US3108791A

US3108791A - Rotary air table

Info

Publication number: US3108791A
Application number: US857466A
Authority: US
Inventors: Michael P Budney; Henry S Budney; Thaddeus W Budney; Matthew F Saczawa
Original assignee: Atlantic Machine Tool Works Inc
Current assignee: Atlantic Machine Tool Works Inc
Priority date: 1959-12-04
Filing date: 1959-12-04
Publication date: 1963-10-29
Anticipated expiration: 1980-10-29

Description

Oct. 29, 1963 M. P. BUDNEY ETAL ROTARY AIR TABLE 2 Sheets-Sheet 1 Filed Dec. 4, 1959 INVENTORS 'AvA EEEA Vl NNNZ E DDDc N UUUA M BBBS T T RSWF. A MHTM United States Patent O 3,108,791 ROTARY AIR TABLE Michael P. Budney, Berlin, Henry S. Budney and Thaddeus W. Budney, Newington, and Matthew F. Saczawa, Wetherseld, Conn., assignors to Atlantic Machine Tool Works, Inc., Newington, Conn.

Filed Dec. 4, 1959, Ser. No. 857,466 6 Claims. (Cl. 269-20) This invention relates to machine tools and more particularly to supports on which heavy xtures are positioned for various cutting operations such as boring and machining.

In performing cutting operations on Various materials including heavy fixtures it is necessary that the same be supported in such manner that they may be shifted with reference to the cutting device in order that cutting operations may be performed at desired locations thereon.

Work tables with various types of anti-friction devices have been used heretofore. However, because of the great weight of certain fixtures, problems have arisen in connection with the accurate supporting of the same and the shifting thereof to various positions.

It has been proposed heretofore to employ a support in which a fluid such as air is used to provide a cushion by means of which friction may be substantially reduced and relative movement between portions of the support readily accomplished. However, the manufacture of such a fluid lift support or table has involved difficulties, particularly in the casting of the same with the required arrangement of the fluid passages.

Accordingly, it is an object of the present invention to provide a fluid lift type work support or table adapted for heavy fixtures and in which the fixtures may be shifted by rotary or translatory motion.

Another object is to provide a fluid lift work-support having improved means to secure the same in adjusted position.

A further object is to provide an improved method of manufacturing a fluid lift table more particularly of the rotary type.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a top plan view illustrating one embodiment of the invention;

FIG. 2, a section on the line 2 2 of FIG. 1;

FIG. 3, an enlarged detail section on the line 3-3 of FIG. 1;

FIG. 4, a section on the line 4 4 of FIG. 2; and

FIG. 5, a section on the line 5-5 of FIG. 2.

Briefly stated, the present invention is embodied in a rotary fluid lift table assembly having a generally cylindrical base with a central post on which a work support is mounted for rotary movement relative to the base. The base is provided with a series of radially extending interconnected passages in its upper portion and a second such series in its lower portion. Relatively small upwardly extending openings from the upper series of passages permit lluid pressure to be ydirected against the underside of the support in order to provide a cushion between the support and the base. Similarly, downwardly extending openings from the lower series of radial passages permit the application of fluid downwardly against the surface on which the assembly is resting in order that it may be moved, as for example, translationally. A locking device is embodied in the assembly for the purpose of holding the support in adjusted position on the base. The base is so constructed and arranged that the fluid passages may be formed by drilling subsequent to the casting of the table and their arrangement andthe i in the base.

3,198,791 Patented Oct. 29, 1963 ICC method of manufacture is an important feature of this invention.

With continued reference to the drawing, a base 10 is provided having a central column 11 on which a support or vtable 12 is mounted on anti-friction bearings 13.

