US3036629A

US3036629A - Projection screen

Info

Publication number: US3036629A
Application number: US656426A
Authority: US
Inventors: Nicholas William
Original assignee: Radiant Manufacturing Corp
Current assignee: Radiant Manufacturing Corp
Priority date: 1957-05-01
Filing date: 1957-05-01
Publication date: 1962-05-29
Anticipated expiration: 1979-05-29

Description

May 29, 1962 w. NICHOLAS PROJECTION SCREEN 3 Sheets-Sheet 1 Filed May 1, 1957 IN VE NTOR. WWW/d6 Z aZ/m May 29, 1962 w. NICHOLAS PROJECTION SCREEN 3 Sheets-Sheet 2 Filed May 1, 1957 INVENTOR. Maw

May 29, 1962 w. NICHOLAS 3,036,629

PROJECTION SCREEN Filed May 1, 1957 3 Sheets-Sheet 3 9,-KMW W- United States Patent 3,036,629 PROJECTHON SCREEN William Nicholas, Evanston, Ill., assignor to Radiant Manufacturing Corporation, Chicago, 111., a corporation of Illinois Filed May 1, 1957, Ser. No. 656,426 8 Claims. (Cl. 160-2 3) This invention is directed to projection screens for use in exhibiting pictures projected thereon and this application is a continuation-impart of my copending application Serial No. 604,790, filed August 17, 1956.

The principal object of this invention is to provide an improved projection screen wherein improved means are provided for positively limiting unrolling of a flexible screen from its carrying roller so as to prevent tearing or separation of the screen from the roller, wherein the improved means for positively limiting unrolling of the screen co-operates, in one form of this invention, with a tensioning means for tensioning the flexible screen in picture exhibiting position to adapt it for use in exhibiting three-dimensional pictures, and wherein the improved means for positively limting the unrolling of the screen co-operates, in another form of this invention, with means for maintaining the screen in picture exhibiting position to adapt it for use as a wall mounted type of projection screen.

Further objects and advantages of this invention will become apparent to those skilled in the art upon reference to the accompanying specification, claims and drawings, in which:

FIG. 1 is a side elevational view of one form of the projection screen of this invention, with the legs of the supporting stand extended and with the screen case vertically arranged;

FIG. 2 is a perspective view of the projection screen with the screen case horizontally arranged and with the flexible screen extended to picture exhibiting position;

FIG. 3 is a view similar to FIG. 2, but illustrating another form of the invention wherein the flexible screen is tensioned so as to provide a flat surface for the projection of three-dimensional pictures;

FIG. 4 is an enlarged partial view of the handle member which may be utilized in the form of the invention illustrated in FIG. 3 and which may be of the type shown and described in my co-pending application Serial No. 418,946, filed March 26, 1954;

FIG. 5 is an enlarged sectional view of a portion of the projection screen illustrated at the left hand side of FIGS. 2 and 3;

FIG. 6 is a vertical sectional view taken substantially along the line 6-6 of FIG. 5;

FIG. 7 is an exploded perspective view of a portion of the mechanism illustrated in FIGS. 5 and 6;

FIG. 8 is an enlarged sectional view, similar to FIG. 5, of another form of this invention, which may be contained in the left hand portion of the projection screen illustrated in FIGS. 2 and 3 FIG. 9 is a vertical sectional view taken substantially along the line 99 of FIG. 8;

FIG. 10 is a perspective view of a portion of the mechanism illustrated in FIG. 9;

FIG. 11 is an elevational view of another form of this invention, particularly a projection screen of the wall mounted type;

FIG. 12 is a horizontal sectional view through the projection screen illustrated in FIG. 11 and taken substantially along the line 12-12 of FIG. 11;

FIG. 13 is an enlarged vertical sectional view taken substantially along the line 13-13 of FIG. 12 and illustrating the projection screen unrolled to the last turn;

aesaszs Patented May 29, 1962 FIG. 14 is a view similar to FIG. 13, but illustrating the projection screen rolled for several turns upon the roller;

FIG. 15 is an exploded perspective view of a portion of the mechanism illustrated at the left of FIG. 12.

