US 3504643 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
April 7, 1970 F BURST ET AL 3,504,643
OVERBED TABLE Filed Sept. 26, 1966 5 Sheets-Sheet@ April 7, 1970 F, 1 BURST EI'AL OVERBED TABLE Filed Sepf. 2e, 196e 3 Sheets-Sheet April 7, 1970 F. J. BURST ET AL OVERBED TABLE 3 Sheets-Sheet 3 Filed Sept. 26, 1966 (ya e? 5v fm nw? i n MM www a@ United States Patent O U.S. Cl. S-144 9 Claims ABSTRACT OF THE DISCLOSURE An overbed table rendered safe for use with electrically operated hi-low hospital beds by a lock mechanism that prevents downward movement of the table even though it be heavily overloaded, together `with manually operable mechanism for unlocking the table and moving the same downwardly.
BACKGROUND OF THE INVENTION This invention relates to overbed tables and has for its principal object the provision of a new and improved table of this type.
The present invention provides a crank-operated, springassisted overbed table, which is equipped with a lock mechanism that denitely prevents lowering the table, except through an operation of the crank, while permitting free upward movement of the table responsive to an application of a small force acting upwardly thereon.
Prior art overbed tables, of which we are aware, are of two general types; namely, crank-operated and springassisted. In crank-operated tables, once the table is moved to a particular position, it is locked and cannot be moved either upwardly or downwardly until the crank is operated. In prior art spring-assisted tables, downward movement of the table is resisted by a brake mechanism which, in certain tables, permits upward movement of the table without releasing the brake. In other tables of this type, a brake-releasing lever must be operated before the table can be moved in either direction.
When used in connection with an electrically-operated hospital bed of the hi-low variety, discomfort and possible injury to the patient can result when the spring frame of the bed is elevated while the table is positioned thereover. A small upward movement of the spring frame of the bed brings the patient into contact with the overhanging portion of the table, and if the table is locked, further upward movement of the spring frame requires lifting the entire table. Since these tables are quite heavy, lifting the entire table imposes a considerable weight upon the patient. Certain spring-assisted overbed tables of the prior art provide a lever disposed beneath the table which must be operated upwardly to release the brake mechanism of the table. However, these releasing levers are not extended the full length of the overhanging portion of the table and it is possible for a patient to engage the table without operating this lever. In tables in which the brake mechanism permits upward movement without specific release of the brake, this danger of injury to the patient is minimized.
Certain electrically-operated hi-low hospital beds are provided with a lower frame which is not elevated when the spring frame is elevated, and as a result, the patient in such a bed may be squeezed after a slight upward movement of the table brings the floor-engaging portion thereof into contact with the non-elevatable portion of the bed.
The present invention provides a table having a constant force spring, the strength of which is insufficient to elevate the table even when the table is empty. A crank is provided and a cable employed to augment the force of the spring when the crank is operated in one direction, thereby to elevate the table, and when the crank is operated in the ICC- reverse direction, the table is pulled downwardly against the force of the spring. The table of the present invention is provided with a lock mechanism which definitely prevents downward movement of the table, even though it be heavily overloaded, except through an operation of the crank to unlock the locking mechanism and thereafter lower the table. The lock mechanism is arranged so that the table may be elevated while locked through the application of a small upward pressure thereupon. Through this arrangement, should the patient be elevated into contact with the overhanging portion of the table by upward movement of the spring frame of the bed, only a slight force is necessary to elevate the table and the discomfort of the patient is greatly reduced and the chances of injury to the patient are eliminated.
