US3554419A

US3554419A - Nonwoven fabrics

Info

Publication number: US3554419A
Authority: US
Inventors: Leroy E Robinson; Dan E Perry
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1965-03-25
Filing date: 1968-08-01
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12
Also published as: US3424358A; DE1604676B1; NL135191C; NL6603883A; BE678380A; GB1131438A

Abstract

Oriented film is fibrillated between two belts of elastic material by distending the belts in a direction transverse to the direction of orientation of the film by passing pressure means across and in contact with at least one elastic belt so that the component of the velocity of the pressure means that is parallel to the direction of movement of the film is substantially equal to the velocity of movement of the film.

Description

United States Patent Leroy E. Robinson;

Dan E. Perry, Bartlesville, Okla. 749,506

Aug. 1, 1968 Di\ ion of Ser. No. 442,588, Mar. 25, 1965, Patent No. 3.424.358.

Jan. 12, 1971 Phillips Petroleum Company a corporation of Delaware inventors App]. No. Filed Patented Assignee NONWOVEN FABRICS 8 Claims, 5 Drawing Figs.

U.S. Cl 225/93, 28/ l B26f 3/02 Int. Cl Field of Search 98: 28/1 F: 264/(fibrillating digest); 83/326 [56] References Cited UNITED STATES PATENTS 3,111,052 11/1963 Engel 83/326X 3,154,986 11/1964 Reid 83/326X 3,235,644 2/1966 Rasmussen.. 225/3UX 3,350,491 10/1967 Rasmussen 225/3UX Primary Examiner.lames M. Meister Attorney-Young and Quigg ABSTRACT: Oriented film is fibrillated between two belts of elastic material by distending the belts in a direction transverse to the direction of orientation of the film by passing pressure means across and in contact with at least one elastic belt so that the component of the velocity of the pressure means that is parallel to the direction of movement of the film is substantially equal to the velocity of movement of the film.

PATENTEnJAmz mn 7 7 3554419 suiznofa FIBRILLATED 22\ 2 GEAR H 2? BOX FIG.

INVENTORS E. ROBINSON D. E. PERRY A T TORNEKS PATENIEUJANIZIBYI 3554.419

FIBRILLATED FILM INVENTOKS' L.E. ROBINSON A TTORNEYS sum 3 or 3 PATENTEU JAN 1 2 ism INVEN'I'ORS L. E. ROBINSON 0. E. PERRY r W 4;; ATTORNEYS v FIG. 5

NONWOVEN FABRICS This application is a division of our copending application $er. No. 442,588 filed Mar. 25, 1965 now US. Pat. No. 3,424,358.

This invention relates to a method and apparatus for producing nonwoven fabrics from continuous sheet material.

It is known that many synthetic organic linear polymers possess a marked fissility when they have been uniaxially oriented to a high degree and that films ofthese highly oriented films can be split into individual fibers or into a network of coherent fibers by suitable mechanical means such as brushing, rubbing and the like.

Heretofore, in order to make a continuous, high-speed process of splitting an oriented film into fibers or a network of coherent fibers, i.e. fibrillating, a roller or other mechanical device for deforming the elastic belts, and therefore fibrillating the film therebetween, was disposed, relative to the belts so that the device rolled in a direction parallel to the direction of movement of the belts. For example, if a single roller was utilized to deform the belts and therefore fibrillate the film the long, major axis of the roller was disposed so that it was perpendicular to the longitudinal axis and direction of movement of the belts and the roller thus rotated in the same direction as the belts moved.

However, generally the film between the belts is oriented so that the orientation direction thereof is substantially parallel to longitudinal axis and, therefore, the direction of movement of the belts. Since the degree of a fibrillation of the film depends upon the degree of distension of the belts in a direction perpendicular to the orientation direction of the film it is preferred and highly desirable to effect maximum distension of the belts in a direction perpendicular to the longitudinal axis thereof and, therefore, perpendicular to the direction of orientation of the film between the belts. Thus, a maximum degree of fibrillation was not achieved in prior methods since those methods effected maximum distension of the belts, and film therebetween, in a direction parallel and not perpendicular to the direction of movement of the belts.

