US3314468A - Retractable projection-screen assembly - Google Patents

Description

April 18, 1967 H. RIEDEL RETRACTABLE PROJECTIONSCREEN ASSEMBLY 4 Sheets-Sheet l Filed Nov. 18, 1965 @l wwe R MH e m H Filed Nov. 18, 1965 4 Sheets-Sheet 2 Herberr Riedel April 18, 1967 H. RIEDEI. 3,314,468

RETRACTABLE PROJECTON-SCREEN ASSEMBLY Filed Nov. 18, 1965 4 Sheets-Sheet 3 Fig. l0

Herber Riedel wat; -/erffrn v1/europ;

April 18, 1967 H. RIEDEL 3,314,468

RETRACTABLE PROJECTION-SCREEN ASSEMBLY Filed Nov. 18, 1965 4 SlleeLS-Sl'lee'fl 4 2g l Herbert Riedel United States Patent ice 3,314,468 RETRACTABLE PRGJECTION-SCREEN ASSEMBLY Herbert Riedel, Spitalmuhlenstr. 13, SchWabisch-I-Iall, Germany Filed Nov. 18, 1965, Ser. No. 508,488 Claims priority, application Germany, July 21, 1961, R 30,809 7 Claims. (Cl. i60-24) ABSTRACT GF THE DISCLOSURE The instant disclosure relates to a retractable projection-screen assembly in which a pair of horizontal members engage upper and lower horizontal edges of a projection screen and are carried by a mounting stand including a transverse element for stiifening and tensioning the screen, the stiiening element being engaged with a support member of resilient material.

This applic-ation is a continuation-in-part of my copending application Ser. No. 210,620 filed July 16, 1962, now Patent No. 3,233,658, granted Feb. 8, 1966.

In my copending applica-tion I have disclosed and claimed a collapsible projection-screen assembly wherein a generally rectangular projection screen of flexible sheet material is provided with a pair of support members respectively extending along its horizontal edges; each support member is fitted at its ends with a pair of sleeves which are attached to the screen and are braced against corresponding sleeves of the other support member so as to define four corners of a rectangle to which the screen is positively secured under vertical stress. In addition, the screen is also horizontally stressed by the provision of a control mechanism for one or both of the support members which for this purpose are of tubular shape, the control mechanism including :a tensioning rod which axially traverses the tubular member and is coupled with its two sleeves so as to vary 'their relative spacing in response to rotation of an operating knob on one of the sleeves. The resulting tensioning of the screen edges eliminates the formation of wrinkles in the screen fabric, so often encountered with prior projection-screen assemblies.

The principal object of this invention is to provide, in a projectionscreen assembly of the same general type as described above, improved means for mounting the two edge-supporting members on a stand with exertion of a vertical tensioning force upon the screen particularly in the vicinity of its lateral edges.

A more particular object of my present improvement is to provide means in such Aassembly for exerting upon one of the members, preferably the upper one, a restoring torque for rewinding the screen upon its unwinding from this member.

In accordance with this invention, a tubular support member anchored to a horizontal edge of a rectangular projection screen, particularly (but not exclusively) a screen designed for the projection of slides, is journaled in bearings on a horizontal beam of a mounting stand and is axially traversed by a rod about which a helical spring is coiled. One end of the spring is attached to the support member, the other end being secured to the mounting frame (advantageously through the intermediary of a stationary knob projecting from the tubular member) under sufficient stress to create a torque tending lto wind the entire screen on the tubular member. In use, the screen is unwound with the aid of an elongated second support member which is anchored to -the opposite horizontal M Patented Apr. I8, 1967 screen edge and is releasably held on the mounting stand by a suitable detent.

In line with the teachings of my earlier application, and for the purpose of supporting the screen mainly in the vicinity of the corners of its rectangular outline, I prefer to fasten the tubular upper support member to its mounting beam only at its extremities so that this member, made of resilient material, is free to flex between its engaged terminal portions; by the same token, the ends of the lower and likewise resilient support member are rmly gripped by an elongated, substantially coextensive stiftening rail which in a preferred embodiment is troughshaped and which at one or more points, conveniently near its center, is engageable with the aforementioned detent. The vertical distance between this detent and the beam carrying the upper support member may be arranged to be varied by suitable means.