SUMMARY OF THE INVENTION This invention provides an overbed table that can be used over an electric hospital `bed with safety. The movable upper section of the table is urged upwardly by a constant force spring means that is not quite strong enough to overcome the force of gravity acting on the section. The force of the spring means is transmitted to the upper section by a presser tube which carries a sheave journaled near the spring means. A shaft journaled in the upper section carries a lock mechanism which prevents counterclockwise rotation of the shaft while permitting free clockwise rotation thereof. A cable section wound clockwise around a drum xed upon the shaft extends therefrom around the sheave to a point of attachment to the lower section of the table. A second cable section extends from said point of attachment to said drum around ywhich it is wound Counterclockwise, said first cable section preventing downward movement of the top section when counterclockwise rotation of the shaft is prevented by said lock. Counterclockwise rotation of a crank on said shaft unlocks said lock mechanism and frees the shaft to permit lowering the upper section by winding the second section of the cable upon said drum. The upper section is equipped with a pair of mirrors that are spring pressed into operative position as the table top is moved laterally to expose the contents of a tray.
It is a main object of the invention to provide an overbed table that is safe under all conditions encountered during its use.
Another object of the invention is to provide an overbed table of rugged construction that can be operated easily from one position to another by a patient.
Further objects of the invention, not specifically mentioned here, will be apparent from the detailed description and claims which follow, reference being had to the accompanying drawings in which a preferred embodiment of the invention is shown by way of example and in which:
FIG. 1 is a perspective view of an overbed table embodying the teachings of the invention;
FIG. 2 is an end elevational view, partly in section, and showing the upright post portion of the table;
FIG. 3 is a side elevational view, partly in section, and showing further details of the post structure;
FIG. 4 is a cross-sectional view taken substantially along the line 4 4 of FIG. 2, looking in the direction of the arrows and drawn to an enlarged scale;
FIG. 5 is an edge view of a stationary lock plate;
FIG. 6 is a plan view of the lock plate;
FIG. 7 is an edge view of a lock housing;
FIG. 8 is a plan view of the lock housing;
FIG. 9 is an end view of the cable drum;
FIG. l0 is a plan view of the cable drum;
FIG. 11 is a fragmentary cross-sectional view taken along the line 11-11 of FIG. 2, looking in the direction of the arrows and drawn to an enlarged scale;
FIG. 12 is a cross-sectional view taken along the line 12-12 of FIG. 11 looking in the direction of the arrows and drawn to an enlarged scale;
FIG. 13 is a plan view of the overbed table frame;
FIG. 14 is an elevational view with the tray and top in place;
FIG. l5 is a plan view of the tray; and
FIG. 16 is a cross-sectional view taken along the line 16-16 of FIG 15 looking in the direction of the arrows and drawn to an enlarged scale.
As will be seen in FIG. l, the overhead table consists of a base section comprising end members and 11 between which an intermediate member 12 is extended to form a generally H-shape floor-engaging portion of the table. Members 10, 11 and 12 are joined together in convenient manner such as by welding and preferably are composed of tubing. Casters 13 are mounted at the extremities of the members 10 and 11 to support the same upon a floor.
Upstanding from the junction of base members 10 and 12 is a lower post 15. As will be seen in FIGS. 1 and 4, post 15 is formed of two unequal U-shaped members telescoped together with the flanges of the smaller member attached to the end portions of the larger member. The web of the smaller member forms the wall of an outwardly opening channel 16. These members are welded together and to the base members y10 and 12. The lower section of the table is not elevated by an operation of the table.
Telescoped over the lower post 15 is an upper post 17 to the top of which the table-supporting frame 18 and table top 19 are located. Fixed at the upper end of the post 17 is a housing 20, in which the crank mechanism of the table is positioned. The upper section of the table thus formed is movable vertically with respect to the lower section.
As will be seen best in FIGS. l1 and l2, a base plate extends between opposite walls of the housing 20 and is fixed thereto preferably by welding. Upstanding from plate 25 intermediate the ends thereof is a bracket 26. Fitted in aligned perforations in the wall of housing 20 and in the bracket 26, are bushings 27 and 27A in which a shaft 28 is journalled. Shaft 28 extends out of the housing through a perforation in the opposite wall thereof.
