US2119813A - Abrading apparatus - Google Patents

Description

June 1, 1938- EKE-EFER v 2,119,8 I

May is, 1936 7 Original Filed Patented June 7, 1938 UNITED STATES ABRADING APPARATUS Walter L. Keefer, Hagerstown, Md., assignor to Pangborn Corporation, Hagerstown, Md., a corporation of Maryland Original application May 13, 1936, Serial No.

79.559. Divided and this application April 6, 1938, Serial No. 200,521

11 Claims.

This invention relates to abrading apparatus and more particularly to mechanical apparatus for propelling abrasives at abrading velocities.

Abrasive throwing wheels having bladed rotors have been known in the art for many years, and althoughthey are now going into rather wide use they are open to the objectionthat valuable time is lost changing blades. The blades of abrasive propelling rotors must be made removable, so that they may be replaced when they have worn out, and yet must be held so securely that they will resist the tremendous centrifugal force exerted when the wheel is operating.

The centrifugal abrading machines in use today are. open to the further disadvantage that theblades wear out rapidly, which entails high.

maintenance costs. The blades would have a reasonable life if the wear occurred uniformly throughout the width of their propelling surfaces, but it has been found that through casting or other inaccuracies, substantially all of the abrasive admitted to each blade will take a course in a localized stream thereover when the blades are first placed in use, and as time goes on the bladeswill be deeply worn in this particular region with the result that all of the abrasive traversing the blade will take this course, producing rapid break-down of the blade.

It is a primary object of this invention to pro= vide an abrading machine blade assembly that securely holds the blades in place and yet permits them to be removed and replaced in a minimum of time.

It is a further important object of the inventionto provide a novel blade assembly for abrading machines that will hold all of the blades securely in place while the machine is operating, will permit easy and rapid removaland replacement of theblades when they wear out and which will also permit the blades to be removed and replaced in the machine in a diiferent relationship to present different surfaces to the abrasive when certain of their surfaces have become worn.

'A further object is to provide,.in an abrading machine having a bladed rotor for propelling the abrasive, a novel blade mounting assembly which will securely hold the blades in place and will not work loose during operation of the machine, and

which will permit the blades to be quickly and easily removed from the rotor.

Afurther object is to refine and improve certain detailed features of centrifugal abrading machines, and this application constitutes a. division of my co-pending applicationserial No. 79,559, died May 13, 1936.

Further objects of the invention will become apparent as the specification proceeds in connection with the annexed drawing, and from the appended claims. I

In the drawing:

Figure 1 is a side elevational view of an abrasive propelling rotor equipped with the blade assembly of this -invention, with parts thereof broken away in order to more clearly illustrate the structure involved. 1

Figure 2 is a view looking at the wheel of Figure 1 from the right-hand end of that figure, with parts broken away for clarityof illustration.

Figure 3 is an enlarged fragmental sectional view illustrating the manner in which the blades cooperate with their locking screws.

Figure 4 is an isometric view of one of the blades of the invention. I

With continued reference to the drawing. 3

wherein like reference characters have been employed'to designate like parts throughout the several views thereof, the rotor is designated at R, and it is rigidly secured to a shaft l0. Shaft I0 is mounted for rotation in any desired bearing assembly (not shown) and rotor R carries a plurality of abrasive propelling blades B. Blades B terminate short of the center of the rotor to define-a central abrasive admitting space in which an abrasive feeding device F is supported for feeding a stream 'ofabrasive over the inner ends of blades B. v

The feed device will-be presently described, and it efiectsdirectional discharge of the abrasive thrown from the wheel, but it is to be understood that insofar as the blades and blade mounting are concerned, the invention is not limited to a particular feeding device but maybe applied to any type of abrading'machine. For instance. feeding device F may assume the form of a pipe or achute for dumping the abrasive into the central space and efiecting a three hundred and sixty degree discharge of the abrasive. Also. blades B have been shown as four in number, but it is to be understood that the invention is applicable to rotors having more or less than four blades. I

Secured tothe face of rotor R, by a. plurality of counter-sunk screws l I, are four symmetrically arranged plates l2. The radial edges of plates I2 are'provided with bevelled faces 13, and the adjacent edges of each pair of plates define a of plates 2. The inclined faces I of blades B 2| when they are turned home it is unnecessary merge into abrasive propelling surfaces it provided on each side of the blade. As seen in Figure 1, inclined faces I! merge with plates l2 in-a region spaced from their propelling surfaces It, with the result that the abrasive moving outwardly over surfaces I6 is maintained out of abrading contact with plates l2, which are permanent parts of the machine. The free edges of blades B are each provided'with a flange or ridge ii to confine the outwardly surfaces It.

