JP6228020B2 - Transport cart and method for manufacturing the same - Google Patents

Description

  The present invention relates to a transport cart, and more particularly to a transport cart capable of traveling in an arbitrary direction on a travel surface by an operator's hand pushing operation.

As for trolleys used in logistics, there has been a strong demand for weight reduction from the viewpoint of ease of use, and as described in Patent Document 1, general trolleys are already in the mainstream as inexpensive. In addition, rust resistance is also required for special transport carts such as food carts and medicinal carts, and these current products are mainly made of SUS304 (austenitic stainless steel) in consideration of rust resistance. It's being used. Thus, SUS304 is soft, and it is necessary to design the member to a certain thickness in consideration of strength. Therefore, it is difficult to reduce the thickness and weight, and the unit cost of the material is high. .
In the same stainless steel, SUS420J2 (martensitic stainless steel) is also available. This material can be strengthened by heat treatment (quenching and tempering), so it can be reduced in thickness and weight, but contains nickel (Ni). Since it is not rust-proof, it is necessary to apply nickel plating after the heat treatment, and as a result of the addition of a plating step, the use of this material does not lead to cost reduction.

  In addition, when the weight is reduced by using a thin-walled member, the main base part on the mounting part side and the side base member on the fixed side of the caster part are manufactured separately, and are combined and integrated. However, if the bolts and nuts protrude, there is a risk of damaging the surroundings. Therefore, for special transport carts, the installation method is also required.

JP 2008-049801 A

  In order to solve the above-mentioned problems, the present invention provides various conveying carts including special ones that have been reduced in weight in a cost-appropriate manner by adopting thin-walled members excellent in strength and rust-proofing properties and structural devices. Its purpose is to provide.

  The present invention has been made to solve the above problems, and the invention of claim 1 includes a main base portion, a side base member disposed below the main base portion and serving as a mounting portion for the caster portion. A channel-shaped main base member that forms a part of the main base portion, has a cross-section in a channel shape, and is opposed to the lip portions on both sides on the lower side that is the mounting side of the caster portion, and the channel shape The main base member is closed from the lower side, the side base member in which the opposite edge portions are overlapped with the lip portions on both sides, and the channel-shaped main base member are inserted, and the opposite edge portions are A lip portion overlapped with the lip portions on both sides, and the lip portion by tightening and fixing the side base member to the lip plate member. Through which attached to the main base portion, the main base portion, the side base member and the passing plate member is a transport carriage, characterized in that it is hardened to form the thin martensitic stainless steel.

  According to a second aspect of the present invention, in the conveyance carriage according to the first aspect, the transfer plate member is provided with a spring property by bending both edge portions superimposed on the lip portions on both sides. It is a trolley.

  According to a third aspect of the present invention, in the conveying cart according to the first or second aspect, the transfer plate member has a nut and is attached by tightening with a bolt and nut.

  According to a fourth aspect of the present invention, in the conveyance carriage according to the third aspect, a bolt insertion hole is formed in the caster portion, and the caster portion is also tightened with a bolt nut by using the bolt insertion hole. It is the conveyance cart characterized by being attached to.

According to a fifth aspect of the present invention, in the transport cart according to any one of the first to fourth aspects, the main base member and the side base member have a flat surface portion that constitutes a placement surface. A transport cart characterized by a large number of holes .

The invention of claim 6 is the method for manufacturing a transport carriage according to any one of claims 1 to 5, wherein the main base member, the side base member and the transfer plate member are formed into a thin wall shape from niobium-containing martensitic stainless steel. In addition , the present invention is a method for manufacturing a transport carriage characterized in that it is formed by quenching hydrogen gas or a hydrogen-based mixed gas as a cooling gas .

  The conveyance cart of the present invention has succeeded in reducing the weight in a form commensurate with cost by adopting a thin member excellent in strength and rust prevention and structural ingenuity.

