Patent Publication Number: US-2022231489-A1

Title: Cable towing machine and cable laying method

Description:
TECHNICAL FIELD 
     The present disclosure relates to a cable pulling machine that pulls up a cable into midair and a cable installation method that suspends a cable in bridged relation in midair. 
     BACKGROUND ART 
       FIG. 1  is a diagram illustrating construction work of pulling a cable  12  from a utility pole  10  into a house  11 , which involves crossing a road. When such construction work is performed, a road  17  is closed to vehicular traffic, the cable  12  is allowed to drag on the road  17 , a lift rope is connected to the cable  12 , and a worker  21  is moved up to a high place by a high-place service vehicle  22  or the like, pulls up the cable  12  with human power, and fixes the cable  12  at the high place. At that time, when a vehicle  23  running on the road  17  does not stop and enters a working area, the vehicle  23  is caught in the cable  12  to result in an accident. 
       FIG. 2  is a diagram illustrating construction work of pulling the cable  12  from the utility pole  10  into the house  11 , which involves crossing a road and in which the worker  21  does not pull the cable  12 . In the construction work in  FIG. 2 , a cable pulling machine  25  as described in NPL 1 is used. However, in the construction work as illustrated in  FIG. 2  also, between the road  17  and the house  11 , the cable  12  is merely moved crosswise along the ground. Consequently, an operation of pulling up the cable  12  to the high place is performed by the worker  21  with human power, and it is difficult to prevent the accident described above. 
     CITATION LIST 
     Non-Patent Literature 
     
         
         [NPL 1] http://www.hct.ecl.ntt.co.jp/panel/pdf/2_Ea_3_1-1.pdf (retrieved Apr. 17, 2019). 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problem 
     To avoid the accident, a pulling machine capable of pulling up a cable without interposition of a worker is required.  FIG. 3  is a diagram illustrating such a pulling machine  100 . By installing the pulling machine  100  at a high place and causing the pulling machine  100  to pull the cable, the cable can be pulled up without interposition of a worker. The pulling machine  100  has two roller portions (c). By holding a cable (a) or a traction rope (b) between the roller portions (c) and rotating the roller portions (c), the cable (a) or the traction rope (b) is pulled in a direction (e). However, when the pulling machine  100  is installed at a high place, a connection portion (d) between the hard cable (a) which is less plastically deformable and the traction rope (b) which is more plastically deformable may be caught in the roller portions (c) during pulling to stop the pulling. This is because, unlike in the cable pulling machine (above ground) in NPL 1, the connection portion (d) tends to pass at an acute angle between the roller portions (c). Note that the “acute angle” refers to a state in which an angle θ formed between a straight line connecting respective centers (o) of the roller portions (c) and the cable (a) is less than 45°. 
     Specifically, when a pulling machine as illustrated in  FIG. 3  is installed at a high place, it is possible to prevent an accident as described above, but another problem of a stop of pulling arises. To solve the problem described above, an object of the present invention is to provide a cable pulling machine that can avoid, even when installed at a high place, a stop of pulling and a cable installation method. 
     Means for Solving the Problem 
     To attain the object described above, in the cable pulling machine according to the present embodiment, a guide is provided in a cable introduction portion to prevent a connection portion from being introduced at an acute angle between roller portions. 
     Specifically, the cable pulling machine according to the present invention is a cable pulling machine including: two roller portions having outer peripheries between which a cable is to be held; and a guide that introduces the cable between the roller portions, the guide adjusting an angle formed between a straight line connecting respective centers of the roller portions and the cable introduced between the roller portions to a value of not less than 45° and not more than 90°. 
     Even when the cable pulling machine is installed at a high place, the guide increases the angle at which the connection portion is introduced between the roller portions and reduces occurrence of a situation in which the connection portion is caught in the roller portions. Therefore, the present invention can provide the cable pulling machine that can avoid, even when installed at a high place, a stop of pulling. 
     In the cable pulling machine according to the present invention, the guide has a groove that guides the cable to a center of the outer periphery of each of the roller portions. When the cable is pulled, the cable does not meander, and a force from the roller portions is easily transmitted to the cable. 
