Traction devices and automated guided vehicles

Abstract

To provide a traction gear capable of reducing a load applied on a motor shaft of a motor.SOLUTION: A traction gear 21 comprises: a turning arm 30 connected so as to be turnable about a turning shaft in a vertical direction orthogonal to the advancing direction of an unmanned carrier body 20; and a lifting arm 31 moved in the vertical direction with respect to the turning arm 30. The lifting arm 31 has a hook 32 connected to a traction object, and a cam follower 34. An end surface cam 33 is installed in the turning arm 30 so as to be rotatable about a cam rotary shaft 67 in the vertical direction. The end surface cam 33 has a cam surface 68 annularly formed about the cam rotary shaft 67 to support the cam follower 34. A motor 35 for rotating the end surface cam 33 is installed in the turning arm 30. By lifting the lifting arm 31 via the cam follower 34 through the rotation of the end surface cam 33, the position of the hook 32 is changed to a position for connection to the traction object and a position for releasing the traction object.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a traction device used in an automated guided vehicle that tows a towed object, and to an automated guided vehicle using this traction device. [Background technology]

[0002] Conventionally, there has been known an automated guided vehicle that pulls a carriage as a towing object, as described in, for example, Patent Document 1. This automated guided vehicle is equipped with a towing device for pulling the carriage.

[0003] The traction device comprises a swivel arm that is connected to the automatic guided vehicle so that it can rotate horizontally, and a lifting arm that moves up and down vertically relative to the swivel arm. A drive unit is installed on the swivel arm with its output shaft in the horizontal direction, and a cam is attached to the output shaft of the drive unit. The drive unit drives the cam to rotate, causing the lifting arm to rise and fall, and the lifting arm engages and disengages with the cart. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6629436 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned traction device, a cam attached to the output shaft of the drive unit is rotated, so that in addition to the load when rotating the cam, the output shaft of the drive unit is also subjected to the load of the lifting arm that is applied to the cam.

[0006] An object of the present invention is to provide a traction device and an automatic guided vehicle that can reduce the load applied to the output shaft of the drive unit. [Means for solving the problem]

[0007] The traction device of the present invention comprises: a lifting arm that moves up and down relative to the swivel arm and has a connecting portion that connects to the towed object and a cam follower; a rotary cam that is installed on the swivel arm so as to be rotatable around the vertical cam rotation axis and has a cam surface that is formed in an annular shape centered on the cam rotation axis and supports the cam follower; and a rotary cam drive unit that is installed on the swivel arm and rotates the rotary cam. The rotation of the rotary cam raises and lowers the lifting arm via the cam follower, thereby changing the position of the connecting portion between a position where it connects to the towed object and a position where it releases the towed object. [Effects of the Invention]

[0008] According to the traction device of the present invention, the load applied to the output shaft of the drive unit can be reduced. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view of an automated guided vehicle using a traction device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view of the traction device with the cover removed. [Figure 3] FIG. 2 is a perspective view showing the internal structure of the traction device. [Figure 4] FIG. 2 is a perspective view showing the internal structure of the traction device. [Figure 5] 1A and 1B show the traction device, in which FIG. 1A is a side view of the lifting arm in a lowered state, and FIG. 1B is a side view of the lifting arm in a raised state. [Figure 6] 10 is a flowchart showing a disconnection operation including a positioning operation of the swing arm of the traction device. [Figure 7] 10(a) to 10(d) are side views showing a disconnection operation including a positioning operation of the swivel arm of the traction device. [Figure 8]10A to 10D show modified examples of the positioning structure of the swivel arm of the traction device, where 10A to 10C are side views of the positioning and holding mechanism, and 10D is a front view of the fitted member for positioning. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will now be described with reference to the drawings.

[0011] 1 shows an automated guided vehicle 10. The automated guided vehicle 10 tows a towed object 11 and automatically travels toward a predetermined transport location.

