Hand truck

Abstract

To provide a hand-pushed carriage capable of achieving easy and stable start and operation thereof, without need for electric power assist as well as lever operation separated from a handle and pedaling.SOLUTION: When a handlebar 18H of a movable handle 18 is grasped together with clutch bars 33a, 33b and pushed ahead (or pulled backward), the movable handle 18 is inclined forward (or rearward) with a handle support shaft 19R of a lower end part of a pillar 18R thereof as a supporting point. The operating force accompanied with the inclination of the movable handle 18 is transmitted as a rotational force to a forward side (or a backward side) of a ratchet type first gear 28R through a clutch plate 32R coaxial to the handle support shaft 19R, and a rear wheel 15R is rotated forward (or rotated backward) through a second gear 30R and a third gear 31R. A carriage 1 is started in a forward direction (or a backward direction).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a hand truck. [Background technology]

[0002] 2. Description of the Related Art Hand trucks are used to transport cargo at construction sites, factories, and the like.

[0003] The trolley is operated by a human pushing the handle, but when starting a stationary trolley with a load, the heavier the load, the more force is required.The force required to start also increases depending on the condition of the floor along the transport route, such as small steps or slopes.

[0004] On the other hand, there are electrically assisted trolleys equipped with a motor and battery, but these have the problems of being expensive and difficult to transport due to the weight of the vehicle itself. Furthermore, electrically assisted trolleys are difficult to control because it is difficult to adjust the speed and they tend to suddenly start or accelerate depending on the operator's operation, making them difficult to operate. Another problem is that the electrically assisted function is lost when the battery runs out of charge.

[0005] Therefore, a trolley equipped with a manual start-up assist mechanism without being equipped with an electric assist function such as a motor or battery has been considered. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Utility Model Registration No. 3222872 [Patent Document 2] Japanese Patent Application Laid-Open No. 2019-151154 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-96692 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional trucks equipped with a manual start-up assist mechanism obtain starting assistance by rotating the wheels using the force required to operate a lever or to depress a pedal, separate from the handle used to push the truck.

[0008] In order to move the trolley stably, the heavier the load, the more the worker needs to be in a stable position and grip the handle firmly with both hands to operate it. However, if force is required to operate levers or press on pedals when starting, the strength required to operate the handle in a balanced manner and the worker's own position will become unstable, and the movement of the trolley may become unstable even with starting assistance.

[0009] To provide a hand truck that can be easily and stably started and moved without the need for electric assist, and without the need to operate a lever separate from the handle or to step on a pedal. [Means for solving the problem]

[0010] The hand truck of the embodiment includes: The loading platform and Wheels supported on the rear surface of the loading platform so as to be rotatable in the front-rear direction of the loading platform; a handle that is provided upright on the loading platform and supported so as to be tiltable forward or backward with a lower end thereof as a fulcrum; a handle operation force transmission mechanism that is provided between a lower end of the handle and the wheels and that transmits a force that rotates the lower end of the handle as the handle is tilted forward or backward as a force that rotates the wheels forward or backward. 、 The handle operation force transmission mechanism includes: a handle support shaft that supports a lower end of the handle on the carrier; a ratchet gear that is supported coaxially with the handle support shaft and that can rotate only forward when the handle is tilted forward and can rotate only backward when the handle is tilted backward; a clutch plate that is supported coaxially with the handle support shaft, that rotates forward in conjunction with the rotation of the lower end when the handle is tilted forward, and that rotates rearward in conjunction with the rotation of the lower end when the handle is tilted rearward, and that transmits the forward rotation or the rearward rotation by pressing against the ratchet gear; a wheel gear supported coaxially with the wheel support shaft and rotating together with the wheel; and at least one intermediate gear meshed between the ratchet gear and the wheel gear. . [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a right side view showing the configuration of the hand truck 1 of the embodiment as viewed from the right side. [Figure 2] 2 is a rear view showing the configuration of the hand truck 1 of FIG. 1 as seen from behind. [Figure 3] 10A and 10B are diagrams illustrating the movement of the movable handle 18 and the handle lock bar 21 relative to the handle support plates 20R1 and 20L1 and their handle movable holes 22. [Figure 4] A diagram explaining the relationship between the rotation of the ratchet-type first gears 28R, 28L due to tilting of the movable handle 18 and the rotation of the rear wheels 15R, 15L from the ratchet-type first gears 28R, 28L via the second gears 30R, 30L and the third gears 31R, 31L. [Figure 5] 10A and 10B are diagrams illustrating the relationship between the movement of the clutch bars 33a and 33b of the movable handle 18 and the movement of the clutch plates 32R and 32L relative to the ratchet-type first gears 28R and 28L. [Figure 6] 10 is a view illustrating the operation of releasing the braked state of the rear wheels 15R, 15L by the brake release pedal 48 of the wheel braking mechanism, as viewed from the right side of the bogie 1. FIG. [Figure 7] 7 is an enlarged view showing the relationship between the brake release pedal 48 and the lever engaging portion 44 of the foot lever 43 corresponding to the movement of releasing the braked state of the rear wheels 15R, 15L in FIG. 6. FIG. [Figure 8] 10 is a diagram illustrating the gear ratios of ratchet-type first gears 28R, 28L, second gears 30R, 30L, and third gears 31R, 31L that transmit the operating force for tilting the movable handle 18 as a rotational force of the rear wheels 15R, 15L. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a push cart according to an embodiment will be described with reference to the drawings.

