Lid raising means for a jack-in-the-box projection television receiver

A lid-raising device is disclosed for use in an ultra-compact, jack-in-the-box television receiver housed in an open-topped cabinet. The cabinet has a lid pivotally attached at the back thereof for selectively opening and closing the cabinet for emergence and storage of a unitary optical assembly elevatable from and nestable within the cabinet by a precision elevating device, and includes a rear-projection screen for displaying a television image upon its emergence. The unitary optical assembly includes a rigid, box-like shroud having a slanted back and an open front for receiving and supporting the screen. The lid-raising device comprises an assembly of at least one cam element and a captivated cam-follower element for slidably attaching the lid to the shroud such that as the unitary optical assembly is elevated and lowered by the precision elevating device, the lid-raising device is effective to raise and lower the lid in relatively friction-free sliding association while holding the lid apart from rubbing contact with the shroud.

CROSS-REFERENCE TO RELATED APPLICATIONS 
This application is related to but in no way dependent upon copending 
applications of common ownership herewith including: Ser. No. 228,434 
filed Jan. 26, 1981; U.S. Pat. No. 4,349,845; Ser. No. 238,861 filed Feb. 
27, 1981; Ser. No. 235,059 filed Feb. 17, 1981, now U.S. Pat. No. 
4,358,792. 
BACKGROUND OF THE INVENTION AND PRIOR ART DISCLOSURES 
This invention concerns television systems, and is particularly directed to 
a system in which a rear projection screen, storable in the system 
cabinet, is elevatable for viewing. 
A system of this type is described and fully claimed in referent copending 
application Ser. No. 228,434. A jack-in-the-box projection television 
receiver comprises cabinet means for enclosing the components of the 
receiver, and includes lid means hinged at the back of the cabinet. The 
receiver comprises vertically arranged, elevatable rear projection screen 
means selectively storable in the cabinet. Image source means provides for 
forming a television image. Stationary projection means provide for 
projecting an aerial image of a television image formed by the image 
source means along a folded optical path onto the screen means when the 
optical path is erected and the screen means is located a predetermined 
image projection distance from the source means. The receiver further 
includes means for elevating the screen from a first receiver-inoperable 
position wherein the screen means is completely enclosed within the 
cabinet and the receiver is ultra-compact, to an elevated 
receiver-operable position wherein the screen means is emerged from the 
cabinet. As a result, the optical path is extended to a length equal to 
the predetermined image projection distance whereby the projection image 
is coincident with the screen. 
OBJECTS OF THE INVENTION 
It is a general object of this invention to provide means for lifting and 
lowering the lid of a cabinet of a projection television receiver wherein 
a viewing screen is elevated from the cabinet for viewing. 
It is a more specific object of this invention to provide means for lifting 
and lowering the lid of the ultra-compact, jack-in-the-box projection 
television receiver described and claimed in referent copending 
application Ser. No. 228,434. 
BRIEF DESCRIPTION OF THE DRAWINGS 
The appended claims set forth those novel features believed characteristic 
of the invention. However, the invention itself, as well as further 
objects and advantages thereof, will best be understood by reference to 
the following detailed description of a preferred embodiment taken in 
conjunction with the accompanying drawings, in which:

DESCRIPTION OF THE PREFERRED EMBODIMENT 
An ultra-compact jack-in-the-box projection television receiver 10 
according to the invention disclosed in referent copending application 
Ser. No. 228,434 is shown by FIG. 1A. The receiver comprises open-topped 
cabinet means 12 for housing the components of the receiver. Cabinet 12 
has lid means 14 pivotally attached at the back of the cabinet; the pivot 
may consist of at least one hinge 16 which may comprise a piano hinge, for 
example. The lid 14 is depicted as having an overhanging control panel 18 
for covering a receiver control panel. Grilled aperture ports 20 provide 
for audio emission from concealed speakers of a stereo sound system, for 
example. 
With reference now to FIG. 1B, lid 14 is shown as being raised and a 
unitary optical assembly means 22 is shown as being emerged from cabinet 
means 12. Control panel 24, which may include all standard television 
receiver front panel controls such as controls for channel selection, 
audio volume, and various chromatic controls, is exposed by the raising of 
control panel cover means 18 when lid 14 is raised by means as will be 
described. Control panel cover 18 is shown as being hingedly dependent 
from lid 14, as indicated. Control panel cover means 18 is described and 
claimed in referent copending U.S. Pat. No. 4,349,845. 
Unitary optical assembly means 22 is selectively storable in cabinet 12, 
and elevatable therefrom. Lid 14 provides for selectively opening and 
closing cabinet 12 for emergence and storage of unitary optical assembly 
22. The unitary optical assembly 22 includes rear projection screen means 
26 for displaying upon emergence a television image projected by receiver 
10. The unitary optical assembly 22 (see FIG. 2) further includes rigid, 
box-like shroud means 28, which has an open front for receiving and 
supporting screen 26, as depicted. Shroud 28 has a slanted back section 29 
as shown and has closed sides and a closed top. Shroud 28 is preferably 
made of high-impact polystyrene formed in a pressure mold. The material is 
essentially a "structural foam" that provides strength and rigidity with 
light weight. The raw color as molded is preferably dark chocolate brown 
having minimum light reflectivity. 
