US2233758A - Margin indicator for typewriters - Google Patents

Description

March 4, J A VARNEY ETAL A MARGIN INDICATOR FOR TYPEWRITERS Filed Feb. 4, 1959 37 60 6/ 47 `55 i HARR/J MECH F TERaf/ARR/ que TM5 nel" TTOLVEYS Patented Mar. 4, 1941 UNITED STATES PATENT OFFICE MARGIN INDICATOR FOR TYPE-WRITERS Application February 4, 1939,1Serial No. 254,698

7 Claims.

Our invention relates to typewriters and the like, with special reference to margin indicators, and is directed specifically to means for indicating the bottom margin of a sheet in a typewriter.

In'usual typing practice the operator has the responsibility of guarding against typing too many lines on a page. This responsibility is a troublesome mental burden because the typist tends to be engrossed in the task of transcription and also because, with the end of the page concealed behind the typewriter platen, the approach of the typing to the bottom of a page is not readily apparent. It is common practice for the typist to cease typing long enough to hold a page against the sheet in the machine for guidance in estimating the length of the sheet that is concealed by the platen. There is need, therefore, for some indicating or warning means to relieve .a typist of this responsibility.

We are aware that various devices have heretofore been suggested for this purpose, but none without defects and disadvantages that militate against commercial acceptance.

One object of our invention is to provide a simple, inexpensive, but rugged indicating means for this purpose that may be sold as a readily adaptable accessory, if desired and that will without adjustment or manipulation indicate the bottom margin for either a letter size or legal size sheet of paper.

Our device, like most previous devices, is operated by the rotary platen of the typewriter, the device being synchronized therewith to actuate a signal when the platen has moved a sheet to a point that leaves the desired margin below the typing Since multiple revolutlo-ns of the platen occur between the beginning of a page and the signal point, gear mechanism for interconnecting the platen and signal is necessary. It is also necessary to synchronize the gear mechanism with the sheet. In other words, two relations are involved, the disposition of the signal-actuating mechanism relative to the platen and the relation of the sheet in the machine to the platen, so that it is necessary for the signal or signal-actuating mechanism to be at a predetermined disposition when the sheet in the machine has a predetermined position relative to the platen if the signal is to operate at the proper time.

To permit synchronism in the mechanism when typing a sheet, some prior art devices provide for unmeshing and remeshing of gears that interconnect the platen and signal; but it has been found that remeshing is not always possible at the precise relationship desired, the result being that margins of successive sheets may vary considerably, the tendency to vary being augmented by the gear ratios involved. One of the objects of our invention is to avoid this difficulty by incorporating in the mechanism a friction clutch a combination is that the typist may cause the' signal mechanism to become synchronized with a sheet in the machine by a simple manual movement to release the clutch temporarily when a sheet has a predetermined disposition relative to the rotary platen.

Other objects and advantages of our invention will be apparent in the course of ensuing detailed description, taken with the accompanying drawing.

In the drawing:

Fig. 1 is a front elevation of our device and a portion of a typewriter upon which it is installed, the casing of the device being partly broken away to reveal the interior arrangement;

Fig. 2 is a side elevation of the device taken as indicated by the arrow' 2 in Fig. 1, a portion of the casing wall being broken ,away to reveal the interior mechanism;

Fig. 3 is a vertical section of the device taken along the broken line 3 3 of Fig. 2, and

Fig, 4 isa detail in cross-section to suggest a modication of the invention.

To illustrate the principles involved, we shall direct our disclosure to a device mounted as an accessory on a typewriter, but it will be understood that such an embodiment of the invention is by Way of illustration only, since the invention is applicable to other devices than typewriters and since the invention may be incorporated in the factory construction of a machine instead of being sold as an accesso-ry to be ,added to machines already in service.

The parts shown in Fig. l of a typewriter to which our device is adapted are a vertical frame member I0, a rotary platen II, a platen shaft I2 with a reduced threaded end I3 extending through the frame member, and the usual knob I4 for manually rotating the platen. The knob I4 has an inwardly directed hub- I5 that in the original construction of the typewriter is threaded onto the reduced shaft end I3 and secured thereon by a small set-screw I6.