It is the perspective view seen from the mounting side of the conveyance trolley which concerns on embodiment of this invention. It is the perspective view seen from the wheel side of the conveyance trolley | bogie of FIG. FIG. 3 is an exploded perspective view of FIG. 2. FIG. 3 is a cross-sectional view of the transfer plate member of FIG. 2. It is sectional drawing of the assembly state of FIG. It is a top view of the channel-shaped main base member and side base member of another example. It is a perspective view of the conveyance trolley manufactured using the board in which the elliptical punch hole was opened.

A transport cart 1 according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the main base portion 3 includes two types of channel-shaped main base members 5 and 19, and another channel-shaped main base member is interposed between the pair of channel-shaped main base members 5 and 5. 19 is arranged. Three channel-shaped main base members 5, 19, 5 are arranged in parallel with each other in the longitudinal direction, and when viewed from above, a mounting surface 21 having a rectangular shape and an upper surface flush with each other is formed. Yes.

As shown in FIGS. 2 and 3, the channel-shaped main base member 5 is formed in a channel shape by bending the both ends in the width direction of the strip-shaped thin plate to the same plate surface side. The intermediate plane portion 7 is flat and constitutes a part of the mounting surface 21 described above. The bent portion includes side portions 9 and 9 bent perpendicularly to the flat portion 7 and lip portions 11 and 11 bent perpendicularly to the side portions 9 and 9. The plate surfaces of the lip portions 11 and 11 are parallel to the plate surface of the flat surface portion 7, and the edges 13 and 13 are opposed to each other with a space therebetween.
Reference numeral 15 denotes a rectangular hole for receiving a wheel (FIG. 1). The rectangular hole 15 is formed by penetrating two places on both ends in the longitudinal direction of the flat portion 7. A wheel bracket 17 is provided corresponding to the rectangular hole 15.

  The channel-shaped main base member 19 is configured in the same manner as the channel-shaped main base member 5 except that the dimension in the width direction is slightly small and no wheel receiving hole and metal fitting are provided.

Reference numeral 23 denotes a transfer plate member. As shown in an enlarged view in FIG. 3, the transfer plate member 23 is formed of a thin plate and has a rectangular shape close to a square. A pair of facing edge portions 25 and 25 of the transfer plate member 23 are bent and inclined, and a plate spring is formed by utilizing the elastic force of the material. In addition, the edge parts 25 and 25 of both sides are bend | folded to the same side.
Bolt insertion holes 29 are formed near the four corners of the flat portion 27 of the transfer plate member 23, and nuts 31 (FIG. 4) are attached to the respective bolt insertion holes 29 by welding. All the nuts 31 are arranged on the same plate surface side.

The transfer plate member 23 corresponds to the channel-shaped main base member 5, and another transfer plate member 33 corresponds to the channel-shaped main base member 19.
The transfer plate member 33 is smaller than the transfer plate member 23 and has a rectangular shape, and the length of the edge portion 25 is approximately halved.

Reference numeral 35 denotes a side base member, and the side base member 35 is formed of a thin plate. Side portions 39, 41, 39 are formed by vertically bending portions that are connected to the three sides of the rectangular flat portion 37, and the side portions 41 are connected to the long sides.
Holding parts 43, 43 are attached to the side part 41 near the corners on both sides where the side parts 41, 39 are adjacent, and the fitting pipe 45 is held by the holding part 43 and the side part 41. It is held. The holding part 43 and the fitting pipe 45 are each fixed by welding.
The flat portion 37 has bolt insertion holes 47 formed at 10 locations.

  Reference numeral 49 denotes a caster portion, and a wheel 53 is rotatably attached to an attachment plate 51 of the caster portion 49. Bolt insertion holes 55 are formed at the four corners of the mounting plate 51.

