Machine element or mechanism – Control lever and linkage systems – Multiple controlled elements
Reexamination Certificate
2000-04-20
2001-11-20
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Multiple controlled elements
C074S473360
Reexamination Certificate
active
06318205
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the priority of German Patent Application, Serial No. 199 19 269.3, filed Apr. 28, 1999, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates, in general, to a shift device of a change-speed gearbox of motor vehicles.
A change-speed gearbox has an input shaft and coaxial thereto an output shaft, as well as a countershaft in parallel disposition thereto. Shift rockers are used in the change-speed gearbox to axially displace shift sleeves that interact with gear wheel clutches for optionally coupling either the input shaft with the output shaft or the countershaft, whereby a locking device locks non-activated shift rockers via respectively connected locking rods.
U.S. Pat. No. 5,802,916, issued on Sep. 8, 1998, describes a shift device in which the locking device is operatively connected to the shift rocker by a locking rod in the form of a lever made from flat steel strip or flat iron. The locking lever is swingably mounted to a bracket of the shift rocker, whereby the bracket is a separate component which is formed integrally with the shift rocker and directed radially outwards. The securement of the locking lever to the bracket is implemented by a screws or rivets at a clearance to permit a swingable disposition of the locking lever. The need for many components to realize operation and function of the locking lever is a drawback of this conventional shift device for many reasons. The bracket is formed integrally with the shift rocker through a material-linking process such as welding which results in undesired local heat introduction that adversely affects the configuration and strength of the shift rocker. Moreover, the hinged attachment of the locking lever to the bracket by means of screws, rivets or bolts, requires an effective permanent securement.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide an improved locking lever for a locking device, obviating the afore-stated drawbacks.
In particular, it is an object of the present invention to provide an improved locking lever for a locking device, which is implemented by a reduced number of components and yet is reliably and permanently secured to the shift rocker.
These objects, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing a plurality of shift rockers rotatable between an activated position and a non-activated position, with each shift rocker being supported in a pivot bearing and activated through operation of a shift finger, which is fixedly mounted on a shift shaft, for axially displacing shift sleeves; a locking unit; and a plurality of locking levers operatively connecting the locking unit to the shift rockers and so operated as to lock the non-activated shift rockers, each said locking lever having one end exhibiting a curved configuration and terminating in a cylindrical pin for engagement in a recess of the associated shift rocker, with the cylindrical pin being held in place within the recess by impressing surrounding boundary regions of the shift rocker.
In accordance with a preferred embodiment of the present invention, the cylindrical pin may be press-fitted in the locking lever to thereby, in effect, form with the locking lever a structural unit. The locking lever is thus directly secured to the shift rocker so that the need for a separate bracket and a separate screw connection for attaching the locking lever to the bracket are no longer needed, thereby reducing the number of components. The recess in the shift rocker for receiving the locking lever and the cylindrical pin can suitably be made during manufacture of the shift rocker, thereby eliminating the need for a separate production step or a separate chucking. No longer is there any requirement for separate welding processes so that problems associated with welding as a consequence of local heating are not an issue. As the installation is simplified in view of the reduced number of components, the overall shift device is noticeably more cost-efficient. Effectively, the one-piece configuration of the locking lever and the cylindrical pin is inserted, in accordance with the invention, in the recess before impressing the boundary region around the recess for securing the cylindrical pin in place. These assembly steps may be automated for cost-savings reasons. The securement of the locking lever in accordance with the present invention results further in an increased shear strength as a consequence of a double-section connection, realized by projecting portions of the cylindrical pin on both sides of the locking lever.
According to another feature of the present invention, the cylindrical pin is received with play in the recess of the shift rocker to permit a swinging motion of the locking lever, and the impressions for securing the cylindrical pin in place are so implemented as to enable an unhindered rotation. However, it is also possible, as an alternative, to receive the cylindrical pin in fixed rotative engagement in the recess while inserting the cylindrical pin with play in a bore of the locking lever.
According to another feature of the present invention, the cylindrical pin is so inserted in a bore of the locking lever and held in position as to project from the locking lever on both sides at a same distance. In this manner, the cylindrical pin is operatively securely coupled to the locking lever and a tilting of the locking lever is prevented.
According to another feature of the present invention, the cylindrical pin may be a needle-shaped rolling element for insertion in the locking lever. This type of cylindrical pin can be made on a large scale in a cost-efficient manner at high accuracy and strength for combination with the locking lever.
Suitably, the recess is configured as an opening which traverses the shift rocker for insertion of the end region of the locking lever. Extending from both sides of the opening are sections of the recess of limited depth for receiving the ends of the cylindrical pin projecting out from both sides of the locking lever. This configuration of the recess simplifies the assembly because the locking lever is positioned by the cylindrical pin in this assembly position, when the locking lever is inserted in the recess, and it is only required to impress opposite boundary regions surrounding the recess.
According to another feature of the present invention, the recess may also be configured as an opening extending over the entire length of the cylindrical pin and made in a cost-efficient manner by punching through the shift rocker. The locking lever can be positioned in place in such a recess by providing several impressions, i.e. impressions on both sides of the opposite boundary regions. Suitably, after stamping the recess, the boundary regions may be impressed on the shift sleeve confronting side of the shift rocker. In this manner, the locking lever is oriented in place already when inserted in the recess and requires only a further impression of the boundary regions on the opposite side of the shift rocker for positioning the locking lever in place.
Suitably, the recess in the shift rocker and the attachment of the cylindrical pin are so configured that the locking lever is swingable at least about an angle of ≧10°.
REFERENCES:
patent: H295 (1987-07-01), Numazawa et al.
patent: 5471893 (1995-12-01), Newbigging
patent: 5802916 (1998-09-01), Ebinger et al.
patent: 6038938 (2000-03-01), Szczepanski et al.
patent: 6122983 (2000-09-01), Hoffman
patent: PS 9 41 713 (1955-10-01), None
patent: 24 56 962 A1 (1975-06-01), None
patent: 196 09 210 C1 (1997-07-01), None
Kramer Klaus
Steinberger Wolfgang
Trissler Arnold
Feiereisen Henry M.
Fenstermacher David
Ina Walzlager Schaeffler OHG
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