JP7768906B2 - Vehicle charger unit - Google Patents

Description

The present invention relates generally to charger units. More particularly, but not exclusively, the present invention relates to charger units for vehicles.

Generally, electric vehicles use one or more batteries as a power source to power the traction motor and thereby drive the vehicle. During vehicle towing, the batteries become discharged and need to be replaced or recharged. Replacing the batteries is not a preferred option for vehicle users due to their heavy weight. Therefore, to make things easier for customers, manufacturers offer rechargeable types of batteries, allowing vehicle users to easily charge their batteries whenever needed. To charge the batteries, a power supply is required from a charging station or a household power source. A charger unit is required to connect the battery and the power source and allow charge to be transferred from the charging station/household power source to the battery. Charger units are mainly of two types: off-board chargers and on-board chargers. Off-board chargers need to be carried by the user and require storage space within the vehicle. Off-board chargers are generally large in size and not convenient to carry. Therefore, on-board chargers are preferred.

However, with compact layouts, particularly in two-wheeled vehicles, packaging the charger unit and mounting it in a convenient location presents challenges. Electric and hybrid vehicles, in particular, involve additional electrical parts, making vehicle packaging even more challenging. In step-through electric vehicles, style panels cover all vehicle components, thereby further limiting the available space for packaging.

The size of the charger unit is proportional to the battery size; i.e., the larger the vehicle capacity, the larger the battery required, and therefore the larger the charger unit required, which further complicates packaging challenges due to space and assembly time requirements.

Generally, in two-wheeled electric vehicles, the battery is placed in the rear area of the vehicle, and the charging unit is placed in either the front, middle, or rear area of the vehicle. In scenarios where the charger unit is placed in the front of the vehicle, some power loss, also known as wiring harness loss, occurs due to the long cable length connecting the battery and the charger unit. In other cases where the charger unit is placed in the middle area of the vehicle, it is difficult to access the charger unit and perform maintenance work. In cases where the charger unit is disposed in the rear area of the vehicle, utility space is compromised.

In addition, the appearance of the vehicle is also an important factor for customers considering purchasing a vehicle. Therefore, the vehicle's compact packaging must be efficient without compromising its appearance.

Therefore, there is a need for an improved layout and configuration of a charger unit in a compact vehicle that overcomes all of the above challenges and other challenges of known technologies. What is needed is an improved location and mounting arrangement for a charger unit that meets requirements related to charger stability, minimum connection length between the charger and the battery, and user accessibility to the charging slot, can be incorporated into the existing layout of a motorcycle, and minimizes assembly and maintenance time.

To achieve one or more of the above-mentioned and other related objectives, the present invention provides a vehicle having a charger unit powered by a battery and located in a safe and secure location for optimal performance. The mounting location and configuration of the charger unit also facilitate easy access, assembly with fewer parts, and maintainability. The charger unit provided in the present invention is comprised of fewer parts, which increases durability and allows for more efficient cooling of the charger unit, resulting in a lighter weight.

The present invention provides a two-wheeled vehicle including a frame and a charger unit. The frame includes a front portion and a rear portion. The charger is disposed in the rear portion of the frame. The charger unit is placed in an inclined position so that a first imaginary line extending from the bottom surface of the charger unit in a downward and forward direction along the longitudinal direction of the vehicle intersects a second imaginary line extending from the steering assembly in its axial direction in an area located forward of the front axle point of the front wheels when viewed from the side of the vehicle. The charger unit is oriented in an inclined position when viewed from the side of the vehicle to ensure that the utility space of the utility box and the clearance of the rear wheels are not compromised and do not interfere with the function of the two-wheeled vehicle. If the charger is placed in a horizontal orientation consistent with the longitudinal direction of the vehicle, the charger unit will occupy some of the utility space of the storage box, reducing or eliminating the size of the utility box. If the charger is placed in a vertical orientation perpendicular to the longitudinal direction of the vehicle, the charger unit will obstruct the available clearance of the rear wheels, which is undesirable. Therefore, by configuring the charger unit in an inclined position between a horizontal plane and a vertical plane, the charger unit can be packaged and mounted in a compact space and with a compact layout without compromising the layout and arrangement of parts within that area.

