阅读说明：本技术 一种具有降尘机构的轨道交通垫片打磨装置 (Track traffic gasket grinding device with dust fall mechanism ) 是由 沙金洋 李保华 树世轩 张志佳 陆发芹 于 2021-08-24 设计创作，主要内容包括：本发明涉及轨道交通用垫片技术领域,具体为一种具有降尘机构的轨道交通垫片打磨装置,包括打磨台,打磨台的上端中间设置有螺纹转动安装的定位柱,打磨台的上端外缘侧板上端设置有圆环状的转槽,定位柱的外侧套接有工件,定位柱的上端内腔设置有驱动电机驱动的连接杆和竖杆,定位柱与转槽之间设置有横梁；有益效果为：通过设置错位环和竖杆的错位卡接,从而实现便捷快速的位置连接,且配合第二弹簧的复位,使得连接位置固定卡死,大大减小了打磨震动对转动连接造成的影响,提高了打磨过程中连接的稳定性和打磨精度。(The invention relates to the technical field of gaskets for rail transit, in particular to a rail transit gasket polishing device with a dust falling mechanism, which comprises a polishing table, wherein a positioning column which is rotatably installed through threads is arranged in the middle of the upper end of the polishing table, a circular rotating groove is formed in the upper end of a side plate at the outer edge of the upper end of the polishing table, a workpiece is sleeved on the outer side of the positioning column, a connecting rod and a vertical rod which are driven by a driving motor are arranged in an inner cavity of the upper end of the positioning column, and a cross beam is arranged between the positioning column and the rotating groove; the beneficial effects are that: through the dislocation joint that sets up dislocation ring and montant to realize convenient quick position connection, and cooperate the reseing of second spring, make hookup location fixing clip die, reduced greatly and polished the vibrations and to the influence that swivelling joint caused, improved the stability and the precision of polishing in-process connection.)

1. The utility model provides a track traffic gasket grinding device with dust fall mechanism, includes grinding table (1), its characterized in that: a positioning column (6) which is installed in a threaded rotating mode is arranged in the middle of the upper end of the polishing table (1), a circular rotating groove (3) is formed in the upper end of an outer edge side plate of the upper end of the polishing table (1), a workpiece (7) is sleeved on the outer side of the positioning column (6), a connecting rod (23) and a vertical rod (24) which are driven by a driving motor (9) are arranged in an upper end inner cavity of the positioning column (6), a cross beam (13) is arranged between the positioning column (6) and the rotating groove (3), a sleeve (10) fixed to the end portion of the cross beam (13) is sleeved on the vertical rod (24) of the upper end of the positioning column (6), a limiting rotating block (12) fixed to the other end of the cross beam (13) is arranged on the rotating groove (3) in a rotating mode, a polishing motor (14) is arranged on the cross beam (13) in a sliding mode, and a polishing disc (16) which is pressed on the upper end face of the workpiece (7) is connected to the lower end of the polishing motor (14) in a rotating mode, the lower extreme of sleeve (10) is provided with dislocation ring (25), dislocation ring (25) and montant (24) dislocation joint, circular motion is all done through driving motor (9) drive in crossbeam (13), spacing commentaries on classics piece (12) and sleeve (10), the both sides of work piece (7) are provided with extrusion screw (20) extrusion fastening's supporting rod (17).

2. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 1, wherein: the grinding machine is characterized in that a linearly-recessed threaded hole (2) is formed in the middle of the upper end of the grinding table (1), the lower end threads of the positioning column (6) are rotatably installed in the threaded hole (2), the workpiece (7) is sleeved on the outer side of the positioning column (6), and the lower end of the workpiece (7) is pressed on the upper end face of the grinding table (1).

3. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 1, wherein: be provided with guide rail (30) of rectangular recess form on crossbeam (13), grinding motor (14) slidable mounting is in guide rail (30), and the lower extreme of grinding motor (14) is provided with cup joints dust absorption dustcoat (15) in the mill (16) outside, be provided with the suction head in dust absorption dustcoat (15), the external air pump of suction head in dust absorption dustcoat (15).

4. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 1, wherein: the device is characterized in that the driving motor (9) is vertically and fixedly installed in an upper end inner cavity of the positioning column (6) through the cover plate (8), the driving motor (9) is rotated to be connected with the connecting rod (23), the lower end thread of the vertical rod (24) is vertically fixed in an upper end inner cavity of the connecting rod (23), and a lifting sleeve (22) is arranged in an inner cavity of the connecting rod (23).

5. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 4, wherein: a second spring (21) is vertically arranged in an inner cavity of the lower end of the lifting sleeve (22), an upper end circular ring-shaped end plate of the lifting sleeve (22) is pressed on the upper end face of the connecting rod (23), and the second spring (21) is pressed between the end face of the lifting sleeve (22) and the inner wall of the lower end of the inner cavity of the connecting rod (23).

6. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 1, wherein: the vertical grafting of montant (24) is in lift sleeve pipe (22), and montant (24) are located and are provided with four groups of extension blocks (26) that the circumference array distributes on the circular arc outer wall of lift sleeve pipe (22) upper end, sleeve (10) cup joint the upper end outer wall at montant (24), extension block (26) joint is on dislocation ring (25).

7. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 6, wherein: the lower terminal surface pressfitting of dislocation ring (25) is in the upper end of lift sleeve (22), and the position corresponding with extension piece (26) on dislocation ring (25) is provided with vertical groove (27), the upper end of vertical groove (27) extends to the lower terminal surface of sleeve (10), is provided with lateral groove (28) that the circumference extends on the lateral wall of vertical groove (27), the length of lateral groove (28) is the twice of extension piece (26) width, and the tip of lateral groove (28) is provided with draw-in groove (29) of undercut, the width of draw-in groove (29) equals the width of extension piece (26).

8. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 1, wherein: the grinding table is characterized in that a sliding groove (5) is formed in the position, corresponding to the clamping rod (17), of the upper end face of the grinding table (1), a through hole (4) corresponding to the clamping rod (17) is formed in the side wall of the grinding table (1), a sliding block (18) which is slidably mounted in the sliding groove (5) is arranged at the lower end of the clamping rod (17), a fastening arc plate (33) which is pressed on the arc outer wall of a workpiece (7) is arranged at one end of the clamping rod (17), a bearing rod (31) which is slidably inserted into the through hole (4) is arranged at the other end of the clamping rod (17), the bearing rod (31) extends to the outer side of the grinding table (1), and a baffle (32) is arranged at the end of the bearing rod (31).

9. The rail transit pad grinding device with the dust fall mechanism as claimed in claim 8, wherein: the grinding table is characterized in that side frames (11) are arranged on the outer walls of the left side and the right side of the grinding table (1), the baffle (32) is located on the inner side of the side frames (11), extrusion screws (20) which are installed in a rotating mode through transverse threads are arranged on the side frames (11), the end portions of the extrusion screws (20) are pressed on the end faces of the baffle (32), first springs (19) which are sleeved on the outer wall of the pressure bearing rod (31) are transversely arranged on the other side of the baffle (32), and the first springs (19) are pressed between the baffle (32) and the outer wall of the grinding table (1).

Technical Field

The invention relates to the technical field of gaskets for rail transit, in particular to a rail transit gasket grinding device with a dust falling mechanism.

Background

The upper end surface and the lower end surface of the gasket for rail transit need to be polished before use, so that the precision is improved, the friction force generated by connection extrusion is reduced,

however, in the actual polishing process, due to the powder generated by polishing, the machining environment is poor, meanwhile, for gaskets with different inner diameters, the polishing position is difficult to adjust, particularly, the circular gasket is circular, the circular end face of the gasket needs to be circumferentially rotated in the polishing process, when the existing driving device is connected, the gasket is easily connected and falls off or deviates due to the vibration generated by polishing, and therefore the circular rotation dislocation or blockage is caused, and the polishing precision is further influenced.

Therefore, the rail transit gasket grinding device with the dust falling mechanism is provided to solve the problem that grinding vibration affects circumferential rotation.

