Wheel dolly improved in operation ability

Abstract

To provide a novel wheel dolly with improved operability, which allows an operator to perform wheel holding work at a rear operator position, without moving from a main work position for the wheel dolly, when detaching a wheel of a large sized vehicle using the wheel dolly.SOLUTION: A wheel dolly C comprises: a movable base 1; a lifting cradle 2; a left and right pair of rack arms 25 for supporting a wheel; and a tire holder 3 applied to a side part of a wheel W on the rack arms 25. The tire holder 3 has: a holder rod 31 which is movably supported to each rack arm 25. The holder rod 31 has on its front side, a hold piece 32, and has on its rear side, a holder operation piece 33. The holder rod 31 is slidable in a cross direction along the rack arms 25, and is supported rotatably around an axis center of the holder rod 31.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wheel dolly that supports removed wheels when inspecting the wheel area during maintenance of automobiles such as large trucks, and in particular to a wheel dolly that not only reduces the burden on workers but also securely holds the supported wheels, providing new operability and safety. [Background technology]

[0002] In servicing vehicles, including trucks and general passenger cars, it is preferable that the parts of the vehicle that need to be serviced are located close to the worker or in a position that is easy to see, in order to reduce the burden on the worker and enable accurate work. For this reason, in the past, when servicing low-lying parts such as wheels and axles, the vehicle has been lifted up to make inspection and part replacement easier. In this case, for example, when removing wheels, etc., a wheel dolly is prepared to support them, reducing the burden on the worker.

[0003] In consideration of reducing the burden on workers and ensuring a safer working environment, the applicant has made many developments regarding wheel dollies, many of which have already been patented, as shown in the prior art documents listed below (see, for example, Patent Documents 1 to 5). One of the technical problems facing these prior art technologies is to enable a wide variety of uses, particularly while ensuring safety during operation. In other words, from the viewpoint of ensuring work safety, it is necessary to reliably prevent the wheels from falling or falling off when supporting the wheels on the wheel dolly. For this reason, many tire holders that maintain the upright position of the wheels placed on the wheel dolly have been developed, and they have been well received and accepted at vehicle inspection and maintenance service sites.

[0004] However, in the conventional method, in most tire holder setting operations, the worker must go around to the left and right sides of the wheel dolly from the general rear operation position of the wheel dolly to set up the tire holder, and there is still room for improvement from the viewpoint of work efficiency. (1) The wheel dolly is moved so that it faces the side of the vehicle. The handle or grip for moving it is located on the rear side of the wheel dolly, and the wheel dolly is moved by the worker holding the handle and pushing it forward from behind. In other words, the side where the handle or grip for moving it is located is called the rear position (rear side) of the wheel dolly. (2) Move the wheel dolly forward along the width of the vehicle and insert the rack arm of the wheel dolly under the wheel. (3) Raise the rack arm so that the wheel is supported by the rack arm. (4) Move the wheel dolly backward along the width of the vehicle and remove the wheels from the vehicle. Because of this type of work procedure, the worker's main operating position is the rear position of the wheel dolly (this is sometimes referred to as the rear hand side or rear hand position).

[0005] To safely perform such transfer work, the wheels transferred to the wheel dolly must be securely held on the rack arm. In particular, in the case of a single tire, it is difficult to keep the wheel standing upright without external support, so it is desirable to hold the wheel firmly on a tire guard erected on the rack arm. To achieve this, the wheel is usually held on the rack arm by leaning it against the tire guard erected on the rack arm. However, simply tilting the wheels on the rack arm raises the risk of the wheels falling off when the wheel dolly is moved, so a method of attaching the wheels to the tire guard using a safety belt or chain has been provided.

[0006] However, this work is troublesome, so in reality it is rarely carried out. In other words, it is ideal to do this kind of work before removing the wheels from the axles and hubs, but because there are fenders and wheel housings around the wheels, these get in the way, and it is very troublesome to do the work before removing the wheels. Therefore, in reality, the only way to do it is to remove the wheels from the axles and hubs, pull the wheel dolly backward (to the side of the vehicle), and then put the safety belt or chain on. However, because the tire itself is circular, even if the worker thinks he has wrapped the tire around, the tire may come off. For this reason, in reality, wrapping the tire around the tire is rarely performed. Therefore, there was a need for a method to safely and securely hold the wheels on the rack arm without using the hanging method, and in particular a method to enable the worker to hold the wheels while being located at the rear of the wheel dolly. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5825872 [Patent Document 2] Patent No. 6108712 [Patent Document 3] Patent No. 608854 [Patent Document 4] Patent No. 6109386 [Patent Document 5] Patent No. 7106618 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention was made taking into consideration the above-mentioned background, and its technical objective was to develop a new wheel dolly with improved operability that would enable a worker performing maintenance and inspection work to complete wheel holding work at a rear handy position, so to speak, without moving from the main working position of the wheel dolly. [Means for solving the problem]

[0009] First, the wheel dolly with improved operability described in claim 1 is A movable base; A lifting stand is supported on the base so as to be able to rise and fall freely, The lifting platform is provided with a pair of parallel rack arms for supporting the wheels, The rack arm is provided with a tire holder that is fitted to a side portion (sidewall portion) of a wheel supported in a support space formed by the pair of rack arms, The tire holder includes a holder rod movably supported on each rack arm, The holder rod is provided with a holding piece at a front portion and a holder operation piece at a rear hand side. The holder rod is characterized in that it is supported so as to be slidable in the front-rear direction along the rack arm and rotatable about the axis of the holder rod.

[0010] In addition, the wheel dolly with improved operability described in claim 2 has the following features in addition to those described in claim 1: The pair of rack arms are characterized in that they are provided with bearing rollers on the opposing inner sides for rollingly supporting the wheels.

[0011] The wheel dolly with improved operability described in claim 3 has, in addition to the requirements described in claim 1 or 2, The tire holder provided on each rack arm is configured to support wheels in a double tire state, and is characterized in that it comprises an outer wheel tire holder that acts on the outer wheel attached to the outer side in the vehicle width direction of the vehicle, and an inner wheel tire holder that acts on the inner wheel attached to the inner side in the vehicle width direction of the vehicle.

[0012] In addition, the wheel dolly with improved operability described in claim 4 has the following features in addition to those described in claim 3: the holder rod of the tire holder for the inner wheel has a total length extending from a rear hand position to a front end side of the rack arm, On the other hand, the holder rod of the tire holder for the outer wheel has a length dimension from the rear hand position toward the front that is shorter than that of the holder rod for the inner wheel, The holder rod for the inner wheel is nested within the holder rod for the outer wheel.

[0013] The wheel dolly with improved operability described in claim 5 has, in addition to the requirements described in claim 1 or 2, A steering post for moving the wheel dolly is provided upright on the proximal side of the rack arm.

[0014] In addition, the wheel dolly with improved operability described in claim 6 has the following features in addition to those described in claim 5: The steering post is characterized in that it has a support hole at its lower portion for supporting the holder rod so as to be rotatable or slidable.

[0015] The wheel dolly with improved operability described in claim 7 has the following features in addition to those described in claim 6: The steering post is characterized in that it is provided with a clamp bolt for fixing the holder rod.

[0016] In addition, the wheel dolly with improved operability described in claim 8 has the following features in addition to those described in claim 4: In a configuration in which a holder rod for an inner wheel is nested inside the holder rod for the outer wheel, The steering post is provided with a clamp bolt for fixing a holder rod for an outer wheel, The holder rod for the outer wheel is characterized in that a clamp bolt for fixing the holder rod for the inner wheel is provided on the holder rod for the outer wheel.

[0017] The wheel dolly with improved operability described in claim 9 has, in addition to the features described in claim 1 or 2, The holder operating piece for rotating or sliding the holder rod is lever-shaped and formed so as to protrude radially outward from the holder rod, and is characterized in that the holder operating piece and the hold piece are formed so as to protrude in the same direction when viewed from the rotation axis of the holder rod.

[0018] The wheel dolly with improved operability described in claim 10 has, in addition to the requirements described in claim 2, The rack arm is made of a rigid member having an L-shaped cross section, The pair of left and right rack arms are arranged so that the pocket portions, which are the inside of the L-shaped cross section, face inward toward each other, and are characterized in that a support roller is provided in this pocket portion and a holder rod is provided on the outside of the pocket portion.

[0019] The wheel dolly with improved operability described in claim 11 has the following features in addition to those described in claim 10: When the holding piece is raised and applied to the side of the wheel, This configuration is characterized in that after the hold piece is rotated so as to enter the support space, the hold piece is further abutted against the upper end of the L-shaped cross section of the rack arm, thereby setting and maintaining the upright position of the hold piece.

