FAQs: Engineering Analysis
Effective Analysis of a SHAKER™ on a Wiper Arm/Blade/Linkage/Transmission
The following excerpts come from a report of the same name created by CA Elliott Inc. Design & Manufacturing Services ("www.caelliot.com"). For a full copy of this report, please contact "info@wipershaker.com".
Conclusion
"The SHAKER™ increased the weight of a wiper assembly (e.g. arm, spring etc.) with a 21” blade by approximately 18%, which translated to an ice build-up equivalent on the wiper assembly of approximately 2mm (0.08 inches).
With the addition of the SHAKER™ , an average wiper motor can be expected to operate at 25% or less of the motor's stall current under normal operating conditions, an increase of only 4 to 5% of the allowable current operating range.
Based on the above analysis with the constraints provided, it can be concluded that the additional weight of the SHAKER™ will not have a negative long-term impact on the performance or life span of a wiper assembly.
The increased wiper assembly weight is comparable to an equivalent build up of freezing rain, a common occurrence in northern climates. Alternately, the SHAKER™ weight could be compared to the additional weight a wiper assembly might see from a heavier winter wiper blade.
The wiper assembly with SHAKER™ continues to operate well within the normal current operating range of the motor, and significantly below the stall current. Wiper motors are designed to withstand a stall force caused by severe ice build-up or blockage, as are the mechanical linkages and gears. With generous automotive safety factors in place, the wiper assembly is capable of handling large loads before failure occurs (as shown in figure 4).
Further in-field testing was performed by Wiper Shaker Technology Inc. to investigate the impact of the SHAKER™ on the range of travel of a wiper assembly. The test results indicated no noticeable over-sweep on the wiper system, even with a frictionless set-up. This physical test further reinforces that the SHAKER™ does not contribute significant loading to the wiper assembly.
The SHAKER™ weight was related to an analogy of ice build-up on the wiper assembly. It was assumed that ice builds up on the top and side surfaces of the wiper assembly. As shown in Table 1, the addition of the SHAKER™ weight is equivalent to approximately 2mm of ice build-up on a 21” wiper assembly.
Alternately, the addition of the SHAKER™ weight is comparable to a heavier winter wiper blade, which can easily add 50 to 100 grams of weight per blade.
The SHAKER™ weight further relates to the resultant torque applied to the wiper motor. Three scenarios were investigated. The first scenario was a no load condition, applying the wiper assembly weight with and without the SHAKER™ . The second scenario included the friction of the blade sliding on a dry windshield. The final scenario substituted the dry windshield with a wet windshield."
Figure 4.
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