JP2013116647A - Coupling device - Google Patents

Abstract

The present invention provides a connecting device that can reduce a burden on an operator and perform a connecting operation safely.
A connecting device 1 is used when connecting a tow transportation cart 6 and a preceding vehicle 7. The connecting device 1 includes a base portion 2, a freely turnable free wheel 221 provided on the lower front side of the base portion 2, a non-turnable fixed wheel 222 provided on the lower rear side of the base portion 2, and a standing posture. And a handle portion 23 provided so as to be arranged at a height that can be gripped by an operator. The coupling device 1 includes a rear engagement portion 4 provided to be engageable with a carriage side engaged portion 61 disposed at a front end of the transport carriage 6, and a vehicle side cover disposed at a rear end of a preceding vehicle 7. The front engagement portion 3 is provided so as to be engageable with the engagement portion 72. The coupling device 1 includes a fixed ring floating mechanism 5 for floating the fixed ring 222 from the floor surface in a state where the rear engagement portion 4 is engaged with the cart-side engaged portion 61.
[Selection] Figure 1

Description

  The present invention relates to a connecting device used when connecting a tow transportation cart and a preceding vehicle arranged in front of the towing cart.

In an automobile manufacturing process or the like, there is a case where a transport cart loaded with a work or the like is connected to a tow vehicle, and the workpiece is transported by towing the transport cart by the tow vehicle.
Conventionally, the connection between the tow vehicle and the transport cart is performed by a connector 9 as shown in FIGS. 10 and 11.

  The connector 9 includes a main body portion 90 including a vehicle-side engagement portion 91 formed in an annular shape, and a carriage-side engagement portion 92 having a substantially U-shaped cross section. The main body 90 is disposed on the carriage side engaging portion 92 via a bracket 93 and a rotation shaft, and is connected to each other so as to be rotatable. The connector 9 engages the vehicle-side engaging portion 91 with a connecting bar (not shown) of the towing vehicle, and engages the cart-side engaging portion 92 with the frame portion 95 of the transporting carriage to be pulled. The tow vehicle and the transport cart can be connected.

  Further, Patent Document 1 discloses a coupling device in which a tow vehicle is provided with a twist lock, and a transport cart is provided with an engaging portion that engages with the twist lock.

JP 2002-307918 A

By the way, the connecting device described above has the following problems.
When connecting the transport cart and the towing vehicle using the connecting tool 9, the operator carries the connecting tool 9 and performs the connecting work. At this time, the connecting bar of the tow vehicle is often arranged at a low position in the height direction. Further, in order to stably pull the transport cart by the towing vehicle, it is preferable to arrange the connector 9 in parallel with the traveling direction, and also in the transport cart, it is disposed at the front lower end of the transport cart that engages the cart-side connecting portion. The frame portion 95 is engaged.

  For this reason, when the connecting tool 9 is connected to the transport cart and the towing vehicle, the work posture is such that the operator bends and bends, increasing the burden on the operator and increasing the operator's hand. There is a risk of pinching. Since such an operation is performed while the operator pays attention, it is difficult to increase the operation speed and the operation time tends to be long.

Moreover, in the connection apparatus shown by patent document 1, it is necessary to provide a dedicated engaging part in a conveyance trolley, and the physique of a conveyance trolley tends to become large. There are cases where a plurality of transport carts are loaded and transported on a truck or the like with workpieces loaded thereon. When the size of the transport cart is increased, the load form becomes larger, and the quantity that can be loaded on the truck or the like may be reduced.
In addition, a plurality of transport carts are required for each type of work, and when all the transport carts are provided with engaging portions, the equipment cost increases.

  The present invention intends to provide a connecting device that can reduce the burden on the worker and can safely perform the connecting operation.

One aspect of the present invention is a connecting device used when connecting a tow truck and a preceding vehicle arranged in front thereof,
A base part;
A freely rotatable swivel wheel provided on the lower front side of the base portion;
A non-turnable stationary wheel provided on the lower rear side of the base portion;
A handle portion provided so as to be arranged at a height that can be gripped by a worker in a standing posture;
A rear engagement portion provided to be engageable with a cart-side engaged portion disposed at a front end of the transport cart;
A front engagement portion provided to be engageable with a vehicle side engaged portion disposed at a rear end of the preceding vehicle;
A coupling device having a fixed ring floating mechanism for floating the fixed wheel from the floor surface in a state where the rear engagement portion is engaged with the cart side engaged portion. (Claim 1).

