阅读说明：本技术 一种预埋件及其使用方法 (Embedded part and using method thereof ) 是由 李小毅 熊志富 唐雄 唐忠林 唐贤金 于 2021-08-10 设计创作，主要内容包括：本发明提供了一种预埋件,包括依次连接的内锚固段、固连段和外锚固段；内锚固段嵌设于钢筋笼内,内锚固段在钢筋笼轴向上的投影沿钢筋笼的周向延伸,内锚固段与钢筋笼的内壁连接；固连段贯穿钢筋笼的侧壁；外锚固段与钢筋笼的外壁贴合。还提供了上述预埋件的使用方法,包括以下步骤：将内锚固段嵌设在钢筋笼内并将其沿钢筋笼的周向固定在该钢筋笼内侧面；将安装有预埋件的钢筋笼放入桩孔内,进行混凝土浇筑以形成桩基；基坑挖至环框梁高度时,破除桩基混凝土使得外锚固段充分暴露；外锚固段扳直水平状态。本发明通过在桩基中设置预埋件的方式安装环框梁,固定牢靠,施工效率高,并且可大大节省成本。(The invention provides an embedded part, which comprises an inner anchoring section, a fixed connection section and an outer anchoring section which are connected in sequence; the inner anchoring section is embedded in the reinforcement cage, the projection of the inner anchoring section in the axial direction of the reinforcement cage extends along the circumferential direction of the reinforcement cage, and the inner anchoring section is connected with the inner wall of the reinforcement cage; the fixed connection section penetrates through the side wall of the reinforcement cage; the outer anchoring section is attached to the outer wall of the reinforcement cage. The use method of the embedded part is further provided, and the use method comprises the following steps: embedding the inner anchoring section in the reinforcement cage and fixing the inner anchoring section on the inner side surface of the reinforcement cage along the circumferential direction of the reinforcement cage; placing the reinforcement cage provided with the embedded part into the pile hole, and pouring concrete to form a pile foundation; when the foundation pit is dug to the height of the ring frame beam, pile foundation concrete is broken to fully expose the outer anchoring section; the outer anchoring section is straightened to be in a horizontal state. The ring frame beam is installed in the mode that the embedded parts are arranged in the pile foundation, so that the fixing is firm, the construction efficiency is high, and the cost can be greatly saved.)

1. An embedded part, its characterized in that: comprises an inner anchoring section (43), a fixed connection section (42) and an outer anchoring section (41) which are connected in sequence;

the inner anchoring section (43) is embedded in the reinforcement cage (11), the projection of the inner anchoring section (43) in the axial direction of the reinforcement cage (11) extends along the circumferential direction of the reinforcement cage (11), and the inner anchoring section (43) is connected with the inner wall of the reinforcement cage (11);

the fixedly-connected section (42) penetrates through the side wall of the reinforcement cage (11);

the outer anchoring section (41) is attached to the outer wall of the reinforcement cage (11).

2. The embedment of claim 1, wherein: the steel reinforcement cage (11) is cylindrical, and the shape of the inner anchoring section (43) is arc-shaped and extends along the circumferential direction of the steel reinforcement cage (11).

3. The embedment of claim 2, wherein: the circular arc is concentric with the reinforcement cage (11).

4. The embedment of claim 1, wherein: the outer anchoring section (41) is attached to the outer wall of the reinforcement cage (11) in a manner extending axially of the reinforcement cage (11).

5. A method of using an embedment, applied to the embedment of any one of claims 1 to 4, comprising the steps of:

s1, installing an embedded part: embedding the inner anchoring section (43) in the reinforcement cage (11) and fixing the inner anchoring section in the inner side surface of the reinforcement cage (11) along the circumferential direction of the reinforcement cage (11);

s2, embedding an embedded part: placing the reinforcement cage (11) provided with the embedded part into a pile hole, and pouring concrete to form a pile foundation (1);

s3, chiseling out the embedded part: when the foundation pit is dug to the height of the ring frame beam (2), breaking the concrete of the pile foundation (1) to fully expose the outer anchoring section (41);

s4, straightening the embedded part: the outer anchoring section (41) is straightened to be horizontal.

