US 3304909 A
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Feb. 21, 1967 w HART ET AL APPARATUS FOR COATING CYLINDERS WITH URETHANE 3 Sheets-Sheet l Filed May 13, 1963 Feb. 21, 1967 w. s. HART ET L APPARATUS FOR COATING CYLINDERS WITH URETHANE Filed May 13, 1963 3 Sheets$heet 2 Feb. 21, 1967 w, A ET AL 3,304,909
APPARATUS FOR COATING CYLINDERS WITH URETHANE Filed May 13, 1963 3 Sheets-Sheet 5 United States Patent 3,304,909 APPARATUS FOR COATING CYLINDERS WITH URETHANE Wilbert S. Hart and John A. Scudder, Chicago, 111., as-
signors, by direct and mesne assignments, to Chemechanical, Inc., South Holland, 11]., a corporation of Illinois Filed May 13, 1963, Ser. No. 279,831 8 Claims. (Cl. 118-103) This invention relates to apparatus for coating cylinders with urethane or like material.
Various urethane formulations are widely used in industry, and most commonly articles formed of the urethanes and polyurethanes are cast either at room temperature or at slightly elevated temperatures. Various types of urethanes are particularly useful in coating various types of rollers, drums, pulleys and the like; but casting urethanes onto cylindrical articles is extremely difficult because of the need to locate the cylinder axis, or spindle, precisely in the center of the mold. The only practical procedure heretofore avail-able was to cast onto a cylinder an external layer which was considerably thicker than the finished diameter of the cylinder, and then grind the newly cast surface until it was perfectly concentric with the cylinder axis. Obviously this is a relatively slow and expensive operation.
In accordance with the present invention, the apparatus has coaxial spindles on which a cylinder is mounted and rotated at a slow rate of speed, i.e., somewhere between about 10 and 25 rpm. A thin layer of urethane or like material is fed onto the rotating cylinder where. it is smoothed and spread by a doctor blade until a coating of the desired thickness is obtained. A pressure roller then is used to work the coating and squeeze out air or other gas bubbles; and heating means are provided to hasten the cure of the coating. Ordinarily the coating is subjected to pressure from the roller and to heat for a substantial period of time after the deposition of urethane is complete, so as to properly work and cure the coating material.
The apparatus of the present invention includes means for adjusting the distance between the spindles to accommodate the device tothe coating of cylinders ofdiiferent length, means affording controlled radial movement of the doctor blade, the pressure roller, and a hopper from which the material pours onto the cylinder, not only to accommodate cylinders of different diameters, but also to permit necessary movement of each of the three radially movable elements of the machine during a coating operation.
Accordingly, the principal object of the present invention is to provide a simple and dependable apparatus for coating cylinders with urethane and like materials which set at room temperature or slightly elevated temperatures.
Another object of the invention is to provide apparatus for applying a coating of any desired thickness to a cylinder.
Yet another object of the invention is to provide apparatus for coating cylinders of various lengths and diameters with urethane or other like materials.
Still another object of the invention is to provide apparatus which may be used to apply a coating of urethane or like material to a cylinder in any desired thickness.
The apparatus of the present invention is illustrated in a preferred embodiment in the accompanying drawings in which:
FIG. 1 is a fragmentary side elevational view of the present coating apparatus with a curing cabinet omitted for clarity of illustration;
FIG. 2 is a vertical sectional view taken substantially as indicated along the line 2-2 of FIG. 1, with the curing cabinet in place; and
3,304,909 Patented Feb. 21, 1967 "ice FIG. 3 is a horizontal sectional view taken substantially as indicated along the line 3-3 of FIG. 1 with the curing cabinet in place.
Referring tothe drawings in greater detail, the apparatus includes a base, indicated generally at 10, having corner posts 11 at the upper ends of which are parallel longitudinal support rails 12, with diagonal bracing members 13. A platform 14 between two of the corner posts 11 supports a reduction gear box 15 having an input shaft 16 with a pulley 17 that is driven by a belt 18 from a motor (not shown) which may conveniently be mounted on the floor between the adjacent corner posts 11. An output shaft 19 on the gear box carries a pulley 20 from which a belt 21 encircles a pulley 22 on an input shaft 23 of a live center 24 that is journalled at 25 in a support bracket 26.
