US 3776338 A
A system is provided in which the momentum of a moving credit indicator, such as a coin or token, is directed against a mechanically deformable converter, such as a piezoelectric crystal, to produce a signal pulse utilized in determining credit to be granted a vending machine customer. A separate compartment with an associated piezoelectric crystal is provided for each type of credit indicator deposited in the vending machine. The individual components of the system in each compartment are easily assembled and at least a number thereof are maintained in position without soldering or other fastening procedures until the compartments are assembled into a composite unit.
Description (OCR text may contain errors)
[ CREDIT PULSE GENERATING SYSTEM FOR VENDING MACHINES  Inventor: Kurt Theodore Johnson, Palatine,
 Assignee: The Seeburg Corporation oi Delaware, Chicago, Ill.
 Filed: Feb. 3, I972  Appl. No.: 223,147
OTHER PUBLICATIONS Castrodale; Piezoelectric Punch Checking Arrangement, IBM Technical Bulletin, Vol. 12, No. 9, 2-1970.
Sharp; Piezo-electric Crystal Keyboard", IBM Technical Disclosure Bulletin, Vol. 5, No. 10, 3-1963.
Primary Examiner-Robert B. Reeves Assistant Examiner-David A. Scherbel Attorney-.Ronald L. Engel et a1.
[57 4 ABSTRACT A system is provided in which the momentum of a moving credit indicator, such as a coin or token, is directed against a mechanically deformable converter, such as a piezoelectric crystal, to produce a signal pulse utilized in determining credit to be granted a vending machine customer. A separate compartment with an associated piezoelectric crystal is provided for each type of credit indicator deposited in the vending machine. The individual components of the system in each compartment are easily assembled and at least a number thereof are maintained in position without soldering or other fastening procedures until the compartments are assembled into a composite unit.
13 Claims, 20 Drawing Figures PATENTED DEC 4 I975 SHEET U 0F 4 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a system for producing an electrical signal in response to the motion of an inanimate object, and, more specifically, this invention relates to the use of a piezoelectric crystal to convert the motion of a coin or other credit indicator into an electrical signal without the necessity of any moving parts and hence replace conventional coin switches.
2. Description of the Prior Art It is customary in the vending machine field to validate deposited credit indicators, such as coins or tokens, and then direct these credit indicators to coin switches to register the appropriate credit. These coin switches normally include a pivoted lever or paddle which is struck by the falling coin. The paddle bears against a contact bearing switchblade at the end opposite that from the end of the paddle struck by the falling coin; Thus, striking of the paddle by the falling coin pivots the paddle and causes the movable contact on the switchblade to engage a contact on another switchblade and hence close an electrical circuit to produce the coin pulse.
These coin switches are extremely difficult to adjust accurately in order to give the proper pulses. For example, if the tension of the first switchblade is too great, the falling coin might rebound after the initial impact and thus cause more than one closure of the switch, which is generally known as coin or paddle bounce. On the other hand, if the tension is too small, the engagement of the contacts might be so 'forceable as to cause the contacts to strike and separate, thus causing contact bounce." These malfunctions may result in more credit being awarded than is called for by the credit indicator. Coin or paddle bounce and contact bounce might also result from improper adjustment of the tension of the second switchblade.
Due to the precision that is required in the adjustment of these switches, they are quite fragile and hence are easily damaged both during shipment and in operation. If the adjustments are inaccurate, either due to initial setting or subsequent impairment, the coin pulses may be too short or too long or otherwise unsuitable due to breaks or discontinuities.
Further, the fact that moving parts are utilized, there is always a considerable margin of error. For example, a paddle may wobble or stick. The margin of error is magnified and the switches become even more unreliable as dirt accumulates in the machine. Another disadvantage that results from usage is the socalled dirty contacts" that cause conducting problems, due to the accumulation of nonconducting materials on the contact surfaces.
SUMMARY OF THE INVENTION The present invention was developed in order to pro vide a credit pulse production arrangement in which there would be no moving parts. Briefly, this is accomplished by utilizing a mechanically deformable converter, such as a piezoelectric crystal or magnetostrictive device, against which a falling credit indicator such as a coin or token impinges. (For ease of reference, the
credit indicator will be hereafter referred to as a coin, but such reference is not to be viewed as a limitation on the use of the present invention, which may be utilized in connection with any type of moving object such as coins or tokens.) It should be noted that, strictly speaking, there is a movement of the converter upon deformation, but this motion is not of the type that creates the problems of prior art devices.
