Abstract:
The specification discloses a woodworking and home improvement calculator particularly adopted for symplifying common home improvement calculations. The calculator includes a variety of special keys including a gravel, cement, tile, brick, block, 4×8 sheet, paint, wallpaper, stud and roof bundle keys which allow the user to quickly determine the amount of materials needed for projects involving the aforementioned keys.

Description:
This application is submitted in the name of inventors Michael A. Diamond, Steven C. Kennedy, Joel S. Novak and Kenneth M. Steiner assignors to Calculated Industries, Inc., a Nevada Corporation. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to calculators, and more particularly to calculators especially adapted to perform calculations and conversions of dimensional data for woodworking and home improvement. 
     2. The Prior Art 
     Many calculators have been developed to perform calculations on dimensional data. One such calculator is the Construction Master IV manufactured by Calculated Industries, Inc. of Carson City, Nev. However this calculator is targeted to construction professionals and is focused towards the necessary calculations those individuals must make in estimating and bidding complex construction projects. 
     Various dimensional calculators are illustrated in U.S. Pat No. 4,744,044, issued May 10, 1988 to Stoker et al, entitled HAND HELD CALCULATOR FOR DIMENSIONAL CALCULATIONS; U.S. Pat. No. 4,488,250, issued Dec. 11, 1984 to Lipsey et al, entitled HAND HELD CALCULATOR FOR PERFORMING CALCULATIONS IN FEET, INCHES AND FRACTIONS; U.S. Pat. No. 4,100,603, issued Jul. 11, 1978, to Boyd, entitled FEET, INCHES AND SIXTEENTHS ADDER; U.S. Pat. No. 4,081,859, issued Mar. 28, 1978, to Goldsamt et al, entitled ELECTRONIC CALCULATOR FOR FEET-INCH-FRACTION NUMERICS; and U.S. Pat. No. 3,973,113, issued Aug. 3, 1976, to Goldsamt et al, entitled ELECTRONIC CALCULATOR FOR FEET-INCH-FRACTION NUMERICS. However, none of the above the above are focussed on simplifying calculations specifically for the do it yourselfer. 
     SUMMARY OF THE INVENTION 
     The aforementioned problems are overcome in the present invention comprising a calculator particularly adapted for easily and rapidly performing calculations for typical home improvement projects. The calculator includes multiple material conversions dealing with a variety of home projects. The conversions include: gravel, tile, brick, block, 4×8 sheets, paint, wallpaper, board feet, stud spacing and roofing. Further objects and advantages of the invention will become apparent from a consideration of the drawings and the ensuing description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings which illustrate the best modes presently contemplated for carrying out the present invention: 
     FIG. 1 is a plain view of the calculator keyboard and display; 
     FIG. 2 is an enlarged view of the calculator display showing all of the actual display segments; 
     FIG. 3 is a chart showing the basic operation of the calculator; 
     FIG. 4-24 are flowcharts illustrating the operation of the inventive features of the calculator. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Those of ordinary skill in the art will realize that the following description of the present invention is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons. 
     A calculator constructed in accordance with a preferred embodiment of the invention is illustrated in FIG.  1  and generally designated  10 . The calculator includes a keyboard or other input means  12  and a display or other display means  14 . 
     I. KEYBOARD 
     The keyboard  12  includes several groups of keys including power and clear keys  16 , numeric keys  18 , measurement keys  20 , a conversion key  22 , and a percentage key  24 . Secondary functions are accessed through the numeric keys  18  and are displayed on the calculator housing  26 . 
     The power/clear keys  16  are conventional and are used to turn the calculator on and off and to clear the display and/or clear memory. The [On/C] or On/Clear Key turns power on. Pressing once clears the display. Pressing twice clears all temporary values. The [Off] or Off key turns all power off, clearing all non-permanent registers. The numeric keys  18  are conventional and used to input numeric information and include the conventional numeric keys 0-9 and a decimal point (.). 
