US2905428A - Vacuum holder - Google Patents

Description

Sept. 22, 1959 R. E. RIBESEHL ETAL VACUUM HOLDER 5 Sheets-Sheet 1 Filed May 10. 1955 ATTORNEYS v Sept. 22,v 1959 R. E. RxBr-:SEHL ErAL 2,905,428

' VACUUM HOLDER Filed May 10, 1955 5 Sheets-Sheet 2 ATTORNEYS Sept. 22, 1959 R. E. RIBEsEHl. ETAL 2,905,428

VACUUM HOLDER 5 Sheets-Sheet 3 Filed May l0, 1955 INVENTORS 75er @fasse/,z

ATTORNEY/5 Sept. 22, 1959 R. RlBr-:sEl-n. ETAL 2,905,428

VACUUM HOLDER Filed May 1o. 1955 5 sheets-sheet 4 ATTQRNEY Sept. 22, 1959 R. E. RlBEsEHL EI'AL 2,905,428

VACUUM HOLDER 5 Sheets-Sheet 5 Filed May 10, 1955 ATTORNEY United States Patent() VACUUM HOLDER Robert iE. Riebesehl and Lloyd Halladay, Bellingham,

Wash., assignors to Bellingham Chain & Forge Company, Seattle, Walsh., a corporation of Washington ApplicationMay 10, 1955, Serial No. 507,263 4 claims. (cl. 24S-36s) This invention relates to improvements in devices for holding flexible sheet members in predetermined position by suction and more particularly to such devices adapted to hold fiexible sheets of sensitized film or copy material in photographic or reproducing processes.

It is an important .object of the present invention to provide improved holders of this type which support sheets of a variety of sizes in substantially flat condition free of wrinkles, bends and indentations.

It is a further object of the invention to provide vacnum holders of inexpensive yet rigid construction.

It is an additional object to provide improved vacuum holders which include a plurality of vacuum zones which are; selectively operated by a single readily accessible va ve.

It is also an object of the invention to provide vacuum Patented Sept. Z2, 1959 dictated by the size of the film or copy material with which the film board is used. In the present instance the board is approximately 27 inches by 35 inches so that it is capable of supporting all standard film sizes up to a film 20 inches by 24 inches.

The front face 16 of the supporting plate lit) is divided by Vgroove sets 2li-34 into zones of different size bounded by the respective groove sets. Each of the groove sets may be independently connected to a source of vacuum by means provided in the backing plate 12 and the control assembly 14 as described in detail below.

The groove set 20 preferably includes in addition to the grooves 36 and 38 extending longitudinally of the plate 10 and the grooves 40 and 42 extending laterally of the board, a pair of central grooves 44 and 46. The groove sets 22 32 preferably include a pair of grooves extending longitudinally of the plate connected at their opposite ends to a pair of grooves extending laterally of the plate. The groove set 34 preferably includes the grooves 48 and 50 extending laterally of the board which are connected at their opposite ends to short grooves 52 extending longitudinally of the board in alignment with grooves of the set 32.

In the embodiment of the invention shown, the groove sets are arranged to provide eight zones corresponding with the present standard film sizes namely 5 x 7, 8 x l0,

l 1,0 x12, ll X 14, 14x 17, 16 x 20,18 x22, and 20 x 24.

holders which have an extended trouble free service life Y and which are self cleaning in operation.

It is a further object to provide improved valves for controlling the selective operation of the several vacuum zones.

Additional objects and advantages will become apparent as the description proceeds in connection with the accompanying drawings in which:

Figure l is a front, elevation of a typical embodiment of the present invention;

Figure 2 is a fragmentary section taken along line 2 2 of Figure 1;

Figure 3 is a rear elevation of the apparatus of Figure 1 showing the single control element for the apparatus and with parts broken away to show details of Vconstruction;

Figure 4 is a front elevation of the backing member removed from the apparatus of Figure l to show details of the air channels;

Figure 5 is a fragmentary section taken along line 5 5 of Figure 1 illustrating details of the air channel construction;

Figures 6 and 7 are sectional views taken along lines 6 6 and 7 7, respectively, of Figure 2 illustrating details of the valve assembly;.and

Figure 8y is a fragmentary section taken along line 8 8 of Figure 7.