Slidably mounted on the parallel support rails 12 is a carriage 27 having sliders 270 on the support rails and a central boss 27b that embraces a center guide rod 12a; and a set screw 27c locks the carriage in any desired position. A central pedestal 28 on carriage 27 supports a dead center 29, so that a cylinder C to be coated may be spindled between the live center 24 and the dead center 29 for rotation during the coating process. By adjustingthe position of carriage 27 along the rails 12 the apparatus may accommodate a cylinder C of any length up to the maximum length of the rails 12. Preferably the apparatus is capable for receiving a cylinder at least 10 feet long, and may .be adjusted to accommodate a cylinder only a few inches long.
As illustrated in the drawings the gear box 15 is a single speed unit; but it is obvious to those skilled in the art that a variable speed unit might be employed so as to afford a substantially constant surface speed with cylinders of different diameters, as taught by Smith Patent 2,055,318.
As best seen in FIG. 2, a pair of generally U-shaped central support arms 30a and 30b extend outwardly and upwardly from the parallel rails 12 on opposite sides of the base frame, and at the upper ends of said arms are vertically oriented hydraulic cylinder and piston units, indicated generally at 31, which have their cylinders 32 bolted to the upper ends of the brackets 30, while their pistons 33 carry brackets 34 that are secured intermediate the ends of a materialhopper 35. As best seen in FIG. 1, at the ends of the hopper are stabilizing brackets 37 and 3-8 having sleeves 37a and 38a, respectively, that are impaled by guide rods 39 which extend upwardly from the corner posts 11 of the base. Thus, it is apparent that retraction of the piston rods 33 of the cylinder and piston units 31 lowers the hopper 35 with respect to a cylinder C, while extension of the piston rods raises the hopper with respect to the cylinder.
The material hopper 35 is seen in FIG. 1 to extend a distance equal to the maximum length of cylinder C which may be coated in the apparatus, and has a continuous longitudinal feed opening 40 in its lower end beneath which there is a slideway 41 for a slidable control gate 42 by means of which the length of the opening 40 through which material may be discharged from the hopper onto a cylinder C is controlled in accordance with the length of the cylinder being coated. As seen in FIG. 1, a guide member 420 extends between two of the guide rods 39 to support the outer end of control gate 42. A material guide plate 43 closes one side of the entire opening 40 and is slightly inclined as seen in FIG. 2 so as to direct material from the hopper onto the cylinder surface along a line which is just forward of the vertical median plane of the cylinder, forward and rearward here being used with reference to the clockwise direction of rotation of the cylinder C as viewed in FIG. 2.
Between the corner posts 11 at opposite ends of the apparatus are upright brackets 44 and 45 which provide supports for a doctor blade assembly, indicated generally at 46, and a pressure roll assembly, indicated generally at 47.
The doctor blade assembly includes a pair of opposed mounting plates 48 and 49 on the end brackets 44 and 45, with parallel arms 50 and 51 pivoted on the plates 48, arms 52 and 53 pivoted on the plate 49, a longitudinal tie rod 54 joining the arms 50 and 52, supporting flanges 55 and 56 which surmount the arms 5051 and 52-53, respectively, and a doctor blade 57 which has its ends secured to the flanges 55 and 56. Controlled, generally radial movement of the doctor blade 57 with respect to the cylinder C is afforded by a cylinder and piston unit, indicated generally at 58, there being a cylinder 59 pivotally mounted in a yoke 60 on the U-shaped arm 30a, and a piston rod 61 the outer end of which has a connector 62 embracing the tie rod 54. Thus, as the piston rod 61 is retracted it withdraws the doctor blade 57 generally radially with respect to the cylinder C, while extension of the piston rod 61 moves the doctor blade generally radially inwardly to accommodate the apparatus to a cylinder of smaller diameter than the cylinder C.
Also mounted upon the brackets 44 and 45 are bosses 63 and 64 which pivotally support arms 65 and 66, respectively; a tie bar 67 connects the arms 65 and 66; and a pressure roller 68 is journalled between the arms substantially directly opposite the doctor blade 57. Also carried upon arms 65 and 66 are brackets 69 and 70 which extend outwardly around the pressure roller 68 and then inwardly to support a trough 71 above the roller. A slot in the bottom of the trough is blocked by a wick 72, so that oil in the trough may be absorbed by the wick to maintain a thin film of oil constantly upon the entire surface of the pressure roller 68 so as to keep it from adhering to the outer surface of a layer L of coating material on the cylinder C.