Referring first to FIGS. 1 and 2, one form of the projection screen of this invention is generally designated at 10. It comprises a portable collapsible stand having an upright tube or post 11, which is preferably non-circular in cross-section. A bracket 12 is slidably carried on the upright tube 11 and a plurality of legs 13 are pivotally secured to the bracket 12. Fixed to the bottom of the upright tube 11 is a bracket 14 and links 15 are pivotally secured to the bracket 14 and to the legs 13. The legs 13 may be folded together for transportation purposes and when this is done the bracket 12 slides upwardly on the tube or post 11. Suitable latch means (not shown) may be provided for holding the legs 13 in collapsed position. When the legs are extended for exhibiting purposes, as illustrated in FIGS. 1 and 2, the bracket 12 slides downwardly on the upright post 11. In this way the supporting stand is maintained in an upright position.

An extension rod 16 is slidably mounted in the upright tube or post 11, the extension rod being guided for vertical movement by a collar (not shown) carried on the lower end of the extension rod and by a cap 17 carried on the upper end of the post 11. The extension rod 16 is maintained in any desired extended position by a nipping lever 13 extending through a suitable opening in the upright tube 11 and gripping the extension rod 16. The nipping lever is resiliently urged into gripping position by means of a spring 19 and the action of the spring may be overcome by manually manipulating the nipping lever 18 to allow desired adjustment of the position of the extension rod 16. The upper end of the extension rod 16 carries a bracket 21 having a hook portion 21 and a projection 22. There is thus provided a hook member which is slidably and adjustably carried by the post. A handle member 24 having a handle portion 25 is slidably carried on the upright tube or post 11. Downward movement of the handle member 24 is limited by a pin 26 carried by the post 11. A resilient nipping lever 27 is carried by the handle member 24 and operates to grip the post 11 for maintaining the handle member in any desired position above the pin 26. By manipulating this nipping lever 27 the handle member 24 may be adjustably positioned along the post 11. A bracket 28 is pivotally mounted to the handle member 24 as indicated at 29 and this bracket member carries a screen case 30 which is internally provided with a spring actuated roller. One end of a flexible projection screen 31 is secured to the roller within the screen case '30 and the other end is provided with a suspension slat 32. The flexible screen 31 may be provided with any suitable picture projecting sur r face such as a beaded surface where motion pictures are to be exhibited, or an aluminum type surface where color pictures are to be exhibited. A bracket 33 is secured to the suspension slat 32, and it is provided with a bail 34- for the purpose of withdrawing the screen 31 from the screen case 3% and for hooking over the hook member 20 to hold the flexible screen in picture exhibiting position as illustrated in FIG. 2. The ends of the screen case 30 are closed with end caps 35, at least one of which is provided with a depression 36 for receiving the projection 22 on the hook member for locking the screen case in parallel relation to the post 11, as illustrated in FIG. 1.

