US3625559A

US3625559A - Lifting sling

Info

Publication number: US3625559A
Application number: US63364A
Authority: US
Inventors: Myrtle E Lawrence
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-08-13
Filing date: 1970-08-13
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07

Abstract

The sling comprises two end members of rigid material, such as steel, between which is connected an elongated strip of fabric, such as nylon webbing. The end members have openings though which the elongated strip is looped to connect the end members to the strip. A relatively short strip of the fabric material extends through the openings in each end member and is positioned between the elongated load-carrying strip and the end member. The short strips are clamped to the end members to keep them from shifting laterally with respect to the end member and bunching up at one side of the opening. The elongated load-carrying strip is stitched to the relatively short strips to thereby anchor it against a tendency for for such lateral movement and bunching up when under load.

Description

iinited States Patent [7 2] Inventor Myrtle E. Lawrence Houston, Tex.

[2i Appl. No. 63,364

[22] Filed Aug. 13, 1970 [45] Patented Dec. 7,1971

[73] Assignee The Lawrence M. Company Houston, Tex.

[54] LIFTING SLING 16 Claims, 8 Drawing Figs.

[52] US. Cl 294/74 [51] lnt.Cl B66c l/18 [50] Field of Search 294/67 E,

6/l966 France Primary Examiner-Even CL Blunk Assistant Examiner-i. Kenneth Silverman AnorneyHyer, Eickenroht, Thompson & Turner ABSTRACT: The sling comprises two end members of rigid material, such as steel, between which is connected an elongated strip of fabric, such as nylon webbing. The end members have openings though which the elongated strip is looped to connect the end members to the strip. A relatively short strip of the fabric material extends through the openings in each end member and is positioned between the elongated loadcarrying strip and the end member. The short strips are clamped to the end members to keep them from shifting laterally with respect to the end member and bunching up at one side of the opening. The elongated load-carrying strip is stitched to the relatively short strips to thereby anchor it against a tendency for for such lateral movement and bunching up when under load.

PATENTEU DEC 7 I97! SHEET 1 [IF 2 FIG. 2

Myrtle E. Lawrence IN VE N TOR ATTORNEYS PATENTEUBEB nan v 3,625.559

sum 2 BF 2" Myrtle E. Lawrence INVENTOR ATTORNEYS LIFT-INC SLING This invention relates to lifting slings generally and in particular to such slings that have a load-carrying member made of a fabric, such as nylon webbing.

Slings made of fabric, such as nylon and dacron webbing, are particularly advantageous for lifting material having surfaces or surface coatings that would be damaged if they were lifted with other means, such as wire cable slings. Fabric slings usually have end members that are attached at each end to an elongated strip of fabric by looping the fabric strip through openings in the end members and stitching the fabric together on each side of the end member. The end members, or end irons as they are often called because they are usually made of steel, have eyes or openings through which the lifting hook of a crane can be inserted to lift the sling and the load it supports. One problem with this type of sling is that when the load in the sling is off center or for some reason the force between the load-carrying fabric and the end iron is eccentric, the fabric, where it is looped through theopening in the end iron, will tend to move laterally relative to the end iron and bunch up in one corner of the opening in the end iron. This tends to accentuate the eccentric loading on the fabric material. Further, this lateral movement of the fabric on the end member will tend to abrade the fabric material and shorten its useful life.

It is an object of this invention to provide a lifting sling having an elongated load-carrying strip of fabric material that is held against lateral movement relative to the opening in the end member through which it is looped.

It is a further object of this invention to provide a sling having end irons of rigid material, such as steel, with openings through which an elongated strip of fabric material is looped wherein the fabric material is held against lateral movement relative to the end members and flat against the side of the openings to keep the fabric strip from tending to bunch up at one side or the other of the opening in the end members when subjected to eccentric loading.

These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the appended claims and attached drawings.