Controlled radial movement of the pressure roller 68 is produced by a cylinder and piston unit, indicated generally at 73, said unit having a cylinder 74 pivoted in a yoke 75 on the U-shaped arm 30b, and a piston rod 76 having an eye 77 which embraces the tie bar 67 of the pressure roller assembly so that retraction or extension of the piston rod 76 moves the pressure roller 68 generally radially outwardly or inwardly with respect to the pivot axis of the cylinder C.
Proper operation of the apparatus requires that the coating material applied to a cylinder C be confined so that it does not run off the ends of the cylinder, and for this purpose a fixed doctor blade 78 is secured to the end of the hopper 35 adjacent the live center 24, while a movable doctor blade 79 is fixedly connected to the slidable closure 42 for the hopper 35 in such a location as to bear upon the adjacent end of a cylinder C in any adjusted position of the closure 42.
To accelerate curing of coating material in the layer L as material is applied to the cylinder C, the entire apparatus is enclosed within a curing cabinet, indicated generally at 80, which has a large hinged door 81 along one side affording access to the interior of the cabinet for changing cylinder C and making any needed adjustments to the apparatus. Any suitable heating means (not shown) may be provided to heat the interior of the curing cabinet 80. This may take the form of electrical or gas heating elements inside the cabinet, a system of pipes for circulating steam or hot water within the cabinet, or a hot air manifold and blower system for circulating heated air through the cabinet. In order that an operator may observe the progress of a coating operation, the ends of the curing cabinet 80 are provided with windows 80a, and the door 81 is provided with a window 81a.
Control of the hydraulic cylinder and piston units 31, 58, and 73 is afforded by a control box 82 having a control panel 82a on the outside of curing cabinet 80 alongside the door 81, and in the control panel 82a are three electrical control switches 31a, 58a and 73a of the three position toggle type which control, respectively, the operation of the hydraulic cylinder and piston units 31, 58 and 73. As will be obvious to one skilled in the art, the hydraulic cylinder and piston units are all connected by suitable conduits to solenoid valves in the control box 82, and the solenoid valves control admission of hydraulic fluid under pressure to the various cylinders 32, 59, and 74 in response to actuation of the toggle switches 31a, 58a and 73a which control energization of the solenoids which operate the valves.
By way of example, opposite ends of both cylinders 32 are provided with corresponding hydraulic lines 3117 and 31c with both lines 3112 connected to a line 31d and both lines 31c connected to a line 31c. Admission of hydraulic fluid through the lines 31d-31b extends both piston rods 33 simultaneously and at the same rate, while admission of hydraulic fluid through the lines 31c-31c retracts both piston rods 33 simultaneously. Toggle switch 31a has a mid-position in which the solenoid valves for both lines 31d and 312 are closed, a first active position which energizes the solenoid to open the valve in the line 31d-31b, and a second active position to energize the solenoid for the valve in the line 31c-31c. Similarly, hydraulic fluid lines 58b and 58c connect the cylinder 59 directly to valves in the control box 82 which are controlled by the toggle switch 58a while hydraulic fluid lines 73b and 73c connect the cylinder 74 to solenoid valves in the control box 82 which are controlled by the toggle switch 73a. Such simple electro-hydraulic control equipment is so commonly used in a wide variety of apparatus that no further detailed description or electrical or hydraulic circuit diagrams are necessary to a full understanding of the apparatus on the part of any person skilled in the art.
The electro-hydraulic controls permit an operator to effect controlled withdrawal of the hopper and the doctor blade as the layer L of coating material builds up on the cylinder; and to move the pressure roller as needed to properly work the material. Alternatively, of course, a suitable control may be provided to move the hopper and doctor blade automatically at a controlled rate in response to increasing thickness of the layer L. Movement of the pressure roller must be very delicate, in accordance with progress in the smoothing and compacting of the layer of polyurethane; so hand control of the pressure roller at the will of the operator is preferred.
