US3002683A - Grade averaging computer - Google Patents

Description

Oct. 3, 1961 i P. MXROWLAND 3,002,683

.GRADE AVERAGINQ COMPUTER Filed Nov. 15. 195'? v 2 sheets-sheet 1 F/G 2 f5 u 6 H6 6 A ,3 F/G 7 A 7 ran/vtr.:

Oct. 3, 1961 P. M.RowLAND I 3,002,683

GRADE AVERAGING COMPUTER Filed NOV. 15. 1957 2 Sheets-Sheet 2 J/vvE/vroe PAUL 'M @0n/LAND United States Patent 3,002,683 GRADE AVERAGING CGMPUTER Paul M. Rowland, 416 W. North St., Warrensburg, Mo. Filed Nov. 15, 1957, Ser. No. 696,834 1 Claim. (Cl. 23S-83) This invention relates to computing devices, and more particularly to a device for obtaining the average of a number of grades. t

A main object of the invention is to provide a novel and improved grade average computer which is simple in construction, which is easy to operate, and which provides a means of rapidly and accurately determining the average of a number of alphabetical grades.

A further object of proved grade average computer which is inexpensive to manufacture, which is compact in size, which is durable in construction, and which is especially useful for teachers and instructors for finding the final average grade for a student from several alphabeticalv letter grades, or for otherwork, such as in connection with tests and measurements. f

Further objects and advantages of the invention will become apparent from the following description and claim, and from the accompanying drawings, wherein:

. FIGURE l is a top plan view of an improved average` grade computer constructed in accordance with the present invention. l

` FIGURE 2 is a vertical cross sectional view taken on the line 2-2 of FIGURE 1. t

FIGURE 3 is a top plan view of the ratchet disc mem-` ber `employed in the average grade computer of FIG- URESlandZ. f

FIGURE 4 is a top plan view of the device of FIGURE 1 with the top cover and ratchet disc removed.

FIGURE 5 is an enlarged perspective view of-themanually t perated stop lever employed in the grade average computer of FIGURESlto 4. f f j FIGURE 6 is an venlarged cross sectional detail view taken on the line 6--6Vof FIGURE 4.

pFIGUREr7 isan enlarged cross' sectional detail view taken on the line 7--7 of FIGURE. y

Referring to.the. drawings, the grade `average, computingdevice ,is designatedgenerally at 11 vand comprises a generally circularLbase. 12,having an upstanding` periph-` eralwall 13which detines al generally.. circular recess in the base. .Thebaseis rformed vwith a laterally extending thickened portion 14 which merges with the upstanding peripheral -wall 13, as is clearly shown in FIGURE :4, said "thickened yportion 14 ,defining ,ai projectionat one side of the base whichmaybe employed as a holding means for thefcomputer. Opposite the enlarged side portion14,A the base 12 is formed with a generally V-shaped recess 15 lwhich includesthecenterof the base, as shown in FIGURE 4. Designated at 16'is an arm which is disposed in the recess 15, the arm being substantially dat, as shown,and being pivotally engaged-on an upstanding central` stud -17 provided on the base, .the recess 15 being arcuately formed atits inner-end,.as shown at.18, and the arm 16being similarlyarcuately formed at 19 so that the armiis freely. rotatable `through the angle dened by the generally V-shapedrecess 15. l

Arm-16 is formed with the outwardly projecting, reduced operating `lug 20, said lug being providedrwith a radially'extending index mark 21 `located outwardly adjacent theperiphery of baseY 12. Mounted on the arm 16 adjacent the periphery of the base 12 Yis a resilient pawl spring" 22, said spring projecting inwardly and upwardly, as viewed in FIGURE 4,` whereby it is yieldabler when the arm4 ismoved in a downward direction but is relatively rigid when the arm is moved upwardly, as will bepresent-VVV 1y described.

the invention is to provide an imice i Y 2 Designated at 23 is a resilient pawl member which is embedded in the thickened portion 14 and which projects into the generally circular recess defined on the base 12 by the peripheral wall thereof, the leaf spring member 2?V extending downwardly and inwardly into said recess, as is,

clearly shown in FIGURE 4, whereby it is yieldable in one direction and substantially rigid in another, as will be further described.

' Designated at 24 is a ratchet disc which is rotatably received in the circular recess defined in the base 12, ratchet disc 24 being formed with a central stud portion 25 which is centrally recessed at its bottom surface to rev 28.` Said rim member 27 lis further formed with the evenly kspaced ratchet teeth 28 which are engageable by thepawl members 22 and 23, whereby the pawl member 23 is yieldable when the kdisc member 24 rotates in a counterclockwise direction, as viewed in FIGURES 3A `and 4, the pawl`rnember 23 acting to prevent clockwise rotation of the disc member 24. The pawl member 22 on the arm 16 is arranged to drivingly engage the ratchet teeth 28, whereby the disc member 24 may be rotated in -a counterclockwise direction by rotating the arm 16 in said direction, using the handle element 20. The ,arm 16 may be returned in a clockwise direction, as viewed in FIG- URE 4, without rotating the disc member 24, since the pawl spring 22 is yieldable to allow arm 16 to rotate clockwise relative to the ratchet disc 24.

