US2406272A

US2406272A - Roll screen assembly

Info

Publication number: US2406272A
Application number: US467923A
Authority: US
Inventors: Harold E Van Voorhees
Original assignee: Borg Warner Corp
Current assignee: Borg Warner Corp
Priority date: 1942-12-05
Filing date: 1942-12-05
Publication date: 1946-08-20
Anticipated expiration: 1963-08-20

Description

Aug. 20, 1946. H. 5; \(AN VOORHEES 2,406,272

ROLL scnnnn ASSEMBLY Filed Dec. 5, 1942 s Shets-Sheet 1- Aug. 20, 1946.

H. E. VAN VOORHEE-$ 2,406,272

ROLL SCREEN ASSEMBLY 6 Sheets-Shed, 2

Filed Dec. '5; 1942 I jar/6721. 27": firo/dzh infi v I I I 20, 1946- H. E. VAN VOORHEES 2,406,272

ROLL SCREEN ASSEMBLY I Filed Dec. 5, 1942 s Sheets-Sheet :5

g- 20, 1945; I H. E. VAN VOORHEES. 2,406,272

ROLL SCREEN ASSEMBLY Filed Dec. 5, 1942 6 Sheets-Sheet u- I l"""*-"-"j N T N x I "III; 1;

v I N firqld'fi. Kin %5r/ees 20, 1946 H. VAN VOORHEES ROLL SCREEN ASSEMBLY Fi l ed Dec. 5, 1942 6 Sheets-Sheet 5 fiivenior Jyaroif cznVqor Patented Aug. 20, 1946 2,406,272 ROLL SCREEN ASSEMBLY Harold E. Van Voorhees, Chicago, 111., assignor to poration of Illinois Borg-Warner Corporation, Chicago, 111., a cor- Application December 5, 1942, Serial No. 467,923

19 Claims.

This invention relates primarily to improvements in roller type screens or the like. The principal object of the invention is to provide an improved means for adjusting, latching and tensioning such devices.

In devices heretofore on the market, for adjusting, latching and tensioning screens, such as those which are longitudinally resilient, having ribbon like transverse elements and longitudinally extending resilient connectin means requiring a predetermined stretch or tensionin for proper optical effect and desired result, such for example, as those disclosed in United States Patents No. 2,078,940 of May 4, 1937, issued to J. J. Grebe and No. 2,194,222 of Mar. 19, 1940, issued to W. B. Ewing, there have developed serious objections to the adjusting, latching and tensioning means which have shown up in practical applications of the screen.

In the first place, it has generally been a practice to provide a tensioning means which at all times exerted considerable strain on the screen cloth, generally a strain suflicient to rapidly roll up the screen cloth when the latching means was released. The average user would release the latch, and turn the device loose letting it roll itself up. This would result in a sudden checking action when the lower rail of the screen reached the top, tending to distort the screen cloth and pull it loose from the lower rail. As a result, the average life of a screen was comparatively short.

Screen cloth having the construction disclosed in the above mentioned Grebe and Ewing patents is inherently stretchable lengthwise, that is, it will elongate from end to end and if tension is placed thereon, such stretching within the clastic limits of the material exists only while tension is placed on the screen. In order to secure the proper optical and solar effect it is desirable, in fact almost necessary, that the screen be tensioned-that is, that the screen cloth itself be stretched-while the screen is in normal position over a fenestra.

The elastic limit of such screen cloth is ordinarily critical and improper tensioning or stretching which is not uniform or which is to a greater than desired amount causes damage to the screen by altering the angulari-ty of the ribbon-like weft members and the size or shape of the loops of the warp strands, thereby destroying the uniformity and alignment of the spacing of the weft members.

Further, with the constructions heretofore on the market, the person lowering the screen to its extended length would normally grasp one side of the bottom rail of the screen and hook it first, thus distorting the screen cloth on that side. As a result, the screen cloth became torn and permanently distorted, which would tend to destroy the proper fit in the guide channels and spoil the desired and proper optical effect of the screen cloth by reason of the distortion. Also such distortion would let in insects and spoil the light-reflecting and absorbing qualities of the screen cloth.