Disclosure of Invention

The invention aims to provide a rail transit gasket grinding device with a dust falling mechanism, and aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a rail transit gasket polishing device with a dust falling mechanism comprises a polishing platform, wherein a positioning column is arranged in the middle of the upper end of the polishing platform in a threaded rotating mode, a circular rotating groove is formed in the upper end of an outer edge side plate of the upper end of the polishing platform, a workpiece is sleeved on the outer side of the positioning column, a connecting rod and a vertical rod which are driven by a driving motor are arranged in an upper end inner cavity of the positioning column, a cross beam is arranged between the positioning column and the rotating groove, a sleeve which is fixed to the end portion of the cross beam is sleeved on the vertical rod of the upper end of the positioning column, a limiting rotating block which is fixed to the other end of the cross beam is rotatably arranged on the rotating groove, a polishing motor is slidably arranged on the cross beam, a polishing disc which is pressed on the upper end face of the workpiece is rotatably connected to the lower end of the polishing motor, a dislocation ring is arranged at the lower end of the sleeve and is in dislocation clamping connection with the vertical rod, and the cross beam, the limiting rotating block and the sleeve are driven by the driving motor to do circular motion, and clamping rods for extruding and fastening the extruding screws are arranged on two sides of the workpiece.

Preferably, a linear recessed threaded hole is formed in the middle of the upper end of the polishing table, the lower end of the positioning column is rotatably installed in the threaded hole, the workpiece is sleeved on the outer side of the positioning column, and the lower end of the workpiece is pressed on the upper end face of the polishing table.

Preferably, be provided with the guide rail of rectangular recess form on the crossbeam, grinding motor slidable mounting is in the guide rail, and grinding motor's lower extreme is provided with the dust absorption dustcoat of cup jointing in the mill outside, be provided with the suction head in the dust absorption dustcoat, the external air pump of suction head in the dust absorption dustcoat.

Preferably, the driving motor is vertically and fixedly installed in an upper end inner cavity of the positioning column through the cover plate, the driving motor is rotatably connected with the connecting rod, the lower end threads of the vertical rods are rotatably and vertically fixed in an upper end inner cavity of the connecting rod, and the inner cavity of the connecting rod is internally provided with a lifting sleeve.

Preferably, a second spring is vertically arranged in the inner cavity of the lower end of the lifting sleeve, the circular end plate of the upper end of the lifting sleeve is pressed on the upper end face of the connecting rod, and the second spring is pressed between the end face of the lifting sleeve and the inner wall of the lower end of the inner cavity of the connecting rod.

Preferably, the vertical rod is vertically inserted into the lifting sleeve, four groups of extension blocks distributed in a circumferential array are arranged on the arc outer wall of the upper end of the lifting sleeve on the vertical rod, the sleeve is sleeved on the outer wall of the upper end of the vertical rod, and the extension blocks are clamped on the dislocation ring.

Preferably, the lower terminal surface pressfitting of dislocation ring is in lifting sleeve's upper end, and the position that corresponds with the extension piece on the dislocation ring is provided with vertical groove, the upper end in vertical groove extends to telescopic lower terminal surface, is provided with the transverse groove that the circumference extends on the lateral wall in vertical groove, the length of transverse groove is the twice of extension piece width, and the tip in transverse groove is provided with the draw-in groove of undercut, the width of draw-in groove equals the width of extension piece.

Preferably, a sliding groove is formed in the position, corresponding to the clamping rod, of the upper end face of the grinding table, a through hole corresponding to the clamping rod is formed in the side wall of the grinding table, a sliding block is arranged at the lower end of the clamping rod in the sliding groove in a sliding mode, a fastening arc plate pressed on the arc outer wall of the workpiece is arranged at one end of the clamping rod, a pressure-bearing rod inserted into the through hole in a sliding mode is arranged at the other end of the clamping rod, the pressure-bearing rod extends to the outer side of the grinding table, and a baffle is arranged at the end portion of the pressure-bearing rod.

Preferably, side frames are arranged on the outer walls of the left side and the right side of the polishing table, the baffle is located on the inner sides of the side frames, extrusion screws rotatably mounted through transverse threads are arranged on the side frames, the end portions of the extrusion screws are pressed on the end faces of the baffle, a first spring sleeved on the outer wall of the pressure bearing rod is transversely arranged on the other side of the baffle, and the first spring is pressed between the baffle and the outer wall of the polishing table.

