Furniture with legs

Abstract

To provide furniture with legs that not only achieves a stable structure through concrete legs, but also reduces the burden of transportation and installation work during construction, and makes repairs after installation easy. [Solution] A piece of furniture with legs B is constructed by attaching a top plate 2 to legs 1 positioned on both the left and right sides. The legs 1 are made of concrete members that are divided into upper and lower sections, and the upper member 11 and the lower member 12 are configured to be integrated by interlocking protrusions and recesses. In the connection between the legs 1 and the top plate 2, a screw insertion hole is formed on the upper surface side of the upper member of the leg, and the top plate and the lower member of the leg are connected by passing a screw member through this screw insertion hole.

Description

Technical Field

[0001] The present invention relates to furniture with legs such as benches and tables.

Background Art

[0002] In benches, tables, etc. used indoors and outdoors, it is common to configure them by attaching a seat board or a tabletop to the left and right legs. Also, in outdoor benches, etc., those made of concrete formed into a predetermined shape are known (see Patent Documents 1 and 2). Since such concrete legs are heavy and have excellent durability, they are suitable for outdoor use.

[0003] However, in the above-mentioned conventional concrete legs, when installing a bench, etc. outdoors, workers need to carry the heavy legs, so there is a problem that the construction burden becomes large. Also, after installing a bench, etc., if the concrete legs are damaged by an impact from the outside, etc., it is necessary to replace the entire legs, so the burden during repair is also large. [[ID=၁၈]]

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to solve the problems of the above-mentioned conventional technology, and in summary, it is to provide furniture with legs that can realize a stable structure by concrete legs, have a small work burden for transportation and installation during construction, and can be easily repaired after installation.

Means for Solving the Problems

[0006] As a means of solving the above problems, the inventor has created a piece of furniture with legs B, which is constructed by attaching a top plate 2 to legs 1 arranged on both the left and right sides, in which the legs 1 are made of concrete members that are divided into upper and lower parts, and the upper member 11 and the lower member 12 are made to be integrated by interlocking grooves and protrusions (the effects will be described later).

[0007] In this invention, the upper member 11 of the leg portion 1 is constructed from a hollow shape with an opening on the bottom side, and the upper member 11 is configured to be placed over the lower member 12 and integrated, so that even if the upper member 11 that is exposed to the outside is damaged, it can be easily replaced.

[0008] In the present invention, when the upper member 11 of the leg portion 1 is placed over the lower member 12, a clearance C in the left-right direction is formed at least between the inner walls of the lower member 12 and the upper member 11, so that even if the upper member 11 is subjected to an impact from the side, the impact can be dissipated by the clearance C.

[0009] In this invention, vertical ribs 11h are formed on one or both of the left and right inner walls within the hollow portion of the upper member 11 of the leg portion 1, and vertical guide grooves 12f corresponding to the position and shape of the ribs 11h are formed in the lower member 12 of the leg portion 1, so that the ribs 11h can be fitted into the guide grooves 12f, thereby allowing the upper member 11 to be attached to the lower member 12 by lowering it straight down. Furthermore, the left and right wall surfaces of the upper member 11 can also be reinforced by the ribs 11h.

[0010] In this invention, in connecting the leg portion 1 and the tabletop 2, a screw insertion hole 11e is formed on the upper surface side of the upper member 11 of the leg portion 1, and a screw member is passed through this screw insertion hole 11e to connect the upper member 11 and the lower member 12 of the leg portion 1. Furthermore, if the screw insertion hole 11e is made slightly larger than the screw member, a gap can be formed between the screw member and the hole, so that even if the upper member 11 is subjected to an impact from the side, a slight displacement of the upper member 11 can be tolerated.

[0011] In this invention, a protrusion 11f is formed on the inner surface of the upper member 11 of the leg portion 1, around the screw insertion hole 11e, and when the upper member 11 of the leg portion 1 is placed over the lower member 12, the protrusion 11f is brought into contact with the upper surface of the lower member 12, thereby creating an upper clearance C when the upper member 11 is placed over the lower member 12. Furthermore, since a load is applied to the contact surface between the protrusion 11f of the upper member 11 and the upper surface of the lower member 12 when the leg portion 1 is integrated, displacement of the screw insertion hole 11e is less likely to occur even if the upper member 11 is subjected to an impact from the side.

