US2531881A - Apparatus for control of typewriters - Google Patents

Description

Nov. 28, 1950 c. T. JACKSON APPARATUS FOR CONTROL OF TYPEWRITERS Filed Oct. 10, 1946 INVENTOR m 1K m J T n m. H w

ATTORNEY Patented Nov. 28, 1950 APPARATUS FOR CONTROL OF TYPEWRITERS Carlton '1. Jackson, Conesus, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application October 10,1946, Serial No. 702,521

12 Claims.

This invention relates to typewriting machines, and more particularly to contact mechanism suitable for use in or with typewriting machines which may be wholly or partly electrically controlled.

An object is to provide an improved selective contact operating mechanism suitable for use in or'for controlling power-operated typewriters and other keyboard machines or for remote control of such machines.

An object is to provide a key controlled power operated contact device.

An object is to provide a contact operating mechanism which is more precise and uniform in timing the contacts.

' Another object is to provide a contact operating mechanism which enables very short periods of closure or opening of the contacts to be obtained.

An object is to provide a contact operating mechanism in which the duration of closure or opening of the contacts may be readily varied.

"An object is to improve contact mechanisms of the type disclosed in Patent 1,996,013.

In the past it has been customary to provide certain types of keyboard machines, such as power operated typewriters and the like with contact mechanisms for the purpose of controlling electrical devices or circuits selectively, for example, to control another machine remotely or to control the impulse distributor of a printing telegraph system. Such contact mechanisms often take the form shown in the above patent in which a power operated device actuates contacts to close or open them, according to the requirements of the problems to be met.

- One of the disadvantages of the method of operating contacts as disclosed in the above patent is that the contacts are operated only on the forward stroke of the power operating device and are kept in operated condition until the power operating device has been restored to the point where the contacts were initially operated. As a result, the duration of the contacts is necessarily rather long and constitutes an appreciable percentage of the period of the cycle of the power operating device because of the difliculty of adjusting the contacts precisely enough to permit a shorter duration. Such a contact mechanism often is unsuitable because there are times when the circuit controlled by the contacts must be made and broken, for example, before the mechanism operated by the power device is fully operated. An illustration is where a series of contact closures must be made during the course of operation' of a mechanism by a power device and the periods of closure must not overlap. It is not possible to use contact operating mechanisms like the one disclosed in the patent for this purpose because the duration of closure is maintained during a part of the restoring stroke of the power device in consequence of the method of actuating the contactsby means of a part connected to the power device which directly engages the contacts when the power device has advanced a certain distance in its cycle.

The present invention aims to supply the foregoing lack by providing a contact operating de-- vice which makes it possible to operate the contacts completely before the power operating device has completed its forward stroke and which will not operate the contacts while the power device is restoring. Alternatively, the mechanisms described hereinafter makes it possible to secure the opposite result of operating the contacts during the restoring part of the cycle of operation of the power device.

Another object is to provide for changing the duration of the contact closure by a simplechange in the size of the principal member which operates the contacts.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of theinvention and the best mode, which has been contemplated, of applyin that principle.

In the drawings: Fig. 1 is a vertical section showing power operating device for a typewriting machine with board controlled machine, for example, a power operated typewriter, in which the instrumentalities of the machine, such as the type bars and:

other devices, are actuated by cam units like Ill of well known construction which cam units cooperate with the usual power ggoller i I The cam units H) are of the same type disclosed in Patent No. 1,996,013. When the key 52 controlling the cam unit I0 is depressed an extension- I 2a thereon'cooperating with the detent lever I 0a of the cam unit releases the cam Illb of the cam.

unit and allows a spring, not shown, to rotate the cam it?) slightly in a clockwise direction. This enables the power roller H to actuate the cam unit in a counterclockwise direction about the pivot wire 13, thereby drawing down the link Illa connected to the type bar or other device.

