US2269501A - Traffic counting apparatus - Google Patents

Description

Ja -12., 1942. w ILE 2,269,501

TRAFFIC COUNTING APP ARATUS Filed Aug. 19, 1937 2 Sheets-Sheet l INVENTOR GEORGE G. WILEY BYW G.

ATTORNEY Jan. 13, 1942. G. G. WILEY 2,269,501

TRAFFIC COUNTING APPARATUS Filed Aug. 19, 1937 2 Sheets-Sheet 2 i l l a! iiiii igni GEORGE G. WILEY ATTORNEY BYWQW Patented Jan. 13, 1942 TRAFFIC COUNTING APPARATUS George G. Wiley, Chicago, Ill., assignor to Streeter-Amet Company, Chicago, 111., a corporation of Illinois Application August 19, 1937, Serial N 0. 159,877

3 Claims.

This invention relates to apparatus for registering the transitions of units such, for example, as determining traffic flow, and among other objects aims to provide counting apparatus capable of counting rapidly moving vehicles or other units to be registered or counted.

The nature of the invention may be readily understood by reference to one illustrative construction embodying the invention and shown in the accompanying drawings.

In said drawings:

Fig. 1 is a front elevation of counting and recording apparatus removed from its enclosing housing;

Fig. 2 is a rear elevation thereof;

Fig. 3 is an elevation taken approximately from the plane 3-3' of Fig. 2, showing a detail of the tape actuating and rerolling mechanism;

Fig. 4 is a cross section taken on the plane 4-4 of Fig. 3;

Fig. 5 is a section taken on the plane 5-5 of Fig. 3, showing a detail of the supporting device for the tape driving roll;

Fig. 6 is an elevation taken approximately from the plane 6-6 of Fig. 2, showing details of the printing hammer and its associated mechanism;

Fig. '7 is a wiring diagram of the electric circuits in the apparatus; and

Fig. 8 is a plan view of a specimen of the record tape.

The invention is here shown embodied in portable apparatus electrically actuated by the wheels of moving vehicles. The counting of rapidly moving vehicular traffic such as is found on many highways, both in cities and. elsewhere, presents a special problem which has not heretofore been solved by mechanical means actuated by contact of the vehicle tires. A vehicle traveling fifty miles an hour, for example, would strike a road strip or other wheel operated actuating device, twice with great rapidity, about one-eighth of a second being the interval between the front and rear wheel contacts. The problem of counting or recording such rapid impulses is further complicated by the circumstance that on many highways the Vehicles travel in a plurality of lanes and that for wide highways the contact strip may approximate 100 feet in length. The electric circuit, including the contact strip, will therefore vary greatly in length, depending upon whether the vehicle engages the strip near its inner or near its outer end; and, since the metallic contact strips have relatively low conductivity (being made from a material, such as Swedish blue steel, capable of resisting permanent deformation under the heavy pressure imposed thereon by vehicles such as loaded trucks), the resistance of the electric circuit greatly varies. The effect of variation in resistance is particularly pronounced in low voltage circuits (from six to twelve volts) to which portable trai'fic counting apparatus carrying its own current supply is practically limited.

However, as will presently appear, the illustrative apparatus is not limited to use with electric road strips, but may advantageously be used in connection with other devices actuated by vehicles or other units (including people) to be counted.

To counteract the effect of the high and varying resistance in the road strip circuit, the recording apparatus embodies a high resistance, high speed relay in the road strip circuit which requires only light impulse for its operation, and which in turn provide a circuit at low and uniform resistance (and not including the road strip) for operating the counting apparatus. The latter requires a substantial amount of current for its operation and a lower period for its operation than is normally provided by the road strip circuit alone. The current supply for the counter is not therefore affected either by the resistance of the road strip or by the point in the road strip where the contact is made. If the counting apparatus were operated only by the circuit including the road strip, a voltage supply high enough to operate with maximum road strip resistance would be required. In many cases, this would involve a voltage which could not be practicably supplied by portable apparatus. On the other hand, the voltage would be much too high for cases where contact was made near the inner end of the road strip, thereby very materially reducing the resistance of the circuit with the result that an excessively high current would be sent through the counting apparatus.