  The coupling device includes the universal wheel, the fixed wheel, and the handle portion. Therefore, the conventional connecting tool is used for the connecting operation of moving the connecting device, connecting the rear engaging portion and the front engaging portion to the cart side engaged portion and the vehicle side engaged portion, respectively. It can be performed in a standing posture without bending the waist as if it were. Further, since the coupling device can be operated by the handle portion, a hand is provided between the rear engagement portion and the front engagement portion, and the carriage side engaged portion and the vehicle side engaged portion. Etc. can be prevented. Therefore, the burden on the worker can be reduced and the work can be performed safely.

  In addition, there is a fixed wheel floating mechanism for floating the fixed wheel from the floor surface in a state where the rear engagement portion is engaged with the cart side engaged portion. Thereby, the said conveyance cart can be easily bent also in the state which connected the said connection apparatus and the said conveyance cart.

  That is, the transport cart is often provided with a free wheel and a fixed wheel in order to stably perform both straight traveling and curved traveling. In such a case, if the fixed wheel of the coupling device and the fixed wheel of the transport cart are both in contact with the ground, it becomes difficult to bend the transport cart due to the difference between the inner and outer wheels. Therefore, the fixed wheel levitation mechanism of the connecting device lifts the fixed wheel of the connecting device to eliminate the influence due to the difference between the inner and outer wheels, and the carrier cart can be easily bent.

  Thus, according to the said connection apparatus, the burden to an operator can be reduced and a connection operation | work can be performed safely.

Explanatory drawing which shows the connection apparatus which connected the conveyance trolley | bogie and a preceding vehicle in Example 1. FIG. 3 is a side view showing the coupling device in the first embodiment. The rear view which shows the connection apparatus in Example 1. FIG. FIG. 3 is a plan view showing the coupling device in the first embodiment. Explanatory drawing which shows the connection apparatus connected with the conveyance trolley | bogie in Example 1. FIG. Explanatory drawing which shows the connection apparatus connected with the front vehicle in Example 1. FIG. FIG. 3 is a partially enlarged view showing a front engagement portion in the first embodiment. The principal part enlarged view which shows the fixed ring floating mechanism of the raise state in Example 1. FIG. The principal part enlarged view which shows the fixed ring levitation mechanism of the descent | fall state in Example 1. FIG. Explanatory drawing which shows a connection tool in background art. The side view which shows the trolley | bogie side engaging part in background art.

  In the coupling device, the fixed-wheel levitation mechanism is provided in the rear engagement portion, and the rear engagement portion extends rearward from the base portion and is located above the carriage-side engaged portion. It has a rear grip part that is opposed to be movable up and down, and is configured so that the rear end side of the base part and the fixed ring can be relatively lifted by lowering the rear grip part. (Claim 2). In this case, it is possible to easily perform the connecting operation between the rear gripping portion and the cart side engaged portion and the floating of the fixed wheel in one operation.

  In addition, the rear engaging portion has a receiving portion that extends rearward from the base portion and is provided at a height that allows insertion with a predetermined space below the cart-side engaged portion. The receiving portion is spaced from the predetermined space, and the carriage side engaged portion is inserted, and then the rear gripping portion is lowered to relatively raise the receiving portion, so that the receiving portion and the carriage side covered portion are lifted. You may comprise so that the said predetermined space between engagement parts may be lost (Claim 3). In this case, the rear engaging portion and the receiving portion are arranged so as to sandwich the cart-side engaged portion. Thereby, it can prevent that the engagement with the said back engaging part and the said cart side engaged part is cancelled | released unintentionally.

  The fixed-wheel levitation mechanism includes a cylinder portion that can be expanded and contracted in the vertical direction and an arm portion that is arranged to be rotatable about a central axis perpendicular to the vertical direction. Either one of the parts may be connected to one end of the arm part, and the other may be connected to an intermediate part located between both ends of the arm part. In this case, by operating the other end of the arm portion, the rear gripping portion can be lifted and the fixed wheel can be lifted reliably and easily.

Example 1
An embodiment according to the coupling device will be described with reference to FIGS.
As shown in FIG. 1, the connecting device 1 of this example is used when connecting a tow transportation cart 6 and a preceding vehicle 7 arranged in front thereof. The connecting device 1 includes a base portion 2, a freely turnable free wheel 221 provided on the lower front side of the base portion 2, a non-turnable fixed wheel 222 provided on the lower rear side of the base portion 2, and a standing posture. And a handle portion 23 provided so as to be arranged at a height that can be gripped by an operator.

