Patient transport apparatus having caster assembly biasing mechanisms

Patent metadata

Field	Value
Publication number	US-12005009-B2
Application number	US-202117926702-A
Country	US
Kind code	B2
Filing date	May 27, 2021
Priority date	May 27, 2020
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A patient transport apparatus including a support structure movable between a chair configuration for traversing floor surfaces and a stowed configuration for storage. A seat section is pivotably coupled to the support structure. A caster assembly includes a pin coupled to the support structure and defining a swivel axis, a caster frame arranged to pivot about the swivel axis between a plurality of caster orientations, a wheel coupled to the caster frame and arranged for engagement with the floor in the chair configuration, and a biasing mechanism interposed between the caster frame and the pin. The biasing mechanism urges the caster frame toward a stowed caster orientation in response to disengagement between the wheel and floor surfaces occurring as the support structure moves from the chair configuration to the stowed configuration.

First claim

What is claimed is:

1. A patient transport apparatus comprising: a support structure movable between a chair configuration for traversing floor surfaces and a stowed configuration for storage; a seat section for supporting the patient, the seat section being pivotably coupled to the support structure; and a caster assembly comprising: a pin coupled to the support structure for concurrent movement between the chair configuration and the stowed configuration, the pin defining a swivel axis; a caster frame arranged to pivot about the swivel axis between a plurality of caster orientations including a stowed caster orientation, a wheel coupled to the caster frame, supported for rotation about a wheel axis, and arranged for engagement with the floor surfaces when the support structure is in the chair configuration, and a biasing mechanism interposed between the caster frame and the pin to urge the caster frame toward the stowed caster orientation in response to disengagement between the wheel and the floor surfaces occurring as the support structure moves from the chair configuration to the stowed configuration.

2. The patient transport apparatus as set forth in claim 1 , wherein the biasing mechanism comprises a first magnetic element operatively attached to the pin, and a second magnetic element operatively attached to the caster frame adjacent to the first magnetic element, the second magnetic element being arranged in magnetic relationship with the first magnetic element to urge the caster frame about the swivel axis toward the stowed caster orientation as the support structure moves from the chair configuration to the stowed configuration.

3. The patient transport apparatus as set forth in claim 2 , wherein the biasing mechanism further comprises a third magnetic element operatively attached to the caster frame adjacent to the first magnetic element, the third magnetic element being arranged in magnetic relationship with the first magnetic element to urge the caster frame about the swivel axis toward the stowed caster orientation as the support structure moves from the chair configuration to the stowed configuration.

4. The patient transport apparatus as set forth in claim 3 , wherein the first magnetic element is positioned between the second magnetic element and the third magnetic element.

5. The patient transport apparatus as set forth in claim 3 , wherein the first magnetic element defines a first pin pole and an opposing second pin pole;
wherein the second magnetic element defines a first frame pole attracted to the first pin pole;
wherein the third magnetic element defines a second frame pole attracted to the second pin pole;
wherein the second magnetic element further defines a first reference pole opposing the first pin pole; and
wherein the third magnetic element further defines a second reference pole attracted to the first pin pole.

6. The patient transport apparatus as set forth in claim 2 , wherein the pin of the caster assembly comprises a carrier supporting the first magnetic element, and a shank extending from the carrier along the swivel axis, the shank being coupled to the support structure.

7. The patient transport apparatus as set forth in claim 6 , wherein the pin defines a pin bore formed extending transversely through the swivel axis and shaped to receive the first magnetic element.

8. The patient transport apparatus as set forth in claim 6 , wherein the caster assembly comprises a bearing operatively attached to the caster frame and disposed along the shank of the pin adjacent to the carrier to support the caster frame for pivoting about the swivel axis.

9. The patient transport apparatus as set forth in claim 8 , further comprising a holder operatively attached to the caster frame for supporting the second magnetic element, the holder defining a seat shaped to receive at least a portion of the carrier of the pin.

10. The patient transport apparatus as set forth in claim 9 , wherein the holder comprises a retainer disposed adjacent to the seat and defining a retainer bore shaped to receive the second magnetic element.

11. The patient transport apparatus as set forth in claim 10 , wherein the carrier of the pin defines a pilot face shaped to engage the seat of the holder when the support structure is disposed in the chair configuration for traversing the floor surfaces; and wherein engagement between the pilot face and the seat results in at least partially resists rotation of the caster frame about the swivel axis to overcome magnetic attraction occurring between the first and second magnetic elements of the biasing mechanism.

12. The patient transport apparatus as set forth in claim 1 , wherein the biasing mechanism comprises a spring extending between the pin and the caster frame to urge the caster frame about the swivel axis toward the stowed caster orientation as the support structure moves from the chair configuration to the stowed configuration.

13. The patient transport apparatus as set forth in claim 12 , wherein the spring of the biasing mechanism is further defined as an extension spring; and
wherein the pin of the caster assembly comprises a first spring mount, the caster frame comprises a second spring mount, and the extension spring extends between each of the first and second spring mounts.

14. The patient transport apparatus as set forth in claim 1 , wherein the pin of the caster assembly comprises a guide body defining a ramp surface, and a shank extending from the guide body along the swivel axis, the shank being coupled to the support structure.

15. The patient transport apparatus as set forth in claim 14 , wherein the caster assembly comprises a bearing operatively attached to the caster frame and disposed along the shank of the pin adjacent to the guide body to support the caster frame for pivoting about the swivel axis.

16. The patient transport apparatus as set forth in claim 15 , wherein the biasing mechanism comprises a follower operatively attached to the caster frame and disposed in sliding contact with the ramp surface of the guide body of the pin to urge the caster frame about the swivel axis toward the stowed caster orientation as the support structure moves from the chair configuration to the stowed configuration.

17. The patient transport apparatus as set forth in claim 16 , wherein the ramp surface of the guide body of the pin extends at least partially helically around the swivel axis and is arranged to disengage from the follower when the support structure operates in the chair configuration.

18. The patient transport apparatus as set forth in claim 16 , wherein the bearing travels at least partially along the shank of the pin to bring the follower into engagement with the ramp surface of the guide body when the support structure moves from the chair configuration to the stowed configuration.

19. The patient transport apparatus as set forth in claim 1 , further comprising a rear wheel operatively attached to the support structure, spaced from the caster assembly, and configured to remain in engagement with the floor surfaces as the support structure moves from the chair configuration to the stowed configuration.

20. The patient transport apparatus as set forth in claim 1 , further comprising a back section for supporting the patient, the back section being operatively attached to the support structure and defining a first plane;
wherein the seat section defines a second plane arranged at a seat angle relative to the first plane;
wherein the seat angle increases as the supp

Assignees

• Stryker Corp

Inventors

• Pfeiffer Trey Thomas
• Matheny Nathan W
• Grossman Patrick
• Kammers Adam

Classifications

• A61G5/0883

  having locking means for maintaining a folded or unfolded condition · CPC title

• A61G5/061

  for climbing stairs · CPC title

• A61G5/10

  Parts, details or accessories · CPC title

• B60B33/025

  by using form-fit, e.g. front teeth · CPC title

• B60Y2200/84

  Wheelchairs · CPC title