Graphic Arts Film Dryer

U.S. Pat. No. 3,557,469, dated Jan. 26, 1971, issued to the present Donald C. Edgington;

U.S. Pat. No. 3,800,434, dated Apr. 2, 1974, issued to the present inventors.

The invention resides in the general field of graphic arts, and particularly a dryer for drying film. The above two identified patents relate to the general kind of film dryer concerned herein and the present invention includes improvements over the devices of those patents. This kind of dryer includes a plurality of pairs of squeegee rollers, and the film to be dried is introduced between the rollers of the pairs and then passing from one pair to the next, the rollers then squeegeeing the water from the film, air being directed against the film for assisting in the drying operation. Breakaway clips are included in association with the rollers to prevent the film from wrapping around the rollers, and to guide and direct the film in a plane passing between the rollers of the pairs. The dryer includes a motor for driving the rollers, and a motor-blower for developing an air stream and directing the air onto the film.

A main and broad object of the invention is to provide a novel graphics arts film dryer of the foregoing general character.

Another and broad object is to provide a film dryer having a novel mechanical construction greatly facilitating removal of various components and parts from the dryer, correspondingly facilitating servicing.

Another object is to provide afilm dryer having a novel arrangement having driving means for feeding film through the dryer, and driving means for developing an air current, and having the advantage that the air is drawn or blown over the driving means for cooling them, and the air picked up in the cooling step assists in drying the film.

Another object is to provide a film dryer that is unusually quiet in operation.

A more specific object is to provide a film dryer wherein the utilized in the cooling and drying steps, passes through spaces of substantial size and distribution whereby to effectively insulate the noise of operation of the device.

Another object is to provide a film dryer wherein the air utilized in cooling and drying passes through interior passages of the motors which develops the air passage, whereby to efficiently cool those motors.

A further object is to provide a film dryer having a novel construction and arrangement of spaces and chambers, wherein at one stage, air pressure of substantial magnitude is developed for effectively directing it onto the film in the drying step, and the construction of the dryer includes a special strengthening feature against air pressure, whereby to enable utilization of a simple construction.

Another object is to provide a film dryer of the foregoing character which, because of its unusual effective drying operation, can be made with fewer squeegee rollers, and thereby be more simple and less expensive for a given drying operation.

A further object is to provide a film dryer having effective squeegee roller arrangement so as to remove the greater quantity of the water as a first step in the drying operation.

Still another object is to provide a film dryer of unusually simple construction, including a novel design enabling various components and parts to be removed from the dryer as a whole, which includes such items as a drip pan, and cover, which, individually and together, tend to confine and direct the air in the area of the film to effect passage of that air along the direction of its feeding through the dryer, to increase the drying operation.

Another and more specific object is to provide, in a film dryer, novel squeegee rollers and breakaway clips, the clips preventing the film from wrapping around the squeegee rollers, wherein the clips are of novel construction and form, to facilitate removal of the clips from the rollers, and further to enable removal of the clips without disassembling any of the rollers, or components in which the rollers are incorporated.

A still further object is to provide a film dryer having a series of pairs of squeegee rollers for feeding the film through the dryer in a drying operation, wherein the successive rollers are driven at progressively increased peripheral speeds whereby to increase the feeding speed of the film as the film passes through the dryer, to prevent buckling or otherwise misshaping of the film.

In the drawings:

FIG. 1 is a perspective view of a film made according to the present invention;

FIG. 2 is a perspective view of the dryer with the cover in open position, taken from a different angle from that of FIG. 1;

FIG. 3 is a top plan view of the dryer with the cover and the top closure plates at the ends removed;

FIG. 4 is a transverse vertical sectional view of the dryer, taken at line 4--4 of FIG. 3;

FIG. 5 is a detail view of the driving gearing, taken at line 5--5 of FIG. 3, partially diagrammatic in nature;

FIG. 6 is a longitudinal vertical sectional view, somewhat diagrammatic in nature, omitting various details;

FIG. 7 is a side elevational view somewhat diagrammatic in nature, omitting details, and showing parts in exploded position;

FIG. 8 is a detail view taken at line 8--8 of FIG. 3; and

FIG. 9 is a perspective view of a fragment of an air tube utilized in the dryer.

