US3730080A

US3730080A - Embosser using small diameter embossing rolls

Info

Publication number: US3730080A
Application number: US00061135A
Authority: US
Inventors: J Deligt
Original assignee: Westvaco Corp
Current assignee: Westvaco Corp
Priority date: 1970-08-05
Filing date: 1970-08-05
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

Embossing apparatus includes a pair of backup rollers rotatable about parallel axes and mounted for back-and-forth movement relative to each other to form a variable width space therebetween. Associated with the backup rollers are back stops to set width of the space between the rollers. Apparatus is provided for pressing into the space between the backup rollers an unsecured, freely positionable embossing roller having a diameter larger than the width of the space. An embossing nip is formed between the embossing roller and at least one of the backup rollers.

Description

1 a a Elite States atent 1 1 1 3,73,

Deligt 1 ay 1, R973 1 EMBOSSER USING SMALL DIAMETER 2,876,734 3 1959 Nitchie ..101/23 x EMBOSSING ROLLS 3,470,816 10/1969 Piecha etal..... 101/216 1,857,166 5/1932 Speicher ..lOl/5 [75] Inventor: John Dellgt, Covmgton, Va. 2.425167 8/1947 Whitehead IOU/90 x Assigneez Westvaco C p i N Y k 3,157,] l Mosemiller... N Y 3,334,721 8/1967 Hlckerson ..lOl/l 10 X 1 1 Filcdi g- 1970 Primary Examiner-Robert E. Pulfrey Assistant Examiner-E. M. Coven [21 l App. N0" 61,135 A!t0rneyW. Allen Macontell and Richard L.

Schmalz [52] U.S.Cl ..101/23, 101/216 511 int. c1. ..B41f 11/00, B411 13/44 [57] ABSTRACT [58] Field of Search 101/5, 6, 22, 23, I

[OI/90, I 10 2 I 6, 219, 247 153, 178485 Embossmg apparatus 1ncludes a pair of backup rollers rotatable about parallel axes and mounted for back- [56] References Cited and-forth movement relative to each other to form a variable width space therebetween. Associated with UNITED STATES PATENTS the backup rollers are back stops to set width of the 2,676,537 4 1954 Kanitz ..1 11 153 Space. belween h rollers Apparatus is provided for 2970535 2/196 Schmun A A l "ml/178 v prcssmg mto the space between the backup rollers an 3vl88948 6/1965 Fischer cl 101/178 unsecured, freely positionable embossing roller having 3,348,477 10/1967 Taylor t-i a1. ..101/23 diameter larger than the Width Oflhe p l,147.92() 7/1915 Bechmzm 101/219 bossing nip is formed between the embossing roller 3,057,292 10/1962 Larsen 101/247 and at least one of the backup rollers. 2,982,204 5/1961 Roehm 1 ..lOl/247 3,147,702 9/1964 Martin ..lOl/209 X 15 Claims, 13 Drawing Figures Patented May 1, 1973 4 Sheets-Sheet 1 IN VENTOR.

J OHN DE L1 61' 'FFq-s Patented May 1, 1973 3,730,080

4 Sheets-Sheet 2 Patented May 1, 1973 3,730,080

4 Sheets-Sheet 3 IN VLZN TOR.

JOH N DELIGT EMBOSSER USING SMALL DIAMETER EMBOSSING ROLLS BACKGROUND OF INVENTION sheet material is engraved upon the surface of a separate embossing roller. The surface characteristics of the embossing rollers therefore vary in accordance with variation in the patterns. Roller diameters also vary. The circumference of each embossing roller must be an even multiple of the linear extent, or repeat, of the embossing pattern. When embossing patterns having differing repeat lengths are to be used, the necessary result is embossing rollers of differing diameters.

It is therefore an object of this invention to provide embossing apparatus capable of utilizing different types of embossing rollers, including embossing rollers of different diameters.

It is also an object of this invention to provide embossing apparatus which will provide optimum nip loading pressures when various types of embossing rollers are used.

It is a further object of this invention to provide embossing apparatus which is uncomplicated and which will easily adapt to different types of embossing rollers with a minimum of labor and without requiring lengthy shutdown time.

SUMMARY OF THE INVENTION The present invention is directed to embossing apparatus capable of providing optimum embossing nip pressure between an embossing roller and a pair of backup rollers. The unsecured embossing roller is pressed into a space between two parallel backup rollers, the width of the space being slightly less than the diameter of the embossing roller.

