US2038410A - Wall bed actuating mechanism - Google Patents

Description

E. H. BRIDENBAUGH WALL BED ACTUA'IING MECHANISM April 21, 19%.

.Filed A ril 28, 1954 3 Sheets-Sheet l zmwm A ril 21, 1936. E. H. BRIDENBAUGH v WALL BED ACTUATING MECHANISM Filed April 28, 1934 5 Sheets-Sheet 2 fmjenfor EYmew/iBrienau h.

, 1936- E. H. BRIDENBAUGH WALL BED ACTUATING MECHANI SM April 21 3 Sheets-Sheet 3 Filed April 28, 1934 In z/enfoz Elmer/1B1) e 3 d) Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE WALL BED ACTUATING MECHANISM Application April 28, 1934, Serial No. 722,940

14 Claims.

This invention relates to beds of a type arranged for concealed. storage when not required for use and for ready extension from such storage to usable position when desired, and has as an ,5 object to provide an improved construction of and arrangement of operative elements in such a bed.

A further object of the invention is to provide an improved bed construction foldable into a wall v recess or closet.

A further object of the invention is to provide an improved foldable, wall-type bed arranged for storage cooperation with a relatively small recess or closet.

A further object of the invention is to provide an improved bed construction foldable into vertically-disposed frame position above and extensible into horizontally-disposed frame position from a base frame fixed within a wall recess or closet.

A further object of the invention is to provide an improved foldable, wall-type bed arranged for either manual or power actuation.

A further object of the invention is to provide an improved mounting for a foldable, wall-type bed.

A further object of the invention is to provide an improved combination of a foldable, wall-type bed with supporting means operable to effect extension or retraction of said bed.

A further object of the invention is to provide improved supporting means for a foldable, walltype bed operable to transmit limited shaft rotation to effect complete extension or retraction of said bed.

A further object of the invention is to provide improved means for pivotally supporting a foldable, wall-type bed, said means being operable through limited shaft rotation to rotate said bed 40 on its pivotal mounting and subsequently impart arcuate motion to said pivotal mounting.

A further object of the invention is to provide improved mounting and actuating means for a 5 foldable, wall-type bed, which means operate to positively limit travel of said bed when in either extreme of its range of travel.

A further object of the invention is to provide improved means in a mounting for a foldable, wall-type bed automatically engageable and releasable to positively latch said bed against accidental displacement from its folded position.

A further object of the invention is to provide improved means automatically operable to eifectively counterbalance the variable moment produced by arcuate motion of a foldable, wall-type bed relative to its mounting.

A further object of the invention is to provide improved means automatically operable for efiective control of hinged head and foot frame sections in a foldable, wall-type bed.

A further object of the invention is to provide an improved, operative, foldable, wall-type bed assembly that is positive and efficient in operation, arranged for either manual or power actuation, susceptible of ready operative combination with power units or appliances of various types, simple of installation in a minimum of space, and substantially unlimited in its adaptability to specificuses and installations.

For an example of power actuating mechanism which is readily combinable with the present invention, I refer tomy application filed contemporaneously herewith for improvements in Hydraulic actuating mechanism.

My invention consists in. the construction, arrangement and combination of elements hereinafter described, pointed out in my claims and illustrated by the accompanying drawings, in which: 1

Figure 1 is a side elevation of a power-equipped bed installation embodying the principles of the invention, portions of the structure being broken away to conserve space.

Figure 2 is an elevation similar to Figure 1 with the power unit removed and certain elements broken away to conserve space and to better illustrate otherwise concealed construction.

Figure 3 is an elevation similar to Figure 2 illustrating the elements of the latter figure in folded or retracted relation.

I Figure 4 is a vertical transverse section taken ,on the indicated line 4-4 of Figure 2.

Figure 5 is a fragmentary, detail section taken on the indicated line 5-5 of Figure 2.

Figure 6 is a plan view of the base frame and counterbalancing mechanism employed in the invention, bed supporting and actuating elements connectible with said base frame being omitted.

Figure 7 is a detail section taken on the indicated line 1-1 of Figure 6.

