NL1039239C2

NL1039239C2 - Wire end terminal for holding wire end.

Info

Publication number: NL1039239C2
Application number: NL1039239A
Authority: NL
Inventors: Johannes Hendrikus Eertman
Original assignee: Ropeblock B V
Priority date: 2011-12-13
Filing date: 2011-12-13
Publication date: 2013-06-17

Description

WIRE END TERMINAL FOR HOLDING WIRE END FIELD OF THE INVENTION

5 The invention relates to a wire end terminal for holding a wire end of a wire rope, for use in crane industry.

BACKGROUND

In the crane industry, several types of mechanisms are used for holding a wire end of a 10 wire rope, in a wire end terminal. One end of the wire rope is commonly coiled over a drum, while the second end that is being referred to as the wire end, is held in the wire end terminal. The terminal is passed over one or more sheaves in the crane and then is finally detachably connected to a socket (connection device) which is connected to the top of the crane or the crane block. Usually a hook is attached to the crane block. The terminal and 15 the socket can be designed to avoid rotating of the terminal. ‘Sheaves’ in this context are grooved wheels (reels) for holding and guiding the wire rope, such as in a pulley system.

With use, often the wire rope gets damaged at localized places, causing weak points for carrying loads. The wire ropes are commonly serviced by cutting out a length that includes 20 the terminal holding the wire end and the damaged portion creating a fresh wire end at the cut end. The fresh wire end then needs to be again coupled to a terminal, that can be easily passed over the sheave(s) to be finally attached to the connecting device.

FIG. 1A shows an exemplary terminal, that has a button 102 with two opposite faces 104a, 25 104b and a through hole 106 extending between the two faces 104a, 104b. The hole 106 has a first end 108a and a second end 108b at the faces 104a, 104b. The hole 106 is in the shape of a hollow frusto-cone, having a narrower end oriented towards the first end 108a and a wider end oriented towards the second end 108b. The conical angle 110 is substantially between 9.5 to 16 degrees. As illustrated in FIG. IB, for use, the wire end 112 30 can be inserted into the hole 106 from the first end 108a and a polyester resin can be poured into the hole 106 from the second end 108b, for at least partially encapsulating the wire end 112 with the resin. After solidification of the resin, the wire end 112 is securely held in the hole 106. The wire end 112 is usually unwound before the resin is poured, for increasing its diameter 116c before said encapsulation, so that more area of the wire end 1039239 2 112 is exposed for encapsulation. This improves the strength for holding the wire end 112 in the button 102. This aforesaid procedure of servicing a damaged wire rope 122 can be easily conducted in the field. The resin may be replaced by a low melting point metal alloy. This method of fixing the wire end 112 into the terminal gives high strength for carrying 5 loads and is preferred over known terminal wire ends that have wedge like gripping elements or toothed inner diameter (US2009/0304441 Al) as these will deform the wire rope resulting in lower allowable carrying loads.

The conical angle 110 between 9.5 and 16 degrees, together with a minimal wall thickness decides the dimensions of the button 102. The button 102 is generally made of a solid iron 10 alloy, where the internal frusto-conical shape is machined. The button 102 is generally scrapped, after is has been cut from the wire rope. The conical angle 110 along with the casting creates a normal force on the wire end 112, that helps to hold the wire end 112 within the button 102 when the wire rope 122 is under load.

15 The button 102 is internally profiled 114 near the second end 108b for receiving a threaded screw head 118 of an eye bolt 120 in the terminal. The eye bolt 120 is used for reeving the wire rope 122 with the terminal through the sheaves when setting up the crane, particularly for mobile cranes or when assembling a new crane or when changing the wire rope 122 of a crane. ‘Reeving’ in this context indicates pulling the wire rope 122 through the sheaves, 20 when setting up the crane. An iron wire or a nylon rope may be passed through the eye bolt 120 for reeving the thicker and heavier wire rope 122 of the crane, through the sheave(s).

For higher loads, a length 116a of the button 102 needs to be longer to accommodate a longer length of the wire end 112. Since the conical angle 110 must be maintained within 25 the specified range, when the length 116a of the button 102 is increased, the size of the second end 108b automatically increases, hence the width 116b of the button 102 also needs to be increased. When the size of the button 102 in terms of the length 116a and the width 116b is too large, it is difficult to reeve the terminal through the sheave(s). When the conical angle 110 is reduced lesser than the specified range, the wire end 112 undesirably 30 slips out from the button 102 when the wire rope 122 is under load, as the normal force is reduced.

Terminal wire ends that have no such conical angle 110 for introducing a normal force but are stepwise (DE861347C, DE678310C or US5000611A) are also less preferred as firstly the carrying load will be divided over the steps which limits the carrying load significantly 3 and secondly there will be no normal force introduced helping to hold the wire rope in the button both resulting in longer button lengths for obtaining the same carrying load.

SUMMARY OF THE INVENTION

5 According to a first aspect of the invention, a wire end terminal for holding a wire end of a wire rope is provided, for use in a crane industry. The terminal comprises a button having two opposite faces. A through hole extends between the two faces, with a first end and a second end at the two faces. The hole is in the shape of multiple hollow frusto-cones stacked along a longitudinal direction of the hole. A narrower end of each cone orients 10 towards the first end and a wider end of each cone orients towards the second end. A conical angle of each cone is substantially between 9.5 to 16 degrees.