In the preferred embodiment disclosed herein, a piezoelectric crystal is utilized. The mechanical deformation of the crystal produces an electrical signal pulse in accordance with the well-known piezoelectric effect. It has been found that this pulse has a shape and magnitude that permits it to be directly utilized to drive logic circuits (after appropriate clipping). This eliminates the problems that resulted from the useof moving parts and the necessity of fine adjustments that are present in prior art coin switches, while at the same time permitting the removal of much filtering circuitry between the coin switch and the control circuitry of the vending machine.
These results are achieved by having a separate piezoelectric crystal for each denomination of coin (or token, etc.) that is deposited in the vending machine. Each coin is directed to a compartment in which a piezoelectric crystal representative of that denomination of coin is located. The directing means include a guide means which direct the coin to impinge upon a strip of flexible conducting material that acts as a striking area for the crystal. (Of course, the striking surface need not be a flexible strip but'could be a soldered wire, etc.). This flexible strip also holds the crystal snugly against a block of conducting material (the anvil), which is rigidly positioned on the other side thereof. The strip of flexible conducting material and the block of conducting material also serve as the conductors by which the electrical signal produced by the crystal is transmitted to appropriate circuitry in the vending machine.
Both the strip of flexible conducting material and the block of conducting material are mounted on a mounting wall. The block of conducting material is riveted to the mounting wall. A pair of mounting pins extend from the mounting wall on opposite sides of the piezoelectric crystal. Hence, mounting means for the crystal are provided on four sides by the mounting pins, the strip of flexible conducting material and the block of conducting material. The positioning of the mounting pins and the structure of the block of conducting material is Various attempts have been made to alleviate some of these difficulties, such as providing better and more easily operable adjusting arrangements. In other cases, some of the disadvantages have been overcome by electromagnetically inducing pulses in order to minimize the contact problems. However, even these improvements over the basic coin switches presently utilized have involved moving parts and at least some of the attendant difficulties.
such that a coin striking the strip of flexible conducting material and causing the piezoelectric crystal to produce a signal is directed away from the strip in an angular fashion, so that the coin does not rebound and again land on the flexible strip to produce a second pulse.
Supporting pins extend from the mounting wall to support another block of conducting material which is engaged by the other end of the strip of flexible conducting material. The flexible strip also bears against the end of a guide member and a positioning pin extending from the mounting wall that cause the strip to be distorted and bear against the crystal and the second block with a tension force. The force exerted by the strip of flexible conducting material on the piezoelectric crystal and the second block of conducting material causes these elements to be maintained in position without any additional securing or fastening devices, such as solder or mounting screws.
- The other surface of each mounting wall (except for the mounting wall at one end of the assembly) faces the mounting surface of a mounting wall in an adjacent compartment. Thus, the compartments are formed by placing two appropriate mounting walls in conjunction. After assembly of each of the compartments, end walls are located at each end of the stacked compartments and the whole assembly is permanently secured by two mounting bolts.
Therefore, it is the primary object of this invention to provide a device for producing credit pulses in a vending machine that does not utilize any moving parts.
Another object of this invention is to provide a system for producing credit pulses in a vending machine that does not require any switch adjustments.
It is a further object of this invention to provide a credit pulse producing system in a vending machine that generates credit pulses without the discontinuities exhibited by prior art devices.
Yet another object of this invention is to provide a credit pulse producing system for vending machines that permits the elimination of expensive filter circuitry needed with prior art devices.
Still a further object of this invention is to provide a coin-pulse producing system that may be easily assembled and which may be maintained with'a minimum of fastening devices.
Still another object of this invention is to provide a coin pulse producing system in which some of the components of the individual coin compartments are maintained in place during assembly without the necessity of any extra fastening devices.
These and other objects, advantages, and features of this invention will hereinafter appear, and for purposes of illustration, but not of limitation, exemplary embodiments of the subject invention are shown in the appended drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view of the credit pulse generating system of the present invention shown connected to the coin chute of a vending machine.
