US2945577A - Keyboard lock mechanism - Google Patents

Description

July 19, 1960 L. P. FRECHETTE, JR 2,945,577

KEYBOARD LOCK MECHANISM Filed Feb. 25, 1959 r 2 Sheets-Sheet l INVENTOR LEO e Faacusggur. BY M ATTOR EYS July 19, 1960 P. FRECHETTE, JR 2,945,577

KEYBOARD LOCK MECHANISM 2 Sheets-Sheet 2 Filed Feb. 25, 1959 INVENTOR LEO I? FRECHETT Fig.4

M K! ATTORNYS United States Patent KEYBOARD LOCK MECHANISM Filed Feb. 25, 1959, Ser. No. 795,445

4 Claims. (Cl. 197-17) This invention relates to mechanism for locking and unlocking the keyboard of electric typewriters; more particularly it relates to mechanism adapted to elfect unlocking of the keyboard of an electric typewriter only if electric power is available; and specifically it relates to mechanism under the control of the typewriter on-off key and operable in combination with the electrically driven motive source of the typewriter to efiect unlocking of the keyboard of an electric typewriter.

Electric typewriters presently in vogue include an electrically powered operating means for driving the various machine instrumentalities, such as type bars, carriage return mechanism, and so forth. The operating means is continuously driven when the typewriter is con ditioned for operation upon actuation of an on-ofi key. The actuation of the typewriter instrumentalities is effected by key controlled engagement of an actuator with the continuously driven operating means such as a rubber roll or toothed snatch roll. If an actuator is released by key operation after loss of electric power, the released actuator will remain in engagement with the now quiescent operating means so that upon restoration of power, the released actuator and associated instrumentalities will be operated. As is apparent the simultaneous operation of several actuators can be injurious to the machine.

The above problem has been alleviated somewhat in the provision of electromagnetic means controlled by power being delivered to the electrically powered operating means and responsive to power failure for returning the on-oif key to the off position and for locking the typewriter keyboard. In the machines incorporating such electromagnetic means, the keyboard is unlocked when the on-oif key is placed in the on position.. Movementof the on-off key to on also effects the closure of a switch. If power is available, it is supplied through the switch to the operating means and to the electromagnetic means, the latter maintaining the on-ofi key in the on position and the switch closed. Should the on-off key be placed in the on position in the absence of power, the keyboard will be unlocked and remain unlocked for as long as the on-ofi key is held in the fon position.

While the on'otf key is held in the on position in the absence of power, keys may be depressed and their associated actuators released into the quiescent operating means. The result is that when power is restored and the typewriter is conditioned for operation the same aforementioned undesirable operation of the actuators released during power failure will occur.

stance by means of a spring 20.

2,945,577 Patented July 19, 1960 ice In brief this invention completely overcomes the above described problem in the provision of mechanism which is conditioned by movement of the on-off key to the on" position to effect the unlocking of the typewriter keyboard by the electrically powered operating means. If power is not available the keyboard can not be unlocked when the on-ofi key is moved to and/or held in the on position.

The principal object of the invention is to provide power operated mechanism for unlocking the keyboard of a typewriter when it is conditioned for operation.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by references to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

Figure 1 is a partial cross sectional view of a,typewriter showing the association of parts comprising the instant invention in normal inoperative position with the machine oil.

Figure 2 is a view of the power circuit connections Figure 3 is a view similar to Fig. 1 showing the parts in intermediate positions after the on-ofi key of the main operative position and the keyboard unlocked after machine has been turned on and power was availa e.

Referring now to the drawings wherein is shown a preferred embodiment of the invention incorporated in an electric typwriter having a construction similar to the known construction of Royal electric typewriters, and wherein like or corresponding parts throughout the several views are designated by the same reference numeral, there is shown in Fig. 1' an on-ofi key 10 which is fulcrumed on the machine frame 11. A link 12 is connected between the on-oif key and a lever 14 which is fulcrumed at 15 whereby when the on-ofi key is moved from the o position shown, to the on" position shown in Figs. 3 and 4, lever 14 will rotate counterclockwise about its fulcrum.