Compared with the prior art, the invention has the beneficial effects that:

1. the polishing device is adjusted in position by arranging the transverse beam capable of being adjusted transversely, and the positioning column installed in a threaded manner is matched, so that the positioning column is convenient to replace, the polishing table is adaptive to the processing of gaskets with different inner diameters, and meanwhile, the modular replacement of polishing of the gaskets is realized by utilizing the positioning column with the driving device, so that the efficiency and universality of polishing and processing of the gaskets are greatly improved;

2. according to the invention, the dislocation clamping of the dislocation ring and the vertical rod is arranged, so that convenient and fast position connection is realized, and the connection position is fixedly clamped in cooperation with the resetting of the second spring, so that the influence of polishing vibration on the rotary connection is greatly reduced, and the connection stability and polishing precision in the polishing process are improved.

Drawings

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

FIG. 2 is an enlarged view of the structure at A in FIG. 1;

FIG. 3 is a schematic diagram of a three-dimensional structure of the socket and the vertical rod of the present invention;

FIG. 4 is a schematic view of a staggered clamping three-dimensional structure of a sleeve and a vertical rod of the invention;

FIG. 5 is a schematic perspective view of a beam according to the present invention;

FIG. 6 is a schematic perspective view of the lifting sleeve of the present invention;

FIG. 7 is a perspective view of the clamping rod of the present invention.

In the figure: 1. a polishing table; 2. a threaded hole; 3. rotating the groove; 4. a through hole; 5. a chute; 6. a positioning column; 7. a workpiece; 8. a cover plate; 9. a drive motor; 10. a sleeve; 11. a side frame; 12. a limiting rotating block; 13. a cross beam; 14. polishing the motor; 15. a dust-collecting housing; 16. grinding disc; 17. a clamping rod; 18. a slider; 19. a first spring; 20. extruding the screw; 21. a second spring; 22. a lifting sleeve; 23. a connecting rod; 24. a vertical rod; 25. a dislocation loop; 26. an extension block; 27. a vertical slot; 28. a transverse slot; 29. a card slot; 30. a guide rail; 31. a pressure-bearing rod; 32. a baffle plate; 33. and (5) fastening the arc plate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below. The embodiments of the present invention, and all other embodiments obtained by a person of ordinary skill in the art without any inventive work, belong to the scope of protection of the present invention.

Referring to fig. 1 to 7, the present invention provides a technical solution:

the utility model provides a track traffic gasket grinding device with dust fall mechanism, including grinding platform 1, be provided with the reference column 6 that the screw thread rotated the installation in the middle of grinding platform 1's the upper end, work piece 7 has been cup jointed in the outside of reference column 6, be provided with linear sunken screw hole 2 in the middle of grinding platform 1's the upper end, the lower extreme screw thread of reference column 6 rotates and installs in screw hole 2, work piece 7 cup joints in the outside of reference column 6, the lower extreme pressfitting of work piece 7 is at the up end of grinding platform 1, utilize screw hole 2 to realize the convenient installation of reference column 6, through selecting suitable reference column 6, realize the accurate positioning installation of work piece 7, make grinding platform 1 adaptation in the gasket processing of different internal diameters, utilize the reference column 6 from taking drive arrangement simultaneously, realize the modularization replacement that the gasket polished, thereby the efficiency and the universality of gasket processing of polishing are greatly improved.

The two sides of the workpiece 7 are provided with clamping rods 17 which are tightly extruded by extrusion screws 20, sliding grooves 5 are formed in the positions, corresponding to the clamping rods 17, of the upper end face of the grinding table 1, through holes 4 corresponding to the clamping rods 17 are formed in the side wall of the grinding table 1, sliding blocks 18 which are slidably installed in the sliding grooves 5 are arranged at the lower ends of the clamping rods 17, and transverse sliding installation of the clamping rods 17 is achieved through cooperation of the sliding blocks 18 and the sliding grooves 5.

