US3907268A

US3907268A - Valve means for vacuum holding device

Info

Publication number: US3907268A
Application number: US456060A
Authority: US
Inventors: Thomas F Hale
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-03-29
Filing date: 1974-03-29
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23
Also published as: DE2513769C2; FI62240B; DK142452C; NL159905C; AR203902A1; JPS50131178A; NO138513B; CA1011351A; DK142452B; GB1453918A; NL159905B; NL7503439A; DK124475A; NO138513C; JPS5513856B2; AU7892775A; SE7503573L; NO750836L; FI750911A; DE2513769A1

Abstract

In a vacuum holding device for holding items comprising a vacuum source, at least one vacuum cell plate providing a front surface against which items are held, the cell plate providing a plurality of cell areas in the front surface, and conduits for connecting the cell areas to the vacuum source, the improvement comprising, for each cell area, a valve structure effective to open the cell area to the vacuum source only when the cell area is completely covered by an item such that a vacuum can form therein.

Description

United States Patent Hale Sept. 23, 1975 [54] EQL Y FOR VACUUM HOLDING FOREIGN PATENTS OR APPLICATIONS C 146,868 1954 Sweden 269/21 [76] Inventor: Thomas F. Hale, P.O. Box 15, New

y 47150 Primary ExaminerGranville Y. Custer. Jr. 22 Filed: Mar. 29 1974 Assistant ExaminerMark S. BlCkS Attorney, Agent, or FirmWilliam R. Coffey [21] Appl. N0.: 456,060

[57] ABSTRACT [52] U.S. Cl.2 269/21 In a Vacuum holding device for holding items compris [51] Int. Cl. B25B 11/00 ing a vacuum, Source, at least one vacuum Ce plate [58] Field of Search 51/235; 248/362, 363; providing a front surface against which items are held, 269/21; 279/3 the cell late rovidin a plurality of cell areas in the P P g front surface, and conduits for connecting the cell [56] References C'ted areas to the vacuum source, the improvement com- UNITED STATES PATENTS prising, for each cell area, a valve structure effective 2,782,574 2/1957 Copold 269/21 to p the Cell area to the vacuum Source y when 2,910,265 10/1959 Ananderm, 248/363 the cell area is completely covered by an item such 2,998,256 8/1961 Lipkins 1 51/235 that a vacuum can form therein. 3,307,817 3/1967 Cocito 248/362 3,335,994 8/1967 Cocito 248/363 27 Clalms, 9 Drawmg Flgures 78 l 08 I26 I12 106 /||o 94 l 1 1 I I I I I I H W Q) E 80 "-1- n I 1 82 I28 I02 lo'o/lss/ 152130 US Patent Sept. 23,1975 Sheet 2 of3 3,907,268

mommmxnzzoo E4 US Patent Sept. 23,1975 Sheet 3 of3 3,907,268

IIIIIII'III VALVE MEANS FOR VACUUM HOLDING DEVICE l am aware of a company which presently is offering to sell vacuum systems for holding flitches on flitch tables of veneer slicers. While my knowledge about such systems is limited, I believe my present invention constitutes a very substantial advantage over the systems being offered. For instance, I understand that the system being offered for flitch tables comprises a plurality of ports in a rubber or rubberoid mat, which ports are connected to a vacuum source. A flitch is placed against the mat to cover only a portion of the ports because of the irregular shapes and sizes of the flitches. The covered ports are evacuated by the pumping action and thus to grip the flitches. Those ports which are not covered or completely covered by the flitches are left open to the vacuum source. Such a system, therefore, involves a tremendous amount of air flow and pumping capacity, thereby requiring extensive vacuum pumping equipment.

My system comprises a vacuum source such as a vacuum pump and at least one vacuum cell plate providing a front surface against which an item to be held is placed and one or more'cell areas in the front surface. Sealing means extends about each cell area. Conduit means are provided for connecting each cell area to the vacuum source, the conduit means including, for each cell area, valve means. Each said valve means includes actuating means for' determining when its associated cell area is completely covered by an item to be held and opening the cell area to the vacuum source only when it is completely covered by the item.

Specifically, the vacuum means of my present invention includes a plurality of cell areas with valve means associated with each cell area and arranged to open each cell area to the vacuum source only when the cell area is completely covered such that it can be evacuated.

