US2176497A - Apparatus for velocity particle-stream propagation - Google Patents

Description

oct. 97, 1999. w, A, HEX-r 2,176,497

APPARATUS FOR VELOCITY PARTICLE-STREAM PROPAGATION Filed Jan. ll, 1938 2 Sheets-Sheet 1 i' l i" 25 IN VENT OR.

Oct. 17, 1939. W. A. HExi- 2,176,497

APPARATUS FOR VELOCITY PARTICLE-STREAM PROPAGATION INVENT OR.

Patented Oct. 17, 1939 UNITED STATES PATENT OFFICE William A. Hext,

Application January 11,

2 Claims.

The present invention relates to velocity particle-stream propagation method and apparatus for use in the arts relating to surface treatment of materials.

An object of the invention is to provide a novel method of velocity stream propagation and further to provide apparatus for carrying out the method at extremely low power expenditures.

Another object of the invention is to provide means whereby abrasive particle material is eciently projected with surprisingly little wear on the parts of the apparatus.

Still further objects of the invention are the provision of a means and method for developing particle streams of Well controlled dimensions and readily controlled velocity.

A further object is to provide means to generate a ribbon-like velocity stream of varying density transversely of the stream for the purpose of .20 producing shaded eifects upon a surface treated by said stream.

These and other objects are attained by the method and means herein described and disclosed in the accompanying drawings in which:

.25 Fig. 1 is a side elevational view of a continuous velocity stream propagation device embodying the invention.

Fig. 2 is a front elevational View of the device of Fig. 1.

30 Fig. 3 is an enlarged View taken on line 3--3 of Fig. A1.

Fig. 4 is a view taken on line 4-4 of Fig. 3.

Fig'. ..i is a schematic view of a feed-regulator whereby the quantity of particle material through the device may be regulated.

Fig. 6 is a schematic View showing a modification of the velocity particle-stream propagation elements.

'Ihe method and apparatus of the invention 40 are applicable to the surface treatment of materials such as metals, glass, molded materials, wood, and other substances to which' particle streams may desirably be applied at suitable velocities for cutting, abrading, cleaning, frosting, and kindred operations with solid particle matter. It is also feasible to apply-liquid or freely iiuid plastic materials with the same essential stream propagating elements.

Heretofore, velocity particle streams have been developed using air pressure and various forms of no-zzles with an expenditure of considerable power for operation. This is commonly employed in sand or abrasive blast methods and also in .spraying of liquids. It is also known to utilize an impeller disc with blades, and means to feed.

Cincinnati, Ohio 1938, Serial No. 184,455

the particle material centrally of the impeller after the fashion of a centrifugal pump. These centrifugal type devices are in some respects superior to the pneumatic blast devices but are known to require very frequent renewal of the 1i' impeller blades because of the action of the abrasive material.

The disadvantages of the previously known clevices have been obviated by the present invention which consists in feeding the material to be handled between the proximate or contacting peripheries of two tread surfaces which travel at selected high speed so that the particles are momentarily gripped between said surfaces from which they are almost instantly accelerated to the velocity of the tread surfaces and are as quickly discharged in a thin ribbon-like stream midway between the treads. beyond the zone of contact of the treads.

The particle stream is generated Without back pressures and the spread of the stream in the direction of its thickness is gradual due to the absence of air pressure. The width of the particle stream is limited only by the Width of the cooperating treads employed, and it can be reduced by limiting the spread of the particle material on the feed side of the region of contact of said treads.

In the preferred form the treads are carried by axially parallel rollers suitably arranged to be rotated at a suiiiciently high speed to attain the necessary rate of surface travel of the treads.

'I'he rollers 8 and 9 are in the herein described embodiment operated by a single motor I2 with an extended rotor shaft I3 upon which roller 8 is fixed. Roller 9 is mounted on a shaft I4 supported in link member i which is pivoted at I6 to the base of a bracket piece Il. The shaft I4 is thus retained parallel to shaft I3, but is shiftable by the link I5. A tension device, comprising a stud I8 passing through vertical bracket arm I9 and the link I5, and a spring 20 abutting the said link and a thumb-nut 2l, Serves to yieldingly retain the treads I0 of rollers 8 and 9 in good tractional Contact with the selected size of particle material. The treads are thus operated at uniform speed by motor I2 due to the tractional force of the treads upon each other or upon the material feed between them.

The treads I0 may be of any suitable material such as composition, metal, or rubber. In the present form, treads I8 are rubber, having the outer peripheries 22 somewhat softer than the inner peripheries 23 so that the treads are very 55 securely retained on the rollers by their own tension. Portions 22 and 23 are schematically indicated in Fig. 3 and are the product of different degrees of curing of the treads. However, any other means may be used to secure treads of desired character to the rollers.

The rollers may be of any desired width, ranging from a fraction of an` inch up to any number of feet.

With the treads operating at uniform high speed and in the same direction at the zone or margin of yielding contact, the particle material to be projected is fed, preferably by gravity, between the treads in the direction of movement, i. e., in the general direction of a tangent which is common to both treads at the place of mutual contact. The particle material 24 is picked up by the pair of treads Il) in the contact zone I I where the velocity of the surface speed of the treads is imparted to the particles without much, if any, abrading action on the tread surfaces. The particles are accelerated to the speed of the treads instantaneously and are as quickly discharged at high speed in a particle-stream 243. The particle-stream 24! is naturally very thin and ribbon-like and does not spread to any great degree within a foot or so of the treads. Due to the absence of pneumatic pressures, there are no back-pressures involved in the particle-stream propagation and the spread of the stream increases gradually and without turbulence. Materials to be surface-treated with the particlestream are merely held in the path of the stream.