[0020] The wheel dolly with improved operability described in claim 12 has, in addition to the requirements described in claim 2, The bearing roller is characterized in that it includes a carry-up sleeve fitted thereon and adapted to be retractable from a bearing position toward the hand side.

[0021] The wheel dolly with improved operability described in claim 13 has, in addition to the features described in claim 1 or 2, The base is a single-post type that supports the central portions of a pair of left and right rack arms so that they can be raised and lowered. The lifting platform is characterized in that it is rotatably mounted on the base in a plan view.

[0022] The wheel dolly with improved operability described in claim 14 has, in addition to the features described in claim 1 or 2, The base is characterized by being of a forklift-like parallel post type in which a pair of left and right rack arms can be raised and lowered relative to post frames arranged upright on the left and right.

[0023] The wheel dolly with improved operability described in claim 15 has, in addition to the features described in claim 1 or 2, The base is mounted on a movable platform that moves in the fore-and-aft direction of the vehicle on rails laid on the stall floor, and is characterized in that the base is freely movable in the width direction of the vehicle on the movable platform. The above problems are solved by the configurations described in each claim. Effect of the Invention

[0024] First, according to the invention described in claim 1, when the hold piece acting on the tire is slid back and forth or rotated via the holder rod, the operation piece of the hold piece (holder operation piece) is attached so as to face the rear side of the wheel dolly (the side closest to the worker), so the worker can slide back and forth and rotate the hold piece without changing his / her standing position. Specifically, for example, if the worker rotates the holder operation piece located close to his / her hand in an outward direction, the hold piece integrated via the holder rod can also be rotated outward to an upright state. Also, if the hold piece is rotated and raised to the maximum extent, the hold piece can be brought into contact with the side part (sidewall part) of the tire via the holder rod, and the hold piece can be reliably applied to the tire.

[0025] According to the invention described in claim 2, since the wheel mounted on the rack arm is provided with a support roller for rolling, even a tire weighing about 100 kg can be easily and reliably rotated on the rack arm. Therefore, for example, when attaching a wheel to the axle, even if the bolt hole position on the wheel side is slightly misaligned with the bolt position on the axle side, the wheel can be rotated on the support roller to easily align them, allowing the work to be carried out smoothly.

[0026] According to the invention described in claim 3, the tire holder is provided for the inner wheel and the outer wheel, the inner wheel is provided at a position near the tip of the rack arm, and the outer wheel is provided at an intermediate portion of the rack arm. Therefore, for example, when removing the wheels of a double tire one by one, that is, first removing the outer wheel and then removing the inner wheel, each wheel can be easily removed by separately operating both tire holders, and the removed wheel can be safely and securely held on the rack arm. Also, when transferring only one outer wheel with a wheel to the rack arm, the outer wheel is likely to tilt forward, but by operating the tire holder for the outer wheel, the outer wheel can be transferred while maintaining its upright state (self-supporting state). Incidentally, the tire holder on the front side (for the inner wheel) is not only used when removing the inner wheel, but can also function as a stopper to prevent the tire from slipping or falling off the rack arm when removing a double tire with hub from an axle.

[0027] According to the invention as recited in claim 4, the tire holder is configured by combining a holder rod for an inner wheel and a holder rod for an outer wheel in a nested manner, so that the tire holder (holder rod) can be configured compactly.

[0028] According to the invention described in claim 5, since an upright steering post is provided on the proximal side of the rack arm, for example, a wheel placed on the rack arm can be supported by tilting it against the steering post, and the steering post can also function as a tire guard. Also, since the steering post is provided, when a wheel is placed on the rack arm, for example, the wheel can be supported by being clamped between the tire holder and the steering post in a pressure-fitted state.

[0029] According to the invention as recited in claim 6, since the steering post is provided with a support hole for the holder rod, the steering post can also function as a support member for the holder rod.

[0030] According to the invention described in claim 7, since the steering post is provided with a clamp bolt for fixing the holder rod, the lock structure for fixing the holder rod can be specifically constructed with a simple mechanism.

[0031] Furthermore, according to the invention described in claim 8, in a configuration in which a small diameter cylindrical holder rod for the inner wheel is nested within a large diameter cylindrical holder rod for the outer wheel, a clamp bolt for fixing the holder rod for the outer wheel is provided on the steering post, and a clamp bolt for fixing the holder rod for the inner wheel fitted therein is provided on the holder rod for the outer wheel, so that the holder rod for the outer wheel and the holder rod for the inner wheel can be fixed independently and firmly.

[0032] According to the invention described in claim 9, the attachment phase of the hold pieces provided on both ends of the holder rod and the holder operation piece, i.e., the attachment angle with respect to the holder rod, are set in the same direction, so that the worker can reliably recognize the holding or release of the tire even if the hold pieces are not visible. Specifically, when the holder operation piece provided on the hand side end of the holder rod is rotated and slid to place the hold piece provided on the other end of the holder rod against the rear side of the tire, even if the position (phase angle) of the hold piece is hidden by the wheel transferred onto the rack arm and cannot be seen, the phase of the hold piece is the same as that of the holder operation piece, so the phase angle of the hold piece can be recognized by the phase angle of the hand-held holder operation piece, and the tire holding and release operations can be reliably performed from the worker's standing position.

[0033] According to the invention described in claim 10, in addition to the specific configuration of the rack arm, the arrangement of the rack arm, the support roller, the tire holder (holder rod), etc. are specified.

[0034] According to the invention described in claim 11, when the holding piece is rotated as far as possible so as to enter the support space and placed in an upright position (abutting against the side of the wheel), the holding piece is brought into contact with the upper end of the L-shaped cross section of the rack arm to maintain this upright position. Therefore, the rack arm, which is originally used to hold the wheel, can also function as a rotation stopper for the holding piece. Since the upper end of the L-shaped cross section of the rack arm is at a uniform position in the front-rear direction, the angle at which the hold piece is rotated and erected to the maximum will result in the hold piece being in a substantially identical inclined position at any position in the front-rear direction, and the hold piece can be maintained in a substantially identical static position. In addition, when a wheel is placed on the rack arm, the hold piece is often not visible to the worker, but in the above configuration in which the hold piece is kept in an erect state by abutting against the rack arm (the upper end of the L-shaped cross section), the worker can recognize that the hold piece has been rotated and erected to the maximum by the sound of the hold piece abutting against the rack arm (in addition to the phase angle of the holder operation piece).

[0035] According to the invention described in claim 12, a carry-up sleeve is fitted onto the support roller on the hand side (rear side). Therefore, when removing only one outer wheel of a double tire system, for example, the outer wheel alone is supported by this carry-up sleeve, and the inner wheel can be separated from the support roller by a gap equal to the thickness of the carry-up sleeve, allowing only the outer wheel to be removed reliably.

[0036] According to the invention described in claim 13, the lifting platform is provided on a single-post type base so as to be freely rotatable horizontally. This allows the worker to perform tire installation / removal and horizontal rotation while remaining in a standing position, eliminating the need to stand or squat during the installation / removal work, thereby reducing the burden on the worker.

[0037] In addition, according to the invention described in claim 14, since the base is a forklift-like parapost type, the wheels it supports can be lowered close to the floor surface, and a wheel dolly can be obtained that allows the wheels to be removed and attached while the vehicle is slightly lifted up (with the tires slightly off the floor surface).

[0038] According to the invention described in claim 15, the wheel dolly is designed to move on rails laid on the stall floor, so that even if the wheels it is equipped with are heavy, it can be moved smoothly with a light force, and the parallelism of the facing angle of the wheel dolly to the wheels (axles) is ensured, making alignment easy. [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 is a perspective view showing a wheel dolly of the present invention (a wheel dolly with improved operability) and a perspective view showing an example of the use of this wheel dolly. [Diagram 2] FIG. 2 is a perspective view showing a wheel dolly (a), and a perspective view seen from a different direction (b). [Diagram 3] FIG. 2 is a plan view (a) and a side view (b) showing a wheel dolly. [Figure 4] This is a projection view (rear view) of the wheel dolly as seen from the rear side (the side closest to the operator). [Diagram 5] This is a projection view (front view) of a wheel dolly seen from the front side. [Figure 6] FIG. 1A is an enlarged projection (rear view) of the wheel dolly as seen from the rear side (the side closest to the operator), and FIG. 1B is an enlarged perspective view of the support roller and its surroundings. [Figure 7] 1A is a plan view showing the vicinity of the tire holder with the holding piece acting on the wheel facing downward, FIG. 1B is a side view showing the vicinity of the tire holder, and FIG. [Figure 8] 11 is a perspective view showing how the horizontal rotation of the lifting platform is locked and released; FIG. [Figure 9]1A and 1B are explanatory diagrams showing the tire installation status of three-axle and four-axle large trucks, and the number of wheel dollies required when applying the wheel dolly of the present invention to separate, detach and mount these tires. [Figure 10] FIG. 1 is a side view showing a wheel dolly (front wheel dolly) of a type that supports only one tire. [Figure 11] This is a perspective view showing a parapost type wheel dolly. [Figure 12] This is a plan view (a) and a side view (b) showing a wheel dolly that moves on rails within a stall. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] The embodiment of the present invention will be described below as a preferred example, and further includes various modifications based on this technical concept. EXAMPLES

[0041] Hereinafter, a wheel dolly C with improved operability according to the present invention (hereinafter simply referred to as wheel dolly C) will be specifically described based on the illustrated embodiment. First, we will give an overview of how the Wheel Dolly C is used. As shown in Figure 1, for example, a wheel dolly C is used when performing maintenance on the wheels of a vehicle V that has been brought into a vehicle maintenance workshop. It supports the wheels W that are removed and attached during maintenance, and also moves the removed wheels W so that they do not get in the way of work when performing maintenance on the axles, brakes, or hubs. The wheel W described in this specification generally refers to a combination of a hub and brake drum provided in the center, a wheel attached to the hub, and a rubber tire provided on the outer periphery of the wheel. However, names such as double tire, single tire, and rear tire are used as they are in everyday use.