It is desirable in the application of many keyboard controlled machines, such as power operated typewriters, to close circuits selectively under control of the keys on the keyboard, as in many of the applications of such machines some of the mechanisms are electrically operated and the control circuits therefore must be established by the keys. A specific example is the remote control of one typewriter by another typewriter, the first typewriter often closing circuits which control a transmission circuit of some kind to cause the second typewriter to function.

In the past the cam units Ill have been provided with extensions Iflc which directly actuate contacts, like the contacts C (Fig. 1) carried by members 15, by the engagement of a part of the extension, such as a pin, with a movable contact member l5 which thereby is directly moved by the extension to close contacts C. One of the drawbacks of such mechanisms is that the point of closure and duration of the contacts C is somewhat uncertain. In the drawings there is shown a means of operating the contacts C which has been found to be more certain and which, within certain limits permits the duration of the contacts to be readily controlled.

Instead of operating the upper contact member i5 of the contacts C directly, as by means of an insulating pin or similar device on the extension lqc, there is provided a triangular contact operating element 14 which preferably is made of an insulating material and is freely rotatably mounted on a pin llld carried by the extension lilo. The top member l5 for the contacts C may be bent at an angle at the point A and also is provided with a stop plate B.

Normally one of the points of the triangular element 14 abuts the left hand edge of the plate B with the bent portion A on the contact member 15, lifting the lower right hand point of the contact operating element [4 slightly. A clearance is provided between the point of member l4 nearest the plate to insure that the parts assume the position shown in Fig. 1.

When the cam unit I is rocked in a counterclockwise direction as described above, the lower right hand point of the element l4 engages the edge of plate B and, due to the fact that the pin id is above the level of plate B, the element M will be rotated. The extension Illc and element I act like a toggle to depress the upper member 15 of contacts C and close said contacts, as illustrated in Fig. 2, the parts being shown in approximately a dead center position in this figure.

With a little additional movement of the extension I0c in a counterclockwise direction, the spring pressure of the upper contact member I5 on the element l4 causes rotation of the element M to the position of Fig. 3, thus permitting the contacts to reopen. The extension Inc may continue to the right (Fig. 3) on plate B as far as desired but the contacts 0 will remain unaffected. On the return stroke of the extension Illc, the element l4 travels to the left and at first merely slides over the surface of the plate B but eventually the lower left hand point of element M in Fig. 3 will engage the bent portion A and at about the same time the lower right hand point will slide off the plate B and the parts will reassume the position of Fig. 1.

The mechanism just described enables the contacts C to be operated on the forward or counterclockwise stroke of the cam unit l0 while it is operating the type bar or other instrumentality. With this mechanism the contacts C may be normally open or normally closed or both, as desired, the drawings showing normally open contacts.

It will be understood, in the case of normally closed contacts, that the plate B and the bent portion A may be placed on the lower contact member E5, in which case the contacts C will be opened when the cam unit in rocks counterclockwise.

There may be cases where it is desired that the contacts be operated after the device operated by the cam unit 10 has been operated. In other words, it may be desired, for example, to close the contacts C on the return stroke of the extension lBc. For this purpose the mechanism may be arranged as shown in Fig. 4 in which the positions of the plate B and the bent portion A are reversed and the element I4 normally occupies the same position in Fig. 4 as it takes in Fig. 3.

When the extension lllc in Fig. 4 moves counterclockwise to the broken line position (Fig. 4) it will be seen that the contacts C will not be operated and will remain open, the upper contact member 15 merely springing upwardly slightly when the element 14 passes out of contact with the plate B and takes the position shown in the broken lines. On the return stroke of the cam unit E0, in which the extension I00 moves to the left in Fig. 4, the lower left hand point of element [4 will engage the plate B and operate the contact C in exactly the same manner as described above, causing said contacts to be closed by the toggle action occurring between the element It and the extension I80, the contacts C reopening when the member I4 passes the dead center position sufficiently to enable the r spring tension in the upper contact member IE to rotate the element M back to approximately the position of Fig. 4.