The apparatus is adapted for use with unlike embossing rollers. A carriage for holding a plurality of embossing rollers is mounted adjacent the pair of backup rollers so that embossing rollers held by the carriage may be moved from the carriage and pressed between the two backup rollers. In a preferred embodiment, the backup rollers are mounted for back-and-forth move ment relative to each other and are provided with back stops which limit the distance apart which the back-up rollers may move. The backup rollers are biased so that. when the system is at rest, they move toward each other, toward a central locus directly above an elevating apparatus. The carriage for holding the embossing rollers is movable back-and-forth relative to the elevating apparatus. The carriage may therefore by positioned so that a selected one of the embossing rollers is located adjacent the elevating apparatus and the backup rollers. The elevating apparatus is activated to lift the selected embossing roller from the carriage and then press it between the two backup rollers. As the selected embossing roller is pressed between the two backup rollers, the backup rollers move apart until they are pressed firmly against their back stops. The back stops are preferably set so that the maximum distance which the backup rollers can move apart is only slightly less than the diameter of the selected embossing roller.

The selected embossing roller may thus lay as deep as possible between the backup rollers without being pressed through dead center. It is, of course, understood that the back stops may be set to establish a distance between the backup rollers which is substantially less than the diameter of the selected embossing roller, if such an arrangement is desired.

Under the above conditions, an embossing nip is formed between the embossing rollers and at least one of the backup rollers. Due to the geometry of the system, relatively large embossing nip loads may be obtained from a relatively small load produced by the elevating apparatus.

To change embossing rollers, the elevating device is retracted so that the selected embossing roller is replaced in the carriage. The position of the carriage is then shifted to locate another roller adjacent the elevating device for subsequent use. The stop mechanism for limiting the distance the backup rollers may move apart is adjusted so that the space attainable between the backup rollers is set in accordance with the character of the embossing roller selected for use.

When the diameters of the embossing rollers available for use are unequal, the back-stop mechanism is adjustable so that the spacing between the backup rollers will be appropriate for the diameter of the particular embossing roller selected for use. It should be understood that characteristics of the embossing rollers other than diameter influence the setting of the backup rollers. For example, roller firmness or the character of the design ingraved into its surface could influence the optimum backup roll setting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially broken away front elevational view of a preferred embodiment of this invention;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a partially broken away end elevational view of certain elements of the embodiment shown in FIG. 1 with an embossing roller in operative position;

FIG. 4 is an end elevational view of certain elements of the embodiment shown in FIG. 1 with the embossing rollers in inoperative position;

FIG. 5 is a broken away view showing details of certain elements illustrated in FIG. 3;

FIG. 6 is a cross-sectional view taken along lines 6- 6 of FIG. 5;

FIG. 7 is a detailed view of apparatus shown in FIG. 1

FIG. 8 is a cross'sectional view taken along lines 8- 8 of FIG. 7;

FIG. 9 is a detailed view of an element illustrated in FIG. 1;

FIG. 10 is a schematic view showing a hydraulic system for giving support to an embossing roller during the embossing operation;

FIG. I 1 illustrates another embodiment of apparatus for supporting an embossing roller during the embossing operation;

FIG. 12 is a schematic diagram illustrating the relative magnitudes of the load applied to the embossing roller and the resulting embossing nip loads; and

FIG. 13 is a schematic view illustrating an alternate embodiment of this invention wherein two webs may be embossed simultaneously.

DETAILED DESCRIPTION OF THE DRAWINGS A preferred embodiment of this invention will now be described with reference to the attached drawings. As best illustrated in FIGS. 1 and 2, frame supports a pair of backup rollers consisting of a driven backup roller 12 and an idler backup roller 14.

Backup rollers

12 and 14 are preferably coated with a $41 inch thickness film of 90-95 Shore A hardness polyurethane which constitutes a resilient surface for the backup rolle'rs to force a flow of the paper web into patterned relief cavities of embossing rolls 60, 62, 64 and 66. A movable carriage means 16 for holding a plurality of unsecured embossing rollers is mounted beneath the backup rollers. Mounted beneath the carriage means 16, for cooperation with the carriage means and the backup rollers, is means 18 for rotatably supporting an embossing roller and pressing it between the backup rollers.

The carriage means 16 includes a tray 41 having side members 40 joined by a pair of connecting members 42. Extending from the sides 40 of a tray 41 are a plurality of bearing members 46 adapted to support the tray 41 from frame 10, in a substantially horizontal plane. Thrust bearing members 56 extend from sides 40 of the tray 41 for engagement with the frame 10 to prevent lateral shifting movement of the tray 41 as it is reciprocated in the substantially horizontal plane as will here-after be described.

