Patent Application
20080237257
The present invention relates generally to the field of metering and dispensing equipment and, more particularly, to an improved positive displacement material metering system employing fewer components while increasing the precision at which the material is metered.
Metering and dispensing systems are generally employed to provide a measured flow of material from a material reservoir to a particular application. For example, many operations in the manufacture of an automobile require precisely metered materials such as the application of sealants to the automobile's body structure and in the molding of the material used in seating applications. Metering and dispensing devices ensure that a specified amount of material is delivered to the application each time the material is required. Metering and dispensing devices eliminate the guess work, human error, and waste associated with having to apply a precise amount of material to an application at each required cycle.
Metering and dispensing devices are known in the art for metering and dispensing specified quantities of materials, such as sealants, adhesives, epoxies, and the like. Metering and dispensing devices are designed around the concept of a piston and cylinder. The piston is connected to a connecting rod that slides the piston fore and aft throughout the length of the cylinder much in the same way the piston works in an internal combustion engine. The connecting rod is then connected to a driveshaft that is operated by a motor. In metering and dispensing devices, when the piston reaches a specified location in the cylinder, material is allowed to fill through a cylinder inlet. When the cylinder has been filled, the piston is pushed by the connecting rod through the length of the cylinder, which in turn, forces the material out a cylinder outlet. The amount of material in the cylinder and dispersed during each cycle is a product of the cylinder height and the piston/cylinder diameter. The material can be metered either by changing the cylinder height or piston/cylinder diameter.
While the prior art does offer an adequate means for metering and dispensing materials, they are however, not optimal. First, a number of prior art metering and dispensing systems require a number of components to operate. Specifically, the piston/connecting rod/driveshaft relationship involve a number of individual components for operation (valves, cylinder, piston, connecting rod, driveshaft, and various fasteners to connect the components). Second, it is also known in the art to combine two or more metering systems together to control the flow of two or more component materials so that they may be mixed together for a particular application. However, if multiple metering and dispensing systems are required for a particular operation, a number of valves, pistons, connecting rods, and driveshafts may be required. Because a number of components are required to operate the system, this may have a significant impact on the cost to the end user. Third, with pumps employing the piston variation having depressions to control the flow of material in the cylinder, some material metering precision may be lost because there may always be some unknown amount material left in the cylinder by the depression in the piston. Finally, in order to operate a number of systems together to ensure the precise amount of material is dispensed at the correct point in time for the application, the pistons will have to be connected to by the same driveshaft. This arrangement may make for a very large piece of equipment that may consume large amounts of valuable plant floor space.
Therefore, a need exists for a positive displacement material metering system that can be utilized in compact areas and operates with fewer components while at the same time maintaining a precise delivery of material to an application on each and every required cycle. A need also exists for a material metering system that is easily expandable by simply adding cylinders or chambers and pistons as required by a particular application. The present invention satisfies these requirements.
The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims, and drawings, of which the following is a brief description:
The present embodiments provide a positive displacement metering device for use in applying a measured amount of resin, epoxy, glue, grease, or the like in a manufacturing environment. Referring to
Referring now to
Main portion 18 of housing 14 further includes at least one material inlet port 30 and at least one material outlet port 32. Both inlet port 30 and outlet port 32 pass from an outer surface 34 of housing 14 to interior surface 22. Both inlet port 30 and outlet port 32 are cylinders having an axis B that is generally perpendicular to axis A. Both inlet port 30 and outlet port 23 may include couplings (not shown) at outer surface 34 that allow hoses or some other means to be attached to housing 14 so that material can be supplied to metering device 10 through inlet port 30 and dispensed from metering device 10 through outlet port 32.
Spindle 16 includes a metering chamber 36 that passes completely though spindle 16 and is centered about axis B when aligned with inlet port 30 and outlet port 32. Chamber 36 is cylindrical in shape and captures a metering piston 38 that is allowed to freely rotate about axis B and freely slide throughout chamber 36 as spindle 16 is rotated about axis A. The diameter at a first end 40 of chamber 36 is smaller than the diameter of a main portion 41 of chamber 36. The smaller diameter first end 40 prevents piston 38 from passing out of chamber 36 during operation of metering device 10. The diameter of a second end 42 of chamber 36 remains the same diameter as main portion 41 of chamber 36 so that piston 38 can be easily loaded into chamber 36. Piston 38 is captured within chamber 36 at second end 42 by a locking mechanism 44 that locks and seals against the walls of chamber 36. Both first end 40 and locking mechanism 44 include holes 46 so that material can pass in and out of chamber 36. Valves are not necessary to meter the flow of material to inlet port 30 or out of outlet port 32.