6. The method of using an embedment of claim 5, wherein: the S1 includes the following steps:

A1. marking the installation central point (5) of the embedded part on the outer wall of the reinforcement cage (11) according to the design position of the ring frame beam (2);

A2. the central point (5) is used as the center on the outer wall of the reinforcement cage (11), and the left and right of the central shaft of the reinforcement cage (11) do not exceed 45 degrees to define the installation area of the embedded part;

A3. installing a plurality of embedded parts on the reinforcement cage (11) so that the outer anchoring sections (41) of the embedded parts are positioned in the installation area and attached to the outer wall of the reinforcement cage (11);

A4. and connecting the inner anchoring section (43) with a plurality of main ribs (111) on the circumference of the reinforcement cage (11) in a welding mode.

7. The method of using an embedment of claim 6, wherein: and in the step S2, before concrete pouring, the position of the reinforcement cage (11) is adjusted to enable the central point (5) to be distributed close to one side of the ring frame beam (2).

Technical Field

The invention relates to the technical field of building construction, in particular to an embedded part and a using method thereof.

Background

Urban development is subject to a large land factor, so that the application of underground spaces becomes an important part of current urban construction, and most typical underground space application is the construction of underground rail transit. In the process of excavating the subway track, a vertical shaft needs to be excavated along the track, the supporting structure of the vertical shaft is mostly a structure of a row pile, a crown beam 3 and a ring frame beam 2, and the structure is shown in figure 1. In order to facilitate the construction of the ring frame beam 2 on the pile foundation 1, in the shaft excavation process, the excavation is stopped when the ring frame beam 2 reaches the design height, the pile foundation 1 is chiseled close to the ring frame beam 2 side, so that the reinforcement cage 11 of the pile foundation 1 is exposed, and the connecting assembly is welded on the reinforcement cage 11 and used for fixing the ring frame beam 2.

In the prior art, as shown in fig. 2, the reinforcement cage 11 includes at least a main reinforcement 111, a stirrup 112, and an inner reinforcement 113. When the ring frame beam 2 is constructed according to the method, firstly, the connection points of the ring frame beam 2 and the reinforcement cage 11 of the pile foundation 1 are concentrated on the main ribs 111 of the reinforcement cage 11 close to one side of the ring frame beam 2, namely, the connection strength of the ring frame beam 2 and the pile foundation 1 depends on the main ribs 111, so that the stress of the pile foundation 1 is not uniform on the whole; secondly, in order to ensure the installation quantity of the connecting components, the pile foundation 1 needs to be dug out in a large quantity, so that the strength of the pile foundation 1 is influenced on one hand, and the workload of workers is increased on the other hand; finally, concrete is bonded on the reinforcement cage 11 chiseled at the later stage, and the welding strength of the connecting assembly is affected.

In the prior art, a connecting piece is embedded in a pile foundation in a pre-buried mode, and the embedded piece is fixedly connected with the ring frame beam after the embedded piece is exposed by breaking pile foundation concrete at a later stage. However, due to the design of the embedded part, when the embedded part is fixed with the reinforcement cage, the embedded part is easily interfered with the structure of the reinforcement cage, the embedded part is mainly interfered with the inner reinforcing ribs of the reinforcement cage, the welding difficulty between the embedded part and the reinforcement cage is large, the concrete pouring in the reinforcement cage is influenced, and the connection points of the traditional embedded part and the reinforcement cage are mostly concentrated on the side of the ring frame beam, so that the reinforcement cage is unevenly stressed, and the safety is poor.

In view of this, the present application is specifically made.

