JPS5940758B2 - Forklift push pull attachment - Google Patents

Description

Detailed Description of the Invention The present invention relates to a push-pull attachment for a forklift.More specifically, this invention relates to a push-pull attachment for a forklift. Attachments are provided.

One type of cargo handling by forklift trucks is the use of thin flexible pallets (for example, pallets made of cardboard membrane).

From now on, it is called sheet pallet. ) The cargo stacked on top of the seat pallet is grasped by a gripper that can move forward and backward at one end of the sheet pallet, and the cargo is loaded by pulling it onto the fork, and after being transported, the cargo is pushed out by a push plate. How to lower it (this device is called a push-pull attachment).

). In cargo handling operations using this push-pull attachment, when unloading cargo, it may be necessary to push out only the cargo without pushing out the sheet pallet together with the cargo.

Push-pull attachments that can perform this kind of work have been known for some time, but they were not satisfactory because they were cumbersome to operate and there was a risk of the load collapsing due to incorrect operation.

A more detailed explanation will be given based on a drawing showing an example of a conventional device.

In Figures 1 to 3, a base frame 2 is attached to a bracket 1 that is movably mounted on an oak lift truck, and a fork (in this example, a wide one Plate 3) is installed.

A subframe 5 is also fitted to the base frame 2 and is moved up and down by a clamp cylinder 4.
A clamp bar 6 is fixed to the lower part of the subframe 5.

A bushing plate 11 is attached to the front surface of the subframe 5 and is moved forward and backward by reach cylinders 9 and 10 via a pantograph 7.8.

At the bottom of the bushing plate 11 is a grip cylinder 12.
．． A gripper 14 which is operated to open and close by 13 is attached.

Further, FIG. 4 shows the hydraulic circuit of the device.

In the figure, 15 is a sequence pulp, 16 and 17 are switching pulps, and 18 and 19 are operating levers.

Next, a method of pushing out only the baggage 21 while leaving the sheet pallet 20 on the oak 3 using the conventional device will be explained based on FIGS.

As shown in FIG. 5, the end 20a of the sheet pallet 20
Grip it with the gripper 14 and pull the load 21 onto the fork 3. When the gripper 14 comes to the position directly above the clamp bar 6, turn the operating lever 18 in the opposite direction (towards the forward direction of the bushing plate 11) for a short time. Then, the flow of hydraulic oil is reversed and the hydraulic oil is supplied to the rod side of the Jigrip cylinders 12 and 13, and the gripper 14 opens (.

Subsequently, when the operating lever 19 is operated to supply hydraulic oil to the piston side of the clamp cylinder, the subframe 5 is raised, and the gripper 14 and the clamp bar 6 are also raised together.

Therefore, as shown in FIG. 6, the end 20a of the sheet pallet 20 rotates downward due to its own elasticity and
It enters the gap between the clamp bar 6 and the fork 3.

Next, when the subframe 5 is lowered by operating the operating lever 19, the end portion 20a of the sheet pallet is clamped by the clamp bar 6 and the fork 3 as shown in FIG. If the bushing plate 11 is advanced by
remains on the fork 3, and only the load 21 is pushed out.

Although this conventional device is very convenient, it has the following drawbacks.

(i) There are only two operating levers, making operation cumbersome.

(i) Considerable care and skill are required to operate the operating lever 18 to open the gripper 14.

If the operation is too fast (if the time for operating the operating bar 18 in the opposite direction is too short), the gripper 14 will not be opened sufficiently, and if it is too slow, the gripper 14 will open to the maximum and the sequence pulp 15 will operate. This is because the reach cylinders 9 and 10 advance the bushing plate 11 and push out the sheet pallet 20 along with the cargo 21.

This operation is particularly difficult due to the small stroke of the grip cylinders 12,13.

@) If you forget to operate the operating lever 18 and operate the operating lever 19 while holding the sheet pallet 20 in the gripper 14, there is a risk that the cargo will collapse.

This is because the sheet pallet 20 (underneath the sheet pallet 21) will be pulled up, and the risk of this is actually high.