Designated at 29 is a manually operated locking lever, comprising a at body 30 formed at one end with an arcuate detent shoulder 31 having a curved cam-like leading edge 45 and at its other end with an upstanding stud 32. Thelever 29 is pivoted at its intermediate portion to the base 12 adjacent theperipheral wall 13, the peripheral wall being arcuately notched at 33kto allow clearance for the outer end of lever 29, as shown iny FIGURE 4. The body 30 of the locking lever 29 lies in a generally circular recess 43 in base 12 and extends beneath the rim 27'of the disc' 24, and the detent shoulder 31 extends upwardlyand inwardly adjacent the internal shoulder 28'. Said internal shoulder is formed with an inwardly projectformed yin the detent shoulder 31, whereby the disc 24 i '1 will be held against counter-clockwise rotation when lug 34 engages the shoulder 35, as viewed in FIGURE 4. By manually rotating the lever 29 in a counter-clockwise direction, as viewed in FIGURE 4, from the full line position thereof tothe dotted view position thereof, the trailing end 47 of shoulder 35 may be moved inwardly'sufficiently to allow the lug 34 to clear same.

{'Ihe locking lever 29, in its full line position, shown in FIGURE 4, establishes the starting position of the ratchet disc 24. v

Designated at 36V is an opaque cover member rwhichis secured on the base 12 in overlying relationship to the disc member 24, said cover member 36 being formed with a central aperture through which the stud member 25 freely extends, as is clearly shown in FIGURE 2. The

` cover member 36 is of identical shape tol-the base 12, as

shown lin FIGURES 1 and 2.

The ratchet disc 24 is inscribed with a ,plurality of concentric rows of alphabetical letter grade ,marks, said rows being shown at 37. The angular spacing between adjacent grade letters of said rows is exactly the same as Patented Oct. 19,61`

the angular spacing between adjacent ratchet teeth 28 of the disc.

The cover member 36 is formed with the radially extending window or aperture 38 which transversely overlies vthe vrows of grade marks 37, the side margin of window 38 being provided ,with a scale 39 identifying the respectiverows, in terms of numerals representing the number of grades whose average is to be taken.

The cover member 36 is further inscribed adjacent the handle 20 o=f the operating arm 16 with a grade scale 40, comprising the series of grades whose average may be computed, the grades being arranged in descending order, as shown in FIGURE l, and being spaced along the periphery of the cover 36 by the same angular spacings as the ratchet `teeth 28, the rst grade calibration 41 being spaced from the index line 21 of the handle Ztl, with the handle in its zero position in recess 15, by a spacing equivalent to the angular spacing between two successive ratchet teeth 28. The rows of grade marks 37 comprise grade marks calibrated in'accordance with the sum of the number of ratchet teeth moved by the arm 16 during a series of rotations of the disc member 24 and in accordance with the number of such rotations. Speciiically, each grade mark value in the rows 37 is determined by dividing the sum of the number of ratchet teeth moved by the arm 16 during a series of rotations of the disc rnember24 by the arm 16 by the number of such rotations, the numerical value thus obtained being correlated with an alphabetical grade value in a manner readily understood. Thus, in computing an average grade, the user successively rotates the disc member 24 through angles corresponding to the various grades to be averaged, each grade being included in the total to be averaged by moving knob 21 in a counterclockwise direction, as viewed in FIGURE l, from the starting position to a calibration 41 corresponding to said grade, and then returning the knob 20 -to its starting position. As will be readily apparent, such a movement of -the operating element 20 rotates the disc member 24 through a number of ratchet teeth angles, corresponding to the particular grade included in the total to be averaged. Since each particular grade represents a specific number of ratchet teeth, the total of all the grades will be represented by a total number of ratchet teeth which in turn corresponds to a specic amount of angular rotation of the disc member 24 in a counterclockwise direction from its starting position. The average number of ratchet teeth is determined by dividing the total by the number of actual rotations required to produce the total. The grade values 37 represent, in terms of alphabetical symbols the quotient of the .total number of ratchet teeth divided by the number of rotations involved in the computation. Thus, the scale numerals 39 represent various numbers of rotations, namely, various numbers of grades to be averaged, and in the specific example illustrated represent from two to eight grades -to be averaged, the respective rows of concentric scales on the disc member 24 being calibrated to provide the quotient of the total numerical value (number of ratchet teeth) divided by number of rotations (number of grades to be averaged), translated into alphabetical symbols. Thus, to obtain a grade average, it is merely necessary to rotate the operating arm 20, as above described, through the successive angles, corresponding to the various grades, and then to determine theaverage by observing the value appearing next to the scale numeral 39 adjacent window Si; corresponding to the number of grades included in the computation. The average grade will be given adjacent the scale numeral 39 adjacent window 38.