Referring in detail to the drawings, the dryer as a whole is indicated in its entirety at 12, and includes as its main components and parts, a frame 14, a roller assembly 16, a drive motor assembly 18, a motor-blower assembly 20, a cover 22, a drip pan 24, a feed roller 25, and end top closure plates 26, 27. These components and parts are mutually separable from each other and individually removable from the dryer as a whole, as will be described in detail hereinbelow.

The dryer is generally elongated transversely, having a front or entry side 28 facing the observer in FIGS. 1 and 2, and also shown in FIGS. 3 and 4, and an opposite rear or exit side 29, these orientations corresponding with the passage of the film through the dryer.

The frame 14 may be of sheet metal pieces suitably secured together, including a base element 30 which may be generally similar to an inverted tray or pan which has an element 31 serving as a floor or bottom element to the dryer as a whole. The base includes a surrounding downturned flange 32.

The frame 14 is provided with upstanding boxes 34, 36 at the right and left sides in the orientation of FIGS. 1, 2 and 6, and a valley or cavity 37 therebetween. The box 34 defines a chamber or well 38 in which the drive motor assembly 18 is positioned, the details of which are described hereinbelow. The box 32 includes an outer wall 40, an inner wall 42, and front and rear walls 44. The inner wall 42 is provided with a notch or cut-out 46 for cooperation in mounting the roller assembly 16 as described hereinbelow, the marginal edges of this notch 48 having flanges 49 secured thereto as by spot welding, forming grooves 50 for receiving a plate of the roller assembly. The outer wall 40 is provided with apertures or holes 52 for intake of air and the floor element 31 is provided with apertures or holes 54 (FIG. 3), below which is a suitable filter 55; the apertures 54 lead to a conduit, or air transfer or tunnel 56 which as viewed in FIG. 4 is of substantial width, on the under side of the floor element. The substantial width of the conduit enables it to be relatively shallow and still provide the desired air flow capacity, this factor being of significance in the noise insulation feature and compactness of design. The air transfer or conduit 56 continues to the opposite or left end of the frame where it opens through similar apertures or holes 58 into the chamber or well 60 formed by the box 36, this box having an outer wall 62, front and rear walls 64, and an inner wall 66. The inner wall is provided with a notch or cut-out 68 for cooperation with a plate in the roller assembly 16 as referred to again hereinbelow, this inner wall also having flanges 70 secured thereto as by spot welding around the marginal edges of the notch, forming grooves 72 for directly receiving the plate mentioned in the roller assembly. The cavity 37 and the chambers 38 and 60 form what may be referred to generically as stations.

The base of the frame is provided with a plurality of legs 74 of resilient material, longer than the depth of the flanges of the base and the conduit 56, for supporting the entire weight of the dryer.

The roller assembly 16 includes a plurality of rollers 76, arranged in pairs 76a, 76b and 76c spaced along or progressing from front to rear, and each pair includes an upper roller 76u and a lower roller 76l. The rollers of the respective pairs effectively engage in a film plane 78 disposed horizontally and extending from front to rear, this film plane constituting the locus in which the film passes through the dryer. A film to be dryed is indicated at 80, and it will be seen that the forward or leading edge is fed to the nip or bight of the first pair of rollers, and thus disposed substantially in the film plane 78, while the trailing portion extends forwardly.

Each roller 76 includes a central shaft 82 and a sleeve or sheath 84 on the shaft secured thereto in any suitable and known manner. The sleeve or sheath is preferably of rubber or similar resilient and high friction material. The sleeve is made up of a plurality of axially aligned and butted sections 85, forming slits 86 for receiving breakaway clips 88, these clips to be referred to again hereinbelow.

The shafts 82 are fitted in bearings 90 of suitable kind incorporated in stations 91, 92 which include end plates 93, 94 respectively, which in turn are fitted in the grooves 50, 72 identified above, in substantially airtight fashion filling the corresponding notches for effective control of air through the dryer.

