Tachometer
A device for continuously indicating speeds of rotation. Its principle is identical with that of the speedometer (see speedometer, centrifugal type, and speedometer, magnetic type). It reads, however in revolutions per minute instead of in miles per hour, and its drive shaft is usually directly connected to the shaft the speed of which is to be measured.
Tail Lamp
A small oil or electric lamp, carried upon the left hand side of the rear of an automobile, to warn following traffic of the presence of the vehicle and to illuminate the rear number plate. It displays a red light to the rear, a green light to the left, and a white light to the right, which is directed upon the number plate.
Tail Shaft
The rearward extension of a gas engine crankshaft, beyond the flywheel flange or other mounting, upon which the driven member of the clutch is supported, and upon which it rotates when the clutch is disengaged.
Talc
Finely pulverized soapstone (French chalk), which is of a slippery nature and is thus used to prevent rubber surfaces from sticking together. It is rubbed upon the surface of inner tubes and upon the insides of tire casings for this purpose and to reduce the friction between them.
Taper
A somewhat conical portion of a mechanical part, such as a shaft, usually upon an end of the same. E. g., one end of a shaft may be tapered and intended to receive a gear or similar part, the hub of which is bored out correspondingly conical and fitted upon the tapered end of the shaft. A nut is then screwed down upon the projecting, threaded end of the shaft against the surface of the hub, forcing the tapered surfaces into tight contact. A key (q. v.) may be employed to prevent rotation of the gear upon the shaft. See pin, taper.
Tappet
A rocker arm (q. v.).
Tappet Rod
A push rod (q. v.).
Taxicab
A public motor vehicle, with a closed or convertible body, operated for hire and fitted with a taximeter (q. v.), by which the charges for its use are automatically computed.
Taximeter
An instrument installed upon a public passenger automobile that is operated for hire, which automatically indicates the fare which the passenger is expected to pay, at any instant, while the vehicle is in his service. It is a combination of a trip odometer mechanism (see odometer, trip) and a clock, which, respectively, measure the distance traveled and the time consumed, these factors being combined in such a manner by the mechanism that a continuous indication is given in dollars and cents of what the service has cost the passenger at any instant after the vehicle is hired.
Telescope Joint
See slip joint.
Telltale
A sight feed (q. v.).
Terminal
One of the points of attachment through which an electric current is led into or out of a piece of electrical apparatus. It is generally a binding post (q. v.).
A specially formed piece of metal soldered or otherwise electrically connected to the end of a wire or cable and adapted to be conveniently and securely attached to a binding post or terminal of a piece of electrical apparatus. It may be in the form of a spring clip arranged to be snapped over or upon a binding post.
Terminal Pressure
The fluid pressure existing in an engine cylinder at the instant of the opening of the exhaust valve.
Testing Block
A stand or framework, suitably equipped with apparatus, upon which a motor, change speed gear or other power transmitting part of an automobile, or indeed, a complete chassis, may be quickly and conveniently mounted to enable a dynamometer test (q. v.) or other form of shop test (q. v.) to be.
Synonym: Testing stand.
Testing Body
A rude, skeleton body which is mounted upon a completed chassis while it is being given its road test (q. v.), wear and tear upon the highly finished body, which is to be delivered upon the chassis, thus being obviated. Special testing wheels are generally used upon the chassis, during the road test, instead of the highly finished wheels which belong with it.
Testing Track
A course, laid out upon privately owned land, upon which motor cars can be tested under road conditions without interference from other traffic or legal restrictions.
Thermal Efficiency
See efficiency, thermal.
Thermo-siphon
See water cooling, gravity system.
Thermostat
A device which is sensitive to temperature changes, and which when the temperature to which it is exposed changes materially from a predetermined value, is capable of setting into action mechanism which tends to readjust the temperature to its normal value. Its action is usually dependent upon the differential expansion and contraction, by temperature changes, of two substances (usually dissimilar metals.) Used in flash boilers to regulate the fire (see automatic fire regulator) and in electric vulcanizers (see vulcanizer, electric).
Third Gear
The highest gear ratio obtainable from a three speed change speed device (its high gear), and the next to the highest gear ratio obtainable from a four speed change speed device.
Synonym: Third speed.
Three Point Suspension
A method of supporting a motor crankcase, gearcase, unit power plant (q. v.) or the like upon a vehicle frame, by the employment of which the part so mounted is substantially insured against being stressed by the accidental warping of the frame. The part thus mounted is secured to the frame at three points, usually as follows: By an arm extending from each side of the front or the rear thereof to the adjacent frame side member, and by a third arm extending backward or forward from the middle of the rear or front end thereof to the middle portion of a frame cross member, this last mentioned support often being of trunnion (q. v.) construction. The principle involved in this method of suspension is that three points, no matter how located, are always in the same plane, and that no matter how the vehicle frame distorts in service, and although the plane of the mounted part may be altered as a whole, there is practically no tendency to change the position of one supporting arm relatively to another and thus no tendency to stress the material of the part. Since four points may be so located as not to lie in the same plane, a part secured to a frame by four or more arms must necessarily be subjected to a warping tendency whenever the frame so distorts as to tend to move the parts of it which act as supports out of the same plane.
Throttle Valve
In connection with a gas engine, the valve which controls the passage of the gaseous charge from the carburetor to the cylinders, in response to the suction existing therein, by contracting or enlarging, at the will of the operator, the effective area of the gas passage. Its degree of opening determines the weight of fuel vapor drawn into each cylinder, and thus the explosion pressure therein and the amount of work done by the motor, per cycle. It is generally a part of the carburetor (see diagram carburetor, automatic) and generally located close to its point of attachment to the intake pipe (q. v.),and is most commonly a butterfly valve (q. v.), but may be a piston valve (see valve piston), a sliding valve or the like.