The type of projection screen thus far described is suitable for normal exhibiting of pictures projected thereon. However, where an extremely flat surface is required, as for the projection of three-dimensional pictures, a somewhat diflerent arrangement may be utilized, such arrangement being generally designated at 46 in H6. 3. Here a resilient means in the form of an elongated spring member 41 is secured at its ends to the suspension slat 32 as indicated at 42. This spring member 41 is provided with a bracket 43 which carries a bale 44 which is adapted to be hooked over the hook member 26. This resilient means, including the spring member 41, is utilized for the purpose of tensioning the flexible screen 31 to provide an extremely flat surface. This resilient means is capable of applying a greater tensioning force to the screen 31 than can be applied by the spring actuated roller. In order to prevent the screen case from moving upwardly, under the tensioning afforded by the spring member 4-1, a handle member 45 may be utilized, and this handle member 45 may be of the type shown and described in my co-pending application Serial No. 418,946, filed March 26, 1954. This handle member 45 is illustrated in more detail in FIG. 4. Here the handle member 45 is slidably mounted on the upright post or tube 11 and is provided with a handle portion 46. Located within the handle member 45 is a double acting nipping lever 47, the end 48 of which extends out from the handle member 45 for manipulation purposes. The nipping lever 48 pivots about a shoulder 51 in the handle membet and is provided at its inner end with a post 49 surrounded by a spring 56. The shoulder 51, post 49 and spring 50 operate in conjunction with the nipping lever 47 to prevent movement of the handle member 45 in either direction on the post 1 1, but when the nipping lever 47 is manipulated through its extension 48, the handle member 45 may be adjusted to any position along the post 11. Since the handle member 45 is locked against movement in the upward direction, it is therefore possible to apply tension to the flexible screen 31 atforded by the resilient means including the spring member 41.

Referring more particularly to FIGS. to 7, a mechanism is provided for positively limiting the unroliing of the flexible screen 31 from its carrying roller, this mechanism affording two main functions, one function is to absolutely prevent tearing or separation of the screen from the roller and the other function is to co-operate with the tensioning means illustrated in FIG. 3 to provide for the tensioning of the flexible screen in picture exhibiting position, which is particularly useful in the exhibiting of three-dimensional pictures. In the arrangement of FIGS. 5 to 7, there is provided a post 55 having a flange 56 and a squared extension 57 which is secured against rotation to the end cap of the screen case 30. A spacer member 58 having a squared hole, also receives the squared extension 57 of the post 55 and is secured to the end cap 35, as by Welding or the like, to aid in supporting the post 55. The post 55 is rigidly secured to the spacer 58 and the end cap 35 by peening over the end of the squared extension 57 where it extends through a. squared hole in the end cap 35, the peening being illustrated at 59.

Rotatably mounted on the post 55 is a bracket 61 which is secured by rivets 63 or the like to one end of a roller 62. In this way this end of the roller 62 is mounted for rotation on the post 55. The other end of the roller 62 may be mounted for rotation and may be provided with spring means for rotating the roller 62 in a rolling direction in the manner illustrated and described in my aforementioned co-pending application Serial No. 418,- 946, filed March 26, 1954. Preferably, the roller 62 is formed from an extruded tube having a shoulder 63 of a height substantially equal to the thickness of the flexible screen which is rolled on the roller. The end of the flexible screen 31 is butted against the shoulder 63 and is suitably secured in place on the roller 62 by a suitable adhesive or the like. Due to this shoulder 63 and the butting of the flexible screen thereagainst, a smooth surface is at all times presented to subsequent layers of the flexible screen as it is rolled on the roller and, accordingceases 4 ly, any tendency to develop wrinkles or indentations in the screen is eliminated.

The roller 62 adjacent one-edge of the screen 31 and adjacent the shoulder 63 in the roller, is provided with an opening 64, one edge 65 of the opening acting as a stop edge and another edge 66 thereof operating as a camming edge. This opening 64 in the roller is normally covered by the screen 31 rolled upon the roller and it is exposed only when the screen 31 is unrolled to uncover the opening, i.e. to its last turn from the roller, as illustrated in FIG. 6. A mounting bracket 68 is secured to the inside of the screen case 30, as by welding or the like, in alignment with the opening 64- in the roller 62. This bracket 68 is provided with a pair of cars 69 for pivotally mounting a stop member 70 having arms 71. A pin '72 extends through the cars 69 on the mounting bracket 63 and the arms 71 on the stop member 70 for pivotal mounting purposes. A spring 73 arranged about the pin 72 and contacting at its ends the stop member 76 and the bracket 68, operates to resiliently urge the outer end of the stop member 70 toward the roller 62. The stop member "7% is provided at its outer end with a stop shoulder 74, which is adapted to engage the stop edge 65 of the opening 64 in the roller 62, and it is also provided with cam means which is adapted to be engaged by the camrning edge 66 of the opening 64 in the roller 62.

