Wiper blade for windshields, especially automobile windshields, and method for the production thereof

• US 6,836,926 B1
• Filed: 07/06/2000
• Issued: 01/04/2005
• Est. Priority Date: 07/09/1999
• Status: Expired due to Term

• Current Assignee: Robert Bosch LLC (Robert Bosch GmbH)
• Original Assignee: Robert Bosch GmbH
• Inventors: De Block, Peter
• Primary Examiner(s): Warden, Sr., Robert J.
• Assistant Examiner(s): GUIDOTTI, LAURA COLE
• Application Number:
  US09/786,852
• Time in Patent Office: 1,643 Days
• Field of Search: 152/504.3, 152/504.4, 152/504.51, 152/504.8, 152/503.61, 152/502.02, 152/503.3
• US Class Current: 15/250.43
• CPC Class Codes: B60S 1/38 Wiper blades provided with liquid spreading means B60S1/524; provided with gas spreading means B60S1/546
• CPC Class Codes: B60S 1/3874 with a reinforcing vertebra
• CPC Class Codes: B60S 1/3875 rectangular section

Abstract

The invention relates to a wiper blade for windshields, especially automobile windshields, comprising at least one support element, a support element (12), a wiper strip (14) and connecting means (16) for a wiper arm (18). The support element (12) is a long flat rod to which the wiper strip (14) and the connecting means (16) are fixed. According to the invention, the flat rod has a cross-sectional profile (40), whereby F_wf*L²/48*E*I_zz<0.009 when F_wf is the pressure force exerted on the wiper blade or the pressure force for which the wiper blade was originally intended, L represents the length of the wiper blade, E stands for the elasticity module of the flat rod material and I_zz is the moment of inertia of the cross-sectional profile around the z axis (perpendicular to an s axis associated with the flat rod and perpendicular to the y axis).

Claims

1. A wiper blade for windows, comprising:

at least one support element (12), a wiper strip (14), and a connecting device (16) for a wiper arm (18), wherein the support element (12) is an elongated, flat bar to which the wiper strip (14) and the connecting device (16) are attached, wherein the support element (12) has a cross sectional profile in which $\frac{F_{\mathrm{wf}}*L^2}{48*E*I_{\mathrm{zz}}}<<br><br>0.009,$

where F_wf is an actual contact force exerted on the wiper blade by the wiper arm (18) in condition when it is pressed against a window, L is a length of the support element (12), E is an elasticity modulus of the support element (12), and I_zz is a moment of inertia of a cross sectional profile around a z-axis perpendicular to an taxis, which adapts along with the support element (12), and perpendicular to a y-axis, wherein the support element (12) has a substantially rectangular cross sectional profile (40), with a substantially constant width b and a substantially constant thickness d.

2. The wiper blade according to claim 1, wherein $\frac{F_{\mathrm{wd}}*L^2}{48*E*I_{\mathrm{zz}}}<$

0.005.

3. The wiper blade according to claim 1, wherein the support element (12) is comprised of at least two individual bars (42, 44) and wherein widths (b1, b2) of the individual bars (42, 44) add up to a total width b.

10. A method for producing a wiper blade assembly according to claim 1, comprising the following steps:

determining the length L and adapted contact force F_wf required for the window to be wiped,

determining a width b and a thickness d,

determining a curvature progression K(s),

bending the support element,

connecting the supporting element, wiper strip, and connecting device.

11. The method according to claim 10, comprising the following steps:

determining the length L and the cross sectional profile, particularly the width b and the thickness d by means of experimental values,

determining a contact force F_wf and a contact force distribution p for a flat window, which assures a favorable wiping quality, likewise by means of experimental values,

measuring the curvature progression K_window of the window,

double derivation of this curvature progression K_window of the window as a function of a coordinate that adapts along with the curvature,

calculating the second derivative of the curvature progression K(s) of the support element according to an above relation,

double integration yields a desired curvature progression K(s) of the support element.

4. A wiper blade for windows (15), comprising:

at least one elongated support element (12), a wiper strip (14), and a connecting device (16) for a wiper arm (18) which presses the wiper blade (10) against the window (15) in an operating position, wherein the support element (12) is an elongated, flat bar to which the wiper strip (14) and the connecting device (16) are attached, and which has a curvature when it is not loaded by the wiper arm (18), wherein the curvature along a coordinate (s), which follows a longitudinal span of the support element (12), has values such that a second derivative of the curvature as a function of this coordinate (s) is essentially proportional to a contact force distribution p (s), which is produced when the wiper blade (10) is pressed against a flat window (15), and wherein the contact force distribution decreases toward at least one end, wherein the support element (12) has a substantially rectangular cross sectional profile (40), with a substantially constant width b and a substantially constant thickness d.

5. The wiper blade according to claim 4, wherein $\frac{d^{}}{}$

2⁢

K⁡

(s)ⅆ

s2=ⅆ

2⁢

M⁡

(s)ⅆ

s2*E*I=p⁡

(s)E*I

s=coordinate along the support element

K(s)=curvature of the support element

M(s)=bending moment

E=elasticity modulus

I=surface moment of inertia of the support element in relation to a neutral axis

p(s)=specific force per unit length=contact force distribution.

6. A wiper blade for windows (15), comprising:

at last one elongated support element (12), a wiper strip (14), and a connecting device (16) for a wiper arm (18) which presses the wiper blade (10) against the window (15) in an operating position, wherein the support element (12) is an elongated, flat bar to which the wiper strip (14) and the connecting device (16) are attached, and which has a curvature when it is not loaded by the wiper arm (18), wherein the curvature along a coordinate (s), which follows a longitudinal span of the support element (12), has values such that a second derivative of the curvature as a function of this coordinate (s) minus the second derivative of the curvature of the window (15) decreases from a middle region (40) toward end regions, wherein the support element (12) has a substantially rectangular cross sectional profile (40), with a substantially constant width b and a substantially constant thickness d.

7. The wiper blade according to claim 6, wherein the middle region (40) is a location of the connecting device (16).

8. The wiper blade according to claim 6, wherein $\frac{d^{}}{}$

2⁢

K⁡

(s)ⅆ

s2=p⁡

(s)E*I+ⅆ

2⁢

Kwindow⁡

(s)ⅆ

s2

s=coordinate along the support element

K(s)=curvature of the support element

M(s)=bending moment

E elasticity modulus

I=surface moment of inertia of the support element in relation to a neutral axis

p(s)=specific force per unit length=contact force distribution.

9. A wiper blade for windows (15), comprising:

at least one elongated support element (12), a wiper strip (14), and a connecting device (16) for a wiper arm (18) which presses the wiper blade (10) against the window (15) in an operating position, wherein the support element (12) is an elongated, flat bar to which the wiper strip (14) and the connecting device (16) are attached, and which has a curvature when it is not loaded by the wiper arm (18), wherein the curvature along a coordinate (s), which follows a longitudinal span of the support element (12), has values such that a contact force distribution p(s), which prevails when the wiper blade (10) is pressed against a flat window (15) is greater in a region (40) approximately halfway between a center and an end of the wiper blade (10) than it is at the end of the wiper blade (10), wherein the support element (12) has a substantially rectangular cross sectional profile (40), with a substantially constant width b and a substantially constant thickness d.