AU785177B2 - A hospital bed - Google Patents

Description

S&FRef: 601132

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Medicraft Australia Pty. Limited 72-84 Shepherd Street Marrickville New South Wales 2204 Australia Bela Martha Spruson Ferguson St Martins Tower,Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) A Hospital Bed ASSOCIATED PROVISIONAL APPLICATION DETAILS [33] Country [31] Applic. No(s) AU PR6653 [32] Application Date 27 Jul 2001 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815c 1 A HOSPITAL BED Field of the Invention The present invention relates to hospital beds.

Background of the Invention Hospital beds are now frequently provided with electric motors which adjust the height, and/or inclination and/or configuration of the bed.

In respect of altering the inclination of the bed frequently two electric motors are employed, each couple to a respective location on the platform supporting the bed mattress. These locations are longitudinally spaced.

A problem with the above discussed hospital beds is that different loads are applied to the electric motors as the patient's weight is not evenly distributed on the bed.

This can result in the bed slowly going into a tilt position. A further problem of the above discussed beds includes the support being inclined when not required.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.

Threi Summary of the Invention There is firstly disclosed herein a hospital bed including: a wheeled base to rest on a floor surface; 20 a patient support platform having longitudinal opposite ends and upon which a patient is to be supported; a first linkage assembly extending between the base and platform, and being S•attached to said platform at a first position; oo a second linkage assembly extending between the base and platform, and attached to the support at a second position, said second position being longitudinally •"spaced from said first position; first electric motor means, said first means being connected to said first linkage assembly to cause movement thereof to change the height and inclination of the platform; second electric motor means, said second means being connected to said second linkage assembly to cause movement thereof to change the height and inclination of the platform; and (R.\AUBT Docunnnts 2001 200208644.dc:KEH a third linkage assembly, said third assembly coupling the first and second assemblies to limit the inclination of said platform.

There is further disclosed herein a hospital bed including: a wheeled base to rest on a floor surface; a patient support platform having longitudinal opposite ends and upon which a patient is to be supported; a first linkage assembly extending between the base and platform, and being attached to said platform at a first position; a second linkage assembly extending between the base and platform, and attached to the support at a second position, said second position being longitudinally spaced from said first position; first electric motor means, said first means being connected to said first linkage assembly to cause movement thereof to change the height and inclination of the platform said first linkage assembly applying a load to said means; second electric motor means, said second means being connected to said second linkage assembly to cause movement thereof to change the height and inclination of the platform said second linkage assembly applying a load to said second means; and means extending between the first and second linkage assemblies to aid in equalising the loads applied to the electric motors means.

Brief Description of the Drawings A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a schematic side elevation of a hospital bed; Figure 2 is a schematic plan view of a linkage employed in the hospital bed of Figure 1; and Figure 3 is a schematic perspective view of a control mechanism for the bed of Figures 1 and 2.

Detailed Description of the Preferred Embodiments In the accompanying drawings there is schematically depicted a hospital bed The hospital bed 10 includes a base 11 provided with four wheels 12. Supported by the base 11 is a platform 13 which would receive a mattress upon which a patient would rest.

[R.\LIBTTMDocumCn 2001 2002108644 doc.KEH 3 Extending between the base 11 and platform 13 is a first linkage assembly 14 and a second linkage assembly 15. The linkage assembly 14 is attached to the platform 13 at a location 16 spaced longitudinally from the location 17 at which the linkage assembly 15 is attached to the platform 13.

The linkage assembly 14 includes a first link 18 fixed to the platform 13 but pivotally attached to an arm 19. The arm 19 is pivotally mounted on the base 11 by means of a shaft 20 which is rotatable about a generally horizontal axis extending transverse of the bed 10. Also attached to the shaft 20 is a further arm 21. The link 18 is pivotally attached to the arm 19 for pivoting movement about a pivot pin 23 providing a generally transverse horizontal pivot axis.