'Ihe blades are accordingly mounted for guided movement toward and away from the axis of the rotor, and although grooves ll, which constitute the guideways, are shown r s being disposed substantially radially, it is to be understood that they may be inclined forwardly or rearwardly with respect to the direction of rotation if desired without departing from the spirit of the invention.

, The means employed for restraining blades B- against outward movement preferably takes the form of a screw l8, threaded into rotor R adjacent the outer end of each guideway ll. Each screw it is provided with a hex head I! which projects into a recess 2| in the base of each blade B and cooperates with a wall 22-thereof to positively arrest outward movement 'of' the blades. The flat sides of head I! provide a large gearing surface for wall 22 and also prevent screws II from working loose in operation.

Referring to Figures 2 and 3, wall 22 and its opposite wall are spaced apart. a distance which is greater than the greatest diameter of hex heads II, with the result that blades B can he slipped into place in grooves It and screws II turned up until they assume the position shown in Fig.- Y ure 3. Blades B may then be pulled outwardly until their walls 22 abut one of the flat sides of hex heads I! as seen in Figure 3, or they may be left in their inner positions because when the rotor is started centrifugal force will bring them into cooperating relationship to screws ii. The inherent friction present between blades 13 and their guides may be relied upon to restrain them against inward movement when the rotor is subsequently stopped, but if desired, spring means, taking the form of a split resilient ring, encircling feed device F and engaging the inner ends ofthe blades, may be used to positively hold them in engagement with screws l8.

Although screws it may be provided with any suitable formation to permit them to be turned home with a wrench, they are preferably internally formed with a hex socket 23 in order that the screws may be so dimensioned as to lie flush with the rear surface of rotor R when they are turned home. It isnot necessary to turn screws l2 into a final position where a flat side of hex head i9 will be disposed in parallelism with wall 22 of recess 2| because the forces set up by rotation of the wheel-will cause the blades to work screws it into the relationship shown in -Figures 2 and 3. Screws it are preferably designed.

r however, so that the faces of socket}! and hex I head I9 are disposed in registry, as seen in Figure 3, with the result that the relationship of the surfaces of hex head I! to wall 22 of blade B may be determined by merely glancing at socket 23. Also, if a wrench of the type shownin dotted lines in Figure, 3 is used, the relationship of the parts will-bedirectly indicated by the position of the wrench handle.

If, however, the heads of screws II are so dimensioned as to seat in the bottoms of recesses moving abrasive to to take any particular precaution in installing the blades because screws I! are thus automatically stopped in approximately proper position and will assume proper position when the wheel is started.

As seen in the drawing, when the screws are turned home a clearance exists between their shoulders and the parts of cesses 2|.

Although a particular form of locking 8586!!!! bly has been illustrated, it is to be understood that other forms of locking devices, which themselves are locked by the blades, may be used without departingjrom the spirit of this invention. For instance, instead of using screws it, simple pins, having formations at their ends for interlocking engagement with the blades when the latter are slid outwardly, may be used if desired. Moreover, hex head I! may be made with more or less than six sides if desired. For instance, square headed screws may be used if desired.

blades B defining re- Referring now to Figure 4, each blade B is provided with two recesses 2| in its base and it is therefore symmetrical in form. The base of the blade also may or may not be cored out, as at If an uncored blade is employed, it is to be understood that a single recess 2|, located mid-way between the ends of the blade, may be used. Also,

two screws It may be employed to hold each blade of the present invention in place, but it has been found that one screw is adequate, and

- v the term a screw or a securing device" as employed in the appended claims is intended to embrace the use of one or more, screws It or their equivalents.