Any suitable means may be employed to provide a substantially even and uniform rate of feed of particle material 24 to the treads. As shown in Figs. 1 to 3 inclusive, the particle-stream propagation meansl may be mounted on a shelf-like bracket 25 so as to dispose the rollers and treads in an enclosing cabinet structure made up of sidewalls 23, a funnel-shaped bottom 2, a top wall 23, and a front 29. The front 29 has an inclined transparent window 3l) and a multislotted rubber curtain 3l.

Continuous feed and return apparatus is desirably provided for the stream propagation apparatus. This is provided by a gravity tube 3l which directs the particle material from the bottom 2l to 'an elevator conveyor system 32 which discharges the material into a hopper 33. The hopper 33 is provided with a tapered spout 34 with a controllable discharge slot 35. A shaft 33 traverses spout 34 and has a pair of arms 31 fixed thereon and disposed eXteriorly of the spout at the opposite ends thereof. A slide 3B operating in guides 3S has one edge parallel to the edges of discharge slot 35 while the opposite edge is tapered relative thereto. A handle crank 4E) is adjustable on a quadrant 4l and is xed on shaft 36 so that slide 38 may be positioned to control the effective width of slot 35 and also provide either a parallel sided or a tapering discharge opening. Below the spout 34 is a wedge-shaped feed nozzle 42 which receives the particle material from slot 35 and guides it to the mutual contact margin ll between the treads. The width of the lower end of nozzle 42 should be no greater than the width of treads I0 but it may be narrower if required in order to produce a correspondingly narrower particlestream 240.

In operating the device as thus described, the motor l2, which is desirably a variable speed motor, would be energized and the rollers 8 and 9 set in operation. The elevating conveyor would be then placed in operation, this` mechanism being driven by .a belt 43 from a separate power source (not shown). The operator would next adjust the size of slot opening 35, using crank 40 to move the slide 38.

If the particle material is an abrasive, such as carborundum, a quantity of the material is entered into the bottom funnel 27 and is carried to hopper 33 by the elevatingconveyor at an adjusted feed ratewhich can be accommodated by the rate of travel of treads Il). Articles to be treated are entered by the operator through the slotted curtain 3| at the front of the enclosing booth or housing and the work of the particle stream on the surface of the article is observed through transparent window 30.

The particle material is collected in the bottom funnel 21 and recirculated in the same fashion to produce a continuous velocity particle stream.

Adjustment of the speed of the treads and of the feed of material may be made to suit the character of Work to be done by the particle stream.

When the tapered edge of slide 38 governs the slot 35 the propagated velocity stream 240 is made progressively denser across the Width of the stream. This is advantageous in producing shaded frosting or etching on glass or kindred materials for artistic finishes thereon.

Mechanism for providing accurately controlled feed of the particle material is shown schematically in Fig. 5. This mechanism when used would be interposed either ahead of spout 34 or in lieu of said spout. The arrangement consists essentially of a wedge-shaped hopper 44 with one lip cut away as at 45 where the hopper discharges on a controlledly rotatable drum from which the particle material spills into a feed nozzle 46. A variable speed motor 4l operating through a suitable speed reducer 48 rotates the drum at a selected rate, thereby providing a proper distribution and rate of feed of particle material to the treads.

For operations requiring lesser velocity for the particle-stream, belts may be employed for treads in the propagating mechanism and the direction of the stream may be changed as desired. As shown schematically in Fig. 6, a belt 49 carried by pulleys 5B and 5l is driven by any power means operating on pulley 5U. A second belt 52 is carried by a pair of pulleys 53 which are supported on shafts carried by pairs of links 54. The links are pivoted at 55 on a threaded stud 5E which serves as a belt tightener for both of the belts Ywhen the stud is shifted longitudinally by nut 5l operating against a fixed support 58. A suitably arranged feed hopper 59 discharges the particle material between the treads at 6l! and the stream is projected at suitable velocity in a horizontal direction at 62.

The application of different materials fora wide variety of purposes may be effected by devices embodying the velocity stream propagation mechanism of the invention and the latter is not to be considered as `limited to the exact details of construction herein disclosed.

What is claimed is:

1. In a device of the class described the combination of a pair of endless belts, a pair of pulley assemblies supporting the respective belts in contacting relation through a generally L- shaped path whereby a downwardly extending feed entry way and a connected outwardly extending discharge delivery way are formed between the belts, means to bodily move one of the pulley assemblies toward the other whereby both belts are simultaneously tightened, and means to feed abrasive particle material into the downwardly extending way between the belts.

2. A device for propagating a ribbon-like velocity particle stream for producing shaded effects comprising a pair of tread members in yieldably contacting relation across the width thereof means to gravitationally feed particle material between the treads at the area of contact thereof including a hopper having a discharge slot substantially coextensive with the width of the treads and an adjustable member shiftable with relation to the slot to selectively modify the size and cross-sectional shape of the gravity particle stream, and means imparting uniform high speed motion to the treads whereby the gravity stream is accelerated and discharged in a ribbon-like stream of cross-sectionally varying density.

WILLIAM A. I-IEXT.

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