I suspect that who ever wrote this article is too young to remember vacuum operated windshield wipers. I suppose the first mechanical wiper was electrically driven but the vacuum wiper would have been less costly and would have very quickly replaced it. Since it ran from the vacuum produced in the intake manifold the wiper stopped moving during acceleration. We had a 1931 Chevy with vacuum wipers, a 1937 Ford with vacuum wipers, a 1940 Chrysler with electric wipers, note: luxury car, and a 1953 Ford with vacuum wipers. I don't know when electric wipers moved down to Fords, Plimiths, and Chevys, but it was probably different years for every brand.
Regards. Max. K 4 O D S. Email: [EMAIL PROTECTED] Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, [EMAIL PROTECTED] ----- Original Message ----- From: "Ray Boyce" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, October 04, 2007 4:00 AM Subject: [BlindHandyMan] How is a windshield wiper made? > Background > > Windshield wipers are used to clean the > windshield > of a car so that the driver has an > unobstructed > view of the road. A typical > wipe > angle for a passenger car is about 67 degrees. The blades are 12-30 in > (30-76 cm) long with lengths increasing in 2-in (5-cm) increments. > > History > > The history of the windshield > wiper > began with the invention of the automobile. Most transportation vehicles > did > not have wipers. Horse-drawn carriages and trucks moved at slow speeds, > and > glass was not needed to protect the driver or passengers or to act as a > windbreak. > > The first windshield wipers were brushes. Inventor J. H. Apjohn came up > with > a method of moving two brushes up and down on a vertical plate glass > windshield > in 1903. In the same year, Mary Anderson devised a swinging arm that swept > rain off the windshield when the driver moved a > lever > located inside the car. Anderson patented her invention of the mechanical > windshield wiper in 1905, and it became standard equipment by 1913. > Electric > motors > were not used yet to power automobile essentials or accessories, and > Anderson's device had a > drawback. > Without another power source, a driver had to use one hand to move the > lever. The driver's other hand steered the car (with either a wheel or > steering > tiller) > and worked the stick-mounted gear shift and brake grips standing on the > floor of the car or outside the driver's side on the running board. > > Rubber strips replaced brushes as the cleaning tools on wipers in 1905. > Unfortunately, the hazardous need for drivers to wipe windshields while > driving > was not eliminated until 1917. The solution was to use an electric motor > to > move a single wiper with a long rubber blade back and forth. Hawaiian > dentist > Dr. Ormand Wall invented the automatic wiper by placing an electric motor > in > the top center of the windshield so the wiper arced down over the hood of > the car in a semi-circular or rainbow shape. Wipers were one of the first > electrical devices in automobiles after the electric starter was developed > in > 1912. Most wipers on cars before 1930 were paired and hung down from the > top > of the windshield. They were moved to the base of the windshield as > electrical > systems became more complicated. > > Windshield washers were added to the wiper on/off levers, and these > required > spray nozzles in front of the windshield, a tank for washer fluid in the > engine > compartment, > and electrical connections to coordinate these operations. In 1962, Bob > Kearns invented the > intermittent > wiper with intervals and speeds that the driver could change. The advent > of > electronic systems with fuses and > circuit breakers > to operate, regulate, and coordinate electrical components expanded the > possibilities for more diverse wipers. Wipers were added to headlights in > the 1980s, > requiring connections between the lighting and wiper systems. In the > 1990s, > microsensors were built into windshields to detect rain on the windshield, > activate the wipers, and adjust speed and intermittent use for the amount > of > rain. > > Raw Materials > > The manufacturer purchases all of the parts from companies that specialize > in fabricating parts from aluminum and steel, rubber blades, plastic > bushings > for the linkages, and the motors. Windshield wipers and windshield wiper > systems (with motors) are different assemblies; some manufacturers make > both, > and others produce wipers only. > > The connecting and drive links and the pivots that move the wipers are > made > of > galvanized > steel. Galvanization is the process of applying > zinc > coating to steel to protect it from > corrosion. > Drive arms for boats and vehicles used in the marine industry are made of > stainless steel that resists damage from salt water. The wiper suspension > and > claws are also galvanized steel. The galvanizing zinc coating is easier to > paint than uncoated steel. Steel is also the material in the small parts > of > wipers, such as washers, screws, nuts, springs, and > brackets. > > The blade frame is made from aluminum. The blades are made of natural > rubber > or synthetic compounds. Some rubber blades are composites of soft rubber > on > the wiping edge (the > squeegee > surface) and firm rubber that supports the wiping edge in the rest of the > blade. > > Other materials that comprise parts of windshield wipers are rubber for > washers in the pivots and plastic bushings that line holes for connecting > parts > of the > linkage. > The wiper suspension is typically painted black. If the wiper manufacturer > also builds wiper systems, motors are purchased from subcontractors. The > motors > are contained in steel housings and include permanent magnet motors wound > with copper wire. Each housing has connections for the electrical wires > that > are part of the vehicle and wiring harnesses are furnished specific to > operating the wipers. Each motor also contains one or more electronic > circuits depending > on the sophistication of the system that the motor controls. > > Design > > Windshield wipers are designed and made to clear water from a windshield. > Most cars have two wipers on the windshield, and they may have one on the > rear > window and one on each > headlight. > The wiper parts visible from outside the car are the rubber blade, the > wiper > arm holding the blade, a spring linkage, and parts of the wiper pivots. > The > wiper itself has up to six parts called pressure points or claws that are > small arms under the wiper. The claws distribute pressure from the wiper > along > the back of the blade. This is described as a balance beam with a > suspension > system, where the wiper is the beam and the claws are the suspension > components. > The claws keep the blade > flexed > against the windshield to distribute even pressure to clean the glass all > along the blade. More claws usually distribute the pressure better and are > suited > to large or highly curved windshields. > > Although the rubber is the familiar part of the blade, the blade actually > includes a metal strip called a blade frame with a slot along the length > of > the > frame and replacement holes in the frame. The replacement holes provide > access for replacing the rubber blade with a > refill. > The blade on its aluminum frame can also be changed as a unit. > > The standard two windshield wipers are usually operated as a single-motor, > tandem scheme with one wiper on the driver's side and one positioned near > the > middle of the windshield that moves across the passenger's view. The > wipers > are secured to pivots. A wiper and > pivot > are mounted on brackets at both ends of a long rod called the connecting > link, and, as the force from the motor pushes on the driver's end of the > connecting > link, it in turn moves the other wiper. The connecting link is attached to > another long rod called the drive link near the wiper motor. A slender > spring > linkage ties the pivot to the drive link to return the wiper to its > resting > or park position, > hug > the wiper close to the windshield, and keep it attached to the car if the > links are damaged. > > Between the motor and the drive link, a linkage system consisting of a cam > (another short rod) and pivot, a gear output shaft, and a worm gear > controls > the force of the motor delivered to the drive arm. The worm gear slows the > speed of the motor while > multiplying > its > torque > (force). The gear allows a small motor to produce enough force to move the > blades across the glass. This description is based on using a single motor > to > drive both wipers. If one motor powers each wiper, more links are needed > to > move the two wipers together in a so-called unitized motor system. > > This multiplied force is required to accelerate the blades from being > stopped at both ends of their movement, to resist the friction of the > rubber > against > the glass, to resist the friction of the rubber on dirt on the glass, and > to > oppose wind pressure on the windshield. > > The tandem scheme is the most common because the blades produce > overlapping > cleared areas on the windshield with the greatest overlap in front of the > driver. > An opposed scheme with two blades begins with both blades on the > windshield > toward the sides of the car, and the blades overlap as they both pivot > toward > the center of the windshield. A single wiper that swings in an arc from > the > center of the windshield is also used. The single-arm controlled wiper is > the > most complex; as it sweeps over the glass, the wiper arm lengthens toward > the car sides and retracts again as it points straight up at the middle of > the > windshield. Each of the two wipers in the tandem and opposed operating > schemes and the one wiper in the single-wiper scheme make an arc with a > single radius > and so are called radial arm wipers. The single-arm-controlled wiper > produces a multiple-radius arc. > > The electric motor, worm gear, gear shaft, cam, drive link, and pivots are > built into the > underside > of the dash. The connecting link and wiper pivots are located below the > windshield and behind the trim molding. Wipers called depressed wipers > also > rest > behind the molding when they are not being used. Non-depressed wipers are > above the windshield trim molding even at rest and are visible from > outside > the > car and from the passenger compartment. In the passenger compartment, the > wiper's on/off lever is usually attached to the steering column. When the > wipers > are turned on, an electronic circuit inside the wiper motor starts it. > When > the wipers are turned off the circuit stops the power to the wiper motor. > Intermittent > operation of the wipers is basically short on-and-off periods for the > wiper > motor that the circuit also regulates. > > The Manufacturing > Process > 1. Wiper manufacturers carry large stocks of materials provided by > subcontractors. As the materials are received, the receiving inspectors > confirm that > the types and quantities of parts are correct, compile an inventory, and > store the parts. > 2. The worker begins by putting together the pivot shaft for each wiper. > The > pivot shaft is made of a set of > fasteners > and spacers that hold the wiper arm securely while allowing it to pivot > and > sweep the design wipe angle. The shaft assembly includes the pivot shaft > itself > and (from the end near the small connecting link to the tip of the shaft) > a > rubber washer, metal washer, nut, nut cap, knurled driver, washer, and > acorn > nut. The knurled driver is a type of nut with ridges on the sides that > grip > any attachment. The wiper arm will sit on the knurled driver, which keeps > it > from shifting out of position on the shaft, and the washer and acorn nut > hold the arm on the shaft. The pivot shaft is then attached to the small > connecting > link with a washer and spring clip. A pin on the pivot shaft can be > inserted > in any one of three pin positions when the shaft is attached to the link, > depending on the design for the pivot and link. > 3. For a single-arm wiper scheme, a U-shaped, galvanized steel bracket is > fixed to the small connecting link on the only pivot shaft with two shaft > screws. > The other end of the bracket will be attached to the drive link later. For > a > scheme with two wipers, the small connecting link for the wiper on the > passenger's > side is joined with a bracket to