US2957400A - Photographic printing apparatus - Google Patents

Description

Oct. 25, 1960 M. H. SUSSIN FHOTOGRAPHIC PRINTING APPARATUS 4 Sheets-Sheet 1 Filed June 6, 1958 R N ms mw 5 VS mm W. N H R O F X A A M VACUUM MOTOR PUMP Oct. 25, 1960 M. H. SUSSIN PHOTOGRAPHIC PRINTING APPARATUS 4 Sheets-Sheet 2 Filed June 6, 1958 INVENTOR. MAX H. SUSSIN A TORNEYS Oct. 25, 1960 M. H. sussm 2,957,400

PHOTOGRAPHIC PRINTING APPARATUS Filed June 6, 1958 4 Sheets-Sheet 3 INVENTOR.

MAX H. SUS SIN K I 't TORNEYS Oct. 25, 1960 M. H. susslN 2,957,400

PHOTOGRAPHIC PRINTING APPARATUS Filed June 6, 1958 4 Sheets-Sheet 4 34 n A I INVENTOR. MAX H. SUSSIN w @M, wm zfw k ATTO RN EYS United States Patent PHOTGGRAPHIC PRINTING APPARATUS Max H. Sussin, Chicago, 111., assignor to Robertson Photo- Mechanix, Inc., Chicago, Ill., a corporation of Illinois Filed June 6, 1958, Ser. No. 740,223

12 Claims. (Cl. 95---76) The present invention relates broadly to the printing of photographically produced images, and is more particularly concerned with a new and improved apparatus for rapidly and effectively printing photographic negatives.

Printing frames of the character wherein the work is located between a vacuum blanket and glass frame and exposed to are lights have been proposed and utilized in Various forms in the past. Each of the devices of which applicant is aware, however, possesses objections and disadvantages by reason of being cumbersome, unnecessarily complicated, and not completely reliable. In many constructions an unduly large number of latches and locks have been employed in an endeavor to assuresuccessful operation of the apparatus, and the result has beena mechanical assemblage requiring utmost dexterity and patience on the part of the operator.

It is therefore an important aim of the present invention to provide a novel printing apparatus comprised of a minimum number of readily fabricated and easily assembled parts.

Another object of the invention lies in the provision of a photographic printing mechanism operable with ease by a single person and requiring a minimum number of steps and assuring uniform and excellent results therefrom.

Another object of this invention is to provide a new and improved printing frame construction which is read ily'transportable, and is comprised of parts constructed and arranged to permit pivotal movement of glass and blanket frames to a printing position with ease and speed and requiring only minimum space for accomplishment of this function.

A further object of the present invention lies in the provision of printing apparatus incorporating glass and vacuum blanket frames characterized in part by a counterbalanced glass frame to facilitate the loading and unloading operation, and wherein the pressure of the glass frame on the blanket frame may be readily adjusted to accommodate a wide variety of work thicknesses without danger of breakage or damage thereto, as Well as to reduce blanket wear and compensate for blanket beading tolerances.

A still further object of this invention is to provide a photographic printing device in which a single hand movement by the operator essentially simultaneously locks the glass frame to the blanket frame and draws vacuum therebetween with the advantageous elimination of the large number of latch means and safety locks characterizing the prior art structures.

An even further object of this invention is to provide in apparatus of the foregoing character novel means which insures that tipping or rotation of the glass and blanket frames can be accomplished only when one is locked to the other.

Other objects and advantages of the invention will become more apparent during the course of the following description, particularly when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

Figure 1 is acabinet style printing apparatus embodying the features of the present invention;

Figure 2 is a diagrammatic illustration, partly in section, of the vacuum system and associated locking mechanism for the vacuum blanket frame;

Figure 3 is an end view of apparatus constructed in accordance with the principles of this invention, with parts broken away to show mechanism for tilting the glass frame and locking the same to the blanket frame;

Figure 4 is a detail end view illustrating the operation of the lever mechanism in locking the glass frame with respect to the'blanket frame;

Figure 5 is a fragmentary sectional view of one form of vacuum blanket;

Figure 6 is an end view of a portion of the apparatus to show the positioning of parts during tiltable movement of the glass frame;

Figure 7 is a vertical sectional view taken substantially along the line VIIVII of Fig. 3; and

Figure 8 is a sectional view of another form of air locking mechanism.

