EP1635062B1

EP1635062B1 - Airless spray pump

Info

Publication number: EP1635062B1
Application number: EP05077480A
Authority: EP
Inventors: Glen W Davidson; Alexander P Kapelevich
Original assignee: Graco Minnesota Inc
Current assignee: Graco Minnesota Inc
Priority date: 1999-08-31
Filing date: 2000-08-28
Publication date: 2012-06-13
Anticipated expiration: 2020-08-28
Also published as: EP1635062A1

Description

TECHNICAL FIELD

Airless spray pumps for the spraying of paints and other coatings.

BACKGROUND ART

Airless spray pumps for the spraying of paints and other coatings via the airless method are well known and have traditionally been divided into two types, diaphragm pumps for the lower end of the market and reciprocating piston pumps for the higher end.
United States patent no. 5,567,323 , issued on 22nd October 1996, describes a paint spraying apparatus show a filter having a top member, which is attached to a bottom member composed of a base and an accordion-shaped fine wire mesh filter element. The mesh filter element has an outer peripheral surface and an inner peripheral surface. The top of the filter has attached thereto a male threaded portion for attachment to a corresponding female-threaded portion of a rod. The rod is con>nected to the rest of an airless paint sprayer. A hose having at a distal end thereof a spray gun is connected at its proximal end to an outlet of the sprayer. The top of the filter disconnects and reconnects, to permit cleaning of the filter for re-use. Such disconnection of the top permit the thorough cleaning of all components of the filter.
In US 5,842,639 , issued on 1st December 1998, a paint sprayer filter is described, which is easily removable for cleaning purposes. The filter is in two parts: firstly, a disk having an internal bead and a downwardly depending coupling portion having a female thread, and secondly, a cone portion having a number of holes through which paint is filtered. The cone has a lip at its broader end. The lip engages with the bead to form an assembled unit. In use the thread is secured to a male thread provided at the end of a hose, which conveys the paint to a spray gun.
A yoke support for a reciprocating member in a portable paint spraying equipment is the subject of US 5,769,321 , issued on 23rd June 1998. The support has a slot in the housing perpendicular to an axis of reciprocation, and an extension on the reciprocating member and a removable support secured to the housing and aligned with the extension of the reciprocating member and carrying a bearing sized to receive the extension in sliding relationship, such that the bearing supports the extension of the reciprocating member in alignment with the housing, and the removable support allows installation and removal of the reciprocating member by providing clearance for the extension via the slot in the housing when the removable support is removed.
In US 4,416,588 , issued on 22nd November 1983, a combination airless paint pump and air compressor are described, in which a prime mover drives an eccentric cam wheel within an oil reservoir housing. A piston, which is movably received within a housing bore, is engageable with a periphery of the cam wheel to load an hydraulic column open to the piston cylinder for oscillating a paint spray pump diaphragm. A second piston member, which is received in a bore open to the housing, is engageable with the periphery of the cam wheel spaced circumferentially of the paint pump piston. The second piston is operatively connected with an air pump diaphragm. Selector means are provided to selectively disengage either one of the pistons from contact with the cam wheel, whereby the unit can operate in a paint-only mode, an air-only mode or a combination air and paint mode.

DISCLOSURE OF THE INVENTION

According to the present invention, there is provided a method as defined in claim 1.
The objects and advantages of the invention will appear more fully from the following description made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a prospective exploded view showing an airless spray pump.
FIG. 2 is a simple front plan view of the drive assembly and pump.
FIG. 3 is a side plan view of the assembly shown in FIG. 1.
FIG. 4 is a detailed exploded view of the circled area in FIG. 3.
FIG. 5 is a cross-sectional view of the pump.
FIG. 6 shows more details of the drive assembly.
FIG. 7 is another cross-sectional view of the pump portion.
FIG. 8 is a cross-section of the outlet filter.
FIG. 9 is an exploded view of the outlet filter
FIG. 10 is a perspective exploded view of the airless spray pump.