A further objection was the fact that in previous constructions it was dimcult to make the screens properly fit the guide channels and still be able to stop the screen at any position and have it remain at that position. As a result usually excessive friction was required in the guide channels, or it was preferable to have such screens either extended full length or entirely rolled up. Most persons after using such a screen a short while would extend it to its full length and leave it there. This restricted the utility of the screen and consequently its desirability and J salability.

It is an object of this invention to overcome all of the above mentioned defects.

It is a further object of this invention to provide a construction in which a single handle positioned for even pull on the screen cloth is provided for raising and lowering the screen, and which handle is operable to tension the screen by elongating the warp'strands and likewise to release the catches.

It is an object to provide a catch means which automatically engages a catch receiving means when the screen is extended to its normal length, and thereby latches the screen in extended position and indicates to the operator the position at whichthe tensioning means shall be manually operated. In this connection, the catch means provided is novel, and it application and arrangement are novel.

One object of this invention is to provide a cam tensioning means which is lever operated. In this connection it is an object to provide a tensionin means which will uniformly distribute the tension.

Further, it is an object to provide a device in which substantially all of the tension is absorbed directly by an arbor or roller diametrically across its axle, and in which the arbor spring means is sufiicient only to counterbalance the weight of the screen. This accomplishes the object of eliminatingthe necessity for expensive, strong springs with, consequent saving in material and costs and with some reduction in the size of the arbor necessary to house such a spring.

It is another object of the invention to provide a device which will be rugged and have a comparatively long life, and a device which will allow movement of the screen by overcoming merely inertia and friction.

7 Likewise it is an object to provide a device which is readily manufactured by available machinery, and is comparatively inexpensive.

' These and other objects and features of this invention will become apparent from the following specification when taken together with the accompanying drawings in which:

Fig. l is a front elevational view disclosing an installation of a roll-screen to which the improvements herein disclosed are applicable, the control handle being indicated by dotted lines;

Fig. 2 is a fragmentary elevational view showing the details of the roller construction, the View being taken on the lines 2-2 of Fig. 3, looking in the direction of the arrows and a portion of the device being shown in cross-section;

Fig. 3 is a fragmentary side elevational view partly in cross-section, and take on the lines 33 of Figs. 1 and 2, looking in the direction of the arrows;

Fig. 4 is a view similar to that of .Fig. 3, but taken on the lines 4-4 of Fig. 2, looking in the direction of the arrows;

Fig. 5 is a fragmentary side. elevational view, showing the arbor and screen arrangement of Fig. 4, but with the position of the screen on the arbor bein changed by rollin a portion of the screen onto the arbor;

Fig. 6 is a fragmentary plan view in cross-sec tion, taken on the lines 6-6 of Figs. 1 and '7,

looking in the direction of the arrows;

Fig. 7 is a fragmentary, front elevational View in cross-section, showing the tensioning and latching means, taken on the lines 1-! of Fig. 6, looking in the direction of the arrows;

Fig. 8 is a fragmentary,.front elevational view taken on the lines 8-8 of Fig. 10, looking in the direction of the arrows, and showing the details of the latch, and cam tensioning mechanism, of the lower rail assembly, the latch appearing in engaged position;

Fig. 9 is a fragmentary elevational view gen-. erally similar to that of Fig. 8, the latch and cam assembly being shown in dotted lines, and the latch being in disengaged or released position as compared to the position of the latch of Fig.8.

Fig. 10 is a side elevational view taken on the lines tilof Fig. 8 looking in' the direction of the arrows, the View being enlarged in part to show details of construction on the screen cloth;

Fig. 11 is a fragmentary, elevational view taken on the lines I ll I of Fig. 8 looking in the direction of the arrows; and

Fig. 12 is a fragmentary, front elevational view, showing in detail the arrangement of the lower rail assembly.