     Dimensional keys  20  are conventional and are used to label or convert entered values into appropriate dimensional values. To label a dimension as “square” or “cubic,” the value is entered and then the desired key is pressed twice to square and three times to cube. For example, to enter 25 cubic yards, the user presses 25 [Yds] [Yds] [Yds]. To enter 25 square feet, the user presses 25 [Feet] [Feet]. The yard [Yds] key (as stated) enters or converts to yards. The feet [Feet] key enters or converts to feet as whole or decimal numbers. This key is also used with the [Inch] and [/] keys for entering Feet-Inch values (e.g., 6 [Feet] 9 [Inch] 1 [/] 2). Arithmetic operation keys  28  and their secondary conversion function labeled on the housing above the keys are conventional and are used to engage in conventional calculator functions such as addition, multiplication, subtraction and division. The secondary functions include squaring input numbers, taking the square root, changing the value to + or − as well as recalling memory values “MR” and adding values to memory “M+.” 
     The Inch [Inch] key enters of converts to inches. Entry can be whole or decimal numbers. This key can also be used with the [/] key for entering fractional inch values (e.g., 9 [Inch] 1 [/] 2). Repeated presses during conversions toggle between fractional and decimal inches. The Meter [Met] key enters or converts to meters. The fraction bar [/] key is used to enter fractions. Fractions can be entered as proper (½, ⅛, {fraction (1/16)}) or improper ({fraction (3/2)}, {fraction (9/8)}). The calculator is set to display fractional values to the nearest 16th of an inch. {fraction (1/64)} resolution can be displayed by pressing [/] with the value in the display. The fractional resolution can be permanently set by pressing [Conv][/] with a clear (zero) display. Repeat presses of the [/] key will then revolve through the available settings: {fraction (1/16)}, {fraction (1/32)}, {fraction (1/64)}, ½, ¼ and ⅛. 
     II. DISPLAY 
     The calculator display  14  is illustrated in greater detail in FIG.  2 . The display includes a decimal display  50 , a fractional display  52 , a conversion indicator  54 , a memory indicator,  56  and measurement annunciators  58 . The preferred decimal display  50  includes seven digits, each comprising a seven-segment display, for displaying a decimal number including a floating decimal point. Other numbers of digits can be included in the display as desired. The fractional display  52  includes a two digit numerator and a two digit denominator separated by a slash  60 . The alphabetical display includes four characters, each comprising a fourteen segment display. Activation of the memory display  56  indicates that a number is stored in the independent calculator memory. 
     The measurement annunciators  58  include the eight indicators or segments “CU” “SQ” “FEET” “YD” “CM” “MM” “M” “INCH.” These annunciators  58  are activated in response to depression of measurement keys  20  to indicate measurement system information associated with the displayed number. Specifically, the annunciators  58  can be displayed in the following combinations: YD, FEET, MM, CM, M, INCH, FEET INCHES, SQ YD, SQ FEET, SQ MM, SQ CM, SQ M, SQ INCH, CU YD, CU FEET, CU MM, CU CM, CM and CU INCH. All of the displays  50 ,  52 ,  54 ,  56 ,  58  and  60  are generally well known to those having ordinary skill in the construction calculator art. 
     III. OPERATION 
     The calculator includes conventional circuitry responsive to the keyboard  12  for receiving input and performing calculations. The input number or measurement is displayed on the display  14 ; and the results of all calculations are also displayed on the display  14 . The software for implementing the function of the calculator can be readily prepared by one having ordinary skill in the art in view of the present specification, particularly the flow charts of FIGS. 3-24. 
     The calculator is “key driven” or “keyboard driven”, meaning that the internal operation of the calculator is dependent upon the last key entered. Major branching decisions within the software are made on the basis of the most recent key entry. Numeric input is entered using the numeric keys  18 . Additionally, measurement information associated with the numbers can be inputted using the measurement keys  20 . The operation of the calculator in modes and functions not described below, will not be described in detail inasmuch as such operation is generally identical to conventional calculators and more specifically prior art construction calculators. 
     In FIG. 3, the block diagram circuit arrangement for the calculator of the present invention  10  is set forth. The circuit includes a microprocessor  300  containing a display register  310 , a memory  320 , an accumulator  330 , and an entry register  340 . The microprocessor  300  is interconnected over bus  350  to the keyboard keys  20 . The microprocessor  300  communicates over bus  380  with drivers  390 . The drivers  390  communicate over bus  392  with the display circuit  14 . A battery power supply  395  provides power over lines  397  and  399  to the drivers  390  and to the microprocessor  300  respectively. Persons of ordinary skill in the art will readily be able to configure a calculator according to the present invention using commercially available components. 
