阅读说明：本技术 一种密封可靠的电动推杆 (Electric push rod reliable in sealing ) 是由 何全胜 于 2021-01-26 设计创作，主要内容包括：本发明提供了一种密封可靠的电动推杆,属于电动推杆领域。电动推杆包括分体成型的第一壳体、第二壳体、尾拉和外管,所述第一壳体和所述第二壳体装配后形成穿插所述尾拉的第一装配孔和穿插所述外管的第二装配孔,其特征在于：所述第一壳体和所述第二壳体的交界部位设有密封条,所述密封条包括第一密封条和第二密封条,所述第一装配孔内设有第一密封圈,所述第二装配孔内设有第二密封圈,所述第一密封条、第二密封条、第一密封圈和第二密封圈一体成型并形成闭环结构,本发明的优点在于,采用这种结构,可以使安装人员密封推杆时更加方便,本发明用于电动控制推杆伸缩。(The invention provides an electric push rod with reliable sealing, and belongs to the field of electric push rods. Electric putter draws and the outer tube including components of a whole that can function independently fashioned first casing, second casing, tail, first casing with form the interlude behind the second casing assembly the tail draw first pilot hole with alternate the second pilot hole of outer tube, its characterized in that: the sealing structure has the advantages that due to the adoption of the structure, an installer can seal the push rod more conveniently, and the sealing structure is used for electrically controlling the extension of the push rod.)

1. The utility model provides a sealed reliable electric putter, draws and the outer tube including fashioned first casing of components of a whole that can function independently, second casing, tail, first casing with form after the second casing assembly and alternate the first pilot hole that the tail was drawn and alternate the second pilot hole of outer tube, its characterized in that: the junction position of first casing with the second casing is equipped with the sealing strip, the sealing strip includes first sealing strip and second sealing strip, be equipped with first sealing washer in the first pilot hole, be equipped with the second sealing washer in the second pilot hole, first sealing strip, second sealing strip, first sealing washer and second sealing washer integrated into one piece form and form closed loop structure.

2. A hermetically sealed power putter as claimed in claim 1, wherein: the first sealing strip and the second sealing strip are integrally formed, and in an initial state, the first sealing strip, the second sealing strip, the first sealing ring and the second sealing ring are located on the same plane.

3. A hermetically sealed power putter as claimed in claim 2, wherein: the cross sections of the first sealing strip and the second sealing strip are circular or rectangular.

4. A hermetically sealed power putter as claimed in claim 1, wherein: first sealing strip and/or second sealing strip draw section and outer tube section including the tail of relative separation, the tail is drawn and is fixed connection between section and the outer tube section, first sealing strip, second sealing strip, first sealing washer and second sealing washer pass through the tail draw the section with outer tube section links to each other in order to form closed loop structure.

5. A hermetically sealed power putter as claimed in claim 4, wherein: one of the tail pulling section and the outer pipe section is provided with a convex block, the other one of the tail pulling section and the outer pipe section is provided with a groove, and the convex block is clamped in the groove so as to connect the tail pulling section and the outer pipe section.

6. A hermetically sealed power putter as claimed in claim 5, wherein: the side opening of the groove is smaller than the maximum width of the groove, the lug is matched with the groove, and the lug penetrates through the side opening of the groove.

7. A hermetically sealed electric putter as claimed in any one of claims 1 to 6, further comprising: the first sealing strip and the second sealing strip are provided with positioning protrusions, and the first shell and the second shell are provided with positioning grooves matched with the positioning protrusions.

8. A hermetically sealed electric putter as claimed in any one of claims 1 to 6, further comprising: the first sealing strip with the junction of first sealing washer and second sealing washer forms circular arc transition portion, and/or the second sealing strip with the junction of first sealing washer and second sealing washer forms circular arc transition portion, circular arc transition portion with first casing with second casing interference fit.

9. A hermetically sealed electric putter as claimed in any one of claims 1 to 6, further comprising: the first seal ring has a non-circular cross-section of an inner surface, and the outer tail surface mates with the inner surface of the first seal ring to circumferentially position the first seal ring relative to the tail.