As seen in Figure 1, feeding device F comprises a cylindrical member 26 having an abrasive discharge opening 21 and a plurality of external teeth having faces 29 and 3|. Cylindrical member,26 is supported for adjustable rocking movement about the axis of the rotor upon a support S. Cylindrical member 28 is provided with a pair of studs 33, which project through a pair of arm-- ately-shaped openings 24 provided in support S. A pair of nuts are threaded on studs 32 and are operable to clamp feed device F to support S in any desired adjusted position, for varying the direction of discharge from the wheel.

support 8 is provided with a spout portion 21 assembly with a rotor having but a single disc to which plates l2 are secured, the invention is clearly applicable to. rotors having two discs as the guideway and/or the blade locking assembly the diameter of said portion of said locking memmay be duplicated on each disc.

claims are therefore intended to be embracedtherein.

What is claimed and desired to be secured by United States Letters Patent is:

,1. For use in an abrading machine, a rotor having at least one guide means provided thereon,

an abrasivepropelling blade mounted in said uide means, an elongated member extending through said rotor and having a locking portion which is movable 'into the path of a surface of said blade when said member is rotated about its axis, said locking portion of said member being soshapedthat when said blade surface is engaged therewith said member cannot be rotated about its axis and is thereby maintained in looking position.

2. For use in an abrading machine, a rotor having at least one outwardly extending guideway provided thereon, an abrasive propelling blade mounted for sliding movement in said'guideway, said blade having at least one outwardly facing abutment wall provided thereon, alocking member threaded into said rotor and movable into the path of movement of said blade for restraining the same against outward movement in response to centrifugal force, said locking member having a portion adapted for interlocking engagement with said abutment wall of said-blade,

whereby said blade is operable to restrain said locking member against turning movement when said rotor is in operation.

'3. The rotor construction described in claim 5. The rotor construction described in claim 2,

wherein said locking member comprises a screw having at one end a fiat sided head whose greatest diameter is less than that of the body of the screw, and at the other end an internal wrench receiving socket.

6. The rotor construction described in claim 2, wherein said blade is provided with aninwardly facing abutment wall located outwardly of said outwardlyfacing abutment wall for cooperation with said locking member to prevent inward movement of said blade, said abutment walls being spaced apart a distance at least as great as her. 1

7. In an abradingmachine, a rotor mounted for rotation, an abrasive propelling blade operably associated with said rotor and having a. Y

propelling surface facing forwardly with respect to the direction of rotation and a propelling surface facing rearwardly with respect to the direction of rotation, said first-named propelling surface being operable to pick-up the abrasive and discharge it at an abrading velocity, said blade being substantially symmetrical and having means associated. therewith for selectively secur ing it to said rotor with said first-named or said 'second-namedpropelling surface facing forwardly with'respect to the direction of rotation, whereby said blade may be reversed when one of its propelling surfaces has become worn to a. predetermined degree..

- 8. The rotor construction described in claim '1 wherein said means for securing said blade to said rotor is operable to cooperate with a single side edge of,. and support said blade upon said rotor with either of said propelling surfaces facing forwardly, said blade being reversible endportion formed along one of its side edges for securing it to'a" rotor, said blade having a. flange formed along the other of its side edges, for con-'- fining abrasive to bothof said abrasive propelling surfaces.

in a direction parallel to the major axis of the blade.

' 10. The blade constru'dtion described in claim 9, wherein said base portion is provided with at least one recess facing away from the side edge of said blade and providing a pair of walls spacedv apart 11. For use in an abrading machine, a rotor having at least one outwardly extending guldeway provided thereon, an abrasive propelling blade mounted for sliding movement in said "guideway and having an abutment face, and means supported by said rotor and operable to engage said abutment face and restrain said blade against removal from said guideway when it is disposed in a locking position, and to allow said blade to be removed when it is disposed in a release position,

- said abutment face and said locking means being so shaped that when they are engaged said locking means cannot be moved into non-locking position, whereby said blade is operable to maintain said means .in. blade locking position when said rotor is in operation, s'aid guideways comprising a pair of substantial radial outwardly ex- WALTER L. cs

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