US2255939A - Screen - Google Patents

Description

p 1941- G. A. OVERSTROM ET AL 2,255,939

SCREEN Filed Feb. 25, 1939 38 GUSTAVE A.OVERSTROM, GEORG: OVERSTROM, 22 CONRAD OVERSTROM, my. 6' BYQZM- Patented Sept. 16, 1941 SCREEN Gustave A. Overstrom and George Overstrom, Los Angeles, and Conrad Overstrom, Altadena,

Calif.

Application February 25, 1939, Serial No. 258,538

2 Claims.

An object of the invention therefore is to provide an improved screen having resilient supporting means to support the screen cloth from the deck struts.

Another object of the invention is to provide an improved strut construction for carrying a resilient strip adapted to support a screen cloth.

Still a further object of the invention is to provide a simple but improved form of resilient rubber strip support particularly adapted for screens.

Still a further object of the invention is to provide an improved form of resilient rubber strip for resiliently supporting a screen cloth from struts of the screen deck.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawing,

Fig. 1 is a side elevational view of a screen incorporating the novel features of our invention;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1 looking in the direction of the arrows, with parts omitted in the interest of clearness;

Fig. 3 is an enlarged detail view showing the resilient mounting means of our invention; and

Figs. 4, 5, 6, 7 and 8 are views similar to Fig. 3 showing modified forms of the resilient supporting means comprising our invention.

Referring particularly to Figs. 1 and 2 of the drawing, it will be seen that the screen of our invention comprises a main supporting frame ||l upon which is mounted a deck II which is resiliently supported from the main frame I at its rear end by a pair of composite coil spring resilient supports one of which is seen at l2 and at its forward end by a pair of leaf spring cantilever supports one of which is seen at l3. It will be evident that there will be one of each of the supports l2 and I3 on each side of the deck I I.

Vibratory motion may be imparted to the deck H by any desired means such as an unbalanced revolving pulley l4 which is mounted upon the deck I by appropriate supporting bracket means l5 which provides a journal bearing for the shaft I6 of said unbalanced pulley I4. The pulley I4 is driven from an electric motor H by means of a belt I8, said motor |1 being supported upon platform l9 carried by stand 20 forming a part of the main frame It).

The deck II is formed of a pair of spaced side channels 2|, 2| which are connected together by appropriate end cross-pieces.

As illustrated in Fig. 2 of the drawing, the deck II also includes a plurality of longitudinally extending supporting struts 22 which are supported on the above mentioned end cross-pieces. It is to be distinctly understood that the struts 22 may run transversely between the side channels 2| in-, stead of running longitudinally or struts may be provided running both longitudinally and transversely. This provides for both longitudinal and transverse support fora screen cloth 23 carried by said deck, the lateral edges of which are attached to the channels 2|, 2| as by attaching end tensioning means 24, 24 which may take the form disclosed and claimed in the patent to Gustave A. Overstrom for Stretching apparatus for screen cloth, No. 2,136,950, granted November 15, 1938.

Also if desired the deck may be provided with means to attach and stretch the screen cloth 23 adjacent the feed and discharge edges thereof. To provide a very effective resilient support for the screen cloth 23 which is of simple construction and is particularly adapted to remain in place during renewal, removal or tensioning of the screen cloth, we provide resilient supporting means 25 which, in its preferred form, is illustrated in detail in Fig. 3 of the drawing. Mounted upon the top of each strut 22, which is in the form of a T-bar, there is welded as at 32, 32 a channel 26 which extends longitudinally along the top of said T-bar 22. Th channel 26 is formed by bending the sides thereof to form up- Wardly extending side walls 21, 21, the interior surfaces of which slope upwardly and inwardly, that is, said inner walls 21, 21 converge from the bottom upwardly so that they form a groove having a Width which increases from the top downwardly or, as otherwise expressed, is dovetailed, as viewed in cross-section. The channel 26 therefore forms an elongated groove which receives a strip 28 of resilient material which is preferably of preformed configuration corresponding to that illustrated in Fig. 3 of the drawing. That is, the strip 28, as viewed in crosssection, has a dovetailed bottom portion 29 having longitudinally extending side surfaces which are in intimate contact with the interior surfaces 21 of the channel 26. The top portion 3|] of the strip 28 is preferably rounded where it contacts the screen cloth 23.

As clearly illustrated in Fig. 3 of the drawing, the upper edges of the side walls 21 may be completely covered by the rub-ber strip 28 in that grooves 3|, 3| are formed on opposite sides of said strip 28 to receive said top edges of the side walls 21.