Referring more in detail to the construction shown in the various drawings, and referrin first to Fig. 1, there is provided what may be termed a roll screen assembly installation 28. prises an arbor housing assembly 22', containing an arbor or roller assembly, hereinafter described in detail; a screen cloth 2d; a lower rail assembly 26;

guide rails

28 and 36. The construction is shown as installed in a conventional window opening 32 of a wall 34. 1

Referring next to. the construction of Figs. 2, 3, 4 and 5, and first to Fig- 2, there is provided This comthe arbor housing assembly 22, having the arbor 35 around which the screen cloth 24 is adapted to roll in raisin the roll screen assembly. This arbor 36 has the axle 38 on which it is mounted for rotation. provided with the bearin 49 which is attached to the arbor 35 and mounted for rotation on the axle extension 42.

At the other end of the axle 38, there is provided a second axle extension 44, diametrically enlarged at 45, and having a pawl engaging ratchet means 53, adapted to engage a pawl 5% (see Fig. 3 in particular). On its outer end, the axle extension M is preferably flattened on at least two sides or otherwise shaped so that it may be easily gripped by a wrench or the like for the purpose of rotating the axle 38 with respect to the arbor 36, for the purposes later apparent. This flattened end portion 52 is a part of the axle 38, the axle extension 44,.of which the flattened end portion 52 is a part, being attached to the axle 38 by means of a pin or the like 55.

The axle extension 42 is attached to the axle 33 by the pin 56.

The arbor 35 on the pawl end of said axle 38, is provided with the enlarged bearing 58, to which it is integrally attached. This enlarged bearing 58 seats on the axle enlargement #56, and preferably rests against the end Wall. of the arbor housing 62 (see Fig. 2) and the bearingv 4B preferably abuts against the end wall 55. of the arbor housing 62, the bearings at each end clearing the end walls 65) and as only sufiiciently to allow easy movement: of :the. arbor in rotating, Whilepreventing the arbor from moving longitudinally any material amount.

The, arbor 36, is preferably longitudinally channeled as shown at 66, in Fig. 4, and. is provided with hook engaging means 68, as shown in Figs. 4 and 5. This hook engaging means 68.1isadapted. to engage a hook-shaped member m forming the upper molding or edge of the roll screen 24, and in. the position of Fig. 4 the tensioning pull on'the screen is diametrically across the arbor, and does not affect the sprin 12, hereinafter described, materially. Other convenient attach' ing meansmight be used but the one disclosed seems preferable. that the, roll screen may be readily attached to or detached from. the arbor as desired.

I The axle, 38 has mounted thereon a coil spring 72. One end of the spring 72 is attached to the axle, preferably to the enlarged axle extension 45, asshown at M in Fig.2, and the. other end of the spring 12 is attached to the. arbor, preferably to the end of the arbor 35 as shown at 75. It is readily understood that the. movement of the arbor 36 with respect to the axle 38 is generally dependent upon the tensioning of the spring 12. It is one of the important features of this invention that the spring 72 should be of such strength and so adjusted as to regulate the arbor to where the load of the screen cloth 2d, molding 19, and lower rail assembly 2%, together with any other weight on the screen, is almost exactly counterbalanced. This is to permit the positioning of the screen at any position desired from full extension to completely rolled positionand (when it is so positioned) to retain the screenin that position in the absence of external force exerted thereon. It is, also for the purpose, of facilitating. the raising and lowering of even a heavy screen by making such operation a; mere matter of overcoming. inertia and. friction,. and. therefore. a. very easy matter. inxthe ordinary installa- In this connection, the arbor 36 is In this connection, it is noted tion. Thus the spring acts as a counterbalance for the screen cloth and mechanism, and extraneous forces are used to mOVe the screen.

The proper construction to secure the necessary counterbalancing is not difiicult to determine.

The weight of the lower rail assembly 26 and the extended screen cloth 24 is determined when the screen cloth is in the extended or unrolled position. When in this position, the radius of the arbor 3B is determined, and the combined weight of the extended screen cloth and lower rail assembly is multiplied by the radius of the arbor 35, which gives the torque in inch-pounds when the screen cloth is unrolled.

