JP2013018610A - Hand-operated lifter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hand-operated lifter having a motor which is driven according to strain applied in a handle, while preventing a load cell from being strained to drive a front wheel when the handle is depressed for pressing down a lifted rear wheel.SOLUTION: The hand-operated lifter includes a non-grounded state detecting means 10 detecting that the rear wheel 6 is in a non-grounded state or becomes the same state as the non-grounded state. The hand-operated lifter performs control so as to invalidate operation for driving a front wheel 4L by a handle 7 when the non-grounded state detecting means 10 operates.

Description

  The present invention relates to a lifter in a hand travel form, and travels while driving a front wheel by detecting a bending operation force of a handle with a load cell.

  Conventionally, there are various hand travel type lifters, and Japanese Patent Application Laid-Open No. 2004-151561 describes that a vehicle can travel by detecting a bending operation force of a handle with a load cell and driving a front wheel.

JP 2010-269903 A

The hand lifter that drives the front wheel by driving the front wheel by gripping the handle from the back of the traveling aircraft and bending the handle in the front-rear direction can move forward, and if it is pulled backward, it can move backward. Yes, it is controlled to stop running when the hand is released from the handle. For example, when trying to lift a load that exceeds the limit by this operation method, when the load is lifted with the center of gravity of the load being offset toward the front end of the lift fork, or in the forward running state with the front center of gravity It is conceivable that the rear caster wheel is lifted off the ground when it stops from the ground, and is in a non-grounded state, but its safety measure is not yet supported. When the caster wheel is lifted, the operator rushes and presses the handle from above in order to prevent the lifter from overturning. Since the operation is the same as the steering wheel operation, the front wheel is driven in the backward direction so that the lifter falls further forward, which is very dangerous.
An object of the present invention is to provide a safe hand travel lifter in which a front wheel is not driven even when a rear caster wheel is lifted and a driver presses a handle.

 A pair of left and right drive front wheels 4L, 4R are provided on both the left and right sides of the front part of the traveling machine body 3 in which the lift mast 2 for raising and lowering the lift fork 1 is installed, and the rear bottom part of the traveling machine body 3 is freely steerable. A wheel 6 is provided, a handle 7 is provided behind the lift mast 2, and an operating force generated by the operator holding the handle 7 and bending in the front-rear direction while walking behind the traveling machine body 3 is applied to the load cell 8L. , 8R, and a pair of left and right motors 9L, 9R, each of the front wheels 4L, 4R can be driven forward, reverse, or driven to rotate according to the operating force. A non-grounding detection means 10 for detecting that the rear wheel 6 is in a non-grounding state or a state similar to the non-grounding state is provided, and when the non-grounding detection means 10 is operated, 7 operations Front wheels 4L, the controlling hand traveling lifter comprising configured to disable the 4R driving operation by.

  Further, when the rear wheel 6 is in the non-grounded state or the same state as the non-grounded state continues for a predetermined time T or longer, the hand traveling is controlled so as to invalidate the driving operation of the front wheels 4L and 4R by the steering wheel 7 operation. The lifter configuration.

  The invention according to claim 1 is a non-grounding detection for detecting that the rear wheel 6 provided on the rear bottom portion of the traveling machine body 3 is in a non-grounding surface state or a state similar to the non-grounding state. When the non-grounding detection means 10 is operated, the front wheel 4L, 4R driving operation by the operation of the handle 7 is controlled to be invalidated. Even when the steering wheel 7 is operated so as to hold down the rear wheel 6 when it is in an unstable state, the front wheels 4L and 4R are safe.

  According to the second aspect of the present invention, when the rear wheel 6 is not in contact with the ground for a predetermined time T or longer, the front wheel 4L, 4R drive operation by the operation of the handle 7 is controlled to be invalidated. Even if the rear wheel 6 becomes ungrounded for a moment due to a road surface step or the like, the running state can be continued without stopping, and stable running can be achieved, and the rear wheel can continue for a predetermined time T or longer. The driving operation of the front wheels 4L and 4R by the operation of the handle 7 can be surely invalidated in a dangerous state in which 6 is in a non-grounding state.

The partial cutaway side view of a hand drive lifter. The cut-away side view which shows the operation state of a non-grounding detection means. The block diagram of driving operation. The rear view of a hand drive lifter. The side view of a hand drive lifter. The top view of a hand drive lifter.