in a preferred embodiment of my invention, each valve means includes means providing a valve passageway having a first seat therein, and'a valve member movable against the first seat to close the passageway, thereby closing its associated cell area to the vacuum source. The actuating means includes means for holding the valve member away from the first seat and releasing the valve member for movement against the first seat when the cell area is not completely covered such that a vacuum can form therein. In a preferred embodiment, each actuating means includes an air actuated plunger for moving the valve member, a source of compressed air, and conduit means'for connecting the plunger to the source of compressed air. This conduit means preferably includes valve means for simultaneously supplying air under pressure to the plungers and simultaneously exhausting the air from the plungers as well as selectively variable orifice means through which air under pressure is exhausted, whereby the speed of movement of the plungers in releasing the valve members is controlled. In this embodiment, the valve passageway also provides a second seat spaced apart from the first valve seat, the valve member being movable between the seats and movable against the second seat to close the passageway. The actuating means is effective to move the valve member against the said second seat and to hold it there while an item to be held is being placed against the front surface of the cell plate and to release the valve member for movement toward the first valve seat when the item is against the front surface. I

ln a preferred embodiment of the present invention, eachcell plate provides a back surface having a plurality of cavities therein in registry respectively with the cell areas and a rubber diaphragm covering the back surface and the cavities. The aforesaid conduit means for the compressed air includes a base plate having air passageways formed therein, portions of which overlie the cavities such that positive air pressure in the passageways deflect the portions of the diaphragm overlying the cavities. The plungers are yieldably urged against the diaphragm deflecting portions to be moved by the portions when positive air pressure is applied to the air passageways.

While I have illustrated and described an air compressor system for deflecting the diaphragm portions overlying the cavities, it will readily be appreciated that such portions may also be deflected by hydraulic pressure supplied by hydraulic pump instead of an air compressor. It will also be appreciated that any number of different types of pneumatic or hydraulic plungers may be used with the cell areas to move the valve members.

Further, it will be appreciated that I may provide a solenoid-actuated plunger or actuating means for each cell area.

Still another object of my invention is to provide a vacuum system for holding irregularly-shaped items to a support means, the system comprising a vacuum pump, means providing a plurality of cell areas against which the items are held, sealing means bounding each cell area sealably to engage the items, valve means for connecting each cell area to the vacuum pump, each valve means including means providing a valve passageway communicating between its associated cell area and the vacuum pump, a valve member for closing the passageway, and means for actuating the valve member to keep the passageway open when its associated cell area is completely covered by an item and a vacuum is formed in the covered cell area and closed when the cell area is not completely covered such that a vacuum can form. In a preferred embodiment of this invention, the valve member and the passageways are proportioned and designed such that, when the cell area is completely covered and evacuated, the pressure on opposite sides of the valve member is equalized such that the valve member, when released, will not move to its closing position. If the cell area is not completely covered, the movement of air from the cell area through the valve passageway will move the valve member into sealing engagement with a valve seat, i.e., to its valve closing position.

The system of my present invention is ideally suited for holding items of different sizes and shapes to a support means. It is relatively easy to construct a vacuum holding system for holding items which are of the same size and shape. All that is necessary, in that case, is to provide one or more cell areas which will be completely covered by the uniform items and then connect such cell areas to a vacuum source. There are many applications, however, where the items to be picked up or held have different sizes and shapes. For instance, logs which are cut into flitches for slicing in a veneer mill will have different lengths and the back surfaces of the flitches will have different shapes. The slices of veneer coming from such flitches will also have different shapes and sizes. In sawmills, for instance, boards sliced from logs will have different shapes and sizes.

It is within the scope of my present invention to have a cell plate providing one or more cell areas which may be large or small as required for the particular application. There may be one or more such cell plates. Each cell area, however, is provided with valve means which will open the cell area to the vacuum source only when the cell area is completely covered such that it can be evacuated. The cell areas may be defined in any number of different ways. Sealing means may extend about each cell area sealably to engage the item to be held. The cell areas may be defined, for instance, by forming openings in a large rubber or rubberoid mat which is adhesively or otherwise secured to a plate structure.

Other objects and features of the present invention will become apparent as this description progresses.

To the accomplishment of the above and related objects, this invention may be embodied in the forms illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific constructions illustrated and described, so long as the scope of the appended claims is not violated.

In the drawings:

FIG. 1 is a view of a small vacuum cell plate for illustration purposes;

FIG. 2 is a fragmentary sectional view of the valve associated with one cell area;

FIG. 3 is a fragmentary sectional view of the plate of FIG. 1 showing one cell area and its valve;

FIG. 4 is an enlarged diagrammatic view showing how the valve ball closes the valve passageway;

FIG. 5 is a fragmentary sectional view showing the structure of FIG. 3 as adapted for use on horizontal cell plates;

FIG. 6 is a diagrammatical view of the system of either FIGS. 3 or 5;

FIG. 7 is a block diagram of the system of the present invention;

FIG. 8 is a fragmentary sectional view showing my presently preferred type of cell area and valve means; and

FIG. 9 is a fragmentary view of the rubber mat which covers the cell plate to provide sealing means bounding each cell area.

