阅读说明：本技术 一种齿科用铸瓷炉多冲杆压铸装置 (Multi-plunger die-casting device of porcelain casting furnace for dentistry ) 是由 王江涛 李东辉 孟烨 柴飞龙 陈雅芳 王亚珂 杨亚超 于 2020-08-11 设计创作，主要内容包括：本发明属于口腔义齿技工修复设备领域,尤其涉及一种齿科用铸瓷炉多冲杆压铸装置。涉及的一种齿科用铸瓷炉多冲杆压铸装置具有顶部、底部开口的炉膛；炉膛的底部开口由炉膛底板封闭；炉膛内放置有炉芯；炉芯为顶部、底部开口的结构；所述炉芯的顶部与炉膛内内衬顶板接触；炉芯内设置有待铸件砂型；待铸件砂型设置在炉门的顶部；待铸件砂型内具有型腔；型腔的顶部具有多个与其连通的压铸孔,并在每个压铸孔内放置热压铸瓷块；每个热压铸磁块顶部放置有冲杆；所述冲杆的顶部与炉膛内所述内衬顶板的底面之间具有用以冲杆上升的空间；炉门为可相对炉膛升降的结构。本发明具有操作简单、方便,压铸精度高的特点。(The invention belongs to the field of dental denture repair equipment, and particularly relates to a dental ceramic furnace multi-plunger die-casting device. The multi-plunger die casting device of the dental porcelain casting furnace comprises a hearth with openings at the top and the bottom; the bottom opening of the hearth is sealed by a hearth bottom plate; a furnace core is arranged in the hearth; the furnace core is of a structure with openings at the top and the bottom; the top of the furnace core is contacted with the top plate of the inner lining of the hearth; a sand mold to be cast is arranged in the furnace core; the sand mould of the casting to be cast is arranged at the top of the furnace door; a cavity is arranged in a sand mold of a to-be-cast part; the top of the cavity is provided with a plurality of die-casting holes communicated with the cavity, and a hot-press casting ceramic block is placed in each die-casting hole; a punch is arranged at the top of each hot-press casting magnetic block; a space for the punch to ascend is formed between the top of the punch and the bottom surface of the lining top plate in the hearth; the furnace door is a structure which can lift relative to the hearth. The invention has the characteristics of simple and convenient operation and high die-casting precision.)

1. The utility model provides a many punches die-casting device of porcelain furnace for dentistry which characterized in that: the die-casting device is provided with a hearth which is of a structure with openings at the top and the bottom; the bottom opening of the hearth is sealed by a hearth bottom plate; a furnace core is arranged in the hearth; the furnace core is of a structure with openings at the top and the bottom; the top of the furnace core is contacted with the top plate of the inner lining of the hearth; a workpiece sand mold to be cast is arranged in the furnace core; the sand mould of the workpiece to be cast is arranged at the top of the furnace door; a mold cavity is arranged in the sand mold of the workpiece to be cast; the top of the cavity is provided with a plurality of die-casting holes communicated with the cavity, and a hot-press casting ceramic block is placed in each die-casting hole; a punch is arranged at the top of each hot-press cast ceramic block; the top of the punch rod protrudes out of the top surface of the sand mold and is lower than the top surface of the furnace core, namely a space for the punch rod to ascend is formed between the top of the punch rod and the bottom surface of the lining top plate in the hearth; the furnace door is of a structure capable of lifting relative to the hearth, the furnace door acts relative to the hearth, and when the plunger rod is in contact with the bottom surface of the lining top plate, die casting is carried out by utilizing acting force between the lining top plate and the plunger rod.

2. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: a driving mechanism which is used for driving the furnace door and a workpiece sand mold to be cast to lift in the furnace core is arranged corresponding to the furnace door; the driving mechanism is provided with an inner tray for supporting the oven door; the furnace door is made of heat insulating materials and separates a high-temperature area of the hearth from the inner tray; the inner tray is connected with the power part through a push rod arranged at the bottom of the outer side of the hearth, the push rod pushes the inner tray, the furnace door, the sand mold and the punch to move upwards under the action of the power part, and when the punch moves upwards and contacts with the bottom surface of the lining top plate, the lining top plate is used for preventing the reaction force of the punch moving upwards to perform die casting.

3. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: a motor for driving the hearth to lift is arranged corresponding to the hearth; the hearth descends to enable the hearth bottom plate to be hermetically connected with the outer tray when the hearth descends.

4. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: the hearth comprises a shell and a lining; the shell is provided with a hearth shell which is of a frame structure and has openings at the upper end and the lower end; the top and the bottom of the hearth shell are respectively sealed by a hearth top plate and a hearth bottom plate; the hearth bottom plate is provided with a through hole for a furnace door to pass through; the hearth is a structure which can be lifted under the action of a hearth lifting motor; the hearth bottom plate and the outer tray are hermetically connected with the outer tray when the hearth descends; the lining is provided with hearth linings positioned on the left side and the right side of the furnace core and lining top plates; the hearth linings on the left side and the right side and the lining top plate form a hearth lining with an opening at the lower end.

5. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: the shell of the hearth is provided with an air exhaust hole, and the air exhaust hole is communicated with a vacuum extractor to provide a high-temperature and vacuum environment for casting the cast porcelain teeth.

6. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: and a ceramic plate is arranged between the lining top plate and the furnace core.

7. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: and a heating body is arranged in the furnace core.

8. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: the power part is provided with a power element used for providing ascending or descending for the push rod; a screw rod of the power element is provided with a guide rod nut flange; the guide rod nut flange is fixedly connected with the transmission flange, a pressure sensor is installed between the transmission flange and the push rod, the power element transmits force to the push rod through the transmission flange, the push rod pushes the inner tray to lift, and the speed and the value of the force applied by the power device are adjusted through the pressure value obtained by the pressure sensor, so that the die-casting effect of the workpiece is guaranteed.

9. The multi-ram die-casting device of the porcelain furnace for dentistry as claimed in claim 1, wherein: a guide mechanism is arranged corresponding to the push rod; the guide mechanism comprises a guide rod upper support and a guide rod lower support; the guide rod upper support is fixedly arranged on the tray base; a plurality of guide rods are arranged between the guide rod upper support and the guide rod lower support, guide sleeves are sleeved on the guide rods and connected with the transmission flange through guide rod connecting pieces, so that the motion direction of the push rod is ensured to be parallel to the guide rods; the tray base is fixedly connected with the base through the left support and the right support.

10. The dental porcelain casting furnace multi-ram die casting device according to claim 8, wherein: the power element is a motor or an air cylinder or an electric push rod which can rotate forward and backward.

Technical Field

The invention belongs to the field of dental denture repair equipment, and particularly relates to a dental ceramic furnace multi-plunger die-casting device.

Background

With the development of technology, the application of cast porcelain teeth in the field of dental restoration is becoming more and more extensive, and the cast porcelain teeth are also called as cast ceramic full crowns and are made of castable ceramic materials. Different from the traditional metal porcelain teeth, the color of the cast porcelain teeth is closer to the real teeth, and meanwhile, the cast porcelain teeth do not contain metal, so that the stimulation of the metal inner crown of the porcelain teeth to the gum can be avoided.

The cast porcelain tooth needs to be formed in a high-temperature environment, and not only a certain pressure needs to be applied in the casting process, but also a certain degree of vacuum needs to be maintained. The prior art adopts a plunger rod arranged at the top of a hearth, and the plunger rod penetrates through a top plate of the hearth from the top of the hearth and directly extends into a high-temperature heating zone in the hearth. During die casting, the punch rod goes deep into a die casting hole in the center of a workpiece to be cast placed in the hearth to die-cast a hot-die-casting material in the hole, the diameter sizes of the die casting hole and the punch rod are consistent, and the punch rod and the die casting hole are concentrically aligned. The defects of the prior art mainly comprise the following three aspects:

firstly, the sealing material of the punch rod in the prior art is easy to lose efficacy at high temperature and has short service life; in the prior art, a ceramic punch penetrates through the top of a hearth and aims at a workpiece to be die-cast in the hearth at high temperature for die-casting, the punch directly penetrates into the high-temperature hearth for die-casting the workpiece, the punch is heated in a high-temperature zone of the hearth, the temperature of the punch is extremely high, and the high-temperature failure of a punch sealing material closely contacted with the punch is caused, so that the whole hearth cannot reach a vacuum environment required by ceramic tooth casting, and the casting failure is caused. In the prior art, a fan, a radiating fin and other devices are additionally arranged outside the top for radiating, but the actual radiating effect is not ideal because the punch sealing material is in direct contact with the high-temperature punch.