[0012] The towed object 11 is, for example, a dolly, and is capable of traveling by means of a plurality of wheels 12. A coupled part 13 that is coupled to the wireless guided vehicle 10 is installed at the end of the towed object 11. The coupled part 13 has a coupling member 16 that has a coupling hole 15 that opens in the vertical direction, arranged inside a coupling frame 14 that has a roughly U-shaped cross section with open end faces and top and bottom faces.

[0013] The automatic guided vehicle 10 comprises an automatic guided vehicle body 20 and a traction device 21 installed on the automatic guided vehicle body 20.

[0014] The automated guided vehicle body 20 has a pair of running wheels 22 arranged on both sides in the width direction and a plurality of rotatable casters 23, allowing it to travel and move. Each running wheel 22 of the automated guided vehicle body 20 is rotationally driven by an individual running wheel motor, allowing it to move forward, backward, turn, and change direction at a certain position. The automated guided vehicle body 20 is equipped with a control device that controls the automated guided vehicle body 20 and the traction device 21, a battery that supplies power, etc.

[0015] 1 shows a side view of the traction device 21 with the cover 24 attached, and Fig. 2 shows a perspective view with the cover 24 removed. Figs. 3 and 4 show the internal structure of the traction device 21, and Figs. 5(a) and (b) show the structure and operation of the traction device 21.

[0016] The traction device 21 comprises a swivel arm 30 whose front end, which is one end in the longitudinal direction and corresponds to the direction of travel, is connected to the automatic guided vehicle main body 20 so as to be rotatable in the horizontal direction; a lifting arm 31 which is installed on the other end, i.e., the rear end, of the swivel arm 30 so as to be able to move up and down in the vertical direction; a hook 32 which is a connecting part installed at the lower rear end of the lifting arm 31; an end cam 33 which is a rotating cam installed on the top surface of the swivel arm 30; a cam follower 34 which is installed on the lifting arm 31; a motor 35 which is a rotating cam drive part installed on the top surface of the swivel arm 30; a transmission mechanism 36 which transmits driving force from the motor 35 to the end cam 33; and a positioning and holding mechanism 37 which positions and holds the swivel arm 30 in a fixed position relative to the automatic guided vehicle main body 20.

[0017] The swivel arm 30 is disposed on the upper surface side of the automatic guided vehicle body 20. The swivel arm 30 includes an arm upper surface portion 40, an arm lower surface portion 41 (see FIG. 5) disposed below the arm upper surface portion 40, and arm side surface portions 42 fixed to both sides of the arm upper surface portion 40 and the arm lower surface portion 41.

[0018] As shown in Fig. 5, a bearing member 43 is attached to the underside of the front end of the arm upper surface portion 40, and this bearing member 43 is attached to the upper end of a vertical rotating shaft 44 protruding from the top surface of the automatic guided vehicle body 20 so as to be rotatable in the horizontal direction. As a result, the rotating arm 30 is connected to the automatic guided vehicle body 20 so as to be rotatable in the horizontal direction about the rotating shaft 44. The rotating range of the rotating arm 30 is at least 90° in each direction to the left and right, based on a central axis along the front-to-rear direction of the automatic guided vehicle body 20. The axial direction of the rotating shaft 44 is the up-down direction which intersects with the direction of travel of the automatic guided vehicle body 20.

[0019] The swivel shaft 44 is attached to the AGV body 20 by being supported by a pair of upper and lower bearing members 45, 46, and supports the entire traction device 21 via the swivel arm 30. The swivel shaft 44 is located at the center between the axes of the pair of running wheels 22, and serves as the center when the AGV body 20 turns at a fixed position.

[0020] As shown in Figure 3, guide rails 47 that guide the vertical movement of the lifting arm 31 are attached to the outer surfaces of the rear ends of both arm side sections 42, and guide shafts 48 that are arranged vertically and parallel to the guide rails 47 are attached by upper and lower mounting members 49. A spring receiving member 50 attached to the lifting arm 31 is inserted into the guide shaft 48 so that it can move up and down. A spring 51 is arranged around the guide shaft 48 between the upper mounting member 49 and the spring receiving member 50. The spring 51 urges the lifting arm 31 downward relative to the pivot arm 30 via the spring receiving member 50, thereby urging the cam follower 34 attached to the lifting arm 31 toward the end cam 33 attached to the pivot arm 30.