FIG. 2 is a right side view of the device illustrated in FIG. 1.
FIG. 3 is a top plan view of the credit pulse generating system illustrated in FIG. I.
FIG. 4 is a partially exploded view illustrating the components of a single coin compartment in the credit I FIG. 9 is a plan view of'the mounting surface of a mounting wall for another compartment of the credit pulse generating system of the present invention.
FIG. 10 is a plan view of the other surface of the mounting wall illustrated in FIG. 9.
FIG. 11 is a plan view of the mounting surface of the mounting wall for still another coin compartment of the credit pulse generating system of the present invention.
FIG. 12 is a plan view of the other surface of the mounting wall illustrated in FIG. 11.
FIG. 13 is a plan view of the mounting surface of the mounting wall for yet another coin compartment in the credit pulse generating system of the present invention.
FIG. 14 is a plan view of the opposite surface of the mounting wall shown in FIG. 13.
FIG. 15 is a schematic illustration of a typical coin pulse produced by prior art coin switches.
FIG. 16 is a schematic illustration of a pulse produced by the credit pulse generating system of the present invention.
FIG. 17 is an enlarged view of the converter portion of the credit pulse generating system of the present invention.
FIG. 18 is another embodiment of the present invention.
FIG. 19 is another embodiment of the present invention.
FIG. 20 is another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED. EMBODIMENT herein utilizes coins, reference to the credit indicators deposited in a vending machine will be limited to coins for purposes of this description of the preferred embodiment.
The credit pulse generating system encapsulated unit 20 is bounded by an end wall 24 (FIGS. 5 and 6) and mounted on a projecting plate 26 from coin chute 22. Individual coin compartments are formed by mounting walls 28, 30, 32 and 34, in conjunction with end wall 24, in this particular embodiment. It should be recognized, of course, that the use of four coin compartments is merely illustrative of this particular embodiment and that as many coin or credit indicator compartments as required for a particular situation may be employed. Y
The individual mounting walls 28, 30, 32 and 34 are illustrated in FIGS. 7 & 8, 9 & 10, 11 & l2, and 1 3 & 14, respectively. Each 'of the mounting walls has thereon the components shown in the exploded view of FIG. 4. A pair of mounting pins 36 and 38 extend from the mounting wall to provide a space therebetween for a piezoelectric crystal 40, which is the mechanically deformable converter utilized in this preferred embodiment. Of course, another type of mechanically deformable converter, such as a magnetostrictive device, could be utilized also. Pins 36 and 38 are placed such that a line through the centers thereof would be at an angle to the horizontal. Piezoelectric crystal 40 may be placed to produce either positive-going or negativegoing signals. One surface may be coated with a gold conductor while the opposite surface is coated with a silver conductor in order to readily determine the appropriate positioning in order to obtain the desired polarity. 1
The piezoelectric crystal 40 rests on a block of conducting material 42. Block 42 may be formed of any suitable conducting material, such as brass. A sloped surface 44 is provided on block 42 at an angle to match the angle of pins 36 and 38. At the other end of block 42 there is located a terminal 46, which extends beyond casing 20.
A strip of flexible conducting material 48 is positioned above the piezoelectric crystal 40 and pins 36 and 38. The non-horizontal relationships of pins 36 and 38, and the corresponding slope of portion 44 ofblock 42, is provided in order to have the top surface of crystal 40 parallel to strip 48. Strip 48 is at an angle to the horizontal to insure that after a coin strikes the piezoelectric crystal it is deflected away from the crystal so as to prevent any coin bounce, or repetitive actuations.
Flexible strip 48 may be any type of spring metal, such as phosphor bronze. The strip of flexible material 48 bears against the crystal 40 through a dimple 49 (FIG. 17) and forces it against sloped portion 44 of block 42, which provides a rigid support or anvil. Flexible strip 48 provides a striking surface against which the coin impinges to compress the crystal 40, and the dimple 49 concentrates the pressure at a given point. The coin is directed against flexible strip 48 by a guide member 50, an end 52 of which serves to support and position the strip 48. End 52 of guide member 50 and a positioning pin 54, which extends from the mounting wall, position and distort strip 48. Strip 48 also has an extended end portion 56 transverse to the length of strip 48. End portion 56 engages a groove 58 in a second block of conducting material 60. The block 60 has an extending terminal 62 which also protrudes beyond casing 20. Block 60 is mounted on supporting pins 64 and 66, which extend from the mounting wall. Block 42 is mounted on the mounting wall by rivets 68 and 70.