The base 19 is provided with a plurality of lower radial passages 14 interconnected by transverse passages 15 Lto form a lower substantially co-planar network. As indicated in FIG. 5, certain of the passages 14 and 15 are provided with plugs 16 and 17, respectively, to prevent the escape of fluid. The passages 14 each have a plurality of downwardly directed relatively small openings or apertures 1S to permit fluid introduced under pressure into the network to escape therethrough in order to provide a cushion for supporting the base so that it can be moved relatively -frictionlessly over the bed 69. For the purpose of introducing fluid into the network one of the radial passages 14a has a lluid supply line 19 connected to the base by a fluid-tight connection 20.

The base is also provided with a plurality of upper radial passages 22 interconnected by transverse passages 23 to form an upper substantially co-planar network. As illustrated in FIG. 4, the outer ends of certain of the

passages

22 and 23 are provided with fluid-

tight plugs

24 and 25, respectively. Each of the passages 22 is provided with a series of upwardly directed relatively small openings or apertures 26 through which fluid under pressure escapes, when desired, to provide a cushion for supporting the table 12 to permit relatively frictionless rotary movement thereof.

In the manufacture of the base 1t) it is contemplated that the same will Vbe cast without the upper or lower series of

passages

22, 23 or 14,' 15, respectively, and that such passages may be drilled subsequent to casting of the base. In order that iluid pressure may be applied evenly to the under side of the base 10, each of the radially eX- teding passages is provided with a series of spaced openings 18, with correspondingly radially spaced openings being provided in the various passages.

In order to connect the radial passages 14, a series of non-radial passages 15 are provided. Each of these is drilled normal to the radial passage which it intersects and extends to each side thereof sufficiently to intersect a transversely extending passageway. The passages 15 may be drilled from one side as indicated or, in order to reduce the length of the drill required, particularly for the larger size tables, a passage may be drilled from both ends toward the middle, in which event an additional plug 17 will be required.

Thedescribed series of radial and non-radial passages forms a communicating network which may be supplied with .fluid under pressure for discharge through the ports In the illustrated network of passages fluid may be supplied to ports lying on inner, intermediate and outer concentric circles to provide a fluid cushion. Obviously, the ports may be located in different positions and .providedin such number as may be required for a particular item of equipment. In order that uid pressure may be applied evenly -to the upper side of the base an upper network of passagesZZ, 23 and upwardly directed openings or ports may be formed within the upper portion of the base in similar manner to that described for the lower network.

The base lil is provided with a projecting portion Sil having a cap i371 whichpmay be screwed or otherwise attached to the portion 3i). The portion 30 has a fluid interlockcomprisinga substantially vertical bore 32 within which is a hollow cylinder 33. A piston 34 is slideably disposed within such cylinder andis provided with a plunger 35 having a reduced portion 36 at its upper end with a pressure `indicator v37 thereon whereby `an operator is able to visually ascertainv the amount of pressure to which the upper network is subjected. The plunger 35 is slideably retained in alignment with the cylinder 33 by a bushing 38 mounted in the cap 31, the bushing providing a substantially air-tight tit with the plunger 35.

The piston 34 has a central opening 40 in its lower portion in which is received a pin 41 having an enlarged ange 42 received within a recess 43 in the portion 3h Vof the base to maintain such pin in ixed position. A compression spring 44 is disposed about the upper portion of the pin 41 and bears against the ange 42 at one end and against the inner end of the opening 4t) at its other end. Fluid under pressure is supplied to the upper portion of the cylinder through a line 45 connected to an inlet opening 46 in the portion 30 by a huid-tight connection 47. A discharge port 48 is provided in the lower portion of the projecting portion 36 in communication with the interior of the cylinder 33.

The piston 34 is normally biased upwardly by the spring 44 to a position in which its lower end is above the passages 22, thus connecting the upper network of passages through cylinder 33 to the discharge port 48. When it is desired to rotate the Work table 12, fluid under pressure is introduced through the supply line 45 into the opening 46. Such iluid presses downwardly against the upper surface of the piston 34 to force the piston downwardly and compress the spring 44 until the piston is forced below the upper portion of the passages 22 whereupon the fluid can be distributed throughout the upper network and discharged through the holes 26 to provide a cushion between the base 1? and the work table 12.

