JPH0840132A - Tail gate lifter - Google Patents

Abstract

PURPOSE:To easily project and store a caster stopper by providing a second elastic means to pressurize the caster stopper on a projecting position with a larger force than a first elastic means at the time when the caster stopper provided on a recessed part on a platform surface takes a storage position and a selector means to select whether to apply the force or not. CONSTITUTION:A caster stopper 2 is axially supported in a recessed part 3 of a platform 1. At the time of unloading, the caster stopper is opened as a pedal 16 is stepped on, and a caster makes contact with the caster stopper 2 and does not slide down. Thereafter, the platform 1 is lowered, and the caster stopper 2 is stepped down and pulled in back. At the time of loading, the pedal 16 is stepped down and the caster stopper 2 is set upright, a slider 9 is made to slide left, and a load is moved onto the platform 1. At that time, the caster steps over the caster stopper 2, and a plate spring 8 pushes up a pressuring part 12 of the spring 9. Since this pressing up force is stronger than a linear spring 7, the caster stopper 2 is made to return.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a tailgate lifter installed at a rear portion of a truck carrier, and more particularly to a tailgate lifter having a caster stopper.

[0002]

2. Description of the Related Art In recent years, various kinds of cargo are transported by using a truck having a container mounted on a loading platform. A tailgate lifter is attached to the rear of the container in order to improve the efficiency and speed of cargo handling work for this container. The tailgate lifter is provided with a platform on which a load is placed, and the platform on which the load is placed is moved up and down to perform cargo handling work. When the platform is on the ground, it is tilted to help the loaded casters slide. However, if the platform is inadvertently tilted while the casters are placed, there is a risk that the casters will start to run and run over the ground or fall from the platform. Also, if the platform is at the same level as the floor of the container and you move the loaded casters from the container onto the platform, the casters will slip on the platform,
There is a risk of falling to the ground. Therefore, a caster stopper is usually provided on the platform to prevent runaway of the caster on the platform.

FIG. 20 is a perspective view showing a conventionally used tailgate lifter, and FIG. 21 is an explanatory view showing its usage state. In these figures, 100 is a truck, and a container 102 is fixed to a rear portion 101 thereof. The rear wall of the container 102 serves as a hoisting and closing door type opening / closing portion 103. A tailgate lifter 104 is provided below the lower portion of the container 102. The tailgate lifter 104 is provided with two swingable arms 105 on the lower rear side of the truck 100, and a platform 106 is attached to the tip thereof. A caster stopper 107 is provided at the tip of the platform 106.

In FIG. 21, the position of the tailgate lifter 104 shown by the solid line shows the state where it is lowered to the ground, and the position of the chain double-dashed line shows the state where the platform 106 is held at the same height as the floor of the container. The state indicated by the alternate long and short dash line shows the state in which the platform 106 is flipped up to the rear wall surface of the container 102. As shown in FIG. 20, the platform 10 of the tailgate lifter 104 is shown.
When 6 is in a solid line state or in a two-dot chain line state, the wheels of the casters 108 mounted on the 6 contact the caster stoppers 107 to prevent the casters 108 from sliding off. Since the platform 106 of such a tailgate lifter is moved up and down for each cargo handling work as shown in FIG. 21 and slid on the platform 106,
It is made of a plate with the smallest possible thickness and a gentle slope. Furthermore, the caster stopper 107
To increase the effective area of the platform 106,
It must be installed at the tip of this.

