US3356064A

US3356064A - Installation for coating paper and like sheets with varnish and the like

Info

Publication number: US3356064A
Application number: US525555A
Authority: US
Inventors: Bush Thomas Burrow; Bush Henry Norman
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-02-11
Filing date: 1966-02-07
Publication date: 1967-12-05
Anticipated expiration: 1984-12-05
Also published as: GB1122861A

Description

INSTALLATION FOR COATING PAPER AND LIKE Dec. 5, 1967 T. B. BUSH ETAL 3,356,064

- SHEETS WITH VARNISH AND THE LIKE Filed Feb. 7, 1966 8 Sheets-Sheet 1 F/G IA INVENTOR:

QZ M Z Hr M r Dec. 5, 1967 Filed Feb. 7, 19 66 INSTALLATION FOR COATING PAPER AND LIKE SHEETS WITH VARNISH AND THE LIKE T. B. BUSH ETAL 8 SheetsSheet 2 INVE NTOR:

BY MAMQ.

Dec. 5, 1967 T. B. BUSH ETAL INSTALLATION FOR COATING PAPER AND LIKE SHEETS WITH VARNISH AND THE LIKE 8 Sheets-Sheet 5 Filed Feb. 7, 1966 INVENTOR:

THOMAS 8.305'1'4 HGNRYN'BUSH Dec. 5, 1967 T. B. BUSH ETAL INSTALLATION FOR COATING PAPER AND LIKE SHEETS WITH VARNISH AND THE LIKE 8 Sheets-Sheet 4 Filed Feb. 7, 1966 INVENTOR: THOMRS Bfius/I 4 HEuRYN-BUSH Dec. 5, 1967 T. B. BUSH ETAL INSTALLATION FOR COATING PAPER AND LIKE SHEETS WITH VARNISH AND THE LIKE 8 Sheets-Sheet 5 Filed Feb. 7, 1966 INVENTOR: THOMAS B-BUSH4 new/2y /v. 1305 BY I d LMAQM 4.

R-rro a 8 Sheets-Sheet 6 l IIHR SHEETS WITH VARNISH AND THE LIKE INSTALLATION FOR COATING PAPER AND LIKE Dec. 5, 1967 Filed Feb. 7, 1966 INVENTOR: um/m5 3.30s; u'elvfiwv-fi'usl/ M ume? E BY am 4.

)IllIlIlHIIK J l Dec. 5, 1967 BUSH ETAL 3,356,064

INSTALLATION FOR COATING PAPER AND LIKE SHEETS WITH VARNISH AND THE LIKE Filed Feb. 7, 1966 8 Sheets-Sheet 7 INVEINTOR: THOMAS E. su'sHq H NRy/V- 50s fMj J- M Dec. 5, 1967 T. B. BUSH ETAL 3,356,064

INSTALLATION FOR COATING PAPER AND LIKE SHEETS WITH VARNISH AND THE LIKE Filed Feb. '7, 1966 8 Sheets-Sheet 8 THOMA B-BusH 1 HENRY N- gas BY I ATTORN INVENTQR:

United States Patent 5 Claims. (Cl. 118-66) ABSTRACT OF THE DISCLOSURE An installation for applying coating material to separate paper sheets comprising a coating machine into which the separate sheets are passed between a backing cylinder and a coating applying means together with an endless gripper conveyor for taking successive coated sheets into an oven dryer from which the dried sheets are conveyed to a cooling tunnel.

This invention relates to an installation for applying liquid varnish or lacquer, plastic lacquer or like rapiddrying coating materials to the surface of paper or like sheets, that is separate sheets such as are fed into a coating machine by releasable grippers, as opposed to long lengths of paper or the like which can be drawn through the machine from a feed roll of the paper.

The present invention concerns an installation which embodies a coating machine constructed and arranged to operate as disclosed in one or other of the specifications of our British Patents Nos. 852,489 and 950,908, current series in which machine the separate sheets are passed between the backing cylinder and a varnish-applying roller with the latter rotating in a reverse surface direction relative to that of the cylinder. This reverse-roller coating process as applied to separate sheets enabled a thicker coating and one with a much glossier finish to be produced without the ribbing or longitudinal marking of the paper surface which usually resulted when attempts were made to apply more varnish with conventional machines.

