US 3537187 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Nov. 3, 1970 D. s. CVACHO EI' 3,537,137
. APPARATUS FOR AND METHOD OF, RAPIDLY DRYING COATING MEANS ON A WORKPIECE Filed Jan. 13, 1969 13 Sheets-Sheet 1 INVENTORS DANIEL s. CVACHO FIELD l. ROBERTSON,JR.
THEIR ATTORNEYS D. S. CVACHO ETAL A 3,537,187 APIDLY DRYING KPIECE Nov. 3, 1970 APPARATUS FOR AND METHOD 0 COATING MEANS ON A Filed Jan. 15, 1969 15 SheetS- Sheet 2 wa y W. mi E THEIR ATTORNEYS Nov. 3, 1970 I o. s. CVACHO ET 3,537,137
APPARATUS FOR AND METHOD OF, RAPIDLY DRYING Filed Jan 15, 1959 COATING MEANS ON A WORKPIECE 1.3 Sheets-Sheet 4 .ROBERTSON, JR Q INVENTORS l .S.CVACHO gawk, W. W
40 44 FIG.3 2 L g THEIR ATTORNEYS Nov. 3, 1970 D. s. CVACHO. ETAL 3,537,187
APPARATUS FOR AND METHOD OF RAPIDLY DRYING COATING MEANS ON A WORKPIECE l5 Sheets-Sheet 5 Filed Jan. 13, 1969 TIME IN SECONDSO I 2 3 4 5 6 7 OPERATING COND. RECEIVE8I DRYING BAKING ZONE 8 COOLING ZONE 0 EJECT CAN CLAMP cAN ZONE 0 I CAM POSITION EIUE ENTER ON LIvE CENTER OFF STEAM COOL AIR INSIDE 4 VACUUM L 250F 475F COOL AIR OUTSIDE CAN 4 T v T I73 I I I80 42 I83 a I8I I82 l II I 2I5 I I I I I I I 1 I I 0 .I 52 Q I 52 O 6 a I 0 INVENTORS 223 e 6 DANIEL S.CVACHO 0 o o FIELD I.ROBERTSON,JR.
H THEIR ATTORNEYS Nov. 3, 1970 s, CVACHQ ETAL 3,537,187
APPARATUS FOR AND METHOD OF RAPIDLY DRYING COATING MEANS ON A WORKPIECE Filed Jan. 13, 1969 13 Sheets-Sheet 6 INVENTORS Y DANIEL $.CVACHQ FIELD LROBERTSON, JR. %&n/ru am-vv vm BY v Ww \9/m am/ THEIR ATTORNEYS Nov. 3, 1910 D. s. CVACHO ETAL 3,537,187
APPARATUS FOR AND METHOD OF RAPIDLY DRYING COATING MEANS ON A WORKPIECE Filed Jan. 13, 1969 13 Sheets-Sheet 7 69 5O 40 Z 3 46 J 44 F|G.8 INVENTORS DANIEL S CVACHO FIELD l. ROBERTSON,JR.
THEIR AT TORN EYS Nov. 3, 1-970 s. CVACHQ ETAL 3,537,187
APPARATUS FOR AND METHOD OF RAPIDLY DRYING COATING MEANS ON A WORKPIECE. Filed Jan. 13, 1969 13 Sheets-Sheet 8 FIG.9
INVENTORS DANIEL S. CVACHO FIELD I. ROBERTSON, JR.
[MW/I v BY THEIR ATTORNEYS Nov. 3, 1-970 0. s. CVACHO ETAL 3,537,187
APPARATUS FOR AND METHOD OF RAPIDLY DRYING COATING MEANS ON A WORKPIECE Filed Jan. 13, 1969 l3 Sheets-Sheet 10 m s 0E N Y mmw M E mmm m WF T mm m m M N E w Mmv T DF 0/ Y %m on I mm D. S. CVACHO ET AL FOR ETHOD COATIN NS ON 3,537,187 OF RAPIDLY DRYING A WORKPIECE AND M G MEA Nov. 3, 1-970 APPARATUS l3 Sheets-Sheet 11 Filed Jan. 15. 1969 FIG. l3
INVENTORS DANIEL S. CVACHO FIELD l. ROBERTSON, JR. @flA,
THEIR ATTORNEYS 1970 D. s. CVACHO ETAL 3,537,187
APPARATUS FOR AND METHOD OF RAPIDLY DRYING COATING MEANS ON A WQRKPIECE' Filed Jan. 13, 1969 1.3 Sheets-Sheet 12 INVENTORS DANIEL S. CVACHO FIELD l. ROBERTSON,JR.
THEIR ATTORNEYS Nov. 3, 1970 Filed Jan. 13, 1969 D. S. CVACHO UAL APPARATUS FOR AND METHOD OF RAPIDLY DRYING COATING MEANS ON A WORKPIECE 1.3 Sheets-Sheet 1 3 INVENTORS DANIEL S. CVACHO FIELD I.ROBERTSON,JH
THEIR ATTORNEYS "United States Patent 3,537,187 APPARATUS FOR AND METHOD OF RAPIDLY DRYIYG COATING MEANS ON A WORK- PIECE Daniel S. Cvacho and Field I. Robertson, J12, Chesterfield County, Va., assignors to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Filed Jan. 13, 1969, Ser. No. 790,689 Int. Cl. F26b 7/00 US. Cl. 34-21 40 Claims ABSTRACT OF THE DISCLOSURE An apparatus for and method of rapidly drying coating means, such as printing ink, on the exposed surface of a workpiece, such as the side wall of a metal can, utilizing a heat source within the can to provide flash heating of the can body and cause the coating means to be dried from its inner surface outwardly to its outer surface and thereby provide high speed drying and a dried coating means of improved quality.