The relay coil requiring only very small current for its Operation can be designed with a sufficiently high resistance not to be influenced by variations in road strip resistance. Moreover, requiring little power for its operation, it may be designed with a very low reactance, and therefore will operate much more rapidly than the magnet for the counting apparatus, which because of the high power which it must develop, requires a relatively high current, and a correspondingly higher reactance.

The illustrative registering apparatus (which is here represented by a counting apparatus) is also advantageously provided with means for maintaining its operating current independently of the relay in the impulse circuit, thereby utilizing the time consumed in opening the impulse circuit relay, for completion of the counting operation. Contrary to usual experience involvin relay circuits, the present arrangement has materially increased the speed of operation of the registering apparatus. For example, the apparatus is capable of a speed of twenty-six complete cycles of its operating magnet per second. With this speed, the apparatus could operatively receive the two impulses (for front and rear wheels of a passing vehicle) necessary to count a vehicle traveling approximately 150 miles per hour, or it could count a plurality of cars passing over the road strip at the rate of thirteen per second. Use of the relay circuits, as presently described, has resulted in doubling or even tripling the speed of the apparatus. The apparatus is therefore particularly adapted for operation with rapidly delivered and light impulses whetherthe impulses are for a road strip or some other device.

The illustrative apparatus is also provided with means for opening the counter circuit after each cycle of the counter magnet, independently of the relay, thereby protecting the counter circuit (which draws a relatively heavy current) against damage in the event of a short circuit in the road strip, or in the event a vehicle comes to rest with a wheel upon the road strip. This protective means, which in this case is in the form of a magnetically operated switch or relay,

also prevents battery drain. The protective relay coil itself draws negligible current, and even though the relay circuit is closed for prolonged periods because of short circuit or otherwise,

the relay coil will not overheat and the battery will not be exhausted.

The counting apparatus in this instance comprises a plurality of printing counting wheels 20 representing the successive denominational orders of the counter. may be varied depending upon the desired capacity of the counter. Since th latter, in this instance, records the count at intervals (one or more times each hour) which are much shorter than that required to exhaust the capacity of a four digit counter, it is unnecessary to provide large capacity in the counter. A comparison of the periodic records would reveal how often the counter capacity had been reached (see Fig. 8).

The counter is actuated by a counter coil Cc, in this case through a pair of oscillating armatures 2| carrying rocking arms 22 connected in tandem by link 23. One arm 22 is in bell crank form, the other arm 24 of which is connected to the counter operating link 25. The details of the counter wheel operating mechanism while not material here are disclosed in co-pending Haegele et al. application, Serial No. 109,422. It will be sufiicient to note the operating mechanism is designed to require two impulses (for front and rear vehicle wheels) for each operation of the units printing wheel, i, e., to register a single vehicle count, and that the twin oscillating armatures operate both with great rapidity and with sufficient power to satisfy maximum demands of the counter. The counter power demands vary, depending upon how many counter Wheels are turned at a given impulse. For example, the counting operation following The number of wheels a record of 9999 involves the greatest power demands, since all four wheels must be rotated in setting the wheels to the next or 0000 position.

The periodic record of the count is in this instance made upon a record tape supplied from a tape roll 3| and guided across the printing wheels in printing position, i. e., opposite the printing hammer 32. After passing beyond the tape guides 33 and 34, the tape passes over the tape driving roll 35 whose teeth 36 mesh with marginal perforations previously formed in the tape, and by means of which the tape is positively and periodically advanced. The tape roll 35 is driven from power shaft 37 at a uniform and predetermined rate. The shaft 31 may advantageously be, and in this instanc is, clock driven. The clock 38 (see Fig, 1) is here shown as a double spring power clock of a type which may be purchased on the open market and which is deslgned to supply a surplus of power which may be utilized in operating various time-com trolled devices. The clock is preferably an eightday clock by which the apparatus may be operated for a week or eight days without attention. If desired, an electric clock, or other constantly rotating electric means which will operate for an indefinite period (depending upon the source of power supply), may be employed.