[0013] (Configuration of handcart 1) FIG. 1 is a right side view showing the configuration of a hand truck 1 according to an embodiment as viewed from the right side.

[0014] FIG. 2 is a rear view showing the configuration of the hand truck 1 of FIG. 1 as seen from behind.

[0015] The hand truck 1 includes a loading platform 11 having a rectangular shape in plan view and extending longitudinally, and wheels (front right wheel 12R, front left wheel 12L, rear right wheel 15R, and rear left wheel 15L) provided at the four corners of the back of the loading platform 11.

[0016] The front wheels 12R, 12L are supported via front wheel support shafts (13R for the right front wheel and 13L for the left front wheel) by a pair of wheel support members (14R1, 14R2 for the right front wheel and 14L1, 14L2 for the left front wheel) that are erected on the underside of the loading platform 11 so as to sandwich the sides of the front wheels 12R, 12L. The front wheel support members 14R1, 14R2, 14L1, 14L2 are integrally mounted in pairs on the underside of the loading platform 11 so as to be horizontally rotatable, and support the front wheels 12R, 12L while allowing them to move freely in the direction of travel.

[0017] The rear wheels 15R, 15L are supported by a pair of wheel support members (17R1, 17R2 for the right rear wheel and 17L1, 17L2 for the left front wheel) fixed and erected on the underside of the cargo bed 11 so as to sandwich the sides of the rear wheels 15R, 15L, via a single axle 16 shared by both the left and right wheels. The rear wheels 15R, 15L are supported fixedly in the forward and backward directions.

[0018] The hand truck 1 also has an arch-shaped movable handle 18 that stands upright at the rear of the loading platform 11 corresponding to the positions of the rear wheels 15R, 15L. The movable handle 18 stands upright on the loading platform 11 so as to straddle the left and right outer sides between the rear wheels 15R, 15L in a U-shape, and is configured, for example, with hollow right and left support columns 18R, 18L that have a rectangular cross section, and a handle bar 18H that connects the left and right support columns 18R, 18L horizontally at the top.

[0019] The right support 18R and left support 18L of the movable handle 18 are supported by the loading platform 11 via handle support shafts 19R, 19L, whose lower ends penetrate the back surface of the loading platform 11 and are fixed, for example, at the height of the back surface of the loading platform 11 and facing in the left-right direction of the loading platform 11.

[0020] A space is formed in the loading platform 11, centered on the part where the right support pillar 18R and the left support pillar 18L pass through, as a hole of a certain length in the fore-and-aft direction and the width of the support pillars 18R, 18L. The support pillars 18R, 18L, i.e., the movable handle 18, are supported so that they can be tilted within a certain angle range in the fore-and-aft direction, with the handle support shafts 19R, 19L as fulcrums.

[0021] <Handle lock mechanism> In addition, rectangular handle support plates 20R1, 20R2, 20L1, 20L2 are erected on the rear surface of the cargo bed 11, along the left and right sides of the right support 18R and left support 18L of the movable handle 18, with a length in the front-to-rear direction that exceeds at least the range in which the right support 18R and left support 18L can be tilted.

[0022] Each of the handle support plates 20R1, 20R2, 20L1, 20L2 is formed with an identically shaped handle movable hole 22 that forms an inverted Y when viewed from the side. A single handle lock bar 21 is inserted through each of the handle movable holes 22 in the handle support plates 20R1, 20R2, 20L1, 20L2. The handle lock bar 21 penetrates the right support column 18R or the left support column 18L horizontally to the cargo bed 11 from the lower end of each column to a height corresponding to the handle movable hole 22.

[0023] The handle lock bar 21 is provided to be slidable in the up and down direction relative to the right support column 18R and left support column 18L of the movable handle 18 within a range corresponding to the height difference of the handle movable hole 22.

[0024] Here, the upward recess in the center of the handle movable hole 22, which is an inverted Y shape of the handle support plates 20R1, 20R2, 20L1, 20L2, is called the neutral recess (locked position) 22N, the recess sloping downward toward the front side is called the forward recess (forward position) 22F, and the recess sloping downward toward the rear side is called the rear recess (reverse position) 22B.

[0025] The handle lock bar 21 is configured by connecting three three-way springs 23F, 23B, 23N arranged in a Y shape with the tip end as a branching point to pins P1, P2, P3 corresponding to the vertices of the Y so that the tip end, which protrudes left and right through the handle movable hole 22, is normally fitted and held in a neutral recess (lock position) 22N of the handle movable hole 22, on a handle support plate 20R1 along the right end of the movable handle 18 and a handle support plate 20L1 along the left end.

[0026] Here, of the three-way springs 23F, 23B, 23N arranged in a Y shape on the handle support plates 20R1, 20L1 with the tip of the handle lock bar 21 as the branching point, the spring arranged between the rear pin P1 is the forward retraction spring 23F, the spring arranged between the front pin P2 is the reverse retraction spring 23B, and the spring arranged between the central lower pin P3 is the neutral spring 23N.

