阅读说明：本技术 基于三伸缩杆驱动和准测地线网格结构的反射面天线 (Reflecting surface antenna based on three-telescopic-rod driving and quasi-geodesic grid structure ) 是由 郑飞 颜立德 陈梅 芮喜 于 2020-11-23 设计创作，主要内容包括：本发明提出了一种基于三伸缩杆驱动和准测地线网格结构的反射面天线,旨在在保证反射面天线的型面精度的同时,减轻反射面天线的质量,并降低建造成本。包括支撑背架、反射面骨架、竖向连接杆、主反射面、副反射面、径向支撑杆、馈源和姿态控制装置；所述支撑背架和反射面骨架采用准测地线网格形式的抛物面状桁架结构；所述支撑背架与反射面骨架之间,通过竖向连接杆连接；所述主反射面固定在反射面骨架的准测地线网格上；所述副反射面通过径向支撑杆固定在主反射面的焦点位置；所述馈源固定在反射面骨架的顶点位置；所述姿态控制装置,包括基座和伸缩杆,每根伸缩杆的底端通过转动副连接结构与基座连接,顶端通过球面副连接结构与支撑背架连接。(The invention provides a reflector antenna based on a three-telescopic-rod driving and quasi-geodesic grid structure, aiming at reducing the quality of the reflector antenna and reducing the construction cost while ensuring the profile precision of the reflector antenna. The device comprises a supporting back frame, a reflecting surface framework, a vertical connecting rod, a main reflecting surface, an auxiliary reflecting surface, a radial supporting rod, a feed source and an attitude control device; the supporting back frame and the reflecting surface framework adopt a parabolic truss structure in a quasi-geodesic grid form; the supporting back frame is connected with the reflecting surface framework through a vertical connecting rod; the main reflecting surface is fixed on a quasi-geodesic grid of the reflecting surface framework; the auxiliary reflecting surface is fixed at the focus position of the main reflecting surface through a radial supporting rod; the feed source is fixed at the vertex position of the reflector framework; the posture control device comprises a base and telescopic rods, wherein the bottom end of each telescopic rod is connected with the base through a revolute pair connecting structure, and the top end of each telescopic rod is connected with a support back frame through a spherical pair connecting structure.)

1. The utility model provides a plane of reflection antenna based on three telescopic link drives and accurate geodesic grid structure, its characterized in that, including supporting back of the body frame (1), plane of reflection skeleton (2), vertical connecting rod (3), main reflecting surface (4), subreflector (5), radial bracing piece (6), feed (7) and attitude control device (8), wherein:

the supporting back frame (1) adopts a parabolic truss structure comprising a supporting main back frame (11) and a supporting secondary back frame (12), the supporting main back frame (11) adopts a truss structure formed by connecting a plurality of first main rod pieces and a plurality of first main joint balls, and the supporting main back frame comprises an inner ring frame, an outer ring frame and N radial frames which are distributed between the inner ring frame and the outer ring frame and are radially and uniformly arranged; the supporting secondary back frame (12) comprises N truss structure units in a quasi-geodesic grid form, each truss structure unit is formed by connecting a plurality of first secondary rods and a plurality of first secondary joint balls, each truss structure unit is distributed in a space area formed by the middle inner ring frame, the outer ring frame and the adjacent radial frame of the supporting main back frame (11), the first secondary rods adjacent to the first main joint balls are connected with the first main joint balls, and N is more than or equal to 6;

the reflecting surface skeleton (2) adopts a parabolic truss structure comprising a reflecting surface main skeleton (21) and a reflecting surface secondary skeleton (22), the reflecting surface main skeleton (21) comprises a plurality of second main rod pieces and a plurality of second main joint balls, and the structure and the connection mode of the reflecting surface main skeleton are the same as those of the supporting main back frame (11); the reflecting surface secondary framework (22) comprises N truss structure units in a quasi-geodesic grid form, each truss structure unit is formed by connecting a plurality of second rod pieces and a plurality of second joint balls, the truss structure units are distributed in a space area formed by the middle inner ring framework, the outer ring framework and the adjacent radial frames of the reflecting surface main framework (21), and the second rod pieces adjacent to the second main joint balls are connected with the second main joint balls;

