Lift system for hospital bed

1. A patient support apparatus comprising

a base frame including a base frame member,

a deck, and

a frame supporting the deck,

at least one lift arm supporting the frame relative to the base frame, the at least one lift arm having a first end and a second end, the at least one lift arm being pivotably coupled to the base frame adjacent the first end of the at least one lift arm, and the at least one lift arm being slidably coupled to the base frame member of the base frame adjacent the second end of the at least one lift arm, and

a link pivotably coupled to the base frame member and pivotably coupled to the at least one lift arm such that the angle between the at least one lift arm and the base frame changes as the position of the second end of the at least one lift arm relative to the base frame changes, wherein the first end of the at least one lift arm is higher in elevation than the second end of the at least one lift arm when the frame is in a raised position relative to the base frame and wherein the first end of the at least one lift arm is lower in elevation than the second end of the at least one lift arm when the frame is in a lowered position relative to the base frame.

2. The patient support apparatus of claim 1 , wherein the second end of the at least one lift arm translates along the base frame member as the frame raises and lowers relative to the base frame.

3. The patient support apparatus of claim 2 , further comprising a slide member to which the second end of the at least one lift arm is coupled, the base frame member including a channel member that supports the slide member, and the slide member slides relative to the channel member as the frame is raised and lowered relative to the base frame.

4. The patient support apparatus of claim 1 , wherein the link is pivotably coupled to one of at least one lift arm about midway between the first and second ends of the at least one lift arm.

5. The patient support apparatus of claim 1 , further comprising at least one actuator that is coupled to the frame to raise and lower therewith and that is operable to pivot the at least one lift arm relative to the frame to raise and lower the frame relative to the base frame.

6. The patient support apparatus of claim 5 , wherein the at least one actuator is operable to move the frame to a Trendelenburg position and to a reverse Trendelenburg position relative to the base frame.

7. The patient support apparatus of claim 5 , further comprising

means for providing pressurized air to a mattress supported by the deck,

means for blocking egress of a patient from the mattress,

foot control means for operating features of the patient support apparatus,

power and control means for providing power and control to the at least one actuator,

rotational support means configured to permit movement of the frame on a floor,

control means for controlling features of the patient support apparatus, the control means being removably coupled to the blocking means,

mattress control means for controlling operation of the mattress,

power supply means for providing power to components of the patient support apparatus, and

network means for communicating between at least two of the power and control means, the control means, the blocking means, and mattress control means.

8. A patient support apparatus comprising

a base frame,

first and second guides coupled to the base frame,

a frame supporting a deck, and

a linkage system coupled between the frame and the base frame, the linkage system comprising

a head link pivotably coupled to the frame and pivotably coupled to a first slide block, the first slide block being slidably received by the first guide,

a foot link pivotably coupled to the frame and pivotably coupled to a second slide block, the second slide block being slidably received by the second guide, and

a guide link pivotably coupled to the base frame and pivotably coupled to one of the head link and the foot link, wherein a distance between the first and second slide blocks increases when the frame is lowered relative to the base frame and wherein the distance between the first and second slide blocks decreases when the frame is raised relative to the base frame.

9. The patient support apparatus of claim 8 , wherein the first and second guides each comprise a channel member having a channel and the first and second slide blocks are received in the respective channels of the first and second guides.

10. The patient support apparatus of claim 8 , further comprising at least one actuator that is coupled to the frame to raise and lower therewith and that is operable to pivot the at least one of the head and foot links relative to the frame to raise and lower the frame relative to the base frame.

11. The patient support apparatus of claim 10 , further comprising a siderail that raises and lowers with the frame and a user input coupled to the siderail and useable to actuate the at least one actuator.

12. A patient support apparatus comprising

a base frame,

a frame supporting a deck, the frame supported relative to the base frame, and

a lift system coupling the frame to the base frame, the lift system including a link having a first end and a second end, the link being pivotably coupled to the frame adjacent the first end of the link, the second end of the link being coupled to a block arranged to slide along the base frame as the link pivots to raise and lower the frame relative to the base frame, and

a guide link having a first end pivotably coupled to the link and a second end pivotably coupled to the base frame, wherein the first end of the link is higher in elevation than the second end of the link when the frame is in a raised position relative to the base frame and wherein the first end of the link is lower in elevation than the second end of the link when the frame is in a lowered position relative to the base frame.

13. The patient support apparatus of claim 12 , wherein the guide link pivots relative to the base frame about a lower pivot axis, the link pivots relative to the frame about an upper pivot axis, and the lift system is configured so that the upper pivot axis remains generally aligned with the lower pivot axis during movement of the frame relative to the base frame.

14. The patient support apparatus of claim 12 , wherein the base frame comprises a channel member having a channel and the block is situated in the channel.

15. The patient support apparatus of claim 12 , wherein the guide link moves to a position parallel with the link during movement of the frame from the raised position to the lowered position.

16. The patient support apparatus of claim 12 , further comprising at least one actuator that is coupled to the frame to raise and lower therewith and that is operable to pivot the link relative to the frame to raise and lower the frame relative to the base frame.

17. The patient support apparatus of claim 12 , wherein the guide link pivots relative to the frame about a lower pivot axis, the link pivots relative to the frame about an upper pivot axis, the guide link pivots relative to the link about an intermediate pivot axis, and the distance between the upper pivot axis and the intermediate pivot axis is generally equal to the distance between the intermediate pivot axis and the lower pivot axis.