US3777703A

US3777703A - Apparatus for supporting and rotating a workpiece

Info

Publication number: US3777703A
Application number: US00260025A
Authority: US
Inventors: R Gillie
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1972-06-02
Filing date: 1972-06-02
Publication date: 1973-12-11
Anticipated expiration: 1990-12-11

Abstract

A workpiece or substrate holder is rotatably supported on a revolving frame within a film deposition or coating chamber. A pair of pins are secured to the holder, symmetrically with respect to the axis of rotation of the holder, and are received within a channel formed on one side by an arcuate guide ring, having a sector thereof formed in an arcuate trackway, the radius of the trackway being less than the radius of the guide ring. Rotation of the frame advances the pins along the guide ring, and the trackway is so configured that only the leading pin enters it. As the leading pin progresses through the trackway, the lagging pin is swung out of the channel, around the leading pin in the trackway, and back into the channel as the leading pin, to rotate the workpiece holder to allow for the deposition of a film on both sides of the workpiece.

Description

[ 1 Dec. 11, 1973 Gillie [5 1 APPARATUS FOR SUPPORTING AND ROTATlNG A WORKPIECE [75] lnventor: Robert E. Gillie, Chicago, 111.

[73] Assignee: Western Electric Company,

incorporated, New York,'N.Y.

[22] Filed: June 2, 1972 [21] Appl. No.: 260,025

[52] U.S. Cl 118/49, 118/319, 198/33 R [51 I Int. Cl. C23c 13/08 [581 Field 01 Search 214/1 Q, 1 BC, 151,

214/707; 198/33 AB, 33 R; 118/319, 320, 423, 426, 49; 193/43 R, 43 C Primary ExaminerFrank E. Werner AttorneyW. M. Kain et a1.

[57] ABSTRACT A workpiece or substrate holder is rotatably supported ona revolving frame within a film deposition or coating chamber. A pair of pins are secured to the holder, symmetrically with respect to the axis of rotation of the holder, and are received within a channel formed on one side by an arcuate guide ring, having a sector thereof formed in an arcuate trackway, the radius of the trackway being less than the radius of the guide ring. Rotation of the frame advances the pins along the guide ring, and the trackway is so configured that only the leading pin enters it. As the leading pin progresses through the trackway, the lagging pin is swung out of the. channel, around the leading pin in the trackway, and back into the channel as the leading pin, to rotate the workpiece holder to allow for the deposition of a film on bothsides of the workpiece.

9 Claims, 6 Drawing Figures UNLOAD STATION PATENTEUBECH 1915 3.777703 sum 1 m 2 APPARATUS FOR SUPPORTING AND ROTATING A WORKPIECE BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates to a workpiece supporting and rotating apparatus, and in particular to an apparatus wherein a plurality of varying radii trackways rotate a holder for supporting a substrate within a vacuum chamber to successively position opposite surfaces of the substrate in registry with a film deposition device.

2. Description of the Prior Art Generally, present apparatus for supporting a substrate within a vacuum chamber, both sides of which substrate are to be metallized by a single vacuum deposition device, consists of one of two types. The first type is a relatively simple holder, rigidly mounted to a frame, which either immovably supports the substrate in registry with the deposition device or carries the substrate in a circular orbit past the deposition device. Use of this first type of apparatus requires, after one side of the substrate has been metallized, that atmosphere be introduced into the chamber to dissipate the vacuum therein so that the substrate may be manually rotated to present the opposite, unmetallized surface of the substrate to the deposition device, and then that the atmosphere in the chamber be again evacuated. This procedure is not only time consuming, and therefore costly, but also increases the possibility that contaminants may enter the chamber and reduce the quality and reliability of the metallized coating deposited on the substrate.

The second type of substrate supporting apparatus is a rotatable holder, which allows the substrate to be brought into registry with the deposition device, and rotated, so that both sides of the substrate may be metallized without dissipating the vacuum in the chamber. This type of holder, however,'is generally constructed with close tolerance gears, and chains or sprockets, all of which are troublesome in a vacuum deposition system due to the necessary lack of lubrication, high temperature, and buildup of evaporant material. Further- SUMMARY OF THE INVENTION In accordance with the present invention, an apparatus for advancing and rotating a workpiece includes a holder having a pivot axis,.for supporting the workpiece, a pivot arm mounted along the pivot axis of the holder and having a leading and a trailing end, and a drive mechanism for rotating the holder about a center. Also included is a'first facility for guiding the leading and trailing ends of the pivot arm to confine the advance of the holder to a circular are about the center, and a second facility, contiguous with the first facility, for guiding the leading end to pivot the arm and holder about the pivot axis and to move the trailing end into position in advance of the leading end as the holder continues to rotate about the center.