In connection with a steam engine, the valve in the steam pipe which controls the flow of steam from the boiler to the engine. It may be a slide valve with self-adjusting seat, a form of globe valve moved by a multiple threaded screw or the like.
Throttle (v.)
To restrict the rate at which steam or gas is received by a steam or gas engine and thus to reduce its output. To throttle down.
Throttle, Auxiliary
A valve in the steam pipe of a steam car, additional to the regular throttle valve, arranged so as completely to close the same and thus to prevent the starting of the car upon the unintentional or malicious opening of the regular throttle and to prevent its accidental starting in case the regular throttle leaks. It may be provided with a removable handle or a locking device, as a precautionary measure.
Synonym: Safety throttle.
Throttle, Clutch Operated
In connection with a gas vehicle motor, a mechanism which automatically nearly closes the throttle valve, when the operator disengages the clutch and the load is consequently removed from the motor, the throttle valve being permitted to return to its set degree of opening upon the reengagement of the clutch. It acts to reduce the speed of the motor to a safe idling rate and thus to prevent racing when the clutch is thrown out.
Throttle, Foot
See accelerator.
Throttle, Governor Controlled
A throttle valve which, in some commercial vehicle gas motors, is entirely distinct from the hand or foot controlled throttle valve, and which is automatically opened and closed by a governor (q. v.), its function being to limit the speed of the motor to a predetermined maximum value.
Throttle Lever
The hand operated lever, by means of which the throttle valve is opened and closed. On gasoline and many steam cars, it is located upon the steering column and moves over a stationary sector (the throttle quadrant or segment) so designed as to retain it in whatever position thereon it is set by the operator.
Synonym: Hand throttle,
Throttle Linkage
The mechanism which transmits the opening and closing movement of a throttle control device (lever, pedal or otherwise) to the throttle valve itself.
Throttle Shaft
The shaft, within or attached to the steering column, which transmits the movement of the throttle lever to the rest of the throttle linkage.
Throttle Spindle
The spindle or shaft, in a carburetor, upon which the throttle valve rotates.
Throttle Wheel
The wheel, located upon the steering column, under the steering wheel on some steam cars, which acts as the throttle valve control device.
Through Bolt
In a gas motor, one of a number of long bolts passed through the cylinder flanges (q. v.), the upper wall of the crank case, and the main bearing hangers and caps, so as to themselves assume the stresses acting between the cylinders and the bearings, and thus relieve the material of the crank case from these stresses.
Thrust Bearing
See bearing, ball thrust. Not necessarily a ball bearing, however, roller bearings being sometimes used and plain stepped bearings with washers between the shoulder of the shaft and the end of the bearing being sometimes employed.
Tickler
The device employed to prime (q. v.) a carburetor. See carburetor float depressor.
Tie Rod
The rod forming a part of the steering gear, located transversely of and at the front of a motor car, the ends of which each bears a clevis (q. v.) by which they are pivotally connected respectively to the ends of the right and the left hand steering knuckle arms (q, v.). Its function is to interconnect the two front road wheels so that they are at all times maintained in the straight ahead or in correspondingly deflected positions. Its length is usually slightly variable so that the front wheels can be adjusted to parallelism.
Time (v.)
To adjust the period of occurrence of the ignition spark with relation to the cycle of an internal combustion motor. (See ignition, point of; advance; retard). (See also valve timing).
Tinier
In an ignition system, the device which automatically closes and opens the primary circuits at such periods as to produce sparks at the instants when they are required by the gas motor with which it is used. It usually consists of a grounded (q. v.) contact-carrying arm, rotated by one of the motor shafts (at one-half the speed of the crankshaft for a four stroke cycle (q. v.) motor and at crankshaft speed for a two stroke cycle (q. v.) motor, and a number of equally spaced, metallic contact segments (one for each engine cylinder) fastened upon the internal surface of a stationary, cylindrical, insulating shell which is carried (usually on a ball bearing) upon and concentric with the contact arm shaft in such a manner that the contact arm, when rotated, successively makes and breaks connection with the segments. The timer shell with its contact segments is capable of being rotated through an arc, by means of the spark lever (q. v.) and linkage so that the period in the engine’s cycle at which the contacts are made and broken may be varied and the desired angle of advance (q. v.) can be secured. A primary wire from one of the spark coils (q. v.) is connected to each segment, and, as the contact arm rotates, it touches each contact segment in succession and energizes each ignition circuit successively, the connection being such that sparks are produced in the cylinders in the proper firing order (q. v.). A timer of this type is used with multiple vibrator coils (see ignition, multiple coil), and in the master vibrator system (see ignition, master vibrator). A timer is employed in connection with a distributor (q. v.), usually being built integrally therewith in battery systems, all the contact segments of such a timer being electrically connected together, so that the primary circuit of the single spark coil (see ignition, single coil) is closed at the instant each cylinder requires a spark. In timers used in single spark systems (see ignition, single spark), the contact arm of the timer is usually replaced by a cam (see cam, ignition) with as many projecting faces as there are cylinders to be ignited. The cam projections, as they pass them, successively close a pair of spring opened, platinum tipped contact points which are in circuit with the primary of the single coil used in the system. A magneto make and break (q. v.) is essentially a timer.
Synonym: Commutator,
Timer, Automatically Advanced
A timer so devised as automatically to advance (q. v.) the spark with increasing motor speed, and to retard it with decreasing motor speed, so that ignition always takes place at the most advantageous point (see ignition, point of) in the cycle of each cylinder and manual adjustment of the spark is obviated. A centrifugal device, similar to that used in an engine governor (see governor, centrifugal), rotated by the timer shaft, is mechanically so connected with the timer as to alter the angular relation of the timer arm or cam to the timer shaft, or to alter the angular position of the timer shell and contact segments as to secure the spark position demanded by each change in engine speed. Automatic timing is applied to magnetos, usually automatically varying the angular relation to the magneto driving shaft of the cam which operates the make and break device.
