US3227481A

US3227481A - Vacuum lifter

Info

Publication number: US3227481A
Application number: US257036A
Authority: US
Inventors: Jacob J Creskoff
Original assignee: Vacuum Concrete Corp of America
Current assignee: Vacuum Concrete Corp of America
Priority date: 1963-02-07
Filing date: 1963-02-07
Publication date: 1966-01-04
Anticipated expiration: 1983-01-04

Description

Jan. 4, 1966 J. J. CRESKOFF VACUUM LIFTER Filed Feb. 7, 1965 A W F INVENTOR. JACOB J. CRESKOFF ATTORNEY United States Patent This invention relates to a vacuum lifter particularly intended for the handling of loads having convex surfaces.

One of the many uses for which the lifter of thepresent invention is eminently suited is the handling of large rolls of paper of the types employed in the publications industries. Whereas suchpaper rolls are produced in a large variety of sizes, a great proportion of them have diameters ranging from thirty inches to. forty-two inches. Whereas the handling of such rolls by means of vacuum lifters has been proposed by the present applicant in the past, the diameter variation has always, presented a serious problem, since known lifters will not accommodate 3 such a range of sizes.

In accordance with the present invention, lifter has been developed which will be universally applicable to loads having concave surfaces of widely varyingforms and dimensions, including cylindrical and conical surfaces.

It is among the objects of the present invention to provide a vacuum lifter comprising a self-supporting frame having a first concave surface and a surface opposed thereto, a first deformable resilient gasket secured to the first surface having proximate edges defining a narrow open inner chamber with the frame, means defining a port for connecting the inner chamber with a source of reduced pressure, a second deformable resilient gasket secured to the first surface surrounding the first gasket defining an open chamber with the frame and first gasket, and means for connecting the outer chamber with a source of reduced pressure, the concave surface having a maximum radius between five and twenty times the distance between the proximate edges of the first gasket.

A preferred form of the invention provides a distance between the proximate edges of between one and five inches, a highly satisfactory lifter having been developed wherein the distance between the proximate edges of the first gasketis of the order of three inches. The gaskets are preferably compressible, and the inner gasket may be more highly compressible than the outer one, and they may be composed of a cellular elastomer.

The frame may be resilient and flexible and the inner and outer chambers are preferably interconnected by one or more passages having an aggregate cross-sectional area less than that of the port.

A more complete understanding of the invention will follow from a description of the accompanying drawings wherein:

FIG. 1 is a somewhat diagrammatic representation in elevation of a lifter applied to a load and connected with a vacuum pump through a reservoir;

FIG. 2 is a perspective view of a lifter conforming to the present invention;

FIG. 3 is a bottom plan view of a lifter embodying the invention; and

FIG. 4 is a sectional elevation taken along line 44 of FIG. 3 depicting the lifter in engagement with a load.

A lifter illustrated in the drawings comprises a frame or plate 12 to one surface of which are secured by means of adhesive, or in other suitable fashion, an inner gasket 14 and an outer gasket 16. Referring to FIG. 3 it will be observed that the inner gasket 14 defines with the frame or plate 12 an open chamber 18 containing a port 20 for communication with a source of reduced pressure through 3,227,481 Patented Jan. 4, 1966 1 a port 32 for the purpose of admitting atmosphere to the port 20 by proper manipulation of the valve handle 34.

The outer gasket 16 defines a chamber 36 with the frame or plate 12 and the inner gasket 14. The inner chamber 18 is connected with the outer chamber 36 by passage means, which may assume the form of small diameter tubes 38, extending through the inner gasket 14 and having an aggregate cross-sectional area less than the cross-sectional area of the port 20 through which the inner chamber 18 communicates with the vacuum pump As will be observed from the drawings, the frame or plate 12 has a concave surface receiving the gaskets and this surface is of substantially cylindrical form having a diameter approximating that of the largest cylindrical surface encountered in connection with loads to be handled. By having the inner gasket 14 more deformable or comsurfaces 'of smaller diameters. Similarly, by using'a frame or plate 12 which is resilient and somewhat flexible, the lifter can also adapt itself readily to loads having smaller diameters.

Theouter surface 40 of the frame or plate opposedto that hearing the gaskets is provided with a pair of lugs 42 containing openings for the reception of hooks or cables 44 for cooperation with a crane or other lifting devices for elevating the lifter together with its load 46.

