Longitudinally Stiffened Flexible Lifter For Arcuate Objects

Abstract

A vacuum lifter is provided for arcuately shaped objects which includes a flexible sheet having opposed parallel surfaces. A supporting member is connected to one surface of the sheet and a resilient sealing gasket is connected to the opposing surface of the sheet about the periphery thereof. A source of vacuum is provided and the sheet has a port through which the vacuum source communicates. Stiffening means are connected to the flexible sheet to prevent bending of the sheet about a line extending at an angle transverse to the longitudinal extent of the plate. The lifter is secured to an arcuate object by placing the gasket against the outer surface of the object so that a partial vacuum is formed in the compartment formed between the outer surface of the object, the sheet and the gasket. The sheet accomodates a range of diameters of arcuate objects by bending around its longitudinal axis to conform to the diameter of the objects.

Description

This invention relates generally to vacuum lifters and more particularly to a flexible lifter which is longitudinally stiffened to enable its use for cylindrical or arcuate objects such as newsprint rolls.

One of the most difficult handling problems for stevedores in loading and unloading cargo ships, trailers and other formes of conveyance are newsprint rolls which are generally in a weight range of 1,000 pounds to 3,000 pounds and are cylindrically shaped having a diameter ranging from approximately 36 inches to 44 inches. At present, newsprint rolls are normally loaded and unloaded by use of fork lift trucks having clamping devices which embrace the newspaper roll and are then clamped tightly against the outer surface to frictionally engage the roll while lifting the roll and moving it from one place to another. In order to frictionally engage the newsprint roll the clamping surfaces are of necessity abrasive to permit slippage of the newsprint roll when the roll is lifted and lowered. The lifting and lowering stresses as well as the abrasive surface of the lifters often causes damage to the newsprint roll. In addition, unless the roll is standing on one of its planar edges, it is difficult for the clamping device to get underneath the roll in order to embrace and carry the roll.

It is therefore an object of the invention to overcome the aforementioned disadvantages of the prior lifting devices.

Another object of the invention is to provide a new and improved lifting attachment for use on fork lifting trucks which will enable newsprint rolls to be easily handled and which will withstand the operational shocks and prevent damage to the newsprint rolls.

Yet another object of the invention is to provide a new and improved lifting attachement for use on fork lift trucks which will facilitate the handling of newprint rolls whether the newsprint roll is standing on its planar or cylindrical surface.

Still another object of the invention is to provide a new and improved flexible lifter which is stiffened longitudinally to enable securement of the flexible lifter to the object to be lifted from a lateral disposition.

Still another object of the invention is to provide a new and improved flexible lifter attachment which can be utilized by fork lift trucks and other conveyance devices which are secured to an object from a lateral position.

These an other objects of the invention are achieved by providing a new and improved vacuum lifter for arcuately shaped objects which comprises a flexible sheet having opposed parallel surfaces.

The sheet has a supporting member connected to one surface of the sheet and a resilient gasket connected to the opposing surface of the sheet about its periphery thereof. A source of vacuum is provided which is connected through a port in the sheet. A stiffening means is provided which is connected to the flexible sheet to prevent bending of the sheet about a line extending at an angle transverse to the longitudinal extent of the sheet. The lifter is secured to an arcuate object by placing the gasket against the outer surface of the object so that a partial vacuum is formed in the compartment formed between the outer surface of the object, the sheet and the gasket. The sheet accomodates a range of diameters of arcuate objects by bending around the longitudinal axis to conform to the diameter of the object.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein;

FIG. 1 is a front elevational view facing the gasket side of the vacuum lifter;

FIG. 2 is a top plan view of the lifter;

FIG. 3 is a side elevational view of the lifter;

FIG. 4 is an enlarged sectional view taken along the line 4--4 in FIG. 1; and

FIG. 5 is an enlarged fragmentary sectional view taken along the line 5--5 in FIG. 1.

Referring now in greater detail to the various figures of the drawing wherein like reference numerals refer to like parts, a flexible vacuum lifter embodying the invention is shown generally at 20 in FIG. 1.