Extending inwardly from opposite sides of the frame 10 are a pair of tracks 44 which provide support for bearing members 46 and, therefore, for the tray 41. The tracks 44 are positioned beneath the

backup rollers

12 and 14 at the midsection of the embossing apparatus. Space for the embossing roller supporting and pressing means 18 is provided below the tray means 16. Mounted beneath the side members 40 of the tray 41, for cooperation with pinions 50, are racks 48. The pinions 50 and a handwheel 52 are mounted upon a handwheel shaft 54. Rotation of the handwheel 52 rotates the pinions 50 to drive racks 48 and thereby tray means 16 along the tracks 44 in a rectilinear fashion.

The side members 40 of the carriage means 16 are substantially parallel and upstanding portions of each side member 40 forms four seats 58 for supporting four embossing rollers: 60, 62, 64 and 66. As seen in FIG. 8, the embossing rollers have mounted on the ends thereof a collar 65 including an annular groove 67. The collars 65 at opposite ends of a particular embossing rollers are adapted to rest in opposing seats 58 in the side members 40 so that the annular grooves 67 will receive the upstanding edges of the portions of the side .members 40 which form the seats 58. Mounted upon inwardly facing surfaces on each of the opposing side members 40, adjacent each side ofeach ofthe seats 58, is a cam member 148 which forms opposing cam surfaces 160. The cam members cooperate with the means 18 to provide an interlock for correctly positioning the carriage means 16 when an embossing roller is to be put in use and for preventing movement of the carriage means 16 when the machine is in operation.

ln the preferred embodiment herein described, the embossing rollers are of a relatively small diameter. This causes them to be somewhat flexible in comparison to the backup rollers. Moreover, the embossing rollers lack any connection with the frame 10 by rigid support structure and are freely positionable relative thereto. Accordingly, during the embossing operation, the embossing rollers require cooperative confining and support structure along substantially their entire length to avoid undesirable shifting and deformation thereof. That is, it is desirable to confine support the embossing roller along its entire length so that its longitudinal axes will either lie in a straight line or so as to approximate a straight line.

The means 18 provides continuous support for the embossing roller during the embossing operation. It also serves to lift a selected embossing roller for the carriage means 16 to the backup rollers and, subsequently, replace the embossing roller in the carriage means 16. The means 18 consists of two cooperating assemblies, a loader 68 and a jack 70. The loader 68 provides the correct loading of the embossing roller against the

backup rollers

12 and 14. The jack serves to advance and retract the loader. The loader 68 comprises a rigid hollow housing 72 containing a plurality of hydraulic piston and cylinder elements 75. Piston shafts 74 extend from each of the piston and cylinder elements 75 to support a cradle 76. Cradle 76 includes four upstanding members 80 between which are mounted three embossing roller supporting discs 78, the roller supporting discs being rotatably mounted on axles 82 which extend between each two adjacent upstanding members, as best illustrated in FIG. 9. The center roll supporting disc 78 is rotatably mounted on an axle 82 which is offset in one direction from the center of the cradle 76. Discs 78 on each side of the center disc are rotatably mounted upon axes 82 which have their longitudinal axes in alignment with each other and are offset to the opposite side of the cradle. The offset discs form a seat for rotatably supporting an embossing roller. Line 77 is indicative of the longitudinal axes of an embossing roller supported by the cradle 76 and it closely corresponds to the longitudinal axis of the cradle 76. A plurality of cradles 76 are arranged in a straight line along the housing 72 so that an elongated, continuous seat configuration is formed which will support an embossing roller along substantially its entire length. Stabilizing pins 84 extend from the housing 72 to each of the cradles to prohibit rotation of the cradles about the longitudinal axes of the shafts 74.

It is also desirable to provide a substantially uniform pressure along the length of the embossing roller so that a paper web or the like engaged in an embossing nip formed between the embossing roller and one of the backup rollers is subjected to a substantially even embossing pressure across its width. It will be observed that the hydraulic piston and cylinder element 75 are constructed to maintain the longitudinal axis of an embossing roller substantially straight during embossing operation but, while maintaining the longitudinal axes substantially straight, .a small, controlled degree of deflection of the embossing roller is permitted. Control of the deflection is effected by the piston and cylinder elements 75 in conjunction with the hydraulic system shown in FIG. 10. The piston and cylinder elements 75 are connected to each other, in parallel, by a system of fluid conduits which contain a constant volume of hydraulic fluid. The system operates in this manner.

