US1791265A - Key mechanism for calculating machines - Google Patents

Description

Feb. 3, 1931. DAME 1,791,265

KEY MECHANISM FOR CALCULATING MACHINES Filed Aug. 12, 1929 2 Sheets-Sheet 1 Fig.1.

BY fid/r /%Qa, y 24m? ATTORNEYS Feb. 3 1931. DAME 1,791,265

KEY MECHANISM FOR CALCULATING MACHINES Filed Aug. 12, 1929 2 Sheets-Sheet 2 INVENTQR B Frederic/1 Dame WM, JM, may

ATTORNEYS Patented Feb. 3. 1931 UNITED STATES PATENT OFFICE FREDERICK DAME, OF DETROIT, MICHIGAN, ASSIGNOR TO BURROUGHS ADDING MA- CHINE COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN KEY MECHANISM FOR'CALCULATING MACHINES Application filed August 12, 1929.

This invention relates to a key mechanism for calculating machines, and it is directed particularly to a mechanism for compelling full strokes of the keys in a keydriven calculator.

In key-driven calculators the calculating mechanism is not only indexed by depression of the amount keys, but certain parts of the mechanism are actuated distances which are .1 proportional to the value of the amount keys with the result that errors will occur.

a second time before it has been fully restored from a prior depression. In such event the calculating mechanism has not been allowed to return to normal and the second depression of the key will not move it through the proper proportional.distance-to secure an accurate registration. It therefore becomes necessary to insure that each key is fully restored from a prior depression before a subsequent depression occurs. Various locking devices have been provided for insuring full depression and full restoration of the keys of a key driven calculator, the present invention being directed to an improved and simplified construction.

The general object of the invention is to provide an improved mechanism for preventing return of a partially depressed calculator key until after the same has been fully depressed.

A further object is to provide an improved locking mechanism thatwill not only compel a full depression of thekey, but will also compel full restoration thereof before a second depression.

Other objects are to provide an improved mechanism of this character that is simple and inexpensive, while at the same time efficient and durable.

Further objects and advantages of the m- Serial No. 385,271.

vention will appear from the following specification.

An embodiment of the invention is shown in the accompanying drawings in which:

Fig. 1 is a sectional side elevation of a calculator with the invention applied thereto;

Fig. 2 is a fragmentary sectional front elevation of one of the keys of the machine illustrated in Fig. 1;

Fig. 3 is a perspective view of one of the locking devices of the invention;

Fig. 4 is a fragmentary sectional side elevation illustrating the locking mechanism in normal position;

Fig. 5 is a view similar to Fig. 4 with the locking mechanism in the position'it occupies when one of the keys has been partially depressed; and

Fig. 6 is a view similar to Fig. 4 showing the parts in the position they occupy when one ofthe keys has been partially restored after having been depressed.

The invention is shown applied to a. Bur- -roughs key-driven calculator, the general features of which are well known as the machine has been on the market for a number of years and is illustrated and described in numerous United States patents, as for example, Horton No. 1,016,501, No. 1,156.600, and 1,243,839. The invention may be fiisod with any other suitable type of calculating machine and since the details of the calculator are incidental to an understanding of the: invention, the construction of the calculator will be described only in a general way.

The machine has a plurality of banks of depressible amount keys numbered from 1 to 9 inclusive in the order of their value. These keys have key stems 10 that are provided with lateral projections 11 (Fig. 2) which, when the keys are depressed, contact a movable bar 12, the keys being urged upward by springs 13; The rear end of bar 12 ispivoteiil at 1 1 to a triangular member 15 that swings about a pivot 16, the member 15 being urged clockwise by a spring 17. The forward end of the bar 12 is pivoted at 18 to-a link 19 having a pin and slot pivotal connection with an indexing bar 20. The indexing bar 20 is provided with indexing stops 21 adapted to obvious that if the result that an error will occur.

engage the key stems and the bar is pivoted at its rearend to the triangular member 15. The indexing bar is pivoted at its forward end at 22 to a toothed sector 23 pivoted at 24 and provided with teeth adapted to mesh with a pinion 25 that, in turn, rotates an indicating dial 26 through a one way pawl and ratchet connection with pinion 25".