Next, the weight of the lower rail assembly and any extended portion of the screen cloth is determined when the screen cloth is wound onto the arbor 36, and the radius of the arbor 36 with the screen cloth Wound thereon is determined. These two sums are then multiplied together and the product is the torque when the device is in the rolled position.

The next step is to determine the number of revolutions necessary to change the screen cloth from the unrolled position (of the first step) to the rolled positon of the second step. By determining the difference in torque between the two positions and by dividing the torque difference, that is, the increase in torque, by the number of revolutions from the rolled to the unrolled position, the amount of torque per revolution is determined. A spring with the proper characteristics may then be selected by calculation or by using an engineers handbook or charts furnished by the spring manufacturers. It is not diiiicult to check the accuracy of the above calculations by using the formula:

Ed 11.25DN

where Ma=moment per turn in inch lbs. E=Youngs modulus for steel 30,000,000 Z=wire size in inches D=mean diameter of spring N=number of coils .the deflection of the spring is increased by the necessary amount to counterbalance the load.

It is understood that the axle 38 is normally held against rotation by the pawl 56 engaging the teeth-oi the ratchet 43, except for the purpose of winding the spring, in which case the turning of the member 52 to the right lifts the pawl over the teeth of the ratchet 48. The pawl is preferably spring-pressed by meansof the spring I8, so that it will not be accidentally disengaged allowing the spring to unroll. However, the pawl 5i) may be released from the ratchet 48 by lifting the pawl knob 8!! provided for that purpose.

The arrangement of the guide rails 28 and 30 will be most clearly apparent from an examination of Figs. 3, 6 and 7. These guide rails 28 and 30 preferably comprise a light gauge angle iron 82 which is fastened to the window molding by any convenient means (not shown). Attached to each angle iron 82 by bolts 84 or the like, is the'channel member 86. The channel member 86 is channelled to receive one edge extension I20 .7) in a position to be engaged by a cam 96 and latch 94 for latching and tensioning the screen.

Preferably the stops 98 are provided on either side as a part of the projecting strip 83, and near the top thereof, for the purpose of engaging the lower rail and preventing it from jamming against the arbor housing 62, and possibly injuring thev hands of the operator or damaging the screen mechanism. I

As will be apparent from examination of the enlarged portion of Fig. 10 (and from consulting the above mentioned Ewing and Grebe patents), the type of screen to which this is primarily directed should be tensioned longitudinally to give the prope optical characteristics. It should not normally have greater stress placed on one side of the screen than on the other, but should be uniformly tensioned across the whole. The tensioning of the type of screen disclosed in the Grebe and Ewing patents above mentioned includes elongating the screen cloth by a stretching action within the elastic limits of the warp strands of the woven screen. Thus the proper optical and solar characteristics necessitate this stretchingaction when the screen is over the window opening. Such tension other I than merely retaining the screen taut would be of no particular value in the ordinary type of screen cloth not using a ribbon-like weft member. Should the tensioning be excessive in the screen cloth using the ribbon-like weft member, the weft member may be pulled out of proper angular position. This tensioning is se cured in an improved manner as hereinafter more fully disclosed.

Referring to the construction shown in Figs. 6 to 12 inclusive, in which the lower rail assembly 26 is illustrated in detail, this lower rail assembly 26 comprises a housing or case .IGQ, which preferably consists of two sheets together forming the sides and bottom of the housing I00, the metal being shaped as is clearly apparent from Fig. 10 in particular, and extending longitudinally, substantially the width of the space between the rails 23 and 30. side plates are turned under and meet at IBI as indicated in Fig. 10, thus forming the bottom of the housing we when the device is assembled.

Mounted on one side of the housing on case I05 and usually on the side which would be nearest the operator such as the room side of a window, is the handle I02. (See Figs. 1 and 6.) It is desirable that this handle Hi2 be spaced about an equal distance from the ends of the housing we, and journalled for rotation in the side wall 198 and in a reinforcing bracket I04. This handle I62 extends into the housing I00, and has mounted for rotation therewith on its inner end, a lever or rocker arm I06. This lever Preferably these arm I08 may be keyed to said handle or may be otherwise attached thereto in order that the two become integral and rotate together. The lever arm N36 is preferably retained in place by means of the nut IE8, which likewise holds the handle I92 in position.