1 is an exemplary diagram of a two-wheeled vehicle. 1 is an exemplary diagram of a mounting location for a charger unit. 1 is an exemplary partial front perspective view of a vehicle having a charger unit. FIG. 1 is an exemplary partial rear perspective view of a two-wheeled vehicle. FIG. 10 is an exemplary exploded view of a utility box with a charger unit. 1 is an exemplary enlarged partial perspective view of a charger unit with a charger assembled within a vehicle. FIG. FIG. 1 is an exemplary diagram of a cooling arrangement for a charger unit located in the rear of a vehicle. FIG. 1 is an exemplary partial rear exploded perspective view of a vehicle with a charger assembled inside a casing on the vehicle. FIG. 1 is an exemplary perspective view of a charger. FIG. 2 is an exemplary side view of a charger. FIG. 2 is an exemplary perspective view of a casing of a charger unit.

The following detailed description will be given with reference to an embodiment of a saddle-type two-wheel scooter using the accompanying drawings. The same numbers are used throughout the drawings to refer to similar features and components.

In one embodiment of the present invention, the rear portion of the frame includes a left rear frame and a right rear frame, and the charger unit is disposed between the left rear frame and the right rear frame. In another embodiment of the present invention, the battery charger unit is disposed between the pair of rear shock absorbers below the seat assembly. The battery charger unit is positioned laterally offset from the center of the two-wheeled vehicle.

Another embodiment of the present invention provides a charging input port on the rear side of a charger unit placed in the rear portion of a vehicle to make it accessible for charging. To ensure the accessibility of the charging input port, an opening is provided in the rear portion of the vehicle's rear panel, located below the rear seat handle and above the rear tail lamp assembly of the two-wheeled vehicle. This mounting configuration of the charger unit eliminates undesirable bending of the charger input port cable, thus facilitating a direct connection between the charging input port and the charging gun/charging point. This reduces wear and tear on the cable and input port due to use, increasing their lifespan.

According to another embodiment of the present invention, mounting of the charger unit is accomplished using a minimal number of parts. The charger unit is mounted by a single mounting point at the front portion of the rear cross bridge, and multiple mounting points are provided within the rear portion of the rear cross bridge member, which is positioned between the left and right rear frame members of the two-wheeled vehicle. This mounting configuration allows for efficient mounting of the charger unit on the vehicle, and the mounting scheme therefore uses a minimal number of mounting means. If the charger unit were placed in a horizontal orientation rather than an inclined orientation, four or more mounting means would be required to secure the charger unit in place. Therefore, this mounting scheme and layout reduces the number of mounting means required to support the charger unit.

Another embodiment of the present invention provides a fan for forced cooling of a charger unit mounted on the upper portion of the rear fender. The axis of the cooling fan is normal to the bottom surface of the charger unit. The above configuration guides fresh air into the inside of the charger unit for cooling. The charger unit is provided with multiple cutouts near the cooling fan, which allow hot air to be expelled from the charger unit, keeping it cool. However, in alternative embodiments, the fan can be mounted anywhere else within the rear portion of the two-wheeled vehicle so that air can reach and exit the charger unit for cooling purposes.

According to another embodiment of the present subject matter, the fan is placed in an inclined position along with the charger unit so that hot air exiting the charger unit spreads into the available open space around the charger unit. This helps reduce the temperature of elements surrounding the charger unit.

Another aspect of the present invention is to provide a charger unit for a two-wheeled vehicle, the charger unit having a charger, an input extension protruding outward from a rear end of the charger unit, an output extension protruding outward from a front end of the charger unit, and a casing for housing the charger, the casing including a first slot for the input extension and a second slot for the output extension.

According to another embodiment of the present invention, a plurality of cooling fins are provided on the charger. The cooling fins are arranged together to form a trapezoidal shape in side view so that the charger unit fits inside the casing. The cooling fins arranged in this manner provide sufficient cooling to the charger with improved packaging within the charger unit.

According to another embodiment of the present invention, the charger unit input extension includes a first protruding lug surface and a second protruding lug surface. The casing includes multiple cutouts for air flow to ensure cooling of the charger placed inside the casing. The multiple cutouts incorporated into the casing also act as an arrester to limit rotation of the charger unit.

According to another embodiment of the present invention, the first slot of the casing includes a first casing surface and a second casing surface that are perpendicular to each other. To constrain the degree of freedom of the charger unit, the first casing surface abuts the first protruding lug surface, and the second casing surface abuts the second protruding lug surface of the charger input extension. This ensures that the charger unit does not move inside the casing, thus constraining its movement.