When the components are being assembled on the mounting wall, block 42 is riveted in place and .block is placed on its supporting pins 64 and 66. Flexible strip 48 is then forced into position so that it engages blocks 60, positioning pin 54, end 52 of guide member 50 andpiezoelectric crystal 40. Piezoelectric crystal 40 may be inserted between mounting pins 36 and 38 either before or after insertion of the flexible strip 48, although it is normally preferable to do ,it after the strip is in position to minimize the possibility of damage to the crystal. As it is necessary to deform strip 48 in order to fit it in the allowed place, it is tensed and serves to retain all the components in place during assembly of the unit. After all the components have been mounted on each of the mounting walls, the individual mounting walls are joined together with end wall 24. Spacers 72, 74, 76 and 78 formed on mounting walls 28, 30, 32 and 34, respectively, position the tops of the mounting walls apart from each other in order to form individual coin compartments 73, 75, 77 and 79. A spacer 80 separates plate 26 from mounting wall 34. In asimilar fashion, the bottom portions of the mounting walls and end wall 24 are separated by spacers 82, 84, 86, 88, with spacer separating mounting wall 34 from plate 26.
Each of the spacers has a projecting portion that mates with a corresponding bore on the opposing wall to maintain all the walls as a composite unit until the structure is permanently bound together by bolts 92 and 94, with their respective nuts 96 and 98. These bolts pass through an opening provided in the spacers 72, 74, 76, 78, 80, 82, 84, 86, 88 and 90 and their corresponding projections.
Referring now to FIGS. 5-14, the structure of end wall 24 and the individual mounting walls may be seen. FIG. 5 illustrates the outer side of end wall 24 and the openings 100 and 102 through which bolts 92 and 94 pass,,respectively. FIG. 6 depicts the other side of end wall 24 which, along with the surface of mounting wall 28 illustrated in FIG. 7, forms a nickel coin compartment. On this side of end wall 24 bores 104 and 106 are formed about openings 100 and 102, respectively. These bores mate with projections 108 and 110, respectively, on mounting wall 28. As illustrated in FIG. 7, projections 108 and 110 extend from sleeves 82 and 72, respectively. An upper end portion 112 of end wall 24 is flared outwardly, so that with a corresponding flared end portion 114 on mounting wall 28 a coin receiving slot is formed.
A tab 116 is formed on end wall 24. Correspnding tabs 118, 120, 122 and 124 are formed on mounting walls 28, 30, 32 and 34, respectively. These tabs are utilized as an indexing device, so that when the individual walls are placed together it may be seen at a glance whether they have been put in the proper relative positions. This is achieved by placing each of the tabs at a slightly different position, so, as may be seen in FIG. 1, from a side view the tabs would appear as a solid line. If there is a break in this line, it is immediately obvious that one of the mounting walls (or the end wall) has not been placed in the proper position.
In FIG. 7 it may be seen that mounting surface of mounting wall 28 has been provided with an additional guide member 126. Guide member 126 serves, along with guide member 50, to direct the coin against the flexible striking surface 48. Guide member 126 has a length such that a coin rebounding from the striking surface 48 will not strike the guide member 126, which would cause the coin to rebound against the striking surface and the piezoelectric crystal, but will permit the coin to pass on to, an appropriate coin box.
The other side of mounting wall 28 is illustrated in FIG. 8, which, along with the mounting surface of mounting wall 30 illustrated in FIG. 9, forms the quarter coin compartment of this embodiment of the invention. A series of three ridges 128, 130 and 132 extend from this side of mounting wall 28. These ridges determine the width of the compartment between the ends of these ridges and mounting wall 30 through which the quarters pass. The upper portion 134 of mounting wall 28 is flared back toward the nickel compartment, in order to form a coin receiving slot with a flared upper portion 136 of mounting wall 30. Bores 138 and 140 mate with projections 142 and 144, respectively, on mounting wall 30 to position mounting walls 28 and 30 with respect to each other. A guide member 146, similar to guide member 126 but adapted to the larger size ot'the quarter coin, is formed on mounting wall 30.