In the drawings: 7

FIG. I is a prospective view showing a sling of the type to which this invention relates lifting a joint of pipe;

FIG. 2 is a plan view of a sling, such as'the sling shown in FIG. I, constructed in accordance with the preferred embodiment of this invention;

FIG. 3 is a view of the sling of FIG. 2 taken along line 3-3 of FIG. 2;

FIG. 4 is a plan view of one end iron of an alternate embodiment of the sling of this invention with the fabric portion of the sling shown in section;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a partial view of the end member of FIG. 4 when the sling is subjected to a load;

FIG. 7 is a partial plan view of an end member of another embodiment of the invention; and

FIG. 8 is a sectional view taken along line 8-8 of FIG. 7.

Lifting slings of the type to which this invention relates can be connected to a load as shown in FIG. I. This is called a choker hitch." Alternatively, both end members, or end irons, can engage the hook on the crane or hoist. When the sling may be used to provide a choker hitch, the end members are shaped somewhat as shown inFIG. 2. Both are generally triangular in outward configuration. End member 10 has two

openings

12 and 13, whereas end member 11 has only one generally triangular opening 14. As will be explained in detail below, an elongated strip of fabric, such as nylon webbing, is looped through

openings

12 and 14, respectively, of end members l0 and II to connect the two together. When placing the sling around a load, end members 11 can be extended through opening 12 and then attached to the hook of the crane and a choker-type hitch, such as shown in FIG. I, is formed. If the sling is always to be used as a choker hitch type sling, then opening 13, and in fact the upper portion of end member 10, would not be required.

End members 10 and II are usually flame-cut out of steel plate. End member 11 has V-shaped portion 11a, the ends of which are connected to generally straight, parallel sides 11b and Ilc. Base 11d extends between sides Ilb and lie. The distance between

straight sides

11b and 11c is preferably just enough to allow the strips of fabric material making up the sling to be looped through opening 14 and lay flat against the inside straight surface of base 1 Id.

End member 10 is also generally triangular in shape. Side 12a of opening 12 should be only slightly wider than the strips of fabric making up the sling so that lateral sliding of the fabric on side 12a is held to a minimum. Opening 12, however, must be wide enough to pass end member ll. This is done by making it wider at the bottom than at the top. In other words, end member 10 has a generally V-shape portion with

legs

10a and 10b the ends of which are connected together by base member 10c. Sides 12b and of opening 12 are generally parallel to the sides of end iron 10 so that the opening across the base is large enough to pass end member 11 when the sling is used as a choker hitch. In view of this, however, side 12d is substantially wider than the fabric used on the sling. Therefore, base 100 is made wide enough to allow notch 15 to be cut therein to receive all the layers of fabric that will be looped through opening 12 in the manner to be described below.

As explained above, in slings of this type a load-carrying strip of fabric is connected to two end members. In accordance with the embodiment of the invention shown in FIGS. 2 and 3, first relatively short anchor strips 18a and [8b of flat-sided fabric material are looped through

openings

12 and 14 of end members 10 and II, respectively. Means are provided to anchor the first strips in the openings in the end members so that they will be held flat against the straight sides of base lld and notch 15 and against lateral movement so that they will not tend to bunch up at one side or the other of the openings in which they are located due to an eccentric load on the sling. In the embodiment shown, anchor bars 200 and 20b are positioned across

strips

18a and 18b parallel to the straight sides of bases 10c and Ild and bolted to the bases, as shown in FIG. 2. This clamps first strips and 18b to the end members to hold the strips flat and against any lateral shifting relative to the end members. Anchor bars 20a and 20b are made of a relatively rigid material, such as steel; therefore, to protect the load-carrying strip of fabric that is to be looped through the end members to complete the sling, second relatively

short strips

22a and 22b of fabric are looped through the openings in the end members to cover anchor bars 201: and 20b.