When, during the embossing operation, conditions are such that an uneven force is applied along the length of the embossing roller, that portion of the roller to which the greater force is applied will tend to deflect in one direction while other portions of the embossing roller will tend to deflect in the other direction. The cradles which support a portion of the roller subject to the tendency to deflect is permitted by its hydraulic support to yield slightly. This yielding causes pistons 85 to move within adjacent cylinders 75 so as to increase the volume of upper chambers 81 of some cylinders and decrease the volume lower chambers 83 of other cylinders. The fluid displaced from the lower chambers 83 of cylinders in which the piston 85 move downwardly is forced out of those cylinders 75 and fills lower chambers 83 of the other cylinders 55. Fluid removed from the upper chambers 81 of the aforesaid other cylinders as the upper chambers 81 decrease in volume due to increase in the volume of lower chambers 83 thereof, is forced out and travels through conduits 79 to upper chambers 81 of the cylinders 75 in which pistons 81 have moved downwardly. For example, if an embossing roller deflects downward slightly in its central portion during an embossing operation, the center cradles 76 will move downward to accommodate the deflection while the cradles adjacent the ends of loader 68 will rise slightly so as to more nearly conform to the shape which the embossing roiler seeks. All cradles exert sub stantially the same force upon the embossing roller and uniform embossing nip pressure is applied along the entire length of the embossing roller. It will be understood that all of the pistons and cylinders interact with each other so that the sum of the volumes of lower chambers 83 is always constant and the sum of the volumes of upper chambers 81 of the cylinders 75 is always constant.

Also illustrated in FIG. is connection block 180 into which a number of conduits 79 connect and to which a pressure switch 182 is connected. The pressure switch 182 responds to the sum of the pressures in all of the lower chambers 83 of all of'the cylinders 75 to influence the operation of jack motor 96, in a manner hereafter described.

An alternate embodiment of apparatus for supporting the cradles 76 is illustrated in FIG. 11, wherein like numerals are used to designate like parts. In the apparatus of H6. 11, the cradles 76 are supported upon shafts 84 which extend downwardly through housing 72. Mounted upon each of the shafts 184 is a member 186 for retaining spring 188. The springs 188 apply a constant upward bias to the cradles 76. In this embodiment. there is no interaction between the individual cradle supports and more variation is thereby permitted in the force applied by the individual cradles to an embossing roller during embossing operation. However, the supporting apparatus of this embodiment gives good embossing results and, due to its simplicity, is preferred in applications wherein extremely careful control of the embossing nip pressure is not required.

lt' will of course be obvious that other systems for supporting the cradles 76 may be used. It will be acceptable, in some operations, to mount the cradles rigidly to the housing 72. With the latter construction, the tendency to develop an uneven loading profile along the length of the embossing roller is greater than that occurring in the embodiments described in connection with FIGS. 10 and H1. The differences in the force applied to the embossing roller by the individual cradles 76 is, however, related to the degree of load control required in particular embossing situations and not the overall operability of the embossing apparatus forming the subject of this invention.

Jack supports loader 68 and drives the loader toward and away from the

backup rollers

12 and 14. Mounted upon base 86 are two screw jacks 88, each having an elongated threaded screw 90 extending upwardly therefrom. Mounted for cooperation with the screws 96 are a pair of threaded nuts 92. The nuts 92 are secured within cylindrical members 94 which are fixed to the base of housing 72. Drive means for the screw jacks 88 is also mounted upon the base 86 and includes a reversible motor 96 which drives a cross shaft 98 through a connecting drive chain 100. The cross shaft 98 supports a drive chain sprocket 102 for cooperation with the drive chain MN) and is operatively connected, by the means 105, to the input shaft 104 of each of the screw jacks 88. The cross shaft 958 is supported near its midsection by a bearing means 106. Members 93 serve as protective shilds for screws 90.

The

backup rollers

12 and 14 are each rotatably mounted between the ends of a pair of arm members 20. The other ends of the arm members 20 are pivotedly mounted upon shafts 24 secured within the frame 10. One pair of the arms 20 is positioned in the embossing apparatus for supporting the backup roller 12 and the other pair of arms 20 is similarly positioned for supporting the backup roller 14, as is best seen in FIGS. 1, 3 and 4. The backup rollers are thus movable toward and away from each other. The amount of separation which may be obtained between the backup rollers is controlled by a stop means 28.