When one of the amount keys is depressed, as for example the 5 key, the projection 11 on the key stem swings the bar 12 downward and moves the indexing bar 20 forward; the latter being limited to five steps of movement by the engagement of one of its projections 21 with the 5 key stem. During the forward movement of the indexing bar the clockwise movement of the pinion 25 is an idle one because of the pawl and ratchet connection between it and the pinion 25*, but upon the return movement of the indexing bar under the influence of spring 17 the pawl and ratchet connection causes pinion 25 to advance the'indicating dial 26 five steps, that'is, the same number of ste s as the value of the key depressed. It will he 5 key is not fully depressed the indexin bar will not be moved forward to its full position with the result that, when it is returned under the influence of the spring 17 the dial 26 will not be moved five steps. Likewise, if the 5 key is depressed a second time before it is fully restored, the indexing bar will not have moved back to'its fully restored position to move the dial 26 five steps before the bar will have been moved forward again, with-the It is to prevent these errors that the present invention has been devised.

In order to prevent the depression of more than one key of a given bank at a time, pendants 27 are provided betweenthe keys, thependants being pivoted on shafts 28. The lower ends of the pendants are wide and the wide portions of adjacent pendants are adapted to contact one another under projec tions 29 (Fig. 2) on the key stems. The entire series of pendants for any one key bank is mounted so that thereisroom for only one projection 29 at a time, that is, when one key is depressed and itsprojection 29lpasses between the adjacent pendants, all the other pendants are in contact with one another so that no other key in that bank can *be 'depressed owing to the factthat its projection 29 cannot pass down between the pendants. As long as one key is partly or fully depressed none of the other keys of its bank can be depressed. This construction is known and is described in Horton, No. 1,243,839.

The present invention comprehends an individual locking mechanism for each pair of keys instead of a general locking mechanism for all the keys. Inasmuch as the locking device for each pair of keys is the same, only one will be described, it being understood that the locking devices for the other pairs are the same.

Referring to Figs. 2 and 4, it will be observed that the adjacent faces of a pair of key stems 10 (the 4 and the 5 keys) are serrated at 30, the serrations being relatively small and quite numerous. Notches are provided on the faces of the keys at both the top and the bottom of the series of serrations, there being a set of top notches 31 and corresponding bottom notches 32. Mounted between the key stems on the shaft 28 that carries the pendants is a yoke 33, best illustrated in Fig. 3. This yoke carries a flat spring 34 which is relatively broad where it is attached to the yoke and gradually narrowed toward its ends so that the ends will flex more easily than the body. This spring is of such length that it normallyoccupies the position illustrated in Fig. 4 where its ends project into the respective lower notches 32 in the faces of the key'stems. The spring is slightly shorter than the distance between the bottoms of the notches, but it is longer than the distance between the bottom of one notch and the bottom of the serrations on the opposite key stem.

WVhen one of the keys ofthe pair is depressed, as for example the 4 key, the spring 34 moves endwise slightly until its end engages the bottom of the notch 32 in the 5 key stem after which the opposite end of the spring is flexed downwardly as illustrated in Fig.5. This is caused by the serrations in the stem ofthe 4 key passing over the end of the spring and camming it downwardly. As the 4 key starts to move the first serration swings the spring to the'right causing its opposite end to engage the bottom of the notch in the key stem of the 5 key. The movement of the spring to the right being limited, the depression of the key causes the spring to flex and it snaps over the serration, the position 'of the spring during this movement being illustrated in Fig. 5. If the 4 key should be released while it is only partially depressed, it will be blocked against return because, as it starts to return, one of the serrations engages the end of the spring which tends to move the spring upwardly, but such upward movement is prevented owing to the fact that the spring cannot swing to llo the right and it is bent to a position such that ,it cannot pass upward acrois center owing to the fact that the spring is longer than the distance between the bottom of the notch in the 5 key stem and the bottom of the serrations in the 4 key stem. -The 4 key is thus locked against returning until it is fullv depressed. When it is fully depressed, the end of the spring 34 moves into the upper notch 31 of the 4 key stem.- This allows the spring to straighten out and when the stem of the 4 key returns upward underv the influence of its spring the locking spring 34 is flexed in the opposite direction as illustrated in Fig. 6. This permits the key to restore freely but, should. an attempt be made to depress it, before it is fully restored, one of the serrations engages the endof the spring 34 to prevent such depression, the action being the same as in the case of a partially depressed key.