BACKGROUND OF THE INVENTION In order to dry coating means such as printing inks applied against exposed surfaces of a metal workpiece, such as a metal can, for example, considerable time is normally required during the ink drying process to increase the temperature of the metal can to enable the ink to dry. In general, previously proposed can drying apparatus and methods expose the exterior surface of the metal can to a high temperature which results in the form ing of a tough external skin on the printing ink which traps solvents contained in the printing ink intermediate the can body and the external skin and effectively prevents complete drying of the ink. In addition, present apparatus and methods require that each printed metal can be exposed to a high temperature for a comparatively long time interval ranging between six and eight minutes in order to provide acceptable drying of the printing ink whereby expensive and time consuming operations are required using present means to dry cans in mass production quantities.
SUMMARY This invention provides an improved apparatus for and method of drying workpieces such as cans made of heat conductive materials wherein each can is heated by exposing the inside surface thereof to a high temperature heat source to thereby heat the can and cause heat to be conducted therethrough toward the exposed surface of the can to dry coating means applied thereagainst from the inner surface of the coating means outwardly to the outer surface of such coating means and thereby provide high speed drying of the coating means and provide a dried coating means of improved quality.
Other details, uses, and advantages of this invention will become apparent as the following description of the exemplary embodiment thereof presented in the accompanying drawings proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show a present exemplary embodiment of this invention, in which FIG. 1 is a view in elevation with parts broken away illustrating an exemplary apparatus and method of this invention utilized to provide high speed drying of coating means applied on workpieces such as metal cans and also schematically illustrating a can transfer apparatus transferring freshly printed cans from a can printing machine onto the drying apparatus of this invention;
3,537,187 Patented Nov. 3, 1970 FIGS. 2A and 2B illustrate an enlarged view in elevation of the drying apparatus of FIG. 1 upon aligning FIGS. 2A and 2B along their respective break lines 2A2A and 2 B2B;
FIG. 3 is a view with parts in cross section and parts in elevation taken essentially on the line 33 of FIGS. 2A and 2B upon aligning such figures together along their respective break lines 2A2A and 2B-2B;
FIG. 4 is a view taken on the line 44 of FIG. 3;
FIG. 5 is a chart illustrating the time sequence used by the apparatus and method of FIG. 1 in first drying the coating means against each can, then baking the coating means, and finally cooling each can and its coating means;
FIG. 6 is a greatly enlarged view with parts in cross section and parts broken away of the lower end portion of the illustration of FIG. 3;
FIG. 7 is a view with parts in cross section and parts broken away illustrating a typical rotatable support provided on the apparatus of FIG. 1 and utilized to support the open end of a can to be dried;
FIG. 8 is a view looking essentially from left to right in FIG. 6 and illustrating a plurality of four rotatable supports and also illustrating a steam supply conduit in flow communication with a steam spray nozzle associated with each support;
FIG. 9 is an enlarged fragmentary view with parts in cross section and parts broken away particularly illustrating the manner in which open ended cans are transferred from a transfer apparatus to the drying apparatus of this invention while keeping undried coating means applied against the outer surface of the side wall of each can substantially intact;
FIG. 10 is an enlarged view with parts in cross section and parts broken away particularly illustrating a metal can held in position by an associated supporting device during the heating thereof to provide rapid drying of coating means applied against the exterior surface of such can and particularly illustrating the arrangement of a live center mechanism utilized to hold the can in position during the drying thereof while steam is injected into the can to provide flash heating of the can and hence rapid drying of the coating means applied against its side wall;
FIG. 11 is a greatly enlarged view with parts in cross section and parts broken away particularly illustrating an open ended can held in position by an associated supporting device during the steam heating thereof;
FIG. 12 is a fragmentary view similar to the lower portion of FIG. 10 and particularly illustrating the manner in which a linkage assembly comprising a supporting device for a pair of cans is effective in holding associated holding members tightly against the bottom wall of associated cans after the rear portion of the linkage assembly has been partially retracted by the engagement of its cam roller against a reduced height portion of its associated annular cam track;
FIG. 13 is a view taken essentially on the line 1313 of FIG. 10;
FIG. 14 is a view taken essentially on the line 14- 14 of FIG. 10; and
FIG. 15 is a greatly enlarged fragmentary View of the lower portion of the apparatus of FIG. I particularly illustrating the manner in which air is utilized to eject completely dried cans into an associated discharge chute.
DESCRIPTION OF ILLUSTRATED EMBODIMENT Reference is now made to FIG. 1 of the drawingsconductive material and in this example of the invention the apparatus is particularly adapted for providing continuous high speed drying of coating means applied against the exposed surfaces of tubular side walls of a plurality. of metal cans such as single piece cans made of metal containing aluminum and each having an outward- 1y concave bottom wall 22 adjoined by an integral tubular side wall 23 terminating in a slightly outwardly flared end edge 24 which defines an open end for the associated can 21, see FIG. 11. The apparatus 20 provides continuous, i.e. nonindexing, drying of coating means applied against the exposed outer surfaces of the metal cans and processes in excess of 600 cans per minute and with each can being processed in a total time of approximately six to seven seconds.
The term coating means as used in this specification includes within its scope the application of any suitable material on the exposed surface of a workpiece, such as a metal can, for example, any suitable ink, marking material, paint, protective varnish, adhesive means used to attach a separate label to a workpiece, etc. For ease of presentation the terms coating means, printing ink, and ink may be utilized interchangeably in this disclosure.
The cans 21 which are to be dried may be supplied in a continuous nonindexing manner to the apparatus 20 in any suitable manner. However, in this example of the invention the printed cans 21 are supplied from a can printing machine designated generally by the reference numeral 25 which prints the side walls 23 of single piece metal cans with printing ink in a continuous nonindexing manner and a typical can printing machine which may be utilized in association with the apparatus 20 is presented in patent application, Ser. No. 721,787, filed Apr. 16, 196 8. The exemplary apparatus 20 utilizes a transfer apparatus 26 for transferring wet or undried printed cans from the printing machine 25 to the drying apparatus 20 at high speeds and the transfer apparatus 26 operates in a known manner, which will be described later in this specification, to grasp each can 21 and transfer each can from the printing machine 25 to the drying apparatus 20 while maintaining the coating means or ink applied against its side wall 23 substantially intact.