The above are constituent members on the base portion side of the transport carriage 1, and the assembly method will be described below.
First, the channel-shaped main base members 5, 19, 5 are arranged in parallel at a predetermined interval.
Next, in the state where the transfer plate member 23 is inserted into the channel-shaped main base member 5 and bridged between the lip portions 11, 11, the edge portions 25, 25 on both sides are placed on the lip portions 11, 11 and overlapped. . At this time, since the edge portion 25 is inclined, the intermediate plane portion 27 is lifted. The transfer plate member 23 is provided at a position facing the wheel bracket 17, and two transfer plate members 23 are arranged for one channel-shaped main base member 5.
Similarly, the transfer plate member 33 is inserted into the channel-shaped main base member 19.

  In this state, the side base member 35 is fitted into the channel-shaped main base members 5, 19, 5 from below, and the pair of side surface portions 39, 39 are connected to the side surface portions 9 of the one channel-shaped main base member 5. And the other side surface portion 41 of the channel-shaped main base member 5 is overlapped with the other side surface portion 41 and the other side surface portion 41 is overlapped with the longitudinal ends of the channel-shaped main base members 5, 19, 5. A pair of side base members 35 are prepared, and the other ends in the longitudinal direction of the channel-shaped main base members 5, 19, 5 are similarly covered.

Furthermore, when the mounting plate 51 of the caster part 49 is overlapped on the side base member 35 from the lower side, the constituent members are combined. As shown in FIG. 3, the four bolt insertion holes 55 of the caster part 49, the four bolt insertion holes 47 of the side base member 35, the four bolt insertion holes 29 of the transfer plate member 23, and the nut 31 are aligned. After communicating, tighten through bolts 57.
As a result, the side base member 35 is attached to the channel-shaped main base member 5, and at the same time the caster part 49 is attached to the side base member 35.
By tightening, the flat portion 27 of the transfer plate member 23 is pressed against the flat portion 7 side of the channel main base member 5 and elastically deforms to serve as a spring washer, so that the bolt 57 is prevented from loosening.

Since the caster portion 49 is not attached to the channel-shaped main base member 19, the two bolt insertion holes 47 of the side base member 35, the two bolt insertion holes 29 of the transfer plate member 33, and the nut 31 are communicated. The side base member 35 is attached to the channel-shaped main base member 5 by tightening through the bolts 57. Also in this case, the transfer plate member 33 operates in the same manner as the transfer plate member 23.
In the drawing, it is assumed that the above-described assembly and tightening operations are normally performed upside down in consideration of work convenience so that the channel-shaped main base members 5 and 19 always face upward. Yes.

  As described above, the base portion side of the transport carriage 1 is configured, and the thin-walled side base members 35 are attached to the channel-shaped main base members 5 and 19 configured in a channel shape so as to be thin and strong. The overall weight reduction has been achieved. Moreover, the bolts 57 and the nuts 31 for tightening are arranged on the bottom side of the carriage, and neither of them is exposed on the top surface or the side surface side of the channel-shaped main base members 5 and 19 or the side base member 35. Therefore, there is no fear of damaging the surroundings. Moreover, since the nut 31 is attached to the transfer plate members 23 and 33 in advance, the work at the site is also facilitated.

  In the carriage 1, a support pipe (not shown) is fitted into the fitting pipe 45 of the side base member 35 and fixed by welding, and another support table is provided on the support pipe, or a handle for pushing ( (Not shown in the drawings) is provided to obtain a finished product. However, the above-described base portion is a feature of the present invention, and description of other portions is omitted.

The raw materials of the channel-shaped main base members 5 and 19 and the side base member 35 are both made by increasing C (carbon) and adding Nb (niobium) based on “SUS410 13Cr series”. “SUS420J2” is an example in which C (carbon) is increased, and the present invention is classified into 13Cr—Nb-0.25C, to which Nb (niobium) is added. As a material corresponding to this, “NSS WR-1” (high-strength martensitic stainless steel) is commercially available from Nisshin Steel Co., Ltd.
The data comparing chemical components of “NSS WR-1”, “SUS420J2”, and “SUS301H” of SUS304 18Cr—Ni are as follows, and there is a significant difference in the content of niobium.