each first main joint ball in the supporting main back frame (11) is connected with a second main joint ball at a corresponding position in the reflecting surface main framework (21), and each first secondary joint ball in the supporting secondary back frame (12) is connected with a second secondary joint ball at a corresponding position in the reflecting surface main framework (21) through a vertical connecting rod (3);

the main reflecting surface (4) comprises a plurality of light metal plates and is fixed on a quasi-geodesic grid of the reflecting surface framework (2);

the shape of the auxiliary reflecting surface (5) is parabolic, the mouth surface of the auxiliary reflecting surface is opposite to the mouth surface of the main reflecting surface (4), and the auxiliary reflecting surface is fixed at the focus position of the main reflecting surface (4) through a radial support rod (6);

the feed source (7) is fixed at the vertex position of the reflecting surface framework (2);

attitude control device (8), including base (81) and three telescopic links (82), the bottom of every telescopic link (82) is connected with base (81) through revolute pair connection structure (83), and the top is connected with support main back of the body frame (11) through spherical pair connection structure (84).

2. The reflector antenna based on the three-telescopic-rod driving and quasi-geodetic-wire grid structure as claimed in claim 1, wherein the first main rod piece, the first sub-rod piece, the second main rod piece and the second sub-rod piece are all hollow carbon fiber tubes, hollow aluminum alloy tubes or hollow steel tubes, the tube diameter of the first main rod piece is larger than that of the first sub-rod piece, the tube diameter of the second main rod piece is larger than that of the second sub-rod piece, the tube diameter of the first main rod piece is larger than that of the second main rod piece, and the tube diameter of the first sub-rod piece is larger than that of the second sub-rod piece; the diameter of the first main joint ball is larger than that of the first secondary joint ball, and the diameter of the second main joint ball is larger than that of the second secondary joint ball.

3. The reflector antenna based on the three telescopic rod driving and geodesic grid structure as claimed in claim 1, wherein the shape of the light metal plate used for the main reflector (4) is triangular or trapezoidal.

4. The reflector antenna based on the three telescopic rod driving and geodesic grid structure as claimed in claim 1, characterized in that said sub-reflector (5) has a focal length equal to that of the main reflector (4), and the focal axis of the sub-reflector (5) coincides with the focal axis of the main reflector (4).

5. The reflector antenna based on the three telescopic rod driving and geodesic grid structure as claimed in claim 1, wherein the attitude control device (8) comprises three revolute pair connection structures (83) which are distributed in an equilateral triangle with the connection point of the base (81), and three spherical pair connection structures (84) which are distributed in an equilateral triangle with the connection point of the supporting main back frame (11).

6. The reflector antenna based on the three telescopic rod driving and ground line grid structure as claimed in claim 1, wherein the vertical connecting rod (3) is a hollow carbon fiber tube, a hollow aluminum alloy tube or a hollow steel tube.

7. The reflector antenna based on the three-telescopic-rod driving and geodesic grid structure as claimed in claim 1, wherein the spherical pair connection structure (84) is a composite spherical hinge structure comprising a hooke hinge and a rotary hinge.

Technical Field

The invention belongs to the technical field of antennas, relates to a reflector antenna, and particularly relates to a reflector antenna based on a three-telescopic-rod driving and quasi-geodesic grid structure.

Background

The reflector antenna is a precise instrument mainly used for receiving electromagnetic radiation, can also radiate electromagnetic waves outwards, can realize large-caliber and narrow-beam, has the characteristics of high resolution and high sensitivity, and is widely applied to the fields of radio astronomy, radar, communication, space detection and the like.

The traditional reflector antenna adopts a solid surface structure made of a rigid panel, the development requirement of communication application is met, the larger the antenna aperture is, the serious deformation is generated due to the influence of factors such as dead weight, temperature, wind load and the like in a complex environment, the precision of the reflector of the antenna is poor, the reflector deviates from the required surface shape, and the adverse effects such as reduction of antenna gain, directional deflection, elevation of a side lobe and the like are caused, so that the wide application of a large-aperture antenna is difficult to realize. To reduce the effects of environmental loads, reflector antennas supported by truss structures have been used. Since the truss structure of the reflector antenna directly affects the weight of the entire antenna, it is necessary to conduct an intensive study on the truss structure of the reflector antenna.