According to another embodiment of the present invention, a charger unit having a casing includes upper and lower portions attached to one another. The lower portion has a bottom surface and a plurality of side surfaces extending upward from the bottom surface of the casing. The lower portion opens from one side of the casing. The upper portion extends at an angle upward from the front of the lower portion toward the rear of the casing, creating space inside the casing for accommodating a charger. The casing includes a plurality of cutouts on the upper and lower portions. These cutouts created in the casing reduce the weight of the casing, resulting in a lightweight charger unit.

According to another embodiment of the present invention, the first slot for the input extension and the second slot for the output extension are provided at the junction of the bottom surface and the multiple side surfaces of the casing.

According to another embodiment of the present invention, the casing is provided with an attachment point on the upper portion of the inclined upper portion, and a two-point attachment portion is disposed on the rear end of the lower portion extending upward from the surface of the lower portion.

According to another embodiment of the present invention, the charger unit includes a front mounting means provided on a front portion of one end of the rear crossbridge member and a plurality of second mounting means provided on a distal end of the rear crossbridge member. Removing the distal end mounting means allows pivotal rotation of the charger unit along the front point mounting, thereby facilitating swinging movement of the charger unit and facilitating assembly and disassembly from compact spaces. An embodiment of the present invention will now be described in detail with reference to an embodiment in a scooter-type two-wheeled electric vehicle in conjunction with the accompanying drawings. However, the present invention is not limited to this embodiment.

FIG. 1 exemplarily illustrates a two-wheeled vehicle 100. The two-wheeled vehicle 100 has a front portion F and a rear portion R. The front portion F of the vehicle 100 includes a head tube (not shown), a down tube (not shown) extending from the head tube (not shown), a front shock absorber (not shown), a steering assembly (not shown), and a front wheel 106. The rear portion R of the vehicle 100 includes a left rear frame (not shown), a right rear frame (not shown), a seat assembly 105, a rear wheel 107, a pair of shock absorbers 109 (one shown), a swing arm 108, and a rear seat handle 144. The front portion F further includes a pair of horizontal extensions extending rearward from the down tube (not shown), and the rear portion R includes an inclined rearward upward extension that extends horizontally rearward from the horizontal extensions extending from the down tube (not shown). The front portion F of the two-wheeled vehicle 100 has a front panel 103 for covering the front portion of the vehicle 100. The down tube (not shown) of the vehicle 100, along with the front suspension (not shown), is connected to the front wheel 106. A seat assembly 105 is mounted on a pair of left and right rear frame members (not shown). The lower portion of the seat assembly 105 is covered by a side panel 151 and a rear panel 104. The rear portion R has a pair of shock absorbers 109 connected at one end to the rear frame of the vehicle 100, and the other end of the shock absorbers 109 is connected to the axle of the rear wheel 107. A swing arm 108 is connected at one end to the frame of the vehicle 100 in the longitudinal direction of the vehicle 100, and the other end is connected to the axle of the rear wheel 107. A rear seat handle 144 is provided on the rear portion R of the seat assembly 105 to support a rider in the rear seat of the vehicle 100.

FIG. 2 shows an exemplary mounting location for the charger unit 112. The charger unit 112 is positioned at an angle such that a first imaginary line 119 extending from the bottom surface 115 of the charger unit 112 in a downward, forward direction along the longitudinal direction of the vehicle intersects a second imaginary line 120 extending from the steering assembly 145 in the axial direction thereof , located forward of the front axle points of the front wheels 106, at an intersection point 121. An axis 122 is a vertical line passing through the front axle points, and the second imaginary line 120 intersects with the axis 122 and the first imaginary line 119. This angled mounting configuration reduces the number of mounting points, thereby further reducing parts costs. Additionally, packaging and mounting of the charger unit 112 is possible within the existing layout without requiring any modification or displacement of the vehicle's existing collection system. This also results in better utility space or allows a larger charger unit 112 to be accommodated.

