US2334143A - Traffic counting apparatus - Google Patents

Description

Nov. 9, 1943. o. H.'BASQUIN ETAL 2,334,143

TRAFFIC COUNTING APPARATUS Filed Feb. 17, 1941 4 Sheets-Sheet l L U INVENTORS OLIN H. BASQUIN SAMUEL E. ADAIR BY 4/.

ATTORNEY Nov. 9, 1943. o. H. BASQUIN ETAL 3 TRAFFIC COUNTING APPARATUS Filed Feb 17, 1941 Q 4 Sheets-Sheet 2 3a 26 27 19 f 59/ 2 (Q 30 11 flu .L/Ll Ll 77/77 /7 527771707 INVENTORS OLIN H. BASQUIN SAMUEL E. ADAIR BYW ATTORNEY Nov. 9, 1943. o, H, BASQUIN ETAL 2,334,143

TRAFFIC COUNTING APPARATUS Filed Feb. 17. 1941 4 Sheets-Sheet 3 9 1 3, 3 I JP g3 42 INVENTORS OLIN H. BASQUIN SAMUEL E. A DAIR ATTORNEY 1943- o. H. BASQUIN ETAL 2,334,143

TRAFFIC COUNTING APPARATUS Filed Feb. 17, 1941 4 Sheets-Sheet 4! 74 YINVENTORS OLIN H. BASQ-UIN SAMUEL E. ADAIR ATTORNEY Patented Nov. 9, 1943 UNITED STATES PATENT OFFICE TRAFFIC COUNTING APPARATUS Application February 17, 1941, Serial No. 379,256

'7 Claims.

This invention relates to traffic counters and particularly to counters adapted to count vehicular trafllc and, among other objects, aims to provide a reliable and inexpensive counter capable of counting dense and high speed traiflc.

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

In said drawings:

Fig. l is a perspective view, somewhat diagrammatic in character, of counting apparatus and this purpose it is important not only to obtain a picture of trafiic density on a given highway but of such density in relation to traflic density on traific detector installed to count vehicular trafiic on a highway, the counting apparatus being shown on a relatively larger scale;

Fig. 2 is a plan view of the counting apparatus with the cover thrown back to expose the interior mechanism;

Fig. 3 is an elevation of the counter actuating mechanism;

Fig. 4 is a plan section taken from the plane 4-4 of Fig. 3;

Fig. 5 is an elevation of a time control device for controlling the period of operation of the counter;

Fig. 6 is a fragmentary longitudinal section on an enlarged scale of a pneumatic traflic detector.

Fig. '7 is an elevation of mechanism responsive to impulses from the detector for controlling the operation of the counter;

Fig. 8 is a section taken on plane 8-8 of Fig. 7;

Fig. 9 is a section taken from plane 99 of Fig. 8 showing a portion of the diaphragm housing;

Fig. 10 is a view similar to Fig. 7 taken from a plane Ill-l0 of Fig. 8 below the adjusting dial;

Fig. 11 is an enlarged fragmentary sectional view of the diaphragm and diaphragm housing;

Fig. 12 is a section of a portion of the housing taken from the plane l2-I2 of Fig. 9;

Fig. 13 is a sectional view on an enlarged scale taken from the plane l3-l 3 of Fig. 2 showing an adjusting device and dirt collector for the road strip;

Fig. 14 is a similar section of a different form of dirt collecting device;

Fig. 15 is a view on an enlarged scale of the counter operating mechanism shown in Fig. 3; and

Fig. 16 is a double size fragmentary elevation partially in section of a portion of the counter to illustrate the light weight and low inertia counter wheels. Only two counter wheels are illustrated, the others being removed.