When the screen 31 is rolled upon the roller 62, the stop member 70 rides upon the screen rolled upon the roller, and, since the screen 31 covers the opening 64 in the roller 62, the stop member 70 is prevented from entering the opening 64. Thus, the roller 62 may be freely rotated without interference from the stop member 70 when the screen 31 is rolled upon the roller. This allows the flexible screen 31 to be freely unrolled from the roller 62 and withdrawn from the screen case 30. When, however, the screen 31 is unrolled from the roller 62, to the last turn, as illustrated in FIG. 6, the opening 64 in the roller 62 is uncovered and the free end of the stop member 76 is advanced by the spring 73 into the opening 64. When this occurs, the stop shoulder 74 on the stop member 76 engages the stop edge 65 of the opening 64 in the roller 62 and stops further rotation of the roller 62 in an unrolling direction. This, therefore, prevents complete unrolling of the screen from the roller and otherwise prevents tearing and separation of the screen from the roller. This positive stopping of the roller at this position also makes it possible to tension the flexible screen 31. Thus, when the flexible screen 31 is withdrawn to picture exhibiting position wherein the screen is unrolled from the roller to the last turn to uncover the opening, and the bale 44 is secured to the hook member 24}, the hook member 24} and the handle member 45 may be adjustably moved apart with respect to each other, and due to the action of the spring member 41, as illustrated in FIG. 3, a large amount of tension is applied to the flexible screen 31 to maintain it in a flat condition which is admirably suited for the projection of three-dimensional pictures.

When it is desired to roll the screen upon the roller in the screen case, the extended screen is detached from the hook member 26 and the spring actuated roller 62 operates automatically to roll the screen thereon. As the roller 62 is thus rotated in the rolling direction for this purpose, the cam means 75 on the stop member 70 is engaged by the camming surface 66 of the opening 64 to raise the stop member 70 from the opening 64, so that free rolling of the screen on the roller is assured.

Referring now to FIGS. 8 to 10, another form of mechanism is illustrated for accomplishing the same results as are accomplished by the mechanism of FIGS. 5 to 7. Here, like reference characters have generally been utilized for like parts. The flexible screen 31 is secured to the roller 62 against the shoulder 63 in the manner described above. A stop member 86 is provided with a mounting ear 81 which carries a pin 82 which, in turn, pivotally mounts the stop member 81) in a bearing member 83 secured to the end cap 35 of the screen case 30, the pin 82 and the stop member 81 being held in place by peening over the end of the pin 82. A spring 154- engaging the stop member 811 and the spacer 58, normally urges the stop member 80 toward the roller 62. The stop member 30 is provided with an car 85 which is in alignment with the opening 64 in the roller 62, and this car 85 is provided with a stop shoulder 86 for engaging the stop edging d of the opening 64 and a cam means 87 for engaging the camming edge 66 of the opening 64. The stop shoulder 85 and the cam means d7 of the stop member 81), operate in the same manner as described above in connection with the mechanism illustrated in FIGS. 5 to 7 and, therefore, a further description is not considered necessary. The car 85 also preferably carries a wheel means 88 which rolls upon the screen 31 where it is rolled upon the roller 62, this wheel means 83 operating to prevent wear upon the screen during rolling and unrolling of the screen on the roller.

Another form of projection screen of this invention is generally designated at 98 in FIG. 11, this form of projection screen being of the wall mounted type wherein the flexible screen 31 is withdrawn downwardly from the screen case 92 by pulling on the slat 32. The screen case 92 may be suitably mounted on a wall or the like by a supporting member 91 and the screen case may be provided with suitable end caps 93. This form of the invention, in addition to providing a mechanism for preventing tearing or separation of the flexible screen from the roller, also includes provision for holding the screen in withdrawn position. The details of the mechanism of the projection screen 98! are illustrated in FIGS. 12 to 15.

