Abstract:
A specialized dimension proportioning hand-held calculator designed specifically for computing percent reductions of photographs in the graphic arts field. The calculator computes the percent reduction from an original width or height of the photograph and from the desired reduction width or height in decimal notation and fractional notation. The calculator also is designed to perform basic mathematical functions. The calculator is generally comprised of a mode selection device, a numerical keyboard, a keyboard display, a percent reduction display, a power cell, and four display cells comprised of decimal and fraction displays, an enter key, a constant key, and a display cell clear key. The calculator components are encased in a generally hard, rectangular casing. Power for the calculator is supplied by the power cell.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to dimension proportioning hand-held calculators and, in particular, to a hand-held calculator for use in electronic graphic arts proportioning. 
     A significant task in the graphics arts profession involves enlarging and reducing graphic material to fit within definite reproducible spacing. It will be understood by those skilled in the art, that the present invention exhibits utility for electronically determining proper proportional sizing of any piece of reproducible graphic arts. For purposes of brevity, but not to be limited by, photographs shall serve as examples hereinafter. Currently, graphic artists utilize a hand-held manually operated wheel to obtain the percentage reduction or enlargement needed for a photograph, and then rely upon a conventional electronic calculator for arithmetic computations. The conventional graphic arts proportional wheel can be inaccurate, difficult to read, and hard to interpolate. Although electronic hand-held calculators have been specially designed for specific purposes in other fields, graphic artists still use the manual method due to the lack of an electronic proportional calculator for virtually instant determination of percentage reductions or enlargements required. 
     Conventional hand-held electronic calculators for measurement input or output are represented by U.S. Pat. No. 4,181,959 to Iwao Tateishi issued on Jan. 1, 1980 for a combined electronic digital scale and calculator with memory, U.S. Pat. No. 4,181,960 to Iwao Tateishi and Nobuyasu Kakutani issued on Jan. 1, 1980 for a combined electronic digital scale and calculator, and U.S. Pat. No. 4,195,348 to Nobuyasu Kakutani issued on Mar 25, 1980 for an electronic digital scale and calculator with selectable programs, and U.S. Pat. No. 4,488,250 to William Lipsey and Henry Teague issued on Dec. 11, 1984 for a calculator for performing calculations in feet, inches and fractions. Conventional hand-held calculators designed for other non-measurement, but computational, purposes are represented by U.S. Pat. No. 4,486,849 to Isao Harigaya and Akihiro Yamataka issued on Dec. 4, 1984 for a computer for calculating compound interest, U.S. Pat. No. 4,446,528 to Robert Marmon issued on May 1, 1984 for a shoppers calculator. 
     These representative conventional electronic calculators would be either incapable of use, or extremely cumbersome in use, for determination of percentage reduction and enlargement measurements in the graphic arts industry. When faced with the task of reproducing a photograph, for example, the graphic artist begins with an original work and a space into which the original work is to be inserted in the production copy. Thus, to determine the degree of reduction or enlargement, the artist will know the original height and width dimensions, and will know either the reproduction height or width restraints imposed by the position required for the reproduction. In order to make a proper determination of reproduction sizing, the artist must know at least three of these four values. Moreover, due to the high volume of reproduction work required of the graphic artist, it has been found desirable to have a calculator capable of variable entry, calculation and display, in both decimal and fraction values, variable entry of any three of the four height and width values and automatic calculation of the percentage reduction or enlargement required, based upon the variable entry of the height and width values. It will be understood by those skilled in the art, that the prior art does not include a hand-held calculator specifically adapted for easy use in electronic graphic arts proportioning. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an electronic hand-held calculator to calculate percentage reductions and enlargements of graphic arts material for reproduction. 
     It is also an object of the present invention to provide an electronic hand-held calculator capable of displaying an original width and height, a reproduction width and height, and the percentage reduction or enlargement required for reproduction. 
     It is another object of the present invention to provide an electronic hand-held calculator which can operate using constants and variables while calculating percentage reduction or enlargement. 
     It is further an object of the present invention to provide an electronic hand-held calculator capable of conventional calculating and calculating graphics arts proportions. 
     These and other objects, features and advantages of the present invention, hereinafter disclosed, will become more apparent from the following, more detailed, description of the present invention with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top elevational view of a proportional graphic arts calculator according to the present invention. 
     FIG. 2 is a schematic flow diagram of the operating process of the electronic proportional graphic arts calculator according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the accompanying drawings, and in particular with reference to FIG. 1, there is shown a calculator 10 used to calculate the percent reduction or enlargement of a photograph. The calculator 10 consists generally of a keyboard 12, a plurality of display cells 48, 50, 52 and 54, a power source 66, and a casing 16. 