[0021] The rotation position of the swivel arm 30 is detected by an encoder provided for the swivel arm 30. The encoder has the position where the swivel arm 30 is arranged on the central axis along the front-rear direction of the automatic guided vehicle body 20 as its origin (0 degrees).

[0022] The lifting arm 31 also includes a lifting frame 54 attached to the rear end of the swivel arm 30 so as to be movable up and down, and a lifting arm portion 55 fixed to the rear side of the lifting frame 54.

[0023] The lifting frame 54 has a rear frame portion 56 facing the rear end surface of the swivel arm 30 and side frame portions 57 on both sides facing both side surfaces of the swivel arm 30, and is provided with a generally U-shaped cross section. A plurality of rollers 58 are attached to the inner surfaces of the side frame portions 57 on both sides so as to sandwich the guide rail 47 of the swivel arm 30 from both sides, and the lifting arm 31 moves up and down in the vertical direction as the plurality of rollers 58 rotate along the guide rail 47. A spring receiving member 50 is connected to the side frame portions 57 on both sides of the lifting frame 54, and the lifting arm 31 is urged downward by a spring 51 via the spring receiving member 50. A support member 59 for supporting the cam follower 34 is fixed between the upper ends of the side frame portions 57 on both sides.

[0024] The lifting arm section 55 is provided in the shape of a square pillar and is fixed vertically to the rear frame section 56 of the lifting frame 54, with its lower end side located behind the automatic guided vehicle main body 20. The lifting arm section 55 is capable of rotating without coming into contact with the automatic guided vehicle main body 20 when the swivel arm 30 rotates.

[0025] The hook 32 is attached to the lower end of the rear surface of the lifting arm section 55 of the lifting arm 31. The hook 32 has a conical column or cylinder at the tip end and is installed vertically on a hook mounting member 62 attached to the lifting arm section 55. The hook 32 enters the connecting frame 14 of the connectable part 13 of the towed object 11 and is insertable into and detachable from the connecting hole 15 of the connectable part 13 from below. A positioning roller 63 is disposed on the underside of the hook mounting member 62 and enters the connecting frame 14 of the connectable part 13 of the towed object 11 to position the hook 32 in the left-right direction relative to the connecting hole 15, and a positioning roller 64 is disposed on the upper surface of the hook mounting member 62 and abuts against the front edge of the connecting frame 14 to position the hook 32 in the front-rear direction relative to the connecting hole 15.

[0026] The end cam 33 is installed on the upper surface of the swivel arm 30, toward the rear end away from the swivel shaft 44. The end cam 33 is cylindrical and has a cam rotation shaft 67 as its central axis, and has an annular cam surface 68 on one end surface, the annular cam surface 68 being centered on the cam rotation shaft 67. The end cam 33 rotates horizontally around the cam rotation shaft 67, which is in the vertical direction, with the cam surface 68 facing upward. The cam surface 68 has an inclined surface sandwiched between flat surfaces at the upper and lower ends so as to create a height difference depending on the rotation angle. As the contact point of the cam surface 68 with the cam follower 34 moves, the lifting arm 31 moves up and down via the cam follower 34, and the position of the hook 32 changes between a position where it engages with the towed object 11 and a position where it releases the towed object 11. That is, when the cam follower 34 is located on the plane of the lowest position of the cam surface 68, the lifting arm 31 is located at the lower end, and when the cam follower 34 is located on the plane of the highest position of the cam surface 68, the lifting arm 31 is located at the upper end. Note that the annular cam surface 68 may have a shape in which the entire surface of the cam surface 68 is a continuous ring in plan view, or the cam surface 68 may have a shape in which part of the cam surface 68 is annular.

[0027] The end cam 33 is supported on an end cam support base 69, and a cam rotation shaft member 70 coaxial with the cam rotation shaft 67 protruding from the underside of the end cam support base 69 is rotatably supported by a pair of bearing members 71 attached to the arm upper surface portion 40 and arm lower surface portion 41 of the swivel arm 30. A vertical load applied to the end cam 33 is supported by the swivel arm 30 via the end cam support base 69 and bearing members 71.

