WIPER ARM OF WINDSHIELD WIPER

Abstract: A wiper arm device includes a rotatable arm head (1) connected to a wiper motor, a retainer (6) rockingly connected to the arm head through a hinge pin (4), a spring (7) with one end (7A) being connected to the retainer and the other end being connected to a roller pin (9), and a link (10) supporting the roller pin and being rockable around a pivot shaft (5) which is mounted on the arm head. The link (10) can forcibly be displaced in response to the movement of the wiper arm from the rock-back condition toward the normal operating condition.

Description: Field of the Invention The present invention relates to a windshield wiper for use in a vehicle such as an automobile and, particularly, to a wiper arm of the windshield wiper which enables to take a rock-back condition. Description of Prior Art Various proposals have been made for enabling a wiper arm to take so-called rock-back condition whereat a wiperblade connected to the wiper arm is lifted up to separate from a windshield glass so that the blade rubber of the wiperblade can be protected from sticking to the windshield glass during a long period of non-usage and the wiperblade of the wiper or the windshield glass can be cleaned manually A typical prior art device is shown in Fig. 7, which comprises a rotatable arm head 1 connected to a wiper motor (not shown) through a pivot shaft 2 and secured thereto by a nut 3, a retainer 6 rockingly connected to the arm head 1 through a hinge pin 4 and supporting a wiperblade (not shown) on the free end (the left end in the drawing) thereof, a spring 7 with one end 7A being connected to the retainer 6 and the other end 7B being connected to a roller pin 9 through a hook 8, and a link 10 supporting the roller pin 9 and being rockingly supported around a pivot shaft 5 which is secured to the arm head 1. When a straight line connecting the connecting portion 7A between the retainer 6 and the spring 7 with the roller pin 9 passes above the pivot shaft 5, the retainer 6 automatically takes the rock-back condition by the force of the spring 7 and, when the line passes below the pivot shaft 5, the retainer 6 is automatically released from the rock-back condition and is urged against the windshield by the force of the spring 7. The prior art device shown in Fig. 7 is simple in the construction and, is easy in taking into or being released from the rock-back condition, however, there is a problem in determining the critical angle between the normal and the rock-back conditions. Namely, the angle at the rock-back condition is usually large so as to easily take into or to be released from the rock-back condition, otherwise, it sometimes is not possible to be released from the rock-back condition. Further, the range of the neutral condition, where the wiper arm does not move either of the normal operating condition and the rock-back condition by the force of the spring, is sometimes expanded due to the abrasion or wear of parts and the like. Such a device is known from the prior art of US-A-2 736 053 in which a windshield wiper carrying arm comprises an arm head mounting an oscillating shaft and a retainer to which a wiper blade is connected for back and forth movement across the field of vision through a windshield, said retainer straddling said arm head and being pivotally connected to same by a pin, a spring disposed lengthwise within the chamber of the retainer, the outer end of the spring being anchored to a support fixed on the retainer, while the inner end of the spring is connected either directly or through a hook to a pin at the inner end of a link, the outer end of the link being pivotally connected to the arm head by a pivot shaft. The present invention has been made with respect to the circumstances aforementioned, and an object of the invention is to provide a wiper arm having a small rock-back angle, and which enables to release easily and reliably from the rock-back condition. Summary of the Invention According to the invention there is provided a windshield wiper carrying arm comprising an arm head mounting an oscillating shaft and a retainer to which a wiper blade is connected for back and forth movement across the field of vision through a windshield, said retainer straddling said arm head and being pivotally connected to same by a pin, a spring disposed lengthwise within the chamber of the retainer, the outer end of the spring being anchored to a support fixed on the retainer, while the inner end of the spring is connected either directly or through a hook to a pin at the inner end of a link, the outer end of the link being pivotally connected to the arm head by a pivot shaft (winshield wiper carrying arm of the type disclosed e.g. in US-A-2,736,053 and defined in the precharacterising portion of claim 1), characterised in that the arm head is provided with a means for engaging with the link and positively displacing the link for its position swung away from the windshield into its normal operative position as the windshield has to be wiped. Preferably, the means for displacing the link is a pin secured to the retainer and being displaceable in a groove formed in the arm head. According to the invention, the link can forcibly be displaced, thus, it is possible to set a relatively small rock-back angle and to be released reliably from the rock-back condition. Brief Description of the Drawings Further objects and effects of the invention will become apparent from the following detailed description in conjunction with the drawings, in which: Fig. 1 through Fig. 4 are longitudinal sectional views showing various operating conditions of a wiper arm device according to a preferred embodiment of the present invention; Fig. 1 shows the normal operating condition; Fig. 2 shows the condition just before displacing into the rock-back condition; Fig. 3 shows the rock-back condition; Fig.4 shows the condition just before being released from the rock-back condition; Fig. 5 shows a cross-sectional view taken along line A-A in Fig. 1; Fig.6 shows a cross-sectional view taken along line B-B in Fig. 4, and Fig.7 is a longitudinal sectional view of a wiper arm device of the prior art. Detailed Description of Preferred Embodiments In Fig. 1 through Fig. 6, the parts corresponding to those shown in Fig. 7 of the prior art are depicted by the same reference numerals. In the normal operating condition, the wiper arm takes the condition of Fig. 1. And Fig. 2 shows the condition just prior to transfer into the rock-back condition, at which, a straight line connecting the end 7A of the spring 7 with the roller pin 9 passes through the pivot shaft 5. When the wiper arm is lifted from the condition of Fig. 2 by a small amount, the link 10 rotates in the counterclockwise direction around the pivot shaft 5 by the force of the spring 7 so that the roller pin 9 moves upward and the wiper arm takes the rock-back condition as shown in Fig. 3. For displacing the wiper arm from the rock-back condition of Fig. 3 to the normal condition of Fig. 1, there is provided a pin 12 which is secured to the retainer 6 and is movable in a groove 13 which, in turn, is formed in the arm head 1. In displacing the wiper arm from the rock-back condition of Fig. 3 to the normal operating condition of Fig. 1, the wiper arm or the retainer 6 is moved in the counterclockwise direction around the hinge pin 4 until the pin 12 engages with the link 10 as shown in Fig. 4. Upon further movement of the retainer 6, the link 10 is rotated in the clockwise direction, so that the straight line connecting the end 7A of the spring 7 with the roller pin 9 passes below the pivot shaft 5. The link 10 returns to the condition of Fig. 1 by the force of the spring 7, and the wiper arm returns to the normal operating condition of Fig. 1. Fig. 5 is a cross-sectional view in the normal condition of Fig. 1, and shows that the link 10 and the hook 8 are spaced from the pin 12. Fig.6 is a cross-sectional view showing transferring condition from the rock-back condition of Fig. 3 to the condition of Fig.4 and, it is clearly shown that the pin 12 is contacting with the link 10. In the embodiment, the transferring from the rock-back condition to the normal operating condition is performed by moving the retainer 6 in the counterclockwise direction from the condition of Fig. 3, then, the pin 12 forcively engages and presses down the link 10 as shown in Fig. 4. Then, the link 10 moves jumpingly to the condition of Fig. 1 by the force of the spring 7. However, the present invention is not limited to the embodiment and, it is possible to substitute the pin 12 by any other means which can forcibly move the link 10 from the condition of Fig. 3 to that of Fig. 1 in response to the movement of the retainer 6 from the condition of Fig. 3 toward that of Fig. 1. For example, an independent member may be secured to the retainer 6 to project toward the link 10, with the projecting end being spaced slightly from the link 10 in the rock-back condition, and which engages with and presses down the link 10 in response to the movement of the retainer 6 from the condition of Fig. 3 toward that of Fig. 1. As described heretofore in detail, the link according to the invention can forcibly be displaced from the rock-back condition toward the normal condition, thus, it is possible to set a relatively small rock-back angle, to release from the rock-back condition reliably, to simplify the construction and to reduce the cost.