Turning now to FIGS. 1-5, it will be seen that the illustrative plate 70a includes a center plate 80, base plate 82 and screws 84 for holding the base plate to the center plate. A cover plate 86 for each cell area is secured to the center plate by a screw such as indicated at 88. The areas outside the cell area may be covered by a front plate 90 which is secured to the center plate, for instance, by the screws 92. The edges of the cell cover plates 86 are formed as shown in the sectional views of FIGS. 3 and 5 to accommodate a gasket 78 which is trapezoidal in cross section. While I show such gaskets having such cross sections, I have successfully used gaskets which are rectangular in cross section. I have also successfully used such gaskets which are adhesively attached to the front surface of the center plate 80.

It will be understood that the view of FIG. 3 is oriented out of position in that the

plates

80, 82, 90 will extend vertically when they are attached to a system. In FIG. 5, however, the illustrative structure is designed for use on a horizontal system. The differences between the FIG. 5 structure and the FIG. 3 structure will become apparent as this description progresses.

Each illustrative cell area 76 may be provided with a dogging pin 94, the outer portion of which is sharpened to dig into the item held thereagainst. The multitude of dogging pins serve to keep the item from shifting on the cell plate. The force of the vacuum system pulls the held item into engagement with the dogging pins. The illustrative dogging pin 94 is a rigid sharpened pin, the shank portion of which extends through openings in the cell cover plate 86 and the center plate 80. It will be appreciated that such dogging pins are ideal for engaging wooden items being held.

A rubber sheet or diaphragm 96 is disposed between the plate 80 and the base plate 82 to overlie passageways and/or cavities forcompressed air formed in the base plate 82. A cavity 100 is formed in the back surface of the plate 80 to be in registry with a valve passageway to be described hereinafter. Each cavity 100 is in registry with a cavity or portion of a passageway 98 in the base plate 82. Passageways 102 are formed in the center plate 80 to connect the cavities 100 to the vacuum pumping source.

As this description progresses, it will be appreciated that many conduits and passageways are necessary to connect the vacuum pump and the air compressor to the cell areas. Such conduits and passageways come under the broad heading of conduit means. In other words, the positive air pressure cavities in the plate 82 may be connected to the air compressor by passageways formed in the plate as well as tubing and hoses while the vacuum cavities 100 formed in the plate 80 may be connected to the vacuum pump by passageways such as indicated at 102, tubes and hoses. I find it convenient to mill slots and cavities in the

plates

80, 82 to form the connecting passageways.

Each cell cover plate 86 is formed with a valve opening 104 bounded by a rabbet 106 and which is in registry with a threaded opening 108 providing communication with the cavity 100. Each cell area 76 includes valve means as mentioned heretofore. The valve means of FIGS. 2, 3 and 4 comprises a valve body 110 having a flange 112 received in the rabbet 106 and a valve passageway 114 extending coaxially therethrough. The valve passageway 1 14 is formed to provide a first conical valve seat 1 16 in the passageway, and the outer end of the passageway 114 is threaded as indicated at 118. An orifice member is threaded into the outer end of the passageway 114, and it provides an opening 122 therethrough which is in registry with the passageway. The opening 122 may be a hexagonal opening to fit an Allen wrench used to secure the orifice member into position. The orifice member 120 is formed to provide a second conical valve seat 124 spaced apart from the valve seat 1l6.'A valve ball 126, which may be a rubber ball, is disposed in the passageway 114 for movement between the

seats

116, 124. The ball 126 will sealably engage either

seat

116, 124 to close the passageway 114. The diameter of the passageway 114 and the distance between the seats is greater than the diameter of the ball 126 such that, when the ball 126 is not engaged with either seat, air movement through the passageway 114 is possible. FIG. 2 shows the ball 126 when it is in its nonclosing position, FIG. 3 shows the ball against the seat 116 and FIG. 4 shows the ball against the seat 124.

The illustrative valve means includes actuating means for determining when its associated cell area 76 is completely covered by an item and opening the cell area to the vacuum pump only when it is completely covered by the item. The illustrative actuating means includes a plunger 128 which may be, for instance, the shank of a screw. A nut 130 and a cupped washer 132 are placed upon the shank of the screw on one side of the diaphragm while the head 134 of the screw and a flat washer 136 are on the other side of the diaphragm. The nut 130 is tightened such that the screw moves when the diaphragm portion overlying the cavity 100 and the cavity 98 is deflected. A spring 138 is provided for urging the shank 128 away from the ball 126, i.e., to its ball releasing position. When compressed air is admitted to the cavity 98, the portion of the diaphragm 96 in registry therewith is deflected toward the ball 126 such that the shank 128 will engage the ball and move it against the seat 124 to close the passageway 1 14. The cavity 100 is evacuated because it is connected to the vacuum pump. The ball 126 is held against the seat 124 until the item to be held is placed against the cell plate.

