192 clutches and power-stop control – Clutch and brake – Peripheral brake
Reexamination Certificate
2001-03-19
2003-03-04
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutch and brake
Peripheral brake
C074S473130, C074S502200, C074S535000, C192S215000
Reexamination Certificate
active
06527095
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a one-way force transmission with a position block. This one-way force transmission is used in ratchet mechanisms, for example in lever switches, rotary-grip switches, trigger switches for the actuation of gear shifts on bicycles or in ratchets for tools, vehicle jacks and other applications where one-way force transmission and a resetting of the actuating element into the initial position are desired.
Ratchet mechanisms, such as used, for example, in switches for the actuation of bicycle gear shifts, are known from the patent specifications EP 0371429 A2, EP 0647557 B1, FR 2701917 and GB 2012893 A.
These switches contain a shift lever for winding up or winding on the shift assembly and a release lever or a release button for releasing a positioning device. The shift lever rotates the wind-on reel, via a one-way transmission element prestressed in the engagement direction, counter to a resetting spring acting on the shift assembly. The positioning device holds the wind-on reel in the unopened position and thus counteracts the resetting spring which acts on the shift assembly. The positioning action can be canceled in steps via a release button prestressed by a spring. After actuation, the shift lever is likewise returned into its initial position by a resetting spring and at the same time ratchets the sprung one-way transmission element via the sawtooth contour of the wind-on wheel.
It is necessary, in order to implement this wind-up and release function, to have a large number of structural parts, such as, for example, a shift lever with a resetting spring, a one-way transmission element with a prestressing spring, a wind-on reel with a sawtooth contour, a positioning device with positioning pawls and a prestressing spring and also a release button with a resetting spring.
This multiplicity of structural parts coordinated exactly with one another leads to a considerable outlay in terms of production and assembly and requires a corresponding construction space in the switch housing. Moreover, these structural parts must be designed with high stability due to the requirement of a long useful life, which also has an effect on the weight and costs of the switch unit.
SUMMARY OF THE INVENTION
The object of the present invention is, without the overall function being impaired, to reduce the number of structural parts required, to minimize the outlay in terms of manufacture and the outlay in terms of assembly and to reduce the weight and construction space.
This object is achieved, according to the present invention, essentially by a plurality of functions being combined into one structural part:
a) shift lever resetting and prestressing of the one-way transmission element by means of only one spring, relinquishment of the prestressing spring,
b) the shift lever and one-way transmission element are one structural part, relinquishment of the separate one-way transmission element and of the prestressing spring,
c) the shift lever, one-way transmission element and resetting spring are one structural part, relinquishment of the separate one-way transmission, the separate resetting spring and the prestressing spring,
d) the positioning device and positioning pawls are one structural part, relinquishment of the separate positioning pawls and of a prestressing spring,
e) the positioning device with positioning pawls and the actuating button with a resetting element or combinations of these components form one structural part, relinquishment of the prestressing spring, of the separate actuating button and of the separate resetting element,
f) combination of the wind-on component into a wind-on module and of the positioning component into a positioning module, simplification of assembly.
In a preferred exemplary embodiment of the invention relating to a), the resetting spring, which returns the shift element, designed as a shift lever, into its initial position after actuation has taken place, is not tensioned between the housing or carrier part and the shift lever, as is customary, but is articulated on the housing and on the one-way transmission element. By virtue of this inventive arrangement of the resetting spring, on the one hand, the one-way transmission element in the form of a pivotable detent pawl is always prestressed in the direction of the toothed contour which is formed on the rotary element or on the wind-on reel and, on the other hand, the resetting of the shift lever is brought about. The detent pawl pivots about an axis which is connected fixedly to the shift lever and is prestressed against the sawtooth contour at the rotary element by the resetting spring which is articulated between the center of rotation and the pawl. As a result of this spring articulation, the additional prestressing spring otherwise required becomes superfluous and may be dispensed with. The prestressing force acting on the detent pawl is influenced, on the one hand, by the magnitude and direction of the spring force of the spring element and, on the other hand, by the position of the point of articulation or by the effective lever arm. This point of articulation for the resetting spring is, of course, selected on the detent pawl such that the latter is prestressed in the direction of the toothed contour, and is located on a radius emanating from the center of rotation of the shift lever, between the toothed contour of the wind-on reel and the center of rotation of the pawl. The arrangement of the point of articulation on the radius between the center of rotation of the detent pawl and the toothed contour makes it possible to vary the effective prestressing force from zero, when the spring force passes through the center of rotation of the pawl, to maximum, when the spring force acts on as small a radius as possible, for example approximately that of the toothed contour.
As is customary in ratchet mechanisms, in particular, in switches for bicycle gear shifts, a distinction is made between the actuation of the shift assembly in the wind-on direction, the holding of the wind-on reel in a selected shift position and the release of the shift assembly, which is under spring prestress, in the unwinding direction.
For winding on the shift assembly, essentially one actuating element in the form of a shift lever, one or more one-way transmission elements in the form of detent pawls and one wind-on reel provided with one or more toothed contours are required, which are arranged in a housing or a carrier part. Moreover, normally, a resetting spring ensures the resetting of the shift lever into the initial position and one or more prestressing springs ensure a reliable engagement of the one-way transmission elements into the sawtooth contour on the wind-on reel.
In an exemplary embodiment according to the invention which relates to b), one-way force transmission to the wind-on reel takes place by means of one or more one-way transmission elements which are prestressed radially and which form with the shift lever a structural part. A reliable space-saving and weight-saving transmission of shift force from the shift lever to the wind-on reel thereby becomes possible.
Since the one-way transmission elements are already prestressed in the radial direction and form with the shift lever a structural part, this inventive version dispenses, on the one hand, with the prestressing spring otherwise required and with the complicated assembly of the detent pawl, thus leading to the structural parts being minimized.
In the initial position, when the shift lever is not actuated, the one-way transmission element or one-way transmission elements are supported on the housing or carrier part, so that there is no engagement into the toothed contour of the wind-on reel. These one-way transmission elements have an elongate shape and are articulated on the shift lever on one side. They have, in the end region, a toothed or pawl shape suitable for engagement into the sawtooth contour of the wind-on reel and for the take-up of the latter.
These one-way transmission elements
Bonck Rodney H.
Cohen & Pontani, Lieberman & Pavane
SRAM Deutschland GmbH
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