US2925062A

US2925062A - Coating apparatus

Info

Publication number: US2925062A
Application number: US614651A
Authority: US
Inventors: Schwindt Johannes
Original assignee: WC Heraus GmbH and Co KG
Current assignee: WC Heraus GmbH and Co KG
Priority date: 1953-05-15
Filing date: 1956-10-08
Publication date: 1960-02-16
Anticipated expiration: 1977-02-16

Description

Feb. 16, 1960 J. SCHWINDT comma APPARATUS Filed Oct. 8, 1956 2 Sheets-Sheet 1 IN VEN TOR. JOHA NNES S C HW/NDT BY m,mm

A T TOPNEKS- Feb. 16, 1960 J. SCHWINDT comma APPARATUS 2 Sheets-Sheet 2 Filed Oct. 8. 1956 INVEN TOR. JOHANNES" SCI IWINDT m ww A TTORNE )"5 W, WwM-B M,

COATING APPARATUS Johannes Schwindt, Langendiebach, Kreis Hanan, Germany, assignor to W. C. Heraeus, G.m.b.H., Hanan, Germany, a German company Application October 8, 1956, Serial No. 614,651

Claims. (Cl. 118-49) This invention relates to vacuum coating, and more particularly to apparatus for vacuum'coating' elongated strip material which can be rolled on and off storage reels.

Originally, in the continuous uninterrupted coating of strip material, such as long sheets of plastic, metal, paper, and cloth, by evaporation or by cathode sputtering of a metal or dielectric material, the roll of material to be coated was loaded directly into a high vacuum chamber where the coating operation was performed. This procedure suflered from the'disadvantage that each time a new roll was introduced, the coating chamber had to be vented to the atmosphere and then re-evacuated. Such a. procedure required an extraordinarily long time for evacuation, and adversely affected the economy of the operation. To avoid this difiiculty, it was subsequently proposed that the uucoated, as well as the coated, roll of material be located outside the coating chamber, and the strip material be introduced and removed through small slits leading into and out of the coating chamber. To compensate for the great pressure difierence between the outer atmosphere and the pressure in the vacuum chamber, a series of vacuum locks are used to provide stepwise decreasing pressures' However, this arrangement results in the loss of compactconstruction which is detrimental to the commercial and practical value of the system. In addition, the size of the slits of the previous equipment have not been readily adjustable to accommodate various conditions which may be subject to wide variation, such as varying thickness of the sheet material which is to be coated, and the different pressures which may be required to establish the necessary vacuum for the coating operation.

The present invention provides vacuum coating apparatus for strip material which is compact, of economical construction, and easily operated under a wide variety of conditions.

Briefly, the invention contemplates apparatus for vacuum coating strip material which includes a vacuum coating chamber having an inlet and an outlet. Means are provided for moving the strip material into the coating chamber throughthe inlet and out of the coating chamberthroughthe outlet. A separate series of vacuum locks are connected to the coating chamber inlet and outlet, and means are provided for forming a slit at each end of the locks through which the strip material passes.

2,925,062 a Patented-Feb. 15,1960

These and other aspects of the invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a schematic sectional elevation showing the presently preferred embodiment of the invention; and

Fig. 2 is a schematic sectional elevation of an alternate embodiment of the invention.

Referring to Fig. l, the coating apparatus includes a horizontal cylindrical storage chamber 12, and a horizontal cylindrical intermediate chamber 14 disposed below and in the same vertical plane as the storage chamber. A- vertical conduit15 of square cross section connects the.

intermediate chamber to the storage chamber. The storagechamber includes a bottom half 16 and a top half 17 which are held together by bolts 18 and flangesv A horizontal cylindrical coating chamber 20 is disposed immediately below and in the same vertical plane as the intermediate chamber and is. connected to the intermediate chamber by a short duct 21 of square cross section. The coating chamber-is connected through a valve 22 to a high vacuum system 24 which includes a difiusion pump 26 and a fore-vacuum pump -28. Thestorage chamber,

is connected through a valve 30 to a vacuum pump31.

A double-walled rotatable guide cylinder 32 is coaxially supported within the intermediate chamber by suitable journals (not shown) and spaced therefrom so that an annular space 33 is formed between the intermediate chamber and the guide cylinder. Four equally angular spaced and radially extending electromagnets 34 are disposed within the rotatable guide cylinder with their inner" I cylindermay be heated or cooled. as required.