As such a caster stopper,
A device as disclosed in Japanese Utility Model Publication No. 4-23534 has been conventionally used. The sectional view is shown in FIG. FIG.
FIG. 6 is a partial cross-sectional view showing a tip portion of the platform 106. As can be seen from FIG. 22, the conventional caster stopper 107 has a recess 109 formed on the upper surface of the tip of the platform 106, and the caster stopper 107 having a substantially L-shaped cross section is rotatably supported in the recess 109. (110), and a torsion bar 111 is provided between the bottom surface of the recess 109 and the back surface of the caster stopper 107,
The caster stopper 107 is biased so as to always flip up. When the caster stopper 107 is not used, the torsion bar 111
The caster stopper 107 is retracted against the biasing force of 1 and is locked by the lock member 112 so as not to open. Further, when in use, the locking member 112 is rotated, the lock is released, and the caster stopper 107 is flipped up as shown in FIG. 23 to prevent the wheels 113 of the casters from rolling off the platform 106 and to load the container. In order to
When rolling on the platform 106 from the right side of the caster wheel,
It is pushed by 3 and pulled into the recess 109 of the platform so as not to hinder the rolling of the wheels 113 of the caster. 22 and 23, 114 and 115 are caster stoppers 107.
Is a damper for absorbing a shock when the tip of the shaft rotates and colliding with the bottom surface of the recess 109, or for preventing generation of a shock noise.

[0006]

As described above, the caster stopper has a low sectional height and is exposed to dust and rainwater, and therefore requires a reliable operation with a simple structure. Further, the conventional caster stopper as described above requires a locking device for accommodating the caster stopper in the recess provided in the platform of the tailgate lifter when storing it in the recess. Further, this locking device requires at least two or more at both ends in order to suppress the reaction force that tries to open the caster stopper, and even if it is locked by one locking device, the side that is not fixed does not float up and become flat. There was a problem.

The present invention is intended to improve the above-mentioned conventional drawbacks, and an object of the present invention is to make the caster stopper always project during the loading operation and to retract the carrier into the recess when the carrier exceeds it. An object of the present invention is to provide a tailgate lifter that allows a worker to voluntarily move the caster stopper in and out of the concave portion during the unloading work and does not require a locking device when the caster stopper is accommodated in the concave portion.

[0008]

In order to solve the above-mentioned problems, according to the present invention, a caster stopper for preventing casters from sliding down is provided on the platform surface in a tailgate lifter that can be inserted into and removed from the platform surface. A recess for accommodating a caster stopper, a caster stopper which is accommodated in the recess and has a protruding position for stopping the caster and an accommodating position for allowing the caster to pass, and the caster stopper is held at both the protruding position and the accommodating position. A first elastic means, a second elastic means for pressing the caster stopper to the projecting position with a force larger than the elastic force of the first elastic means when the caster stopper takes the storage position, and the second elastic means. Selector means for selecting whether or not the force of the elastic means can be applied to the caster stopper. Tailgate lifter is provided that.

[0009]

The first elastic means applies an elastic force to the caster stopper so as to position the caster stopper at both extreme positions of the protruding position for stopping the caster and the storage position for passing the caster, and the second elastic means is When the caster stopper takes the storage position, it acts so as to press the caster stopper to the projecting position with a force larger than the elastic force of the first elastic means. The selector is activated during loading work and not activated during unloading work. Therefore, the caster stopper projected by the operator during the loading operation automatically projects by the second elastic means to stop the caster even if the caster steps over and retracts. When the caster stopper is projected during the unloading work, the caster stopper is held at the projected position to stop the caster, and when the caster stopper is retracted, the caster stopper is held at the retracted position.

[0010]

Embodiments of the present invention will be described in detail with reference to the drawings. 1 is a top view showing a part of a platform provided with caster stoppers, FIG. 2 is a partial sectional view showing a state in which the caster stoppers are opened, and FIG. 3 is a partial sectional view showing a state in which the caster stoppers are closed. Is. In FIGS. 1 to 3, reference numeral 1 denotes a platform, and a caster stopper 2 is provided near a tip 1 ′ of the platform around a bearing 4 in a recess 3 provided in the platform 1 as in the conventional example. It is movably supported. A spring bearing 5 having a U-shaped cross section is provided inside the recess 3, and a spring bearing 6 having a U-shaped cross section is provided at the tip of the caster stopper 2. A linear spring 7 bent into an approximately elliptical shape is compressed and inserted between the spring receivers 5 and 6. As shown in FIG. 4, a leaf spring 8 is attached to the bottom surface of the recess 3 so that when the caster stopper 2 is closed, the tip of the leaf spring 8 holds a small distance from the rear surface of the caster stopper 2. . Therefore, the leaf spring 8 cannot bias the caster stopper 2 upward in the state shown in FIG. The leaf spring 8 is the second elastic means.
The caster stopper 2 has a slider 9 (shown in a circle B in FIG. 4) which can slide in its longitudinal direction.
Is provided. As shown in the enlarged view of FIG. 5, the slider 9 has an upper button 10, a screw 11 is inserted through the center of the slider 9 from the upper part toward the lower part, and a pushing pressure portion 12 is provided at the tip of the screw 11. It is screwed on. Pressing part 12
Has an elliptical shape and is fitted into an elongated slide hole 13 formed in the caster stopper 2. A cushion material 14 and a sliding material 15 are inserted between the upper button 10 and the upper surface of the caster stopper 2 to apply a frictional force to the sliding operation of the slider 9. 16 shown in FIG.
Is a pedal provided on the side end of the caster stopper 2, and when the tip of the pedal is stepped on with the foot, the caster stopper 2
Is biased in the opening direction.