When the piston is in its normal upper position, the upper network of passages is in communication with the discharge port 4S through the cylinder 33. As the piston is forced downwardly by luid from the supply line, such piston is interposed between the upper network of passages and the discharge port to prevent the escape of iluid through such port before the fluid from the supply line is admitted to the upper network of passages. After the work support has been moved to its new positionthe supply of iluid is stopped and the spring 44 again raises the piston to its upper position and permits fluid trapped in the upper network to escape through the discharge port 48.

The base is provided with a central opening 50 and a counterbore 51 in which is received a central column or post 11. Such column has a lower ilange 52 within the counterbore S1 and secured to the base 10 by screws 53. The upper end of the central column 11 has a reduced portion 54 to which a collar 55 is attached by screws 56.

The work supporting table 12 has a central opening 60 with a counterbore 61 having a hardened bushing 62 which receives the column 11. Bushing 62 has an upper iiange 63 for mounting the lower race of the anti-friction ball bearing 13. The upper race of the bearing 13 engages the lower portion of the collar 55 to permit relative rotation between the Work table 12 and the base 10.

The work table 12 is desirably provided with a plurality of T slots 65 in which clamps may be mounted for holding the fixture to be machined.

In order to maintain the rotary air table assembly in iixed adjusted position, one or more clamps 66 are provided, each of which has a base 67 and an attaching screw 68 threadedly engaging the bed or supporting surface 69 of the machine. In order to shift base 10, the screw 68 must be loosened so that the base 10 can be moved, as, for example, by translation, when fluid under pressure is supplied through the line 19. Base 10 may be clamped in adjusted position by tightening the screw 68 so that clamp 66 engages the base 10.

In order to lock the work table 12 in adjusted position relative to the base, the table is provided with an annular groove 70 in which is disposed a conventional clamp 71. The clamp 71 is arranged to move vertically into and out of contact with the lower surface of groove 70 by an eccentric cam '72 and a shaft 73 mounted in the enlarged 4 portion 39 and such shaft 33 is adapted to be rotated by a handle 74 to raise and lower the clamp 71.

In the operation of the device, fluid under pressure may be introduced into the lower network of passages and discharged through the openings 18 to provide a relatively frictionless cushion on which the base may be moved. Similarly, iiuid under pressure may be introduced into the upper network of passages and discharged through the openings 26 to provide a cushion between the base and the work table whereby the work table may be rotated relative to the base.

It will be obvious to those skilled in the art that various ychanges may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is illustrated in the drawings and described in the specification, but only as indicated in the accompanying claims.

What is claimed is:

1. A rotary table unit for supporting a heavy article and adapted to be easily moved comprising a base, a central column xed to said base, a work table rotatably mounted on said central column, said base having a plurality of upper and lower radial passages, said upper radial passages being interconnected by a plurality of transverse co-planar passages to form an upper network, each of said upper radial passages having a series of small Y upwardly directed openings so that fluid under pressure may escape to support said work table from said base and support said table on a fluid cushion, said lower radial passages being interconnected by a plurality of transverse co-planar passages to form a lower network, each of said lower radial passages having a series of downwardly directed openings so that iluid under pressure may escape to provide a fluid cushion on a supporting surface for said base whereby said base may be rotated or moved over said supporting surface, means for introducing fluid under pressure into said upper and lower networks, and means for locking said base relative to said table in xed adjusted position.

2. The structure of claim l in which said upper and lower radial passages and said interconnecting passages are drilled and are provided with plugs at their open ends, closing such open ends to prevent the escape of lluid therethrough.

