Page 70 - Wire Rope News & Sling Technology - February 2019
P. 70

INVENTOR’S CORNER
         continued from previous page                         ingly, with wire 1 of the embodiment of the present inven-
         ed in figure 19, flat part F is illustrated as a substantially   tion, it is possible to suppress the load per unit area of contact
         arc-like portion having a curvature radius substantially the   between wire 1 and the direction turning member since side
         same as the radius of virtual circle C whose radius is a line   element wire 3b of side strand 3 is provided with smooth sur-
         connecting the contact point of flat part F and the center of   face P. While, in the conventional wires, the element wire of
         wire 1, but flat part F may also be a flat surface or a curved   the side strand has an angle with respect to the axis direction
         surface.  That  is,  it  suffices  that  smooth  surface  P formed   of wire 1 and consequently forms a strand track which is a
         by extending flat part F is formed in a flat shape such that   groove having an angle with respect to the movement direc-
         smooth  surface  P  makes  surface  contact  with  a direction   tion of wire 1, wire 1 of the embodiment of the present inven-
         turning member, and smooth surface P may have a curva-  tion can reduce formation of the strand track even when wire
         ture radius different from that of virtual circle C of wire 1. In   1 exerts a high load on the direction turning member or when
         addition, flat part F is provided to face the radially outside   the direction turning member is under a high temperature
         of the wire 1 at a part of side element wire 3b in the cir-  environment since the load of wire 1 exerted on the direction
                                                              turning member per unit area is reduced. Thus, since forma-
                                                              tion of the strand track on the direction turning member is
                                                              reduced, it is possible to reduce the groove movement sound
                                                              which is generated by movement of side element wire 3b of
                                                              wire 1 between the grooves of the strand track in the case
                                                              where wire 1 moves in the extending direction of wire 1 with
                                                              respect to the direction turning member.
                                                                It is to be noted that, in the embodiment illustrated in fig-
                                                              ures 19 and 20, smooth surface P has substantially the same
                                                              curvature radius as that of virtual circle C. However, as long
                                                              as the smooth surface makes contact with the direction turn-
                                                              ing member such that the load from wire 1 exerted on the di-
                                                              rection turning member per unit area is reduced, the smooth
                                                              surface of the embodiment of the present invention may be

          Figure 20: Side view of the wire of figure 19.
         cumferential direction, that is, at the outer periphery of side
         element wire 3b in the cross-section taken along a direction
         perpendicular to the extending direction of the side element
         wire 3b. Flat part F may not be located on virtual circle C as
         long as surface contact on the direction turning member can
         be achieved when wire 1 makes contact with the direction   Figure 21: Diagram for describing a pitch multiplying factor of a side
         turning  member.  In  addition, smooth  surface  P  is  formed   strand of the wire.
         such that flat part F formed in the above-mentioned fashion
         is extended in a direction parallel to the X axis of the extend-  formed to make surface contact with the direction turning
         ing direction of wire 1, and is capable of making surface con-  member, or smooth surface P may have a curvature radius
         tact with the slide movement groove of the direction turning   different from that of the outer periphery of wire 1, or may
         member as illustrated in figure 20.                  be formed in a planar shape. It is to be noted that in the case
           As illustrated in figures 19 and 20, side element wires 3b of   where smooth surface P is a horizontal surface, virtual circle
         side strand 3 are twisted together around core element wire   C is a circle which makes contact with the horizontal surface.
         3a of side strand 3 in a spiral form. Each side element wire   Smooth surface  P  is  configured  such  that  length  L1 of
         3b has smooth surface P formed at a portion located on the   smooth surface P in the X-axis direction is 4.8 to 11.0 times
         outer periphery of wire 1, and side element wire 3b has a   diameter D1 of side element wire 3b of side strand 3, and
         circular cross sectional shape at both sides of the portion of   the pitch multiplying factor of side strand 3 is 7.0 to 12.0
         smooth surface P in the X-axis direction (the horizontal direc-  times. Length L1 in the X-axis direction in which wire 1 ex-
         tion in figure 20). Thus, a plurality of smooth surfaces P are   tends on smooth surface P is the length between both ends
         formed in the X-axis direction and the circumferential direc-  of smooth surface P in the X axis direction of wire 1 as illus-
         tion of wire 1 with a plurality of side element wires 3b which   trated in figure 20, and diameter D1 of side element wire 3b
         are exposed at the outer periphery of wire 1 at the portions   is the outer diameter of side element wire 3b having smooth
         located on the outer periphery of wire 1 which have a pos-  surface P as illustrated in figure 19 and figure 20. In addi-
         sibility of making contact with the direction turning member,   tion, as illustrated in figure 21, the pitch multiplying factor
         as illustrated in figure 20. It is to be noted that, as long as   of side strand 3 is a value obtained by dividing strand pitch
         the effects described later can be achieved, the manufactur-  length L2 of side strand 3 by outer diameter D2 of wire 1,
         ing method of wire 1 having smooth surface P is not limited,   and, in the present embodiment, the diameter of virtual cir-
         and for example, such wire 1 can be formed through drawing
         with use of dies, swaging, cassette roller dies working and the
         like after core strand 2 and side strand 3 are twisted together.
           Smooth surface P which is formed in the above-mentioned
         manner makes surface contact with the direction turning
         member when wire 1 makes contact with the direction turn-
         ing member not illustrated (the surface of the guide groove of
         the direction turning member which guides wire 1). Accord-

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