One example, among many occasions for counting vehicular traffic, is highway planning. For

neighboring highways. This requires simultaneous counting of trafiic on a plurality of highways. Automatic counting of vehicular trafllc presents peculiar problems not encountered in counting generally. Vehicles travel at widely varying speeds, in difierent directions, and in varying densities. It is not uncommon for several vehicles to pass a counting point simultaneously or practically so. Photo-electric counting devices are wholly impractical when vehicles overlap at the counting point and, therefore, it is practically necessary to employ a detector extending transversely across the road to originate impulses representing passing traflic. Each vehicle, therefore, sets up two impulses in the detector, one for the front and the other for the rear tires. If two vehicles engage the strip simultaneously, two impulses will be lost; and if the interval between impulses is so short as not to allow time for the counter to respond, one impulse will be lost for each failure to respond. Failure to count all vehicles crossing the road detector may result from one or both of two cases: (1) vehicles engaging the detector too nearly simultaneously, as where the vehicles are too nearly abreast or travelling in opposite directions, strike the road strip at too nearly the same instant; (2) vehicles crossing the detector at such high speeds that the duration of the impulse (that is, the time consumed by a tire in crossing the road strip) is too short to cause operation of the counter.

The degree of accuracy of the counter depends, therefore, on (1) the minimum length of the interval between successive impulses necessary for successive counter operations, and (2) the minimum duration of the impulse necessary for counter response. Dense traflic (which is relatively slow moving) produces a high impulse frequency (because a plurality of vehicles travel nearly abreast) but the impulses are each of relatively long duration. High speed trafiic, (which is sparse and generally cannot accompany dense trafiic) produces impulses of very short duration but their frequency is slower than with dense traffic. In other words, high speed traific results in short and, therefore, weaker impulses but long intervals between impulses, and dense traffic in short intervals but relatively stronger impulses. Therefore, the counter must be capable of satisfactory operation both for dense traffic with short intervals and for high speed traffic with short impulses. Sensitivity to one type of trafiic but not to the other would be unsatisfactory in a practical counter.

The illustrative counter is designed for unusually high speed operation. Its maximum speed has not been determined but it has responded to 3600 impulses per minute. At this rate of operation, the interval between successive impulses is V of a second. With present vehicular density and speed, a frequency of 2400 per minute is ample and produces less battery consumption.

In the present instance a pneumatic detector or road tube In is illustrated. The tube is preferably stretched across the roadway and anchored in stretched condition by clamps l I. Its elasticity causes it to return to initial position if displaced by passing vehicles. It is closed at its far end l2 to prevent entry of dirt and moisture. The other end of the tube is operatively connected to an impulse responsive device in the form of a diaphragm [3. In crossing the tube, the vehicle tires create air impulses which displace the diaphragm to close an electric circuit for actuating the counter. Obviously this circuit may also be energized by an electric detector of the type shown in Paver Patent No. 2,163,960 or Basquin Patent No. 2,156,715.

To permit high speed operation, the counter and its operating parts are made small and light in weight. This also makes it possible to operate the counter with small dry cells, thereby greatly reducing the weight and size of the unit as compared with counters requiring the operation of the storage batteries. In the present instance, two small 6 volt dry cells I4 occupying only about 30 cubic inches are employed.

The counter (illustrated in detail in Figs. 3, 4 and is actuated by a small electromagnet l5. Figs. 3 and 4 are drawn to full scale and show the actual size of the counter, its operating mechanism and the electromagnet. In the present case the counter comprises five counting wheels l6 (Fig. 2) representing successive digits. To reduce inertia and to permit high speed operation, preferably all unnecessary auxiliary mechanism, such as all resetting mechanism, is dispensed with. The counter mechanism is conventional and, therefore, need not be illustrated. In the present case, a Veeder type mechanism is employed. The counter wheels are small, being about H inch in diameter and, as illustrated in Fig. 16 at double size, their rotating mass is very low; they weigh only about ,6 ounce each. Even when all five counter wheels move at one time (which occurs only once for each 20,000 impulses, i. e. 10,000

vehicles), the total counter wheel mass is only .176 ounce.