It has now been found that a continuous, high-speed method of fibrillating a film between two belts of elastic material by distending the belts to the maximum possible extent in a direction perpendicular to the longitudinal axis thereof is effected when the moving belts with the film therebetween have at least one pressure means such as a roller passed across the path of movement of and in contact with the belts in a direction and with a velocity relative to the direction and velocity of movement of the belts such that the component of the velocity of the pressure means that is parallel to the direction of movement of the belts is substantially equal to the velocity of the belts. By this procedure, when the pressure means contacts the belts it is moving in the direction of movement of the belts at a velocity equal to the velocity of the belts and thus the net effect is that the pressure means travels with the belts but at the same time across the belts in a direction of travel perpendicular to both the direction of travel of the belts and the orientation of the film.

It was also found that the above method could be carried oilt by an apparatus utilizing a first pair of endless belts which are elastic and are adapted to meet on the exterior surfaces thereof and move along a fixed line of travel and a pressure means which is adapted to cross the fixed line of travel of the endless belts and contact and distend same. The pressure means is controlled by a mechanism which coordinates the direction and velocity of movement thereof relative to the endless belts as above described. At least one of the endless, elastic belts can be an endless chain of plates, each plate covered by an elastic material so that, in effect, the film is pressed between two elastic surfaces.

Accordingly, it is an object of this invention to provide a new and improved method of fibrillating oriented film. It is another object of this invention to provide a new and improved apparatus for fibrillating oriented film.

Other aspects, objects and the several advantages of the invention will be readily apparent to those skilled in the art from the description, the drawing and the appended claims.

FIG. 1 is a side elevation of apparatus embodying the invcn' tron.

FIG. 2 is a perspective view of the relation'of the elastic belts carrying the film and the roller carrying plates crossing those belts. I

FIG. 3 is a perspective view of another apparatus embodying the invention.

FIG. 4 is a cross section of the pressuring apparatus used in FIG. 3.

FIG. 5 is a cross section ofa part of the apparatus of FIG. 3.

In FIG. 1 there is shown a pair of endless chains of plates 1.1 carried by sprockets 2, 3, 4 and 5 which sprockets are in turn carried by a suitable frame not shown. Chains 1,1 are a series of rotatingly-connected, rigid plates which substantially abut one another when traveling in a straight line between the supporting sprockets. Chains 1,1 are adapted to approach each other on their exterior surfaces in the general area 6 thereby moving individual and opposed

plates

7,7 on each chain into a close but spaced-apart relationship. Chains 1,1 and

plates

7,7 move in this close but spaced-apart relationship along a fixed line of travel and at a first primary velocity before separating in the general area 8 and returning to the general area 6.

A pair of

endless belts

9,9 which are made of an elastic material such as rubber rotate about sprockets I0, 11, 12, 13. l4, l5, l6 and 17. This second pair of belts is adapted to meet on their exterior surfaces in the general area 6 and travel along a fixed line of travel at a second primary velocity and to intersect the line of travel of the pair of belts at an angle. hereinafter referred to as 0, of less than nd to pass between the spaced-

apart plates

7,7 of chains 1,1. A pressure means 18, further describedwith reference to FIG. 2, is carried by

plates

7,7 on at least one of chains 1,1. Pressure means 18 is adapted to extend into the space between spaced-

apart plates

7,7 as indicated by 19 and is further adapted to rotate in a direction perpendicular to the direction of movement of

belts

9,9. That part of pressure means 18 that extends into space 19

contacts belts

9,9 and forces same against a plate 7 on the opposite side of

belts

9,9 thereby applying pressure to belts 9,9 while traveling with same in their direction of travel and at the same time perpendicularly across

belts

9,9.

It should be noted that the lower chain of plates may or may not have pressure means 18 and there can be substituted a stationary backup plate against which

belts

9,9 are pressed by pressure means 18 in the upper chain of plates.

Thus, a continuous, longitudinally-oriented film 20 which is passed between

belts

9,9 is fibrillated by pressure means 18 perpendicularly crossing

belts

9,9 thereby distending the belts to be maximum extent in the direction perpendicular to the direction of travel of

belts

9,9 and the direction of orientation of film 20.

To insure that maximum pressure is applied by pressure means 18 to

belts

9,9 rotating pressure means 21,21 on the interior surfaces of chains 1,1 are positioned on either side of belts 1,1 in the area where

belts

9,9 are passing between

plates

7,7. Although the rotating pressure means 21,21 can be any type of means known, it is preferably a series of stationary rollers disposed throughout the whole length of the zone of coaction, i.e. intersection, between chains 1,1 and

belts

9,9.