Secured in the screen case 92; adjacent each end thereof are brackets 94 which are utilized for supporting the roller 95 within the screen case. At one end the roller 95 is provided with a bracket 96 which carries a pin 97 which is rotatably mounted in the adjacent bracket 94, this one end of the roller 95 thereby being supported for rotation within the screen case 92. Arranged at the other end of the screen case is a shaft d9 having a non-circular end 1190 which is received in a non-circular opening in the other bracket $4. In this way the shaft 519 is secured against rotation with respect to the screen case 92. The shaft 99 adjacent the bracket 1 4 is provided with a collar 1&1 which, in turn, is provided with a latch shoulder 1110.. A bracket 1% having longitudinally extending ears 165' is secured by rivets 1% to the end of the roller 95. The bracket 1134 is provided with a round hole for receiving the shaft 99 so that this end of the roller 95 is rotatably mounted on the shaft $9 and supported thereby. The bracket 111 is provided with a pair of ears M17 struck therefrom and one end of a coil spring 108 is secured to these ears. The other end of the coil spring 1% is secured to a bracket 1139 which, in turn, is secured to the shaft 99. The inner end of the shaft 99 is -rotatably mounted in a bracket 119 secured within the roller 95 so as to provide an inboard support for the inner end of the shaft 99. The spring 183 connected between the stationary shaft 9% and the bracket 194 secured to the roller 95 operates to rotate the roller 95 in a rolling direction.

A pawl 115 is pivotally mounted on the bracket 1114 by means of a pivot pin 116. This pawl has a shoulder 117 which is adapted to engage the shoulder 102 on the collar 1111 when the pawl swings inwardly toward the axis of rotation of the roller 95. When the roller 95 is stationary or moving slowly and the pawl is arranged above the collar 1%, as illustrated in FIG. 14, the pawl 115 swings inwardly so that the shoulder 117 thereof engages the latch shoulder 1-02 on the collar 1111. When this occurs, rotation of the collar g5 in a rolling direction by the spring 111% is prevented. When, however, the roller is rotated rapidly, the pawl 115 swings outwardly by centrifugal force so that its shoulder 117 does not engage the shoulder 1112 on the collar 101, and under these conditions of rapid rotation the roller is rotated by the spring 1113 to roll the screen 31 thereon. By reason of the pawl 115 and the stationary collar 101, the screen 31 may be withdrawn downwardly from the screen case 92 and then latched in that position. When it is desired to retract the flexible screen 31 into the screen case $2, the screen 31 is given a tug and. allowed to retract rapidly into the screen case 92.

The form of the invention illustrated in FIGS. 11 to 15 also includes theopening 64 in the roller and the stop member 711 pivotally carried by the screen case 9 as described above in connection with the form of the invention illustrated in FIGS. 5 to 7 and like reference characters have been utilized for like parts. The stop member 751, which is in alignment with the opening 64 operates in conjunction With the opening 64 to prevent further rotation of the roller in the unrolling direction when the screen is unrolled therefrom to uncover th opening, i.e. to the last turn to prevent further unrolling of the screen from the roller. When the screen is rolled upon the roller 95, the opening 64- in the roller is covered by the screen rolled thereon, and thus the roller 95 may be freely rotated in the unrolling direction against the action of the spring 1133 to allow downward withdrawal of the flexible screen 31 from the screen case 92. When the flexible screen 31 is unrolled to the last turn, the opening 64 in the roller is uncovered and the stop member 76 is advanced into the opening by the spring 73. When this occurs, further rotation of the roller 95 in the unrolling direction is stopped to positively prevent tearing or separation of the flexible screen 31 from the roller 95. The roller 95 is then allowed to rotate slowly in a rolling direction until the shoulder 117 on the pawl engages the latch shoulder 162 on the collar 101, whereupon rolling rotation of the roller 95 is stopped and the screen is maintained in picture exhibiting position. It is noted that at least substantially degrees of rotation of the roller is provided between the point where the stop shoulder 74 on the stop member 70 engages the stop edge 65 of the opening 64, and the point where the latch shoulder 117 of the pawl 115 engages the latch shoulder 102 on the collar 161. This is to allow sufficient rotation of the roller in the unrolling direction to permit rapid rolling of the roller in the rolling direction so that, when it is desired to retract the screen into the screen case, the shoulder 117 of the pawl 115 will not engage the latch shoulder 102 on the collar 1131. This relationship of these parts assures correlated operations of the stop mechanisms which limit unrolling of the screen and which permit controlled rolling of the screen on the roller. By mounting the, pawl 115 on the bracket 1114 which bracket is fixed with respect to the opening 64 in the roller 95, these angular relations may be positively determined and maintained.