[0028] The cam follower 34 is also installed on the underside of the support member 59 of the lifting arm 31. The cam follower 34 has a roller 75 that is rotatable on a horizontal shaft 74, and both ends of the shaft 74 that passes through the roller 75 are supported by roller support members 76, which attach the cam follower 34 to the underside of the support member 59. The cam follower 34 is supported and placed on the cam surface 68 of the end cam 33, and the cam follower 34 supports the lifting arm 31 and the hook 32 attached to the lifting arm 31. The cam follower 34 rotates in the circumferential direction of the cam surface 68 of the end cam 33, and moves up or down while rotating following the cam surface 68 as the end cam 33 rotates, thereby raising or lowering the lifting arm 31.

[0029] The motor 35 is installed in an upright position on the upper surface of the swivel arm 30, between the end cam 33 and the swivel shaft 44. The motor 35 is formed to be long in the axial direction of the motor shaft 79, and the motor shaft 79 is arranged along the vertical direction, parallel to the cam rotation shaft 67 of the end cam 33. The motor 35 is installed on the upper surface of the swivel arm 30, with its lower end fixed to the upper surface of the arm lower surface portion 41 and its upper end protruding above the upper surface of the arm upper surface portion 40. The motor 35 is operated by power supplied from a battery included in the automaton guided vehicle body 20, under the control of a control device included in the automaton guided vehicle body 20.

[0030] The transmission mechanism 36 is disposed on the underside of the revolving arm 30. The transmission mechanism 36 is provided on the underside of the arm underside portion 41 with a pulley 82 attached to the cam rotation shaft member 70 which is the cam rotation shaft 67 of the end face cam 33, a pulley 83 attached to the output shaft 35a which is located on the motor shaft 79 of the motor 35 and is driven to rotate, and a timing belt 84 which is a transmission member wound around these pulleys 82 and 83. The transmission mechanism 36 may also be a gear mechanism using multiple gears, a chain, a magnet, or the like.

[0031] The positioning holding mechanism 37 also includes a positioning roller (positioning bearing) 87 as a positioning fitting member installed on the lifting arm 31, and a positioning member 88 (positioning guide) as a positioning fitted member installed on the automatic guided vehicle body 20. The positioning fitting member and the fitted member may be any member as long as they can be changed between a separated state and a fitted state.

[0032] The positioning roller 87 is installed on the front side of the lifting arm portion 55 of the lifting arm 31, at a height position between the lifting frame 54 and the hook 32. The positioning roller 87 is rotatable around an axis perpendicular to the front side of the lifting arm portion 55 in accordance with the rotation direction of the swivel arm 30.

[0033] The positioning member 88 is installed at the rear end of the upper surface of the automatic guided vehicle body 20. The positioning member 88 has a substantially V-shaped positioning groove 89 formed therein corresponding to the rotation direction of the swivel arm 30. The positioning groove 89 has inclined walls 90 on both sides that slope toward the center. The center position, which is the lowest part of the positioning groove 89, is located on the central axis along the front-to-rear direction of the automatic guided vehicle body 20, and when the positioning roller 87 is located at the tip of the positioning groove 89, the encoder of the swivel arm 30 indicates the origin (0 degrees).

[0034] When the lifting arm 31 is lowered at a predetermined rotation angle of the end cam 33, the positioning roller 87 fits into the positioning groove 89 of the positioning member 88, preventing unnecessary rotation or vibration of the swivel arm 30. At this time, even if there is some variation in the rotation position of the swivel arm 30, the positioning roller 87 is guided to the lowest part of the approximately V-shaped positioning groove 89, so that the rotation position of the swivel arm 30 is located on the central axis along the front-to-rear direction of the automatic guided vehicle body 20. Note that the positioning roller 87 may be configured to fit into the positioning groove 89 and rest on the positioning member 88, with a lower position of the cam surface 68 of the end cam 33 facing the cam follower 34 and the cam surface 68 of the end cam 33 moving away from the cam follower 34, thereby supporting the lifting arm 31 and the hook 32 attached to this lifting arm 31 with the positioning holding mechanism 37.