For conveniencethe novel support structure of the present invention may be termed a film board, this term being indicative of its primary utility. The principal components of the film board are the film supporting platev indicated generally at 10, `the back plate indicated generally at 12 and the Valve assembly indicated generally at V14. The plates 10 and 12 are sealingly secured by a plurality of screws 15. The supporting plate 10 comprises a. substantially fiat rectangular plate having finished flat front and rear surfaces 16 and 18, respectively. Since the supporting plate must have substantial rigidity and is necessarily formed to accurate dimensions it is preferably metallic although plastics or other materials satisfying these requirements may be used. The plate 10` may be vof any convenient size, the exact size being Preferably the Zone bounded by a particular groove set is slightly smaller than the film size involved. For ex ample, the zone bounded by the groove set 22 which is Aused to support 8 by l0 film sheets is 71/2 by 9%..

It is a feature of the invention that the grooves forming the several groove sets are very narrow, the width of these grooves preferably being within the range of .015 to .018". In a support plate of the size and type shown having a thickness in the neighborhood of 1A the grooves are preferably AG deep. The narrow grooves are uniquely effective in permitting the use of a relatively high vacuum to positively retain and position the film or other copy material on the support plate Without danger of causing the film or other highly fiexible material to sag or be depressed in the region of the grooves. In prior constructions utilizing wider grooves the degree of vacuum was necessarily greatly reduced to prevent this undesirable effect. Y

The depth of the grooves is suiiicient so that the grooves need be connected to a source of vaccum at only one or two widely spaced points along their length to insure distribution of a substantially uniform low pres= sure over the entire groove set when covered by a film or other flexible sheet.

A typical vacuum connection which places the groove sets in communication with the backing plate is shown in enlarged detail in Figure 5. The opening 54 there shown is preferably formed by sawing through the bottom of theassociated groove with a saw blade having substartially the same width as the groove and a relatively small radius, for example, three quarters of an inch. Preferably the cut forming the opening 54 is made sufiiciently deep so that the bottom of the opening is of substantial length for example, three quarters of an inch. Thus the openings 54 are of substantial size and because of the inclination of the side walls they have a self cleaning function and the problem of clogging commonly incurred in the prior artis thus eliminated.

As shown in Figure l the openings Se formed in each of the groove sets are disposed in a relatively narrow 3 connections, permits the use of a support plate of minimum size thus minimizing the material used in the backing plate and minimizing the area on the rear face of the support plate which must he machined hat to provide scaling contact between the film support plate and the back plate 12 thus effecting obvious manufacturing economies.

Each of the openings 54 is in communication with an aligned slot 56 formed in the front face of the backing plate 12. The slots 56 are preferably slightly wider and longer than the adjacent portion of the opening 54 to assure free communication between the openings 54 and the slots 56. In a typical example, these slots 56 are approximately one inch long, 1)/32 wide and JAG" deep. As shown in Figures l and 4, the openings 54 formed in the respective groove sets and the adjacent slots 56 are grouped in a substantially symmetrical pattern about the center of the plates 10 and 12. By virtue of this arrangement each of the groove sets is connected to a source of vacuum at diametrically opposed points to assure uniformity of distribution of the vacuum to the groove sets.

The slots 56 are intersected by slots 57--72 in communication, respectively, with through bores 73-88. It will be noted that the slots 59, 61, 63, 67 and 69 contain angularly related portions. These slots are formed in this manner to clear the adjacent ones of the bolts or screws sealingly securing the plate assemblies 10 and 12 together.

The bores 73-80 are formed on a common circumferential line about a central machined aperture 90 in the plate 12. The bores 81-88 are also formed on a common circumferential line about the aperture 90, the radius on which the bores 81-88 are formed being substantially smaller than the radius about which the bores 73-80 are formed.

rl`he respective bores 73-38 are connected to a source of vacuum by the unitary valve assembly 14 now to be described with particular reference to Figures 2, 3 and 6-8.

The valve assembly 14 comprises a housing 100 having a ange 102 adapted to be sealingly secured to the plate assemblies 10 and 12 by a plurality of headed screws 104. It will be noted that the flange 102 is positioned outwardly of the ports 731-88 so the hollow interior of the housing 100 eifectively forms a sealed chamber 106 about these ports at the rear of the plate assembly 12. A threaded connection 108 is provided in the side of the housing 100 to receive a vacuum connection so the pressure in chamber 106 may be reduced as desired.

