US 3850138 A
Substrate supporting discs are arranged to travel around a circular path and to rotate about their own axes during such travel. The discs are held spaced from each other by separating arms which are connected to each other. A separable ball and socket contact is formed between each separating arm and its associated substrate supporting disc. The separating arms and their interconnecting structure are supported by said discs and do not contact any other portion of the apparatus during operation. A freewheel drive mechanism permits easy rotation of the apparatus by hand when the drive motor is off.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Patono  Nov. 26, 1974 SUBSTRATE CARRYING APPARATUS FOR USE IN COATING EQUIPMENT Car-1o Luigi Patono, Turin, Italy Deposition Fixturing, lon Equipment Corp., 1805 Walsh Ave., Santa Clara, Calif. 95050, Copy received 1971.
Primary Examiner- -Morris Kaplan Attorney, Agent, or Firm-Stanley Z. Cole; Leon F. Herbert [S 7 ABSTRACT Substrate supporting discs are arranged to travel around a circular path and to rotate about their own axes during such travel. The discs are held spaced from each other by separating arms which are connected to each other. A separable ball and socket contact is formed between each separating arm and its associated substrate supporting disc. The separating arms and their interconnecting structure are supported by said discs and do not contact any other portion of the apparatus during operation. A freewheel drive mechanism permits easy rotation of the apparatus by hand when the drive motor is off.
7 Claims, 4 Drawing Figures Pmmmuvz 3,850,138
SHEET MP 2 SUBSTRATE CARRYING APPARATUS FOR USE IN COATING EQUIPMENT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is an improvement in the field of supporting and moving substrates in coating equipment.
2. Description of the Prior Art Apparatus has been provided in which substrate sup porting discs are arranged to travel around a circular path and to rotate about their own axes during such travel. However, the prior art devices have not solved the problem of providing movement of the discs in a simple and reliable manner. One reason the problem is difficult to solve is that the apparatus normally operates at high temperature and low pressure and in an atmosphere where coating material tends to coat all surfaces it can reach. All of these conditions make it difficult to create controlled movement of the discs and avoid intolerably high friction forces. Also the prior art devices which included properly geared down drive mechanisms are difficult to move by hand when the operator desires to reach a remote disc when the drive motor is off.
SUMMARY OF THE INVENTION The object of the invention is to provide a substrate carrying apparatus which overcomes the deficiencies of the prior art. More specifically an object of the invention is to provide controlled movement of the substrate support discs in a reliable and efficient manner which minimizes friction problems. Another object of the invention is to provide a drive mechanism which permits easy movement of the apparatus by hand in the motoroff condition.
The objects of the invention are achieved in a structure which comprises a circular driving track that supports the lower portion of each substrate supporting disc and causes the discs to rotate when the track is rotated. The upper portion of each disc rests on the rim of a support plate positioned concentrically above the track and of smaller diameter. The discs are held in place separated from engagement with each other by separating arms. The upper ends of the separating arms are interconnected with each other, and the lower end of each arm'has a ball and socket contact coaxial with its respective disc. During operation the arms and their interconnecting means do not engage any portion of the apparatus except the discs. A freewheel drive mechanism permits easy rotation of the driving track when the motor is off.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevational view, partly in section, showing the apparatus according to the invention;
FIG. 2 is a schematic view of the drive mechanism;
FIG. 3 is an enlarged cross section through the ball and socket connection between the separating arms and their respective substrate support discs; and
FIG. 4 shows a portion of FIG. I in which a modified separating arm is employed.
DETAILED DESCRIPTION OF THE INVENTION Referring in more detail to the drawings as shown in FIGS. l-3, the apparatus comprises a plurality of sub strate support discs 5 each containing a plurality of apertures 6 in which the substrates (not shown) are mounted in conventional manner. The embodiment shown in the drawings is designed for a total of three discs but more or fewer can be used within the scope of the invention. In the drawings only one of the three discs 5 is shown mounted in the apparatus. Each of the discs has a circular peripheral edge 7 which rests in a V-groove 10 which forms a driving track in the rim of a driving ring 11. The upper portion of each disc rests on the circular support surface 12 of a support plate 13 or the circular support surface 14 of a support plate 15.
