Tips and tricks
Automobile engineering
AUTOMOBILE ENGINEERING
For repair men, chauffeurs, and owners; covering the construction, care, and repair of pleasure cars, commercial cars, and motorcycles, with especial attention to ignition, starting, and lighting systems, garage equipment, welding, ford construction and repair, and other repair methods.
Prepared by a Staff of automobile experts, consulting engineers, and designers of the highest professional standing.
AMERICAN TECHNICAL SOCIETY, CHICAGO, 1921
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FOREWORD
The period of evolution of the automobile does not span many years, but the evolution has been none the less spectacular and complete. From a creature of sudden caprices and uncertain behavior, it has become today a well-behaved thoroughbred of known habits and perfect reliability. The driver no longer needs to carry war clothes in momentary expectation of a call to the front. He sits in his seat, starts his motor by pressing a button with his hand or foot, and probably for weeks on end will not need to do anything more serious than feed his animal gasoline or oil, screw up a few grease cups, and pump up a tire or two.
And yet, the traveling along this road of reliability and mechanical perfection has not been easy, and the grades have not been negotiated or the heights reached without many trials and failures. The application of the internal-combustion motor, the electric motor, the storage battery, and the steam engine to the development of the modern types of mechanically propelled road carriages has been a far-reaching engineering problem of great difficulty. Nevertheless, through the aid of the best scientific and mechanical minds in this and other countries, every detail has received the amount of attention necessary to make it as perfect as possible. Road troubles, except in connection with tires, have become almost negligible and even the inexperienced driver, who knows barely enough to keep to the road and shift gears properly, can venture on long touring trips without fear of getting stranded. The refinements in the ignition, starting, and lighting systems have added greatly to the pleasure in running the car. Altogether, the automobile as a whole has become standardized, and unless some unforeseen developments are brought about, future changes in either the gasoline or the electric automobile will be merely along the line of greater refinement of the mechanical and electrical devices used.
Notwithstanding the high degree of reliability already spoken of, the ears, as they get older, will need the attention of the repair man. This is particularly true of the cars two and three seasons old. A special effort, therefore, has been made to furnish information which will be of value to the men whose duty it is to revive the faltering action of the motor and to take care of the other internal troubles in the machine.
Special effort has been made to emphasize the treatment of the Electrical Equipment of Gasoline Cars, not only because it is in this direction that most of the improvements have lately taken place but also because this department of automobile construction is least familiar to the repair men and others interested in the details of the automobile. A multitude of diagrams have been supplied showing the constructive features and wiring circuits of the majority of the systems. In addition to this instructive section, particular attention is called to the articles on Welding, Shop Information, Electrical Repairs, and Ford Construction and Repair.
And yet, the traveling along this road of reliability and mechanical perfection has not been easy, and the grades have not been negotiated or the heights reached without many trials and failures. The application of the internal-combustion motor, the electric motor, the storage battery, and the steam engine to the development of the modern types of mechanically propelled road carriages has been a far-reaching engineering problem of great difficulty. Nevertheless, through the aid of the best scientific and mechanical minds in this and other countries, every detail has received the amount of attention necessary to make it as perfect as possible. Road troubles, except in connection with tires, have become almost negligible and even the inexperienced driver, who knows barely enough to keep to the road and shift gears properly, can venture on long touring trips without fear of getting stranded. The refinements in the ignition, starting, and lighting systems have added greatly to the pleasure in running the car. Altogether, the automobile as a whole has become standardized, and unless some unforeseen developments are brought about, future changes in either the gasoline or the electric automobile will be merely along the line of greater refinement of the mechanical and electrical devices used.
Notwithstanding the high degree of reliability already spoken of, the ears, as they get older, will need the attention of the repair man. This is particularly true of the cars two and three seasons old. A special effort, therefore, has been made to furnish information which will be of value to the men whose duty it is to revive the faltering action of the motor and to take care of the other internal troubles in the machine.
Special effort has been made to emphasize the treatment of the Electrical Equipment of Gasoline Cars, not only because it is in this direction that most of the improvements have lately taken place but also because this department of automobile construction is least familiar to the repair men and others interested in the details of the automobile. A multitude of diagrams have been supplied showing the constructive features and wiring circuits of the majority of the systems. In addition to this instructive section, particular attention is called to the articles on Welding, Shop Information, Electrical Repairs, and Ford Construction and Repair.
TABLE OF CONTENTS
- GASOLINE AUTOMOBILES
- EQUIPMENT FOR GASOLINE CARS
CLUTCH GROUP
TYPES OF CLUTCHES
Classification. Principal among the indispensable parts intervening between engine and road wheels, and one which may be a source of great joy or correspondingly great wrath, according to whether it be well or poorly designed and fitted, is the clutch. There are three forms into which clutches may be divided, all of which are in general use in the automobile. These different forms are:
(1) Cone clutches
(2) Disc clutches
(3) Plate clutches
The necessity for a clutch lies in the fact that the best results are obtained in an automobile engine when run at constant speed. In as much as the speed of the car cannot, from the nature of its use, be constant, it requires some form of speed variator. This is the usual gear box, or transmission, but, in addition, there is the necessity of disconnecting it from the motor upon starting, since the engine cannot start under a load. There is also the necessity for disconnecting the two when it is desired to change from one speed to another either by way of an increase or a decrease. So, also, when one wishes to stop the car, there must be some form of disconnection. There are, then, three real and weighty reasons for having a clutch.