Timer, Ball Contact
A timer the contact arm of which carries a spring pressed steel ball, which makes successive electrical connection with the contact segments, which are usually of hardened steel, a rolling action between the contact parts thus being secured.
Timer, Brush Contact
A timer the rotating arm of which bears a spring pressed brush (q. v.), which makes a sliding contact with the segments or one in which each segment is replaced by a pair of spring contacts between and in rubbing contact with which the timer arm passes, or any timer in which a sliding rather than a rolling electrical contact is employed.
Timer, Roller Contact
A timer, the rotating arm of which terminates in a spring pressed, hardened steel roller, which successively runs over the hardened steel contact segments with a minimum of wearing action.
Timer Shaft
The shaft which operates a timer. Such a shaft runs at one-half engine speed in the case of a four stroke cycle (q. v.) motor, and thus may be identical with a cam shaft (q. v.). In the case of a two stroke cycle (q. v.) motor it runs at crankshaft speed and may be identical therewith. Very often the timer is driven by a special shaft arranged vertically or slightly inclined on one side of the motor and driven by spiral or bevel gears from a camshaft or otherwise.
Synonym: Commutator shaft.
Timing Gears
See half-time gears.
Timing Marks
See flywheel markings.
Timing Range
The total angle through which the occurrence of the spark can be varied by moving the spark timing mechanism from its most advanced to its most retarded position. It may be measured as the total angular movement produced in the adjustable member of the timer or as the total angular movement of the motor flywheel between its position when the spark occurs under full advance and that at which it occurs when fully retarded; the angle as measured upon the flywheel being twice that measured at the timer, in the case of a four cycle motor.
Tire
A coninuous circular band, fastened around the periphery of a road wheel outside the felloe, the external surface of which forms the actual surface of contact between the wheel and the roadbed. Its function is to resist the wearing effect of the road surface, and, in automobile practice, to protect the structure of the wheel, the car mechanism and the passengers or load against road shocks and to reduce the noise of the vehicle’s operation, to attain which results the material of the tire is usually of a somewhat yielding and resilient nature, such as rubberof which is so constructed as to grip the road surface more securely than does a smooth tread. The treads of pneumatic tires of this class may be provided with a multiplicity of molded knobs of rubber arranged in various patterns; the tread may consist of a leather band, studded externally with a multiplicity of steel rivets, or it may be othewise roughened so as to tend to indent the road surface and thus to offer extra resistance to the tractive effort and to side slip.
Tire, Block
A form of solid rubber tire, mainly used upon commercial vehicles, built up of closely spaced blocks of rubber, usually of somewhat rectangular section and thus possessing a tread which is not continuous, but scalloped. The specially constructed bases of the rubber blocks may be held in rectangular sockets in a retaining band (either continuous or sectional) which is bolted to the wheel felloe, or they may be secured in a channel rim by means of side wires. Two parallel series of such blocks are frequently used upon the same wheel, the blocks of the two series being “staggered». Such tires possess excellent tractive and anti-skid properties, on account of the tendency of the separate blocks to cling to or to indent the roadway. Individual blocks of such tires which have become damaged can be separately replaced.
Tire, Clincher
A tire of the pneumatic or solid rubber type, adapted to held in a clincher rim (see rim, clincher) mainly by the tendency of its base forcibly to expand transversely under inflation or by its own elasticity. Such a tire is made with a continuous bead (see tire bead) upon each side of its base, which is forced under the respective incurved edge of the rim. In pneumatic tires of this type a number of retaining bolts (staybolts) are employed, which pass through the felloe and rim and the appropriately shaped beads of which (on the outside of the rim) bear against the inside edges of the base of the tire casing, when the bolts are tightened, drawing it against the rim and forcing the edges of the beads into the clinchers, thus resisting any tendency to creep (q. v.) and to leave the rim.
Tire, Cushion
A tire depending for its resiliency upon the elasticity of rubber, and differing from a solid rubber tire (see tire, solid rubber) in that the rubber is so distributed as to impart to the tire peculiar yielding qualities.
Such a tire may be constructed with a continuous hollow centre or core, or with a hollow centre divided into cells by rubber bridges; holes or cells may be provided in its tread or sides; the sides may be hollowed or notched; the tread may be provided with several continuous ridges which yield under pressure, or any expedient may be adopted to secure a greater freedom of bending of the tire under load than is obtainable in a rubber tire of solid Q-shaped section. In resiliency, the cushion tire is intermediate between an ordinary solid tire and a pneumatic, and is used upon some commercial vehicles and upon some pleasure vehicles, chiefly electrics and high wheel cars.
Tire, Dual
The combination of two like tires, either of the solid or pneumatic type, side by side, in suitable rims, upon the same wheel. Dual solid tires are more successful than a single tire of equal width upon heavily loaded wheels, for the reason that there is secured a more uniform distribution of driving and braking stresses over the tire base. Dual pneumatic tires are used upon the wheels of heavy vehicles which cannot be economically operated upon single tires of the largest sizes commercially obtainable.
Synonym: Twin tires.
Three tires are sometimes applied in a similar manner to exceedingly heavily loaded wheels of commercial vehicles. (Triple tires.)
Tire, Flat Tread
A pneumatic tire the cross-section of the central portion of the tread of which is a straight line instead of the arc of a circle and which thus presents to the road a flat surface of considerable width, even though no flattening of the tire takes place. Such treads are sometimes employed with the idea of obtaining superior road adhesion, greater security from puncture, greater immunity from skidding and superior wearing qualities.
Tire, Mechanically Fastened
A pneumatic tire the inflation of which plays no part in holding it to its rim, as it does in the case with clincher and most quick detachable tires.
Positive mechanical holding devices are provided which secure it in place whether it is in an inflated or deflated condition.
Synonym: Bolted-on tire.