FIG. 3 exemplarily illustrates a partial front perspective view of the vehicle 100 having a charger unit 112, and FIG. 4 exemplarily illustrates a partial rear perspective view of the two-wheeled vehicle 100. The two-wheeled vehicle 100 includes a right rear frame 110(a) and a left rear frame 110(b) connected by a rear cross-bridge 111 at the end of the rear section R of the vehicle 100. The charger unit 112 includes a charger 114, which is used to charge a battery (not shown) by using an external power source (not shown) and connecting it to a charge port 118 to initiate charging of the battery (not shown). To facilitate connection between the charger unit 112 and the external power source, the charge port 118 is provided on the rear side of the charger unit 112. An opening 116 (shown in FIG. 4) in the rear panel 104 of the rear section R of the vehicle 100 is provided below a rear seat handle 144 (shown in FIG. 3) that supports a passenger in the rear seat. A charging port 118 is taken out of the section of the opening 116 for connection to an external power source. The charger unit 112 has a charging port 118 connected to the side of the charger unit 112 for connecting the charger 114 to a charging gun/charging point at a charging station/domestic power source. This opening 116 in the rear portion R allows for easy access while the vehicle 100 is charging.

FIG. 5 exemplarily illustrates a partially exploded perspective view of a vehicle having a utility box 117 along with a charger unit 112. The charger unit 112 is positioned laterally off-center on the two-wheeled vehicle 100 and is disposed below the seat assembly (not shown) between the pair of rear shock absorbers (not shown in this figure). The charger unit 112 is disposed in an inclined orientation by multiple fasteners so as not to intrude into the utility space of the utility box 117. The mounting of the charger unit 112 also ensures that it does not interfere with the rear wheels 107, thereby preserving the clearance of the rear wheel wells. Therefore, by placing the charger unit 112 in an inclined position between a horizontal plane and a vertical plane, the charger unit 112 can be packaged and mounted within an existing layout in a compact layout using minimal space and without displacing any of its neighboring parts. This mounting location ensures easy access and maintenance for the customer. During maintenance, the utility box 117 is removed to access the charger unit 112. After removing the utility box, the charger unit mounting portions 124(b) in the rear are removed, then the charger unit is rotated around the front mounting portion 124(a), which acts as a hinge, and then the charger unit is removed from the vehicle. In the entire process, no side panels (not shown) need to be removed from the vehicle 100 to access and remove the charger unit 112; only the utility box 117 is removed. Removing the utility box is typically easy in terms of access and removal with simple tools.

FIG. 6 exemplarily illustrates an enlarged, perspective view of the charger unit 112 with the charger 114 installed within the vehicle. The charger unit 112 is attached using multiple fasteners. The charger unit 112 is attached via a front mounting portion 124(a) within the front portion of the rear cross bridge 111 and two charger unit mounting portions 124(b) within the rear portion of the rear cross bridge 111, which are located between the right rear frame 110(a) and the left rear frame 110(b) of the two-wheeled vehicle 100. This mounting configuration achieves safe and secure attachment with a minimum number of mounting fixtures. Furthermore, existing components such as the rear cross bridge 111 are configured with mounting fixtures for the charger unit 112 on the vehicle 100 without requiring the addition of additional parts to the vehicle 100. If the charger unit 112 were placed in a horizontal orientation rather than an inclined orientation, four or more mounting locations would be required to secure the charger unit 112 in place. Therefore, the mounting locations according to the present invention significantly reduce the number of fasteners required to support the charger unit 112. The charging port 118 is provided on the side of the charger unit 112 so that the cable 146 of the charging port 118 does not bend during operation, thereby ensuring a long life for the cable 146 of the charging port 118 and minimizing transmission losses in the wiring harness. Shock absorber mounting brackets 147 are also provided on the right rear frame 110(a) and left rear frame 110(b) of the vehicle 100 adjacent to the charger unit 112. The shock absorber mounting brackets 147 ensure that vibrations or shocks are evenly distributed over the frame and do not affect the charger unit 112.

FIG. 7 shows an exemplary cooling arrangement for a charger unit 112 located at the rear of the vehicle 100. A cooling fan 150 is provided in the inner portion of the rear fender 148 above the rear wheels 107 to cool the charger unit 112. The axis 152 of the cooling fan 150 is normal to the bottom surface of the charger 115 (shown in FIG. 2) of the charger unit 112. This configuration opens a path for fresh air 153 to enter the interior of the charger unit 112 to cool the charger 114. The casing (not separately shown) is provided with cutouts or openings to allow hot air 154 to escape from the charger unit 112. The hot air 154 blowing toward the utility box 117 is deflected by the rear wall of the utility box 117 and directed downward toward the ground. The hot air 154 leaving the charger unit 112 escapes through all of the cutouts provided in multiple directions, ensuring that the temperature of the charger unit 112 is kept at a minimum. The location of the cooling fan 150 on the rear fender 148 protects the cooling fan from water or foreign objects. Additionally, the wheel hugger 149 also protects the cooling fan from mud, splashed water, etc., and limits foreign objects from or around the rear wheel 107 from reaching the cooling fan 150. The cutouts in the charger unit 112 also help reduce weight, thereby reducing cost as well as weight. In another embodiment, the cooling fan 150 is mounted on lugs integrally formed with the rear fender 148, thereby helping to minimize the number of parts required to mount the cooling fan 150. This mounting location configuration is possible with different shapes and sizes of the charger unit 112.