Fixed on the wall of housing 20 through which the shaft extends is a lock plate 30 that contains a circular perforation, the center of which coincides with the axis of the shaft. As will be seen best in FIGS. 5 and 6, plate 30 contains a plurality of radially disposed teeth 31, separated by spaces of equal width.
Iournalled upon shaft 28 for rotational and axial movement is a lock housing 32, best seen in FIGS. 7 and 8, which, on one of its faces, has teeth 33 of size and position for fitting in the spaces between the teeth 31. Projecting from the other face of housing 32 is a ange 34 which is interrupted to form diametrically opposed sockets 35.
As will be seen best in FIG. 12, a generally circular keeper 36 is fitted within the flange 34 and has radially extending ears 37 which project into sockets 35. Projecting inwardly of the keeper are cam surfaces which terminate in radially disposed shoulders 38 that lie on the median lines of ears 37.
Disposed within keeper 36 is a cam lock 40 that is fitted on shaft 28 and keyed against rotation thereon by engagement with opposed flat faces on the shaft. Projecting outwardly from the cam lock 40 are cams 41, shown to be three in number, each of which terminates in a radially disposed shoulder 42. It will be apparent that during clockwise rotation of the shaft cam lock 40 will reciprocate keeper 36 and that counterclockwise rotation will engage the radial shoulders on the cam lock with the shoulders on the keeper.
The cavity in the lock housing 32 in which the cam lock 40 and the keeper 36 are disposed is closed by a rectangular plate 43 which engages opposite walls of the housing 20 and contains a perforation through which shaft 28 projects. A spring 44 encircles shaft 28 and abuts against plate 43 and bushing 27A and is tensioned to urge the lock housing to the left, as seen in FIG. ll, with the teeth 33 projecting into the spaces between teeth 31 on the lock plate. The cavity in the lock housing is preferably filled with a suitable lubricant.
Mounted upon shaft 28 between bushings 27 and 27A is a cable drum 4S best seen in FIGS. 9, l0 and l1. This drum consists of a cylindrical portion 46 at one end of which is a collar 47 which contains a diagonal slot 48. The hub 49 contains a plurality of end opening U-shaped slots, six in number in the example shown. Also mounted upon the shaft is a collar 50 which is identical in construction with the collar portion 47 of drum 45. A spacer 51 abuts against bushing 27 and the hub of collar 50 to keep that collar abutted against the drum and the drum hub against the bushing 27A.
Mounted upon shaft 28 is a cylindrical sleeve 52 which projects through the openings in housing 20 and lock plate 30 into engagement with lock housing 32. Sleeve 52 contains diametrically opposed diagonally disposed slots 54. A pin 53 disposed in a perforation in shaft 28 extends into slots 54 to key sleeve onto the shaft while permitting limited rotary and axial movement with respect to the shaft. Sleeve 52 is partially disposed within the hub of a crank 55 and is secured therein by a drive pin 56.
Normally spring 44 forces the lock housing 32 and the crank 55 outwardly of the housing 20, positioning the pin 53 in the end of slot 54 in which it is shown in FIG. 11. Clockwise rotation of the crank rotates the shaft and cam lock 40 moves the keeper 36 -back and forth laterally when the housing is in the position shown in FIG. 12. Counterclockwise rotation of crank 55 cams sleeve 52 inwardly of the housing 20 as pin 53 moves from the end of slot 54, in which it is shown in FIG. 11, to the opposite end of the slot. Inward movement of sleeve 52 pushes lock housing 32 inwardly compressing spring 44. This movement of housing 32 disengages teeth 33 from teeth 31 on lock plate 30, freeing the housing for rotation. Counterclockwise rotation of the shaft 28 drives cam lock 40 which drives keeper 36 through engagement 0f a radial shoulder 42 on the cam lock with one of the shoulders 38 on the keeper. Rotation of the keeper 36 drives housing 32 through engagement of ears 37 with the edges of slots 35. When the force rotating crank 55 counterclockwise is removed, spring 44 restores the lock housing and crank to the position shown in FIG. 1l.