[0042] Next, we will outline recent trends in the maintenance of wheels W. In the case of medium and large trucks, the rear wheels are almost all double tires, and these double tires can be removed and attached from the axle in a state where the outer wheel W1 and inner wheel W2 are fixed to the center hub with wheel bolts, depending on the repair and inspection maintenance requirements at the time, or the outer wheel W1 and inner wheel W2 are separated from the hub as a tire with wheels attached, with the hub and brake drum still attached to the axle, and removed and attached one wheel at a time. For large trucks in particular, it is legally required that the tire with wheels must be separated from the hub at the time of 12-month inspection maintenance (commonly called vehicle inspection maintenance) to inspect the contact surface between the inner wheel W2 and the hub, and the contact surface between the outer wheel W1 and the inner wheel W2. For this reason, there is a demand for wheel dollies C that can stably support the extremely heavy wheels W for large vehicles, each of which weighs approximately 100 kg per wheel (outer wheel W1 and inner wheel W2). When distinguishing the wheels W of a double tire by individual wheels, the wheel on the outer side in the vehicle width direction is called the outer wheel W1, and the wheel on the inner side in the vehicle width direction is called the inner wheel W2.

[0043] Hereinafter, the wheel dolly C will be described. As an example, as shown in Fig. 1 to Fig. 5, this is configured by providing a lifting platform 2 that can be raised and lowered on a base 1, and this lifting platform 2 is provided by a rotation operation member 4 so as to be rotatable in a plan view relative to the base 1, and is configured to have a fixed relationship with the base 1. The base 1 will now be described. The base 1 adopts a single-post type support form, for example, and includes a wheel support frame 11 extending radially downward, and a post frame 12 using a cylindrical external cylinder, for example, is provided at approximately the center of the wheel support frame 11. Specifically, the wheel support frame 11 and the post frame 12 are attached by bolting the base of the wheel support frame 11 to the base block 12a of the post frame 12, which is the external cylinder. The wheel support frame 11 also adopts a form in which the support position of the rolling wheels 13, for example, a swivel caster supported at the tip, is raised upward so that the post frame 12 can be supported as low as possible. As for the rolling wheels 13 supported by the wheel support frame 11, swivel casters are applied to all four wheels, for example, so that the base 1 is freely movable. It is also preferable that some or all of the rolling wheels 13 using the swivel casters are equipped with brakes. Of the four rolling wheels 13, only one may be a fixed caster, or both may be fixed casters.

[0044] The post frame 12, which utilizes a cylinder outer tube, is equipped with a foot pedal 14 for pumping hydraulic oil, and a release pedal 15 for opening the hydraulic circuit, located next to it. In order to facilitate such foot operation, a work tray 29, which will be described later, has been devised.

[0045] Furthermore, the mechanism of the foot pedal 14 and the release pedal 15 itself is a configuration that is usually applied to hydraulic cylinders, so further detailed explanation will be omitted. Meanwhile, a flange-shaped lock piece 16 is fixed near the upper end of the post frame 12 to which the external cylinder is applied, and this lock piece 16 has, as an example, lock recesses 16a at three locations in the front and left and right directions, spaced at 90° intervals. That is, in this embodiment, only the rear portion on the near side is configured without the lock recesses 16a. The front and left and right directions will be explained in detail later.

[0046] Next, we will explain the lifting stand 2 that is supported so as to be able to rise and fall freely on the base 1. The lifting stand 2 has a base plate 22 provided on the upper end of a lifting rod 21 supported by a post frame 12, and a table substrate 23 supported on this base plate 22 (see FIG. 8). As described above, the lifting rod 21 is essentially a sliding rod of a cylinder device, since the post frame 12 itself is an external cylinder. That is, a cylinder device is used as a member for supporting the lifting stand 2 so that it can be raised and lowered. When using such a cylinder device, the lifting rod 21 itself not only moves in the lifting direction, but is also configured to be rotatable in a plan view relative to the post frame 12, i.e., the external cylinder. The base plate 22 is, for example, a rectangular strength member fixed to the upper end of the lifting rod 21, and a peripheral frame plate 24 is provided to this to form a table base 23 that is shaped like a tray as a whole. Here, reference numeral 24a in the drawing indicates side peripheral frame plates erected on the left and right sides as seen by a worker M standing at the rear of the wheel dolly C. Reference numeral 24b in the drawing indicates a front peripheral frame plate erected on the rear side (forward side) as seen by the worker M. Reference numeral 24c in the drawing indicates a rear peripheral frame plate erected on the near side as seen by the worker M.

[0047] Furthermore, a pair of rack arms 25 are provided in a fork shape on the left and right sides by utilizing the peripheral frame plate 24. For the purpose of explaining this device, the front-rear direction, width direction, and left-right direction will be clarified here. In this device, since the lifting platform 2 rotates in a plan view with respect to the base 1, it is difficult to conceive of at least a common front-rear direction, so that it will be defined for each member. First, with regard to the base 1, the worker M stands facing the foot pedal 14 and release pedal 15, which are frequently operated, and the front-rear direction of the worker M in this standing position is defined as the front-rear direction, the opposite side of the foot pedal 14 and release pedal 15 is defined as the front, and the worker side is defined as the rear or near side. On the other hand, for the lifting stand 2, the longitudinal direction of the rack arm 25 is referred to as the front-rear direction, and the direction in which the pair of rack arms 25 are arranged opposite each other is referred to as the left-right direction or width direction (width direction of the lifting stand 2). Note that the side of the lifting stand 2 where a steering post 27, which will be described later, is provided is referred to as the rear or front side, and the opposite side is referred to as the front. The surface formed by the pair of rack arms 25 is the bearing surface S1 of the wheel W as shown in Fig. 4. However, considering that the wheel W is a circular wheel, the lower part of the wheel W is supported in a submerged state in the space below the bearing surface S1, and the space including this space where the wheel W is essentially mounted is referred to as the bearing space S2.

[0048] Moreover, the rack arms 25 are formed, for example, from so-called angle bars having an L-shaped cross section, with one of the blades 25a arranged horizontally and the other blade 25b arranged facing upward (see FIG. 6(b)). As a result, the left and right rack arms 25 made of angle bars are configured such that the narrower portions surrounded by the blades 25a and 25b, that is, the pocket portions 25c, are arranged facing inward and facing each other. Each rack arm 25 has a support roller 26 in an inner pocket 25c for directly supporting the wheels W, and as an example, two support rollers 26 are provided in a vertical row, one in front and one in back. As a result, a total of four support rollers 26, one pair in front and one pair in left and right, are configured to rotate independently, and each of the two wheels W transferred onto the rack arm 25 is supported rotatably. A carry-up sleeve 26s is provided on the support roller 26 that receives the outer wheel W1 on the near side, i.e., the rear side, so as to be slidable and rotatable in the front-rear direction, and the radial thickness of the carry-up sleeve 26s is set to, for example, about 10 mm. The function of the carry-up sleeve 26s will be described later.

[0049] Further, near the rear end of the rack arm 25 integral with the lifting platform 2, a steering post 27 is erected to move the wheel dolly C in an appropriate direction, such as for pushing and pulling the wheel dolly C. The steering post 27 is formed, for example, from a steel square pipe material, and is formed in a pair on the left and right sides at the rear (near side) of the lifting platform 2, and a steering grip 27a is provided behind the steering post 27 as a handle for the worker M to hold. The erected steering post 27, together with the holding piece 32 of the tire holder 3 set so as to be able to protrude into the support space S2, serves to hold the wheel W placed on the support roller 26 by sandwiching it from the front and rear directions (clamping support), and the steering post 27 itself can reliably prevent the tire from falling over toward the hand side, i.e., toward the worker M. The steering post 27 also serves to support the wheel W placed on the support roller 26 by tilting it toward the near side.