Connected to the counter shaft ll projecting from the counter housing I8 is a 20 tooth ratchet wheel is. The ratchet wheel is advanced one tooth for each impulse, that is, two teeth for each vehicle. The units counter wheel rotates with and at the samerateas the ratchet and carries ten digits. Each revolution (i. e. twenty impulses) of the ratchet wheel and units counter wheel, therefore, represents a count of ten vehicles. The ratchet wheel is advanced in this instance by a lightweight pawl in the form of a light, flexible flat spring 20 connected to the magnet armature 2|. The latter is pivoted at 22 and operates against spring 23. In this instance the spring alone rotates the counter ratchet and the magnet serves merely to retract the pawl and reenergize the spring. This arrangement advantageously makes it possible to devote the major portion of each cycle to the operation of the counter and the minor portion thereof to energizing the spring, which occurs upon energizing of the magnet, the latter inherently being a rapid operation, and because of the small number and light weight of the elements moved may be made to consume only a very small fraction of the entire cycle. In high speed operation the inertia of the counter ratchet and the counter wheels (particularly on counts involving a change from 9 to 0 in one or more denominational orders, thereby requiring the rotation of more than the units counter wheel) is relatively high and it is important, therefore, that as large a proportion as possible of the cycle be devoted to this operation to minimize expenditure of battery energy and to reduce shock. In the present instance, because of the exceedingly rapid operation of the magnet armature, it is possible to devote or more of the cycle to the rotation of the ratchet and counter wheels.

Spring 23 is here shown in the form of a lightweight torsion spring made from steel music wire about a, of an inch in diameter. In order not to impede the speed of the counter, the spring is designed to have a natural period of vibration or oscillation substantially in excess of the maximum frequency of counter impulses. In other words, the spring must be fast and light enough to produce proper operation under the variety of impulses and impulse frequencies encountered. One end 24 of the spring is connected to the bracket 25 on the armature (in this case simply by entering a hole in the bracket), and the other end 26 is connected to a tension adjusting nut 21. The intermediate portion of the spring is coiled about armature pivot shaft 29. By screwing nut 21 up or down on the threaded stud 30, the tension of the spring may be adjusted.

The pawl 20 is likewise made light'in weight to reduce inertia and its end is connected to bracket 25 on the armature. To prevent overdrive (i. e. the advance of more than one ratchet tooth per impulse) a stop represented by the end of an adjusting screw 3| is located in position to engage the leaf spring pawl at the limit of its forward travel and to hold the latter in such position that it prevents further movement of the ratchet wheel. It will be apparent, particularly by reference to Fig. 15, that although the end of screw 3| is located beyond the path of the tips of the ratchet teeth, it is so close to the tips of the teeth that when the spring pawl has advanced the ratchet by one, tooth, it operates in conjunction with the interposed pawl tip to prevent further rotation of the ratchet (see Fig. 15) The spring pawl, 'of course, flexes as it follows the movement of the ratchet teeth. The illustrative pawl and ratchet arrangement is particularly advantageous for high speed as compared with conventional ratcheting mechanisms since parts of the latter are dispensed with, thereby reducing the number and inertia of moving parts to a minimum. A light leaf spring 32 prevents return or reverse travel of the ratchet.

To minimize wear of pawl and ratchet teeth, an adjustable stop 33 is provided to limit upward travel of the armature 2| and spring at the desired point. The stop is here shown in the form of an adjustable screw stud whose end abuts against the stop point 34 on the armature. The stop screw, therefore, assumes the entire impact of the armature and pawl, arising upon stopping of the armature and pawl, relieving the screw 3| of all stress except that of arresting rotation of the ratchet wheel l9 at the desired point.

