US3779593A

US3779593A - Open-mesh support grip construction

Info

Publication number: US3779593A
Application number: US00250330A
Authority: US
Inventors: D Neuroth
Original assignee: Harvey Hubbell Inc
Current assignee: Hubbell Inc
Priority date: 1972-05-04
Filing date: 1972-05-04
Publication date: 1973-12-18
Anticipated expiration: 1990-12-18

Abstract

The construction involves a device that is assembled on a conventional wire cable grip to improve the latters'' gripping action. The device comprises an elongated rod provided intermediate its length with an adjustable spring seat. A helical compression spring has one end in engagement with the seat and extends in coiled relation around the rod toward one end of the rod. Suitable means connect the other end of the spring to the draft end of the grip and suitable means connect the other end of the rod to the object receiving end of the grip.

Description

United States-Patent 1191 [111 3,779,593 ur Dec. 18, 1973 [54] OPEN-MESH SUPPORT GRIP 2,688,172 9/1954 Kellems 24/123 F CONSTRUCTION 2,844,843 7/1958 Logan 24/l23 F X [75] Inventor: David H. Neuroth, New Haven, Primary Examiner Ev0n C Blunk Conn Assistant Examiner.lohnny D. Cherry [73] Assignee: Harvey Hubell Incorporated, y- Hart at Bridgeport, Conn. 22 Filed: May 4, 1972 [57] ABSTRACT The construction involves a device that is assembled 1 Appl' on a conventional wire cable grip to improve the latters gripping action. The device comprises an elon- 521 U.S. Cl. 294/86 cc, 24/123 F gated rod provided intermediate its length with an [51] Int. Cl. Fl6g 11/03 justable Spring 5631- A helical compression Spring has 58 Field of Search 294/86 R, 86 co; one end in engagement with the seat and extends in 24/123 F coiled relation around the rod toward one end of the rod. Suitable means connect the other end of the [56] References Ci d spring to the draft end of the grip and suitable means UNITED STATES PATENTS connect the other end of the rod to the object receiving end of the grip. 2,268,598 1/1942 Kellems 294/86 CG 2,318,164 5/1943 Kellems 294/86 CO 14 Claims, 7 Drawing Figures PATENIEDHEC 18 I915 FIG.

FIG. 6

FIG. 2- FIG. 4

OPEN-MESH SUPPORT GRIP CONSTRUCTION THE INVENTION This invention relates to braided, open-mesh support grips in which strands of wire or other suitable material are woven in tubular form to permit lateral expansion through endwise compression, or lateral compression through endwise extension, so that when compressed endwise the woven grip may be readily placed over and upon a cable or other object, or the object may be drawn freely endwise therethrough from the receiving end toward the draft end, and when the endwise compression is relieved the device will automatically grip the surface of the object. When the object is supported by the grip, the weight of the object will exercise a further stress on the grip such as to cause it to increase its gripping action on the object.

It is known that most grips of the conventionally woven wire mesh type squeeze an object a certain amount for a given load imparted to the grip by the object being supported thereby. Because of this fixed relationship between the amount of squeeze generated by a grip of standard design for a given pull on the grip, the grip may not be successfully used in certain situations. Thus, it has been found that if there is present a very low coefficient of friction between the grip and the surface of the object to be held, or if there exists a slippery interface between one or more layers within the held object, there may not be sufficient squeeze generated by the grip to support the object properly. A condition of this nature often exists with electrical power cables having various layers of insulation and shielding, with exterior surfaces that are so smooth, hard and slick that the gripping ability of standard design grips thereon are substantially reduced. Where the coefficients of friction between certain of these layers in the cables are sufficiently low, the transfer of the holding forces generated by the grip to the inner regions of such cables may not be sufficiently adequate. In an effort to overcome this problem, the art has devised specially designed gripping devices.

It is the principal purpose of this invention to provide a device which can improve the effective gripping action of existing commercially available wire mesh support grips of conventional constructions.

Another object of the invention is to provide such a device constructed to enable it to be readily installed on a conventional grip without any modification of the grip, or the manner in which the grip is attached to the support structure with which it is used in supporting the object.

A further object of the invention is to provide a simple, inexpensive device which can be rapidly installed in the field, and which will add a significant factor of safety to existing support systems.