Chains 1,1 and

belts

9,9 are driven by a single motor 22 which is connected by 23 to gear box 24 which gear box is arranged internally in a known manner so that gear 10 is driven by pulley 25 and pulley belt 26 at one velocity and sprocket 2 is driven by gear 27 and belt 28 at another velocity. An ar rangement similar to that shown for

gears

25 and 27 and

pulley belts

26 and 28 is arranged on the opposite side of gear box 24, not shown, to rotate pulley 14 and sprocket 4 at the same velocities, respectively, of pulley 10 and sprocket 2. The relative velocity of

belts

1,1 and 9,9 are adjusted through gear box 24 so that the component of the primary velocity of chains 1,1 which is parallel to the fixed line of travel of

belts

9,9 is equal to the primary velocity of

belts

9,9 the primary velocities of chains 1,1 and

belts

9,9 being that velocity parallel to the longitudinal axis of the belts and is directly related to the speed at which pulleys l and I4 and sprockets 2 and 4 are rotated by pulleys on gear box 24.

In FIG. 2 there is shown continuous film between

belts

9,9 and

plates

7,7. Two pressure-rotating means in the form of

rollers

21,21 press against

plates

7,7 as they pass across

belts

9,9.

Single plate has therein a pressure means 18 in a form of a spherical ball which freely rotates in plate 30 and therefore is adapted to rotate in a direction perpendicular to the direction of movement of

belts

9,9. Separate plate 31 shows a pressure means 18 which comprises elongate rollers so oriented with respect to the direction of travel of the plate that they are free to rotate in a direction perpendicular to the line of travel of

belts

9,9. Separate plate 33 shows a pressure means 18 which comprises smaller rollers. In order to insure that maximum coverage of

belts

9,9 with pressure means 18 is effected varying types of pressure means 18 can be employed as the same chain of plates as is shown in FIG. 2; however, a single type of rolling means can be employed throughout in a chain of plates as shown in FIG. 1. Other types of rotating means are contemplated by this invention and will be obvious to those skilled in the art.

The direction of travel of chains 1,1 is indicated by arrow 35 and the direction of travel of

belts

9,9 is indicated by arrow 36, the intersection of which two arrows subtends the angle 0. Arrow 35 is parallel to the longitudinal axis of chains 1,1 and arrow 36 is parallel to both the longitudinal axis of

belts

9,9 and the orientation direction of film 20.

Thus, for a given primary velocity of

belts

9,9 indicated by V there is for a given angle 0 a corresponding primary velocity for chains 1,1 indicated as V which will yield a component designated as V, which is parallel to the primary velocity V and whichis equal in magnitude to V Similarly, primary velocity V for chains 1,1 will have a component V which is perpendicular to the line of movement 36 of

belts

9,9 and therefore indicates the velocity at which rolling means 18 passes perpendicularly across

belts

9,9 thereby distending those belts to a maximum amount in this perpendicular direction. It can thus be seen that the only net relative movement of rotating means 18 while in contact with

belts

9,9 is perpendicular to the longitudinal axis of

belts

9,9.

It should be noted that more than one set of chains 1,1 and/or

belts

9,9 can be employed. Also, more than one set of chains 1,1 can be employed on a single set of

belts

9,9 and vice versa. Further, when more than one set of chains 1,1 is employed with a single set of

belts

9,9 varying angles 0 can be employed and the various chains 1,1 can approach the single belt 9,9'from either side thereof.

This invention applies to any orientable film known in the art such as films of thermoplastic resins, for example, polyalkylenes such as polyethylene, polyamides such as nylon, polycarbonates and polyvinylalcohol. The only requirement for the films is that they be oriented at least uniaxially which orientation can be achieved by any known method such as by stretching the film in a cold or heated state. A preferred method of orienting a film is disclosed in US. Pat. No. 2,943,356 issued to Ole-Bendt Rasmussen on July 5, I960. The films can have a thickness of from one-half to 10, preferably from I to 5, mils.

The product of this invention is a fibrillated film which has great porosity and flexibility in combination with good strength properties and is well suited for use as a nonwoven textile material, filter material and the like.

The velocities of movement of either set of belts is dictated only by the specific apparatus used and vary widely since the apparatus and method are extremely flexible in that the relative velocities of both sets of belts and the angle 0 between same can all three be varied until the desired combination of velocities and angle above described is achieved. All that is required of the primary velocities and their angle 6 is that the ratio of the velocity of belts 9.9 to the velocity of chains 1.1 be equal to the cosine of the angle between them, i.e. the cosine of 0.