The other side of mounting-wall 30 (FIG. 10) cooperates with the mounting surface of mounting wall 32 to form the dime coin compartment. Ridges 148 and 150 define the size of the dime compartment. Upper portions 152 and 154 of ridges 148 and 150, respectively,
are flared toward the quarter compartment to form a coin receiving slot for the dimes in conjunction with a similarly flared portion 156 at the top of mounting wall 32. Bores 158 and 160 mate with projections 162 and 164, respectively, on mounting wall 32 to position and maintain mounting walls 30 and 32 with respect to each other.
Mounting surfaces of mounting walls 32 and 34, as illustrated in FIGS. 11 and 13, are essentially the same as the mounting surfaces of the mounting walls illustrated in FIGS. 7 and 9. Mounting wall 32 has a guide member 166 and mounting wall 34 has a guide member 168 which are adapted to the size of the respective dime and half dollar coins with which these mounting walls are associated. The other side 'of mounting wall 32 has three extended ridges 170, 172 and 174 which have respective flared top portions 176, 178 and 180 which, along with flared portion 182 on mounting wall 34, form a coin receiving slot for the half dollars.
FIGS. and 16 illustrate comparative pulses produced by a conventional coin switch and the pulse generating system of the present invention. In the example of a coin switch pulse illustrated in FIG. 15, a first break 184 occurs as the result of contact bounce produced when the contacts are caused to engage a coin striking the actuating paddle. Breaks 186, 188, 1 90, 192 and 194 occur as a result of dirty contacts or insufficient contact force (which could result from an improper adjustment of the switchblades). Break 196 occurs from paddle bounce resulting from too great a tension in one of the switchblades. It is apparent that a pulse of this nature would have to be carefully filtered in order to preclude the unwarrented granting of credit to a customer and to distinguish one coin pulse from another. Of course, not all coin switch pulses are this imperfect, but even one break creates the problem.
On the other hand, the pulse produced by the system of th present invention, as illustrated in FIG. 16, is a single clean pulse that may be clipped at any desired level, such as at the point shown by line 200, to produce a single pulse that requires no filtering and which may be fed directly to controlling logic circuitry. Obviously, the prior art disadvantages have been obviated to a considerable degree.
Although there are no moving parts, dirt accumulation in the system could still create some problems by creating low-leakage resistance paths. With the-unit produced pursuant to the present invention it is not neessary, however, to dismantle the assembly for cleaning. The system may be easily cleaned by merly sloshing the entire unit in a proper detergent solution and shaking out any excess detergent.
It should be recognized that forces other than the compression force used in the preferred embodiment may be utilized to deform the crystal and produce electrical signal. For example, a bending force or a torsion force could be utilized to deform the crystal.
FIG. 18 illustrates an arrangement in which a bending force is used instead of a compression force. In this embodiment, a falling coin 202 strikes a paddle 204. Rotation of paddle 204 under the force of the coin causes actuating rod 206 to follow the motion of end 208 of paddle 204 as a result of the force of spring 210.
to assume the dotted line position shown in FIG.'18. After the coin 202 passes the end of paddle 204, return spring 212 returns the paddle 204, actuating rod 206 and crystal actuator 214 to the solid line positions shown in FIG. 18. The motion of crystal actuator 214 causes the crystal unit 216 to produce an output signal by bending and hence deforming crystal 218. The signal is picked up by conducting plates 220 and 222 and conveyed to the vending machine system by leads 224 and 226.
This alternative embodiment still has the problems inherent in a moving paddle, but is does eliminate the need for accurate adjustment of switchblades and an external power source.
In FIG. 19 another embodiment is shown in which a coin 228 strikes an impact block 230. The impact block moves a rod 232 to cause a plunger 234 to impact on crystal 236. The resultant deformation of crystal 236 produces an electrical signal on leads 238 and 240.
The embodiment shown in FIG. 20 is a generalized version of the preferred embodiment described herein.
