Conveying assistance device

Abstract

To provide a transportation auxiliary device for enlarging a stroke quantity of a drive wheel while keeping a height dimension to be equal to that of a conventional device.SOLUTION: A transportation auxiliary device 1 is arranged between front wheels and rear wheels in a front and rear direction. The transportation auxiliary device includes: base members 71 fixed to a lower part of a bed; a first arm member 72R connected to the base member so as to rock around a first rocking shaft Ow1 extending in a right and left direction of the bed; a first mecanum wheel 21R supported by the first arm member and having a first axle 213R to be integrally rocked with the first arm member; and a first spring member 75R for energizing the rocking of the first arm member so as to press the first mecanum wheel against a transportation surface of the bed. The first spring member includes: one end part 751R to be connected to the first arm member; and an other end part 752R arranged on a front or rear side with respect to the one end part and connected to the base member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This disclosure relates to a transport assistance device. [Background technology]

[0002] For example, Patent Document 1 discloses a Mecanum wheel vehicle. This vehicle comprises a chassis, at least four Mecanum wheels, and coil springs that support each Mecanum wheel relative to the chassis.

[0003] According to the aforementioned Patent Document 1, each coil spring is interposed between the chassis and each Mecanum wheel, and is configured to act with a spring force component in a direction perpendicular to the ground. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 2018-504305 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The inventors of the present invention considered assisting in the transport of a bed equipped with casters by attaching drive wheels, such as Mecanum wheels, to the underside of the bed. In doing so, they considered using a spring member, such as the coil spring disclosed in Patent Document 1, to keep the drive wheels in close contact with the road surface of the transport path.

[0006] Furthermore, the inventors of this application conducted further studies and considered unitizing the aforementioned drive wheel and spring member and placing it between the front and rear wheels of a bed with casters.

[0007] However, when the device was positioned as described above, there was a possibility that the drive wheels might separate from the road surface or the contact between the drive wheels and the road surface might weaken when the vehicle moved from a flat road surface to a sloping road surface.

[0008] To alleviate such concerns, one could consider increasing the amount of extension and contraction of the spring member to increase the stroke amount of the drive wheel (especially the downward stroke). However, if the spring member is configured to extend and contract vertically, as in Patent Document 1, increasing the amount of extension and contraction of the spring member would lead to an increase in the size of the device in the height direction, which is undesirable.

[0009] The technology disclosed herein has been developed in view of the above, and its purpose is to increase the stroke amount of the drive wheels while maintaining the same height dimensions as conventional devices. [Means for solving the problem]

[0010] A first aspect of the present disclosure relates to a transport assist device positioned between the front and rear wheels in the front-rear direction of a castered bed equipped with a plurality of casters having front and rear wheels, in order to assist in the manual movement of the castered bed. The transport assist device comprises a base member fixed to the lower part of the bed; an arm member connected to the base member and swinging about a rotation axis extending in the left-right direction of the bed; a drive wheel supported by the arm member and having an axle that swings integrally with the arm member; and a spring member that biases the swinging of the arm member so as to press the drive wheel against the transport surface of the bed, wherein the spring member has one end connected to the arm member and the other end positioned either in front of or behind the one end and connected to the base member.

[0011] According to the first embodiment described above, a spring member for biasing the swing of the arm member is connected in a position aligned with the front-rear direction of the bed. With this position, the drive wheel strokes in the vertical direction while the spring member itself expands and contracts in the front-rear direction. By making the stroke direction of the drive wheel intersect with the expansion and contraction direction of the spring member, even if the amount of expansion and contraction of the spring member is increased to increase the stroke amount of the drive wheel, the height dimension can be kept the same as that of conventional devices.

[0012] Furthermore, according to a second aspect of the present disclosure, the base member may be composed of a pair of front and rear beam-like members that span between the side frames of the bed, the arm member may be connected to one of the pair of front and rear beam-like members, and the other end of the spring member may be connected to the other of the pair of front and rear beam-like members.

[0013] According to the second embodiment described above, the transport assist device can be further modularized by connecting an arm member and a spring member to a pair of beam-shaped members. By modularizing the device, it becomes easier to attach and detach it from the bed. This improves the usability of the transport assist device.

[0014] Furthermore, according to a third aspect of this disclosure, a drive wheel, a motor driven and connected to the drive wheel, and a housing box housing a controller for controlling the motor may be arranged between the pair of front and rear beam-like members.

[0015] According to the third embodiment described above, it becomes possible to further unitize the transport assistance device. This makes it easier to attach it to the bed.

[0016] Furthermore, according to a fourth aspect of this disclosure, the transport assist device may include a battery that supplies power to the motor and the controller, the battery being located outside the housing box, and the battery being configured to be detachable from the bed.

[0017] According to the fourth embodiment, by intentionally placing the battery outside the storage box, it becomes unnecessary to remove the storage box from the bed or open and close the storage box when replacing the battery. This improves the usability of the transport assistance device.

[0018] Further, according to a fifth aspect of the present disclosure, the spring member may be configured by a tension spring that contracts to pull in the arm member, and the arm member may constitute a bell crank mechanism with the spring member as the driving body and the axle as the driven body.

[0019] According to the fifth aspect, when the arm member constitutes a bell crank mechanism, it is advantageous for vertically stroking the axle by utilizing the biasing force of the spring member.

[0020] Further, according to a sixth aspect of the present disclosure, the axle may be disposed in front of or behind the rotation axis, the connecting portion between the one end portion of the spring member and the arm member may be disposed above the rotation axis, and in a side view along the left-right direction, the distance between the rotation axis and the axle may be longer than the distance between the rotation axis and the connecting portion.

[0021] According to the sixth aspect, when the arm member rotates around the rotation axis, the displacement amount of the axle with respect to the rotation axis becomes larger than the displacement amount of the connecting portion with respect to the rotation axis. Thereby, when the connecting portion is pulled in by the spring member to swing the arm member, the axle can be displaced more than the displacement amount of the connecting portion. This is effective in increasing the stroke amount of the drive wheel.