[0012] In this invention, the thickness of the left and right wall surfaces of the upper member 11 of the leg portion 1 is formed such that the bottom side is thinner and the top side is thicker, and the area of ​​the cross-section of the hollow portion decreases from the bottom side to the top side. This reduces the thickness of the bottom side and makes the opening on the bottom side of the upper member 11 larger, making it easier to place the upper member 11 over the lower member 12. [Effects of the Invention]

[0013] The furniture with legs of the present invention is constructed by dividing the concrete legs into an upper and lower member, and by configuring these upper and lower members to be able to be integrated by interlocking grooves and protrusions. As a result, the legs can be transported and installed separately, reducing the workload during construction. Furthermore, even if the legs are damaged by an external impact after installation, only the upper member needs to be removed and replaced, thus reducing the workload during repairs. [Brief explanation of the drawing]

[0014] [Figure 1] These are a front view, a top view, and a right side view showing a piece of furniture with legs according to the first embodiment of the present invention. [Figure 2] (a) an exploded perspective view and (b) a front view and a top view of the mounting bracket, illustrating the structure of a legged furniture piece according to the first embodiment of the present invention. [Figure 3] (a) Front view, inner side view, top view, bottom view and (b) AA cross-sectional view and BB cross-sectional view showing the leg portion of the first embodiment of the present invention. [Figure 4] (a) Front view, inner side view, top view, bottom view, and (b) AA cross-sectional view, (c) BB cross-sectional view, and (d) CC cross-sectional view, which represent the upper member of the first embodiment of the present invention. [Figure 5] (a) Front view, inner side view, top view, bottom view, and (b) AA cross-sectional view and (c) BB cross-sectional view, which represent the lower member of the first embodiment of the present invention. [Modes for carrying out the invention]

[0015] "First Embodiment" A first embodiment of the present invention will be described with reference to Figures 1 to 5. In the figures, the part indicated by reference numeral B is a piece of furniture with legs, the part indicated by reference numeral 1 is the leg of the piece of furniture with legs, the part indicated by reference numeral 2 is the tabletop of the piece of furniture with legs, and the part indicated by reference numeral 3 is the mounting bracket for the leg and the tabletop. In this embodiment, the directions "up and down," "left and right," and "front and back" refer to the directions when the piece of furniture with legs is viewed from the front.

[0016] "Construction and assembly methods for furniture with legs" [1] About the basic configuration The basic configuration of the legged furniture B of this embodiment will now be described. In this embodiment, as shown in Figures 1 and 2, the bench-type legged furniture B is constructed by attaching a top plate 2 to leg portions 1 arranged on both the left and right sides, and as shown in Figures 3 to 5, the leg portions 1 are constructed from concrete members that are divided into upper and lower sections. Furthermore, these leg portions 1 are configured to be integrated by fitting the upper member 11 and the lower member 12 together using a groove-and-groove mechanism.

[0017] With the above configuration, even a heavy concrete leg 1 can be made lighter by dividing it into an upper member 11 and a lower member 12, making it easier to transport and install the leg 1. In particular, when the legged furniture B of this embodiment is used as an outdoor bench, it can be transported outdoors efficiently, and the assembly work can be safely performed by workers holding the upper member 11 and lower member 12 by hand.

[0018] [2] Assembly method The assembly method of the furniture B with legs shown in FIG. 1 of the present embodiment will be briefly described. In the present embodiment, after installing the lower member 12 of the leg portion 1 shown in FIG. 5 on the construction surface (ground), by covering the upper member 11 shown in FIG. 4 with the lower member 12 and integrating them, the leg portion 1 shown in FIG. 3 can be formed. Further, the mounting bracket 3 is fixed to the top plate 2 with bolts, and this mounting bracket 3 is placed on the leg portion 1, and the mounting bracket 3 and the leg portion 1 are fastened with screw members. Thereby, the furniture B with legs can be easily assembled on-site.

[0019] [3] Regarding the leg portion [3-1] Overall shape of the upper member Next, each component of the furniture B with legs will be described. Regarding the upper member 11 of the leg portion 1, in the present embodiment, as shown in FIG. 4, it has a rectangular parallelepiped shape having an upper surface portion 11a, front and rear side surface portions 11b, and left and right side surface portions 11c, and has a hollow shape (half-cylindrical shape) with an opening 11d on the bottom side. Thus, as shown in FIG. 3, the upper member 11 can be covered with the lower member 12 and integrated. Even if the upper member 11 exposed on the outside is damaged, only the upper member 11 can be removed and easily replaced.