BEST MODE FOR CARRYING OUT THE INVENTION

An airless spray pump generally designated 10 is comprised of a main drive housing 12 having a motor 14 mounted to the rear thereof. A gear assembly 16 having a rear bearing 17 and gear teeth 22 is inserted into the bearing housing 20 of drive housing 12. Gear teeth 22 on gear assembly 16 mate with the teeth on pinion 24 on the end of motor 14. The teeth 22 and on pinion 24 are formed with a 5° helical angle and have a 25° pressure angle. This geometry, which is not part of the claimed subject matter, combines the higher efficiency of straight cut gears with the noise reduction typified in a helical design.
An eccentric 25 is also molded onto the front of gear assembly 16 and has located thereabout a bearing assembly 28 which rides inside a yoke 30. Yoke 30 moves vertically on guide rods 32 which are retained in pockets 34 of drive housing 12. Yoke 30 is molded of plastic. Gear assembly 16 is cast in ZA-12 with an integral counterweight leading to lower cost and easier manufacture.
Pump rod 36 is provided with a cap 38 over the top end thereof which has bearing upon it bearing 28. Pump assembly 40 is designed as a single acting pump that is the pump only pumps on the downward stroke and loads on the upward stroke. In doing so this allows the components of the drive train, including the yoke and gear, to be much lighter as the yoke 30 ends up being more of a guidance device rather than a force-applying device.
As can be seen more particularly in FIG. 2, motor and pinion 24 are offset from the centerline 42 of pump assembly 40 which also has offset therefrom bearing 20 in the opposite direction. Also, this arrangement does not have any significant cantilevering as the pump rod, pinion, yoke, eccentric and cap are all located in the same plane. The location of the rod and the single acting pump with respect to the gear centerline reduces the thrust loads on the yoke. The location of the pinion on the gear partially offsets and reduces the pump forces on the gear shaft and bearings. By locating the eccentric bearing directly on the end of the pump rod cap which is press-fit it eliminates the transfer of pumping force through an intermediate member such as the yoke which provides longer life, efficiency and allows the manufacture of a more inexpensive yoke assembly.
The shaft packing assembly 44 shown in FIG. 4 is comprised of a packing housing 46 which screws into pump housing 48 and which contains a felt member 50 which has been soaked with throat seal lubricant or other solvent or lubricant. A stack of v-packings 52 are compressed in place by wave spring 54 which is tightened by tightening seal housing 46 into pump housing 48.
Turning to FIG. 7, inlet check 56 is provided with a check ball 58, a check seat 60 which is pressed into check housing 62 and which is held in place by retainer and integral ball guide 64. These parts all press-fit into one another such that the complete assembly be merely screwed into main pump housing 48 for replacement. Similarly, outlet check assembly is formed of an outlet check housing 60 which is screwed into pump housing 48 and similarly is provided with a check ball 62 held in place by ball seat 65. As can also be seen in FIG. 7, the outlet passageway 66 is angled relative to the axis of pump shaft 36. This allows the outlet check assembly 58 to operate essentially via gravity and yet requires only the drilling and provision of one passageway while maintaining an essentially vertical ball-seat relationship.
FIGs. 8 and 9 show the outlet filter assembly 80 which is comprised of a filter element 82 contained in passage 84 of pump assembly 40 and which is retained by fitting 86.
Turning to FIG. 10, inlet tube 70 is provided with a female threaded end 70a. Inlet filter screen assembly 72 has a male threaded end 72a for threaded engagement with end 70a. Ends 70a and 72a use the same size and thread as a common garden hose such that a user need merely remove screen assembly 72, attach a garden hose to inlet tube 70, turn on the water and flush out the assembly.
It is contemplated that various changes and modifications may be made to the airless spray pump without departing from the scope of the invention as defined by the following claims.

Claims

A method of flushing for an airless spray pump assembly, the airless spray pump assembly comprising a pump portion (40), an inlet tube (70), and an inlet filter screen assembly (72), wherein said inlet tube (70) is provided with a female threaded end (70a) and said inlet filter screen assembly (72) is provided with a male threaded end (72a) in threaded engagement with said female threaded end, said inlet filter screen assembly (72) being thereby removable from said inlet tube (70),
the method comprising:
removing said inlet filter screen assembly (72) from said inlet tube (70);

attaching a garden hose to said inlet tube (70); and

flushing out said inlet tube (70) and pump portion (40) using said garden hose.