JP2003063793A - Contact detecting sensor for fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact detecting sensor for a fork capable of safely inserting the fork into an inserting port of a pallet if a slight degree of contact is present and hardly causing a drop in workability. SOLUTION: This contact detecting sensor 12 for the forklift detects the contact of a fork 4 with the pallet by detecting the move of a contact member 13 fitted to the tip of the fork. The contact member 13 is movably fitted to the fork 4 through an elastic member 18. Tapered surfaces 15b, 16a, 16b tapered toward the tip of the contact member 13 are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact detection sensor for a fork.

[0002]

2. Description of the Related Art Conventionally, when using a forklift,
A pallet that has already been loaded and is placed in a predetermined place is scooped with a fork, and the scooped load is transported to a destination to be unloaded together with the pallet. And among these forklifts, there are those that are driven unattended using magnetic induction, etc.,
In an unmanned forklift, it is extremely important to ensure the safety of the work of scooping a loaded pallet with a fork. Each of the forks in which a plurality of forks are arranged in parallel is generally supported by a lift bracket that moves up and down while being guided by a mast so that the fork cannot be displaced.

In the scooping work of the pallet with the forks, although not shown, the forks are individually inserted from the insertion openings opened on the side surface of the pallet, and the insertion openings are made with these forks. It is necessary to reliably support a sufficient length range from the inside to the inner side. Therefore, in an unmanned forklift, as shown in FIG. 8 which schematically shows only the vicinity of the tip of the fork, an insertion port detection sensor for detecting the insertion port of the pallet at each tip of the forks 31, In other words, the optical sensor 32 that detects the insertion opening that is open between the upper and lower deck boards along the height (vertical) direction and the optical sensor 32 that connects the upper and lower deck boards are opened. A contact detection sensor 33 that detects the insertion port along the lateral (horizontal) direction is provided.

That is, at this time, at the tip end position of each fork 31, there is formed a concave portion 31a which is arranged along the longitudinal direction of the fork 31 itself and which opens downward, and the tip end opening in this concave portion 31a. An optical sensor 32 having a visual field outside the fork 31 along the longitudinal direction is provided on the side, and a microswitch that functions as a contact detection sensor 33 is provided on the rear end side of the optical sensor 32. . The downward opening surface of the concave portion 31a in which the optical sensor 32 and the contact detection sensor 33 are installed has a cross-sectional shape similar to the fork 31 and has an upward U-shape, and extends along the longitudinal direction of each fork 31. It is closed from the outside by a slidable contact member 34.

Further, the contact member 34 uses an elastic member (not shown) such as a spring, so that the contact member 34 slightly protrudes outward along the longitudinal direction of each fork 31 and then retracts. Is supported as a possible state. Therefore, when the pallet is scooped out, the contact member 34 protruding outward from the tip side along the longitudinal direction of each fork 31 moves backward as a result of contacting the pallet girder or the like, and the contact member 34 causes the contact detection sensor. Since the micro switch 33 is turned on, the pallet scooping work by the fork 31 is stopped.

[0006]

By the way, of the insertion port detection sensors provided in the conventional forklift,
The contact detection sensor 33, which is a micro switch, is turned on when the contact member 34 is retracted, but is configured to simply advance and retract along the longitudinal direction of the fork 31. Therefore, the contact member 34 that comes into contact with the girder of the pallet retracts immediately, even slightly, and the contact detection sensor 33 is turned on. Therefore, in the conventional forklift truck, the pallet scooping operation is often stopped, resulting in a reduction in workability.

The present invention was devised in view of such inconvenience, and the contact member does not retract at the position where it slightly contacts the pallet, and the difference between the pallets is provided as long as the contact is slight. An object of the present invention is to provide a contact detection sensor for a fork, which allows a fork to safely and surely enter the insertion opening and which is unlikely to cause a decrease in workability.

[0008]

A contact detecting sensor for a fork according to claim 1 of the present invention detects the contact between the fork and the pallet by detecting the movement of a contact member attached to the tip of the fork. The contact member is movably attached to the fork via an elastic member, and has a tapered surface narrowed toward the tip of the contact member.