In a preferred embodiment of the invention for turning over the holder, or carrier, having the pivot axis, a pair of follower members are spaced along .a line passing through the pivot axis and on opposite sides of the pivot axis. The followers bear against a first arcuate guide rail having a first radius of curvature, and drive facilities are provided to advance the carrier with the followers bearing against the first guiderail to move the carrier in an arcuate path. As the followers advance along the first guide rail a second arucate guide rail, having a radius of curvature less than the first radius of curvature, is positioned to engage the leading follower member and to rotate the carrier about the pivot axis into a first aslant position.

A yieldable stop is positioned to engage the leading follower member to further rotate the carrier into a second aslant position, and to urge the follower against a straight guide rail section which is contiguous with the end of the second arcuate guide rail. Further advancing of the carrier moves the leading follower past the yieldable stop and into engagement with a third arcuate guide rail, contiguous with the end of the straight guide rail section, and having a radius of curvature less than the radius of curvature of the first guide rail. Engagement of the leading follower with the third guide rail further rotates the carrier into a position that completes the turnover of the carrier.

To bring the follower members back to bear against the first guide rail, instrumentalities are included for spanning the end of the third arcuate guide rail with the beginning of the first arcuate guide rail for bringing the lagging follower to bear against the first guide rail as the carrier is rotated into the position that completes its turnover, and for bringing the leading follower to bear against the first guide rail, behind the other follower member,.when it advances out of engagement withthe third guide rail, so that the leading follower becomes the lagging follower, and vice versa.

In the above preferred embodiment of the invention, the first, second, third and straight guide rails define a flat plane, and the-pivot axis of the carrier is perpendicular to the plane.

Other objects, advantages and features of the invention will be apparent upon consideration of the following detailed description when taken in conjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of the apparatus of the invention, showing the configuration of a guide and a trackway portion thereof for advancing and rotating a substrate carrying workholder relative to a vacuum deposition device;

FIG. 2 is a side elevation view of the substrate carrying apparatus;

FIG. 3 is a sectional view, taken along the line 3-3 of FIG. l,and illustrates the manner in which a substrate holder is supported and positioned within the guide;

FIG. 4 is a view, partially sectional, taken along the line 4-4 of FIG. 3, illustrating the manner in which the holder is rotatably supported;

FIG. 5 is a sectional view, taken along the line 5-5 of FIG. 1, and shows a portion of a substrate holder being received within the trackway portion of the guide, and

FIG. 6 is a sectional view, taken along the line 6-6 of FIG. 5, illustrating the manner in which the trackway portion of the guide rotates a substrate holder.

DETAILED DESCRIPTION The workpiece carrying apparatus of the present invention as shown in the drawings, for advancing and rotating a workpiece before a workstation to permit fabricating operations, such as coating, to be performed on opposite sides thereof, and more particularly for advancing and rotating a ceramic substrate before a vacuum deposition device within a vacuum chamber (not shown) for depositing a metal film on opposite sides thereof, includes a plurality of substrate holders l1, rotatably mounted along the periphery of a revolvable, reel shaped frame 12. The holders 11 bring successive ceramic substrates 13 into registry with a plurality of vacuum deposition devices 14 in response to rotation of the frame 12. The frame 12 is rotatably mounted within the opening of a U-shaped support 17, and has an arcuate, generally circular guide track 18, having a gap sector with a trackway positioned therein, associated therewith. The guide track 18 rotates the substrate holders 11, with respect to the frame 12, in response to rotation of the frame. This alternately posi tions opposite sides of the substrates 13 to receive a film deposition of metal.

More particularly, as best shown in FIGS. 1 through 3, the frame 12 is comprised of a circular top plate 21 and a circularbottom plate 22, the

top'and bottom plates

21 and 22 being parallel and joined at their centers by a hollow cylindrical sleeve 23 and along their peripheral sectionsby a series of equally spaced posts 26. The posts 26 impart rigidity to the frame 12 and stabilize the spacing between the peripheries of the

plates

21 and 22.