[0050] Furthermore, the lifting platform 2 is provided with a cylindrical drive shaft storage section 28 for storing the drive shaft D that may be removed when the wheels W are maintained. This drive shaft storage section 28 is welded and fixed near one of the side peripheral frame plates 24a so as to penetrate through the front peripheral frame plate 24b and the rear peripheral frame plate 24c described above, and is formed in a gentle slope that descends toward the front side. Incidentally, the cylindrical drive shaft storage section 28 is formed in such a gentle slope because This is because the drive shaft D is installed in an oil bath-shaped housing when it is installed in the vehicle. In other words, since it is inevitable that oil will adhere to the drive shaft D when it is removed from the vehicle V, the removed drive shaft D is stored in the drive shaft storage section 28, and the oil adhering to the drive shaft D is allowed to flow down to the front side and collected. For this reason, an oil container 28a is provided on the front side of the drive shaft storage section 28 to collect the oil that has flowed down and temporarily store it therein. This configuration makes it possible to prevent the oil adhering to the drive shaft D from dropping onto the floor of the maintenance workshop or the like. It is preferable that the oil container 28a be detachable from the lifting stand 2, for example, by using a magnet.

[0051] Furthermore, a work tray 29 is provided between the pair of steering posts 27 on the left and right, utilizing the lower portions of these posts. This work tray 29 is rectangular in plan view, and is provided with edge plate guides 29a formed to rise upward around its periphery, so that hand tools temporarily stored on the work tray 29 and parts such as removed bolts and nuts do not fall carelessly. The edge plate guides 29a on the front side facing the worker M are formed to be inclined so as to open outward, and the center part is formed in a notch shape (this is called an avoidance notch 29b), and the existence of this avoidance notch 29b prevents the worker M from hitting his knees against the work tray 29 when he operates the foot pedal 14 with his foot. In addition, a center handle 29c is provided in front of the avoidance notch 29b, and this center handle 29c is intended to allow the worker M to move the wheel dolly C straight forward and backward even with one hand.

[0052] Next, the tire holder 3 that holds the wheel W supported on the pair of left and right rack arms 25 by sandwiching it from the side of the tire will be described. That is, the tire holder 3 is a member that reliably holds the wheel W supported on the rack arms 25, more specifically the support rollers 26, in an upright state so that it does not fall over or drop off. Here, the "side" of the tire (wheel W) refers to the sidewall portion of the tire, and not the contact surface (tread portion). Note that in this specification, when the side of the tire or wheel W is mentioned, it refers to the sidewall portion as described above. 7, the tire holder 3 includes a holder rod 31 supported in a movable state with respect to each rack arm 25, and the holder rod 31 is provided with a hold piece 32 on the front side that acts to contact the side of the tire, and a holder operation piece 33 for sliding or rotating the hold piece 32 on the rear hand side. Specifically, the movable state of the holder rod 31 is a state in which the holder rod 31 is supported so as to be slidable in the front-rear direction along the rack arm 25 and rotatable about the axis of the holder rod 31 (this state is sometimes referred to as loose support). With this configuration, the holder operation piece 33 and the hold piece 32 are both formed in a lever-like shape that protrudes outward from the rotation axis (axial center) of the holder rod 31, and it is preferable that both are formed to protrude in the same direction (in the same phase when viewed in the axial direction) when viewed from the rotation axis of the holder rod 31.

[0053] Furthermore, when supporting double tires in particular, the tire holder 3 can be divided into one that acts on the outer wheel W1 and one that acts on the inner wheel W2, and these are distinguished as the tire holder for the outer wheel 3A and the tire holder for the inner wheel 3B. Here, in this specification, not only the tire holder 3 but also other members, when it is desired to distinguish between those that act on the outer wheel W1 and those that act on the inner wheel W2, the distinction is made by adding "A (for outer wheel)" or "B (for inner wheel)" to the end of the reference numeral. In this specification, for example, the holder rod for the outer wheel 3A is referred to as "for the outer wheel" in order to clearly distinguish it from the tire holder for the inner wheel 3B that acts on the inner wheel W2, but for example, the same wheel dolly C can also support a front single tire or a single wheel, and in this case, the holder rod for the outer wheel 3A acts on these tires other than the outer wheel W1. In other words, in this specification, even if it is referred to as "for the outer wheel (tire holder 3A)", this does not mean that it is limited to the outer wheel.

[0054] In this embodiment, the holder rod 31B of the tire holder 3B for the inner wheel has a total length extending from a rear hand position to the front end side of the rack arm 25. On the other hand, the holder rod 31A of the tire holder 3A for the outer wheel has a length extending from a rear hand position to the front, which is shorter than the holder rod 31B. These holder rods 31A and 31B are configured such that the holder rod 31B for the inner wheel is formed in a thin cylindrical shape and the holder rod 31A for the outer wheel is formed in a thick cylindrical shape, with the small diameter holder rod 31B nested inside the large diameter holder rod 31A. The members (parts) that movably support the two holder rods 31A and 31B thus nested together are provided at two locations: on the hand side and in front of it (approximately the middle position of the holder rod 31B). The support member on the hand side is the lower part of the steering post 27, and the support part is the support hole 27b that penetrates the steering post 27 in the front-rear direction (see Figs. 5(a) and 7(a)). On the other hand, the support member on the front side is a bearing-like bracket 25d provided on the outside of the blade 25b at a position slightly forward of the middle position of the rack arm 25 in the front-rear direction.

[0055] These support members (support parts) have different effective diameters for supporting the holder rod 31, and the support hole 27b on the hand side is formed with a diameter dimension (large diameter dimension) capable of supporting the holder rod 31A for the large-diameter outer wheel rotatably and slidably, while the effective support diameter of the bracket 25d is formed with a diameter dimension (small diameter dimension) capable of supporting the holder rod 31B for the small-diameter inner wheel rotatably and slidably. In other words, the effective support diameter of the bracket 25d is formed with a diameter dimension smaller than that of the support hole 27b in the steering post 27. With this configuration, when both holder rods 31A and 31B are assembled in a nested manner, the holder rod 31B for the small diameter inner wheel is supported at the front by the bracket 25d, and the holder rod 31A for the large diameter outer wheel is supported at the hand side by the support hole 27b of the steering post 27, so to speak, both holder rods 31A and 31B are supported in a state where they are interdependent in the front-rear direction. Of course, when the holder rod 31B for the small diameter inner wheel is nested inside the holder rod 31A for the large diameter outer wheel, the support hole 27b directly supports the holder rod 31A for the outer wheel, but also indirectly supports the holder rod 31B for the inner wheel.

[0056] The holder rods 31A and 31B thus configured can be rotated and moved (slid) forward and backward by operating the holder operation pieces 33A and 33B on the hand side. First, for the rotational operation, the hold piece 32 and the holder operation piece 33 are set to the same phase position when viewed from the axial direction of the holder rod 31, so in a natural standby state, both of them hang down due to their own weight. This standby state is common to both the left and right tire holders 3A and 3B, and is similar to a person's "attention" posture with both arms (hands) lowered downward. To bring the hold piece 32 from this standby state to an upright position, for example, as shown in Fig. 5, the holder operation piece 33 is rotated "from outside to inside," which is referred to as "outward rotation" in this specification. Incidentally, the expression "from outside to inside" is an expression based on the fact that it refers to a rotational movement of a person's arms from the "attention" posture described above to the outside of the body (a rotational movement that passes outside the body and faces upward).

[0057] When the holder operation piece 33 is rotated in this manner, the hold piece 32 integrated with the holder rod 31 also rotates outwardly and comes into contact with the upper end of the vertical wing plate 25b of the rack arm 25, so that the hold piece 32 is essentially inserted into the support space S2 of the wheel W. Of course, when the rotation of the hold piece 32 is stopped by abutment against the wing plate 25b, the holder operation piece 33 on the hand side cannot rotate any further because it is a same-phase rotation. In this manner, in this embodiment, the upper end of the rack arm 25 on which the wheel W is placed is also used as a rotation stopper for the hold piece 32. Incidentally, the state where the hold piece 32 abuts against the upper end of the vane 25b and stops rotating, that is, the operating position where the hold piece 32 enters the support space S2 and holds the wheel W, is an angle where the center of the hold piece 32 is inclined at an angle of about 18 degrees from the vertical line, as shown in Fig. 5(b) above as an example. Also, in this embodiment, clamp bolts 35A and 35B, which will be described later, are provided to lock the holder rod 31 against sliding and rotating, but the applicant has confirmed that when the hold piece 32 is in the inclined position as described above, the hold piece 32 can be kept stopped from rotating without locking it with the clamp bolts 35A and 35B. The length from the rotation axis of each of the holding pieces 32A and 32B to the tip thereof is set to a length that allows both pieces to securely hold the tire, but does not contact (scratch) the disk wheel or rim.