10. A hermetically sealed electric putter as claimed in any one of claims 1 to 6, further comprising: and the second sealing ring is provided with a limiting bulge, and the outer tube is provided with a limiting groove matched with the limiting bulge.

[ technical field ] A method for producing a semiconductor device

The invention relates to an electric push rod with reliable sealing, and belongs to the field of electric push rods.

[ background of the invention ]

At present, electric putter is more and more extensive in the house, field applications such as medical treatment, generally, electric putter is including being used for the encapsulation motor, the push rod shell of parts such as gear assembly, it is more convenient in order to make push rod shell production and processing, the push rod shell divide into first casing and second casing generally and processes and install, and need set up the hole on the push rod shell usually so that the part in the push rod shell can stretch out, in order to improve the leakproofness of push rod, be equipped with the sealing strip between first casing and the second casing, downthehole sealing washer that is equipped with.

Usually, sealing strip and sealing washer are two parts of relative separation, and the back is installed to the push rod, can have the clearance between sealing strip and the sealing washer, need pack glue in the clearance this moment in order to realize fully sealed, but, the volume of filling glue is wayward, and glue has lacked can influence sealedly, and glue has had more can spill over and influence the outward appearance, and is inconvenient when leading to the installer to seal up the push rod.

[ summary of the invention ]

The invention aims to solve the technical problem of providing the electric push rod with reliable sealing, so that an installer can more conveniently seal the push rod.

In order to solve the technical problem, the electric push rod with reliable sealing comprises a first shell, a second shell, a tail pull and an outer tube which are formed in a split mode, a first assembly hole penetrating the tail pull and a second assembly hole penetrating the outer tube are formed after the first shell and the second shell are assembled, a sealing strip is arranged at the junction of the first shell and the second shell and comprises a first sealing strip and a second sealing strip, a first sealing ring is arranged in the first assembly hole, a second sealing ring is arranged in the second assembly hole, and the first sealing strip, the second sealing strip, the first sealing ring and the second sealing ring are formed in an integrated mode to form a closed-loop structure.

Preferably, the first sealing strip and the second sealing strip are integrally formed, and in an initial state, the first sealing strip, the second sealing strip, the first sealing ring and the second sealing ring are located on the same plane.

Preferably, the first sealing strip and the second sealing strip have a circular or rectangular cross section.

Preferably, the first sealing strip and/or the second sealing strip comprise a tail pulling section and an outer pipe section which are separated relatively, the tail pulling section is fixedly connected with the outer pipe section, and the first sealing strip, the second sealing strip, the first sealing ring and the second sealing ring are connected with the outer pipe section through the tail pulling section to form a closed-loop structure.

Preferably, one of the tail pulling section and the outer pipe section is provided with a convex block, the other is provided with a groove, and the convex block is clamped in the groove so as to connect the tail pulling section and the outer pipe section.

Preferably, the groove is open at the side and the opening width is smaller than the maximum width of the groove, the bump is matched with the groove, and the bump penetrates through the side opening of the groove.

Preferably, the first sealing strip and the second sealing strip are provided with positioning protrusions, and the first shell and the second shell are provided with positioning grooves matched with the positioning protrusions.

Preferably, the first sealing strip and the joint of the first sealing ring and the second sealing ring form an arc transition portion, and/or the second sealing strip and the joint of the first sealing ring and the second sealing ring form an arc transition portion, and the arc transition portion is in interference fit with the first shell and the second shell.

Preferably, the first seal ring has a non-circular cross-section of its inner surface, and the outer tail surface mates with the inner surface of the first seal ring to circumferentially locate the first seal ring relative to the tail.

Preferably, the second sealing ring is provided with a limiting protrusion, and the outer tube is provided with a limiting groove matched with the limiting protrusion.