Further, the connecting device 1 includes a rear engagement portion 4 provided to be engageable with a cart-side engaged portion 61 disposed at a front end of the transport cart 6, and a vehicle disposed at a rear end of the preceding vehicle 7. And a front engagement portion 3 provided to be engageable with the side engaged portion 72.
The coupling device 1 includes a fixed ring floating mechanism 5 for floating the fixed ring 222 from the floor surface in a state where the rear engagement portion 4 is engaged with the cart-side engaged portion 61.

Hereinafter, the connecting device 1 of this example will be described in more detail.
As shown in FIG. 1, the connecting device 1 connects a transport cart 6 configured to be able to load a workpiece 8 and a preceding vehicle 7 that pulls the transport cart 6.

  As shown in FIG. 1, the transport cart 6 includes a frame body portion 62 on which the workpiece 8 is loaded, and transport wheels provided on the lower surface of the frame body portion 62. The frame body portion 62 is arranged so as to connect a bottom portion 621 formed by combining rectangular pipes in a lattice shape, and a plurality of supporting column portions 623 erected upward from the outer periphery of the bottom portion 621 and adjacent supporting column portions 623. And an enclosure portion 622 including the beam portion 624. In this example, at the bottom portion 621 of the frame body portion 62, the rectangular pipe perpendicular to the traveling direction disposed at the front end portion in the traveling direction forms the cart side engaged portion 61 in the transport cart 6, and the rear of the coupling device 1. The engaging part 4 is configured to be engageable.

  On the lower surface of the bottom portion 621, a pair of universal wheels 631 arranged in a direction perpendicular to the traveling direction is disposed at a position in front of the traveling direction, and a position perpendicular to the traveling direction is disposed at a position behind the traveling direction. A pair of fixed wheels 632 arranged side by side are arranged.

  As shown in FIG. 1, the preceding vehicle 7 includes a drive source, drive wheels 71 that are rotated by transmission of the drive force, and steered wheels (not shown) that can be steered by a driver's operation. In addition, it is configured to be able to travel on its own with freedom of curvature. As shown in FIG. 1, a vehicle-side engaged portion 72 is provided at the rear end of the preceding vehicle 7. The vehicle-side engaged portion 72 includes a vehicle extension portion 721 that protrudes rearward, and an engagement pipe portion 722 that stands upward from the upper surface of the vehicle extension portion 721, and a coupling device 1 is configured so as to be engageable with one front engaging portion 3.

  As shown in FIG. 2, the connecting device 1 that connects the transport carriage 6 and the preceding vehicle 7 includes the forward engagement portion 3 that engages with the vehicle-side engaged portion 72 of the preceding vehicle 7 and the transport as described above. The rear engagement portion 4 that engages with the carriage-side engaged portion 61 of the carriage 6 and the base portion 2 on which the front engagement portion 3 and the rear engagement portion 4 are arranged are provided.

  As shown in FIG. 4, the base portion 2 includes a pair of base frames 21 that are substantially rectangular when viewed from above, and a connection frame 211 that is arranged to connect the pair of plate portions. As shown in FIGS. 2 to 4, the base portion 2 includes the front engagement portion 3 and the rear engagement portion 4, traveling wheels for traveling on the floor surface, and an operator connecting device 1. Are provided with a handle portion 23 and a receiving portion 25 disposed below the rear engagement portion 4.

  As shown in FIGS. 2 to 4, the traveling wheel provided on the lower surface of the base portion 2 includes a pair of free-turning free wheels 221 provided on the front side in the traveling direction on the lower surface of the base portion 2, and the traveling direction. It consists of a pair of fixed wheels 222 which are provided on the rear side and cannot be turned.

  As shown in FIGS. 2 to 4, the handle portion 23 provided on the upper surface of the base portion 2 is formed of a cylindrical pipe formed in a substantially U-shape (see FIG. 3). While being brought into contact with the upper surface, it is erected upward. The upper end of the handle portion 23 is disposed at a height that can be gripped by a worker in a standing posture.