The stop means 28 comprises four identical turrets 30. Each of the four turrets is positioned to limit pivotal movement of one of the four arms which support the two backup rollers. Each of the turrets comprises a block 32 rotatably mounted within the frame 10, between the

side portions

11 and 13, upon a shaft 15. The turrets 30 are releasably held in a selected angular position by retaining means 17 which may comprise a stop pin 19 arranged for cooperation with a'series of detents 21 in the turrets 30. Each of the turrets includes four

stop elements

34, 36, 38 and 40 which extend from the block 32. The four stop elements 34 (one of each of the four turrets 30) form a set of cooperating stop elements 34. Similarly, the four stop elements designated 36, 38 and 40 form sets of cooperating stop elements. Each set of stop elements corresponds to a particular type of embossing roller and permits a predetermined amount of pivotal movement of supporting arm pairs 20 about their respective shafts 24. That is, each stop element set is positionable to limit movement of the arm pairs 20 at a different angular disposition.

The number of stop element sets utilized equals the number of different types of embossing rollers to be used. In the preferred embodiment, there are four sets of stop elements corresponding to four different types of embossing rollers. Stop element sets 34, 36, 38 and 40 are designed for use with

embossing rollers

60, 62, 64 and 66, respectively. If the embossing rollers held by tray 41 each have a different diameter, each set of stop elements will correspond to a roller of predetermined diameter and will be calibrated to establish a maximum separation between the

backup rollers

12 and 14 of slightly less than the predetermined diameter.

In FIG..5, the stop elements are shown having a threaded base which is screwed into a corresponding threaded opening in the block 32. This arrangement permits the stop elements to be adjusted to enable more than four types of embossing rollers to be used with the embossing apparatus without making it necessary to change the turrets 30. The'stop elements are held in a predetermined adjustment by means 39 which may comprise a set screw. It will be recognized that the turrets may include more or less than four stop elements and that the rack 48 may be designed to accommodate more than four or less seats 58 along each of the side members 40 of the tray 41.

As the loader means 68 is being raised and lowered by the jack 70, it is necessary to stabilize the loader means so that it follows a straight upward path and does not shift from side to side. To stabilize the loader 68, guide means 150 is provided. The guide means 150 ineludes a pair of upper guide members 152 and a pair of lower guide members 154. A space is provided between the upper and lower guide members to accommodate the carriage means 16, as shown in FIGS. 7 and 8. Mounted at each end of the housing 72 is a slide 156 which includes a central projection 158. The central projection 158 is slideably engagable between both the upper guide members 152 and the lower guide members 154. When the loader means 68 is in its raised position for pressing an embossing roller between the

backup rollers

12 and 14, the projection 158 is engaged between both the upper and lower guide members. When the loader means 68 is in its lowermost position, the projection 158 is engaged between the lower guide members 154 only.

The lateral distance between cams 148 on the carriage means 16 equals substantially the width of the projection 158. Therefore, as the loader 68 is raised by the jack 70, the projection 158 passes between the pairs of cam members 148 which flank the seats supporting the embossing roller which is selected to be.

lifted between the backup rollers. The interposition of the projection 158 between the set of cam members prevents movement of the tray 41 while the loader 68 is in a raised position. Tapering cam surfaces 160 enable the projection 158 to interlock with the tray 41 even if the tray has not been positioned in exactly the proper position beneath the backup rollers. The camming action resulting from cooperation between the tapering cam surfaces 160 and the projection 158 serves to properly align the tray 41 before an embossing roller is lifted.

To conduct the continuous paper web through the embossing nip between a selected embossing roller and the backup rollers, guide

rollers

200 and 202 are provided. The paper web 25 travels in the direction indicated by the arrow and is drawn over the guide member 200, through the embossing nip formed by the selected embossing roller and the backup roller 14 and then over guide member 202. An alternate embodiment wherein two paper webs are simultaneously drawn through a pair of embossing nips formed by the selected embossing roller and the two backup rollers is illustrated in FIG. 13.

Guide rollers

204 and 202 guide a web of paper through an embossing nip 206 formed by a selected embossing roller and the backup roller 14. A second web 25 may be embossed simultaneously with the first by drawing it through embossing nip 210 which is formed by the selected embossing roller 60 and the backup roller 12. The second web is conducted through embossing nip 210 by guide rollers 208 an 200.

The driving means for the backup rollers and the I selected embossing roller comprises a drive wheel 212, driven by an external driving mechanism, not shown. From the drive wheel 212, torque is transmitted through the drive shaft 214, drive gear 216 and driven gear 218 to rotate the driven backup roller 12. Fric-' tional engagement between the driven backup roller 12, the selected embossing roller 60 and the backup roller 14 produces rotation of the embossing roller and the backup roller 14.

The operational steps of the above described embossing apparatus will now be described.

