Support wheel
Jockey wheel is a term from vehicle technology. Support wheels are usually auxiliary wheels that are not used for the regular movement of a vehicle. They prevent the vehicle from falling over. To distinguish them are the safety wheels - the anti-tip - to persons wheelchairs against the post tipping over when driving uphill.
Ground vehicles
Loader wagon with support wheel (left)
Support wheels can be found - often one on each side - on the following vehicles:
- For small bicycles for children, designed to prevent tipping over when learning to ride a bike. The educational value is considered to be low, as the training wheels hardly allow them to train their sense of balance . The steering behavior also changes when one of the additional wheels touches down. The wheel then behaves like a multi-lane vehicle and, like a tricycle, can no longer accept steering impulses . In order to prevent the continual change of steering behavior, children ride permanently on a support wheel, which can lead to posture and back damage. Apart from that, the risk of falling is greater on the edge of the sidewalk and on street gutters. Alternatively, 2000, the year since about wheels for children from 2 years available in which the legs take over the supporting effect.
- Suspension on therapy wheels for people with balance or movement disorders.
- On other single-track vehicles to avoid falling over when stationary (see Ecomobile ).
- On semitrailers of articulated lorries , in order to enable unsaddling using the supports while standing .
- On the drawbars of single-axle trailers such as caravans and load trailers, in order to keep the trailer in balance when it is stationary and uncoupled.
- Snow plows have - behind the plow edge - support wheels or skids to improve guidance close to the ground. There are also larger, laterally inclined manual snow plows with 2 wheels that build up cornering force in order to move the snow along a path across to one side.
- In the case of agricultural attachments (for example a plow ), the working depth is often determined using a support wheel (feeler wheel).
- Under unicyclists , cyclists are usually referred to as support cyclists, since a second wheel is only viewed as a support wheel, which, like the support wheels on children's bikes, becomes superfluous with a little practice.
Training wheels on children's bikes are firmly attached next to the rear wheel; if there is a slight slope (or uneven ground), they touch down. On the other vehicle types, they are movably or height-adjustable or (in the case of Ecomobile) at the end of swing-out support arms.
Glider
Support wheel on the SF 25
Gliders have different types of training wheels:
- Small under the wing tips to a tilting to the ground during the landing at the last rolling wing support.
- Self- launching motor gliders with support wheels with a diameter of 15 cm on foldable supports under the wing center do not need any assistants who would otherwise have to keep the wing ends level until they reach about 20 km / h. If the sailor rolls horizontally, both support wheels are about 15 cm above the ground.
- For towing larger sailors on the ground without a helper, a support wheel with a diameter of about 50 cm is clamped to only one wing, under the weight of which the sailor leans slightly towards this side and is supported. At the front, the central main landing gear bears the main load. A kuller is mounted in the area of the small, non-steerable rear wheel, so that the glider can also be pulled in curves and even rotated around its vertical axis simply by pulling the pull rod on the tow hook .
Other uses
- Support wheels can support wide sliding, swing and folding gates.
- There are roller steps and step ladders , the rollers of which are used to move the climbing aid without load and which compress when loaded. The climbing aid then stands firmly on its feet next to the rollers. The support wheels of larger scaffolding are raised or lowered using screw or lever mechanisms.
- The top part of a rope ladder rolls up the house facade with the help of 2 support wheels.
- Support castors on office chairs roll slightly when loaded, but slow down the unloaded armchair somewhat.
literature
- Walter Hefti: Cable cars all over the world. Inclined rope levels - funiculars - cable cars. Springer Verlag, Basel 1975, ISBN 3-0348-6569-4 .
- Stefan Hesse: Industrial robot practice. Automated handling in production. Vieweg Verlag, Wiesbaden 1998, ISBN 3-322-88982-3 .