  As shown in FIG. 7, the front engagement portion 3 provided in front of the lower end of the handle portion 23 includes an annular engagement end portion 31 and a pair of extended pipe portions 32 extending from the engagement end portion 31. And. The pair of extending pipe portions 32 includes an inclined portion 33 that is arranged so that the distance between the extending pipe portions 32 increases as the distance from the engaging end portion 31 increases, and a parallel portion 34 that is arranged so that the distance between the extending pipe portions 32 is constant. doing. An engaging rotation shaft 35 extending in the lateral direction is formed at the end of the parallel portion 34 opposite to the side where the inclined portion 33 is disposed, and penetrates the pair of brackets 24 disposed in front of the lower end of the handle portion 23. The long hole 241 is inserted and supported.

As shown in FIG. 2, the pair of brackets 24 that pivotally support the front engaging portion 3 have two support pipes 242 and 243.
One support pipe 242 is disposed near the upper end of the long hole 241 of the bracket 24 and on the rear side of the long hole 241 so as to connect the opposing surfaces of the pair of brackets 24. The support pipe 242 is for preventing the front engaging portion 3 arranged so as to be erected upward shown in FIG.

  The other support pipe 243 is arranged so as to connect the opposed surfaces of the pair of brackets 24 in the vicinity of the center in the longitudinal direction of the long hole 241 of the bracket 24 and on the front side of the long hole 241. The support pipe 243 is intended to prevent the front engaging portion 3 arranged so as to stand up in the direction shown in FIG. 2 from falling forward. As shown in FIG. 6, the front engaging portion 3 is raised so that the engaging rotation shaft 35 is positioned above the support pipe 242 disposed on the front side, whereby the engagement rotation shaft 35 is set as the rotation center. Can be tilted forward while rotating.

As shown in FIG. 2, the rear engagement portion 4 is arranged at the position on the rear end side of the base portion 2 as described above.
The rear engagement portion 4 includes a fixed wheel floating mechanism 5 that floats the fixed wheel 222, and a rear grip portion that extends rearward from the base portion 2 and is disposed so as to be movable up and down above the carriage-side engaged portion 61. 42.

As shown in FIGS. 8 and 9, the fixed-wheel levitation mechanism 5 includes a cylinder portion 51 that can be expanded and contracted in the vertical direction, one end rotatably connected to the rear grip portion 42 side, and an intermediate portion 522 rotated to the base portion 2 side. And an ascending pedal arm 52 connected to each other.
The cylinder part 51 has a lower cylinder part 511 fixed to the base part 2 and an upper cylinder part 512 arranged to be expanded and contracted relative to the lower cylinder part 511 so as to be movable up and down. The cylinder portion 51 includes a tension spring (not shown) and applies a biasing force to contract the cylinder portion 51. A flat plate elevating plate 513 is disposed at the upper end of the upper cylindrical portion 512.

  The ascending pedal arm 52 is rotatably connected to the lower surface of the elevating plate 513 via a link portion 521 disposed at one end thereof. The lift pedal arm 52 is coupled to the lower cylinder portion 511 of the cylinder portion 51 so that the intermediate portion 522 located in the middle of the longitudinal direction can be rotated around a rotation axis orthogonal to the raising / lowering direction of the cylinder portion 51. ing.

  In the lowered state shown in FIG. 9, when the operator steps down the other end of the lift pedal arm 52, one end of the lift pedal arm 52 is lifted as shown in FIG. 8. At this time, the ascending pedal arm 52 and the link portion 521 are arranged on a substantially straight line, and a part of the link portion 521 contacts the cylinder portion 51. Thereby, the link part 521 and the raising pedal arm 52 are fixed, and as shown in FIG. 2, the fixed ring floating mechanism 5 is fixed in the rising state. Further, when the raising pedal arm 52 is stepped down, the lowering pedal arm connected to the raising pedal arm 52 rises relatively.

The fixed wheel levitation mechanism 5 includes a lowering pedal arm 53 for switching from the rising state to the lowering state. In the ascending state shown in FIG. 8, the operator depresses the descending pedal arm 53 to generate a force for pulling the link part 521 away from the cylinder part 51. Thereby, fixation of the link part 521 and the raising pedal arm 52 is cancelled | released, the cylinder part 51 shrink | contracts with the urging | biasing force of an urging means, and the fixed wheel levitation mechanism 5 will be in a descent | fall state. At this time, the fixed wheel levitation mechanism 5 is maintained in the lowered state by the urging force of the urging means.

  For the fixed wheel levitation mechanism 5 having the above-described configuration, for example, a positive hammer lock or floor lock by Tosho Vehicle Co., Ltd. can be used.

