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Publication numberUS3492428 A
Publication typeGrant
Publication dateJan 27, 1970
Filing dateSep 8, 1966
Priority dateSep 8, 1966
Publication numberUS 3492428 A, US 3492428A, US-A-3492428, US3492428 A, US3492428A
InventorsHavs Carroll D, Redick Thomas E, Stokes Rembert R
Original AssigneeBell Telephone Labor Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Coin level indicator for coin operated apparatus
US 3492428 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

Jan. 27, 1970 c. o. HAYS ETAL 3,492,428

COIN LEVEL INDICATOR FOR COIN OPERATED APPARATUS Filed Sept. 8, 1966 2 Sheets-Sheet l m #:1 W6 A m m 5 m J P K m m L m Mm N LC H E!\ WE y EA NL ME IF R L L R ME 07K C0 GD. HAYS /Nl EN7DR 71E. RED/CK ATTORA/EV Jan. 27, 1970 c. o. HAYS T L 3,492,428 7 -COIN LEVEL INDICATOR FOR COIN OPERATED APPARATUS Fil'ed Sept. 8, 1966 2 Sheets-Sheet 2 United States Patent Ofitice 3,492,428 Patented Jan. 27, 1970 3,492,428 COIN LEVEL INDICATOR FOR COIN OPERATED APPARATUS Carroll D. Hays, Brownsburg, and Thomas E. Redick,

Indianapolis, Ind., and Rembert R. Stokes, Middletown, N.J., assignors to Bell Telephone Laboratories, Incorporated, Murray Hill, Berkeley Heights, N.J., a corporation of New York Filed Sept. 8, 1966, Ser. No. 577,958 Int. Cl. H04m 17/02 US. Cl. 1796.4 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to telemetering systems and more particularly to arrangements for sensing and indicating to a remote location a particular level of collection in the cash receptacle of coin operated apparatus.

A disadvantage share by virtually all coin operated devices from vending machines to telephones is that unpredictable usage patterns make it impossible to establish a fully eflicient schedule of cash collections. Collections made too frequently fail to take advantage of the full capacity of the cash receptacle and accordingly, are economically wasteful in terms of man hours spent by the human route collectors. On the other hand, collections made too infrequently are at least equally undesirable in that full cash boxes may result in damaged or inoperative equipment that causes customer dissatisfaction and loss of revenue.

It has long been realized that the problems indicated could be met readily by the use of a telemetering system that has the capability of Sensing when collected coins fill some preselected substantial fraction of the cash receptacle and the capability of transmitting to some remote control point a suitable signal indicia of this condition. With most coin operated apparatus the cost of providing a communication channel makes any form of a telemetering system prohibitively expensive. In the case of coin telephones, however, a communication channel in the form of telephone lines is available at no extra cost. Understandably, a substantial portion of the prior art in this area lies in the field of coin operated telephones. Patent 1,571,692 issued to P. G. T. DeVilliers. Feb. 2, 1926 is illustrative.

A number of prior art arrangements rely on completing a conducting path to ground through the accumulated coins as soon as the coins reach some predetermined level in the box. It is known, for example, to employ a conductor in the form of a probe which is mounted through one side of the cash box and which protrudes into the approximate center of the box. When the apex of the normally conical coin stack contacts the probe, a short circuit path to ground, which may be the bottom of the box, is completed through the coins. The coins tend to shift around slightly, however, with each additional deposit. This condition, coupled with the comparatively very limited conducting area of the probe, tends to make the short circuit path intermittent for some undertermined period and therefore unreliable as an indicator of the level of the accumulated coins. Additionally, one or more coins at the top of the stack are often supported in an edgewise position by leaning against the probe, causing a premature signal. Subsequent deposits tend to knock the leaning coins down, adding further to the unreliability of the shorting path.

Accordingly, a broad object of the invention is to increase the efiiciency of collecting accumulated deposits of coins from coin operated apparatus.

A more specific object is to increase the reliability of coin level detecting arrangements.

Another object is to avoid any reduction in the physical security of a coin receptacle resulting from the installation of a coin level detecting system.

