US3629563A - Signal convertor - Google Patents

Abstract

A device for converting the value in a mechanical register, into electrical output signals. Tracks between each tooth of each gear of the register contain the value of the teeth in binary form. In setting the gears, the tracks are aligned to form a continuous track passing through all the gears of the register. A sensing finger which is connected to a photocell runs through this continuous track to convert the setting in the register gears to electrical output signals.

Description

United States Patent [72] Inventors Costa R. Englund;

Mats E. Mattsson; Clues-Goran Llndelow, all 01 Stockholm, Sweden [21 l Appl. No. 740,175 [22] Filed June 26, 1968 {45] Patented Dec. 21,1971 [73] Assignee Svenllta Dntaregllter AB SOIIII, Sweden [54] SIGNAL CONVERTOR 13 Claims, 6 Drawing Figs.

[52] U.S. C1 235/154, 235/60.4, 340/357 [51] Int. Cl G08c 9/06 [50] Field of Search 340/357, 358, 347; 235/604, 60.48, 154

[56] References Cited UNITED STATES PATENTS 2,247,942 7/1941 De Koevend 340/357 2,758,297 Q1956 genes et al. 340/357 X 40 e lo 6 2,895,121 7/1959 Bliss 340/357 X 2,993,200 7/1961 Walker et al. 340/347 3,230,454 1/1966 Van Burkleo 340/357 X 3,416,134 12/1968 Gertleretal.... 340/357 X 2,656,106 10/1953 Stabler 340/347 2,866,183 12/1958 Awot etal. 340/347 3,041,598 6/1962 Betts 340/347 Primary Examiner-Maynard R. Wilbur Assistant ExaminerCharles D. Miller Attorneys-Norman Friedman, Stephen E. Feldman, Arthur T. Groeninger, Morris 1. Pollack and Philip Furgang PATENTEU DECZI |97l 3.6291563 sum 1 UF 6 GOSTA R. MATS E. CLAES-GORA BY ATTORNEY mama] UECZI um 3.629.583

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SHEET 6 [IF 6 Fig 6 INVENTORS GOSTA R. ENGLUND MATS E. MATTSSON CLAES-GORAN LINDELOW WFZ ATTORNEY SIGNAL couvssros BACKGROUND OF THE INVENTION Data processing has developed rapidly in the last few years, and is in use today for a wide variety of purposes. One area where this use is especially important is in small business. I-Iere modern electronic data processing equipment is used for accounting, bookkeeping, and other purposes.

In this connection, a frequent problem occurs, especially in office machines, in converting digital information in a mechanical register such as the registers used in cash registers to electrical output signals for use in data processing equipment.

In one prior art device, digital information was transferred within a machine from one gear register to another. The information in the latter register was indicated by projections on each gear (other than the gear teeth). Sensing was then done by an arm which moved from one gear to the next over the projections. The sensing arm contained normally open electrical contacts which were pressed together and closed to produce electrical signals as the arm rode over a projection. Since these contacts were constantly opened and closed throughout their travel along the register gears, the slightest bit of foreign matter between them would cause improper operation and a resulting erroneous signal. Further, double pulses also causing erroneous signals would be produced occasionally due to rebounding of the contacts caused by their constant opening and closing.

The device also lacked a way to determine when the sensing arm passed from one order to the next of the register and therefore there was no effective way to determine the total value in the register gears. For example, if there was a four in the first gear and a one in the second gear, or a value of 14, this could not be distinguished from a two in the first gear and a three in the second gear or a value of 32, since five pulses would be indicated in both cases because the sensing arm would pass over five projections on the gears.

Applicants invention, on the other hand, eliminates these disadvantages by providing a photoelectrically responsive sensing means which senses a continuous track in the register gears and thereby does not have to be constantly opened and closed and also by providing a photoelectrically responsive device which indicates when the sensing means has passed from one gear to the next.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the device of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along line A-A in FIG. I with parts broken away.

FIG. 3 is an enlarged cross-sectional view of the sensing means taken along line BB in FIG. 2.

FIG. 4 is a cross-sectional view taken along line C-C in FIG. 1 and showing a cross-sectional view of the sensing means taken along lines D-D in FIG. 3.