Next, the relationship between the opening / closing of the caster stopper 2 and the compressed / extended state of the linear spring 7 will be described. Note that these elastic members are referred to as first elastic means. The state of (a) in FIG. 6 shows the caster stopper 2 stored in the recess 3 of the platform 1,
In this state, the center line of the linear spring 7 connecting the spring bearings 5 and 6 is above the center point 4'of the bearing portion 4, and the repulsive force of the linear spring 7 acts in the direction to close the caster stopper 2. In the state of (b) in FIG. 6, the center point 4 ′ of the bearing portion 4 is located on the center line of the linear spring 7, and the caster stopper 2 is located at a so-called dead point. The state of (c) in FIG. 6 shows a state in which the caster stopper 2 is projected, and in this state, the center line of the linear spring 7 is below the center point 4 ′ of the bearing portion 4, and the linear spring is The repulsive force of 7 acts in the direction in which the caster stopper 2 is projected from the surface of the platform 1.

FIG. 7 is an exploded view of the caster stopper 2 and its peripheral portion in the above embodiment.
In FIG. 7, reference numeral 17 denotes a sound deadening cushion, which is fitted in a fitting recess provided in a portion of the tip end of the caster stopper 2 that comes into contact with the recess wall surface of the platform. Reference numeral 18 denotes a bearing of the rotary shaft, which is inserted into the bearing portion 4. Reference numerals 7a, 7b and 7c show modifications of the specific shape of the linear spring 7.

Next, the operation of the embodiment of the present invention will be described. First, in a state where the tailgate lifter is not used and is placed along the rear wall surface of the container loaded on the vehicle, as shown in FIG. 4, the slider 9 is moved to the right side, and the pressing portion 12 thereof is It is separated from the tip of the leaf spring 8. Therefore, the biasing force of the leaf spring 8 does not reach the caster stopper 2, and when the caster stopper 2 is pushed into the recess 3 of the platform 1, the expansion force of the linear spring 7 causes the caster stopper 2 to move in the recess 3. The state of being pulled in, that is, the state of (a) in FIG. 6 is maintained.

When unloading a load, the caster stopper 2 is opened to the position indicated by the chain double-dashed line in FIG. 21 to align the platform with the floor of the container, and then the operator depresses the pedal 16. This operation causes the caster stopper 2 to rotate, and goes beyond the state of (b) in FIG. 6 to reach the state of (c). In this state, the center line of the linear spring 7 is the bearing 4
Since it passes below the center point 4'of the caster stopper 2, the caster stopper 2 is held in the open state. When the load inside the container is reloaded to the casters from this state and the casters are pulled out onto the platform 1, the wheels of the casters come into contact with the caster stoppers 2 to prevent the wheels from sliding off the platform. Then, after the platform is lowered to the ground and the platform 1 is tilted, the operator steps on the caster stopper 2 and retracts it into the recess 3 to hold it in the state of (a) in FIG. Along with it, you can slide down the platform to unload.