-When the item is securely against the cell plate, the

positive air pressure is released from the cavity 98 to permit the spring 138 to move the plunger away from the ball 126. If the cell area is completely covered by the item such that a vacuum can form within the cell area, i.e., in the space bound by the gasket 78, there will not be sufficient air flow from the cell area through the valve passageway to move the ball 126 against the seat 116. In such a case, the ball will simply drop downwardly to its position shown in FIG. 2 such that the cell area is open to the vacuum pump.

If the cell area is not completely covered, when the plunger 128 is moved away from the ball 126 so that the ball can move away from the seat 124, the movement of air through the opening 122 will be sufficient to move the ball 126 against the seat 116 to close the passageway 114, i.e., to close the cell area to the vacuum pump.

In either case, only a small amount of air will flow through the valve passageway 114. If the cell area is completely covered, only the air which is required to evacuate the cell area will move through the passageway. If the passageway is not completely covered, the ball 126 will move against the seat 116 to close the passageway rather quickly to stop the air flow. My system, therefore, can operate with a relatively small capacity vacuum pump. Only those cell areas which are completely covered will be open to the vacuum pump. Those cell areas not completely covered will be closed by their respective valves so as not to introduce any significant air flow into the vacuum system.

It will be appreciated that by using the diaphragm 96 between the cavities and passageways in the

plates

80, 82, I can simultaneously move a plurality of valve balls 126 against the seats 124 and then later, when an item to be held is against the cell plate, simultaneously move the plungers 128 to release the valve balls for movement either to their FIG. 2 or their FIG. 4 positions, depending upon whether or not their cell areas are completely covered. As discussed in conjunction with FIGS. 6 and 7, I release the positive air pressure through a selectively variable orifice means so that I can control the speed of movement of the plungers 128 in releasing the balls 126 for movement away from the seats 124. By controlling the releasing of the balls 126, I can time the system such that the balls will not quickly jump to close against the seats 116 even if the cell areas are completely covered.

Turning now to FIG. 5, it will be seen that the illustrative valve means includes a valve body 152 similar to valve body 110 and providing a passageway 154 with facing conical seats 156, 158. A ball is disposed between the valve seats in the passageway 154. The ball 160 will seal against either seat to close the passageway, and it will stay between the seats to permit air movement through the passageway. Since the structure of FIG. 5 is ideally suited for a horizontal system, a vertically upwar'dly extending plunger 162 is mounted on a cup 164 which rests on the adjacent deflecting portion of the diaphragm 96. A spring 166 urges the cup 164 and its plunger 162 downwardly. I then provide an inner spring 168 which is coiled about the plunger and which is calibrated such that it supports the ball 160 in its position between the seats 156, 158 when the cell area 76 is completely covered such that a vacuum can form therein. When the cell area is not completely covered, the movement of the air from the cell area through the passageway 154 will move the ball against the urging of the spring 168 downwardly to close against the seat 156. Diagrammatically, I show an air compressor 170 and a conduit 172 connecting the air compressor to an annular passageway 174 which defines also a seat 176 for the diaphragm deflecting portion. When compressed air is injected into the annular passageway 174, the plunger 162 will be moved upwardly to move the ball 160 against the seat 158 for the same reasons'discussed in conjunction with FIGS. 2, 3 and 4.

The structure of FIG. 5 can be described in its various conditions of operation. The first condition is when the structure is ready for loading. A vacuum is established in the cavity 178 in communication with or in registry with the valve passageway 154 pulling the ball 160 downwardly. on the seat 156. Atmospheric pressure is present in the annular chamber 174 in the base plate. The second condition involves a change in phase because positive air pressure is supplied to the lower chamber moving the plunger 162 upwardly to raise the ball 160 from its lower seat to hold it against the upper seat 158 resealing the system. The third condition then depends upon whether or not the cell area is completely coverd. If the cell area is completely covered, when the plunger 162 is released for movement by the spring 166, the ball 160 drops from the upper seat 158 to permit only a slight flow from the covered cell area through the valve passageway insufficient to cause the ball to reseal against the lower seat 156. That situation creates a vacuum or a negative pressure in the cell area space surrounded by the gasket 78 and covered by the item to be held. The negative pressure in the cavity 178 will be equal to the negative pressure in the cell area such that the inner spring 168 will merely hold the ball 160 between its two seats 156, 158.

If the cell area is not completely covered by the item to be held when the positive air pressure in the annular passageway 174 is released, air flow occurs through the valve passageway sufficient to cause the ball 160 to reseat against the lower seat 156, thereby closing the valve passageway completely and closing the cell area to the vacuum source.

Note that in either third condition, no flow above that necessary to close the valve 150 can exist. The structures for the horizontal and vertical systems are similar in this respect. For vertical systems, the ball 126 merely drops downwardly as shown in FIG. 2 when a vacuum is formed in the associated cell area while the ball 160 for horizontal systems will merely be supported between the seats by the calibrated spring 168 when a vacuum is formed in the associated cell area.