Disclosure of Invention

In view of the shortcomings of the prior art, a first object of the present invention is to provide an embedded part, which has a reasonable structure, is convenient for being matched and connected with a reinforcement cage, and is convenient for reliably connecting the reinforcement cage and a ring frame beam into an organic whole.

The second purpose of the invention is to provide a using method of the embedded part, which is used for connecting the reinforcement cage and the ring frame beam in a manner of arranging the embedded part, and has high efficiency, high strength and low cost.

The embodiment of the invention is realized by the following technical scheme:

an embedded part comprises an inner anchoring section, a fixed connection section and an outer anchoring section which are connected in sequence; the inner anchoring section is embedded in the reinforcement cage, the projection of the inner anchoring section in the axial direction of the reinforcement cage extends along the circumferential direction of the reinforcement cage, and the inner anchoring section is connected with the inner wall of the reinforcement cage; the fixed connection section penetrates through the side wall of the reinforcement cage; the outer anchoring section is attached to the outer wall of the reinforcement cage.

According to a preferred embodiment, the reinforcement cage is cylindrical, and the outer shape of the inner anchoring section is arc-shaped extending along the circumferential direction of the reinforcement cage.

According to a preferred embodiment, the circular arc is concentric with the reinforcement cage.

According to a preferred embodiment, the outer anchoring section is attached to the outer wall of the reinforcement cage in a manner extending in the axial direction of the reinforcement cage.

A use method of an embedded part comprises the following steps:

s1, installing an embedded part: embedding the inner anchoring section in a reinforcement cage and fixing the inner anchoring section on the inner side surface of the reinforcement cage along the circumferential direction of the reinforcement cage;

s2, embedding an embedded part: placing the reinforcement cage provided with the embedded part into a pile hole, and pouring concrete to form a pile foundation;

s3, chiseling out the embedded part: when the foundation pit is dug to the height of the ring frame beam, pile foundation concrete is broken to fully expose the outer anchoring section;

s4, straightening the embedded part: and straightening the outer anchoring section to be in a horizontal state.

According to a preferred embodiment, the S1 includes the following steps:

A1. marking the installation central point of the embedded part on the outer wall of the reinforcement cage according to the design position of the ring frame beam;

A2. defining an installation area of the embedded part on the outer wall of the reinforcement cage by taking the central point as a center and not more than 45 degrees around the central axis of the reinforcement cage;

A3. installing a plurality of embedded parts on the reinforcement cage, so that the outer anchoring sections of the embedded parts are positioned in the installation area and attached to the outer wall of the reinforcement cage;

A4. and connecting the inner anchoring section with a plurality of main reinforcements in the circumferential direction of the reinforcement cage in a welding mode.

In a preferred embodiment, in the step S2, the reinforcement cage is positioned so that the center point is located near one side of the ring frame beam before the concrete is poured.

The technical scheme of the embodiment of the invention at least has the following advantages and beneficial effects:

(1) the invention is used for installing the ring frame beam by arranging the embedded part, has simple processing, convenient installation and high utilization rate of subsequent construction, greatly reduces the workload of welders, saves a large amount of welding rods and raw materials of reinforcing steel bars, reduces the construction investment, improves the construction benefit, optimizes the integral stress of the structure, reduces the safety risk of excavation of the foundation pit, and provides a new idea and a new method for the construction of the embedded part of the pile foundation of the deep foundation pit.

(2) The inner anchoring section of the embedded part is used for connecting the embedded part with the reinforcement cage, and the projection of the embedded part in the axial direction of the reinforcement cage extends along the circumferential direction of the reinforcement cage, so that on one hand, the embedded part can be prevented from interfering with the inner reinforcing rib of the reinforcement cage in the fixing process, the embedded part is convenient to install, and on the basis, the inner anchoring section is connected with the main rib in a fitting manner, the influence of the embedded part on the inner space of the reinforcement cage in the horizontal direction can be reduced, and the reinforcement cage can be conveniently subjected to concrete pouring in the subsequent process; on the other hand, the connection points of the inner anchoring sections and the reinforcement cage are dispersed on a plurality of main reinforcements in the circumferential direction of the reinforcement cage, the fixation is firm, stress points of the reinforcement are dispersed and uniform after the embedded parts act when the ring frame beam is constructed, the safety is good, the embedded parts are connected with the main reinforcements and are fixed by concrete poured in the reinforcement cage, and the strength is high.