Claims: A windshield wiper carrying arm comprising an arm head (1) mounting an oscillating shaft (2) and a retainer (6) to which a wiper blade is connected for back and forth movement across the field of vision through a windshield, said retainer (6) straddling said arm head (1) and being pivotally connected to same by a pin (4), a spring (7) disposed lengthwise within the chamber of the retainer (6), the outer end (7A) of the spring (7) being anchored to a support fixed on the retainer (6), while the inner end (7B) of the spring (7) is connected either directly or through a hook (8) to a pin (9) at the inner end of a link (10), the outer end of the link (10) being pivotally connected to the arm head (1) by a pivot shaft (5), characterised in that the arm head (1) is provided with a means (12) for engaging with the link (10) and positively displacing the link (10) for its position swung away from the windshield into its normal operative position as the windshield has to be wiped. A wiper arm device according to claim 1, wherein said means for displacing the link (10) is a pin (12) displaceable in a groove (13) formed in the arm head (1). A wiper arm device according to claim 2, wherein said pin (12) is secured to the retainer (6). A wiper arm device according to claim 1, wherein said means for displacing the link (10) is a member being secured to the retainer (6) and projecting toward the link (10) such that when the wiper arm takes the rock-back condition the member is spaced slightly from the link (10), and when the wiper arm returns to the normal operating condition said member engages with and moves down the link (10) forcibly in response to the movement of the retainer (6) toward the normal condition.

Inventors: ARAI, MASARU, SAITA, ITSURO
Applicants: NIPPON WIPERBLADE CO., LTD.
Application year: 1988
Main classification: B60S1
IPC codes: B60S1