Arizona republican., 1918-07-28

By one of the anomlies that are almost habltual in the business world, it took twelve years for the Hotchkiss idea to achieve popularity in this country. l Perhaps this was due to the fact that it was an idea rather than a part or a device, which would be pushed by some manufacturing company The advantages of utilizing the spring in this way simply had to sink home to the American engineering fraternity in fate's own good time. No pressure was brought to bear to introduce the idea, which finally in 1913 won it's place as the predominating method of design for this part of the mechanism, purely and simply through its inherent merit At the present time nearly three -fifths of the cars on the American market embody Hotchkiss drive
 Driving Is Through Springs
 Stripped of complications Hotchkiss drive means simply that the propul- sive power is transmitted through the springs instead of through radius rods, etc. as used to be the custom, and also that the rear springs are called upon to take the torque or twist Of the whole rear axle assembly. The rear axle unit is peculiarly liable to twisting tendencies, because of its po- sition in the mechanism and functions. When the car is being driven straight ahead there is certain twisting movement on the part of the rear axle whenever the rate of speed is altered. This is somewhat different from the movement present when the brakes are applied. In this case the wheels are suddenly stopped whereas the [, n a f0va fp <l- direction in which it has been going, in accordance with the laws of inertia When the car is being started, the axle develops a tendency to turn for ward. In some cases where the springs are unusually flexible. the rear axles can actually be seen to turn forward when the car is being started.
 } How Strain Is Absorbed
 l Now, as we noted before, in cars em-
 bodying Hotchkiss drive, all this twist
 or torque of the rear axle assembly is
 taken care of by the springs. In other
 words the springs are called upon tc
 absorb this tendency to revolve. Fur
 there after the car is in motion. the rear axle and wheels must keep tho . rest of the vehicle moving by pushing
 1t. It is evident on moments
 thought that this is so, because tht
 driving wheels, the rear wheels givt the impetus to the whole vehicle IT i Hotchkiss drive this pushing function is also shouldered by the springs.
 Springs Specially Designed
 Obviously with the springs beins
 called upon to perform so many ant such diverse functions, they will neet to be especially designed for the work ,, The usual practice is to employ a mair leaf of particularly sturdy dimensions : and material, as nearly all of the worl , falls upon this keystone of the sprint . , arch. Again it is very important tha a satisfactory method of anchoring tn,
 spring to the axle be employed. Gu
 engineers have spent many thought , ful hours in the design of the seem ! ingly minor spring perches and sprin, clips. These parts demand the em ployment of the best grades of allo, steel carefully handled in the pro eesses of manufacture Castellate, nuts are generally used on the clips ; the nuts being firmly secured b,
 means of cotter pins. As genera thing two clips are found sufficient t distribute the torque or twist to tn spring as whole. relieving the centra ' leaf of some of the burden.
 Adjustments Must Be Watched k Right here let us emphasize the nee for the car owners inspecting tn e springs from time to time and seein e that the clips are kept snugly in plac, If the clips are allowed to becom
 loose. relaxing the pressure on tn spring. the driving force may yer 5 easily produce so much of strain tha e the part will be broken.
 c When the car owner understand just how important a part the spring play. he may be tempted to give ther
 more care than he usually seems {
 bestow upon them. Not only shout
 the shackle bolts be systematicall
 fabricated, but the spring leaves shoul
 be pried apart once or twice a seaso
 anyway, and be given thorough coat
 ing of graphite. The average sprin . suspension is adequate to the car . carries but it is not adequate | abuse. It must have a reasonabl amount of attention or it will fail, wit
 consequent inconvenience and expens
 to the car owner.