotation from one end thereof, a substantially frustro-conical member secured to the other end of said shaft and having an end ace normal to the axis of said shaft, and a thin circular disk, having front yand back surfaces, removably secured to said member with the back surface in engagement with said end face, the front surface of said disk having a slight concave taper from the periphery toward the center, said disk having a plurality of narrow grooves on its periphery inclined at a small angle to the plane of said disk intersecting the front and back surfaces of said disk and forming a like plurality of similarly inclined ridges each overlapping a substantial portion of the length of adjacent ridges, each of said ridges at the intersection thereof with the front surface of said ldisk being formed with a step inclined at an angle to a radius of said disk drawn to said intersection.

6. In a rotary folding machine of the type having a driven feed roll provided with a guide rib, a rotatable feeding and pressing head comprising a circular disk disposed at an angle to said feed roll and tangentially approaching said feed roll at said guide rib and at a point forward of said rib, said disk having a plurality of narrow grooves on its periphery inclined at a small angle to the plane of said disk and terminating at the opposite faces of said disk and forming a like plurality of similarly inclined ridges each overlapping a substantial portion of adjacent ridges.

7. In a rotary folding machine of the type having a feed roll driven about a horizontal axis and provided with ya peripheral guide rib, and a retainer roller disposed above said guide rib, the combination of a rotatable disk inclined at an angle to said feed roll and tangentially approaching said feed roll at said guide rib `and at a point forward of said rib, said disk having a plurality of narrow grooves distributed about its periphery inclined at a small angle to the plane `of said disk and terminating at the opposite faces of said disk and forming a like pluraltiy of inclined ridges each overlapping a substantial portion of adjacent ridges and continuously engaging the work during rotation between said rib and said point.

8. In a rotary folding machine of the type having a driven feed roll provided with a guide rib spaced from the forward end thereof and a retainer roller disposed above said guide rib, the combination of a rotatable head including a shaft adapted to be driven in rotation from one end thereof, a substantially frustro-conical member secured to the other end of said shaft and having an end face normal to the axis of said shaft, and a thin circular disk, having front and back surfaces, removably secured to said member with its back surface in engagement with said end face, the front surface of said disk being tapered inwardly slightly from the periphery toward the center, said disk having a plurality of grooves on its periphery inclined at a small angle to the plane of said disk intersecting the front and back surfaces of said disk and forming a like plurality of similarly inclined narrow ridges each overlapping a substantial portion of the length of adjacent ridges, said disk being inclined at an angle to said feed roll and tangentially approaching said feed roll at said guide rib and at a point forward of said rib, each of said ridges on said disk being of a length greater than the distance between said rib and said point and with the aforesaid overlapping of ridges continuously engage the work during rotation between said rib and said point.

9. Apparatus in accordance with claim 8 wherein each of said ridges at the intersection thereof with the front surface of said disk is formed with a step inclined at an angle to a radius drawn to the point of intersection to provide a point about which the work may be turned and to improve engagement of the disk with work of varying thickness.

l0. In a machine for folding and laying a binding strip stitched to a face of a sheet of material along an edge thereof of the type having a feed roll for feeding the sheet and strip and provided with a guide rib for engaging the said face of the material and the strip at the stitch line to spread the strip away from the material at the stitch line and to guide the material, and a retainer roller for yieldingly pressing the material against the feed roll in the vicinity of said guide rib, the combination of a thin, peripherally ridged disk inclined at an angle to said feed roll and tangentially approaching said feed roll at said guide rib and at a point forward of said guide rib for folding the strip and drawing it away from said stitch line to lay it upon the other face of the material and press it thereagainst.

ll. in a machine for folding and laying a binding strip stitched to a face of a sheet of material along an edge thereof of the type having a feed roll for feeding the sheet and strip and provided with a guide rib for engaging the said face of the material and the strip at the stitch line to spread the strip away from the material at the stitch line and to guide the material, and a retainer roller for yieldingly pressing the material against the feed roll in the vicinity of the guide rib, the combination of a thin disk inclined at an angle to said feed roll and driven in rotation in a direction opposite to the said feed roll, said disk having a plurality of narrow ridges on its periphery inclined at a small angle to the plane of said disk intersecting opposite surfaces of the disk each overlapping a substantial portion of adjacent ridges, the periphery of said disk tangentially approaching said #feed roll at said guide rib and at a point forward of said guide rib for folding said strip and continuously drawing it away from said stitch line to lay it upon the other face of the material and press it thereagainst.

l2. In a folding machine for folding a binding strip ystitched adjacent the edge of a sheet of material of the type including a driven feed roll provided with a guide rib for engaging the material at the stitch line, and a roll at said guide rib and at a point forward of said guide rib and provided on its periphery with a plurality of overlapping narrow ridges inclined at a small angle to the plane of said disk adapted to continuously engage said strip while rotating between said guide rib and said point to fold said strip and draw it away from said stitch line to lay it upon the other face of the material and press it thereagainst.

13. Apparatus in accordance with claim 12 wherein each of said ridges is formed at the extremity thereof which first engages the material with an inclined step to provide a turning point for the material and to positively feed material of varying thickness.

No references cited.

Images