In the construction of the improved bed as shown, the numeral l0 designates a bed frame side rail, two of which are employed in spaced, parallel relation, one end of said rail being secured in fixed relation with and extending perpendicularly from a head frame portion I I and the other end of said rail being secured in like manner to a .foot frame portion I 2, the two frame portions and rails thus cooperating to form a complete 2 A and rigidly interconnected bed frame. The rails I are preferably formed with midportions l0 offset beneath the normal top plane of the bed frame, and said rails carry and suitably support a spring assembly I3 which preferably includes longer spring elements arranged to receive and support the major weight of a bed occupant and shorter spring elements adjacent end portions of the assembly.

The head frame I I is provided with an extension I I' hinged to its upper margin and arranged a to fold toward and in overlying relation with a portion of the spring assembly I3, and the foot frame I2 is provided with an extension I2 hinged to its lower margin and arranged to fold toward and in underlying relation with said spring assembly, the rigid portions of said head and foot frames having substantially equal extension on the spring side of and relative to the rails I0 and very little extension on the other side of their attachment with said rails, the extension I2 having a length suflicient, when alined with the fixed portion I2, to position the spring assembly I3 at conventional elevation above a supporting surface, and the extension II having such projection above the spring assembly, when alined with the fixed portion I I, as may be desired in a given design or installation.

Fixed to the rails I0 adjacent and spaced somewhat from the head frame II, frame elements, such as angle blocks I4, project laterally from opposite sides of said rails, said frame elements being alined transversely of the bed frame and being provided with vertically-depending web portions to which are rigidly secured identical, eccentric gear quadrants I arranged with their toothed margins directed toward the head frame I I. Registering holes are formed through the vertical webs of the elements I4 and through the gear quadrants I5 to receive a shaft I6, thus positioned transversely of the head end of the bed frame beneath the rails I0.

A suitable base frame I'I including spaced, parallel, upstanding flanges or ribs I8 is fabricated, preferably in skeleton form, of suitable elements, and is arranged with the flanges I3 rigidly interconnected in a spacing somewhat in excess of that separating the rails I0, said frame I! being adapted to be suitably positioned on and secured to the floor of a wall recess, closet, or the like, wherein the bed assembly is to be folded for storage.

Brackets I9 are provided on and extend laterally from forward portions of the flanges I8 to support pins 20 whereon levers 2| are pivoted for actuation through vertical arcs, said levers 2I being formed with yoked upper portions 2I' between the arms whereof are received the assemblies-of elements I4, I5, the shaft I6 engaging through holes in said yoke arms to pivotally link the bed frame with the base I'I.

Disposed longitudinally of the frame I! in spaced parallelism with the shaft I6 and. journaled for rotation in suitable bearings 25 carried in fixed relation by the flanges I8, an actuating shaft 26 is mounted just above the upper margins of said flanges I8, said shaft being provided with identical gear quadrants 21 fixed on each end thereof coplanar with the corresponding gear elements I5, in spaced relation with the latter and with their toothed margins directed, when the bed is in open position, toward said elements I5.

Pivotally mounted on fixed pins 28 extending oppositely from the flanges I8 adjacent andbeneath and forwardly out of vertical alinement with end portions of the shaft 26, pairs of spaced levers rise on opposite sides of each of the gear quadrants 21, the inner lever of each pair, indicated at 29, being curved to pass about and over the shaft 26, rearwardly thereof, and the outer lever of each pair, indicated at 30, being formed with a large central web apertured for free passage of said shaft therethrough. The upper ends of the levers 29 and 36 are formed with registering holes wherein is mounted a pin 3| positioned, when the bed is in open position, in the same horizontal plane with and spaced rearwardly of the shaft I6, said pins 3I and shaft I6 being pivotally interconnected by means of links 32 to preserve the spacing therebetween.

A gear unit 33 is mounted on each pin 3| for free rotation relative thereto, each said unit comprising an eccentric marginal portion engaged by and adapted to mesh with the corresponding gear element I5 and a concentric marginal portion engaged by and adapted to mesh with the corresponding gear quadrant 21, the junction between said marginal portions being formed as a notched offset 34.

With the arrangement thus far described, it is obvious that, referring to Figure 2, rotation of the shaft 26 in a counterclockwise direction carries the gear quadrant 21 on each end of the said shaft in the corresponding direction, which motion acts to rotate each unit 33 about its pin 3I in the opposite direction, thereby actuating the gear elements I5 to rotate the bed frame assembly about its pivotal mounting on the shaft I6 through a vertical arc upwardly and into folded relation within the recess or closet containing the base frame H.