A fork contact detection sensor according to a second aspect of the present invention is the one according to the first aspect, in which the base end portion of the fork has a supporting structure capable of allowing a slight positional deviation and is then lifted. It is characterized by being supported by a bracket.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view showing a simplified overall structure of a forklift, FIG. 2 is an enlarged top view showing only the vicinity of the tip of a fork, and FIG. 3 is a side view thereof.
FIG. 4 is a bottom view thereof. 5 is an exploded perspective view schematically showing the vicinity of the tip of the fork, FIG. 6 is an enlarged side view showing the vicinity of the base of the fork, and FIG. 7 is an explanatory view for explaining the displacement operation of the fork. Is. In these drawings, reference numeral 3 is a lift bracket, 4 is a fork, 12 is a contact detection sensor, and 13 is a contact member.

The forklift according to the present embodiment is
The vehicle body 1 includes an unmanned vehicle body 1 that is driven unattended by using magnetic induction, and as shown in FIG. 1, a pair of left and right masts 2 are provided upright at a front position of the vehicle body 1. The lift brackets 3 are moved up and down along the masts 2, and the lift brackets 3 are moved up and down while being guided by the masts 2.
Four forks 4 are supported. Further, a stabilizer 5 is arranged for the lift bracket 3, and the stabilizer 5 is placed on the fork 4 and supports a load (not shown) being transported by being sandwiched between the fork 4 and the fork 4. It functions as a clamp device.

In FIG. 1, the mast 2 of the forklift is a two-stage mast, that is, the outer (fixed).
The mast 2a and the inner (movable) mast 2b that moves up and down are described as a two-stage mast, but it goes without saying that the mast 2 included in the forklift to which the present invention is applied is not limited to the two-stage mast. Further, reference numeral 6 in FIG. 1 indicates a wireless antenna, and reference numeral 7 indicates a driver's seat, respectively. When unmanned driving becomes impossible, an operator sitting on the driver's seat 7 can operate the forklift. Has become.

On the other hand, at the tip positions of the forks 4 of the forklift, that is, the four forks 4 arranged in parallel with each other, as shown in FIGS. (Not shown) for detecting the insertion port, that is, the optical sensor 11 for detecting the insertion port of the pallet opened between the upper and lower deck boards along the height (vertical) direction, and the upper and lower surfaces. A contact detection sensor 12 for detecting an insertion opening opened between the girders connecting the deck boards along the lateral (horizontal) direction is arranged. The optical sensor 11 is similar to the optical sensor 32 according to the related art, and the contact detection sensor 12 detects the contact with the pallet via the contact member 13. The reference numeral 14 in FIGS. 2 to 4 is a protective plate, and the protective plate 14 is for protecting the optical sensor 11.

That is, as schematically shown in FIG.
At the respective tip positions of the forks 4 having a rectangular cross-section, a rectangular parallelepiped tip 4a having a smaller overall outer shape and a rectangular cross-section extends toward the outside along the longitudinal direction of the fork 4. The front end portion 4a is formed with a recess 4b having a predetermined depth and opening downward. An optical sensor 11 having a visual field outward along the longitudinal direction of the fork 4 is arranged on the tip opening side in the recess 4b, and is located in the recess 4b on the rear end side of the optical sensor 11. Is provided with a proximity switch that functions as the contact detection sensor 12.

Further, a contact member 13 having a rectangular tube structure, which surrounds the outer periphery of the tip 4a and is open at both ends, is fitted on the tip 4a of each of the forks 4. Is manufactured using a magnetic material such as a metal, for example, an iron material. That is, the contact member 13 includes an upper part 15 having a downward U-shape that covers the upper surface and both side surfaces of the tip 4 a of the fork 4, and a lower part 16 that closes the lower opening of the upper part 15. But,
It is integrated by using screws. Then, each surface of the contact member 13, that is, at least both side surfaces 15b of the upper part 15 in which the upper surface 4c of the fork 4 is flush with the upper surface 15a, both side surfaces 16a and the lower surface 16b of the lower part 16, respectively. Is a tapered surface inclined at a predetermined angle so as to become thinner toward the outside along the longitudinal direction of the fork 4, in other words, toward the tip of the contact member 13.