The varnished sheets produced by the machines of our said prior patents have an extremely high quality finish and a thicker coating than usual and consequently call for improved techniques in their handling and drying on leaving the coating machine. It is an object of the present invention to provide an improved installation for this purpose.

The installation according to the invention includes a coating machine of the indicated kind, means for feeding separate sheets to the cylinder grippers of such machine, an endless take-off gripper conveyor for taking the successive coated sheets from said cylinder and conveying them by its lower stretch, a tunnel oven or dryer having a series of radiant heaters or having hot air blowing provision, an endless oven gripper conveyor for taking the successive sheets from said take-01f conveyor and conveying them on its upper stretch through said oven, a cooling tunnel having an endless cooling gripper conveyor for taking the successive sheets from said oven conveyor and conveying them by its lower stretch through the cooling tunnel supported on an openwork apron, and means for delivering said sheets from said cooling conveyor.

The whole installation is arranged to be driven and controlled so as to ensure proper drying of the coated sheets before they are stacked or piled together, and may include manual or automatic control mechanism and devices to achieve this purpose. For example, they may be hermostatic and/ or timer control of the oven tempera- 3,356,064 Patented Dec. 5, 1967 ture which may vary in different parts of the oven, although the sheets will travel through the installation at a speed governed by that of the coating machine. This speed can be high compared with conventional machines due to the positive gripper control on the sheets throughout, and due to the efiicient and uniform drying and subsequent cooling. The cooling is preferably produced by air jets issuing from two sets of cooling pipes above and below the sheets.

Whilst radiant heaters such as those of the ceramic type arranged above the travelling sheets are very suitable for use in the tunnel oven or dryer of this invention and their use is herein described and illustrated by Way of example, it is to be understood that other suitable forms of drying provision may be used. In particular, it may be found more advantageous to use what is termed in the art high velocity air blast drying. This system is well known in the paper conditioning trade for treating continuous paper webs and consists in blowing heated air by a high velocity in downwards over the travelling sheets and withdrawing and recirculating the air.

In order that the invention may be fully and clearly comprehended, the same will now be described with reference to the accompanying drawings, which illustrate one form of installation and wherein:

FIGURES 1A, 1B and 10 represent jointly a schematic side elevation of the installation showing the general layout;

FIGURE 2 represents on a larger scale a side elevation of the coating machine, the takeoff conveyor and the adjacent receiving end of the oven conveyor;

FIGURE 3 represents in end elevation, as seen in the direction of arrow X in FIGURE 1A, the driving connections to the coating machine and take-01f conveyor, other features irrelevant to the driving means being omitted;

FIGURE 4 shows an end elevation (with portions in section) of the driving and control mechanism for the receiving end of the oven conveyor;

FIGURE 5 represents a vertical section, taken mainly on the line VV in FIGURE 4, of the oven conveyor at its receiving end, showing the means for gripping and supporting the coated sheets; v

FIGURE 6 is a section taken on the line VIVI in FIGURE 5 showing how said means for supporting the 45' sheets is mounted on the oven conveyor;

FIGURE 7 is an enlarged sectional view of one of the gripper devices on the take-off conveyor; and

FIGURE 8 represents a plan of the cooling and delivery end of the installation shown in FIGURE 1C, the overhead exhaust ducting being omitted.

Referring first to the general lay-out of the installation as illustrated by FIGURE 1, a sheet-feeder A is arranged to feed the paper sheets one at a time to the cylinder grippers of a coating machine B. The sheets are then transferred to the grippers of a take-off conveyor C which in turn transfers them to the grippers of an oven conveyor which carries them through a tunnel dryer or oven D. On emerging from the oven the sheets are again transferred to the grippers of a cooling conveyor which carries them through a cooling tunnel E and releases them to a sheet deliverer F. These parts of the installation will now be described in order.

The sheet feeder A may be of any suitable kind but is illustrated as a pile feeder having a frame 1, a table top 2, a sheet platform 3 which can be raised progressively by chains or cables 4 carried over wheels 5 to maintain the top sheet of the pile at the table level, and means driven by a belt 6 for feeding the sheets S successively at predetermined intervals over support table 7 to the coating machine B. Such a sheet feeding machine is well known and needs no further description.