in all forms of the invention herein disclosed, there are provided cooperating members carried by the screen case and roller, which members are controlled with respect to each other by the screen on the roller, to allow unrolling of the screen from the roller to picture exhibiting position until the screen is unrolled to uncover the opening, i.e. to the last turn and then to stop further unrolling of the screen from the roller whereby tearing and separation of the screen from the roller are entirely eliminated. In the form of the invention contemplated in FIG. 3, this mechanism for limiting the unrolling 0f the screen from the roller also cooperates with the tensioning means associated with the suspension slat for providing a simple and effective arrangement for tensioning the screen so as to make it particularly adaptable for use in exhibiting three-dimensional pictures. In the form of the invention contemplated in FIGS. 11 to 15, this mechanism for limiting the unrolling of the screen from the roller operates in conjunction with other cooperataoeaese ing members carried by the screen case and the roller, which prevent slow rotation of the roller in the rolling direction but permit rapid rotation of the roller in the rolling direction for the purpose of maintaining the screen in picture exhibiting position, this being particularly desirable in a projection screen of the wall mounted type.

While for purposes of illustration, several forms f this invention have been disclosed, other forms thereof may become apparent to those skilled in the art upon reference to this disclosure and, therefore, this invention is to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a projection screen for use in exhibiting pictures and having a screen case, a spring actuated roller rtatably mounted in the screen case, a flexible screen secured at one end to the roller and being automatically roiled thereon and having a slat at its other end for unrolling the screen from the roller to picture exhibiting position, the improvement comprising, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only when the screen is unrolled to its last turn, a stop member pivotally carried by the screen case in alignment with the opening in the roller, spring means urging the stop member toward the roller against the outermost turn of the screen on the roller and advancing the stop member into the opening in the roller only when the roller is rotated in the unrolling direction to a position where the screen is unrolled to the last turn, said stop member having a stop shoulder engaging one edge of the opening in the roller when the stop member is advanced into the opening to stop further rotation of the roller in the unrolling direction and prevent further unrolling of the screen from the roller, and having cam means engaging another edge of the opening in the roller for retracting the stop member from the opening when the roller is rotated in the rolling direction to roll the screen upon the roller.

2. In a projection screen for use in exhibiting pictures and having a screen case, a spring actuated roller rotatably mounted in the screen case, a flexible screen secured at one end to the roller and being automatically rolled thereon and having a slat at its other end for unrolling the screen from the roller to picture exhibiting position, the improvement comprising, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only when the screen is unrolled to uncover the opening, a stop member pivotally carried by the screen case in alignment with the opening in the roller, spring means urging the stop member toward the roller against the outermost turn of the screen on the roller and advancing the stop member into the opening in the roller only when the roller is rotated in the unrolling direction to a position where the screen is unrolled to uncover the opening, said stop member having a stop shoulder engaging one edge of the opening in the roller when the stop member is advanced into the opening to stop further rotation of the roller in the unrolling direction and prevent further unrolling of the screen from the roller, and said stop member engaging another edge of the opening in the roller for retracting the stop member from the opening when the roller is rotated in the rolling direction to roll the screen upon the roller, said stop member also having wheel means engaging the screen rolled upon the roller to prevent wear during rolling and unrolling of the screen on the roller.