Next elongated load-carrying strip 24 is looped through both

openings

12 and 14 in

end members

10 and 11, respectively. This strip of fabric is double-backed upon itself and the overlapping portions are stitched together as shown at 26 in FIG. 3. Preferably, then all of the overlapping portions of the strips are extensively stitched to connect them all together into one composite elongated length of fabric extending between the end members. Since load-carrying strip 24 is attached to both first and second short strips 18 and 22, and since the first strip is held flat and anchored against lateral movement by anchor bars 200 and 20b, the load-carrying strip will be so anchored also. Thus, the strips of fabric will remain as shown in the drawings ven though the load the sling is carrying imposes an eccentric loading on the strips relative to the end members that would otherwise tend to cause the fabric to move laterally and bunch up.

Referring now to FIGS. 4, 5, and 6, an alternate embodi ment of this invention is shown. Only one end iron is illustrated in the drawings since the same general arrangement is used at the other end iron. In this embodiment, first relatively short anchor strip 30 is looped through opening 31 in end member 32. Slot 33, similar to slot 15, in end member 10, is provided to receive the strips of fabric. Anchor bar 34 extends across the top of first strip 30 and is attached, as by welding, to opposite sides of slot 33. Wear strip 35 and elongated loadcarrying strip 36 are then looped through opening 31 as shown in FIG. 4 and in the same manner as described in connection with the embodiment of FIGS. 2 and 3. In this embodiment, however, anchor bar 34 does not clamp first strip 30 against the bottom of slot 33 until a load is imposed on the sling. Then, as shown in F K}. 6, the load on the load-carrying strip will bend anchor bar 34 causing it to clamp first strip 30 between it and the bottom of slot 33 and effectively hold the first strip flat and against lateral movement relative to the end iron.

The embodiment shown in FIGS. 7 and 8 is similar to that just described. In this embodiment, however, anchor bar 40 is located in slots or

keyways

42 and 44, as best seen in FIG. 8, so that the bar will be forced against anchor strip 46 to hold it flat and to clamp the strip between it and the bottom of slot 48. Bar 40 will be moved down into this clamping and holding position whenever a load is imposed on the sling. The load is transferred to the anchor bar through load-carrying strip 50 and wear strip 52.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus and structure.

The invention having been described, what is claimed is:

l. A lifting sling comprising two end members of relatively rigid material each having an opening therein, a first strip of fabric extending through the opening in one of the end members, means anchoring the first strip to one side of the opening to hold the strip from moving laterally along the side, a loadcarrying strip of fabric extending through the opening and attached to the first strip to be held against lateral movement by the first strip and the anchoring means.

2. The sling of claim 1 in which the anchoring means comprises an anchor bar attached to the end member to clamp the first strip between the bar and the end member to hold the first strip from lateral movement.

3. The sling of claim 1 in which the anchoring means includes an anchor bar mounted on the end member and positioned between the first strip and the load-carrying strip and held against lateral movement by the end member to clamp the first strip between the bar and the end member when the load-carrying member is subjected to a load.

4. The sling of claim 3 in which the anchor has or bar is bent by the load-carrying strip when the load-carrying strip is subjected to a load to move the bar into clamping engagement with the first strip.

5. The sling of claim 1 further provided with a second strip of fabric material extending through the opening between the anchor means and the load-carrying strip to provide a wear strip between the anchoring means and the load-carrying strip.

6. A lifting sling comprising two end members of rigid material, such as steel, and an elongated load-carrying strip of flat-sided, flexible fabric material, such as nylon webbing, extending between and connected to the end members, at least one ofsaid end members having an opening through which the elongated strip extends, said opening having a generally straight side parallel to the flat sides of the strip, a relatively short strip of said flat-sided fabric material extending through the opening between the load-carrying strip and the end member and attached to the load-carrying strip with one side adjacent the straight side of the opening, and means for holding the short strip flat against the straight side of the opening and against lateral movement relative to the end member to in turn hold the load-carrying member flat and from such lateral movement.