At the right hand end of the roller assembly (FIG. 3) additional plate elements or mounting elements 96 are provided for mounting the corresponding ends of the roller shafts 82 and to mount and confine the gears 98, these gears including (FIG. 5) one on each of the shafts and are in mesh with each other either directly or through an idler 99 and a drive gear 100, the latter mounted on the drive shaft 102 of a motor 104 in the motor assembly 18. This motor assembly includes a base 106 with a flange 108 and having elongated slots 110 through which bolt means 112 extend. Upon loosening the bolt means, the motor can be shifted to the right (FIGS. 3 and 6) to inactive position, and in such position the drive gear 100 is withdrawn from operative engagement with the other gears 98. Upon removal of the nut means on the bolt means the motor assembly can be bodily withdrawn from the chamber.

Referring particularly to FIG. 4, the rollers 82 increase in diameter successively through the dryer from front to rear, i.e., the rollers 76b are slightly larger than the rollers 76a and the rollers 76c larger than the rollers 76b. Each increase in size is on the order of 0.020 to 0.040 inch in diameter. The peripheral speed is increasingly greater corresponding to increase in size, and the rollers are all driven at the same angular speed. The increase in peripheral speed may instead be produced by having the rollers driven at a great angular speed but the present arrangement is preferred whereby the rollers in each the upper and lower position can be placed in a common axial plane.

Incorporated in the roller assembly 16 also are air tubes 116. A fragment of one such tube is shown in perspective in FIG. 9, having an open end 118 and a closed end 120, and a plurality of apertures 122 spaced longitudinally therealong. The tubes are mounted between each two successive rollers in each the upper and lower groups, and rearwardly beyond the last of those rollers. The tubes are fixedly mounted and supported in the plates 93, 94, with their open ends communiating with the chamber 60. The apertures are directed toward the film plane 78, i.e., in the upper series downwardly and in the lower series upwardly, for directly impinging the air onto the film. Preferably the total open area of the apertures in one tube is about 10% less than the cross sectional area of the tube itself, to provide the desired back pressure for producing substnatially uniform air pressures through the apertures.

The breakaway clips referred to above are best shown in FIG. 4. Each clip is generally flat, preferably a plastic molded piece, having a hook formed by fingers 124, 126 fitted over the roller shaft 82. The fingers form an arcuate recess of slightly more than 180.degree., and frictionally hold the clip on that shaft, but enable the clip to be snapped off. At the other end the clip has fingers 128, 130 surrounding the adjacent air tube 116, defining a recess 132 having an arcuate curvature of 180.degree., and extending parallel beyond that point to enable the clip to be applied to and removed from active position. Also in FIG. 4 is an indication of the clip in detached position, the end at the roller is pulled upwardly either by the operator's fingers or by a hook under it, and that end raised toward the angular position shown in dot-dash lines, and the other end then easily withdraws from the air tube. The clip is replaced into active position in a similar manner in reverse direction. The clips at their first ends are fitted in the slots 86. The sections of the roller normally abut each other and they yield axially to receive the clips, but beyond the area where the clip is positioned, the roller sections tend toward each other and again interengage, and this interengagement extends for example approximately two-thirds of the circumference (FIG. 4) and particularly the portion at the film plane that engages the counterpart roller of the pair. Thus the surface of the roller that engages the film in feeding the film through is effectively continuous axially. The slits although nearly non-existent, may leave a very fine line of water on the film, and for this reason the clips are staggered both in direction from front to rear (FIG. 3) and as between the upper and lower rollers (FIG. 6).

As the film passes through the dryer, most of the quantity of water on the film is removed by the first pair of rollers 76a, and to catch the water the drip pan 24 is utilized. This drip pan may be molded plastic and includes an internal transverse baffle or wall 134. The drip pan is removable as indicated above, and merely slid into and out of position, when the feed roller 25 is out of position. This feed roller preferably also includes a shaft 135 and a sheath 136 of resilient material. The feed roller is mounted in clips 138 (FIGS. 3 and 8) with fingers 140 defining an upwardly opening socket for receiving the shaft, the fingers extending slightly more than 180.degree. for normally frictionally retaining the shaft in the socket. When the feed roller is out of position, as stated, the drip pan is easily removable and re-inserted into place. The feed roller 25 removes a portion of the water on the film, the roller being above the pan for that purpose and it also holds the film upwardly from contact with the front edge of the drip pan.