In an embodiment of the present invention shown in
Metering device 10 is assembled by inserting metering piston 38 into metering chamber 36 of spindle 16. Next, spindle 16 is inserted into main portion 18 so that material inlet port 30 and material outlet port 32 of housing 14 are aligned with chamber 36 in spindle 16. Seals 28 are added to housing 14 and, finally, capturing portion 20 and bearings 26 are secured to main portion 18 to capture spindle 16. An end 48 of spindle 16 can be connected to any conventional motor 12 so that spindle 16 can be rotated within housing 14 when metered material is required.
Spindle 16′ includes a metering chamber 36′ having three segments. A first segment 50 and a third segment 52 are cylindrical in shape, centered about axis B and axis C respectively, and are generally perpendicular to axis A. A second segment 54 is also cylindrical in shape, however, second segment 54 is centered about axis A and generally perpendicular to both first and third segments 50 and 52. First segment 50 includes a first hole 56 that corresponds to a first opening 58 in second segment 54. Third segment 52 includes a second hole 60 that corresponds to a second opening 62 in second segment 54. Segments 50, 52, and 54 cooperatively form chamber 36′ and are connected such that material may flow from a first end 64 of first segment 50 through second segment 54 to a first end 66 of third segment 52 and in the reverse as well.
A metering piston 38′ is included in spindle 16′ and captured in second segment 54 of metering chamber 36′. Piston 38′ is allowed to freely slide and rotate about axis A within chamber 36′. Piston 38′, however, is prevented from fully entering first and third segments 50 and 52 by stops 68 that have been machined into chamber 36′. It is undesirable to allow piston 38′ to fully enter into first and third segments 50 and 52 because a surface 70 of piston 38′ should be presented to the material entering chamber 36′ so that material can access a sufficient portion of piston 38′ surface area to force piston 38′ to move within chamber 36′. In this particular embodiment, spindle 16′ may be a two-piece assembly so that second segment 54 of chamber 36′ can be properly machined both in a first half 72 and in a second half 74 of chamber 36′. Piston 38′ can be loaded into one half of second segment 54 prior to securing two halves 72, 74 of spindle 16′ together and creating second segment 54 of chamber 36′.
In this particular embodiment, metering device 10′ is assembled in the following manner. Piston 38′ is seated in second segment 54 of chamber 36′ in first half 72 of spindle 16′. Second half 74 of spindle 16′ is connected to first half 72 to create the entire second segment 54 and a complete spindle assembly 16′. Next spindle 16′ is inserted into main portion 18′ of housing 14′ so that material inlet ports 30′ and material outlet ports 32′ are aligned with corresponding holes 56, 60 of chamber 36′. Capturing portions 20′ are assembled to main portion 18′ to capture spindle 16′ within housing 14′. An end 48′ of spindle 16′ can be connected to any conventional motor 12 so that spindle 16′ can be rotated within housing 14′ when metered material is required.
All the embodiments described above operate in the same fashion. The difference between the embodiments relate to the number and types of materials to be metered, whether those materials can be mixed or should remain separate, and at what cycle time are the materials required to be delivered to a particular application. As will be appreciated, the following is a description of the general operation of metering device 10, keeping in mind that the same principles of operation apply to multiple metering devices 10 as well.
Now referring to
Now referring to
As discussed above, spindles 16, 16′ may include multiple chambers 36, 36′ for dispensing metered material and can be located at different angles relative to each other within spindle 16, 16′. The number of chambers 36, 36′ required and the angle of location relative to each other is completely dependant on the operation or application in use. Also, the amount of metered material can be varied simply by modifying the height of piston 38, 38′ and/or modifying the bore diameter of chamber 36, 36′.
Metering device 10, 10′ may be manufactured from any number and combination of materials such as metals, polymers, or ceramics. For example, housing 14, 14′, spindle 16, 16′ and piston 38, 38′ may be manufactured out of a ceramic material if the required metering of material is highly precise because ceramic components may be manufactured with tighter tolerances versus other materials. However, if durability of metering device 10, 10′ is a concern, then less brittle metallic materials such as aluminum or steel may be better suited for the particular application.
The present invention has been particularly shown and described with reference to the foregoing embodiments, which are merely illustrative of the best modes for carrying out the invention. It should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11047439 | Jan 2005 | US |
| Child | 12137451 | US |