Preferably bushings 27 and 27A, lock plate 30, lock housing 32, plate 43, cable drum 45, collar 50 and sleeve 52, are composed of oil impregnated sintered steel, commercially known as Oilite, although the use of other materials therein is contemplated.
Fixed to the underside of base plate 25, by suitable means such as bolts, is a mounting plate 58 to which a rigid tube 59 is attached in convenient manner such as by welding. Tube 59 extends downwardly and terminates in a pressure plate 60, FIGS. 2 and 3, which is attached thereto in convenient manner such as by welding. Adjacent its lower end, tube 59 contains a slot 61 in which a sheave 62 is journalled.
As will be seen best in FIGS. 2, 3 and 4, a cable retainer 63 attached to one sidewall of post 15, in convenient manner such as by screws, contains a formed portion 64 which is shaped to embrace a ball on a cable to attach the cable to the post. Portion 65 of the retainer extends across the post and is fastened to the opposite wall thereof. Portion 65 extends downwardly and forms an up stop, as will presently appear. Section 66 of a cable extends downwardly from retainer 63, around sheave 62, thence upwardly alongside tube 59 to drum 45, thence through slot 48 into the collar 47. A ball on the end of the cable attaches it to the drum. The drum is then rotated clockwise to take up slack in the cable and then secured on the shaft by a drive pin 67 that extends through slots in the hub 49 and a perforation in the shaft 28. A section 68 of the cable extends upwardly from retainer 63, thence through the slot in collar 50 to which collar it is secured by a ball on the end of the cable. Collar 50 is rotated counterclockwise to take up slack in the cable and is then secured on the shaft by a drive pin 69 that extends through slots in the hub of the collar and a perforation in shaft 28.
Positioned in the lower 4post 15 is a U-shaped spring cage 70, the closed end of which engages the presser plate 60. A pair of constant force springs 71 are disposed between the side arms of the spring cage and wound around arbors 72 which are journalled in the cage by pins 73 which project through perforations in the Side arms and into counter bores in the arbor. The heads of pins 73 engage the inner surface of the side walls of post 15 to guide the spring cage during movement within the post.
The ends 71A of the constant force springs 71 are unwound and extended upwardly along the side Wall of the post 15 and are bolted to a hook 74 that is hooked over the top edge of an end wall of the post to attach the springs to the post. Constant force springs commercially available under the name NEGATOR have been found to be satisfactory for this purpose. These springs when unwound tend to rewind themselves and, hence, with the arrangement shown, the spring cage 70 exerts a constant force upwardly through the presser plate 60 and tube 59 to the movable portion of the table. This force is not suficient to overcome the pull of gravity on the upper portion of the table, but rather, falls short of the required force by a small amount, say about three pounds.
RAISING THE TABLE When it is desired to elevate the overbed portion of the table, crank 55 is operated in a clockwise direction. Pin 53 in engagement with the end 0f slot 54, as shown in FIG. 1l, keys the crank to the Shaft and drum 45 iS rotated. Rotation of drum 45 in a clockwise direction winds the cable section 66 on the drum, thereby shortening the length of the section of the Cable 66 between the retainer 63 and the sheave 62. This pull of the cable augments the force of springs 71, thereby raising the table upon the post 15. Clockwise rotation of the drum 45 unwinds section 68 of the cable therefrom to lengthen the same between the point of attachment 63 and the drum.
During vertical movements of the post 17 with respect to the post 15, post 17 is guided by a pair of rollers 76 journalled at the top of the post 15, which rollers engage the inner surfaces of opposed walls of the post 17. A roller 77 journalled in a suitable bracket that is fixed at the bottom of the post 17 is disposed in the channel 16 in the post 15 engaging the web of the channel to aid in guiding the upper post. A plurality of low friction plastic buttons 79, preferably nylon, carried on the walls of one of the posts engage the adjacent walls of the other post to aid in guiding post 17. The spring cage 70 is guided by a roller 78 that engages the web of channel 16 by the engagement of ends 71A of springs 71 with the end wall of post 15 and by the engagement of heads of pins 73 with the sidewalls of post 15.