Briefly stated, a printing apparatus as constructed in accordance with the principles of this invention comprises a supporting structure pivotally mounting a vacuum blanket frame to which is hingedly connected a glass frame floatable thereon. Associated with the glass frame is a linkage pivoted to the supporting structure and actionable under the influence of a counter-balance force to permit raising the glass frame with respect to the blanket frame when loading or unloading work therebetween. A control lever connecting with lever arms is effective to simultaneously lock the glass frame to the blanket frame and initiate the drawing of vacuum from between the frames and an unlocking of the blanket frame from the supporting structure. The assembly may then be pivoted about the connection to the structure to expose the work to are lights or the like. Other structural and operational features will become apparent during the course of the description now to follow.

Referring now to the drawings, and first to Figures 1, 3 and6 thereof, the printing apparatus of this invention is designated generally by the legend A and is preferably constructed to include a plurality of uprights 10 between which extend end walls 11 and front and rear side walls 12 and 13, respectively. A four panel construction may of course be employed, and in this instance the uprights 10 would be eliminated. Interiorly of the supporting framework provided by the walls and uprights are a plurality of bracing .members 14 positioned as desired to rigidify the apparatus. Longitudinally extending bracing members (not shown) may also be provided, and upon one or more of the latter members adjacent the front wall 12 the vacuum pump and motor arepreferably positioned. Substantially the entire rear half of the apparatus is free of interfering structure in order to permit tiltable movement of the glass and blanket frames now to be described.

By locating the vacuum pump and other means upon bracing members, a bottom wall is not normally required in the apparatus disclosed. Providing a top wall for the apparatus A when in the closed position of Figures l and 3 is a frame assembly indicated generally at 15 and comprising a frame 16 supporting a piece of clear glass 17 and a frame 18 to which a vacuum blanket 19 is attached along one surface thereof. As used in the specification and claims, the word glass is intended to include all transparent sheet materials as certain plastics are suitable.

As shown in Figure 5, the blanket 19 preferably comportion 21 of general Y-shape in cross-section.

blanket frame 18 adjacent the rear wall thereof.

The blanket 19 may be fabricated of corrugated rubber and cloth or other suitable materials, and is attached to the frame 18 by screws, adhesive means or in any other desired manner. When the assembly A is closed as in Figures 1 and 3, the glass frame 16 or work is received upon the blanket frame 18 in sealable relation therewith and the Y-shaped portion of the vacuum blanket 19 compressed to effect an air-tight seal. Other seal constructions may of course be employed.

It is of importance when the glass frame 16 is lowered from the position of Figure 6 to that of Figure 3, following the positioning of work between the glass frame and blanket frame, that substantially all portions of the periphery of the glass frame exert uniform pressure upon the blanket frame and work located thereon in order to assure a proper seal and to avoid damage to the work which may in many instances include a glass plate. For the accomplishment of these purposes, a floatable connection is provided between the glass frame 16 and blanket frame 18. A form which such a connection may take is shown in Figures 3 and 6, and comprises a bracket member 22 fixed to the marginalend portions of the The bracket member 22 may be generally triangularly shaped and provided at one end thereof is a slot 23 receiving a pin 24 spaced inwardly of the rear wall of the glass frame and carried by the opposite end walls thereof. The glass frame 16 is accordingly pivotally connected to the blanket frame 18 by the pin 24 received in the bracket member slot 23, and since this phantom hinge arrangement permits limited vertical movement of the glass frame with respect to the blanket frame during lowering of the former unto the latter, constant and uniform pressure is exertedby the glass frame throughout its peripheral contact with the blanket frame.

To expose work or photographic media positioned within the frame assembly 15 to are lights or the like located generally rearwardly of the apparatus A, the blanket and glass frames comprising said frame assembly is tilted or rotated to an angle of approximately 90 degrees. To accomplish this movement, which is re quired to prevent deleterious substances from the arc lights contacting the glass 17, the blanket frame 1 8 carries at opposite ends generally midway of the width of the frame a pivot pin or the like 25. To accomplish a better balance, however, the pin 25 may be located slightly off the longitudinal center line of the blanket frame, and in any event, are receivable within a slot 26 (Figure 4) provided in a bracket 27 secured by screws or the like 28 to the inner surface of each of the side panels 11 of the assembly A. The bracket 27 may be of generally right angular shape in order to provide clearances for mechanisms later to be described.