[0020] Regarding the shape of the upper member 11 of the leg portion 1, in the present embodiment, the lower member 12 has a convex shape and the upper member 11 has a concave shape and they are fitted with each other in a concave-convex manner. However, the concave and convex shapes can be reversed up and down so that the upper member 11 has a convex shape and the lower member 12 has a concave shape. Also, as the overall shape of the upper member 11, a rectangular parallelepiped shape that is easy to form with concrete is preferable, but other shapes (for example, polygonal prism shape, semi-elliptical shape, etc.) can also be adopted. Also, the corners formed on the outer periphery of the upper member 11 are chamfered so that the operator does not get injured.

[0021] [3-2] Screw insertion holes of the upper member As shown in Figures 4(a) and 4(b), a screw insertion hole 11e is formed on the upper surface 11a side of the upper member 11 of the leg portion 1. This allows the upper member 11 and the lower member 12 of the leg portion 1 to be connected by passing a screw member through the screw insertion hole 11e. Furthermore, if the screw insertion hole 11e is made slightly larger than the screw member, a clearance can be created between the screw member and the hole, allowing for slight displacement of the upper member 11 even if the upper member 11 is subjected to an impact from the side.

[0022] In this embodiment, the screw insertion holes 11e of the upper member 11 are formed in two locations, front and back, as shown in Figure 4(a). However, the number of screw insertion holes 11e can be three or more depending on the depth of the leg portion 1, and they can also be formed in two or more rows on the left and right sides depending on the width of the leg portion 1. The diameter of the screw insertion holes 11e can be appropriately changed depending on the screw member used.

[0023] [3-3] Protrusion of the upper member As shown in Figures 4(a) and 4(b), a protrusion 11f is formed on the inner surface of the upper member 11 of the leg portion 1, around the screw insertion hole 11e. By bringing this protrusion 11f into contact with the upper surface of the lower member 12 when the upper member 11 is placed over the lower member 12, as shown in Figures 3(a) and 3(b), a clearance C corresponding to the height of the protrusion 11f can be formed between the upper member 11 and the lower member 12, as shown in Figures 3(a) and 3(c). Furthermore, since a load is applied to the contact portion between the protrusion 11f of the upper member 11 and the upper surface of the lower member 12 when the leg portion 1 is integrated, displacement of the screw insertion hole 11e is less likely to occur even if the upper member 11 is subjected to an impact from the side.

[0024] In this embodiment, the protrusion 11f of the upper member 11 is formed in a groove-like shape extending between the inner walls of the left and right side portions 11c, as shown in the bottom view of Figure 4(a). However, it can also be partially formed in a concentric or angular shape around the screw insertion hole 11a. Furthermore, the height of the protrusion 11f can be appropriately changed according to the required clearance C.

[0025] [3-4] Stepped portion of the upper member As shown in Figures 4(a), 4(b), and 4(c), a stepped portion 11g is formed on the upper surface of the upper member 11 of the leg portion 1, recessed one step from the upper end. This stepped portion 11g is formed to support the mounting bracket 3, as shown in Figure 2(a), for connecting the upper member 11 and the lower member 12, as well as the leg portion 1 and the top plate 2. In this embodiment, since this stepped portion 11g is formed on the inner left and right walls, it is possible to reach in from the inside to fasten and loosen the mounting bracket 3 when connecting the leg portion 1 and the top plate 2. Furthermore, by not forming this stepped portion 11g on the front, rear and left and right outer walls, the mounting bracket 3 can be hidden so that it is not exposed when viewing the leg-equipped furniture B from the front, rear, left, or right, as shown in Figure 1.

[0026] The shape of the stepped portion 11g is not limited to this embodiment, and it can also be partially formed in the area where the mounting bracket 3 is placed. Furthermore, the depth of the stepped portion 11g needs to be smaller than the height of the mounting bracket 3 shown in Figure 2(b), but it is preferable to make it only slightly smaller in order to reduce the gap between the leg portion 1 and the top plate 2.