In order to provide a high accuracy, lightweight, easy-to-install reflector antenna of truss structure, like application publication No. CN104362423A, the patent application of the title "double-deck annular truss antenna mechanism of elastic hinge drive", disclose a reflector antenna of double-deck annular truss mechanism, including inner circle annular truss, outer lane annular truss, a plurality of interior outer lane connection trusses and a plurality of cable structure, four corresponding apex angles between inner circle annular truss and the outer lane annular truss are connected the truss through an interior outer lane and are supported. The invention has the defects that the complex truss structure causes complex processing and manufacturing, the weight is high, and the instability of the quadrilateral structure can influence the shape surface precision of the antenna; meanwhile, various truss structures are difficult to process and manufacture, and the forming process is too complex. The technical difficulty of the continuous enlargement of the aperture of the reflecting surface is more and more difficult to overcome due to the restriction of weight and manufacturing difficulty, so that the further popularization and use of the large-aperture antenna are not facilitated.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a reflector antenna based on a three-telescopic-rod driving and quasi-geodesic grid structure, and aims to reduce the quality of the reflector antenna and reduce the construction cost while ensuring the profile precision of the reflector antenna.

In order to achieve the purpose, the technical scheme adopted by the invention comprises a supporting back frame, a reflecting surface framework, a vertical connecting rod, a main reflecting surface, an auxiliary reflecting surface, a radial supporting rod, a feed source and an attitude control device, wherein:

the supporting back frame adopts a parabolic truss structure comprising a supporting main back frame and a supporting secondary back frame, the supporting main back frame adopts a truss structure formed by connecting a plurality of first main rod pieces and a plurality of first main joint balls, and the supporting main back frame comprises an inner ring frame, an outer ring frame and N radial frames which are distributed between the inner ring frame and the outer ring frame and are radially and uniformly arranged; the supporting secondary back frame comprises N truss structure units in a quasi-geodesic grid form, each truss structure unit is formed by connecting a plurality of first rod pieces and a plurality of first joint balls, each truss structure unit is distributed in a space area formed by the inner ring frame, the outer ring frame and the adjacent radial frame in the supporting main back frame, the first rod pieces adjacent to the first main joint balls are connected with the first main joint balls, and N is larger than or equal to 6.

The reflecting surface skeleton adopts a parabolic truss structure comprising a reflecting surface main skeleton and a reflecting surface secondary skeleton, the reflecting surface main skeleton comprises a plurality of second main rod pieces and a plurality of second main joint balls, and the structure and the connection mode of the reflecting surface main skeleton are the same as those of the supporting main back frame; the reflecting surface secondary framework comprises N truss structure units in a quasi-geodesic grid form, each truss structure unit is formed by connecting a plurality of second secondary rods and a plurality of second secondary joint balls, the truss structure units are distributed in a space area formed by the inner ring frame, the outer ring frame and the adjacent radial frames in the reflecting surface main framework, and the second secondary rods adjacent to the second main joint balls are connected with the second main joint balls.

And each first primary joint ball in the support primary back frame is connected with a second primary joint ball at a corresponding position in the reflection surface main framework through a vertical connecting rod, and each first secondary joint ball in the support secondary back frame is connected with a second secondary joint ball at a corresponding position in the reflection surface main framework.

The main reflecting surface comprises a plurality of light metal plates which are fixed on a quasi-geodesic grid of the reflecting surface framework.

The shape of the auxiliary reflecting surface is a paraboloid, the mouth surface of the auxiliary reflecting surface is opposite to the mouth surface of the main reflecting surface, and the auxiliary reflecting surface is fixed at the focus position of the main reflecting surface through a radial supporting rod.

The feed source is fixed at the vertex position of the reflector framework.

The posture control device comprises a base and three telescopic rods, wherein the bottom end of each telescopic rod is connected with the base through a revolute pair connecting structure, and the top end of each telescopic rod is connected with a support main back frame through a spherical pair connecting structure.

According to the reflector antenna based on the three-telescopic-rod driving and quasi-geodesic-line grid structure, the first main rod piece, the first secondary rod piece, the second main rod piece and the second secondary rod piece are all hollow carbon fiber tubes, hollow aluminum alloy tubes or hollow steel tubes, the pipe diameter of the first main rod piece is larger than that of the first secondary rod piece, the pipe diameter of the second main rod piece is larger than that of the second secondary rod piece, the pipe diameter of the first main rod piece is larger than that of the second main rod piece, and the pipe diameter of the first secondary rod piece is larger than that of the second secondary rod piece; the diameter of the first main joint ball is larger than that of the first secondary joint ball, and the diameter of the second main joint ball is larger than that of the second secondary joint ball.