To raise or lower the glass frame 16 independently of the blanket frame 18, as when loading or unloading work from the frame assembly 15, there is provided a pivot bracket 29 of the character shown in Figure 7. The bracket 29 may be cast or otherwise formed to include a pair of spaced pins 30 along one surface receivable in slots 31 provided at opposite ends of the glass frame 16. Provided along the same surface of the bracket 29 and spaced downwardly from the pins '30 is a slot 32 provided to receive one end of the pivot pin 25 carried by the blanket frame 18. The slot 32 is located generally midway of the width of the bracket 29 and serves to limit the pressure exerted by the glass frame 16 upon the blanket frame 18 when the frames are locked with respect to one another in the manner later to be described. That is, the depth of the slot controls the extent of downward travel of the glass frame.

Connecting with pivot bracket 29 by pin means or the like 33 is a push bar or lever bar member 34. The pin 33 is fixed to the bracket 29 at 35 and provides a pivot point for the lever bar 34 during raising or lowering f the glass frame 16. The pin passes through a slot 36 in the lever bar 34 and bears against an adjustment plate 37 having an opening "38 therein receiving the pin 33. The adjustment plate 37 connects with the lever bar 34 by means of bolts 39 or the like passed through a slot 40 in the plate 37 and threaded into an opening 41 in the lever bar 34. By the arrangement described, adjustment may be made to accommodate work of various thicknesses between the glass frame 16 and blanket frame 18 without the danger of damage thereto when the glass frame is brought down upon the blanket frame. Further, and possibly of even greater importance, wear on the vacuum blanket is markedly reduced and there may be accommodated variations in the cross-sectional thickness of the blanket peripheral portion 21.

The lever bar 34 is connected at one end to the glass frame 16 in the manner above disclosed, and at its opposite end connects with a balance arm 42 by pin means or the like 43. The opposite end of the balance arm 42 is pivotally connected at 44 to the framework, either by attachment to the uprights 10, end panels 11 or a brace 14. The balance arm is provided along its length with a plurality of openings 45 to control the extent of tension in a counter-balance spring 46 secured at its opposite end to either an upright 10 or side panel 11. By use of the counter-balance spring 46 and arms 34 and 42, swingable movement of the glass frame 16 is facilitated and the glass frame 16 held in a semi-open position when the apparatus is not in use, and thereby wear on the vacuum blanket 19 is reduced.

To draw the glass frame 16 into firm contact with the blanket frame 18, and lock said glass frame to said blanket frame, the lever bar member 34 has attached thereto a pin or stud 47 as best shown in Figure 7. To accomplish these functions the pin 47 is engaged by book means 48 (Figure 4) rigidly connected at 49 to a pivot plate 50 swingably mounted at 51 upon a plate member 52 attached to each of the side panels 11 by screws or the like 53. Spring means 54 is connected at one end to the hook member 48 and at the opposite end to each side panel 11, and functions to hold the hook member in a non-interfering position when the glass frame 16 is raised or lowered independently of the blanket frame 18. A roller device 55 of the adjustable type is provided to guide the hook member 48 into engagement with the pin or stud 47 on the lever bar 34.

The pivot plate 50 carries a pin connection 56 providing a pivot joint with a lever arm 57 swingably associated at 58 with a connecting arm 55 pinned upon a shaft 60 carried by each of the plates 52 or by the end walls 11 and extending essentially entirely along the length of the apparatus A. A control handle 61 is also supported by the shaft 60 and travels in an arc clockwise and counterclockwise to cause rotation of the shaft and either locking or release of the glass frame and the other functions to be described.

A mercury switch 62 is mounted upon the shaft 60 for rotation therewith and connections 63 from the switch lead to a motor M shown diagrammatically in Figure 2. A vacuum pump P is operated by said motor and draws vacuum through a line 64 terminating as shown in the vacuum blanket 19. A bleeder connection 65 is provided controlled by a knob 66 extending outwardly of the front panel 12 of the apparatus A and located in a recess 67 therein. A vacuum indicator 68 is also positioned in the front wall recess, and by adjustment of the knob 66 on the bleeder connection, vacuum pressure may be regulated and the desired degree of vacuum drawn through the line 64.

Connecting also with the vacuum blanket 19 is a line 69 terminating in an air lock device 70. The device 70 may be of any desired construction, and a preferred structural arrangement comprises a cylinder 71 having a base plate 72 at one end and a top plate 73 at the opposite end receiving the vacuum line 69. Movable within the cylinder'71 is a piston 74 supported upon a shaft 75 and backed by a cup 76 and washer 77. A spring 78 bears at one end against the washer 77 and at its opposite end against a wall of the top plate 73. A gasket 79 may be provided to eifect proper sealing of the parts.