This invention was made with the aim of eliminating the above-mentioned drawbacks of conventional devices, and its gist is to provide a structure that is movable back and forth on a fork attached to the front side of a forklift truck; a gripper that is attached to the lower part of the structure and grips the end of the sheet pallet laid under the cargo; and a clamp means that fixes the sheet pallet to the end of the sheet pallet at a certain longitudinal position on the fork. , a reach cylinder for actuating the structure, the gripper and the clamping means, respectively;
In a push-pull attachment comprising a grip cylinder and a clamp cylinder, a reach cylinder passageway in which the supply direction of pressure oil is switched by a first switching valve that is connected to the reach cylinder via a sequence pulp and operated by an operating lever. A grip cylinder passage and a clamp cylinder passage are branched from the part between the first switching valve and the sequence pulp and connected to the grip cylinder and clamp cylinder respectively, and the grip cylinder passage and the clamp cylinder passage are connected to each other. The supply direction of pressure oil is switched to the direction in which the grip cylinder is operated so as to cause the gripper to grip the sheet pallet, and the flow of pressure oil is blocked in the direction in which the clamp cylinder is operated so as to cause the clamping means to release the clamp of the sheet pallet. Switching between a first state in which the check valve is interposed in the clamp cylinder passage and a second state in which the supply direction of pressure oil in the grip cylinder passage is reversed from the first state and in which the check valve is not interposed in the clamp cylinder passage. a second switching pulp capable of
- state can be switched to a second state.

Hereinafter, one embodiment of the present invention will be described in detail based on FIGS. 8 to 11 showing various operating modes.

In the figure, reach cylinders 9, 10 . Grip cylinders 12, 13. The sequence valve 15 is the same as the conventional device and is given the same reference numeral.

In the naori lamp cylinder 4', the entire push-pull device is suspended by a piston rod, contrary to the conventional device.

It is installed so that it can be raised.

Also, pantograph 7.8. Gripper 14. The clamp bar 6 and the like may be similar to those of the conventional device, but are of course not limited to these (any material that can perform the same function as these can be used in the present invention). be.

A reach cylinder passage consisting of pipes 31, 32, 39, 40, 41, and 42 is connected to the reach cylinder 9 (the same applies to the reach cylinder 10), and a sequencer 1 Subaru 15 is connected to the reach cylinder passage in the middle of this reach cylinder passage. The reach cylinder 9 is supplied with pressure oil only when the oil pressure of the pressure oil supplied to the reach cylinder passage exceeds a set value.

The pipes 31 and 32 are connected to a switching pulp (not shown), and the switching pulp is operated.

The supply direction of pressure oil to the seal cylinder passage can be changed by switching by operating a lever.

A grip cylinder passage consisting of conduits 33, 34, 35 and 36 is branched from the reach cylinder passage.
(also connected to).

Further from the reach cylinder passage are pipes 33, 37 and 3.
The clamp cylinder channel 8 is also branched off and connected to the clamp cylinder 4.

A mechanical switching valve (hereinafter referred to as a selector pulp) is provided in the middle of these grip cylinder passages and clamp cylinder passages, and this selector pulp 30 is fixed to the subframe 5.

The selector pulp 30 is always in the first state shown in FIG. It is possible to switch to the second state shown in FIG.

In the first state, the supply direction of pressure oil in the grip cylinder passage is switched to the direction in which the grip cylinder 12 is actuated so that the gripper 14 grips the sheet pallet 20, and the check valve 30av is interposed in the clamp cylinder passage, and the clamp bar is The second state is a state in which the flow of pressure oil in the direction in which the clamp cylinder 4 is operated so as to release the clamp of the sheet pallet 20 in the second state is the first state. is reversed, and a check valve 30 is installed in the clamp cylinder passage.
a& without intervention.

Note that the grip cylinder passage and the clamp cylinder passage are branched from the reach cylinder passage on the subframe 5, so there are only two reciprocating hoses to be hung on the mast to supply pressure oil to the entire push-pull attachment. It has four legs (the conventional system had four) and a wide field of view for the driver, making it easier to carry out cargo handling operations.

Next, the operation will be explained.

In FIG. 8, the bushing plate 11 is in the forwardly pushed position, the selector pulp 30 is in the first position, the switching pulp (male shown) is switched by the operation lever, and the pipe line 31 is connected to the pump P. , the pipe line 32 is connected to the tank T (both not shown).