Tire, Pneumatic
A tire which owes its resiliency to air, confined under pressure, between the rim of the wheel and the tire tread. In its usual form it consists of a continuous circular, tubular casing (see tire casing), fastened by the edges of its base, upon the wheel rim, within which is fitted an endless circular, air-tight tube, the inner tube (q. v.), which, when inflated with air to a considerable pressure distends, presses against the rim and the inside walls of the casing, thus giving the tire a rotund shape under load, and confining a highly elastic body of air between the roadway and the rim of the wheel. The casing and inner tube are capable of bending, without large waste of energy, to conform to irregularities of the road surface, partly or wholly “absorbing” them and thus preventing jolts which would otherwise be communicated to the wheel and the vehicle.
Tire, Puncture Proof
A pneumatic tire in or on the casing of which is provided an armor of steel or other impervious plates which deflect puncturing objects before they reach the inner tube, or any pneumatic tire in which the inner tube is protected against external damage.
Tire, Quick Detachable
A pneumatic tire adapted to be mounted upon a quick detachable rim (see rim, quick detachable) so that it can readily be put on and taken off.
Tire, Single Tube
A pneumatic tire, in which the casing and inner tube are intergral, the latter being .merely the air-tight inner layer of nearly pure, lightly vulcanized rubber, the whole forming an endless closed tube of circular section. Equally spaced metal lugs, vulcanized into the inner face of the tire, receive screws driven through the felloe and rim and hold the tire in place, cement also sometimes being used. Occasionally employed upon electric vehicles, a special light-walled and highly resilient form being usually chosen.
Synonym: Hosepipe tire.
Tire, Solid Rubber
A tire the resiliency of which is due to the yielding quality of compounded rubber in the form of a band of somewhat Q shaped section, applied to the periphery of a wheel in a rim of somewhat channel shape. Such tires are generally used upon commercial vehicles and occasionally upon high wheel pleasure cars and others, as they deaden the noise of the wheel contact with the roadway, absorb vibration to quite an extent and possess good road adhesion.
Tire, Solid Rubber, Internally Wired
A solid rubber tire, which is held in its rim by the constrictive action of one or more continuous wires which are embedded in the base portion of the tire throughout its entire length. The wires are stretched, by a special machine, after the tire is on the rim and the two ends of each are united by welding or otherwise so that each wire forms a complete band, under heavy tension.
Tire, Solid Rubber, Metal and Hard Rubber Base
A solid rubber tire with a base made up of a steel band externally provided with circumferential dovetail projections, upon which is molded a layer of hard rubber, the external surface of which is vulcanized to the rubber body of the tire. Such tires are especially intended for use upon demountable rims, the inside surface of the steel band being held upon the rim by wedge like rings, one of which is usually clamped to the wheel by bolts.
Tire, Solid Rubber, Mesh Base
A solid rubber tire, in the base of which is embedded a meshwork of wires which prevents it from stretching and forms an unyielding base. It is secured in a channel shaped rim, one flange of which is removable, and which when bolted on, compresses the base transversely and holds the tire from creeping.
Tire, Solid Rubber, Side Wired
A solid rubber or similar tire which is secured in a somewhat channel-shaped rim by two steel wire bands drawn tightly around between each edge of the rim and the neighboring edge of the tire base. The base of the tire is given rigidity by numerous cross wires vulcanized into it upon the ends of which the two side wires bear.
Tire, Wood Block
A tire, built up of blocks of hard wood secured in and filling a channel rim with the grain of the wood perpendicular thereto, the faces of the blocks being turned down to a true circle. Such a tire is much less noisy, somewhat more resilient and less likely to slip than a steel tire, and is occasionally used upon heavy commercial vehicles.
Tire Base
That portion of a tire which is immediately in contact with the rim and by which it is held in position thereon. The term is especially applied to solid rubber and cushion tires, the bases of which are usually of special rigid construction, in order that they may be securely held, while the tire proper is of a yielding nature.
Tire Bead
The two edge portions of the base of a tire which are grasped by the sides of the rim (see tire, clincher). The bead of pneumatic tire casings is formed of a strip of hard rubber around which the rubberized fabric of the tire carcass (q. v.) is built up to give the required shape. In clincher pneumatic tires the bead is hook-like, and adapted to fit under the incurved edges of the rim. In some pneumatic tires for use on quick detachable rims the bead is not hook-like but straight-sided (straight or Dunlop bead) and in the bead is enclosed a continuous elastic wire cable (cable base tire) which prevents the base from stretching and, by contracting under inflation, holds the casing tightly upon the rim.
Tire Breaker Strip
In a pneumatic tire casing a strip of heavy fabric applied between the cushion (q. v.) and the rubber of the tread.
Tire Carcass
The structural or stress resisting portion of a pneumatic tire casing to which the tread and other parts are applied. It is built up of rubberized cotton fabric, wound diagonally around a core of the required shape and size and compacted into a solid mass by pressure and vulcanization.
Tire Carrier
A support attached to a car in which extra tires or demountable rims are carried. The tires are frequently strapped at three points to forked irons, two of which extend out from the car body and one from the running board, or they may be held in suitable supports attached to the rear of the body.
Synonym: Tire holder. Tire irons.
Tire Case
A waterproof and dustproof envelope of the shape and size of a pneumatic tire, designed to be fitted around a spare tire to protect it from deterioration while it is carried on a car. It is usually made of enamel cloth and is held. tightly about the tire by a contracting wire spring sewed ino the fabric.
Synonym: Tire cover.
Tire Casing
A pneumatic tire exclusive of its inner tube. The wear and stress resisting external portion or envelope, which is secured to the wheel rim. Synonym: Tire shoe. For parts thereof see tire bead, tire carcass, tire tread, tire cushion, tire flap, tire breaker strip.