These and other objects are achieved in accordance with the principles of the invention by the utilization of a substantially fiat dual element sensor plate that includes a signal plate and a ground plate separated by an insulating plate. The ground plate is clipped flat against the rear wall of the coin receptacle and is in electrically conductive contact with the receptacle cover. The cover in turn bears against a grounded portion of the surrounding vault. The ground plate extends into the lower portion of the coin receptacle and its relatively large surface is exposed to contact with deposited coins as soon as the coin stack starts to build. The signal plate and insulating plate are affixed to the upper portion of the ground plate at a preselected level and triggering of a monitoring circuit occurs whenever the coin level is sufiicient to establish a short circuit path through the coins from the signal plate to the ground plate.

One key aspect of the invention relates to the size of the two coin contacting members, the signal plate and the ground plate, which cover a substantial portion of one wall of the coin receptacle in contrast to prior art arrangements that utilize cylindrical probes. Not only is contact reliability enhanced by increasing the contact area with the deposited coins by several orders of magnitude, but also, the reduction in coin storage capacity attendant to the use of probes is virtually eliminated.

In accordance with a particular feature of the invention the lower edge of the signal plate is bent outwardly forming a ledge to facilitate good contact pressure between the coins and the signal plate. The underside of the ledge is protected from conducting contact with the coin stack by a similar ledge formed by the insulating plate. As a result, signaling reliability is enhanced when the coin level exceeds the preselected level and complete protection is provided against those temporary and therefore unrealiable conducting paths that might otherwise be established between the signal plate and the ground plate by edge-balanced or leaning coins.

Another feature of the invention pertains to the relation between the coin level detector apparatus and the coin telephone control circuitry that ensures complete isolation of the detector apparatus whenever uncollected coins are present in the coin hopper. This arrangement avoids the possibility of any interference with normal coin control by the coin level detector apparatus.

One particularly attractive feature relates to the ease with which a conventional coin telephone may be moditied to include a coin level detection arrangement in accordance with the invention. The necessary elements may be supplied in kit form and the assembly and installation can readily be accomplished within a few minutes with minimum technical skill.

The principles of the invention as well as additional objects and features thereof will be fully apprehended from the following detailed description of an illustrative embodiment and from the drawing in which:

FIG. 1 is a simplified schematic circuit diagram of a coin telephone that includes a coin level detector arrangement in accordance with the invention;

FIG. 2 is a perspective view of a coin level detecting arrangement assembled in a coin receptacle;

FIG. 3 is a perspective view of the dual element sensor plate;

FIG. 4 is a side view of the sensor plate shown in FIG. 3;

FIG. 5 is a side view partially in cross section of the cover of the coin receptacle, the top of the coin receptacle vault and certain structural elements of the coin level detecting arrangement afiixed thereto;

FIG. 6 is a side view of a portion of the sensor assembly of FIG. 3 showing coins in the receptacle before contact is made with the signal plate; and

FIG. 7 is a side view of a portion of the sensor assembly of FIG. 3 showing coins in the receptacle after contact is made with the signal plate.

The simplified schematic telephone circuit diagram of FIG. 1 shows a conventional telephone speech network 10 connected across subscriber lines R and T with a line relay LR in the ring lead R. A path to ground from the network 10 is provided through the coin relay CR, the armature actuated switching member CR of the coin relay, the break contact BK, resistor R1 and the coin level detector 11. In accordance with the invention, the coin lever detector 11 completes the path to ground as described only when the level of coins collected in the coin receptacle exceeds some predetermined height. Irrespective of whether the coins in the coin receptacle exceed the predetermined height, however, the operation of the hopper trigger contact HTl, which is acuated conventionally by the deposit of any coin, shunts the coin level detector 11 and its associated resistor R1, thus, in effect, removing it from the circuit. The path to ground through the operated hopper trigger contact HT1 is detectable by the operator in the central office and is an indication that a coin or coins have been deposited in the hopper and that neither collection nor refund has been elfected.

When the coin relay CR is operated by a suitable pulse from the central oflice to efiect either coin collection or coin refund, the hopper trigger contact H'Il is reset in a well-known manner by associated apparatus, not shown; the path shunting the coin level detector 11 and resistor R1 is opened and the central otfice is once again able to determine whether or not the coin collection level in the coin receptacle has been exceeded by the presence or absence of a circuit to ground through the coin level detector 11.

Resistor R1 limits the flow of current to ground and effects a detectable voltage drop when the path to ground is completed through the coin level detector 11. Resistor R2 is conventional and its purpose is to limit the current flow to ground when the coin relay CR is shunted by the path through the coin relay armature switch CR and its make contact MK. In summary, from a circuit standpoint, a conventional coin telephone station circuit in order to utilize a coin level detecting arrangement in accordance with the invention, need only be modified by the addition of the coin level detector 11 and resistor R1 in the manner indicated in FIG. 1.