The rest position of the embossing apparatus is shown in FIG. 4. When the apparatus is to be activated, an operator selects one of the several embossing rollers by use of the handwheel 52. The handwheel 52 drives the pinions 50 which, through the rack 48, advance tray means 16 until the indicia 161 beneath the selected embossing roller has been brought into registration with cooperating indicia, not shown, on the housing 10. In the preferred embodiment shown, the embossing roller 60 has been selected. When the indicia 161 beneath the roller has been aligned, the motor 96 is activated to drive cross shaft 98 and thereby operate the screw jack 88 to turn the screws 90. As the screws 90 turn they cooperate with the nuts 92 to raise the cylindrical members 94 and thereby the entire loader means 68. As the loader means 68 is being raised, roller supporting discs 78 engage the embossing roller 60 and lift it from its seat 58 in the tray 41 and raise it to a position adjacent the surfaces of the

backup rollers

12 and 14. Continued upward movement presses the embossing roller 60 between the backup rollers and drives them apart. The backup rollers swing away from each other on their respective arms 20, each of these arms being free to pivot about itsrespective shaft 24. Upward movement of the embossing roller is continued until the jack means is deenergized by pressure the switch 182 in responseto a predetermined pressure build-up in the closed hydraulic system of.

FIG. 10. The pressure switch is calibrated to cut off the jack motor 96 at the predetermined pressure which occurs when the desired embossing nip load has been obtained. Safety switch means 220, shown in FIG. 2, will deenergize the jack motor 96 in response to a predetermined downward movement of the cradle 76 relative to the housing 72 to avoid damage to the embossing roller if the pressure switch 182 should malfunction. If thealtemate embodiment illustrated in FIG. 11 is used for supporting the cradles 76, the pressure switch 182 is, of course, dispensed with. Under this circumstance, the switch 220 serves as the main deenergizing switch rather than as a safety switch and it is calibrated, in accordance with the spring constant of the spring 188, to deenergize the jack motor 96 in response to the predetermined movement of the cradle 76 toward the housing 72 which corresponds to the desired embossing nip load.

The effect of pressing an embossing roller between two backup rollers in the manner described above is illustrated by F 1G. 12. When the loader means 68 presses an embossing roller between the

backup rollers

12 and 14 with a force of magnitude a, the reaction forces designated r," and r produce embossing nip loads between the embossing roller and the backup rollers which are substantially greater than the upward load applied by the loader means 68.

After the embossing roller is properly seated between the

backup rollers

12 and 14, an input drive, not shown, turns the drive wheel 212 and ultimately the backup roller 12. Frictional engagement between the embossing roller 60 and the backup rollers causes backup roller 14 and embossing roller 60 to cooperate and draw the paper web 25 through the embossing nip. The paper web 25 is embossing as it passes between the selected embossing roller 60 and the backup roller 14. In the illustration of FIG. 2, the paper web 25 is ad vancing in the direction of the arrow and the two backup rollers are rotating clockwise and the embossing roller counterclockwise.

When the embossing operation with the selected embossing roller 60 is complete, the input drive to the backup rollers and the embossing roller is terminated. Rotation of the backup rollers and the embossing roller may be stopped before the embosser is retracted from between the backup rollers. Any well known breaking device, not shown, may be used. Thereafter, the jack motor 96 is energized and driven in the reverse direction to lower the loader means 68. As the loader means is lowered, the selected embossing roller 60 is moved from between the

backup rollers

12 and 14. The arms supporting the

backup rollers

12 and 14 pivot about their respective shafts 24 so that the

backup rollers

12 and 14 advance toward each other until their surfaces engage or until the advancement toward each other is terminated by a stop means, not shown. Lowering of the loader means 68 is continued until the embossing roller 60 has been replaced in its seat 58, the projection 158 has been drawn from-between cams 148 and the upper portion of the slide 156 has passed beneath the tray 41. The jack motor 96 is then de'energized. The carriage means 16 is then moveable to permit selection of another embossing roller. The continu' ous paper web 25 may be retained between the

backup rollers

12 and 14 for further embossing when the machine is reactivated or, if different paper stock is desired, the web 25 is withdrawn and another web is fed through the embossing apparatus.