[0027] In addition, at both the left and right ends of the handlebar 18H of the movable handle 18, there are provided unlocking levers 24R, 24L which form an L shape facing diagonally upward and backward, with lever support shafts 25R, 25L provided laterally at the upper ends of the right support column 18R and the left support column 18L as fulcrums.

[0028] The rearward-facing tips of the unlocking levers 24R, 24L are connected to unlocking links 26R, 26L, which extend downward along the inside of the right support pillar 18R and the left support pillar 18L and abut against the side of the handle lock bar 21 from above.

[0029] The lower ends of the unlocking links 26R, 26L are connected to the handle lock bar 21 by a three-way joint 27 so as to form an inverted T shape when viewed from the front-rear direction of the cargo bed 11.

[0030] Here, the relationship between the movement of the unlocking levers 24R, 24L to the unlocking links 26R, 26L, the handle lock bar 21, and the handle movable holes 22 of the handle support plates 20R1, 20L1, and the movement of the movable handle 18 will be described.

[0031] FIG. 3 is a diagram illustrating the movement of the movable handle 18 and the handle lock bar 21 relative to the handle support plates 20R1, 20L1 and their handle movable holes 22. As shown in FIG.

[0032] When the lock release levers 24R, 24L are not operated (not pulled rearward), as shown in Figure 3(A), the handle lock bar 21 of the movable handle 18 is fitted into and held in the neutral recess (lock position) 22N of the handle movable hole 22 formed in the handle support plates 20R1, 20L1, and the movable handle 18 is fixed to the trolley 1.

[0033] When the unlocking levers 24R, 24L are operated (pulled rearward), the handle lock bar 21 is pushed downward against the spring force of the forward retraction spring 23F and the reverse retraction spring 23B via the unlocking links 26R, 26L, and is released from the neutral recess (lock position) 22N of the handle movable hole 22.

[0034] Here, when the handle bar 18H of the movable handle 18 is pushed forward to move the trolley 1 forward, the movable handle 18 tilts forward together with the handle lock bar 21 against the spring force B of the forward retraction spring 23F, as shown by arrow a in Figure 3(B).

[0035] Furthermore, when the handle bar 18H of the movable handle 18 is pulled backward to move the trolley 1 in reverse, the movable handle 18 tilts backward together with the handle lock bar 21 against the spring force F of the retraction spring 23B when moving backward, as shown by arrow b in Figure 3(C).

[0036] Furthermore, whether the trolley 1 is moving forward or backward, if the force applied by pushing and pulling the handle bar 18H becomes lighter as the trolley 1 gains speed after starting, the movable handle 18 is pulled back to the neutral position together with the handle lock bar 21 by the spring force B of the forward retraction spring 23F or the spring force F of the reverse retraction spring 23B, and as shown in Figure 3(A), the handle lock bar 21 fits again into the neutral recess (lock position) 22N of the handle movable hole 22, returning to a fixed state.

[0037] <Steering wheel operation force transmission mechanism> On the other hand, the bogie 1 is provided with ratchet-type first gears 28R, 28L, second gears 30R, 30L and third gears 31R, 31L that rotate in conjunction with the rear wheels 15R, 15L, along the side surfaces of the outer wheel support members 17R1, 17L1 of the left and right rear wheels 15R, 15L.

[0038] The ratchet-type first gears 28R, 28L are supported by a support shaft coaxial with the handle support shafts 19R, 19L at a position spaced apart inside the lower ends of the left and right support columns 18R, 18L of the movable handle 18, and switch between a state allowing only forward rotation, a state allowing only backward rotation, and a state allowing free forward and backward rotation depending on the switching position of a ratchet switch 28S (see Figure 4) described later that is provided on the side of the support columns 18R, 18L.

[0039] The second gears (relay gears) 30R, 30L are rotatably supported on second support shafts 29R, 29L erected on the side surfaces of the wheel support members 17R1, 17L1, and are provided below and meshed with the ratchet type first gears 28R, 28L.

[0040] The third gears (rear wheel gears) 31R, 31L are fixedly supported on the ends of the axles 16 of the rear wheels 15R, 15L, and are provided below and meshed with the second gears 30R, 30L, and rotate together with the rear wheels 15R, 15L and their axles 16.

[0041] Clutch plates 32R, 32L are provided between the lower ends of the left and right pillars 18R, 18L of the movable handle 18 and the ratchet-type first gears 28R, 28L to transmit the rotation associated with tilting the movable handle 18 (pillars 18R, 18L) in the forward and backward directions around the handle support shafts 19R, 19L as a fulcrum to the ratchet-type first gears 28R, 28L.

[0042] The clutch plates 32R, 32L are fixedly supported at the tips of cylindrical clutch operating pins 34R, 34L that protrude or sink from the lower ends of the left and right support columns 18R, 18L of the movable handle 18 along the handle support shafts 19R, 19L toward the ratchet type first gears 28R, 28L (see FIG. 5). The clutch plates 32R, 32L are arranged so that the clutch operating pins 34R, 34L protrude in response to the operation of sinking clutch bars 33a, 33b, which protrude from the front and rear side surfaces of the handle bar 18H, and are pressed against the side surfaces of the ratchet type first gears 28R, 28L by gripping the handle bar 18H.

