Fluid sprinkling – spraying – and diffusing – Rigid fluid confining distributor – Including flow passage liner
Reexamination Certificate
2000-05-17
2001-10-09
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Rigid fluid confining distributor
Including flow passage liner
C239S596000, C239S200000
Reexamination Certificate
active
06299078
ABSTRACT:
BACKGROUND OF THE INVENTION
Contemporary fluid dispense systems are well suited for dispensing precise amounts of fluid at precise positions on a substrate. A pump transports the fluid to a dispense tip, also referred to as a “pin” or “needle”, which is positioned over the substrate by a micropositioner, thereby providing patterns of fluid on the substrate as needed. As an example application, fluid delivery systems can be utilized for depositing precise volumes of adhesives, for example, glue, resin, or paste, during a circuit board assembly process, in the form of dots for high-speed applications, or in the form of lines for providing underfill or encapsulation.
Contemporary dispensing pumps comprise a syringe, a feed tube, a dispense cartridge, and pump drive mechanism. The syringe contains fluid for dispensing, and has an opening at its distal end at which a feed tube is connected. The feed tube is a flexible, hollow tube for delivering the fluid to the cartridge. The cartridge is hollow and cylindrical and includes an inlet neck at which the opposite end of the feed tube is connected. The inlet neck directs the fluid into the hollow, central cartridge chamber.
A feed screw disposed longitudinally through the center of the cylindrical chamber transports the fluid in Archimedes principle fashion from the inlet to a dispensing needle attached to the chamber outlet. A continuously-running motor drives the feed screw via a rotary clutch, which is selectively actuated to engage the feed screw and thereby effect dispensing. A bellows linkage between the motor and cartridge allows for flexibility in system alignment.
Pump systems can be characterized generally as “fixed-z” or “floating-z” (floating-z is also referred to as “compliant-z”. Fixed-z systems are adapted for applications that do not require contact between the dispense tip and the substrate during dispensing. In fixed-z applications, the dispense tip is positioned and suspended above the substrate by a predetermined amount, and the fluid is dropped onto the substrate from above. In floating-z applications, the tip is provided with a standoff, or “foot”, designed to contact the substrate as fluid is delivered by the pump through the tip. Such floating-z systems allow for tip travel, relative to the pump body, such that the entire weight of the pump does not bear down on the substrate.
Pump manufacturers commonly include their own custom interface for mounting dispense needles to the pumps. Customers investing a great deal of resources in a particular pump system are therefore limited to purchasing compliant dispense needles directly from the pump manufacturers. This arrangement is not optimal for the customer, since after-market dispensing needles are often times superior in performance and reliability. For example, the dispense needles disclosed in U.S. patent application Ser. No. 09/491,615, filed Jan. 26, 2000, incorporated herein by reference, offer the capability of precise dispensing at higher throughput rates, higher reliability, and reduced dispensing widths. Such high-performance dispense needles are incompatible with the current aforementioned manufacturer-specific systems.
SUMMARY OF THE INVENTION
The present invention is directed to an adapter that affords compatibility between high-performance dispensing needles and conventional pump systems.
In a first aspect, the present invention is directed to an adapter for securing a dispensing needle to a dispensing pump. The dispensing pump includes an outlet through which dispensed material is delivered, and includes an output body with alignment pins extending therefrom and first threads about the body. The dispensing needle includes a longitudinally-disposed body and neck, the body and neck including a longitudinal port providing a path for delivery of the dispensed material through the dispensing needle. The body of the dispensing needle includes an outer surface that is keyed for angular positioning of the needle with respect to the pump. The adapter includes an alignment plate, and index plate and an adapter nut. The alignment plate comprises a plurality of alignment holes for mating with the alignment pins, a material aperture aligned with the pump outlet, and a plurality of index pins extending from the body of the alignment plate. The index plate comprises a plurality of index holes for mating with the index pins, the index holes spaced to provide for positioning of the index plate with respect to the alignment plate at a plurality of discrete angular positions. The index plate further includes an orientation pocket having a keyed inner surface substantially matched to the outer surface of the body of the dispensing needle. The nut has an inner recess for containing the index plate and the alignment plate, and further includes a pin aperture in alignment with the orientation pocket and second threads for mating with the first threads. When the nut is tightened, index plate and alignment plate are secured against the pump output body.
The material aperture of the alignment plate preferably comprises a tapered funnel. The alignment holes are preferably positioned on opposite sides of the aperture. The alignment plate and index plate are preferably substantially disk-shaped. The index holes are preferably spatially positioned in a circular array about the orientation pocket, for example at 45 degree increments about the orientation pocket.
The inner surface of the orientation pocket may be substantially cylindrical and the keyed inner surface thereof may comprises a flat surface formed in the cylindrical inner surface such that the dispense needle has a single orientation with respect to the index plate.
An adapter kit may be provided comprising the adapter, a compartmentalized receptacle, dispense tip inspection accessories, dispense tip cleaning accessories, and dispense tip handling accessories.
REFERENCES:
patent: 5236227 (1993-08-01), Adams et al.
patent: 5366312 (1994-11-01), Raines
patent: 5401062 (1995-03-01), Vowles
patent: 5636796 (1997-06-01), Oguma
patent: 5685485 (1997-11-01), Mock et al.
Bradford Labs LLC
Hwu Davis
Mills & Onello LLP
Scherbel David A.
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