The apparatus 20 has a supporting frame 31 which rotatably supports a wheel assembly 32 for rotation and in this example of the invention the wheel assembly or wheel 32 rotates in a substantially vertical plane, see FIG. 3. The wheel 32. has a central hub portion 33 provided as an integral part thereof and a supporting shaft 34 is fixed to the hub portion 33 and is rotatably carried by a pair of spaced antifriction bearings 35 with each bearing 35 being carried by a yoke-like support 36 which is fixed to the supporting frame 31.
The wheel 32 has a plurality of spaced can supporting devices 40 carried thereby adjacent its outer periphery for orbiting movement therewith. Each supporting device supports an associated can 21 while maintaining the undried coating means or in k applied against the exposed surface of its tubular side wall substantially intact.
The apparatus 20 is provided With means for heating the inside surface of the side wall of each can during orbiting movement thereof by the wheel 32' and, in this example of the invention a plurality of steam spray heads 44, each operatively connected to an associated steam supply conduit 45, is provided with each spray head being adapted to inject steam against the inside surface of the side wall 23 of an associated can. Steam is supplied to each stem spray head 44 in a manner as will be described in detail subsequently in this specification and upon ejecting steam against the inside surface of each can 21 the entire thickness of the side wall 23 is heated substantially instantaneously and such substantially instantaneous heating by steam may be referred to throughout this specification as flash heating. As each can body is rapidly heated, heat is conducted through the side wall to dry the coating means from its inner surface outwardly to its outer surface to thereby provide a dried coating means of high quality which is thoroughly and uniformly dry throughout its entire thickness.
The rotatable wheel 32 is comprised of a plurality of radially extending structural members 41 each suitably fixed to the central hub portion 33 and a substantially U-shaped member or channel 42 is fixed to the outer end of each radial member 41 so as to extend in a circular path and with the outwardly extending legs of the U- shaped member 42, as viewed in cross-section, extending inwardly toward the center of the Wheel 32. The previously mentioned can supporting devices 40 are fastened to the peripheral structural member 42 at equally spaced apart locations.
As seen particularly in FIGS. 6 and 7 of the drawings each supporting device 40 comprises a rotatable support 46 having an outwardly facing supporting surface 50 which is adapted to receive the end edge 24 of the side wall 23 of an associated can 21 thereagainst and a holding member 51 which is adapted to engage the bottom wall 22 of each can and hold the open end of its associated can in tightly sealed relation against the outwardly facing supporting surface 50. Each support 46 is fixed to a tubular extension 49 provided on a pulley 52 which is clamped against a. nut shaped portion of extension 54 by a threaded member 53 which is threaded on the freely rotatable threaded extension 54 comprising a part of a fluid connector assembly 55 whereby the threaded extension 54, pulley 52, and support 46 are all freely rotatable yet the connector assembly 55 has its outer housing 56 fixed in position with a fluid-tight seal being provided between the housing 56 and the extension 54.
The supporting housing 56 of connector 55 is suitably fixed to a support 60, see FIGS. 6, 7 and 14, which is in turn fixed to the peripheral channel 42 by a bracket 61 and a pair of bolt and nut assemblies 62. An antifriction bearing 63 is provided between the housing portion 56 of the assembly 55 and a fluid-tight seal 64 is also provided between the rotatable extension or member 54 and the housing 56. Thus, it is seen that the support 46 is rotatable and may 'be easily rotated by rotating the pulley 52 to thereby provide more efiicient drying, baking, and cooling of coating means applied against the side wall 23 of an'associated can 21 and as will be described in detail subsequently in this specification.
The steam spray head 44 comprising each supporting device 40 is carried at a fixed position relative to the rotatable wheel 32 and steam is conveyed through an associated steam supply conduit 45, through an associated assembly 55, and through a spray head 44 so that it impinges against the inside surface of an associated metal can 21, see FIGS. 10 and 11. Each assembly 55 also has passage means 69 extending from the exterior surface of member 54 through the assembly 55 and in flow communication with one end of a conduit 65. The opposite end of the conduit 65 is in flow communication with a chamber 6 6 which may be selectively connected either to an exhaust means such as a vacuum pump or a source of air under pressure and in a manner to be described in more detail subsequently.
As seen particularly in FIG. 11 of the drawings, each holding member 51 of each supporting device 40 is carried by an externally threaded tubular housing 70 which has a substantially smooth bore 71 extending therethrough. The member 51 is fixed to a central shaft-like member 72 which is supported for axial sliding movement and for rotating movement by a cylindrical sleeve bearing 73 carried within the housing 70. The member 72 has a right circular cylindrical extension rod 74 fixed thereto which extends outwardly beyond the opposite end of the housing 70 and the rod 74 is supported adjacent such opposite end of the housing 70 for both axial sliding movement and rotating movement by a bearing 75.
The member 51 may be fixed to the member 72 by a set screw 80 and a compression spring 81 is provided acting between the bearing 75 and a thrust ball bearing 82 to normally yieldingly urge the holding member 51 outwardly toward the bottom wall 22 of an associated metal can 21. A stop collar 83 is fixed to the .outer end of the rod 74 and limits the amount that the spring 81 can push the holding member 51 outwardly. The spring 81 compensates for cans 21 having different heights, Within predetermined tolerance limits, to assure that each can is held tightly against the outwardly facing supporting surface 50 of its rotatable support 46. Thus, it is seen that each holding member 51 has antifriction bearings 73, 75 and 82 which enable it and each can 21 against which such member is urged to be rotated in a substantially friction-free manner.
As previously mentioned each can 21 in this example of the invention is transferred to the drying apparatus utilizing the transfer apparatus 26 and initially each can 21 is telescoped with its open end around the rodlike spray head 44 and in some applications of this invention the spray head 44 may be effectively utilized as a supporting pin for an associated can. Immediately following transfer of a particular can in telescoped relation over an associated spray head 44 the holding member 51 is actuated by a mechanical linkage assembly, which will be designated generally by the reference numeral 90, see FIGS. 6 and 10, so that the member 51 engages the outwardly concave bottom wall 22 of a particular can 21.