To move the shaft I6 rearwardly into the recess or closet subsequently to the pivotal motion f the bed frame about said shaft, and to provide means automatically operable to latch the movable assembly against accidental displacement from folded position, the web portion of each lever 36 is formed with an arcuate slot 35 concentric with the shaft 26 and extending ninety degrees from the longitudinal axis of said lever in a rearward and downward direction and slightly less than ninety degrees in a forward and downward direction from said axis, and each gear quadrant 2'! is provided with a pair of spaced rollers 36, mounted for free rotation on spindles projecting perpendicularly from the outer face of said quadrant in position to engage within and move through portions of the corresponding arcuate slot 35, said rollers being spaced ninety degrees apart and so arranged as to position the forward of said rollers in end engagement with the forward portion of its slot 35 when the bed is in open position, the rearward of said rollers consequently having less than ninety degrees to travel to effect end contact with the rearward portion of said slot. With the arrangement just above described, when the bed assembly is actuated and moved into folded position, the rollers 36 travel freely through their respective portions of the slot 25 until the bed frame has traveled almost ninety degrees of arc, at which time contact is effected between the rearward roller and the corresponding end of the slot 35, which contact acts, through continued rotation of the shaft 26, to move the paired, linked levers 29 and 36 about their common pivot, swinging the upper ends of said levers and the pin 3| supported thereby rearwardly of the recess or closet, and, by virtue of the links 32, drawing the shaft I6 and all elements mounted thereon, including the bed frame assembly, rear- 'wardly into said recess or closet.

The rearward-endof the slot 35 has an arcuate notch offset toward the shaft 26 to receive the "rearward of the rollers 36 when the lever carrying said slot is moved eccentrically relative tosa-id shaft and'rollers,'the engagement of said roller within said notch acting as a latch to securelyhold the assembly in folded relation save when reverse motion is imparted to the shaft '26.

To positively limit arcuate travel of the linked levers 2| and 30, thereby limiting .movement of the bed frameassembly relative to the base frame I! and wall recess or closet, a link '22 is pivotally secured at one end to a rearward portion ofeach ba-se'fiange 1-8 and rises forwardly from such connection to overlapping relation of its free end with that portion of the corresponding lever 30 above the slotted web portion of the latter.

The free end of the link 22 is formed with an L-shaped slot 23 disposed with its longer member approaching the horizontal and its shorter member directed upwardly toward the pin 3|, which slot slidingly embraces a pin or roller element 24 projecting in fixed relation with and laterally from the lever 30, so that end engagement of the slot 23 with said element 24 acts to positively limit arcuate travel of the lever 30 in either direction, and, through the link 32, correspondingly limit arcuate travel of the lever 2|,

the longer member of said slot 23 being so disposed and having such length as to position said lever 2| somewhat forwardly of the vertical when the bed frame is in open position and somewhat rearwardly of the vertical when the said frame is in folded position, the weight of the bed frame elements thereby acting to retain said lever 2| against accidental displacement from either of its extreme positions, intentional displacement of said lever requiring an intial upward impulse applied to the weight supported thereby.

The shorter member of the slot 23 acts as a latch to hold the bed frame actuating elements in open or extended frame position, since upon engagement of the element 24 with the forward end of the slot 23, the shorter member of said slot is positioned in potential embracing relation with and above said element 24 and automatically moves into such embracing relation therewith under the influence -of gravity acting on the .link 22 to engage-said element 24 and prevent arcuate travel of the lever 30 in either direction, as clearly illustrated in Figure 2.

To release the latching engagement between the element 24 and link 22 for bed-folding actuation of the operating elements, the link 22 must be moved upwardly about its fulcrum to bring the element 24into the longer member of the slot 23, which may be automatically accomplished by means of a depending extension on the free end of said link 22 terminating in a beveled extremity positioned in the path of the rollers 36, the forward of said rollers engaging said beveled extremity as said roller is moved rearwardly of the arcuate slot through theagency of the shaft 26 and lifting the free .end of said link 22 for release of the latching effect on the element 24, thereby permitting subsequent actuation of the levers 30 and 2! in the manner previously described.

A further limitation of rotation of the bed frame in a folding direction about the shaft I6 is provided by the offset notch 34 of the unit 33, which offset engages against the foremost of the rollers 36 to prevent further relative travel between the meshing elements 2-1 and 33 when the bed frame has reached its vertical position.