Mounted within the chamber 106 and secured to the plate assembly 12 by means of screws 110 is a valve seat disk 112 provided with a series of through bores 114 in alignment with the respective bores 7S-8S in the plate assembly 12. Radial ports 115 connect the bores with the chamber 106. Provided in each of the bores 114 is a check valve assembly 116 comprising a resilient annular grommet 113 and a ball 120. The resilient grommets 11S, which are preferably of rubber, neoprene or the like, are provided with a central aperture 121 in alignment with the associated one of the bores 73-88, the apertures 121 thus being adapted to be closed by the balls 120 when the latter are urged inwardly against the grommets. In closing position the balls 120 are in sealing line contact with the adjacent end of the grommets aperture 121. When the housing 106 is connected to a source of vacuum the balls 120 are normally urged away from the grommets 118. The balls 120 are permitted to move away from the associated grommets to permit the flow of air into the chamber 106 through the radial ports 115 or are retained in sealing engagement with the grommets by the annular valve cam 122 which is non-rotatably secured by a pin 124 to an operating shaft 126i.

The valve cam 122 is provided with a pair ofparcuate cam surfaces 128 and 130, the center of the cam surface 123 being formed on the same radius as the ports 73--80 and the center of the earn surface 130 being formed on the same radius as the ports 81-88. The cams 12S-130 are of uniform height except at their opposite ends where they merge into the surface of the cam body through an inclined portion'131 shown in Figure 8. The length of the cam portions at uniform height is such that the cam disc 122 may be positioned so the ca ms simultaneously engage each of the balls 120 and thus close each of the ports in the plate assembly 12, to establish the off position of the valve assembly 14. The cam disc 122 may be rotated away from this position by rotation of the shaft 126 mounted at its opposite ends in bushings 134 and 136, the former being mounted in the aperture 90 in the plate assembly 20 and an aligned aperture 138 in the valve disc 112 and the latter being mounted in an aligned aperture 140 in the housing 100, the aperture being closed by a sealing O-ring 142. The shaft 126 extends out of the housing 100 and is there connected as by a set screw 144 to an operating assembly 146 provided with a handle 150.

A thrust bearing assembly 152 is positioned between the rear side of the cam disc 122 and a pressure plate 154, the latter being adjustably positioned by screws 156. Accordingly, the pressure by which the valve assemblies 116 are held closed may be regulated by adjustment of the screws 156 before assembly of the assembly 146 to the shaft 126.

It will be seen that the ports 73-80 and 81-88 are so arranged with respect to the cams 12S and 130 that rotary movement of the cam disc 122 will simultaneously open and close pairs of these respective ports. For eX- ample, referring to Figure 4, if the cam disc 122 is moved in a clockwise direction as viewed in Figure 3 from the off position, the ports 73 and 81 will be opened simultaneously. Further movement of the disc 122 will simultaneously open the ports 74 and 82, the ports '73 and 81 previously opened remaining open. As the clockwise movement of the disc 122 is continued additional pairs of ports will be opened and in each case the pairs of ports previously opened will remain opened. Finally when the disc is moved substantially 180 in a counterclockwise direction from its initial or off position all of the ports will be opened. The valve as shown in Figure 3 occupies an intermediate position, 90 from the oif position.

Referring again to Figures 1 and 3 it will be seen that opening of the ports 73 and 81 connects the inner groove set 20 to a source of vacuum through the slots 54 in the groove 46 and that subsequent opening of the ports 74, 82, etc. and 75, 83 sequentially connects the groove sets 22, 24 and 26, etc. to the source of vacuum. Accordingly as the zones bounded by the increasingly larger groove sets are connected to vacuum all of the inner zones will also be so connected. Thus when the groove set 34 is connected to vacuum to support the largest sheet of hn y which the present mechanism is adapted to handle the film will be supported substantially over its entire surface by the inner groove sets as well as the outer most groove set 34. Conversely when the size of the sheet is such that for example only the groove set 20 is covered by the sheet, the remaining groove sets will be disconnected from the vacuum source.