As shown in FIGS. 2 to 4, a support arm portion 41 having a rear gripping portion 42 is arranged on the lifting plate 513 in the fixed ring floating mechanism 5.
The support arm portion 41 includes a support arm fixing portion 411 that is fixed to the upper surface of the elevating plate 513, a portion that extends downward from both ends of the support arm fixing portion 411, and a rear portion that extends from the lower end thereof. The shape which connected the part and the part extended below from the rear end is exhibited.

As shown in FIGS. 2 to 4, a rear grip 42 is arranged at the lower end of the support arm 41.
The rear gripping portion 42 has a gripping main body portion 421 formed in a substantially U-shape that opens downward, and can be engaged with and gripped by the cart-side engaged portion 61. When the fixed wheel levitation mechanism 5 is lowered and the rear gripping portion 42 is lowered, the height position of the gripping main body portion 421 is arranged to be lower than the height position of the cart side engaged portion 61.

As shown in FIGS. 2 to 4, the receiving portion 25 is disposed below the rear grip portion 42.
The receiving portion 25 has a receiving fixing portion 251 that hangs down from the rear end of the base portion 2, and extends rearward from the lower end of the receiving fixing portion 251. The receiving portion 25 is provided below the carriage-side engaged portion 61 at a height that allows insertion of the receiving portion 25 with a predetermined space therebetween. After insertion, the receiving portion 25 is relatively raised by lowering the rear gripping portion 42 so that the predetermined space between the receiving portion 25 and the cart side engaged portion 61 is eliminated. .

The transport cart 6 and the preceding vehicle 7 are connected by the connecting device 1 configured as described above.
As shown in FIG. 2, the coupling device 1 is moved so that the rear gripping portion 42 is disposed above the cart-side engaged portion 61. At this time, the operator can hold and move the handle portion 23 described above. Then, as shown in FIG. 5, the lowering pedal arm 53 of the fixed wheel floating mechanism 5 is stepped down, and the rear gripping portion 42 is lowered.

  Since the lower position of the rear gripping portion 42 is lower than the height position of the cart-side engaged portion 61, the base portion is relatively disposed after the rear gripping portion 42 contacts the upper surface of the cart-side engaged portion 61. The rear side of 2 rises. Thereby, a pair of fixed ring 222 distribute | arranged to the lower surface back side of the base part 2 raises.

At this time, the receiving portion 25 rises so that the predetermined space between the receiving portion 25 and the cart side engaged portion 61 disappears as the rear end side of the base portion 2 rises.
Thereby, the connection between the connecting device 1 and the transport cart 6 is completed.

Next, as shown in FIG. 6, the connecting device 1 and the preceding vehicle 7 are connected.
By raising the front engagement portion 3 in the storage state so that the engagement rotation shaft 35 is positioned above the support pipe 242 disposed on the front side, the engagement rotation shaft 35 is set as the rotation center. It can be tilted forward while rotating. Then, by engaging the engagement end portion 31 tilted forward with the vehicle-side engaged portion 72 of the preceding vehicle 7, the connection device 1 and the towing vehicle 7 are connected. Thereby, the connection between the transport cart 6 and the towing vehicle 7 by the connecting device 1 is completed.

Next, the effect of the coupling device 1 of this example will be described.
The coupling device 1 of this example includes a free wheel 221, a fixed wheel 222, and a handle part 23. Therefore, the movement of the connecting device 1, the connecting operation of connecting the rear engaging portion 4 and the front engaging portion 3 to the cart side engaged portion 61 and the vehicle side engaged portion 72, respectively, are performed using a conventional connecting tool. It can be performed in a standing posture without bending the waist as if it were. In addition, since the coupling device 1 can be operated by the handle portion 23, a hand is provided between the rear engagement portion 4 and the front engagement portion 3, and the carriage side engaged portion 61 and the vehicle side engaged portion 72. Etc. can be prevented. Therefore, the burden on the worker can be reduced and the work can be performed safely.

  Further, in the state in which the rear engagement portion 4 is engaged with the cart-side engaged portion 61, the stationary wheel lift mechanism 5 for floating the fixed wheel 222 from the floor surface is provided. Thereby, also in the state which connected the connection apparatus 1 and the conveyance trolley 6, the conveyance trolley 6 can be bent easily.

