JP7655558B2 - Transport cart - Google Patents

Description

The present invention relates to a transport cart.

Transport carts are used to transport items at work sites and the like. The transport cart has casters attached to the four corners of the underside of the cart body. Patent Document 1 discloses a transport cart in which the caster mounting plate is riveted to the cart body, making it easy to attach the casters.

JP 2011-046379 A

Such transport carts are required to be able to run and turn smoothly in order to reduce the labor required by workers.
The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a transport cart with improved running performance and turning performance.

The transport cart of the present invention is a transport cart comprising a cart body, first casters arranged at four corners of the cart body, and two second casters arranged in the center of each pair of adjacent casters among the casters arranged at the four corners, wherein the first casters are each rotatable about a swivel axis, have two wheels, a support portion that supports the two wheels independently rotatably, and a brake pedal, and are configured with a braking function, and the second casters are each rotatable about a swivel axis, have two wheels, and a support portion that supports the two wheels independently rotatably, and are configured without a braking function. wherein each of the two wheels of the first caster and each of the two wheels of the second caster are the same size, and when viewed from the bottom side in a state in which the traveling direction of the transport cart is along the longitudinal direction, the wheel of the two wheels of the first caster located on the outer side of the transport cart does not overlap with an extension line obtained by extending the inner outline of the outline of the wheel of the two wheels of the second caster located on the outer side of the transport cart along the longitudinal direction, but is positioned inside the extension line , and an extension area obtained by extending the outline of the brake pedal along the longitudinal direction overlaps with the wheel of the two wheels of the second caster located on the inner side of the transport cart .

The present invention can improve the travelling and turning performance of the transport cart.

FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG.

The transport cart according to this embodiment will be described with reference to the drawings.
Fig. 1 is a plan view of the transport cart 10. Fig. 2 is a bottom view of the transport cart 10. Fig. 3 is a side view of the transport cart 10. Fig. 4 is a view of the transport cart 10 from the rear. Fig. 5 is a view of the transport cart 10 from the front. For convenience, in the following drawings, arrow Fr indicates the front side, arrow Rr indicates the rear side, arrow R indicates the right side, and arrow L indicates the left side. However, the transport cart 10 can travel in any direction, forward/backward, left/right, on the traveling surface.

The transport cart 10 comprises a cart main body 20 and a running section 30.
The bogie body 20 is configured by connecting a plurality of frame parts and has a rectangular shape that is longer in the front-rear direction than in the left-right direction when viewed from above, and has a pair of long sides and a pair of short sides. As shown in Figures 1 and 2, the bogie body 20 has a front frame part 21a, a rear frame part 21b, a right frame part 21c, a left frame part 21d, a corner member 22, reinforcing frame parts (reinforcing parts) 25a, 25b, 25c, etc.

The front frame portion 21a, the rear frame portion 21b, the right frame portion 21c, and the left frame portion 21d can be, for example, hollow angular pipes made of an aluminum alloy. The corner member 22 is made of an aluminum alloy and formed, for example, by extrusion molding. The corner member 22 has an insertion hole 23 that opens upward and a stopper portion 24 that closes the downward side. A hand push member can be inserted into the insertion hole 23 of the corner member 22. The lower end of the hand push member inserted into the insertion hole 23 is supported by the stopper portion 24. The hand push member can be, for example, a straight pipe with a circular cross section made of iron or an aluminum alloy, a so-called single pipe.

The front frame portion 21a, the rear frame portion 21b, the right frame portion 21c, and the left frame portion 21d are joined at four corners by corner members 22 to form a rectangular frame on all four sides. The inside of the frame is reinforced by a plurality of reinforcing frame portions 25a, 25b, and 25c that are butted together in the front-rear and left-right directions and joined by screws, rivets, welding, or the like. The reinforcing frame portions 25a, 25b, and 25c may be, for example, hollow pipes made of an aluminum alloy or plates with uneven cross sections. Here, a plurality of rectangular spaces 26 are formed that are divided into three rows in the front-rear direction and four rows in the left-right direction when viewed from above by joining twelve reinforcing frame portions 25c that are short in the left-right direction to two reinforcing frame portions 25a and 25b that are long in the front-rear direction.
In addition, in the cart body 20, a loading plate 27 is attached to the upper part of the spaces 26 that are not closed by the mounting plates 32A and 32B described later among the plurality of spaces 26. The loading plate 27 is a flat plate on which transported objects are placed. The loading plate 27 is connected to each frame portion and each reinforcing frame portion by rivets or screws.