For use, the wire end is inserted into the hole from the first end and a resin can be poured into the hole from the second end for at least partially encapsulating the wire end with the resin, such that the wire end is securely held in the hole after solidification of the resin.

15

According to an embodiment, the button is internally profiled proximate the second end for receiving a fitting end of an eye bolt. According to yet another embodiment, the fitting end is a threaded screw head.

20 According to yet another embodiment, the wire end can be unwound for increasing diameter, before the resin is poured.

According to yet another embodiment, all the conical angles for the multiple frusto-cones are not same. According to another embodiment, varying conical angles are arranged in a 25 predetermined order, to establish an improved load distribution between each cone.

According to yet another embodiment, a length of the button is substantially five times a diameter of the wire rope. According to yet another embodiment, the multiple frusto-cones are four in number.

According to yet another embodiment, the button is at least partially composed of an iron alloy having a tensile strength of at least 800 Newton/ mm2.

30 4

According to a second aspect of the invention, a method of securing the wire end into the wire end terminal described above, is provided. The method comprises the steps of inserting the wire end into the hole by the first end, pouring the resin from the second end into the hole for at least partially encapsulating the wire end and allowing the resin to 5 solidify for securing the wire end in the terminal.

According to an embodiment of the second aspect, the method further comprises a step of unwinding the wire end before pouring the resin, for increasing the diameter.

10 According to yet another embodiment of the second aspect, the resin is replaced by a low melting point metal alloy.

According to yet another embodiment of the second aspect, the resin includes at least one additive such as sand, for enhancing friction to hold the wire end in the button.

15

The hole in the shape of the multiple hollow frusto-cones instead of one hollow frusto-cone improves a holding strength of the wire end in the terminal, by increasing the length of the button for holding an increased length of the wire end. By using the multiple frusto-cone shape, the benefit of the normal force is made use of, by maintaining the conical angle of 20 each cone within the specified range. By using the multiple frusto-cone shape, the width of the button need not be increased when its length is increased. This helps to keep the button width narrower and this feature helps easier reeving of the terminal through the sheave(s).

25 The present invention consists of certain novel features and a combination of parts hereinafter fully described and illustrated in the accompanying drawings and particularly pointed out in the appended claims; it being understood that various changes in the details may be possible without departing from the scope of the invention or sacrificing any of the advantages of the present invention 30

BRIEF DESCRIPTION OF THE DRAWINGS

In the following drawings, same reference numbers generally refer to the same parts throughout. The drawings are not necessarily to scale, instead emphasis is placed upon illustrating the principles of the invention. The various embodiments and advantages of the 5 present invention will be more fully understood when considered with respect to the following detailed description, appended claims and accompanying drawings wherein: FIG. 1A illustrates a cross sectional side view of a button, showing a through hole in the 5 shape of a single hollow frusto-cone.

FIG. IB illustrates FIG. 1A, when holding the wire end of the wire rope.

FIG. 2A illustrates a cross sectional side view of a button, according to an embodiment of 10 the invention, showing a through hole in the shape of multiple and stacked hollow ffusto-cones.

FIG. 2B illustrates FIG. 2A, when holding the wire end of the wire rope.

15 DETAILED DESCRIPTION

The following description presents several preferred embodiments of the present invention in sufficient detail such that those skilled in the art can make and use the invention.

Before describing in detail embodiments that are in accordance with the present invention, it should be noted that all of the figures are drawn for ease of explanation of the basic 20 teachings of the present invention only. The extension of the figures with respect to the number, position, relationship and dimension of the parts of the preferred embodiment will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength and similar requirements will likewise be within 25 the skill of the art after the following teachings of the present invention have been read and understood.

FIG. 2A shows a wire end terminal for use in a crane industry, according to an embodiment of the invention. The terminal has a button 202, that has two opposite faces 30 204a, 204b. A through hole 206 extends between the two faces 204a, 204b, with a first end 208a and a second end 208b at the two faces 204a, 204b. The button 202 may be a solid metallic block, with the hole 206. However, non-metallic blocks may also be used, for whatsoever reasons. The hole 206 is in the shape of a plurality of hollow frusto-cones 205 stacked along the longitudinal direction of the hole 206, where a narrower end of each cone 6 205 orients towards the first end 208a and a wider end of each cone 205 orients towards the second end 208b. A conical angle 210 of each cone 205 is substantially between 9.5 to 16 degrees. A ± 10% variation of the limits of this specified range may be included to account for the manufacturing variation. As illustrated in FIG. 2B, for use, the wire end 5 212 of the wire rope 222 can be inserted into the hole 206 from the first end 208a and a polyester resin can be poured into the hole 206 from the second end 208b for at least partially encapsulating the wire end 212 with the resin. The wire end 212 is securely held in the hole 206 after solidification of the resin. The resin may include at least one additive for enhancing friction to hold the wire end 212 within the button 202. The additive may be 10 silica or sand, though other suitable material(s) may also be used. The minimum diameter of the hole 206 is limited by the diameter 216c of the wire rope 222. The wire rope 222 may be metallic or non-metallic. The resin can be replaced by a low melting point metal alloy.