) respectively connected to one hydraulic oil pipe 33.). The grip cylinder 12 via the selector pulp 30 and the conduit 35.
After the gripper 14 grips the seat harness 20, the sequence valve 15 is actuated, and the oil is supplied to the reach cylinders 9, 10 via the hydraulic oil pipes 40 and 41, and the bush plate 11 is moved by the pantograph 7.8.
shows a state in which the gripper 14 has started retracting the load.

Note that since the selector pulp 30 is provided with a check valve 30a, hydraulic oil is not supplied to the pipe line 37, and the crank cylinder 4' does not operate.

When the load is sufficiently pulled in, as shown in FIG. (Although it is of course possible to reverse the mounting positions of the selector pulp 30 and the contact body 43, this embodiment has the advantage that the piping is easier.

) Selector pulp 30 is switched to the second state.

Hydraulic oil is therefore supplied via lines 31, 33v, respectively, from line 37 to clamp cylinder 4' and from line 36 to grip cylinder 12,13.

However, since the weight of the push-pull device is on the clamp cylinder 4', the grip cylinder 12.13
The clamp cylinder 4' does not operate until the clamp cylinder 4' completes its operation.

Hence Grino? There is no longer any possibility of the sheet pallet 20 being lifted up with the door 14 closed, and there is no danger of the cargo collapsing due to the sheet pallet 20 being hoisted up.

FIG. 10 shows that when the end 20a of the sheet pallet 20 comes off the gripper 14 and enters the gap between the clamp bar 6 and the fork 3, the switching valve is switched by the operating lever, and the pipe line 32 is connected to the pump P. The lines 31 are shown connected to the tanks T, respectively.

Hydraulic oil is supplied to the clamp cylinder 4' through pipes 32, 39, and 38, the subframe 5 is lowered, and the seat pallet 20 is placed between the lower surface of the clamp bar 6 and the upper surface of the fork 3.
The end portion 20a of is in a clamped state.

Subsequently, sequence valve 15 is activated, and line 39. Sequence valve 15. Reach cylinder 9 via conduit 42,
Hydraulic oil is supplied to 10, and only the cargo is pushed out by bush plate 11.

At this time, hydraulic oil is also supplied to the grip cylinders 12 and 13, and the gripper 14 closes, but the sheet pallet 20
has already come off the gripper 14, so there is no problem.

FIG. 11 shows a state in which the bushing plate 11 has moved forward a little while pushing the load.

When the contact 30b of the selector pulp 30 separates from the contact body 43, the selector valve 30 is automatically switched.

Therefore, the hydraulic oil passes through the pipe 36 to the grip cylinder 1.
2.13 is supplied, and the gripper 14 is opened (.

However, the clamp cylinder 4' continues to clamp the sheet pallet 20, and the reach cylinders 9, 1
0, the bushing plate 11 continues to operate in the direction of pushing out the load.

Eventually, the cargo is unloaded from the fork 3 and the sheet pallet 20 is removed, and preparations for the next cargo handling operation are completed.

By repeating the above operations, it is possible to transport the cargo stacked on the sheet pallet to the destination using a forklift, leave the sheet pallet on the 7 oak, unload only the cargo, and collect the sheet pallet. be.

Incidentally, it is also possible to unload the luggage together with the sheet pallet 20 using the apparatus of the embodiment.

That is, when retracting the bushing plate 11, if the load is stopped before the contact 30b of the selector pulp 30 contacts the abutting body 43 and the cargo is transported, and the switching valve is switched by the operating lever at the destination, Clamp cylinder 4' will not operate (.

grip cylinder 12.13 and reach cylinder 9,
10 is activated and the load is pushed out and lowered together with the sheet pallet 20.

However, in order to reduce the moment exerted on the front wheel shaft of the vehicle due to the weight of the cargo, it is desirable to load the cargo as deep as possible into the fork 3.

Therefore, it is effective to prevent the selector pulp 30 from operating even when the flush plate 11 is retracted to the stroke end.

Two embodiments of the apparatus that can achieve the above object are shown below.

FIG. 12 shows a movable contact body 43 that contacts the contact 30b of the selector pulp 30 to operate the selector pulp 30.

The movable abutment body 43' is pivotally connected to a member 44 fixed to the bushing plate 11, and is rotated to the positions indicated by the solid line and the two-dot chain line in the figure to activate or deactivate the selector pulp 30. selectively determine.

Note that the specific means for making the contact body movable is of course not limited to this.