[0035] Next, the operation of the automatic guided vehicle 10 will be described.

[0036] FIG. 1 shows an automated guided vehicle 10 in a state before a towed object 11 is coupled to the automated guided vehicle 10, or in a state after the automated guided vehicle 10 has been released from the towed object 11. In FIG.

[0037] In this state, the hook 32 is at a height of a disconnection position lower than the connecting hole 15 of the connected part 13 of the towed object 11.

[0038] As shown in FIG. 5(a), when the hook 32 is at the height of the disconnection position, the end cam 33 is at a rotation position where the lower height position of the cam surface 68 is in contact with the cam follower .

[0039] The bias of the spring 51 keeps the cam follower 34 in contact with the cam surface 68 of the end cam 33 via the spring receiving member 50 and the lifting arm 31, and the hook 32 is kept in the disconnected position.

[0040] A positioning roller 87, which descends together with the lifting arm 31, engages with a positioning groove 89 of a positioning member 88, and the swivel arm 30 is positioned and held on the central axis along the front-to-rear direction of the automatic guided vehicle body 20.

[0041] To couple the towing device 21 of the automated guided vehicle 10 to the towed object 11, as shown in FIG. 1, the rear side of the towing device 21 of the automated guided vehicle 10 travels to a position facing the front side of the coupled part 13 of the towed object 11, and then retreats to approach the towed object 11, whereby the hook 32 enters the connecting frame 14 of the coupled part 13 and is positioned below the connecting hole 15.

[0042] The motor 35 operates, and the driving force from the motor 35 is transmitted to the end face cam 33 via the transmission mechanism 36, causing the end face cam 33 to rotate around the vertical cam rotation axis 67 in the first direction in which the height of the cam surface 68 increases relative to the cam follower 34.

[0043] As the end cam 33 rotates in the first direction, the height of the cam surface 68 with which the cam follower contacts gradually increases, causing the cam follower to rise, and the lifting arm 31 rises via the cam follower .

[0044] At this time, the cam follower 34 is biased toward the cam surface 68 of the end face cam 33 by the spring 51 via the lifting arm 31, so that the rise of the cam follower 34 can be reliably followed by the rise of the cam surface 68 of the end face cam 33.

[0045] The hook 32 rising together with the lifting arm 31 is inserted from below into the connecting hole 15 of the connected part 13 of the towed object 11 , and the hook 32 is connected to the connected part 13 of the towed object 11 .

[0046] As shown in Figure 5(b), the end cam 33 is rotated to a predetermined angle position, the hook 32 rises to a predetermined connecting position connected to the connected portion 13, and the positioning roller 87 moves above the positioning member 88, thereby stopping the motor 35.

[0047] The automated guided vehicle 10 moves forward and tows the towed object 11. When the automated guided vehicle 10 turns to turn along a curved travel path or to change direction by 90° or 180°, the swivel arm 30 turns relative to the automated guided vehicle body 20, enabling the automated guided vehicle 10 to turn.

[0048] After the towed object 11 is transported to a predetermined transport location, the towing device 21 of the automatic guided vehicle 10 is disconnected from the towed object 11. Fig. 6 shows a flowchart of the disconnection operation including the positioning operation of the swivel arm 30 of the tow device 21, and Figs. 7(a) to 7(d) show the uncoupling operation including the positioning operation of the swivel arm 31.

[0049] After the towed object 11 is transported to a predetermined transport location, the running wheel motors of the running wheels 22 on both sides of the automatic guided vehicle body 20 are driven to rotate in opposite directions (step S1), and the automatic guided vehicle body 20 rotates on the spot until the encoder of the swivel arm 30 reaches the origin (0 degrees).

