Brushing – scrubbing – and general cleaning – Attachments – Optical-member-attachable cleaner
Reexamination Certificate
1999-05-17
2001-05-22
Graham, Gary K. (Department: 1744)
Brushing, scrubbing, and general cleaning
Attachments
Optical-member-attachable cleaner
C015S250352
Reexamination Certificate
active
06233778
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is based on a wiper arm.
Known windshield wipers have a wiper arm which is constructed of a fastening element, secured to a drive shaft, that has a joint head; a joint part connected to the joint head via a toggle joint; and a wiper rod rigidly adjoining the joint part. The windshield wiper also has a wiper blade, which has a support bracket system and a wiper strip held by the support bracket system. The wiper blade is pivotably connected to the wiper arm in that a hooklike end of the wiper rod engages between two support cheeks of the support bracket system and surrounds a pivot pin. The joint thus formed guides the wiper blade with the wiper strip over a motor vehicle window; the joint part and the support bracket system make it possible for the wiper strip to adapt to a curvature of the vehicle window. A requisite contact pressure of the wiper strip on the vehicle window is attained with at least one tension spring, which braces the fastening element and the joint part jointly with the wiper rod via the toggle joint.
The fastening element is as a rule made from aluminum or die-cast zinc and is embodied as largely solid in its head and cone regions. A middle region of the fastening element has a U-shaped cross section, open toward the vehicle window, with reinforcing ribs.
To prevent the wiper arm in the preassembled state, before it is mounted on the motor vehicle, from collapsing in response to the spring force and thus to prevent the tension spring from coming unfastened, two side walls of the joint head extend in the longitudinal direction via the toggle joint and form two support faces, by way of which the joint part can be supported in the direction of the wiping area.
In known wiper arms, the fastening elements are often covered with a plastic cap that has a top wall and side walls, so as to protect the fastening element and its bearing points against soiling and corrosion and to obtain an attractively shaped component.
In order to make the cap in the hinged-open state secure against being lost and yet easily mountable and unmountable, the cap is pivotably supported on bearing faces that are closed over more than 180° on bearing protrusions on the joint head. The bearing faces are formed by the face ends of the side walls. If the fastening element or the wiper arm is to be mounted on the motor vehicle or unmounted or adjusted, the cap can be hinged open on the side of the bearing point for the drive shaft. Via the more than 180° closed bearing face, the cap is supported secure against being lost in the hinged-open state and can easily be slipped on by its open side or pulled off again.
To allow folding the cap open far enough, there is a recess in each of the side walls of the joint head that extend along the toggle joint; the cap can dip into this recess with its top wall when it is opened.
In the installed state on the motor vehicle, the tension spring generates the contact pressure of the wiper blade on the windshield. In the preassembled state, this force must be absorbed via a far shorter lever, from the toggle joint to the support face, and as a result a strong force acts on the support face. To allow securely absorbing this force in the joint head, the side walls must be made sufficiently high. In the region of the recesses, the cross section is weakened by the recesses and is more heavily loaded by notch stresses, which must be compensated for by a sufficiently high side wall below the recess. As a result, there are especially high side walls around the recesses.
Furthermore, the side walls of the joint head are made thicker than those of the remainder of the fastening element, so that the stresses around the toggle joint can be reliably absorbed. The greater material thickness, because of a uniform transition suitable for casting, extends up to the support faces.
ADVANTAGES OF THE INVENTION
According to the invention, the joint head has a round face end, and as a result with little expenditure of material, uniform wall thickness and thus a shape suitable for casting is attained for absorbing the stresses around the toggle joint. The joint head can be manufactured in a casting operation jointly with the fastening element or can be mounted afterward.
The face end of the joint head serves simultaneously as a guide for the cap. The bearing face at the cap is formed In keeping with these objects, one feature of present invention, resides, briefly stated, in a wiper arm which avoids the disadvantages of the prior art. over a first part of the angle by the face ends of the side walls of the cap, which are guided on bearing protrusions disposed laterally on the joint head. The remainder of the angle is formed by the inside of the preferably curved top wall of the cap, which is guided on the face end of the joint head. One support cheek is disposed on each side of the joint head and extends in the longitudinal direction, and its top side acts as a support face.
The top wall is embodied as narrower than the inside clearance between the support cheeks, so that the top wall can be thrust between the support cheeks when the cap is opened. Recesses in the support cheeks can be avoided as a result, and thus the support cheeks can be made triangular or in the form of truncated triangles in the longitudinal direction, with little expenditure of material, in a way that suits the course of the moment. The joint head can be made from little material and thus can be made light in weight. This makes the construction especially suitable for fastening elements or joint heads of zinc, so that despite the heavy yet economical material, an acceptable weight can be achieved.
Without recesses, the casting mold for the fastening element or the joint head also becomes simpler, because pushers or similar emplacement parts for the recesses can be dispensed with.
The construction according to the invention also assures that the bearing face on the cap, which overall encloses an angle of more than 180°, can be distributed over a plurality of planes, each encompassing less than 180°. As a result, the cap can be made in a casting process without pushers. The casting molds become narrower as a result, and thus more molds can be placed side by side. They are also less expensive, and the production cost becomes less.
In a further feature of the invention, it is proposed that the bearing protrusions on the joint head have a greater radius than the outer contour of the joint head. Given a favorable pivot point, the cap can be hinged upward by more than 90° (in the prior art, only about 60° was possible).
The strains can also be better absorbed by the entire width of the joint head, including the height of the bearing protrusions; that is, an axially larger effectively usable bearing face is created, which in particular is reinforced in its outer region by the large radius of the bearing protrusions. Over the service life, there is less bearing play. In addition, an attractively shaped cap can be formed that covers the fastening element except for the bearing protrusions and the support cheeks.
Further advantages will become apparent from the ensuing description of the drawing. The drawing shows one exemplary embodiment of the invention. The drawing, description and claims include numerous characteristics in combination. One skilled in the art will expediently consider each of the characteristics individually as well and combine them into appropriate additional combinations.
REFERENCES:
patent: 3800356 (1974-04-01), Ito
patent: 4472854 (1984-09-01), Bauer et al.
patent: 4856137 (1989-08-01), Palû
patent: 2326183 (1974-12-01), None
patent: 2511013 (1976-09-01), None
patent: 4128705 (1982-04-01), None
patent: 4408733 (1995-09-01), None
patent: 2543897 (1984-10-01), None
patent: 2550147 (1985-02-01), None
patent: 2607766 (1988-06-01), None
Graham Gary K.
Robert & Bosch GmbH
Striker Michael J.
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