Secondly, treat die-casting work piece locating position high-demand as above-mentioned prior art, difficult operation. Firstly, a workpiece to be die-cast is placed on a hearth base, then the hearth and the hearth base are driven to be closed by a power device, and finally, a punch rod penetrating through the top of the hearth carries out die-casting on a central die-casting hole of the workpiece to be die-cast on the base. The operation engineering must ensure that the die casting hole at the center of the workpiece to be cast on the base is concentric with the punch rod penetrating through the top, and if the die casting hole center of the workpiece to be cast and the punch rod have concentric deviation, the punch rod cannot accurately enter the die casting hole, so that the die casting failure is caused.

Thirdly, only one punch rod is used for die-casting the die-casting hole in the center of the workpiece in the prior art, when a large workpiece is die-cast, the casting channel is too long, the flowability of the die-casting material is poor, and the casting failure is easily caused.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a multi-punch die-casting device of a porcelain casting furnace for dentistry.

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

a multi-ram die-casting device of a porcelain casting furnace for dentistry is provided with a hearth, wherein the hearth is of a structure with openings at the top and the bottom; the bottom opening of the hearth is sealed by a hearth bottom plate; a furnace core is arranged in the hearth; the furnace core is of a structure with openings at the top and the bottom; the top of the furnace core is contacted with the top plate of the inner lining of the hearth; a workpiece sand mold to be cast is arranged in the furnace core; the sand mould of the workpiece to be cast is arranged at the top of the furnace door; a mold cavity is arranged in the sand mold of the workpiece to be cast; the top of the cavity is provided with a plurality of die-casting holes communicated with the cavity, and a hot-press casting ceramic block is placed in each die-casting hole; a punch is arranged at the top of each hot-press cast ceramic block; the top of the punch rod protrudes out of the top surface of the sand mold and is lower than the top surface of the furnace core, namely a space for the punch rod to ascend is formed between the top of the punch rod and the bottom surface of the lining top plate in the hearth; the furnace door is of a structure capable of lifting relative to the hearth, the furnace door acts relative to the hearth, and when the plunger rod is in contact with the bottom surface of the lining top plate, die casting is carried out by utilizing acting force between the lining top plate and the plunger rod.

A driving mechanism which is used for driving the furnace door and a workpiece sand mold to be cast to lift in the furnace core is arranged corresponding to the furnace door; the driving mechanism is provided with an inner tray for supporting the oven door; the furnace door is made of heat insulating materials and separates a high-temperature area of the hearth from the inner tray;

the inner tray is connected with the power part through a push rod arranged at the bottom of the outer side of the hearth, the push rod pushes the inner tray, the furnace door, the sand mold and the punch to move upwards under the action of the power part, and when the punch moves upwards and contacts with the bottom surface of the lining top plate, the lining top plate is used for preventing the reaction force of the punch moving upwards to perform die casting.

A motor for driving the hearth to lift is arranged corresponding to the hearth; the hearth descends to enable the hearth bottom plate to be hermetically connected with the outer tray when the hearth descends.

The hearth comprises a shell and a lining; the shell is provided with a hearth shell which is of a frame structure and has openings at the upper end and the lower end; the top and the bottom of the hearth shell are respectively sealed by a hearth top plate and a hearth bottom plate; the hearth bottom plate is provided with a through hole for a furnace door to pass through; the hearth is a structure which can be lifted under the action of a hearth lifting motor; the hearth bottom plate and the outer tray are hermetically connected with the outer tray when the hearth descends; the lining is provided with hearth linings positioned on the left side and the right side of the furnace core and lining top plates; the hearth linings on the left side and the right side and the lining top plate form a hearth lining with an opening at the lower end.