,Other objects of the invention, as well as the advantages and novel features thereof will appear from a consideration of the following description when read in connection with the accompanying drawgins, in which FIG. 1 is a perspective elevational view showing a conventional wire grip mounted on a cable and provided with a device embodying the invention;

FIG. 2 is a front elevational view of the device per se;

FIG. 3 is a side elevational view of the device and showing the manner in which it is connected at its upper end to the grip of FIG. 1;

FIG. 4 is an enlarged, partial front view showing in greater detail the manner in which the device is connected to the grip part shown in FIG. 3;

FIG. 5 is an elevational-view of the top portion of another grip of conventional design and illustrates how a modified form of the device may be connected under the draft portion of the upper part of the grip;

FIG. 6 is an elevational view of the bottom portion of another grip of conventional design and illustrates another form of the device connected to the object receiving end of the grip; and

FIG. 7 is a view similar to FIG. 6 and shows a further modification of the device and a method of connecting the same to the object receiving end of the grip.

Referring now more particularly to FIGS. 1-4 of the drawings, the numeral 10 generally designates a cable to be supported by a wire mesh grip generally designated 11. The grip shown in FIG. 1 is of the type shown in the Kellems U.S. Pat. No. 2,688,172 dated Sept. 7, 1954, but it will be understood that the invention may be used to equal advantage with any wire mesh grip of conventional design as will later become more apparent. In all of these conventionally designed grips, the strands forming the gripping device per se, which may be woven in the form of a complete tube, or as a split tube, are braided so that the crossing portions of the strands are relatively movable to' permit free radial expansion through endwise compression in their tubular form and also to cause radial compression of the strands upon the supported object through endwise extension of the tube. The braided body portions of these grips are usually made so that in their tubular form they will have a nominal internal diameter smaller than the external diameters of the range of cables or other objects for which they have been designed. When mounting a tubularly woven grip on an object, it is usually expanded radially by endwise compression to enable it to receive the object, and when the compression force is removed, the grip contracts radially to frictionally engage the periphery of the object. Split grips are usually mounted on the object and then secured in tubular form thereon. The body portions of these conventional grips are usually provided at one end with one of the many types of draft devices available to the art for enabling the grip to support or draw an object, and when such draft device is connected to support means, such as a hook, the weight of the object will cause the grip to effect a firmer grip thereon. Any subsequently applied forces tending to slide the grip from the object gripped thereby will tend to cause the grip to grip the object more firmly. It has been found however, that when the object is subjected to alternate loading and unloading forces there is a tendency of the conventional grip to slip along the object. This is especially true when as in present day cables, the surface of the object has a smooth, hard surface.

The grip shown in FIG. 1 of the drawings is of a type frequently used in the permanent overhead installations of telephone and electric lighting cables. In the formation of this grip the strands of the grip body 12 are extended beyond the draft end thereof and divided into two double diametrically disposed groups or

branches

13,13 each one of the groups containing a like number of strands twisted into rope form. The outer ends of each pair of branches are connected together by an arcuately shaped metal tube 14 to form an open shaped loop or eye. Adjacent to the roots of each pair of

branches

13,13 is provided a longitudinally extending metal tube into which the strands of the grip body are gathered to form the branches 13. As is shown more clearly in FIG. 4 of the drawings, because of the progressive gathering of the strands in the tubes 15, there is in the lower portion of each tube 15 a centralized, longitudinally extending space 16 which enables one of the tubes 15 to also serve as a latch member for securing the upper portion of the device of this invention to the grip 11.

The device of this invention comprises a rod 20, the dimensions of which may depend on the range of sizes of the grips on which it is to be used. Thus, as is indicated in FIG. 1, the length of the rod may approximate the length of the body 12 of the grip. The rod is made rigid enough to enable it to withstand the compressive stresses to be applied thereto without collapsing. To this end it has been found that a ,4; inch diameter rod is adequate for most types of installations. Connected to the bottom end of the rod 20, as by a weld, is a pronged member 21 formed of a piece of wire bent into U-shaped form. As is shown more clearly in FIG. 3, the two prongs of member 21 are inclined downwardly and outwardly at an angle of approximately 15 with relation to the longitudinal axis of the rod 20. This construction enables the prongs of member 21 to be readily inserted into the loops 22 formed at the bottom of the grip as above in FIG. 1, or into two adjacent lateral mesh 23 formed by the grip weave, and to be locked in such engaged relation on the grip when the rod is moved toward the grip to a position parallel to the longitudinal axis of the latter as is shown in FIG. 1.