FIG. 3 shows an embodiment of the invention wherein the lower elastic, endless belt 9 of FIG. 1 has been replaced by surfacing each plate 7 of the lower endless chain of plates of FIG. 1 with a section of elastic material 40. The section of elastic or resilient material which at least partially, preferably substantially completely, covers each lower plate 7 is preferably composed of the same type of elastic material as upper endless belt 9.

In FIG. 3 the upper endless chain of plates utilizes

single sprockets

41 and 42 and a single chain 43 in lieu of two chains 1, two sprockets 4 and two sprockets 5 as shown in FIG. 1.

Side plates

44 and 45 carry a pressure means that straddles chain 43 and not only applies a vertical pressure to plates 7 but also laterally stabilizes those plates. This pressure means is more specifically shown in FIG. 4.

A means for holding belt 9 against surfaces 40 of lower plates 7 is shown and includes a chain 46 traversing drive sprocket 47,

sprockets

48 and 49, and an unshown sprocket 5 I behind sprocket 41. As shown in FIG. 5, chain 46 carries an inwardly extending pressure member which bears against the inner surface of belt 9 when that belt is in contact with the surfaces 40 of plates 7. Rotating pressure members 51 are fixed to side plate 52 through arms 53 and are adapted to bear against the pressure arm carried by chain 46 thereby binding belt 7 between the pressure arm and a plate 7. Pressure members 51 are rotated by sprockets 54 which engage and are rotated by the movement of chain 46. Chain 46 and belt 9 are both driven by belt 55 so that the chain and the belt move at substantially the same speed. It should be noted that in order to effect substantial identity of speeds of the chain and the belt, the ratios of the diameters of

pulleys

56 and 57 to sprocket 47 and roller 17, respectively, must be substantially the same. Gear and/or drive box 58 can be operatively.connected to the same driving means that runs the other parts of the machine, as shown with gear box 24 in FIG. 1, so that the speeds of the upper and lower chains of plates, belt 9 and chain 46 are all coordinated relative to one another to produce the results of the invention.

FIG. 4 taken along line 4-4 of FIG. 3, shows side plates 44 between which is fixed a support member 60 which straddles chain 43 and which, through angled rollers 61 and 62, contacts shoulders 63 and 64 of plate 7. The angled nature of rollers 61 and 62 provides both the vertical force for pressing rollers 18 against belt 9 and for preventing plate 7 from moving laterally relative to support member 60.

FIG. 5, taken along line 5-5 of FIG. 3, shows sprockets 3 engaging plates 7 through parallel chains attached to plates 7.

Side plates

52 and 70

fixedly support members

71 and 72, respectively, each of which rotatably carry a roller 73. Rollers 73 engage shoulders 74 of plates 7 thereby applying both vertical forces and laterally opposing forces to plates 7. Thus, plates 7 are forced upward towards the upper chain of plates and prevented from laterally moving from their direction of movement.

Pressure arm 75 carried on the interior side of chain 46 is disposed above shoulder 76 of plate 7 so that it will press belt 9 (not shown) into contact with shoulder 76 thereby holding belt 9 in a fixed relation to and against plates 7. Rotating pressure member 51 driven by chain 46 through sprocket 54 en sures positive pressing of arm 75 against both belt 9 and shoulder 76. Although ann 75 and shoulder 76 are shown to have teeth in the area in which belt 9 is gripped, it should be noted that other or no auxiliary gripping means can be employed.

EXAMPLE An apparatus similar to that shown in FIG. 1 was employed in which

belts

9,9 were endless rubber belts and chains 1,1 were made up of a series of pivotally connected plates each plate having mounted therein l2 cylindrical rollers 1 1/16 inches long and 1 l/l6 inches in diameter. The rollers were arranged in a series similar to that shown in plate 33 of FIG. 2 and each plate of both chains has a similar arrangement of similar rollers. The rollers were laterally spaced from one another a distance of 1.142 inches. Chains 1,1 were oriented with respect to

belts

9,9 so that they crossed those belts at an angle 6 of 35. The velocity, V,,, of the

belts

9,9 was 150 feet per minute and the velocity, V of the chains was 183.2 feet per minute.

Polyethylene film was uniaxially oriented parallel to its longitudinal axis by stretching of same, having a density of 0.96 and a thickness of 3 mils. The film removed from between

belts

9,9 after passing between chains 1,1 was fibrillated in that it was a weblike network of coherent fibers randomly drawn to one another along a longitudinal length thereby forming a nonwoven fabric having good strength properties combined with a significant amount of porosity and flexibility.

Reasonable variations and modifications are possible within the scope of this disclosure without departing from the spirit and scope thereof.