The shaft 75 is shaped to include a relatively slender portion 80 and a relatively thicker portion 81, and at one end of the relatively lesser diameter portion 80 of the shaft 75 is a knob 82. A plate 83 depends downwardly from the blanket frame 18 and said plate is provided with a keyhole slot 84 opening with its larger portion along the lower edge of the plate 83. As is now apparent, the spring 78 causes the relatively larger diameter portion 81 of the shaft 75 to bear against the smaller portion of the keyhole slot to lock the blanket frame to the supporting structure. By pressing inwardly on the knob .82, or drawing vacuum through the line 69 from the air lock device 75], the shaft 75 will move inwardly to permit the relatively smaller and relatively larger portions of the keyhole slot 84 to be passed upwardly from the reduced port-ion 80 of the shaft 75 to release the blanket frame 18 from supporting structure. The design of the air lock 70 and the vacuum pressure are of course, controlled to assure that the blanket frame will not be released from supporting structure until sufiicient vacuum has been drawn to properly hold the work against the vacuum blanket 19 when the frame assembly 15 is tipped into a vertical position. Further, as will be described hereinafter, when the vacuum is released the force of the spring 78 in the air lock will again secure the larger diameter portion 8 1 of the shaft '75 against the smaller portion of the keyhole slot 85 and thereby lock the blanket frame to the supporting structure.

To facilitate tiltable movement of the glass frame 16 about the pivotal connection 23 and 24 with the blanket frame 18, as when inserting or removing Work from between the two frames, a handle or equivalent means 85 is provided along the front wall of the glass frame 16. Further, to accommodate the lever bar member or push bar 34 during the noted tilting movement, the printing apparatus A is provided with openings 86 at opposite ends thereof.

The operation of applicants new and improved printing apparatus may be described as follows. The blanket frame 18 is normally secured by the described air lock device 7! and plate 83 to supporting structure, and when in this secured position the operating lever 61 is moved clockwise or rearwardly to disengage the hook member 48 from the pin or stud 47 on the push bar 34 and thereby effect a release of the glass frame 16 from the blanket frame 18. The glass frame is thereupon raised, preferably by grasping the handle 85, and during this movement the balance bar 42 proceeds upwardly about the pivot point "44 to swing the push bar 34 diagonally rearwardly about the pivot connection 43, raising the glass frame about its pivotal connection 23 and 24 with the blanket frame 18. During said upward and diagonally rearward movement of the push bar, the upper end thereof pivots to a minor degree about the pin connection 33.

The work to be printed, which may be in the form of a plate and negative, is then positioned upon the vacuum blanket 19 of the blanket frame 18 and the glass frame 16 lowered into position. The slot 32 of the pivot bracket 29 connected to the glass frame is at this time received upon or about the pivot pin 25 carried at opposite ends of the glass frame 18, said pin 25 being permanently received within the slots 26 in each of the brackets 27. The operating handle 61 is then rotated counterclockwise or rearwardly, and during this motion of the handle, the locking mechanism proceeds through the position indicated in Figure 4 by the direction of arrows and by the dotted lines thereon. Counter-clockwise movement of the control lever 61 causes corresponding rotation of the shaft 60 and connecting lever '59 thereon. The lever 59 proceeds rearwardly and downwardly through a limited arc, and by virtue of the pivot connection 58 to a lever arm 57, the latter arm is similarly moved rearwardly and downwardly in the manner indicated in Figure 4. The connection 56 between the pivot plate 56 and lever arm 57 induces an upward or clockwise travel of the pivot plate 50 about the rigid pivot 51 fixed to the plate 52. As the plate 50 rotates upwardly the hook member 48 is drawn downwardly and rearwardly in rolling contact with the guide roller 55 to engage the hook member with the stud or pin on the push rod 34 and draw said rod downwardly to lock the glass frame 16 against the blanket frame 18 in the positions illustrated in Figures 3 and 7. It is to be particularly noted that during the final phase of push rod movement, said rod travels in a true vertical direction and thereby there is no shifting of the glass frame relative to the blanket frame.

