US3035512A - Flexible nip loading arrangement - Google Patents

Description

y 22, 1962 E. D. BEACHLER 3,035,512

FLEXIBLE NIP LOADING ARRANGEMENT Filed May 19, 1958 s Sheets-Sheet -1 Maria? Edward D. Beach [er Z: 7 7 w "H :2 7 35 May 22, 1962 E. D. BEACHLER 3,035,512

FLEXIBLE NIP LOADING ARRANGEMENT Filed May 19, 1958 6 Sheets-Sheet 2 i v v Edward D. Beach /ez" y 22, 1962 E. D. BEACHLER 3,035,512

FLEXIBLE NIP LOADING ARRANGEMENT Filed May 19, 1958 6 Sheets-Sheet 3 he EZQ 2'" Edward D. Beach/gr b H Z Z y 2, 1962 E. D. BEACHLER 3,035,512

FLEXIBLE NIP LOADING ARRANGEMENT Filed May 19, 1958 6 Sheets-Sheet 4 I24- I LUKE :EZUT

E. D. BEACH LER FLEXIBLE NIP LOADING ARRANGEMENT e Sheets-Sheet 5 May 22, 1962 Filed Ma 19, 1958 Edward D. Beach/er May 22, 1962 E. D. BEACHLER FLEXIBLE NIP LOADING ARRANGEMENT 6 Sheets-Sheet 6 Filed May 19, 1958 he ILZUT Eaararz/ fl. Beach/er QNN E United States Patent Office 3,@35,5l2 Patented May 22, 1962 3,035,512 FLEXIBLE NIP LOADING ARRANGEMENT Edward D. Beachler, Beloit, Wis., assignor, by mesne assignments, to Clupak, Inc., New York, N.Y., a corporation of Delaware Filed May 19, 1958, Ser. No. 736,161 3 Claims. (Cl. 100-160) The instant invention relates to apparatus for applying pressure to a traveling flexible element, and more particularly, to a controlled flexible nip loading arrangement.

The application of pressure to a traveling flexible element passing between opposed nip-defining surfaces (such as may be presented by opposed pressure rolls) is employed in a number of arts. For example, nip-defining pressure rolls are used to squeeze moisture from textiles or paper traveling therebetween; and in such arrangements control is provided essentially for the actual loading pressure at the nip. In the case of doctor nips in coating devices for textiles or paper, the loading pressure is controlled and also the space between the nipdefining surfaces involved must be controlled. Such space must be suiflcient to permit not only the fabric but a layer of coating thereon to pass through the nip. Control of this space merely by control of the actual loading pressure is often inadequate.

Although the instant invention may have application in any of the nip loading arrangements hereinbefore contemplated, it is particularly useful in connection with the art of making extensible paper and it will be described primarily in connection therewith. In the art of making extensible paper there has just been developed an arrangement wherein a resilient blanket is urged against a paper web over an extensive peripheral area of a heated roll. At approximately the point at which the paper web covered by the blanket engages the heated roll, a backing member defines a press nip with the heated roll so as to squeeze the rubber blanket in a predetermined manner. During the remainder of its travel over the specified peripheral area of the heated roll, the squeezed rubber blanket returns to its original size and shape with the result that the portion of the paper Web covered thereby on the previously selected peripheral area of the roll is subjected to longitudinal compacting or compression. The instant invention is concerned primarily with the nip loading arrangement for such backing roll which permits a rather substantial amount of space between the backing roll and the heated roll surface so that an appreciable thickness of the rubber blanket may pass through the nip. On the other hand, the instant nip loading arrangement permits the application of substantial pressure to the blanket at the nip.

In the instant device, and in a number of other nip loading arrangements, it has been found desirable to employ a backing roll (as one of the two nip-defining rolls) of relatively small diameter. This results in the formation of a nip having a minimum peripheral dimension. Such a nip more accurately applies the precise loading pressure desired. The use of a roll of relatively small diameter, however, results in a tendency for this roll to bend generally in the plane in which the nip loading pressure is applied (i.e., the plane containing the axes of both the nip-defining rolls). Also, nips of this type have an extensive lateral dimension (laterally with respect to the direction of travel of the flexible element passing through the nip), so that liquids such as moisture or lubricants employed may actually develop by hydraulic forces in the central portion of the nip so that much greater loading pressure is required to maintain a predetermined space between the nip-defining rolls.