The maximum speed of operation of the counter operating mechanism may be considerably varied simply by adjusting the tension in torsion spring 23 by means of the adjusting nut 21. Increase of tension in spring 23, of course, increases speed of operation (necessary for dense traflic which produces a rapid sequence of impulses each of relatively long duration); relaxation of the tension reduces speed of operation suitable for high speed trafiic producing impulses of low frequency but of short-duration. However, increase of spring tension involves increase in consumption of battery energy and it is, therefore, desirable not to increase the spring tension beyond the sensitiveness required. For high speed trafllc where the resulting electrical impulses are short and, therefore, comprise less energy, the counter armature should offer a minimum resistance to movement so that it may be attracted in the short time available. Therefore, the tension in spring 23 should be reduced. The reduced spring tension will require longer time for operation of the counter but in dense trafiic the intervals between impulses are longer and it is during these impulses that the rotation of the counter wheels takes place. On the other hand, in dense traiiic where the intervals are short the counter must operate rapidly; hence tension in the spring must be increased to produce faster rotation of the counter wheels. This requires more power but in dense traflic the impulses are longer and, therefore, comprise greater electrical energy. In actual practice for high impulse frequency, it has been found that sensitiveness of the counter to impulses of 2400 per minute is ample.

Displacements of diaphragm |3 in response to impulses close a circuit through the battery H and magnet I5 to operate the counter as aforesaid. As here shown (Figs. 7 to 12), impulses from the road tube III are directed to diaphragm l3 through a diaphragm housing 48. The latter comprises a plate having a fiat surface including an annular margin 4| for determining the normal position of the diaphragm, and a threaded tubular stud 42 to which the road tube is connected. In the present instance, this connection comprises elbow 43 threaded into the stud and entering the end of the road tube. Stud 42 is also externally threaded and carries a nut 44 by means of which the diaphragm housing may be mounted. The diaphragm is held in position by an annular ring 45 screwed to the rim of the housing 40 beyond the edge of the diaphragm and having an inwardly projecting flange 46 lying over the rim of the diaphragm. The latter flange together with the seat 40 for the diaphragm is designed to provide a recess 41 for the margin of the diaphragm which allows a slight clearance around the marginal face and edge of the diaphragm so as not to clamp the latter tightly. In the present instance, this clearance is about .005 of an inch. This clearance not only provides for escape or entrance of air around the diaphragm at a limited rate but avoids permanent stretching or distortion of the diaphragm under the impulses from the road tube or under thermal expansion or contraction of the diaphragm or housing. The illustrative diaphragm is made from a vinyl resin, sold on the market under the name Vinylite; its thickness is about .005 of an inch.

The electric contacts closed by displacement of the diaphragm are advantageously separate from the diaphragm to permit easy replacement of the latter without the necessity for attachment of a contact to the diaphragm itself. In the present case the diaphragm actuated contact 48 is carried by looped flat spring 48 which holds the contact against the face of the diaphragm and resiliently returns the diaphragm to its seat after each displacement. As'here shown, the spring is offset at 58 opposite the passage in stud 42 and is laterally enlarged to about inch to provide a substantially large flat surface in contact with the diaphragm. This distributes pressure over and prevents-distortion of the latter. Contact 48 is located in offset 58 and attached thereto by soldering, riveting, or the like. Spring 49 is advantageously made of phosphor bronze, spring copper, or the like to provide maximum electric conductivity since it serves as the conductor for contact 48.

The opposite or stationary contact 5| is advantageously adjustable to permit adjusting of the contact gap. In this instance, contact 5| is mounted on a metallic screw 52 threaded in a support 53 which electrically insulates it from spring conductor 49. The support is here shown in the form/of a bar of Bakelite, or the like, extending across the diaphragm housing and attached by screws or the like to the ring 45. Screw 52 is provided with a stud 54 carrying a dial 55 graduated to indicate the contact gap in thousandths of an inch. To calibrate the contacts in the first instance, contact 5| is advanced until it engages contact 48. Such engagement is made evident by closing of circuit through magnet l5 and operation of the counter. In this position the dial 58 is set relative to screw 52 to register its zero indication 56 with a stationary index 51. The dial and stud 54 are advantageoulsy adjustably interconnected in this instance by means of knurling or splines 58 on the interior of the dial knob 59 and corresponding splines or knurling on the exterior of stud 54. This permits the former to be lifted and rotated relative to stud 54 and screw 52 toregister zero with the index, and then restored. The splines prevent further relative rotation.

