Stair-climbing carrier

• US 4,027,889 A
• Filed: 11/10/1975
• Issued: 06/07/1977
• Est. Priority Date: 11/10/1975
• Status: Expired due to Term

• Current Assignee: Kando Incorporated
• Original Assignee: Kando Incorporated
• Inventors: Krofchalk, Gary F., Dodds, Andrew D.
• Primary Examiner(s): Goodman, Philip
• Application Number:
  US05/630,093
• Time in Patent Office: 575 Days
• Field of Search: 280/5.22, 280/5.24, 280/5.3, 280/5.28, 280/5.32, 280/28.5, 305/1, 305/2, 180/9.22, 187/11, 214/1, 214/2
• US Class Current: 280/5.22
• CPC Class Codes: B62B 2301/256 by using endless belts
• CPC Class Codes: B62B 5/02 providing for travelling up or down a flight of stairs chairs or multi-track cycles specially adapted for invalids A61G5/00

Abstract

A tracked, stair-climbing carrier for carrying loads up and down stairs and across floors. The carrier includes a frame mounting a pair of parallel endless tracks at its sides for moving the frame forwardly and rearwardly along a floor and up and down stairs. An upper, load-receiving deck is slideably carried by the frame and is movable forwardly and rearwardly to adjust the center of gravity of the carrier and load and permits the rearward end of the deck to rest upon the floor when the frame has been tilted to an acute angle with the floor. A load-bearing lifting arm, receivable in the frame between the tracks, may be swung downwardly to cause the forward end of the frame to tilt upwardly at an acute, stair-engaging angle to the floor, the tilted frame with the deck and load being supported rearwardly by the tracks or supplemental wheels and forwardly by casters at the forward, downwardly swung end of the lifting arm, whereupon the tilted, fully supported and balanced load may be moved along the floor with the tracks in position to engage stairs, ramps, curbs, etc.

Claims

1. A tracked carrier for carrying loads in a tilted position across floors and up and down stairs, and comprising

an elongate load-carrying frame with means to which a load may be attached along the elongate frame, the frame having upper and lower ends,

a spaced pair of elongate, parallel, endless tracks extending along opposite sides of the frame and being movable in elongated paths to drive the frame along a supporting surface and up and down stairs, the tracks extending beyond the lower end of the frame to support the frame upon such a supporting surface when the frame is tipped to upright and inclined positions;

a lifting arm pivotally mounted at one end to the frame adjacent the lower end thereof, and having a floor-engaging caster at its other end, the lifting arm being configured for reception within the frame between the tracks when swung upwardly into a retracted position with the caster nearer the upper than the lower end of the tracks, and the arm being swingable to near horizontal position when the elongate frame is supported in upright position on the lower ends of the elongate endless tracks and against a load to be tipped into inclined transport position; and

means for controllably swinging the lifting arm outwardly from its retracted position to support the frame in an inclined angle with the floor for travel therealong on the caster wheel and the lower ends of the elongate endless tracks.

2. The carrier of claim 1 wherein said means for swinging the lifting arm comprises an axially extensible thruster extending between the lifting arm and the frame of the carrier.

3. A tracked carrier for carrying loads in a tilted position across floors and up and down stairs, and comprising

a frame carrying at its sides a spaced pair of parallel, endless tracks movable in elongated paths to drive the frame along a surface and up and down stairs;

a lifting arm pivotally mounted at one end to the frame adjacent the rear of the frame and having a floor-engaging caster at its other end, the lifting arm being configured for reception within the frame between the tracks when swung upwardly into a retracted position with the caster nearer the forward than the rearward end of the tracks; and

means for controllably swinging the lifting arm outwardly from its retracted position to tilt the frame into an acute, stair-engaging angle with the floor with the center of gravity of the carrier spaced rearwardly of the caster, whereby the tilted carrier and any load carried thereby are balanced and supported rearwardly by the rearward ends of the tracks and forwardly by the caster for movement along a floor, said means for swinging the lifting arm comprises a pair of thrusters lying in a common plane and a bracket pivotally connected to the forward ends of the thrusters and pivotally connected to the forward end of the frame to permit pivoting of the bracket about an axis normal to the plane of the thrusters for accommodation of unequal rates of extension or retraction of the thrusters, and a thruster-actuated cam pivotally mounted to the lifting arm for rotation in response to extension or retraction of the thrusters, and a cam follower mounted to the frame, the cam being configured to force the cam follower upwardly in response to extension of the thrusters to swing the lifting arm outwardly from the frame.

4. A tracked carrier for carrying loads in a tilted position across floors and up and down stairs, and comprising

a frame carrying at its sides a spaced pair of parallel, endless tracks movable in parallel, elongated paths to drive the frame along a surface or up and down stairs;

a lifting arm swingably mounted at one end to the frame and having a floor-engaging caster at its other end, the lifting arm being configured for reception within the frame between the tracks when swung upwardly into a retracted position; and

means for controllably swinging the lifting arm outwardly from its retracted position to tilt the frame into an acute, stair-engaging angle with the floor and comprising a cam with an arcuate camming surface pivotally mounted to the lifting arm along its length, a cam follower mounted to the frame in cam-engaging position, and at least one axially extensible thruster mounted at one end to the frame and at its other end to the cam to rotate the latter, the camming surface being configured to force the cam follower upwardly in response to rotation of the cam by extension of the thruster, thereby initiating outward movement of the lifting arm from the frame.

5. The carrier of claim 4 including a spaced pair of axially extensible thrusters lying in a common plane, and including a bracket pivotally and individually mounting the thrusters at their forward ends to the forward end of the frame and pivotal about an axis normal to the plane of the thrusters to accommodate unequal rates of thruster extension.