The coating machine B (or varnisher as it will be called) has a frame 8 supporting a rotatable cylinder 9 between the ends of which is carried a rockable gripper shaft 10 (see FIGURE 2). This shaft carries a series of grippers 11 spaced apart along the shaft and as the cylinder rotates in the direction of the arrow the grippers are caused by known cam mechanism to grip the leading edge of the sheet on table 7 and carry it past the varnish trough 12 where the contra-rotating varnish-applying roller 13 coats it with varnish. When the gripper bar 10 reaches the position indicated in dot-and-dash lines in FIGURE 2, the grippers are caused to release the sheet in known manner and its leading edge is simultaneously gripped by another .set of grippers on the take-off conveyor C.

This conveyor as shown in FIGURES 2 and 3, is of the endless chain type having two chains 14 carried

round wheels

15, 16 supported in a casing 17. This conveyor carries two transverse gripper bars 18 (omitted from FIG- URE 3) and as shown in FIGURE 7 each bar has a rockable shaft 19 on which are secured a series of grippers 20 which are spaced along the shaft so as to correspond in position with the spaces between the grippers 11 on the varnisher cylinder. The shaft 19 carries an arm 21 with a runner 22 arranged to engage an adjustable timer cam 23 to close the grippers towards a rubber or like pad or pads 18X so as to grip the leading edge of the sheet S as it is released by the grippers 11 and trail the sheet along the openwork bottom of casing 17. A similar timer cam (not shown) opens the grippers to transfer the sheet from the bottom stretch of the conveyor C to the top stretch of the oven conveyor.

The means for driving the mechanism so far described is as follows. An electric motor 24 drives, through suitable speed-varying mechanism a pulley 25 which through belt 26 and pulley 27 drives shaft 28, and this shaft transmits the drive through pulley 29, belt 30 and pulley 31 to shaft 32 on which is secured a pinion 33 driving gear wheel 34 secured on the shaft 35 of the varnisher cylinder 9. The belt 6 for driving the sheet feeder is also driven from shaft 32. The belts and pulleys will be of the positive drive type, or chains and chainwheels may be used instead, to ensure that the parts are driven at definite known speeds because this is essential to enable the take-off conveyor to co-operate accurately with the varnisher roller and the oven conveyor in order to ensure a smooth passage of the coated sheets.

The oven D is of thetunnel-dryer type and consists of a long casing 36 (say long) with side channel members 37 mounted on legs 38 and having sets of ceramic or other radiant heating elements 39 supported above the oven gripper conveyor. These elements may be of different power in different sections of the oven. The conveyor consists of two endless chains 40 carried round pairs of

wheels

41, 42 and supported along their lengths in channel or other guides, this arrangement being well known and requiring no further description. These chains carry between them a series of gripper bars 43, and each gripper bar has pivotally mounted upon it a row of grippers 44, these grippers being spaced apart so as to co-operate with the grippers 20 on the take-off conveyor and to act between the latter during transfer of each sheet to the top stretch of the oven conveyor. The grippers are opened and closed by devices (not shown) similar to the timer cam 23 described with reference to the take-off conveyor C.

We have found that in transferring thesheets from the grippers of the take-01f conveyor, which runs at the same surface speed as that of the cylinder of the coating machine, to the grippers of the oven conveyor, which runs at a lower speed than that of the take-off conveyor, it is difiicult to ensure uniformity in the amount of sheet edge which is gripped by the oven grippers. The sheet edges each have an uncoated strip which may be Wide and on which the gripper should bite, but owing to the difference in speeds of the two conveyors and the momentum of the sheets at the moment of transfer the oven grippers may grip beyond the uncoated strip. This would result in wet coating material being transferred onto the gripper faces, thus spoiling the sheets and necessitating cleaning of the gripper faces.

In order to overcome this difficulty each gripper bar 43 is fitted on its rear face with a number of stops 45 located (say) back from the gripper edges so that the front edges of the sheets, once they have engaged the stops, will not move relatively thereto when being gripped and will only begripped by their uncoated edges. The stops are suitably spaced along the bars, say eight on each bar, and each one is preferably located close beside a gripper to minimise undesirable movement of the sheet edge against the stops during gripping and releasing of the sheets. If desired these stops may be faced with or formed from a softer material than metal to reduce the chance of their marking the front edges of the sheets.