A shaft 27, extended through the sleeve 23 and centered therein by an upper bushing 28 and a lower bushing 31, is confined at each of its ends within the legs of the U-shaped support 17. The frame 12 is secured within the opening of the U-shaped support by the shaft 27 and is supported for rotation therethrough by a bearing 32 positioned between the bottom of the frame 12 and the lower leg of the support 17. A gear 33, attached to the bottom of the shaft 27 within the lower leg of a U-shaped support 17, is driven by any suitable means (not shown) to impart rotational movement'to the shaft 27. The rotational movement of the shaft 27 is transferred to the frame 12 through a locking device 36, which may be a simple nut and bolt or pin, extended through both the sleeve 23 and the shaft 27.

Rotatably positioned between each pair of adjacent posts 26 is a different substrate holder 1 l, the spacing between adjacent posts and the width of the holders being such as to allow unimpeded complete rotation of the holders within the frame 12. As shown in FIGS. 2 through 4, each holder 11 is rectangular in shape and is formed by two vertical members 37 and four horizontal members 38 which define three rectangular apertures in each holder 11. A different substrate 13 is positioned in registry with each aperture on each side of the holder 11 by any suitable mounting mechanism, such as a set of four L-shaped tabs 42. In this manner, each substrate holder 11 is capable of supporting six individual substrates 13.

Considering one of the substrate holders 1], the following description applies equally to all of the holders. The holder 11 is rotatably mounted on the frame 12 by an integral upstanding rod 43, at its top, which passes through the top plate 21 in an upper bearing 46, and by a rod 47 at its bottom, which passes through a lower bearing 48 and terminates in the bottom plate 22. The

rods

43 and 47 extend along the same axis, and with the

bearings

46 and 48 act as a pivot axis to rotatably secure the substrate holder 11 between the top plate 21 and the bottom plate 22 of the frame 12.

As shown in FIG. 4, a horizontal lever or pivot arm 51 is secured, parallel to the members 38, to the upper extremity of the top rod 43, and is provided at its ends with a pair of

upstanding stud shafts

52 and 53 having

follower rollers

54 and 55, respectively, mounted thereon. The

shafts

52 and 53 are symmetrically located with respect to the point at which the lever 51 is secured to the top rod 43, and therefore with respect to the axis of rotation of the holder 11. As is evident, rotation of the horizontal lever 51, in response to movement of the

follower rollers

54 and 55, rotates the substrate holder 11 with respect to the frame 12.

As shown in FIG. 3, a stationary, essentially circular cover 56 is positioned above the top plate 21 and is secured at its center to the end of the upper leg of the U- shaped support 17. The cover 56 has a side wall 57 which extends below the bottom plate 22 of the frame 12 and rests on the upper surface of the lower leg of the U-shaped support 17. Except for two openings, the purpose of which will be explained later, the cover 56 and its wall 57 enclose the top and the side of the frame 12.

Contiguous with the lower surface of the cover 56, and also secured at its center to the upper leg of the U- shaped support 17, is an essentially circular plate 58 having an outer peripheral surface 59 and a radius less than the radius of the cover 56. Also contiguous with the lower surface of the cover 56, and secured thereto, is an arcuate, essentially circular guide ring 60 having an inner peripheral surface 61. The guide ring 60 is concentric with the plate 58 and has an inner radius which is greater than the radius of the plate 58 and an outer radius which is less than the radius of the cover 56. The surfaces 59 and 61, and the portion of the lower surface of the cover 56 therebetween, together define the guide track 18.

The track 18 receives the

follower rollers

54 and 55 within a channel defined between the surfaces 59 and 61. Preferably, the follower rollers bear lightly against the surface 61 of the guide ring 60, so that as the frame 12 rotates and the followers advance within the channel and along the surface 61, the pivot axis of the holder 11, formed by the

rods

43 and 47, moves in an are determined by the arc of the surface 61, and the holder 11 moves in a path substantially tangent to the arc of the pivot axis. In this manner the angular position of the substrate holder 11, and therefore of the substrates 13, with respect to the frame 12, is determined by the position of the followers as defined by the surface 61.