FIG. 13 shows another embodiment in which activation/inactivation of the selector pulp 30 is selectively determined.

This uses the selector pulp 30 as an electromagnetic valve 30', and the operation of the electromagnetic valve 30' is controlled by a limit switch 45.

The limit switch 45 is activated when the bushing plate 11 is retracted to the stroke end, and when the electromagnetic valve 30' is made to perform the same action as in the previous embodiment, the 4ff is connected to the coil of the electromagnetic pulp 30', the limit switch 45, and the power source. This manual switch is connected in series to the series circuit with 47, and is installed near the driver's seat, and serves as a means for selecting whether the electromagnetic pulp 30 is activated or deactivated according to the driver's will.

In addition, although the selector pulp 30 was used in all of the above embodiments as a means for switching the hydraulic lines to the grip cylinders 12, 13 and the clamp cylinder 4', the present invention is not limited to this, and the means shown in FIG. As shown, similar effects can be achieved using conventional switching pulp and check valves.

The effects of the present invention are as follows.

(i) 1 for operating the first switching pulp in which the operating lever switches the supply direction of pressure oil in the reach cylinder passage;
It only requires a book and is easy to operate.

(i) Unlike conventional devices, delicate lever operations of the grip cylinder with a small stroke are not required, and the operation is easy.

(i) Since the clamp cylinder is configured so that it does not operate unless the gripper is completely opened, there is no risk of the load collapsing due to pulling up the sheet pallet due to incorrect operation.

[Brief explanation of drawings]

Figure 1 is a side view of the mechanical part of a conventional push-pull attachment, Figure 2 is the same (front view (partially cut away)), Figure 3 is the same (a plan view of the main parts, Figure 4 is a side view of the mechanical part of a conventional push-pull attachment), Hydraulic circuit diagram of the attachment. Figures 5 to 7 are side views showing the operating mode of the main parts of the device shown in Figure 1. Figures 8 to 11 are push-pull attachments according to the present invention. FIG. 12 is a side sectional view of means for selectively determining the operation of the selector pulp, and FIG. 13 is another means for selectively determining the operation of the selector valve. Electrical circuit diagram showing, No. 14
This figure is a hydraulic circuit diagram showing a circuit that can obtain the same effect as the selector pulp shown in FIGS. 8 to 13. 3: Fork, 4.4': Clamp cylinder, 5: Saku frame, 6: Clamp bar, 7.8: Pantograph,
s, io nirichulinda, 11:). spring), 12, 13 Nigelip cylinder, 14
Nigelitsupa, 15 Nijikensparu 1.20: Seat pallet), 30.30': Selector valve, 43.43'
: Abutting body.

Claims (1)

[Scope of Claims] 1. A structure that is movable back and forth on forks that are attached to the front side of a forklift truck, and an end portion of a sheet pallet that is attached to the lower part of the structure and placed under cargo. a gripper for gripping the fork, a clamping means for fixing the end of the sheet pallet to the fork at a predetermined longitudinal position on the fork, and a reach cylinder and a grip cylinder for operating these structures, the gripper, and the clamping means, respectively. and a clamp cylinder, the reach cylinder passage having a first switching pulp connected to the reach cylinder via a sequence pulp and having a pressure oil supply direction switched by a first switching pulp operated by an operating lever. - A grip cylinder passage and a clamp cylinder passage are branched from a portion between the switching pulp and the sequence pulp and connected to the grip cylinder and the clamp cylinder, respectively, and the grip cylinder passage and the clamp cylinder passage are connected to the grip cylinder passage and the clamp cylinder passage. Switching the supply direction of pressure oil in the passageway to a direction in which the grip cylinder is actuated so as to cause the gripper to grip the sheet pallet, and a direction in which the clamp cylinder is actuated so as to cause the clamping means to release the clamp on the sheet pallet. A first state in which a check valve for blocking the flow of pressure oil is interposed in the clamp cylinder passage, and a first state in which the supply direction of pressure oil in the grip cylinder passage is reversed from the first state and a check valve is provided in the clamp cylinder passage. A second switching pulp capable of switching to a second state without intervening a check valve is provided, and the second switching pulp switches from the first state to the above based on reaching the rear stroke end of the structure. A push-pull attachment for a forklift, characterized in that it can be switched to a second state.