STAIR CLIMBING TRACKED VEHICLE

• US 3,869,011 A
• Filed: 01/02/1973
• Issued: 03/04/1975
• Est. Priority Date: 01/02/1973
• Status: Expired due to Term

• Current Assignee: Howard Jensen
• Original Assignee: Howard Jensen
• Inventors: Jensen, Howard
• Primary Examiner(s): Goodman, Philip
• Application Number:
  US05/320,115
• Time in Patent Office: 791 Days
• Field of Search: 180/9.24 280/5.22
• US Class Current: 180/9.23
• CPC Class Codes: A61G 5/061 for climbing stairs
• CPC Class Codes: A61G 5/066 with endless belts
• 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
• CPC Class Codes: B62B 9/02 providing for travelling up or down a flight of stairs
• CPC Class Codes: B62D 55/075 Tracked vehicles for ascending or descending stairs, steep slopes or vertical surfacesmagnetic or pneumatic ground-engaging parts B62D55/265; chairs or multi-track cycles specially adapted for invalids A61G5/00

Abstract

A wheel-chair-like stair-climbing vehicle having a pair of main tracks and a pair of auxiliary tracks hinged in front thereof, an automatic (partly and preferably hydraulic) pitch control mechanism controlling the rate of relative rotation between the main and auxiliary tracks, and a self-leveling seat.

Claims

1. A stair-climbing vehicle comprising a pair of main tracks, a pair of auxiliary tracks each being aligned and pivotally joined to a main track adjacent the forward end of said respective main track, propulsion means for driving said main tracks, independently of each other when necessary, self-leveling seat means mounted on said vehicle, automatic pitch-control means mounted to act between each prospective main track and its auxiliary track for limiting at least the rate of pivoting of said auxiliary track with respect to said main track from below said main track towards alignment therewith, said pitch-control means comprising an elbow linkage between each auxiliary and main track pair and having a hydraulic cylinder forming at least part of the linkage forearm and also having a locking means for maintaining the linkage and cylinder in the raised angled position and for locking the linkage and unlocking the cylinder in the lowered position.

2. A vehicle as claimed in claim 1 wherein said seat leveling means comprises a dampened pendulum, two electrical switches respectively activated by said pendulum swinging forward or backward relative to said vehicle when said vehicle pitches forward or backward, the first such switch controlling a solenoid means for closing two additional switches to connect the seat-leveling motor means to operate to bring the seat back up to the level position, the second such switch controlling a second solenoid means for closing two other additional switches to connect the seat-leveling motor means to operate in the opposite direction, neither such first mentioned switches being closed by the pendulum when the seat is in the level position.

3. A vehicle as claimed in claim 1 further comprising castors mounted near the front of said main tracks so as to move from an inoperative position to an operative position extending slightly below the front of the main tracks as the auxiliary tracks are moved from their operative position to their inoperative position.

4. A vehicle as claimed in claim 1 wherein each track comprises an endless tread having an elongated substantially flat lower run extending between at least two sprocket wheels, said tread having interior teeth for non-slip engagement with said sprockets and having exterior cleats, and an anti-friction support positioned on the upper side of the lower run of said tread.

5. A vehicle as claimed in claim 4 where each main track has the lower run of its tread supported in a slightly downwardly bowed shape.

6. A vehicle as claimed in claim 5 where each track at its free end is upwardly and outwardly inclined.

7. A vehicle as claimed in claim 4 further comprising a friction-clutch down fail-safe means mounted in an auxiliary track so as to engage the interior teeth of its tread when the auxiliary track is inclined downwardly and to disengage in any other position for preventing unpropelled downward forward motion of the vehicle.

8. A vehicle as claimed in claim 7 further comprising a ratchet up fail-safe means mounted in a main track so as to swing into locking engagement with said outer cleats of its tread when said main track is inclined upwardly and to swing out of engagement by gravity in any other position for preventing backward motion of the vehicle.

9. A stair-climbing vehicle for transporting a load comprising a parallel pair of main tracks;

a load support carried on said vehicle;

elongated stabilizing means for preventing precipitous pitching forward of said vehicle, being pivotally joined to said vehicle and, when operatively positioned, extending forwardly from such pivot joinder to engage the ground beyond the combined center of gravity of said vehicle and of its load;

propulsion means for driving said main tracks;

rotation retarding means mounted to act between said vehicle and said elongated stabilizing means pivoted thereon for slowing auTomatically at least the rate of pivoting of said elongated stabilizing means upwardly against gravity so as to control the rate of pitching forward of said vehicle;

sensing means mounted on said vehicle for sensing the inclination of said load support and for signaling any significant variation of said load support from the horizontal;

load support leveling means for moving said load support relative to said main track responsive to the signaling of said sensing means so as to keep said load support substantially level and for moving the same at a rate of rotation at least substantially equal to the rate of rotation of said elongated stabilizing means.

10. A vehicle as claimed in claim 9 wherein said elongated stabilizing means is a pair of auziliary tracks each pivoted to a respective main track adjacent the front thereof, and said main and auziliary tracks include non-slip endless belts being a multiplicity of external cleats.

11. A vehicle as claimed in claim 10 wherein said rotation retarding means comprise two hydraulic cylinders each mounted between the vehicle and a respective auxiliary track pivoted thereon, said cylinders being contracted to be retractable under pressure at a controlled predetermined rate.

12. A vehicle as claimed in claim 10 wherein said rotation retarding means comprises two elbow linkages each respectively mounted between each auxiliary track and said vehicle and having a hydraulic cylinder forming at least part of the linkage forearm and also having a locking means for maintaining the linkage and cylinder in the raised angled position and for locking the linkage and unlocking the cylinder in the lowered position.

13. A vehicle according to claim 1 wherein said self-leveling seat means comprises a gimbeled seat.

14. A vehicle according to claim 1 wherein said self-leveling seat means comprises a seat;

sensing means mounted on said vehicle for sensing the inclination of said seat and for signaling any significant variation of said seat from the horizontal;

leveling means for moving said said seat relative to said main track responsive to the signaling of said sensing means so as to keep said seat substantially level and for moving the same at a rate of rotation at least substantially equal to the rate of rotation of said pitch-control means.