As shown in FIGS. 1, 5 and 6, a generally arcuate trackway 64 spans at its ends a gap sector of approximately 60 in the guide track 18. The arcuate trackway 64 is comprised of three contiguous sections A, B and C, each section having in common an outer arcuate guide rail 66 which has a radius that is smaller than the radius of the guide track 18. The sections A and C have inner arcuate guide rails 68 and 70, respectively, which are parallel to the outer rail 66, and the section B has a straight inner guide rail 72 which is contiguous at each of its ends with a different one of the guide rails 68 or 70. The ends of the guide rail 66 do not enter the channel defined between the surfaces 59 and 60, while the ends of the guide rails 68 and 70 extend within the channel, so that the channel may be considered as being continuous from the area between the surfaces 59 and 61, through the area defined between the guide rail 66 and the guide rails 68, 70 and 72, and back into the area between the surfaces 59 and 61.

Referring to FIG. 6, with the frame 12 rotating in a clockwise direction to move the pivot axis of the holder 11 in an arcuate path, the

followers

54 and 55 advance along the surface 61 in a clockwise direction, and the guide rail 68 of the section A of the trackway 64 engages the leading follower (which, for the purpose of example, is the follower 54) and directs the follower into the channel defined between the guide rails 66 and 68. As the pivot axis continues along its arcuate path, the leading follower 54 advances into the section A, the lagging follower 55 is swung past the end of the guide rail 68, and the holder 11 is rotated in a counterclockwise direction about the pivot axis into a first position aslant of the tangent of the arc defined by the path of the pivot axis.

Continued rotation of the frame 12 advances the follower 54 through the section A, into the section B of the'trackway 64, and into engagement with a yieldable deflector member 74 positioned within the section B and in the path of the follower 54, which momentarily restrains the follower 54 to cause the holder 11 to further pivot about its axis in a counterclockwise direction into a second position aslant of the tangent of the are defined by the pivot axis. Continued rotation of the frame 12 forces the follower 54 into engagement with the straight guide rail 72, past the yieldable member 74, and into the section C of the trackway 64. t

The section C confines the follower 54 to a path which further moves it counterclockwise with respect to the pivot axis of the holder 11 and causes the follower 55 to swing past the end of the arcuate guide rail 70 and back into the channel of the guide track 18. Finally, the follower 54 advances out of, the section C and back into the channel of the track 18, with both the

followers

54 and 55 again advancing in a clockwise direction along the surface 61, and with the follower 55, which was originally the lagging follower, now being the leading follower, and with the follower 54, which was originally the leading follower, now being the lagging follower.

It is seen, therefore, that the trackway 64 receives the leading follower of the advancing holder 11, rotates the pivot arm 51 of the holder 11 toward and past the radius of the trackway 64, swings the lagging follower past the leading follower within the trackway 64, and reguides the followers back into the guide track 18 with the follower which was the lagging follower now being the leading follower, and vice versa. In this manner, em substrate holder iTis rotated through 180 vfith respect to the frame 12 with each complete rotation of the frame 12. A chamber 76, formed between the guide rails 68, 70 and 72 and the surface 59 of theplate 58, permits the lagging follower to swing past the leading follower in the trackway 64.

The side wall 57 of the cover 56 has two apertures (not shown) formed therein. A first aperture is formed at a position 80 where substrates are to be loaded and unloaded from a substrate holder 11. A second aperture is formed at a position 82, opposite the deposition devices 14, so that substrates 13 carried by the substrate holders 1 1 past the deposition devices 14 may receive a metal coating thereon. Two

shields

84 and 86, positioned on opposite sides of the deposition devices 14, prevent lateral travel of evaporant material provided from the devices 14.

In use, with the substrate carrying apparatus located within a vacuum chamber, the frame 12 is rotated through a first complete revolution to bring sequential substrate holders 11 into registry with the position at the load and unload station, so that three substrates may be loaded onto a first side of each substrate holder 11 in a parallel arrangement with the pivot axis of the holder formed by the

rods

43 and 47. The frame 12 is then rotated through a second complete revolution to bring a second and opposite side of successive substrate holders 1 1 into registry with the position 80 at the load and unload station so that three additional substrates may be loaded thereon. It is to be appreciated that with each complete revolutiqn gf the f r ame 12 each substrate holder is rotated through with respect to the frame 12, so that upon successive revolutions of the frame 12 alternate sides of the substrate holdersll are brought into registry with the load and unload station.