The unitary optical assembly 22 provides, by means of shroud 28, for 
maintaining screen 26 in a predetermined fixed relationship with internal 
projection optical components of receiver 10 (not shown) when screen 26 is 
elevated from cabinet 12. The unitary optical assembly is fully described 
and claimed in referent copending application Ser. No. 238,861. Cabinet 
extension 30 provides additional space for enclosing shroud 28 when 
elevatable assembly 22 is stored. 
Unitary optical assembly 22 is elevatable from and nestable within cabinet 
12 by precision elevating means. The precision elevating means also 
provides for opening and closing cabinet 12 by raising or lowering lid 14 
for emergence and storage of the unitary optical assembly, as will be 
shown. 
FIG. 3 depicts means for elevating unitary optical assembly 22 from a 
first, receiver-inoperable position wherein screen 26 is stored in cabinet 
12, to a second receiver-operable position wherein screen 26 is emerged 
from cabinet 12. Four vertically oriented and vertically stabilized screw 
means 32, for example, are shown as providing for elevating and lowering 
screen 26. Shroud 28 is shown as cut away in the left-hand side of FIG. 3 
to show details of the elevating means; an identical mirror image assembly 
is located on the opposite side of the cabinet 12, but partially obscured 
by screen 26, as depicted. 
The rotation of screw means 32 is translated into vertical movement by 
screw follower means 34 attached to bracket 36, to which shroud 28 is in 
turn attached. Guide rods 38 provide for vertically stabilizing shroud 28 
in its vertical traverse. Screen 26 is depicted as being in its raised 
position. 
Screw means 32 are caused to rotate in unison by power train means 
indicated as comprising screw means drive pulleys 40 which are caused to 
rotate in unison by drive pulley link belts 42. Drive pulleys 40 are in 
turn linked by belts 44 to drive pulleys 46 which are rotated by a 
reversible electrical motor 48. Belts 42 and 44 are depicted as being of 
the synchronous type for mating with synchronous pulleys 40 and 46, 
providing positive drive. The precision elevating means are fully 
described and claimed in the referent copending application Ser. No. 
235,059 now U.S. Pat. No. 4,358,792. 
The elevating of the unitary optical assembly 22 and associated screen 26 
from a stored, first receiver-inoperable position wherein screen 26 is 
emerged from cabinet 12, results in a large influx of air into cabinet 12, 
and when unitary optical assembly 22 is lowered for storing, a large 
efflux of air. To provide for the unimpeded influx and efflux of air, a 
capacious vent 50 is provided in the slanted back 29 of shroud 28, as 
depicted in FIG. 4. A spun-glass filter (not shown) inhibits entrance of 
contaminants. 
FIG. 4 also depicts lid-raising means 52 according to a preferred 
embodiment of the invention which, in conjunction with the precision 
elevating means described supra, provides for raising and lowering lid 14 
to selectively open and close cabinet 12. Lid-raising means 52 preferably 
comprises an assembly of at least one cam element 54 including a track 55 
shown as being attached to shroud 28, and a captivated cam-follower 56, 
which in this embodiment provides for attachment to lid 14 (not shown in 
FIG. 4). The lid-raising means according to the invention provides for 
slidably attaching lid 14 to shroud 28 such that, as the unitary optical 
assembly 22 is elevated and lowered by the precision elevating means, the 
lid-raising means 52 is effective to raise and lower lid 14, while holding 
lid 14 apart from rubbing contact with shroud 28. 
FIGS. 5A-5D comprise a series of views showing a sequence of the 
relationships of the associated elements of cabinet 12 and lid-raising 
elements according to the invention as the lid 14 is raised or lowered. 
With specific reference to FIG. 5A, lid 14 will be noted as being in two 
sections--a first section 14A for covering the open top of cabinet 12, and 
a second section 14B extending at an angle from first section 14A and 
permanently attached thereto, as depicted. Second section 14B provides for 
covering cabinet extension 30, and is shown as being pivotally attached to 
cabinet extension 30 by hinge 16. Cam-follower element 56 is attached to 
second section 14B, as depicted. 
In FIG. 5A, cam-follower element 56 is depicted as being in Position A with 
respect to cam element 54; in this Position A, unitary optical assembly 22 
is nested in cabinet 12 and lid 14 is closed. FIG. 5B depicts Position B 
of the lid raising means according to the invention in response to the 
activation of the precision elevating means described supra; it will be 
noted that although cam-follower element 56 has travelled a relatively 
short distance with respect to cam element 54, there has been an initial 
quick rise of lid 14, the reason for which will be explained. 
FIG. 5C depicts Position C of cam-follower element 56 wherein element 56 is 
well along in its excursive path along cam element 54, with the result 
that lid 14 is open about half-way. Final Position D, wherein the 
cam-follower element 56 is shown as being at the end of its excursion, and 
wherein the lid 14 is fully open, is shown by FIG. 5D. Unitary optical 
assembly 22 is shown as being fully emerged from cabinet 12, and the 
rear-projection screen 26 is in position to display a television image 
projected by internal optical components (not shown). 