[0027] [3-5] Size of the hollow portion of the upper member Regarding the size of the hollow portion of the upper member 11 of the leg portion 1, as shown in Figures 3(b) and 3(c), in this embodiment it is formed to be slightly larger than the outer circumference of the lower member 12. This allows a clearance C in the left-right direction (preferably in the front-back and left-right directions) to be formed between the inner walls of the lower member 12 and the upper member 11 when the upper member 11 of the leg portion 1 is placed over the lower member 12. Therefore, even if the upper member 11 is subjected to an impact from the left-right direction (preferably in the front-back and left-right directions), the impact can be dissipated by the clearance C. The size of the hollow portion of the upper member 11 can be appropriately changed depending on the required clearance C.

[0028] [3-6] Thickness of the side wall of the upper member In this embodiment, the thickness of the wall surfaces forming the front and rear side portions 11b and the left and right side portions 11c of the upper member 11 of the leg portion 1 is such that, as shown in Figures 4(a), (b), and (c), the bottom side is thinner and the top side is thicker, so that the area of ​​the cross-section of the hollow portion decreases from the bottom side to the top side. This makes it easier to place the upper member 11 over the lower member 12 by reducing the thickness of the bottom side and increasing the opening 11d on the bottom side of the upper member 11.

[0029] [3-7] Ribs on the inside of the upper member In this embodiment, as shown in Figures 4(a), (c), and (d), vertical ribs 11h are formed on one of the left and right inner walls within the hollow portion of the upper member 11 of the leg portion 1. This allows the left and right wall surfaces of the upper member 11 to be reinforced by the ribs 11h, and also allows for smooth attachment to the lower member 12 (details will be explained in the section on the lower member). These ribs 11h are formed only on the left and right inner side walls so that the left and right orientation of the upper member 11 can be determined (to prevent it from being mistakenly attached in the wrong direction), but they can also be formed on the left and right outer side walls. Furthermore, ribs 11h can be formed on both the left and right side walls as needed.

[0030] Regarding the cross-sectional shape of the rib 11h, it is trapezoidal as shown in the bottom view of Figure 4(a) and Figure 4(d) to enhance the above effect, but the cross-sectional shape is not limited to this. In this embodiment, the left and right width of the rib 11h is made smaller on the bottom side and larger on the top side to facilitate attachment to the lower member 11. In this embodiment, only one rib 11h is formed, but the number of ribs 11h can also be made in multiples depending on the depth of the leg portion 1. In this embodiment, the vertical length of the rib 11h is made shorter than the side wall as shown in Figures 4(a) and 4(c) to prevent the rib 11h from interfering with the lower member 12 at the opening on the bottom side.

[0031] [3-8] Overall shape of the lower member As shown in Figure 5(a), the lower member 12 of the leg portion 1 has a pyramidal shape, with a top surface 12a, front and rear side surfaces 12b, left and right side surfaces 12c, and a bottom surface 12d. The pyramidal shape of the lower member 12 corresponds to the shape of the hollow portion of the upper member 11, making it easier to place the upper member 11 over the lower member 12. The overall shape of the lower member 12 can also be a rectangular parallelepiped or an elliptical cylinder, depending on the shape of the hollow portion of the upper member 11. Furthermore, the corners of the lower member 12 are chamfered to prevent injury to workers.

[0032] [3-9] Nut member of the lower member As shown in Figures 3 and 5(a)(b), a nut member 12e is embedded in the upper surface 12a of the lower member 12 of the leg 1 at a position corresponding to the screw insertion hole 11e of the upper member 11. This allows the members to be connected and fixed by fastening the screw members inserted into the mounting bracket 3 and the screw insertion hole 11e of the upper member 11 to the nut member 12e of the lower member 12. The number, arrangement, and type of nut members 12e can be appropriately changed according to the depth and width of the leg 1.

[0033] [3-10] Guide groove of the lower member In this embodiment, as shown in Figures 5(a) and 5(c), vertical guide grooves 12f are formed on the left and right side portions 12c located on the left and right inner sides of the lower member 12 of the leg portion 1, corresponding to the position and shape of the rib 11h of the upper member 11. As a result, as shown in Figures 3(a) and 3(c), the rib 11h of the upper member 11 can be fitted into the guide groove 12f of the lower member 12, and the upper member 11 can be smoothly attached to the lower member 12 by lowering it along the guide groove 12f.