Theaniiulzir space between the intermediate chamber and the; "g'uidecylinder on the left-hand side (as viewed in Fig. l) of the apparatus is divided into two inlet lock chambers 40 by three radially extending inlet lock gates 42, each of which is attached at its outer end to the inside surface of the intermediate chamber. Preferably, each lock gate includes a partition 44 which is a relatively thick and still but resilient strip of flexible material such as rubber. Each partition extends for the length of the intermediate cylinder and is suitably sealed against the ends of the intermediate chamber. Each partition is molded at its outer end to an elongated longitudinal boss 46 secured to the interior of the intermediate chamber. The inner end of each partition is covered by a metallic shoe 48 whichhas a concave curvature to match the Means exterior ofthe locks are provided for adjusting the size of the slits so that the clearance between the slits and the strip material moving through them may readily tight conduit means, through which the strip material are provided forl evacuating the storage passes, and means chamber. '5

periphery of the guide cylinder. A separate thrust rod 50 extends radially through the intermediate chamber and each boss and partition, so that the inner end of each thrust rod bears a'gainst. a respective shoe. The portion of each rod passing through its respective boss is threaded so that when the rod is turned by means of a handle 52 attached to its outer end, the length of the partition may be changed to adjust the spacing between the shoe and the periphery. of the guide cylinder. Thus, the shoe on the inner end of each inlet partition forms an adjustable inlet slit 53 with an adjacent portion of the guide cylinder;

Two outlet lock chamber 54 are formed in the annular space between the intermediate chamber andthe guide" cylinder on the right-hand side'of the apparatus by three outlet lock gates 56 which are constructed in the sameof the apparatus shown in Fig. 1. Each lock gate of the apparatus of Fig. 2 includes a fixed vertical lower partition 150 which extends across the duct in a direction perpendicular to the direction of travel of strip material. The fixed partition is bonded at its lower edge to the bottom of the duct and at each end to the sides of the duct. The top edge of the fixed partition terminates just below the center of the duct.

A flexible and adjustable vertical upper partition 152 is disposed in the upper portion of the duct to lie in the same plane as the fixed partition. The upper edge of the ductis bonded to a supporting bar 154 whch is sealed to the upper surface of the duct, and the side edges of the upper partition make a smooth and sealing fit against the sides of the upper portion of the duct. The lower edge of the upper partition has a protective metal shoe 156, which formsa narrow slit'158 with the adjacen por- -ion of the fixed partition.

An extension rod 159 extends down from the exterior of the top of the duct, through. the duct, throughthe supporting bar, and through the upper partition so thatthe lower end of the rod bears against the upper surface of the shoe. passes through the support bar so that when it is turned by means of a handle 160 attached to its upper end, it adjusts the length of the flexible partition, and thereby controls the size of the slit.

The supply and take-up chambers are evacuated by means of a pump 162 which is connected to the outer end of the inlet and outlet ducts by

conduits

164 and 165, respectively. The inlet lock formed between the two inlet lock gates nearest the supply chamber and the outlet lock formed between the two outlet lock gates nearest the take-up chamber are evacuated by a pump 168 connected to the inlet and outlet locks by conduits 170 and 172,.respectively. The inlet lock nearer the coating chamber and the outlet lock nearer the coating chamber are evacuated by a pump 174 through

conduits

176 and 178, respectively.

The coating chamber is evacuated through a main valve 180 connected to a diffusion pump 182 and a fore pump 184.

The operation of the apparatus of Fig. 2 is similar to that of Fig. 1. To place the apparatus of Fig. 2 into operation, the supply chamber is opened and a supply reel of strip material is inserted as shown in Fig. 2. The leading edge of the strip material is led from the supply reel over the first idling roller, through the first pair of guide rollers, and is guided by means of a metal strip attached to its leading edge through the inlet slits. Through suitable access ports (not shown), the strip is guided through the coating chamber and through the outlet slits. The strip is then threaded through the guide rollers in the take-up chamber, carried around the idler roller and connected to the take-up reel in the take-up chamber. The system is then made vacuum tight and evacuated to the required pressure.

Once the desired pressure is reached, the reels are actuated to pass the strip material through the coating chamber in the direction indicated by the arrows, the slits being adjusted to the necessary clearance to prevent excess leakage from one zone to another and yet provide sufiicient clearance to permit free passage of the strip material through the slit without danger of me chanical damage to the material.

When the strip material on the take-up reel is nearly exhausted, the inlet locks are closed against the strip material on the take-up reel. The supply chamber is then opened and the trailing end of the strip material is removed from the supply reel, which is replaced by a new supply reel with new strip material. The leading end of the new strip material is then cemented to the trailing end of the old strip material and the supply chamber is closed and evacuated. The new material is pulled through the apparatus by the old material, the slits The extension rod is threaded where it.

being adjusted to the necessary width. When the new material is in the take-up chamber, the exit slits are closed and the take-up chamber is open. The old material is cut from the new, and the leading end of the new material is connected to a new take-up reel, which replaces the old take-up reel. The take-up chamber is then again closed and evacuated, and the exit slits are adjusted to the proper size. The operation then proceeds as previously described. 1

With the apparatus of this invention, the evacuation of the strip material is sufliciently good, and the move ment of the strip material through the coating chamber is sufliciently low, to avoid the possibility of evolved gas being trapped during the winding of the strip material on the take-up reel to form air pillows or pockets which would result in a slippage of individual layers of strip material over each other, resulting in possible damage to the coating.

