US1859784A

US1859784A - Method of making screen plates

Info

Publication number: US1859784A
Application number: US479649A
Authority: US
Inventors: Walter E Mcmurray
Original assignee: Clearfield Machine Co
Current assignee: Clearfield Machine Co
Priority date: 1930-09-04
Filing date: 1930-09-04
Publication date: 1932-05-24
Anticipated expiration: 1949-05-24

Description

May 24, 1932. w. E. M MURRAY METHOD OF MAKING SCREEN PLATES Filed Sept. 4, 1930 5 Sheets-Sheet 1 Suva/" 6oz lV/IL TEE E. M MMF/EAY gaym zm w. E. M MURRAY 1,859,784

METHOD OF- MAKING SCREEN PLATES Filed Sept, 4, 1950 3 Sheets-Sheet 3 m w 5% m/y////v/// W NP mm awweutoz Patented May 24, 1932 UNITED STATES PATENT. OFFICE \VALTER E. MCMURRAY; OF CLEARFIELD, PENNSYLVANIA, ASSIGNOR T0 CLEARFIELD MACHINE COMPANY, OF GLEARFIELD, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA METHOD MAKING SCREEN PLATES This invention relates more especially to screen plates 1n WlllCh the screening slots are of arcuate form and concentrically arrangedwith respect to a common axis of revolution.

The primary object of my invention is to provide an improved. method for constructing screen plates of this character for the pur- I vide an improved method for constructing.

segmental screen plates from predetermined lengths of straight bars of proper form, said method contemplating the separate bending of said straight bar lengths which after flexure and assembling are rigidly united into a simple unitary structure.

In the drawings which represent a preferred embodiment of my invention as ap-' plied to a screen for dry pans in rotary mills, Figure 1 is a top plan view of a screen plate constructed in accordance with the principle of this invention.

Figure '2 is a top plan View of the segmental supporting frame therefor with the screen plate in position, portions offsaid screen plate being broken away.

Figure 3 is an enlarged radial section of the screen plate and supporting frame on the line'3-3, of Figure 2. v

Figure 4 is an enlarged endelevation of Figure 2. i F

Figure 5 is a top plan view of a preferred form of jig or former within which the straight bars or blanks are curved or bowed while they are being assembled in their' screen-forming arrangement some of the bars being shown in assembly position and another one shown in process of being bowed and positioned. v I J Figure 6 is an enlarged end elevation of the Application filed September 4, 1930. Serial No. 479,649.

jig shown in Figure 5 with the screen bars 'to be inserted into the bending and assembling jig. 7 Figures 9, 10 and 11 are enlarged fragmentary representations of radial sections of the assembled screen bars showing different forms of welding which may be used'advantagcously for joining the screen bars into a unitary structure. 7 I a In Figure 1 of the drawings is shown an illustrative embodiment of a segmental screen plate to the construction of which my improved method may be adapted. As shown, this screen plate comprises a series of arcuate screen bars 1 which are graded in length and concentrically arranged with their opposite ends in radial alinement, said arcuate bars being rigidly united along the radial lines 2, 3, 4;, 5, and 6 by welding opera tions as hereinafter described. In this way. the screen plate is provided with radial bars which may be arranged to correspond with the similarly arranged bars of a supporting frame by which it is to be carried. At angularly-spaced intervals around the outer and inner peripheries of the screen plate, inserts are welded in between some of the arcuate bars 1 in such a way as to form

attachment bosses

7 and 8. All of the bosses thus formed are adapted to be arranged above and to be connected to similarly arranged bosses with which said supporting frame is provided." As shown in Figures 3 and 4, the screen bars 1 are provided with inverted cuneiform cross sections which provide downwardly enlarged intervening slots As .shown in Figures 2, 3 and 4. the above-described segment, screen plate is adapted tobe seated in a rotary supporting frame segment which. comprises inner and outer

arcuate bars

9 and 10 and insaid arcuate bars being provided with

annular seats

16 and 17 for supporting the inner and outer arcuate edges of the screen plate.