From the tape-driving roll, the tape is advantageously connected with a rewind roll 39 driven by the clock through a spring belt 40 which is adapted to slip on its driving pulleys when, due to the building up in size of the rewound roll of tape, the rate of rotation of the driving shaft is greater than that required for rewinding the tape. The tape is Wound upon a removable core 4| which may be withdrawn from the rewinding shaft to remove the rewound tape roll at any desired time.

In the present apparatus, the tape is provided with the time records 42 previously printed directly thereon at the proper intervals which represent the rate of travel of the tape during the designated time interval. In adjusting the tape in the apparatus, it may be synchronized with the time of day, either by meshing it properly on the teeth 36 of the driving roll, or by rotating the driving roll 35 until the time represented by the position of the tape opposite printing position corresponds with the time of day. For this and other purposes presently described the tape shaft 35 may be rotated independently of the drive shaft 31 through a clutch here shown (Figs. 3 and 4) in the form of a pair of flanges 44 and 45 (carried by the respective shafts), one flange containing a series of twelve equally spaced perforations 4B (representing every five minutes of an hour), and the other carrying a pin 41 adapted to enter one of the aforesaid perforations. By withdrawing the roll 35 longitudinally until the pin 41 clears the flange 45, the roll may be rotated relatively to the drive shaft 37 to synchronize the clock operated functions, presently described, with the clock. Thereafter, the roll is moved inwardly until the flanges are in contact and the pin 41 enters one of the perforations. The roll is normally held in connected position by a spring 48 carried by a roll supporting bracket 49. Shaft 37 advantageously projects beyond flange 44 and into tape shaft 35 (see dotted lines in Fig. 3) to provide a support for the inner end of the latter.

It is not essential that the driving mechanism be provided with clock hands or clock dialsince it is necessary simply to adjust the tape so that the correct time record is in register with the printing position.

Printing ink is in the present instance provided by inking ribbon 5| drawn from ribbon roll 52 and rewound upon ribbon roll 53 after it has passed across ribbon guides 54.

The printing hammer 32 is of such length as to extend across the entire series of printing wheels. It is here shown carried by a pair of guide rods 55 operating in a bracket 56. Light springs 51 normally hold the printing hammer in retracted position. The printing hammer itself is made of some resilient material, such as rubber, and is advantageously faced with a covering of thin sheet metal 58 which protects the material of the hammer against the deteriorating action of the chemicals carried in the ink ribbon. Printing hammer actuating mechanism is here shown in the form of a magnet coil Po which operates a hinged armature 59 from which extends an arm 60 bearing upon the top of the printing hammer. Springs 51 are sufficient to elevate the printing hammer and the armature 59 when the magnet P is deenergized.

The operating circuits for the counter coil Co and printing magnet Po are diagrammatically illustrated in Fig. 7. Such circuits include a protective relay R1 and the holding or counter operating relay R2. Relay R1 carries opposed switch contacts S1 and S between which is an armature operated switch contact. When the relay R1 is energized, contacts S5 are closed. In deenergized or normal condition, contacts S1 are closed. Relay R2 carries a single pair of normally open contacts S2 which are closed when the relay is energized. The latter relay is in circuit with the road strip RS and the source of electric power, which in this instance, is advantageously a storage battery B.

The counter coil Cc is also advantageously connected in a parallel circuit to the road strip RS so as to take advantage of the time interval (however short) required for energizing relay R2 which then sets up, as presently described, a second or holding circuit which supplies current to the counter coil Cc directly and independently of the road strip RS. Thus, when the road strip is depressed by a vehicle, relay R2 and counter coil Cc are immediately energized. The circuit first established passes from the positive side of the battery through the road strip, contacts S1 (which are normally closed) and thence in parallel circuits through both R2 and Co to the negative side of the battery. Energization of the holding relay R2 closes contact S2 which establishes the aforesaid second or direct circuit (independent of the road strip) through the counter coil Cc, passing from the positive side of the battery through contacts S2 and S3 to counter coil Cc and thence to the negative side of the battery.