[0022] Furthermore, the connecting portion is disposed above the rotation axis. Therefore, relatively shortening the distance between the rotation axis and the connecting portion is effective for maintaining the same height dimension as the conventional device.

[0023] Further, according to a seventh aspect of the present disclosure, the arm member has a connecting portion connected to the one end portion of the spring member and a swinging end portion that supports the axle, the spring member is disposed so as to extend forward or backward in the front-rear direction from the other end portion as the fixed end toward the one end portion as the free end, while the arm member is disposed so as to extend in the front-rear direction in the opposite direction to the spring member from the connecting portion toward the swinging end portion.

[0024] According to the seventh embodiment, the arm member extends so as to fold back in the front-rear direction relative to the spring member. This configuration is advantageous in ensuring the stroke amount of the arm member and, consequently, the drive wheel, while maintaining dimensions equivalent to those of conventional devices in the front-rear direction.

[0025] Furthermore, according to an eighth aspect of this disclosure, the arm member and the spring member may be arranged such that they do not overlap with the drive wheel when the transport assist device is viewed from above.

[0026] According to the eighth embodiment described above, the drive wheel and the arm member or spring member are arranged so that they are not aligned in the vertical direction. This arrangement is advantageous in ensuring the vertical stroke of the drive wheel and in maintaining the transport assist device at the same height as conventional devices.

[0027] Furthermore, according to a ninth aspect of this disclosure, the transport assist device may be positioned in the front-to-back center of the lower part of the bed.

[0028] As mentioned above, when moving from a flat surface to a sloping surface, the drive wheels may separate from the surface or the contact between the drive wheels and the surface may weaken. Such problems become more pronounced when the transport assist device is positioned in the center of the front and rear of the caster-equipped bed. The configuration described in this disclosure is extremely useful under such circumstances. [Effects of the Invention]

[0029] As explained above, this disclosure makes it possible to increase the stroke amount of the drive wheels while maintaining the same height dimensions as conventional devices. [Brief explanation of the drawing]

[0030] [Figure 1] This is a side view illustrating the overall configuration of a transport assistance device and a bed with casters. [Figure 2]This is a bottom view illustrating the overall configuration of the transport assistance device and the bed with casters. [Figure 3] This is a perspective view illustrating the configuration of a transport assistance device. [Figure 4] This is a plan view illustrating the configuration of a transport assistance device. [Figure 5] This is a side view illustrating the configuration of a transport assistance device. [Figure 6] This is a front view illustrating the configuration of a transport assistance device. [Figure 7] This is a side view illustrating the mounting structure of a transport assist device. [Figure 8] This is a block diagram illustrating the configuration of the control system for a transport assistance device. [Figure 9] This is a schematic diagram illustrating the configuration of a transport assistance device. [Figure 10] This diagram illustrates the operation of a transport assistance device when crossing a step or obstacle. [Figure 11] This is a corresponding diagram to Figure 9 illustrating a conventional transport assistance device. [Figure 12] This diagram illustrates an example of a conventional transport assist device getting stuck. [Modes for carrying out the invention]

[0031] The embodiments of this disclosure will be described below with reference to the drawings.

[0032] Figure 1 is a side view illustrating the overall configuration of the transport assist device 1 and the wheeled bed 10, and Figure 2 is a bottom view illustrating the overall configuration of the transport assist device 1 and the wheeled bed 10.

[0033] Furthermore, Figure 3 is a perspective view illustrating the configuration of the transport assist device 1, Figure 4 is a plan view illustrating the configuration of the transport assist device 1, and Figure 5 is a side view illustrating the configuration of the transport assist device 1. Additionally, Figure 6 is a front view illustrating the configuration of the transport assist device 1, and Figure 7 is a diagram illustrating the mounting structure of the transport assist device 1.

[0034] Furthermore, Figure 8 is a block diagram illustrating the configuration of the control system of the transport assist device 1, and Figure 9 is a schematic diagram illustrating the configuration of the transport assist device. Also, Figure 10 is a diagram illustrating the operation of the transport assist device 1 when crossing a step, Figure 11 is a diagram corresponding to Figure 9 illustrating a conventional transport assist device 101, and Figure 12 is a diagram illustrating the conventional transport assist device 101 crossing a step.

[0035] The transport assist device 1 is attached to the object, a wheeled bed (hereinafter simply referred to as "bed") 10. This transport assist device 1 is a device for assisting the manual movement of the bed 10.

[0036] As shown in Figures 1 and 2, the bed 10 according to this embodiment is equipped with a plurality of casters 14, including front wheels 14F and rear wheels 14B, and is intended to be used, for example, as a medical bed.

[0037] Hereinafter, the longitudinal direction of the bed 10, that is, the direction in which a person lies on the bed 10, will be referred to as the "front-to-back direction" or "longitudinal direction," the direction toward the feet along that front-to-back direction will be referred to as "front," and the direction toward the head of the bed will be referred to as "back."

[0038] Similarly, the shorter side of the bed 10, that is, the direction perpendicular to the front-to-back direction on the horizontal plane, is defined as the "left-to-right direction" or "lateral direction." The direction toward the depth side of the page in Figure 1 along this left-to-right direction is defined as "right," and the direction toward the front side of the page in Figure 1 is defined as "left" (see Figure 2 for details). Here, "left-to-right direction" refers to the left-to-right direction when viewed from the rear to the front. In the following description, "lateral movement" refers to movement along this left-to-right direction. The left-to-right direction (lateral direction) can also be defined as the direction perpendicular to the front-to-back direction and extending along the transport surface (the floor surface on which the bed 10 travels) F.