The linkage assembly 15 includes a first link 22 pivotally attached to the platform 13. Pivotally attached to the link 22 is an arm 24. The arm 24 is pivotally supported by a shaft 25 providing a generally horizontal transverse pivot axis. Also attached to the shaft 25 is a further arm 26.

Is The link 22 is attached to the platform 13 for pivoting movement relative thereto about a generally horizontal transverse axis. In addition, the link 22 pivots relative to the arm 24 about a pin 27 that provides a generally horizontal transverse pivot axis.

:i The platform 13 has longitudinal ends 28 (head) and 29 (foot), with the location 16 being spaced toward the end 28 while the location 17 is spaced toward the end 26.

Associated with the linkage 15 is an electric motor 30 which is provided with a telescopically moved shaft 31. The shaft 31 is pivotally attached to the arm 26 so that extension and retraction of the shaft 31 causes pivoting of the arms 24 and 26 in unison.

Operation of the electric motor 30 would therefore raise and lower the end 29 and change the inclination of the platform 13.

Extending between the lower extremities of the arms 21 and 26 is a third linkage assembly 32. The linkage assembly 32 includes a pair of tubular members 33 pivotally attached to the lower extremity of the arm 21. Telescopically received within the tubular members 33 are further tubular members 34, which members 34 are attached to a shaft The shaft 35 is attached to the lower extremity of the arm 26.

Extending between the base 11 and outer tubular members 33 is a second actuator 55 including an electric motor 37. The electric motor 37 includes a shaft 38 which is telescopically extended and retracted to cause movement of the outer tubular members 33 to which it is pivotally attached.

(R.\LIBMDocu nts 2001 20021]08644 doc:KEH Operation of the electric motor 37 will cause pivoting of the arms 19 and 21 and therefore movement of the end 28 and therefore change the inclination of the platform 13.

The telescopic relative movement between each tubular member 34 and its associated outer tubular member 33 is limited by the use of installed limit switches 50 to 53 placed on cross members 48 and 46. As there are two actuators 54 and 55 being used and each of these motors has both forward and reverse movement available, it is required that four limit switches 50 to 53 are installed so that each motor can be limited at both full extended and full retracted positions. When actuator rod 31 is fully extended and actuator rod 38 is fully retracted. The bed 10 will be in the full head end 28 down position. Limit switches 50 and 51 will make contact with plate 49. This switching will break the circuit for actuator 30 in the extending direction and actuator 37 in the retracting direction.

Conversely, when actuator rod 31 is fully retracted and actuator rod 38 is fully extended the bed 10 will be in the full foot end 29 down position. Limit switches 52 and 53 will make contact with plate 54. This switching will break the circuit for actuator 30 in the retracting direction and actuator 37 in the extending direction.

The member 40 and 54 are mounted on the members 34 by bolts 35 which pass through slots 36 in members 33.

.Further coupling the tubular members 33 and 34 is a gas strut 39. The gas strut 39 is housed in mounting 42, which is fixed to cross brace 40. More particularly the gas S 20 strut 39 has a cylinder body, which allows it to telescope in and out of mounting 42. This is required for the foot end down position. When the head end down position is required the gas cylinder is compressed. The downward weight of the bed 10 and patient combined with the pushing force of actuator 30 is sufficient to overcome the gas strut 39.

The gas strut 39 is always acting in assistance of the head end 28 actuator 37. In addition, 25 the gas strut 39 has an adjustment bolt 43 together with a lock nut 44. This bolt 43 allows fine adjustment of the gas strut 39 pre-loading, enabling more or less force to be applied lever 21 as required.

Extending from the cylinder body 41 is a piston rod 45 secured to the tubular members 43 by means of a cross brace 46. More particularly the rod 45 is secured to the cross brace 46 by means of a nut 47.