By increasing the size of the element M or decreasing its size, as the case may be, the duration of closure of the contacts C may be increased or decreased at will. It is apparent that the shorter the sides of the triangular element M the shorter the amount of time it will take to cause rotation of the member M the one-third of a revolution necessary to eifect one full operation of the contacts 0. Another advantage of the mechanism is that the points of closure may be more precisely controlled than is the case with conventional mechanisms in which a stud carried by the extension engages the contact member 15 directly. In such mechanisms usually one of the spring contact members i5 is bent to form an inclined cam surface against which the pin on the extension bears to actuate the contacts. Such elements are very indefinite in their timing, due to the fact that the resilient spring member becomes gradually bent out of position with the result that the time is liable to vary progressively and it is very difiicult to adjust such contacts to a precise timing. It is also particularly difficult to adjust such contacts for duration because so much dependence has to be placed upon the rigidity of the spring contact member l5 and upon precise bending of the spring member to get the necessary 5 adjustment. With the mechanism disclosed in the drawing the adjustment of the spring members I5 is not critical.

The drawings show the element M as triangiilar in shape and the contact member cooperating therewith as having the bent portion A. Neither of these structural characteristics of the illustrative embodiment of the invention is essential. Where the triangular-element is used the pin Hid will necessarily be located at the intersection of the bisectors of the angles of the triangle. This brings the pin [d very close to the upper contact member l5, thereby making the force required to overturn the element I4 relatively large in comparison with the force required with an element in the form of a square, the sides of which are the same in length as the triangular element. In order to reduce this overturning in force, in other words, to make the triangular element l4 overturn more easily, the bent portion A is provided to raise the pin llld slightly in relation to the contact member. However, it has been found that, even without the extension A, the mechanism operates successfully, although more force is required to overturn the element [4. By making the element M in the form of a square, the sides of which are the same length as the sides of element M in the drawings, the pin Hid will be spaced away from the contact member with which it cooperates the distance of one-half the length of a side which is considerably greater than the spacing shown in Fig. 1. This makes the element l4 much easier to overturn and in cases where there is a heavy burden on the cam unit to operate the desired mechanism, and the contacts C at the same time, the square form of element lfld may prove very desirable.

By positioning the plate B at various points along the upper contact member i5 in Figs. 1 and 4 the point at which the contacts 0 are operated may be varied. For example, in Fig. 1 the plate 14 might be shifted further to the right or shortened so that the contacts C will be operated nearer the end of the stroke of the cam unit I0. Similarly, in Fig. 4 the plate B may be shortened or shifted to the right so that the contacts C are closed only when the cam unit It is fully restored.

It is quite apparent from the foregoing that r the point of operation and duration of contact of the contacts may be controlled over a wide range and be made very precise, particularly in the case of normally closed contacts which it is desired to open at a very precise point in the operation of the cam unit. In the timing of electrically controlled devices, sometimes the closing time is not particularly important but the point at which the contacts are opened may be very critical. In the case of the mechanism disclosed above, 0W- ing to the snap action which occurs at the point where element 14 overturns, it is possible to get a very precise reopening or reclosure of the contacts C, particularly if the triangular element I4 is made as small as possible to reduce the overturning time to a very small value. In the arrangement shown in the drawings, the closing time may not be very precise and may vary somewhat, due to wear at the vertices of the triangular element but, owing to the snap action occurring when the element I4 is overturned, the reopening of the contacts will be very precise and quick. It is thus apparent that a relatively large amount of control over the precision of operation of contacts C, both in point of time and duration, may

be obtained by varying the size of the element N, the number of sides which it may have and the relative positions of the plate B.

While there have been shown and described and pointed out the fundamental novel features of the invention, as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

l. A key-controlled power-operated switching device for typewriting and other ofiice machines comprising contact means including a contact operating element having a guiding surface and an abutment, a key controlled power operated device having an oscillatable member, and a polygonal contact actuating element mounted for rotation on said member and having one polygonal side engaging said surface, said element, when said member is oscillated, engaging said abutment and having rotation imparted in consequence of motion of said member while said element engages said abutment, said rotation'actuating the contact means.