[0050] When the encoder of the swivel arm 30 reaches the origin (0 degrees) and the swivel arm 30 returns to the predetermined angle (YES in step S2), the running wheel motor is stopped (step S3). As a result, the swivel arm 30 is positioned on the central axis along the front-to-rear direction of the AGV body 20, that is, the AGV body 20 stops with the positioning roller 87 of the lifting arm 31 facing above the positioning groove 89 of the positioning member 88 of the AGV body 20, as shown in FIG. 7(a).

[0051] The motor 35 for the end face cam 33 is driven (step S4), and the driving force from the motor 35 is transmitted to the end face cam 33 via the transmission mechanism 36, causing the end face cam 33 to rotate around the vertical cam rotation axis 67 toward a second direction in which the height of the cam surface 68 becomes lower relative to the cam follower 34, up to a predetermined first angle.

[0052] As the end face cam 33 rotates in the second direction, the height of the cam surface 68 with which the cam follower 34 comes into contact gradually decreases, causing the cam follower 34 to descend, and the lifting arm 31 to descend via the cam follower 34. At this time, the cam follower 34 is urged by the spring 51 via the lifting arm 31 toward the cam surface 68 of the end face cam 33, so that the descent of the cam follower 34 can be made to reliably follow the descent of the cam surface 68 of the end face cam 33.

[0053] When the end face cam 33 rotates to the first angle (YES in step S5), the motor 35 is stopped (step S6).

[0054] 7(b), when the end cam 33 has rotated to the first angle, the hook 32 of the lifting arm 31 drops downward from the connecting hole 15 of the connected part 13 of the towed object 11, and at least a part of the positioning roller 87 of the lifting arm 31 enters the positioning groove 89 of the positioning member 88 of the automatic guided vehicle body 20. In this state, the positioning roller 87 can move relatively within the width of the positioning groove 89 of the positioning member 88, and the swivel arm 30 can swivel with respect to the automatic guided vehicle body 20.

[0055] Thereafter, the running wheel motors of the running wheels 22 on both sides of the automatic guided vehicle body 20 are driven (step S7), and the automatic guided vehicle body 20 moves forward.

[0056] As the automatic guided vehicle body 20 moves forward, the hook 32 of the lifting arm 31 disengages from the coupled part 13 of the towed object 11, as shown in FIG. 7(c).

[0057] At this time, even if the unmanned transport vehicle main body 20 moves forward, at least a portion of the positioning roller 87 of the lifting arm 31 is inside the positioning groove 89 of the positioning member 88 of the unmanned transport vehicle main body 20, so the positioning roller 87 will not come out of the positioning groove 89 of the positioning member 88.

[0058] When the automated guided vehicle main body 20 has moved a predetermined distance (YES in step S8), the motor 35 for the end face cam 33 is driven (step S9), the driving force from the motor 35 is transmitted to the end face cam 33 via the transmission mechanism 36, and the end face cam 33 rotates around the vertical cam rotation axis 67 toward the second direction in which the height of the cam surface 68 becomes lower relative to the cam follower 34, to the next predetermined second angle.

[0059] The lifting arm 31 descends, and the positioning roller 87 of the lifting arm 31 abuts against the inclined wall 90 of the positioning groove 89 of the positioning member 88. When the positioning roller 87 abuts against one of the inclined walls 90 of the positioning groove 89 of the positioning member 88, the positioning roller 87 is guided along one of the inclined walls 90 to the center of the positioning groove 89, and the swivel arm 30 swivels.

[0060] When the end cam 33 has rotated to the second angle (YES in step S10), the motor 35 is stopped (step S11). When the end cam 33 has rotated to the second angle, the lifting arm 31 is lowered to the lower end, and the positioning roller 87 is positioned and held in contact with both inclined walls 90 of the positioning groove 89 of the positioning member 88, as shown in FIG. 7(d).

[0061] The lowering of the lifting arm 31 accompanying the rotation of the end face cam 33 to the second angle may be performed while the automatic guided vehicle body 20 is traveling, or may be performed after the automatic guided vehicle body 20 has stopped.