With substrates 13 loaded onto all of the substrate holders 1 1', the atmosphere within the chamber is evacuated and the frame 12 isrotated. Each rotation of the frame 12 carries the substrates on one side of the holders 11 past the deposition devices 14, the first complete rotation of the frame "12 presenting the substrates 13 on the first side of the substrate holders 11 to the evaporator guns 14, and the second complete rotation of the frame 12, after the substrate holders 11 have been rotated through 180, presenting the substrates 13 on the second side of the substrate holders 11 to the deposition devices 14. After the substrates on both sides of the holders 11 have beenc oated by the deposition devices 14, the vacuum within the chamber is disrupted and the coated substrates 13 are removed from the holders 11 at the load and unload station.

While one particular embodiment of the invention has been described in detail, it is understood that various other modifications and embodiments may be devised by one skilled in the art without departing from the spirit and scope of the invention-For example, if it is desired to coat both sides of a single substrate, the substrates 13 may be loaded on only one side of each substrate holderll and carried past the deposition devices 14. In this manner, the side of each substrate 13 facing away from the substrate holders 11 will be directly coated by the deposition devices 14 as they are brought into registry therewith, and the side of each substrate facing the substrate holders 11 will be coated by the deposition devices 14, through the apertures in the substrate holders 1 1, as they are brought into registry therewith. Further, it is not necessary that the apparatus of the invention be used in combination with a vacuum deposition chamber, but rather the apparatus may be used in any application where it is desired to alternately present opposite sides of a workpiece to a workstation.

What is claimed is:

1. In an apparatus for advancing and turning over a substantially planar workpiece:

a rotatable holder means, for supporting the workpiece in a plane parallelto its axis of rotation;

means for advancing the holder means with its axis of rotation in an arc to move the workpiece in a path substantially tangent to the arc of the axis;

means positioned in the path of the holder means for rotating the holder means about its axis to a first position aslant of the tangent of the arc;

a stop means, for momentarily arresting movement-of a portion of the holder means, to further rotate the holder means about its axis into a second position aslant of the tangent of the arc, and for then releasing the portion of the holder means upon continued advancement of the holder means, and

means for returning the released holder means into the original position with the workpiece turned over and advancing in a path substantially tangent to the arc of the advancing holder means axis of rotation.

2. An apparatus as recited in claim 1, wherein the means for advancing the holder means, with its axis of rotation in an arc, comprises:

a pivot arm, secured at its midsection to the axis of rotation of the holder means, and having a leading and a trailing end;

means for rotating the and y guide means, for guiding the leading and'trailing ends of the pivot arm, to guide the advancing holder means with its axis of rotation in an arc and with the workpiece moving in a path substantially tangent to the arc of the axis of rotation.

3. ln apparatus for turning an article over,

a frame, mounted for rotation, for holding the article;

a guide ring having a gap sector;

a pivot arm having its midsection secured to the frame;

a pair of guide rollers individually mounted on the ends of the arm;

means for advancing the frame with the guide rollers within the gap sector and bearing against the inner surface of the guide ring;

a trackway spanning'the gap sector for receiving the leading guide roller and for rotating the arm and holder, and

means for engaging the leading roller to further rotate the arm and frame to move the trailing roller into position to first engage the ring while the leading roller is moving from the trackway.

4. Apparatus as recited in claim 3, wherein the engaging means comprises:

a stop, positioned within the trackway, for momentarily resisting movement of the leading roller, to further rotate the arm and frame, and for then releasing the roller as it continues to move through the trackway.