The invention has the beneficial effects that:

firstly, the first sealing strip, the second sealing strip, the first sealing ring and the second sealing ring are integrally formed, so that a gap for sealing glue does not exist between the first sealing strip and the first sealing strip as well as between the first sealing strip and the second sealing strip as well as between the sealing strip and the second sealing ring, and accordingly, an installer does not need to seal by using glue, and further, the push rod is more convenient to seal by the installer, and the sealing effect is better, while in the prior art, after the push rod is sealed by using glue, the first shell and the second shell are fixed by the glue, so that the disassembly and the assembly are inconvenient, the original effect of the glue is lost after the disassembly, when the first shell and the second shell are required to be opened for maintenance and inspection, the glue is inconvenient to open and needs to be filled again when the glue is required to be connected, make the push rod maintenance inspection inconvenient, and do not adopt glue to seal in this scheme, can make the push rod have good maintainability and verifiability for it is more convenient when the staff maintains the inspection to the push rod.

First sealing washer and second sealing washer all are closed annular sealing washer, can be completely sealed with pilot hole circumference through the sealing washer, for closing into a whole when prior art adopts two detached semi-circular sealing member to install and seal up, when adopting the sealing washer in this scheme, the sealing washer is closed annular, and sealed effect can be better, and first sealing washer, second sealing washer, first sealing washer and second sealing washer are closed loop structure and can make sealing washer and sealing washer in the whole continuous no disconnection clearance to further improve the leakproofness of push rod.

These features and advantages of the present invention will be disclosed in more detail in the following detailed description and the accompanying drawings.

[ description of the drawings ]

The invention is described in further detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a schematic view of an electric putter according to an embodiment;

FIG. 2 is a schematic view of a seal and a seal ring according to one embodiment;

FIG. 3 is a three-dimensional schematic view of a seal and a gasket according to one embodiment;

FIG. 4 is an enlarged schematic view of FIG. 3 at G;

FIG. 5 is a schematic view of the tail pull and outer tube of the first embodiment;

FIG. 6 is an enlarged schematic view of FIG. 5 at D;

FIG. 7 is a schematic view of a second housing according to the first embodiment;

FIG. 8 is an enlarged schematic view at E of FIG. 7;

fig. 9 is an enlarged schematic view at F of fig. 7.

FIG. 10 is a schematic view of a seal and a seal ring according to a second embodiment;

FIG. 11 is an enlarged schematic view of FIG. 10 at A;

FIG. 12 is an enlarged schematic view at B of FIG. 10;

FIG. 13 is an enlarged schematic view of FIG. 10 at C;

FIG. 14 is a schematic view of the seal and gasket of the second embodiment after deployment.

Reference numerals:

the sealing structure comprises a first shell, a second shell, a first assembling hole, a second assembling hole, a first sealing strip, a second sealing strip, a first sealing ring, a second sealing ring, a first sealing ring, a second sealing ring, a 9 outer pipe, a tail pull, a limiting groove, a 12 outer pipe section, a tail pull section, a convex block, a 15 positioning protrusion, a limiting protrusion, a 17 arc transition part, a convex block clamping groove, and a 19 positioning groove, wherein the first shell is 1, the second shell is 2, the first assembling hole is 3, the second assembling hole is 4.

[ detailed description ] embodiments

The technical solutions of the embodiments of the present invention are explained and illustrated below with reference to the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, and not all embodiments. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present invention.

In the following description, the terms such as "inner", "outer", "upper", "lower", "left", "right", etc., which indicate orientations or positional relationships, are used to indicate orientations or positional relationships based on the drawings, and are only used for convenience in describing embodiments and for simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present invention.

The first embodiment is as follows:

as shown in fig. 1 to 9, the preferred structure of the reliable sealed electric putter of this embodiment includes that the fashioned first casing 1 of components of a whole that can function independently, second casing 2, tail draw 10 and outer tube 9, first casing 1 with form the interlude after the assembly of second casing 2 the tail draws first pilot hole 3 of 10 and interlude the second pilot hole 4 of outer tube 9, first casing 1 with the juncture of second casing 2 is equipped with the sealing strip, the sealing strip includes first sealing strip 5 and second sealing strip 6, be equipped with first sealing washer 7 in the first pilot hole 3, be equipped with second sealing washer 8 in the second pilot hole 4, first sealing strip 5, second sealing strip 6, first sealing washer 7 and second sealing washer 8 integrated into one piece and form closed loop structure.