When loading the container from the ground, the slider 9 is slid to the left from the position shown in FIG. 4 with the platform tilted and the pedal 16 depressed to raise the caster stopper 2. This state is shown in FIG. With the caster stopper 2 held in this state, the load is loaded on the casters and moved from the ground onto the platform 1. At this time, the front wheels of the casters step over the caster stopper 2. Therefore, the caster stopper 2 reaches the state of FIG. 10 from the state of FIG. 8 through the state of FIG. At this time, the pressing portion 12 of the slider 9 presses the tip of the leaf spring 8 downward as shown in FIG. When the front wheels of the caster step over the caster stopper 2, the leaf spring 8 pushes up the pushing pressure portion 12 of the slider 9. Since the pushing force of the leaf spring 8 is stronger than the force of holding the caster stopper 2 in the recess 3 by the linear spring 7, the caster stopper 2 returns to the state shown in FIG. Therefore, even if the operator releases his hand from the caster,
The front wheels come into contact with the caster stopper 2 to prevent runaway of this. When the caster is further pushed up onto the platform, the rear wheels of the caster step over the caster stopper 2, but at this time, the same action as when the front wheel oversteps is performed.

Then, after holding the platform horizontally, raise it to the same height as the floor of the container,
After sliding the caster into the container, the slider 9 is moved to the state shown in FIG. 4, the caster stopper 2 is rotated to hold it in the state of FIG. 6A, and then the platform is rotated. Along the rear wall of the container.

FIGS. 12A to 12C show an embodiment of the present invention in which the pedal 16 is attached to the caster stopper 2 by the bolt 19. By stepping on the caster stopper 2 with a foot, the caster stopper 2 can be easily projected. A muffling cushion material 20 is attached to the caster stopper 2. Further, a dust infiltration shield is provided near the caster stopper 2 and the bearing portion 4 of the platform 1. That is, a groove 21 is provided at the base of the caster stopper 2 in the longitudinal direction thereof, and a ridge 22 to be fitted therein is provided on the platform 1 side. With this structure, when the caster stopper 2 is in the recess 3 of the platform 1, it is possible to prevent dust from entering from the bearing portion. In addition, as a structure for preventing the entry of dust, as shown in FIGS. 2 and 3, a structure may be adopted in which a wiping plate 23 made of rubber or a soft synthetic resin sheet is attached to the rear end of the caster stopper 2.

In the above embodiment, the slider 9 is used to select whether or not the force of the leaf spring 8 contributes to the opening force of the caster stopper 2. However, in the embodiment shown in FIG. The caster stopper 2 is rotatably provided so that the operator can rotate it from the front side, and a pushing pressure portion 25 is provided at the tip of the rotary shaft 24. When the force of the leaf spring 8 is to contribute to the opening force of the caster stopper 2, the rotary shaft 24 is rotated to position the pressing portion 25 just above the tip of the leaf spring 8, and the force of the leaf spring 8 is applied to the caster stopper 2. When it is not possible to contribute to the opening force, the rotating shaft 24 is rotated to move the pressing portion 25 to the leaf spring 8.
Be removed from In the embodiment shown in FIG. 14, the rotating body 26 is rotatably supported by the caster stopper 2, and when the force of the leaf spring 8 is to contribute to the opening force of the caster stopper 2, the tip of the rotating body 26 is rotated to move it. Leaf spring 8
The rotor 26 is located right above the tip, and when the force of the leaf spring 8 does not contribute to the opening force of the caster stopper 2, the rotor 26 is rotated to remove it from the leaf spring 8. The slider 9, the rotating mechanism shown in FIG. 13, and the rotating body 26 shown in FIG. 14 are collectively referred to as a selector.

In the above-described embodiment, since the caster stopper 2 is opened, the leaf spring 8 is provided at the bottom of the recess 3 as shown by the dotted line in FIG. 1, but the leaf spring 8 is located at the center. , Area occupation rate is high and area efficiency is poor. Therefore, in the next embodiment, a torsion spring is used instead of the leaf spring 8. FIG. 15 is a top view showing the torsion spring. In the figure, 27 is a torsion spring made of steel wire. One end of the torsion spring 27 is bent at a right angle, and a fixing portion 28 is formed. The other end of the torsion spring 27 is bent at 90 degrees with respect to the axial direction of the torsion spring 27 and is bent at about 45 degrees with respect to the axial direction of the fixed portion 28, and this portion is locked by the torsion spring. It becomes the plate 31.