The manner in which the sheets are supported when being conveyed through the oven is also very important for high quality products. If the sheets are gripped at the leading edge and allowed to trail along a smooth sheet metal floor, they may dry with an undesirable curvature, the metal floor may become overheated, and (most important) some parts of the sheets will be supported nearer to the overhead heaters than others and uneven drying will result.

In order to overcome this difficulty, we provide a series of flexible aprons 46 supported from the chains 40 between adjacent gripper bars 43 so as to extend substantially horizontally and to form supports for the sheets during their passage through the oven. These aprons may be of hessian or other fibrous fabric or of any other flexible material which will Withstand th heat, and are preferably of openwork structure to reduce their tendency to overheating. These aprons can be quite cheap and can easily be attached at their front and rear edges by passing rods 47 through the looped ends of the aprons and securing the rod ends to brackets 48 mounted on the chains 40 as clearly shown in FIGURES 5 and 6, so that the aprons extend approximately in line with the gripping surfaces of the bars 43 and grippers 44. By thus supporting the sheets substantially parallel to the plane of the heaters 39 a much more uniform drying effect may be obtained. Rollers 49 mounted between the conveyor wheels 41 and 42 (see FIGURE 5) control the aprons at each end of the conveyor.

The cooling tunnel E (FIGURES 1C and 8) has a casing not shown in the drawings and through this extends a cooling conveyor which may be of a similar construction to that of the take-off conveyor C but much longer. Two endless chains 50 are carried around

wheels

51, 52 mounted between the ends of frame members 53, and-these chains carry sets of grippers on gripper bars 54 (omitted from FIGURE 8) which may be similar to those on the oven conveyor and which grippers are arranged to be opened and closed also in similar fashion. The grippers on the bottom stretch of the cooling conveyor drag the sheets by their leading edges across a stationary openwork apron 55.

Within the cooling tunnel and extending across and a short way above the bottom stretch of the conveyor are banks of cooling pipes 56, and just below this stretch are further banks of cooling pipes 57, all these pipes being perforated at closely spaced intervals with holes of a suitable size or of different sizes (e.g. diameter spaced at 1" centres) arranged to direct jets of cooling air onto the passing sheets S at suitable angles and with suitable force, but not sufiicient to disarrange the sheets nor to disturb the smooth surface of the coating. Each bank of pipes is secured to a manifold 58 which communicates by a duct 59 having an adjustable bafiie 60 with a main duct 61 to which cooling air is supplied by a fan 62 driven by a motor 63. Air at ambient room temperature is preferred for cooling, but if desired the air fed to

pipes

56, 57, may be drawn through a cooling device of any suitable kind.

In order to enable the cooling jets to be directed against the sheets at the angle best suited to the nature of the sheets and the coating medium being used at any particular time, the

pipes

56, 57 ar preferably attached to the manifolds by flexible or rotary couplings which will enable some or all of the pipes to be turned through desired angles, and these couplings will be easily disconnectible to enable other pipes with ditferent perforations to be substituted. This arrangement in conjunction with the speed of the conveyor will enable a very accurate control to be exercised over the degree and nature of the cooling action, and has an important bearing on the quality of the surface finish of the sheets.

The sheet deliverer F may be of any suitable kind but is illustrated as a pile deliverer operating in the reverse way to the feeder A. It has a frame 64 supported on legs 65, and a receiving table 66 can be slowly lowered as the dried sheets are deposited upon it successively to form a pile in the normal manner of such deliverers. The lowering mechanism in casing 67 can be of any suitable kind and can be driven independently of the rest of the installation at a predetermined speed or can be driven from the cooling conveyor. The frame and drive casing are omitted from FIGURE 8 for clarity, but FIGURE 1C shows how the cooling conveyor 50 extends over the deliverer F and draws each sheet in turn off the end of the apron 55 onto the table 66 and then releases it.

The casings of the take-off conveyor and oven conveyor are provided with outlet ducts 94 having separately adjustable baffles 95 and communicating with a common trunking 96 leading to an extraction fan 97 driven by an electric motor 98, the fan and motor being mounted on a support 99 upon the frame members 53 of the cooling conveyor. This extraction system removes fumes from the neighbourhood of the oven and take-off conveyors and, if so arranged, of the varnisher.