[0058] In addition, the front-rear position of the hold piece 32 must be appropriately set according to the tire width dimension of the wheel W to be serviced, and a certain length of the movement stroke in the front-rear direction is ensured for this purpose. That is, in the case of the outer wheel hold piece 32A, its front end position is the position where the front end of the holder rod 31A, which is integral with the hold piece 32A, abuts against the stopper ST1 provided near the base of the bracket 25d, while the rear end position is the position where the rear end of the holder rod 31A abuts against the stopper ST2 fixed near the rear end of the holder rod 31B for the inner wheel, and then the holder rod 31A and the holder rod 31B slide backward in conjunction with each other, and the base of the inner wheel hold piece 32B abuts against the front surface of the bracket 25d.

[0059] As for the inner wheel hold piece 32B, its front end position is a position where the stopper ST2 fixed near the rear end of the holder rod 31B, which is integral with the hold piece 32B, abuts against the rear end of the holder rod 31A for the outer wheel, and then the holder rod 31B and the holder rod 31A slide forward in conjunction with each other, and the front end of the holder rod 31A abuts against the stopper ST1. At this time, the length of the holder rod 31B is determined so that the hold piece 32B is located within the front end of the rack arm 25 (without protruding beyond the front end of the rack arm 25) and abuts against the vane 25b of the rack arm 25 when the hold piece 32B is rotated and erected. On the other hand, the rear end position of the inner wheel hold piece 32B becomes a position where the holder rod 31B integral therewith slides rearward and the base portion of the hold piece 32B abuts against the front surface of the bracket 25d.

[0060] Therefore, the movement stroke of the hold piece 32A and the hold piece 32B in the front-rear direction is within a range regulated by the stopper functions of the stopper ST1, the stopper ST2, and the front surface of the bracket 25d. Specifically, the movable range of the hold piece 32B for the inner wheel is 655.7 mm to 485.7 mm from the front end face of the steering post 27, as shown in Fig. 7(b), for example, and the stroke is 170 mm. On the other hand, the movable range of the outer wheel hold piece 32A is, for example, 320 mm to 150 mm from the front end face of the steering post 27, and the stroke is also 170 mm. Incidentally, since the tire width of a large truck is about 280 mm to 304 mm, the maximum tire clamping width per wheel of the hold piece 32 is set to about 320 mm, for example.

[0061] Furthermore, in order to reliably maintain the wheel W holding state in the tire holders 3A, 3B for the inner and outer wheels, each of the holder rods 31A, 31B is provided with a locking mechanism. First, to fix the holder rod 31A for the outer wheel, the clamp bolt 35A screwed into the outer surface of the steering post 27 is tightened toward the center of the support hole 27b of the steering post 27 to push in and fix the holder rod 31A from the side, with respect to the holder rod 31A penetrating the support hole 27b of the steering post 27. In other words, by tightening the clamp bolt 35A, the holder rod 31A is locked so that it cannot rotate or slide. On the other hand, the lock mechanism for fixing the holder rod 31B for the inner wheel is such that the clamp bolt 35B is screwed into the holder rod 31A for the outer wheel, and the holder rod 31B for the inner wheel, which is assembled inside the holder rod 31A in the form of an inner sleeve, is tightened and fixed. In this configuration, when fixing the holder rod 31B for the inner wheel so that it does not move, the holder rod 31A for the outer wheel is first fixed (locked), that is, the clamp bolt 35A is tightened, and then the clamp bolt 35B is tightened to fix (lock) the holder rod 31B for the inner wheel. Incidentally, the clamp bolt 35B is set so as to be almost straight (horizontal) when the tire holder 3B (hold piece 32B) is in an upright state (in contact with the vane 25b acting as a stopper).

[0062] Next, the rotation operation member 4 for rotating the lifting platform 2 in a plan view and for positioning it relative to the base 1, i.e., for setting it in a non-rotating state, will be described. As an example, as shown in FIG. 8, this member has a configuration in which one end of a square pipe-shaped operation rod 42 is rotatably connected to a pivot shaft 41 in a pivot bracket 40 provided on the underside of the lifting platform 2. The operation rod 42, which is the rotation operation member 4, hangs down freely from the pivot shaft 41, and in this state, the lower part of the operation rod 42, i.e., the part that abuts against the lock piece 16, appears to be engaged so as to fit into the lock recess 16a, setting the lifting platform 2 in a non-rotating state. In this configuration, since the operation rod 42 has a sufficiently long rod shape, even if the lifting platform 2 is near the top dead center, a part of the operation rod 42 (in this case, the free end side) always abuts and engages with the position of the lock piece 16 that is relatively spaced apart, and the non-rotating state can be maintained.

[0063] In this embodiment, an auxiliary operating rod 42A is provided at the hand side end of the pivot shaft 41 at a position protruding from the lifting platform 2. This auxiliary operating rod 42A is provided in a slightly upward-pointing state when the operating rod 42 is in the locked state. When the lifting platform 2 is rotated relative to the base 1, for example, the auxiliary operating lever 42A is rotated clockwise (clockwise as seen by the worker M) to rotate the operating rod 42 in the hanging state so as to lift it upward. This disengages the operating rod 42 from the lock piece 16, and by turning the operating rod 42 in this disengaged state, the lifting platform 2 can be rotated appropriately. Furthermore, the operating rod 42 that has been raised from a hanging state to an approximately horizontal state, i.e., the operating rod 42 that has disengaged from the locking piece 16, can be attracted to and held by the magnet 43 provided on the lower part of the table base 23, thereby maintaining the operating rod 42 in a horizontal state and allowing the lifting stand 2 to rotate smoothly and reliably.

[0064] In this way, after the lifting platform 2 has been rotated an appropriate angle, i.e., after the lifting platform 2 has been rotated 90 degrees to the left or right in a plan view, the lifting platform 2 is again fixed. This operation is the reverse of the above, and by rotating the auxiliary operating lever 42A in the opposite direction (counterclockwise), the attraction and holding by the magnet 43 is released, and the operating rod 42 is changed from a substantially horizontal state to a hanging state, and finally the lower part of the operating rod 42 is fitted into the lock recess 16a, completing the locking.

[0065] In addition to the above-mentioned configuration, in this embodiment, as accessories for improving workability, an impact wrench holder IH is provided on the steering post 27 on the right side as viewed from the operator M, and a side tray ST is provided on the opposing steering post 27 on the left side.

[0066] The wheel dolly C of the present invention has the basic structure as described above, and below we will explain how to use this wheel dolly C to remove a wheel W from a vehicle V and how to attach the removed wheel W to the vehicle V, particularly an example of the ISO method. In the following explanation, we will mainly explain how to remove each wheel of the dual rear tires of a large truck from the hub. Of course, in this type of work, the outer wheel W1 of the dual tire is removed first, and then the inner wheel W2 is removed. Incidentally, the work of removing the wheels W may involve removing the wheels W with the hubs and drums attached from the vehicle V (vehicle body), or may involve removing only the wheels W with the wheels attached while leaving the hubs and drums attached to the vehicle, and the following explanation will be on the latter. Also, during vehicle inspection and maintenance, especially in the case of large trucks, it is legally required to remove each of the front and rear dual tires from the hubs for maintenance and inspection. In addition, when removing the twin tires one wheel at a time, the outer wheel W1 is first placed on the near side of the rack arm 25, and then the inner wheel W2 is placed on the front side of the vacant rack arm 25. In addition, since the axle of the vehicle V is lifted up in a horizontal state, as shown in FIG. 1, the side of the wheel W to be removed is inevitably nearly vertical. The wheel dolly C is used to remove the wheel W from the axle by removing the hub nut and hub bearing located in the center of the wheel W, and to remove the wheel with tire from the hub by removing multiple wheel nuts while leaving the hub on the axle. Therefore, the wheel dolly C makes it easier to remove and install the wheel W when the wheel dolly C holds the wheel W in a nearly vertical upright state on the rack arm 25, rather than, for example, when the wheel W is tilted toward the steering post 27. Therefore, in the following explanation, the wheel W will basically be described as being held in an upright state on the rack arm 25.

[0067] (1) Condition of the vehicle As shown in Fig. 1, the vehicle V from which the wheels W are to be removed is lifted up to an appropriate height in advance by a lift L. This height is set so that a worker M can perform the work in a standing position.