Next, the mounting of the torsion spring 27 in the recess 3 will be described. The torsion spring 27 is placed on the bottom surface 3'of the recess 3 as shown in FIG. Torsion spring restraining plates 29 and 29 are screwed to both sides of the fixed portion 28 so as to sandwich it from both sides. The thickness of the torsion spring restraint plates 29, 29 is formed to be substantially the same as the wire diameter of the torsion spring 27.
As shown in FIG. 16, an angle restricting portion 32 is provided on the bottom surface 3 ′ of the recess 3. A V-shaped recess is formed in the angle restricting portion 32, the torsion spring 27 is pushed into the recess, and the fixed portion 28 side is pressed against the recess by the torsion spring restraining plate 29 and is supported by the pressing portion 30. The side is pressed against the V-shaped recess of the angle regulating portion 32 by a torsion spring locking plate 31 made in the same manner as the torsion spring restraining plate 29, and is supported at the same time.
Is restrained by the angle restricting portion 32. Therefore, a torsional biasing force is applied to the torsion spring 27. FIG. 17 shows a state in which the caster stopper 2 is pushed in and the pressing portion 12 of the selector presses the pressing portion 30.

FIG. 18 is an explanatory diagram showing the relationship between the torsion angle of the torsion spring and the work amount. In FIG. 17, the horizontal axis represents the torsion angle, and the vertical axis represents the spring force, that is, the torque. As can be seen from FIG. 17, when a bias is applied to the torsion spring at the time of mounting and the torsion spring is further twisted from this state, the torsion spring can perform more work than twisting from the free state. In other words, a small torsion spring can be used. Note that FIG. 19 shows a state in which the spring force of the torsion spring is prevented from acting on the caster stopper 2. In such a state, the pressing portion 30 is provided so that the torsion spring force does not act on the closed caster stopper 2.
A gap S is provided between the tip of the and the caster stopper 2.

Although the present invention has been described with reference to the above-mentioned embodiments, the pedals and selectors are provided at both ends of the caster stopper, and the first and second elastic means are
It is provided at several places including both ends of the caster stopper, multiple caster stoppers are provided in parallel on the platform, multiple caster stoppers are arranged on a line on the platform, etc.
Various modifications and applications are possible within the scope of the present invention, and these modifications and applications are not excluded from the scope of the present invention.

[0023]

As described in detail above, the present invention provides
A recess for accommodating the caster stopper provided on the platform surface, a caster stopper that is housed in the recess and has a projecting position for stopping the caster and a storage position for allowing the caster to pass, and both the projecting position and the storage position for the caster stopper. First elastic means for respectively holding the first position and the first elastic means when the caster stopper is in the storage position.
Second elastic means for pressing the caster stopper to the protruding position with a force greater than the elastic force of the elastic means of the second elastic means,
Since the selector means for selecting whether or not the force of the elastic means can be applied to the caster stopper is provided, the caster stopper can be housed in the recess without providing the locking means, and the selector can be loaded during loading work. It does not work during unloading work. Therefore, the caster stopper projected by the operator during the loading operation automatically projects by the second elastic means to stop the caster even if the caster steps over and retracts. When the caster stopper is projected during the unloading work, the caster stopper is held at the projected position to stop the caster, and when the caster stopper is retracted, the caster stopper is held at the retracted position. In addition to this, since a dust invasion shield is provided, it is possible to prevent dust from entering the recesses from the vicinity of the caster stopper.

[Brief description of drawings]

FIG. 1 is a partial top view showing a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the platform.

FIG. 3 is a partial cross-sectional view of the platform.

FIG. 4 is a partial sectional view of a slider portion.

FIG. 5 is a sectional view of a slider.

FIG. 6 is an operation explanatory view of a caster stopper.