The invention has the beneficial effects that:

firstly, the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 are integrally formed, so that a gap for sealing glue does not exist between the first sealing strip 5 and the first sealing strip 6 and between the first sealing strip 5 and the second sealing strip 6 and between the second sealing strip 8, and the sealing strips and the sealing rings, so that an installer does not need to use glue for sealing, and the installer is more convenient to seal the push rod, and has better sealing effect, after the glue is used for sealing in the prior art, the first shell 1 and the second shell 2 can be fixed by the glue, so that the disassembly and the assembly are inconvenient, the glue loses the original effect after the disassembly, when the first shell 1 and the second shell 2 need to be opened for maintenance and inspection, the glue is inconvenient to open and needs to be filled again when the glue is re-assembled, make the push rod maintenance inspection inconvenient, and do not adopt glue to seal in this scheme, can make the push rod have good maintainability and verifiability for it is more convenient when the staff maintains the inspection to the push rod.

First sealing washer 7 and second sealing washer 8 all are closed annular sealing washer, can be completely sealed with pilot hole circumference through the sealing washer, for closing into a whole when prior art adopts two detached semi-circular sealing member to install and seal up, when adopting the sealing washer in this scheme, the sealing washer is closed annular, and sealed effect can be better, and first sealing washer 5, second sealing washer 6, first sealing washer 7 and second sealing washer 8 can make sealing washer and sealing washer whole internal continuous no disconnection clearance for closed loop structure to further improve the leakproofness of push rod.

Usually, first casing 1 and second casing 2 form behind the cavity, the front end need set up second pilot hole 4 so that the outer tube 9, parts such as lead screw stretch out, the rear end need set up first pilot hole 3 so that parts such as tail pull 10 stretch out so that the push rod tail end can link to each other with external device more conveniently, at this moment, when first pilot hole 3 and second pilot hole 4 all were equipped with the sealing washer, an solitary sealing strip can't make whole closed, need set up two sealing strips so that first sealing strip 5 promptly, first sealing washer 7, second sealing strip 6 and 8 end to end formation closed loop construction of second sealing washer, thereby can make the sealed effect that outer tube 9 and tail pull 10 departments better, and then make the sealed effect of push rod better.

The first housing 1 and the second housing 2 may also be provided with a fitting hole for inserting another component protruding from the inside of the cavity formed by the first housing 1 and the second housing 2, for example, a fitting hole for inserting a travel switch is provided.

In addition, the sealing strip and the sealing ring are integrally formed to form a closed loop structure, so that parts can be reduced, and the cost is reduced.

In order to make the integrated post-processing of the sealing strip and the sealing ring more convenient, the embodiment is preferred that the first sealing strip 5 and the second sealing strip 6 are all integrated, and in the initial state, the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 are located on the same plane, and the initial state is the state after the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 are processed and formed, and generally, the plane where the first assembling hole 3 and the second assembling hole 4 are located and the interface between the first shell 1 and the second shell 2 are located on different planes, so that the assembled sealing strip 5 and the assembled second sealing strip 6 and the first sealing ring 7 and the assembled second sealing ring 8 are not located on the same plane and are in a spatial state, and if the installation space state is processed, an inclined plane, a tilted plane, The first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 can be directly used as plane parts for demoulding and can realize demoulding without arranging a sliding block and an inclined plane when the structure is adopted, so that the mould can be simplified, the mould cost can be reduced, the production can be simplified, the parts can be taken easily, the structure can also be suitable for moulds used on a flat vulcanizing machine with a larger proportion in the production, and when the structure is installed, the first sealing ring 7 and the second sealing ring 8 can be rotated, so that the rotated first sealing ring 7 and the rotated second sealing ring 8 can be installed in the first assembling hole 3 and the second assembling hole 4, the first sealing strip 5 and the second sealing strip 6 rotate along with the rotation of the first sealing strip 7 and the second sealing strip 8, and the rotated first sealing strip 7 and the rotated second sealing strip 8 are installed between the first shell 1 and the second shell 2.