The outwardly facing supporting surface of each rotatable support 46 comprises a substantially frictionless frustoconical cam surface which allows the edge 24 of an associated can 21 to be readily slid thereacross in a nonsticking and substantially frictionless manner. The holding member 51 may also be provided with a convex surface 91 which may correspond to the configuration of the outwardly concave bottom wall 22. Once the holding member 51 engages the bottom wall 22 the net effect is to cam the end edge 24 along surface 50 to precisely position the can 21 in spaced relation from and substantially concentrically around its associated spray head 44 while simultaneously clamping the end edge 24 and hence the open end of the can 21 against the frustoconical supporting surface 50 in a substantially fluid-tight manner.
The apparatus 20 has a plurality of the previously mentioned linkage assemblies 90 carried by the rotatable wheel 32 adjacent its outer periphery. Although each can holding member 51 may be provided with an individual linkage assembly 90, in this example of the invention each linkage assembly 90 is operatively connected to simultaneously actuate a plurality of two holding members 51 against a pair of associated cans 21, see FIGS. 8 and 13.
As previously indicated each holding member 51 is carried by an externally threaded housing and a pair of housings 70 are each fixed in spaced relation on a support plate 92 by a pair of cooperating threaded nuts 93. A roughly S-shaped arm 95 is fixed to each plate 92, see FIGS. 6 and 10, and the arm 95 is pivotally supported by a lug 96 which is fixed to a support member 97 and member 97 is fastened to the U-shaped channel 42. The arm 95 is supported for free pivoting movement by a pivot pin 100.
The linkage assembly also comprises a telescoping tubular member 102 which is connected to the arm by a short link 103 and a pair of pivot pins 104 and 105. The support member 97 has a flange 106 fixed thereto which supports a cylindrical sleeve bearing 110 and the telescoping member 102 is supported for axial sliding movement through the sleeve bearing 110 in a substantially frictionless manner.
The tubular member 102 has a telescoping rod 111 slidably supported therein and the member has an elongated slot 112 which is adapted to receive a pin 113 fixed to one end of the rod 111. The pin 113 is adapted to engage side surfaces defining the sides of slot 112 to prevent the rod 111 from rotating during telescoping movement thereof and surface portions of the tubular member 102 defining opposite ends of the slot 112 are adapted to be engaged by the pin 113 to limit the axial movement of the telescoping rod 111. A compression spring 115 is provided and acts between a member fixed to one end of the tubular member 102 and the near end of the rod 111 to continuously yieldingly urge such rod outwardly.
The tubular member 102 has a sleeve bearing 116 suitably fixed thereto adjacent its rear end portion and the rod 111 is supported for axial sliding movement by the sleeve bearing 116. The member 102 also has a collar 120 fixed concentrically around its outer surface adjacent the rear portion thereof and a compression spring 121 is provided and acts between the forward support 106 and the collar 120 to normally yielding urge the member 102 and the telescoping rod 111 carried therein rearwardly so as to pivot the S-shaped arm 95 and hence holding member 51 to a. retracted position.
The rear portion of each linkage assembly 90 is supported by an associated tubular support 123 which is fixed to the plate 61. The tubular support 123 has a sleeve bearing 124 defining its inside surface and the rear end portion of the telescoping rod 111 extends substantially axially through member 123 and its integral bearing 124.
The rod 111 has a telescoping cylindrical member 125 fixed thereto and a bolt 126 is threaded into the member 125 and carries a freely rotatable cam roller 130 at its outer end. The tubular support 123 and sleeve bearing 124 have a pair of aligned longitudinal slots 131 and 132 respectively. With the member 125 fixed to the rod 111 and the bolt 126 extending transversely and outwardly from member 125 the aligned slots 131 and 132 are dimensioned to allow free axial movement of the bolt 126 and hence cam roller 130 as the rod 111 is moved axially along the sleeve bearing 124. Thus, it will be appreciated that the position of each holding member 51 is precisely determined by its associated linkage assembly 90 (two members 51 are simultaneously controlled by a single linkage assembly 90 in this example of the invention) and such linkage assembly is precisely and accurately controlled by its cam roller 130 as will now be described in detail.
As seen particularly in FIG. 3 of the drawings the apparatus 20 has an annular cam track 133 fixed to the stationary supporting frame 31 and the cam track 133 has a contoured cam surface which is engaged by the cam roller 130 of each mechanical linkage assembly 90. The operation of the linkage assembly 90 is such that after each can 21 is transferred by the transfer apparatus 26 onto the apparatus 20 and as a particular pair of cans 21 move toward the position designated by the reference numeral 134 in FIG. 1, the cam track 133 moves the cam roller 130 and hence the entire linkage assembly 90 so that its associated pair of holding members 51 engage the bottom walls 22 of its pair of associated cans 21 to urge and hold the edge 24 of each can 21 against its associated frustoconical supporting surface 50. At position 134 steam is started to be injected into each can 21 for a precise time interval as determined by the configuration of the cam track 133.
In this example of the invention steam is injected into the inside of each can for a time interval of one second. The apparatus for injecting steam into each can 21 with the can held tightly in position in a fluid-tight manner will be described in detail subsequently and such apparatus is also precisely operated by a portion of a selected linkage assembly 90 as controlled by an associated cam roller 130 engaging the cam track 133.
Each linkage assembly 90 operates so that its holding member 51 moves completely away from a rod-like steam spray head 44 and allows the can 21 to be telescoped in position thereon by the transfer apparatus 26. Once the cam track 133 actuates a linkage assembly 90 the linkage assembly moves to the position illustrated in FIG. 10 of the drawings and holds its associated pair of cans 21 in position in a fluid tight manner.