Essentially simultaneously with the locking action described, rotation of the shaft 60 causes tipping of the mercury switch 62 to start the motor M and begin operation of the vacuum pump P. Vacuum is thereupon drawn from the blanket 19 through the line 64 and through the line 69 to release the shaft 75 of the air lock 70 from the plate 83 on the blanket frame 18. The frame assembly 15 comprising the glass frame 16 and blanket frame 18 with the work positioned therebetween may then be rotated or swung on the blanket frame pivot pins 25 carried in the slots 26 of the brackets 27. The hook 48 during the tilting of the frame assembly 15 of course remains in engagement with the stud 47 on the push arm or lever 34. The frame assembly 15 is rotated or pivoted approximately degrees in a clockwise direction to locate the frame assembly generally vertically or in an upright position in order to permit exposure of the work to arc lights or the like positioned generally rearwardly of the printing apparatus A.

After exposure of the work therein, the frame assembly 15 is restored to a horizontal position and the operating lever 61 moved clockwise or rearwardly to turn off the vacuum pump and motor. This causes the lanket frame 18 to be locked to the supporting structure by action of the air lock 70, and rotation of the shaft 60 releases the hook 48 from the stud or pin 47 on the push rod 34. With the glass frame 16 thus unlocked from the blanket frame 18, said glass frame may be pivoted upwardly as shown in Figure 6 to permit removal of the exposed work. Disengagement of the hook 48 from the stud or pin 47 occurs by reason of the movement of the parts shown in .dot-and-dash lines in Figure 4.

If desired, an air locking mechanism of the character shown in Figure 8 may be employed in substitution for the device 7 of Figure 2. Designated generally by the numeral 87, the construction of Figure 8 is of the diaphragm type and includes a top plate 88 having a radial bore 89 communicating at one end with a hose connection 90 and at the opposite end with an axial bore 91 bottoming a spring 92. The spring connects with one end of a shaft 93 supporting a collar 94 receiving a. diaphragm 95 secured at its periphery by a housing or cylinder 96- which may be of a two part construction. The shaft travels axially in a bushing 97 carried in a base plate 98 aper-tured at 99. The knob 82a and shaft portions 89a and 81a are essentially the same as in the form of Figure 2, to permit locking and unlocking with the plate 83a as earlier described. It will now be apparent that by drawing vacuum through the bores 89 and 91 and through the connection 90, diaphragm movement in generally its central portion to the right or rearwardly will occur to cause axial travel of the shaft 93 and release of said shaft from the keyhole slot 84a of the plate 83a on the blanket frame 18.

It may be seen from the foregoing that applicant has provided a novel printing apparatus characterized by relative simplicity of operation permitted by a new and improved arrangement of a number of readily fabricated and assembled parts. The mechanism locking the glass frame to the blanket frame is rapid acting, and being constructed of lever linkages, assures that malfunctions will be essentially entirely absent therefrom.

arrangement locking the blanket frame to the supporting structure, it is essentially impossible .to tip the blanket .frame when the glass frame is not secured thereto. The apparatus may be readily operated by a single person and consistently uniform results obtained from its operation.

It is to be understood that the form of the invention therein shown and described is to be taken as the preferred embodiment of the same, and that various changes in the size, shape and arrangement of parts may be effected without departing from the spirit of .the invention or the scope of the subjoined claims.

I claim as my invention: 1. Apparatus for printing photographic media, comprising a supporting framework, a vacuum blanket frame pivotally supported on said framework, a glass frame supported for tiltable movement with respect to the blanket frame to permit loading and unloading of the media therebetween, means for securing the glass frame to the blanket frame to prevent separation of said frames during pivotal movement thereof, means connecting the blanket frame to a source of vacuum, means locking the blanket frame to the supporting framework when the glass frame is unsecured to the blanket frame, and means vconnecting the blanket frame to the locking means and providing release of the blanket frame from the supporting framework when the vacuum pressure has reached a predetermined point.

2. Apparatus for printing photographic media, comprising a supporting framework, a vacuum blanket frame pivotally supported on said framework, a glass frame pivotally connected at opposite ends to the blanket frame and adjustably swingable relative thereto to permit loading and unloading of the media between said frames, means for securing the glass frame to the blanket frame to prevent separation of said frames during pivotal movement thereof, said means comprising a linkage actuated member drawing the glass frame into continuous contact 'with the blanket frame and maintaining the same thereon, means connecting the blanket frame to a source of vacuum, means locking the blanket frame to the supporting framework when the glass frame is unsecured to the blanket frame, and means connecting the blanket frame to the locking means and providing release of the blanket frame from the supporting framework when the vacuum pressure has reached a predetermined point.