FIG. 7 is an exploded cross-sectional view of a main part.

FIG. 8 is an operation explanatory view of a caster stopper.

FIG. 9 is an operation explanatory view of a caster stopper.

FIG. 10 is an operation explanatory view of a caster stopper.

FIG. 11 is a partial cross-sectional view of a slider portion.

FIG. 12 is an explanatory view showing another embodiment of the pedal.

FIG. 13 is a perspective view showing another embodiment of the selector.

FIG. 14 is a perspective view showing still another embodiment of the selector.

FIG. 15 is a front view of a torsion spring.

FIG. 16 is a cross-sectional view showing a mounted state of a torsion spring.

FIG. 17 is an operation explanatory view of the torsion spring.

FIG. 18 is an operation explanatory view of the torsion spring.

FIG. 19 is an operation explanatory view of the torsion spring.

FIG. 20 is a perspective view of a conventional example.

FIG. 21 is an operation explanatory diagram of a conventional example.

FIG. 22 is a cross-sectional view of a conventional caster stopper.

FIG. 23 is an operation explanatory view of the caster stopper of the conventional example.

[Explanation of symbols]

 1 ... Platform 1 '... Tip 2 ... Caster stopper 3 ... Recess 4 ... Bearing 4' ... Center point 5 ...・ Spring holder 6 ・ ・ ・ ・ ・ Spring holder 7 ・ ・ ・ ・ ・ Linear spring 8 ・ ・ ・ Plate spring 9 ・ ・ ・ Slider 10 ・ ・ ・ Upper button 11 ・ ・ ・ Screw 12-Pressing portion 13-Slide hole 14-Cushion material 15-Sliding material 16-Pedal 17-Silent cushion 18 ... Bearings 19 ... Bolts 20 ... Cushion materials 21 ... Grooves 22 ... Projections 23 ... Wiping plates 24 ... -Rotary shaft 25-Pressing portion 26-Rotating body 27-Torsion spring 28-Fixing portion 29- -Torsion spring restraint plate 30-Pressure plate 31-Torsion spring locking plate 32-Angle regulation part 33-Bearing plate 100-Track 101・ ・ ・ ・ Rear part 102 ・ ・ ・ Container 103 ・ ・ ・ Opening / closing part 104 ・ ・ ・ Tailgate lifter 105 ・ ・ ・ Arm 106 ・ ・ ・ Platform 107 ・ ・ ・ Caster Stopper 108-Caster 109-Recess 110-Spindle 111-Torsion bar 112-Lock material 113-Wheel 114- ..Damper 115 ... Damper

Claims (8)

[Claims] 1. A tailgate lifter provided with a caster stopper for preventing casters from slipping out from a platform surface so that the caster stopper can be accommodated in the platform surface and a caster stopper housing recess in the platform surface. A caster stopper that takes a projecting position and a storage position that allows the casters to pass through, a first elastic means that holds the caster stopper at both the projecting position and the storage position, and a first elastic means when the caster stopper takes the storage position. Second elastic means for pressing the caster stopper to the projecting position with a force larger than the elastic force of the first elastic means, and selector means for selecting whether or not the force of the second elastic means can be exerted on the caster stopper. A tailgate lifter comprising: 2. The tailgate lifter according to claim 1, further comprising at least one pedal fixed to the caster stopper. 3. The caster stopper is provided at the full width of the platform, and has a first stopper at least at both ends thereof.
The tailgate lifter according to claim 1, further comprising a second elastic means. 4. The tailgate lifter according to claim 1, wherein the caster stopper is formed at the most distal end of the platform. 5. The tailgate lifter according to claim 1, wherein a plurality of the caster stoppers are arranged in a line on the platform. 6. The tailgate lifter according to claim 1, wherein the caster stopper is provided in a plurality of lines in parallel on the platform. 7. The tailgate lifter according to claim 1, wherein the second elastic means comprises a torsion spring. 8. The tailgate lifter according to claim 1, further comprising a dust entrance guard provided near the bearing portion of the caster stopper to prevent dust from entering the bearing portion.