JP3065840B2 - Toothed cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed cable. More specifically, the present invention relates to a toothed cable having an improved durability, which is used for driving and pushing an operated device.

[0002]

2. Description of the Related Art Spiral teeth are formed on the outer periphery of a core cable to push and pull an operated device, such as when opening and closing a front window of a cabin of a construction machine such as a power shovel (usually). , Which is formed by spirally winding a steel wire). That is, a driving gear is meshed with the spiral tooth, and the toothed cable is pushed and pulled by rotating the gear manually or by a motor (see Japanese Patent Application Laid-Open No. 4-208632).

As shown in FIG. 7, the toothed cable 51 has a cable end fitting for connecting to a device to be operated at its distal end.
52 is fixed, and is used by being inserted into a guide tube 53 installed in a cabin of a power shovel or the like. In this case, it is almost impossible to attach the cable end fitting 52 after inserting the toothed cable into the guide tube 53 previously mounted in the cabin,
Since 52 is much larger than the outer diameter of the toothed cable 51, it cannot be inserted into the guide tube 53.

Therefore, as shown in FIG.
By removing the spiral teeth 54 in the vicinity of the connecting portion of the guide tube 53 (hereinafter referred to as a spiral tooth removal portion 51a), only the cable end fitting 52 is brought out of the guide tube 53, and the slit 53a of the guide tube 53 is The toothed cable 51 is inserted so that the spiral tooth removing portion 51a passes.

The toothed cable 51 shown in FIG. 3 constructed as described above has, among the helical tooth removing portions 51a having a smaller section modulus than other portions when pushed, particularly a cable end fitting 52.
Since the bending concentrates on a portion close to the spiral tooth, the helical tooth removing portion 51a may be fatigued and damaged by repeated push-pull operations.

A toothed cable 61 shown in FIG. 4 which solves such a problem is known. In this toothed cable 61, a coil spring 63 for reinforcement is wound around only the connection end with the cable end fitting 62 while forming a spiral tooth removal portion 61a of a required length, and the mounting hole of the cable end fitting 62 is further placed thereon. It is inserted into and crimped.

[0007]

However, it has been found that a sufficient reinforcing effect cannot be obtained only by the coil spring 63 (FIG. 4). In addition, if the diameter of the element wire of the coil spring 63 is increased to increase the bending rigidity, it becomes difficult to mount the reinforcing member, and stress is concentrated on a boundary portion of the core cable 64 of the toothed cable with the coil spring 63. It is not preferable because another problem occurs.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has a toothed cable which has improved durability by preventing fatigue breakage at a connection portion with a cable end fitting and is easy to assemble. The purpose is to provide.

[0009]

A toothed cable according to the present invention is a toothed cable in which spiral teeth are formed on the outer peripheral portion except for the vicinity of the distal end, and a cable end fitting is provided at the distal end. A coil spring is fitted near the attachment portion of the cable end fitting in the toothed cable, and a portion from the rear end of the cable end fitting to the tip of the spiral tooth forming portion via the coil spring is made of a heat-shrinkable synthetic resin. It is characterized by being tightly covered with a tube.

[0010]

In the toothed cable according to the present invention, a coil spring is fitted to a connection portion of the spiral tooth removing portion with the cable end fitting, and the leading end of the spiral tooth passes through the spiral tooth removing portion from the rear end of the cable end fitting. The entire part up to the part is tightly covered with a shrinkable tube made of heat-shrinkable synthetic resin, so the connection part with the cable end fitting is partially reinforced more strongly by the coil spring, and the shrinkable tube is placed around the constricted part. The rigidity of the entire constricted portion is increased due to close contact. Furthermore, in the present invention, since the flexural rigidity of the coil spring is improved by the contraction tube restraining the coil spring from the outside, the portion where bending stress is most likely to concentrate is particularly reinforced, so that extremely high durability is achieved. available.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partially cutaway front view showing an embodiment of the toothed cable of the present invention, and FIG. 2 is a sectional view of the toothed cable II of FIG.
FIG. 3 is a partially cutaway front view of a toothed cable used in Comparative Example 1, FIG. 4 is a partially cutaway front view of a toothed cable used in Comparative Example 2, and FIG. FIG. 6 is a cross-sectional explanatory view showing a test device for performing a durability test of a toothed cable used in Example 3; FIG.

In FIG. 1, reference numeral 1 denotes a toothed cable,
The core cable 2 is twisted from a plurality of steel wires into a rope having a single twist structure. A steel wire forming the helical teeth 3 is helically wound around the core cable 2 except for the ends. FIG. 2 shows a cross section of the toothed cable 1. The core cable 2 includes a plurality of strands 5 forming a second layer around the core wire 4 and the second strand 5.
A plurality of strands 6 forming the first layer are twisted around the outer periphery of the layer.