Intermediate the length of the rod 20 is provided a spring seat 24 formed by forcing a one way washer onto the rod so that the cut teeth bite into the material of the rod below the washer. Mounted on the rod 20 and seated at its lower end on the seat 24 is a helicallyshaped compression spring 25. The upper end of the spring 25 is formed to provide an upwardly or outwardly extending end piece 26 that is spaced from and parallel to the longitudinal axes of the rod 20 and spring 25. The end piece 26 is spaced sufficiently from the rod 24 to enable it to be inserted up into the space 16 provided in the metal tube 15 forming part of the grip. This assembly operation is accomplished in the field by the worker using a modified pair of pliers capable of compressing the spring by moving the one way washer 24 up on the rod 20.

It will be understood from the foregoing, that when the device of this invention is installed on a grip, the compressive force of the spring will be exercised on the spaced parts of the grip to which the device is attached i.e., the tube 15 with which the end place of the spring is latched, and the end loops 22 with which the prongs of member 21 are interlocked. This compressive force of the spring tends to elongate the body 12 of the grip thereby causing it to radially contract on and to grip the object. This compression action of the strands on the object under the force provided by the spring is substantially greater than what the grip per se is capable of normally exercising when it is released after being inserted on the object. This increased compressive action will be further supplemented when the object becomes fully supported by the grip in the same manner that the hold of the grip would be increased without the use of the device of this invention. However, the total resulting gripping force exercised on the supported object by the combined grip and device will be sufficiently greater than that capable of being exercised thereon by the grip per se, that many objects which have heretofore been unsupportable by conventional wire mesh grips alone, can now be successfully and reliably supported by the combination. It will be noted also that as soon as the device of the invention is assembled on a grip, the grip is caused to exercise a squeezing action on the object and will firmly grip the same even before the object is mounted in its supported condition through the grip. This reduces the tendency of the grip to slip along the object as it is being subjected to the varying forces normally encountered due to movements during installation or due to thermal expansion and contraction of the cable with temperature changes.

It is within the contemplation of this invention to secure the upper end of the device of this invention to the draft end of a grip by inserting the end piece 26 of the spring 25 through a mesh of the grip body in the manner of the prongs of member 21 in the event that grip is not provided with the aforesaid tubes 15. It is preferred that when the device is so connected that the end piece 26 be inserted under a strand crossing. FIG. 5 of the drawings, illustrates another method of assembling the device on a conventional grip not provided with the tubes 15 in the grip shown in FIG. 1. In the grip of FIG. 5, the strands forming the grip body 12' are at the draft end of the grip gathered into two groups or branches 13' which are connected together by a metal tube 14 to form a single draft loop which will be located to one side of an object, such as the cable 10, supported by the grip. In the embodiment of the invention shown in this figure the outwardly extending end piece 26 of the spring 25 has been dispensed with and in its place there has been substituted a separate suitable mesh engaging element such as the formed wire hook 26 illustrated. The mesh engaging element 26' is provided with a looped end 27 which is slidably mounted on the upper end of the rod 20 and seated against the upper end of the spring 25 which is preferably square ended. After its assembly on the rod 20, the hook 26 is engaged under the wire mesh of the grip body and preferably so that it engages the wires forming the base of one end of the draft loop. It will be understood that the other end of the device may be mounted on the grip in the manner previously described with relation to the grip shown in FIG. 1.

In the embodiment shown in FIG. 6 of the drawings, a preformed wire hook 21' is also employed to connect the lower end of the rod 20 to the mesh at the object receiving end 29 of a conventional grip. In this form of the invention, the lower end of the rod 20 is provided with a suitable opening 29 which may be in the form of a hole or slot to connect the hook 21' to such rod. Instead of a preformed wire hook, there may be employed wire lacing 21" to secure the lower end of the rod 20 to the object receiving end of the grip as is shown in FIG. 7.