7. The sling of claim 6 in which the holding means comprises an elongated bar attached to the end member to clamp the short strip of material to the end member and hold the strip flat against the straight side of the opening.

8. The sling of claim 6 further provided with a second relatively short strip of said fabric material extending through the opening of the end member between the first-mentioned relatively short strip and the load-carrying strip to provide a wear pad between the holding means and the load-carrying member.

9. The sling of claim 6 in which the holding means includes an anchor bar mounted on the end member and positioned between the first strip and the load carrying strip, said bar being held against lateral movement by the end member but movable toward the first strip to clamp the first strip between the bar and the end member when the load-carrying member is subjected to a load.

10. The sling of claim 6 in which the anchor bar is bent by the load-carrying strip into clamping engagement with the first strip when the load-carrying strip is subjected to a load.

11. A sling for pipe and the like comprising a pair of triangular-shaped end members of rigid material, such as steel, having an opening therein having a generally straight side, a pair of anchoring strips of flat-sided flexible woven material, such as nylon webbing, each strip being looped through the opening in one of the end members and in engagement with the straight side thereof, means anchoring said strip to said side of the opening to keep said strip flat against said side and from bunching up toward one end of the side, and a load-carrying strip of flexible woven material extending through each of said end members and looped over said first strip and said anchoring means, said load-carrying strip being attached to the anchoring strips adjacent the end members to be held against lateral movement along said side of the opening and against bunching up as the anchoring means holds the first strip against such lateral movement and bunching up.

12. The sling of claim ll in which the anchoring means comprises an anchor bar attached to the end member to clamp the first strip between the bar and the end member to hold the first strip flat and from lateral movement.

13. The sling of claim 12 further provided with a second strip of fabric material extending through the opening between the anchor means and the load-carrying strip to provide a wear strip between the anchoring means and the loadcarrying strip.

14. The sling of claim 11 in which the anchoring means includes an anchor bar mounted on each end member, each bar being positioned between the anchoring strip and the loadcarrying strip and held against lateral movement by the end member to clamp the anchoring strip between the bar and the end member when the load-carrying member is subjected to a load.

15. The sling of claim 14 in which the anchor bars are bent by the load-carrying strip when the load-carrying strip is subjected to a load to move the bars into clamping engagement with the anchor strips.

16. The sling of claim 11 in which the woven material is nylon webbing.

Claims

1. A lifting sling comprising two end members of relatively rigid material each having an opening therein, a first strip of fabric extending through the opening in one of the end members, means anchoring the first strip to one side of the opening to hold the strip from moving laterally along the side, a loadcarrying strip of fabric extending through the opening and attached to the first strip to be held against lateral movement by the first strip and the anchoring means.

6. A lifting sling comprising two end members of rigid material, such as steel, and an elongated load-carrying strip of flat-sided, flexible fabric material, such as nylon webbing, extending between and connected to the end members, at least one of said end members having an opening through which the elongated strip extends, said opening having a generally straight side parallel to the flat sides of the strip, a relatively short strip of said flat-sided fabric material extending through the opening between the load-carrying strip and the end member and attached to the load-carrying strip with one side adjacent the straight side of the opening, and means for holding the short strip flat against the straight side of the opening and against lateral movement relative to the end member to in turn hold the load-carrying member flat and from such lateral movement.

12. The sling of claim 11 in which the anchoring means comprises an anchor bar attached to the end member to clamp the first strip between the bar and the end member to hold the first strip flat and from lateral movement.

13. The sling of claim 12 further providEd with a second strip of fabric material extending through the opening between the anchor means and the load-carrying strip to provide a wear strip between the anchoring means and the load-carrying strip.

14. The sling of claim 11 in which the anchoring means includes an anchor bar mounted on each end member, each bar being positioned between the anchoring strip and the load-carrying strip and held against lateral movement by the end member to clamp the anchoring strip between the bar and the end member when the load-carrying member is subjected to a load.

16. The sling of claim 11 in which the woven material is nylon webbing.