According to a further feature of my invention, the detent is carried on an arm swingable about a horizontal axis disposed behind the unfurled screen so as to be retractable into an Vupturned position, after disengagement from the lower support member, in which the detent faces rearwardly and straddles a cent-ral column of the mounting stand whereby the assembly is formed into an easily transportable, compact unit. The column, in turn, may be provided with simila-rly retractable legs at its lower end.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a front-elevational view (parts broken away) of a projection-screen assembly according to the invention, with its screen in a partly extended position;

FIG. 2 is a side-elevational View of the assembly, taken partly in section on Ithe line II-II of FIG. 1, but showing the screen fully extended;

FIG. 3 is a cross-sectional view of the screen Iand its support members, taken on the line III-III of FIG. l but drawn to a larger scale;

FIG. 4 is an enlarged sectional view of a hinge element in an extended position also shown in FIG. 8;

FIG. 5 is a fragmentary cross-sectional view taken on the line V-V of FIG. 1 but showing the screen in rolledup position;

FIG. 6 is an enlarged sectional view of some of the elements shown at the upper right in FIG. l;

FIG. 7 is a view generally similar to FIG. 6 but relating to elements shown at upper left in FIG. 1;

FIG. 8 is a fragmentary side-elevational view similar to the centr-al part of FIG. 1 but showing the elements thereof in an alternate position;

FIG. 9 is a cross-sectional detail View taken on the line IX-IX of FIG. 2 but with the screen omitted;

FIG. 10 is a front-elevaton-al detail view taken on the line X-X of FIG. 2;

FIG. l1 is a side-elevational view complementing FIG. 2 and showing the lower part of a screen-supporting column;

FIG. 12 is a cross-sectional detail view taken on the line XII-XII of FIG. 11; and

FIG. 13 is a somewhat diagrammatic face view of the projection screen.

The assembly shown in the drawing comprises a flexible rectangular projection screen S2 anchored along its horizontal edges to an upper and a lower tubular support member generally indicated at 70 and '71, respectively. The upper member 70 is axially traversed by a tubular rod or core 72 around which a helical spring '73 is coiled. The member '70 is gripped at its two ends in respective sleeves 74 and 106 which are journaled in bearings 75 and 107, respectively, secured to the front face of an elongated transverse element represented by a horizontal carrier beam 76 on a vertical column 96. yAt the right-hand end of member 70, best seen in FIG. 6, the spring 73 terminates in a number of smaller turns of thinner wire 135 received in a bore 146 of a knob 77, having threads 147 in engagement with rod 72, the last of these turns being anchored at 136 in a slot 137 of this rod. The left-hand end of the spring 73 is secured, as best seen in FIG. 7, to a bushing 79 by being anchored at 78 to a stem 172 in line with rod 72; stem 1'72 embraces the left-hand end of rod 72 but is rotatable independently thereof and is fixed by a pin 189 to an adjusting knob S0 as well as to an extension 149 of bushing 79 which is received in a bore 108 of that knob. Bushing 79 is journaled in a bracket 112 on beam 76; this bracket, as best seen in FIG. 5, is formed with a releasable front strap 112:1 normally fastened to it by suitable means including one or more screws 148. A setscrew 81 on strap 112a serves to immobilize the sleeve 79, 149 together with knob $0 and stem 172 in a selected rotary position after the knob has been turned to loosen or tighten the spring 73 so as to impart to it the desired degree of stress; during such adjustment of left-hand knob S0, the right-hand knob 77 is held stationary together with rod 72 and the adjoining end of spring 73.

The bearings 75 and 107 are integral with resilient 'clips 134, as best seen in FIG. 2 for the bearing 75, which are engageable with the ends of lower support member 71 when the latter is raised into a retracted position illustrated in FIG. 5.