the end of the longer connecting link > with > shaft screws. Similarly, a bracket is put on the small connecting link for > the driver's side wiper, and it is attached to the opposite end of the > longer connecting link. Later, this end will also be attached to the drive > link. > 4. The drive link will be attached to the motor in the next step. The > motor > with the worm gear reduction and other linkage is a stock item provided by > a > vendor, and the wiper system manufacturer does not make any changes to it. > The drive link must be secured precisely on the cam (drive arm) on the end > of > the gear shaft so the wiper will sweep correctly but also so it can be > parked in the right position under the car molding. The connection between > the cam > and the drive link will be fixed by using another bracket called the > mirror > bracket. > 5. To set the angle between the drive link and the cam and motor, the > motor, > cam, mirror bracket, and drive link are put inside a die set. The die set > is > an outline-like pattern made of steel with areas fitted for the four > parts. > Wiper system makers have a collection of die sets with various angles for > mounting > the drive link to the motor. The bracket is put on the drive link with a > set > of screws. The bracket is then attached to the cam. > 6. With the angle established, the cam is checked for fit with the drive > shaft. Spacer washers are added (if needed) between the cam and drive > shaft, > and > the two are connected with a set of motor nuts and screws. For a > single-wiper scheme, the bracket with the single small link and pivot is > screwed on the > drive link. For a scheme with two wipers, the bracket on the end of the > long > connecting link that also supports the driver's side pivot and small > connecting > link is fastened to the drive link. > 7. In the final steps in assembling the windshield wiper system, linkages > made of springs are added to connect each pivot shaft to the drive link. > The > wiper > arms and blades are connected to the pivots. The starter on the motor is > also moved into the park position, and the wipers are placed in their park > positions. > 8. If the customer is purchasing windshield wiper systems, accessories may > be included. A system of washers with water bottles, tubing, and controls > for > the dash is the most common accessory set. A wiring > harness > with the washer controls and the other electrical connections for the > wipers > is provided with the motor. > 9. The completed windshield wipers are given a final quality control > inspection as described below and transferred to the packing area. > Depending > on the > items ordered, each set consisting of wipers, a motor system, and > accessories is boxed with operating, maintenance, and return information. > > The separate boxes are bundled together and packed in shipping cartons if > the customer ordered several items. > > Quality Control > > During assembly, the workers observe the conditions of the parts during > their work, but their only specific quality control activity is to check > the > operation > of the motors by turning them on to make sure they start and by listening > to > the sounds they make as indications of performance. > > The last inspection is performed when the assemblies are complete and > before > the wipers and systems are packed. The manufacturing director or final > quality > control inspectors look at the general appearance of the assemblies, > confirm > that the wipers have been sized and angled correctly for their sweep, and > check that the assemblies are in the park position. The director or > inspectors also check to see that the correct accessories are ready to be > packed with > the assemblies. > > Byproducts/Waste > > Small quantities of steel and aluminum scraps from trimmings or rejected > or > damaged parts are collected in bins and sold to > salvage > dealers who, in turn, sell them to metal manufacturers who melt the scrap > down for > recycling. > Packaging from received parts is also collected and recycled. > > The Future > > As of 2002, windshield wipers and wiper systems are evolving because of > changes in automobiles and other vehicles, technical improvements, and > consumer > demand. Wiper blades are as much as 30 in (76 cm) long, creating more > resistance as they clean the windshield. Night-vision screens for > windshields are > in development, and these also increase resistance and change the > dimensions > needed for wipers. Blades are being improved with increasingly flexible > rubber, > so-called "boots" that fit around the blades to keep out ice and snow, and > nonstick coatings on the squeegee edges of the blades to keep oil and wax > from > adhering and aging them. > > Motor systems are also being increased in voltage to power longer wipers > and > more accessories. Engineers are investigating fully automated systems that > do not require any actions by drivers to start and stop wiper systems. > Inventors expect the capabilities of the rain-detecting sensors available > in > the > late 1990s to > widen > to prompt the wipers to clean dirty windshields with no rain, for example. > Windshield wipers are among most reliable automotive devices-the design > life > of a wiper system is 1.5 million wipes. > > > > To listen to the show archives go to link > http://acbradio.org/handyman.html > or > ftp://ftp.acbradio.org/acbradio-archives/handyman/ > > The Pod Cast address for the Blind Handy Man Show is. > http://www.acbradio.org/news/xml/podcast.php?pgm=saturday > > Visit The Blind Handy Man Files Page To Review Contributions From Various > List Members At The Following address: > http://www.jaws-users.com/handyman/ > > Visit the archives page at the following address > http://www.mail-archive.com/[email protected]/ > > If you would like to join the Blind Computing list, then visit the > following address for more information: > http://jaws-users.com/mailman/listinfo/blind-computing_jaws-users.com > > For a complete list of email commands pertaining to the Blind Handy Man > list just send a blank message to: > [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.488 / Virus Database: 269.13.36/1041 - Release Date: > 10/1/2007 10:20 AM > >