[0068] (2) Starting state of the wheel dolly On the other hand, the wheel dolly C is usually set at a low height so that the lifting platform 2 (rack arm 25) can support the wheels W, taking into consideration the lifted-up state of the vehicle V. This is to enable the wheel dolly C to be smoothly inserted directly under the wheels W. At this time, in the support roller 26 that directly supports the wheels W on the rack arm 25, the carry-up sleeve 26s rotatably fitted on the support roller 26A for the outer wheel is moved forward from the retreat position at the hand side end (a position rearward of the front surface of the steering post 27 when viewed from the side) to the support position of the outer wheel W1. This is to prepare for the reception of the inner wheel W2, which is transferred onto the rack arm 25 following the outer wheel W1 that has already been placed. Details will be described later.

[0069] (3) Removing the outer wheel (i) Setting of tire holder In addition, in order to make it easy to insert the wheel dolly C smoothly under the wheel W and place the wheel W on the rack arm 25, the tire holder 3 is kept in a retracted position where the hold piece 32 does not protrude into the support space S2, i.e., hanging downward from the holder rod 31 (standby state).

[0070] (ii) Moving the wheels of the wheel dolly downward (insertion movement) After that, the worker M grasps the steering grip 27a of the steering post 27 and moves the wheel dolly C so that the center of the left and right rack arms 25 is almost directly below the center of the wheel W. Then, the wheel dolly C is pushed in the axial direction until the left and right steering posts 27 approach or lightly abut the front side of the tire, and at that position, the worker M operates the foot pedal 14 by raising his foot. This causes the lifting platform 2 (rack arm 25) to rise, and when the carry-up sleeves 26s fitted on the left and right support rollers 26A approach or lightly abut the lower part of the outer wheel W1, the foot operation is stopped. By such an operation, the outer wheel W1 is located directly above the support roller 26A on the hand side, and the inner wheel W2 is located directly above the support roller 26B on the tip side.

[0071] (iii) Standing up of the holding piece for the outer wheel (rotation in an outward direction) In this state, first, the tire holder 3A for the outer wheel is operated to rotate its holding piece 32A so as to stand up and place it against the front side (rear side) of the outer wheel W1 (into the support space S2). That is, this operation can be performed without moving from the hand side position where the worker M operated the steering grip 27a, and the holder operating piece 33A for the outer wheel at hand is operated to shift the holder rod 31A back and forth, and the position of the holding piece 32A is adjusted to a position where the outer wheel W1 can be held. In other words, the above operation causes the holding piece 32A to enter the support space S2 between the outer wheel W1 and the inner wheel W2, and the outer wheel W1 is sandwiched between the steering post 27 and the holding piece 32A. As described above, the rotated holding piece 32A abuts against the upper end of the blade 25b of the rack arm 25 and maintains the upright state (see FIG. 5(b)). After the holding piece 32A is set in the holding position for the outer wheel W1 in this manner, the clamp bolts 35A that are screwed into the left and right steering posts 27 so as to be capable of projecting and retracting are tightened to prevent the holder rod 31A from sliding and rotating and to fix the position of the holding piece 32A. Of course, such tire holders 3A are set symmetrically in pairs on the left and right rack arms 25. As a result, the outer wheel W1 is supported by the carry-up sleeve 26s and is securely accommodated in the support space S2 in an upright state.

[0072] (iv) Supporting the wheels with rack arms (removing wheel nuts) Thereafter, the worker M first removes the wheel nuts fastening the outer wheel W1 to the hub, and places the removed wheel nuts on the work tray 29. Then, the worker M operates the foot pedal 14 in a tilting motion to slightly raise the lifting platform 2 (rack arm 25), thereby removing the weight of the outer wheel W1 applied to the wheel bolt. Here, the outer wheel W1 is supported by the support roller 26A on the hand side, and since the support roller 26A is provided with a carry-up sleeve 26s, the outer wheel W1 is supported at a position substantially higher than the roller outer circumference by the thickness of the sleeve. In other words, a gap (carry-up gap G) is maintained between the support roller 26B on the front side of the rack arm and the inner wheel W2 by the thickness of the carry-up sleeve 26s, and the inner wheel W2 is maintained in a non-contact state with the support roller 26B.

[0073] (v) Pulling out and moving the wheel dolly Thereafter, the worker M moves the entire wheel dolly C so as to pull it out from under the vehicle V to the side of the vehicle. This allows the outer wheel W1 together with the wheel to be removed from the vehicle V while being placed on the rack arm 25 (carry-up sleeve 26s). At this time, if the outer wheel W1 is firmly fixed to the inner wheel W2, the outer wheel W1 may not easily separate from the inner wheel W2 even if the worker M simply pulls the wheel dolly C. However, even in such a case, the hold piece 32A protruding into the support space S2 abuts in an engaged state against the back surface of the tire width of the outer wheel W1 (the surface at the rear in the vehicle width direction), so that by repeating the pulling-out operation of the wheel dolly C several times, the outer wheel W1 can be pulled away from the inner wheel W2 and removed from the vehicle V. Furthermore, as described above, the inner wheel W2 is not in contact with the support roller 26B, so that the removal operation of only the outer wheel W1 can be performed reliably by the above-mentioned pulling out operation.

[0074] (vi) Standing of the holding piece for the inner wheel (rotation in an outward direction) After the removal of the outer wheel W1 is completed, the wheel dolly C is again adjusted to a position to receive the inner wheel W2, and the holding piece 32B for the inner wheel is set. This operation is substantially the same as that for the outer wheel W1, and the holding piece 32B is applied to the side of the inner wheel W2 at the rear. Specifically, the holder operation piece 33B is first moved in the front-rear direction to set the holding piece 32B to an appropriate front-rear position, and then the holder operation piece 33B is operated again to rotate the holder rod 31B in an outward direction, and the holding piece 32B is placed in an upright position so as to be placed in an upright position on the side of the inner wheel W2 at the rear. When the holding piece 32B is in an upright position, the inner wheel W2 is sandwiched between the holding piece 32A, which is in an upright position on the front side (rear side), and the holding piece 32B, which is in an upright position on the rear side (front side). After performing the above operations, the holding piece 32B for the inner wheel is fixed by tightening the clamp bolt 35B provided on the holder rod 31A, and depending on the holder rod 31A already set in a fixed state, the holding piece 32B is fixed in a holding position for the inner wheel W2 (so that it cannot slide or rotate).

[0075] (4) Removing the inner wheel With the tire holder 3B set as described above, looking at the relationship between the rack arm 25, more specifically the bearing roller 26B and the inner wheel W2, as described above, the carry-up sleeve 26s is fitted onto the bearing roller 26A for the outer wheel W1, so a slight carry-up gap G is generated between the bearing surface of the bearing roller 26B (see Figs. 5 and 6), and the inner wheel W2 is supported above the bearing roller 26B by this gap. In other words, the inner wheel W2 is located directly above the bearing roller 26B, maintaining the carry-up gap G between the bearing roller 26B and the inner wheel W2. Therefore, if the worker M operates the foot pedal 14 to slightly raise the lifting platform 2, the bearing roller 26B can be brought into contact with the inner wheel W2 from below and supported. Thereafter, in the same manner as the outer wheel W1, the wheel dolly C is moved forward (outside in the vehicle width direction) so as to be pulled away from the vehicle V, and the inner wheel W2 is removed from the hub. Currently, for large trucks, there are JIS type and ISO type wheel mounting structures for dual tires, and in the case of the JIS type, when removing the inner wheel W2, it is necessary to remove the inner nut (flange nut). In addition, since the outer wheel W1 and the inner wheel W2 can be separated and removed, it becomes easier to inspect and maintain the joint surfaces of the outer wheel W1 and the inner wheel W2 as required by law during vehicle inspection and maintenance work.

[0076] (5) Inspection After removing the outer wheel W1 and the inner wheel W2 in the above manner, the worker M inspects the wheel bolts, the contact surface between the hub and the wheel, the joint surfaces of the outer wheel W1 and the inner wheel W2, etc. At this time, especially when inspecting the vehicle side, the wheel dolly C carrying the outer wheel W1 and inner wheel W2 is moved slightly to the side away from the vehicle V, ensuring space between the vehicle V and the worker M for him to enter, making it easier to perform maintenance and inspection work there. In this way, the worker M performs maintenance and inspection of the entire wheel W, the wheel, the tire, the wheel nuts and wheel bolts for tightening the wheels, etc. Also, after inspecting the joint surface between the outer wheel W1 and the inner wheel W2, if there is rust or the like, it is removed as much as possible.