Requirements Applying to All Clutches. In a serviceable clutch there are two general requirements which are applicable to all forms. These are gradual engagement and large contact surfaces, although the latter requirement may be made to lose much of its force by making the surfaces very efficient. In the cone clutch, gradual engaging qualities are secured by placing a series of flat springs under the leather or clutch lining. By means of these springs, acting against the main clutch spring, the clutch does not grab, since the large spring must have time in which to overcome the numerous small springs. In this way, the engagement is gradual and the progress of the car is easy as well as continuous.
The specific necessity in a cone clutch is a two-fold one - sufficient friction surface and proper angularity. The latter, in a way, affects the former, as will be discussed more in detail later. The angularity varies in practice from 8 to 18 degrees.
Cone Cutch. The cone clutch consists of two members, one fixed on the flywheel or other rotating part of the engine and the other fixed to the transmission shaft. The latter usually slides upon the shaft so as to allow engagement and disengagement, 4 spring holding the two together. When the smaller-diameter member is spoken of, it is usually called the male member, while the part of larger size is spoken as the female member.
An excellent example of the direct cone clutch is seen in Fig. 246, which shows the Studebaker clutch in section. The noticeable point about this clutch is its simplicity. It will be noted that the spring is entirely enclosed, so that when it needs adjusting the repair man must open the universal joint and operate the bolt A which regulates the tension of the spring.
Another good example of the simplicity of the cone clutch is seen in Fig. 247, which is an aluminum member with bosses cast for cork inserts. Between the inserts may be seen the flat heads of the copper rivets which hold the clutch facing in place. Obviously, this has the same disadvantage of internal, and thus inaccessible, spring.
In the cone type of clutch, shown in Fig. 248, the inaccessible spring is avoided. In addition, a number of small springs are used in place of one very large and very stiff one. The ease of adjustment and the greater ease in handling the springs make this clutch a much better design for average use from the repair man's point of view.
Disc Clutch. With its advent in 1904, the multiple-disc clutch has steadily grown in popularity, until today it is looked upon as the most satisfactory solution of the difficult clutch problem. Designers who have once adopted it, seldom, if ever, go back to another form, while of the new cars coming out from time to time nearly three-fourths are equipped with some form of disc clutch.
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(1) Cone clutches
(2) Disc clutches
(3) Plate clutches
The necessity for a clutch lies in the fact that the best results are obtained in an automobile engine when run at constant speed. In as much as the speed of the car cannot, from the nature of its use, be constant, it requires some form of speed variator. This is the usual gear box, or transmission, but, in addition, there is the necessity of disconnecting it from the motor upon starting, since the engine cannot start under a load. There is also the necessity for disconnecting the two when it is desired to change from one speed to another either by way of an increase or a decrease. So, also, when one wishes to stop the car, there must be some form of disconnection. There are, then, three real and weighty reasons for having a clutch.
Requirements Applying to All Clutches. In a serviceable clutch there are two general requirements which are applicable to all forms. These are gradual engagement and large contact surfaces, although the latter requirement may be made to lose much of its force by making the surfaces very efficient. In the cone clutch, gradual engaging qualities are secured by placing a series of flat springs under the leather or clutch lining. By means of these springs, acting against the main clutch spring, the clutch does not grab, since the large spring must have time in which to overcome the numerous small springs. In this way, the engagement is gradual and the progress of the car is easy as well as continuous.
The specific necessity in a cone clutch is a two-fold one - sufficient friction surface and proper angularity. The latter, in a way, affects the former, as will be discussed more in detail later. The angularity varies in practice from 8 to 18 degrees.
Cone Cutch. The cone clutch consists of two members, one fixed on the flywheel or other rotating part of the engine and the other fixed to the transmission shaft. The latter usually slides upon the shaft so as to allow engagement and disengagement, 4 spring holding the two together. When the smaller-diameter member is spoken of, it is usually called the male member, while the part of larger size is spoken as the female member.
An excellent example of the direct cone clutch is seen in Fig. 246, which shows the Studebaker clutch in section. The noticeable point about this clutch is its simplicity. It will be noted that the spring is entirely enclosed, so that when it needs adjusting the repair man must open the universal joint and operate the bolt A which regulates the tension of the spring.
Another good example of the simplicity of the cone clutch is seen in Fig. 247, which is an aluminum member with bosses cast for cork inserts. Between the inserts may be seen the flat heads of the copper rivets which hold the clutch facing in place. Obviously, this has the same disadvantage of internal, and thus inaccessible, spring.
In the cone type of clutch, shown in Fig. 248, the inaccessible spring is avoided. In addition, a number of small springs are used in place of one very large and very stiff one. The ease of adjustment and the greater ease in handling the springs make this clutch a much better design for average use from the repair man's point of view.
Disc Clutch. With its advent in 1904, the multiple-disc clutch has steadily grown in popularity, until today it is looked upon as the most satisfactory solution of the difficult clutch problem. Designers who have once adopted it, seldom, if ever, go back to another form, while of the new cars coming out from time to time nearly three-fourths are equipped with some form of disc clutch.
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