Tire Chain
A traction increasing and anti-skid device (q. v.), consisting of two steel chains which fit entirely around a tire on each side thereof near its base. These two side chains are united by a series of short, uniformly spaced cross chains of hardened steel, the ends of which are hooked into links of the side chains so that they lie across the tread of the tire. The two ends of each side chain are held together by a snap hook which is released when the tire chain is put on or taken off. In use, the cross chains indent a yielding roadway, and increase the adhesion of the wheel thereto and, on hard road surfaces, wedge between it and the tire and reduce the slipping tendency.
Tire Cushion
A layer of nearly pure rubber applied, in the manufacture of a pneumatic tire casing, between the tire carcass (q. v.) and the breaker strip (q. v.) or strips, to act as a buffer between the tread and the body of the tire.
Tire Filling
A composition sometimes used to completely fill the air space within a pneumatic tire, thus rendering it immune to puncture without entirely destroying its resilient qualities. Such compositions consist of mixtures of somewhat resilient, spongy or jelly-like materials, such as glucose, glue, glycerine, etc., which are introduced into the air tube, when in a melted condition, by means of air pressure, and assume, upon cooling, a resilient solid condition.
Tire Flap
A fabric lip or band, so attached, by one edge, as to lie around the inner circumference of a quick detachable pneumatic tire casing, and which, after the inner tube is placed in position, is so adjusted that it intervenes between it and the rim, thus protecting it from pinching and rusting. Synonym: Tire chafing strip. Tire Gauge See gauge, tire.
Tire Inflater
See air bottle.
Tire Inner Shoe
A circular band of leather, strong fabric or other material of such shape as to fit between the inside of a pneumatic tire casing and the inner tube and thus to reinforce the former against the outward pressure of the latter, thus assisting in preventing blowouts and in resisting punctures. Principally used with casings which have become weakened in use. See blowout patch.
Synonym: Inside tire protector.
Tire Inner Tube
See inner tube.
Tire Patch
A prepared piece of rubber of such quality, size and shape as to be conveniently cemented or vulcanized over a puncture in an inner tube to close the same. The edges of the patch are usually beveled off and one side of it is often prepared with a rubber cement.
Tire Protector
A band of highly resistcnt and impenetrable material applied to the tread of a pneumatic tire to relieve the tread from road abrasion, to resist the attacks of puncture producing objects and to strengthen the casing against blowouts. It may be a band of leather cemented or otherwise permanently affixed to the tread and studded with steel rivets or a detachable endless band consisting of layers of leather externally bearing steel rivets or containing overlapping steel plates, which is held upon the tire by the outward pressure of its inflation and by a series of contractile springs acting to hold its edges in tension and closely against the tire. Such protectors are generally designed to act as anti-skid devices (q. v.).
Tire Pump
An air pump or compressor used to inflate pneumatic tires by forcing air into their inner tubes. See illustration under air pump.
Tire Pump, Power
A tire pump operated by mechanical 1 lower. Portable pumps for use upon automobiles may consist of a combination of one or more pump cylinders, the pistons of which are driven from a crankshaft which is, in turn, rotated by being thrown into gear with a shaft of the vehicle motor, or by means of a friction pulley forced into contact with the motor flywheel or by suitable mechanical connection to a jacked-up road wheel. Another type (impulse pump) is operated by motor cylinder pressure and consists of a double diameter piston (see piston, double diameter) and cylinder arrangement which is screwed into a spark plug hole of the motor. The alternating compression pressure and suction, within the motor cylinder, acting upon the larger of the pump pistons reciprocates it and causes the smaller piston and its cylinder to reciprocate as well and it and its cylinder to act as an air pump. A stationary power tire pump, such as used in garages, usually consists of a multicylinder air pump, operated by an electric motor or from shafting, which maintains a predetermined air pressure in a tank from which air can be drawn for tire inflation.
Tire Shoe
A tire casing (q. v.).
Tire Sleeve
See blowout patch.
Tire Staybolt
See tire, clincher.
Synonym: Tire lug.
Tire Tape
See friction tape.
Tire Tool
A hand tool employed to facilitate the removal from and replacement upon their rims of pneumatic tire casings.
Such tools are stiff steel levers, of a variety of shapes, adapted to act, to the utmost advantage, between the beads of the tire and the rim.
Tire Tread
The part of a tire which is in actual contact with the road surface and thus has to resist the abrasion and cutting action thereof. In pneumatic tire casings, it is the outside layer of specially compounded rubber adapted to resist wear and cutting by sharp objects and, at the same time, to prevent water from entering the fabric portion of the tire. It is of considerable thickness along the line of contact of the tire with the road and. thinner along the sides of the casing, and a portion of it is often deeply embossed into various shapes for anti-skid (q. v.) purposes.
Tire Valve
An inwardly opening, spring closed valve, through which air is forced into the inner tube of a pneumatic tire and by which it is confined therein. The valve is placed in position by screwing it into its seat in the valve stem (q. v.).
Tire Valve Stem
The externally threaded metal tube, one end of which enters, airtight, through the wall of an inner tube and through which air passes into and out thereof. It contains the seat for the tire valve (q. v.), and its free end is provided with an internal thread to receive a pump connection and an external thread upon which an airtight cap is normally screwed. The stem is of such length that, when the inner tube is in place, its free end protrudes accessibly through a hole in the rim and felloe, a ring nut being screwed down upon the stem so as to bear against the felloe and draw the inner tube tightly against the inside of the rim, and a dust cap (q. v.) is usually screwed down upon this nut.
Tonneau
An unenclosed body used especially in touring, with a front seat for two passengers about midway of the chassis and a seat for three nearly over the rear axle, somewhat overhanging the general side lines of the vehicle. Entrance to the rear seats is by a door on each side, which when shut entirely encloses the tonneau space. Chair seats for two passengers are sometimes added between the two main seats. Synonym: Touring body.
Tonneau, Baby
A small tonneau accommodating two instead of three passengers upon the rear seat, and with no space for extra seats between the front and rear seats.
Synonym: Toy tonneau, miniature tonneau, pony tonneau, demitonneau.