It is to be understood that the foregoing is a description of a preferred embodiment and that the invention is not limited to the specific apparatus shown and described. Therefore, changes may be made in the described preferred embodiment without departing from the scope of the invention. I

I claim:

1. Embossing apparatus comprising:

a. means for holding a plurality of embossing rollers having various diameters;

b. a pair of rotatably mounted backup rollers adapted for movement toward and away from each other;

c. variable stop means for limiting movement of said backup rollers away from each other, said variable stop means being capable of selectively limiting the maximum distance attainable between said backup rollers to a surface separation distance of less than the diameter of a selected one of such embossing rollers;

. means for placing a select one of such embossing rollers in a predetermined position of alignment with said backup rollers; and

e. means to engage and rotatably support said select one of such embossing rollers at said predetermined position for advancing such one embossing roller from said holding means and pressing it between said backup rollers with sufficient force to move said backup rollers apart and form an embossing nip between such embossing roller and at least one of said backup rollers.

2. Embossing apparatus according to claim 1 wherein said stop means comprises turret means having a plurality of sets of stop elements for arresting motion of said backup rollers, each one of said sets being calibrated for use with an embossing roller of predetermined diameter.

3. Embossing apparatus according to claim 2 wherein each of said sets of stop elements is adapted to limit the maximum distance attainable between said backup rollers to a linear dimension less than the diameter of the embossing roller for which the respective stop member set is calibrated.

4. Embossing apparatus according to claim 1 wherein said means for holding a plurality of embossing rollers comprises a movable carriage.

5. Embossing apparatus according to claim 4 wherein said placing means comprises means for moving said carriage relative to said backup rollers to locate said selected one of such embossing rollers in said predetermined position for advancement by said engaging means.

6. Embossing apparatus according to claim 5 wherein said engaging means provides support along substantially the entire length of such selected embossing roller.

7. Embossing apparatus according to claim 1 wherein said engaging means provides support along substantially the entire length of such selected embossing roller.

8. Embossing apparatus according to claim 1 wherein such embossing rollers are of substantially smaller diameter than the diameter of said back-up rollers.

9. Embossing apparatus comprising:

a. a movable carriage for holding a plurality of embossing rollers having various diameters;

b. a pair of rotatably mounted backup rollers mounted for movement toward and away from each other, said backup rollers being of substantially larger diameter than the diameter of such embossing rollers;

c. turret means having plurality of sets of stop elements, each of said sets of stop elements being calibrated for use with an embossing roller of predetermined diameter to limit the maximum distance attainable between said backup rollers to a linear dimension slightly smaller in magnitude than the diameter of the embossing roller for which the respective stop member set is calibrated;

. means for moving said carriage relative to said backup rollers to locate a selected one of such embossing rollers in a predetermined position for subsequent advancement to cooperative relationship with said backup rollers; and

e. means adapted to rotatably support a selected one of such embossing rollers along substantially its entire length for advancing such one embossing roller from said carriage and pressing it between said backup rollers with sufficient force to move said backup rollers apartand form an embossing nip'between such embossing roller and at least one of said backup rollers.

10. Embossing apparatus comprising:

a. structural'framing means;

b. a pair of substantially cylindrical backup rollers having substantially parallel axes extending between journal support means at opposite respective ends thereof;

c. journal control means having said journal support means secured thereto, said journal control means being movably secured to said framing means for sustaining said rolleraxis parallelism through reversible movements along respective paths that extend from a position of backup roller cylinder surface element tangency;

d. substantially cylindrical embossing roller means;

e. force applicator means disposed substantially parallel to said backup roller axes for exerting a force vector substantially tangentially between i said backup rollers, said force applicator means having embossing roller engaging means along the length thereof, said engaging means allowing free rotation of said embossing roller, said engaging means being selectively movable between operative and inoperative positions, said operative position comprising a compressive force disposition of said embossing roller means between said engaging means and said backup rollers, said inoperative position being signified by the absence of said compressive force disposition, said embossing roller means being positionally confined in said operative position and structurally unconfined in said inoperative position;

f. abutment means secured to said framing means for engaging said journal control means to limit divergent displacement of said backup rollers to a magnitude between said backup roller axes of less than web through a second nip between said embossing roller and the other of said backup rollers. 12. Embossing apparatus according to claim 10 further comprising:

a. movable carriage means having individual stowage positions for a plurality of embossing roller means; b. said embossing roller engaging means comprising roller placement means secured thereto; and

c. said carriage means being disposed relative to said roller placement means and said backup rollers to align a particular stowage position with said roller placement means for translation thereby into engagement with said backup rollers.

13. Embossing apparatus according to claim 12 wherein said roller placement means comprises selectively reciprocable mounting means, said carriage means being disposed to align a particular stowage position within the reciprocation path for said placement means.

14. Embossing apparatus according to claim 12 wherein various embossing roller means diameters may be accommodated by said plurality of stowage positions, said-abutment means comprising a plurality of adjustable stop means respectively secured to a plurality of indexing turret stations, each of said index stations having said respective stop means adjusted to limit the cylindrical surface separation distance between said backup rollers to a desired dimension less than the diameter of a select one of said various embossing roller means.