[0062] Incidentally, if the lifting arm 31 is lowered in one go to the lowering end while the swivel arm 30 is tilted relative to the automatic guided vehicle body 20, and the positioning roller 87 comes into contact with one of the inclined walls 90 of the positioning groove 89 of the positioning member 88 during the descent, the positioning roller 87 will move along the inclined wall 90 of the positioning groove 89 as the lifting arm 31 descends. This may cause the swivel arm 30 to swing, and the hook 32 may collide with the inner surface of the connecting frame 14 of the connectable part 13. As described above, by moving the automatic guided vehicle body 20 forward with the hook 32 removed from the connecting hole 15 of the connectable part 13 and then further lowering the lifting arm 31 to the lowering end, it is possible to prevent the hook 32 from colliding with the inner surface of the connecting frame 14 of the connectable part 13.

[0063] In the traction device 21 of the automated guided vehicle 10 configured as described above, the swivel arm 30 is provided with an end cam 33 that rotates horizontally around a vertical cam rotation axis 67 with the cam surface 68 facing upward, and the cam follower 34 attached to the lift arm 31 rests on the cam surface 68 of this end cam 33, allowing the end cam 33 to bear the load for supporting the lift arm 31. Therefore, a load is applied to the motor shaft 79 of the motor 35 attached to the swivel arm 30 only when the end cam 33 is rotated, but no load for supporting the weight of the lift arm 31 is applied, reducing the load applied to the motor shaft 79 of the motor 35 and extending the life of the motor 35.

[0064] Furthermore, since the upper surface side of the swivel arm 30 does not affect the rotation relative to the automatic guided vehicle body 20 and there are few space restrictions, by installing the end cam 33 and motor 35 on the upper surface side of this swivel arm 30, it is possible to make effective use of space and achieve an efficient layout configuration.

[0065] Furthermore, because the motor shaft 79 of the motor 35 is disposed in a vertical direction parallel to the cam rotation shaft 67 of the end face cam 33, the installation space for the motor 35 is smaller and the length of the swivel arm 30 can be shortened compared to when the motor shaft 79 is disposed horizontally along the longitudinal direction of the swivel arm 30. By shortening the length of the swivel arm 30, the load on the swivel shaft 44 to which the swivel arm 30 is attached can be reduced.

[0066] Furthermore, instead of directly supporting the end face cam 33 with the motor 35, a transmission mechanism 36 is provided to transmit driving force between the end face cam 33 and the motor 35, so that the load for supporting the lifting arm 31 is not applied to the motor shaft 79 of the motor 35.

[0067] In addition, since a spring 51 is provided that urges the lifting arm 31 downward relative to the swivel arm 30, the cam follower 34 installed on the lifting arm 31 is urged against the cam surface 68 of the end face cam 33 installed on the swivel arm 30, making it possible to ensure that the cam follower 34 follows the cam surface 68 of the end face cam 33.

[0068] Furthermore, a positioning and holding mechanism 37 is provided which positions and holds the rotation position of the swivel arm 30 relative to the AGV main body 20 via the lifting arm 31 which is lowered at a predetermined rotation angle of the end face cam 33, thereby limiting the rotation of the swivel arm 30, facilitating the connection operation of the hook 32 to the towed object 11, and preventing the swivel arm 30 from rotating when the AGV 10 is traveling without towing the towed object 11.

[0069] It should be noted that a cylindrical groove cam can also be used as the rotary cam in addition to the end face cam 33. In addition, a rotary cam can be used in which a downward recess is provided in part of the cam surface 68 and the cam follower 34 fits into this recess to position and hold the swivel arm 30.

[0070] Also, the towed object 11 may be provided with a hook 32, and the lifting arm 31 may be provided with an opening into which the hook 32 is inserted, or a gripping member or the like may be used instead of the hook 32. Therefore, the connecting member is not limited to the hook 32, but may include various structures that can achieve a connected state with the towed object 11. Note that the hook 32 may be oriented downward to connect the towed object 11 by lowering the lifting arm 31, and the towed object 11 may be released by raising the lifting arm 31.

[0071] Furthermore, the positioning and holding mechanism 37 is designed to have an upward opening so that it can exert a positioning and holding effect when the lifting arm 31 is at the lower end, but it can also be designed to have a downward opening so that it can exert a positioning effect when the lifting arm 31 is at the upper end.

