Arizona republican., 1918-06-23
UNIVERSAL JOINT
 HARDEST WORKING
 PART IF AN AUTO

IHlII Ul Hll HUIU
 Here is one of the hardest working parts of the motor cars mechanism and yet many car owners are una ware of the existence of such a thing as universal joint. The name uni versal joint, or plain universal as it is generally shortened, accurately de- scribes the part. It is a joint so con- structed that it may move in any direction, sideways and up and down, at the same time that is revolving with the propeller. shaft.
 In the design of the modern car there is a propeller shaft, which car ries the drive to the rear axle. This is fitted with one or two universal joints, so that it may conform with the movements of the rear axle. If the propeller shaft were not so fitted, it would snap off the first time the rear axle bounced up and down with the action of the springs. The uni versals compensate for this movement of the aXcle.
 It doesn't take any great amount Of imagination that a part charged With function, or rather functions, Of this sort, ought to have a certain amount of care and attention. For such continuous movement as here takes place, the only alleviating con- dition is copious and consistent lubri- cation. Do the universals get this kind of treatment at the hands of the average owner? They do not; in fact most universals run most of the time without fabrication.
 In spite of the fact that the uni yersals will continue to function for long time even when they are con sistently neglected the running of the car will be improved if these parts are maintained as they should be. Most drivers have noticed a tendency on the part of the car to jerk. This may be caused in the main by badly worn universal joint and the wear is probably due to faulty fabrication.
 Difficult to Oil
 While. the universal joint is a re- markedly efficient bit of mechanism, in fact some makes are claimed to be 9S per cent efficient, it is fact that fabrication of the part is difficult at best. From the character of its move ment, the universal develops tend oncy to throw off the lubricant to the side. This is due to the centrifugal force that is present. Also the lubri- cant is likely to be squeezed out from between the rubbing surfaces, by req son of the twist or torque of the jornt.
 The universal joint of today differs considerably from it's forebears of q few years ago. The original univer- Cir orIx nf shaped piece, the ends of this acting as bearings for the U-shaped parts. With two of these, one moving up and down and the other sideways, universal action was obtained These primeval universals practically always ran exposed.
 After long experiment and improve ment. the engineers hit upon the ball | type of universal. This type embod ies a ball which rests in a socket, thus producing the universal move ment that is needed for the propeller shaft. Some of the present designs of universals provide not only for up and down and sideways movement, but for forward and back thrust as well. While this sliding joint idea has found considerable favor, most engineers prefer to provide for this front and back movement in other parts of the mechanism.
 Not Always of Metal Strange as it may seem, universal joints are not always made of metal. Within the past few years there have been introduced a number of fabric joints, leather joints and combinations of the two. The great advantage of this non metal type is that 1t can do without fabrication. Further, noise IS practically eliminated from the opera 1 tion of the part. In fact, the only care the fabric and leather joints re | quire is an inspection once month | or so and a tightening up of the re- 1 taining members as they happen to need it.
 The non-metal or flexible universal l joint cannot be employed with all constructions of mechanism, it's avail ability depending largely on the angle of operation of the propeller shaft. In constructions where the shaft is near ly level, the flexible joint is most de- sirable, and is warmly advocated by some designers. When the shaft IS placed at a great angle, the metal l joint is necessary, because it has a | greater radius of action. Flexible uni versals are used mainly where the transmission is located amidships and operate from the clutch and engine. | The universal is then placed between clutch and transmission.
 Single Piece of Leather
 Some of these fabric joints are made of a single piece of leather, while others embody a number of leather parts fastened together. There is a universal on the market today made up of several layers of a close woven cotton fabric, placed one on top of the other and each at different angle, so as to compensate for the pull at any given point and thus give uni form strength.
 There is little that the car owner is called upon to do to keep the universal joints in the best possible shape. Once ap month or oftener if experience shows it to be necessary the housing of the joint should be re- moved Sometimes the housing is ot metal and again it takes the form ol a leather boot.
 At any rate it should be taken of periodically and after the joint has been flushed out thoroughly witt kerosene it should be repaclled witt fresh grease. graphite or one of the non fluid lubricants sold for the pur- pose. oil would be the best lubri- cant for this part, but unfortunately the tendency of the joint to throw tho lubricant to the side, makes it neces
 lA CTIh f1a n