2. A contact mechanism comprising a contact actuating blade having an abutment, a power device including an element having a to-and-fro motion, and a polygonal contact actuating member rotatably mounted on said element and having its corners engageable with said abutment and rotating in consequence of such engagement to actuate said contact blade.

3. A contact mechanism comprising a contact operating device having a to-and-fro motion, a polygonal contact actuating element rotatable on said device, contact means, and a contact member engageable by said element during a part of the motion of said device and having a portion shaped to act as a fulcrum for any one of the vertices of the polygonal element and cause rotation of the latter by engagement with a vertex of the polygonal element, said rotation displacing said member sufficiently to operate the contact means.

4. In a contact mechanism, an invariably 0perated member having a fixed operating cycle between two limits of motion, a contact member, and a rotatable element carried by said operated member and having a series of contact operating projections engageable one-at-a-time with said contact member at a definite fulcrum point between said limits of motion so as to be partly rotated in consequence of such engagement to thereby operate said contact member.

5. A contact mechanism comprising a vibratory actuating member, a star wheel rotatable on said member, and a contact member shaped to pivotally engage one of the points of the star wheel with each vibration of the actuating member and cause the star wheel to rotate and thereby operate the contact member.

6. A circuit controlling mechanism comprising an oscillatable actuating device, a rotary member on said device having a series of radiating projections, and a contact member movable betwen circuit opening and circuit closing positions and having a stop portion pivotally engaging one of said projections during each oscillation of said device to cause rotation of said rotary member and at the same time being displaced by said rotation from one of said positions to the other.

7. A key-controlled power-operated switching mechanism for typewriters and other office machines comprising a key-controlled power operated device having an oscillatable member, a switch including a switch actuating member, and a star wheel rotatable on said oscillatable member, one of the points of said star wheel being pivotally engageable with the switch actuating member at a definite point in the cycle of the oscillatable member to cause rotation of the star wheel and thereby operate the switch through said actuating member.

8. A contact mechanism comprising a contact actuating blade having a Stop portion, a power device including an element having a fixed travel between two limits of operation, and a star wheel rotatably mounted on said element, one of the points of said star wheel pivotally engaging said stop portion during the travel of said element to cause rotation of the star wheel and thereby effect an operation of the contact actuating blade.

9. In a contact actuating mechanism, a contact Operating device including an element having a travel between two extremes of movement, a contact controlling member rotatably mounted on said element and comprising a symmetrical multi-lobed Wheel, and switching means including a member adapted to be displaced by pivotal engagement of a predetermined portion of the second member with one of said lobes and subsequent rotation of the controlling member.

10. A contact mechanism comprising a con tact actuating device having an invariable excursion between two limits, a multi-pointed element pivotally mounted on said device, and a contact controlling member having a fulcrum portion engageable by one of the points of said element at a predetermined position in the excursion of said device and effecting rotation of said element, said member being displaced by said rotation.

11. a power-operated typewriter or like machine, power operating mechanism including a power roller and a cam unit oscillatable by said roller, a toothed member rotatable on said unit and movable therewith in an arc of a circle, and a contact controlling member positioned to be engaged by one of the teeth of the toothed memher during an oscillation of the cam unit by the power roller and displaced thereby, said member rotating said toothed member suificiently to place another tooth in position to operate said member the next time the cam unit is oscillated by the power roller.

12. A contact mechanism comprising contact means, a member for actuating the contact means, a member movable back-and-forth between two limits of motion; and an element pivotally connected to the second member and having a series of projections successively pivotally engageable one at a time with a fixed part of the first member, said element, in consequence of said engagement, being rotated to bring another projection into position for the next operation and at the same time to operate said contact actuating member.

CARLTON T. JACKSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 13,081 Miller Feb. 8, 1910 1,839,916 Ehrlich Jan. 5, 1932 1,862,006 Collins June 7, 1932 1,996,013 Thompson Mar. 26, 1935 FOREIGN PATENTS Number Country Date 108,802 Switzerland Apr. 4, 1923 665,793 France May 13, 1929

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