In FIG. 6, I show the system of FIG. 5 diagrammatically illustrating a vacuum pump 180 and a control valve 182 through which the pump is connected to the passageway 102. I also show a control valve 184 through which the air compressor 170 is connected to the conduit 172 leading to the annular passageway 174. I also show the selectively variable orifice means 186 through which the compressed air in the annular passageway 174 is released, the orifice means being controllable to control the speed with which the plunger 162 is moved to release the ball 160.

FIG. 7 is a very diagrammatical view showing in block form a plurality of cell areas 76, each of which is bounded by sealing means 78 and each of which is equipped with valve means 150. Each valve means 150 includes an actuating means connected to an air compressor 170 through a control valve 184 which leads to a variable orifice means 186. Each valve means is also connected to a vacuum source 180 through a control valve 182. The control valve 182 may be released, for instance, to release a held item from the cell plate. While I show only three cell areas 76, it will be appreciated that my preferred vacuum system may include one or more or even hundreds of such cell areas.

Referring now to FIGS. 8 and 9, I will describe another of my preferred embodiments of the present invention. The embodiment of FIG. 8 is quite similar to the embodiment of FIGS. 2-4 and the valve means of the embodiment of FIG. 8 functions in the same manner as the valve means of FIGS. 24. The structure shown in FIG. 8, which is for a vertical system, comprises a front plate 260, diaphragm retainer plate 262, rubber or rubber-like diaphragm 264, and base plate 266. A rubber mat 268 having cell areas 270 punched therefrom is adhesively or otherwise secured to the front surface of the plate 260. FIG. 9 shows a portion of such a rubber mat with the illustrative arrangement of the cell areas therein, each cell area being an ellipse which has a major diameter of two inches and a minor diameter of l A; inch. A great number of cell area sizes and shapes may be used.

For each cell area 270, a cylindrical opening 272 is formed in the plate 260, the outer portion of which is threaded as indicated at 274. A passageway 276 for compressed air is provided in the base plate 266. The passageway 276 may preferably be a milled slot serving several cell areas. The diaphragm retainer plate 262 is provided with a circular opening 278 in registry with the opening 272 such that only a circular portion of the diaphragm 264 is deflected. A valve body 280 is threaded into the opening 272 as illustrated, the valve body providing a portion 282 projecting outwardly from the front surface of the plate 265?. A harpened dog ring 284 including a plurality of p. npherally spaced apart outwardly projecting points may be provided for engaging the item to be held and holding the item against movement in the direction of the front surface of the plate 260. The valve body 280 has a peripherally and radially outwardly extending flange 286 which engages against the front surface of the plate 260 and which compresses a ring seal to seal the valve body to the plate.

The valve body 280 has a coaxial threaded bore 290 and an opening 292 providing communication between the cell area 270 and the threaded bore 290. An orifice member 294 is threadedly engaged into the bore 290 as illustrated, and it provides a first conical valve seat 296. The second conical valve seat 298 is provided by the valve body 280. A valve ball 300 is engageable with each

seat

296, 298 as discussed previously. The ball may also fall down between the two seats to open the valve passageway. The orifice member 294 is provided with a coaxial bore 302 through which a plunger 304 moves. The plunger is part of the actuating means which moves the ball 300 away from the valve seat 296 during the process of mounting the item to be held. The plunger 304 is carried by a cup 306, and a coiled compression spring 308 is used to urge the cup and the plunger to the ball releasing position.

I claim:

1. In a device for holding items comprising support means upon which items are held, the improvement comprising vacuum means for holding items to the support means, said vacuum means including a vacuum source, at least one vacuum cell plate mounted on said support means, said cell plate providing a front surface against which such items are held, said cell plate providing a plurality of cell areas in said front surface, sealing means extending about each cell area, and conduit means for connecting said cell areas to said vacuum source, said conduit means including, for each cell area, valve means, each said valve means including means providing a valve passageway having a first valve seat therein, and a valve member movable against said first valve seat to close said passageway, thereby closing its associated cell area to said vacuum source, and actuating means for determining when its associated cell area is completely covered by an item and opening said cell area to said vacuum source only when it is completely covered by an item, said actuating means including means for holding said valve member away from said first valve seat and then disengaging said valve member for movement against said first valve seat solely by the movement of air from said cell area when said cell area is not completely covered such that a vacuum can form therein.

2. In a device for holding items comprising support means upon which items are held, the improvement comprising vacuum means for holding items to the Support means, said vacuum means including a vacuum source, at least one vacuum cell plate mounted on said support means, said cell plate providing a front surface against which such items are held, said cell plate providing a plurality of cell areas in said front surface, sealing means extending about each cell area, and conduit means for connecting said cell areas to said vacuum source, said conduit means including, for each cell area, valve means, each said valve means including means providing a valve passageway having a first valve seat therein, and a valve member movable against said first valve seat to close said passageway, thereby closing its associated cell area to said vacuum source, and actuating means for determining when its associated cell area is completely covered by an item and opening said cell area to said vacuum source only when it is completely covered by an item, said actuating means including means for holding said valve member away from said first valve seat and releasing said valve member for movement against said first valve seat when said cell area is not completely covered such that a vacuum can form therein, said passageway providing a second valve seat spaced apart from said first valve seat, said valve member being movable between said seats and movable against said second seat to close said passageway, said actuating means being effective to move said valve member against said second seat and hold it there while an item to be held is being placed against said front surface and to release said valve member for movement toward said first valve seat when the item is against said front surface.

