The present invention is directed to a braking system for a vehicle manual window-lifting mechanism.
Most assembly specifications for window-operating handles specify a maximum free radial play in the shaft of the crank that drives the regulator for manual window opening on the order of 45° as a maximum, and often less than 30°. Most current manual control systems do not comply with this specification. Furthermore, current mechanisms allow the window to drop too quickly during irreversibility tests, very often beyond the specified limit.
Currently, the crank shaft and the cable-winding drum on which it is mounted with relative rotation are assisted by a helical spring that allows excessive free play in the crank shaft (on the order of 40° to 45°) before the drum is driven. The braking operation of the gearbox is realized in both directions of rotation of the crank shaft, that is, directions for both opening and closing of the window.
There is a desire for a system that can minimize free play in the crank shaft and prevents the window from dropping too quickly.
The invention is generally directed to a braking system for a vehicle manual window-lifting mechanism that prevents the window from dropping as a consequence of vibrations and minimizes angular play in the crank shaft.
To achieve the proposed advantageous effects according to one embodiment of the invention, the inventive structure includes a helical spring that assists the crank shaft and that has a geometry modified from its conventional design. The included angle between the radial side pieces with which the winding ends terminate is an acute angle. One of the side pieces is coupled inside a radial hollow of the crank-driven shaft itself. The other side piece is located between the crank shaft and the drum, which rotate relative to each other.
Several pages of drawings are attached to facilitate understanding of the characteristics of the invention, and these form an integral part of this descriptive statement. The figures are meant to be illustrative and not limiting in any way.
Referring to the Figures, the braking system for a vehicle manual window-lifting mechanism according to one embodiment of the invention includes a crank shaft 1 mounted coaxially with respect to a drum 2, these elements 1, and 2 being coaxially surrounded by a helical spring 3, such as a helical spring. An end 4 of a crank (not shown) connecting to the crank shaft 1 is splined along its length.
In position b), the crank shaft 1 rotates in an opposite, window-opening direction. The left radial side piece 5 of the helical spring 3 moves freely in the radial hollow slot 6 formed in one of the extensions 7 of crank shaft 1 and moves until it makes contact with the opposite side of the slot 6. The helical spring 3 is then compressed before the drum 2 can touch the right radial side piece 5 (i.e., minimum functional play), which would cause the system to brake.
In position c), when the drum 2 is driven directly in the window opening direction, the drum 2 contacts the right radial side piece 5 of the helical spring 3 due to expansion of the helical spring 3 before the crank shaft 1 can compress the helical spring 3 and cause the system to brake.
Finally, in position d) of
In other words, in position a) of
In position b), the crank shaft 1 has been driven and the helical spring 3 is compressed. The drum 2 moves counterclockwise, in the window-opening direction. Position c) shows when the drum 2 is driven. The helical spring 3 is extended, activating the braking function in the system. The drum 2 tries to move counterclockwise. Finally, in position d), the drum is driven, compressing the helical spring 3. The drum 2 conducts the crank shaft 1 clockwise.
In summary, the crank shaft 1 is engaged in positions a) and b) of FIG. 9. By contrast, the drum that is engaged in positions c) and d). As a result, instead of the usual 40° or 45° of free play, the acute angle in the winding ends of the helical spring allows a maximum free play of only 10° to 15° in the crank shaft. However, the inventive structure can be modified to allow or restrict free play over any desired range.
The braking operation, which is initiated by trying to lower the window manually via the drum, acts solely and only in the direction that is specified. This prevents the window from dropping due to causes other than manual operation (e.g., from irreversibility and from interruption or breakage), and in the meantime, the window can be raised manually. Thus, the inventive structure prevents the window from slowly descending on its own accord due to vibrations, bad roads, etc. During vibration and braking tests, window lowering due to free play of the system diminishes by about 50%. The inventive design also allows the crank-rotation drive system to function under reduced free driving torque (e.g., on the order of 0.2 Nm) and with very little free play in the crank shaft before driving the drum.
It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby.
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29723085 | Mar 1998 | DE |
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Number | Date | Country | |
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20040250473 A1 | Dec 2004 | US |