3. Apparatus for printing photographic media, comprising a supporting framework, a vacuum blanket frame pivotally supported on said framework, a glass frame supported for tiltable movement with respect to the blanket frame to permit loading and unloading of the media therebetween, means for securing the glass frame to the blanket frame to prevent separation of said frames during pivotal movement thereof, means connecting the blanket frame to a source of vacuum, means locking the blanket frame to the supporting framework when the glass frame is unsecured to the blanket frame, said means comprising an air lock device provided with a movable shaft and a plate member having a keyhole slot therein receiving said shaft and lockable therewith, and means connecting the blanket frame to the air lock device and providing release of the shaft thereof from the plate member when the vacuum pressure has reached a predetermined point.

4. Apparatus for printing photographic media, comprising a supporting framework, a vacuum blanket frame pivotally supported on said framework, a glass frame supported for tiltable movement with respect to the blanket frame to permit loading and unloading of the media therebetween, means for securing the glass frame to the blanket frame to prevent separation of said frames during pivotal movement thereof, said means including a lever member pivotally associated with the supporting framework and carrying a pin thereon, and a swingable hook member engageable with the pin and drawing the glass frame into continuous contact with the blanket frame and maintaining the same thereon, means connecting the blanket frame to a source of vacuum, means locking the blanket frame to the supporting framework when the glass frame is unsecured to the blanket frame, and means connecting the blanket frame to the locking means and providing release of the blanket frame from the supporting framework when the vacuum pressure has reached a predetermined point.

5. Apparatus for printing photographic media, comprising a supporting framework, a vacuum blanket frame pivotally supported on said framework, a glass frame supported for tiltable movement with respect to the blanket frame to permit loading and unloading of the media therebetween, a lever member connected at one end to the glass frame and pivotally associated with the supporting framework at its opposite end and swingable vertically and diagonally to tilt the glass frame about its support with the blanket frame, a hook member associated with the framework and cooperating with the lever member to draw said member and glass frame downwardly and lock the glass frame in continuous peripheral contact with the blanket frame, means connecting the blanket frame to a source of vacuum, air actuated locking means engageable with the blanket frame and securing the same to the supporting framework when the hook member is disassociated from the lever member, and means to load and unload the media therebetween, a lever member connected at one end to the glass frame and carrying a pin thereon, a rotatable shaft supported by the framework, a linkage connected to the shaft and carrying a pin engaging member efiective upon rotation of the shaft to contact the lever pin and draw the glass frame into locked engagement with the blanket frame to prevent separation of said frames during pivotal movement thereof, means connecting the blanket frame to a source of vacuum, and means locking the blanket frame to the supporting framework when the glass frame is unsecured to the blanket frame, said locking means being operable upon shaft rotation in one direction to lock the blanket frame to the framework and upon shaft rotation in another direction to release said frame from said framework to permit pivotal movement thereof into a printing position.

7. Apparatus for printing photographic media, comprising a supporting framework, a vacuum blanket frame pivotally supported adjacent its centerline on said framework for rotation therein to an essentially vertical position during printing of the media, a glass frame supported for tiltable movement with respect to the blanket frame to load and unload the media therebetween, a lever memher connected at one end to the glass frame and carrying a pin thereon, a rotatable shaft supported by the framework, a linkage connected to the shaft and carrying a pin engaging member effective upon rotation of the shaft to contact the lever pin and draw the glass frame into locked engagement with the blanket frame to prevent separation of said frames during pivotal movement thereof, means connecting the blanket frame to a source of vacuum, and means locking the blanket frame to the supporting framework when the glass frame is unsecured to the blanket frame, said locking means comprising an air operated cylinder and a piston therein supporting a shaft, and a plate member having a slot therein receiving the shaft of said piston, the shaft supported by the framework being operable when rotated in one direction to actuate the linkage and lock the glass frame to the blanket frame and after a predetermined period release the piston shaft from the plate member slot to permit pivotal movement of the blanket frame into a printing position.

8. In combination with a vacuum blanket supporting frame and glass supporting frame pivotally mounted upon a framework, the improvement which comprises a source of vacuum, means connecting the vacuum source to the vacuum blanket, locking means on the framework connecting with the blanket, and plate means on the blanket supporting frame having a slot therein, said locking means comprising a cylinder, a piston movable therein and carrying a shaft, and a spring in said cylinder normally urging the shaft into locking engagement with the slot in the plate means, said locking and plate means securing the blanket frame to the framework until a predetermined vacuum pressure has been drawn between the blanket and glass frames and thereupon releasing the blanket frame to permit pivotal movement thereof.