3. The improvement of claim 2 in which said valve member is a spherical ball having a first diameter, said passageway being cylindrical and having a second and greater diameter, said valve seats being conical and facing each other, whereby when the associated cell area is completely covered such that a vacuum is formed therein, said ball stays out of engagement with said seats to open said cell area to said vacuum source.

4. The improvement of claim 3 in which each actuating means includes an air actuated plunger for moving its associated ball against said second valve seat, holding it there, and releasing it for movement toward said first valve seat, a source of compressed air, and conduit means connecting said plungers to said source of compressed air.

5. The improvement of claim 4 in which each actuating means includes spring means for yieldably urging its associated plunger to its retracted, ball releasing position, the compressed air conduit means including valve means for supplying air under pressure to said plungers and exhausting the air from said plungers, and selec-' tively variable orifice means through which the air under pressure is controlled and by which the speed of movement of the plungers in releasing the balls is controlled.

6. In a device for holding items comprising support means upon which items are held, the improvement comprising vacuum means for holding items to the support means, said vacuum means including a vacuum source, at least one vacuum cell plate mounted on said support means, said cell plate providing a front surface against which such items are held, said cell plate providing a plurality of cell areas in said front surface, sealing means extending about each cell area, and conduit means for connecting said cell areas to said vacuum source, said conduit means including, for each cell area, valve means, each said valve means including means providing a valve passageway having a first valve seat therein, and a valve member movable against said first valve seat to close said passageway, thereby closing its associated cell area to said vacuum source, and actuating means for determining when its associated cell area is completely covered by an item and opening said cell area to said vacuum source only when it is completely covered by an item, said actuating means including means for holding said valve member away from said first valve seat and releasing said valve member for movement against said first valve seat when said cell area is not completely covered such that a vacuum can form therein, each actuating means including an air actuated plunger for moving said valve member, a source of compressed air, and conduit means connecting said plungers to said source of compressed air,

7. The improvement of claim 6 in which said conduit means includes valve means for supplying air under pressure to said plungers and exhausting the air from said plungers, said conduit means including selectively variable orifice means through which the air under pressure is exhausted, whereby the speed of movement of said plungers in releasing said valve members is controlled.

8. The improvement of claim 6 in which said cell plate provides a back surface having a plurality of cavities therein in registry respectively with said cell areas, a rubber diaphragm covering said back surface and said cavities, said conduit means for the compressed air including a base plate having air passageways formed therein, portions of which overlie said cavities, whereby positive air pressure in said passageways deflects the portions of said diaphragm overlying said cavities, said plungers being movable by said deflecting diaphragm portions, and spring means for yieldably resisting movement of said plungers by said diaphragm portions.

9. In a device for holding items comprising support means upon which items are held, the improvement comprising a vacuum system for holding items to said support means, said system comprising a vacuum pump, means providing at least one cell area against which items are held, sealing means bounding said cell area sealably to engage the item, valve means for connecting said cell area to said vacuum pump, said valve means including means providing a valve passageway communicating between said cell area and said vacuum pump, a valve member for closing said passageway, and plunger means for shifting said valve member away from its position closing said passageway and then disengaging said valve member for movement controlled solely by the air flow from the cell area through said passageway, the air flow being insufficient to move the valve member to its closing position when the cell area is completely covered.

10. In a device for holding items comprising support means upon which items are held, the improvement comprising a vacuum system for holding items to said support means, said system comprising a vacuum pump, means providing at least one cell area against which items are held, sealing means bounding said cell area sealably to engage the item, valve means for connecting said cell area to said vacuum pump, said valve means including means providing a valve passageway communicating between said cell area and said vacuum pump, a valve member for closing said passageway, and plunger means for actuating said valve member to keep said passageway open when said cell area is completely covered by an item and a vacuum is formed in the covered cell area and closed when the cell area is not completely covered by an item such that a vacuum can form, said plunger means including an air actuated plunger for moving said valve member, a source of compressed air, and conduit means connecting said plunger to said source of compressed air.

11. The improvement of claim in which said valve means is proportioned such that its said valve member has a closing position in said passageway, said plunger being effective to move said valve member away from its closing position, to hold it away from its closing position while an item is being placed against the cell area, and to release said valve member for movement toward its closing position when the item is against the cell area.