The running section 30 runs on the running surface while supporting the load of the cart body 20 and the transported object. The running section 30 has a number of casters 31A, 31B. As shown in FIG. 2, the running section 30 has six casters: four casters 31A located at the four corners of the cart body 20, and two casters 31B located in the center in the front-to-rear direction and spaced apart on the left and right. The casters 31A, 31B are attached to the cart body 20 via mounting plates 32A, 32B connected to each frame section and each reinforcing claim section in a manner that blocks the space 26 from below.

Here, the casters 31A disposed at the four corners are braked casters that can be braked or released in response to a user's operation, while the caster 31B disposed in the center is a non-brake caster.
Each of the casters 31A and 31B of this embodiment has two wheels 33a and 33b. The two wheels 33a and 33b are of the same size and are supported in parallel so that they can rotate independently. That is, the wheels 33a and 33b can be rotated at different rotation speeds, and the wheel 33a can be rotated to one side and the wheel 33b can be rotated to the other side at the same time. A gap is formed between the wheels 33a and 33b. The gap is narrower than the width dimension of each wheel, and is narrower than 1/2 the width dimension of each wheel, and the wheels 33a and 33b are close to each other.

Here, a comparison is made between a caster of the same size and with the same load capacity, which has only one wheel, and a caster of the present embodiment, which has two wheels 33a and 33b.
In the case where the transport cart 10 has the wheels 33a and 33b, narrower wheels can be used than in the case where only one wheel is used. Therefore, in the case where the transport cart 10 has the two wheels 33a and 33b, the ground contact area of the wheels 33a and 33b can be made smaller, so that friction can be reduced and the travelling performance of the transport cart 10 can be improved.
In addition, when the transport cart 10 travels around a curve, one of the wheels 33a, 33b can function as an outer wheel and the other as an inner wheel. Therefore, the transport cart 10 can travel around a curve with the rotation speed of the outer wheel increased and the rotation speed of the inner wheel decreased, allowing the transport cart 10 to travel smoothly.

When the transport cart 10 is turned on the spot, the caster farthest from the turning center among the six casters 31A, 31B turns to increase the rotation speed of the outer wheel and decrease the rotation speed of the inner wheel, as in the case of traveling around a curve. On the other hand, the caster closer to the turning center among the six casters 31A, 31B can turn with reduced friction by rotating the wheel 33a to one side and the wheel 33b to the other side, thereby improving the turning ability of the transport cart 10. In narrow work sites, the transport cart 10 is often turned on the spot, and in this case, the central caster 31B is often close to the turning center, and by having the central caster 31B have two wheels 33a, 33b, the turning ability can be further improved.

As shown in FIG. 2, when straight lines L1 and L2 are drawn along the front-rear direction, the outer wheel 33a of the front caster 31A, the inner wheel 33b of the central caster 31B, and the outer wheel 33a of the rear caster 31B overlap on the straight lines L1 and L2. That is, when viewed from the direction of travel, the wheels 33a of the caster 31A and the wheels 33b of the caster 31B are arranged in a position where they overlap. Therefore, the left-right distance between the two central casters 31B is wider than the left-right distance between the four casters 31A, and the transport cart 10 can run stably. On the other hand, by not widening the left-right distance between the two central casters 31B too much, it is possible to prevent the central caster 31B from colliding with an obstacle.

On the other hand, since the casters 31A, 31B have two wheels 33a, 33b, there is a risk that foreign objects may get caught between the wheels 33a and 33b, which may reduce the travelling performance of the transport cart 10 or reduce the effectiveness of the brakes.
The casters 31A and 31B of this embodiment have a function of removing foreign objects caught between the wheels 33a and 33b. The configuration of the caster 31A will be specifically described below. Note that the caster 31B is a configuration in which the brake function is omitted from the caster 31A, and a specific description thereof will be omitted.

FIG. 6 is an exploded perspective view of the caster 31A.
The caster 31A has two wheels 33a, 33b, a support portion 34, a brake pedal 39, a removal member 43, and the like.
The wheels 33a, 33b have the same configuration and dimensions, and each have a wheel portion with a built-in bearing and a tire portion fitted onto the outer periphery of the wheel portion.

