IL171366A - Safety mechanism for tiltable bed - Google Patents

Description

Safety mechanism for tiltable bed Aminach Bedding & Furniture o" -x e»3i m on?>m n»¾um nj»i> Manufacturing Ltd., The Inventors: REGEV, Itzhak in n*> JANO, Max UN Op)3 C.162909 SAFETY MECHANISM FOR TILT ABLE BED FIELD OF THE INVENTION The present invention relates to safety drive mechanism applicable in tiltable beds (often referred to as adjustable beds), namely a bed comprising at least one mattress segment tiltable/adjustable with respect to the bed's frame by means of an electric motor and an associated gear mechanism (often articulated/integrated with the motor.

BACKGROUND OF THE INVENTION In recent years it becoming common for individuals to use tiltable beds for domestic use and thus a large variety of tiltable beds are available.

One problem with such beds is that at the event of a substantive weight applied on the mattress or bed frame (e.g. by a heavy weighted individual or by an individual positioned at an end of the bed thus applying a large moment) while attempting to tilt the respective bed section, the electric motor may fail and will damage, often causing also severe damage to the gear associated thereto.

Several patents deal with similar difficulties. For example, US Patent Serial No. 4,120,057 to Neumann discloses an electromechanical adjusting device for pivotable head and/or foot parts of a bed frame with a pivot in the form of a rod movable with the pivotable part and extending transversely of the bed frame comprises a reversible rotary electric motor whose rotor shaft extends at right angles to the rod and drives a worm and worm gear and a pinion for driving the rod and itself driven by the worm and worm gear through spring clutch means, the adjusting device being supported by the rod. 01629096\5-01 US Patent Serial No. 4,324,010 to Houlberg et al, discloses a drive unit for adjustable beds, such as hospital beds and the like, of the type which have movable head and foot sections, and/or other adjustment functions, comprises a single, unidirectional, rotary motor, and a drive shaft for each adjustable bed function. A pair of drive wheels are rotatably mounted on each of the drive shafts, and are rotated thereon in opposite directions by the motor. A pair of spring clutches are operably associated with each pair of drive wheels, and alternatively engage or connect selected drive wheels with their associated shafts to rotate the shafts, and thereby adjust the position and/or configuration of the bed.

US Patent 5,640,730 to Godette discloses an adjustable articulated bed having a back support section, a head rest section, an angled lifting lever, and a crank assembly operatively connecting the bed motor to the lifting lever. A slidable pin-and-slot arrangement connects the head end of the lever to the head rest section. As the lever is pivoted it first tilts the head rest section up relative to the (horizontal) back support section to a relative tilt position. Continued pivoting of the lever causes it to engage, lift and pivot the back support section up about the lifting-lever pivot axis. The head rest section, while maintaining the relative tilt position, is pivoted up with it. A polyfoam foundation affixed to the tops of both the back support and head rest sections tends to drag or lift the back support section up as the head rest section is pivoted up. A spring connected between the back support section and the crank assembly is provided to resist this lifting force, but not prevent the back support section from being lifted with the head rest section in its relative tilt position. Should a downward force be exerted at the end of the head rest section when horizontal (which force can be simply the weight of that section), a stop finger pivotal with the head rest section engages generally against the back support section to block downward pivoting of the head rest section. A bumper on a frame cross member provides a resilient stop for the downward travel of the lifting lever resulting from a downward force on or of the head rest section.

It is an object of the present invention to provide a simple and relatively inexpensive safety mechanism for restricting moments and torque forces transferred to a motor of a tiltable bed at the event of weight or moments applied to the bed frame being greater than a predetermined torque. 01629096\5-01 171366/2 SUMMARY OF THE INVENTION According to the present invention here is provided a bed and a safety mechanism therefore, adapted to prevent or minimize the risk of damage of an electric motor used for tilting/elevating a mattress support of the bed upon .applying thereto a downwardly directed force which exceeds a predetermined force. Said downwardly directed force may be a result of a load mounted on the bed (e.g. an individual sitting/laying on the bed) or some mechanical fault preventing the displacement of the mattress frame. Tilting/elevating the mattress frame may be required e.g. to allow access to a linen compartment of the bed extending there-under.