According to the reflector antenna based on the three-telescopic-rod driving and quasi-geodesic-grid structure, the shape of the adopted light metal plate of the main reflector is triangular or trapezoidal.

According to the reflector antenna based on the three-telescopic-rod driving and quasi-geodesic grid structure, the focal length of the auxiliary reflecting surface is equal to that of the main reflecting surface, and the focal axis of the auxiliary reflecting surface is superposed with that of the main reflecting surface.

Above-mentioned reflector antenna based on three telescopic link drives and accurate geodesic grid structure, attitude control device, the three revolute pair connection structure that wherein contains is equilateral triangle with the tie point of base and distributes, and three spherical pair connection structure is equilateral triangle with the tie point that supports main back of the body frame and distributes.

Above-mentioned reflector antenna based on three telescopic link drives and accurate geodesic grid structure, vertical connecting rod adopts hollow carbon fiber pipe, hollow aluminum alloy pipe or hollow steel pipe.

According to the reflector antenna based on the three-telescopic-rod driving and quasi-geodesic-line grid structure, the spherical pair connecting structure adopts a composite spherical hinge structure comprising a Hooke hinge and a rotating hinge.

Compared with the prior art, the invention has the following advantages:

1. because the supporting secondary back frame and the reflecting surface secondary framework both adopt truss structures in the form of the quasi-geodesic grid, the invention has the characteristics of single form, stable structure and symmetrical structure, and can effectively reduce the quality of the antenna while ensuring the shape and surface precision of the antenna.

2. The invention adopts a three-telescopic-rod parallel driving structure to realize the attitude control of the reflecting device, greatly simplifies the supporting structure for tracking and positioning, and has the advantages of high mechanism rigidity, no position error accumulation, simple and convenient control, easy manufacture and low price, thereby obviously reducing the overall quality of the whole reflecting surface antenna structure system, obviously improving the flexibility and being easy to maintain and replace.

3. The main reflecting surface of the invention adopts a centrosymmetric structure formed by splicing a plurality of light metal plates, has regular and simple structural layout and is convenient to manufacture and maintain.

4. In the attitude control device, the spherical pair connecting structure is adopted for connecting the three telescopic rods and the supporting main back frame, so that the problem that the space domain of the traditional pitching azimuth tracker passes through the zenith 'blind cone' is continuous can be solved satisfactorily, and the attitude control of the azimuth pitching of the reflector antenna in different working spaces and the like can be realized conveniently and quickly.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic structural view of a back frame according to the present invention;

FIG. 3 is a schematic structural view of the attitude control device of the present invention;

FIG. 4 is a graph of the results of a static balance simulation of the present invention.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

in example 1, the main reflective surface of this example is a triangular light metal plate.

Referring to fig. 1, the invention comprises a supporting back frame 1, a reflecting surface framework 2, a vertical connecting rod 3, a main reflecting surface 4, an auxiliary reflecting surface 5, a radial supporting rod 6, a feed source 7 and an attitude control device 8, wherein:

the supporting back frame 1 adopts a parabolic truss structure comprising a supporting main back frame 11 and a supporting secondary back frame 12, the supporting main back frame 11 adopts a truss structure formed by connecting a plurality of first main rod pieces and a plurality of first main joint balls, and comprises an inner ring frame, an outer ring frame and N radial frames which are distributed between the inner ring frame and the outer ring frame and are radially and uniformly arranged; the supporting secondary back frame 12 comprises N truss structure units in a quasi-geodesic grid form, each truss structure unit is formed by connecting a plurality of first secondary rod pieces and a plurality of first secondary joint balls, each truss structure unit is distributed in a space area formed by an inner ring frame, an outer ring frame and adjacent radial frames in the supporting main back frame 11, the first secondary rod pieces adjacent to the first main joint balls are connected with the first main joint balls, and N is more than or equal to 6; because the quasi-geodesic grid form adopted by the truss structure units in the secondary support back frame 12 has the characteristics of single form and stable structure, the processing difficulty of the support back frame 1 can be effectively reduced, and the quality of the antenna is effectively reduced while the shape and surface precision of the antenna is ensured.