[0072] 8(a) and 8(b), the vertical positional relationship between the hook 32 serving as the connecting part, the positioning roller 87 serving as the positioning fitting member, and the positioning member 88 serving as the positioning fitted member can be changed depending on the structure of the automatic guided vehicle body 20 and the position and structure of the connected part 13. FIG. 8(a) shows a case where the hook 32 faces downward, and FIG. 8(b) shows a case where the vertical positions of the positioning roller 87 and the positioning member 88 are reversed depending on the position of the connected part 13 of the towed object 11 and the structure of the automatic guided vehicle body 20. Also, as shown in FIG. 8(c), it is possible to install the positioning member 88 serving as the positioning fitted member on the lifting arm 31 side, and the positioning roller 87 serving as the positioning fitted member on the automatic guided vehicle body 20 side.

[0073] Furthermore, as shown in Figure 8(d), the positioning member 88 may have a groove 91 formed at the central position between the inclined walls 90 that are inclined toward the center, the groove 91 being deeper than the inclination angle of the inclined walls 90, thereby fixing the position of the positioning roller 87 at the groove 91.

[0074] Although the embodiment of the present invention and its modified examples have been described above, various combinations of configurations, partial omissions, substitutions and modifications are also possible. [Explanation of symbols]

[0075] 10 Automated Guided Vehicle 11 Traction 20 Automated guided vehicle body 21 Traction device 30 Swivel arm 31 Lifting arm 32 Hook, the connecting part 33 Rotating cam, end face cam 34 Cam follower 35 Rotating cam drive motor 35a output shaft 36 Transmission Mechanism 37 Positioning and holding mechanism 44 Swivel axis 51 Spring 67 Cam rotation shaft 68 Cam surface

Claims

1. A towing device connected to an automatic guided vehicle body that tows a towing object, a swivel arm connected to the automatic guided vehicle body so as to be rotatable about a vertical swivel axis that intersects with the traveling direction of the automatic guided vehicle body; a lifting arm that moves up and down relative to the pivoting arm and has a connecting portion that connects to the towed object and a cam follower; a rotary cam that is installed on the rotary arm so as to be rotatable about a vertical cam rotation axis, and has a cam surface that is formed in an annular shape about the cam rotation axis and supports the cam follower; a rotary cam drive unit that is installed on the pivot arm and that rotates the rotary cam, By rotating the rotary cam, the lifting arm is raised and lowered via the cam follower, and the position of the connecting portion changes between a position where it is connected to the towed object and a position where it is released from the towed object. A towing device characterized by:

2. The rotary cam and the rotary cam drive unit are installed on the upper surface side of the pivot arm.

2. The towing device according to claim 1.

3. the rotating cam is located on a rear end side of the rotating arm away from the rotating shaft, The rotary cam drive unit is located between the rotary cam and the pivot shaft.

3. A traction device according to claim 1 or 2.

4. A transmission mechanism is provided to transmit a driving force between the rotary cam and the rotary cam drive unit.

4. A traction device according to claim 1, wherein the traction device is a traction device.

5. the rotary cam drive unit has an output shaft that is disposed parallel to the cam rotary shaft and that rotates; The driving force of the output shaft is transmitted to the cam rotation shaft via a transmission mechanism.

4. A traction device according to claim 1, wherein the traction device is a traction device.

6. a spring that urges the lifting arm downward relative to the pivot arm so as to urge the cam follower toward the cam surface; 6. A traction device according to claim 1, wherein the traction device is a traction device.

7. a positioning and holding mechanism that positions and holds the rotation position of the swivel arm relative to the automatic guided vehicle via the lifting arm that has been lowered at a predetermined rotation angle of the rotary cam; 7. A traction device according to claim 1, wherein the traction device is a traction device.

8. the automatic guided vehicle body; a traction device according to any one of claims 1 to 7, which is installed on the automatic guided vehicle body; An unmanned transport vehicle comprising:

Images