In Canadian Patent No. 546,471, issued to Appenzeller, there is described a nip loading arrangement involving the use of laterally spaced pairs of opposed rollers for backing a nip-defining roll. Each of such pairs of opposed rollers is resiliently urged against the back of one of the nip-defining rolls. The resilient means thus act through the associated pair of rollers to load one nipdefining roll directly against the other and no means are provided for maintaining a desired space between th nip-defining rolls. It will be appreciated that, the instant invention provides an arrangement whereby spacing between the nip-defining surfaces may be maintained to a predetermined extent independently of the actual loading pressure applied. In this way, the desired spacing may be maintained across the full lateral dimension of the nip, even though hydraulic forces or the like in the flexible element passing through the nip may resist nip loading to a greater extent, for example, in the central portion of the nip than at the edges. Irregularities in forces resisting nip loading within the traveling flexible element may also be created by varying the actual spacing of the nip across the lateral dimension thereof. The instant invention also provides for such variation in the actual spacing across the lateral dimension of the nip and the use of nip loading pressures in conjunction with such spacing to maintain the predetermined spacing across the width of the nip in spite of irregularities or differences in the forces within the traveling flexible element which resist nip loading.

The instant invention provides for laterally spaced members engaging one of a pair of nip-defining means for nip loading purposes. Such members are each provided with independent fluid pressure actuated means for applying the loading force and adjustable stop means for maintaining the desired spacing at the nip. In addition, such members are pivotally mounted to permit limited movement toward and away from the nip and limited tilting movement along an axis extending longitudinally in the direction of travel of the traveling flexible element passing through the nip. Such tilting movement provides for better alignment between the individual spaced members and the nip-defining roll backed thereby.

It is, therefore, an important object of the instant invention to provide an improved nip loading arrangement.

It is another important object of the instant invention to provide apparatus comprising a pair of means presenting opposed nip-defining surfaces for pressing a traveling flexible element passing therethrough, laterally spaced members engaging one of said pair of means, fluid pressure actuated means acting on each of said members to urge said one of said pair of means toward the other, and separate adjustable stops operatively connected with each of said fluid pressure actuated means to limit the movement of said one of said pair of means toward the other.

Other and further objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed disclosure thereof and the drawings attached hereto and made a part hereof.

On the drawings:

FIGURE 1 is essentially a diagrammatic side elevational view of an extensible paper making apparatus including the nip loading arrangement of the instant invention;

FIGURE 2 is a fragmentary essentially diagrammatic front elevational view taken from the right hand side of FIGURE 1; t 1

FIGURE 3 is a detail sectional elevational view of a nip loading arrangement embodying the instant invention;

FIGURE 4 is a front elevational view taken from the right hand side of FIGURE 3;

FIGURE 5 is a sectional elevational view taken substantially along the line V--V of FIGURE 3;

FIGURE 6 is a detail sectional elevational view showing the mounting of the centering pin (shown in full elevational view) in FIGURES 3 and 4;

FIGURE 7 is a side elevational view of another nip loading arrangement embodying the instant invention; and

FIGURE 8 is a detail elevational view of one of the nip-defining members of the embodiment of FIGURE 7, showing the same partially in full elevation and partially in section.

As shown on the drawings:

In FIGURES l and 2 there is shown diagrammatically a device, indicated generally by the reference numeral 10, for making extensible paper. The device 10 comprises a resilient endless rubber blanket 11 mounted on guide rolls 12, 13, 14, 15 and 16. The rubber blanket '11 passes through a nip N-1 defined by a first cylinder 17 rotatably mounted on hearing means 17:: and a second cylinder 18 mounted on fixed bearings 18a. The blanket 11 is held against the second cylinder or roll 18 over a substantial peripheral area 18b extending from the first cylinder or nip roll 17 to a second roll 15; and a paper web W is guided into contact with the surface of the roll 18 just before the nip N-l and is held against the surface of the roll 18 until the rubber blanket turns around the guide roll 15. The rubber blanket 11 is squeezed or compressed at the nip N-l and it gradually returns to its normal size and shape as it passes over the peripheral area 18b toward the guide roll 15. The main press roll 18 is heated and the moisture in the paper Web W subjected to the heat from the roll 18 afiords some lubrication so that the web W is longitudinally compressed as it passes over the peripheral roll area 1812.