As shown in FIG. 1, near the tip of the spiral tooth removing portion 1a where the spiral tooth 3 is not formed,
A coil spring 7 is fitted around the core cable 2 so as to be in close contact therewith. The end of the toothed cable 1 integrated with the coil spring 7 in this manner is inserted into a mounting hole provided in the neck 9 of the cable end fitting 8 and then swaged and fixed.
Further, after a shrinkable tube 10 made of a heat-shrinkable synthetic resin such as polyethylene or polyvinyl chloride is covered from the rear end of the cable end fitting 8 to the front end of the portion where the spiral teeth 3 are formed, the tube is heated and shrunk from the outside. Is brought into close contact. Therefore, the ends of the neck portion 9 of the cable end fitting 8, the coil spring 7, the helical tooth removing portion 1a, and the helical tooth 3 forming portion are restrained by the contraction tube 10.

The core cord 2 has a so-called single twist structure, but the present invention is not limited to this structure.

The toothed cable 1 constructed as described above
Is slidably inserted into a guide cylinder (eg, 53 in FIG. 7), one end of which is connected to a driving unit and the other end is connected to a device to be operated, and is pushed and pulled from an end on the driving unit side. As a result, the operated device is operated.

Next, the toothed cable of the present invention will be described in more detail based on specific embodiments.

Example 1 Five toothed cables 1 of Example 1 shown in FIGS. 1 and 2 were manufactured as described above.

The diameter of the core cable 2 of the toothed cable is 2.6 mm.
The length of the exposed section A of the core cable 2 is 30 mm, the length B of the coil spring 7 exposed from the cable end fitting 8 is 10 mm, the outer diameter of the coil spring 7 is 3.8 mm, and the wire diameter is 0.5 mm. And the length of the shrink tube 10 was 40 mm.

COMPARATIVE EXAMPLE 1 As shown in FIG. 3, five toothed cables 51 which were the same as those of Example 1 except for having both a coil spring and a shrinkable tube were used.

COMPARATIVE EXAMPLE 2 As shown in FIG. 4, a toothed cable 61 having the same coil spring 63 as that of the first embodiment and no other contraction tube was used, and This book was used.

Comparative Example 3 As shown in FIG. 5, a coiled spring was not used, only a contraction tube 72 was provided, and five other toothed cables 71 identical to those in Example 1 were used.

The durability of Example 1 and Comparative Examples 1 to 3 was examined using a test apparatus shown in FIG. In each case, the number of samples was five.

In FIG. 6, toothed cables 1, 51, 61 and 71 (hereinafter, represented by 1) each having a cable end fitting 8 are passed through the inside of the insertion hole 22 of the duct tail 21, and
Is fixed to a pin 23 fixed to a wall or the like, and the end on the driving side is connected to a reciprocating drive to apply a constant cycle of compression and tension load, and five toothed cables of each example Was subjected to a durability test, and the number of times of durability and the state of damage were examined. As a test condition, the magnitude of the load was ± 23
0 N, load cycle 90 cpm, environmental temperature during test
At 25 ° C., the diameter of the pin 23 was 10 mm. The inside of the insertion hole 22 of the ductail 21 is formed to have a gentle taper shape without any protrusion. Table 1 shows the results.

[0025]

[Table 1]

From the results in Table 1, the durability numbers of Comparative Examples 1 to 3 are
5,000 to 7,400 times (all were completely broken in less than 7,400 times), whereas in the toothed cable of Example 1, the vicinity of the neck of the cable end was effectively reinforced.
Can withstand more than 105,000 times. In Example 1, two out of five pieces were broken by 107,000 times. At that point, the test was terminated, and the other three pieces were disassembled and investigated.

[0027]

The toothed cable of the present invention is strong against bending generated near the joint between the cable end fitting and the toothed cable when a compressive force is applied, and has extremely high durability.

Further, since commercially available coil springs and shrinkable tubes can be used, they can be easily manufactured by using a conventional manufacturing method.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a toothed cable of the present invention.

FIG. 2 is a sectional view of the toothed cable of FIG. 1 taken along the line II-II.

FIG. 3 is an example of a conventional toothed cable, and is a partially cutaway front view of the toothed cable used in Comparative Example 1.

FIG. 4 is another example of the conventional toothed cable, and is a partially cutaway front view of the toothed cable used in Comparative Example 2.

FIG. 5 is a partially cutaway front view of a toothed cable used in Comparative Example 3.

FIG. 6 is an explanatory sectional view showing a test device for performing a durability test of a toothed cable.

FIG. 7 is a partially cutaway perspective view showing insertion of the toothed cable of FIG. 3 into a guide cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toothed cable 1a Spiral tooth removal part 2 Core cable 3 Spiral tooth 7 Coil spring 8 Wire end fitting 10 Shrink tube

Continued on the front page (72) Inventor Masamichi Miyazaki 3-1-1 Ueno, Hirakata-shi, Osaka Komatsu Ltd. Osaka Plant (56) References JP-A-4-208632 (JP, A) Japanese Utility Model Showa 55- 26155 (JP, U) Japanese Utility Model 1-73515 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 1/00-1/28

Claims (1)

(57) [Claims] 1. A toothed cable in which spiral teeth are formed on an outer peripheral portion except for a vicinity of a distal end portion thereof, and a cable end metal fitting is provided at the distal end portion, wherein the cable end metal fitting is attached to the toothed cable. A coil spring is fitted in the vicinity of the portion, and a portion from the rear end of the cable end fitting to the tip of the spiral tooth forming portion via the coil spring is tightly covered with a tube made of a heat-shrinkable synthetic resin. Toothed cable.