  The hand travel lifter of the present invention is provided with a lift fork 1 that is guided up and down along a lift mast 2 erected from a traveling machine body 3, and a traveling frame that protrudes forward from both left and right ends of the traveling machine body 3. Front wheels 4L and 4R for driving are provided at the front end portion of 15, and a pair of left and right caster wheels 6 are provided at the rear bottom of the traveling machine body 3. Above the traveling body 3 behind the lift mast 2, a handle 7 having a T-shape in plan view that can be gripped by the operator with left and right hands is provided, and gripping portions 16 </ b> L and 16 </ b> R projecting in the left-right direction of the handle 7 are provided. The load cells 8L and 8R are provided. The load cells 8L and 8R detect the operation force for the operator to hold the left and right handles 7 and bend them in the front-rear direction, and the load cells 8L and 8R are provided in the traveling machine body 3 according to the operation force. The pair of left and right motors 9L and 9R are driven, and this driving force is configured to assist the front wheels 4L and 4R via the chains 17 and 18 and the sprocket 19 and the like. The hand travel lifter in the present embodiment is described as an example of a reach type in which the travel frame 15 protrudes forward, but is not limited to the reach type, and the front wheels 4L and 4R of the lift mast 2 in a side view are shown. It may be a counter type lifter provided at a lower position and protruding only the lift fork 1 forward without protruding the traveling frame 15 forward.

  The traveling machine body 3 is provided with motors 9L and 9R for driving the front wheels 4L and 4R, a controller 26, a battery 27, a charger 35, a hydraulic pump unit 28 for lifting and lowering the lift fork 1 and the like. It is covered. A cylinder 30 provided at the center of the lift mast 2 is for lifting and lowering the lift fork 1, and the lift fork 1 can be lifted and lowered by operating a lift lever 31 of the hydraulic pump unit 28. A display panel 32, a power switch 33, and an emergency stop button 34 are provided on the rear upper part of the body cover 29 to display the remaining amount of the battery 27, the abnormality of the body, and the like.

  First, normal operation of the steering wheel lifter according to the present invention will be described. When the power switch 33 is turned ON and the operator standing on the rear side of the aircraft grips the left and right gripping portions 16L and 16R with both hands and bends the gripping portions 16L and 16R in the front-rear direction, this operating force is applied to the load cells 8L and 8R. Is detected, and the left and right motors 9L and 9R and the front wheels 4L and 4R can be driven to travel. At this time, when the left and right front wheels 4L and 4R rotate in the same direction, the vehicle can travel straight, and when there is a difference in rotation between the left and right front wheels 4L and 4R, the vehicle turns to a lower rotation side. Further, when one of the left and right grips 16L and 16R is operated toward the front and the other toward the rear, the left and right grips 16L and 16R can be turned on the spot. It is possible to travel by operating the handle 7 to insert the lift fork 1 into the pallet 36 and to operate the lifting lever 31 to pick up and carry the luggage 37. The load cells 8L and 8R can control the motors 9L and 9R output with an output according to the operation force. When a large operation force is applied to the load cells 8L and 8R, the motors 9L and 9R rotate at high speed, This lifter is an assist drive type that stops if no operating force is applied.

  FIG. 3 is a schematic block diagram showing the present invention. The load cells 8L and 8R detect the bending operation force applied to the gripping portions 16L and 16R of the left and right hands of the operator, and outputs corresponding to the detected values. The controller 26 outputs to the motors 9L and 9R. The rotational drive of the motors 9L and 9R is transmitted to the front wheels 4L and 4R via the reduction gears, chains 17 and 18, the sprocket 19 and the like, and is provided in the motors 9L and 9R when the bending operation force to the gripping portions 16L and 16R is lost. Then, the electromagnetic brakes 38L and 38R are operated and stopped.

  Between the pair of left and right rear wheels 6 and the rear wheel 6, the rear wheels 6, 6 are in a non-grounded state and are lifted up, or are in the same state as the state in which the rear wheel 6 is lifted up Non-grounding detection means 10 for detection is provided. Here, a non-grounding detection means 10 for detecting that the rear wheel 6 is in a non-grounding state or a state similar to the non-grounding state is provided, and the non-grounding detection means 10 is activated. Is a configuration of a hand travel lifter that is controlled to invalidate the front wheel 4L, 4R drive operation by the steering wheel 7 operation.