     Gravel Function 
     Referencing FIGS. 4 and 5, shown are flowcharts which detail the basic operation of the gravel function. The gravel function is accessed through the [Conv] [0] keys. The user enters (or calculates to) a cubic dimension. Next the [Conv] [0] key is pressed  400 . The calculator queries whether the entered dimension is in a cubic format  405 . If not, an error message is displayed  410 . If the value is properly entered in a cubic format, the calculator converts the entered cubic value to a tonnage value based on a default conversion factor  415 . The calculator then displays the appropriate tonnage  420  along with the indicator “tn.” 
     The calculator also calculates the reverse, i.e., an entered tonnage into a corresponding cubic coverage. The user simply enters the number of tons and accesses the gravel function: [Conv] [0]  500 . The calculator converts the entered tonnage into a corresponding cubic yard coverage based on the conversion factor  505  and displays the same using the indicator “CU YD”  510 . The default conversion factor is 0.77 cu. yards of coverage for one ton of gravel or conversely 1.3 tons equals one cubic yard of coverage. 
     Concrete Bags/mix Function 
     Referencing FIGS. 6 and 7, shown are flowcharts which detail the basic operation of the concrete function. The concrete function is accessed through the [Conv] [0] keys. The user enters (or calculates to) a cubic dimension. Next the [Conv] [0] key is pressed  600 . The calculator queries whether the entered dimension is in a cubic format  605 . If not, an error message is displayed  610 . If the value is properly entered in a cubic format, the calculator converts the entered cubic value to a tonnage value based on a default conversion factor  615 . The calculator then displays the appropriate number of cement bags required  420  along with the indicator “bg.” 
     The calculator also calculates the reverse, i.e., an entered number of cement bags into a corresponding cubic coverage. The user simply enters the number of cement bags and accesses the concrete function: [Conv] [0]  700 . The calculator converts the entered bags into a corresponding cubic yard coverage based on the conversion factor  705  and displays the same using the indicator “CU YD”  710 . The default conversion factor is (NEEDED) cu. yards of coverage for each bag of cement or conversely each cubic yard of coverage requires (NEEDED) bags of cement. 
     Tile Function 
     Referencing FIGS. 8,  9  and  10 , shown are flowcharts which detail the basic operation of the tile function. The tile function is accessed through the [Conv] [1] keys. The user enters (or calculates to) a squared dimension  800 . Next the [Conv] [1] key is pressed  805 . The calculator then converts the entered area value to a number of tiles value based on a variety of conversion factors  810 . The calculator then displays the appropriate number of 18 inch tiles required  815 , along with the indicator “ 18  in.” 
     Another press of the tile [1] key  820 , displays the number of 12 inch tiles required for the same entered area  825  along with the indicator “12 in.” Repeated presses of the tile [1] key  830 ,  840 ,  850 ,  860 ,  870  accesses other conversions, i.e., to 8 inch, 6 inch, 4 inch, 2 inch and 1 inch tiles,  835 ,  845 ,  855 ,  865  and  875  respectively. A subsequent press of the tile [1] key  880 , cycles to the top of the information queue  815 . 
     Referring to FIG. 9, the calculator also calculates the reverse, i.e., an entered number of tiles into a into a corresponding square foot coverage. The user simply enters the number of tiles and accesses the tile function: [Conv] [1]  900 . The calculator converts the number of entered tiles into a corresponding square foot coverage based on conversion factors  905  and displays the same using the indicator “SQ FEET” along with the tile size associated with the coverage  910 . Subsequent presses of the tile key  915 ,  925 ,  935 ,  945 ,  955  and  965  reveals coverage for additional sizes  920 ,  930 ,  940 ,  950 ,  960  and  970 . An additional press of the tile key  980  reveals the number of tiles input by the user with the designation “ti”  980 . 
     Referring to FIG. 10 the calculator can also calculate linear tile requirements, i.e., the amount of tiles needed for a linear dimension. The user simply enters the linear dimension into the calculator  1000  and accesses the tile function by pressing [Conv] [1]  1005 . The calculator then calculates the number of tiles required for the entered length for a variety of tile sizes  1010  and displays the number of tiles associated for the first tile size  1015 . Subsequent presses of the tile key  1020 ,  1030 ,  1040 ,  1050 ,  1060  and  1070  display the remaining information  1025 ,  1035 ,  1045 ,  1055 ,  1065  and  1075 . An additional press of the tile key  1080  displays the entered distance for the user with the linear designation  1085 . Another press  1090  simply cycles the calculator to the beginning of the information queue  1015 . 