At its outer end, the lever arm I86 has journalled thereto by means of the pins i3 2, the

links or levers [Hi and H2. These levers are journalled to the lever arm I89 for rotation with respect to said lever arm, whereby the rotation of the handle I02 with consequent turning of ,the lever arm I66 moves thelevers i 16 and 1 l2 longitudinally in the case I09.

Journalled to the outer end of the levers H and H2 are the tensioning cams 95. Referring particularly to Figs. 6, 7 and 10, it will be noted that the cam 96 is located ina box H6, which box H6 is, in turn, located in one end of the housing Hill. A similar box H6 is also located in the other end of the housing I08. The cam 9-8 is mounted for rotation about an axis formed 'by a bolt or the like H8 carried by the bracket vided in said end wall for that purpose (see Fig.

-11 in particular, and also Figs. 6, 7 and 8). This slot or opening permits the cam to move inward- I ly and outwardly with respect to the-end 524 of said box lit, and to engage the side rail pro" jecting strip 88 for the purpose hereinafter noted.

The catch 94 is also mounted in said box H6, and'it is journalled on the axle means I22, and rotates thereon within the limits permitted by he box. The toe or hook portion of said catch 9 normally extends out past the outer end I26 of the box, through a catch slot or opening 98,

so as to engage under pressure of the spring E25, the projecting strip 88, as hereinafter described.

The cam 95 and the catch 94 are normally 7 1 urged into the engaged or latching position by means of a spring member I25, one end of which engages the catch 54 and the other end of which engages the cam 56, the spring being wound on or carried by the axle bolt H8, and doubled upon itself so that its doubled section extends to l a position of engagement with and is held by the inner end wall will be clearly apparent from examination of l Figs. 6, 7 and 10.

The screen cloth 2 preferably is pro'videdwith reinforcing channel members !28 at its lower edge portion (see Fig. which channel mem- 3 bers I28 maybe attached to the screen cloth by 3 means of the brads 535 or any convenient means. The screen cloth may be attached to the end rail by means of the clamping action exerted I by the upper portion of the housing we (see Fig.

10) when the sides of said housing are held firmly clamped in place as by means of the bolt 32 or the like.

There are several obvious methods of assem- Qbling the unit for operation, and to describe such methods in detail would serve no useful purpose here and would unnecessarily lengthen I25 of the box 586, thus holdl ing the spring I26 tensioned.- This construction this disclosure.

After assembly, assuming for the purpose of :description that the screen is in the rolled-up position, the screen assembly may be lowered by; grasping the handle I62 and pulling downward as far as desired. The assembly will remain counterbalanced in such an operation, until it reaches the position where the screen cloth is fully extended as in Fig. 4 but not with tension thereon. In this movement downward, the catch 94 rides against the third rail projecting strip 88. This would normally be the position shown in dotted lines in Fig. 9.

When the screen has reached its downward limit of movement before tensioning, the catch 94 will click into the position below the strip 88 indicated in Fig. 3. In all of the movement so far described the handle )2 is pointing upward.

The catches 94 normally click into position on both ends at the same time because the screen is pulled down in the center and will come down straight. As soon as these catches 94 click into place, the handle tion shown in Fig. 6, and the cam 96 will engage the lower edge of the projecting strip 88, and will exert a downward force moving the screen to the exactly tensioned position desired, as shown in Fig. 7. This will not over stretch the screen, or twist or warp it. Where reliance is not placed on the catches to indicate the position for beginning .the camming action, the cams might be forced outwardly against the projecting strip 88, and due .to the considerable leverage secured, the projecting strip 88 or some other part would have to give. This might damage the screen installation, so that it is desirable-to have the catches engaged-by clicking into position.