It is of course obvious that rotation of the shaft 26 in a clockwise direction will act to reverse the cycle above described and extend the bed assembly from folded position within its recessor closet to extended usable position.

To automatically position the hinged head and foot frame portions II and I2 and to maintain said portions in parallel, substantially vertical relation irrespective of the relative position of the other bed frame elements, a drag link 31 is positioned adjacent and beneath each of the rails it and is mounted for free reciprocation parallel with said rails in a slide bearing 38 carried by an adjacent rail portion 10'. The forward end of each link 31 pivotally supports one end of a relaitively flexible spring link 39, the forward end of which latter pivotally engages .a rigid element -of the foot frame portion l2. The rearward end of the link 31 is pivotally engaged by one end of a relatively flexible lever '40, which latter rises past operative engagement with a fulcrum 4| fixed to the rigid head frame portion I l to pivotal engagement of its other end with a short link 42 behind .said head frame, said short link 42 being .pivotally connected with a rigid element of the head frame portion l An operating link 43 pivota-lly connects the midportion of the drag link 31 with a :bracket 44 extending laterally from the lever 2.! below the pivotal connection of said lever with the shaft 16 and acts, as the bed assembly is moved to folded position, to move the drag .link rearwardly of its rail l0 and fold, through the spring link .39 and lever 40, the hinged frame portions l I and 12' toward the bed frame proper .and into the relative positions shown in Figure 3, unfolding motion .of the bed assembly acting through. the same agencies to extend the hinged frame portions :into .alinement with their respective cooperating fixed frame portions.

Since arcuate travel .of the bed frame assembly produces .a variable moment which reaches its maximum as the said assembly reaches its horizontal position, it is desirable to provide .means effective to maintain the torque load on the shaft 26 reasonably constant during actuation of said assembly, one such means being illustrated in operative combination with the bed assembly and hereinafter described. As best shown in Figure 6, fixed 'pins '45 rise in parallel, spaced relation from rigid elements of the base frame I1 adjacent each end of the latter and support bell-crank assemblies comprising each a longer arm 46 and a shorter arm 4! for actuation of said arms through parallel horizontal arcs. The bell-crank assemblies :are arranged in opposition on their respective pins 45 with their longer arms 46 diverging forwardly of the frame I! to pivotally support alined plunger elements 48 slidably engaging within opposite ends of .a tubular housing '49, which latter is thus positioned and supported independently of and for motion relative to the base frame IT. The plunger elements 48 are urged apart by means of expansive coil spring elements 50 loosely mounted within the housing 49 and each bearing at its inner end against a stop plate 5| freely slidable within said housing, said stop plates being adjustably interconnected by means of a coupling bolt 52 having oppositely threaded ends operative engaging axially through said plates, an angular boss on the bolt 52 between the engaged plates 5| providing for tool engagement of said bolt and consequentadjustment of the spring pressure exerted formed in the housing 49 to permit of such adjustment. Travel of the plunger elements 48 outwardly of the housing 49 is limited by means of adjustable stops 53 carried in the free ends of radial arms 54 extending from the bell-crank assemblies in position for end engagement of said stops with a fixed link 55 interconnecting the pins 45.

Flexible connections, such as cables or chains 53, are fixed at one end each to outer extremities of the bell-crank arms 41 and extend therefrom forwardly of the base frame 11, under and partially about pulleys 51 fixed adjacent outer, forward corners of said base frame, and upwardly from said pulleys to attachment of their other ends in fixed relation with frame elements rigidly secured to the rails Ill rearwardly of the shaft It, the point of such attachment being in substantially the same horizontal plane as, and rearwardly of, the shaft I6 when the bed assembly is in extended position.

It is readily apparent that as the bed assembly is moved from folded to open position, rotation of the bed frame about the shaft l6 exerts tension on the flexible connections 56 which acts to rotate the bell-crank arms 41 forwardly of the frame H, such rotation moving the arms 46 inwardly to compression of the spring elements 50 as the bed frame is lowered, such compression being progressive and proportioned to the mo-. ment produced by the descending bed frame so as to substantially counter-balance said moment and leave a substantially uniform torque load on the shaft 26. The spring elements 50 remain under compression so long as the bed is extended in open position and act to aid return of the bed assembly to its folded position, the force exerted by said spring elements decreasing as the arms 46 move outwardly relative to the housing 49.