As seen therein, the flexible lifter 20 basically comprises a flexible sheet 22 having a pair of opposed parallel surfaces a sealing gasket 24, a supporting member 26 (FIG. 2) and longitudinal stiffening means comprising a plurality of narrow longitudinally extending plates 28 connected to the front surface of sheet 22 and similar plates 30 connected to the rear surface of the sheet 22.

The sealing gasket 24 is connected about the periphery of the front surface of the sheet 22 and is preferably comprised of a resilient deformable closed cell material such as neoprene. The flexible sheet 22 preferably comprises a thin sheet of polyurethane but may also be formed of other suitable high tensile strength flexible materials such as neoprene or metal.

The supporting member 26 as best seen in FIG. 4 basically comprises a cylindrically arcuate supporting plate 32, a pair of transversely extending lifting bars 34, which are suitably welded to the supporting plate 32, and a plurality of integrally formed planar ribs 36 which extend transversely to the plane of arcuate lifting plate 32 and lifting bars 34. A supporting bar 38 is interposed between the supporting plate 32 and the flexible sheet 22. A similar supporting bar 40 disposed adjacent the front surface of the flexible sheet aligned with the supporting bar 38 and centrally of the flexible sheet 22 is also provided. A plurality of suitable fastening elements 42 extend through the supporting plate 32, supporting bars 38, sheet 22 and bar 40 to secure a sheet to the supporting member 26.

As best seen in FIG. 1, the stiffening plates 28 extend longitudinally of the flexible lifter and are transversely spaced along the transverse extent of the front surface of the sheet 22. As best seen in FIG. 2, the longitudinally extending plates 30 extend parallel to and are aligned with corresponding plates 28 on the opposing surface of sheet 22. The plates 30 also extend longitudinally and parallel to a supporting bar 38.

As best seen in FIG. 5, each of the plates 28 includes a plurality of washers 44 which are spaced along the length of the plate 29. Each of the washers 44 are preferably welded to the plates 28 and are aligned with an opening through which a suitable threaded fastener 46 extends. A similar plurality of openings are provided in plate 30 which are aligned with plates 28 so that fastener 46 can be telescoped through the plate 28, the washer 44, the plate 30 and then suitable secured to a nut 48 on the opposite side of plate 30. The head of the fastener 46 is preferably countersunk so that the front surfaces of plates 28 are completely flush and do not provide an abrasive surface which can abut the newsprint rolls.

Referring to FIG. 2, it should be noted that supporting member 26 further includes a bridging plate 47 which is integrally connected between lifting bars 34 and is integrally welded to a collar 49 which is journalled over a lifting pin 50 of a fork lift truck (not shown).

The support mechanism for supporting the lifter 20 is shown in phantom in FIGS. 1 and 2. The supporting mechanism is preferably of the type that rotates 90.degree. about the horizontal axis extending longitudinally of the truck and centrally through the center of the support mechanism. The support mechanism of the truck may also rotate 360.degree. about the same axis.

As best seen in FIG. 4 a pair of L-shaped brackets 52 are secured to the rear of the support plate 32 preferably by welding. The brackets 52 are mounted adjacent a pair of longitudinally extending slots 54 which extend through the supporting plate 32. Both of the brackets 52 support a leaf spring 56 which extend through openings 54 and are secured to the brackets 52 by suitable fasteners 58. The leaf springs 56 act to urge the flexible lifter to its smallest diameter which is shown in phamtom at 20' in FIG. 2.

Referring to FIG. 4, it can be seen that plates 40, 38 and 32 as well as the sheet 22 includes an opening through which one leg of an L-shaped pipe 60 extends. Pipe 60 is connected to a suitable source of vacuum as indicated by arrow 62 in FIG. 4. The preferred source of vacuum is reservoir tank which is in turn connected to a suitable vacuum pump.