[0043] Figure 4 is a diagram explaining the relationship between the rotation of the ratchet-type first gears 28R, 28L associated with tilting the movable handle 18 and the rotation of the rear wheels 15R, 15L from the ratchet-type first gears 28R, 28L via the second gears 30R, 30L and the third gears 31R, 31L.

[0044] As shown in Figure 4(A), when the ratchet switch 28S of the ratchet type first gears 28R, 28L is switched upward, the ratchet type first gears 28R, 28L are in a state where they can rotate freely back and forth, and the rear wheels 15R, 15L are in a state where they can rotate freely back and forth via the second gears 30R, 30L and the third gears 31R, 31L.

[0045] As shown in Figure 4(B), when the ratchet switch 28S is tilted forward and switched, the ratchet-type first gears 28R, 28L are in a state where they can only rotate forward, and the rear wheels 15R, 15L are in a state where they can only rotate in the forward direction F via the second gears 30R, 30L and the third gears 31R, 31L.

[0046] As shown in Figure 4(C), when the ratchet switch 28S is tilted backward and switched, the ratchet-type first gears 28R, 28L are in a state in which they can only rotate backward, and the rear wheels 15R, 15L are in a state in which they can only rotate in the reverse direction B via the second gears 30R, 30L and the third gears 31R, 31L.

[0047] The ratchet switch 28S of the ratchet type first gears 28R, 28L is switched forward in accordance with the movement of transmitting a forward rotational force f1 to the ratchet type first gears 28R, 28L by tilting the movable handle 18 forward as shown by arrow a in Figure 4(B) while causing the clutch operating pins 34R, 34L to protrude from the lower end of the movable handle 18 and pressing the clutch plates 32R, 32L against the sides of the ratchet type first gears 28R, 28L.

[0048] The forward rotational force f1 transmitted to the ratchet-type first gears 28R, 28L is transmitted as is as rearward rotational forces f2, f3 of the second gears 30R, 30L or as forward rotational force f4 of the third gears 31R, 31L, thereby obtaining an assisting force that rotates the rear wheels 15R, 15L forward FR, i.e., an assisting force that starts the trolley 1 in the forward direction F.

[0049] The forward rotation FR of the rear wheels 15R, 15L caused by the carriage 1 continuing to move forward F beyond the forward rotation of the ratchet-type first gears 28R, 28L in response to the forward tilt of the movable handle 18 is permitted by the forward free rotation of the ratchet-type first gears 28R, 28L, while the backward rotation BR of the rear wheels 15R, 15L is prevented, preventing reverse movement.

[0050] Furthermore, even if the movable handle 18 is tilted forward, when the pressure contact between the clutch plates 32R, 32L and the ratchet type first gears 28R, 28L is released, the ratchet switch 28S returns to its upward switching position, and the ratchet type first gears 28R, 28L return to a state in which they can freely rotate back and forth.

[0051] In addition, the ratchet switch 28S of the ratchet type first gears 28R, 28L is switched backward in accordance with the movement of transmitting a backward rotational force b1 to the ratchet type first gears 28R, 28L by tilting the movable handle 18 backward as shown by arrow b in Figure 4(C) while pressing the clutch plates 32R, 32L against the sides of the ratchet type first gears 28R, 28L.

[0052] The backward rotational force b1 transmitted to the ratchet-type first gears 28R, 28L is transmitted as is as forward rotational forces b2, b3 of the second gears 30R, 30L or as backward rotational force b4 of the third gears 31R, 31L, thereby obtaining an assisting force that rotates the rear wheels 15R, 15L backward BR, i.e., an assisting force that starts the trolley 1 in the backward direction B.

[0053] The rearward rotation BR of the rear wheels 15R, 15L caused by the carriage 1 continuing to move backward B beyond the amount of rearward rotation of the ratchet-type first gears 28R, 28L in response to the rearward tilt of the movable handle 18 is permitted by the backward free rotation of the ratchet-type first gears 28R, 28L, while the forward rotation FR of the rear wheels 15R, 15L is prevented, preventing reverse movement.

[0054] Furthermore, even if the movable handle 18 is tilted backward, when the pressure contact between the clutch plates 32R, 32L and the ratchet type first gears 28R, 28L is released, the ratchet switch 28S returns to its upward switching position, and the ratchet type first gears 28R, 28L return to a state in which they can freely rotate back and forth.

[0055] Therefore, when moving the trolley 1 forward, as shown in Figures 3(A)(B) and 4(A)(B), the lock release levers 24R, 24L are operated to release the handle lock bar 21 from its fixed state in the neutral recess (locked position) 22N of the handle movable hole 22, and the clutch plates 32R, 32L are pressed against the ratchet-type first gears 28R, 28L by operating the clutch bars 33a, 33b, and the movable handle 18 is grasped and pushed forward, and a starting assist force is obtained by tilting the movable handle 18 forward in response to the pushing, so that the trolley 1 can be easily and stably started and moved forward F even when loaded with heavy luggage.