FIG. 5 is an enlarged view of the device shown in FIG. 1 with parts broken away.

FIG. 6 is an alternative embodiment of the device of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT This construction includes a plate 1 which, as shown in FIG. I, is fastened on the back of a cash register by suitable screws 2. Supported on and secured to the plate by screws 3a is a mechanical register including gears 4 positioned on shaft 3. These gears which are hereinafter referred to as code rolls are held in their lateral positions by spaced collars 3b located at either end of the shaft 3.

As will be seen from FIG. 2, the rolls are set by gears 5 through intermediate gears 6 mounted on shaft 60. In order for gears 6 to mesh with the code rolls, the gears pass through openings la in plate 1 and are each aligned with a respective gear 5 in each order of the register. Each code roll will thereby receive information from its corresponding register gear.

The code rolls, as shown in FIG. 2, each have 10 gear teeth 7 separated by 10 tooth spaces 8. In each of these tooth spaces, an engraved track or groove 9 is positioned (FIG. 5). It is noted that for the sake of simplicity in FIGS. 2 and 4 only one of the spaces 9 between the teeth of the code rolls is shown. However, all of the spaces 9 are provided in the actual construction. The tracks which are shaped in accordance with a predetermined code, which is preferably a binary one, each represent one of the digits 0-9, as will be described hereinafter in more detail. The preferred binary code has four bits which are used to represent the digits 0-9 and a fifth bit which is used for parity control. The binary code used is shown in the following table.

Every tooth space in each code roll is divided into five bit positions, 400, b, c, d, and e, as shown in FIG. 5. In each bit position, the track can have an upper position 41a which indicates a binary zero or a lower position 41b which indicates a binary one.

The P in the above-mentioned binary code stands for the parity position which is the e-bit position and is used for checking the correctness of the signal. The parity adds the binary one when the number of binary ones is odd and adds the binary zero when the number of binary ones is even so that the total binary ones will always be even.

Also fastened to plate 1 and positioned parallel to shaft 3 is a shaft 10. The shaft, which is fastened to the plate 1 by screws, has movably mounted thereon a carriage including a sensing converter means or probe 12. The carriage includes two projections 13a and 13b which fit within the spaces 8 between the teeth 7 of code rolls 4. Sensing converter 12 is mounted on one of each projections, 13b.

Each code roll can be rotatably set to any one of the 10 positions representing the digits 0-9. When all the code rolls are set to a digit position (including 0) their teeth 7 will be aligned so that the gaps 8 between their teeth and tracks 9 therein are aligned. In this position, tracks 9 form continuous channels running through all the registers gears; sensing means 12 can then be continuously moved in these channels from one end of the register to the other without being I removed therefrom. It will, of course, be appreciated that in control pin, which is connected to a wing-type shutter 14, moves in the track to read out the amount in the code rolls and convert it into electrical pulses, as will be described in greater detail hereinafter.

The sensing converter 12 is a photoelectrically operated device and includes a photocell 17 positioned for producing information signals and another photocell 18 for producing synchronization signals, as will be hereinafter described. These photocells are mounted and connected to circuit board 19 which provides the electrical circuitry necessary for operation.

Lamps 20 and 21 are also mounted and connected to a suitable circuit board 22 in the same manner as the photocells and are positioned to receive light therefrom.

Between the lamps and the photocells, a rotatable drum 23 is positioned. The drum has pairs of slots in its surface (24, 25 and 24', 25') which are located so that light from lamp 20 will pass through slots 24 or 24 to be received by photocell 17 and light from lamp 2! will pass through slots 25 or 25' to be received by photocell 18.

It will be appreciated that there are a total of eight slots in the drum, two slots 24 which are 180 apart and aligned with each other, and two other slots 24 which are also 180 apart and aligned with each other. Slots 24 are 90 apart from the slots 24 so that a straight lines through slots 24 would be perpendicular to a straight line through slots 24. The same relationship also exists between slots 25 and 25'.

The drum is rotated because a gear 26 thereon meshes with a rack 27! which is positioned parallel to shafts 3 to and secured to plate 1 by screws 27a.