Tonneau, Detachable
A tonneau body of which that portion to the rear of the front seat-backs and comprising the rear seating accommodations (the tonneau proper) is removable, as a unit, from the vehicle frame upon the loosening of bolts. When so removed the rear portion of the car becomes a flat deck or trunk platform, upon which a truck box or similar attachment may be mounted, thus permitting the same car to be used as a two passenger car, a four passenger car or for light commercial purposes.
Tool Box
A box in which automobile tools are carried, usually constructed of pressed steel and generally mounted upon one of the running boards of a car.
Tool Steel
See steel, tool.
Top, Cape
A folding top of waterproof fabric attached to inverted H shaped bows which, when extended, forms a rain and sun proof protective covering over a car, extending from the extreme rear to a point slightly forward of the dash, the fabric beingbrought down for a short distance along its edges, but “leaving the sides and ends of the car practically open. The lower ends of the bows are supported upon two top irons on each side of the body, on pair being located close to the rear and the other pair nearly in line with the front seat. Two bows are generally used at the front and either .two or three at the rear. The top is kept tightly extended by means of two pairs of adjustable top straps attached respectively to the two sides of the front and of the rear thereof, the other ends of the front straps being hooked into eyes fastened to the front of the car frame and the other ends of the rear straps to the rear portion of the body. In putting down the top, the front straps are unhooked, and the front bows are detached from the front irons and attached to the rear irons and the top collapsed rearwardly, the bows being closely strapped together with the top fabric folded among them. Detachable, waterproof curtains, with celluloid windows, which button onto the top and onto the body at the sides and rear of the car (side curtains), may be attached to completely close in the passengers, in inclement weather, and a curtain with celluloid windows, ordinarily carried rolled up on the front bow, may be let down and buttoned to the dash, to close in the front of the car (storm front).
Synonym: Cape cart top.
Top Cover
A waterproof fabric cover, so shaped as to slip over a top when it is folded and to button securely about it, thus hiding it from view and protecting it against soiling.
Synonym: Slip cover, envelope.
Top Circle
With reference to a gear wheel, the imaginary circle drawn through the points of its teeth.
Torpedo Body
See body, gunboat.
Torque
The turning or twisting effort exerted by or upon a rotating part, such as a shaft, and measured by the moment of the forces acting. It is the product of the turning force and the perpendicular distance of its point of application from the axis of rotation. If the force is expressed in pounds and the distance in feet or in inches, the torque is expressed in pounds-feet or pounds-inches, respectively.
Synonym: Turning moment.
Torque Rod
A rod, generally tubular or of I-section, employed to resist the tendency of an automobile driving axle housing to rotate under the reaction of the driving and braking forces. It is located lengthwise of the vehicle, its rear end being secured rigidly into some part of the axle structure, usually the driving gear housing, and its front end secured to a frame cross member, this end usually been confined between two spiral springs, held in a suitable fitting with the intention of permitting slight deflections of the rod to cushion starting and braking shocks. Sometimes two tubes are used, their rear ends being bolted, respectively, to the upper and lower edges of the drive gear housing, and their front ends united at the spring support on the frame, a triangular structure thus being formed. A torque rod is used upon most shaft driven cars having drive shafts of the double jointed type (see drive shaft, double jointed), although in some small cars, the rear springs, which are tightly clipped to the axle housing, act to resist its rotation. In cars with drive shafts of the single jointed type, the drive shaft housing (q. v.) is often arranged to act as a torque rod, its front end being secured to a frame supported part so that it can pivot thereon at a point concentric with the universal joint and its rear end being rigidly secured to the drive gear housing. Under such conditions the housing also acts as a distance rod (q. v.).
Touring Car
A motor car, usually of the five or seven passenger tonneau type, especially intended for use in making long, continuous runs over all kinds of roads at speed, and with comfort to its passengers, in contradistinction to a runabout intended for use in making short, local trips. It is usually rather highly powered, with large ‘capacity for supplies and luggage, a long wheelbase, specially easy riding springs and luxurious seats, and specially fitted with conveniences tending to make its occupancy comfortable during long periods.
Town Car
A motor car with a closed or convertible body, usually hung rather low to afford easy access and egress, primarily intended for city use, such as shopping and calling. Such a car is usually not especially high powered, but is designed with a small turning radius (q. v.) and a capacity for rapid acceleration to facilitate its being maneuvered handily in crowded traffic. Limousine, landaulet, coupe and other similar bodies are employed.
Track
The gauge of a vehicle (q. v.).
Traction
The adhesion of the wheels of a vehicle to the roadway; that is, the frictional force acting between them and the road, which furnishes the reaction against which the tractive effort acts in moving the vehicle and against which the braking effort acts in stopping it. It is the product of the coefficient of friction of the tires on the roadway and the weight supported upon the driving wheels. When the tractive effort or braking effort exceeds the traction, the driving wheels slip and the vehicle fails to move or fails to stop promptly. Imperfect or diminished traction results from icy, muddy or otherwise slippery roads, unsuitable tires or too lightly loaded driving wheels.
Traction Increasing Device
See mud hook, tire chain and tire, anti-skid.
Tractive Effort
The force applied, tangentially, at the point of contact of a driving wheel with the roadway which tends to move a self-propelled vehicle. Knowing the horse power P being applied to a pair of driving wheels, the tractive effort in pounds is
F = 5025.2 P/RN
where R is the wheel radius in feet and N is the speed thereof in revolutions per minute.
Tractive Resistance
The resistances acting at the points of contact of the wheels of a vehicle with the surface of a level roadway, which opposes the rolling of the wheels over it and thus the movement of the vehicle. Such resistance varies with the load carried, the kind and width of tires used and their condition, the character and condition of the road surface, the wheel diameter and vehicle speed and other factors. It is usually expressed in pounds per ton of weight moved.
Synonym: Road resistance.