The baffle or wall 134 in the drip pan is of substantial height, being spaced from the roller 76i a small distance as indicated at 142 for minimizing air escape at that position as referred to again hereinbelow. The baffle 134 does not extend the full width of the pan, leaving gaps 144 for enabling water inwardly of that baffle to flow outwardly to the front portion of the drip pan.

The cover 22 is preferably a piece of sheet metal and provided with clips 145 (FIG. 4) removably fitted over the rearmost air tube 116. These clips enable the cover to hinge and also to be removed by merely snapping them off of the air tube. The cover may have a surrounding down turned flange resting on the plates of stations 91, 92 supporting the cover in closed position. The flange includes a front element 146 (FIG. 4) which is closely adjacent the upper front roller 76u leaving a small space 148 also restricting flow of air therepast and directing it toward the rear.

Upon flow of air through the air tubes, the air passing out of the apertures 122 is directed onto the film, and this air is for the greatest part, in the area around the rollers, directed to the rear. The cover flange element 146 and the baffle 134 prevent the escape of great amounts of air to the front, and the air then flows rearwardly and most of it passes out the rear, through the spaces around the rearmost air tubes 116 and the large space 150 below the roller assembly.

The motor-blower assembly 22 includes preferably two units 152 each including a blower 154 and a motor 156 mounted together on a mounting plate 158, dividing the chamber 60 into two sub-chambers or spaces 160, 162. The plate 158 is removably fitted in grooves 163 formed by flanges 164 on the sides and bottom (FIGS. 3 and 7). The sub-chambers 160, 162 are substantially airtight-separated and the top closure plate is removably placed over the box to close the sub-chambers, and the closure plate is provided with a flange 168 which engages the upper edge of the plate 158 holding the mounting plate against the pressure developed in the sub-chamber 160, i.e., against movement to the left (FIGS. 3 and 6). The motors 156 are provided with annular spaces 170 between the rotor and the stator, and air is forced therethrough as indicated by the arrows 174, by the blowers, more effectively cooling the motors.

In the operation of the device the motor-blower units 152 operate to draw air from the exterior through the apertures 54 at the right end (FIGS. 3 and 6), over the gears and motor, cooling those components and picking up heat therefrom. The air is then drawn through the apertures 54 and the filter 55, into the conduit 56 to the opposite end, and then through the apertures 58 into the sub-chamber 162. The blowers then force the air into the sub-chamber 160, and pressure is built up therein. This pressure then tends to deflect the plate 158 as stated, but the plate is restrained by the flanges 164, 168. The air is then forced into the air tubes 116 and because of the relative constriction by the apertures in the tubes, the air is forced out of the apertures at a relatively high rate onto the film. It will be understood that the top closure plates 26, 27 fit the boxes 34, 36 in airtight engagement.

The air circulated through the dryer and picking up heat from the motors and gears becomes unusually effective in drying the film. The greater volume of spaces through which the air passes, including the chamber 38, 60 -- and the air transfer 56 produces an unusually effective insulation against noise, these spaces occupying a relatively great portion of the total dimensions of the dryer, such for example as at both sides (ends) and below. The air transfer 56 produces great noise insulation, and because of its great width it can be very shallow, this arrangement adding to the compactness and simplicity of the overall construction.

The construction of the dryer is unusually simple; the operating components can be easily removed from the whole dryer; upon removing the top closure plates 26, 27, the drive motor assembly 18 can be retracted (FIG. 6) and then the roller assembly 16 removed; this can be removed with the cover still applied thereto, or the cover itself can be removed from the assembly; the drive motor unit 18 can also be removed; the motor-blower assembly 20 can be removed as a unit; the drip pan 24 can be removed, after removal of the feed roller 26, and all that remains is the rigid unitary frame. Thus the dryer can be easily serviced, an advantage in addition to the simplicity and relative economy in manufacture.

Additionally the breakaway clips 88 can be individually removed from the roller assembly, without removing the rollers from the roller assembly and of course without in any way taking apart any of the rollers themselves.