(3) The outer anchoring section of the embedded part is attached to the outer wall of the reinforcement cage, so that the situation that the inner wall of the pile hole is clamped and fixed in the process of placing the reinforcement cage into the pile hole can be avoided.

(4) The embedded part has strong applicability, is not limited by other components of the reinforcement cage, can be adjusted according to different pile diameters and design requirements, and can be almost used for the cast-in-place pile foundation engineering of all embedded bars.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic front view of a shaft support according to the present invention;

FIG. 2 is a schematic front view of the reinforcement cage of the present invention;

FIG. 3 is a schematic top view of the reinforcement cage of the present invention;

FIG. 4 is a schematic perspective view of an embedded part according to the present invention;

FIG. 5 is a schematic view of an elevational structure of the embedment member and the reinforcement cage in accordance with the present invention;

FIG. 6 is a schematic diagram of a top view of the embedded part and the reinforcement cage in cooperation with each other according to the present invention;

FIG. 7 is a schematic view of a three-dimensional structure of an embedded part and a reinforcement cage in a matched installation manner;

fig. 8 is a schematic perspective view of an embedded part in another form according to the present invention.

Icon: 1-pile foundation, 11-reinforcement cage, 111-main reinforcement, 112-stirrup, 113-inner reinforcement, 2-ring frame beam, 3-crown beam, 41-outer anchoring section, 42-fixed connection section, 43-inner anchoring section, 5-central point, alpha-right included angle and beta-left included angle.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are usually placed in when used, the terms are only used for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements indicated must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be further noted that unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1 to 3, in the supporting structure, a plurality of pile foundations 1 are arranged in parallel to form a row pile, a crown beam 3 for connecting the pile foundations 1 is disposed at the top end of the row pile, and a plurality of ring frame beams 2 for connecting the pile foundations 1 are disposed at intervals in the vertical direction of the row pile. The reinforcement cage 11 at least comprises a frame formed by a plurality of main reinforcements 111 distributed circumferentially, a plurality of stirrups 112 distributed at intervals along the axial direction of the main reinforcements 111 are sleeved on the outer side of the frame, and a plurality of inner reinforcing ribs 113 distributed at intervals along the axial direction of the main reinforcements 111 are arranged in the frame; a plurality of stirrups 112 equidistance equipartition, 113 equidistance equipartition of a plurality of interior strengthening ribs. In view of the defects of the prior art, the problems are overcome by embedding the connecting component.

Referring to fig. 4 to 7, an embedded part includes an inner anchoring section 43, a fixed connection section 42 and an outer anchoring section 41, which are connected in sequence; the inner anchoring section 43 is embedded in the reinforcement cage 11, the projection of the inner anchoring section 43 in the axial direction of the reinforcement cage 11 extends along the circumferential direction of the reinforcement cage 11, and the inner anchoring section 43 is connected with the inner wall of the reinforcement cage 11; the fixed connection section 42 penetrates through the side wall of the reinforcement cage 11; the outer anchoring section 41 is attached to the outer wall of the reinforcement cage 11. The inner anchoring section 43 is used for connecting the embedded part with the reinforcement cage 11, and the projection of the embedded part in the axial direction of the reinforcement cage 11 extends along the circumferential direction of the reinforcement cage 11, so that on one hand, the interference between the embedded part and the inner reinforcing rib 113 of the reinforcement cage 11 in the fixing process of the embedded part can be avoided, the installation of the embedded part is convenient, on the basis, the inner anchoring section 43 is attached and connected with the main rib 111, the influence of the embedded part on the inner space of the reinforcement cage 11 in the horizontal direction can be reduced, and the subsequent concrete pouring of the reinforcement cage 11 is convenient; on the other hand, the connection points of the inner anchoring sections 43 and the reinforcement cage 11 are dispersed on the plurality of main reinforcements 111 in the circumferential direction of the reinforcement cage 11, so that the fixation is firm, when the ring-shaped frame beam 2 is constructed, the stress points of the reinforcements are dispersed and uniform after the embedded parts are acted, the safety is good, and the embedded parts are fixed by concrete poured in the reinforcement cage 11 besides being connected with the main reinforcements 111, so that the strength is high. The outer anchoring section 41 can be prevented from being stuck to the inner wall of the pile hole in the process of putting the steel reinforcement cage 11 into the pile hole after being attached to the outer wall of the steel reinforcement cage 11.