     The keyboard 12 consists generally of a number keyboard 18 having a plurality of numerical keys numbered 0 to 9 and decimal point, a mode display 22, a fraction keyboard 24 with a plurality of fraction keys of 1/16 increments, a primary entry display 26, a primary entry display cancel key 28, a percentage display 30, and an all clear key 32. The primary entry display 26 further comprises a decimal numerical display 44 and a fraction numerical display 46 consisting either of a unitary display or separate display for fraction numerators and fraction denominators and may have, as an alternative embodiment of the present invention, a function keyboard 20 with addition, subtraction, multiplication, division, and an &#34;=&#34; function keys. It will be appreciated by those skilled in the art, that each of the foregoing displays may consist of any conventional display means including, but not limited to liquid crystal displays or light emitting diodes. 
     The preferred embodiment of the mode display 22 comprises mode status displays for each of a proportional calculator fraction (pro cal frac) mode 34, a proportion calculator decimal (pro cal dec) mode 36, a calculator fraction (cal frac) mode 38, and a calculator decimal (cal dec) mode 40. Each mode is selected by activating a mode select key 42 operatively connected to each mode status display. The pro cal frac mode 34 allows the operator to operate in fractions when calculating the percentage reduction or enlargement of a photograph. The pro cal dec mode 36 allows the operator to use decimals when calculating the percent reduction of a photograph. The cal frac mode 38 and the cal dec mode 40 allows the operator to operate the calculator in fractions and decimals respectively when using the function keyboard 20. 
     An alternative embodiment of the mode display 22 comprises a mode select key 42 which operatively activates to one of a proportional decimal or a proportional fraction mode display. 
     The function of the primary entry display cancel key 28 is to cancel any number displayed on the primary entry display 26 and reset the primary entry display 26 to zero. The function of the all clear key 32 is to clear all displays on the calculator 10 except when the constant key 62 has been pressed. 
     The plurality of display cells 14 consists generally of a display cell 48 for the original width to be reproduced, a display cell 50 for its original height, a display cell 52 for the reproduction width, and a display cell 54 for the reproduction height. The display cell 48, the display cell 50, the display cell 52, and the display cell 54 have an enter function key 60, an enter constant key 62, and a display clear function key 64. Each display cell further comprises decimal numerical display 56 and the fraction numerical display 58. 
     The enter key 60, when pressed, takes a value registered in the keyboard display 26 and enters that value in either the decimal display 56 or the fraction display 58 depending upon whether the user has selected the decimal or fraction mode. The display cell clear key 64 resets the decimal display 56 and the fraction display 58 in its corresponding display cell to zero. 
     The constant key 62 is designed for calculating percentage enlargement or reduction for constant dimensions of either the original or reproduction. When the constant key 62 of a display cell 50 is pressed, the value displayed in the decimal display 56 and the fraction display 58 of that display cell can only be cleared by means of the corresponding display clear function key 64. Pressing the all clear key 32 will not reset the decimal display 56 and the fraction display 58 to zero in a particular display cell if the constant key 62 in that display cell is actuated. 
     The preferred embodiment of the power source 68 comprises a conventional solar cell. The function of the power source 68 is to provide operating power to the electronic hand-held calculator 10. However, any suitable AC or DC power source may be utilized. 
     OPERATION OF THE PREFERRED EMBODIMENT 
     Referring in particular to FIG. 2, there is shown a flow schematic of the operation of calculator 10. A decimal memory 110 stores values for the number keyboard 18 and a fraction memory stores values for the fraction keyboard 24. When the pro cal dec mode 36 or the cal dec mode 40 is activated, the calculator will only accept values from the decimal memory 110. When the pro cal frac mode 34 or the cal frac mode 38 is activated, the calculator will accept values from both the decimal memory 110 and the fraction memory 112. 