The shell of the hearth is provided with an air exhaust hole, and the air exhaust hole provides a high-temperature and vacuum environment for casting the cast porcelain teeth through a vacuumizing device.

And a ceramic plate is arranged between the lining top plate and the furnace core.

And a heating body is arranged in the furnace core.

The power part is provided with a power element used for providing ascending or descending for the push rod; a screw rod of the power element is provided with a guide rod nut flange; the guide rod nut flange is fixedly connected with the transmission flange, a pressure sensor is installed between the transmission flange and the push rod, the power element transmits force to the push rod through the transmission flange, the push rod pushes the inner tray to lift, and the speed and the value of the force applied by the power device are adjusted through the pressure value obtained by the pressure sensor, so that the die-casting effect of the workpiece is guaranteed.

A guide mechanism is arranged corresponding to the push rod; the guide mechanism comprises a guide rod upper support and a guide rod lower support; the guide rod upper support is fixedly arranged on the tray base; a plurality of guide rods are arranged between the guide rod upper support and the guide rod lower support, guide sleeves are sleeved on the guide rods and connected with the transmission flange through guide rod connecting pieces, so that the motion direction of the push rod is ensured to be parallel to the guide rods; the tray base is fixedly connected with the base through the left support and the right support.

The power element is a motor or an air cylinder or an electric push rod which can rotate forward and backward.

The invention provides a multi-plunger die-casting device for a porcelain casting furnace, which has the following beneficial effects by adopting the technical scheme;

firstly, in order to solve the problems that the service life of a plunger sealing material is short and the vacuum can not be maintained due to high-temperature failure in the prior art, the invention designs an upward pushing device from the lower part of a furnace door at the bottom of a furnace chamber to push the furnace door bearing a workpiece to be pressed to move towards the inside of the furnace chamber. When the tops of a plurality of stamping rods placed in die-casting holes in the upper part of a workpiece to be pressed are contacted with the lower end surface of the top of a hearth, die-casting is carried out by utilizing the reaction force of the top of the hearth for preventing the workpiece from moving upwards; the push rod for pushing the furnace door to move upwards is always far away from the high-temperature heating area of the hearth, so that the temperature of the push rod is not high, and the sealing material can be effectively used for a long time, so that the vacuum in the hearth is ensured.

Secondly, the problem of the requirement on the placing position precision of the workpiece to be pressed in the prior art is solved. The invention adopts the mode that a plurality of punching rods are placed in the central die-casting hole of the workpiece to be pressed before the workpiece to be pressed enters the furnace, thus the operation is easy. In addition, the lower end face of the top of the hearth is provided with a ceramic flat plate, when a short punch in a workpiece die-casting center hole contacts a ceramic plate at the top of the hearth, any contact point of the whole flat ceramic plate can push and press the punch under the reaction force; therefore, the workpiece to be pressed has no requirement on the accuracy of the placement position.

Finally, aiming at a larger die-casting workpiece, the invention adopts a scheme of die-casting with a plurality of punching rods simultaneously, namely, a plurality of die-casting holes can be arranged on the top of the workpiece to be pressed according to the requirement, and the punching rod is arranged in each die-casting hole, so that a die-casting channel is added, the die-casting is easier to succeed than the existing single-channel die-casting, and the defect that only one punching rod can be used for die-casting in the prior art is overcome.

In conclusion, the invention solves the problems that in the prior art, the punch rod penetrating through the top of the hearth enters the high-temperature zone of the hearth, so that the sealing material of the punch rod fails at high temperature, the hearth is leaked in vacuum, and the precision requirement on the position of a workpiece is high, so that the operation is difficult; the casting of a large workpiece is easy to fail due to the die casting of a single punch rod; especially, the design of the multi-punch method provides a brand new design method which cannot be solved by the prior art scheme (only one punch can be used for die casting), and has the characteristics of simple and convenient operation and high die casting precision.