     Brick and Block Function 
     Referencing FIGS. 11,  12  and  13 , shown are flowcharts which detail the basic operation of the brick and block functions. Referring to FIG. 11, the brick function is accessed through the [Conv] [2] keys. The user enters (or calculates to) a squared dimension  1100 . Next the [Conv] [2] key is pressed  1105 . The calculator then converts the entered area value to a number of face and paver bricks based on conversion factors  1110 . The calculator then displays the appropriate number of face bricks required  1115 , along with the indicator “F br.” 
     Another press of the brick [2] key  1120 , displays the number of paver brick required for the same entered area  1125  along with the indicator “P br.” The block function can be accessed by pressing [Conv] [3] keys  1130  which then converts the previously entered area into the number of block required  1135  and then displays the calculated number, along with the designation “bL”  1140 . 
     The conversion factors used are 21 square inches of coverage for each face brick and 32 square inches of coverage for paver bricks. This is based on a modular U.S. Brick size of 3-⅝ inches ×2-¼ inches ×7-⅝ inches including ⅜ inches of mortar. The block size is 128 square inches which includes ½ inch of mortar. 
     Referencing FIG. 12 the calculator can calculate the reverse as well, i.e., the user can enter a number of bricks or blocks and the calculator indicates the coverage said number of bricks or blocks will enjoy. The user enters the number of bricks and presses the [Conv] [2] key  1200 . The calculator then converts the entered number of bricks using the above conversion factors into a corresponding area  1205 . The calculator then displays the area coverage along with the corresponding brick size: “SQ FEET P br”  1210 , the “P” indicating a paver brick. An additional press of the [2] key  1215  displays the coverage with the other associated brick use: “SQ FEET F br”  1220 . F indicates face brick. Corresponding block coverage can be accessed by pressing the [Conv] [3] key  1225 . The calculator converts the entered number into corresponding block coverage  1230  and displays covered area: “SQ FEET”  1235 . 
     Referencing FIG. 13, corresponding bricks and blocks for an entered linear dimension can be calculated. A linear dimension is input  1300 , then the brick function is accessed by pressing the [Conv] [2] key  1305 . The calculator then converts the input distance into the required number of face and paver bricks  1310  and displays the paver bricks  1315  with the designation “P br.” An additional press of the [2] key  1320 , displays the number of face bricks  1325  with the designation “F br.” Pressing the [Conv] [3] key  1330  converts the entered length into the number of required blocks  1335  and displays that number  1340  with the designation “bL.” 
     4×8 Sheet Function 
     Referencing FIGS. 14,  15  and  16 , shown are flowcharts which detail the basic operation of the 4×8 sheet functions. Referring to FIG. 14, the 4×8 sheet function is accessed through the [Conv] [4] keys. The user enters (or calculates to) a squared dimension  1400 . Next the [Conv] [4] key is pressed  1405 . The calculator then converts the entered area value to a number of 4×8 sheets bricks based on a conversion factors  1410 . The calculator then displays the appropriate number of 4×8 sheets required  1415 , along with the indicator “Sh.” 
     Referencing FIG. 15, the calculator can calculate the reverse as well, i.e., the user can enter a number of 4×8 sheets and the calculator indicates the coverage said number of sheets enjoy. The user enters the number of sheets and presses the [Conv] [4] key  1500 . The calculator then converts the entered number of 4×8 sheets into a corresponding area  1505 . The calculator then displays the area coverage: “SQ FEET”  1510 . 
     Referencing FIG. 16, corresponding 4×8 sheets for an entered linear dimension can be calculated. A linear dimension is input  1600 , then the 4×8 sheet function is accessed by pressing the [Conv] [4] key  1605 . The calculator then converts the input distance into the required number of 4×8 sheets  1610  and displays the number of sheets  1610  with the designation “Sh.” 
