JPH085638B2 - Expansion / contraction position detector for container spreaders - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container spreader for loading and unloading a container mounted on a forklift truck, and more particularly to a telescopic position detector for detecting the telescopic position of the telescopic container spreader. Regarding the device.

[Prior art]

Generally, a container spreader is used as an attachment when a forklift truck is to carry a container. As one of the container spreaders, there is a telescopic container spreader.

As shown in Fig. 5, the above-mentioned telescopic container spreader
The 92 is mounted on the front part of the forklift truck 91 via a lift bracket 911 so as to be able to move up and down.

The container spreader 92 has a holder 921. As shown in FIG. 6, the holder 921 is formed in a tubular shape, and a rail 922 is slidably fitted therein via a rail pad 924. As a result, the container spreader 92 can be expanded and contracted in the lateral direction according to the length of the container 99 to be handled.

A twist lock 923 that can be engaged with a hanging hole (not shown) of the container 99 is provided at the tip of the rail 922.

A container spreader provided with an expansion / contraction position detection device for detecting the expansion / contraction position has been proposed (for example, Japanese Utility Model Laid-Open No. 62-168097).

By the way, the above-mentioned expansion / contraction position detecting device of the related art uses, for example, as shown in FIG.
32 and an expansion / contraction position detection sensor for detecting the expansion / contraction position of the container spreader 92 when the detection plate 932 approaches.
With 931.

The detection plate 932 has a container spreader 92 whose expansion / contraction position is set to, for example, 20 depending on the length of the container 99 to be handled.
The rails 922 are arranged at predetermined intervals along the side surface of the rail 922 so as to have feet or 40 feet.

The expansion / contraction position detection sensor 931 is attached to the side surface of the holder 921 by the bracket 933.

[Problems to be solved]

However, in the expansion / contraction position detecting device of the conventional container spreader, the expansion / contraction position detection sensor may not be able to operate accurately.

This point will be described in detail with reference to FIG. A clearance C for smoothly sliding the rail 922 is provided between the rail 922 and the rail pad 924. However, when the rail 922 is displaced due to wear of the rail pad 924, or when the rail 922 itself is bent and deformed due to the weight of the container 99, the expansion / contraction position detection sensor 931 and the detection plate 932 are Gap A between
Changes during work.

When the gap A changes in the direction of expanding beyond the rated operating distance of the expansion / contraction position detecting sensor 931,
The expansion / contraction position detection sensor 931 malfunctions. That is, even if the container spreader 92 is surely expanded / contracted, the expansion / contraction position detection sensor 931 does not detect the expansion / contraction position.

Also, when the gap A changes in the contracting direction,
The expansion / contraction position detection sensor 931 and the detection plate 932 may interfere with each other and be damaged.

In view of the above conventional problems, the present invention is to provide an expansion / contraction position detection device for a container spreader that can reliably operate the expansion / contraction position detection sensor regardless of the displacement of the rail with respect to the holder. .

[Means for solving problems]

According to the present invention, a rail provided with a twist lock at its tip is slidably fitted in a holder so that it can be expanded and contracted.
In the container spreader in which a plurality of detection plates are arranged along the expansion / contraction direction on the rail, and an expansion / contraction position detection sensor for detecting the expansion / contraction position by the proximity of the detection plates is arranged on the holder, The detection sensor is attached to an elastic bracket that constantly urges it in the rail direction, and a rail contact member that contacts the rail and maintains a constant relative distance between the telescopic position detection sensor and the rail is attached to the elastic bracket. It is an expansion / contraction position detecting device for a container spreader characterized by being attached.

What is most noticeable in the present invention is that the elastic bracket and the rail contact member are configured to constantly urge the expansion / contraction position detection sensor in the rail direction and to keep the relative distance between them constant.

In the present invention, as the expansion / contraction position detection sensor,
A proximity switch is mainly used, but a contactless micro switch or the like can also be used.

The proximity switch is a switch that outputs an output signal when the detection plate approaches within the operating distance and can detect the detection plate in a non-contact manner.

Examples of the proximity switch include an inductive proximity switch (see the embodiment) and a capacitance proximity switch.

In the present invention, the elastic bracket is a bracket having an elastic function for constantly urging the expansion / contraction position detection sensor in the rail direction. As means for imparting an elastic function to the elastic bracket, there is, for example, a method of manufacturing the elastic bracket itself from an elastic material such as spring steel (see the first embodiment). There is also a method of forming the elastic bracket by a bracket having no elastic function and an elastic body such as a coil spring, a disc spring, or a rubber plate attached to the bracket (see the second embodiment).