A plurality of members 20, 21, 22, 23 and 24 (FIG- URE 2) are spaced across the width of the nip N-l. As indicated in FIGURE 1, the first member comprises a pair of opposed rollers 20a and 2% which engage the back side of the cylinder 17. The same is true of the members 21, 22, 23- and 24. The bearings of the rollers 20a and 20b are carried by an arm 20c connected to a fixed pivot 20d at one end thereof, for swinging the rollers 20a and 20b about an axis aligned with the pivot 20d and parallel to the line of the nip N1. Atthe opposite end of the arm 200 there is a pivot 20c movable with the arm 200. As shown in FIGURE 2, each of such pivots Me, 212, 22c, etc. is connected to a yoke 30, 31, 32, 33 and 34, respectively. A separate fluid actuated means 40, 41, 42, etc. is connected to each of said yokes 30, 31, 32, by means of pivots 50, 5 1, 52, etc. so as to permit limited relative tilting movement between the fluid pressure actuated means or diaphragms 40, 41, 42, etc. and the yokes 30, 31, 32, etc. about an axis aligned with the pivots 50, 51, 52, etc. and longitudinally aligned in the direction of travel of the blanket 11 passing through the nip N-1.

As shown in FIGURE 1, adjustable stop means 60 are provided for each pressure actuated element or diaphragm 40, so that the downward thrust of the fluid pressure actuated means 40 is limited, thus in turn limiting the actual spacing between the cylinders 17 and 18 at the nip N-l. The details of the adjustable stop means 60 will be described hereinafter.

Referring now to the specific embodiment of FIGURES 3, 4 and'S, it will be seen that a large roll 100 is shown only fragmentarily in FIGURE 3 with a nip-defining surface 100:: opposite a nip-defining surface 101a of a second roll 101. The nip N-2 receives a traveling flexible element in the form of a rubber blanket B-1 and a paper web W-2. The space S between the nip-defining surfaces 100a and 101a is slightly less than the thickness of the blanket B-1, so that the blanket B-'1 is squeezed at the nip As shown in FIGURES 3 and 4, the roll 101 is rotatably mounted on bearings within housings 102, 102 at opposite ends of the roll 101. The bearing housing 102 has a threaded socket 102a at its top which threadedly receives a centering pin 103. The centering pin 103 is locked in a sleeve 104 by lock nuts 105 and 106 and the sleeve 104 is mounted on a frame element 107 suitably secured to bearing housings 108a and 10901 formed in an arm 110.

As will be noted from FIGURE 4, opposed bearing housings 109a and 109cc rotatably mount a backing roller 109 which engages the back side of the press roll 101. Directly behind the bearing housings 109a and 109a in the position of FIGURE'4 there are opposed bearing housings for a second roller 108; and the position of the roller 108 and one of the bearing housings 108a is shown in FIGURE 3. The bearing housings 108a and 109a are formed in one arm 110 and the opposite bearing housings are formed in a second arm generally symmetrical in configuration to the arm 110 shown only partially at 110' in FIGURE 4. The arm 110' does not have a frame ele ment 107 and centering pin 103 mounting, but such a mounting is provided at the opposite end of the press roll 101. This general position of the centering pins is indicated diagrammatically in FIGURE 2, wherein it will be noted that centering pins P and P are connected to opposite bearing housings 17a, 17a for the top roll 17.

Referring to FIGURE 6, it will be noted that the centering pin 103 is received by the sleeve 104 mounted on the frame element 167, but a resilient elastomer sleeve 111 is interposed between the frame sleeve 104 and the centering pin 103 so as to permit relatively slight tilting movement of the pin 103 in the sleeve 104. Also, an elastomer washer 112 is clamped against the frame sleeve 104 by a metal washer 113 held in place by the top lock nut 105; and another elastomer washer 114 is clamped against the bottom of the frame sleeve 104 by a metal Washer 1 15 held in position by the lower lock nut 106. The washers 112 and 114 as'well as the elastomer sleeve 111 are formed of relatively hard rubber so that they yieldingly hold the centering pin 103 in position, but they do permit a relatively limited amount of tilting movement of the pin 103 (with only a negligible amount of relative axial movement between the pin 103 and the frame sleeve 104). The purpose of this mounting for the pin 133 is to permit slight shifting of the bearing housing 102 and thus the roll 101 relative to the backing rollers 10S and 109 during the relatively slight movement of the arm 110. As will be appreciated, the arm 110 is moved slightly so as to adjust the space S between the rolls 101 and 100 and the movement of the arm 110 will be described in detail hereinafter. This slight movement of the arm 110, however, tends to change slightly the alignment of forces between the backing rolls 10S and 109 and the press roll 101 and the resilient mounting for the centering pin 103 compensates automatically for the slight shifting in the position of the roll 101 relative to the positions of the rolls 108 and 109. It will be appreciated that the centering pin 103 is locked to the bearing housing 102, so that the roll 101 will be retained in position, during removal of the blanket B-l, or similar major adjustments in the parts here involved.

