Land vehicles – Wheeled – Occupant propelled type
Patent
1996-12-09
1999-03-16
Hurley, Kevin
Land vehicles
Wheeled
Occupant propelled type
280221, B62M 2902
Patent
active
058820248
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a self propelled trolley.
BACKGROUND OF THE INVENTION
Step ladders or planks supported on scaffolding or trestles are normally used by persons carrying out tasks above their normal reach. When these tasks cover large areas, for example plastering a ceiling, either the step ladder must be moved frequently or a large working platform constructed and subsequently dismantled. Both methods considerably extend the time and effort to perform the task.
SUMMARY OF THE INVENTION
According to the present invention there is provided a self propelled trolley comprising a platform supported on springs on a frame carried on castor wheels and has drive rods suspended from the platform, the drive rods being adapted to engage the ground at an angle other than 90 degrees such that a person standing on the platform by shifting his weight can propel the trolley in any direction or brake to arrest motion.
BRIEF DESCRIPTION OF THE DRAWINGS
Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:
FIG. 1 shows in perspective a rectangular multi-directional version of the self propelled trolley;
FIG. 2 shows its mid cross-section elevation view;
FIG. 3 shows its platform adjusted to a higher level;
FIG. 4 shows the trolley mechanism in operation;
FIG. 5 shows its rod detail with additional spring feature,
FIG. 6 shows in section a flexible rubber coupling between drive rod and platform;
FIG. 7 shows in section a flexible metal spring coupling between drive rod and platform;
FIG. 8 shows in perspective a single directional version of the self propelled trolley;
FIG. 9 shows its mid cross-section as a side view;
FIG. 10 shows its mid cross-section as an end view;
FIG. 11 shows a simple rest location for a drive rod;
FIG. 12 shows a more positive `V` location for a drive rod;
FIG. 13 shows multiple rest locations for alternative drive rod driving directions;
FIG. 14 shows an alternative platform support and spring arrangement;
FIG. 15 shows a round multi directional version of the self propelled trolley; and
FIG. 16 shows its mid cross-section view;
FIG. 17 shows a cross-section view of a trolley braking mechanism in the free position;
FIG. 18 shows the same view of the trolley braking mechanism in the braked position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings 1, 2 and 3, the self propelled trolley shown in FIG. 1 comprises the platform 1 supported by a multiplicity of compression springs 2. These in turn are located on the top of the rigid frame 3. Lugs 5 attached to the frame carry castor wheels 4 and extend outwards so that the platform 1 cannot overhang the wheel contact points on the ground. Suspended from the platform are a multiplicity of angled drive rods 6.
FIG. 2 shows a cross-sectional view of the trolley. Drive rods 6 are shown in more detail. They can be extended in length by sliding the sleeve 7 and are then secured by clamp 8. A typical drive rod 6 is suspended from the platform 1 by the universal pivot 10 and assumes its correct angle by resting against the location stop 12 forced by gravity or more positively by the compression spring 11 to do so. When the person's weight is uniformly distributed on the platform the drive rods are just clear of the ground. To adjust the height of the platform the castor wheels 4 slide in lugs 5 and are secured in position by clamps 9.
FIG. 3 shows the platform 1 at a higher level with castors 4 and drive rods 6 extended. In this example the platform height can be adjusted between 450 mm and 750 mm from the ground.
Operation of the trolley is illustrated in FIG. 4. This is the same cross-sectional view as shown in FIG. 2 but with the weight of the person biased to the left. In reaching the position shown, the left drive rod engages the ground, partly takes the weight of the person and applies a force that moves the trolley to the left. During this movement the angle of the acting drive rod to the vertical increases and other drive rods lift
REFERENCES:
patent: 1268449 (1918-06-01), Gartley
patent: 1383468 (1921-07-01), Lagelbauer
patent: 1677061 (1928-07-01), Toman
patent: 2775488 (1956-12-01), Wingrove
patent: 4275881 (1981-06-01), Armstrong
patent: 4696485 (1987-09-01), Lee
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