It will be seen that when the screen plate is properly positioned on the arcuate supporting'framc, the radial bars of said screen plate which-are formed along the radial lines 2, 3,

4, 5 and 6, will be arranged over and rest upon .the upper edges .of the radial bars .11, .12, 13, 14 and 15 of the supportingframe segment. Said frame segment may be provided with apertured bosses 18, arranged respectively below the attachment bosses 7 of the screen plate and other apertured bosses 19 arranged 15 respectively below the attachment bosses 8 of said'screen-plate. Asindicatedin Figure 3 of the drawings, abolt;'2O may be'passed upwardly"through.each. of the apertured bosses 18"and 19 and have-their upper ends 0' threaded into tller-TGSPGCtiVG :attachment.

\ bosses 7 and 8- of the-screen plate." Suitable --uneans for manufacturing the screen-plate .describedabove;from straight bars of proper cross section and graded in length, "may be ggwprovidedas follows. "A-group of ','straight bars suitably'zgradedi in: lengths to'malre up thedesiredscreen :plate, isshown in Figure 8.

:;Referring now to Figures 5, 6- and 7gthe straight bars or blankszshown in'Figure 8,

" may be bent and assembled in aji such as that shownzin Figures 5, 6 :and 7. For this purpose, a heavy flatbase' plate 21 which is lon'ger andwi'der than the completed-screen plate, imay-be provided with a radial edge 22 85 withwhich the alined endszoftall'screen bars will register when saidscreenbars have their opposite ends in abutment with a radial strip or stop bar 23: which issecured to theiother ra'dial edge'of the base plate 21 by means of 10 bolts-2 lasshown in Figure 7.--Spaced in- :wardly fromthe radial edge 22 of the base #plate 21 and removably securedthereto bybolts 25,-as shown in Figure 6,'isa gagebar 26 which is providediwith a series of downand shape to permit the several straight bar sections or blanks to be driven endwise there-- through, said notches being uniformly spaced one from anothertocorrespon'd to the spacingo-f thearcuate screen'bars in the finished screen plate." Spacedinwardly from the stop bar'23, is a second gage bar 28 of exactly siinilar'form to'thegage-bar'26. Interposed between the

gage bars

26 and 28, are a plurali 'ity of laterally-spaced gage bars29, 30 and 31, similar inconstruction to the gage bars -'26 an d 28,andarrangerLinpairs as" shown in r Figure 5. All of thegage bars are removably secured to the base plate 21 so as to permit C3 thGTQIDOVELl of the finished screen plate after the several screen bars have been united into aunitary'structure in the manner to be pres.- ently explained. As each of said screen bars is tapped through one'after another of the notches" 27 ineach arcuately arranged series of said notches, the forward end of that screen bar is continually deflected into position to enter the notch next in front so that by the time it has come into abutment with the stop bar 23, it has become bowed into its arcuate form of the finished screen plate. It will be understood from this description that after all of the screen bars have been driven home with their forward ends alined against the radial stop-bar 23, their rear ends will also be in alinenient along theradial edge 22 of the base plate 21. Said bars are now assembled in position to be rigidly united into a unitary structure. For this purpose, I preferably employ any approved method of welding for uniting spaced bars of thischaracter, the necessary welding operations inthe present case beingperformed along the radial lines 2, 3, 4,5 and 6 w-lnchrespectively correeach of the radial lines 2, 3,4,5 and 6, the

adjacent spaces being filled by'the welding stock 33; If preferred, the intervening spaces between the neighboring bars may be completely filled with small separateamasses 34:

' of the welding stock as shown innFigure 10.

According to Figure 111,-the spaces intervening betweenstie'screen: bars 1 arezfilled by wedge-shaped blocks 35 which may be :brazed to the adjacent rods.