Screen S2 has its upper and lower edge portions formed into loops 85 and 91 by means of seams 83 and 84 (FIG. 3). The upper loop 85 surrounds an inner tube 88 and is surrounded by an outer tube 87 forming part of the support member 70, inner tube S8 and loop S5 being slid endwise into the coaxial outer tube 87 which is formed with a longitudinal slot 89 for thebody of screen 82. Bushings 90 and 90', FIGS. 6 and 7, maintain the spacing between the nested tubes on opposite sides of loop 85. The ends of outer tube 87 are inserted into the sleeves 74 and 106, the latter sleeve being cemented or otherwise rigidly secured to knob 77, and the frictional connection between the sleevesV and the outer tube may be supplemented by additional fastening means not shown. Sleeves 74 and 106 are provided with screw-threaded flanges 74a and 106e by which they are held engaged with their respective bearings 75 and 107.

The lower loop 91 of screen 82 is slid around a tube 92 forming part of the support member 71, the ends of this tube being received in sleeves 133 and 133 having knobs 97 and 97 fastened thereto; these knobs facilitate the unfurling of screen S2, initially wound on member 70, by exertion of a downward pull upon'rmember 71. A trough-shaped stilfening rail 102, with an internal diameter slightly greater than the outer diameter of tube 92 together with loop 91, surrounds the member 71 over an arc of approximately 270 so as to leave an annular clearance 113 therebetween, see FIG. 3. Beyond the screen 82 this clearance is occupied by shoulders 114, 114' on the ends of tube 92 so that rail 102 firmly engages the member 71 at these ends; the shoulders 114, 114' may be formed integral with tube 92 or as separate sleeves placed thereon. The end sleeves 133 and 133 are tted under pressure around the rail 102 as seen in FIG. 2. Member 71 is thus allowed to flex upwardly, within the limits imposed by the overhanging edges 103 of rail 102, between shoulders 114, 114 even as member 70 is free to flow downwardly between bearings 75 and 107.

The central column 96, as best seen in FIG. 2, carries three collars 95, 93 and 195 of which the upper two, i.e. collars 95 and 93, are fixed whereas the lower collar 195 is vertically slidable. The latter collar is formed integral with a set of resilient tongues 194 rictionally holding it at a selected elevation. Collar 95 removably carries 'the beam 76 which is upwardly extended into a semicyclindrical shield 93 overlying the upper half of the support member 70. A backing plate 138 (FIGS. 2, 5 and 10), rigid with this collar, is formed with a pair of slots 139 designed to receive headed studs 94 which project rearwardly from the beam 76; the beam and the screen support 70, 71, assembled thereon in the manner illustrated in FIG. 5, may'thus be detached from the column 96 of the projector stand for storage or transportation.

The middle collar 93 has attached to it a hinge element 111, best seen in FIGSQ-l and 8. This hinge element is a strip of highly ilexible plastic material provided with two transverse incisions 156 which divide it into three parts interconnected by thin webs 104. The hinge 111 can thus be readily bent from a straight position (FIG.

8) into a doubled-up position (FIG. 2), thus through an angle of 180, with adjoining sections including angles of only 90, so that the webs 104 are not unduly stressed and will stand up even after many bendings. The swingable end section of hinge 111 is cemented or otherwise fastened onto a rocker arm 118 which in use occupies a depending position illustra-ted in full lines in FIG. 2. Arm 118 bears a lug 97 engageable by Va skirt 131 on slidable collar 195 which can be moved downwardly along column 96 to lock the arm 118 in its depending position. A slider 99 embraces theV arm 118 and has a threaded bore 153 matingly engaged by a spindle 100 which is lodged in a pair of lugs 154, 155 rigid with arm 118; spindle 100 has a milled head 101 by which it may be turned to raise or lower the slider with reference to the arm 118. A bracket 90 is fastened to the slider 99 by a pair of resilient pins 191 (see also FIG. 9) enabling the bracket to be swungsoutwardly, as indicated by arrow `151 in FIG. 2, against the elastic restoring force of these pins.