While the apparatus of the present invention is illustrated herein as an entirely self-contained machine, it is quite apparent that the entire mechanism for supporting and operating the material hopper 35, the doctor blade assembly 46 and the pressure roller assembly 47 could be in the form of attachments for a pre-existing lathe, so that the cylinder C could be spindled between the centers of the lathe.
The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations are to be understood therefrom, as some modifications will be obvious to those skilled in the art.
1. Apparatus for coating a cylinder with urethane or like material, comprising, a frame, a pair of cylinder supporting spindles on the frame on a generally horizontal axis, means for driving one of said spindles at a relatively slow rate to rotate a cylinder supported thereon; one of said spindles being axially adjustable to accommodate cylinders of different lengths; hopper means for continuously applying coating material at a controlled rate to substantially the entire length of the cylinder; said hopper being radially movable with respect to said cylinder to thereby accommodate cylinders of different diameters; the hopper outlet being juxtaposed to and above the cylinder and comprising a material feed slot which is substantially as long as the longest cylinder which can be coated in the apparatus; means for selectively restraining the length of the slot to coincide with the length of the cylinder; a coating material guide attached to and coextensive with the side of said slot towards which the cylinder to be coated first approaches, said guide extending to the cylinder surface and extending in the direction of cylinder rotation; a doctor blade on the frame for continuously smoothing the coating material along the entire length of the cylinder as it is applied; a pressure roller on the frame for continuously compressing the smoothed coat of material on the rotating cylinder; said blade and roller being each mounted for movement which is generally radial with respect to the cylinder; and means to effect coordinated and simultaneous radial movements of the blade and roller.
2. Apparatus for coating a cylinder with urethane or like material comprising, a frame, a pair of cylinder supporting spindles on the frame on a generally horizontal axis; means for driving one of said spindles at a relatively slow rate to rotate a cylinder supported thereon; one of said spindles being axially adjustable to accommodate cylinders of different lengths; hopper means for continuously aplying coating material at a controlled arte to substantially the entire length of the cylinder; said hopper being radially movable with respect to said cylinder to thereby accommodate cylinders of different diameters; the hopper outlet being juxtaposed to and above the cylinder and comprising a material feed slot to which is substantially as long as the longest cylinder which can be coated in the apparatus; means for selectively restraining the length of the slot to coincide with the length of the cylinder; a coating material guide coextensive with the side of said slot towards which the cylinder to be coated first approaches; said guide extending to the cylinder surface and extending in the direction of cylinder rotation; a doctor blade on the frame for continuously smoothing the coating material along the entire length of the cylinder as it is applied; a pressure roller on the frame for continuously compressing the smoothed coat of material on the rotating cylinder; said blade and roller being each mounted for movement which is generally radial with respect to the cylinder; and means to effect radial movements of the blade and roller.
3. The apparatus recited in claim 2, in which the doctor blade is located at a point of cylinder rotation about from the hopper outlet and the pressure roller is located at a point of cylinder rotation about from the doctor blade.
4, The apparatus recited in claim 2, in which means is provided for applying a thin liquid film to the pressure roller to prevent the roller from sticking to the material on the cylinder.
5. The apparatus recited in claim 4, in which the liquid applying means comprises a liquid reservoir having an outlet disposed toward the pressure roller.
6. The apparatus recited in claim 4, in which a wick is arranged in the outlet, said wick contacting the roller.
7. The apparatus recited in claim 2, in which first hydraulic means is provided for effecting radial movement of the hopper means, second hydraulic means is provided for effecting radial movement of the doctor 'blade and third hydraulic means is provided for effecting radial movement of the pressure roller.
8. The apparatus recited in claim 2, in which means is provided to prevent coating material from running over the ends of the cylinder. 1
References Cited by the Examiner UNITED STATES PATENTS 373,670 11/1887 Lingle et a1 118-104 X 454,158 6/ 1891 Swanfeld-t 222-414 689,690 12/ 1901 Purves 118-107 915,672 3/ 1909 Harrington. 1,347,182 7/1920 Sleeper et a1. 118-415 2,133,516 10/1938 Huebner 118-320 2,321,732 6/ 1943 Brandt. 2,760,550 8/1956 Kimes 118-107 2,838,778 6/1958 Von Arx 118-107 X 2,933,061 4/1960 Ga'ler 118-241 X 3,042,968 7/1962; Kraszeski 18-155 MORRIS KAPLAN, Primary Examiner.