Between the drum and the photocells, a shield 28 is positioned to prevent unwanted light from falling on the photocells. The shield has two slots, 28a and 28b, therein (FIG. 4) which correspond in size respectively to slots 24, 24', and 25, 25' in drum 23. Slot 28a is aligned with lamps 20 and photocell 17 and slot 28 is aligned with lamp 21 and photocell 18. The alignment of the slots allows light to pass through the slots when drum 23 is in certain angular positions. Opaque shelf 16 is also provided to prevent the unwanted escape of light.

A wing-type shutter 14 is rotatably mounted by pin 29 on casing 16. In operation it rotates to cover opening 24 or 24 and prevent light from lamp 20 from falling on photocell 17. It will be noted that slots 24, 24' are wider in the direction of rotations of the drum 23 than slots 25, 25'. The difference in width is provided so that shutter 14 will have sufficient time to be removed from the path of light through slot 24 or 24' before the light from lamp 21 passes through slots 25 or 25. Because of this construction, tracks 9 and sensing pin do not have to be machined to as high as a degree of precision as if the slots were the same size.

As aforementioned, tracks 9 and e code rolls have five bit positions 40a-e in which information can be placed. In order to determine when one of these positions is being read by photocell l7 synchronizing photocell I8 is provided. This photocell which works in conjunction with lamp 21 and slots 25 or 25 in drum 23 produces a signal in every bit position because no shutter is associated therewith. It will produce five pulses for each code roll to positively indicate when the sensing means passes from one code roll to the next.

If there was no synchronizing signal, there would be no way of determining positively when the sensing device moved from one order to the next of the code rolls, and an incorrect number would thereby be indicated. For example, if five binary one pulses were produced, there would be no way of determining whether these all came from the lowest order code roll which would indicate a value of five or three came from the lowest order code roll and two came from the next order code roll which would indicate a value of 23. This problem, as aforementioned, is avoided with synchronizing signals.

It will be appreciated that applicants method of producing synchronizing signals is far easier than in the prior art. In the prior art, synchronizing signals were generated separately by a clock generator, the frequency of which was synchronized with the rate at which the sensing carriage moved along the code rolls. Also, occasionally, in the prior art, synchronizing signals were generated by code indications in the sensing track, but in this case, since both information and synchronizing signals had to be placed on the code rolls, the amount of information that could be placed in the information signals was substantially decreased. In our device, on the other hand, since a separate set of synchronization signals in the tracks is not required, the amount of information that can be provided in the tracks is significantly increased. Also, since the synchronizing signals are produced by the sensing carriage movement and not by its velocity, synchronization is far easier to control.

Now referring back to the operation of carriage 11, the carriage including converter 12 is driven by means of a cord 23 which is connected to the carriage. The core runs in the outer track 32 of a pulley 30, mounted on shaft 31, as shown in FIG. 1. The cord is attached to the pulley by its ends being connected to springs 35 which are connected to pulley spokes 33. Intermediate pulley 35 which are rotatably mounted on pins 37, are also provided to guide the cord and thereby guide the carriage along its path.

The operation of the present mechanism will now be described. Assuming the number 247 is in a register and it is desired to convert this number to electrical output signals, the three code rolls 4a, b, and c as shown in FIG. 5 are respectively set by the register gears to 2, 4 and 7; code roll 4a is set to position 2, code roll 4b is set to 4, and code roll 4cis set to 7. These positions are shown in FIG. 5, by track 9 in the center of the code rolls. The track below the center track represents the numbers 1, 3 and 6 and the track above the center represents the numbers 3, 5 and 8. It is noted that for simplicity the sensing means in FIG. 5 is shown sensing the lowest tracks on the code roll, whereas we have mentioned that the center track is the one we were interested in sensing. In operation, the track being sensed would be in the lowest position, but simply for purposes of illustrating the exact configuration of the sensed track, we have shown it in the center position. It will of course be appreciated that during normal operation, it would be in the lower position.