Electrical connection with contact 5| is effected by means of a metal contact strip mounted on bar 53 and having its extremity 8| bear resiliently against the splines 58 on stud 54.- The screw 62 which carries the index mark 51 serves also as a terminal for conductor 63. Conductor 64 for the diaphragm contact 50 leads to a terminal screw 65 also mounted on bar 53 from which a conductor strip 66 leads to spring conductor 48 to which it is attached by one of the screws 61 which connect the conductor spring to bar 53.

Contacts 48 and 5| are preferably made of conventional electrical contact alloys to resist and minimize the burning effect of sparking. In the present instance, the electrical energy re quired to operate the magnet I5 is so small as not to create serious sparking on separation of the contacts and a condenser around the contacts, therefore, is not necessary. For heavier currents, of course, a condenser may be used to protect the contacts.

To prevent accumulation of dust particles between contacts 48 and 5|, the diaphragm housing is advantageously mounted in a vertical position (see Fig. 2). In the present instance, the diaphragm is mounted on the vertical flange B8 of bracket 59 and held firmly by nut 44. As shown in Fig. 2, the electrical circuits are quite simple:

- from the road tube.

impulse whereas the counter, diaphragm and battery being connected in series, in which circuit a manually operated switch 10, is advantageously included.

The diaphragm housing is advantageously provided with a series of passages H (in this case formed in the flat surface against which the diaphragm lies) leading from the central opening 12 to allow lateral travel of the air impulses These passages terminate at the diaphragm seat 4| but, as stated above, the diaphragm is loose in its mounting (there being a clearance of .005 of an inch at its margin) and there is, therefore, opportunity 'for limited,

leakage of air around the diaphragm.

The passages below the diaphragm contribute materially to stabilizing displacement of the diaphragm under varying air impulses. The matter of varying impulses creates a very substantial problem. A slowly moving vehicle crossing the far'end of the road strip Ill sets up a very light a rapidly moving or heavy vehicle crossing the near end of the tube, i. e., close to the counter,- creates a relatively strong impulse. If the contact gap be so small as to respond to light impulses, it is likely to respond also to secondary impulses following a strong impulse. When an impulse is strong, it usually sets up waves in or oscillations of the air column in the road tube and below the diaphragm, causing the latter to be displaced repeatedly with repeated closing of the counter circuit. This repeated closing may be described as a chatter and, of course, register false counts. If the con tact gap be widened to eliminate response to secondary impulses or oscillation of ,the air column, light impulses set up by vehicles crossing the road strip will not be strong enough to close the contacts. The passages under the diaphragm function apparently both to render the diaphragm sensitive to a wide range of impulse strength and to eliminate secondary displacement or chatter following strong impulses. This may not be complete since the underlying theory is not fully understood. However, it is possible that the expansion of the flexible road tube (after a vehicle tire releases it) causes a suction on the diaphragm and this suction is distributed by the passages H over a relatively large area of the diaphragm, thereby promptly reseating the diaphragm in its housing and thereby aiding spring 49 in separating the contacts. The inertia of the diaphragm coupled with the ability for air impulses to escape around the edges of the diaphragm by way of the passages "ll tends to prevent response of the diaphragm to rapid secondary oscillations or waves of the air column. The latter may also differ from primary impulses in the amount of air actually displaced down the tube, the primary impulse being characterized by substantial displacement to which the diaphragm is sensitive even though the strength of ,the impulse be small. Also very strong impulses are similarly reduced. The effect, therefore, is to level out traific created impulses and to damp out or render ineffective rapid secondary oscillations or waves.

Secondary impulses may also be minimized by employing a tube circumferentially reinforced by a non-stretching fabric 15 (Fig. 6). Such fabric may be either molded inside the rubber of the tubing or may line either the inside or outside of the tubing. Its function is to prevent circumferential stretching of the tube under air pressure created by a strong impulse and the subsequent contraction of the tubing to create a secondary impulse. Reinforcement of the tubing against circumferential stretching is not necessary for all installations. For ordinary two lane roads, with a lead tube of substantial length leading from the road to pulses from vehicles are sufliclently alike, and adjustment of the diaphragm contact to effect response to the lighter as well as the stronger impulses is alone sufllcient to avoid chattering.