The gas strut 39 provides a force that urges the linkage assemblies 14 and 15 to move in unison. More particularly the gas strut 39 aids in compensating for the patient's weight not being evenly distributed on the platform 13 and therefore evenly distributed between the links 18 and 22. For example, under normal conditions with a patient on the [R \LBfDocumnts 2001 2002108644.doc:KEH bed 10, the centre of gravity is positioned toward the head end 28 of the bed 10. When the platform 13 is to be raised, both motors 30 and 37 are operated. The arms 21 and 26 will pivot in unison due to the gas strut 39, even though the centre of gravity is toward the end 28. Operation of either of the motors 30 and 37 can cause relative movement between the linkage assemblies 14 and 15 in order to change the inclination of the platform 13. The electric motors 30 and 37 supply sufficient force to their associated rods 31 and 38 to overcome the force provided by the gas strut 39.

Associated with the motors 30 and 31 is a control mechanism 40 which is operable by a hand held pad 41 to deliver electric energy to the motors 30 and 31. A user operating the control mechanism 40 may make a selection in which the platform 13 is at an upper or a lower limit. In such an instance the electric motors 30 and 37 are operated until their respective shafts 31 and 38 are extended the required length.

The platform 13, when at its uppermost limit and its lower most limit, is generally horizontal. That is, when an operator selects a button on pad 41 to position the is platform 13 at its upper or lower limit, the control mechanism 40 will operate actuators and 31 and therefore the position of platform 13. That is the actuators 30 and 31 will be operated until the platform 13 is generally horizontally oriented. In this respect, it should be appreciated that actuators 54 and 55 both have internal limit switches for both fully extended and fully retracted positions. This switching limits the high (fully extended) position and the low (fully retracted) position. It also invokes self-levelling of platform 13 at either of these two positions. This function could be regarded as "self-levelling memory". When a particular orientation of the platform 13 is selected, the control mechanism 40 will generate signals for the motors 30 and 31 to move it from its start position to the required orientation.

ooo•* [R:\LIBTnDocumcnts 2001 2002]08644 doc KEH

Claims (4)

1. A hospital bed including: a wheeled base to rest on a floor surface; a patient support platform having longitudinal opposite ends and upon which a patient is to be supported; a first linkage assembly extending between the base and platform, and being attached to said platform at a first position; a second linkage assembly extending between the base and platform, and attached to the support at a second position, said second position being longitudinally spaced from said first position; first electric motor means, said first means being connected to said first linkage assembly to cause movement thereof to change the height and inclination of the platform; second electric motor means, said second means being connected to said second linkage assembly to cause movement thereof to change the height and inclination of the platform; and a third linkage assembly, said third assembly coupling the first and second assemblies to limit the inclination of said platform. A hospital bed including: a wheeled base to rest on a floor surface; a patient support platform having longitudinal opposite ends and upon which a patient is to be supported; a first linkage assembly extending between the base and platform, and being attached to said platform at a first position; a second linkage assembly extending between the base and platform, and 25 attached to the support at a second position, said second position being longitudinally ooo• spaced from said first position; first electric motor means, said first means being connected to said first linkage Uassembly to cause movement thereof to change the height and inclination of the platform, goe said first linkage assembly applying a load to said first means; second electric motor means, said second means being connected to said second linkage assembly to cause movement thereof to change the height and inclination of the platform, said second linage assembly applying a load to said second means; and means extending between the first and second linkage assemblies to aid in equalising the loads applied to the electric motors means.

I RALI BmDocurmnts 2001 2002]08644 doc.KEH

3. The hospital bed of claim 1, wherein said hospital bed further includes means extending between the first and second linkage assemblies to aid in equalising loads applied to the electric motor means.

4. The hospital bed of claim 2, further including a third linkage assembly, said third assembly coupling the first and second assemblies to limit the inclination of said platform. A hospital bed substantially as hereinbefore described with reference to the accompanying drawings. Dated 4 August, 2006 Medicraft Australia Pty. Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON .e ee ::o oooe (RALBMDocunits 2001 2002J08644 doc:KEH