The main drive for the installation is from motor 24 through gear 34 to gear 70 secured on the shaft of wheels which drive the take-01f conveyor (see FIGURE 3). Wheels 16 of this conveyor then drive through spur gears 71, '72 and 73 a spur gear 74 which, during normal running of the installation, is connected to drive the shaft on which are secured the wheels 41 carrying the oven conveyor 40. This conveyor in turn, through its wheels 42 and a train of spur gears 75, 76, 77, 78 (shown only in FIGURE 1C), drives the cooling conveyor 50 at the same speed. Thus the travelling movements of the grippers on the three conveyors are correctly synchronised.

It has been mentioned above that the oven conveyor 40 runs at a lower speed than that of the take-off conveyor 14, the distance between adjacent gripper bars being different in the two cases to permit the transfer of sheets to take place. This differential speed is very desirable because on the conveyor 14 the successive sheets are (say) 30" apart as they come off cylinder 9, whereas it is desirable that they should follow one another closely through the oven to achieve the maximum drying time within a minimum length of oven.

A further feature of the driving and controlling mechanism of the installation is illustrated particularly in FIG- URES 1, 2 and 4. The gear 74 is freely mounted about the shaft on which conveyor wheels 41 are secured but is normally connected thereto by a dog clutch 80 keyed or otherwise slidably secured to the shaft to rotate with it, the dog teeth being adapted to engage in recesses in the face of gear 74. The clutch is always drivably connected to a bevel gear 81 in engagement with a bevel gear 82 on a long drive shaft 83 which is supported at intervals from the channel members 37 and which carries at its other end a bevel gear 84 engaging a bevel gear 85 secured on the shaft of the conveyor wheels 42. The projecting end of drive shaft 83 is coupled through a one way clutch of any suitable kind and through pulleys 86, 87 and belt 88 with an electric motor 89. This motor can be started and stopped by operation of a switch 90 actuated by a pivoted handle 91 which is connected through rod 92 to a clutchoperating lever 93.

These driving connections provide a positive drive for both ends of the oven conveyor which is very desirable in view of its length, but it also acts as an auxiliary drive for the purpose now to be described.

When starting up the installation, the auxiliary drive motor 89 and the overhead heaters 39 would be switched on first, with clutch disengaged and switch 90 held on by handle 91. The oven conveyor must be kept moving to prevent overheating of it and, in particular, of the aprons 46. When the oven has reached the predetermined temperature, the main drive motor 24 is started to drive the feeder, varnisher and take-off conveyor. The oven conveyor is then coupled to the main drive by operating lever 91 which through switch 90 stops the motor 89, the clutch 80 acting to synchronise the movements of the two conveyors to ensure correct co-operation between their two sets of gripper bars.

When stopping the installation, the auxiliary drive for the oven conveyor and cooling conveyor is first started by operating handle 91 and then the main drive motor 24 is stopped; or if desired, handle 91 may be arranged to actuate a further switch to stop and start motor 24, in which case stopping of the varnisher would automatically cause starting of the auxiliary drive. In any event, the auxiliary drive forms a safety device to ensure that the oven conveyor will continue to operate until all the sheets S are delivered from the oven, thus preventing possible damage to them by overheating and avoiding fire risks. It will also be arranged by suitable control devices of known kind to ensure that the oven conveyor keeps moving as long as the heaters are operating.

It will be noted that fire risks are minimised by the provision of the above-mentioned auxiliary drive arrangement, and also by the use of ceramic heaters located only above the travelling sheets whereby the sheets cannot fall on the heaters.

Whereas high velocity air blast drying could not previously be used for treating separate paper or like sheets in a tunnel oven or dryer because the blast would disturb the sheets and damage them, this system can be used in the present invention because of the novel manner in which the sheets are supported on the flexible aprons so as to be undisturbed by the downward blast. Also this drying system would further reduce the fire risks and would enable a shorter oven to be used owing to the greater drying efficiency.

Not only will the installation handle the full-width sheets for which the varnisher is designed, but the positive gripper control on all the conveyors enables narrower sheets to be handled in two or more streams side by side, the feeder and deliverer being provided with suitable attachments for this purpose as will be clear to those skilled in the art.