The reflecting surface skeleton 2 adopts a parabolic truss structure comprising a reflecting surface main skeleton 21 and a reflecting surface secondary skeleton 22, the reflecting surface main skeleton 21 comprises a plurality of second main rod pieces and a plurality of second main joint balls, and the structure and the connection mode of the reflecting surface main skeleton 21 are the same as those of the supporting main back frame 11; the reflecting surface sub-framework 22 comprises N truss structure units in a quasi-geodesic grid form, each truss structure unit is formed by connecting a plurality of second rod pieces and a plurality of second joint balls, each truss structure unit is distributed in a space area formed by an inner ring frame, an outer ring frame and adjacent radial frames in the reflecting surface main framework 21, and the second rod pieces adjacent to the second main joint balls are connected with the second main joint balls. Because the quasi-geodesic grid form adopted by the truss structure units in the reflecting surface sub-framework 22 has the characteristics of single form and stable structure, the processing difficulty of the reflecting surface framework 2 can be effectively reduced, and the quality of the antenna can be effectively reduced while the surface precision of the antenna is ensured.

The first main rod piece, the first secondary rod piece, the second main rod piece and the second secondary rod piece are all hollow steel tubes, the pipe diameter of the first main rod piece is larger than that of the first secondary rod piece, the pipe diameter of the second main rod piece is larger than that of the second secondary rod piece, the pipe diameter of the first main rod piece is larger than that of the second main rod piece, and the pipe diameter of the first secondary rod piece is larger than that of the second secondary rod piece; the diameter of the first main joint ball is larger than that of the first secondary joint ball, and the diameter of the second main joint ball is larger than that of the second secondary joint ball.

And each first main joint ball in the supporting main back frame 11 is connected with a second main joint ball at a corresponding position in the reflecting surface main framework 21, and each first sub joint ball in the supporting sub back frame 12 is connected with a second sub joint ball at a corresponding position in the reflecting surface main framework 21 through a vertical connecting rod 3. The vertical connecting rod 3 is made of a hollow steel pipe.

The main reflecting surface 4 comprises a plurality of light metal plates and is fixed on the quasi-geodetic wire grid of the reflecting surface framework 2; the main reflecting surface 4 is spliced by a triangular panel; the number of the circumferential arrays is the same as the circumferential equal division of the reflecting surfaces, the number of radial layers in each group of circumferential arrays is the same as the number of radial rings of the reflecting surfaces, the number of the triangular panels at the innermost circle in each group of arrays is 3, and the number of the triangular panels at each layer is increased by 2 until the outermost circle.

The shape of the auxiliary reflecting surface 5 is a paraboloid, the mouth surface of the auxiliary reflecting surface is opposite to the mouth surface of the main reflecting surface 4, and the auxiliary reflecting surface is fixed at the focus position of the main reflecting surface 4 through a radial support rod 6; the focal length of the sub-reflecting surface 5 is equal to that of the main reflecting surface 4, and the focal axis of the sub-reflecting surface 5 coincides with that of the main reflecting surface 4.

The feed source 7 is fixed at the vertex position of the reflector framework 2.

The posture control device 8, the structural schematic diagram of which refers to fig. 3, includes a base 81 and three telescopic rods 82, the bottom end of each telescopic rod 82 is connected with the base 81 through a revolute pair connecting structure 83, and the top end is connected with the support main back frame 11 through a spherical pair connecting structure 84; in order to meet the requirement of longer telescopic length, each telescopic rod 82 is required to adopt a structural mode of multi-section combined connection; the connection points of the three revolute pair connection structures 83 and the base 81 are distributed in an equilateral triangle, and the connection points of the three spherical pair connection structures 84 and the support main back frame 11 are distributed in an equilateral triangle; the attitude control device 8 can rapidly realize attitude control such as azimuth pitching and the like of the reflector antenna in different working spaces by accurately adjusting the lengths of the three telescopic rods 82 and the rotating angle of the revolute pair connecting structure 83; the spherical pair connecting structure 84 adopts a composite spherical hinge structure comprising a Hooke hinge and a rotating hinge; the Hooke hinge comprises a U-shaped plate which is symmetrical left and right, and a threaded hole is formed in the U-shaped plate and used for fixing the Hooke hinge on the supporting main back frame 11; the Hooke hinge is connected with a U-shaped plate in the rotating hinge through a cross shaft; the bottom end sleeve of the rotating hinge is connected with the upper ends of three telescopic rods 82. The attitude control device 8 greatly simplifies the tracking and positioning support structure, so that the overall quality of the whole reflector antenna structure system is obviously reduced, the flexibility is obviously improved, and the whole reflector antenna structure system is easy to maintain and replace.