15 The button 202 is shown to be internally profiled 214 proximate the second end 208b, for receiving a fitting end 218 of an eye bolt 220. In this embodiment, the fitting end 218 is a threaded screw head. Any other arrangement for coupling the eye bolt 220 with the button 202 is also possible. An iron wire or a nylon rope may be passed through the eye bolt 220 for reeving the thicker and heavier wire rope 222 of the crane, through the sheave(s). For 20 reeving, other arrangements may also be used instead of the eyebolt 220, like for example, there could be two opposite holes for receiving a pin near the second end 208b, and the iron wire or the nylon rope can be attached to the pin.

The wire end 212 can be unwound from the second end 208b, for increasing the diameter 25 216c, before the resin is poured, so that the encapsulation by the resin is enhanced. This unwinding may be executed by hand or by using any kind of tool.

All the conical angles 210 for the multiple frusto-cones 205 need not be the same. For optimizing the load, different values may be adopted for the different conical angles 210 in 30 the button 202, while each conical angle 210 is maintained within the specified range of 9.5 to 16 degrees. According to an embodiment, for the multiple frusto-cones 205, varying conical angles 210 are arranged in a predetermined order to establish an improved distribution of load in each cone 205. However, using such different values for the conical angles 210 between the multiple frusto-cones 205 is likely to require proper optimization.

7

The length 216a of the button 202 may preferably be about five times the diameter 216c of the wire rope 222. However, other ratios may also be used. According to a preferred embodiment, the button 202 has four frusto-cones 205. The button 202 may be at least partially composed of an iron alloy having a tensile strength of at least 800 Newton/ mm2. 5

The conical angle 210 for each cone is maintained within the specified range of 9.5 to 16 degrees. With this shape of the multiple frusto-cones 205 instead of a single frusto-cone 205, when the length 216a of the button 202 is increased, the width 216b need not be increased, as the size of the second end 208b does not correspondingly increase. By 10 increasing the length 216a of the button 202 with the hole 206 being in the shape of increased number of such stacked hollow frusto-cones 205, higher load can be handled as longer length 216a of the wire end 212 can be held within the button 202. The maximum length 216a that can be used may however be limited by the convenience of usage over the sheave(s) in the crane. When the size of the button 202 is too large, it is difficult to reeve 15 through the sheave(s).

As to further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.

20

While the foregoing description presents preferred embodiments of the present invention along with many details set forth for purpose of illustration, it will be understood by those skilled in the art that many variations or modifications in details of design, construction and operation may be made without departing from the present invention as defined in the 25 claims. The scope of the invention is as indicated by the appended claims and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

1039239

Claims

A cable end connection for holding a cable end of a cable for use in a crane industry, the connection comprising: a socket having two opposite sides and a hole extending between the two sides, the hole having a first and a has a second end in the sides, wherein the hole is in the form of a variety of hollow flattened cones 10 stacked along a longitudinal direction of the hole and wherein a narrower end of each of the cones always faces the first end and a The wider end of each of the cones always faces the second end, with a conical angle of each of the cones being substantially between 9.5-16 degrees, whereby the cable end can be inserted into the hole of the first end when used. and a resin can be cast into the hole of the second end to at least partially encapsulate the cable end with the resin, the cable end after curing of the resin is held securely in the sock. 20

A cable end connection according to claim 1, wherein the socket is provided with a profile in the vicinity of the second end for receiving a fitting end of an eye bolt.

The cable end connection according to claim 2, wherein the matching end is a threaded screw head.

The cable end connection according to claims 1 to 3, wherein the cable end is unraveled to increase the diameter before the resin is cast. 30

The cable end connection according to claim 1 or 4, wherein all of the conical angles corresponding to the variety of flattened cones are not the same. 1039239

The cable end connection of claim 5, wherein the conical angles vary in a predetermined order.

Cable end connection according to claim 1,4 or 5, wherein a length of the socket 5 is substantially five times a diameter of the cable.

The cable end connection according to claims 1-7, wherein the socket is at least partially composed of an iron alloy that has a tensile strength of at least 800 Newton / mm 2. 10

The cable end connection according to claims 1-8, wherein the variety of flattened cones are 2, 3 or 4 flattened cones.

10. Cable end connection according to claim 9, wherein the variety of flattened cones are four flattened cones.

11. A method for securely securing the cable end into the cable end connection according to any of the preceding claims, wherein the method comprises the steps of: inserting the cable end into the hole through the first end; pouring the resin from the second end into the hole to at least partially encapsulate the cable end; Allowing the resin to cure to firmly secure the cable end in the joint.

The method of claim 11, further comprising a step of unraveling the cable end prior to casting the resin. 30

A method according to claims 11-12, wherein the resin is replaced by a metal alloy with a low melting point.

The method of claims 11-12, wherein the resin comprises at least one additive for increasing the friction to hold the cable end in the sock.

The method of claim 14, wherein the at least one additive comprises silicon. 1039239