Further, in the present invention, the rail contact member is a member for contacting the rail to keep the relative distance between the telescopic position detection sensor and the rail constant. The relative distance in this case means a gap between the expansion / contraction position detection sensor and the rail, which allows the expansion / contraction position detection sensor to detect the detection plate within the operating distance.

The rail contact member is provided with a roller that rolls in contact with the rail (see the first embodiment) and a pad that is slid in contact with the rail (see the second embodiment).
and so on.

[Action]

In the present invention, the elastic bracket constantly urges the expansion / contraction position detection sensor in the rail direction. On the rail,
The rail contact member makes contact and maintains the relative distance between the telescopic position detection sensor and the rail constant.

And when the rail is displaced with respect to the holder,
The elastic bracket elastically deforms according to the displacement of the rail. As a result, the relative distance between the telescopic position detection sensor and the rail is always kept constant regardless of the displacement of the rail. That is, the gap between the expansion / contraction position detection sensor and the detection plate is constant.

Therefore, during expansion and contraction, the expansion / contraction position detection sensor detects the detection plate without malfunctioning. Further, there is no possibility that the detection plate and the expansion / contraction position detection sensor interfere with each other.

〔effect〕

Therefore, according to the present invention, it is possible to provide an expansion / contraction position detection device for a container spreader that can reliably operate the expansion / contraction position detection sensor regardless of the displacement of the rail with respect to the holder.

〔Example〕

First Embodiment An expansion / contraction position detecting device for a container spreader according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

The device of this example has rails as shown in FIGS. 1 and 2.
A plurality of detection plates 32 arranged on the side surface of the container 922 along the expansion / contraction direction of the container spreader 92, and the detection plates.
An expansion / contraction position detection sensor 31 for detecting the expansion / contraction position of the container spreader 92 by the proximity of 32. The expansion / contraction position detection sensor 31 is attached to the holder 921 by the elastic bracket 1 that constantly urges the expansion / contraction position detection sensor 31 toward the rail 922. Further, a rail contact member 2 that is in contact with the rail 922 and holds the relative distance B between the expansion / contraction position detection sensor 31 and the rail 922 constant is attached to the elastic bracket 1.

In this example, an inductive proximity switch is used as the expansion / contraction position detection sensor 31. Although not shown, the expansion / contraction position detection sensor 31 has an induction type detection circuit and a detection coil connected to the induction type detection circuit.

A metal rectangular plate is used as the detection plate 32 detected by the expansion / contraction position detection sensor 31. The detection plate 32 is arranged on the lower side of the side surface of the rail 922 so as not to interfere with the roller 22 described later and the rail pad 924 described above.

As shown in FIG. 2, the elastic bracket 1 is formed of spring steel into an L-shaped plate. The base of the elastic bracket 1 is fixed to the side surface of the holder 921 by the fixing bolt 11.

Further, as shown in FIG. 3, the detection plate 32 is fixed to the tip of the elastic bracket 1 by a fixing nut 12.
Telescopic position detection sensor corresponding to the mounting height position of
31 is attached. The expansion / contraction position detection sensor 31 is arranged so as to maintain a relative distance B with the rail 922.
The relative distance B is set within the rated operating distance of the expansion / contraction position detection sensor 31.

The rail contact member 2 is composed of a roller bracket 21 extending above the elastic bracket 1 and a roller 22 rotatably supported on the tip of the roller bracket 21. The roller 22 is arranged so as to roll on contact with the side surface of the rail 922. The base of the roller bracket 21 is fastened and fixed together with the elastic bracket 1 by the fixing nut 12. Further, a shim 13 for adjusting the bending amount of the elastic bracket 1 is interposed between the roller bracket 21 and the elastic bracket 1.

 Others are the same as the above-mentioned conventional example.

Since the device of this example is configured as described above, the following operational effects are exhibited.

That is, the roller 22 of the rail contact member 2 is biased toward the rail 922 by the elastic bracket 1. When the expansion / contraction of the container spreader 92 is operated by operating the expansion / contraction actuator, the roller 22 rolls while contacting the middle portion of the side surface of the rail 922.

When the container spreader 92 is expanded and contracted, the roller 22 is in contact with the rail 922 in this way, so the relative distance B between the expansion / contraction position detection sensor 31 and the rail 922 is not changed and is kept constant. . Therefore, the gap A between the expansion / contraction position detection sensor 31 and the detection plate 32 is also constant.

When the expansion / contraction position detection sensor 31 and the detection plate 32 face each other during the expansion / contraction, the expansion / contraction position detection sensor
The alternating magnetic field generated from the 31 detection coils is the detection plate
Interlink with 32. As a result, an induced current flows in the detection plate 32. Then, the expansion / contraction position detection sensor 31 senses that energy has been lost from the detection coil, and detects the detection plate 32 arranged at a desired expansion / contraction position.