It is here noted that the very important object of tensioning the screen without exerting any tensioning pull on the sprin i2 is accomplished in this method. When the tensioning action takes place, the arbor is in the position shown in Fig. 4, and the tensioning'pull is diametrically across said arbor as indicated by the arrow in said figure. This does not exert any additional pull on the spring, and the spring is merely exerted a sufficient amount to counterbalance the normal untensioned' Weight of the screen and lower rail assembly. This is an extremely important feature as was pointed'out in connection with the objects.

- When it is desired to' release the cam and catches so that the screen assembly may be moved up into the rolled position, the handle I02 is turned so that it is in the position shown in Fig.

1 in dotted lines, and is then turned a slight bit further to the operators right (in a clockwise direction with respect to the operator) so that the cam and lever joining pin l36, which .pro-

jects suihciently to contact the catch 94 at the a top as is indicated in Fig. 10, will press against catch 94 as in Fig. 12 and will disengage said catch from the projecting Strip 88, freeing the screen and allowing it to be moved upwardly.

It is understood that the handle mechanism above described does not necessarily have to work in the exact manner disclosed. The parts could be reversed so that the handle would rotate in the opposite direction, that is, anticlockwise, but the principle would be the same, and for the purposes of disclosure there would be no difierence. 1 I

I02 may be turned to the posi' As soon as the catch 94 has cleared the bottom of the strip 88, the handle may be moved into an upright position for further positioning of the screen, in which position the cams and catches assume the positions indicated by dotted lines in Fig. 9.

While I have described my invention in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration rather than limitation and that the invention is to be defined by the appended claims which should be given a scope as broad as commensurate with the prior art.

I claim:

1. A roller type screen assembly comprising an open mesh woven screen cloth having warp and weft stands; a roller automatically rotatable in a winding direction and to which one end of said screen cloth is detachably secured; means for arresting unwinding movement of said screen cloth when a predetermined length thereof is withdrawn from said roller; a rail secured to the other end of said screen cloth; and control means carried by said rail, said control means including means operable to latch said rail in position when said predetermined length of screen has been unwound from said roller to thereby retain said unwound length of screen cloth in extended position, said control means also including means operable to effect a lengthwise tensioning of the screen cloth between said rail and arresting means by moving the rail beyond said latched position, whereby to stretch the warp strands of the screen cloth.

2. A roller type screen assembly as defined in claim 1, wherein the means for efiecting lengthwise tensioning of the screen cloth comprises cam means on said rail.

3. A roller type screen assembly comprising an open mesh woven screen cloth having warp and .weft strands; a roller automatically rotatable in a winding direction and to which one end of said screen cloth is detachably secured; means for arresting unwinding movement of said screen cloth when a predetermined length thereof is withdrawn from said roller; a rail secured to the other end of said screen cloth; guide means for receiving the margins of said screen cloth and the ends of said rail; and control means carried by said rail, said control means operable to latch said rail to said guide means when said predetermined length of screen has been unwound from said roller to retain said unwound length of screen cloth in extended position, said control means also including cam means on said rail operable to engage said guide means for effecting a tensioning of the unwound length of screen cloth by moving the rail beyond said latch position, whereby to stretch the warp strands of the screen cloth.

4. A roller type screen assembly as defined in claim 3, wherein the cam means on said rail are adapted to'be operated by a single manually operable control means comprising a handle.

5. In a roller type screen assembly for installation in a fenestral opening having a spring loaded adjustable roller automatically rotatable in a screen winding direction, an open mesh woven screen cloth detachably secured at one end to said roller, said screen cloth having ribbon-like weft strands and warp strands adapted to be elastically elongated; a rail secured to the other end of said screen cloth; means for arresting unwinding movement of said screen cloth when a predetermined length thereof i withdrawn from said roller; and guide means for receiving the margins of said screen cloth and the ends of said rail, those improvements comprising: automatically projected latching means carried by said rail and adapted to engage said guide means at a predetermined extended position of said screen cloth for releasably retaining said rail and screen cloth at said position; separate cam means carried by said rail operable to engage said guide means after the latching of the screen and rail has been effected and adapted to tension said screen cloth between said rail and arresting means by moving the said rail beyond said latched position to effect said elastic elongation of the warp strands to hold the screen cloth .taut; and mean comprising a handle operatively connected to said cam means for engaging and disengaging said cam means from said guide means, said handle actuated cam means being operable to also disengage said latch mean upon a continuation of the movement releasing said cam means, whereby said screen cloth may be rewound upon said roller.