     In the cable pulling machine according to the present invention, the guide has an uneven portion in the groove. When the cable is pulled, the cable does not meander, and the force from the roller portions is easily transmitted to the cable. The uneven portion can remove a deposit on the cable therefrom. 
     In the cable pulling machine according to the present invention, at least one of the roller portions has a plurality of recesses which are formed in a center of the outer periphery thereof and into which the cable is to fit. When the cable is pulled, the cable does not meander, and the force from the roller portions is easily transmitted to the cable. 
     The cable pulling machine according to the present invention further includes: a hook that allows the cable pulling machine to be hung on an existing aerial cable. This allows the present cable pulling machine to be easily installed at a high place. 
     A cable installation method according to the present invention is a cable installation method that uses the cable pulling machine described above to pull up the cable into midair, the cable installation method including: connecting a traction rope to a tip end of the cable; holding the traction rope between the two roller portions of the cable pulling machine and disposing the traction rope in the guide; hanging the hook on the aerial cable to install the cable pulling machine in midair; and rotating the roller portions of the cable pulling machine to pull the traction rope and pulling the cable pulled by the traction rope into the roller portions to pull up the cable to a level not lower than a predetermined height. 
     The present cable installation method, which uses the cable pulling machine described above, can avoid a stop of pulling even when the cable pulling machine is installed at a high place, allows the cable to be pulled up to the high place without the need for human power of a worker, and can prevent the accident described above. Therefore, the present invention can provide the cable installation method that can avoid, even when the cable pulling machine is installed at the high place, the stop of pulling. 
     Note that the invention described above can be combined as far as possible. 
     Effects of the Invention 
     The present invention can provide a cable pulling machine that can avoid, even when installed at a high place, a stop of pulling and a cable installation method. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating construction work of pulling a cable from a utility pole into a house. 
         FIG. 2  is a diagram illustrating construction work of pulling the cable from the utility pole into the house by using a cable pulling machine. 
         FIG. 3  is a diagram illustrating a cable pulling machine related to the present invention. 
         FIG. 4  is a diagram illustrating a cable pulling machine according to the present invention. 
         FIG. 5  is a diagram illustrating the cable pulling machine according to the present invention. 
         FIG. 6  is a diagram illustrating a guide of the cable pulling machine according to the present invention. 
         FIG. 7  is a diagram illustrating the cable pulling machine according to the present invention. 
         FIG. 8  is a diagram illustrating the cable pulling machine according to the present invention. 
         FIG. 9  is a diagram illustrating a method of operating the cable pulling machine according to the present invention. 
         FIG. 10  is a flow chart illustrating construction work of pulling a cable from a utility pole into a house by using the cable pulling machine according to the present invention. 
         FIG. 11  is a diagram illustrating the construction work of pulling the cable from the utility pole into the house by using the cable pulling machine according to the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Referring to the accompanying drawings, embodiments of the present invention will be described. The embodiments to be described hereinbelow are examples of the present invention, and the present invention is not limited to the following embodiments. It is assumed that components denoted by the same reference numerals in the present description and the drawings mutually denote the same components. 
     First Embodiment 
       FIG. 4  is a diagram illustrating a cable pulling machine  101  in the present embodiment. The cable pulling machine  101  is a cable pulling machine including two roller portions c having outer peripheries between which a cable a is to be held and a guide f that introduces the cable a between the roller portions c. The guide f adjusts an angle θ formed between a straight line connecting respective centers o of the roller portions c and the cable a introduced between the roller portions c to a value of not less than 45° and not more than 90°. 
     Even when the cable machine  101  is installed at a high place, the presence of the guide f allows the angle θ to be larger than that in a cable pulling machine  100  in  FIG. 3 . As a result, a connection portion d is not introduced at an acute angle between the roller portions c. In other words, the cable a, a traction rope b, and the connection portion d, which are introduced from directions closer to a perpendicular to the straight line connecting the respective centers of the two roller portions c, are consequently introduced (pulled) under no load between the two roller portions c. Therefore, it is possible to prevent the connection portion d from being caught in the roller portions c. 