In embodiment 2, the main reflective surface of this embodiment is made of a trapezoidal light metal plate, and the other structure is the same as that of embodiment 1.

The main reflecting surface 4 is composed of a trapezoidal light metal plate; the main reflecting surface 4 is spliced according to the array of concentric circles by taking the vertex of the reflecting surface framework 2 as the center of a circle, the number of the circumferential arrays is the same as the circumferential equal division number of the reflecting surface, the number of the radial layers in each group of the circumferential arrays is the same as the number of the radial rings of the reflecting surface, the number of the trapezoidal panels in each radial layer in each group of the arrays is one of 1, 2 and 4 according to the maximum area limit of the trapezoid, namely when the number of the trapezoidal panels in the radial layer is 1, the maximum area of the trapezoid exceeds the area limit, the number of the trapezoidal panels in the radial layer is 2; when the number of trapezoidal panels in the radial layer is 2 and the maximum area of the trapezoid exceeds the area limit, the number of trapezoidal panels in the radial layer is 4 until the outermost layer.

The technical effects of the invention are further explained by combining simulation experiments as follows:

1. simulation conditions and contents:

the above example was carried out using commercial simulation software ANSYS mechanical APDL 17.1;

the diameter of the reflection system is 120m, the focal diameter ratio is 0.4, the circumferential equal division number of the reflection surface is 6, the radial annular division number of the reflection surface is 15, the outer diameter of a hollow circular tube of a main framework of the reflection surface is 0.137m, the wall thickness is 0.030m, the outer diameter of a hollow circular tube of a secondary framework of the reflection surface is 0.014m, the wall thickness is 0.005m, the outer diameter of a hollow circular tube supporting a main back frame is 0.196m, the wall thickness is 0.047m, the outer diameter of a hollow circular tube supporting a secondary back frame is 0.045m, the wall thickness is 0.014m, the outer diameter of a hollow circular tube of a vertical connecting rod is 0.125m, the wall thickness is 0.016m, the outer diameter of a hollow circular tube of a radial supporting leg is 0. All the rigid rods are made of steel materials, the thickness of the reflecting panel is 0.002m, and a metal aluminum plate is adopted.

The reflector antenna is placed in an upward-looking position, 3 centrosymmetric supporting points are restrained to be connected with the telescopic rod, static balance simulation is carried out on the reflector antenna under the action of gravity, and the result is shown in fig. 4.

2. Simulation measurement result analysis:

as can be seen from fig. 4, the maximum deformation of the reflective system is 0.037 m. The surface density of the reflecting surface is 104.20kg/m²The root mean square error of the absolute position of the node of the reflecting surface is 28.08 mm. On the basis of whichFurther performing shape-keeping design, the precision of the molded surface is 0.82mm, and the surface density in the reference is 407kg/m²And the profile precision is 1.0mm, so that the reflector antenna can effectively reduce the quality of the antenna while ensuring the profile precision of the antenna.

The particular embodiments described above are illustrative of the invention only and are not to be construed as limiting the invention. It will be apparent to those skilled in the art that various modifications and additions may be made to the described embodiments, or substituted in a similar manner, without departing from the spirit of the invention or exceeding the scope thereof as defined in the appended claims. For example, the present example uses terms such as telescoping rods, reflective surface frames, back-up support, vertical connecting rods, etc., but does not exclude the possibility of using other terms. These terms are used merely to more conveniently describe and explain the nature of the present invention and should not be construed as imposing any additional limitations thereon that are within the spirit of the present invention. Such various modifications and changes in form or detail could be made without departing from the principles and arrangements of the present invention and still fall within the scope of the appended claims.