For wider roads or short lead-in, the fainter impulses coming from which is of larger diameter than the nearer section of the tube. A multiple tubing of this character is illustrated in Fig. 6 wherein the far end ll of the tubing to the right of the center line I! of the road is of compressed by the passage nifies the impulse transmitted to the diaphragm since it is required to pass through the section of tubing having the smaller diameter. Also it is likely that variation in diameter tends to interfere with and damp or waves.

Composite tubing of this character may be inexpensively madesimply by vulcanizlng together tubes of smaller and larger diameter. It is not essential that the bore at the point of juncture be tapered as shown at 19, since the same result should occur even if there be a perceptible offset at the juncture.

In Fig. 13 is illustrated a device which may be employed, if necessary, to minimize variation in impulses reaching the diaphragm. This device comprises a relief valve in the form of a lightweight disc "exposed to impulses from the road tube and adapted to be lifted (if the impulse exceed a predetermined maximum) to permitescape of air through the ports ill in the valve housing 82. In the present instance, the valve housing is provided with nipples l3 and 84, the former to receive the lead in section of the road tube and the latter to receive a supplementary tube 85 (see Fig. 2) leading to the diaphragm nipp1e'43. Normally disc 80 rests upon the valve seat 85 closing the passage to the ports 8|.

relief provided by disc 80 depends upon the height to which it is raised above its seat and this in turn depends upon the strength of the impulse from the road tube. Thus extreme variation' in the strength of the impulses is minimized with the result that they are of more nearly uniform character when reaching the diaphragm. This makes it possible to adjust the diaphragm to be sensitive to the fainter impulses without having an objectionably small contact ga Too small a gap is undesirable for many reasons, among which are: danger of the contact points freezing together, closing contacts by ground vibrations created by passing vehicles, chattering from secondary waves or oscillation, or vibration of the diaphragm.

An adjusting screw 8! is advantageously provided to limit the distance which disc may rise from its seat. Screw 81 is provided with a knurled knob 88 against which a spring catch 89 bears to hold the screw in adjusted position.

In the present instance, the valve housing embodies a dirt trap 80 adapted to receive particles of loose rubber and dirt from the road tube and the counter, the imout secondary oscillations and outlet nipples to prevei their entry into the diaphragm housing. This trap and 84. The bottom of the trap is closed by a removable screw plug may be removed.

In Fig. 14 there is illustrated another form of dirt trap which is used whenever there 15 no need for a relief valve. In this instance, the inlet 92 and 93 are offset at the dirt collecting chamber 94.

It should be understood that the relief valve is made by offsetting nipples 83 9| by means of which dirt as well as the dual diameter tube are not necessary for the common two lane highway, the diaphragm mechanism being capable of functioning under the range of impulse variations occurring on ordinary highways. However, for unusual conditions, as where the lead in is very short (that is, the counter is very close to the highway) or the highway is very wide, or the traffic is considerably varied both as regards speed and character of vehicles, i. e. passenger cars, it may be desirable to employ either a composite road tube or the relief valve or both.

The length of the lead in 9, that is, the length of the tube from the edge of the highway to the counter (see Fig. 1), is important as regards variation in strength of impulses reaching the diaphragm. If the counter be closely adjacent the curb (as is sometimes necessary in cities) the impulse from vehicles crossing the tube adjacent the counter are very strong and must be reduced by a relief valve to permit a setting of the contact gap responsive to the fainter impulses from the far end of the tube and, at the same time, to eliminate chattering from strong impulses. The composite tube illustrated in Fig. 6 may also be used to amplify the fainter impulses. To avoid the necessity for delicate adjustment of the con-. tact gap, it is desirable to employ a lead in tube at least ten feet in length. The lead in tube need not be of the same character as the detector tube but preferably it should have approximately the same inside diameter. A non-flexible lead in tube, such as copper tubing, has been found helpful in damping down secondary oscillations and waves and in softening very strong impulses, and

it may advantageously be used for this purpose if conditions be acute, either alone or in conjunction with a relief valve and composite road tube.