In order to further optimize the structure, the cross section of the first sealing strip 5 and the second sealing strip 6 is preferably circular or rectangular, when the sealing strip is installed, the first sealing strip 7 and the second sealing strip 8 need to be rotated 90 degrees to be installed on the first assembly hole 3 and the second assembly hole 4, at this time, if the first sealing strip 5 and the second sealing strip 6 are not rotated as a whole, the first sealing strip 7 and the second sealing strip 8 are twisted due to the rotation of the first sealing strip 7 and the second sealing strip 8, so that the sealing effect is deteriorated, the first sealing strip 5 and the second sealing strip 6 need to be rotated 90 degrees as a whole, as long as the first sealing strip 5 and the second sealing strip 6 rotated 90 degrees can be installed in the installation groove between the first housing 1 and the second housing 2 for sealing, and when the cross section of the first sealing strip 6 and the second sealing strip 6 is circular, the first sealing strip 5 and the second sealing strip 6 are rotated no matter how many degrees as a whole, the diameter of the sealing strip is not changed, the sealing strip can still be installed between the first shell 1 and the second shell 2 without twisting, so that the first sealing strip 5 and the second sealing strip 6 can rotate without changing the shape, when the cross sections of the first sealing strip 6 and the second sealing strip 6 are rectangular, the first sealing strip 5 and the second sealing strip 6 are integrally rotated for 90 degrees and then are matched with the installation groove between the first shell 1 and the second shell 2, and the width of the injection molding groove is ensured to be consistent with the width of the installation groove during injection molding, so that the sealing strip can be processed according to the plane state that the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 are positioned on the same plane during processing, the sealing strip can be processed and used as a whole, the processing is very convenient, the sealing strip can be rotated for 90 degrees during installation, the sealing strip can not be changed due to rotation, and the electric push rod can also have good sealing, the rectangle is preferably square, so that the shape of the first sealing strip 5 and the second sealing strip 6 is not changed after the whole is turned by 90 degrees.

In order to enable the sealing strip to be positioned, it is preferable in this embodiment that the first sealing strip 5 and the second sealing strip 6 are provided with positioning protrusions 15, the first casing 1 and the second casing 2 are provided with positioning grooves 19 matched with the positioning protrusions 15, and the sealing strip can be positioned relative to the first casing 1 or the second casing 2 in a manner that the positioning protrusions 15 are engaged with the positioning grooves 19, so as to facilitate the installation and positioning of the sealing strip.

In order to optimize the structure of the connecting portion between the sealing member and the sealing ring, the embodiment is preferred that the first sealing strip 5 and the joint of the first sealing ring 7 and the second sealing ring 8 form an arc transition portion 17, and/or the second sealing strip 6 and the joint of the first sealing ring 7 and the second sealing ring 8 form an arc transition portion 17, the arc transition portion 17 and the first shell 1 and the second shell 2 are in interference fit, and through the arc transition portion 17, glue at the joint of the split type sealing member can be replaced, so that the process consistency is better, and the disassembly and assembly can be repeated, so that the maintainability is improved, meanwhile, the thickness of the connecting portion can be increased, and the sealing effect can be improved by the interference fit with the first shell 1 and the second shell 2.

In order to optimize the structure of the first seal ring 7, in this embodiment, it is preferable that the cross section of the inner surface of the first seal ring 7 is non-circular, the outer surface of the tail 10 matches with the inner surface of the first seal ring 7 to circumferentially position the first seal ring 7 relative to the tail 10, the circumferential positioning can be realized by the non-circular structure, and meanwhile, in order to circumferentially position the first seal ring 7 on the tail 10, a step can be provided on the tail 10 to limit the movement of the first seal ring 7.

In order to enable the second sealing ring 8 to be positioned, in this embodiment, it is preferable that the second sealing ring 8 is provided with a limiting protrusion 16, the outer tube 9 is provided with a limiting groove 11 matched with the limiting protrusion 16, the second sealing ring 8 can be positioned relative to the outer tube 9 by engaging the limiting protrusion 16 with the limiting groove 11, and meanwhile, the limiting groove 11 can be an elongated slot so as to facilitate the installation of the second sealing ring 8 and facilitate the position adjustment of the outer tube 9.