Referring now to FIGURES 3 and 5, it will be seen that the arms 110 and 110 are mounted at one end on a fixed pivot indicated generally at 120. The extremities 121 and 121 of the arms and 110 are formed into sleeves which, in turn, receive opposite extremities 122 and 122' of a pivot pin 123. The sleeve 121 is secured to the pin extremity 122 by a washer 124 clamped thereagainst by a lock nut 125; and the corresponding elements indicated in primed reference numerals are employed to retain the sleeve 121' to the opposite end of the pin 123. A recessed central portion 123a of the pin 123 is rotatably received in a fixed sleeve 126 formed at the bottom of a depending frame element 127 secured to the bottom of a main box frame 128 (FIGURE 3) for the nip loading device. The main box frame 128 is suitably secured to a fixed structure such as the floor of a building (not shown). The pin 123 rotates in the sleeve 126 and is also permitted limited tilting movement so that the rollers 108 and 109 may follow the contour of the press roll or cylinder 101.

The arms 110 and 110 are thus pivotally mounted about the axis of the pin 123, which is generally parallel to the line of the nip N-2. The nip N-2 is theoretically presumed to define a line of contact between the rolls 100 and 101 extending laterally of the instant device and lying in the same plane with the axes of the rolls 100 and 101, notwithstanding the fact that the rolls 100 and 101 are actually spaced apart the small distance S.

In FIGURE 3 it will be noted that the bearing housing 109a at the right hand extremity of the arm 110 mounts a pivot pin 130. As shown in FIGURE 4, pivot pins 130 and 130' are mounted at opposite ends at the top of the bearing housings 109a and 109a. The pivot pin 130 is received at its opposite ends by a bifurcated pivot sleeve 131 which, in turn, is locked by a threaded bolt 132 to one extremity 133 of a yoke 134 extending across the top of the I011 109. A similar mounting is provided at the opposite end of yoke 134 with comparable parts indicated by the primed reference numerals. The pivot pins 130 and 130' are thus axially aligned along an axis that is also parallel to the line ofthe nip N2, but the pivot pins 130 and 130 move with the arms 110 and 110'.

The central portion of the yoke 134 is connected through a pivot pin 135 to an upwardly extending thrust rod 136 which in turn, is connected to a diaphragm assembly indicated generally at 137. The diaphragm assembly 137 and thrust rod 136 are actually protected by a housing 138 indicated in FIGURE 3, but omitted from FIGURES 4 and 5. The housing 138 extends downwardly from a top frame element 128a and the diaphragm assembly 137 is secured to the top frame element 128a and acts against the frame element 128a to raise and lower the yoke 134. It will be appreciated that the pivot pin 135 interconnecting the yoke and thrust rod 136 is adapted to permit limited tilting of the yoke 134 about an axis extending longitudinally in the direction of travel of the blanket.

The diaphragm assembly 137 comprises a dish-shaped top member 139 secured to the frame element 12811, a flexible diaphragm element 140 peripherally clamped to the dish-shaped member 139 by an annular clamp 141, and the thrust rod 136 having an upper flange 136a secured to the flexible diaphragm element 140 by a disksnaped clamp 13612. A plurality of air hoses indicated at 142 are carried by the frame 128 and each supplies air to a separate diaphragm assembly 137 (as indicated diagrammatically at 142a). The air pressure in the diaphragm 137 is controlled so that the desired amount of force is applied through the rolls 108 and 109 to the portion of the press roll 101 engaged thereby.