One end of the clamping rod 17 is provided with a fastening arc plate 33 which is pressed on the arc outer wall of the workpiece 7, the other end of the clamping rod 17 is provided with a pressure-bearing rod 31 which is inserted in the through hole 4 in a sliding manner, the pressure-bearing rod 31 extends to the outer side of the polishing table 1, the end part of the pressure-bearing rod 31 is provided with a baffle plate 32, the outer walls of the left side and the right side of the polishing table 1 are provided with side frames 11, the baffle plate 32 is positioned at the inner side of the side frame 11, the side frame 11 is provided with an extrusion screw rod 20 which is installed in a transverse threaded rotating manner, the end part of the extrusion screw rod 20 is pressed on the end surface of the baffle plate 32, the other side of the baffle plate 32 is transversely provided with a first spring 19 which is sleeved on the outer wall of the pressure-bearing rod 31, the first spring 19 is pressed between the baffle plate 32 and the outer wall of the polishing table 1, the extrusion screw rod 20 is utilized to rotate, so as to realize the extrusion of the baffle plate 32, the pressure-bearing rod 31 and the clamping rod 17, and further to compress the first spring 19, the fastening arc plates 33 at the end parts of the clamping rod 17 which are symmetrical left and right are pressed on the two sides of the workpiece 7, the workpiece 7 is tightly installed, and the position of the pressure bearing rod 31 is limited by the baffle plate 32 and the first spring 19.

The upper end inner chamber of reference column 6 is provided with driving motor 9 driven connecting rod 23 and montant 24, driving motor 9 passes through the vertical fixed mounting of apron 8 in the upper end inner chamber of reference column 6, driving motor 9 rotates and connects connecting rod 23, the lower extreme screw thread of montant 24 rotates and vertically fixes in the upper end inner chamber of connecting rod 23, utilize driving motor 9 to drive connecting rod 23, montant 24, thereby reach and drive 13 circumference pivoted purposes of crossbeam, the realization is to the purpose of the annular gasket work piece 7 fully polishing.

A lifting sleeve 22 is arranged in the inner cavity of the connecting rod 23, a second spring 21 is vertically arranged in the inner cavity of the lower end of the lifting sleeve 22, an annular end plate at the upper end of the lifting sleeve 22 is pressed on the upper end face of the connecting rod 23, the second spring 21 is pressed between the end face of the lifting sleeve 22 and the inner wall of the lower end of the inner cavity of the connecting rod 23, and the second spring 21 is used for realizing vertical lifting installation of the lifting sleeve 22.

The sleeve 10 fixed at the end of the cross beam 13 is sleeved on a vertical rod 24 at the upper end of the positioning column 6, the lower end of the sleeve 10 is provided with a dislocation ring 25, the dislocation ring 25 is in dislocation clamping connection with the vertical rod 24, the vertical rod 24 is vertically inserted into the lifting sleeve 22, four groups of extension blocks 26 distributed in a circumferential array are arranged on the arc outer wall of the upper end of the lifting sleeve 22, the sleeve 10 is sleeved on the outer wall of the upper end of the vertical rod 24, the extension blocks 26 are clamped on the dislocation ring 25, the lower end face of the dislocation ring 25 is pressed at the upper end of the lifting sleeve 22, a vertical groove 27 is arranged at the position, corresponding to the extension blocks 26, on the dislocation ring 25, the upper end of the vertical groove 27 extends to the lower end face of the sleeve 10, in the insertion process of the sleeve 10, the dislocation ring 25 is pressed at the top of the lifting sleeve 22 through the vertical groove 27, and then the second spring 21 is driven to be compressed.

The lateral wall of the vertical groove 27 is provided with a transverse groove 28 extending circumferentially, the length of the transverse groove 28 is twice the width of the extension block 26, the end of the transverse groove 28 is provided with a clamping groove 29 recessed downwards, the width of the clamping groove 29 is equal to the width of the extension block 26, when the second spring 21 is compressed, the lifting sleeve 22 descends, so that the transverse groove 28 is pressed to the position with the same height as the extension block 26, at the moment, the sleeve 10 is rotated, the extension block 26 is rotated to the inner side end part of the transverse groove 28, the extrusion on the sleeve 10 is loosened, under the action of the reset elastic force of the second spring 21, the lifting sleeve 22 ascends, the dislocation ring 25 and the sleeve 10 are driven to ascend, the extension block 26 is dislocated and clamped in the clamping groove 29, the fixing and clamping of the connecting position are realized, the influence of the grinding vibration on the rotary connection is greatly reduced, and the stability and the grinding precision of the connection in the grinding process are improved.