     A percentage reduction or enlargement path 114 is activated when the pro cal dec mode 36 is activated, or when the pro cal frac mode 34 is activated. The percentage reduction or enlargement path 114 calculates the percentage reduction or enlargement of a photograph from the values entered in the display cells 52 and 48, or in the display cells 50 and 54 by means of the following steps: 
     (1) a value (1) is entered into the keyboard display 26 by means of the number keyboard 18 and the fraction keyboard 24, or by means of the number keyboard 18 only; 
     (2) value (1) is entered into a display cell (e.g. the display cell 48 for original width) from the keyboard display 26 by pressing the enter key 60 or the constant key 62 of that display cell into which value (1) is to be entered; 
     (3) value (1) is displayed on the decimal display 56 and the fraction display 58, and is stored in a display cell memory 116 for the corresponding display cell; 
     (4) if value (1) is not correct or needs to be changed, the decimal display 56, the fraction display 58, and the display cell memory 116 are reset to zero by means of the display cell clear key 64, and a new value must be entered from the keyboard display 26; 
     (5) a value (2) is entered into the keyboard display 26 by means of the number keyboard 18 and the fraction keyboard 24, and the value (2) is then entered into a display cell (e.g. the display cell 52 for reproduction width) by means of the enter key 60 or the constant key 62 for the corresponding display cell; 
     (6) value (2) is displayed in the decimal display 56 and the fraction display 58 and is stored in the display cell memory 116 for the respective display cell; 
     (7) value (2) may be cleared from the decimal display 56, the fraction display 58, and the display cell memory 116 by means of the display cell clear key 64, and a new value must be obtained from the keyboard display 26; 
     (8) a central processing unit (CPU) 118, such as a CMOS microprocessor, automatically retrieves the value (1) and the value (2) stored in the display cell memory 116, and calculates a percentage reduction (% red) or enlargement required according to the following formula: ##EQU1## wherein the Reproduction Dimension and the Original Dimension are dependent upon which height and width values are known. For example, if the original width and reproduction width are known, the percentage reduction or enlargement is expressed by the formula: % red=(w 1  /w 2 )×100; where the original height and reproduction height are known, the percentage reduction or enlargement is expressed by the formula: % red=(h 1  /h 2 )×100 wherein h 1  and w 1  represent the height and width values of the original work, and h 2  and w 2  represent the height and width values of the reproduced work; 
     (9) the percent reduction is registered on the percent reduction display 30. 
     In operation, the CPU 118 scans the inputs from the number keyboard 18, the fraction keyboard 24, the mode keyboard 22, and the display cell keys in order to determine the status of each of the keys. If any key has been pushed, the CPU moves that information into the appropriate entry register and performs computational operations on it which conventionally includes use of the decimal memory 110 and the fraction memory 112 and displays the appropriate information conveyed by the key into the corresponding display. 
     The CPU 118 calculates percentage reduction or enlargement for values of width or for values of height, but the CPU 118 will not calculate percentage reduction if there is only one value of width and one value of height. For example, a percentage will be calculated from a value (1) entered into the display cell 52 and a value (2) entered into the display cell 48, but will not calculate a percent reduction from a value (1) entered into the display cell 52 and a value (2) entered into the display cell 50 if there are no other values entered into display 14. If there is a value (1) entered into the display cell 52, a value (2) entered into the display cell 48, and another value (3) entered into either the display cell 54 or the display cell 50, the CPU 118 will calculate the percent reduction or enlargement from the values entered into the display cell 52 and the display cell 48, and will calculate a missing value (4) and display the value (4) in either the display cell 54 or the display cell 50, whichever did not have a value entered originally. Similarly, the CPU 118 will calculate a missing value (4) when values (1) and (2) are entered into both the display cell 50 and the display cell 54 and a value (3) is entered into either the display cell 52 or the display cell 48. 
     A calculator path 120 is activated when the cal dec mode 40 or the cal frac mode 38 is activated. The calculator 10 operates similar to a conventional mathematical calculator by means of the following steps: 
     (1) a value is entered into the keyboard display 26 by means of the number keyboard 18 and the fraction keyboard 24, or by means of the number keyboard 18 only; 
     (2) the operator selects the appropriate function from the function keyboard 20; 
     (3) consecutive values and functions are pressed as appropriate; 
     (4) an equals key 70 on the function keyboard 20 is pressed to end the calculation and tally the answer by means of the CPU 118, and the answer is displayed in the keyboard display 26. 
     According to an alternative embodiment of the present invention, the mode keyboard 22 does not require the operator to activate a specific mode in order to activate the percentage reduction enlargement path 114 or the calculator path 120. Rather, the percentage reduction or enlargement path 114 is activated automatically when values from the keyboard display 26 are entered into the display cell 48 and the display cell 52, or into the display cell 54 and the display cell 50. In this manner, calculator path 120 is continuously activated. The mode key 42 allows the operator to change from decimal only computations to computations using both decimals and fractions, and back to decimal only computations. 
     While the invention has been particularly shown and described in reference to the preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made without departing from the spirit and scope of the invention.