FIG. 8 exemplarily illustrates a partial exploded perspective view of the rear of the vehicle with the charger 114 assembled inside the casing 13 on the vehicle, and FIGS. 9(a) and 9(b) exemplarily illustrate a perspective view and a side view of the charger 114. The charger unit 112 includes the charger 114, an input extension 125 protruding outward from the rear end of the charger 114, an output extension 126 protruding outward from the front end of the charger 114, and the casing 113. The charger 114 is disposed inside the casing 113 and mounted on a rear crossbridge (not shown) of the rear frame of the two-wheeled vehicle 100. The charger 114 is configured with a plurality of cooling fins 129 on its surface for cooling the charger unit 112. In one embodiment, the height of the cooling fins 129 gradually increases, then remains constant at a fixed length, and then gradually decreases to form a trapezoidal shape. The trapezoidal shape of the cooling fins 129 allows the charger 114 to be easily guided to pivot compactly inside the casing 113 while maximizing the number of cooling fins. The cooling fins 129 provide sufficient cooling and ensure that cooling efficiency is maintained by having cooling fins 129 of various sizes to facilitate improved packaging space for the charger 114 and further ensure optimal cooling of the charger 112. However, the structure of the cooling fins 129 and the shape of the casing 113 of the battery charger unit 112 may vary based on the layout requirements of the vehicle 100. The casing 113 is provided with a plurality of cutouts 132 to allow air flow to ensure cooling of the charger 114 placed inside the casing 113. The casing 113 that houses the charger 114 includes a first slot 127 for the input extension 125 and a second slot 128 for the output extension 126. The input extension 125 includes a first protruding lug surface 130 and a second protruding lug surface 131. The first slot 127 of the casing 113 includes a first casing surface 133 and a second casing surface 134 that are perpendicular to each other. To constrain the rotational degree of freedom of the charger unit 112, the first casing surface 133 abuts the first protruding lug surface 130, and the second casing surface 134 abuts the second protruding lug surface 131 of the input extension 125. This ensures that the charger unit 112 does not move inside the casing 113, thus constraining its movement and securing the charger unit 112 inside the casing 113.

10 exemplarily illustrates a perspective view of the casing 113 of the charger unit 112. In one embodiment, the casing 113 is constructed of a polymer material having a hollow shape for accommodating the charger unit (not shown). The polymer material provides the casing 113 with the necessary strength and flexibility for mounting the charger unit (not shown) on the vehicle 100. The casing 113 includes an upper portion 135 and a lower portion 136 attached to each other. The lower portion 136 and the upper portion 135 of the casing 113 may be integrally attached or may be removably attachable. The lower portion 136 has a bottom surface 137 and a plurality of side surfaces 138 extending perpendicularly from the bottom surface 137. In this embodiment, the lower portion 136 has three side surfaces, and the lower portion 136 opens from one side of the casing 113. The three sides restrain the charger (not shown) inside the casing 113 to prevent it from tipping over. The charger (not shown) is slidably inserted into the open side of the casing 113. The upper portion 135 extends at an angle upward from a front surface 139, which is part of the lower portion 136, toward the rear of the casing 113, creating space inside the casing 113 for accommodating the charger (not shown). The casing 113 includes multiple cutouts 132 on the upper and lower portions 135, 136 for cooling purposes. A first slot 127 for an input extension (not shown) and a second slot 128 for an output extension (not shown) are provided at the junction of the bottom surface 137 and the multiple sides 138 of the casing. First and second slots 127 and 128 are provided at the bottom junction to facilitate an installation connection that ensures the wiring (not shown) is not twisted or rotated, thus ensuring its durability over its lifespan. Casing 113 is provided with an attachment point 140 on the upper portion of inclined upper section 135, and a two-point attachment 141 is provided on the distal end of lower section 136 that extends upward from the surface of lower section 136. Numerous other improvements and modifications may be incorporated herein without departing from the scope of the present invention.