[0034] In this embodiment, the cross-sectional shape of the guide groove 12f of the lower member 12 is set to a trapezoidal shape corresponding to the rib 11h, as shown in Figure 5(a), and the width of the guide groove 12f is made larger on the top side and smaller on the bottom side. This makes it easier to insert the rib 11h of the upper member 11 into the guide groove 12f of the lower member 12. The shape and number of guide grooves 12f of the lower member 12 can be appropriately changed according to the shape and number of the corresponding ribs 11h.

[0035] [3-11] Height of the lower member As shown in Figures 3(a), 3(b), and 3(c), the vertical height of the lower member 12 of the leg portion 1 is made greater than the height of the hollow portion of the upper member 11. This allows the lower end of the upper member 11 to be suspended above the ground when the upper member 11 is placed over the lower member 12. With the upper member 11 suspended above the ground, its own weight is concentrated on the protrusion 11f on the upper surface that is in contact with the lower member 12.

[0036] [3-12] Bottom surface of the lower member Regarding the bottom surface 12d of the lower member 12 of the leg 1, a different form from that of this embodiment can be adopted. For example, a metal base can be provided for bolting and fixing the leg 1 to the ground. In addition, an inclined surface or a stepped surface can be formed on the bottom surface 12d of the lower member 12 depending on the shape of the surface on which the leg 1 is installed.

[0037] [3-13] Materials of the upper and lower members Regarding the materials for the upper member 11 and lower member 12 of the leg 1 described above, if concrete is used as the main material, other materials (for example, metal materials or plastic materials) can be used in part. Specifically, concrete reinforcing materials such as reinforcing bars, steel materials, and fiber reinforcement materials can also be used.

[0038] [4] About the tabletop [4-1] Overall configuration of the tabletop Regarding the tabletop 2 described above, in this embodiment, since the legged furniture B is used as a bench, it is configured to be used as a seat. Specifically, as shown in Figures 1 and 2, multiple boards 21 are aligned in the length direction and arranged in the width direction, and connecting plates 22 are placed across the back surfaces of these boards 21 in the width direction, connecting each board 21 to form the tabletop 2. In this embodiment, multiple boards 11 are used for the tabletop 2, but the dimensions, number, and shape of the boards 21 can be appropriately changed according to the shape of the legged furniture B, and the tabletop 2 can also be constructed from a single wide board 21.

[0039] [4-2] Plate material In this embodiment, since the legged furniture B is used as an outdoor bench for long-term outdoor use, a lightweight, hollow wood-powder-containing plastic sheet with excellent weather resistance and durability is used for the board material 21. However, the material of the board material 21 is not particularly limited, and for example, wood (solid wood, laminated wood, plywood, etc.) or metal materials can also be used. It is also possible to use a combination of board materials 21 made of different materials.

[0040] [4-3]Connection plate Regarding the connecting plates 22 of the tabletop 2 described above, a metal plate is used in this embodiment, but it is not particularly limited to any material that has sufficient strength. The connecting plates 22 placed on both the left and right sides of the tabletop 2 are positioned according to the positions of the legs 1 shown in Figures 1 and 2, and multiple connecting plates 22 placed in the middle can be attached at predetermined intervals according to the width of the tabletop 2. These connecting plates 22 have screw holes for fastening them to the plate material 22 and screw holes for fixing them to the mounting bracket 3 shown in Figure 2.

[0041] [5] Mounting hardware [5-1] Overall shape of the mounting bracket Regarding the mounting bracket 3 described above, as shown in Figure 2(b), it has a shape that includes a top plate mounting surface 31 formed in a wing shape on both sides, and a leg mounting surface 32 in the middle section connecting these two top plate mounting surfaces 31. The shape of this mounting bracket 3 is not limited to the shape of this embodiment as long as it has a top plate mounting surface 31 on the upper side and a leg mounting surface 32 on the lower side; for example, a U-shaped cross section can also be adopted. In this embodiment, the height of the mounting bracket 3 is adjusted by creating a step between the top plate mounting surface 31 and the leg mounting surface 32, but the size of the step and the height of the mounting bracket can be changed as needed.