Each linkage assembly operates so that its members 51 may be held tightly against its associated cans 21 during a condition where the cam roller 130 and hence telescoping rod 111 are actuated a maximum amount by the cam roller 133 and essentially as illustrated in FIG. 10. In addition, the operation of the linkage 90 is also such that with the cam roller 130 moved rearwardly (by a section of the cam track 133 of reduced height) from its full forward position to the position illustrated in FIG. 12, the associated holding members 51 are still maintained in their full forward holding positions against a pair of associated cans 21. The condition wherein the cam track 133 holds a rotatable member 51 against a can 21 may be referred to in this specification and in FIG. of the drawings as a live center on condition. When each member 51 is retracted or moved away from its can 21 this may be referred to as a live center oif condition. Thus, with an associated cam roller moved from the position illustrated at 135 in FIG. to the position illustrated at 136 in FIG. 12 the live center is still on, i.e., each rotatable holding member 51 associated with a particular can 21 is still held urged against such can. Having described in detail the component parts of the linkage assembly 90, the description will now proceed with the description of the heating means in the form of a steam heating system utilized to provide flash heating of each can 21 and its coating means and for this description particular reference is made to FIGS. 2A, 2B and 3. The apparatus has a steam supply chamber 140 provided in the central portion of the rotatable wheel 32 and defined by a tubular housing 141 fixed in a sealed manner at its inner end against a plate 142 comprising the hub portion 33 and a plate 143 is fixed to the outer end of the housing 141 in a sealed manner.
Steam at a predetermined controlled temperature and pressure is supplied to the chamber 140 through a supply pipe 144 from a suitable steam source through a fluid coupling 145 which has a terminal end 146 which is threaded through the plate 143 in fluid flow communication with the chamber 140. The coupling 145 enables the supply pipe 144 to be maintained in a fixed position while allowing free rotation of the wheel 32 with steam being supplied to the chamber 140 in a fluid-tight manner. The steam heating system also has a plurality of comparatively short radially extending supply lines 150 threadedly fastened in position about the circumference of the tubular member 141 in angularly spaced relation and each line 150 is in fluid flow communication with the steam chamber 140.
The apparatus 20 also has a plurality of steam valves 152 and each steam valve has its inlet operatively connected to an associated steam source and its outlet operatively connected to its associated steam supply lines 45. Although each supply line 45 and steam head 44 may have its own steam valve or any desired number of steam heads may be supplied from a single steam valve, in this example of the invention each steam valve 152 supplies steam to four steam heads or nozzles 44 through associated lines 45 and as will be readily apparent at 154 in FIG. 2A and at 155 in FIG. 2B. Each steam supply line 45 is suitably interconnected to its associated steam valve 152 utilizing a standard T connector.
The steam heating system also has an intermediate steam conduit system for supplying steam from the radial lines 150 to each steam valve 152 and in the example of the invention a toroidal manifold 153 is suitably fastened to the radial supporting members 41. The manifold 153 is connected in fluid flow communication with the radial lines by a plurality of conduit assemblies 156 and each assembly may have a flexible central portion. The manifold 153 has a plurality of tubes 160 extending radially outwardly therefrom with each tube 160 being fastened in fluid communication'with an associated steam valve 152.
As previously mentioned, each steam valve 152 is actuated by an associated .linkage assembly 90 and in a manner now to be described and for this presentation reference is made to FIGS. 6, 10 and 12 of the drawings. In particular, each alternate bolt 126 has a member 162 suitably fixed thereto which carries an adjustable actuating member in the form of a threaded bolt 163 at the outer end thereof. The member 163 is adapted to engage a pivoted steam valve actuating arm 164 which is pivoted about a pivot pin 1'65 and operates to depress a plunger 166 and open the associated valve 152.
As the cam roller 130 moves around the cam track 133 and a set of four cans 21 to be dried reaches the position indicated at 134, FIG. 1, at the beginning of the drying zone which is designated by the reference letter D, the cam track 133 moves the associated cam roller 130 outwardly, causing the member 163 to actuate the lever 164 to provide steam flow through the steam valve 152 and to an associated set of four cans 21. The drying action in this example of the invention takes place during a one second time interval, see FIG. 5, and as the set of four cans is orbited past the drying zone D the con-figuration of the cam track 133 is such that the member 163 is retracted by the cam track to the position illustrated in FIG. 12. In this position, it will be seen that the actuating arm or lever 164 is released and steam to such set of cans 21 is instantaneously shut oif. As previously suggested, with each steam valve 152 supplying four steam heads 44 and with each mechanical assembly 90 actuating only two holding members every other assembly 90 is provided with an actuating member 163.
However, as previously explained, the operation of the associated linkage assembly 90 together with the configuration of the cam track 133 is such that each can 21 is still held tightly against its associated rotatable support 46. In particular, it will be seen from FIG. 10 that the configuration of the cam track 133 is such that the pin 113 is moved from the position illustrated at 170 in FIG. 10 to the position illustrated at 171 in FIG. 12 as the cam roller 130 and rod 111 follow the contour of the cam track 133; however, the tubular telescoping member 102 remains in the position of FIG. 10 whereby the associated holding members 51 are held in their actuated position for a time interval as determined by the configuration of the cam track 133.
During the steam drying of each set of four cans, the steam which is ejected into each can 21 is exhausted or evacuated through associated passage means 69, through an associated assembly 55, and then through an associated conduit 65 to the chamber 66.
The chamber 66 is defined by a pair of cooperating hat-shaped, as viewed in cross section, members 172 and 173, see FIGS. 3, 4 and 10. The hat-shaped member 172 is fixed to the rotatable wheel 32 and rotates therewith; however, the member 173 is a stationary member and is fixed to the supporting frame 31. The cooperating members 172 and 173 define the chamber 66 which extends completely around the apparatus 20 and is in the form of a toroidal chamber of rectangular crosssectional outline.
As seen in FIG. 4 of the drawings the member 173 has a baflie 174 fixed thereto at a position which is generally upstream of the transfer apparatus 26 and another bafiie 175 which is fixed thereto at a position which corresponds to the end of what will be referred to as the baking zone B (see FIG. 1) for the coating means and such baking zone will be described in detail subsequently. The bafiies 174 and 175 are in the form of flat plates each fixed to the member 173 and each baflle extends transversely across the chamber 66 to divide the chamber 66 into two sections 180 and 181. The section 181 is operatively connected by a pipe 182 to a vacuum system or pump and serves to evacuate steam injected into each can 21 to assure that the outer surface of each can is maintained in a dry condition. The section 180 is operatively connected to a duct 183 and is supplied with pressurized cooling air such as air at room temperature, for example, which is forced into the section 180 and then reversely through each conduit 65 and passage means 69 to cool the inside of each can. Further, the cool air supplied through duct 183 is also utilized to eject each can 21 from the apparatus 20 and in a manner as will be described in more detail subsequently.