100 two-wheeled vehicle 101 frame F front portion of 101 R rear portion of 101 102 down tube of 101 103 front panel of F 104 rear panel of R 105 seat assembly of 100 106 front wheel of 100 107 rear wheel of 100 108 swing arm of 100 109 rear shock absorber of 100 110(a) left rear frame of 100 110(b) right rear frame of 100 111 rear cross bridge of 100 112 charger unit 113 casing of 114 114 charger of 112 115 bottom surface of 112 116 opening on 104 117 utility box 118 charging input port of 114 119 first imaginary line extending from 115 120 A second imaginary line 121 proceeding from 122 is the intersection of 119 and 120.
123 Rear side 124(a) Front mounting portion 124(b) Multiple charger unit mounting portions 125 Input extension portion of 114 126 Output extension portion of 114 127 First slot on 113 128 Second slot on 113 129 Cooling fins on 114 130 First protruding lug surface of 125 131 Second protruding lug surface of 125 132 Multiple cutouts for cooling 133 First casing surface of 127 134 Second casing surface of 127 135 Upper portion of 113 136 Lower portion of 113 137 Bottom surface of casing 138 Multiple side surfaces of 113 139 Front surface of 113 140 Mounting points on 113 141 Two-point mounting portion on 113 143 Rear fender of 100 144 Rear seat handle at R 145 Steering assembly at F 146 Cable of 112 147 Shock mounting bracket of 109 148 Rear fender 149 Wheel hugger 150 Cooling fan for 112 151 Side panel of 100 152 Shaft of 150 153 Fresh air from 150 154 Hot air exiting 150

Claims (11)

a charger (114);
an input extension (125) protruding outward from the rear end of the charger (114);
an output extension (126) projecting outward from the front end of the charger (114);
a casing (113) for housing the charger (114), the casing including a first slot (127) for the input extension (125) and a second slot (128) for the output extension (126). 2. The charger unit (112) of claim 1, wherein cooling fins (129) are provided on the charger (114), the cooling fins (129) being arranged together to form a trapezoidal shape of the charger (114) in a side view. 2. The charger unit (112) of claim 1, wherein the casing (113) includes a plurality of cutouts (132) for air flow to ensure cooling of the charger ( 114 ) placed inside the casing (113). 2. The charger unit (112) of claim 1, wherein the input extension (125) includes a first protruding lug surface (130) and a second protruding lug surface (131), and the first slot (127) of the casing (113) includes a first casing surface (133) and a second casing surface (134) that are perpendicular to each other, whereby the first casing surface (133) abuts the first protruding lug surface (130) and the second casing surface (134) abuts the second protruding lug surface (131) of the input extension (125) to constrain a rotational degree of freedom of the charger unit (112). 2. The charger unit (112) of claim 1 , wherein the casing (113) is at least partially open from one side, and the casing (113) includes an upper portion (135) and a lower portion (136) attached to one another. 6. The charger unit (112) of claim 5 , wherein the lower portion (136) has a bottom surface (137) and a plurality of side surfaces (138) extending upwardly from the bottom surface (137). 6. The charger unit (112) of claim 5, wherein the upper portion (135) extends obliquely upward from the front surface (139) of the lower portion (136) toward the rear of the casing (113) to create a space inside the casing (113) for accommodating the charger (114). 4. The charger unit (112) of claim 3 , wherein the plurality of cutouts (132) included in the casing (113) are provided on an upper portion (135) and a lower portion (136). 7. The charger unit (112) of claim 6, wherein the first slot (127) for the input extension (125) and the second slot (128) for the output extension (126) are provided at a junction of the bottom surface (137) and the plurality of side surfaces (138) of the casing ( 113). 6. The charger unit (112) of claim 5, wherein the casing (113) is provided with an attachment point (140) at the top of the inclined upper portion (135) and a two-point attachment portion ( 141 ) is disposed on the distal end of the lower portion (136). a front attachment means (124(a)) provided on the front portion of the rear cross-bridge member (111);
a plurality of second attachment means (124(b)) provided on a distal end extending rearward from the front portion of the rear cross-bridge member (111);
A charger unit (112) wherein removal of said plurality of second attachment means (124(b)) allows pivotal rotation of the charger unit (112) along said front attachment means (124(a)).