     Second Embodiment 
     When the pulling is performed using the roller portions c, it may be possible that the cable a, the traction rope b, or the connection portion d meanders from side to side and a force of the roller portions c cannot be sufficiently transmitted thereto. This results in a need for a functional portion that prevents the cable a, the traction rope b, and the connection portion d from meandering when the pulling is performed using the roller portions c. The embodiment will describe a first mode of the functional portion. 
       FIG. 5  is a diagram illustrating a cable pulling machine  102  in the present embodiment. The cable pulling machine  102  is characterized in that, in contrast to the cable pulling machine  101  in  FIG. 4 , the guide f has a guide groove g for guiding the cable a to a center of each of the outer peripheries of the roller portions c. A width of the guide groove g is adjusted to be slightly larger than a diameter or thickness of an object to be pulled (the cable a, the traction rope b, and the connection portion d) to allow the object to be pulled to fit in the guide groove g. 
     By thus providing the guide f with the guide groove g, when the object to be pulled is introduced between the roller portions c, the object to be pulled does not meander and is introduced between the roller portions c along the guide groove g. As a result, the object being pulled is guided to an appropriate position (place where a pulling force is easily transmitted thereto) between the roller portions c, which results in easier pulling. In other words, there is no need to enlarge a power source. 
     Also, as illustrated in  FIG. 6 , the guide f is characterized by having an uneven portion j in the guide groove g. By providing a portion of an entrance-side tip end of the guide groove (g) with minute unevenness (uneven portion j), it is possible to remove a deposit clinging to the cable a when the cable a is pulled. 
     Third Embodiment 
     The present invention will describe a second mode of the functional portion.  FIG. 7  is a diagram illustrating a cable pulling machine  103  in the present embodiment. The cable pulling machine  103  is characterized in that, by contrast to the cable pulling machine  101  in  FIG. 4 , at least one of the roller portions c has a plurality of recesses h which are formed in the center of the outer periphery and into which the cable a is to fit. A width of each of the recesses h is adjusted to be slightly larger than the diameter or thickness of the object to be pulled (the cable a, the traction rope b, or the connection portion d) to allow the object to be pulled to fit in the recess h. 
     Note that each of the recesses h is not a groove completely extending around the outer periphery of the roller portion c. The recesses h are aligned so as to round the outer periphery of the roller portion c. This is because, to pull the cable a, the roller portion c also requires a flat portion without the recesses h. 
     Since the roller portions c are thus provided with the recesses h, when introduced between the roller portions c, the object to be pulled fits into the recesses h to be introduced between the roller portions c without meandering. Consequently, the object to be pulled is guided to an appropriate position (place where the pulling force is easily transmitted) between the roller portions c, which results in easier pulling. In other words, there is no need to enlarge the power source. Note that, in  FIG. 7 , one of the roller portions c is provided with the recesses h, but both of the roller portions c may also have the recesses h. 
     Fourth Embodiment 
       FIG. 8  is a diagram illustrating a cable pulling machine  104  in the present embodiment.  FIG. 8(A)  is a front view of the cable pulling machine  104 .  FIG. 8(B)  is a side view of the cable pulling machine  104 . In contrast to the cable pulling machines ( 101  to  103 ) in  FIGS. 4, 5, and 7 , the cable pulling machine  104  is characterized by further including a hook k to be hung on an existing aerial cable  15 . 
     A casing p stores therein a power source, a control substrate, and other parts. The hook k includes a pulling machine installation hook k 1  to be engaged with a tool (see  FIG. 9 ) used to hang the pulling machine  104  on the existing aerial cable  15 . 
       FIG. 9  is a diagram each illustrating an operation of installing the cable pulling machine  104  on the aerial cable  15 .  FIG. 9(A)  is a diagram when the hook k is about to be hung on the aerial cable  15 .  FIG. 9(B)  is a diagram after the hook k is hung on the aerial cable  15 . First, as illustrated in  FIG. 9(A) , when a hook  32  of a tool  31  is engaged with the pulling machine installation hook k 1  and lifted upward, an open/close portion k 2  of the hook k is opened. Through the opened open/close portion k 2 , the aerial cable  15  is inserted to hang the cable pulling machine  104  on the aerial cable  15 . Subsequently, as illustrated in  FIG. 9(B) , the tool  31  is pulled down to allow the hook  32  to come off the pulling machine installation hook k 1 , and the open/close portion k 2  of the hook k is closed. A worker uses the tool  31  to install the cable pulling machine  104  on the aerial cable  15 , as illustrated in  FIG. 9 . 