     Paint Function 
     Referencing FIGS. 17 and 18, shown are flowcharts which detail the basic operation of the paint function. Referring to FIG. 17, the paint function is accessed through the [Conv] [5] keys. The user enters the number of gallons of paint and presses the [Conv] [5] key  1700 . The calculator then converts the entered number of gallons of paint to an area value based on a conversion factor  1705 . The calculator displays the value in square feet  1710 . The conversion factor is 1 gallon of paint for 350 square feet. 
     Referencing FIG. 18, the calculator can calculate the reverse as well, i.e., the user can enter an area and the calculator indicates the gallons of paint required to cover that area. The user enters or calculates to the area and presses the [Conv] [5] key  1800 . The calculator then converts the area into the corresponding gallons of paint  1805 . The calculator then displays the number of gallons with the indicator “GL”  1810 . 
     Wallpaper Function 
     Referencing FIGS. 19 and 20, shown are flowcharts which detail the basic operation of the wallpaper function. Referring to FIG. 19, the wallpaper function is accessed through the [Conv] [6] keys. The user enters (or calculates) to a desired area  1900  and presses the [Conv] [6] key  1910 . The calculator then converts the area dimension into rolls of wallpaper based on a conversion factor  1915 . One roll covers 56 sq. feet. The calculator displays the number of rolls required to cover the input area with the designation “rl”  1920 . 
     Referencing FIG. 20, the calculator can calculate the reverse as well, i.e., the user can enter a number of wallpaper rolls area and the calculator indicates the area the input rolls enjoy. The user enters the number of rolls and presses the [Conv] [6] key  2000 . The calculator then converts the rolls into an area coverage  2005  and displays that area  2010  with the indicator “SQ FEET.” 
     Stud Function 
     Referencing FIGS. 21 and 22, shown are flowcharts which detail the basic operation of the stud function. Referring to FIG. 21, the stud function is accessed through the [Conv] [8] keys. The user enters (or calculates) a desired linear distance  2100  and presses the [Conv] [8] key  2105 . The calculator then converts the linear distance into number of studs based on a conversion factor  2110 . One stud is required for every 16 inches of length. The calculator displays the number of studs required to cover the input area with the designation “St”  2115 . 
     Referencing FIG. 22, the calculator can calculate the reverse as well, i.e., the user can enter a number of studs and the calculator indicates the length the input studs will cover. The user enters the number of studs and presses the [Conv] [8] key  2200 . The calculator then converts the rolls into an linear distance  2205  and displays that area  2210  with the indicator “FEET.” 
     Roofing Bundle Function 
     Referencing FIGS. 23 and 24, shown are flowcharts which detail the basic operation of the roofing bundle function. Referring to FIG. 23, the roofing bundle function is accessed through the [Conv] [8] keys. The user enters (or calculates) to a desired area  2300  and presses the [Conv] [8] key  2305 . The calculator then converts the area dimension into roofing bundles based on a conversion factor  2310 . One roofing bundle covers 33.33 sq. feet. The calculator displays the number of roofing bundles required to cover the input area with the designation “rf bn”  2315 . 
     Referencing FIG. 24, the calculator can calculate the reverse as well, i.e., the user can enter a number of roofing bundles and the calculator indicates the area the input rolls enjoy. The user enters the number of rolls and presses the [Conv] [8] key  2400 . The calculator then converts the bundles into an area coverage  2405  and displays that area  2410  with the indicator “SQ FEET.” 
     Adjustable Features 
     The calculator can also be designed with an adjustable conversion features for adjusting the default conversion factors used with the above keys. The user can access the conversion key via the [Conv] key in conjunction with another key e.g. the [Conv] [+]. The user accesses the conversion factors by scrolling through the menu with the [+] or [−] minus key and then adjusting those factors to the users liking by keying in the appropriate value on the keyboard. Changeable factors include the gravel weight to volume ratio; concrete weight to volume ratio; tile with a “grout/no grout” option; i.e., the tile area can be calculated with or without grout. The brick area can be calculated with “mortar/no mortar.” The paint gallon to coverage area ratio can be adjusted. The wallpaper roll to area ratio can also be adjusted as well as the stud spacing. 
     The calculator can also be designed with scrollable choices for the user to select from a variety of gravel weight to volume ratios and concrete weight to volume ratios. Additionally, the calculator can be designed to calculate and display additional concrete values such as amount of aggregate, sand, water and lime required for an input cubic volume. 
     It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than the foregoing description, and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.