As more fully described in Patent No. 2,810,466 rotation of the lever 14 is adapted to close switch contacts 16 whereby electric power on terminals 17 (Fig. 2) is connected to a capacitor motor 18 and to the coil of an electromagnet 19. Energization of the motor 1% drives the typewriter power roll as is understood, and energization of the electromagnet 19 maintains the onoff key 10, through levers 14 and 12, in the on position and switch contacts 16 closed. Manual movement of the on-ofi key to the off position or a power failure will cause switch contacts 16 to open, in the latter in- In addition and in accordance with the present invention lever 14 is adapted through movement of an outwardly, forwardly, and inwardly extending stop member 21 formed thereon between fulcrum 15 and lever 12, to condition the keyboard lock mechanism as will hereinafter be explained whereby if and only if power is available the keyboard will be unlocked.

Operation of typewriter instrumentalities (not shown) are effected by depression of keys 22. Each key lever is provided with a projection 23. The projections depending from all of the keys are substantially aligned across the machine and are adapted to overlie a key locking blade 24 equipped with a shaft 25 mounted on the frame for pivotal movement under or out from beneath the key projections.

The locking blade 24 is adapted to be pulled out from beneath projections 23 by a spring 26 suitably anchored to the machine frame as at 27 (Fig. 3). A stop 28 is provided to limit the clockwise movement of the blade 24. The blade 24 is maintained beneath the projections 23 by a lever 29 fulcrumed at 31. The lever is provided with a bent ofi tab 32 adapted to engage and cam the key locking blade 24 counterclockwise, as viewed in the drawing, about its shaft 25 against the force of spring 26 through an extension 33 of the blade 24. The lever 29 is biased in a counterclockwise direction whereby its tab portion 32 is maintained in engagement with the extension 33 by a spring 34 secured to the lever and to an anchor 35, the counterclockwise movement thereof being limited by a stop 36.

Mounted for rotation with the power roll shaft 37 is a toothed wheel 38 adapted to be continuously driven in a clockwise direction, as viewed in the figures, when the typewriter motor is energized. A wheel 41 rotatably mounted on a shaft 42 is provided with teeth 43 around approximately 240 of its periphery which teeth are adapted to engage the teeth of wheel 38 whereby wheel 41 will be driven counterclockwise over a 240 are by the continuously driven wheel 38. An arcuate peripheral section of approximately 120 between the terminal teeth 44 and 45 on the periphery of wheel 41 is cut away so as to form radially extending lugs 46 and 47. Lug 46 which is shorter than lug 47, is formed with an outwardly extending car 48 adapted to engage the inwardly extending car 49 on stop member 21 when the latter is in its normal inoperative position as seen in Figure 1. Lug 47 is formed with an outwardly extending ear 50 which is also adapted to engage car 49 on stop member 21 when the latter is in its normal operative position as seen in Figure 4. Integral with and extending forwardly from ear 50 and generally following the periphery of wheel 41 is a camming member 51 adapted to cam lever 29 clockwise against the force of spring 34 whereby the tab portion 32 of the latter will be moved out of the path of the blade extension 33.

An arm 52 is rotatably mounted on a stud 53 eccentrically mounted on wheel 41. A spring 54 is secured between the other end of arm 53 and the fixed anchor 35 and tends to bias the arm forwardly and the wheel 41 in a counterclockwise direction so that the ear 48 on lug 46 will abut the stop 49 as seen in Figure 1.

In operation, movement of on-ofi. key to the on position pulls link 12 and rotates lever 14 counterclockwise about pivot thereby moving stop 49 on member 21 thereof up and out of the path of ear 48. This permits the spring 54 to pull arm 52 which rotates the wheel 41 to the position shown in Figure 3. Rotation of lever 14 about its fulcrum 15 also causes switch contacts 16 to close. 'If, however, no power is available wheel 38 will remain stationary and since lever 29 will not be moved the keyboard will remain locked. Upon release of the on-off key, since no power is available, the spring will return the on-off key to the off position but wheel 41 and associated parts will remain in the positions shown in Figure 3. As is apparent even if the key 10 is held in the on position in the absence of power, the keyboard will remain locked.