[0039] The bed 10 is supported by the transporter 100. In the illustrated example, the bed 10 is supported at one end in the front-rear direction (for example, the rear end). The transport assist device 1 operates to assist the manual movement of the bed 10, which is supported by the transporter 100.

[0040] As shown in Figure 1, the bed 10 comprises a bed frame 11 on which a mattress (not shown) is placed, a frame 12 that supports the bed frame 11 from below, a lifting mechanism 13 that raises and lowers the bed frame 11 relative to the frame 12, and a plurality of casters 14 (four in the illustrated example) arranged on the underside of the bed 10. When used as a medical bed, the bed 10 will have a weight of, for example, between 60 kg and 300 kg.

[0041] Here, the bed body 11 includes a headboard 11h positioned on the rear end side of the bed 10, a footboard 11f positioned on the front end side opposite to the rear end side in the front-rear direction, and side rails 11s positioned on both the left and right sides of the bed 10.

[0042] Of these, the headboard 11h is supported from the rear by the transporter 100 in order to move the bed 10 by hand. The headboard 11h functions as a support part to which force is applied by the transporter 100. Components such as handles and grips may be attached to the headboard 11h or integrated with the headboard 11h, and these components may also be used as support parts. The footboard 11f, side rails 11s, etc. may also be supported.

[0043] Furthermore, as shown in Figure 2, frame 12 is configured in a rectangular frame shape, with its four sides being composed of a front frame 12F, a right frame 12R, a left frame 12L, and a rear frame 12B.

[0044] Here, the front frame 12F is positioned at the front of the bed 10 and extends along the left-right direction. The right frame 12R is positioned to the right of the bed 10 and extends along the front-back direction. The left frame 12L is positioned to the left of the bed 10 and extends along the front-back direction. The rear frame 12B is positioned at the rear of the bed 10 and extends along the left-right direction.

[0045] Furthermore, as shown in Figures 1 and 2, the front wheels 14F and rear wheels 14B that make up the multiple casters 14 are positioned at the four corners of the underside of the bed 10. There are two front wheels 14F and two rear wheels 14B arranged along the left-right direction. The multiple casters 14 support the frame 12, the lifting section 13, and the bed body 11 with respect to the transport surface F.

[0046] Each caster 14 is a so-called free caster and has a mounting portion 14a fixed to the underside of the bed 10, a fork portion 14b that can pivot around a pivot axis Oc relative to the mounting portion 14a, and a wheel 14c that is rotatably supported by the fork portion 14b. The pivot axis Oc of each fork portion 14b extends along the vertical direction (the height direction of the bed 10). The axis of rotation of each wheel 14c extends along the horizontal plane. This axis of rotation is tilted in the left-right direction as the fork portion 14b pivots relative to the mounting portion 14a.

[0047] The transport assist device 1 is positioned between the front wheels 14F and the rear wheels 14B in the front-rear direction of the bed 10 to assist in the manual movement of the bed 10. More specifically, the transport assist device 1 is positioned in the front-rear center of the lower part of the bed 10. Note that "positioned in the front-rear center" here refers to the range R between the front and rear ends of the transport assist device 1, as shown in Figure 2. fb Inside, the front-to-back center position P of bed 10. c It means that the situation has subsided.

[0048] More specifically, the transport assist device 1 is positioned to bridge the middle section in the front-rear direction of the right frame 12R and the middle section in the front-rear direction of the left frame L. In the front-rear direction, the transport assist device 1 is positioned between the front wheels 14F and the rear wheels 14B, and in the left-right direction, it is positioned in the center of the bed 10.

[0049] As shown in Figures 1 to 8, the transport assist device 1 comprises a storage box 6, a mounting bracket 7, first and second Mecanum wheels 21R and 21L as drive wheels, first and second motors 22R and 22L, a battery 3, a controller 4, and a 6-axis sensor 5 (the first and second motors 22R and 22L, and the 6-axis sensor 5 are shown only in Figure 8). Hereafter, of the first and second Mecanum wheels 21R and 21L, the first Mecanum wheel 21R will be positioned on the right side and the second Mecanum wheel 21L will be positioned on the left side.

[0050] Of these elements, the controller 4 and the 6-axis sensor 5 are housed in a housing box 6, while the battery 3, mounting bracket 7, first and second Mecanum wheels 21R, 21L, and first and second motors 22R, 22L are located outside the housing box 6.

[0051] The first and second Mecanum wheels 21R and 21L are mounted on the lower part (bottom) of the bed 10, as shown in Figures 1 and 2. The first and second Mecanum wheels 21R and 21L are in contact with the conveying surface F of the bed 10 (see Figures 1 and 9 for the conveying surface F). The first and second Mecanum wheels 21R and 21L are positioned behind the front wheel 14F and in front of the rear wheel 14B. In this embodiment, the first and second Mecanum wheels 21R and 21L are arranged side by side in the left-right direction, which is the shorter direction, as shown in Figure 2.

[0052] More specifically, as shown in Figures 3 to 5, the first Mecanum wheel 21R includes a first axle 213R that rotates around a first rotation axis Oy1, a first wheel body 211R that rotates integrally with the first axle 213R, and a plurality of first barrel-shaped rollers 212R arranged along the outer circumference of the first wheel body 211R, each rotating around a first inclined axis Or that is inclined with respect to the first rotation axis Oy1.

[0053] On the other hand, the second Mecanum wheel 21L includes a second axle 213L that rotates around a second rotation axis Oy2, a second wheel body 211L that rotates integrally with the second axle 213L, and a plurality of second barrel-shaped rollers 212L arranged along the outer circumference of the second wheel body 211L, each rotating around a second inclination axis Ol that is inclined in a direction different from the first inclination axis Or with respect to the second rotation axis Oy2.

[0054] Here, the first and second rotation axes Oy1 and Oy2 both extend in the left-right direction. The first tilt axis Or is tilted so as to be symmetric with respect to the second tilt axis Ol with respect to the front-back direction as the reference (see the axis of symmetry Os in Figure 4). In other words, the first tilt axis Or and the second tilt axis Ol extend so as to be mirror-symmetric with respect to a plane that extends in the vertical and front-back directions, which is the mirror plane.