[0042] [5-2] Screw insertion holes for mounting brackets The mounting bracket 3 described above has screw insertion holes 33 on the top plate mounting surface 31 and the leg mounting surface 32, respectively, and a screw member can be inserted into these screw insertion holes 33 to attach it to the leg 1 or top plate 2. In this embodiment, the screw insertion holes 33 of the mounting bracket 3 are positioned towards the left and right inner sides of the leg-mounted bracket B, but the arrangement and number of screw insertion holes 33 can be appropriately changed according to the arrangement and number of screw holes in the top plate 1 or leg 2.

[0043] In this embodiment, the mounting bracket 3 is configured as described above. Therefore, when assembling the legged furniture B, a fully threaded long screw is inserted into the screw insertion hole 11e of the leg portion 1, and the top plate 2 is placed so that the long screw fits into the screw insertion hole 33 of the mounting bracket 3. Then, a nut can be attached to the long screw through the gap between the top plate 2 and the leg mounting surface 32 of the mounting bracket 3 and fastened. If the gap between the top plate 2 and the mounting bracket is large, a headed long screw can also be inserted through the gap between the top plate 2 and the leg mounting surface 32 of the mounting bracket 3 into the screw insertion hole 33 and fastened.

[0044] [6] Examples of modifications to furniture with legs [6-1] Backrest and assembly method In this embodiment, the legged furniture B is configured as a bench without a backrest, but it can also be configured as a bench with a backrest by forming a backrest on the rear side of the top plate 2. In addition to being a bench, the legged furniture B can also be used as a table, various types of stands, cabinets, etc.

[0045] [6-2] Screw insertion holes for mounting brackets Furthermore, a different assembly method from this embodiment can be adopted. For example, depending on the configuration, the mounting bracket 3 shown in Figure 2(b) can be placed first on the upper surface of each leg 1, which is arranged at predetermined intervals as shown in Figure 2(a), and the mounting bracket 3 and leg 1 can be fastened together with a screw member. In addition, the top plate 2 shown in Figure 2(a) can be placed on the mounting bracket 3 and attached with a screw member, thereby spanning the top plate 2 between the left and right leg 1. [Explanation of symbols]

[0046] 1 leg 11 Upper member 11a Top part 11b Front and rear sides 11c Left and right sides 11d opening 11e Screw insertion hole 11f convex part 11g stepped section 11h Rib 12 Lower part 12a Top part 12b Front and rear sides 12c Left and right sides 12d bottom 12e Nut component 12f guide groove 2 Top plate 21 Board material 22 Connecting fittings 3. Mounting brackets 31 Top panel mounting surface 32 Leg mounting surface 33 Screw insertion holes B Furniture with legs C Clearance

Claims

1. In a piece of furniture with legs, in which a tabletop is attached to legs positioned on both the left and right sides, A piece of furniture with legs, wherein the legs are made of concrete members divided into upper and lower sections, and the upper and lower sections are configured to be integrated by interlocking grooves and protrusions.

2. The legged furniture according to claim 1, wherein the upper leg member has a hollow shape with an opening on the bottom side, and the upper leg member is configured to be placed over the lower leg member and integrated together.

3. The legged furniture according to claim 2, wherein, when the upper leg member is placed over the lower leg member, a clearance in the left-right direction is formed between the inner walls of the lower leg member and the upper leg member.

4. The legged furniture according to claim 2 or 3, wherein vertical ribs are formed on one or both of the left and right inner walls within the hollow portion of the upper leg member, and vertical guide grooves corresponding to the position and shape of the ribs are formed on the lower leg member, so that the ribs can be fitted into the guide grooves.

5. The legged furniture according to claim 2 or 3, wherein, in the connection between the leg and the tabletop, a screw insertion hole is formed on the upper surface side of the upper member of the leg, and the tabletop and the lower member of the leg are connected by passing a screw member through this screw insertion hole.

6. The legged furniture according to claim 5, wherein a protrusion projecting downward on the inner side is formed around the screw insertion hole of the upper leg member, and when the upper leg member is placed over the lower member, the protrusion contacts the upper surface of the lower member.

7. The legged furniture according to claim 2 or 3, wherein the thickness of the left and right wall surfaces of the upper leg member is formed to be thinner on the bottom side and thicker on the top side, and the cross-sectional area of ​​the hollow portion decreases from the bottom side to the top side.

Images