When the embedded part fixing device is used, firstly, the inner anchoring section 43 is fixed inside the reinforcement cage 11 to realize the connection of the embedded part and the reinforcement cage 11, then the embedded part and the reinforcement cage 11 are placed into a pile hole together for pouring, and then in the process of digging a vertical shaft or a foundation pit, when the designed height of the ring frame beam 2 is reached, the outer anchoring section 41 is chiseled out of a pouring body for fixing the ring frame beam 2.

In this embodiment, the reinforcement cage 11 is cylindrical, and the outer shape of the inner anchoring section 43 is arc-shaped extending along the circumferential direction of the reinforcement cage 11. Further, the arc is concentric with the reinforcement cage 11. In the installation process, the inner anchoring section 43 is conveniently and fully attached to a plurality of circumferential main ribs 111 of the reinforcement cage 11, so that the welding of the reinforcement cage and the reinforcement cage 11 by workers is facilitated. In this embodiment, interior anchor section 43 is connected with main muscle 111 with the mode of spot welding, has alleviateed staff's working strength, is favorable to promoting work efficiency.

As shown in fig. 4, the outer anchoring section 41 abuts the outer wall of the reinforcement cage 11 in a manner extending in the axial direction of the reinforcement cage 11. Specifically, as shown in fig. 5, preferably, the inner anchoring section 43 is in a circular arc shape adapted to the axial cross section of the reinforcement cage 11, the fixing section 42 is in a cylindrical shape, wherein an axis line passes through the center of the circular arc contour of the inner anchoring section 43, and the outer anchoring section 41 is in a cylindrical shape, and an axis line thereof is perpendicular to the plane on which the circular arc contour of the inner anchoring section 43 is located. In the subsequent use process, the outer anchoring section 41 chiseled out from the pile foundation 1 needs to be straightened for use. In this embodiment, the inner anchoring section 43, the fixed connection section 42, and the outer anchoring section 41 of the embedded part are integrally formed by bending the steel bar.

It should be noted that the projection profile shape of the inner anchoring section 43 in the axial direction of the reinforcement cage 11 depends on the cross-sectional shape of the reinforcement cage 11 in the axial direction thereof, so as to facilitate the fitting of the inner anchoring section 43 with the reinforcement cage 11. For example, when the cross-sectional shape of the reinforcement cage 11 is rectangular, the projection profile shape of the inner anchoring section 43 in the axial direction of the reinforcement cage 11 is all or a part of the rectangular profile.

As shown in fig. 8, in some embodiments, the inner anchor segment 43 is helical in shape.

The embodiment also provides a use method of the embedded part, which comprises the following steps:

s1, installing an embedded part: embedding the inner anchoring section 43 in the reinforcement cage 11 and fixing the inner anchoring section on the inner side surface of the reinforcement cage 11 along the circumferential direction of the reinforcement cage 11;

s2, embedding an embedded part: placing the reinforcement cage 11 provided with the embedded part into the pile hole, and pouring concrete to form a pile foundation 1;

s3, chiseling out the embedded part: when the foundation pit is dug to the height of the ring frame beam 2, the concrete of the pile foundation 1 is broken to fully expose the outer anchoring section 41;

s4, straightening the embedded part: the outer anchoring section 41 is straightened to be in a horizontal state and extends into the ring frame beam 2, so that the ring frame beam 2 and the pile foundation 1 are connected into a whole.