As indicated in FIGURES 4 and 5, the top frame element 128a mounts depending frame members 128b and 128s on either side of the diaphragm 137 and these dependingframe members 12819 and 128s carry pivot pins 143 and 143', respectively, which pivotally receive the extremities 144 and 144 of a generally Y-shaped lever 145. As indicated in FIGURE 5, only the extremities of the two arms 144 and 144' of the lever 145 are shown. As shown in FIGURE 3, the arms 144 and 144' merge to form the stem 146 of the Y-shaped lever 145 and before the arms 144 and 144' merge there is mounted a pivot pin 147 extending therebetween and pivotally received by the thrust rod 136. The lever stem 146 is provided with a foot 148 that is received in a saddle 149 mounted for vertical adjustment. The position of the saddle 149 acting through the lever 145 thus limits the downward movement of the backing rollers 108 and 109 and the portion of the press roll 101 backed thereby. The position of the saddle 149 determines the minimum amount of space S between the nip-defining surfaces 160a and 101a. In the operation of the instant device, suflicient pressure may be applied through the diaphragm 137 to maintain the space S at the desired distance in spite of load resisting forces which may be created in the traveling blanket B-l; but variations in the pressure applied to the diaphragm 137 will not cause a decrease in the space beyond the predetermined setting which is controlled by the actual position of the adjustable saddle 149. Also, it will be noted that the rounded surface of the lever foot 148 engaging the saddle 149 permits the free adjustment of the assembly at such pivot points as the pivot pin and the pivot pins 130 and 130.

The saddle or stop pad 149 is mounted for vertical adjustment by axial movement of a stop screw 150 which, in turn, is driven by a worm box 151 in a manner well known per se. The worm box 151 comprises a worm mounted for rotation on a shaft 152 driving 'a worm gear which is in the form of a sleeve with its interior threadedly engaging the stop screw 150 for relative axial movement. The Worm and worm gear are well known structures which do not require further description herein, but it is sufi'icient to note that rotation of the shaft 152 results in axial movement of the stop screw 150. Such rotation may be effected merely by the use of a flexible shaft (not shown) connected at a coupling 153, or it may be accomplished by the use of an air clutch indicated generally at 154. The use of a flexible shaft connected to the coupling 153 is a well known expedient and the terminal end of the flexible shaft is mounted at a control panel whereat it is connected to a counter for indicating the number of revolutions of the shaft 152 and thus the ultimate position of the saddle or stop pad 149. The air clutch 154 is also a well known structure.

In this particular air clutch structure 154 a shaft 155 is rotated in either direction by an appropriate air motor (not shown). The shaft 155 is mounted on bearings 156 (FIGURES 4 and 5) and 157 (FIGURE 4 only). Also it will be noted that a coupling 158 shown in FIGURE 4 is omitted from FIGURE 5. The shaft 155 mounts a gear 159 which meshes with another gear 160 connected through the shaft 161 to the air clutch expandable member 162. Air is fed selectively through the shaft 161 (for example, through a connection 163 of FIGURE 4) and 'into the expandable member 162 which engages the clutch 154 by expanding against an annular member 165 corotatably mounted on the worm shaft 152. By engaging the clutch 154 in the usual manner rotation of the worm is effected and movement of the stop screw 150 results. As mentioned, this type of drive mechanism is well understood in the art and need not be described in further detail herein, because it does not form a part of the instant invention. An aspect of the instant invention resides generally in means for axially moving the stop screw 150 to accomplish the desired adjustment. Whatever movement of the worm shaft 152 does take place can be recorded by measuring revolutions thereof and this record may be used to determine the exact thickness S at the nip N2.

Referring now to FIGURES 7 and 8, it will be seen that a different embodiment of the invention is shown, indicated generally by the reference numeral 200. In this embodiment 200, elements comparable to those already shown in connection with FIGURES 3 through 6 are given a comparable reference numeral in the 200 series. Thus, it will be seen that there is a nip N-3 defined between a lower nipdefining surface 200a and an upper nip-defining surface 201a formed by a roll 201 of relatively small diameter. A rubber blanket B2 is received by the nip N-3 with -a paper Web W-3. A semi-cylindrical housing 270 receives a limited portion of the roll 201 comparable in lateral dimension to the portion of the roll 101 backed by the rollers 108 and 109 previously described. The roll 201 is clamped in the semi-cylindrical housing 270 by a shoe 271 bolted thereto so that the roll 201 is held against rotation and will not slip out of the semi-cylindrical housing 270 if support from beneath (such as the blanket 8-2) is removed.

As indicated, the semi-cylindrical housing 270 forms a bridge between spaced arms 210 and 210' (not shown) which, in turn, are mounted pivotally at one end on a pivot pin 223 comparable in structure to the pin 123 already described. At the other end of the arm 210 there is a pivot pin 230 connected to one side of a yoke 234. The yoke 234 is mounted for limited tilting movement on a pivot pin 235 connected to the lower end of a thrust rod 236. It will be appreciated that the opposite arm 210' is symmetrical to the arm 210 and mounts corresponding parts so that the pivot 230 corresponds to the pivot pin 1'30 already described; the yoke 234 corresponds to the yoke 134 already described and the pivot pin 235 corresponds to the pivot pin 135 already described.