12. The improvement of claim 11 in which said valve member and said passageway are proportioned and designed such that, when the cell area is completely covered and evacuated, the pressure on opposite sides of said valve member is equalized such that said valve member, when released, will not move to its closing position.

13. The improvement of claim 11 including selectively variable orifice means for exhausting the compressed air from said conduit means to control the speed of movement of said plunger in releasing said valve member for movement toward its closing position.

14. The improvement of claim 11 including spring means for yieldably urging said plunger toward its releasing position.

15. In a device for holding items comprising support means upon which items are held, the improvement comprising a vacuum system for holding items to said support means, said system comprising a vacuum pump, means providing at least one cell area against which items are held, sealing means bounding said cell area sealably to engage the item, valve means for connecting said cell area to said vacuum pump, said valve means including means providing a valve passageway communicating between said cell area and said vacuum pump, a valve member for closing said passageway, and plunger means for actuating said valve member to keep said passageway open when said cell area is completely covered by an item and a vacuum is formed in the covered cell area and closed when the cell area is not completely covered by an item such that a vacuum can form, said means providing at least one cell area providing a plurality of said cell areas and associated valve means and including at least one cell plate providing a front surface including said cell areas and a back surface, said back surface having a plurality of cavities therein in registry, respectively, with said cell areas, said valve passageways of said valve means communicating respectively between said cell areas and said cavities, said actuating means including a diaphragm covering said back surface and said cavities, a base plate covering said diaphragm, said base plate having air passageways therein, portions of which overlie said cavities, a source of compressed air and means for connecting said source of compressed air to the passageways in said base plate, whereby compressed air in said passageways will deflect the portions of said diaphragm overlying said cavities, and plungers in said cavities movable by said deflecting diaphragm portions to move said valve members.

16. The improvement of claim 15 in which each valve passageway has a first conical valve seat facing the associated cell area and an axially spaced apart second conical valve seat facing said first valve seat, said valve member being a spherical ball movable between and engageable with said seats, said passageway having a diameter greater than said ball such that said passageway is closed by said ball only when said ball is engaging one of said seats, the plunger associated with said valve passageway being effective to move said ball against said second seat and to hold it there when an item is being placed against said associated cell area and then to release said ball for movement toward said first seat, said ball and valve passageway being proportioned and designed such that, if said cell area is not completely covered, the movement of air from said cell area through said valve passageway will move said ball into sealing engagement with said first seat and, if said cell is completely covered such that a vacuum is formed therein, said ball will stay between said seats to keep said cell area open to said vacuum pump.

17. The improvement of claim 16 including selectively variable orifice means for exhausting the compressed air from said passageways in said base plate to control the speed of movement of the plungers in releasing said balls for movement toward said first valve seats.

18. The improvement of claim 17 including spring means yieldably resisting the movement of said plungers by said diaphragm.

19. In a vacuum means for holding items comprising a vacuum source, at least one vacuum cell plate providing a front surface against which items are held, said cell plate providing a plurality of cell areas in said front surface, and conduit means for connecting said cell areas to said vacuum source, the improvement comprising, for each cell area, valve means effective to open said cell area to said vacuum source only when said cell area is completely covered by an item, each said valve means including means providing a valve passageway connecting the associated cell area to the vacuum source, said valve passageway providing a first valve seat therein facing the said cell area, a valve member movable against said first seat to close said valve passageway, thereby closing the associated cell area to said vacuum source, and actuating means for moving said valve member away from said first seat toward said cell area, holding it away from said first seat while an item is being placed against said front surface, and then releasing it for movement toward said first seat when the item is against said front surface, said'valve member and said passageway being proportioned and designed such that, if said cell area is not completely covered, the movement of air from said cell area'through said passageway will move said valve member into sealing engagement with said first seat and, if said cell area is completely covered such that a vacuum is formed therein, said valve member will not move against said first seat.

20. The improvement of claim 19 in which said passageway provides a second valve seat spaced apart from and facing said first valve seat, said member being movable between and sealably engageable with both of said valve seats, said actuating means being effective to move said valve member against said second seat and hold it there while an item is being places against said front surface and to release said valve member for movement toward said first valve seat when the item is against said front surface.

21. The improvement of claim 20 in which each actuating means includes an air actuated plunger for moving said valve member, a source of compressed air, and conduit means connecting said plungers to said source of compressed air.

22. The improvement of claim 21 in which said conduit means includes valve means for supplying air under pressure to said plungers and exhausting the air from said plungers, said conduit means including selectively variable orifice means through which the air under pressure is exhausted, whereby the speed of movement of said plungers in releasing said valve members is controlled.

23. The improvement of claim 21 in which said cell plate provides a back surface having a plurality of cavities therein in registry respectively with said cell areas, a rubber diaphragm covering said back surface and said cavities, said conduit means for the compressed air including a base plate having air passageways formed therein, portions of which overlie said cavities, whereby positive air pressure in said passageways deflects the portions of said diaphragm overlying said cavities, said plungers being movable by said deflecting diaphragm portions, and spring means for yieldably resisting movement of said plungers by said diaphragm portions.