In making trafiic surveys which depend upon counting trailic simultaneously on a plurality of neighboring highways, the counter may be equipped with a time control device by means of which all counters may be placed in operation simultaneously and rendered inoperative simultaneously. This permits a simultaneous count at a plurality of points at any predetermined period of the day, and readings of the several counters may be made at the operators convenience at any time during the remainder of the day.

Any standard time control device may be employed for this purpose. The illustrative device is a Minneapolis-Honeywell control, originally designed for control of heating systems. Since 'this device is an article of commerce and its operation well understood, it need not be described in detail. It will be sufiicient here to note that the control cams 95 and 96 (Fig. 5) are rotated by the clock, making one rotation for each twenty-four hours. These cams successively operate a trip lever 91 which inaugurates rotation of the switch cam 98. The latter makes one-half revolution for each operation of trip lever 91, either to close switch 99, in this case a heavy trucks and light micro-switch (and hold the same closed as indicated in dotted lines), or to release the switch and permit it to remain open until the lever is again tripped. Control cams 95 and 96 may be angularly adjusted by reference to the time dial to set the counter in operation at any desired hour and to interrupt its operation at any desired hour. As illustrated in Fig. 2, the time device It! is placed in series with the battery, counter, diaphragm, and manually controlled switch 10.

The entire unit is enclosed inside a housing I02 having a hinged cover I03 having a sight glass [04 adapted to register with the counter to permit reading of the counter without opening the lid.

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 sub-combinations.

The subject-matter involving the pneumatic system in the apparatus and illustrated in Figs. 6 to 14 is claimed in our copending application Serial No. 412,558.

Having described our invention, we claim:

1. In apparatus for counting high speed vehicular traflic, the combination comprising an electromagnet adapted to be, energized .by passing vehicles, a ratchet wheel mounted beyond an end of the electromagnet for driving a series of counter wheels, an armature having an end pivoted at one side ofthe electromagnet and between the electromagnet and the'ratchet wheel and having connected to its other end a resilient pawl projecting generally toward the ratchet wheel in the direction of movement of said armature away from said electromagnet, said pawl being adapted to be thrust against said ratchet wheel to rotate the same upon movement of said armature away from said electromagnet, and a spring having one end connected to said armature to bias the armature away from the electromagnet, said spring having inherently less inertia than the ratchet and counter wheels so that very brief energization of the electromagnet is effective to move the pawl away from the ratchet wheel and tension the spring and subsequent deenergization of the electromagnet allows the tensioned spring to advance the pawl and rotate the ratchet wheel in the interval preceding the next energization, whereby the major time portion of each complete cycle of the armature movement is devoted to operating the ratchet and counter wheels.

2. In apparatus for counting high speed Vehicular traffic, the combination comprising an electromagnet adapted to be energized by passing vehicles, a ratchet wheel mounted beyond an end of the electromagnet for driving a series of counter wheels, an armature having one end pivoted at one side of the electromagnet and between the electromagnet and the ratchet wheel, a pawl mounted on said armature and projecting toward and engageable with said ratchet wheel in a direction generally parallel with the attractive counter wheels so that very brief energization of the electromagnet is effective to retract the armature and tension the torsion spring and subsequent deenergization of the electromagnet allows the tensioned spring to advance the pawl and rotate the ratchet wheel in the interval preceding the next energization, whereby the major time portion of each complete cycle of the armature movement is devoted to operating the ratchet and counter wheels, and means connected with the other end of said torsion spring for varying the tension therein to adjust the speed of advance of said pawl'to the character of the passing trafflc.

