propeller shaft. The points that will wear soonest are the pins M, T, N, U, carried on the universal joint cross J. When looking over universal joints it is well to make sure that the sliding points are free and that the sleeve member does not bind on the propeller shaft. Where two universal joints are used it is not necessary to have a slip joint at both ends and one of the sleeve members may be fastened securely to the propeller shaft.

The universal joint at Fig. 364, B, is called a roller bearing joint and consists of a hollow, slit bronze sphere attached to one shaft and a steel sphere, which may also be hollowed, attached to or formed integral with the end of another shaft. Four adjustable studs carrying conical rollers at their inner ends are equally spaced around the outside sphere. The inside ball contains four slots into which the pins project. The slots are so shaped as to allow free universal action and get no back lash at any point.

Another form of joint designed to give a flexible drive is shown at C. This is increasing in popularity and is found on a number of cars for final drive though it is more widely applied as a driving connection between the clutch or gear box or for magneto or electric starting generator drive. Two three fingered spiders having a suitable boss attached thereto to receive the end of the driving shaft are bolted to discs of leather, the fingers of one spider member being placed between those of the other and the leather disc securely held to each of the spiders. Owing to the flexibility of the leather it is possible to drive parts that are not in absolute alignment, though this form of joint is not suitable for use where there is apt to be considerable movement between the parts and the other types of universal joint are better adapted owing to allowing a greater degree of motion between driven and driving shafts.

A simple universal that has been adapted to some extent for light work is shown at Fig. 364, D. This consists of a ball shaped center member having machined slots into which suitably formed yoke members fit. This joint, while popular for machine tools, is not widely used in automobiles and it is illustrated in order that the repairman may be familiar with all practical forms of joints. The form shown at Fig. 365, A, is that used on the National auto

mobiles and as two views are presented its construction should be easily understood. A driving member is keyed to the end of the transmission shaft and is securely held on the taper by a suitable clamping nut. The driving member is provided with two longitudinal slots in which square nuts or sliding blocks fit. These are mounted on a pin which is driven through the enlarged end of the propeller shaft. With this construction two joints are necessary,

one at the front end of the shaft, next to the gearbox, and another on the rear axle. After the joint has been in use for a time there may exist considerable looseness between the bearing pin and the hole in the sliding block and there may also be some depreciation of the slots in which the block slides. If the slots in the driving member are worn they should be machined out so that they are true and smooth though perhaps somewhat wider than they were originally. It is a very simple matter to make new case hardened blocks that will fit the enlarged slots in the driving member. The

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manner of covering the joints in order to retain lubricant and keep out the dirt is clearly shown in the illustration. A pressed steel cover member is designed to fit over the driving yoke while the propeller shaft end is encased with a flexible leather cover securely clamped to both driven shaft and flange on driving member cover. In order to make it easy to introduce new lubricant to the interior of the joints a screw plug is provided which is screwed into a fitting riveted to the leather covering. Where two of these joints. are used it is desirable to have the propeller shaft held so it may slide to some extent as the axle moves up and down yet not be loose enough to rattle. The desired end is easily obtained by interposing coil springs in each universal joint which bear against the enlarged end of the driven shaft and seat on the driving member retention nut.

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Other forms of joints which provide a certain amount of universal action are shown at B and C, Fig. 365. In the former there are but two rocking members whereas in the latter there are four rocking members. The driving member of the joint consists of a sleeve having a square hole made to receive the end of the driven member which is a square or rectangular in cross section but having rounded faces as indicated. In the form at B, two of the sides of this square ball" are in contact with thin discs having one side curved to fit the inside member and the other side flat to fit a side of the internal square. In the form shown at C, four of the rocker members are used instead of two. These rocker members do not interfere with the universal action and are valuable in that they provide for longer life than the ordinary form of wabble joint as there is ample contact surface between the driving member and the face of the rocker discs and there is also ample surface contact between the driven member and the rounded seats of the rocker discs.

Radius Rods, Torque Members and Control Linkage.-On every chassis there are a number of points where the motion is relatively slight but where the parts are subjected to considerable pressure. Among these may be mentioned the radius rods used with side chain drive cars and the torque members furnished when the bevel or worm drive axles are used. The form of the torque mem

TORQUE ON TORQUE ARM, THRUST ON SPRINGS.

TORQUE ON TORQUE ARM, Thrust on RADIUS ROD.

Fig. 366.-Conventional Method of Taking Driving Thrust and Braking and Driving Torque in Modern
Automobiles.

ber varies with the system of drive employed and is in turn, dependent upon the preferences of the designer. The reason it is necessary to provide a torque member with a shaft drive axle is that all the time the rear wheels are propelling the vehicle the reaction tends to turn the axle housing and this motion must be resisted by some arrangement that will hold the axle in its proper position. The torque members are also required when the brakes are applied to a car because there is also a tendency for the axle to rotate when the retarding force is applied to stop the wheels from turning. The various common forms of torque members are shown at Fig. 366, these illustrations having been reproduced from the Horseless Age.

The construction shown at A is a common one and is used on a number of cars, some of which, as the Overland, are sold in very large quantities. In this construction, the propeller shaft to which the bevel driving pinion is secured is carried by a long tube securely fastened to the axle at one end and carrying a yoke casting at the other supported by suitable bearings attached to the frame cross member. This yoke is mounted so it swivels on the axle tube, permitting the axle to be higher on one side than the other without stressing the joint, a condition that is often necessary and, in fact, unavoidable when running over rough roads. It is evident that the rear axle is also subjected to an up and down motion, this being due to roughness of the road surfaces. In order to provide for this movement the yoke casting is hinged to the frame cross members. When this construction is followed there are three points where depreciation can exist. The points that will wear soonest are the supporting pins or bolts at the ends of the yoke member that fit the frame. These may wear enough so that there will be appreciable lost motion, which means a rattling sound when the car is operated over any but the smoothest of roads. The remedy for this condition is a simple one, consisting only of replacing the worn pins and bushings in the yoke ends, if the construction permits or of reaming out the holes larger and fitting pins to correspond. The joint where the yoke swivels on the torque tube is usually of larger size and is provided with a generous grease cup. While it is not apt to wear as quickly as the joints of lesser area,