The support portion 34 supports the two wheels 33a, 33b via an axle 35 so as to be rotatable independently of each other. The support portion 34 has a fork member 36 and a pedal holding member 37.
The fork member 36 is formed, for example, by press-molding a steel plate. The fork member 36 is integrally formed with a pair of support parts 36a located on both sides of the two parallel wheels 33a, 33b, and a circular top plate 36b that connects the pair of support parts 36a above the wheels 33a, 33b. Each of the pair of support parts 36a is formed with an axle hole 36c through which the axle 35 is inserted, and an axle hole 36d for supporting the pedal holding member 37. The wheels 33a, 33b are positioned between the pair of support parts 36a, the axle 35 is inserted through the axle hole 36c and the wheels 33a, 33b, and both ends of the axle 35 are supported by the pair of support parts 36a, so that the fork member 36 supports the wheels 33a, 33b so that they can rotate independently. In the fork member 36, the wheels 33a, 33b are positioned between the pair of shaft supports 36a, thereby making it possible to prevent the wheels 33a, 33b from colliding with an obstacle.

The pedal holding member 37 is formed, for example, by press-molding a steel plate. The pedal holding member 37 is integrally formed with a pair of side walls 37a located on both sides of the two wheels 33a, 33b, and a connecting plate 37b connecting the pair of side walls 37a at the upper side. The pair of side walls 37a are formed by extending a bifurcated first support portion 37c and a bifurcated second support portion 37d from the connecting plate 37b in different directions. An axle hole 37e is formed at the tip side of the first support portion 37c, which communicates with the axle hole 36c of the fork member 36 and through which the axle 35 is inserted. On the other hand, an axle hole 37f is formed at the tip side of the second support portion 37d, which communicates with the axle hole 36d of the fork member 36 and through which the shaft member 38 is inserted.
A support hole 37g for pivotably supporting the brake pedal 39 is formed in an upper portion of the side wall 37a in a position close to the connecting plate 37b. A long hole 37h that is long in the approximately front-rear direction is formed below the support hole 37g in the side wall 37a.
When the pedal holding member 37 is supported by the fork member 36 via the axle 35 and the shaft member 38, the connecting plate 37b is inclined downward as it approaches the rear.

The pedal holding member 37 also supports a leaf spring 40 as a biasing member via an axle member 38 that passes through the axle hole 37f. The leaf spring 40 is formed, for example, by press-molding a stainless steel plate. The leaf spring 40 has a support hole 40a through which the axle member 38 passes, and one end 40b and the other end 40c that extend in different directions from the support hole 40a. A protrusion 40d, part of which protrudes upward, is formed on the tip side of the other end 40c along the plate width direction. A groove 40e is formed in the center of the axial direction of the support hole 40a.

The brake pedal 39 is formed, for example, by press forming a steel plate. The brake pedal 39 has a pedal body 39a and an operating piece 39b as an operating portion that extends integrally from the pedal body 39a.
The pedal body 39a is integrally formed with a pair of side walls 39c located on both sides of the wheels 33a, 33b, and a connecting plate 39d connecting the pair of side walls 39c at the upper part. When the caster 31A is viewed from the rear side, the brake pedal 39 is disposed at a position overlapping the wheels 33a, 33b. The distance between the pair of side walls 39c is formed narrower than the distance between the pair of side walls 39a of the pedal holding member 37. Therefore, the brake pedal 39 can be positioned in the pedal holding member 37 with the connecting plate 39d overlapping the connecting plate 37b of the pedal holding member 37. In addition, a swing hole 39e is formed in the front and upper part of the side wall 39c, which communicates with the support hole 37g of the pedal holding member 37 and through which the shaft member 41 is inserted. By inserting the shaft member 41 into the support hole 37g and the swing hole 39e, the pedal holding member 37 supports the brake pedal 39 so as to be swingable around the shaft member 41. Further, below the swing hole 39e of the side wall 39c, a shaft hole 39f is formed which communicates with the long hole 37h of the pedal holding member 37 and through which the shaft member 42 is inserted. When the brake pedal 39 swings, the shaft member 42 also moves in conjunction with the long hole 37h of the pedal holding member 37. The shaft member 42 is always in contact with the upper surface of the other end 40c of the leaf spring 40.
The operation piece 39b is generally plate-shaped and is operated by the user's foot or the like to swing the brake pedal 39 up and down. The operation piece 39b is formed to extend obliquely from the rear part of the connecting plate 39d of the pedal body 39a. The operation piece 39b is formed in a rectangular shape with a plate width substantially the same as that of the connecting plate 39d.