The plates 28 which act as stiffening members also act in combination with washers 44 to distribute the vacuum uniformly through the entire front surface area of the flexible lifter 20. That is, the washers 44 space the major portion of plates 28 from the front surface of sheet 22. Accordingly, as is indicated by arrows 64 in FIG. 4, air can readily pass beneath the plates 28 past the washers 44 even when the resilient gasket 24 is deformed so that the plates 28 rest against the outer surface of an object being lifted.

As best seen in FIG. 4, a suitable cylindrical object such as a newsprint roll 66 can be secured to the lifter 20 by disposing the gasket 24 against the outer periphery of the roll 66. Suitable valves are then opened to connect the port provided in the sheet 22 by pipe 60 to the source of vacuum and thereby cause a reduced pressure within the compartment formed between the outer surface of the roll 66, the gasket 24, and the front surface of sheet 22. Once the gasket 24 has been properly seated, a partial vacuum is formed very quickly within this compartment and thereby enables the flexible lifter to be so secured to the roll 66 as to easily enable the lifting of the newsprint roll 66.

As best seen in FIGS. 3 and 4, a limiting member 68 is provided on the leftmost (as seen in FIG. 4) stiffening plate 30 of the flexible lifter. The limiting member 68 basically comprises a pin 70 having a pair of transversely extending end pins 72 and 74 which are integrally secured at the ends of pin 70. Pin 70 is connected centrally of the end pins 72 and 74.

The end pin 74 is suitably journalled in a pair of annular collars 76 which are preferably welded to plate 30. Pin 70 extends through a slot 78 in the plate 32. The pin 70 is thus pivotable around an axis through pin 74 which is journalled in collars 76. The maximum separation of the plate 30 from plate 32 is limited by pin 72 which abuts the rear surface of plate 32 when plate 30 is moved with the flexible lifter 20 to the position shown in phantom at 20' in FIG. 2. The limiting member 68 is provided so that the flexible lifter 20 may be used not only as shown in FIGS. 1 through 5 where the longitudinal plates 28 and 30 extend vertically but also when the lift truck rotates the flexible lifter to a position where the longitudinal plates 28 and 30 extend horizontally.

When the plates 28 and 30 extend horizontally, the limiting member 68 is at the uppermost end of the flexible lifter and prevents the weight of plates 28 and 30 from causing the upper portion of the flexible sheet to be bent to a diameter which is too small to fit over a cylindrical object. That is, the weight of the plates could cause the flexible sheet to curl over which prevents the gasket from being properly seated without the limiting member 68.

As best seen in FIG. 1, the sealing gasket 24 has four enlarged portions 80, 82, 84 and 86. The portions 80, 82, 84 and 86 which extend outwardly of the periphery of the remaining portion of the gasket 24 are not adhesively secured to the front surface of the sheet 22 as is the remaining portion of the gasket. The enlarged portions 80, 82, 84 and 86 are provided where the vacuum lifter 20 can be rotated 360.degree. about an axis extending horizontally and transversely to the center plate 40. In most lift trucks where there is only 90.degree. of rotation, only two enlarged portions of the gasket need be provided. For example, in FIG. 1 only portions 84 and 86 would be required since these would be the portions of the gasket which are in the uppermost position when the flexible lifter is seated against the outer surface of an object to be lifted.

The enlarged portions of the gasket are therefore provided because as the arcuate object is picked up off the ground, the maximum unseating stress comes at the uppermost portion of the gasket and the extra portion of the gasket acts to prevent the unseating at its most vulnerable spot.

It can therefore be seen that a new and improved flexible lifter has been provided for lifting arcuate objects. The stiffening members comprised of plates 28 and 30 act to enable the flexible sheet 22 to be arcuately bent only about a longitudinally extending line. Similarly, the stiffening members prevent the bending of the flexible sheet about a line transverse to the longitudinal extent of the lifter.

In operation the flexible lifter 20 is used in combination with a truck having a supporting system which is capable of raising and lowering as well as rotating the flexible lifter 20. In its typical utilization the flexible lifter is urged laterally towards an object which is to be lifted and as soon as the gasket is substantially seated the source of vacuum is connected to the vacuum compartment formed between the gasket and the flexible sheet 22. As soon as the gasket is seated, the compartment is closed by the outermost surface of the object.