The motor then rotates pulley 30 to drive cord 34 in a clockwise direction to cause carriage 11 to move to the right in FIG. 5. Since sensing pin 15 is connected to the carriage, it will move with the carriage along the code roll to sense the amount of each track 9 of each roll. As the carriage is moved, drum 23 will be rotated since gear 26 connected to the carriage meshes with rack 27. Each time the drum is rotated, light from lamps 21 will pass through either slot 25 or slot 25'. Gear 26 and rack 27 are constructed so that light will pass through the drum in every bit position (a, b, c, d, and e) of the code rolls. Light from lamp 20 will also attempt to reach photocell 17 in every bit position, but will only succeed in reaching the photocell when a binary one is sensed (the lower track position 41b), since in that position shutter 14 will not block the slot in drum 23. Therefore, in accordance with the example, as sensing pin 15 follows track 9, light will be received by photocell 7 in bit positions 2 and 5 of the code roll 40, positions 3 and 5 of code roll 4b, and positions 2, 3 and 5 of code roll 40. As these signals are received by the photocell, it will generate electrical impulses to indicate the set number 247.

These electrical impulses can then be stored on magnetic tape or other suitable mechanism for subsequent processing.

An alternative form of the invention is as shown in FIG. 6. A single source of light 39 is mounted on plate 1 adjacent one end of rack 27 and photocell unit 40 with photocells l7 and 18 mounted thereon is mounted adjacent the other end of the rack. In this embodiment, carriage 11 includes only drum 23 since the light source 39 and the photocells are connected to the fixed plate 1.

In still another embodiment, a single source of light 39 is mounted as shown in FIG. 6, but the two photocells l7 and 18 are provided on carrier 11 as shown in FIG. I.

It will be appreciated that cover 16, which was previously mentioned as being opaque will be constructed of transparent material when photocells l7 and 18 are mounted as in FIG. 6 so that light can pass therethrough.

Specific embodiments of our invention have been illustrated but the invention is not limited thereto since many modifications may be made by one skilled in the art and the appended claims are intended to cover all such modifications as fall in the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. A mechanical electrical signal converter comprising:

a movable member having a reference line which member is settable to a value position representing a mechanical signal,

a sensing means for converting the mechanical signal to an electrical signal,

a plurality of coded means indicative of the value to which said movable member can be set, which means are disposed on said member, each of which extends continuously in the path of said sensing means from one side of said member to the other side and is always at a uniform distance from said reference line, so that said sensing 'means in sensing said coded means to convert the mechanical signal to an electrical signal will remain at a uniform distance from said reference line,

said coded means comprises means having a plurality of continuous coded grooves in said member,

said sensing means is operatively related to a photoresponsive means to thereby convert the setting of said settable member to an electrical output signal,

a light source,

said sensing means includes a movable'shutter which is movable between a first position where light from said light source is received by said photoresponsive means to cause a signal to be generated and to a second position where light from said light source is prevented from being received by said photoresponsive means to thereby prevent an output signal from being generated,

means is provided for transferring mechanical information into said settable member, and

said means having coded grooves is operatively connected to said switching means to switch said shutter between two positions, one position wherein said shutter is positioned to permit the admission of light to said photoresponsive means, and a second position wherein said shutter is positioned to prevent the admission of light to said photoresponsive means.

The signal converter of claim 1 including:

plurality of said settable member which are positioned about a shaft, each one related to an order of a register means, and

wherein said sensing means is movable in a path parallel to said shaft.

3. The signal converter of claim 2 wherein:

said light source and said photoresponsive device are fixed with respect to said movable sensing member.

4. The signal converter of claim 2 wherein:

said photoresponsive means is included in said sensing means and said light source is fixed with respect to said movable sensing means.

5. The converter of claim 2 wherein:

said photoresponsive means comprises two photocells, one of which is responsive to the actuation of said shutter, and the other which is actuated independently of said shutter.

6. The signal converter of claim 5 wherein:

a rotatable drum is positioned between said light source and said photocells in a plane perpendicular to the light path to each photocell and having apertures therein to permit light periodically to pass between said light source and said photocells.