[0056] Furthermore, when moving the trolley 1 backward, as shown in Figures 3(A)(C) and 4(A)(C), the lock release levers 24R, 24L are operated to release the handle lock bar 21 from its fixed state in the neutral recess (locked position) 22N of the handle movable hole 22, and the clutch plates 32R, 32L are pressed against the ratchet-type first gears 28R, 28L by operating the clutch bars 33a, 33b. At the same time, the movable handle 18 is grasped and pulled backward, and the movable handle 18 tilts backward in response to the pulling, providing a starting assist force, and the trolley 1 can be easily and stably started and moved backward B even when carrying a heavy load.

[0057] FIG. 5 is a diagram illustrating the relationship between the movement of the clutch bars 33a, 33b of the movable handle 18 and the movement of the clutch plates 32R, 32L relative to the ratchet type first gears 28R, 28L.

[0058] Figure 5(A1) is a partial right side view showing the rear of the trolley 1 including the movable handle 18 as viewed from the right side, Figures 5(A2) and (A3) are figures showing the configuration of the upper periphery E1 of the movable handle 18 including the clutch bars 33a, 33b of Figure 5(A1), Figure 5(B1) is a partial rear view showing the right rear part of the movable handle 18 of the trolley 1 from the right support pillar 18R to the right rear wheel 15R as viewed from behind, and Figures 5(B2) and (B3) are figures showing the configuration of the lower end periphery E2 of the right support pillar 18R including the ratchet-type first gear 28R and clutch plate 32R of Figure 5(B1).

[0059] As shown in FIGS. 5(A1), (A2), and (A3), the clutch bars 33a and 33b are provided on the front and rear side surfaces of the handle bar 18H of the movable handle 18 via a clutch spring 35 so as to be able to protrude and retract.

[0060] For example, when the handlebar 18H is gripped to sink the clutch bars 33a, 33b into the handlebar 18H against the spring force of the clutch spring 35 as shown by arrow g, the first vertical slide portion 37a built into the upper part of the support pillars 18R, 18L is pushed down as shown by arrow d1 via the first push-down links 36a, 36b connected to the first vertical slide portion 37a from the opposing back surfaces of the clutch bars 33a, 33b.

[0061] As shown in Figures 5(B2) and (B3), the first vertical sliding portion 37a is connected to the second vertical sliding portion 37b built into the lower part of the support pillars 18R and 18L via a second push-down link 38a, and the second vertical sliding portion 37b is also pushed down as shown by arrow d2 in conjunction with the pushing down of the first vertical sliding portion 37a.

[0062] The lower ends of the supports 18R, 18L incorporate left and right sliding sections 39 that are supported by the handle support shafts 19R, 19L and slide left and right, and cylindrical clutch operating pins 34R, 34L that protrude or sink in the direction of the ratchet type first gears 28R, 28L along the handle support shafts 19R, 19L are fixed to the inside of the left and right sliding sections 39 that face the ratchet type first gears 28R, 28L.

[0063] When the second vertical slide portion 37b is pushed down as shown by arrow d2, the horizontal slide portion 39 is slid inward as shown by arrow h via the direction change link 38b connected between it and the horizontal slide portion 39, and the clutch plates 32R, 32L are pressed against the ratchet-type first gears 28R, 28L via the clutch operating pins 34R, 34L.

[0064] As a result, the clutch plates 32R, 32L are provided so as to be pressed against the side surfaces of the ratchet type first gears 28R, 28L in response to the operation of the clutch bars 33a, 33b caused by gripping the handle bar 18H.

[0065] <Wheel braking mechanism> As shown in FIGS. 1 and 2, wheel braking members 40R, 40L are provided on the rear side of the rear portion of the loading platform 11 to press against the outer peripheral surfaces of the rear wheels 15R, 15L to stop the rotation of the rear wheels 15R, 15L.

[0066] The wheel braking members 40R, 40L are provided at both ends of a braking member support shaft 42 supported horizontally on the cargo bed 11 by a pair of left and right braking support parts 41R, 41L erected on the back surface of the cargo bed 11 inside the left and right rear wheels 15R, 15L and behind the rear wheels 15R, 15L, respectively, facing the outer peripheral surface of the rear wheels 15R, 15L.

[0067] The brake member support shaft 42 has a foot lever 43 that forms a U-shape toward the rear of the cargo bed 11 between the insides of the brake support portions 41R, 41L, and by rotating the foot lever 43 downward or upward with the brake member support shaft 42 as a fulcrum, the brake member support shaft 42 rotates backward or forward, and the wheel brake members 40R, 40L provided on both ends of the brake member support shaft 42 move between a position pressed against the outer peripheral surfaces of the rear wheels 15R, 15L (see Figures 6(A)(B)) and a position released (see Figures 6(C)(D)).

[0068] Lever lifting springs 45R, 45L are provided at the left and right ends of the foot lever 43 between the foot lever 43 and the rear surface of the loading platform 11, and a spring force is applied to the foot lever 43 to rotate the foot lever 43 upward.