The key element of a coin level detector in accordance with the invention is a dual element sensor plate 301 shown in FIG. 3. The sensor includes an electrically conducting ground plate 302, an electrically conducting signal plate 303 and an insulating plate 304 sandwiched between. The lower edge of the signal plate 303 is bent outwardly to form a substantially horizontal ledge 303A. A similarly protruding ledge 304A is formed from the lower portion of the insulating plate 304. It should be noted in particular that the insulating ledge 304A extends slightly beyond the ledge 303A of the signal plate as shown clearly in FIGS. 6 and 7.

The signal plate 303 also includes a slotted tab 305 partially bent over an insulating tab 306 that limits the distance that the tab 305 may be depressed. The upper edge of the signal plate 303 is positioned by insulating clips 307307, and the entire sensor assembly is fixed rigidly together by fasteners 308308. The upper portion of the ground plate 302 terminates in a pair of integral clip members 309309.

As shown in FIG. 2 the clips 309309 permit the sensor assembly 301 to be afiixed simply yet securely to the rear wall of the coin receptacle 200. In FIG. 2 the cover 201 of the coin receptacle 200 is shown in the open position pivotally secured to the coin receptacle 200 by tabs 203-203 inserted in accommodating slots in the upper portion of the rear wall of the coin receptacle. When the cover 201 is closed, electrical contact is made between the cover and the clips 309-309. When the coin receptacle 200 is inserted in its protective enclosing vault in the conventional manner, the receptacle cover 201 is in electrically conducting contact with the vault 502, a portion of which is shown in FIG. 5. The vault 502 is a main structural part of the telephone and accordingly remains at ground potential.

OPERATION From the foregoing it is seen that in the absence of coins in the receptacle 200, the ground plate 302 is at ground potential and is completely insulated from the signal plate 303. As the level of coins in the receptacle 200 increases as additional coins are deposited, the top of the coin stack eventually contacts the insulating ledge 304A as shown in FIG. 6. Conducting contact with the signal plate 303 cannot occur, however, until the coins exceed the height of the ledge 303A at which point they form a conducting path between the ground plate 302 and the signal plate 303 as shown in FIG. 7. Once such contact is made, it is maintained inasmuch as intermittent or temporary contact between the signal plate and the coin stack that might otherwise be caused by edgebalanced or temporarily leaning coins is avoided in accordance with the invention by the relative positioning of the ledges 304A and 303A as shown in FIG. 6. The ledge 303A serves an additional function in that its horizontal surface ensures the aid of gravity in maintaining good electrical contact with the coins in physical contact therewith as shown in FIG. 7.

The final extension of ground potential to the terminal of resistor R1 by the coin level detector 11, as shown in FIG. 1, may be traced in FIG. 5. A conducting path is formed from the tab 305 of the signal plate 303 to a lug 202 which is in contact therewith when the cover 201 of coin receptacle 200 is closed. The lug 202 is mounted in an accommodating hole in cover 201 but is insulatedly separated therefrom. A conducting spring 505 is in electrically conducting contact with the top of the lug 202, and is insulated from the top of the vault by an insulating strip 501. A weld stud 504 attached to the conducting spring secures the spring 505- and strip 501 to the underside of the top of the coin telephone vault 502 and provides electrical continuity to a small nonconducting circuit board member 503 which is held in place on the upper surface of the vault 502 by the stud 504 and its associated nut 506. The resistor R1 is mounted on this terminal board and its lead is in electrical contact with the stud 504.

It is to be understood that the embodiment described herein is merely illustrative of the principles of the invention. Various modifications thereto may be made by persons skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. A coin operated telephone station comprising, in combination,

a receptacle for deposited coins,

a speech network connectable across a telephone line,

a source of reference potential,

first circuit means in said receptacle for completing a first electrical path from said reference potential through deposited coins to said network and thence to said telephone line whenever the coins in said receptacle exceed a preselected level, and

second circuit means including a hopper trigger contact responsive to the deposit of coins for completing a second electrical path from said reference potential to said network and thence to said telephone line,

said second circuit means shunting said first circuit means whenever said hopper trigger contact is in the operated condition,

thereby effectively avoiding any possible interference with the coin control functions of said station by said second circuit means.