The apparatus 20 is provided with an air deflector assembly 187, see FIGS. 3 and 10, which extends completely around the Wheel 32 and is carried thereby. The assembly is of U-shaped cross-sectional configuration and its outwardly extending legs 188 and 189 extend in an opposite direction from the legs of the channel member 42. The leg 188 of assembly 187 also serves as a stop for each plate 92 as it is actuated into holding position by an associated linkage assembly 90 and the leg 189 has an opening which receives an associated pulley extension 49 therethrough and allows free rotation of such extension and a rotatable support 46 fixed thereto. Each deflector assembly 187 cooperates with associated plates 92 to assure air is circulated around each can 21 during the drying, baking, and cooling of its coating means and as will be described in detail subsequently.
The apparatus 20 has an air supply system for floW- ing air under controlled conditions, such as temperatures, pressures, and velocities about the outer surfaces of the cans 21 and during orbiting movement of such cans by the rotatable wheel 32. The air is used to assure the provision of a dried coating means of optimum quality.
The air supply system comprises an inner air nozzle 185 of substantially inverted U-shaped configuration which is supplied with hot air at high velocity by a duct 186, see FIGS. 1, 2A, 2B, and 10. The nozzle 185 is supported within an outer substantially inverted U-shaped, as viewed in cross-section, duct 190 and the duct 190 serves as an exhaust duct for exhausting air which has been supplied to the cans 21 by the nozzle 185. The duct 190 has a pair of exhaust pipes 192 and 193 arranged in spaced relation and adapted to return heated air which has previously been flowed around the cans 21 away from the apparatus 20 to an associated hot air source.
The air supplied through duct 186 is supplied at a high velocity generally of the order of five thousand feet per minute and at temperatures ranging between 450 to 475 degrees Fahrenheit. Air is flowed around the outside surface of the cans 21 during the one second that steam is supplied to the inside of each can to provide flash heating thereof and drying of the coating means on each can 21. However, to assure that a tough dried skin is not created on the coating means or ink provided on each can due to the 450 to 475 degrees Fahrenheit air, the nozzle 185 is spaced from the outer periphery of the cans 21 a predetermined controlled distance as indicated at 195, see FIG. 1, whereby the effective temperature of the heated air impinging against each can 21 during the drying of the can in the drying zone D (by injecting steam into the inside of the can) is generally of the order of 250 degrees Fahrenheit. This 250 degree air blanketed around each can 21 is not sufficient to cause skinning or the forming of a hard crust on the outer surface of the ink provided in each can 21.
As will be apparent from the chart in FIG. 5 of the drawings during the flash heating by steam and drying of the coating means (drying range D) on each can for one second the outside of the can is blanketed with 250 degrees Fahrenheit air provided at velocities of 5,000 feet per minute and this air carries away gaseous impurities, vapors, and the like expelled by the coating means during drying. After the one second drying interval the hot air provided by the duct 186 is effective in baking the coating means on each can 21 and as will now be described.
As previously explained, the air provided by the duct 186 is provided at 450 to 475 degrees Fahrenheit. To utilize the maximum temperature of this air the configuration of the nozzle is such that it is arranged closely adjacent the outer periphery of the cans 21 from a location inllustrated at 200 in FIG. 1 and for the remainder of the nozzle 185 to a location indicated at 201 to define what will be referred to as a baking zone B for the coating means applied on each can 21. In the baking zone B the above described arrangement of the nozzle 185 assures that 450 to 475 degrees Fahrenheit air is flowed around each can which is eifective in baking and chemically converting the coating means on each can 21 to assure provision of a coating of optimum quality. As will be apparent from FIG. 5 of the drawings the baking of the coating means on each can 21 is achieved in a time interval of approximately two seconds and during this time the heated air is provided at 450 to 47.5 degrees Fahrenheit and at approximately 5,000 feet per minute.
At the completion of the baking of the coating means on each can 21 both the inside and outside of each can 21 is cooled to remove the plastic condition of the baked coating and prevent subsequent scufling of the coating during the handling of each can. The air supply system includes a cooling nozzle 202 which is similar in configuration and arrangement to the nozzle 185 and extends over a predetermined are around the outer periphery of the apparatus 20 to define a cooling zone which will be designated by the reference letter C. The cooling air may be essentially at room temperature or may be suitably cooled to a lower temperature, if desired.
Cool air for the outside of the cans 21 is provided to the nozzle 202 by a pipe 203 and the cool air flows around each can 21 during orbiting movement thereof by the apparatus 20 and is moved away from the cans 21 by a return duct 204 which is similar to the duct and surrounds the cooling nozzle 202. The duct 204 has an exhaust pipe 205 connected thereto and the pipe 205 may be connected to a suitable vacuum pump, exhaust fan, or the like. The cooling nozzle 202 provides cooling for each can 21 as it is moved into the cooling Zone C and the arcuate length of the nozzle 202 in this example of the invention is such that it provides cooling air around the outside surface of each can for a time interval of two seconds, see FIG. 5.
At the time that cooling air is introduced around the outside of each can, cooling air is also provided to the inside of each can. This cooling of the inside of each can 21 is also illustrated in FIG. 5 and the cooling air is provided through the section 181 of chamber 66 with the cooling air being provided through duct 183 as previously mentioned see FIG. 4. Cooling air is provided to the inside of each can for a time interval of three seconds in this example of the invention. This three second interval includes one second wherein air is only provided to the inside of the can and downstream of the cooling zone C.
As will be apparent from FIG. 5, each can 21 is held tightly against the rotatable support by its live. centerthroughout the drying, baking, and cooling zones. The live center is released after approximately six seconds that a can has been in the apparatus 20.
As each pair of cans 21 held by a linkage assembly moves out of the cooling zone C the live center is released and this release is controlled by the configuration of the cam track 133. Once the live center on each can 21 is released the holding member 51 for each can is moved completely away from the can and the air under 1 1 pressure supplied to the inside of each can 21 is eflective in propelling each can away from its support 46 into a discharge chute 210 and as illustrated in FIG. 15 of the drawings.