At the material stage, it is in a cold-rolled plate state.
From this material, as described above, each member is shaped and heat-treated.
The heat treatment is quenching / tempering. In the quenching, hydrogen gas or a hydrogen-based mixed gas is used as a cooling gas after raising the temperature to the quenching temperature. Here, the hydrogen-based mixed gas is a mixed gas of hydrogen gas and an inert gas, for example, argon gas, and it is assumed that the hydrogen gas contains 80% or more, for example, 85%. By using a cooling gas and increasing the cooling rate, the precipitation of chromium carbide, which is the cause of cracking, is eliminated and the addition of niobium ensures sufficient rust prevention. In addition, due to the gas cooling effect, it is difficult to cause uneven processing on the surface, and furthermore, the oxide on the surface is reduced due to the hydrogen effect, making final finishing treatment such as shot blasting unnecessary and suitable for processing thin-walled members. .
From the viewpoint of the working environment, it is preferable that the above-mentioned quenching bring the object to be processed into a predetermined gas atmosphere using a belt conveyor type oxygen-free gas furnace using a SUS belt. The quenching temperature is preferably around 1050 ° C., and the heating and holding time is preferably about 15 minutes.
Tempering is preferably performed using a thermostatic oven and naturally cooled. The tempering temperature is preferably around 200 ° C., and the heating and holding time is preferably about 30 minutes.

  This material has sufficient bending workability in an untreated stage, has sufficient strength after quenching and tempering, and has rust prevention properties. For this reason, a material having a thickness of 1.6 mm or less can be used as a material for the base member of the transport carriage. By using SUS304 in combination according to the part, such as attaching the nut 31 made of a spot by spot welding, it is possible to successfully make a base portion that is significantly reduced in weight.

As shown in FIG. 6, the channel-shaped main base members 5 and 19 and the side base member 35 can be further reduced in weight by providing a large number of oval holes 59 in the flat portions 7 and 37. A punched base member can be easily manufactured by punching and bending a plate-shaped material.
There has never been a cart with a perforated structure on the flat surface. If the upper and middle plate portions of the multi-stage cart are also perforated, the weight of the entire cart can be further reduced. Moreover, when applied to a freezer cart, there is an advantage that the passage of cold air in the vertical direction can be ensured.

<Confirmation of mechanical properties>
As a material, plate materials of the steel types shown in Table 1 (plate thickness 0.4 mm) were selected, and their mechanical properties were confirmed.
“NSS WR-1” and “SUS420J2” confirmed the annealed material and the treated material after heat treatment, respectively. The quenching was performed by using a belt-type oxygen-free furnace made of SUS and using 100% hydrogen gas as a cooling gas, a quenching temperature of 1050 ° C., and a heating and holding time of 15 minutes. In addition, tempering was performed using an external natural cooling using a thermostatic oven with a tempering temperature of 200 ° C. and a heating and holding time of 30 minutes.
“SUS301H” was not heat-treated, and only the rolled material was confirmed.

引張強さは、圧延に平行な方向とした。
「ＮＳＳ ＷＲ−１」は、素材（焼鈍材）段階では、十分な加工性を備え、台車のベース部材として有用なことが確認された。

The tensile strength was a direction parallel to rolling.
It was confirmed that “NSS WR-1” has sufficient workability at the material (annealed material) stage and is useful as a base member of a carriage.