Drawings

Fig. 1 is a perspective view of the present invention.

FIG. 2 is a schematic cross-sectional view of the present invention.

In the figure: 1. a left bracket; 2. a base; 3. a motor bracket; 4. a power element; 5. a guide rod lower support; 6. a right bracket; 7. a guide rod nut flange; 8. a transmission flange; 9. a guide bar; 10. a guide sleeve; 11. a guide rod coupling member; 12. a pressure sensor; 13. a push rod; 14. a tray base; 15. an outer tray support; 16. an outer tray; 17. a hearth floor; 18. a housing; 19. a hearth roof; 20. a lining top plate; 21. a ceramic plate; 22. punching; 25. 26, carrying out hot-press casting on the ceramic blocks; 27. a cavity; 28. a heating body; 29. a furnace core; 30. a furnace door; 31. lining of the hearth; 32. an inner tray; 33. a flange seal ring; 34. a push rod sealing ring 1; 35. an outer tray seal ring; 36. a push rod sealing ring 2; 37. sealing the flange; 38. a guide rod upper support; 39. and (4) air exhaust holes.

Detailed Description

The technical solutions in the embodiments of the present invention will be described in detail and fully with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

Referring to fig. 1, a schematic perspective view of an embodiment of the present invention and a cross-sectional view of the embodiment of fig. 2. For the convenience of understanding, a machine shell part outside the porcelain casting furnace and a furnace chamber lifting device part of the porcelain casting furnace are hidden in the drawing. As shown in the figure, the multi-plunger ceramic casting furnace die casting device comprises a ceramic plate 21, a heating device 28, a furnace door 30 for bearing a casting to be cast, an inner tray 32, an outer tray 16, a push rod 13, a plurality of plungers 22 and the like, a sealing flange 37 and the like, a pressure sensor 12, a transmission flange 8 and an inner tray driving motor 4.

The hearth shell comprises a hearth top plate 19, a hearth shell 18, a hearth bottom plate 17, an outer tray 16 and the like, and a hearth lining 31 made of heat-insulating materials, a lining top plate 20, a furnace core 29, a furnace door 30, a heating body 28, a ceramic plate 21 and the like are connected and assembled to form the heating hearth. Under the action of a not shown drive hearth lifting motor, the hearth descends, so that the hearth bottom plate 17 and the outer tray 16 are hermetically connected by virtue of an outer tray sealing ring 37. The sealing flange 37 forms a closed hearth cavity together with the hearth elements and the like through the flange sealing ring 33 and the push rod sealing rings 34 and 36. A high-temperature, vacuum environment can be provided for the casting of the cast porcelain tooth through the extraction holes 39 in combination with a not-shown evacuation device.

The push rod 13 pushes the inner tray 32 fixedly connected with the push rod to support the oven door 30 and the sand mold (casting ring) 26 carried by the oven door to move towards the upper part of the hearth, when the tops of a plurality of punch rods 22, 23, 24 (one or more punch rods) and the like placed in the die-casting holes of the sand mold (casting ring) 26 contact the lower end plane of the ceramic plate 21, under the reaction force applied to the ceramic plate 21, the punch rods push and press the hot-cast porcelain blocks 25 to enter the cavities 27 of the sand mold (casting ring) 26 and fill the hot-cast porcelain blocks, and die-casting is realized. The material to be processed in the invention comprises hot-pressed cast porcelain block material filled in a sand mould.

Specifically, referring to fig. 1 and fig. 2, a perspective view and a cross-sectional view of the present invention are shown, respectively. As shown, the push rod 13 extends through the outer tray 16 and is fixedly connected to the inner tray 32. The push rod 13 and the outer tray 16 are hermetically connected through a sealing flange 37, wherein the sealing flange 37 is fixedly connected on the outer tray 16, and the contact surface of the push rod and the outer tray is sealed through a flange sealing ring 33; preferably, the pushrod 13 is sealed to the sealing flange 37 by a plurality of pushrod seals 34, 36, etc. mounted within the sealing flange 37. Of course, the sealing ring can also be arranged on the push rod 13, and the inner tray 32 and the push rod can also be a complete workpiece.