[0055] Furthermore, as shown in Figure 4 when viewed from above (plan view), the first and second inclination axes Or and Ol extend from the inside to the outside in the left-right direction (from the center in the left-right direction to the right or left) as they move from the rear to the front along the front-back direction.

[0056] More specifically, the inclination angle θr of the first inclination axis Or with respect to the first rotation axis Oy1 is set to 45° in a plan view. Similarly, the inclination angle θl of the second inclination axis Ol with respect to the second rotation axis Oy2 is also set to 45° in a plan view. Note that the inclination direction and inclination angle of each barrel-shaped roller 212R, 212L are not limited to these examples. For example, the entire conveying assist device 1 may be rearranged from the state illustrated in Figure 2 to a state rotated by a predetermined angle around the z-axis extending in the vertical direction.

[0057] Furthermore, as will be described later, the first and second Mecanum wheels 21R and 21L are interconnected via the base member 71 shown in Figure 3, etc. Therefore, the first and second Mecanum wheels 21R and 21L can move integrally in the longitudinal and lateral directions, and can rotate integrally around a pivot axis perpendicular to the horizontal plane.

[0058] The first and second motors 22R and 22L are driven and coupled to the first and second Mecanum wheels 21R and 21L, respectively. Specifically, the first and second motors 22R and 22L are each configured as so-called three-phase DC brushless motors. Both the first and second motors 22R and 22L are electrically connected to a controller 4 and are controlled by this controller 4.

[0059] The first and second motors 22R and 22L are supplied with a motor current corresponding to the torque load during their respective rotations. The rotational speed of the first and second motors 22R and 22L, as well as forward and reverse rotation, can be switched via the motor current.

[0060] The first motor 22R is connected to the first Mecanum wheel 21R so as to transmit driving force (torque). The second motor 22L is connected to the second Mecanum wheel 21L so as to transmit driving force (torque).

[0061] When the first motor 22R rotates, its driving force is transmitted, causing the first Mecanum wheel 21R to rotate. Similarly, when the second motor 22L rotates, its driving force is transmitted, causing the second Mecanum wheel 21L to rotate.

[0062] In this embodiment, the first Mecanum wheel 21R rotates forward when the first motor 22R is rotated forward, and the first Mecanum wheel 21R rotates backward when the first motor 22R is rotated backward. Similarly, in this embodiment, the second Mecanum wheel 21L rotates forward when the second motor 22L is rotated forward, and the second Mecanum wheel 21L rotates backward when the second motor 22L is rotated backward (see also Figure 5).

[0063] The first motor 22R is built into the first Mecanum wheel 21R, and the second motor 22L is built into the second Mecanum wheel 21L. By integrating the first and second motors 22R and 22L in this way, the entire transport assist device 1 can be simplified and made more compact.

[0064] Battery 3 supplies power to the first and second motors 22R, 22L and the controller 4. In this embodiment, battery 3 is composed of, for example, a lithium-ion battery. Battery 3 is located outside the housing box 6, for example, below the frame 12. This battery 3 is configured to be detachable from the bed 10. This allows battery 3 to be removed and charged without removing the entire transport assist device 1 from the bed 10.

[0065] The controller 4 controls the first and second motors 22R and 22L based on electrical signals input from the 6-axis sensor 5, etc. This controller 4 has a CPU, memory, and input / output bus, and is composed of, for example, a control board.

[0066] The controller 4 determines the direction and magnitude of the force (external force) applied by the carrier 100 based on electrical signals input from the 6-axis sensor 5, etc. Based on this determination, the controller 4 calculates the commanded rotational speeds for the first and second motors 22R and 22L respectively, and drives the first and second motors 22R and 22L to achieve those commanded rotational speeds. As the controller 4 drives the first and second motors 22R and 22L, the first and second Mecanum wheels 21R and 21L rotate forward and / or backward.

[0067] In this process, by adjusting the rotation direction and rotation speed of the first and second Mecanum wheels 21R and 21L, thrust can be generated in the direction of the applied external force. This thrust can assist in the manual movement of the bed 10.

[0068] The storage box 6 is assembled to a mounting bracket 7 together with the first and second Mecanum wheels 21R and 21L, and is attached to the underside of the bed 10 via this mounting bracket 7. The mounting bracket 7 is detachable from the underside of the bed 10. In other words, the transport assist device 1 according to this embodiment can be retrofitted to the bed 10 and can be removed as needed.

[0069] As shown in Figures 2 to 7, the mounting fixture 7 according to this embodiment includes a base member 71, first and second arm members 72R, 72L, first and second spring members 75R, 75L, and first and second brackets 76R, 76L.

[0070] Furthermore, the first arm member 72R, the first spring member 75R, and the first bracket 76R, and the second arm member 72L, the second spring member 75L, and the second bracket 76L are configured to be mirror-symmetric with respect to a plane passing through the symmetry axis Os in Figure 4, similar to the relationship between the first Mecanum wheel 21R and the second Mecanum wheel 21L.

[0071] As shown in Figures 2, 6, and 7, the base member 71 is fixed to the underside of the bed 10 via a base bracket 79. This base member 71 is composed of a pair of front and rear beam-like members. The base member 71, composed of the pair of beam-like members, spans between the side frames of the bed 10 (between the right frame 12R and the left frame 12L), as shown in Figure 2. Hereinafter, the beam-like member located on the front side of the pair of front and rear beam-like members will be referred to as the front base member 71f, and the beam-like member located on the rear side will be referred to as the rear base member 71b.

[0072] The front base member 71f and the rear base member 71b are positioned with a gap between them in the front-rear direction, and each spans the front-rear center of the right frame 12R and the front-rear center of the left frame 12L, respectively. As shown in Figures 3 to 5, the front base member 71f and the rear base member 71b are positioned at approximately the same height and are parallel to each other in the horizontal direction.