As is apparent the position of wheel 41 and associated parts shown in Figure 3 could be normal inoperative position with the key 10 in the ofF position thereby eliminating the necessity for lug 46. Lug 46, however, is employed in a preferred construction so as to enable, in

normal and proper usage, wheel 38 to start rotating before the teeth of wheel 41 are moved into engagement therewith whereby smoother operation is obtained.

It is to be noted in Figure 3 that the centers of the shaft 42, stud 53, and spring anchor 35 are not aligned so that spring 54 still exerts pull on arm 52 whereby the wheels are maintained securely in mesh.

If power is available when the on-off key is moved to the ou" position, closure of contacts 16 will cause the energization of motor 18 and solenoid 19 whereby the armature 55 of the latter will hold contacts 16 closed and lever 14 in actuated position thereby holding key 10 in the on" position. Energization of motor 18 rotates wheel 38 which in turn drives wheel 41 now in mesh therewith through a 240 are at which time the spring 54 takes over and rotates wheel 41 to the position shown in Figure 4 with the ear 50 on lug 47 engaging the stop 49 on member 21 to limit rotation thereof. During the latter rotation camming member 51 engages the end 56 of lever 29, moving it clockwise to, and holding it in, the position shown in Figure 4 thereby allowing spring 26 to move the blade from beneath projections 23 whereby the keyboard is unlocked. As long as the key 10 remains in the "on position the position of parts shown in Figure 4 will obtain.

Movement of the on-off key 10 to ofF position either manually or due to power failure will remove the stop 49 on member 21 down and out of the path of car 50 whereby spring 54 will rotate the wheel 41 until stop car 48 on lug 46 engages the stop 49 as shown in Figure 1 or if lug 46 is not employed spring 54 will rotate the wheel to the position shown in Figure 3.

It should be understood that the foregoing disclosure relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

The invention claimed is:

1. In a typewriter or like machine having a keyboard, a keyboard locking blade, means normally biasing said blade into keyboard locking position, electrically powered typewriter operating means, mechanism comprising a rotatable member engageable with siad electrically powered typewriter operating means, manually operable means for simultaneously initiating the operation of and for permitting the engagement of said rotatable member with said typewriter operating means, whereby if electric power is available said rotatable member will be driven by said operating means through a predetermined arc, and a camming element on said rotatable member adapted at the end of the arcuate travel of said rotatable member to engage and actuate said blade biasing means whereby the keyboard will be unlocked.

2. In a typewriter or like machine having a keyboard, a keyboard locking blade, means normally biasing said blade into keyboard locking position, electrically powered typewriter operating means, mechanism comprising a rotatable member in engagement with said electrically powered typewriter operating means, manually operable means for initiating the operation of said typewriter op erating means, whereby if electric power is available said rotatable member will be driven by said operating means through a predetermined arc, and a camming element on said rotatable member adapted at the end of the arcuate travel of said rotatable member to engage and actuate said blade biasing means whereby the keyboard will be unlocked.

3. In a typewriter or like machine having a keyboard, a keyboard locking blade, means normally biasing said blade into keyboard locking position, electrically powered typewriter operating means, means for initiating the operation of said typewriter operating means when moved to a first position, means for maintaining the operation of said typewriter operating means and for maintaining said operation initiating means in said first position if power is available, rotatable means in engagement with said typewriter operating means, stop means, one on said rotatable member and another on said operation initiating means, said stop means being adapted to limit the rotation of said rotatable means to a predetermined arc, and a camming element on said rotatable member adapted at the end of the arcuate travel of said rotatable member to engage and actuate said blade biasing means whereby the keyboard is unlocked.

4. Apparatus as recited in claim 3 wherein said stop means are rendered inefiective upon movement of said operating initiating means to a second position, and means for returning said rotatable member to its initial positlOll.

References Cited in the file of this patent UNITED STATES PATENTS

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