As set forth above, a newspaper roll may be attached to the flexible lifter when the roll is either in a vertical or horizontal position. When the roll is in a vertical position the flexible lifter is laterally moved to substantially the center of the roll and laterally engages the roll as set forth above.

Similarly, when the roll is on its side, the lifter 20 is rotated to a position 90.degree. from the position shown in FIG. 1 and is lowered so that the lifter plate 40 is substantially aligned with the center of the roll. The lifter 20 is moved laterally towards the roll and as soon as the gasket is substantially aligned with the roll the source of vacuum is connected to the compartment formed between the gasket 24, the outer surface of the roll and the front surface of sheet 22. As soon as the partial vacuum is formed in this compartment, the newspaper roll can be lifted and transported as desired. To remove the roll from the lifter, a suitable valve is opened to restore atmosphere pressure to the lifter compartment.

Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current or future knowledge, readily adapt the same for use under various conditions of service.

Claims

What is claimed as the invention is:

1. A vacuum lifter for arcuately shaped objects comprising a flexible sheet which is formed of a flexible material and has opposed parallel surfaces and a source of vacuum, said sheet having a port through which said vacuum source communicates, a supporting member connected to one surface of said sheet, a resilient sealing gasket connected to the opposing surface of said sheet about the periphery thereof, and stiffening means connected to said flexible sheet to prevent bending of said sheet about a line extending at an angle transverse to the longitudinal extent of said sheet, said stiffening means comprising a plurality of closely spaced longitudinally extending plates provided along the entire transverse extent of said flexible sheet, said lifter being secured to an arcuate object by placing said gasket against the outer surface of said object so that a partial vacuum is formed in the compartment formed between the outer surface of said object, said sheet and said gasket, said sheet accommodating a range of diameters of arcuate objects by bending around its longitudinal axis to conform to the diameter of said object.

2. The vacuum lifter of claim 1 wherein said closely spaced longitudinally extending plates are connected to the front and rear surfaces of the flexible sheet.

3. The vacuum lifter of claim 2 wherein the longitudinally extending plates connected to the side of said sheet that said gasket is connected each have spacing means connected between the plates and said sheet, said spacing means enabling a uniform distribution of the partial vacuum in the compartment formed between an object to be lifted, the gasket and said flexible sheet.

4. The vacuum lifter of claim 1 wherein said gasket includes an enlarged portion on one side of said lifter, said enlarged portion being provided on the uppermost edge of said lifter when said lifter engages an object to be lifted, said enlarged portion being integral with said gasket and movable with respect to said sheet so that said portion provides a fortified sealing area when said object is lifted.

5. A vacuum lifter for arcuately shaped objects comprising a flexible sheet having opposed parallel surfaces and a source of vacuum, said sheet having a port through which said vacuum source communicates, a supporting member connected to one surface of said sheet, a resilient sealing gasket connected to the opposing surface of said sheet about the periphery thereof, and stiffening means connected to said flexible sheet to prevent bending of said sheet about a line extending at an angle transverse to the longitudinal extent of said sheet, said lifter being secured to an arcuate object by placing said gasket against the outer surface of said object so that a partial vacuum is formed in the compartment formed between the outer surface of said object, said sheet and said gasket, said sheet accommodating a range of diameters of arcuate objects by bending around its longitudinal axis to conform to the diameter of said object, said supporting member including an arcuate plate which is connected centrally to said flexible sheet, said arcuate plate including means for urging the transverse ends of said lifter in an arcuate shape to facilitate seating of the gasket against an arcuate object.

6. The vacuum lifter of claim 5 wherein said means for urging includes a pair of leaf springs which extend through said arcuate plate and urge the outermost edges of said flexible sheet inwardly, said springs enabling said transverse ends of said lifter to be resiliently flexible when said edges engage an object to be lifted.

7. The vacuum lifter of claim 1 and further including limiting means provided on at least one of said transverse edges of said lifter, said limiting means acting to prevent more than a predetermined spacing between said flexible lifter and said support means.