Upward movement of the table can continue until the closed end of spring cage 70 engages the bottom edge of up stop 65.
THE LOCK MECHANISM As will be seen best in FIG. l2, during rotation of the shaft clockwise, cams 41 on the Cam lock 40 engage the bosses on the keeper 36 alternatively and impart a reciprocating motion to the keeper so long as the clockwise rotation of the shaft continues. When the operating force on the crank is removed, the weight of the overbed portion of the table will cause slight counterclockwise rotation of the shaft, this rotation continuing until one of the shoulders 42 on the cam lock engages a shoulder 38 on the keeper 36. This engagement prevents further counterclockwise rotation Of the shaft since the ears 37 engaged in the slots 35 prevent rotation of the keeper with respect to the housing 32 and engagement of the teeth 33 with teeth 31 prevent rotation of the housing. Thus, there is provided a positive lock that prevents downward movement of the overbed portion of the table, except through an operation of the crank. Although the lock mechanism definitely prevents lowering the table, it does not interfere with the raising of the same. Should a slight force acting upwardly on the table be sucient to augment the force of springs 71, the table will move upwardly. This upward movement of the table causes cable section 68 to rotate the shaft and drum clockwise and cam lock 40 imparts reciprocating motion to the keeper, the same as when the crank is operated clockwise.
LOWERING THE TABLE When it is desired to lower the table, crank 55 is operated counterclockwise, the initial rotation moving the pin 53 from the position shown in FIG. 11 through the slot 54 to the opposite end of the slot. This movement cams the collar 52 and crank 55 inwardly thereby moving the lock housing 32 inwardly against the tension of spring 44. Inward movement of housing 32 disengages teeth 33 from teeth 31 freeing the shaft 28 for counterclockwise rotation. This counterclockwise rotation winds the portion 68 of the cable onto the drum 45 and unwinds portion 66 of the cable therefrom. Through this o-peration, the table is pulled downwardly against the force of springs 71. As soon as the desired position of the talble is reached and force removed from the crank, spring 44 moves the housing 32 to re-engage teeth 33 with teeth 31 and further downward movement of the table is thus prevented.
As will be seen best in FIGS. 3 and 13, the table frame 18 consists of a hollow rectangular frame 21, fixed to housing 20 in convenient manner such as by welding. Frame 21 is preferably formed of rectangular tubing. Reinforcing bars 22, preferably angles, are welded to the housing and frame. Fixed across the post end of frame 21 is a rail 23 that extends across the top of housing 20,
p FIGS. 3 and 13, from side to side of the frame. A second rail 24 is xed at the end of the frame remote the post.
Fitted in the table frame 18 is a tray 80, preferably composed of a suitable plastic, which tray has a planar upper portion 81 that rests upon frame 21 to support the tray on the frame. Portion 81 contains slots 82 through which rails 23 and 24 project when the tray is positioned on the frame. The outer edge of the tray contains a depending flange 83 disposed alongside the frame 21 to conceal the same. The tray is secured on the frame 21 by stops 84, FIG. 14, preferably com-posed of plastic, through which are extended screws, not shown, that project through perforatiions 85 in the tray and into tapped holes 86 in the frame. In addition to securing the tray on the frame, stops 84 limit lateral movement of the top 19, as will presently appear.
The portion of the tray within the frame 21 is depressed to form a shallow pocket 87 which merges into a deeper pocket 88 adjacent the post end of the frame. Rising out of the bottom of the tray are bosses 89 and 89 located on the longitudinal median line of the tray. The bosses are preferably rectangular in shape and terminate in at tops that are disposed in a common horizontal plane.