  FIG. 2 shows an example of the non-grounding detection means 10. FIG. 2 (a) shows a state where both the rear wheel 6 and the wheel 22 are in a grounded state, and FIG. This shows a case where the grounding state is reached. A wheel 22 having a caster angle is provided below the shaft 21 into which the inside of the boss 20 provided on the traveling machine body 3 is inserted, and the wheel 22 and the shaft 21 are urged downward by a compression spring 23. The boss 20 is provided with a hexagonal hole, and a hexagonal shaft 21 is inserted into the hole to allow the shaft 21 to move only in the vertical direction. A limit plate 24 is provided above the shaft 21, and a limit switch 25 that is turned on and off as the limit plate 24 moves up and down is provided. With this configuration, when the rear wheel 6 that is normally grounded is lifted, the wheel 22 moves downward together with the shaft 21 and the limit plate 24 by the urging force of the spring 23, and the limit switch 25 is turned off. It becomes a state. The limit switch 25 OFF signal is input to the controller 26, the operation of the load cells 8L and 8R is invalidated, and the motors 9L and 9R are not driven even if the load cells 8L and 8R detect distortion. Therefore, when the rear wheel 6 is lifted and is not in contact with the ground, even if the driver suddenly presses the handle 7 so as to press the lift and the load cells 8L and 8R are distorted, the motors 9L and 9R are caused by the distortion. No driving signal is output, and the front wheels 4L and 4R are safe because they are not driven and rotated. Note that the non-grounding detection means 10 in the example does not detect that the rear wheel 6 has lifted up, but detects that the rear wheel 6 has been lifted. The non-grounding detecting means 10 can be provided on the rear wheel 6 itself.

  Once this non-grounding detection means 10 is activated, the driving of the motors 9L and 9R is disabled until the rear wheel 6 is ungrounded, the rear wheel 6 is grounded, and there is a risk of falling or the like. If the vehicle is in a safe state with no running, normal driving is possible. Accordingly, after picking up the luggage, when the lift fork 1 is slightly lifted, the rear wheel 6 is lifted when the forward fork is suddenly stopped or the center of gravity of the luggage is on the front end side of the lift fork 1, etc. Even when the lift fork 1 or the front end of the luggage 37 is in a grounded state and the rear wheel 6 is in a lifted state, the operation becomes invalid even if the gripping portions 16L, 16R are operated, and the front wheels 4L, 4R is not driven. At this time, if the lifting / lowering lever 31 is operated to lower the lift fork 1 to release the operation of the non-grounding detecting means 10, a normal traveling operation can be performed.

  Even when running on a flat road surface, the non-contact detection means 10 may be activated due to slight steps or unevenness on the road surface, and the driver is completely conscious when there is no danger of falling or the like. When the vehicle is not in a state where the aircraft is running, this is very annoying, so the hand travel lifter of the present invention is provided with a timer (not shown) and the rear wheel 6 is lifted, or Control is performed so as to invalidate the operation of the gripping portions 16L and 16R when the same state as the floating state continues for a predetermined time T or longer. As a result, when the rear wheel 6 is lifted in a state where there is a risk of falling or the like, the driving of the front wheels 4L and 4R by the operation of the handle 7 is surely invalidated and a little in the state where there is no risk of falling or the like. The non-grounding detection means 10 does not operate due to a step or unevenness of the road surface, and a smooth transportation operation can be continued.

DESCRIPTION OF SYMBOLS 1 Lift fork 2 Lift mast 3 Traveling machine body 4L Front wheel 4R Front wheel 6 Rear wheel 7 Handle 8L Load cell 8R Load cell 9L Motor 9R Motor 10 Non-grounding detection means T Predetermined time

Claims (2)

  A pair of left and right driving front wheels (4L) and (4R) are provided on the left and right sides of the front part of the traveling machine body (3) provided with a lift mast (2) for raising and lowering the lift fork (1), and the traveling machine body (3 ) A steerable rear wheel (6) is provided at the bottom of the rear side, a handle (7) is provided behind the lift mast (2), and the operator walks behind the traveling machine body (3). , The operation force generated by holding the handle (7) and bending it in the front-rear direction is detected by the load cells (8L), (8R), and the front wheels (4L) are connected via the left and right motors (9L), (9R). , (4R) each of the rear wheels (6) is in a non-grounded state in a hand travel lifter capable of traveling by driving forward, reverse, or driving rotation according to the operating force, or , Ungrounded to detect that it is in the same state as ungrounded state When the non-grounding detection means (10) is actuated by the knowledge means (10), the hand travel lifter is controlled so as to invalidate the front wheel (4L) and (4R) drive operations by operating the handle (7). .   The front wheel (4L) and (4R) drive operations are invalidated by operating the steering wheel (7) when the rear wheel (6) is not grounded or is in a state similar to the non-grounded state for a predetermined time (T) or longer. The hand travel lifter according to claim 1, wherein the hand travel lifter is controlled to be controlled.

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