9. Apparatus for printing photographic plates and the like, comprising a cabinet structure including side and end walls, a frame assembly adapted to close the top of said cabinet and comprised of a blanket frame pivotal- 1y carried at opposite ends by the cabinet end walls and a glass frame floatably mounted upon the blanket frame and pivotable relative thereto, a bar member connected at one end to the glass frame to raise and lower the same independently of the blanket frame, a lever arm pivotal- 1y joined to the cabinet and connecting at its opposite end to the bar member to swing said member vertically and diagonally during pivotal movement of the glass frame, a locking mechanism connecting the glass frame to the blanket frame to prevent separation of said frames during tilting thereof, vacuum means connecting with the blanket frame, an air locking mechanism securing the blanket frame to the cabinet and connecting with the vacuum means to release the frame from the cabinet when vacuum pressure has reached a predetermined point, and a lever mechanism connecting with the first locking mechanism and effective upon movement to lock the glass frame to the blanket frame and cause operation of the vacuum means and release of the blanket frame from the cabinet.

10. Apparatus for printing photographic plates and the like, comprising a cabinet structure including side and end walls, a frame assembly adapted to close the top of said cabinet and comprised of a blanket frame pivotally carried at opposite ends by the cabinet end walls and a glass frame fioatably mounted upon the blanket frame and pivotable relative thereto, a bar member connected at one end to the glass frame to raise and lower the same independently of the blanket frame, said bar member carrying pin means thereon, a lever arm pivotally joined to the cabinet and connecting at its opposite end to the bar member to swing said member vertically and diagonally during pivotal movement of the glass frame, a looking mechanism connecting the glass frame to the blanket frame to prevent separation of said frames during tilting thereof, said locking mechanism including hook means engageable with the pin means lowering and locking the glass frame upon the blanket frame, vacuum means connecting with the blanket frame, an air locking mechanism securing the blanket frame to the cabinet and connecting with the vacuum means to release the frame from the cabinet when vacuum pressure has reached a predetermined point, and a lever mechanism connecting with the first locking mechanism and effective upon movement to lock the glass frame to the blanket frame and cause operation of the vacuum means and release of the blanket frame from the cabinet.

11. Apparatus for printing photographic plates and the like, comprising a cabinet structure including side and end walls, a frame assembly adapted to close the top of said cabinet and comprised of a blanket frame pivotally carried at opposite ends by the cabinet end walls and a glass frame floatably mounted upon the blanket frame and pivotable relative thereto, a bar member connected at one end to the glass frame to raise and lower the same independently of the blanket frame, a lever arm pivotally joined to the cabinet and connecting at its opposite end to the bar member to swing said member vertically and diagonally during pivotal movement of the glass frame, a locking mechanism connecting the glass frame to the blanket frame to prevent separation of said frames during tilting thereof, vacuum means connecting with the blanket frame, an air lock device on one of the cabinet walls, plate means on the blanket frame releasably engaged by the air lock device, a rotatable shaft extending between opposite end walls of the cabinet and connecting with the locking mechanism, and an operating lever rotating said shaft to lock the glass frame to the blanket frame and cause operation of the vacuum means and release of the air lock device from the plate means.

12. In combination with a vacuum blanket supporting frame and glass supporting frame pivotally mounted upon a framework, the improvement which comprises a source of vacuum, means connecting the vacuum source to the vacuum blanket, locking means on the framework conmeeting with the blanket, and plate means on the blanket supporting frame having a slot therein, said locking means comprising a housing, a shaft movable axially with respect to the housing, a diaphragm supported by the shaft and housing, and a spring in the housing normally urging the shaft into locking engagement with the slot in the plate means, said locking and plate means securing the blanket frame to the framework until a predetermined vacuum pressure has been drawn between the blanket and glass frames and thereupon releasing the blanket frame by axial movement of the locking means shaft to permit pivotal movement of said blanket frame.

References Cited in the file of this patent UNITED STATES PATENTS 2,117,051 Anderson May 10, 1938 2,494,282 Campbell Jan. 10, 1950 2,594,920 Halpern Apr. 29, 1952 2,718,181 Gullixson Sept. 20, 1955

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