Fixed to the tops of bosses 89 and 89 in convenient manner such as by bolts is the center section 90 of a hinge. One movable arm 91 is pivotally connected to section 90 by a pin 92, and to the frame 93 of a mirror 94 in convenient manner such as by screws. A second movable arm 95 is pivotally connected to section 90 by a pin 96 and to the frame 97 of a mirror 98. A spring 99 surrounds each of the pins 92 and 96 and has an end engaging the underside of the section 90 and an end engaging the edge of the associated mirror frame. The springs 99 are tensioned to move the mirrors from a horizontal to an inclined position. Frames 93 and 97 are composed of plastic and are devoid of sharp corners that could injure a patient.
Upstanding from the portion 81, at the ends of the tray, are bosses 100 which are located upon the longitudinal median line of the tray. Each boss 100 contains an indentation or dimple in its upper surface` The table top 19 may be composed of wood, chipboard or other suitable material surfaced with a stain-resistant material such as, for exam-ple, Formica. The top is held on the frame by 1brackets 101 of known design located on the longitudinal median line of the top. As shown best in FIG. 3, the brackets 101 are metal clips which carry metal spheres that engage beneath the heads of rails 23 and 24 and provide for moving the top laterally on the frame. This lateral movement is limited by engagement of the brackets 101 with the stops 84 to prevent unwanted removal of the top from the frame.
Located on the underside of the top 19 and on the longitudinal median line thereof are spring-pressed detents 102. which engage in the dimples in bosses 100 when the top is centered on the frame. With the top so centered, springs 99 hold the mirror frames 93 and 96 in engagement with the underside of the top, as shown in FIG. 16. As the top is moved laterally from the full line to the dotted line position in this figure, when the trailing edge of the top moves out of engagement with the mirror frame 93, spring 99 rotates the mirror clockwise around pin 92. By governing the position in which lateral movement of the top is stopped, the angle at which the mirror is placed can be fixed at the convenience of the patient. Lateral movement of the top exposes articles in the tray sections 87 and 88, rendering them readily accessible to the patient.
As the top 19 is Imoved back to its normal position, the leading edge of the top engage the frame 93 and further movement cams the mirror back into the position in which it is shown in FIG. 16. Movement of the top from center to the left, as seen in FIG. 16, permits the associated spring to move mirror 98 upwardly in the same manner.
To insure that the overbed table will harmonize with the decor of hospital rooms in which it will be used, the exposed metal parts are painted with a neutral color such as light grey, for example. To enhance the appearance of the table, the channel 16 in the post 15 is covered with a decorative channel shaped member 105, FlGS. 1 and 4, which fits over the iianges of channel 16 and is secured to the web of that channel in convenient manner such as Iby screws. Member 105 extends upwardly from base member 12 to a point above the lower edge of post 17 when the ta'ble is elevated to its uppermost position.
To prevent chipping the paint on post 17, should the post be moved into contact with a bed, a channel shaped member 106, FIGS. l and 4, is fixed upon the end of the post that is adjacent the channel 16 by a suitable adhesive. Member 106 extends from top to bottom of post 17. Preferably members 105 and 106 are composed of stainless steel, although the use of other materials therein is contemplated.
The overbed table of the present invention combines the advantages of spring assisted tables with the advantages of crank operated tables. Since the crank is only required to apply a small force augmenting the force of the springs, gearing down of the crank is not necessary and only a relatively few turns of the crank are all that are required to move the table from its lowermost to its uppermost position. The positive action of the lock mechanism prevents unwanted downward movement even though the table be overloaded.
From the foregoing, it will be apparent that we have provided an overbed table of rugged construction capable of performing in a satisfactory manner with a minimum of maintenance. The table is completely safe to use under all conditions likely to be encountered, since the overhanging portion of the table is free to be moved upwardly by an application of a small force thereon. At no time can the overhanging portion of the table be lowered, except through an operation of the crank. The table is of pleasing appearance that fits well into the decor of the room in which it is to be used.