[0073] The base bracket 79 attaches the front base member 71f and the rear base member 71b to the right frame 12R and the left frame 12L. The base bracket 79 is detachable from the right frame 12R and the left frame 12L. In this embodiment, the front base member 71f and the rear base member 71b are located below the right frame 12R and the left frame 12L.

[0074] Furthermore, as shown in Figure 4, the first and second Mecanum wheels 21R, 21L, the first and second motors 22R, 22L, and the housing box 6 are arranged between the front base member 71f and the rear base member 71b, which are a pair of beam-like members.

[0075] The first and second arm members 72R and 72L, which function as arm members, are each connected to the base member 71. Of the first and second arm members 72R and 72L, the first arm member 72R, located on the right side in Figures 3 and 4, swings around a first pivot axis (rotation axis) Ow1 that extends in the left-right direction. Similarly, the second arm member 72L, located on the left side in Figures 3 and 4, swings around a second pivot axis (rotation axis) Ow2 that also extends in the left-right direction. As shown in Figure 4, in this embodiment, the first pivot axis Ow1 and the second pivot axis Ow2 are coaxial.

[0076] More specifically, the first and second arm members 72R and 72L are composed of plate-shaped members extending in the front-rear and up-down directions. More specifically, the first and second arm members 72R and 72L are formed such that their dimensions in the front-rear direction are longer than their dimensions in the up-down direction.

[0077] More specifically, the first and second arm members 72R and 72L in this embodiment, as shown in Figure 3, each have a long side extending in the front-rear direction and a short side extending in the up-down direction, and are formed in an L-shape when laid on their side.

[0078] Furthermore, both the first and second arm members 72R and 72L are connected to one of the front base member 71f and the rear base member 71b (in this embodiment, the rear base member 71b).

[0079] Furthermore, as shown in Figure 3, the center position of the first pivot axis Ow1 is located behind the front end of the first arm member 72R and below the upper end of the first arm member 72R. In this embodiment, the first pivot axis Ow1 is located at the corner where the long side and short side intersect when the first arm member 72R is considered as an L-shape. The front end of the first arm member 72R supports the first axle 213R and functions as a pivot end that is displaced more than other parts when the first arm member 72R pivots. Hereinafter, this will be referred to as the "first pivot end 722R" (shown only in Figure 9).

[0080] Similarly, the center position of the second pivot axis Ow2 is located behind the front end of the second arm member 72L and below the upper end of the second arm member 72L, as shown in Figure 3. In this embodiment, the second pivot axis Ow2 is located at the corner where the long side and short side intersect when the second arm member 72L is considered as an L-shape. The front end of the second arm member 72L supports the second axle 213L and functions as a pivot end that is displaced more than other parts when the second arm member 72L pivots. Hereinafter, this will be referred to as the "second pivot end 722L" (shown only in Figure 9).

[0081] Furthermore, the first pivot shaft Ow1 and the second pivot shaft Ow2 are positioned between the front base member 71f and the rear base member 71b in the front-rear direction, and are positioned at approximately the same height as the front base member 71f and the rear base member 71b in the vertical direction. As shown in Figures 3 and 4, the first Mecanum wheel 21R is supported on the first arm member 72R. More specifically, the first Mecanum wheel 21R is supported at the front end of the first arm member 72R via the first axle 213R. This support allows the first axle 213R to swing integrally with the first arm member 72R.

[0082] In particular, in this embodiment, the first axle 213R, and by extension the first rotation axis Oy1 which serves as its center of rotation, is positioned in front of the first and second oscillating axes Ow1 and Ow2, and behind the front base member 71f, in the longitudinal direction. Alternatively, the first axle 213R may be positioned behind the first and second oscillating axes Ow1 and Ow2, and in front of the rear base member 71b.

[0083] Similarly, as shown in Figures 3 and 4, the second arm member 72L supports the aforementioned second Mecanum wheel 21L. More specifically, the second Mecanum wheel 21L is supported at the front end of the second arm member 72L via the second axle 213L. This support allows the second axle 213L to swing integrally with the second arm member 72L.

[0084] In particular, in this embodiment, the second axle 213L, and by extension the second rotation axis Oy2 which serves as its center of rotation, is positioned in front of the first and second oscillating axes Ow1 and Ow2, and behind the front base member 71f, in the longitudinal direction. Alternatively, the second axle 213L may be positioned behind the first and second oscillating axes Ow1 and Ow2, and in front of the rear base member 71b.

[0085] As shown in Figures 9 and 10, the first spring member 75R biases the oscillation of the first arm member 72R so as to press the first Mecanum wheel 21R against the conveying surface F. This oscillation is configured to cause the front end of the first arm member 72R to pivot downward. In this embodiment, the first spring member 75R is composed of a tension spring that contracts to pull in the first arm member 72R, particularly the upper end of the first arm member 72R.

[0086] Returning to Figures 3 to 5, as shown in these figures, the first spring member 75R has one end 751R connected to the first arm member 72R, and the other end 752R positioned either in front of or behind the one end 751R and connected to the base member 71. The first spring member 75R extends diagonally downward along the front-rear direction from the one end 751R to the other end 752R. The one end 751R of the first spring member 75R functions as the free end of the first spring member 75R. The other end 752R of the first spring member 75R functions as the fixed end of the first spring member 75R.

[0087] In this embodiment, one end 751R of the first spring member 75R is formed by the rear end of the first spring member 75R. This end 751R is connected to the upper end of the first arm member 72R. Hereinafter, this upper end will be referred to as the "first connecting part" and will be given the reference numeral "721R" (see Figures 3 and 9). As shown in Figure 3, the first connecting part 721R in this embodiment is positioned above the first pivot shaft Ow1 and the second pivot shaft Ow2, which serve as rotation axes.

