Air Driven Abrading Device

Abstract

An air powered device for abrading wall and floor surfaces. A turbine is disclosed within a dome-like housing. An abrading disc is powered by the turbine via a gear reduction drive. A source of reduced air pressure draws air into the housing past the periphery of the disc for the pick up of dust particles with the airflow path being inwardly to an area of low pressure located centrally of the turbine. A conduit member in communication with said source is movably attached to the dome-like housing and may additionally serve as a hand hold. An air barrier restricts the incoming airflow to the path over the periphery of the abrading disc.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to abrading devices and more particularly to such a device jointly utilizing an intake flow of air to power same and to remove abraded particles.

The prior art devices for the abrading or surfacing of flat surfaces are for the most part limited to machines restricted by their size to use on horizontal surfaces. Such machines typically include a power source in close proximity to the disc or belt abrading element. In the typical use of such machines their weight rests entirely on the surface being abraded hence the weight of same is not critical. While it would be advantageous to use powered abrading equipment on upright wall surfaces the weight and size of existing machines makes them impractical for such tasks.

To the extent the prior art is known, powered abrading tools are either of the type restricted to use on floor surfaces or are of the hand held, compact design for use in the sanding of only very small flat areas as on furniture.

SUMMARY OF THE PRESENT INVENTION

The instant invention is embodied within an air powered abrading tool having a rotary abrading member powered by an incoming flow of air which also serves to remove the resulting dust particles from the work surface.

A domed housing of the present device houses a turbine for rotation by an incoming flow of air with the turbine wheel having shaped fins thereon. Turbine rotation powers the abrading element via a gear reduction drive within said housing. The output shaft of the gear reduction assembly carries the abrading component with the latter rotating within the lower end of the domed housing. A continuous airflow passing peripherally about the abrading component, removes dust particles from the grinding surface with the airflow subsequently passing through the turbine as earlier mentioned.

An important object of the present invention is to provide an abrading tool for convenient use on large upright surfaces, such as for example, the walls of a building structure. Existing tools do not lend themselves to the surfacing of large wall areas as above noted. The finishing of such wall surfaces is largely done by hand as existing equipment is either too awkward for such use or is too small for efficient use. The absence of an electrical motor adjacent the rotating abrading disc or other heavy components permits the present invention to be moved along wall surfaces while manually supported by the machine operator. Large wall surfaces may accordingly be efficiently surfaced.

Another important object of the present invention is the utilization of the airflow, passing through the device, to remove dust particles resulting from abrading. While some grinding devices have attached dust pick-up means such an appendage contributes to the overall bulk of the prior art tool making it even less suitable for hand held grinding of large planar surfaces.

An additional object of the instant invention is to provide a lightweight, highly maneuverable unit highly suitable for use by a workman in the finishing of large surface areas such as walls, floors and ceilings. Customary practice involves the hand sanding of walls and ceilings particularly at the abutting edges of wallboard or edges of similar sheathing material. Considerable time is spent in preparing such wall surfaces for painting and includes both the grinding task and the cleaning of dust particles subsequent to painting of the walls. The lightweight nature of the present device permits use of a sizeable abrading disc. For example, the housing may be pivotally mounted at the end of a rigid conduit member with the latter serving as a handle for the device.

In use the housing closely overlies the surface being treated with a flexible skirt extending about the housing perimeter intermediate the perimeter and the surface. An area of reduced air pressure about the present grinding disc contributes to the ease with which the present device may be used on an upright wall surface.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a side elevational view of the present abrading device with the housing thereof broken away substantially along a vertical medial plane,

FIG. 2 is a horizontal sectional view taken downwardly along irregular line 2 -- 2 of FIG. 1,

FIG. 3 is a plan view of the air driven turbine removed from the device,

FIG. 4 is an enlarged, detail section taken along line 4 -- 4 of FIG. 1, and

FIG. 5 is a view showing a typical use of the abrading device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With continuing reference to the accompanying drawings wherein applied reference numerals indicate parts similarly identified in the following specification, the reference numeral 1 indicates a dome shaped housing having a detachable lower skirt section at 2.