[0069] In addition, a lever hook portion 44 is formed in the center of the foot lever 43, protruding upward by a certain width. When the lever hook portion 44 is in a stationary state with the lever hook portion 44 hooked into the first groove 48a of the brake release pedal 48 described later, the wheel braking members 40R, 40L are held in a position pressed against the outer peripheral surfaces of the rear wheels 15R, 15L via the brake member support shaft 42 (see Figure 6(A)), i.e., in a braking state. When the lever hook portion 44 is in a stationary state with the lever hook portion 44 hooked into the second groove 48b of the brake release pedal 48 described later, the wheel braking members 40R, 40L are held in a position removed from the outer peripheral surfaces of the rear wheels 15R, 15L via the brake member support shaft 42 (see Figure 6(C)), i.e., in a braking released state.

[0070] The brake release pedal 48 is supported via a pedal support shaft 47 between a pair of left and right pedal support parts 46R, 46L that are erected at a fixed width on the rear surface of the center of the rear part of the cargo bed 11 in correspondence with the lever hook part 44 of the foot lever 43. The brake release pedal 48 has an opening that resembles an alligator mouth when viewed from the side, and is provided so that it can rotate up and down around the pedal support shaft 47 that passes through the back side of the opening, with the opening facing the rear of the cargo bed 11.

[0071] The brake release pedal 48 has the aforementioned first groove 48a formed in the left-right direction on the lower jaw side of the alligator opening, and also has the aforementioned second groove 48b formed in the left-right direction on the back side of the opening. The head of the brake release pedal 48 on the opening side serves as the pedal depression part 48c.

[0072] A pedal lifting spring 49 is provided between the left and right sides of the lower jaw of the brake release pedal 48 and the back surface of the cargo bed 11, and a spring force is applied to the brake release pedal 48 to rotate the brake release pedal 48 upward.

[0073] In addition, spring forces tending to rotate upward are applied to the foot lever 43 by lever pull-up springs 45R, 45L, and to the brake release pedal 48 by pedal pull-up spring 49. However, the lever hook portion 44 of the foot lever 43, which is located further back than the brake release pedal 48 (closer to the front of the cargo bed 11), is positioned so as to straddle the opening of the brake release pedal 48 from below. Therefore, in either the braked state of the rear wheels 15R, 15L in which the lever hook portion 44 is engaged in the first groove 48a of the brake release pedal 48 (see Figure 6(A)), or the brake-released state of the rear wheels 15R, 15L in which the lever hook portion 44 is engaged in the second groove 48b of the brake release pedal 48 (see Figure 6(D)), the brake release pedal 48 will not rotate upward beyond the horizontal of its pedal depression portion 48c.

[0074] Next, the operation of the hand truck 1 will be described.

[0075] (Operation of handcart 1) Assume that a load is loaded onto a hand truck 1 that is stopped, and the hand truck 1 is operated by human power to move forward or backward.

[0076] FIG. 6 is a diagram illustrating the operation of releasing the braked state of the rear wheels 15R, 15L by the brake release pedal 48 of the wheel braking mechanism, as viewed from the right side of the dolly 1.

[0077] Figure 7 is an enlarged view showing the relationship between the brake release pedal 48 and the lever hook portion 44 of the foot lever 43, which corresponds to the movement of releasing the braked state of the rear wheels 15R, 15L in Figure 6, with (A1), (B1), and (C1) being right side views, and (A2), (B2), and (C2) being rear views.

[0078] First, as shown in Figures 6(A) and 7(A), when the lever engaging portion 44 of the foot lever 43 is straddling the first groove 48a of the brake release pedal 48, the wheel braking members 40R, 40L are pressed against the outer peripheral surfaces of the rear wheels 15R, 15L via the braking member support shaft 42, the rear wheels 15R, 15L are braked, and the trolley 1 is stopped.

[0079] When moving the trolley 1, as shown by arrows i1 to j1 in Figures 6(B) and 7(B), the pedal depression portion 48c of the brake release pedal 48 is depressed downward, and the brake release pedal 48 is rotated downward against the spring force of the pedal lifting spring 49, and the lever hook portion 44 of the foot lever 43 moves out of the first groove 48a of the brake release pedal 48 in accordance with the spring force of the lever lifting springs 45R, 45L and is positioned at the entrance of the second groove 48b.

[0080] 6(C) and 7(C), when the brake release pedal 48 is released from depression, the brake release pedal 48 is rotated upward (returned to its original horizontal position) in accordance with the spring force of the pedal pull-up spring 49, and the lever hook portion 44 of the foot lever 43 is pulled up by the spring force of the lever pull-up springs 45R and 45L, engaging with the second groove 48b of the brake release pedal 48. Then, as shown by arrow j2 in FIG. 6(C), the wheel braking members 40R and 40L are disengaged from the outer peripheral surfaces of the rear wheels 15R and 15L via the braking member support shaft 42, and the braking of the rear wheels 15R and 15L is released.

[0081] As shown by arrows k1 to k2 in Figure 6(C), when the lock release levers 24R, 24L provided on both ends of the handlebar 18H are pulled rearward, the handlebar lock bar 21 is pushed downward via the lock release links 26R, 26L, and is released from the neutral recess (lock position) 22N of the handlebar movable hole 22.