Bracket carries a pair of detents 98 which co-operate with a confronting ledge 9S on slider 99 to engage the central portions of edges 103 of rail 102 when the lower support member 71 is to be held in its operative position in which the screen S2 is unwound from upper member 7 il against the force of its own restoring spring 73. The exact level of member 71 may be adjusted by turning the head 101. After the member 71 has been released from its detents 9S, 9S by an outward deflection of bracket 90, spring 73 pulls this member up into engagement with clips 134 while coiling the screen S2 about member 70, as shown in FIG. 5. Thereafter, upon an upward sliding of collar 195 to disengage lug 97, rocker arm Vmay be swung up (arrow 132 in FIG. 2) into a retracted position, illustrated in dot-dash lines, in which its head 101 is gripped by a spring clip 105 on column 96.

The mounting of the extended screen 82 on two tubular member 79V and 71, each supported only at its ends, results in an incurving of the screen edges as has been indicated diagrammatically and with some exaggeration in FIG. 13. The screen is thus stressed mainly diagonally and its central area 143 is, for practical purposes, completely -iiat so that slides, motion pictures or the like can be projected thereon without distortion.

As illustrated in FIGS. 11 .and 12, the lower end of column 96 is formed with a set of radially extending legs 119 each articulated to a base 120 Aof the column by being hinged with the aid of a pin 125 to a flat head 124 of a pivotal stud 123 which is rotatably received in a respective radial bore 122 of the base. As here shown, :base is formed as an entity separate from column 96, an upstanding'ilange 121 thereof constituting a socket for the column which may be secured to it, if necessary, by a setscrew not shown. It is preferred to have four legs 119 extend 90 separate from the base 120, only two such legs being visible in FIG. 11.

Each of the legs 119 advantageously consists of a moderately resilient thermoplastic material which may be internally reinforced by inserted metal strips or the like, eg. as shown at 128 in FIG. 12. The prolile of the legs forms a pair of side anges 129 whose tips 127 rest on the ground while an upstanding spur 126 of the leg contacts the outer surface of base flange 121. The angle included Ibetween the spur 126 and the undersurface of the leg is somewhat greater than 90 so that the legs are slightly inclined with reference to the horizontal, the bottom edge 130 of base 120 being thereby held elevated above the ground. This edge 130 projects, however, below the connected ends of the legs so as to come to rest on the ground when the legs 119 are deformed by an excessive load, thereby preventing dam-age to these legs.

Each leg 119 may be individually rotated through an angle of 180 about the axis of its stud 123 from its operative position, illustrated in full lines for the right-hand leg of FIG. l1, into a reversed position in which the spur 126 points downwardly (dot-dash lines) and from which the leg may be swung up into a retracted position alongside column 96 as illustrated for the left-hand leg in FIG. 11. With all four legs so retracted, the stand constituted by these legs and by column 96 occupies relatively little storage space.

I claim:

1. A projection-screen assembly comprising a flexible projection screen of substantially rectangular outline with upper and lower horizontal edges; a mounting stand for said screen provided with an elongated transverse element; a tubular first support member engaging said screen along one of said edges, said tubular member being rotatably journaled on s-aid transverse element, an elongated second support member engaging said screen along the other of said edges; detent means on said stand releasably engageable with said second support-member for holding said support members vertically spaced apart, thereby maintaining said screen in an unfurled state; and spring means within said tubular member anchored to the latter and to said transverse element for exerting upon said tubular element in the unfurled state of said screen a torque tending to wind said screen around said tubular member, said transverse element being provided with a pair of horizontally spaced-apart bearings rotatably engaging respective terminal portions of said tubular member, the latter consisting of resilient material and being free to ex between said terminal portions, said second support member also consisting of resilient material and being provided with an elongated stifiening element substantially coextensive therewith, said stiiening element gripping the ends of said second support member while leaving same free to flex between said ends, said detent means being engageable with said second support member through the intermediary of said stitening element, said stifening element being constituted `as a trough-shaped rail surrounding said second support member with clearance, except at said ends, over an arc greater than 180.

2. An assembly las defined in claim 1 wherein said tubular member is provided with a rod passing axially therethrough, said spring means comprising a helical spring coiled about said rod and having extremities anchored on opposite ends of said tubular member to the latter and to said transverse element, respectively.

3. An assembly as defined in claim 1 wherein said detent means is engageable with said stiftening element substantially at the center thereof.