5. In a turnover apparatus:

a carrier means having a pivot axis and a pair of follower members spaced along a line passing through the pivot axis and on opposite sides of the pivot axis;

a first arcuate guide rail having a first radius of curvature;

means for advancing the carrier means with both the follower members bearing against the guide rail to move the carrier means in an arcuate path;

a second arcuate guide rail, having a radius of curvature less than the first radius of curvature, for engaging the leading follower member as it advances holder means about a center,

along the first guide rail and for rotating the carrier means about the pivot axis into a first aslant position;

a straight guide rail section contiguous with the end of the second arcuate guide rail;

a yieldable stop, positioned for engaging the leading follower member, to further rotate the carrier means into a second aslant position and for urging the leading follower member against the straight guide rail, whereupon further advancing of the carrier means moves the leading follower member past the yieldable stop, and

a third arcuate guide rail, having a radius of curva ture less than the radius of curvature of the first guide rail and contiguous with the end of the straight guide rail section for engaging the leading follower member to further rotate the carrier means into a position that completes the turnover of the carrier means.

6. In a turnover apparatus as recited in claim 5, which further comprises:

means for spanning the end of the third arcuate guide rail with the beginning of the first arcuate guide rail for bringing the lagging follower member to bear against the first guide rail as the carrier means is rotated into the position that completes its turnover, and for bringing the leading follower member to bear against the first guide rail, behind the other follower member, when it advances out of engagement with the third guide rail, so that the leading follower member becomes the lagging follower member, and vice versa.

7. In a turnover apparatus as recited in claim 6,

wherein:

the first, second, third and straight guide rails define a flat plane, and

the pivot axis of the carrier means if perpendicular to the plane.

8. In an apparatus for supporting and guiding a substrate along an endless loop track within a vacuum chamber to successively position opposite surfaces of the substrate in registry with a film deposition device:

a rotatable substrate holder, for supporting the substrate in a plane parallel to its axis of rotation;

means for advancing the holder along the track, the holder at a point along the track positioning a first surface of the substrate in registry with the film deposition device;

means positioned in the path of the holder for rotating the holder about its axis to a first aslant position with respect to the track;

a stop means for momentarily arresting movement of a portion of the holder, to further rotate the holder to a second aslant position with respect to the track, and for then releasing the portion of the holder upon continued advancement of the holder, and

means for returning the released holder to a position,

with respect to the track, that is opposite to the position of the holder prior to rotation thereof, to position a second and opposite side of the substrate in registry with the film deposition device as the holder is again advanced to the point along the track.

9. Man apparatus for advancing and rotating a workpiece:

a frame mounted for rotation about a first axis;

face;

a guideway running offset from the inner surface for engaging the leading follower to pivot the holder about the second axis to position the trailing follower in front of the leading follower as the followers leave the guideway and again engage the inner surface.

L- 566- PT v UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patemNo. 3,777,703 Dated ec e 11. 1973 Inventor( Robert E. Gillie It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, lines 52-63, starting with"holder"and ending with 1 "center", should be deleted, and the following should be inserted in its place: -rotatable holder for supporting the workpiece in a plane parallel to its, axis of rotation, a drive mechanism for advancing the holder with its axis of rotation in an arc to move the workpiece in a path substantially tangent to the arc of the Y axis, and a guide, positioned in the path of the holder, for rotating the holder about, its axis to a first position aslant of the tangent of the arc, Also included is a stop mechanism, for momentarily arresting movement of a portion of the holder to further rotate the holder about its axis into a second position aslant of the tangent of the arc, and for then releasing I the portion of the holder upon continued advancement of the holder, and a facility for returning the released holder into the original position with the workpiece turned over and advancing in a path substantially tangent to the arc of the advancing holder's axis of rotation,

I Column 4, line 58, "60'" should read --60. Column 8, line 37,

"if" should read --is-.

' Signed-and. sealed this 7th day of May 19m.v I

SEAL Atte st:

EDWARD l-I.FLETGIIER,J R. c. MARSHALL ,DANN Attesting Officer i Commissioner of Patents

Claims

1. In an apparatus for advancing and turning over a substantially planar workpiece: a rotatable holder means, for supporting the workpiece in a plane parallel to its axis of rotation; means for advancing the holder means with its axis of rotation in an arc to move the workpiece in a path substantially tangent to the arc of the axis; means positioned in the path of the holder means for rotating the holder means about its axis to a first position aslant of the tangent of the arc; a stop means, for momentarily arresting movement of a portion of the holder means, to further rotate the holder means about its axis into a second position aslant of the tangent of the arc, and for then releasing the portion of the holder means upon continued advancement of the holder means, and means for returning the released holder means into the original position with the workpiece turned over and advancing in a path substantially tangent to the arc of the advancing holder means axis of rotation.