' While I have described a preferredanethod of procedure in respect to: cutting the straight screen bars in accurately gradedlengths so that when flexed' and positioned inproperly :spaced relation, their ends will-come into radial alinement to correspond with-the radial -ends 'of-the' finished segmental screen-plate,

45 wardly-enlarged-notches 27 of suitable size' the straightscreen bars may be'flexedandpositioned prlor to a cutt1ng-operat1on along either or both radial lines corresponding to the'ends 'of'the finished screen plate. Furthermore, I desire to have it understood. that the proper-lengths of-the. several screen bars may be determined by a cutting operation by a cutting torchHor other suitable means before the welding operation and while said screen bars are ;held in flexed position,1or the screen plate may be finished or by a trimming operation along its .radial edges after the welding operation is completed.

I claim: I 1. The method of constructingv segmental screen plates, which method. consists in cutting a plurality of straight barsin lengths corresponding respectively to. the lengths of said barsin a completed screen plate, in areaately bending said bars, in" arranging said bars in proper spaced relations corresponding to their relative positions in the completed screen plate by means of the bending operation, and finally in rigidly uniting said bars together at longitudinally spaced points.

2. The method of constructing segmental screen plates, which method consists in cutting a plurality of straight bars in lengths corresponding substantially to the lengths of the arcs formed by said bars in the completed screen plate, in bending said bars into their final arcuate form, and in assembling them in their final relative positions during the progress of the bending operation, and finally in permanently uniting said bars together.

3. The method of constructing segmental screen plates, which method consists in cutting a plurality of straight bars in lengths corresponding respectively to' the lengths of the arcs formed by said bars in the completed screen plate, in bending each of said bars into its final arcuate form under a stress less than that required to permanently distort it, and finally in permanently uniting said bars together while they are held in spaced flexed positions. 7

at. The method of constructing segmental screen plates, which method consists in cutting a plurality of straight bars in graded lengths corresponding respectively to the lengths of arcuate screen-bars in a segmental screen plate in bending said bars into concentric arcs while arranging them in equidistant positions between the inner and outer peripheries of the completed segmental screen plate, and finally, in permanently uniting said arcuate screen bars to form a unitary screen plate.

5. The method of constructing segmental screen plates, which method consists in cutting a plurality of straight bars in lengths corresponding respectively to the lengths of the arcuate bars in a segmental screen, in arcuately bending the longest of said bars while placing it in position to form the outer border of said segmental screen, in arcuately bending the shortest of said bars While placing it in position to form the inner border of said segmental screen, in bending the remaining bars in concentric arcs of graded lengths while placing them in equi-spaced positions between said inner and outer borders and with their opposite ends in radial alinement, and finally, in uniting the radiallyalined ends of said arcuate screen bars to form a unitary segmental screen plate.

6. The method of constructing segmental screen plates, which method consists in cut ting straight bars in graded lengths, in flexing said bars under insufficient stress to permanently distort them, and finally in welding said bars together to form a unitary segmental screen plate.

7. The method of constructing segmental screen plates, which method consists in cutting a plurality of straight bars in lengths corresponding respectively to the arcs occupied by said bars in a finished segmental screen plate, in flexing said straight bars to their proper arcuate forms while arranging them in the relatively spaced relations to be occupied by them in the completed screen plate, and in welding said screen bars together along radial lines; corresponding to the underlying bars of a supporting frame upon which the completed segmental screen plate is to be superimposed.

8. The method of constructing segmental screen plates, ting a plurality of straight bars in lengths corresponding respectively to the arcs of a finished segmental screen plate, in arcuately bending said straight bars while arrangwhich method consists in cuting them in suitably spaced concentric positions with their ends in radial alinement, and in Welding said arcuate screen bars together along lines and at places corresponding to the supporting surfaces of a supporting frame upon which the completed segmental screen plate is to be superimposed.

9. The method of constructing segmental screen plates, which method consists in flexing a plurality of straight screen bars of graded lengths and similar cross-section with corresponding surfaces disposed in a common plane, in arranging said screen bars in parallelly-spaced relations during the progress of the flexing operation, and in welding the flexed screen bars together in their grouped arrangement.