Specifically, S1 includes the following steps:

A1. marking an installation central point 5 of the embedded part on the outer wall of the reinforcement cage 11 according to the design position of the ring frame beam 2;

A2. the central point 5 is used as the center on the outer wall of the reinforcement cage 11, the left and right sides of the central axis of the reinforcement cage 11 are not more than 45 degrees, the edge lines of the upper and lower ranges are reduced by 10-15cm by the boundary of the ring frame beam 2, and the installation area of the embedded part is defined, specifically as shown in fig. 6, the right included angle alpha and the left included angle beta are not more than 45 degrees;

A3. installing a plurality of embedded parts on the reinforcement cage 11, so that outer anchoring sections 41 of the embedded parts are positioned in an installation area and attached to the outer wall of the reinforcement cage 11;

A4. the inner anchoring section 43 is connected to a plurality of circumferential main reinforcements 111 of the reinforcement cage 11 by welding.

In the above steps, the embedded parts installed on the reinforcement cage 11 are uniformly distributed, and are mainly uniformly distributed in the installation area of the external anchoring section 41, so that the external anchoring section and the ring frame beam 2 can be conveniently installed and fixed in the later period.

In step S2, the reinforcement cage 11 is positioned so that the center point 5 is located closer to the ring frame beam 2 before the concrete is poured. And at this in-process, after steel reinforcement cage 11 transferred the design elevation, adopt to hang the muscle with steel reinforcement cage 11 fixed, avoid it to sink and deflect, guarantee the installation accuracy to when concrete placement, speed should not be too fast, prevent that steel reinforcement cage 11 from taking place the phenomenon of come-up.

Specifically, in the step S3, the pile foundation 1 concrete at the ring frame beam 2 position is broken by using the manual pneumatic pick, so that the outer anchoring section 41 is fully exposed, and water is sprayed in time to reduce dust, thereby avoiding environmental pollution.

In conclusion, the embedded part is arranged for installing the ring frame beam 2, the method is simple to process and convenient to install, the utilization rate of subsequent construction is high, the workload of welders is greatly reduced, the consumption of a large number of welding rods and reinforcing steel bar raw materials is saved, the construction investment is reduced, the construction benefit is improved, the integral stress of the structure is optimized, the safety risk of foundation pit excavation is reduced, and a new idea and a new method are provided for the embedded part construction of the deep foundation pit pile foundation 1; the embedded part has extremely strong applicability, is not limited by other components of the reinforcement cage 11, can be adjusted according to different pile diameters and design requirements, and can be almost used for the engineering of the cast-in-place pile foundation 1 of all embedded bars.

In addition, the invention also provides a processing method of the embedded part, which comprises the following steps:

B1. cutting a steel bar section, marking a first point and a second point in the axial direction of the steel bar section according to a preset size, and dividing the steel bar section into an inner anchoring section 43, a fixed connection section 42 and an outer anchoring section 41 in the axial direction of the steel bar section;

B2. bending the inner anchoring section 43 according to the axial section shape of the corresponding reinforcement cage 11 so that the inner anchoring section can be attached to the inner wall of the reinforcement cage 11 in the circumferential direction;

B3. according to the axial cross-sectional shape of the corresponding reinforcement cage 11, the outer anchoring section 41 is bent so that the inner anchoring section 43 can be attached to the outer wall of the reinforcement cage 11 under the condition that the inner anchoring section is circumferentially attached to the inner wall of the reinforcement cage 11.

Further, in the step B2, the shape of the inner anchoring section 43 is consistent with the axial cross-sectional shape of the reinforcement cage 11.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.