3. In a projection screen for use in exhibiting pictures and having a screen case, a spring actuated roller rotatably mounted in the screen case, a flexible screen secured at one end to the roller and being automatically rolled thereon and having a slat at its other end for unrolling the screen from the roller to picture exhibiting position, the improvement comprising, a latch shoulder stationarily carried by the screen case, a pawl rotatably carried by the roller and movable between advanced and retracted positions and having a shoulder engaging the latch shoulder when the pawl is in retracted position to prevent rotation of the roller in the rolling direction, said pawl being moved to its advanced position by centrifugal force when the roller is rapidly rotated to allow rotation of the roller in the rolling direction, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only when the screen is unrolled to uncover the opening, a stop member pivotally carried by the screen case in alignment with the opening in the roller, spring means urging the stop member toward the roller against the outermost turn of the screen on the roller and advancing the stop member int-o the opening in the roller only when the roller is ID- tated in the unrolling direction to a position where the screen is unrolled to uncover the opening, said stop member having a stop shoulder engaging one edge of the opening in the rolier when the stop member is advanced into the opening to stop further rotation of the roller in the unrolling direction and prevent further unrolling of the screen from the roller, and said stop member engaging another edge of the opening in the roller for retracting the stop member from the opening when the roller is rotated in the rolling direction to roll the screen upon the roller.

4. In a projection screen for use in exhibiting pictures and having a screen case, a spring actuated roller rotatably mounted in the screen case, a flexible screen secured at one end to the roller and being automatically rolled thereon and having a slat at its other end for unrolling the screen from the roller to picture exhibiting position, the improvement comprising, a latch shoulder stationarily carried by the screen case, a pawl rotatably carried by the roller and movable between advanced and retracted positions and having a shoulder engaging the latch shoulder when the pawl is in retracted position to prevent rotation of the roller in the rolling direction, said pawl being moved to its advanced position by centrifugal force when the roller is rapidly rotated to allow rotation of the roller in the rolling direction, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only when the screen is unrolled to uncover the opening, a stop member pivotally carried by the screen case in alignment with the opening in the roller, spring means urging the stop member toward the roller against the outermost turn of the screen on the roller and advancing the stop member into the opening in the roller only when the roller is rotated in the unrolling direction to a position where the screen is unrolled to uncover the opening, said stop member having a stop shoulder engaging one edge of the opening in the roller when the stop member is advanced into the opening to stop further rotation of the roller in the unrolling direction and prevent further unrolling of the screen from the roller, and said stop member engaging another edge of the opening in the roller for retracting the stop member from the opening when the roller is rotated in the rolling direction to roll the screen upon'the roller, the angular relations with respect to the axis of rotation of the roller between the latch shoulder and pawl and the stop shoulder and edge of the spring in the roller being such as to permit rapid rotation of the roller in the rolling direction from a position where the roller is stopped from rotation in the unrolling direction.

5. In a projection screen for use in exhibiting pictures and having a supporting stand, a screen case carried by the supporting stand, a spring actuated roller rotatably mounted in the screen case, a flexible screen secured at one end to the roller and being automaticlly rolled thereon and having a suspension slat at its other end for unrolling the screen from the roller to picture exhibiting position, and a hook member carried by the stand and spaced from the screen, the improvement comprising, means for releasably securing the suspension slat to the hook member in picture exhibiting position when the screen is unrolled from the roller and including means connected to the suspension slat for applying a greater tensioning force to the screen than can be applied by the spring actuated roller, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only when the screen is unrolled to uncover the opening, a stop member pivotally carried by the screen case in alignment with the opening in the roller, spring means urging the stop member toward the roller against the outermost turn of the screen on the roller and advancing the stop member into the opening in the roller only when the roller is rotated in the unrolling direction to a position where the screen is unrolled to uncover the opening, said stop member having a stop shoulder engaging one edge of the opening in the roller when the stop member is advanced into the opening to stop further rotation of the roller in the unrolling direction and prevent further unrolling of the screen from the roller, and said stop member engaging another edge of the opening in the roller for retracting the stop member from the opening when the roller is rotated in the rolling direction to roll the screen upon the roller, and manually controlled means operatively connected between the post and the handle member and hook member for moving the handle member and hook member apart and releasably locking them against movement toward each other when the screen is in picture exhibiting position and rotation of the roller in the unrolling direction is stopped by the stop member for tensioning the resilient means to tension the screen in picture exhibiting position.