The removal member 43 removes foreign matter caught between the wheels 33a and 33b. The removal member 43 is formed, for example, by press-molding a steel plate. The removal member 43 is plate-shaped or rod-shaped, thinner than the width dimension of the wheels 33a and 33b, and is disposed in the gap between the wheels 33a and 33b. The removal member 43 has a hole 43b through which the axle 35 is inserted at one end 43a, and a hole 43d through which the shaft member 38 is inserted at the other end 43c. In addition, the edge surface of the removal member 43 formed between the end 43a on one side and the end 43c on the other side functions as a removal portion 43e that abuts against foreign matter. The axle 35 is inserted into the hole 43b, and the shaft member 38 is inserted into the hole 43d, so that the removal member 43 is supported in a state of being spanned between the axle 35 and the shaft member 38. At this time, the other end 43 c of the removal member 43 is disposed in the groove 40 e of the leaf spring 40 .

Additionally, the top plate 36b of the fork member 36 is sandwiched from above and below by an upper plate member 45 and a lower plate member 46. Fig. 7 is a cross-sectional view of the caster 31A. As shown in Fig. 7, an insertion hole 36e is formed in the center of the top plate 36b coaxially with the pivot axis C of the caster 31A, and an annular accommodation groove is formed on the top surface of the top plate 36b around the pivot axis C so that a plurality of bearings 47 can be stably arranged on the top surface, and a plurality of bearings 48 can be stably arranged on the bottom surface.
The upper tray member 45 is formed in a circular shape larger than the top plate 36b, and has an insertion hole 45a formed in the center coaxially with the pivot axis C. In addition, the upper tray member 45 has an annular accommodation groove formed on the lower surface thereof for stably disposing the bearing 47.
The lower tray member 46 is formed in a circular shape smaller than the top plate 36b, and has an insertion hole 46a formed in the center coaxially with the pivot axis C. In addition, the lower tray member 46 has an annular accommodation groove formed on the upper surface thereof for stably disposing a bearing 48.
Here, the upper tray member 45 and the lower tray member 46 are integrally joined so as not to rotate relatively near the insertion holes 45a and 46a. Therefore, the top plate 36b, i.e., the fork member 36, can rotate about the pivot axis C relative to the upper tray member 45 and the lower tray member 46 via the bearings 47 and 48.

The caster 31A is configured as described above, by connecting the insertion holes 45a of the upper plate member 45, the insertion holes 36e of the top plate 36b, the insertion holes 46a of the lower plate member 46, and the insertion holes (not shown) of the mounting plate 32A, and then inserting bolts through them and fastening them with nuts, thereby attaching the caster 31A to the mounting plate 32A.
On the other hand, the caster 31B is configured by omitting the fork member 36, the brake pedal 39, the leaf spring 40, the shaft member 41 and the shaft member 42 of the caster 31A. Therefore, in the caster 31B, similarly to the caster 31A, the removal member 43 is supported in a state in which it is suspended between the axle 35 and the shaft member 38. The caster 31B configured in this manner is attached to the mounting plate 32B.
Finally, the mounting plates 32A and 32B are attached to the carriage body 20 at predetermined positions with rivets or screws so as to close the space 26, thereby completing the transport carriage 10.

Here, the operation of each member of the caster 31A from a brake-released state to a brake-applied state will be described with reference to FIG.
7, when the brake is released, the brake pedal 39 is in an elevated position centered on the shaft member 41. Here, one end 40b of the leaf spring 40 is in contact with the top plate 36b, and the other end 40c is in contact only with the shaft member 42 due to the biasing force of the leaf spring 40 itself. In other words, since the wheels 33a, 33b are not in contact with any member, the wheels 33a, 33b can rotate freely, and the brake is released.