3. In apparatus for counting high speed vehicular traflic, the combination comprising an electromagnet adapted to be energized by passing vehicles, a ratchet wheel mounted beyond an end of the electromagnet for driving a series of counter wheels, an armature having one end pivoted at one side of the electromagnet and between the electromagnet and the ratchet wheel, a pawl mounted on said armature and projecting toward and engageable with said ratchet wheel in a direction generally parallel with the attractive force of said electromagnet on said armature and adapted to rotate said ratchet wheel upon movement of said armature away from the electromagnet, a torsion spring having one end connected with said armature to bias the armature away from the electromagnet, said spring having inherently less inertia than the ratchet and counter wheels so that very brief energization of the electromagnet is efiective to retract the armature and tension the torsion spring and subsequent deenergization of the electromagnet allows the ten sioned spring to advance the pawl and rotate the ratchet wheel in the interval preceding the next energization, whereby the major time portion of each complete cycle of the armature movement is devoted to operating the ratchet and counter wheels, and a stop independent of said ratchet wheel adapted to limit the movement of said armature and pawl away from said electromagnet.

4. In apparatus for counting high speed vehicular trafiic, the combination comprising an electromagnet-adapted to be energized by passing vehicles, a ratchet wheel mounted beyond an end of the electromagnet for driving a series of counter wheels, an armature having an end pivoted at one side of the electromagnet and between the elec tromagnet and the other end portion ratchet yvheel and having at its a bracket arm projecting generally toward the ratchet wheel, a resilient pawl mounted on said arm and engageable with the ratchet wheel, a torsion spring having its intermediate portion wrapped around the armature pivot and having one end secured to the bracket arm and its other end extending beyond the bracket arm, a stud mounted generally parallel to the core of the electromagnet, and a nut threaded on the stud and carrying said other end of the torsion spring for adjusting the tension thereof, whereby the armature is adjustably biased away from the electromagnet and energization of the electromagnet tensions the torsion spring and the pawl advances the ratchet wheel upon deenergization of the electromagnet.

6. In apparatus for counting high speed vehicular trailic, the combination comprising a frame having a pairoi spaced, parallel, outstanding ears, an electromagnet adapted to be energized by passing vehicles mounted on the lower ear and extending toward the upper ear, counter mechanism including a ratchet wheel mounted on the upper ear, an armature having one end pivoted on an axis fixed relatively to the frame between the electromagnet and the upper ear and having at its other end portion a bracket arm projecting toward the upper ear, a resilient pawl carried by said arm and engageable with the ratchet wheel, a torsion spring having its intermediate portion wrapped around the armature pivot and having one end secured to the bracket arm, and its other end extending beyond the bracket arm, a stud extending from the upper ear toward the lower ear, and a nut threaded on the stud and carrying said other end of the torsion spring for adjusting the tension thereof. whereby the armature is adjustably biased away from the electromagnet and energization of the electromagnet tensions the torsion spring and the pawl advances the ratchet wheel upon deenergization of the electromagnet.

7. In apparatus for counting high speed vehicular traffic, the combination comprising a frame having a pair of spaced, parallel, outstanding ears, an electromagnet adapted to be energized by passing vehicles mounted on the lower ear and extending toward the upper ear, counter mechanism including a ratchet wheel mounted on the upper ear, an armature having one end pivoted on an axis fixed relatively to the frame between the electromagnet and the upper ear and having at its other end portion a bracket arm projecting toward the upper ear, a resilient pawl carried by said arm and engageable with the ratchet wheel, a torsion spring having its intermediate portion wrapped around the armature pivot and having one end secured to the bracket arm and its other end extending beyond the bracket arm, a fixed stud extending from the upper ear toward the lower ear, a nut threaded on said stud and carrying said other end of the torsion spring for adjusting the tension thereof, whereby the armature is adjustably biased away from the electromagnet and energization of the electromagnet tensions the torsion spring and the pawl advances the ratchet wheel upon deenergization of the electromagnet, and a stud adjustably mounted in the upper ear and extending toward the lower ear constituting a stop for the armature.

OLIN H. BASQUIN. SAMUEL E. ADAIR.

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