Example two:

the difference between this embodiment and the first embodiment is that, as shown in fig. 10 to 14, in this embodiment, in order to facilitate the production and processing of the closed-loop structure formed by the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8, in this embodiment, preferably, the first sealing strip 5 and/or the second sealing strip 6 includes a tail section 13 and an outer pipe section 12 which are separated from each other, the tail section 13 and the outer pipe section 12 are fixedly connected, the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 are connected to form the closed-loop structure by the tail section 13 and the outer pipe section 12, because the closed-loop structure formed by the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 is a three-dimensional structure, during demolding needs to use a slope, a slider or other component to assist demolding, which causes inconvenience, the tail pulling section 13 and the outer pipe section 12 can be connected to ensure that the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 are in a closed loop structure, so that the sealing device has good sealing effect, when in production and processing, the tail pulling section 13 and the outer pipe section 12 can be separated, the closed loop structure can be unfolded, the first sealing strip 5, the second sealing strip 6, the first sealing ring 7 and the second sealing ring 8 can be directly used as plane parts for demoulding, and demoulding can be realized without arranging a slide block and an inclined plane, the mode can realize mould simplification, reduce mould cost, simplify production and facilitate taking of parts, and can also be suitable for moulds used on a flat vulcanizing machine with a larger proportion in production, the present embodiment can also achieve the technical effects described in the first embodiment.

In order to make the connection between the tail pulling section 13 and the outer pipe section 12 more stable, in this embodiment, it is preferable that one of the tail pulling section 13 and the outer pipe section 12 is provided with a convex block 14, and the other is provided with a groove, the convex block 14 is clamped into the groove to connect the tail pulling section 13 with the outer pipe section 12, the tail pulling section 13 and the outer pipe section 12 can be connected in a manner of overlapping the convex block 14 and the groove, meanwhile, the convex block 14 can be in interference fit with the groove to more stably fix the convex block 14 in the groove, reduce the gap and improve the sealing effect, the groove can be a closed ring groove, the convex block 14 can be inserted into the ring groove along the axis direction of the ring groove, the side of the groove can also be open, generally, the sealing strip has a smaller volume, and needs to extend a convex block with a larger volume and then process the convex block 14 or the groove on the convex block 14 and the groove to make the connection between the outer, at this time, the first casing 1 or/and the second casing 2 may be provided with a protrusion engaging groove 18 for placing the protrusion 14 and the groove, so that the weather strip may be stably mounted between the first casing 1 and the second casing 2.

In order to optimize the structure of the groove and the bump 14, in this embodiment, it is preferable that the side opening of the groove is smaller than the maximum width of the groove, the bump 14 is matched with the groove, and the bump 14 passes through the side opening of the groove, the side of the groove means that in this embodiment, the groove on the outer pipe section 12 is opened at one side close to the tail pulling section 13, so that the protrusion can be clamped into the groove, and the connection portion between the protrusion and the tail pulling section 13 can extend from the side opening of the groove, when the side of the groove is closed, the portion where the protrusion is clamped into the groove needs to extend from the insertion direction to be connected with the tail pulling section 13, so that the outer pipe section 12 and the tail pulling section 13 are staggered and cannot form the same line, in the scheme of this embodiment, the protrusion can extend from the side opening of the groove to be connected with the tail pulling section 13, so that the outer pipe section 12 and, the sealing effect and the aesthetic degree are improved, secondly, the shape of the groove is indefinite, the groove can be an arc-shaped groove and can also be various shapes such as a dovetail groove, a T-shaped groove and an inclined plane, the width of the side opening of the groove is ensured to be smaller than the maximum width of the groove, the convex block 14 can be limited through the side surface of the groove, the maximum width of the groove is along the direction parallel to the width direction of the side opening of the groove, and the maximum distance between the two inner surfaces of the groove is increased.

While the invention has been described with reference to specific embodiments thereof, it will be understood by those skilled in the art that the invention is not limited thereto, and may be embodied in many different forms without departing from the spirit and scope of the invention as set forth in the following claims. Any modification which does not depart from the functional and structural principles of the present invention is intended to be included within the scope of the claims.