3. A work table for supporting .a heavy object in a selected position and permitting relatively frictionless movement to other selected positions, comprising a base having an upper surface, said base being adapted for mounting on La bed of a machine, a support mounted on said base and having a lower surface complementary yto the upper surface of said base, means -interengaging the base and the support and restricting the same to relative rotational motion therebetween, said base having a network of substantially co-planar communicating passages,

said network comprising a plurality of equidistantly spaced radial passages substantially parallel to the surface of the base and a plurality of non-radial passages interconnecting the radial passages, there being one non-radial passage transversely intersecting each radial pass-age, each of said non-radial passages intersecting its radial passage at the same radius `as the other non-radial passages, each of said non-radial passages extending from its radial passage at least suiliciently to intersect a non-radial passage on each side of its radial passage, and a plurality of upwardly directed discharge -openings extending from the radial V passages into communication with Ithe lower surface of charge from said common passage, said Imeans comprising -a cylindrical passage transversely intersecting said common passage, a piston Within s-aid cy-hnd-rical passage, said piston having -a head closely fitting said cylindrical passage and a stem of reduced diameter, said cylindrical passage having inlet and outlet ports located on opposite sides of its intersection with said common passage, means biasing said piston toward the inlet port and with its head past the opening of the common passage to thereby permit communication between said common passage, said cylindrical passage and said outlet port, the portion of said head adjacent to said stem providing aan abutment against which fluid pressure may bear to move said piston against Athe biasing means in order to move the head past the intersection with the common passage and thereby block communication thereof with said `outlet port and to permit `communica-tion thereof with said inlet port, said stem having indicator means extending outwardly of said base to indicate the position of said piston within said cylindrical passage.

6. A structure for supporting work for adjustable positioning lof the work comprising a base for positioning `on a supporting surface, said base being provided with a lil-st set of fluid passages therein having orilices opening tively apply fluid pressure to each set `of uid passages so that when pressure is applied to said first set of iiuid passages the entire structure may be moved ovei said supporting surface Without external lifting force applying equipment, and when pressure is applied to said second set of iuid passages said support for the Work Imay be adjusted relative to the base to accurately position the Work relative to said base to provide for accurate positioning and locati-on of the work on the shaping machine Without requiring external lifting equipment.

References Cited in the lile of this patent UNITEDSTATES PATENTS 1,848,294 Howie Mar. 8, 1932 2,483,811 Cullen Oct. 4, 1949 2,746,143 Maine May 22, 1956 2,773,725 Roberts Dec. 11, 1956 2,787,175 Schurger Apr. 2, 1957 2,829,566 Geeks et al Apr. 8, 1958 2,859,667 Teubner Nov, 11, 1958 2,877,538 Conlon Mar. 17, 1959 2,885,915 Schurger May 12, 1959 2,900,849 Huto'hens et al Aug. 25, 1959 FOREIGN PATENTS 672,413 Great Britain May 21, 1952

Claims

1. A ROTARY TABLE UNIT FOR SUPPORTING A HEAVY ARTICLE AND ADAPTED TO BE EASILY MOVED COMPRISING A BASE, A CENTRAL COLUMN FIXED TO SAID BASE, A WORK TABLE ROTATABLY MOUNTED ON SAID CENTRAL COLUMN, SAID BASE HAVING A PLURALITY OF UPPER AND LOWER RADIAL PASSAGES, SAID UPPER RADIAL PASSAGES BEING INTERCONNECTED BY A PLURALITY OF TRANSVERSE CO-PLANAR PASSAGES TO FORM AN UPPER NETWORK, EACH OF SAID UPPER RADIAL PASSAGES HAVING A SERIES OF SMALL UPWARDLY DIRECTED OPENINGS SO THAT FLUID UNDER PRESSURE MAY ESCAPE TO SUPPORT SAID WORK TABLE FROM SAID BASE AND SUPPORT SAID TABLE ON A FLUID CUSHION, SAID LOWER RADIAL PASSAGES BEING INTERCONNECTED BY A PLURALITY OF TRANSVERSE CO-PLANAR PASSAGES TO FORM A LOWER NETWORK, EACH OF SAID LOWER RADIAL PASSAGES HAVING A SERIES OF DOWNWARDLY DIRECTED OPENINGS SO THAT FLUID UNDER PRESSURE MAY ESCAPE TO PROVIDE A FLUID CUSHION ON A SUPPORTING SURFACE FOR