Having thus complied with the statutes and shown and described a preferred embodiment of our invention, what we consider new and desire to have protected by Letters Patent is pointed out in the appended claims.
What we claim is:
1. An overbed table comprising:
( a) an upper section containing a post from the upper end of which a tray supporting frame extends laterally and is covered by a table top, a oor supported lower section containing an upstanding post telescoped into said upper section post said upper section being movable vertically with respect to said lower section;
(b) a constant force spring means including a cage fixed with respect to the upper section and movably disposed in the post of the lower section, a pair of constant force springs journaled in said cage, each having an end attached to the lower section, said springs tending to elevate the upper section;
(c) cable means operable to augment the force of said spring means to elevate the upper section and to lower that section against the force of said spring means',
(d) and lock means in said upper section -for controlling said cable means to prevent only lowering the upper section.
2. An overbed table as specified in claim 1 in which the cage is positioned by a rigid member that is fixed at the upper end of the upper section post and is abutted against the cage and in which a sheave is journaled in said member adjacent the abutting end thereof.
3. An overbed table as specified in claim 2 in which the cable means includes a drum fixed upon a shaft journaled at the top of the upper section post; around said drum a first section of the cable is wound clockwise and extended therefrom around said sheave to a cable retainer fixed at the upper end of the lower section post, and a second section of said cable is extended from said retainer to said drum around which it is Wound counterclockwise.
4. An overbed table as specified in claim 3 in which the cable retainer includes an up stop portion adapted to engage the spring cage to limit upward movement of the upper section.
5. An overbed table as specified in claim 3 in which application of force of said upper section suicient to augment said spring force moves the section upwardly and rotates the shaft clockwise by unwinding the cable section that is wound counterclockwise on said drum.
6. An overbed table as specified in claim 3 in which the lock means includes a lock plate fixed against rotation and having teeth projecting `from one of its faces, a lock housing encircling the shaft and having teeth registered with the lock plate teeth, a keeper within said housing fixed against rotation therein but capable of reciprocating movements, a cam lock on said shaft fixed against rotation but capable of axial movement thereon and having a plurality of shoulders, said keeper being reciprocated by clockwise rotation of said shaft and cam lock and having shoulders one of which is engaged by a shoulder on the cam lock by slight counterclockwise rotation to prevent further counterclockwise rotation of the shaft.
7. An overbed table as specified in claim 6 in which a crank has a hub in which a sleeve is lixed, said sleeve rotatably and slidably engaging said shaft and being keyed thereto by a pin that projects through the shaft into diagonally disposed slots in the sleeve, counterclockwise rotation of the crank moving the crank inwardly as said pin moves to one end of said slots, said sleeve moving said lock housing teeth out of registration with said lock plate teeth to free the shaft for counterelockwise rotation, a shaft encircling spring moving said lock housing teeth back into registration with said lock plate teeth and moving said crank outwardly when operating force is removed from the crank.
8. An overbed table as specified in claim 1 in which a pair of mirrors are supported on said tray by springpressed hinge means and maintained in horizontal position through engagement with said top in contents-concealing position, each mirror being moved by said hinge means out of horizontal into upstanding position as the top is moved laterally out of engagement with that mirror.
9. An overbed table as specied in claim 8 in which the spring-pressed hinge means includes a central element Xed on the tray, a pair of movable members pivotally attached to said element, one on each side thereof and attached to the frame of the associated mirror, and a pair of springs, one individual to each member.
References Cited UNITED STATES PATENTS 4/1944 Hillenbrand 108-50 X 2/1953 Berner 10S-146 X 8/1954 Woller 10S-146 11/1954 Morrow 10S-136 1/1956 Berner et al 108-50 X 6/1956 Smith 10S-147 9/ 1959 Sehlackman et al- 108--26 X 11/1964 Hinden et al 10S-150 X 12/ 1964 Armstrong 108-147 7/1965 Linder et a1 108-146 6/ 1965 La Vigne 108-136 U.S. Cl. X.R.