It should be mentioned that, during operation with a suitably lubricated rubber blanket B-1 the roll 101 will cease to rotate. The roll 201 is, of course, held against rotation so lubrication thereof is required. As shown in FIGURE 8, the roll 201 comprises a shell 273 having a myriad of minute perforations therein. This shell 273 is securely mounted on a hollow tubular member 274 which forms the body of the roll 201. The hollow tubular member 274 is provided with a plurality of laterally spaced circurnierentially aligned grooves 275, 276, 277, 278, 279, etc. The grooves 275, 276, etc. communicate with the fine perforations of the outer shell 273 so that fluid may flow therefrom against the blanket B2 and lubricate the movement of the blanket B-2 past the roll 201. Lubricating fluid in the form of water or the like from a suitable source, shown diagrammatically at P flows through a valve V and into any one of a number of laterally aligned circumferentially spaced conduits 280, 281, 282, etc. As will be appreciated, valve means V are provided individually for each of the conduits 280, 281, 282 so that flow of fluid in each may be controlled independently. Each conduit communicates with a groove; and as here shown the conduit 282 communicates with the groove 27S and the conduit 281 communicates with the groove 276. In this way, lubrication at selected places in the roll 201 may be accomplished.

It will be seen that in each of the embodiments of the instant invention the use of cylindrical nip rolls (101 and 201) is permitted while providing for the equipment of crowning. This is particularly advantageous since it avoids the slippage due to differences in the peripheral speeds which are caused by diflerences in diameter along the length of a crowned roll. In the instant invention it is not necessary to change the crown of one or both rolls each time a change of nip loading is required. Even though the nip roll 101 or 201 is itself deflected, the short backing elements (such as the rolls 108 and 109) used in this arrangement may be straight, or cylindrical rather than crowned, since over the relatively short length of each backing roll set, the deflection curve does not depart practically from a straight line. The difierent positions allowed for the individual stop means for each backing roll set permits effective crowning, but the resilient loading means serve to avoid breakage of the equipment during an accident wherein excessive material may pass through the nip at a localized point. Actually, the instant device may be operated without the stop means functioning, merely by the selective loading of the individual diaphragm assemblies 137. On the other hand, with the stop means functioning the diaphragm means 137 may be employed to so load the nip at localized areas that the nip dimensions are maintained at very close tolerances.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

I claim as my invention:

1. Apparatus comprising a first cylinder, a second cylinv der defining therewith a nip for pressing a traveling flexible element passing therethrough, a plurality of laterally spaced members swingably mounted about an axis parallel to the nip, opposed rollers carried by each of said members for loading the first cylinder against the second cylinder at the nip, a separate fluid pressure actuated means connected to each of said members for resiliently urging said first cylinder toward said second cylinder, a separate stop for each fluid pressure actuated means limiting movement of said first cylinder toward said second cylinder, and independent means for adjusting the position of each stop relative to the fluid pressure actuated means associated therewith.

2. Apparatus comprising a first cylinder, a second cylinder defin ng therewith a nip for pressing a traveling flexible element passing therethrough, a plurality of laterally spaced members swingably mounted about an axis parallel to the nip, opposed rollers carried by each of said members for loading the first cylinder against the second cylinder at the nip, a yoke pivotally connected to each member about another axis parallel to said nip and a separate fluid pressure actuated means pivotally connected to each of said yokes about an axis extending longitudinally of the direction of travel of said flexible element.

3. Apparatus comprising a first cylinder, first bearing means rotatably mounting said first cylinder, a second cylinder defining with the first cylinder a nip for pressing a traveling flexible element passing therethrough, fixed bearing means rotatably mounting the second cylinder, a plurality of members spaced across the width of the nip, fixed pivots mounting each of said members at one end thereof for swinging movement about an axis parallel to the nip, movable pivots carried at the opposite end of each of said members, a yoke connected to each of said members by said movable pivots, a separate fluid pressure actuated means pivotally connected to each of said yokes about an axis extending longitudinally of the direction of travel of said flexible element for swinging said members about said fixed pivots, opposed rollers rotatably carried by each of said members for loading the first cylinder against the second cylinder at the nip, pins secured to said first bearing means and carried by said members for movement of said first cylinder toward and away from said second cylinder, and resilient means interposed between said pins and said members to allow limited relative movement between said first cylinder and said members.

References Cited in the file of this patent UNITED STATES PATENTS

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