6. In combination with screen cloth wound upon an automatic winding roller and having ribbon-like weft strands and having warp strands which are inherently elastic to permit longitudinal elongation for tensioning an unwound length of the cloth, means maintaining one end region of said screen cloth against longitudinal movement in an unwinding direction when a predetermined length is withdrawn, and means at the other end of said screen cloth operable to stretch the withdrawn length of screen cloth thereby tensioning the latter.

7. In combination with screen cloth wound upon an automatic winding roller and having ribhon-like weft strands and having warp strands which are inherently elastic to permit longitudinal elongation for tensioning the cloth, means maintaining one end of said screen cloth against longitudinal movement when in unrolled position, and means at the other end of said screen cloth operable to stretch the unrolled screen cloth thereby tensioning the latter, said last mean including an end rail attached to said other end of said screen cloth and means intermediate the ends of said end rail for operating said tensioning means.

8. In combination With a wound length of screen cloth adapted to be extended by longitudinal elongation while tensioning the cloth, means maintaining one end of said screen cloth against longitudinal movement when in unwound position, and means at the other end of said unwound length of screen cloth operable to stretch the screen cloth for effecting a tensioning thereof, said last mentioned means including an end rail with cam elements located adjacent the respective ends thereof and a central manually operable control means for operating said cam elements.

9. In combination with screen cloth adapted to be extended by longitudinal elongation while tensioning the cloth, means maintaining one end of said screen cloth against longitudinal movement, and means at the other end of said screen cloth operable to hold and stretch the screen cloth thereby tensioning the latter, said means including an end rail carried by said screen cloth, latching means thereon holding said screen cloth in unstretched condition and separate cam devices on said rail for effecting the, aforesaid stretching and tensioning, of said screen cloth.

10. In a screen assembly of the class described,

a roller; means on said roller for receiving and 2&061272 l1 releasably retaining a longitudinally extensible tensionable screen adapted to be rolled thereon, said means comprising coacting hook portions on the periphery of said roller and the adjacent portion of said screen; catch means latching said screen in extended position; cam means operable to apply tension to the'latched screen; and means operable to release said cam means and then to release said catch means, permitting winding of a the screen on said roller, the arrangement being 1 such that said cam'means is operable to extend said screen for the tensioning operation, after saidscreen is latched, by exerting a force on said screen diametrically of the roller.

11. A screen as defined in claim 19, wherein the cam means and the latch means are actuated to release the screen'by a common means.

1 2. In a roller type screen assembly for a win.- doW, comprising a roller mounted in an end pcrtion of the window and having automatic rewinding action; a reticulate screen adapted to be wound on and unwound from said roller,

7 screen having warp strands characterized by elasticity to permit elongation thereci for tensioning the screen, said screen having an end edge free of said roller; means defining fixed cam and latch engaging elements at the regions of the window which are remote to said roller; and a rail attached to said free edge of the screen and adapted for movement in a direction toward said elements to withdraw at least a portion of said screen from s id roller; hose improvements whi h comprls yieldable latches at the ends of {said rail adapted when registered with said elements to be omatically projected thereinto to latch said rail and maintain the s reen against the rewinding action of aid roller; means for restraining the l unwindi g movement of said screen when said rail is latched; cam means ad acent the ends 01 said rail; and manually operable means intermediate the ends of said rail adapted to move said cam means for cam action with respect to said elements thereby to force said rail beyond said latched positicnand effect said elongation of said warp trands and the tensioning of the screen be.- I twe n said rail a d said r s n mesme- 1.3. A roller type screen as defined in claim 12, wherein the cam and latch means are separate and the manually operable means moving said cam means are adapted to release said latch means by continuing the movement of said cam means i a, releasing direction and engaging the latch means by t e m means and u si s ;lai ch means in a retracting direction.

lei. A roller type screen assembly as defined in cla m 12, w rein the me ns d finin sai c m an latch enga ing e ements comprise gu d s for the opposite l n tudinal mar ins of sa d s n, h vin cam and latch eng n recess s in the portions thereof which are remote to said roller.