Another advantage of the apparatus of this invention is that it is of compact construction and requires only a limited working space without sacrificing facility of operation and inspection. In particular, the controls-for the lock gates are readily accessible from the exterior of the apparatus and can be adjusted during the operation of the apparatus, so that the sizes of the slits can be adapted not only to the thickness of the sheet material but also according to the required pressures. Moreover, as soon as a sufficiently high vacuum is produced in the apparatus, the sizes of the slits can be made larger in the high vacuum range (due to the relatively low rate of gaseous flow through narrow slits at low pressure) so that the danger of damaging thesurface of the strip material is substantially reduced. Moreover, the adjustability of the slit sizes permits the strip material to be changed without disturbing or interrupting the high vacuum in the coating chamber.

I claim: r

1. In apparatus for vacuum coating strip material, the combination which comprises a vacuum chamber having an inlet conduit and an outlet conduit, each of said conduits having at least one lock chamber, means for moving the strip material into the coating chamber through the inlet lock chamber and out of the coating chamber through the outlet lock chamber, at least one adjustable partition disposed in each of the inlet and outlet conduits for each lock chamber so that each partition defines one side of a respective slit through which the strip material passes, a separate adjustable extension rod sealed through each of the conduits and attached at its inner end to a respective partition to provide means for moving its respective partition toward and away from the strip material, means for evacuating the coating chamher, and means for introducing a vaporized coating material into the coating chamber.

2. Apparatus according to claim 1 in which the partitions are made of an elastic material, a shoe is attached to the portion of the partition which defines one side of the slit, and the extension rod extends through the partition so that the inner end of the rod terminates adjacent the side of the shoe attached to the partition.

3. In apparatus for coating strip material, the combination which comprises a storage chamber, an intermediate chamber, a first duct connecting the storage and intermediate chambers, a coating chamber, a second duct connecting the intermediate and coating chambers, a guide cylinder disposed within and spaced from the walls of the intermediate chamber, a plurality of adjustable partitions attached to the interior of the intermediate chamber and extending inwardly to terminate adjacent the guide cylinder so that a slit is formed between the inner portion of each partition and the adjacent portion of the guide cylinder, the partitions being disposed to divide the space between the guide cylinder and intermediate chamber into locks which isolate the ducts from means exterior of the intermediate chamber for moving the partitions toward and away from the guide cylinder, means forevacuating the cylinders, and means for introducing a vaporized coating material into the coating chamber.

4. Apparatus according to claim} in which the guide cylinder is rotatable.

5. Apparatus according to claim 4 which includes a plurality of electromagnets disposed within the guide cylinder and adapted to attract magnetic material to the guide cylinder.

6. Apparatus according to claim 3 which includes means for generating a revolving magnetic field'in the intermediate chamber.

7. In apparatus for coating strip materia l, the cornbination comprising a supply chamber, a coating chamber, an inlet duct connecting the supply and coating chambers, a take-up chamber, an outlet duct connecting the coating and take-up chambers, means for moving the strip material from the supply chamber through the inlet duct, the coating chamberQthe outletduct, and into the take-up chamber, a separate set of lock gates in the inlet and outlet ducts, the gates having adjustable openings through which the strip material passes, means exterior of the ducts for adjusting the size openings of the lock gates, means for evacuating the chambers, and means for introducing a vaporized coating material into the coating chamber.

8. In apparatus for vacuum coating strip material, the combination whichcomprises a vacuum coating chamber having an inlet and an outlet, means for moving the strip material into the coating chamber through the inlet and out of the coating chamber through the outlet, a separate series of locks connected to the coating chamber inlet and outlet, means forming a slit in each of the locks through which the strip material passes, means exterior of the locks for adjusting the size of the slits, means for evacuating the coating chamber, means for introducing a vaporized coating material into the coating chamber, a storage chamber for the strip material, and vacuum tight conduit 8 means connecting the storage chamber to the coating. chamber. V

9. In an apparatus for vacuum coating strip material, 5 the combination which comprises a vacuum coating chamber having an inlet and anoutlet, means for moving the strip material into the coating chamber through the inlet and out of the coating chamber through the outlet, a separate series of locks connected to the coating chamber inlet and outlet, means forming a slit in each of the locks through which the strip material passes, an adjustable extension rod connected individually to each of said slit-forming means for adjusting the size of the slits, each of said extension rods extending to the exterior of the locks, means for evacuating the coating chamber and means for introducing a vaporized coating material into the coating chamber.

10. In an apparatus forvacuum coating strip material, the combination which comprises a vacuum chamber having an inlet conduit and an outlet conduit, means for moving the strip material into the coating chamber through the inlet andout of the coating chamber through the outlet, at least one adjustable partition disposed in each of the inlet and outlet conduits so that each partition defines one side of a respective slit through which the strip material passes, a threaded extension rod sealed through each of the conduits and attached at its inner end to a respective partition whereby when the extension rod is turned the partition connected thereto will move toward or away from the strip material, means for evacuating the coating chamber and means for introducing a vaporized material into the coating chamber,

References Cited in the file of this patent UNITED STATES PATENTS"