[0082] <Forward> Here, by gripping the handle bar 18H together with the clutch bars 33a, 33b, as shown in Figure 5, the clutch plates 32R, 32L are pressed against the ratchet type first gears 28R, 28L, and when the handle bar 18H begins to be pushed forward, as shown in Figures 3(B) and 4(B), the movable handle 18 tilts forward within the range from the neutral recess (lock position) 22N to the forward recess (forward position) 22F of the handle movable hole 22, with the handle support shafts 19R, 19L at its lower end as the fulcrum, and at the same time, a forward rotational force f1 corresponding to the tilt of the movable handle 18 is transmitted to the ratchet type first gears 28R, 28L via the clutch plates 32R, 32L.

[0083] Then, a forward rotational force f4 is transmitted to the rear wheels 15R, 15L from the ratchet-type first gears 28R, 28L via the second gears 30R, 30L and the third gears 31R, 31L, causing the rear wheels 15R, 15L to rotate forward FR, and the bogie 1 begins to move in the forward direction F.

[0084] After this, as the trolley 1 gains a certain amount of momentum in the forward direction F, the required forward pushing force on the movable handle 18 weakens, and the movable handle 18, together with the handle lock bar 21, is pulled back to the neutral position by the spring force B of the forward retraction spring 23F, and the handle lock bar 21 re-fits into the neutral recess (lock position) 22N of the handle movable hole 22, returning to a fixed state.

[0085] Then, as shown in Figure 6(D), with the movable handle 18 fixed in the neutral position, the carriage 1 can be continuously moved forward F by continuing to push the movable handle 18 forward with a light force.

[0086] In this way, by leaning forward in response to pushing out the movable handle 18 while firmly gripping it with both hands, an assisting force for starting to move the cart 1 forward can be obtained, and the cart 1 can be started easily and stably to move forward F even when it is loaded with heavy luggage.

[0087] <Reverse> Furthermore, by gripping the handle bar 18H together with the clutch bars 33a, 33b, as shown in Figure 5, the clutch plates 32R, 32L are pressed against the ratchet type first gears 28R, 28L, and when the handle bar 18H begins to be pulled rearward, as shown in Figures 3(C) and 4(C), the movable handle 18 tilts rearward within the range from the neutral recess (lock position) 22N to the rear recess (reverse position) 22B of the handle movable hole 22, with the handle support shafts 19R, 19L at its lower end as the fulcrum, and at the same time, a rearward rotational force b1 corresponding to the tilting of the movable handle 18 is transmitted to the ratchet type first gears 28R, 28L via the clutch plates 32R, 32L.

[0088] Then, a backward rotational force b4 is transmitted to the rear wheels 15R, 15L from the ratchet-type first gears 28R, 28L via the second gears 30R, 30L and the third gears 31R, 31L, causing the rear wheels 15R, 15L to rotate backward BR, and the bogie 1 begins to move in the backward direction B.

[0089] After this, as the trolley 1 gains a certain amount of momentum in the reverse direction B, the required backward pulling force on the movable handle 18 weakens, and the movable handle 18, together with the handle lock bar 21, is pulled back to the neutral position by the spring force F of the reverse retraction spring 23B, and the handle lock bar 21 re-fits into the neutral recess (lock position) 22N of the handle movable hole 22, returning to a fixed state.

[0090] Then, as shown in FIG. 6(D), by continuing to pull the movable handle 18 backward while the movable handle 18 is fixed in the neutral position, the carriage 1 can be made to continue moving backward B.

[0091] In this way, by tilting the cart 1 backward in response to pulling in the movable handle 18 while firmly gripping it with both hands, an assist force for starting to move the cart 1 backward can be obtained, and the cart 1 can be easily and stably started to move backward B even when it is loaded with heavy luggage.

[0092] <stop> When braking the cart 1 to stop it after moving it forward or backward, the foot levers 43 located horizontally on both the left and right sides of the brake release pedal 48 are depressed in the state shown in Figure 6(D).

[0093] As a result, the lever hook portion 44 of the foot lever 43 moves out of the second groove 48b of the brake release pedal 48 and is positioned at the entrance of the first groove 48a, accompanied by a downward rotation of the brake release pedal 48 (see Figures 6(B) and 7(B)).

[0094] Then, when the foot lever 43 is released from depression, the brake release pedal 48 rotates upward and returns, and the lever hook portion 44 of the foot lever 43, which was located at the entrance of the first groove 48a of the brake release pedal 48, hooks onto the first groove 48a and is pulled up, as shown in Figures 6(A) and 7(A).

[0095] As a result, the wheel braking members 40R, 40L are pressed against the outer circumferential surfaces of the rear wheels 15R, 15L via the braking member support shafts 42, the rear wheels 15R, 15L are braked, and the carriage 1 is stopped.

[0096] <Assist force setting> Figure 8 is a diagram explaining the gear ratios of the ratchet-type first gears 28R, 28L, second gears 30R, 30L, and third gears 31R, 31L, which transmit the operating force for tilting the movable handle 18 as a rotational force of the rear wheels 15R, 15L.

[0097] If the number of teeth of the ratchet type first gears 28R and 28L is Z1, the number of teeth of the second gears 30R and 30L is Z2, and the number of teeth of the third gears 31R and 31L is Z3, then: Gear ratio = (Z2 / Z1) x (Z3 / Z2) = Z3 / Z1 By increasing the gear ratio, the rotational force (assist force) transmitted to the rear wheels 15R, 15L is increased, and by decreasing the gear ratio, the rotational force (assist force) transmitted to the rear wheels 15R, 15L is decreased.