The invention provides a safety mechanism for a tiltable bed, the comprising a bed frame supporting a mattress frame pivotally articulated to the bed frame, and an electric motor pivotally articulated to the bed frame with an extractable piston rod extending from the motor and , wherein, the rod is coupled at a remote end thereof to the safety mechanism comprising a torque-restricting link which in turn is pivotally mounted on a transverse support bar of the mattress frame, and whereby the torque-restricting link is biased by a spring member born to bear a predetermined load.

According to an embodiment of the invention the torque-restricting link is pivotally displaceable between an unloaded position adapted to bear substantially the load of the mattress frame and a mattress mounted thereon, and a loaded position upon applying thereto a load exceeding the predetermined load.

According to another embodiment of the invention a micro-switch is fitted such that when the torque-restricting link reaches its loaded position it engages the micro-switch so as to halt operation of the electric motor.

According to still an embodiment there is further provided an adjusting screw mechanism for pre-loading the spring member.

By one arrangement of the invention, the mattress frame is articulated to the bed frame by a pair of parallelogram mechanisms each fitted at a respective side of the bed and wherein a lower end of each pivotal bar is fixedly secured to the bed frame arid an upper end of each pivotal bar is fixedly secured to the mattress frame via a mattress frame engaging member, wherein the transverse support bar fixedly extends between said opposite mattress frame engaging members. Optionally, one or both of the parallelogram mechanisms are pneumatically supported. 01629096X56-01 By another arrangement the torque-restricting link comprises a tubular section coaxially mounted over the transverse support bar. Optionally, the spring member is a coiled spring with one end thereof fixed to the torque-restricting link, and another leg thereof fixed to the support bar.

The arrangement may be such that one or both of the torque-restricting link and the remote end of the extractable piston rod is formed with at least two engagement fixtures, whereby pivotal coupling thereof may be at two or more discrete positions.

Typically at a substantially flat, horizontal position of the mattress frame the spring member is substantially unloaded. Further, when the mattress frame is at a tilted, elevated position, and is unloaded by an external force overcoming the predetermined force, the torque-restricting link remains at its unloaded position.

The arrangement is such that when the predetermined load is determined so as to bear the load of the mattress frame with a mattress mounted thereon with linen.

According to a modification of the invention, the mattress frame comprises at least two segments tiltable with respect to one another and with respect to the bed frame, wherein each mattress segment is associated respectively with an electric motor pivotally articulated to the bed frame with a extractable piston rod extending from the motor and coupled at a remote end thereof to torque-restricting link which in turn is pivotally mounted on a transverse support bar of the mattress frame, whereby the torque-restricting link is biased by a spring member pre-loaded to bear a predetermined load.

It is appreciated that also at the event where the mattress is only slightly elevated from the bed frame (say several centimeters) and a load is applied thereto (e.g. a person sitting on the bed) when the motor is still, the mattress frame will displace downwardly under the load until it comes to rest on the bed frame, thus minimizing or avoiding load on the tilting parallelogram mechanisms.

According to another aspect of the invention there is provided a bed comprising a bed frame supporting a mattress frame pivotally articulated to the bed frame, and an electric motor pivotally articulated to the bed frame with a extractable piston rod extending from the motor and a safety mechanism coupled at a remote end of said retractable piston comprising a torque-restricting link which in turn is pivotally mounted 01629096\5-01 on a transverse support bar of the mattress frame, whereby the torque-restricting link is biased by a spring member born to bear a predetermined load.

BRIEF DESCRIPTION OF THE DRAWINGS In order to understand the invention and to see how it may be carried out in practice, an embodiment will now be described, by way of a non-limiting example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view, partially cut out, of a bed fitted with a safety mechanism in accordance with the present invention, with a mattress of the bed at its so called open/tilted position, thus exposing a mattress, frame support mechanism thereof; Fig. 2 A illustrates the bed frame and the mattress frame support mechanism with the mattress frame at the substantially horizontal, namely closed position; Fig. 2B is an enlargement of the portion marked II in Fig. 2A; Fig. 3A illustrates the bed of the invention, without the mattress, whereby the mattress frame support mattress is at its open namely tilted position; Fig. 3B is an enlargement of the portion marked III in Figs. 3 A; Fig. 4A illustrates the bed of the present invention, without the mattress, with the mattress frame support member at its open position, though upon applying a moment of force on the mattress in the direct of arrow F; and Fig. 4B is an enlargement of the portion marked IV in Fig. 4A.