It has also been found in practice that-the strip 28 need not be exactly preformed butif made of soft rubber, as it preferably is, the bottom portion 29 will, of course, be required to assume the dovetailed shape by making it larger than the groove formed by the channel 28. It is of particular importance to have this interlocking dovetailed relation between the groove forming channel 26 and the strip 28 because this V the rubber stripj36. v a v It is to be understood that any form of the prevents their separation even though the screen cloth 23is removed or is adjusted as to tension. In this connection it has been found in practice that where a rubber tube is merelyplaced freely in a slot there is a great tendency for the strips to become lost during transportation of the appa ratus'and to come out of the slots during tension of the screen cloth due to the tendency of the screen cloth to roll the strip outof the slot when the tensioning is effected. {Both ofthese objectionable features have been overcome by the structure of our invention.

As was previously pointed out, the resilient supporting means above defined may beemployed tosupport the screen cloth 23 by being applied to' longitudinally extending supporting members orstruts '22 only, or to transversely extending supporting members or struts only, or to both longitudinallyextending and transversely extend ing-struts or supports.

7 In Fig. 4 of the drawing, there is illustrated a supporting structure which is a slight modification of that-of Fig. '3. The diiferences are I obvious and lie principally in that the channel 83 does not have a fiat'bottom but'a curved bottom and there is more welding seenat 34, 34 employed in attaching said channel 33 to the strut 22i The rubber strip 35 is preformed and may belof slightly heavier construction than the strip'2'8. 7 In Fig. 5 ofthe" drawing we have illustrated a different form of .rubberstrip 36 applied to the supporting structure of Fig. 3. In this form the strip 36 is trapezoidal in cross-section and has a substantially flat top contacting area indirect contact with the screen cloth 23. This form of the strip -36 is, of course, simpler than the other forms and therefore less expensive.

' In Fig.6of the drawingwe have shown another form of supportfor the strip 36.; this form a very simple channel'is made by merely welding upwardly, extending and inwardly sloping side plates, 31 to the top of the T-strut 22 by welds 38, 38 along the bottom edges thereof. In Fig. 7' of the drawing wehave provided a different formxof strutor support 122 which, .it will-be understood, is the substitute for the struts or supports 22. This strut 'I22 is essentially in I the form-of a-rail having a groove 38' formed in thetop thereof which is dovetailed or, in other words; formed substantially the same shape as groove: as above described in connection withthe support of Fig. 3. It is, of course, evident that this strut or support I22 is a one-piece unitary structure and has the advantages of extreme rigidity realized from this type of construction.

- In Fig. "8 of the drawing we haveillustrated still another form of strut or support 222 which is in the form of aninverted' T-member to the upper end of the central web of which there is Welded a pair of longitudinally extending Z- shaped strips 39, "39 welded thereto at 40, 4!!" which strips cooperate with said central web of the strut .222 to form a groove ll similar in shape clusive. .endwise but we prefer to make them of rubber sufiiciently soft that they may be squeezed by 7 strut and groove forming mechanism associated V therewith, such as illustrated in Figs. 3 to 8, inclusive, may be employed with any of the various'forrns of the resilient rubber strips. As an illustration the rubber strip 30 disclosed in Fig. 3 may be employed with the supporting struts and channels disclosed in Figs. 4 to 8, in-

The strips may be slid into the grooves hand laterallyintothe grooves and also readily pulled laterally out of the grooves manually.

It is evident that any of the rubber strips when received by the groove formed supports will pro- .vide a dovetailed interlocking connection therewith thus insuring that the rubber strip will remain in place even though the screen cloth 23 is removed, or even though it is'slid over the supporting surface of the rubber strip with appreciable friction; This, of course, insures against loss of the resilient supporting strips and further insures again'stth'eir being displaced durscope of the invention as defined by the claims hereto appended, and wetherefore wish not to be restricted to the precise construction herein disclosed. 7

Having thus described and shownan embodi-,

ment' of our invention, w'hatwe desire to secure by Letters Patent. of the United Statesis:

'1. A resilient support fora screen cloth comprising a screen frame including a. strut having an elongated dovetailed groove formed by spaced apart upwardly and inwardly sloping substantially continuouslyfiat side walls which extend substantially continuously from the bottom of said groove to the'top' thereof, and a resilient strip having a preformed bottom formed by slop ing side walls which when in said. groove have intimate contact with said side walls thereof,

the top of said strip extending above the side .walls and being formed curved to "provide an extended area adapted to bear against and supto that above described in connection with Fig.

3of the drawing' This construction is a simple method of using an inverted T-st rut and providingthe desired dovetailed groove to receive port a screen cloth.

2. A. resilient support'for a screen clothxcomprising a screen frame "including a strut having an elongated dovetailed groove formed byspaced apart upwardly and inwardly sloping substantially continuously fiatside walls which extend substantially continuously from the'bottom of said groove to the 'top thereof; and .a resilient strip having a preformedbottom formed by slop;

ing side walls which when in said' groove-have intimate contact with said side walls thereof the top of said strip extending above the side walls and' being formed" to provide an extended area adaptedto bear; against and support a screen cloth.- GUS TAVE A."ovERsTRoM.-

I GEORGE OVERS'IROM.

CONRAD OVER-STROMf

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