[0077] (6) Brake inspection Next, the drive shaft D is removed with the double tires still attached, and the brake drum is also removed as a unit, allowing the condition of the brakes, including the brake shoes, to be inspected. Specifically, the inner wheel W2 and the outer wheel W1 are attached to the vehicle V in the reverse order to the removal of the wheel W, and then the drive shaft D is pulled out and the axle housing AH is released from the assembly of the dual tires. The removed drive shaft D is inserted into the drive shaft storage section 28 and stored therein. At this time, the double tire-shaped wheel W is again supported by the rack arm 25 of the wheel dolly C, and when the wheel dolly C is pulled out to the side of the vehicle V, the wheel W is removed from the vehicle body together with the hub and brake drum. When removing the wheel W in the double tire state, the carry-up sleeve 26s prepared for the outer wheel W1 is moved to the retracted position at the end at hand, that is, to a position rearward of the front face of the steering post 27 when viewed from the side, so as not to contribute to the support.

[0078] In addition, there is some resistance when the wheel dolly C supporting the wheels W in double tire state is pulled out to the side of the vehicle V, but since the hold piece 32B for the inner wheel in the tire holder 3 is raised so that it is against the rear side of the inner wheel W2, by pulling the wheel dolly C out with a certain degree of impact, the hold piece 32B will come into contact with the inner wheel W2 (the rear side), and the wheel dolly C carrying the double tire-shaped wheels W can be pulled out. When removing the double-tire wheel W, it is sufficient to rotate the inner wheel hold piece 32B to the upright position as described above, but it is also possible to rotate the outer wheel hold piece 32A to the upright position. When only the inner wheel hold piece 32B is rotated to the upright position, the double-tire wheel W is sandwiched between the steering post 27 and the hold piece 32B from the front and rear directions, and when both the inner wheel hold piece 32B and the outer wheel hold piece 32A are rotated to the upright position, the outer wheel W1 is sandwiched between the steering post 27 and the hold piece 32A from the front and rear directions, and the inner wheel W2 is sandwiched between the two hold pieces 32A and 32B from the front and rear directions.

[0079] When inspecting the brakes, it is not impossible to remove the wheels W that were removed during the inspection of the wheels W, and then remove the brake drum to inspect the brakes. However, in reality, the brake drum weighs several tens of kilograms, so a separate support dolly or the like would be required to remove it alone, which is not practical. For this reason, the double tire-shaped wheel W is first attached to a hub assembly with an integrated brake drum, and then this is removed from the vehicle body and maintenance is carried out using the conventional procedures, such as replacing the axle housing AH, hub grease, brake drum, brake shoes, etc. Furthermore, work such as changing the hub grease on the hub of a wheel W that has been removed from the vehicle body and mounted on a wheel dolly C is done by facing the hub from the axle direction. Even if the wheel dolly C is moved straight back to the side of the vehicle V (in the width direction of the vehicle V), in a repair shop with a narrow work stall width, there is not enough working space for a worker M to stand between the vehicle V and the wheel W and work facing the hub of the wheel W. Therefore, it is desirable to horizontally rotate the lifting platform 2 (rack arm 25) 90 degrees to the left or right relative to the base 1 and lock it.In this way, the axle line of the wheels W mounted on the wheel dolly C will face the longitudinal direction of the work stall, ensuring sufficient work space even if the worker M faces the hub of the wheel W. After the above-mentioned maintenance and inspection work is completed, the lifting platform 2 (rack arm 25) is returned 90° to the horizontal direction, and the double tire-shaped wheels W are attached to the vehicle V.

[0080] (7) Other removal methods (installation methods) The manner in which the dual tires are removed (attached) with the hubs has been described above, and other removal methods will be outlined below. For example, in the case of medium-sized trucks, the twin rear tires may be removed while still connected. This is because, as mentioned above, only large trucks are legally required to have their wheels removed from the hubs for inspection during vehicle inspection. Also, for example, in the case of a small truck, the double rear tires and the single front tire may be placed on the same wheel dolly C and removed, resulting in a total of three wheels W being placed on the rack arm 25. In this case, the single front tire can be held between the steering post 27 and the holding piece 32A, and then the double rear tires with their hubs attached can be placed on the rack arm 25. Since the double rear tires can stand on their own on the rack arm 25, it is not necessary to raise the holding piece 32B of the tire holder 3, i.e., to place them in the operating position. Of course, there is no problem with holding the double tires with the holding piece 32B in the operating position. Furthermore, as another mode of removal, in the case of a small or medium-sized truck or a passenger car, for example, all the wheels on one side can be placed on a wheel dolly C (rack arm 25).

[0081] Since such various mounting configurations are possible, the present invention makes it possible to greatly reduce the number of wheel dollies C required. In other words, with the exception of tractors that tow trailers, the majority of large trucks are so-called three-axle vehicles (six wheels with hub drums) and four-axle vehicles (eight wheels with hub drums), as shown in Fig. 9, for example, with four-axle vehicles accounting for more than 30% of the market. A typical three-axle vehicle, as shown in Figure 9(a), has one front axle with single tires (two on each side) and two rear axles with double tires (eight on each side), for a total of ten single wheeled tires (however, there are some three-axle vehicles with single tires on the two front axles and double tires on the single rear axle). For this reason, if one were to safely separate, install and load each of the single wheeled tires (wheels W) using a conventional wheel dolly C', a total of ten wheel dollies C' would be required. However, for a typical three-axle vehicle, if the Wheel Dolly C of the present invention is used, a total of six units will suffice. This reduction effect will be explained in detail below. First, wheel dollies C are used by placing them on the left and right sides of the vehicle V (axle) during maintenance and inspection work, and the left and right sides are never mixed. This is because mixing the left and right sides makes the work less efficient. For example, even if one wheel dolly C is used to remove and install one wheel (wheel W) for the single tire on the front axle, the eight single tires (wheels W) on the left and right that are separated from the double tires on the rear axle can be removed and installed using four wheel dollies C, so a total of six wheel dollies C will be sufficient.

[0082] As shown in FIG. 9(b), the four-axle vehicle has single tires on the two front axles and double tires on the two rear axles, so that a total of 12 single tires with wheels are installed. The eight single tires on the two rear axles can be handled in the same manner as the two rear axles of the three-axle vehicle described above. As for the four single tires on the two front axles (two on each side), although one wheel dolly C needs to be moved between the two front axles, two single tires on one side of the vehicle can be separated, detached, and mounted by one wheel dolly C (two on the left and right in total) (even if they have hub drums). Therefore, in the case of a four-axle vehicle, six wheel dollies C are sufficient in the present invention. In this regard, if a total of 12 single tires with wheels are to be safely separated, detached, and mounted on one wheel dolly C', a total of 12 wheel dollies C' would be required, but the present invention can significantly reduce the number of wheel dollies C required. Therefore, a maintenance workshop can carry out efficient vehicle inspection and maintenance work by equipping one stall with six wheel dollies C of the present invention, regardless of the type (number of axles) of large trucks that are brought into the workshop. Therefore, for automobile maintenance businesses, the number of wheel dollies C used in the vehicle inspection and maintenance stall can be significantly reduced while maintaining high work efficiency, resulting in more space for work, allowing maintenance and inspection work to be carried out reliably, and reducing equipment costs. The wheel dolly C described above has various advantages as mentioned above, but the most important feature and advantage to be emphasized is that, with the exception of maintenance inspections such as brake inspections and inspections around the hubs, when it comes to removing and installing the wheels W, the worker M can perform all operations safely and reliably from the rear of the wheel dolly C.

[0083] [Front wheel dolly] The above-described embodiment is capable of supporting a wheel W in a double tire state, and the rack arm 25 has a structure long enough to make this possible. However, as shown in FIG. 10, for example, a wheel dolly C1 capable of supporting only one wheel may be used exclusively for maintenance of a single-tire type front wheel. In this case, the rack arm 25 and the support roller 26 are naturally short in length, and are formed, for example, only with the support roller 26B on the front side in the basic embodiment. The wheel dolly C1, in which the rack arm 25 (support roller 26) is formed with a short length, can be easily handled, especially in a narrow stall with limited working space. The tire holder 3 is formed as a single unit on each of the left and right sides (one side). Specifically, for example, the holder rod 31 in the basic embodiment is formed as a single unit only with the holder rod 31B (for the inner wheel) provided on the front side, and the hold piece 32 is also formed as a single unit only with the hold piece 32B (for the inner wheel) provided on the front side. Of course, in the wheel dolly C1 for supporting only one wheel, the holder rod 31 does not have a nesting structure. Therefore, the clamp bolt 35 (35B) directly presses against the outer surface of the holder rod 31B, fixing the sliding and rotation. In addition, the wheel dolly C1 does not include the carry-up sleeve 26s or the drive shaft housing portion 28.