Preferably, a heat insulating material door 30 is placed over the inner tray 32 to insulate the high temperature zone of the furnace from the inner tray. The influence of heat conduction modes such as heat radiation on the push rod 13, the flange sealing ring 33 and the push rod sealing rings 34 and 35 is reduced, so that the sealing material can be effectively used for a long time, and the vacuum of the hearth can not be leaked due to high-temperature failure of the sealing material.

The preferred ceramic plate 21 is placed on the top of the inner part of a hearth lining 31 made of a hearth heat insulation material, when the push rod 13 pushes the inner tray 32 and the upper furnace door 30 to move towards the upper part of the inner part of the hearth, a sand mold (casting ring) 26 on the furnace door 30 moves towards the top of the inner part of the hearth along with the furnace door 30, and a plurality of punching rods 22, 23, 24 and the like placed in die casting holes of the sand mold (casting ring) 26 contact the lower end face of the ceramic plate 21 along with the rising of the furnace door 30, and the ceramic plate 21 prevents the punching rods 22, 23, 24 from moving upwards so as to apply force to the punching rods 22, 23, 24. The ceramic plate 21 having high hardness and strength is preferably used as a member for applying a reaction force by being in contact with the punches 22, 23, 24, etc., but the entire inner liner top plate 20 or other materials may be used as the member for applying a reaction force.

Preferably, in the present embodiment, the power device for raising or lowering the push rod 13 is a motor 4 capable of rotating in forward and reverse directions, but a cylinder or an electric push rod may be used.

Preferably, a guide rod nut flange 7 is installed on a screw rod of an inner tray driving motor 4 which provides a power device for a push rod 13, the guide rod nut flange 7 is fixedly connected with a transmission flange 8, a pressure sensor 12 is installed between the transmission flange 8 and the push rod 13, the power device transmits force to the push rod through the transmission flange 8, and the push rod pushes the inner tray to lift. The pressure value obtained by the pressure sensor 12 is used for adjusting the speed and the value of the force applied by the power device so as to ensure the die-casting effect of the workpiece

Preferably, in the embodiment, the outer tray 16 is connected to the outer tray support 15 through a buffer element, and the inner tray 32 can be pushed by the push rod 13 to be lifted. Of course, the method can also be modified to make the inner tray 32 fixed and the outer tray 16 descend together with the hearth, so that the furnace door rises relative to the hearth, and die casting is realized.

Preferably, before the push rod 13 pushes the furnace door 30 to ascend or during die casting, a vacuum pumping device, not shown, can provide a vacuum environment for the furnace chamber through the pumping hole 39, and under the action of the atmospheric pressure, the whole furnace chamber is hermetically combined through the furnace chamber bottom plate 17 and the outer tray 16 by virtue of the sealing material on the outer tray 16 to form a complete vacuum furnace chamber. And when in die casting, the hearth bottom plate 17 and the outer tray 16 are kept to form a closed cavity by using atmospheric pressure and are not separated by the acting force of die casting.

Preferably, the lower guide rod support 5 is fixedly installed on the motor bracket 3, the upper guide rod support 38 is fixedly installed on the tray base 14, a plurality of guide rods 9 are installed between the lower guide rod support and the tray base, guide sleeves 10 are sleeved on the guide rods, and the guide sleeves 10 are connected with the transmission flange 8 through guide rod connecting pieces 11 to ensure that the moving direction of the push rod 13 is parallel to the guide rods. The left bracket 1 and the right bracket 6 are used for fixedly connecting the tray base 14 and the base 2 together.

It should be noted that, in the embodiment of the present invention, directional indications (such as up, down, left, right, front, and back … …) are involved, and the directional indications are only used for explaining the relative positional relationship, motion conditions, and the like between the components in a certain posture (as shown in the drawing), and if the certain posture is changed, the directional indications are changed accordingly.

In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The embodiments described above are only a part of the embodiments of the present invention, but the present invention is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are included in the scope defined by the claims of the present application.