     Fifth Embodiment 
       FIGS. 10 and 11  are diagrams illustrating a method of installing a cable by using the cable pulling machine  104 . In the cable installation method in the present embodiment, the traction rope b is connected to a tip end of the cable a. 
     Then, the traction rope b is held between the two roller portions c of the cable pulling machine ( 101 ,  102 , or  103 ) and disposed in the guide f. 
     Then, as illustrated in  FIG. 9 , the hook k is hung on the aerial cable  15  to install the cable pulling machine ( 101 ,  102 , or  103 ) in midair. 
     Then, the roller portions c of the cable pulling machine are rotated to pull the traction rope b and further pull the cable a pulled by the traction rope b into the roller portions c. 
     The cable installation method in the present embodiment is characterized by thus pulling up the cable a to a level equal to or higher than a predetermined height. 
     Using  FIGS. 10 and 11 , a more detailed description will be given. 
     The worker  21  completes an operation performed in a house and on a wall surface of the house (Step S 01 ). 
     The worker  21  cuts the cable a to any given length in the house (Step S 02 ). 
     The worker  21  cuts the traction rope b to any given length in the house (Step S 03 ). 
     The worker  21  connects the cable a and the traction rope b (Step S 04 ). 
     The worker  21  crosses the road  17 , while allowing the traction rope to drag on the road  17  (Step S 05 ). 
     The worker  21  inserts the traction rope b between the two rollers c of the cable pulling machine  104  (Step S 06 ). 
     The worker  21  engages the hook  32  of the tool  31  with the pulling installation hook k 1  of the cable pulling machine  104  (Step S 07 ). 
     The worker  21  extends the tool  31  and hangs the hook k of the cable pulling machine  104  on the aerial cable  15  (Step S 08 ). 
     The worker  21  contracts the tool  31  (Step S 09 ). 
     The worker  21  operates the cable pulling machine  104  by using a wireless remote control switch  33  to start a pulling operation (Step S 10 ). 
     The traction rope b and the cable a are stretched tight up to a level not lower than a predetermined height (height at which a vehicle using the road  17  is not caught therein) (Step S 11 ). 
     The worker  21  operates the cable pulling machine  104  by using the wireless remote control switch  33  to stop the pulling operation (Step S 12 ). 
     The worker  21  makes preparations for working at a high place, such as preparing a high-place service vehicle (Step S 13 ). 
     The worker  21  is moved up to a high place by the high-place service vehicle or the like (Step S 14 ). 
     The worker  21  removes the cable a from the cable pulling machine  104  (Step S 15 ). 
     The worker  21  fixes the cable a to metal fittings of the utility pole  10  or the like (Step S 16 ). 
     The worker  21  removes the cable pulling machine  104  from the aerial cable  15  (Step S 17 ). 
     The worker  21  is moved down by the high-place service vehicle or the like (Step S 18 ). 
     The present cable installation method uses the cable pulling machine  104 , and therefore can avoid a stop of pulling even when the cable pulling machine  104  is installed at a high place, pull up the cable a to a high place without the need for human power of the worker  21 , and prevent the accident described above. 
     REFERENCE SIGNS LIST 
     
         
         a Cable 
         b Traction rope 
         c Roller portion 
         d Connection portion 
         e Pulling direction 
         f Guide 
         g Guide groove 
         h Recess 
         j Uneven portion 
         k Hook 
         k 1  Pulling machine installation hook 
         k 2  Open/close portion 
           10  Utility pole 
           11  House 
           12  Cable 
           15  Aerial cable 
           17  Road 
           21  Worker 
           22  High-place service vehicle 
           23  Vehicle 
           25  Cable pulling machine 
           31  Tool 
           32  Hook 
           33  Wireless remote control switch 
           100  to  104  Cable pulling machines