In this embodiment, both side surfaces 15b of the upper part 15 and both side surfaces 16a and the lower surface 16b of the lower part 16 are tapered surfaces.
The upper surface 15a may also be a tapered surface. Further, in this case, the upper part 15 has a downward U-shape, and the lower part 16 closes the lower opening of the upper part 15. However, the lower part 16 has an upward U-shape. Of course, the upper part 15 may be configured to close the upper opening of the lower part 16. Alternatively, the upper part 1
5 and the lower part 16 have a similar U-shape, and the contact member 13 may be integrated by aligning these on the side surface of the fork 4 from above and below.

Further, in the vicinity of the substantially central position of the lower part 16 constituting the contact member 13, a rectangular switch for exposing the proximity switch which is the contact detection sensor 12 attached to the tip 4a of the fork 4 is exposed. An opening 17 having a shape is formed, and the contact detection sensor 12, which is a proximity switch, is attached to the tip 4 a so as to face the opening 17 of the contact member 13. Furthermore, the contact member 13 is internally fitted to both sides of the upper part 15 thereof, and the sensitivity of the contact is adjusted, that is, after the pair of left and right coil springs, which are elastic members 18 whose reaction forces are adjusted, are interposed therebetween. 4 is attached to the end face of the fork 4, and the contact member 13 is supported by being protruded outward along the longitudinal direction of the fork 4 via these elastic members 18. That is, the contact member 13 here is attached to the tip of the fork via the elastic member 18 so as to be movable back and forth.

Each of the forks 4 included in the forklift according to the present embodiment has an optical sensor 11 for detecting a fork insertion opening through a detection hole 23 and a contact member 1.
An insertion port detection sensor including a contact detection sensor 12 that is a proximity switch that detects contact with the pallet via the contact point 3 is provided. In the scooping work of the pallet with the fork 4, these two types of detection sensors 11,
Using fork 12, each of the forks 4 arranged in parallel can be safely and surely inserted into the insertion port of the pallet.

Assuming that the contact member 13 protruding outward from the tip end along the longitudinal direction of each of the forks 4 comes into direct contact with the girder of the pallet or the like from the front, the contact member 13 is an elastic member 18. As the coil spring retreats while resisting the elastic force of the coil spring, the magnetic material portion around the opening 17 of the contact member 13 is detected by the proximity switch as the contact detection sensor 12, and this proximity switch is turned on.
As a result of the operation, the scooping work of the pallet by the fork 4 is stopped.

However, in the case where the contact with the girders of the pallet or the like is not a direct contact from the front but only a slight contact, the contact member 13 has any one of its surfaces, that is, both side surfaces 15b of the upper part 15. Also, since either of the side surfaces 16a of the lower part 16 and the taper surface of the lower surface 16b proceed along the contacting object such as the girder of the pallet, the force at the time of inserting the fork 4 is released, and it always moves backward. Not surprisingly, it is inserted into the insertion slot of the pallet. In such a case, as a result of each of the forks 4 being inserted from the insertion port of the pallet to the inner rear side while being guided by the contact member 13, the pallet scooping work by the fork 4 is not stopped. , You can continue as it is. Therefore, with the forklift according to the present embodiment, the frequency of stopping the pallet scooping operation is reduced.

Furthermore, in the forklift according to the present embodiment, it is preferable that the base end portion 4d of each fork 4 supported by the lift bracket 3 has a supporting structure capable of allowing a slight displacement. That is, as shown in FIG. 6, the base end portion 4d of each fork 4 is attached to the lift bracket 3 via the support pin 19, and a hole formed in the fork 4 and through which the support pin 19 penetrates. If the diameter of 20 is set to be slightly larger than the diameter of the support pin 19, the base end portion 4d of the fork 4 can be displaced based on the difference in diameter, that is, it can be displaced at least along the left-right direction. It becomes possible to do.