24. The improvement of claim in which said means providing a valve passageway includes a cylindrical cell body threadedly engaged into said cell plate, said cell body having a coaxial threaded cylindrical bore therein providing said second valve seat, an orifice member threadedly engaging said bore and providing said first valve seat, said seats being frusto-conically shaped, said valve member being a ball, the diameter of which is less than the diameter of said bore.

25. The improvement of claim 24 in which each actuating means includes an air actuated plunger for moving said ball, a source of compressed air, and conduit means for connecting said plunger to said source of compressed air, said plunger extending through said orifice member to engage said ball.

26. The improvement of claim 25 in which said conduit means includes valve means for supplying air under pressure to said plungers and exhausting the air from said plungers, said conduit means including selectively variable orifice means through which the air under pressure is exhausted, whereby the speed of movement of said plungers in releasing said valve members is controlled.

27. The improvement of claim 25 in which said cell plate includes a rubber-like mat forming said front surface, said mat having openings therein defining said cell areas.

UNITED STATES PATENT OFFICE CEHFICATE ()F CORRECTION Patent Dated September 23, 1975 Inventor(s) Thomas H le It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 9, change "filling" to filing-.

Column 1, line 10, insert -Serial No. 456,054,

filed March 29, l974- before "disclosing".

Column 6, line 56, change "coverd" to -covered-.

Claim 20, line 7, change "places" to --placed gigned and gealed this eleventh D 3y Of May 1976 {SEAL} RUTH C. MASON C. MARSHALL DANN Armin-rig Officer (mnmisximur nflurcnls and Trademarks

Claims

5. The improvement of claim 4 in which each actuating means includes spring means for yieldably urging its associated plunger to its retracted, ball releasing position, the compressed air conduit means including valve means for supplying air under pressure to said plungers and exhausting the air from said plungers, and selectively variable orifice means through which the air under pressure is controlled and by which the speed of movement of the plungers in releasing the balls is controlled.

6. In a device for holding items comprising support means upon which items are held, the improvement comprising vacuum means for holding items to the support means, said vacuum means including a vacuum source, at least one vacuum cell plate mounted on said support means, said cell plate providing a front surface against which such items are held, said cell plate providing a plurality of cell areas in said front surface, sealing means extending about each cell area, and conduit means for connecting said cell areas to said vacuum source, said conduit means including, for each cell area, valve means, each said valve means including means providing a valve passageway having a first valve seat therein, and a valve member movable aGainst said first valve seat to close said passageway, thereby closing its associated cell area to said vacuum source, and actuating means for determining when its associated cell area is completely covered by an item and opening said cell area to said vacuum source only when it is completely covered by an item, said actuating means including means for holding said valve member away from said first valve seat and releasing said valve member for movement against said first valve seat when said cell area is not completely covered such that a vacuum can form therein, each actuating means including an air actuated plunger for moving said valve member, a source of compressed air, and conduit means connecting said plungers to said source of compressed air.

11. The improvement of claim 10 in which said valve means is proportioned such that its said valve member has a closing position in said passageway, said plunger being effective to move said valve member away from its closing position, to hold it away from its closing poSition while an item is being placed against the cell area, and to release said valve member for movement toward its closing position when the item is against the cell area.

19. In a vacuum means for holding items comprising a vacuum source, at least one vacuum cell plate providing a front surface against which items are held, said cell plate providing a plurality of cell areas in said front surface, and conduit means for connecting said cell areas to said vacuum source, the improvement comprising, for each cell area, valve means effective to open said cell area to said vacuum source only when said cell area is completely covered by an item, each said valve means including means providing a valve passageway connecting the associated cell area to the vacuum source, said valve passageway providing a first valve seat therein facing the said cell area, a valve member movable against said first seat to close said valve passageway, thereby closing the associated cell area to said vacuum source, and actuating means for moving said valve member away from said first seat toward said cell area, holding it away from said first seat while an item is being placed against said front surface, and then releasing it for movement toward said first seat when the item is against said front surface, said valve member and said passageway being proportioned and designed such that, if said cell area is not completely covered, the movement of air from said cell area through said passageway will move said valve member into sealing engagement with said first seat and, if said cell area is completely covered such that a vacuum is formed therein, said valve member will not move against said first seat.

24. The improvement of claim 20 in which said means providing a valve passageway includes a cylindrical cell body threadedly engaged into said cell plate, said cell body having a coaxial threaded cylindrical bore therein providing said second valve seat, an orifice member threadedly engaging said bore and providing said first valve seat, said seats being frusto-conically shaped, said valve member being a ball, the diameter of which is less than the diameter of said bore.