[0084] [Parapost type wheel dolly] Furthermore, in the embodiment already described, the rack arm 25 is shifted up and down by a single lifting rod 21, but it is also possible to adopt a so-called forklift-like parapost type lifting mechanism (wheel dolly C2), as shown in, for example, FIG. 11. That is, rack arm 25 is supported on post frame 112, which is one of the components of base 101, so as to be able to rise and fall freely, and this rack arm 25 is provided with various members of the same mechanism as the tire holder 3 described above. In this case, the mechanism for raising and lowering rack arm 25 can have various configurations, but this mechanism is not shown in the configuration example in Fig. 11 above. In addition, with this parapost type wheel dolly C2, the wheels W that it supports can be lowered close to the floor surface, so that the wheels W can be removed and installed with the vehicle V slightly lifted up (with the tires slightly off the floor surface). Of course, even this parapost type wheel dolly C2 can be configured for single tires, double tires, or any other purpose.

[0085] [Rail-type wheel dolly] Furthermore, in the basic embodiment described above, the wheel dolly C is structured so that the worker M can freely move it around the maintenance workshop using the rolling wheels 13 attached to the base 1. However, the movement of the wheel dolly C is not necessarily limited to the rolling wheels 13, and a rail system may also be adopted. That is, as an example, a rail-type wheel dolly C3, as shown in Figure 12, has a vertical rail R1 laid on the floor of a maintenance workshop in the fore-and-aft direction parallel to the side of the vehicle to be maintained, and a horizontal rail R2 that runs back and forth along the vertical rail R1 as a track. The horizontal rail R2 is a rail for allowing the horizontal carriage 18 to travel in a direction perpendicular to the vertical rail R1 (towards and away from the vehicle), and corresponds to the moving platform described in the claims. The traverse cart 18 is provided with exactly the same functions as the wheel dolly C, such as the post frame 12 and rack arm 25, and constitutes a wheel dolly C3. The cross-sectional shape of the horizontal rail R2 is, for example, a C-channel material, which is a general steel material, and the wheels (4 pieces) of the horizontal trolley 18 roll within the groove, which completely prevents the wheel dolly C3 from coming off or tipping over, while also allowing the overall height to be low. In addition, in the configuration example shown in FIG. 12, the vertical rails R1 are provided at approximately the same height as the floor surface of the maintenance workshop, so that there are almost no unevennesses on the floor surface. This allows the worker M to concentrate on the installation and removal of the wheels W and maintenance work without having to worry about the vertical rails R1. [Industrial Applicability]

[0086] The wheel dolly of the present invention can be used not only for vehicle maintenance, but also for general maintenance and inspection work of factory equipment and transportation support work. [Explanation of symbols]

[0087] AH ASKUL HOUSING C Wheel Dolly C1 Wheel dolly (for single wheel bearing) C2 Wheel Dolly (Parapost Type) C3 Wheel Dolly (Rail Type) D. Drive shaft G Carry-up gap L Lift M worker R1 Vertical rail R2 Horizontal rail S1 Supporting surface S2 Bearing space ST1 Stopper ST2 Stopper V Vehicles W wheels W1 Outer wheel (Double tire outer wheel) W2 Inner wheel (inner wheel of double tire) IH Impact Wrench Holder ST Side Tray 1 Base 2 Lifting stand 3 Tire holder 4 Rotation operation member 11 Wheel support frame 12 Post frame (cylinder outer tube) 12a Base Block 13 Rolling Wheel 14 Foot Pedal 15 Release pedal 16 Lock piece 16a Lock recess 18 Traverse Cart 21 Lifting rod 22 Base plate 23 Table Board 24 Frame plate 24a Side frame plate 24b Front perimeter plate 24c Rear surround 25 Rack Arm 25a Wing plate (horizontal) 25b Wing plate (vertical) 25c Pocket 25d bracket 26 Support roller 26A Bearing roller (for outer wheel) 26B Support roller (for inner wheel) 26s Carry Up Sleeve 27 Steering Post 27a Steering Grip 27b Support hole 28 Drive shaft housing 28a Oil container 29 Work Tray 29a Edge plate guide 29b Avoidance notch 29c center handle 3A Tire holder (for outer wheels) 3B Tire holder (for inner wheels) 31 Holder rod 31A Holder rod (for outer wheel) 31B Holder rod (for inner wheel) 32 Hold Piece 32A Hold piece (for outer wheel) 32B Hold piece (for inner wheel) 33 Holder operation piece 33A Holder operation piece (for outer wheel) 33B Holder operation piece (for inner wheel) 35A Clamp bolt outer cylinder (for outer wheel) 35B Clamp bolt inner cylinder (for inner wheel) 40 Pivot bracket 41 Pivot axis 42 Operating rod 42A Auxiliary control rod 43 Magnet 101 Foundation 112 Post Frame

Claims

1. A movable base; The lifting stand is supported on the base so as to be freely raised and lowered. The lifting platform is provided with a pair of parallel rack arms for supporting the wheels, The rack arm is provided with a tire holder that is fitted to a side of a wheel supported in a support space formed by the pair of rack arms, The tire holder includes a holder rod movably supported on each rack arm, The holder rod is provided with a holding piece at a front portion and a holder operation piece at a rear hand side. A wheel dolly with improved operability, characterized in that the holder rod is supported so as to be slidable in the front-rear direction along the rack arm and rotatable about the axis of the holder rod.

2. 2. A wheel dolly with improved operability according to claim 1, wherein the pair of rack arms are provided with bearing rollers on the opposing inner sides for rollingly supporting the wheels.

3. A wheel dolly with improved operability as described in claim 1 or 2, characterized in that the tire holders provided on each rack arm are configured to support wheels in a double tire state, and include an outer wheel tire holder that acts on an outer wheel attached to the outer side of the vehicle in the vehicle width direction, and an inner wheel tire holder that acts on an inner wheel attached to the inner side of the vehicle in the vehicle width direction.

4. the holder rod of the tire holder for the inner wheel has a total length extending from a rear hand position to a front end side of the rack arm, On the other hand, the holder rod of the tire holder for the outer wheel has a length dimension from the rear hand position toward the front that is shorter than that of the holder rod for the inner wheel, 4. A wheel dolly with improved operability according to claim 3, wherein the holder rod for the inner wheel is nested within the holder rod for the outer wheel.

5. 3. A wheel dolly with improved operability according to claim 1 or 2, characterized in that a steering post for moving the wheel dolly is provided upright on the hand side of said rack arm.

6. 6. A wheel dolly with improved operability according to claim 5, wherein the steering post is provided with a support hole at a lower portion thereof for supporting the holder rod so as to be rotatable or slidable.

7. 7. A wheel dolly with improved operability according to claim 6, wherein the steering post is provided with a clamp bolt for fixing a holder rod.

8. In a configuration in which a holder rod for an inner wheel is nested inside the holder rod for the outer wheel, The steering post is provided with a clamp bolt for fixing a holder rod for an outer wheel, 5. A wheel dolly with improved operability according to claim 4, characterized in that the holder rod for the outer wheel is provided with a clamp bolt for fixing the holder rod for the inner wheel.

9. A wheel dolly with improved operability as described in claim 1 or 2, characterized in that the holder operating piece for rotating or sliding the holder rod is lever-shaped and formed to protrude radially outward from the holder rod, and the holder operating piece and the hold piece are formed to protrude in the same direction when viewed from the rotation axis of the holder rod.

10. The rack arm is formed of a rigid member having an L-shaped cross section, A wheel dolly with improved operability as described in claim 2, characterized in that the pair of left and right rack arms are arranged so that the pocket portions, which are the inside of the L-shaped cross section, face each other inward, and a support roller is provided in this pocket portion and a holder rod is provided on the outside of the pocket portion.

11. When the holding piece is raised and applied to the side of the wheel, A wheel dolly with improved operability as described in claim 10, characterized in that after the hold piece is rotated to enter the support space, the hold piece is further abutted against the upper end of the L-shaped cross-section of the rack arm to set and maintain the upright position of the hold piece.

12. 3. A wheel dolly with improved maneuverability according to claim 2, characterized in that the support roller has a carry-up sleeve fitted thereon and configured to be retractable from a support position toward the hand side.

13. The base is a single-post type that supports the central portions of a pair of left and right rack arms so that they can be raised and lowered.

3. A wheel dolly with improved operability according to claim 1 or 2, characterized in that the lifting platform is rotatably mounted on the base in a plan view.

14. A wheel dolly with improved operability as described in claim 1 or 2, characterized in that the base is a forklift-like parallel post type in which a pair of left and right rack arms can be freely raised and lowered relative to a post frame arranged upright on the left and right.

15. A wheel dolly with improved operability as described in claim 1 or 2, characterized in that the base is mounted on a movable platform that moves in the fore-and-aft direction of the vehicle on rails laid on the stall floor, and the base is configured to be freely moved in the width direction of the vehicle on the movable platform.

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