15. Embossing apparatus according to claim 14 further comprising:

a. first web guide means for directing a first web through a first nipbetween said select embossing roller means and one of said backup rollers; and b. second web guide means for directing a second web through a second nip between said select e mbossing roller means and the other of said backup rollers.

Claims

1. Embossing apparatus comprising: a. means for holding a plurality of embossing rollers having various diameters; b. a pair of rotatably mounted backup rollers adapted for movement toward and away from each other; c. variable stop means for limiting movement of said backup rollers away from each other, said variable stop means being capable of selectively limiting the maximum distance attainable between said backup rollers to a surface separation distance of less than the diameter of a selected one of such embossing rollers; d. means for placing a select one of such embossing rollers in a predetermined position of alignment with said backup rollers; and e. means to engage and rotatably support said select one of such embossing rollers at said predeterMined position for advancing such one embossing roller from said holding means and pressing it between said backup rollers with sufficient force to move said backup rollers apart and form an embossing nip between such embossing roller and at least one of said backup rollers.

9. Embossing apparatus comprising: a. a movable carriage for holding a plurality of embossing rollers having various diameters; b. a pair of rotatably mounted backup rollers mounted for movement toward and away from each other, said backup rollers being of substantially larger diameter than the diameter of such embossing rollers; c. turret means having plurality of sets of stop elements, each of said sets of stop elements being calibrated for use with an embossing roller of predetermined diameter to limit the maximum distance attainable between said backup rollers to a linear dimension slightly smaller in magnitude than the diameter of the embossing roller for which the respective stop member set is calibrated; d. means for moving said carriage relative to said backup rollers to locate a selected one of such embossing rollers in a predetermined position for subsequent advancement to cooperative relationship with said backup rollers; and e. means adapted to rotatably support a selected one of such embossing rollers along substantially its entire length for advancing such one embossing roller from said carriage and pressing it between said backup rollers with sufficient force to move said backup rollers apart and form an embossing nip between such embossing roller and at least one of said backup rollers.

10. Embossing apparatus comprising: a. structural framing means; b. a pair of substantially cylindrical backup rollers having substantially parallel axes extending between journal support means at opposite respective ends thereof; c. journal control means having said journal support means secured thereto, said journal control means being movably secured to said framing means for sustaining said roller axis parallelism through reversible movements along respective paths that extend from a position of backup roller cylinder surface element tangency; d. substantially cylindrical embossing roller means; e. force applicator means disposed substantially parallel to said backup roller axes for exerting a force vector substantially tangentially between said backup rollers, said force applicator means having embossing roller engaging means along the length thereof, said engaging means allowing free rotation of said embossing roller, said engaging means being selectively movable between operative and inoperative positions, said operative position comprising a compressive force disposition of said embossing roller means between said engaging means and said backup rollers, said inoperative position being signified by the absence of said compressive force disposition, said embossing roller means being positionally confined in said operative position and structurally unconfined in said inoperative position; f. abutment means secured to said framing means for engaging said journal control means to limit divergent displacement of said backup rollers to a magnitude between said backup roller axes of less than the sum of the radii of said backup rollers and the diameter of said embossing roller means when said embossing roller means is in said operative position.

11. Embossing apparatus according to claim 10 further comprising: a. first web guide means for directing a first web through a first nip between said embossing roller and one of said backup rollers; and b. second web guide means for directing a second web through a second nip between said embossing roller and the other of said backup rollers.

12. Embossing apparatus according to claim 10 further comprising: a. movable carriage means having individual stowage positions for a plurality of embossing roller means; b. said embossing roller engaging means comprising roller placement means secured thereto; and c. said carriage means being disposed relative to said roller placement means and said backup rollers to align a particular stowage position with said roller placement means for translation thereby into engagement with said backup rollers.

14. Embossing apparatus according to claim 12 wherein various embossing roller means diameters may be accommodated by said plurality of stowage positions, said abutment means comprising a plurality of adjustable stop means respectively secured to a plurality of indexing turret stations, each of said index stations having said respective stop means adjusted to limit the cylindrical surface separation distance between said backup rollers to a desired dimension less than the diameter of a select one of said various embossing roller means.

15. Embossing apparatus according to claim 14 further comprising: a. first web guide means for directing a first web through a first nip between said select embossing roller means and one of said backup rollers; and b. second web guide means for directing a second web through a second nip between said select embossing roller means and the other of said backup rollers.