One end of the shaft 26 is preferably extended beyond th bed actuating elements and is formed with an angular section for convenient connection with manual or power means whereby rotation may be imparted to said shaft, it being immaterial in the instant invention what shaft actuating means may be employed, one such means in the form of an electrically-driven, hydraulic transmission unit being illustrated at 58 in Figure 1 in operative relation withthe shaft 26 and anchored by means of an apertured lug 59 fixedly engaging a pin 3i) rising from the base frame ll.

While the bed assembly is preferably arranged for operation through actuation of the shaft 26, it is obvious that force may be manually applied directly to the bed frame to effectively move the latter between its extended and folded positions, the counterbalancing effect of the arrangement provided for that purpose minimizing the amount of force required for effective actuation of the assembly.

At 62 in Figure 4 is indicated in dotted lines a conventional hand lever arranged for operative association with an angularly sectioned end of the shaft 26, which lever may be employed in place of the power unit 58 for actuation of the bed mechanism or may be utilized in engagement with the opposite end of the shaft 26 to supplement said power unit. With the bed frame suitably counterbalanced, said frame may be actuated between its extreme positions through rotation of the shaft 26 produced by application of manual power to said lever $2, or the said frame may be manually moved between horizontal and vertical positions and the said 1ever'62 employed for extension on the plungers 48, an opening being preferably or retraction of the bed frame axis relative to the closet or recess, the specific manner in which power is applied to the shaft 26 or bed frame assembly in no way altering or modifying the operative relation of the actuating elements previously described.

A shield plate 6| is preferably mounted on outer of the links 32 in covering relation with the gear elements l5 and 33 to prevent catching of bed clothing or operators fingers between said gear elements.

Since many changes, modifications and variations in the specific form, construction and arrangement of the elements shown and described may be had without departing from the spirit of the invention, I wish to be understood as being limited solely by the scope of the appended claims rather than by any details of the illustrative showing and foregoing description.

I claim as my invention 1. In a wall bed, a bed frame pivotally mounted for actuation about a transverse axis, means pivotally supporting said axis for limited arcuate motion thereof, and actuating means engaging said frame and axis and progressively operable to successively rotate said frame about said axis and to vary the position of the latter.

2. In a foldable wall bed having a bed frame pivotally mounted for actuation through a vertical are between open and folded positions and 1 frame actuating means including a rotatable operating element, an actuating element operable by and concentric with said operating element, a lever pivoted eccentrically with and adjacent said operating element and arcuate guide means fixedly carried by said lever in normally concentric relation with said operating element in position to be engaged by and traversed by said actuating element, means automatically operable to latch said bed frame in and against accidental displacement from its folded position, said means comprising an end limit of said arcuate guide means positioned for engagement by said actuating element as said bed frame approaches closed position, which end engagement acts to swing the guide-supporting lever into eccentric relation of said arcuate. guide with said operating element,

and a notch adjacent the end limit of said arcuate guide opening into and offset inwardly of said arcuate guide in position to be moved into latching relation about and over said actuating means during eccentric disposition of said arcuate guide relative to said operating element.

3. A foldable wall bed comprising a bed frame pivotally mounted for actuation through a vertical arc, means engaging said'bed frame operable to rotate the latter relative to' its mounting, and supplemental means engageable for actuation by said first means adjacentone limit of said bed frame actuation and operable to vary the position of said pivotal frame mounting.

4. A foldable Wall bed comprising a pivotally mounted bed frame, means operable to rotate said frame relative to its mounting, and supplemental meansoperable through engagement with said first means adjacent one limit of said frame rotation to vary the position of said frame mounting.

5. A foldable wall bed comprising a pivotally mounted bed frame and bed frame supporting means progressively operable to vary the position .of said pivotal frame mounting and to rotate said frame relative thereto; together with actuating means engaging said supporting means and frame operable toeifect rotation of the latter and vary the frame mounting position adjacent one limit of said frame rotation.

6. In a wall bed, the operative combination with a pivotally mounted bed frame of frame supportingmeans progressively operable to vary the position of said pivotal frame mounting and to rotate said frame relative thereto, and actuating means engaging said supporting means and frame operable to effect rotation of the latter and vary the frame mounting position adjacent one limit of said frame rotation.

7. In a wall bed, a bed frame pivotally mounted for actuation through eccentrically-related arcs and frame supporting means progressively operable to actuate said frame successively through such arcuate operative range; together with actuating means .engaging said supporting means and operable to effect actuation of said frame progressively through the full range of its arcuate travel.