7. The signal converter of claim 6 wherein:

means is provided to rotate said drum so that one of said apertures will Fermitli ht to pass from said light source to said photocel as sar sensing means passes through a said apertures in said rotatable drum include two sets of apertures which are perpendicularly disposed with respect to each other.

9. The signal converter of claim 8 wherein:

one set of said apertures in said drum are related to said shutter means and are wider than the other set of apertures in said drum.

10. The signal converter of claim 9, including:

a rack parallel to the axis of said settable means, and

a gear which is connected to said drum, and meshes with said rack so that said drum is rotated when said sensing means to moved parallel to said settable means.

11. The signal converter of claim 10 wherein:

said settable means comprises a plurality of rotatable gears,

said grooves are located between the teeth of said gears,

and wherein said reference line passes thru the center of each of said gears.

12. The signal converter of claim 1 1, including:

10 teeth on each gear with spaces therebetween and 10 grooves, one in each space, which grooves represent the digits 0-9.

13. The signal converter of claim 12 wherein:

the grooves are coded according to a binary code comprising five bits.

Claims (13)

1. A mechanical electrical signal converter comprising: a movable member having a reference line which member is settable to a value position representing a mechanical signal, a sensing means for converting the mechanical signal to an electrical signal, a plurality of coded means indicative of the value to which said movable member can be set, which means are disposed on said member, each of which extends continuously in the path of said sensing means from one side of said member to the other side and is always at a uniform distance from said reference line, so that said sensing means in sensing said coded means to convert the mechanical signal to an electrical signal will remain at a uniform distance from said reference line, said coded means comprises means having a plurality of continuous coded grooves in said member, said sensing means is operatively related to a photoresponsive means to thereby convert the setting of said settable member to an electrical output signal, a light source, said sensing means includes a movable shutter which is movable between a first position where light from said light source is received by said photoresponsive means to cause a signal to be generated and to a second position where light from said light source is prevented from being received by said photoresponsive means to thereby prevent an output signal from being generated, means is provided for transferring mechanical information into said settable member, and said means having coded grooves is operatively connected to said switching means to switch said shutter between two positions, one position wherein said shutter is positioned to permit the admission of light to said photoresponsive means, and a second position wherein said shutter is positioned to prevent the admission of light to said photoresponsive means.

2. The signal converter of claim 1 including: a plurality of said settable member which are positioned about a shaft, each one related to an order of a register means, and wherein said sensing means is movable in a path parallel to said shaft.

3. The signal converter of claim 2 wherein: said light source and said photoresponsive device are fixed with respect to said movable sensing member.

4. The signal converter of claim 2 wherein: said photoresponsive means is included in said sensing means and said light source is fixed with respect to said movable sensing means.

5. The converter of claim 2 wherein: said photoresponsive means comprises two photocells, one of which is responsive to the actuation of said shutter, and the other which is actuated independently of said shutter.

6. The signal converter of claim 5 wherein: a rotatable drum is positioned between said light source and said photocells in a plane perpendicular to the light path to each photocell and having apertures therein to permit light periodically to pass between said light source and said photocells.

7. The signal converter of claim 6 wherein: means is provided to rotate said drum so that one of said apertures will permit light to pass from said light source to said photocell as said sensing means passes through a predetermined number of locations said settable member so as to indicate when said sensing means moves from one settable member to the next.

8. The signal converter of claim 7 wherein: said apertures in said rotatable drum include two sets of apertures which are perpendicularly disposed with respect to each other.

9. The signal converter of claim 8 wherein: one set of said apertures in said drum are related to said shutter means and are wider than the other set of apertures in said drum.

10. The signal converter of claim 9, including: a rack parallel to the axis of said settable means, and a gear which is connected to said drum, and meshes with said rack so that said drum is rotated when said sensing means to moved parallel to said settable means.

11. The signal converter of claim 10 wherein: said settable means comprises a plurality of rotatable gears, said grooves are located between the teeth of said gears, and wherein said reference line passes thru the center of each of said gears.

12. The signal converter of claim 11, including: 10 teeth on each gear with spaces therebetween and 10 grooves, one in each space, which grooves represent the digits 0-9.

13. The signal converter of claim 12 wherein: the grooves are coded according to a binary code comprising five bits.

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