The upper end outer fringe curb plate upper end of platform 1 of polishing is provided with annular rotary tank 3, is provided with crossbeam 13 between reference column 6 and the rotary tank 3, rotates on the rotary tank 3 to be provided with the spacing commentaries on classics piece 12 of fixing at the crossbeam 13 other end, through the cooperation of spacing commentaries on classics piece 12 and rotary tank 3, prescribes a limit to the position of crossbeam 13 outside end to make the circumference of crossbeam 13 rotate more steadily.

Sliding mounting has grinding motor 14 on crossbeam 13, grinding motor 14's lower extreme rotates and is connected with the polishing dish 16 of pressfitting at work piece 7 up end, crossbeam 13, spacing commentaries on classics piece 12 and sleeve 10 all are circular motion through the drive of driving motor 9 drive, be provided with the guide rail 30 of rectangular recess form on crossbeam 13, grinding motor 14 slidable mounting is in guide rail 30, and grinding motor 14's lower extreme is provided with the dust absorption dustcoat 15 of cup jointing in the polishing dish 16 outside, be provided with the suction head in the dust absorption dustcoat 15, the external air pump of suction head in the dust absorption dustcoat 15, the regulation of grinding device position is realized through crossbeam 13 that sets up horizontal adjustment, cooperation dust absorption dustcoat 15 inhales the dust fall to the position of polishing, thereby improved the protection to the environment of polishing.

The working principle is as follows: at first, utilize screw hole 2 to realize the convenient installation of reference column 6, through selecting suitable reference column 6, realize the accurate positioning installation of work piece 7 for 1 adaptation of the platform of polishing is in the gasket processing of different internal diameters, utilizes the reference column 6 from taking drive arrangement simultaneously, realizes the modularization replacement that the gasket was polished, thereby has improved the efficiency and the universality of gasket processing of polishing greatly.

Utilize the cooperation of slider 18 and spout 5, realize the lateral sliding installation of holding rod 17, utilize extrusion screw 20's screw thread to rotate, realize the extrusion to baffle 32, pressure-bearing rod 31 and holding rod 17, and then make first spring 19 compressed, the fastening arc board 33 pressfitting of bilateral symmetry's holding rod 17 tip is in the both sides of work piece 7, realizes the fastening installation of work piece 7, realizes carrying out the position to pressure-bearing rod 31 through baffle 32 and first spring 19 and prescribes a limit to.

The connecting rod 23 and the vertical rod 24 are driven by the driving motor 9, so that the purpose of driving the beam 13 to rotate circumferentially is achieved, and the purpose of fully polishing the circular gasket workpiece 7 is achieved, in the connection process, the second spring 21 is used for achieving vertical lifting installation of the lifting sleeve 22, the dislocation ring 25 is pressed on the top of the lifting sleeve 22 through the vertical groove 27, and further the second spring 21 is driven to be compressed, when the second spring 21 is compressed, the lifting sleeve 22 descends, so that the transverse groove 28 is pressed at the position with the same height as the extension block 26, at the moment, the sleeve 10 is rotated, the extension block 26 is rotated to the inner side end part of the transverse groove 28, the extrusion on the sleeve 10 is released, under the action of the resetting elasticity of the second spring 21, the lifting sleeve 22 ascends, the dislocation ring 25 and the sleeve 10 are driven to ascend in a dislocation manner, the extension block 26 is clamped in the clamping groove 29, so that the fixing of the connection position is fixed, the influence of polishing vibration on the rotary connection is greatly reduced, and the connection stability and polishing precision in the polishing process are improved.

Through the cooperation of spacing commentaries on classics piece 12 and rotary groove 3, inject the position of crossbeam 13 outside end to make the circumference of crossbeam 13 rotate more steadily, but realize the regulation of grinding device position through the crossbeam 13 that sets up transverse regulation, cooperation dust absorption dustcoat 15 is to the dust fall of breathing in of the position of polishing, thereby has improved the protection to the environment of polishing.

The driving motor 9 and the grinding motor 14 are devices commonly used in the art and will not be described in detail.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.