4. A projection-screen assembly comprising a exible projection screen of substantially rectangular outline with upper and lower horizontal edges; a mounting stand for said screen provided with an elongated transverse element; a tubular first support member engaging said screen along one of s-aid edges, said tubular member being rotatably journaled on said transverse element, an elongated second support member engaging said screen along the other of said edges; detent means on said stand releasably engageable with said second support mem-ber for holding said support members vertically spaced apart, thereby maintaining said screen in an unfurled state; and spring means within said tubular member anchored to the latter and to said transverse element for exerting upon said tubular element in the unfurled state of said screen a torque tending to wind said screen around said tubular member, said transverse element being provided with a pair of horizontally spaced-apart bearings rotatably engaging respective terminal portio-ns of said tubular member, the latter consisting of resilient material and being free to ex between said terminal portions, said second support member also consisting of resilient material and being provided with an elongated stilening element substantially coextensive therewith, said stiffening element gripping the ends of said second support member while leaving same free to flex between said ends, said detent means being engageable with said second support member through the intermediary of said stiffening element, said detent means being engageable with said stittening element substantially lat the center thereof, said stand comprising a central column rigid with said transverse element and provided with an arm pivotally secured thereto for swinging about a horizontal axis, said detent means being disposed on the free end of said arm and being bifurcated for straddling said column upon a swing of said arm about said axis.

5. An assembly as defined in claim 4 wherein sai-d arm is provided with a threaded extension carrying said detent means, said extension being adjustable for varying the distance of said detent means from said transverse element.

6. An assembly as defined in claim 4 wherein said arm is secured to said column by a flexible hinge element, said second support member being anchored to the lower edge of said screen for keeping same unfurled upon being engaged by said detent means in a depending position of said arm.

7. An assembly as defined in claim 4 wherein said column has a lower end provided with a plurality of radially extending legs each having a pivotal stud securing it to said column, each leg being rotatable about its stud through an angle of 180 into an inverted position enabling its retraction into an upwardly swung position alongside said column.

References Cited by the Examiner UNITED STATES PATENTS 2,530,877 11/1950 Heck et al. 160-24 3,036,628 5/ 1962 Nichol-as 160-24 3,166,115 1/1965 Riedel 160-24 3,179,161 4/1965 Johnson 160-3 13 HARRISON R. MOSELEY, Primary Examiner, I. K. BELL, Assistant Examiner,

Claims (1)

1. A PROJECTION-SCREEN ASSEMBLY COMPRISING A FLEXIBLE PROJECTION SCREEN OF SUBSTANTIALLY RECTANGULAR OUTLINE WITH UPPER AND LOWER HORIZONTAL EDGES; A MOUNTING STAND FOR SAID SCREEN PROVIDED WITH AN ELONGATED TRANSVERSE ELEMENT; A TUBULAR FIRST SUPPORT MEMBER ENGAGING SAID SCREEN ALONG ONE OF SAID EDGES, SAID TUBULAR MEMBER BEING ROTATABLY JOURNALED ON SAID TRANSVERSE ELEMENT, AN ELONGATED SECOND SUPPORT MEMBER ENGAGING SAID SCREEN ALONG THE OTHER OF SAID EDGES; DETENT MEANS ON SAID STAND RELEASABLY ENGAGEABLE WITH SAID SECOND SUPPORT MEMBER FOR HOLDING SAID SUPPORT MEMBERS VERTICALLY SPACED APART, THEREBY MAINTAINING SAID SCREEN IN AN UNFURLED STATE; AND SPRING MEANS WITHIN SAID TUBULAR MEMBER ANCHORED TO THE LATTER AND TO SAID TRANSVERSE ELEMENT FOR EXERTING UPON SAID TUBULAR ELEMENT IN THE UNFURLED STATE OF SAID SCREEN A TORQUE TENDING TO WIND SAID SCREEN AROUND SAID TUBULAR MEMBER, SAID TRANSVERSE ELEMENT BEING PROVIDED WITH A PAIR OF HORIZONTALLY SPACED-APART BEARINGS ROTATABLY ENGAGING RESPECTIVE TERMINAL PORTIONS OF SAID TUBULAR MEMBER, THE LATTER CONSISTING OF RESILIENT MATERIAL AND BEING FREE TO FLEX BE-

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