DETAILED DESCRIPTION OF A SPECIFIC EMBODIMENT Referring first to Fig. 1 there is illustrated a bed in accordance with the present invention, generally designated 10 said bed being a so called tiltable bed fitted with a bed frame 14, which in the present example is in the form of a rectangle giving rise to a linen compartment 16.

Pivotally articulated to the bed frame 14 there is a mattress frame 18 bearing a mattress 20. The mattress frame 18 is pivotally articulated to the bed frame by a mattress frame support mechanism generally designated 24 comprising a pair of parallelogram mechanisms 26, each comprising a pair of pivotable bars 30 and 32 pivotable at their lower ends to a bed frame support bar 34 and at their upper end to a 01629096\5-01 - 6 - 171366/2 mattress frame support bar 38 the latter being fixedly secured to the mattress frame 18. In the particular embodiment, the parallelogram mechanisms 26 are each fitted with a pneumatic support piston assembly 40, to facilitate slow and controlled closing of the mattress frame 18 bearing the mattress 20.

A circular support bar 44 traversely extends and rigidly connects respective ends of the mattress frame support bars 38.

An electric motor 48 is secured to the bed frame 14 and is integrated with a gear mechanism 52 from which a extractable piston rod 56 extends with its end pivotally coupled at coupling 58 to a torque restricting link 62 fitted with a tubular section 64 coaxially mounted over transverse support bar 44 and fitted with a coiled spring member 66 as will be discussed hereinafter.

The arrangement is such that the torque restricting link 62 is normally in the position seen in Figs. 2A, 3A and better in Figs. 2B and 3B, respectively, with the coiled spring 66 in a substantially non-tensioned position. In this state, actuating the electric motor 48 in one direction causes retraction of the piston rod 56 upon which the mattress frame support mechanisms 26 pivot into the position of Figs. 1 and 3B, entailing displacement of the mattress frame 18 and the associated mattress 20 into the tilted, open position, facilitating access to the linen compartment 16.

However, upon applying force on the mattress, in the direction of arrow F (Figs. 1 and 4A) a moment of force is applied to the torque restricting link 62, resulting its pivotal displacement in the direction of arrow 70 in Fig. 4B with a corresponding slight lowering of the mattress frame support mechanisms 26, however without retraction of extractable piston rod 56 thus preventing or substantially minimizing any moment of force applied to the electric motor 48 as a result of force F.

Force F may be applied, for example, in the inadvertent event of a person sitting on the bed while attempting to tilt/open the mattress so as to expose the linen compartment, or upon fitting/laying on the mattress whilst it has not been completely closed (namely leveled).

In accordance with an embodiment of the invention, there is provided a micro switch 74 (Figs. 2B, 3B and 4B) whereupon displacement of the torque restricting link into its loaded position of Fig. 4B, it engages the micro switch 74 resulting in disconnecting the electric power supplied to the electric motor 48. In accordance with a 01629096X5-01 7 171366/3 modification of this arrangement, activation of micro switch 74 may cause motor 48 to rotate in an opposite direction.

The spring 66 may be a priori pre-loaded or, it may be in a completely non-tensioned position (as in Figs. 2B and 3B) whereupon the force F deforms it and becomes tense to bias the torque-restricting link 62 back into its unloaded position, an adjusting screw mechanism (not shown) may be provided for pre-loading the spring 66. In accordance with another embodiment of the invention (not illustrated) the extractable piston rod 56 is articulated to the torque-restricting link 62, by means of an adjustable coupling (not shown) wherein adjustment may be obtained by coupling thereof at any one of a plurality of discrete positions, so that a predetermined load is applied on the spring 66.

It is appreciated that also at the event where the mattress is only slightly elevated from the bed frame (say several centimeters) and a load is applied thereto (e.g. a person sitting on the bed) when the motor is still, the mattress frame will displace downwardly under the load until it comes to rest on the bed frame, thus minimizing or avoiding load on the tilting parallelogram mechanisms.

In accordance with a further embodiment of the invention, not illustrated, the mattress frame comprises at least two segments pivotally articulated to one another, at least one of which being pivotal with respect to the bed frame. Where both mattress segments are pivotable with respect to the bed frame, it is possible to articulate each segment thereof with a motor and respectively with a safety mechanism as described hereinabove.