[0098] (Summary of the embodiment) According to the hand truck 1 of this embodiment, when the handle bar 18H of the movable handle 18 is gripped together with the clutch bars 33a, 33b and pushed forward (or pulled backward), the movable handle 18 tilts forward (or backward) around the handle support shafts 19R, 19L at the lower ends of the support posts 18R, 18L as fulcrums. The operating force associated with tilting the movable handle 18 is transmitted as a forward (or backward) rotational force to the ratchet-type first gears 28R, 28L via the clutch plates 32R, 32L coaxial with the handle support shafts 19R, 19L, and causes the rear wheels 15R, 15L to rotate forward FR (or backward BR) via the second gears 30R, 30L and the third gears 31R, 31L. The truck 1 is then started in the forward direction F (or backward direction B).

[0099] The forward rotation FR (or backward direction B) of the rear wheels 15R, 15L caused by the carriage 1 continuing to move forward (or backward) after starting is permitted by the forward (or backward) idle rotation of the ratchet-type first gears 28R, 28L.

[0100] Then, when the required forward (or backward) pushing (or pulling) force on the movable handle 18 weakens, the movable handle 18 is pulled back to the neutral position together with the handle lock bar 21 by the forward retraction spring 23F (or reverse retraction spring 23B), and the trolley 1 continues to move forward (or backward).

[0101] Therefore, not only is there no need for electric assistance, but the cart can be started and moved easily and stably without the need to operate a lever separate from the handle or to step on a pedal.

[0102] It goes without saying that the mechanical structures constituting the handle lock mechanism, handle operation force transmission mechanism, wheel braking mechanism, etc. of the embodiments are not limited, and it is sufficient if the functions obtained by the operation of each mechanism are similar.

[0103] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0104] 1...hand truck, 11...loading platform, 12R, 12L...front wheels, 15R, 15L...rear wheels, 18...movable handle, 18H...handle bar, 19R, 19L...handle support shaft, 20R1, 20R2, 20L1, 20L2...handle support plate, 21...handle lock bar, 22...handle movable hole, 23F...forward retraction spring, 23B...reverse retraction spring, 24R, 24L...lock release lever bar, 26R, 26L...unlock link, 28R, 28L...ratchet type first gear, 28S...ratchet switch, 30R, 30L...second gear, 31R, 31L...third gear, 32R, 32L...clutch plate, 33a, 33b...clutch bar, 40R, 40L...wheel braking member, 42...braking member support shaft, 43...foot lever, 44...lever hook portion, 48...brake release pedal.

Claims

1. The loading platform and Wheels supported on the rear surface of the loading platform so as to be rotatable in the front-rear direction of the loading platform; a handle that is provided upright on the loading platform and supported so as to be tiltable forward or backward with a lower end thereof as a fulcrum; a handle operation force transmission mechanism that is provided between a lower end of the handle and the wheels and that transmits a force that rotates the lower end of the handle as the handle is tilted forward or backward as a force that rotates the wheels forward or backward, The handle operation force transmission mechanism includes: a handle support shaft that supports a lower end of the handle on the carrier; a ratchet gear that is supported coaxially with the handle support shaft and that can rotate only forward when the handle is tilted forward and can rotate only backward when the handle is tilted backward; a clutch plate that is supported coaxially with the handle support shaft, that rotates forward in conjunction with the rotation of the lower end when the handle is tilted forward, and that rotates rearward in conjunction with the rotation of the lower end when the handle is tilted rearward, and that transmits the forward rotation or the rearward rotation by pressing against the ratchet gear; a wheel gear supported coaxially with the wheel support shaft and rotating together with the wheel; and at least one intermediate gear meshed between the ratchet gear and the wheel gear. Hand cart.

2. The handle operation force transmission mechanism includes: a clutch bar provided so as to protrude and be embedded in a handlebar that is a portion of the handle that is gripped by a user; The clutch plate is pressed against the ratchet gear in response to the movement of the clutch bar sinking into the handlebar. The hand truck according to claim 1.

3. a handle lock mechanism that supports the handle at a position where it can be tilted forward or backward in response to a user operation and at a neutral position; The hand truck according to claim 1 or 2.

4. The handle lock mechanism is a handle lock bar that is slidable in the up and down direction and is provided on the support of the handle in a horizontal direction perpendicular to the front-rear direction of the loading platform; a handle support plate that is erected on the loading platform along at least one of the left and right sides of the support pillar of the handle, and that has a handle movable hole formed therein, the handle movable hole having a neutral recess into which the handle lock bar fits when the handle is in a neutral position, a front recess that is positioned within a range in which the handle can be tilted forward, and a rear recess that is positioned within a range in which the handle can be tilted backward; a plurality of return springs provided on the handle support plate, the return springs acting to return the handle lock bar toward the neutral recess when the handle lock bar is positioned in the front recess or the rear recess; an unlocking lever provided on the handle and configured to operate the handle lock bar to release it from the neutral recess in response to a user operation; The hand truck according to claim 3, comprising:

5. a wheel braking mechanism provided at a rear portion of the loading platform and configured to brake and release the wheels in response to a user's depression operation; A hand truck according to any one of claims 1 to 4.

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