On the other hand, when the user operates the brake pedal 39 by depressing the operating piece 39b downward with his/her foot, the brake pedal 39 swings downward about the shaft member 41 against the bias of the leaf spring 40 and the frictional forces between the respective members. At this time, the shaft member 42 moves within the long hole 37h toward the protruding portion 40d of the leaf spring 40 in conjunction with the movement of the brake pedal 39.
As the shaft member 42 moves within the long hole 37h to the extent that it gets over the apex of the protruding portion 40d of the leaf spring 40, the leaf spring 40 is pushed toward the wheels 33a, 33b by the shaft member 42. Therefore, the lower surface of the leaf spring 40 firmly presses against the outer circumferential surfaces of the wheels 33a, 33b, so that the wheels 33a, 33b cannot rotate and a brake is applied.

Next, the action of the removal member 43 when removing a foreign object caught between the wheels 33a and 33b of the caster 31A will be described. As shown in FIG. 7, assume that a foreign object, such as debris D of construction materials, is left on the running surface and becomes caught in the gap between the wheels 33a and 33b while the transport cart 10 is running. If the debris D remains caught, the wheels 33a and 33b will rotate together through the debris D, resulting in reduced running performance. Also, if the leaf spring 40 presses against the debris D when the brakes are applied, the wheels 33a and 33b cannot be pressed sufficiently, resulting in reduced braking effectiveness.

FIG. 8 is a cross-sectional view showing a state when the removal member 43 removes the fragments D.
The debris D caught between the wheels 33a and 33b rotates toward the removal member 43 as the wheels 33a and 33b rotate. The debris D hits the removal portion 43e of the removal member 43 and is released from between the wheels 33a and 33b. At this time, the removal portion 43e of the removal member 43 is inclined so that the upper portion is inclined with respect to the vertical line, in other words, the higher it is, the more forward it is. Therefore, the debris D is scraped out toward the outer periphery of the wheels 33a and 33b and is discharged to the outside of the caster 31A.

Further, the removal member 43 is located between the wheels 33a and 33b, and extends outward from the axle 35. Therefore, even if the fragment D is caught in a position close to the axle 35, the fragment D can be abutted against the removal member 43, and the trapped fragment D can be removed.
Furthermore, the removal member 43 extends from the shaft member 38 supported by the fork member 36 of the support portion 34 toward between the wheels 33a and 33b. Therefore, even if the fragment D is caught in a position close to the outer circumferential surface, the fragment D can be abutted against the removal member 43, and the caught fragment D can be removed.
In addition, the removal member 43 is positioned between the wheels 33a and 33b, thereby preventing the wheels 33a and 33b from coming into direct contact with each other. In addition, the removal member 43 can be manufactured inexpensively because it is plate-shaped or rod-shaped, and can maintain its strength because both ends are supported by the axle 35 and the shaft member 38.
Although the caster 31A has been described here, the removal member 43 can also remove the debris D caught between the wheels 33a and 33b of the caster 31B in a similar manner.

Although the present invention has been described above with reference to the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment, and modifications and the like are possible within the scope of the present invention.
In the above embodiment, the case where six casters 31A, 31B are arranged by forming a pair of adjacent two casters 31A among the casters 31A arranged at the four corners, and arranging a caster 31B at the center of each pair of casters 31A in each pair has been described, but this is not limited to this case. The number of casters 31A, 31B can be freely changed depending on the purpose of the transport cart 10. For example, the casters 31A may be arranged only at the four corners of the cart body 20, or six or more casters may be arranged. When six or more casters are arranged, it is preferable that each caster has two wheels 33a, 33b and a removal member 43.

In the above embodiment, the caster 31A has been described as having the support portion 34 formed by the fork member 36 and the pedal holding member 37. By forming them as separate bodies in this manner, the fork member 36 of the casters 31A and 31B can be a common member. However, this is not limited to this case, and the fork member 36 and the pedal holding member 37 of the caster 31A may be integral with each other.
In the above embodiment, the transport cart 10 has the placement plate 27, but this is not limited to the above case, and the placement plate 27 may be omitted.