In order to render lifters according to the present invention effective, it has been found that the cylindrical, conical or other concave surfaces 48 should have radii of between five and twenty times the distance between the proximate linear edges 50 of the gasket 14. The distance between these proximate edges will preferably lie between one and five inches and a distance of three inches has produced highly satisfactory results. The gaskets are preferably compressible and composed of a cellular elastomer. The ratio of the area of the port 20 to the aggregate area of the fluid passage means between the inner and outer chambers may be between 1.1:1 and 96.0:1, a preferred range of ratios lying between 25.0:1 and 50.0:1, a ratio of 36.0:1 having been found to be highly satisfactory in conjunction with a particular lifter which has been tested over a substantial period of time. In this particular lifter, the volume of the chamber defined by the inner gasket and, plate is of the orderof 0.28 cubic feet and the volume contained within the outer gasket is of the order of 1.18 cubic feet. For this lifter, a vacuum pump having a capacity of one-third horsepower is employed and the diameter of port 20 is one and one-half inches. Each of the four tubes 34 shown as providing communication between the inner and outer chambers has an inside diameter of one-eighth inch. With this equipment, a vacuum corresponding to twenty inches of mercury is established within a few seconds in both the inner and outer chambers when the valve is adjusted to provide communication between the vacuum pump and the port 20, with the lifter in engagement with a load. To release the lifter from the load, the valve is adjusted to admit atmospheric pressure through the port 32 and the hose 24 to the port 20.

By providing an inner gasket 14 of higher compressibility than the outer gasket 16, the flexibility of the frame can be reduced or eliminated without sacrificing the universal application of the lifter to loads having curvilinear surfaces ranging over widely varying radii.

The ratio of the area within the second gasket to the barea, within the first gasket may be between 2.5 :1 and .1 6.0: La preferred-range-being-between 4.0: 1 and 13.0: 1, the particular lifter described above providing a ratio of 50:1 in this regard.

=When the-lifter is applied to a load having substantially the maximum diameter for whichthe lifter is. intended, I, Whenthe proximate linear edges 50 of the innerngasket- 14 engage the surface of theload, the valve..26 will be operated to connect the-inner chamber 182Witl1 the reservoir:28 and vacuum pump-30 so that the air .within this v.inner chamber will be quickly evacuatedthrough the relatively large port 20. As result of this evacuation f .the inner chamber, the inner gasket 14 will become deformed or compressed bringing the concave surface of -the frame closerto the-load so that a seal will be effected between the outer gasket 16 and .the load 46. Continued application ofthe reduced pressure Will remove the air .fromthe outer chamber 36 through the passages 38 so that the outer chamber will also be evacuated relatively quickly placing the lifter and load in their operating relationship whereby thelifterand load can be moved to a .desired position. When the valve 26 is manipulated to .admit atmospheric pressure through the port 32 and the port 20, the lifter will quickly release the load.

.It .Will be observed that if the inner gasket 14 is more highly compressible than the outer gasket'16, the lifter .will adapt itself to loads having surfaces of substantially smaller diameters than the largest diameter for which the lifter is designed. Similarly, Where the frame or plate 12 .is somewhat resilient and flexible; the device will also readily adapt itself to rolls or other substantially cylindri- .cal .loads having .diameters less .than the maximum I diameter for which the device was designed.

Whereas only one example of the invention has been described with reference to the drawings, such variations as will occur to those skilled in the art are contemplated as coming within the scope of the appended claim.

I claim:

A vacuum lifter comprising a self-supporting frame having aconcave surface and a. surface opposed thereto, a first deformable resilient gasket secured tosaid. concave surface having proximate edges-defining a narrow open inner chamber with said frame,-means defining a port for connecting said inner chamber with a source of reduced pressure, a second deformable resilient gasket secured to said concave surface surrounding said first gasket defining an open outer chamber with said frame and first gasket, and means for connecting saidouter chamber with a source of reduced pressure,-said concave surface-having a maixrnum radius between five and tWenty-timesthe distance between said proximate edges, said'inner gasket being more highly compressible than. said outer gasket.

References Cited by the Examiner V UNITED STATES PATENTS 3,055,694 t 9/1962 Billner 294- 3,063,746 11/1962 Oakes 294-64 3,089,723 5/1963 Fortson et al 29465 3,117,815 1/ 1964 Creskoir 294-64 GERALD 'M. FOR-LENZA, Primary Examiner.

' ERNEST A. FALLER, SAMUEL F. COLEMAN,

Examiners.

G. F. ABRAHAM, Assistant'E-xaminer.