FIGS. 6A-6C and FIG. 7 depict the preferred embodiments of cam element 54 
and cam-follower element 56, and show in detail the relationships of 
elements 54 and 56 in Positions A-D. Cam element 54, shown in elevation in 
FIG. 6A, is indicated as comprising a track 55 medially attached to the 
slanting back 29 of shroud 28, and having longitudinally oriented 
oppositely facing groove cams 58 and 60 for captivating inwardly facing 
grove-cam-follower members 62 and 64 of cam-follower element 56. A series 
of cut-out sections 57 in cam element 54 provide for lightness, and the 
truss-like construction depicted provides strength. Cam element 54 is 
indicated as being attached in this embodiment of the invention to the 
slanted back 29 shroud 28, and cam-follower element 56 as being attached 
to lid 14. By captivating track-travelling cam-follower element 56 as 
shown, the lid-raising means according to the invention is effective to 
retain lid 14 in predetermined spaced association to shroud 28. By this 
means, there is no possibility of lid 14 opening farther than the desired 
fully open position D, shown by FIG. 5D. Otherwise, it would be possible 
for lid 14 to fall backwards due to accidental contact or other undesired 
impetus. 
The initial quick rise of lid 14 according to the invention is attained 
during Position B depicted by FIG. 5B. With reference also to FIG. 6A 
wherein the associated cam elements are also depicted in Position B, the 
quick-rising force is applied to the cam-follower element 56 by upstanding 
spur 66, depicted as projecting steeply upwardly from the track 55 of cam 
element 54. As the lid is raised by the precision elevating means as 
described, spur 66 comes into contact with the floor 68 of cam-follower 
element 56, nudging cam-follower element 56 sharply upwardly, and 
providing the desired initial abrupt rise. The floor 68 of cam-follower 
element 56 is also shown in a plan view in FIG. 8. As the lid 14 continues 
to rise, floor 68 of cam-follower element 56 continues to ride on spur 66 
to the point where spur 66 blends into the top counter of track 55 of cam 
element 54, as depicted. Cam-follower members 62 and 64 thereafter provide 
for the lid-raising excursion of cam-follower element 56 by following 
respective groove cams 58 and 60. 
The gap 67 in the track 55 provides for quick disengagement of cam-follower 
element 56 from cam element 54. This feature simplifies removal of lid 14 
for servicing of components within the cabinet 12. 
The lid-raising means 52 according to the invention is not limited to one 
medially-located assembly, as has been depicted. As shown by FIG. 9, two 
lid-raising means 70 and 72 may be used, each spacedly located adjacent to 
the edge of lid means 14, as depicted. The use of two such lid-raising 
means can be efficaceous in applications in which the attached parts such 
as the lid and shroud are, for example, relatively large and heavy. 
To provide relatively friction-free operation, cam element 54 and 
cam-follower element 56 are preferably molded from dissimilar plastics. 
For example, the cam element 54 may be molded from nylon, and cam-follower 
element 56 from Delrin (R). By the use of such materials, lubricants are 
not required and relatively long, friction-free operation is assured. Cam 
element 54 may be attached to shroud 28 by a suitable adhesive. 
Cam-follower element 56 may be attached to the lid 14 by wood screws 
means. 
Exemplary dimensional heighth (H), width (W) and depth (D) values of the 
cabinet 12 of the projection television receiver, and components of the 
preferred embodiment of the invention described heretofore, are listed as 
follows. Reference numbers are in parentheses. It is to be recognized that 
the values are by way of example only, and are intended to be in no way 
limiting. The dimensional values and approximations are in inches, unless 
otherwise noted. 
Cabinet (12) 
Screen stored: 31H.times.44W.times.19.5D 
Height, screen elevated: 58 
Cabinet Extension (30) 26.5H.times.42W.times.8.5D 
Lid (14) 
First section (14A): 44W.times.20D 
Second section (14B): 38W.times.7.5D 
Control Panel Cover (18) 
6H.times.38W 
Shroud (28) 
28.7H.times.37.6W 
Depth, at bottom: 23.1 
Depth, at top: 17.5 
Angle of slanted back section (29), with respect to vertical: 30 degrees 
Length of slanted back section (29): 23.3 
Cam Element (54) (See FIGS. 6A, 6B and 7.) 
3.8H.times.2.0W.times.21.5L 
Height of each groove cam (58 and 60) 
Ref. No. 74: 0.5 
Width of track, Ref. No. 76: 0.7 
Height of spur (66) above track: 0.31 
Length of track (55): 18.7 
Cam-follower Element (56) 
1.9H.times.2.6W.times.4.6L 
While particular embodiments of the invention have been shown and 
described, changes and modifications may be made without departing from 
the invention in its broader aspects, and therefore, the aim of the 
appended claims is to cover all such changes and modifications as fall 
within the true spirit and scope of the invention.