6. The carrier of claim 5 including a separate power source for each thruster to extend and retract the same, each source of power being mounted to the respective thruster and movable with the thruster as the latter is extended and retracted.

7. The carrier of claim 6 including a bracket holder pivotally mounting the thruster bracket to the forward end of the frame for pivotal movement about a transverse axis and permitting the thrusters to change angles with respect to the floor as they are extended and retracted.

8. An easily loaded and unloaded tracked carrier for carrying loads in a tilted position across floors and up and down stairs and comprising

a frame carrying at its sides a spaced pair of parallel, endless tracks movable in elongated paths to drive the frame along a floor and up and down stairs;

a lifting arm having a caster at one end and mounted at its other end to the frame, the lifting arm being movable outwardly from the frame to tilt the frame forwardly and upwardly into an acute angle with the floor with the center of gravity of the frame falling rearwardly of the caster;

an upper deck for bearing a load and slideably carried by the frame for movement rearwardly thereof to permit the rearward end of the deck to project rearwardly of the rearward end of the tracks; and

load-adjustment means for moving the deck forwardly or rearwardly of the frame to adjust the center of gravity of the carrier and its load over the tracks and permitting the rearward end of the deck to rest on the floor to the rear of the tracks when the frame has been lifted to form said acute angle with respect to the floor, to thereby facilitate loading and unloading the carrier.

9. The carrier of claim 8 wherein the deck, at its rearward end, includes an outwardly projecting toeplate for engaging loads and preventing movement of the loads rearwardly of the deck.

10. The carrier of claim 8 wherein the load adjustment means includes a frame-mounted winch and a winch cable extending from the winch and attached to the deck, and wherein the frame and deck have coacting guides and guide followers for guiding the deck forwardly and rearwardly of the frame in response to operation of the winch.

12. The carrier of claim 8 including a platform releasably mounted to the rearward ends of the deck and extending outwardly from the deck, the platform having at least one rearwardly extending caster at its outer end in position to engage the floor when the deck is in a raised, upright position, whereby the carrier and any load thereon is supported forwardly by the rearward end of the tracks and rearwardly by at least one platform caster.

13. The carrier of claim 8 including bogie wheels releasably mounted to the frame adjacent the rearward ends of the tracks and oriented to engage and disengage the floor as the carrier is tilted to varying predetermined angles with the floor.

11. An easily loaded and unloaded, tracked, stair-climbing, adjustable-balance carrier for carrying loads up and down stairs and across floors, and comprising

a generally flat, elongated frame having sprockets at its front and rear, and a pair of spaced, endless, parallel lugged tracks trained over the sprockets for movement of the frame forwardly or rearwardly;

a lifting arm comprising a pair of spaced, generally parallel and coextensive lever arms each mounted at one end to the frame adjacent the rear of the frame and having a floor-engaging caster at its other end, the lever arms being configured for reception within the frame between the tracks when swung upwardly into a retracted position with the casters nearer the forward than the rearward end of the tracks;

means for swinging the lifting arm outwardly from its retracted position to tilt the frame into an acute, stair-engaging angle of about 30°

- 40°

with the floor with the center of gravity of the carrier spaced rearwardly of the casters, and including an elongated, extensible and retractable thruster pivotally mounted at opposite ends to the frame and arm to rotate the latter, and a bracket pivotally mounted to the forward end of the frame and having a pivot separately mounting the forward end of the thruster thereto;

an upper deck slidably mounted on the frame for carrying a load and slidable along the frame forwardly thereof and also rearwardly thereof to the extent that the rearward end of the deck projects beyond the rearward end of the tracks to the floor when the frame is in its tilted position; and

a drive mechanism connecting the deck and frame to move the deck and any load borne by the deck forwardly and rearwardly of the frame;

whereby the carrier in a tilted position, and any load carried thereby, may be balanced and supported rearwardly by the rearward ends of the tracks and forwardly by the casters for movement along a floor and whereby the load may be adjusted so that the center of gravity of the load and carrier falls safely over the tracks for climbing of stairs.

14. A tracked carrier for carrying loads in a tilted position across floors and up and down stairs, and comprising:

an elongate load-carrying frame with means to which a load may be attached along the elongate frame, the frame having upper and lower ends,

a pair of elongate, parallel and endless tracks extending along opposite sides of the frame and being movable in elongated paths to drive the frame along a supporting surface and up and down stairs, the tracks extending beyond the lower end of the frame to support the frame upon such a supporting surface when the frame is tipped to upright and inclined positions;

a lifting arm having an inner end pivotally mounted on the frame adjacent the lower end thereof and having an outer end with a floor-engaging caster thereon, the lifting arm being configured for reception within the frame between the tracks when swung into retracted position;

a source of rotary power on the frame and including drive mechanism connected to said endless tracks and applying driving impetus to both of the tracks, said drive machanism including differential gearing through which such power is applied to the separate tracks, and

means for controllably swinging the lifting arm outwardly from its retracted position to support the frame in an inclined angle with the floor for travel therealong on the caster wheel and the lower ends of the elongate endless tracks, the differential gearing and caster wheel facilitating steering during travel along the floor, and the differential gearing permitting steering during travel on a stairway with the caster wheel retracted.

15. The tracked carrier according to claim 14 and including a load-carrying platform having a lower end adjacent the lower end of the frame, the platform being slidably mounted on the frame and movable to extend the lower end of the platform downwardly beyond the lower end of the frame and beyond the adjacent end of the endless track, and the platform also being slidable upwardly along the frame to a position wherein the lower end of the platform is disposed between the ends of the frame and between the ends of the endless tracks thereon.