Tractor
A motor car designed to draw trailers (commercial vehicles without motive power) or to drag agricultural or other similar machinery.
Synonym: Traction engine.
Also a motor-car mechanism adapted to be attached to the forward end of a horse drawn vehicle and thus to convert the latter into a self-propelled vehicle.
Synonym: Forecarriage.
One type of tractor consists of a power chassis with a single front wheel for steering purposes, the rear of this chassis being made fast to the fifth wheel of the horse-drawn vehicle, the front wheels of the latter receiving the power from the tractor and supporting its rear portion, the whole constituting a five wheel vehicle. Deflection of the front wheel deflects the tractor portion and turns the fifth wheel and the two driving wheels, thus permitting the whole vehicle to be steered and manoeuvred in a small space.
Transfer Passage
In a two (stroke) cycle motor, the passage through which the fuel charge, which has been compressed in a separate chamber, is allowed to expand and flow into the working cylinder. Its point of entrance into the crank case or other chamber in which the charge is compressed is called the transfer port and its point of entrance into the working cylinder is called the inlet port. The transfer passage is usually cast in the cylinder wall from the crank case to the working cylinder space, but, in multiple cylinder engines, it may be a passage extending from the pumping space of one engine to the working cylinder of the adjacent engine. See diagram under two cycle engine, three port type.
Transformer
See coil, induction.
Transmission
A change speed gear (q. v.).
Transmission Axle
A driving axle to the front side of the gear housing of which is bolted the rear end of the case (gear case) containing the change speed gear (q. v.) of a gasoline automobile, the front end of the drive shaft (q. v.) (either single or double jointed) being connected directly to the clutch shaft, and its rear end to the primary shaft of the change speed gear, upon the final drive shaft of which is directly mounted the driving pinion of the bevel gear drive (q. v.). In this construction there are but two units to be mounted upon the frame: the engineclutch unit at front and the change speed gear-axle unit at the rear.
Transmission Brake
See brake, transmission.
Transmission Efficiency
See efficiency, transmission.
Transmission Line
A term applied to all the elements concerned in the transmission of power from the motor to the driving wheels of an automobile, including the clutch and its shafts, the change speed gears and their shafts, the universal joints, differential gear, axle shafts and drive shaft or chains and sprockets of the final drive.
Tread
The gauge (q. v.) of a vehicle. Tread
See tire tread and tire, anti-skid. Trembler See magnetic vibrator.
Truck Box
A box adapted to be mounted upon the rear of an automobile for commercial purposes. The term is usually applied to a box which can be attached and detached at will, in place of a tonneau or rear deck, to enable a car to be used for several classes of service.
Trunk Rack
A folding rack, usually of steel construction, attached to the rear of an automobile body and adapted to hold a trunk or other luggage and to be folded into small compass when not in use.
Trunnion
A projection attached to a movable structure, which fits into a suitable socket in a stationary part and forms a pivot upon which the supported structure may rotate slightly (usually in a vertical plane). The end support of a motor or other mechanism which is on a three point suspension (q. v.) is often a trunnion, and a trunnion is sometimes used upon each side of a radiator to give it a slight freedom of motion in the radiator brackets.
Truss
A construction designed to give transverse stiffness to a structural member. See axle, trussed, and frame, trussed.
Try Cock
A gauge cock (q. v.) or a cock set horizontally into a housing containing oil, the opening of which indicates by the outflow of oil therethrough, or its failure so to outflow, whether the oil level is or is not above the point of insertion of the cock.
Tungsten Lamp
A form of electric incandescent lamp the filament of which is of tungsten wire and which is highly efficient as compared with the carbon filament lamp, consuming from 1.0 to 1.25 watts, per mean horizontal candle power. It is generally used in all automobile electric lighting systems.
Tune Up (v.)
To make such adjustments upon a motor car mechanism as to cause all parts to work together with the utmost harmony and efficiency.
Tungsten Steel
See steel, tungsten.
Turnbuckle
A device for adjusting the length of a structural or control rod. In one common form, the rod is divided at some convenient point in its length and the adjacent ends are threaded respectively right and left handedly. A long nut, with its two ends threaded correspondingly right and left handedly, is screwed onto the two threaded ends of the rod. Turning the nut in one direction draws both ends of the rod into it, thus reducing the rod’s length, and turning the nut in the opposite direction screws both ends of the rod out of the nut, thus increasing the rod’s length. A check nut is sometimes applied to one end of the nut to retain the adjustment. It is used to ad*just the lengths of spark, throttle and brake linkages, the tension rods of trusses, distance rods, etc.
Turning Radius
The radius of the circle which the outside wheels of a car describe when it is turned completely around with the front wheels deflected, by the steering gear, into one or the other of their extreme positions. The greater the angle of lock (see lock, angle of) and the shorter the wheelbase (q. v.) the smaller the turning radius and the less space required in which to manoeuvre a car.
Turntable
A device for turning cars around in a garage, consisting .of a circular platform, flush with the floor, which is supported beneath upon anti-friction bearings, generally several series of balls, so that it and a car which has been run onto it can readily be rotated by hand, and the car be left pointing in any desired direction.
Two Cycle Engine
A gas engine operated upon the two stroke cycle (q. v.). Most such engines are without valves in the common acceptation of the term, gases leaving and entering the working cylinder and pump chamber through ports in the cylinder wall, which are closed and opened by being covered and uncovered by the working surface of the .piston in its travel. In some late designs, however, mechanically operated and automatic valves are adopted. The charge to be admitted to the working cylinder, through the transfer passage (q. v.), is usually pr-ecompressed in the gas-tight crank case by the lower face of the piston or in a special pump chamber acted upon by an extension of the working piston. The displacement of remanent burnt gases from the cylinder and the distribution of the fresh charge therein are facilitated by a deflector plate (q. v.)- Mechanically and as to their ignition (see timer), carburetion, cooling and Lubrication (see lubrication, mixture method), they are similar to four cycle engines. They are built in multicylinder types and in the four cylinder type the cranks are usually set at angular intervals of 90 degrees, thus providing for an overlapping of power impulses and a constant torque. The detail of the manner in which the cycle is carried out is susceptible of considerable variation, and much diversity of design exists. The most common types in commercial use are denned under the following heads.