The driving ring 11 is mounted to rotate with a driven ring 20 by means of at least three posts 21 secured to he two rings. Driven ring 20 is supported on at least three roller bearings 22 equally spaced around the ring 20. Throughout the description where reference is made to at least three items, such as bearings 22, less than three may appear in the drawing because of sectioning or because one item is behind another or for clarity of disclosure. Ring 20 is constrained to rotate about an axis concentric with its own axis by means of at least three equally spaced roller bearings 23 which engage the outer periphery of ring 20. The roller bearins are mounted on a base support ring 24 which is in turn supported on at least three posts 25, each having a leg 26 adapted for mounting on the underlying portions of a conventional coating system, not shown. As is well known by those skilled in the art, such conventional coating equipment includes a source of coating material such as a vapor source usually located on the axis of rotation of driving ring 11. Rings 11, 20 and 24, and plates 13 and 15 are all concentric with each other.
Ring 20 is driven by friction engagement with a drive wheel 27 which rotates on a horizontal axis. A conventional gear and bearing box 28 supports the drive wheel 27 and is mounted on the underside of base ring 24. Gear box 28 houses conventional gearing to convert rotation of a drive shaft 29 from the vertical axis of shaft 29 to the horizontal axis of drive wheel 27. As shown in FIG. 2, shaft 29 is driven by a motor 30 through a conventional speed reduction gear box 31 and thence through a conventional freewheel drive 32 and conventional universal joints 33. The freewheel drive 32 is an important aspect of the apparatus because it permits the operator to turn driving ring 11 by hand when the motor is off, so that the operator can reach a disc 5 which is on the opposite side of the vertical center of rotation of ring 11. Gear box 31 contains extremely high reduction gearing so that if it were necessary to turn the motor by hand via drive ring I1 and the reduction gearing, it would be extremely difficult. Thus it is important to have the freewheel drive 32 or similar mechanism which disconnects the gear box 31 from the driving ring 11 when the motor is off, and thus permits easy rotation of driving ring 11 by hand in the motor-off condition. It will be understood that the re duction gearing is directed such that shaft 29 turns much more slowly than the motor shaft.
Returning to the means for supporting'the discs 5, the support plates 13 and 15 are carried by at least three support arms 34 mounted on the base support ring 24. For clarity of disclosure the nearest arm 34 is not shown. A bolt 35 extends downwardly from the top of each support arm 34 and carries the support plate 15.
Support plate 13 is mounted from support plate 15 by means of at least three bolts 36 surrounded by spacing collars 37. A circular heat shield plate 38 is also mounted on bolts 35 by means of spacing collars 39 and 40.
The operation of the apparatus thus far described is as follows. Motor 30 turns the driving ring 11 in the manner previously described. The frictional engagement between the bottom of each disc 5 and the drive ring 11 causes the discs to move around the axis of the driving ring and also rotate about their own axes. In order to assure free and uniform rotation of the disc 5, it is necessary to hold the discs spaced slightly from each other so that frictional engagement between the discs does not hinder their desired movement. It is also desirable to bias the discs 5 slightly inwardly to prevent any tendency to move outwardly as they rotate around the axis of drive ring 11. According to the invention these objectives are achieved in a very simple and efficient manner as will now be described.