[0088] On the other hand, the other end 752R of the first spring member 75R is formed by the front end of the first spring member 75R, which is positioned in front of the one end 751R. This other end 752R is connected to the other of the front base member 71f and the rear base member 71b (in this embodiment, the front base member 71f). At that time, the other end 752R is connected via a first bracket 76R fixed to the front base member 71f. The connection position between the first spring member 75R and the first bracket 76R is lower than the connection position between the first spring member 75R and the first arm member 72R.

[0089] Furthermore, as shown in Figure 4, the first arm member 72R and the first spring member 75R are positioned so as not to overlap with the first Mecanum wheel 21R when the transport assist device 1 is viewed from above. As shown in the same figure, the first arm member 72R and the first spring member 75R are positioned between the first Mecanum wheel 21R and the storage box 6 in the left-right direction. The first Mecanum wheel 21R is positioned to the right of the first arm member 72R, the first spring member 75R and the storage box 6.

[0090] Similarly, as shown in Figure 9, the second spring member 75L biases the oscillation of the second arm member 72L so as to press the second Mecanum wheel 21L against the conveying surface F. This oscillation is configured to cause the front end of the second arm member 72L to pivot downward. In this embodiment, the second spring member 75L is composed of a tension spring that contracts to pull in the upper end of the second arm member 72L, particularly the second arm member 72L.

[0091] Returning to Figures 3 to 5, as shown in these figures, the second spring member 75L has one end 751L connected to the second arm member 72L, and the other end 752L positioned either in front of or behind the one end 751L and connected to the base member 71. The second spring member 75L extends diagonally downward along the front-rear direction from the one end 751L to the other end 752L. The one end 751L of the second spring member 75L functions as the free end of the second spring member 75L. The other end 752L of the second spring member 75L functions as the fixed end of the second spring member 75L.

[0092] In this embodiment, one end 751L of the second spring member 75L is formed by the rear end of the second spring member 75L. This end 751L is connected to the upper end of the second arm member 72L. Hereinafter, this upper end will be referred to as the "second connecting part" and will be given the reference numeral "721L" (see Figures 3 and 9). As shown in Figure 3, the second connecting part 721L in this embodiment is positioned above the first pivot shaft Ow1 and the second pivot shaft Ow2, which serve as rotation axes.

[0093] On the other hand, the other end 752L of the second spring member 75L is formed by the front end of the second spring member 75L, which is positioned in front of the one end 751L. This other end 752L is connected to the other of the front base member 71f and the rear base member 71b (in this embodiment, the front base member 71f). 752L These are connected via a second bracket 76L fixed to the front base member 71f. The connection position between the second spring member 75L and the second bracket 76L is lower than the connection position between the second spring member 75L and the second arm member 72L.

[0094] Furthermore, as shown in Figure 4, the second arm member 72L and the second spring member 75L are positioned so as not to overlap with the second Mecanum wheel 21L when the transport assist device 1 is viewed from above. As shown in the same figure, the second arm member 72L and the second spring member 75L are positioned between the second Mecanum wheel 21L and the storage box 6 in the left-right direction. The second Mecanum wheel 21L is positioned to the left of the second arm member 72L, the second spring member 75L, and the storage box 6.

[0095] As shown in Figure 9, the first arm member 72R can be considered to constitute a first bell crank mechanism B1 with the first spring member 75R as the driving body and the first axle 213R as the driven body. That is, when one end 751R of the first spring member 75R pulls the first connecting portion 721R, the first arm member 72R is biased to swing around the first pivot axis Ow1. This bias acts in a direction that presses the first axle 213R against the conveying surface F, as shown by arrow A1 in Figure 9. This bias allows the first Mecanum wheel 21R to be pressed against the conveying surface F.

[0096] Furthermore, in relation to the configuration of the first bell crank mechanism B1, in a side view along the left-right direction, the distance L1 between the first pivot axis Ow1 and the front end of the first arm member 72R (more specifically, the distance between the first pivot axis Ow1, the first axle 213R and the first rotation axis Oy1) is longer than the distance L2 between the first pivot axis Ow1 and the first connecting portion 721R.

[0097] Furthermore, the first spring member 75R is arranged to extend forward or backward (towards the rear in this embodiment) in the front-rear direction from the other end 752R, which is a fixed end, toward the one end 751R, which is a free end. On the other hand, the first arm member 72R extends in the opposite direction to the first spring member 75R (forward in this embodiment) in the front-rear direction from its first connecting portion 721R toward the first swinging end 722R.

[0098] The first arm member 72R and the first spring member 75R function as a suspension. This function allows the conveyor to easily overcome steps on the conveying surface F. For example, as shown in Figure 10, when overcoming a step on the conveying surface F, the first arm member 72R rotates in the direction opposite to the biasing force indicated by arrow A1 (away from the conveying surface F). At that time, since the biasing force is still acting, contact between the first Mecanum wheel 21R and the conveying surface F is maintained.

[0099] The above explanation also applies to the second arm member 72L. The second arm member 72L can be considered to constitute a second bell crank mechanism B2 with the second spring member 75L as the driving body and the second axle 213L as the driven body. The biasing direction in this bell crank mechanism B2 is the same as the biasing direction for the first arm member 72R.

[0100] Furthermore, in relation to the configuration of the second bell crank mechanism B2, in a side view along the left-right direction, the distance L1 between the second pivot axis Ow2 and the front end of the second arm member 72L (more specifically, the distance between the second pivot axis Ow2, the second axle 213L, and the second rotation axis Oy2) is longer than the distance L2 between the second pivot axis Ow2 and the second connecting portion 721L in a side view.

[0101] Furthermore, the second spring member 75L is arranged to extend forward or backward (towards the rear in this embodiment) in the front-rear direction from the other end 752L, which is the fixed end, toward the one end 751L, which is the free end. On the other hand, the second arm member 72L extends in the opposite direction to the second spring member 75L (forward in this embodiment) in the front-rear direction from its second connecting portion 721L toward the second swinging end 722L.