Centrally of the housing 1, as best seen in FIG. 4, is a universal socket 4 for reception of a ball shaped conduit member at 5, said universal socket being defined by a boss 6 formed integral with housing 1. In bolted attachment with said boss for retention of the ball shaped member 5 is a cap plate 7 apertured at 7A so as to retain member 5 for movable engagement with said boss. Fasteners 8 extend through the plate 7 and a gasket 9 terminating in threaded engagement with the boss.

The ball member 5 is of hollow construction and formed at the end of a tubular member 10 which additionally serves as a hand held support for the device. As shown in FIG. 5 the elongate support 10 may be of considerable length for purposes of convenience. Also in FIG. 5 a flexible conduit is indicated at 11 which is in communication with member 10 and a vacuum source not shown.

With attention again in FIG. 4, a centrally disposed collar 12 depends from boss 6 to constitute a carrier for upper and lower pairs of bearings indicated at 13 and 14. Carried intermediate the opposing races of said upper and lower bearings is an annulus 15 of a turbine indicated generally at 16. Said annulus is integral with the innermost ends of a multitude of fins each indicated at 17 with the turbine additionally including a circular, planar base 18 having a central opening 18A therein. Lock nuts at 19 retain the bearing races 14 in place.

The turbine 16, journalled on bearings 13-14, is freely rotatable about stationary collar 12 with such rotary movement resulting from a converging flow of air generally parallel to base 18 and indicated by applied arrows in FIG. 1. Rotation of the turbine, via means later described, drives an abrading disc D at a reduced rotational speed.

A gear reduction drive is indicated generally at 20 having a pinion gear 21 driven by the turbine by means of a hollow shaft 22 journalled within a bearing 24. A flange at 22A is in attachment with base 18 of the turbine to complete the driving connection between the turbine base 18 and pinion gear 21. Said flange additionally serves to block an axial airflow. Pinion 21 is housed in a gear case 23 of the reduction drive. Bearings at 25, 26 receive a spindle at 27 the latter carrying transmission gears 28 and 29.

An output shaft is indicated at 30, journalled within a bearing 31 on the lower wall of the gear case 23, which shaft carries a final gear 34 of the reduction drive. The upper end of a shaft 30 is coaxially journalled within hollow shaft 22 which in operation rotates in the same direction but of course at a higher speed. The hollow shaft 22 is desirably provided with an insertable internal bearing sleeve of the self-lubricating type material.

The reduction drive 20, housed within the gear case 23, includes an upper wall indicated at 32 which extends outwardly for removable attachment at 33 to the housings lower section 2. The wall 32 is provided with a series of openings 32A for passage of incoming air and the dust particles carried thereby. That portion of the wall comprising part of gear case 23 is solid to prevent entry of foreign matter into the gear case.

For directing incoming air over the work surface and past the periphery of the abrading disc D I provide a circular air barrier 35 radially spaced from said disc. The barrier is of a semi-rigid plastic material normally having its lower edge 35A in closely spaced relationship to the work surface. For attaching said barrier to the housing structure 2 a ring member at 36 is threaded at 37 for screwed engagement with cooperating threads 38 on the housing skirt section 2. The barrier 35 accordingly acts to restrict somewhat the airflow entering the housing to effect a reduced air pressure within same and especially over that portion of the work surface circumjacent the disc D.