8. In a wall bed, a bed frame pivotally mounted for actuation in an orbit about a transverse axis, means pivotally supporting saidaxis for limited travel thereof in an arcuate orbit, an operating element in eccentric relation with said frame and axis orbits, connections between said operating element and frame operable to transmit actuation of the former to effect rotation of the latter about its axis, and supplemental connections between said operating element and axis operable to effect arcuate travel of the latter adjacent one limit of the bed frame actuation. 9. In a wall bed, a bed frame pivotally mounted for actuation in an orbit about a transverse axis, means pivotally supporting said axis for limited travel thereof in an arcuate orbit, an operating element in eccentric relation with said frame and axis orbits, connections between said operating element and frame operable to transmit actuation of the former to effect rotation of the latter about its axis, and supplemental connections engaging said axis and actuable by said first connections adjacent one limit of the bed frame actuation to effect travel of said axis.

10. In a wall bed a bed frame pivotally mounted for actuation in an orbit about a transverse axis, means pivotally supporting said axis for limited travel thereof in an arcuate orbit, an operating element in eccentric relation with said frame and axis orbits, intermeshing gear elements interconnecting said operating element and frame and. operable to transmit actuation of the former to effect rotation of the latter about its axis, and supplemental connections engaging said axis and actuable by one of said gear elements adjacent one limit of the bed frame actuation to effect travel of said axis.

11. In a wall bed, a bed frame pivotally mounted for actuation in an orbit about a transverse axis, means pivotally supporting said axis for limited travel thereof in an arcuate orbit, an operating element in eccentric relation with said frame and axis orbits, intermeshing gear elements interconnecting said operating element and frame to transmit actuation of theformer to effect rotation of the latter about its axis, and eccentrically-pivoted lever means engaging said axis and actuable by one of said gear elements adjacent one limit of the bed frame actuation to effect travel of said axis.

12. In a wall bed, a bed frame pivotally mounted for actuation in an orbit about a transverse axis, a base frame, means pivotally interconnecting said axis and base frame for limited travel of the former in an arcuate orbit, an operating element rotatably mounted on said base frame in eccentric relation with said bed frame and axis orbits, intermeshing gear elements interconnecting said operating element and bed frame to transmit rotation of the former to effect rotation of the latter about its axis, and eccentrically-pivoted lever means carried by said base frame in engaging relation with said axis and actuable by one of said gear elements adjacent one limit of the bed frame actuation to effect travel of said axis.

13. In a wall bed, a bed frame pivotally mounted for actuation in an orbit about a transverse axis, a base frame, means pivotally interconnecting said axis and base frame for limited travel of the former in an arcuate orbit, an operating element rotatably mounted on said base frame in eccentric relation with said bed frame and axis orbits, intermeshing gear elements interconnecting said operating element and bed frame to transmit rotation of the former to effect rotation of the latter about its axis, lever means pivoted to said baseframe eccentrically with said operating element and rising adjacent the latter to link connection of its upper end with said axis, an arcuate guide carried by said lever means in concentric relation with said operating element, and actuating means in fixed relation with the gear element carried by said operating element engaged within and adapted to traverse said guide means to endcontact therewith adjacent one limit of the bed frame actuation for operation of said lever means to effect travel of said axis.

14. In a wall bed, a bed frame pivotally mountfor actuation in an orbit about a transverse axis, a base frame, lever means pivotally interconnecting said axis and base frame for travel of the former in an arcuate orbit, an operating element rotatably mounted on said base frame in eccentric relation with said bed frame and axis orbits, gear elements in fixed relation with said operating element and bed frame, lever means pivoted to said base frame in eccentric relation with said operating element and rising adjacent the latter to link connection of its upper end with said axis, means on said base frame engaging said latter lever means to limit arcuate travel thereof, a compound gear element rotatably carried by the upper end of said latter means in meshing relation with both gear elements carried by the operating element and bed frame and operable to transmit rotation of the former to effect rotation of the latter about its axis, stop means positively operable to limit relative travel between said gear elements, an arcuate guide fixedly carried by said last named lever means in concentric relation with said operating element, and actuating means in fixed relation with the gear element carried by said operating element engaged within and adapted to traverse said guide means to end contact therewith adjacent one limit of the bed frame actuation for operation of said latter lever means to effect travel of said axis.

ELMER H. BRIDENBAUGH,

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