Further, when the rail 922 is displaced with respect to the holder 921 due to wear of the rail pad 924 or bending deformation of the rail 922 itself, the elastic bracket 1 is elastically deformed according to the displacement of the rail 922.

Therefore, the relative distance B between the expansion / contraction position detection sensor 31 and the rail 922 is always kept constant regardless of the displacement of the rail 922. That is, the gap A between the expansion / contraction position detection sensor 31 and the detection plate 32 is always constant.

Therefore, when the container spreader 92 is expanded or contracted, the expansion / contraction position detection sensor 31 does not malfunction, and the detection plate is detected.
Detect 32 accurately. Further, there is no possibility that the expansion / contraction position detection sensor 31 and the detection plate 32 interfere with each other.

Therefore, the expansion / contraction position detection sensor 31 can be reliably operated.

Further, when adjusting the clearance C between the rail pad 924 and the rail 922, it is not necessary to care about the gap A as in the conventional case. Therefore, the clearance C can be easily adjusted. Also, the frequency of adjusting the clearance C is significantly reduced.

Second Embodiment An expansion / contraction position detecting device for a container spreader of this embodiment will be described with reference to FIG.

In this example, instead of the elastic bracket 1 and the rail contact member 2 shown in the first embodiment, a seesaw-shaped elastic bracket 4 and a rail contact member 5 provided with a pad 52 are provided.
To use.

That is, as shown in FIG. 4, the elastic bracket 4 is first attached to the holder 921. The elastic bracket 4 includes a support bracket 43 protruding from the side surface of the holder 921, a sensor bracket 41 mounted in a seesaw shape by the support bracket 43, a base portion of the sensor bracket 41 and the holder 921.
And a guide rod 44 for guiding the coil spring 42.

At the tip of the sensor bracket 41, the extension / contraction position detection sensor 31 shown in the first embodiment and the rail contact member 5 are provided.
And attach.

The rail contact member 5 includes a pad bracket 51 extending above the sensor bracket 41, as shown in FIG.
A pad 52 fixed to the pad bracket 51.

 Others are the same as those in the first embodiment.

Since the expansion / contraction position detecting device of this example is configured as described above, the seesaw-type sensor bracket 41 is biased by the coil spring 42 so that the tip end portion thereof rotates in the rail 922 direction. . Therefore, the expansion / contraction position detection sensor 31 attached to the sensor bracket 41 is constantly urged toward the rail 922. The rail contact member 5 secures a fixed relative distance B between the extension / contraction position detection sensor 31 and the rail 922.

Therefore, when the container spreader is expanded or contracted, the pad 52 of the rail contact member 5 slides on the side surface of the rail 922 to keep the relative distance B constant.

Therefore, the expansion / contraction position detection sensor 31 can be reliably operated regardless of the displacement of the rail 922 with respect to the holder 921.

Further, the same effect as that of the first embodiment can be obtained.

[Brief description of drawings]

1 to 3 show an expansion / contraction position detecting device for a container spreader according to the first embodiment. FIG. 1 is a plan sectional view of a main part thereof, FIG. 2 is a side view of the main part, and FIG. 2 is a sectional view taken along the line XX in FIG. 2, FIG. 4 is a sectional plan view of a main portion of the expansion / contraction position detecting device according to the second embodiment, FIGS. 5 and 6 show a conventional example, and FIG. 5 is a container spreader. FIG. 6 is a side view of a forklift truck in which is mounted, and FIG. 6 is an enlarged plan sectional view of a main part of the container spreader. 1 ...... Elastic bracket, 2 ...... Rail contact member, 31 ...... Expansion and contraction position detection sensor, 32 ...... Detection plate, 4 ...... Elastic bracket, 5 ...... Rail contact member, 92 ...... Container spreader, 921 ...... Holder, 922 …… Rail, 923 …… Twist lock, B …… Relative distance,

Claims (1)

[Claims] 1. A rail having a twist lock arranged at its tip end is slidably inserted into a holder so that the rail can be expanded and contracted.
In the container spreader in which a plurality of detection plates are arranged on the rail along the expansion / contraction direction, and an expansion / contraction position detection sensor for detecting the expansion / contraction position by the proximity of the detection plates is arranged on the holder. The detection sensor is attached to an elastic bracket that constantly urges it in the rail direction, and a rail contact member that contacts the rail and maintains a constant relative distance between the telescopic position detection sensor and the rail is attached to the elastic bracket. An expansion / contraction position detection device for container spreaders characterized by being installed.