1t is a particular feature of the invention that the desired zones are rendered operative or inoperative through the operation of the single handle 150. For further convenience in operation, cooperating indicia may be applied on the handle assembly 146 and the housing to indicate the largest zone rendered operativo by a particular setting of the handle 150. A suitable detent mechanism indicated generally at 160 is mounted in the side of the housing 100 and has a retractable plunger 162 cooperating with suitably positioned notches 164 in the periphery of the disc 122 to facilitate positioning of the disc and to retain it in the several positions corresponding to the lilm size involved.

From the foregoing it will be apparent that the abovestated objects of the invention have been obtained by the provision of a film board of simple, durable construction `which is effective to support flexible sheets in a wide range of sizes in a substantially flat condition. Through the provision of the unique unitary valve assembly, control of the `size of the operative vacuum zone is easily and positively effected. Further, the board is self-cleaning and oifers an extended trouble-free service life.

The invention may be embodied in other specic forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative `and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. Support structure for sheets of film, paper and the like comprising a support plate having a substantially at front face and a smooth planar rear face, sets of grooves in the front face of said plate positioned substantially symmetrically about the center of said plate, said groove sets defining substantially concentric zones of predetermined size on said plate, apertures connecting each of said groove sets at points spaced substantially symmetrically about the center of said support structure with the rear face of said support plate, said apertures comprising the sole connection between the front and rear faces of said plate, a backing plate sealingly secured directly to the rear face of said support plate and in surface contact therewith, a plurality of openings extending through said backing plate substantially centrally thereof, slots in the face of said backing plate contacting said support plate, said slots extending radially outwardly from said openings and each of said slots directly connecting an opening in said backing plate with an aperture in said support plate, and valve means for selectively connecting one of the openings leading to a predetermined zone to a source of vacuum while also connecting each of said openings leading to zones within said predetermined zone to a source of vacuum.

2. Support structure for sheets of lm, paper and the like comprising a support plate having a substantially flat front face, a backing plate, means sealingly securing said plates together with the front face of Said backing plate in full surface contact with the rear face of said support plate, channels in the front face of each of said plates, said channels in the front face of said support plate bounding rectangular concentric zones on said support plate and the channels in the front face of said backing plate extending radially outward from a central portion of said backing plate, openings in said support plate connecting certain of said channels in said supporting plate to certain of said channels in said backing plate at points spaced substantially symmetrical about the center of said support structure, a housing sealingly secured directly to the rear surface of said backing plate and adapted tol be connected to a source of vacuum, and separate valve means in said housing connecting each of said channels in said backing plate with the interior of said housing. y 3. Support structure according to claim 2 together with the val-ve control element for operating said valve means in predetermined sequence to connect a predetermined one of said zones to vacuum While also connecting all the zones inwardly of said predetermined zone to vacuum.

4. Supporting structure for sheets of film, paper and the like comprising, a support plate having a sheet supporting surface, sets of grooves in said surface of said plate deining concentric zones of predetermined size in said plate, said zones being arranged substantially symmetrically with respect to the center of said plate, separate passage means adapted to connect each of said groove sets to a source of vacuum at points spaced sub stantially symmetrically about the center of said support structure, a separate valve in each of said passage means, and a unitary valve control element for operating said valves in a manner toconnect any predetermined zone to a source of Vacuum while also connecting all of the zones inwardly of said predetermined zone to a source of vacuum.

References Cited in the le of this patent UNITED STATES PATENTS 1,725,280 Kiefer Aug. 20, 1929 1,945,481 Dilkes Jan. 30, 1934 1,945,493 Martindell Jan. 30, 1934 1,971,382 Petersen Aug. 28, 1934 1,980,144 Liena Nofv. 6, 1934 2,317,348 Wekeman Apr. 27, 1943 2,519,610 Sussin Aug. 22, 1950 2,572,640 Lovegrove Oct. 23, 1951 2,575,940 Brown Nov. 20, 1951 2,717,756 Keeshan et al. Sept. 13, 1955 2,732,859 Chace Jan. 31, 1956 2,769,459 Birkness et al. Nov. 6, 1956 FOREIGN PATENTS 347,776 Germany Ian. 26, 1922

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