An apertured ring 42 is loosely positioned around bolts 35 above the support plate 15. In order to provide rigidity to the ring 42 it has a downwardly projecting rim 43 around the periphery of its central aperture. Spring metal separating arms 44 equal in number to the desired number of substrate support discs 5 are attached at their upper ends to the ring 42 and extend downwardly and radially outward therefrom in equally spaced arrangement. Each arm 44 is attached to the ring 42 by two short bolts 45. As shown in detail in FIG. 3, the free end of each arm 44 carries a threaded shaft 46 having a spherical ball 47 at its lower end. Shafts 46 are connected to their respective support strips by nuts 48. A socket member 50 is secured to each of the support discs 5 by welding or other suitable means and is provided with a spherical recess 51 preferably having a radius of curvature larger than the radius of curvature of ball 47. The socket members are adapted to receive the balls 47 to form in effect a ball and socket bearing. The socket members 50 are positioned so that the center of the recess 51 is coaxial with the center of its disc 5. When it is desired to remove a disc the operator simply flexes the strap shaped arm 44 outwardly and upwardly. The reverse operation permits the operator to insert a disc. When all of the discs 5 are removed, apertured ring 42 moves downwardly to rest on the heat shield 38.
The means for supporting discs 44 is adapted for use whether the discs 5 are positioned against the small diameter plate 13, as shown in FIG. 1 or are positioned against the larger diameter plate 15. One way of accomplishing the change and still assure that the axis of shaft 46 will be exactly coaxial with the axis of its associated disc 5, is to replace arms 44 with arms 44 by removing and replacing small bolts 45. As shown in FIG. 4, arms 44' are slightly longer than arms 44 and have an inwardly bent portion 53 at their lower ends.
It should be understood that when the apparatus is in operation theapertured ring 42 is not in contact with any other portion of the apparatus and is thus free to rotate without any frictional resistance. The ring .42 and arms 44 or 44 are supported entirely by the balls 47. This is important because. as is well known to those skilled in the art. conventional coating apparatus normally includes a heater located above support arms 34 to heat the substrates to a very high temperature for cleaning or stress relieving prior to deposition of the tremely detrimental to the functioning of normal bearings, particularly those which are located up near the heater as would be the case if apertured ring 43 were mounted on a bearing at its center. It should also be understood that the ball and socket contacts 47, 51 carry very little load and are not the conventional closed,
tight tolerance type of structure which is normally employed as a bearing. Therefore the ball and socket contacts are less subject to the binding effects of high temperature and low pressure atmosphere.
What is claimed is:
' 1. Apparatus for carrying substrates comprising means forming a circular driving track, a plurality of substrate supporting discs each having a circular rim supportable on said track, support means above said track having a circular support surface positioned so that when the lower portion of each said disc rests on said track the upper portion of each said disc rests against said support surface, means for rotating said track, positioning means for holding said discs in fixed spacial relation to each other as they travel around the axis of said track, said positioning means comprising a positioning arm for each of said discs, means interconnecting the upper ends of said arms, a first bearing contact surface on the lower portion of each of said arms, a second bearing contact surface on each of said discs and engageable by one of said first bearing contact surfaces, said first bearing contact surfaces being disengageable from said second bearing contact surfaces by outward movement of said first bearing contact surfaces relative to said second bearing contact surfaces, said arms being flexible in an outward direction to accomplish said disengagement of said first and second bearing contact surfaces, an abutment surface positioned below said interconnecting means to support said interconnecting means when said discs are removed, and said interconnecting means being spaced above said abutment surface when the bearing surfaces on said arms engage the bearing surfaces on said discs.
2. Apparatus as claimed in claim I in which one of said first and second bearing surfaces is concave and the other is convex.
3. Apparatus as claimed in claim 1 in which said bearing surfaces are held in contact with each other by the weight of said arms and said interconnecting means.
4. Apparatus as claimed in claim 1 in which each said second bearing surface is concentric with the center of its respective substrate supporting disc.
5. Apparatus as claimed in claim 1 in which one of said first and second bearing surfacesis concave and the other is convex, said second bearing surface is concentric with the center of its respective substrate supporting disc, and the unit formed by said arms and said interconnecting means is supported by said discs and when so supported is out of contact with any portion of said apparatus other than said discs.
6. The apparatus as claimed in claim 1 in which said driving means comprises a motor, gear reduction means, and freewheel drive means between said gear reduction means and said driving track.
7. Apparatus as claimed in claim 5 in which said first bearing surface has a radius of curvature which is smaller than the radius of curvature of said second bearing surface.
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