15. In combination With a screen cloth having.

ribbon-like weft strands and havingwarp strands adapted for longitudinal elongation for tension- 7 ing the cloth, a roller for winding and unwinding said screen cloth; means at one end of said screen .cloth for arresting movement thereof 1ongitudinally of said warp strands when said screen cloth is in unwound position, and means defining latches and earns at the other end of said screen cloth, said latches being operative to effect the latching of the screen cloth when extended to its arrested untensioned position and saidcams being-then operative to effect said elongation of the warp strands to tension the cloth.

3 16. In a roller type screen assembly for a fenesperipheral tral' opening or'the like, comprisinga reticulated screen cloth having warp strands with elastic ha a te c a r ll r automatically rotatable in a winding direction, means securing one end region of said. screen cloth to said roller; uide means fo said screen cloth, means arresting unwinding movement of said screen cloth from said roller when .a predetermined length is withdrawn fromsaid roller, latch means at the free .end of the screen cloth, said latch means being adapted to latch the screen in its arrested and untensioned position and means carried at the free end of said screen cloth adapted to extend said screen cloth longitudinally of the weft strands for uniform tensionin of said screen cloth.

17. In a roller type screen assembly for a window, comprising a reticulate screen having warp strands characterized by elasticity to permit elongation thereof for tensioning the screen; a roller mounted in the top portion of the window and having automatic rewinding action, said screen being initially wound on said roiler and having a free end edge; and a rail attached to said freeeolge of the screen and adapted for movemerit-in a direction away from said roller to' withdraw at least a portion of said screen from said roller; those improvements which comprise, guides along the upright portions of said window, said guides having fixed recesses adjacent the sill of the window, said rail and screen being guided by said'guides; spring urged "latches pivoted at the rail ends adapted when registered with said recesses to be projected thereinto to latch said rail and to maintain the screen against said rewinding action of the roller; means effective on the screen when said rail is latched to restrain further unwinding movement of said screen-j cam means fulcrumed at the rail ends adjacent said latches; and common means carried by said rail for operating said cams, said common means in said recesscs'thereby to force said rail-down- Wardly beyond its latched position and said elongation of the warp strands tliereby to tat-510a said screen between said rail nossidsaeehrestraining means, and movementfof said rocker arm in a reverse direction being adaptedtoirelease and withdraw said cams, and a contindation of said reverse movement causing said fcams to engage said latch means and withdrvfthe latch means from said recesses.

18. A window screen assembly comprising: a roller; automatic means normally urging said roller in a winding direction, said roller having a opening extending longitudinally thereof, one longitudinal edgecf said opening having a hook element extending therealong; a piece of screen cloth of a given width and length to cover a given size window opening; a hook element secured to the upper end of said screen cloth and interengageable with the hook element on said roller for detachably securing said screen cloth to said roller and for exerting a pull in a direction diametrically of said roller when said screen cloth is fully unwound from said roller;

latch engaging means for latching saidscreen 7 cloth in extended, substantially untensioned position when said screen cloth is fully unwound movement of said'rocker arm from said roller and for stretching said screen cloth beyond said fully extended position to longitudinally tension the same.

19. A window screen assembly comprising: a

roller; automatic means normally urging said 5 at the lower part of said window opening; and 10 14' a means carried by the lower end of said screen cloth cooperable with said latch engaging means for latching said screen cloth in extended, substantially untensioned position when said screen cloth has been fully unwound from said roller and for stretching said screen cloth beyond said extended position to longitudinally tension the same.

HAROLD E. VAN VOORHEES.