2. An apparatus as recited in claim 1, wherein the means for advancing the holder means, with its axis of rotation in an arc, comprises: a pivot arm, secured at its midsection to the axis of rotation of the holder means, and having a leading and a trailing end; means for rotating the holder means about a center, and guide means, for guiding the leading and trailing ends of the pivot arm, to guide the advancing holder means with its axis of rotation in an arc and with the workpiece moving in a path substantially tangent to the arc of the axis of rotation.

3. In apparatus for turning an article over, a frame, mounted for rotation, for holding the article; a guide ring having a gap sector; a pivot arm having its midsection secured to the frame; a pair of guide rollers individually mounted on the ends of the arm; means for advancing the frame with the guide rollers within the gap sector and bearing against the inner surface of the guide ring; a trackway spanning the gap sector for receiving the leading guide roller and for rotating the arm and holder, and means for engaging the leading roller to further rotate the arm and frame to move the trailing roller into position to first engage the ring while the leading roller is movinG from the trackway.

4. Apparatus as recited in claim 3, wherein the engaging means comprises: a stop, positioned within the trackway, for momentarily resisting movement of the leading roller, to further rotate the arm and frame, and for then releasing the roller as it continues to move through the trackway.

5. In a turnover apparatus: a carrier means having a pivot axis and a pair of follower members spaced along a line passing through the pivot axis and on opposite sides of the pivot axis; a first arcuate guide rail having a first radius of curvature; means for advancing the carrier means with both the follower members bearing against the guide rail to move the carrier means in an arcuate path; a second arcuate guide rail, having a radius of curvature less than the first radius of curvature, for engaging the leading follower member as it advances along the first guide rail and for rotating the carrier means about the pivot axis into a first aslant position; a straight guide rail section contiguous with the end of the second arcuate guide rail; a yieldable stop, positioned for engaging the leading follower member, to further rotate the carrier means into a second aslant position and for urging the leading follower member against the straight guide rail, whereupon further advancing of the carrier means moves the leading follower member past the yieldable stop, and a third arcuate guide rail, having a radius of curvature less than the radius of curvature of the first guide rail and contiguous with the end of the straight guide rail section for engaging the leading follower member to further rotate the carrier means into a position that completes the turnover of the carrier means.

6. In a turnover apparatus as recited in claim 5, which further comprises: means for spanning the end of the third arcuate guide rail with the beginning of the first arcuate guide rail for bringing the lagging follower member to bear against the first guide rail as the carrier means is rotated into the position that completes its turnover, and for bringing the leading follower member to bear against the first guide rail, behind the other follower member, when it advances out of engagement with the third guide rail, so that the leading follower member becomes the lagging follower member, and vice versa.

7. In a turnover apparatus as recited in claim 6, wherein: the first, second, third and straight guide rails define a flat plane, and the pivot axis of the carrier means if perpendicular to the plane.

8. In an apparatus for supporting and guiding a substrate along an endless loop track within a vacuum chamber to successively position opposite surfaces of the substrate in registry with a film deposition device: a rotatable substrate holder, for supporting the substrate in a plane parallel to its axis of rotation; means for advancing the holder along the track, the holder at a point along the track positioning a first surface of the substrate in registry with the film deposition device; means positioned in the path of the holder for rotating the holder about its axis to a first aslant position with respect to the track; a stop means for momentarily arresting movement of a portion of the holder, to further rotate the holder to a second aslant position with respect to the track, and for then releasing the portion of the holder upon continued advancement of the holder, and means for returning the released holder to a position, with respect to the track, that is opposite to the position of the holder prior to rotation thereof, to position a second and opposite side of the substrate in registry with the film deposition device as the holder is again advanced to the point along the track.

9. In an apparatus for advancing and rotating a workpiece: a frame mounted for rotation about a first axis; means for rotating the frame about the first axis; a workpiece holder pivotally mounted about a secoNd axis on the frame; a guide ring having an inner surface centered about the first axis; a leading follower and a trailing follower secured to the workpiece holder and spaced on opposite sides of the second axis for bearing against the inner surface; a guideway running offset from the inner surface for engaging the leading follower to pivot the holder about the second axis to position the trailing follower in front of the leading follower as the followers leave the guideway and again engage the inner surface.