The discharge chute 210 has a contoured configuration and is inclined downwardly and away from the apparatus 20 so that each now completely dried and cooled can may be moved rapidly away from the apparatus 20 by the gravity chute 210. The configuration of the chute is also such that it assures that a bottom corner portion 211 of each can strikes the inside surface of the chute 210 to assure that the dried coating means on the side wall of each can 21 will not be damaged.
To assure more efficient drying, baking, and cooling of the coating means applied against each can 21, means is provided for rotating each rotatable support 46 and hence the associated can 21 during orbiting movement of each can by the rotatable wheel 32. The can rotating means will now be described in detail.
As previously explained, each support 46 is a rotatable support and is fixed to the extension 49 of an associated pulley 52 and each pulley has an annular groove 213 provided therein. The apparatus 20 also has a belt-like member 2'15 which extends about the outer periphery of the apparatus 20, see FIGS. 3 and 4, and has one end 216 fixed to a bracket 220 which is in turn fixed to the stationary housing member 173. The opposite end of the belt-like member 215 is fastened to yielding means in the form of a tension spring 223 which is fastened to another bracket 221 which is also fixed to the member 173. The spring 223 yielding holds the member 215 against the pulleys 52 around the outer periphery of the apparatus 20.
The member 215 has substantially trapezoidal crosssectional configuration and is made of an essentially nonstretchable material and the cross-sectional configuration of the member 215 is such that it is received within each groove 213 to engage each pulley 52 so that by rotating the wheel 32 to provide orbiting movement of each support 46 and can 21 carried thereby the engagement of an associated pulley 52 against the belt-like member 215 also causes rotation of each support 46 and hence each can 211 during its orbiting movement. Thus, it is seen that simultaneous orbiting movement and rotating movement of each can 21 during the drying, baking, and cooling periods assures maximum drying, baking, and cooling efficiency to enable complete processing of a can within a small time interval of roughly seven seconds which is substantially less than the six to eight minutes usually required merely to dry coating means applied against a can body using previously proposed devices and methods.
As seen particularly in FIG. 11 of the drawings each steam spray head 44 has a plurality of spaced orifices 230 provided therein and a greater number of such orifices are provided adjacent the terminal end 231 of each spray head 44 to provide instantaneous heating of the bottom wall 22 of each can 21 together with the instantaneous heating of the side wall 23. It will be appreciated that in many instances the bottom wall 22 of a particular can, such as a single piece can, may be thicker and hence require more heat, whereby the arrangement of the orifices takes care of this condition.
The steam spray head 44 of this example also has an offset as shown at 233, which assures that the steam orifices 230 are arranged more closely adjacent the outer periphery of the cylindrical side wall 23 and as indicated at 234 as each can 21 is rotated by its support 46 during its orbiting movement and during the drying portion of the cycle. However, it will be appreciated that this is a feature to provide more efficient steam heating and it may be preferred in many applications of this invention to provide a straight steam spray head 44 extending essentially centrally through each can 21 with each can held in posisteam to be utilized will be determined by the configuration and size of each can and the nature of the coating means to be dried. It will also be appreciated that the holding member 51 and the support member 46 are made of a heat resistant material such as a rubber-like material which is not likely to be deformed or damaged by heat with repeated use thereof.
The exemplary transfer apparatus 26 which is utilized to transfer cans 21 onto the apparatus 20 may be of any suitable construction and is preferably of the type that is capable of transferring cans onto the apparatus 20 in a continuous nonindexing manner. Except for its peripheral configuration the apparatus 26 has components which are similar in operation and construction to like components of a similar transfer apparatus presented in the abovementioned copending patent application, Ser. No. 721,787.
The apparatus 26 has a peripheral track 241 which carries and guides a chain conveyor 240 in a predetermined controlled path about the track 241, see FIGS. 1 and 9. The chain conveyor 240 is an endless conveyor and is moved by any suitable device about its track 141. The conveyor 240 has a plurality of vacuum devices 243 fixed thereto at predetermined spaced intervals and the track 2411 has an arcuate section 142, FIG. 1, which corresponds to a portion of a path traveled by spray heads 44 during orbiting movement thereof. The moving means for the conveyor 240 moves each device 243 and its can 21 at the same speed as an associated support 46 and the conveyor 24-0 is synchronized so that during movement thereof and rotation of the Wheel 32 each can 21 is aligned opposite a support 46 over practically the entire arcuate section 242.
Each can 21 is removed from the printing machine 25 and moved by an associated vacuum device 243- until it is positioned into the arcuate section 242. The configuration of the cam track 241 in addition to having arcuate portion 242 which corresponds to the arcuate path traveled by the steam heads 44 and supports 46 also has a cam section 245 which is effective in physically positioning each cam 21 in telescoped relation over an associated steam spray head 44 as illustrated in FIG. 9. Once each can is telescoped in position the vacuum nor mally applied on each vacuum device 243 is released and a spring 246 provided at the terminal end of each vacuum device 243 is effective in propelling each can over its steam spray head 44 and against frustoconical surface 50 of an associated rotatable support 46.
At this point in the operating cycle it will be appreciated that vacuum is being applied through the passage means -69 in each rotatable support 46 whereupon each can is held by vacuum tightly against its associated frustoconical surface 50. Thus, each can 21 is effectively transferred by the transfer apparatus 26 from the printing machine 25 to the drying apparatus 20 in a continuous nonindexing manner and while maintaining the coating means or ink on its side walls substantially intact.
Having described in detail the various members of the apparatus 20 a brief general description will now be made to highlight simplicity and rapidity with which cans 21 may be processed on the apparatus 20 within a total time interval generally of the order of seven seconds and for this general description particular reference is made to FIGS. 1, 3 and 5 of the drawings.