- A coin 242 hits a striking pad 244 to distort crystal 246 Spring 210 is relatively weak in comparison to the return spring 212. As the coin 202 rotates the pedal 204, the actuating rod 206 causes the crystal actuating 214 and produce an electrical signal on leads 248 and 250. Both the FIG. 19 and FIG. 20 embodiments, of course, utilize a compression force. I
It should be understood that various modifications, changes, and variations may be made in't'he arrangements, operations, and details of construction of the elements disclosed herein without departing from the spirit and scope of this invention.
l. A credit pulse generating system-for a vending machine comprising:
a plurality of mechanically deformable converters,
each of said deformable converters representing a particular credit indicator;
mounting means supporting each of said deformable converters in a given position, said mounting means comprising: 1
a mounting wall for each type of credit indicator;
a pair of restraining devices on each of said mounting walls, the deformable converter for that credit indicator located therebetween;
a plurality of blocks of conducting material, each of said blocks extending across an associated pair of said restraining devices on one side thereof; and
a plurality of strips of flexible conducting material, each of said strips extending across an associated pair of said restraining devices on the other side thereof to retain the corresponding deformable converter between said restraining devices and against the associated block of conducting material and to provide said striking surface for deposited credit indicators;
directing means causing each credit indicator deposited in the vending machine to stress the deformable converter representing that particular credit indicator, said stress of each of said deformable converters being a compressive force occasioned by the associated credit indicator impinging upon a striking surface to compress that deformable con- .verter; and electrical means for detecting and transmitting signals generated by distortion of said mechanically deformable converters upon stress thereof from transfer of kinetic energy from the associated credit indicators thereto.
2. A system as claimed in claim 1 wherein said mechanically deformable converters are piezoelectric crystals.
3. A system as claimed in claim 1 wherein said restraining devices are mounting pins.
4. A system as claimed in claim 1 wherein each of said strips of flexible conducting material is positioned at an angle to the line of motion of said credit indicators in order to prevent said credit indicators from striking said deformable converters more than once.
5. A system as claimed in claim 1 and further comprising a projection formed on each .of said strips of flexible conducting material to engage the corresponding deformable converter.
6. A system as claimed in claim 1 wherein said electrical means comprise said blocks of conducting material and said strips of flexible conducting material.
7. A system as claimed in claim 1 and furthercomprising:
a positioning projection for each of said strips of flexible conducting material; and
a second plurality of blocks of conducting material,
each of said blocks having a groove formed therein. 8. A system as claimed in claim 7 wherein: each of said strips of flexible conducting material has a transverse projection formed on one end thereof; and each of said directing means comprises a guide member having one end thereof located in proximity to said positioning projection,
whereby forcing said strip of flexible conducting material between said positioningprojection and said end of said guide member distorts said strip, causing said transverse projection thereof to engage said groove of an associated one of said second plurality of blocks of conducting material and causing the other end thereof to forcibly engage the associated deformable converter.
9. A system as claimed in claim 8 and further comprising a terminal located on each block of conducting material, whereby the electrical signal produced by a credit indicator striking a deformable converter appears between terminals on an associated one of said plurality of blocks of conducting material and on an associated one of said second pluralityof blocks of conducting material.
10 10. A credit pulse generating system for a vending machine comprising:
an end wall and a plurality of mounting walls, said walls being placed in proximity to form a plurality of compartments therebetween, each type of credit indicator deposited in the vending machine having a separate compartment representative thereof;
each of said compartments comprising:
a pair of mounting members on said mounting wall;
a first block of conducting material rigidly mounted on said mounting'wall, said first block being located beneath and extending across said pair of mounting members;
. a mechanically deformable converter positioned between said pair of mounting members and on top of said first block of conducting material;
a strip of yieldable conducting material having a portion at one end extending transversely to the length of said strip;
a second block of conducting material mounted on supporting pins protruding from said mounting wall and having a groove therein adapted to receive said portion of said flexible strip;
directing means including a pair of guide members for directing a deposited credit indicator toward said deformable converter;
a positioning projection, the end of one of said guide members being located such that when said flexible strip is forced between said positioning projection and said one guide member said strip is distorted with said portion thereof forced into said groove in said second block and the other end thereof forced against said deformable converter; and
a terminal connected to each of said first block and said second block to detect an electrical signal produced by a credit indicator striking said flexible strip immediately above said deformable converter.
11. A system as claimed in claim 11 and further com-.
formable converter is a piezoelectric crystal.