10: Transport cart 20: Cart body 31A, 31B: Casters 32A, 32B: Mounting plate 33a, 33b: Wheels 34: Support 35: Axle 43: Removal member

Claims (4)

A transport cart including a cart body, first casters arranged at four corners of the cart body, and two second casters arranged in the middle of each pair of adjacent two casters among the casters arranged at the four corners,
The first casters are each rotatable about a pivot axis,
Two wheels and
A support portion that supports the two wheels so as to be rotatable independently of each other;
and a brake pedal, and configured to have a braking function,
The second casters are each rotatable about a pivot axis,
Two wheels and
and a support portion for supporting the two wheels so as to be rotatable independently of each other, and the brake function is omitted.
Each wheel of the two wheels of the first caster and each wheel of the two wheels of the second caster are the same size;
A transport cart characterized in that, when viewed from the bottom side with the direction of travel of the transport cart along the longitudinal direction, the wheel of the two wheels of the first caster located on the outer side of the transport cart does not overlap with an extension line of the inner outline of the outer edge of the wheel of the two wheels of the second caster located on the outer side of the transport cart along the longitudinal direction, but is positioned inside the extension line, and an extension area of the outline of the brake pedal extended along the longitudinal direction overlaps with the wheel of the two wheels of the second caster located on the inner side of the transport cart . A transport cart including a cart body, first casters arranged at four corners of the cart body, and two second casters arranged in the middle of each pair of adjacent two casters among the casters arranged at the four corners,
The first casters are each rotatable about a pivot axis,
Two wheels and
A support portion that supports the two wheels so as to be rotatable independently of each other;
and a brake pedal, and configured to have a braking function,
The second casters are each rotatable about a pivot axis,
Two wheels and
and a support portion for supporting the two wheels so as to be rotatable independently of each other, and the brake function is omitted.
Each wheel of the two wheels of the first caster and each wheel of the two wheels of the second caster are the same size;
A transport cart characterized in that, when viewed from the bottom side with the direction of travel of the transport cart along the longitudinal direction, the wheel of the two wheels of the first caster located on the inside of the transport cart does not overlap with an extension line of the inner outline of the wheel of the two wheels of the second caster located on the inside of the transport cart, which is an extension line of the inner outline along the longitudinal direction, but is positioned inside the extension line, and an extension area of the outline of the brake pedal extended along the longitudinal direction overlaps with the wheel of the two wheels of the second caster located on the inside of the transport cart . A transport cart including a cart body, first casters arranged at four corners of the cart body, and two second casters arranged in the middle of each pair of adjacent two casters among the casters arranged at the four corners,
The first casters are each rotatable about a pivot axis,
Two wheels and
A support portion that supports the two wheels so as to be rotatable independently of each other;
and a brake pedal, and configured to have a braking function,
The second casters are each rotatable about a pivot axis,
Two wheels and
and a support portion for supporting the two wheels so as to be rotatable independently of each other, and the brake function is omitted.
Each wheel of the two wheels of the first caster and each wheel of the two wheels of the second caster are the same size;
A transport cart characterized in that, when viewed from the bottom side with the direction of travel of the transport cart along the longitudinal direction, an extension line of the gap between the two wheels of the first caster extending along the longitudinal direction is located more inward than the wheel of the two wheels of the second caster that is located on the inside of the transport cart , and an extension area of the outline of the brake pedal extending along the longitudinal direction overlaps with the wheel of the two wheels of the second caster that is located on the inside of the transport cart . A transport cart including a cart body, first casters arranged at four corners of the cart body, and two second casters arranged in the middle of each pair of adjacent two casters among the casters arranged at the four corners,
The first casters are each rotatable about a pivot axis,
Two wheels and
A support portion that supports the two wheels so as to be rotatable independently of each other;
and a brake pedal, and configured to have a braking function,
The second casters are each rotatable about a pivot axis,
Two wheels and
and a support portion for supporting the two wheels so as to be rotatable independently of each other, and the brake function is omitted.
Each wheel of the two wheels of the first caster and each wheel of the two wheels of the second caster are the same size;
A transport cart characterized in that, when viewed from the bottom side with the direction of travel of the transport cart along the longitudinal direction, an extension line of the gap between the two wheels of the second caster extending along the longitudinal direction is located outside the wheel of the two wheels of the first caster that is located on the outside of the transport cart , and an extension area of the outline of the brake pedal extending along the longitudinal direction overlaps with the wheel of the two wheels of the second caster that is located on the inside of the transport cart .

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