The cans 21 to be dried are transferred by the transfer apparatus 26 onto the wheel 32 of apparatus 20 and around the rod-like spray heads 44 in a continuous nonindexing manner. As the wheel 32 of apparatus 20 continues to rotate the cam track 133 moves each linkage assembly as it approaches the drying zone A so that after approximately one-half second of elapsed time from the time a particular can 21 is introduced onto the apparatus 20 a holding member 51 for the can is urged thereagainst to clamp the particular can against an associated rotatable support 46.
At approximately one second of elapsed time the configuration of the cam track 133 is such that the linkage assembly 90 operates to open an associated steam valve to simultaneously eject steam into a set of four cans. The Steam valve is held open and steam is injected into each can of the set of four for a period of one second. This is the drying portion of the cycle and takes place in the drying zone D.
During the one second of steam heating, air at approximately 250 degrees Fahrenheit and 5000 feet per minute is supplied around the outer surface of each can and serves to carry away gaseous impurities expelled during the steam drying of each can. The steam provides substantially instantaneous or flash heating of the entire metallic bottom Wall and side Wall of each can causing heat to be conducted outwardly so as to dry the coating means from its inner surface to its outer surface.
At the completion of the one second drying cycle the steam is shut off and hot air at 450 to 475 degrees Fahrenheit is flowed around the outside surface of each can for a time period of two seconds to bake the coating means on each can. The hot air is also provided at 5000 feet per minute and the baking takes place in the baking zone B.
During the drying and baking portion of the cycle it will be noted that the live center is indicated as being on signifying that each can is held tightly against its rotatable support 46. Also, during the drying and baking portion of the cycle the can is rotated by its rotatable support 46 due to its associated pulley 52 engaging the belt-like member 215.
At the completion of the baking period, cool air, which may be room temperature air, is supplied simultaneously to the outside and the inside of each can and while each can 21 is rotated during its orbiting movement, cool air is supplied to both the outside and inside of each can for a time interval of approximately two seconds and in the cooling zone designated C. After two seconds of outside cooling, cool air under pressure is maintained to the inside of each can 21 and at this point the can has moved away from the belt-like member whereby it stops rotating.
The outside cooling of each can 21 is completed after an elapsed time of approximately six seconds; however, as mentioned above the cool air to the inside of each can is continued and for approximately an additional second. The inside cooling air is provided at high pressure and velocity and propels each can into the discharge chute 210 as illustrated in FIG. 15.
Thus, it is seen that drying, baking, and cooling of each can 21 is achieved in a time interval of roughly seven seconds. Further, it will be seen that the apparatus 20 utilizes a minimum number of mechanical assemblies 90 and steam valves 152 in providing such high speed drying of cans.
While present exemplary embodiments of this invention, and methods of practicing the same, have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.
What is claimed is:
1. An apparatus for drying coating means applied against an exposed surface of a workpiece made of a heat conductive material, said apparatus comprising, a supporting device supporting said workpiece while maintaining said coating means substantially intact, and means heating the inside surface of said workpiece causing heating of said workpiece and causing heat to be conducted therethrough toward said exposed surface to dry said coating means from its inner surface outwardly to its outer surface to thereby provide high speed drying of said coating means and provide a dried coating means of improved quality.
2. An apparatus as set forth in claim 1 in which said heating means comprises a steam supply conduit and a steam spray head operatively connected to said steam supply conduit and arranged adjacent said inside surface, said 14 spray head ejecting steam against said inside surface to provide flash heating of said inside surface and of said workpiece.
3. An apparatus as set forth in claim 1 in which said workpiece comprises a tubular wall of a metal can and said heating means comprises a heating assembly arranged within and adjacent the inside surface of said tubular wall and in spaced relation therefrom.
4. An apparatus as set forth in claim 3 in which said heating assembly comprises a steam spray head operatively connected to an associated steam supply conduit, said spray head ejecting steam against said inside surface to provide flash heating of said inside surface and of said tubular wall.
5. An apparatus as set forth in claim 4 and further comprising a device for moving said ejected steam away from said inside surface.
'6. An apparatus as set forth in claim 1 in which, said workpiece comprises a metal can having a bottom wall and a tubular side wall adjoining said bottom wall and terminating in an end edge defining an open end for said can, said exposed surface of said workpiece being defined by the outside surface of said side wall which has said coating means applied thereagainst, said supporting device comprises an annular sealing member and a holding member engaging the bottom of said can and holding said end edge in sealed relation against said annular sealing member, said heating means comprises a steam supply conduit and a steam spray head operatively connected to said steam supply conduit and extending in sealed relation through said annular sealing member to enable flash heating of said side wall, said steam spray head being arranged adjacent the inside surface of said side wall and spaced therefrom, and vacuum means for evacuating ejected steam from the inside of said can after said flash heating of said side Wall.
7. An apparatus as set forth in claim '6 and further comprising a device for flowing air over the outside surface of said can during the drying of said coating means by said heating means to carry away gaseous impurities expelled from said coating means during the drying thereof.
8. An apparatus as set forth in claim 6 and further comprising an device for flowing heated air over the outside surface of said can following the drying of said coating means to bake said coating means on said tubular side wall.
9. An apparatus as set forth in claim 8 and further comprising means cooling said can and its baked coating means to enable subsequent handling of said can without scuffing said coating means.
10. An apparatus for high speed drying of coating means applied against exposed surfaces of a plurality of tubular wall means comprising, a rotatable wheel, a plurality of spaced supporting devices carried by said wheel for continuous orbiting movement, each of said supporting devices supporting an associated tubular wall means, and means heating the inside surface of each tubular wall means during continuous orbiting movement of said tubular wall means by said wheel, said heating means causing heat to be conducted through each tubular wall means to dry said coating means from its inner surface outwardly to its outer surface to provide a dried coating means of high quality.
11. An apparatus as set forth in claim 10 in which each of said supporting devices is arranged adjacent the outer periphery of said Wheel and further comprising an air supply system for flowing air at controlled temperatures about the outer surfaces of said tubular wall means during orbiting movement thereof, said air being used to assure the provision of said dried coating means of high quality.
12. An apparatus as set forth in claim 11 in which said air supply system provides high velocity air for carrying away gaseous impurities expelled from said coating means during the drying thereof, provides heated air around the