Whilst the hereinbefore described embodiments of the invention have been mentioned merely by way of example, it is to be understood that other suitable embodiments may be evolved for carrying out the invention and that protection is hereby claimed for all such embodiments within the scope of the appended claims.

We claim:

1. An installation for applying liquid varnish and like rapid-drying coating materials to the surface of a sequence of separate and unconnected paper and like sheets, which includes the combination of a coating machine having a cylinder with grippers thereon, means adjacent said cylinder for applying coating material, means for feeding separate sheets to said cylinder grippers, an endless take-off gripper conveyor for taking the successive coated sheets from said cylinder and conveying them by its lower stretch, a tunnel oven dryer having heated drying provision, an endless oven gripper conveyor for taking said successive sheets from said takeoff conveyor and conveying them on its upper stretch through said oven, a cooling tunnel having an endless cooling gripper conveyor for taking the successive sheets from said oven conveyor and conveying them by its lower stretch through said cooling tunnel,

means for delivering said sheets from said cooling conveyor, and means for driving and controlling said feeding means, said coating machine and all said gripper conveyors.

2. An installation including the combination called for in claim 1, and wherein said driving means includes a common power means for driving said coating machine and all said conveyors and also includes an auxiliary power means for driving said oven conveyor and cooling conveyor when said coating machine and take-off conveyor have been stopped, there being means for starting said auxiliary drive automatically when said common drive is stopped, and means for automatically synchronising the travelling movements of the grippers on the take-off conveyor and oven conveyor when these two conveyors are being connected to be driven from said common driving means.

3. An installation including the combination called for in claim 1, and wherein said oven conveyor carries transverse gripper bars each with a series of grippers thereon and also carries between each pair of adjacent gripper bars a flexible apron arranged to support a travelling coated sheet thereon in a substantially horizontal position, there being guiding means for controlling said aprons at each end of said conveyor.

4. An installation including the combination called for in claim 3 and further including sets of abutments on and spaced along each of said gripper bars and spaced rearwardly from the gripper edges so as to ensure that each sheet is gripped only by the uncoated strip along its leading edge.

5. An installation including the combination called for in claim 1 and including in said cooling tunnel means for directing a multiplicity of jets of cooling air against the upper and lower surfaces of the travelling sheets and means for varying the angle of impingement of said jets upon said sheets.

References Cited UNITED STATES PATENTS 3/1951 Belluche et al. 1188 7/1966 Dickerson 1l8209 X

Claims

1. AN INSTALLATION FOR APPLYING LIQUID VARNISH AND LIKE RAPID-DRYING COATING MATERIALS TO THE SURFACE OF A SEQUENCE OF SEPARATE AND UNCONNECTED PAPER AND LIKE SHEETS, WHICH INCLUDES THE COMBINATION OF A COATING MACHINE HAVING A CYLINDER WITH GRIPPERS THEREON, MEANS ADJACENT SAID CYLINDER FOR APPLYING COATING MATERIAL, MEANS FOR FEEDING SEPARATE SHEETS TO SAID CYLINDER GRIPPERS, AN ENDLESS TAKE-OFF GRIPPER CONVEYOR FOR TAKING THE SUCCESSIVE COATED SHEETS FROM SAID CYLINDER AND CONVEYING THEM BY ITS LOWER STRETCH, A TUNNEL OVEN DRYER HAVING HEATED DRYING PROVISION, AN ENDLESS OVEN GRIPPER CONVEYOR FOR TAKING SAID SUCCESSIVE SHEETS FROM SAID TAKEOFF CONVEYOR AND CONVEYING THEM ON ITS UPPER STRETCH THROUGH SAID OVEN, A COOLING TUNNEL HAVING AN ENDLESS COOLING GRIPPER CONVEYOR FOR TAKING THE SUCCESSIVE SHEETS FROM SAID OVEN CONVEYOR AND CONVEYING THEM BY ITS LOWER STRETCH THROUGH SAID COOLING TUNNEL, MEANS FOR DELIVERING SAID SHEETS FROM SAID COOLING CONVEYOR, AND MEANS FOR DRIVING AND CONTROLLING SAID FEEDING MEANS, AND COATING MACHINE AND ALL SAID GRIPPER CONVEYORS.