Brakes – Wheel – Axially movable brake element or housing therefor
Reexamination Certificate
2001-04-02
2003-07-08
Schwartz, Christopher P. (Department: 3613)
Brakes
Wheel
Axially movable brake element or housing therefor
C188S00400B, C280S011212
Reexamination Certificate
active
06588551
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a braking system for rollers, such as for rollers of inline skates, said braking system providing an anti-flattening or anti-blocking functionality and in which a hydraulic actuation system may be used.
2. Description of Related Art
Conventional force-path translation systems comprise, for example, transmissions or connecting rods. In the area of flexible force-path translation systems, there are the widely used wire cables (so-called Bowden cables) in the low cost segment, and hydraulic systems in the high cost segment.
Wire cables may be produced simply and at reasonable cost, but have various disadvantages. Actuation can occur only by pulling, but not by pushing. The transmission of force is subject to particularly high frictional losses. Branching off may be achieved only with utmost difficulties and with high losses. There is basically no possibility of control, closed-loop control or blocking.
Some of the disadvantages of wire cables are avoided by conventional hydraulic systems, however, hydraulic systems are complicated and expensive. In particular, the transmission losses are extremely small in hydraulic systems, it is possible to transmit forces both by pulling and pushing, branches are possible in a simple manner and practically without losses. Further, it is relatively easy to provide control, closed-loop control or blocking.
Conventional hydraulic systems normally comprise a large number of components. Usually, piston and cylinder assemblies are used a actuation or working elements, such assemblies requiring a large number of components wherein sealing between piston and c~1inder is necessary, and said assemblies involving a complicated structure and a relatively large size.
BRIEF SUMMARY OF THE INVENTION
Therefore, solutions using hydraulics are found exclusively in the high price segment. It is, thus, an object of the present invention to provide a hydraulic system which overcomes the drawbacks of the prior art and which may be produced simply and at low cost. The hydraulic system should be maintenance-free and should operate reliably.
In the present invention, a hydraulic actuation system may be used having at least one actuation/working element being implemented such that a compressing/expanding closed volume is provided by a single piece using appropriate material, hardness and geometry such that the compression/expansion acts directionally in the direction of actuation.
Preferably, the actuation/working element comprises a port or terminal for connection with a conduit, and a main body, said main body forming a chamber for receiving hydraulic fluid, which chamber being connected with said port or terminal but otherwise being closed, said main body further comprising a generally cylindrical outer wall extending in axial direction and two generally planar end walls extending generally perpendicular to the outer wall, wherein at least one of said end walls is formed such that at least a portion thereof is axially displaced upon a change in pressure of the hydraulic fluid in the chamber.
According to a preferred embodiment of the present invention, the end wall consists of an alternating array of relatively rigid portions maintaining their shape and relatively elastic portions providing for displacement, wherein the end wall is preferably circular and consists of an alternating concentric array of at least one relatively elastic ring providing for displacement and a relatively rigid circular center portion maintaining its shape. In addition, the end wall may comprise at least one relatively rigid ring maintaining its shape and at least two relatively elastic rings providing for displacement.
For coaxial applications, the main body may comprise a through-hole defined by a generally cylindrical inner wall extending in axial direction and arranged radially interiorly with respect to the outer wall. In this case, the end wall is preferably ring-shaped and consists of an alternating concentric array of at least one relatively rigid ring maintaining its shape and at least two relatively elastic rings providing for displacement.
In another embodiment of the actuation/working element, the outer wall of the main body is formed such that a circumferential radial channel or groove is formed while maintaining a uniform thickness of material.
The actuation/working element is preferably implemented as a single piece providing a simple structure. It is preferred that the actuation/working element is made of an elastomer or of elastic thermoplastics, e. g. having a hardness of 65°-75° Shore (A). A particularly cost-effective manufacturing method for the actuation/working element is injection molding. However, other methods of manufacturing are possible.
A particularly important part of the hydraulic actuation system is the actuation/working element which normally is connected with a conduit containing hydraulic fluid and which comprises a port or terminal for connection with said conduit, and a main body forming a chamber for receiving hydraulic fluid, which chamber being connected with said port or terminal but otherwise being closed, said main body further comprising a generally cylindrical outer wall extending in axial direction and two generally planar end walls extending generally perpendicular to the outer wall, wherein at least one of said end walls is formed such that at least a portion thereof is axially displaced upon a change in pressure of the hydraulic fluid in the chamber.
Preferably, the end wall consists of an alternating array of relatively rigid portions maintaining their shape and relatively elastic portions providing for displacement, wherein the end wall is preferably circular and consists of a concentric array of at least one relatively elastic ring providing for displacement and a relatively rigid circular center portion maintaining its shape.
The braking system according to the present invention preferably comprises at least one such actuation/working element.
In particular, the hydraulic actuation system is filled with hydraulic fluid and comprises at least one actuation element which upon actuation can cause a change in pressure of the hydraulic fluid, at least one working element which will be displaced in response to the change in pressure of the hydraulic fluid, and a connecting conduit for hydraulic fluid connecting the actuation element with the working element.
This simple hydraulic actuation system is versatile, very reliable and comparatively extremely inexpensive to manufacture.
According to a preferred embodiment of the present invention, the actuation element and the working element may be formed identically.
In a very simple way, a valve may be provided which may control or block the flow of hydraulic fluid in the connecting conduit. For example, if the connection conduit is an at least partly elastic connection tube, the valve may comprise at least one eccentric element which may be used to pinch off the connecting tube.
The above mentioned parts and possibly also other or further parts may form, or result in, a combination kit of hydraulic elements. The various elements may be combined easily. Actuation element(s) or working element(s) may be connected to a connection conduit by simply slipping on and sealing by means of a fixing ring. In a very simple manner, branched systems or systems having multiple circuits may be devised. The elements of the hydraulic element combination kit may be standardized resulting in cost-effective production and warehousing.
The hydraulic actuation system and the actuation/working element according to the present invention may find particularly advantageous application in a braking system for rollers or wheels, such as rollers or wheels for inline skates.
Conventional inline skates have either no braking feature at all or they usually have a braking block, for example made of rubber, mounted behind the last wheel of an inline skate. The conventional provisions for braking are very much insufficient and prone to accidents.
Kammerer Martin
Preuhs Thomas
Conelly Bove Lodge & Hutz, LLP
Schwartz Christopher P.
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