Two Cycle Engine, Differential Piston Type
A type of two cycle engine equipped with differential pistons and cylinders (see piston, double diameter, and cylinder, double diameter). The larger bore and piston of each cylinder acts as a pump, pre-compressing the charge for transfer to the combustion space of another cylinder, the crank of which is set at 180 degrees with that of the pumping cylinder.
Two Cycle Engine, Distributor Valve Type
A type of two cycle engine, built with two cylinders or a multiple thereof, in which the transfer of the pre-compressed charges to the working cylinders is effected through transfer passages which, as well as the suction passages to the pumping chambers, are controlled by a rotary distributor valve (q. v.), rotated at crankshaft speed by the engine. In a typical form of four cilinder engine of this type, in which the cranks of each pair of cylinders are set in opposition, double diameter pistons are employed (see two cycle engine, differential piston type). The distributor valve alternately establishes communication between the carburetor and the precompression space of a particular cylinder, during the entire downward stroke of its piston and between the said pre-compression space and the transfer passage to the adjacent working cylinder when the piston of the same is near its downward dead centre. The angular relation of the distributor valve to the crankshaft can be varied at the will of the operator so as to delay the instants of transfer of the charges to the working cylinders, when high fuel economy but not maximum power is required.
Two Cycle Engine, Fuel Injected
A form of two cycle engine in which pure air is supplied the working cylinder from the crank case or other source of transfer pressure, and fuel is injected into -the combustion space at the correct instant to form the combustible mixture (see fuel injection). Not in commercial use.
Two Cycle Engine, Rotary Valve Crank Case Admission Type
A type of two cycle engine in which the third port (see two cycle engine, three port type) is dispensed with and in which the charge is admitted from the carburetor to the crank case, previous to its compression therein, and transfer to the working cylinder, through a rotary valve carried by the crankshaft, which opens the passage during nearly the whole upward stroke of the piston and closes it during the down stroke. A disc, with a sector shaped port, is carried by the crankshaft, which registers during the appropriate part of its revolution with a port in the end of the crank case, which gives communication with the carburetor.
Two Cycle Engine, Three Port Type
A two cycle engine, the cylinder wall of which is pierced with three ports, extending around it through considerable arcs, viz.: The melt port B on one side thereof, forming one termination of the transfer passage (q. v.) and, upon the other side, the exhaust port C, the outward edges of these ports registering with the inward edge of the piston when at its outward dead centre. The exhaust port is wider than the inlet port. On one side of the cylinder is the third, or crank case admission port A, the inward edge of which registers with the outward edge of the piston when it is at its inward dead centre. This port is piped to the carburetor. The cycle is as follows: Considering first the outward face of the piston acting upon the gases in the tight. Two crank case, in moving inwardly, nearly to its inward dead centre, the piston has rarified the gases in the crank ‘case by increasing its volume, and, as its outward edge passes the outward edge of port A, gas rushes in therethrough from the carburetor, filling the crank case. As the piston reverses and begins to move outward, port A is closed and the charge, trapped in the crank case, is slightly compressed, which action continues until, late in the outstroke, the inward edge of the piston uncovers inlet port B and the somewhat compressed charge rushes into the working cylinder through the transfer passage, being diverted into a proper direction by deflector plate (q. v. ) D, the exhaust gases meanwhile escaping through exhaust port C, partly under the scavenging (see scavenge) action of the incoming charge. As the piston commences its inward movement, its inward edge closes inlet port B, and, somewhat later, exhaust port C, and the charge trapped in the working cylinder is compressed therein, back of the piston, until the inward dead centre is reached, when the spark is passed, ignition and expansion occur and the piston is forced outward on the working stroke. When its inward edge registers with the inward edge of exhaust port C, the burned gases commence to escape, and a little later, when its inward edge registers with the inward edge of inlet port B, the new charge, previously compressed in the crank case, begins to enter the cylinder most generally used type of two cycle engine.
Two Cycle Engine, Two Port Type
A type of two cycle engine in which the crank case admission port (see two cycle engine, three port type) is dispensed with, gas being drawn into the crank case from the carburetor, through an inwardly opening, suction operated, spring closed poppet valve (see valve, automatic), which opens when the in stroke of the piston has sufficiently rarefied the gases in the crank case and closes when the rarefaction ceases, at or near the beginning of the outstroke. This type is not well fitted for automobile use, but is common in marine practice.
Two Stroke Cycle
The cycle upon which a two (stroke) cycle internal combustion motor is operated, comprising one inward and one outward piston stroke. At the beginning of the outward stroke, the fuel charge, previously compressed behind the piston in the working cylinder, is ignited, expands and does useful work upon the piston, forcing it outward, the products of combustion escaping during the later portion of this stroke and the earlier portion of the inward stroke. During the last part of the outward stroke and the first part of the inward stroke, the next fuel charge, which has meanwhile been somewhat compressed in a communicating pump cylinder, is allowed to expand into the working cylinder, its entrance thereinto assisting in displacing the remanent exihaust gases therefrom and charging the working cylinder for the next combustion. During all but the earlier portion of the inward stroke the charge thus admitted is trapped behind the working piston and is compressed preparatory to being ignited at the end of this stroke. An engine operating upon this cycle does useful work on each outward stroke instead of on each alternate outward stroke, as does a four cycle engine. The outward stroke is primarily a power stroke and the inward stroke a compression stroke, exhaust and admission occurring practically simultaneously during the period when the piston is near its outward dead centre. The charge is always forced into the working cylinder by external energy and not by the suction of the working piston as in a four cycle engine.