[0102] As shown in Figure 11, in conventionally known transport assist devices 101, the drive wheels 121 have been considered to be pressed against the transport surface F by a spring member 175 that extends in the vertical direction.

[0103] Furthermore, the inventors of the present invention conducted further studies and considered arranging a unitized transport assist device 101 between the front wheels 14F and the rear wheels 14B of the bed 10 (see Figure 12).

[0104] However, when the transport assist device 101 is configured and arranged as shown in Figures 11 and 12, the flat road surface F f From the sloping road surface F s When the wheel drives onto the road surface, as shown in Figure 12, the drive wheel 121 is on the road surface (especially a flat road surface F) f and a sloping road surface F s There was a possibility that the wheel would move away from the boundary with the road surface, or that the contact between the drive wheel 121 and the road surface would weaken.

[0105] To alleviate these concerns, one could consider increasing the amount of extension and contraction of the spring member 175, thereby increasing the stroke amount of the drive wheel 121 (especially the downward stroke). However, if the spring member 175 is configured to extend and contract vertically as shown in Figures 11 and 12, increasing the amount of extension and contraction of the spring member 175 would lead to an increase in the size of the transport assist device 101 in the height direction, which is undesirable.

[0106] In contrast, according to the above embodiment, the first spring member 75R for biasing the swing of the first arm member 72R is connected in a position aligned with the front-rear direction of the bed 10 (see Figures 9 and 10, etc.). With this position, the first Mecanum wheel 21R, which acts as a drive wheel, strokes in the vertical direction, while the first spring member 75R itself expands and contracts in the front-rear direction. By making the stroke direction of the first Mecanum wheel 21R intersect with the expansion and contraction direction of the first spring member 75R, even if the amount of expansion and contraction of the first spring member 75R is increased to increase the stroke amount of the first Mecanum wheel 21R, it becomes possible to maintain the same height dimension as the conventional transport assist device 101.

[0107] Furthermore, as explained using Figures 3 to 5, the transport assist device 1 can be further modularized by connecting the first arm member 72R and the first spring member 75R to the base member 71, which is composed of a pair of beam-like members. By modularizing the device, it becomes easier to attach and detach it from the bed 10. This improves the usability of the transport assist device 1.

[0108] Furthermore, as shown in Figure 4, by arranging the first and second Mecanum wheels 21R, 21L, the first and second motors 22R, 22L, and the storage box 6 between the front base member 71f and the rear base member 71b, it becomes possible to further unitize the transport assist device 1. This makes it easier to attach to the bed 10.

[0109] Furthermore, as shown in Figure 2, by intentionally placing the battery 3 outside the storage box 6, it becomes unnecessary to remove the storage box 6 from the bed 10 or open and close the storage box 6 when replacing the battery 3. This improves the usability of the transport assistance device 1.

[0110] Furthermore, as shown in Figures 9 and 10, the first arm member 72R constitutes the bell crank mechanism B1, which is advantageous in using the biasing force of the first spring member 75R to stroke the first axle 213R up and down.

[0111] Also, as shown in FIG. 4, the first mecanum wheel 21R and the first arm member 72R or the first spring member 75R are arranged so as not to be aligned in the vertical direction. By arranging them in this way, it is possible to secure the vertical stroke of the first mecanum wheel 21R and it is advantageous in keeping the height dimension of the transport assist device 1 the same as that of the conventional device.

[0112] Also, as shown in FIG. 9, in a side view, the distance L1 between the first swing axis Ow1 and the first axle 213R is longer than the distance L2 between the first swing axis Ow1 and the first connection portion 721R.

[0113] By configuring in this way, when the first arm member 72R rotates around the first swing axis Ow1, the displacement amount of the first axle 213R with respect to the first swing axis Ow1 (particularly, the displacement amount in the vertical direction) is larger than the displacement amount of the first connection portion 721R with respect to the first swing axis Ow1 (particularly, the displacement amount in the front-rear direction). Thereby, when the first spring member 75R pulls in the first connection portion 721R to swing the first arm member 72R, the first axle 213R can be displaced more than the displacement amount of the first connection portion 721R. This is effective in increasing the stroke amount of the first mecanum wheel 21R.

[0114] Also, as shown in FIG. 9, the first arm member 72R extends so as to fold back in the front-rear direction with respect to the first spring member 75R. By configuring in this way, while securing the stroke amount of the first arm member 72R, and thus the first mecanum wheel 21R, it is advantageous in keeping the dimension in the front-rear direction the same as that of the conventional transport assist device 101.

[0115] Also, as described using FIG. 12, when getting onto the sloped road surface F f from the flat road surface F s as shown in FIG. 12, the drive wheel 121 separates from the road surface F f ,F s and the drive wheel 121 and the road surface F f,F s The contact with the bed may become weaker. This problem becomes more pronounced when the transport assist device 1 is positioned in the center of the front-to-back of the bed 10. The configuration according to the above embodiment is extremely useful under such circumstances.