locking device acts for both keys ofits pairand the two keys cooperate in making the locking device efl'ective.

,While the locking device has been shown .for a-pair of keys, it could be used for only one key as is illustrated, for example, at the left hand end of Fig. 1, where, on account of the fact that an odd number of keys is present in the column, it is necessary to have a locking device for a single key. In this case no serrations are provided on the 2 key, the face of the 2 key merely acting to prevent movement of. the locking spring 34 to the right. Of course, if desired, any other suitable member could be used for preventing movement of the locking spring to the right,

i it merely being necessary to prevent movement of the locking spring so-that it will act on the serrations as illustrated in Figs. 5 and 6. I

It is to be understood that the construction shown is for purposes of illustration only and that variations may be made in it without departing from the spirit and scope of the invention as defined by the appended claims.

I claim: I I 1. In combination. in a calculating machine, a depressible key having a key stem provided with serrations, a flexible member held against endwise movement, the end of said member being adapted to pass over said serrations as the key is moved, said member being mounted so that as the key is depressed said member is flexed in one direction and as the key is restored said member is flexed in the opposite direction whereby return of a partially depressed key and depression of a partially restored key are prevented.

2. In a calculating machine, a depressible key having a keystem provided with serrations, a notch at each end of the series of serration, a flat spring mounted so that its end normally extendsinto one ofsaid notches, and means for preventing endwise movement of the spring.

3. In a calculating machine, a key having a key stem provided with a series of serrations, a notch at each end of the series of serrations, a pivoted arm carrying a flat spring having its end normally positioned in one of said notches, and means for limiting the movement of said arm.

4. In a calculating-machine, a pair of depressible keys, serrated members movable with said keys, a flat, endwise, movable flexible spring mounted between said serrated members and held against endwise movement by one of said members while the other is moved, the end of said spring being flexed in one direction by the serrations of one of said keys when the latter is depressed and flexed in the opposite direction as said key is ,restored after a full depression.

5. In a calculating machine, a pair of depressible keys, serrated members movable with said keys, a notch in each member at each end of the series of serrations, and a flat, endwise movable flexible spring having its ends normally positioned in opposing notches in said members, said spring being slightly shorter thanthe distance between the bottoms of opposing notches but longer than the distance between the bottom of one notch and the bottom of the opposing serrations.

' 6. In combination, in a calculating ma chine, apair of depressible keys, serrated members movable with said keys,'said members having notches at each end of the series -of serrations, a pivoted member carrying a flat spring having its ends normally positioned in opposing notches in said serrated members, said spring being of such length that as one of the keys is moved the spring is swung to cause one of its ends to engage the bottom of the notch in the serrated mem ber of the unmoved key, the other end of said spring being flexed in the direction of movement of the moved key by the serrations moved by said key for the purpose described.

7L In a calculating machine, a pair of de pressible keys having key stems provided with serrations, notches at the upper and at the lower ends of the series of serrations in each key stem,a pivoted yoke between said key stems, and a flat spring carried by said yoke, the ends of said spring normally occupying the opposed lower notches in said key stems,

said spring being slightly shorter than the distance between the bottoms of opposing notches but longer than the distance between the bottom of one notch and the bottom of op osed serrations.

n testimony whereof, I have subscribed

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