In the case of such a structure,
Contact member 13 in a state of slightly contacting the pallet girder
Is advanced into the insertion slot of the pallet, a force for displacing the fork 4 in the left-right direction is applied by the tapered surface of the contact member 13, and as a result, as shown in FIGS. 7 (a) and 7 (b). 4 is displaced in the left-right direction, that is, the fork 4 swings or moves laterally, so that each of the forks 4 is securely inserted into the inner side of the pallet as the contact member 13 guides. Will be done.
Reference numeral 21 in FIG. 6 indicates a stopper, which is necessary for horizontally supporting the fork 4 whose base end portion 4d is non-fixedly supported by the lift bracket 3.
Is attached to a predetermined height position on the lift bracket 3.

In the present embodiment, the contact member 13 is movable back and forth, but as another example, it may be movable in all front, rear, left and right directions, and it is possible to cope with such a moving direction. You may provide the sensor to operate. Also,
In this embodiment, it is assumed that the forklift including the contact detection sensors 12 for detecting the contact with the pallet via the contact member 13 arranged on each of the plurality of forks 4 is operated unattended by using magnetic induction or the like. However, the present invention is not limited to the unmanned operation, but the present invention can be applied to a forklift manually operated by an operator, that is, a manned operation.

Further, the elastic member 13 is not limited to the coil spring, and for example, the elastic member 13 made of rubber or the like, that is, the force applied to the contact member 13 when the fork 4 is inserted is small. , Contact member 1
3 is not allowed, and if it is more than a predetermined size,
It goes without saying that it may be selected from various members that allow the movement of the contact member 13.

[0025]

As described above, in the invention according to claim 1, the contact member at the tip of the fork has a tapered surface and is movably supported by the fork via the elastic member. ing. Therefore, when the contact member contacts the girder of the pallet only slightly, the tapered surface of the contact member advances along the contact object such as the girder of the pallet. It will be inserted into the outlet. Therefore, the contact member does not move at the position where it is slightly contacted with the pallet, and as long as the contact force is a little when the contact force is smaller than the reaction force of the elastic member, the fork can be safely inserted into the pallet insertion port. As a result, it is possible to surely make the entry, and it is possible to obtain the effect that it is unlikely that the workability is deteriorated.

Further, in the invention according to claim 2, since the base end portion of the fork has a support structure capable of permitting positional displacement, the pallet is inserted with the contact member slightly contacting the pallet girder or the like. When it moves into the mouth, it is moved into the insertion opening of the pallet due to the displacement of the fork in the left-right direction, and the advantage that each of these forks is surely inserted into the inner depth side of the pallet is secured.

[Brief description of drawings]

FIG. 1 is a side view showing a simplified overall structure of a forklift truck.

FIG. 2 is an enlarged top view showing the vicinity of the tip of the fork.

FIG. 3 is a side view thereof.

FIG. 4 is a bottom view thereof.

FIG. 5 is an exploded perspective view schematically showing the vicinity of the tip of the fork.

FIG. 6 is an enlarged side view showing the vicinity of a base end portion of a fork.

FIG. 7 is an explanatory diagram illustrating a displacement operation of a fork.

FIG. 8 is a partially cutaway perspective view schematically showing the vicinity of a tip end portion of a fork according to a conventional form.

[Explanation of symbols]

3 lift bracket 4 forks 4a Tip of fork 4d Fork base 12 Proximity switch (contact detection sensor) 13 Contact member 15 Upper part 15a Upper surface of upper part (tapered surface) 15b Side surface of upper part (tapered surface) 16 Lower part 16a Side surface of lower part (tapered surface) 16b Lower surface of lower part (tapered surface) 17 openings 18 Coil spring (elastic member)

Claims (2)

[Claims] 1. A fork contact detection sensor for detecting contact between a fork and a pallet by detecting movement of a contact member attached to the tip of the fork, wherein the contact member is an elastic member with respect to the fork. A contact detection sensor for a fork, wherein the contact detection sensor is mounted so as to be movable through the contact member and has a tapered surface that is narrowed toward the tip of the contact member. 2. The contact detection sensor for a fork according to claim 1, wherein the base end of the fork has a support structure capable of allowing a slight displacement and is supported by a lift bracket. .