Stroke-controlled windshield wiper unit for motor vehicles

A stroke-controlled windshield wiper unit having a gear casing, screw-connected rotationally solidly to a drive unit which can be mounted on the vehicle independently of the drive shaft by a drive shaft rotationally solidly connected to a stroke mechanism of the wiper. The drive shaft is designed as a hollow shaft which accepts a threaded bolt passing through it. The head of the threaded bolt is located at the gear casing end to allow assembly to previously installed windshield.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates generally to a stroke-controlled windshield wiper 
unit for motor vehicle and more specifically to a wiper unit having a gear 
casing, including a stroke mechanism of the wipers which is rotationally 
solidly screw connected to a drive unit by a drive shaft rotationally 
solidly connected to the stroke mechanism of the wiper. 
A windshield wiper unit of this type is shown in German Patent 
Specification No. 2,417,128. In this case, the gear casing is mounted to 
the drive unit before mounting to the vehicle. 
The fitting of such a windsheld wiper unit can involve difficulties if the 
drive unit has to be fitted into the vehicle first and the gear casing is 
only fitted subsequently. Under certain circumstances, the internal screw 
connection of the gear housing and drive shaft to the drive unit cannot be 
reached or can only be reached with difficulty. 
Thus, it is an object of the present invention to provide a windshield 
wiper unit wherein the gear casing can also be fitted directly as the 
conclusion of an assembly operation. Another object is to provide a 
windshield wiper unit that allows fitting and removal without difficulty 
in cases where a vehicle windshield has already been installed. 
These and other objects are achieved in accordance with the invention with 
the drive shaft being a hollow shaft which accepts a threaded bolt passing 
through it, the head of which bolt being located at the gear casing head. 
The drive shaft and the drive unit have intermeshing splines to form the 
solid rotational connection. Means are provided for limiting axial 
displacement of the drive unit when it is being screwed to the gear casing 
by the bolt. A hexagon socket is provided in the head of the bolt. Thus, 
the gear casing, stroke mechanism and drive shaft may be fitted to the 
drive unit easily at any stage of installation. 
Other objects, advantages and novel features of the present invention will 
become apparent from the following detailed description of the invention 
when considered in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS 
A drive unit 2, including a drive motor which is not shown, is fastened to 
the vehicle via a base plate 1. The windshield 3 with a lower seal 4 may 
be also fitted to the baseplate 1 at this time. 
A gear casing 5 with a drive shaft rotationally solidly connected thereto 
and an adaptor 7 are then introduced as a preassembled unit into the drive 
unit 2. The gear casing 5 and drive shaft 6 in the embodiment shown are 
designed as one piece. The drive shaft 6 is designed as a hollow shaft and 
accepts a threaded bolt 8, which is introduced from the gear casing end of 
the assembly. A head 9 of bolt 8 has a hexagon socket. A connecting rod 10 
of the stroke mechanism is supported in the gear casing 5 after insertion 
of the bolt 8 in drive shaft 6. The hole in connecting rod 10 is used 
later for inserting a hexagon socket key 12 into the hexagon socket of 
bolt 8. 
The drive shaft 6 has splines 13 at its free end which interact with mating 
splines 14 on the drive unit 2 to form a solid rotational connection. 
Using a hexagonal socket key 12, threaded bolt 8 is screwed into drive unit 
2. Thus, the gear casing 5 is rotationally solidly connected to the drive 
unit 2 by the threaded bolt 8 and mating splines 13 and 14. Attention is 
given to ensure that the drive unit 2 is located by toes 15, 16 in such a 
position that they limit axial displacement of the drive unit 2 during the 
screwing operation. 
The fixed or non-rotational adaptor 7 and the base plate 1 can be 
subsequently connected by screws 17. 
Finally, it should be noted that it is only possible to introduce the 
hexagon socket key 12 through hole 11 and into head 9 at a particular 
position of the connection rod 10. This assures that the connecting rod 
10, drive shaft 6 and drive unit 2 have a specific angular relationship 
before the splines 13 and 14 mate. Thus, incorrect fitting which would 
otherwise be possible, if avoided. 
In order to conclude the fitting procedure, the gear casing is closed by a 
clip-on cap 18. 
Since the bolt 8 is accessible and manipulated from the gear casing side of 
the assemble, the gear casing, stroke mechanism and drive shaft may be 
aligned, fitted and assembled to the drive unit at any stage of assembly 
of the unit and its mounting to the vehicle. 
Although the present invention has been described and illustrated in 
detail, it is to be clearly understood that the same is by way of 
illustration and example only, and is not to be taken by way of 
limitation. The spirit and scope of the present invention are to be 
limited only by the terms of the appended claims.