<Manufacture of side base members>
Next, the side base member 35 having the above-mentioned shape was manufactured with a plate thickness of “SUS304” being 3.0 mm of the current product and “NSS WR-1” being 1.6 mm. It was confirmed that the side base member 35 can be a sufficient substitute for “SUS304” in terms of strength and the like by being quenched. Moreover, the surface was clean and the weight was halved from the current product.
<Manufacture of channel-shaped main base member>
In the same manner as described above, the channel-shaped main base member of the current product and the product of the present invention was manufactured. However, the thickness of the material of the present invention was 1.3 mm, which was the limit, and a plate having an oval punch hole as shown in FIG. 6 was used.
The product of the present invention also has a beautiful surface, and the weight is more than halved by 65% compared to the current product.
FIG. 7 shows a transport carriage (actual) 61 formed by using a plate with an oval punch hole as a base member. A punch hole 65 is formed in a flat portion of the channel-shaped main base member 63. Are in an aligned state. The side base member 67 is also formed of a plate having an oval punch hole.

Resource saving is very important for Japan, which has few resources in the era of high resources, especially if the weight of the parts can be reduced, not only will the finished product be easy to handle, but also the manufacturing and assembly processes of the parts, The effect also affects the transportation of members, and fuel efficiency can be improved. In recent years, there has been a demand for CO ₂ reduction due to environmental problems, but this CO ₂ reduction request can be answered by improving fuel efficiency.
In addition, although it is a stainless steel special steel, the material cost is lower than the stainless steel currently used, and even if heat treatment such as quenching and tempering is added, the selling price is lower than the current product.

DESCRIPTION OF SYMBOLS 1 ... Conveyance trolley 3 ... Main base part 5, 19 ... Channel-shaped main base member 7 ... Plane part 9 ... Side face part 11 ... Lip part 13 ... Edge 15 ... Rectangular hole 17 for wheel receiving ...... Wheel catch 21 ... Placement surface
23 …… Transfer plate member 25 …… Inclined edge portion 27 …… Plane portion 29 …… Bolt insertion hole 31 …… Nut 33 …… Transfer plate member 35 …… Side base member 37 …… Plane portion 39 …… Side portion ( Short side) 41 …… Side face (long side)
43 …… Holding part 45 …… Fitting pipe 47 …… Bolt insertion hole 49 …… Caster part 51 …… Mounting plate 53 …… Wheel 55 …… Bolt insertion hole 57 …… Bolt 59 …… Hole 61 …… Conveyance Carriage (actual) 63 …… Channel-shaped main base member 65 …… Punch hole 67 …… Side base member

Claims (6)

In a transport carriage including a main base portion and a side base member that is disposed on the lower side of the main base portion and serves as an attachment portion of the caster portion,
A channel-shaped main base member that forms a part of the main base portion, and has a channel-shaped cross section, with the lip portions on both sides facing each other on the lower side that is the mounting side of the caster portion;
A side base member in which the channel-shaped main base member is closed from the lower side, and both opposing lip portions are superimposed on the lip portions on both sides;
A connecting plate member inserted into the channel-shaped main base member, the opposite edge portions of which are overlapped with the lip portions on both sides;
By tightening and fixing the side base member to the transfer plate member, the side base member is attached to the main base portion via the lip portion,
The main base part, the side base member, and the transfer plate member are made of martensite stainless steel and are thinly quenched and hardened. In the conveyance trolley | bogie described in Claim 1,
The transfer carriage member is characterized in that both edge portions superimposed on the lip portions on both sides are bent and provided with spring properties. In the conveyance cart according to claim 1 or 2,
The transfer board member is provided with a nut, and the side base member is attached to the main base portion by tightening with a bolt and nut. In the conveyance trolley | bogie described in Claim 3,
Bolt insertion holes are formed in the caster part, and the caster part is also attached to the side base member by tightening with a bolt nut using the bolt insertion hole. In the conveyance trolley | bogie as described in any one of Claims 1-4,
The main base member and the side base member have a flat surface portion constituting a mounting surface, and a plurality of holes are formed in the flat surface portion . In the manufacturing method of the conveyance trolley in any one of Claims 1-5,
The main base member, the side base member, and the transfer plate member are formed of a niobium-containing martensitic stainless steel thinly formed and quenched with hydrogen gas or a hydrogen-based mixed gas as a cooling gas. A method of manufacturing a cart.

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