What is claimed is:

l. A separate, unitary device attachable to a conventional expansible and contractible unit having an openmesh body and an object-receiving end and a draft end in order to increase the gripping power of such openmesh body on an object, said device comprising an elongated member, first means provided on said elongated member intermediate the ends thereof and operable as a stop in one direction, second means for connecting a part of said elongated member located in spaced relation to one side of said first means, in fixed relation with the strands forming the mesh at one part of said open-mesh body, compressible means located on the other side of said first means and seated against said first means, and third means located on the other side of said first means in spaced relation thereto, said third means being connected to said compressible means, being movable relative to said elongated member, and connectible in fixed relation to another part of said open-mesh body longitudinally spaced from said one part thereof.

2. A device as defined in claim 1, in which said elongated member is a rod and in which said first means is movable in the other direction to compress said compressible means.

3. A device such as defined in claim 2, in which said first means comprises an annular member and means cooperable with said rod to limit movement of said annular member toward said second means and to permit selective movement of said annular member in the direction of said third means.

4. A device as defined in claim 1, in which said elongated member is a rod, and in which said second means connects one end of said rod to said one end of said open-mesh body.

5. A device such as defined in claim 4, in which said second means comprises a member connected to said one end of said rod and having two outwardly projecting prongs.

6. A device such as defined in claim 5, in which said prongs are inclined outwardly at an angle with relation to the longitudinal center of said rod.

7. A device as defined in claim 4, in which said second means comprises means interengageable with the mesh of said open-mesh body, and means connecting said interengageable means to said one end of said rod.

8. A device as defined in claim 1, in which said compressible means comprises a helical compression spring having one end engaging said first means and extending in coiled relation around said elongated member, said third means being connected to the other end of said spring. I

9. A device such as defined in claim 8, in which said third means comprises a straight end portion of said spring extending outwardly from the helical body thereof in substantially parallel relation to and spaced from the longitudinal center of said spring.

10. A device as defined in claim 1, in which said third means comprises means interengageable with said other part of said open-mesh body, and means connecting said interengageable means to said compressible means.

11. A device as defined in claim 10, in which said interengageable means is constructed to interengage the mesh of said open-mesh body.

12. A device as defined in claim 10, in which said connecting means is slidably mounted on said elongated member and is in engagement with the outer end of said compressible means.

13. The combination of an expansible and contractable unit composed of a plurality of strands arranged about a common axis to form a tubular structure adapted to receive an object to be held, and a separate, unitary device attached in fixed relation to spaced parts of said tubular structure, said unitary device comprising an elongated member extending longitudinally, exteriorly of said structure, first means provided on said elongated member intermediate the ends thereof and operable as a stop in one direction, second means for connecting a part of said elongated member located in spaced relation to one side of said first means, in fixed relation with the strands forming the mesh at one part of said open-mesh body, compressible means located on the other side of said first means and seated against said first means, and third means located on the other side of said first means in spaced relation thereto, said third means being connected to said compressible means, being movable relative to said elongated member, and connectable in fixed relation to another part of said open-mesh body longitudinally spaced from said one part thereof.

14. The combination defined in claim 13, in which said compressible means comprises a helical compression spring having one end engaging said first means and extending in coiled relation around said elongated member, said third means being connected to the other end of said spring, and said first means being movable on said elongated member in a direction to compress said spring and capable of maintaining said spring in compressed condition.

Claims

1. A separate, unitary device attachable to a conventional expansible and contractible unit having an open-mesh body and an object-receiving end and a draft end in order to increase the gripping power of such open-mesh body on an object, said device comprising an elongated member, first means provided on said elongated member intermediate the ends thereof and operable as a stop in one direction, second means for connecting a part of said elongated member located in spaced relation to one side of said first means, in fixed relation with the strands forming the mesh at one part of said open-mesh body, compressible means located on the other side of said first means and seated against said first means, and third means located on the other side of said first means in spaced relation thereto, said third means being connected to said compressible means, being movable relative to said elongated member, and connectible in fixed relation to another part of said open-mesh body longitudinally spaced from said one part thereof.

8. A device as defined in claim 1, in which said compressible means comprises a helical compression spring having one end engaging said first means and extending in coiled relation around said elongated member, said third means being connected to the other end of said spring.