With attention to FIGS. 1 and 2 it will be seen that the airflow is upwardly through the large apertures 32A in the wall 32 and thence outwardly for passage around the periphery of the circular turbine base 18. Clearance at 40 in FIG. 1 between the curved edges of the fins 17 and the inner surface of the housing 1 constitutes an air passageway for distribution of the airflow upwardly along each fin 17. The source of reduced air pressure, in communication with the housing interior via the tubular member 10 and collar 12, exhausts air from a central area at 41 of the turbine. The airflow is generally horizontal, as viewed in FIG. 1 and with additional attention to FIG. 3 it will be seen that clockwise rotation is thereby imparted to the turbine 16. As earlier described turbine rotation is imparted to shaft 22 via the flange 22A thereon and thence to the gear reduction drive. The speed of disc rotation will be largely determined by the negative pressure source, the surface being worked on and, obviously, the gear reduction drive ratio.

In operation the conduit member 10 may serve as a hand hold for the device with its universal attachment to the housing permitting relative movement therebetween as the abrading device is moved along a work surface.

The reduced air pressure within the housing acts upon that annularly shaped area circumjacent the periphery of disc D to urge the device into surface contact. This feature in conjunction with components of lightweight materials provides a highly maneuverable device applicable to the treating of all types of wall surfaces and like planar surfaces of other large structures. The surface so treated is both smooth and clean for finishing as by painting.

The ring 36 may be adjusted upon the threads 38 of housing section 2 to space the lower terminus 35A of the barrier 35 from the work surface to best accomplish the objective of particle removal. It will be apparent that in use the barrier 35 will not at all times be uniformly spaced from the work surface as some slight tipping of the device will occur.

For regulating the flow of incoming air, in a convenient manner, it is desirable that the tubular member 10 be provided with an air inlet with manually adjustable closure means at 42 disposed thereover. The operator may accordingly regulate or stop operation of the abrading device while permitting the source of reduced air pressure to continue operation. Additionally, the housing 1 may be provided with at least one port having a positionable closure plate mounted thereover for permitting a regulated flow into said housing with a resultant lessening of negative air pressure in that area circumjacent disc D. The flow of incoming air through said last mentioned area would accordingly be reduced.

While I have shown but one embodiment of the invention it will be apparent to those skilled in the art that the invention may be embodied still otherwise without departing from the spirit and scope of the invention.

Claims

Having thus described the invention what is desired to be secured under a Letters Patent is:

1. An air driven abrading device for use on both upright and horizontal surfaces, said device comprising,

a housing structure in communication with a source of reduced air pressure,

a turbine journalled within said housing and adapted to receive a centripetal flow of air to drive same,

means included within said housing structure for communicating the central area of the turbine with the source of reduced air pressure,

a gear reduction drive powered by said turbine and in driving connection with an abrading disc, and

an air barrier carried by said housing structure circumjacent said disc with the lower terminus of said barrier in closely spaced relationship to the work surface directing a restricted airflow past the disc periphery for the pick up of dust particles.

2. An air driven abrading device as claimed in claim 1 wherein said turbine includes a base, fins disposed on said base and extending outwardly from the turbine center, said fins curving outwardly in the direction of rotation of the turbine and acted upon by an airflow traveling in a direction generally parallel to the turbine base.

3. An air driven abrading device as claimed in claim 1 wherein said housing is of domed configuration and includes universal socket means centrally disposed for the reception of a conduit end member.

4. An air driven abrading device as claimed in claim 1 wherein said turbine is operatively coupled to said gear reduction drive by a tubular shaft, said gear reduction drive including an output shaft journalled for a portion of its length within said tubular shaft.

5. An air driven abrading device as claimed in claim 1 wherein said air barrier is adjustably mounted on said mounting structure for adjustable movement toward and away from a work surface for the regulation of airflow into said housing.

6. An air driven abrading device as claimed in claim 2 wherein said housing is of domed configuration and includes universal socket means centrally disposed for the reception of a conduit end member, said air barrier adjustably mounted on said housing structure for adjustable movement toward and away from a work surface for the regulation of airflow into said housing.

7. A air driven abrading device as claimed in claim 6 wherein said turbine is operatively coupled to said gear reduction drive by a tubular shaft, said gear reduction drive including an output shaft journalled for a portion of its length within said tubular shaft.