2. A coin operated telephone station comprising, in

combination,

a speech network connectable across a telephone line,

a source of reference potential,

first circuit means responsive to the deposit of a preselected volume of coins for completing a conductive path from said source to said network and hence to said telephone line,

second circuit means including a hopper trigger contact responsive to the deposit of any coin for completing a conductive path to said network and hence to said telephone line,

said second circuit means shunting said first means whenever said hopper trigger contact is in the operated condition,

said hopper trigger contact remaining in the operated condition after the deposit of a coin or coins until the refund or collection of said last named coin or coins,

thereby avoiding any possible interference with said second circuit means by said first circuit means.

3. Apparatus in accordance with claim 2 including a coin receptacle,

said first circuit means comprising, in combination,

a first electrically conducting plate member afiixed fiat against the inside of one side of said receptacle and extending into the lower portion thereof,

an insulating plate covering the upper portion of said first plate,

first means connecting said first plate to said reference potential,

21 second electrically conducting plate afiixed to said insulating plate,

second means connecting said second plate to said network,

whereby deposited coins in said receptacle that reach the level of the lower portion of said second plate complete a conducting path between said first and second plates.

4. Apparatus in accordance with claim 3 wherein the lower edge of said insulating plate and the lower edge of said second pltae are bent outwardly to form a relatively narrow shelf,

the insulating plate portion of said shelf protruding beyond the second plate portion of said shelf,

whereby said insulating plate portion of said shelf avoids intermittent conducting paths that might otherwise be formed by temporarily edge-on or leaning coins,

and whereby said second plate portion of said shelf ensures gravity enhanced electrical contact between said shelf and coins resting thereon.

5. Apparatus in accordance with claim 3 wherein said second connecting means includes at least one resisttive element.

6. Apparatus in accordance with claim 3 wherein the upper portion of said first plate terminates in at least one clip member that secures said first plate to said side of said receptacle.

7. Apparatus for electrically detecting the level of coins in a coin collection receptacle comprising, in combination,

a source of reference potential,

a first electrically conductive plate exposed to conductive contact with coins in said receptacle below a preselected level,

a second electrically conductive plate exposed to conductive contact with coins in said receptacle above said level,

said plates normally being insulatedly separate,

whereby, an electrically detectable conductive path between said plates is established through deposited coins whenever the coins in said receptacle exceed said preselected level,

wherein the lower edge of said second plate forms a shelf portion extending out from the plane of said plates,

insulating means covering the underside of said shelf portion and extending beyond said shelf portion,

thereby precluding intermittent and unreliable conducting paths between said plates that might otherwise be formed by temporarily edge-balanced or leaning coins.

8. A coin level detecting arrangement for coin operated apparatus, comprising, in combination,

a box-like coin receptacle,

a first conductive plate member vertically disposed in said receptacle,

a second conductive plate member insulatedly separated from said first member and vertically disposed in said receptacle,

said first member being exposed to electrically conductive contact with coins in said receptacle up to a predetermined level,

said second member being exposed to electrically conductive contact with coins in said receptacle above said level,

means connecting one of said members to a reference potential,

whereby coins in said receptacle complete an electrically detectable conductive path to said reference potential whenever the level of coins in said receptacle exceeds said level, the lower edge of said second member being formed into a substantially horizontal ledge, at least a portion of the underside of said ledge being insulatedly protected from conductive contact with deposited coins,

thereby preventing completion of said conductive path by coins balanced edge-on or leaning against the underside of said ledge.

References Cited UNITED STATES PATENTS 1,571,962 2/ 1926 DeVilliers 340-421 3,091,663 5/1963 Stokes 179-63 3,112,366 11/1963 Gibbs 1796.4

KATHLEEN H. CLAFFY, Primary Examiner J. S, BLACK, Assistant Examiner

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1571962 *Oct 20, 1924Feb 9, 1926William H OvertonLiquid-fuel burner
US3091663 *Dec 20, 1960May 28, 1963Bell Telephone Labor IncCoin box telemetering arrangement
US3112366 *Sep 4, 1959Nov 26, 1963Gibbs William LSignalling devices for telephones
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4208549 *Jun 29, 1978Jun 17, 1980Bray Martin LCoin surveillance apparatus
Classifications
U.S. Classification379/147
International ClassificationH04M17/02, G07F9/06, H04M17/00
Cooperative ClassificationG07F9/06, H04M17/02
European ClassificationH04M17/02, G07F9/06