After an average has been obtained, as above described, the disc member 24 may be returned to its starting position by rotating the enlarged top end of the stud 25, shown at 40', in a counter-clockwise direction, until the lug element 34 engages the detent shoulder 35 on the locking lever 29. IThis quickly establishes the starting position of disc member 24. The disc member may be released for use in a computation by rotating the locking lever 29 in a counter-clockwise direction suiciently to allow lug 34 to clear end portion 47, namely, from the full line view position thereof shown in FIGURE 4 to the dotted View position thereof, by means of the upstanding stud element 32 which projects through a slot 42 provided in the cover 36. After a compu-tation, the disc member may be rotated suiiiciently to cause the lug 34 to engage the leading edge portion 45 of the shoulder 31, thereby causing the locking lever to return to its normal locking position wherein the lug 34 is received in the notch 35, thus reestablishing the starting position of the disc member after the averaging computation.

VAs 4will be readily understood, the locking lever 29 engages between the bottom surface of the recess 43 and the top cover 36 with suiiicient friction so that it must be manually rotated from its locking position to its release position.

The average grade marks 37 on the respective concentric rows of grade marks on disc member 24 represent transfer values corresponding to the grades being averaged, wherein the ratchet teeth are employed as the transfer means. Thus, in the calibration of the numerical value 37, the original grades may be assigned tooth values corresponding to their particular significance. For example, the alphabetical grade A represents one tooth, the alphabetical grade A- represents two ratchet teeth, the alphabetical grade B+ represents three teeth, the alphabetical grade B represents four teeth, etc. A series of additions of alphabetical grades, causes the disc member 24 to be rotated through a number of ratchet teeth angles, corresponding to the sum of the assigned values of the respective grades included in the computation. The sum of the ratchet teeth, divided by the number of rotations involved, would provide a numerical value, which is expressed as an alphabetical grade value, in accordance with the original assignment of numerical values for the respective grades.- Where the quotient of the total number of teeth divided by the number of computations is intermediate between one numerical value and another, the corresponding alphabetical grade may be expressed by two alternative grade values, as shown in certain of the spaces in the concentric rows illustrated in FIGURE 3, whereby the teacher is given the discretion of assigning one or the other alphabetical grade value to the pupil in question.

The disc member 24 is suitably shaded, as shown at 44, to notify the user when the starting position is being approached, as the knob 40 is rotated toward said starting position, the shaded area 44 appearing through the Window 38 as the disc 24 approaches its starting position.

While a specic embodiment of an improved device for obtaining the average of a number of alphabetical grades has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claim.

Whatis claimed is:

A device for obtaining the average of a number of grades comprising a base, a disc member pivoted centrally on said base andv being inscribed with a plurality of concentric rows of grade marks, evenly spaced ratchet teeth on the periphery of said disc member, said base being formed with a generally V-shaped recess which includes the center of the base adjacent the vertex of the recess, a substantially flat arm disposed horizontally in said recess beneath the disc member and pivoted to the center ofthe base in said recess on the same axis as said disc member and projecting radially beyond an edge of saidV base, pawl means on the arm adjacent the periphery of the base. engageable with said ratchet teeth to rotate the discV member in one direction responsive to rotation of said arm in said one direction, second pawl means being calibrated in accordance with a value determined by dividing the sum of the number of ratchet teeth moved by the arm during a series of rotations of the disc member by the number of such rotations, said cover member being provided adjacent said arm with a scale of radial y markings corresponding to the different grades and angularly separated by the same angular spacing as the successive ratchet teeth, a reset knob centrally secured to said disc member and extending through said cover member, and manually releasable cooperating detent means on the base and on the disc member formed and arranged'k to at times prevent rotation of` said disc member beyond member, a detent arm pivoted to said base and having a detent notch lockingly engageable with said lug, and means to manually rotate said detent arm` suiciently to disengage said detent notch from said detent lug. y

` References Cited in the file of this patent UNITED STATES PATENTS 640,850 work Jan. 9, i900 748,924 Buresh l.'an. 5, 1904 1,729,714 Ellison Oct. 1, 1929 1,765,697 Palmer et al June 24, 1930 FOREIGN PATENTS 819,737 Germany Nov. 5, 1951 286,168 Switzerland Feb. 2,

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