Contacts S3 (see Fig. 2) are associated with the counter operating mechanism and operated thereby. In this instance, contacts S4 are closed and S3 opened in sequence by a plunger 65 which operates a spring element 66 carrying the intervening contact elements. The plunger 65 is engaged by the armature arm 22 upon completion of the active portion of the counter cycle. This occurs, in the present case, when the counter coil C is energized and its armatures oscillate tothe left (Fig. 2). At the completion of such stroke, arm 22 engages plunger 65 and efiects the closing of contacts S4. Upon slight further movement, contacts S3 are open. This sequence of operation may be effected by proper adjustment of the spring element 6'! and 68 relative to spring 66.

The foregoing double circuits insure the maintenance of current through counter coil Co for the maximum available time and independently of the length of the interval during which the road strip is depressed.

The opening of contacts S3 breaks the circuit through holding relay R2 and counter coil Cc which has now completed its active operation. The closing of contacts S4 complete a circuit through and energizes the protective relay R1. Such circuit extends from the positive side of the battery through contacts S2 (which are still closed since R2 is not deenergized until after contacts S4 are closed), through contacts S4 to R1 and to the negative side of the battery. Energization of R1 opens contacts S1 and closes contacts S5, thereby breaking connection between the road strip on the one hand and counter coil Cc and relay R2 on the other.

Relay R1 is ordinarily only momentarily energized inasmuch as plunger 65 is practically instantaneously released (upon return travel of the counter coil armatures under the action of spring 69) thereby opening contacts S4. However, if the closing of the road strip contact is prolonged as would be the case with a short circuit, or where a vehicle or other object remained on the road strip, relay R1 would remain energized by a circuit extending from the positive side of the battery through the road strip, through contacts S5, relay R1 and to the negative side of the battery. So long as the protective relay R1 remains energized, contacts S1 and S2 cannot be closed, thereby preventing any further or continued energization of the counter coil Co or relay R2, and consequent depletion of the battery and overheating of coil Cc. Relay R1 has a relatively high resistance, thereby drawing a very low current, and while it may remain energized for an extended period because of a short circuit or otherwise, the battery would not be depleted.

The printing hammer is, of course, operated at intervals corresponding to the time interval printed on the record tape and when such printed time registers with printing position (see Fig. 8). In the present case, a record is made once each hour, or once for each revolution of the driving roll 35. The driving roll may advantageously be used therefore to close the circuit through the printer coil PC; and for that purpose is here shown provided with a single projection 10 (Figs. 2 and 3) adapted once each revolution to make contact with an insulated electric contact S6 resiliently supported by the member H in the path of the projection 70. The engagement of the projection in with the contact Ss establishes a circuit from the battery through contact Se and projection 10 (the latter being grounded) through contacts S7 (then closed) to the printing coil Pc (see Fig 7). The printing hammer is thereby depressed to imprint a record.

An index 50 (Fig. 2) is advantageously placed on the driving roll 35 to assist in synchronizing the roll shaft and its switch operating and other devices with the clock. When the clutch is disengaged, the index is rotated until it aligns with the hour hand. In clocks of this type, it is generally not possible to rotate the drive shaft 31 by means of the clock hands.

As the hammer is about to strike the tape, it actuates a circuit breaker connected with the printing coil Po. Actual breaking of the printing coil circuit is delayed, as presently described, until the instant of impact so as to give the printing hammer opportunity to attain its maximum momentum, but the circuit is broken at this instant so as not to hold the printing hammer against or return it after rebound to the printing ribbon. On the rebound the hammer is held in elevated position by springs 57.

The circuit breaking device is here shown cornprising a latch 72 pivoted at 73 and carrying an arm id projecting into the path of and depressed by the printing hammer as it approaches the end of its downward stroke. Depression of the latch, as aforesaid, releases a movable contact arm '55 pivoted at 16 and carrying a resilient element i! which constitutes one of the contact elements S7 and which, in latched position, is held in electrical contact with an insulated stationary contact 78 constituting the stationary contact S7. On release, contact arm falls breaking contact S7, and opening the circuit through the printer coil P0. The resilient support 11 for movable contact S7 is designed to hold it against stationary contact S1 for a short time after latch '52 has been tripped, thus maintaining the circuit through the printing coil Po until the instant of impact. The circuit through the solenoid is thus broken, even though projection 10 has not passed beyond engagement with contact Se. After the latter contacts are separated by continued rotation of the roll 35, the circuit breaker is reset by a projection 19 carried on roll 35. This engages and depresses the opposite extremity 86 of arm '15 to elevate the latter to its latching point, latch 12 being drawn inwardly by spring 8 i.