  That is, the transport cart 6 includes a free wheel 631 and a fixed wheel 632 in order to stably perform both straight traveling and curved traveling. Therefore, if the fixed wheel 222 of the coupling device 1 and the fixed wheel 632 of the transport carriage 6 are both in contact with the ground, it becomes difficult to make the transport cart 6 bend due to the difference between the inner and outer rings. Therefore, the fixed wheel levitation mechanism 5 of the coupling device 1 lifts the fixed wheel 222 of the coupling device 1 to eliminate the influence due to the difference between the inner and outer wheels, and the transport carriage 6 can be easily bent.

  In the coupling device 1, the fixed-wheel levitation mechanism 5 is provided in the rear engagement portion 4, and the rear engagement portion 4 extends rearward from the base portion 2 and is located above the carriage-side engaged portion 61. And the rear grip part 42 arranged so as to be movable up and down, and by lowering the rear grip part 42, the rear end side of the base part 2 and the fixed ring 222 can be relatively lifted. . Therefore, the connecting operation between the rear gripping portion 42 and the cart side engaged portion 61 and the floating of the fixed ring 222 can be easily performed with one operation.

  Further, the rear engagement portion 4 has a receiving portion 25 that extends from the base portion 2 to the rear side and is provided below the carriage side engaged portion 61 at a height that allows insertion with a predetermined space. Then, after inserting the carriage-side engaged portion 61 with the receiving portion 25 spaced from the predetermined space, the rear gripping portion 42 is lowered to raise the receiving portion 25 relatively, and the receiving portion 25 and the carriage The predetermined space between the side engaged portion 61 is eliminated. Therefore, the rear engaging portion 4 and the receiving portion 25 are arranged so as to sandwich the cart-side engaged portion 61. Thereby, it can prevent that engagement with the back engaging part 4 and the trolley | bogie side engaged part 61 is cancelled | released unintentionally.

  The fixed-wheel levitation mechanism 5 includes a cylinder portion 51 that can be expanded and contracted in the vertical direction, and a lift pedal arm 52 that is arranged to be rotatable about a central axis perpendicular to the vertical direction. Alternatively, either one of the base portions 2 is connected to one end of the raising pedal arm 52, and the other is connected to an intermediate portion 522 located between both ends of the raising pedal arm 52. Therefore, by operating the other end of the lifting pedal arm, the rear grip 42 can be lifted and the fixed wheel 222 can be lifted easily and reliably.

  Thus, according to the coupling device 1 of the present example, the burden on the operator can be reduced, and the coupling work can be performed safely.

DESCRIPTION OF SYMBOLS 1 Connecting device 2 Base part 221 Free wheel 222 Fixed wheel 23 Handle part 3 Front engagement part 4 Rear engagement part 5 Fixed wheel floating mechanism 6 Carriage truck 61 Carriage side engaged part 7 Predecessor vehicle 72 Vehicle side engaged part

Claims (4)

It is a connecting device used when connecting a tow truck and a preceding vehicle arranged in front of it,
A base part;
A freely rotatable swivel wheel provided on the lower front side of the base portion;
A non-turnable stationary wheel provided on the lower rear side of the base portion;
A handle portion provided so as to be arranged at a height that can be gripped by a worker in a standing posture;
A rear engagement portion provided to be engageable with a cart-side engaged portion disposed at a front end of the transport cart;
A front engagement portion provided to be engageable with a vehicle side engaged portion disposed at a rear end of the preceding vehicle;
A coupling device, comprising: a fixed wheel levitation mechanism for levitation of the fixed wheel from a floor surface in a state where the rear engagement portion is engaged with the cart side engaged portion. 2. The coupling device according to claim 1, wherein the fixed-wheel levitation mechanism is provided in the rear engagement portion, and the rear engagement portion extends rearward from the base portion and is engaged in the cart side engagement. It has a rear gripping part that is opposed to be movable up and down above the joint part,
A connecting device, wherein the rear gripping portion is lowered so that the rear end side of the base portion and the fixed ring can be relatively lifted.   The connecting device according to claim 2, wherein the rear engagement portion is provided at a height that extends from the base portion to the rear side and that can be inserted with a predetermined space below the cart side engaged portion. After inserting the carriage side engaged part with the predetermined space being opened, and then raising the receiving part relatively by lowering the rear gripping part, A coupling device configured to eliminate the predetermined space between the receiving portion and the cart-side engaged portion.   4. The coupling device according to claim 2, wherein the fixed wheel levitation mechanism includes a cylinder portion that can be vertically expanded and contracted, and an arm portion having one end coupled to the rear grip portion, and an intermediate portion of the arm portion. The connecting portion is swingably connected to the base portion.

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