Whilst some embodiments have been described and illustrated with reference to some drawings, the artisan will appreciate that many variations are possible which do not depart from the general scope of the invention, mutatis, mutandis. 01629096\40-01

Claims (15)

- 8 - 171366/3 CLAIMS:

1. A safety mechanism for a tiltable bed, the bed comprising a bed frame supporting a mattress frame secured to the bed frame and an electric motor pivotally articulated to the bed frame with an extractable piston rod extending from the motor and, wherein, the rod is coupled at a remote end thereof to the safety mechanism comprising a torque-restricting link which in turn is pivotally mounted on a transverse support bar of the mattress frame, and whereby the torque-restricting link is biased by a spring member born to bear a predetermined load, said torque-restricting link is pivotally displaceable between an unloaded position adapted to bear substantially the load of the mattress frame and a mattress mounted thereon, and a loaded position upon applying thereto a load exceeding the predetermined load.

2. A safety mechanism for a tiltable bed according to Claim 1 , wherein a micro-switch is fitted such that when the torque-restricting link reaches its loaded position it engages the micro-switch so as to halt operation of the electric motor.

3. A safety mechanism for a tiltable bed according to Claims 1 or 2, wherein the mattress frame is tiltable so as to allow access to a linen compartment of the bed extending there-under.

4. A safety mechanism for a tiltable bed according to any one of Claims 1 to 3, wherein there is further provided an adjusting screw mechanism for pre-loading the spring member.

5. A safety mechanism for a tiltable bed according to any one of Claims 1 to 4, wherein the mattress frame is articulated to the bed frame by a pair parallelogram mechanisms each fitted at a respective side of the bed and wherein a lower end of each pivotal bar is fixedly secured to the bed frame and an upper end of each pivotal bar is fixedly secured to the mattress frame via a mattress frame engaging member, wherein the transverse support bar fixedly extends between said opposite mattress frame engaging members.

6. A safety mechanism for a tiltable bed according to any one of Claims 1 to 5, wherein one or both of the parallelogram mechanisms are pneumatically supported.

7. A safety mechanism for a tiltable bed according to any one of Claims 1 to 6, wherein the torque-restricting link comprises a tubular section coaxially mounted over the transverse support bar. - 9 - 171366/3

8. A safety mechanism for a tiltable bed according to claim 7, wherein the spring member is a coiled spring with one end thereof fixed to the torque-restricting link, and another leg thereof fixed to the support bar.

9. A safety mechanism for a tiltable bed according to any one of Claims 1 to 8, 5 wherein one or both of the torque-restricting link and the remote end of the extractable piston rod is formed with at least two engagement fixtures, whereby pivotal coupling thereof may be at two or more discrete positions.

10. A safety mechanism for a tiltable bed according to any one of Claims 1 to 9, wherein at a substantially flat, horizontal position of the mattress frame the spring 10 member is substantially unloaded.

11. A safety mechanism for a tiltable bed according to any one of Claims 1 to 10, wherein when the mattress frame is at a tilted, elevated position, and is unloaded by an external force overcoming the predetermined force, the torque-restricting link remains at its unloaded position. 15

12. A safety mechanism for a tiltable bed according to any one of Claims 1 to 11, wherein the predetermined load is determined so as to bear the load of the mattress frame with a mattress mounted thereon with linen.

13. A safety mechanism for a tiltable bed according to any one of Claims 1 to 12, wherein the mattress frame comprises at least two segments tiltable with respect to one 20 another and with respect to the bed frame, wherein each mattress segment is associated respectively with an electric motor pivotally articulated to the bed frame with a extractable piston rod extending from the motor and coupled at a remote end thereof to torque-restricting link which in turn is pivotally mounted on a transverse support bar of the mattress frame, whereby the torque-restricting link is biased by a spring member 25 pre-loaded to bear a predetermined load.

14. A bed comprising a bed frame supporting a mattress frame secured to the bed frame, and an electric motor secured to the bed frame with a extractable piston rod extending from the motor and a safety mechanism coupled at a remote end of said extractable piston rod comprising a torque-restricting link which in turn is pivotally 10 171366/2 mounted on a transverse support bar of the mattress frame, whereby the torque-restricting link is biased by a spring member born to bear a predetermined load, said torque-restricting link is pivotally displaceable between an unloaded position adapted to bear substantially the load of the mattress frame and a mattress mounted thereon, and a loaded position upon applying thereto a load exceeding the predetermined load.

15. A safety mechanism according to Claim 1, substantially as hereinbefore claimed and as illustrated in the description and drawings. 01629096\39-02