US2193929A - Automatic calculation apparatus - Google Patents

Description

March 19, 1940. K. s. LION AUTOMATIC CALCULATION APPARATUS Filed Feb. 25, 1937 mql.

lllllllll llllljll|| lllll] l INVENTOR ffimf fibyflzed Lion ATTORNEY Patented Mar. 19, 1940 UNITED STATES PATENT OFFICE 2 Claims.

10 distance, thicknesses of filters, loads of tubes, and

the like.

Until now, the determination of these values has had to be efifected by means of tables, curves,

nomograms, and slide rules, a procedure which necessitated also mathematical operations. These methods, however, make possible the occurrence of various errors, calculating mistakes and mistakes in decimals, which mistakes may be costly and must be avoided, especially in medical X-ray 20 work where such errors may give rise to great danger. Other objects and features of the invention will be more fully understood from the following description to be read in connection with the 5 accompanying drawing in which: 7

Fig. 1 diagrammatically illustrates a conventional slide rule; v

Fig. 2 is a view in elevation of an apparatus embodying the invention; 30 Fig. 3 is a view in elevation of an apparatus embodying the invention in modified form;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3;

Fig.5 is a fragmentary sectional view taken on the line 55 of Fig. 3; and

Fig. 6 is a view inelevation of an apparatus embodying the invention in another modified form.

The system is based on the ordinary slide rule 40 in which, according to Fig'. 1, length B is added to length A. The length C equals the sum of the lengths A and B, and thus, when the scales are logarithmic the product AXB may then be read 01!. v

45 The length B, however, is not independent of the length A, inasmuch as its starting point is determined by the terminal point of line A, and that means that the length B is determined by the value of another factor. Thus, the length 50 B can be adjusted only after A has been determined. In order to'avoid this condition, which occurs in similar manner with nomograms and which makes their use diflicult to less experienced operators, the following changes are made:

55 AccordingtoFlg. Zaribbon l'isflxedly con- In Germany June 29, 1936 nected to and wound around the 'turnable roller D, runs over the roller G and has its end fixed to the roller E. The rollers D and E are rotatably mounted on baseboard II but cannot be shifted, whereas the roller G may be shifted in the direction of the double arrow l2 either upwardly or downwardly, its position depending upon the spring F and upon how much ribbon is wound off from the rollers D and E.

If from the roller D, hearing an indicator I311, the length d is wound off and from the roller E, bearing an indicator Ma, the length e is wound oil, the shifting of the roller G in the direction of the spring equals (d+e)/2; that is, in proportion to the sum (d+e) If new, on the scales I3 and M at D and E, respectivelmlogarithms are put in place of the values it and e, and if the scale l5 at G shows half measure and is logarithmic also, then the indicator l6 associated. with the scale at G- will indicate the product dxe. The advantage of this arrangement lies in the fact that the scales at D and E are fixed and can be simply and independently adjusted and also that the result may be read ofi on a separate scale, which gives the correct position to the decimal point. I

The separation of the two scales lends the possibility of further improving the construction of the invention for cases in which the two factors which are to be adjusted are dependent upon one another as, for instance, in Fig. 2 where the value c is a function of the value d. A calculation of this type might be the determination of the electrical input to an X-ray tube, which is the product of current and voltage, there being a dependcut relationship between current and voltage because the voltage drops with increasing current. A further important example of such a calculation might be the determination of an X-ray dose as a function of the tube voltage and the filter thickness, since the absorbing capacity of the filter is largely dependentupon the voltage.

Thus, if the scale of the dependent factor is adjusted simultaneously with the adjustment of the other factor, problems such as those mentioned can be solved. An apparatus capable of such operation is shown diagrammatically in Fig.

3, which illustrates an arrangement basically similar to that illustrated in Fig.' 2, in that it embraces a first fixed rotatable roller, 9. second fixed 5 rotatable roller, a flexible ribbon connected to and wound about said rollers, and a third roller over which the ribbon passes, the third "roller being urged by a spring or the like so as tb'hold taut the length of the ribbon which is notwound upon the first mentioned rolle'rs,-the third roller being provided with a suitable scale and pointer.

product of both values. The dropplng'ofthe. voltagewith increasing current is taken into account by the fact that when the current indicator is regulated on the current scale the adjustment of this indicator automatically changes the volt-.

age scale. If then, the .voltageindlcator is adjusted to the desired position on the voltage scale which was previously shifted, the result indicator will indicate on its scale the true value of the electrical input, the voltage drop having I been considered.

It more than two factors are to be jointly considered to give a single result, as where X-ray dosage is to be determined from exposure time, voltage, current, distance and filter, then the following form of the invention may be used; according to Fig. 4 a flexible ribbon Z that is fastened at point L lies around shiftable rollers M, N, O, and P. These rollers are held in position by ribbons or rods fixed thereto, their point of rotation being movable by these either upwardly or downwardly. Thereby, the point R is shifted as indicated on scale 8 by a pointer. The shifting of the pointer R on the scale 8 is. proportional to the sum of the shiftings m, n, o, and' p, and if all the scales are correspondingly divided logarithmically, indicates the product of m n o p. I D

Since many changes may be made in the invention without departing from the scope thereof, it is intended that all matter set forth in the above description, or shown in the accompanying drawing, be regarded as illustrative only and not in a limiting sense.

I claim:

1. A calculating apparatus of the character described, including a first adjustably mounted member, first indicator means operatively assoelated with said first adjustable member, a first scale bearing element adapted to cooperate with said first indicator means and being fixedly mounted, a second adjustably mounted member, second indicator means operatively associated with said second adjustable member, a second scale bearing element adapted to cooperate with said second indicator means and being adjustably mounted, an operating arm adjustable with said first adjustable member and adapted to change the position of said second scale bearing element in accordance with changes in the adjustment of said first adjustable member, a third scale hearing element, third indicator means arranged in operative relationship with said third scale bearing element, and means including a flexible ribbon connected to said first adjustable element and to'said second adjustable element for changing the position of one of said last mentioned elements with respect to the other in accordance with changes in the adjustment of at least one of said two first mentioned adjustable members.

2. A calculating apparatus of the character described, including a first adjustably mounted member, first indicator means operatively associated with said first adjustable member, a first scale bearing element adapted to cooperate with element in accordance with changes in the adjustment 'of said first adjustable member, said second adjustable scale bearing member having an extending portion against which said operating arm bears, athird scale bearing element, third indicator means operatively associated with saidv third scale bearing element, and means for changing the position of one of said two last mentioned elements in accordance with changes in the adjustment of said first and second adjustable members.

KURT SIEGFRIED LION.

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