We claim:

1. Apparatus for making fibrillated film comprising a frame, a pair of elastic means carried by said frame and adapted to meet in an abutting relationship and pass along a fixed line of travel in that relationship before being separated and returned to be moved again into said abutting relationship, pressure means carried by said frame and adapted to cross said fixed line of travel of said elastic means and to contact and distend said elastic means in a direction substantially perpendicular to the direction of movement of said elastic means, and means carried by said frame to move said pressure means in a direction and at a velocity across said elastic means such that the component of velocity of said pressure means which is parallel to the direction of movement of said elastic means is substantially equal in magnitude to the velocity of said elastic means in said direction of movement.

2. Apparatus according to claim 1 wherein said elastic means is an opposing pair of endless belts.

3. Apparatus according to claim 1 wherein said elastic means is an endless belt and an opposing endless chain of plates each plate carrying a section of resilient material between itself and the endless belt.

4. Apparatus according to claim 1 wherein said pair of elastic means carried by said frame is adapted to meet and travel along a fixed line of travel at a first primary velocity, at least one pressure means is carried by said frame and adapted to move along a fixed line of travel at a second primary velocity, a backup means is carried by said frame, said elastic means and pressure means are mounted on said frame so that they intersect the line of travel of each other at the location of said backup means at an angle of less than 90 and said elastic means pass between and are pressed together by said pressure means and said backup means, and means is provided to move both said elastic means and said pressure means it a rate such that the component of the primary velocity of said pressure means which is parallel to the fixed line of travel of said elastic means is substantially equal to the primary velocity of said elastic means.

5. Apparatus according to claim 1 wherein a pair of endless chains of plates is carried by said frame and adapted to approach each other on their exterior surfaces and hold opposing plates on each chain in a close but spaced-apart relationship while moving along a fixed line of travel in said relationship at a first primary velocity before'separuting and returning to again be moved into said spaced-upart relationship, said elastic means is a pair of elastic endless belts carried by said frame and adapted to meet on the exterior surfaces thereof and travel along a fixed line of travel at a second primary velocity which has a component which is parallel to the line of travel of said pair of chain of plates, said pair of belts and said pair of chains of plates being mounted on said frame so that they intersect the line of travel of each other at an angle of less than nd said belts pass between said spaced-apart plates of said chains, rotating means carried by the plates in at least one of said pair of chains of plates and extending into the space between said plates when in said spacedapart relationship and adapted to rotate in a direction perpendicular tot'ne direction of movement of said belts, rotating means fixed on the interior sides of said pair of chains of plates mounted in the area where said chains intersect said pair of belts and adapted to force said chains toward one another and force said rotating means in said plates against said belts along the length of intersection of said belts and said chains, and means to move both said belts and said chains at a rate such that the component of the primary velocity of said chains which is parallel to the line of travel of said belts is substantially equal to the primary velocity of said belts.

6. Apparatus according to claim 1 wherein said pressure means carried by said plates comprises atleast one roller.

'7. Apparatus according to claim 3 wherein said endless belt is held relative to said chain of plates by a holding means comprising an endless chain carrying a pressure arm adapted to approach said chain of plates, and a rotatable pressure means rotated by movement of said chain and adapted to engage the pressure arm of said chain and force same to approach said chain of plates.

8. Apparatus according to claim 1 wherein a pair of endless chains of plates is carried by said frame and adapted to approach each other on their exterior surfaces and hold opposing plates on each chains in a close but spaced-apart relationship while moving along a fixed line of travel in said relationship at a first primary velocity before separating and returning to again be moved into said spaced-apart relationship, said elastic means comprises an elastic endless belt adapted to meet one of said pair of chains of plates on the exterior surfaces thereof and travel between said close but spaced-apart pair of chains of plates and travel along a fixed line of travel at a secondary primary velocity which has a component which is parallel to the line of travel of said pair of chains of plates, the plates of one of said pair of chains of plates carrying an elastic member between the plate and the endless belt, said belt and said chains of plates being mounted on said frame so that they intersect the line of travel of each other at an angle of less than 90, rotating means carried by the plates in at least one of said pair of chains of plates and extending into the space between said plates when in said spaced-apart relationship and adapted to rotate in a direction perpendicular to the direction of movement of said belt, rotating means fixed on the interior sides of said chains and mounted in the area where said chains intersect said belt and adapted to force said chains towards one another and therefore force said rotating means in said plates against said belt along the length of intersection of the said belt and said chains, and means to move both said belt and said chains at a rate such that the component of the primary velocity of said chains which is parallel to the line of travel of said belt is substantially equal to the primary velocity of said belt.