6. In a projection screen for use in exhibiting pictures and having a supporting stand, a screen case carried by the supporting stand, a spring actuated roller rotatably mounted in the screen case, a flexible screen secured at one end to the roller and being automatically rolled thereon and having a suspension slat at its other end for unrolling the screen from the roller to picture exhibiting position, and a hook member carried by the stand and spaced from the screen, the improvement comprising, means for releasably securing the suspension slat to the hook member in picture exhibiting position when the screen is unrolled from the roller, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only when the screen is unrolled to uncover the opening, a stop member pivotally carried by the screen case in alignment with the opening in the roller, spring means urging the stop member toward the roller against the outermost turn of the screen on the roller and advancing the stop member into the opening in the roller only when the roller is rotated in the unrolling direction to a position where the screen is unrolled to uncover the opening, said stop member having a stop shoulder engaging one edge of the opening in the roller when the stop member is advanced into the opening to stop further rotation of the roller in the unrolling direction and prevent further unrolling of the screen from the roller, and said stop member engaging another edge of the opening in the roller for retracting the stop member from the opening when the roller is rotated in the rolling direction to roll the screen upon the roller.

7. In a projection screen for use in exhibiting pictures and having a screen case, a spring actuated roller rotatably mounted in the screen case, a flexible screen secured at one end to the roller and being automatically rolled thereon and having a slat at its other end for unrolling the screen from the roller to picture exhibiting position, the improvement comprising, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only When the screen is unrolled to uncover the opening, a stop member pivotally carried by the screen case in alignment with the opening in the roller, spring means urging the stop member toward the roller against the outermost turn of the screen on the roller and advancing the stop member into the opening in the roller only when the roller is rotated in the unrolling direction to a position Where the screen is unrolled to uncover the opening, said stop member having a stop shoulder engaging one edge of the opening in the roller when the stop member is advanced into the opening to stop further rotation of the roller in the unrolling direction and prevent further unrolling of the screen from the roller, and said stop member engaging another edge of the opening in the roller for retracting the stop member from the opening when the roller is rotated in the rolling direction to roll the screen upon the roller.

. In a projection screen for use in exhibiting pictures and having a screen case, a spring actuated roller rotatably mounted in the screen case, a flexible screen secured at one end to the roller and being automatically rolled thereon and having a slat at its other end for unrolling the screen from the roller to picture exhibiting position, the improvement comprising, said roller having an opening therein which is normally covered by the screen rolled thereon and which is exposed only when the screen is unrolled to uncover the opening, a stop member pivotally carrier by the screen case in alignment With the open ing in the roller, said stop member being normally urged toward the roller and against the outermost turn of the screen on the roller so as to be advanced into the opening in the roller only when the roller is rotated in the unrolling direction to a position where the screen is unrolled to uncover the opening, the stop member when advanced into the opening engaging one edge of the opening in the roller to arrest further rotation of the roller in the unrolling direction and to prevent further unrolling of the screen from the roller, rewinding of the screen upon the roller when the stop member is ad vanced into the opening causing another edge of the opening to engage the stop member to retract the stop member from the opening.

References Cited in the file of this patent UNITED STATES PATENTS 513,783 Hartshorn Jan. 30, 1894 2,099,068 Keithly Nov. 16, 1937 2,793,687 Petrick May 28, 1957