[0116] <Other Embodiments> In the above embodiment, a configuration using first and second Mecanum wheels 21R and 21L as drive wheels was disclosed, but such a configuration is not essential. This disclosure can also be applied to drive wheels other than Mecanum wheels, such as omniwheels. The number of drive wheels is not limited to two. For example, if Mecanum wheels are used as in this embodiment, the number may be four, or if omniwheels are used, the number may be three or four. Furthermore, the number of motors may be changed according to the number of drive wheels. [Explanation of Symbols]

[0117] 1. Conveying assistance device 10 beds (beds with casters) 12 frames 12R Right frame (side frame) 12L Left frame (side frame) 14F Front wheels (casters) 14B Rear wheel (caster) 21R 1st Mecanum Wheel (Drive Wheel) 213R 1st axle (axle) 21L Second Mecanum Wheel (Drive Wheel) 213L 2nd axle (axle) 22R First Motor (Motor) 22L Second Motor (Motor) 3 Batteries 4 controllers 6 Storage Boxes 71 Base member 71b Rear base member (one of a pair of beam-like members) 71f Front base member (the other of a pair of beam-like members) 72R First arm member (arm member) 721R 1st connection part (connection part) 722R First oscillating end (oscillating end) 72L Second arm member (arm member) 721L 2nd connection part (connection part) 722L Second oscillating end (oscillating end) 75R First spring component (spring component, tension spring) 751R One end 752R other end 75L Second spring component (spring component, tension spring) 751L One end 752L Other end B1 Bellcrank Mechanism B2 Bellcrank Mechanism F Conveyor surface L1 Distance (distance between the axis of rotation and the axle) L2 Distance (distance between the axis of rotation and the connecting part) Ow1 First pivot axis (rotation axis) Ow2 Second pivot axis (rotation axis)

Claims

1. A transport assist device positioned between the front and rear wheels in the front-to-rear direction of a caster-equipped bed having multiple casters, including front and rear wheels, to assist in the manual movement of the bed. A base member fixed to the lower part of the bed, An arm member connected to the base member and swinging around a rotation axis extending in the left-right direction of the bed, A drive wheel having an axle supported by the aforementioned arm member and which swings integrally with the arm member, The system includes a spring member that biases the swing of the arm member so as to press the drive wheel against the conveying surface of the bed, The spring member is, One end connected to the aforementioned arm member, It has the other end which is positioned either in front of or behind the one end and connected to the base member, The base member is composed of a pair of front and rear beam-like members that span between the side frames of the bed. The arm member is connected to one of the pair of front and rear beam-like members. The other end of the spring member is connected to the other of the pair of front and rear beam-shaped members. A transport assistance device characterized by the following features.

2. In the transport assist device described in claim 1, Between the pair of front and rear beam-shaped members, The aforementioned drive wheel and, A motor connected to the aforementioned drive wheel, A housing box containing a controller for controlling the motor is provided. A transport assistance device characterized by the following features.

3. A transport assist device positioned between the front and rear wheels in the front-to-rear direction of a caster-equipped bed having multiple casters, including front and rear wheels, to assist in the manual movement of the bed. A base member fixed to the lower part of the bed, An arm member connected to the base member and swinging around a rotation axis extending in the left-right direction of the bed, A drive wheel having an axle supported by the aforementioned arm member and which swings integrally with the arm member, The system includes a spring member that biases the swing of the arm member so as to press the drive wheel against the conveying surface of the bed, The spring member is, One end connected to the aforementioned arm member, It has the other end which is positioned either in front of or behind the one end and connected to the base member, The base member is composed of a pair of front and rear beam-like members that span between the side frames of the bed. Between the pair of front and rear beam-shaped members, The aforementioned drive wheel and, A motor connected to the aforementioned drive wheel, A housing box containing a controller for controlling the motor is provided. A transport assistance device characterized by the following features.

4. In the transport assist device described in claim 2 or 3, The motor and the controller are equipped with a battery that supplies power to them. The battery is located outside the housing box. The battery is configured to be detachable from the bed. A transport assistance device characterized by the following features.

5. A transport assist device positioned between the front and rear wheels in the front-to-rear direction of a caster-equipped bed having multiple casters, including front and rear wheels, to assist in the manual movement of the bed. A base member fixed to the lower part of the bed, An arm member connected to the base member and swinging around a rotation axis extending in the left-right direction of the bed, A drive wheel having an axle supported by the aforementioned arm member and which swings integrally with the arm member, The system includes a spring member that biases the swing of the arm member so as to press the drive wheel against the conveying surface of the bed, The spring member is, One end connected to the aforementioned arm member, It has the other end which is positioned either in front of or behind the one end and connected to the base member, The spring member is composed of a tension spring that contracts to pull in the arm member. The arm member constitutes a bell crank mechanism with the spring member as the driving element and the axle as the driven element. The axle is positioned in front of or behind the rotation axis. The connection between the one end of the spring member and the arm member is positioned above the rotation axis. In the side view along the left-right direction, the distance between the rotation axis and the axle is longer than the distance between the rotation axis and the connecting portion. A transport assistance device characterized by the following features.

6. A transport assist device positioned between the front and rear wheels in the front-to-rear direction of a caster-equipped bed having multiple casters, including front and rear wheels, to assist in the manual movement of the bed. A base member fixed to the lower part of the bed, An arm member connected to the base member and swinging around a rotation axis extending in the left-right direction of the bed, A drive wheel having an axle supported by the aforementioned arm member and which swings integrally with the arm member, The system includes a spring member that biases the swing of the arm member so as to press the drive wheel against the conveying surface of the bed, The spring member is, One end connected to the aforementioned arm member, It has the other end which is positioned either in front of or behind the one end and connected to the base member, The spring member is composed of a tension spring that contracts to pull in the arm member. The arm member constitutes a bell crank mechanism with the spring member as the driving element and the axle as the driven element. The aforementioned arm member is A connecting portion connected to one end of the spring member, It has a pivoting end that supports the axle, The spring member is arranged to extend forward or backward in the front-rear direction from the other end, which is a fixed end, toward the one end, which is a free end, The arm member is positioned to extend from the connecting portion toward the swinging end in the opposite direction to the spring member in the front-rear direction. A transport assistance device characterized by the following features.

7. In the transport assist device described in claim 1, The arm member and the spring member are positioned so as not to overlap with the drive wheel when the transport assist device is viewed from above. A transport assistance device characterized by the following features.

8. In the transport assist device described in claim 1, 2, 3, 5, 6, or 7, The transport assist device is positioned in the center of the front-to-back area beneath the bed. A transport assistance device characterized by the following features.

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