Disclaimer and Dedication 3,554,419.-Ler0 E. Robinson and Dan E. Perry, Bartlesville, Okla. NON- VVOVE FABRICS. Patent dated Jan. 12, 1971. Disclaimer and dedication filed Dec. 28, 1971, by the assignec, Phillips Petroleum 001m pany. Hereby disclaims said patent and dedicates to the public the remaining term of said patent.

[Oflicial Gazette April 11, 19753.]

Claims

2. Apparatus according to claim 1 wherein said elastic means is an opposing pair of endless belts.
3. Apparatus according to claim 1 wherein said elastic means is an endless belt and an opposing endless chain of plates each plate carrying a section of resilient material between itself and the endless belt.
4. Apparatus according to claim 1 wherein said pair of elastic means carried by said frame is adapted to meet and travel along a fixed line of travel at a first primary velocity, at least one pressure means is carried by said frame and adapted to move along a fixed line of travel at a second primary velocity, a backup means is carried by said frame, said elastic means and pressure means are mounted on said frame so that they intersect the line of travel of each other at the location of said backup means at an angle of less than 90* and said elastic means pass between and are pressed together by said pressure means and said backup means, and means is provided to move both said elastic means and said pressure means it a rate such that the component of the primary velocity of said pressure means which is parallel to the fixed line of travel of said elastic means is substantially equal to the primary velocity of said elastic means.
5. Apparatus according to claim 1 wherein a pair of endless chains of plates is carried by said frame and adapted to approach each other on their exterior surfaces and hold opposing plates on each chain in a close but spaced-apart relationship while moving along a fixed line of travel in said relationship at a first primary velocity before separating and returning to again be moved into said spaced-apart relationship, said elastic means is a pair of elastic endless belts carried by said frame and adapted to meet on the exterior surfaces thereof and travel along a fixed line of travel at a second primary velocity which has a component which is parallel to the line of travel of said pair of chain of plates, said pair of belts and said pair of chains of plates being mounted on said frame so that they intersect the line of travel of each other at an angle of less than 90* and said belts pass between said spaced-apart plates of said chains, rotating means carried by the plates in at least one of said pair of chains of plates and extending into the space between said plates when in said spaced-apart relationship and adapted to rotate in a direction perpendicular to the direction of movement of said belts, rotating means fixed on the interior sides of said pair of chains of plates mounted in the area where said chains intersect said pair of belts and adapted to force said chains toward one another and force said rotating means in said plates against said belts along the length of intersection of said belts and said chains, and means to move both said belts and said chains at a rate such that the component of the primary velocity of said chains which is parallel to the line of travel of said belts is substantially equal to the primary velocity of said belts.
6. Apparatus according to claim 1 wherein said pressure means carried by said plates comprises at least one roller.
7. Apparatus according to claim 3 wherein said endless belt is held relative to said chain of plates by a holding means comprising an endless chain carrying a pressure arm adapted to approach said chain of plates, and a rotatable pressure means rotated by movement of said chain and adapted to engage the pressure arm of said chain and force same to approach said chain of plates.
8. Apparatus according to claim 1 wherein a pair of endless chains of plates is carried by said frame and adapted to approach each other on their exterior surfaces and hold opposing plates on each chains in a close but spaced-apart relationship while moving along a fixed line of travel in said relationship at a first primary velocity before separating and returning to again be moved Into said spaced-apart relationship, said elastic means comprises an elastic endless belt adapted to meet one of said pair of chains of plates on the exterior surfaces thereof and travel between said close but spaced-apart pair of chains of plates and travel along a fixed line of travel at a secondary primary velocity which has a component which is parallel to the line of travel of said pair of chains of plates, the plates of one of said pair of chains of plates carrying an elastic member between the plate and the endless belt, said belt and said chains of plates being mounted on said frame so that they intersect the line of travel of each other at an angle of less than 90*, rotating means carried by the plates in at least one of said pair of chains of plates and extending into the space between said plates when in said spaced-apart relationship and adapted to rotate in a direction perpendicular to the direction of movement of said belt, rotating means fixed on the interior sides of said chains and mounted in the area where said chains intersect said belt and adapted to force said chains towards one another and therefore force said rotating means in said plates against said belt along the length of intersection of the said belt and said chains, and means to move both said belt and said chains at a rate such that the component of the primary velocity of said chains which is parallel to the line of travel of said belt is substantially equal to the primary velocity of said belt.