To prevent rotation of any of the type wheels 2?) during the instant of printing hammer impact (and thereby avoid smearing the printed record) the printing coil circuit is in this instance opened during operation of the counter. This be advantageously effected by providing relay R2 with a pair of normally closed contacts S8 which are opened only when R2 is energized.

Contacts S8 are connected in the printing coil circuit (see Fig. 7). The means may of course be employed for preventing operation of the printer under these circumstances. The means shown is merely illustrative.

If records be desired oftener than one per hour,

a plurality of projections 10 will be required at appropriate time intervals on roll 35 and the corresponding number of projections 59 will be required to reset the circuit breaking arm 15 after each operation of the printing hammer.

The driving roll 35 may also advantageously carry a projection 82 (Fig. 3) for periodically advancing the printing ribbon by giving its reminding roll 5-3 a partial turn. The latter is shown provided with ratchet teeth 83 which lie in the path of and are engaged once each revolut on of the roll 35 by projection 82. A check pawl is here shown in engagement with the ratchet to prevent reverse rotation thereof.

Condensers 85 Fig. 1) diagrammatically illustrated in the conventional manner in the diaof Fig. 7 are advantageously placed across contacts through which the relatively heavy counter coil current passes.

Obviously, the invention is not limited to the details of the illustrative apparatus since these may be variously modified. Moreover? it is not indispensable that all features of.the invention be used conjointly since various features may be used to advantage in different combinations and subcombinations. For example: While the counting apparatus and its operating circuits is particularly advantageous in conjunction with road strips of the character described, it also has special utility for counting or registering the passing of units of any character and regardless of the manner in which the electric impulses are created by the passing units.

Having described my invention, I claim:

1. 'Irafii-c counting apparatus adapted to count high speed traflic comprising in combination an electrical device responsive to the passage of the vehicle and including an impulse circuit momentarily closed by the passage of the vehicle, electrically actuated counting apparatus controlled by said impulse circuit and responsive to successive impulses from said circuit, a source of electric, current for said counting apparatus, a low resistance holding circuit including said current source and counting apparatus, means controlled by said electrical device for closing said holding circuit to maintain said counting apparatus energized independently of said impulse circuit until completion of the operation of the counting apparatus, a protective switch in said holding circuit, and means including a high resistance relay for opening said switch adapted to be energized during the operation of said apparatus to prevent prolonged flow of current through said holding circuit.

2. Traflic counting apparatus adapted to count lugh speed traffic comprising in combination an electrical device responsive to the passage of a vehicle and including an impulse circuit momentarily closed by the passage of a vehicle, electrically actuated counting apparatus controlled by said impulse circuit, a battery for supplying current to said counting apparatus, a counter holding circuit including said battery and counting apparatus, means including a relay energized by said impulse circuit for closing said holding circuit and for holding the same closed after opening of said impulse circuit, a protective relay controlling supply of current to said counting apparatus, and means for operating said protective relay in response to an impulse from said impulse circuit to prevent continued supply of current to said counting apparatus in the event of a short circuit in said impulse circuit.

3. Traffic counting apparatus adapted to count high speed trafiic comprising in combination an electrical device responsive to the passage of the vehicle and including an impulse circuit momentarily closed by the passage of the vehicle,

electrically actuated counting apparatus controlled by said impulse circuit and responsive to successive impulses from said circuit, a source of electric current for said counting apparatus, a low resistance holding circuit including said current source and counting apparatus, means controlled by said electrical device for closing said holding circuit to maintain said counting apparatus energized independently of said impulse circuit until completion of the operation of the counting apparatus, a high resistance relay having a switch in said holding circuit adapted to be opened upon energization of said high resistance relay, and a protective circuit means for energizing said relay to prevent prolonged closing of said holding circuit.

GEORGE G. WILEY.

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