Our invention includes a shaft extension member, generally designated I9, having an enlarged end 2U adapted to be threaded onto the reduced end I3 of the platen shaft and to be secured thereon by .a set-screw 2l, the opposite end 22 of the shaft extension member being reduced in diameter and threaded to receive the hub I5 of the knob I4. A casing generally designated 23, for housing the mechanism of the device has an aperture 24 in one of its side walls that embraces a portion 25 of the shaft extension member I9 of intermediate diameter and has in its opposite side a second aperture 26 loosely embracing the reduced end portion 22 of the shaft extension member. The casing is conned between an annular shoulder 21 of the shaft extension member and the inner face of the hub I5. To keep the casing 23 from rotating about the shaft extension member I9 on,which it is mounted, .any convenient auxiliary support may be provided, for example, an arm or bracket 30 secured by a suitable screw 3I to the frame member I0 or to any other suitable part of the typewriter.

In the particular construction shown, the casing 23 is made in two separable sections 32 and 33 releasably held together by a pair of assembly screws 34, the section 32 having the character of a lid. For providing positive engagement of the two casing sections with each other, we may mount a small block 35 on the inner face of the section 32 to rest against the wall of the section 33 and may provide' a marginal recess 36 in the section 32 to receive a complementary tongue 31 extending from the section 33. While any type of signal may be employed within the scope of our invention, we prefer to use an audible signal means within the casing and therefore provide a plurality of perforations 38 in one wall of the casing 23 to facilitate the transmission of sound from the interior of the casing.

Within the casing 23, unitary with the shaft extension member I9, is a pinion 40 which, by virtue of the arrangement heretofore described, rotates with the typewriter platen II. Fixedly mounted by one end on a side wall 4I of the casing 23 is a stationary shaft or spindle 42, the outer end of which extends into a complementary aperture 43 in thercaslng section 32. A gear 45 that is both rotatably and slidably mounted upon the spindle 42 is in continuous mesh with the pinion 40 and preferably is sulciently larger than the pinion 40 to make less than one complete rotation within the range of rotation on the part of the pinion 40 that correspondsto the length of a legal size sheet of paper when Vthe sheet is moved through the typewriter in the course of typing.

The movements of the gear 45 longitudinally of the spindle 42 are limited by the fact that the gear has a hub portion 46 that is stopped by the wall 4I of the casing and by the fact that on the other side of the gear is a clutch disc 41 in the path of axial movement of the gear, such arrangement restricting the sliding action of the gear on the spindle 42 to the longitudinal extent of the pinion 40. A suitable helical spring 48, acting between the gear 45 and the clutch disc 41, tends to move the gear axially away from the clutch disc, but normally such movement is prevented by a leaf spring 49 that is disposed to press the gear against the clutch disc. The leaf spring 49 is mounted on the wall 4I of the casing by a suitable screw 50 at its inner end and has Van aperture 5I to clear the hub 46 of the gear 45. It is contemplated that the leaf spring 49 will be subject to manual release by the operator of the typewriter and any suitable means may be provided for this purpose. In the preferred form of our invention, we extend the outer end of the leaf spring through a suitable aperture 52 in the casing 23 to form a protruding handle 53 that may be shifted to move the leaf spring to the right, as viewed in Figs. 1 and 3, to permit the spring 48 to slide the gear 45 away from the clutch disc 41.

The clutch disc 41 which is also rotatably mounted on the spindle 42 is adapted for eiective frictional contact with the gear 45, for example, being provided with a ring-shaped facing 55 of cork, rubber, or other material positioned for contact with the face of the gear45.

One of the features of our invention is the provision of means to urge the clutch disc 41 toward a predetermined initial position correspondlng to a given disposition of a sheet of paper in the typewriter, whereby the signal mechanism may be readily synchronized, with the sheet of paper. Such means may take the lform of a. torsional spring 55 having one endv 51 connected to the clutch disc` andits other end connected to a pin 58 at thel endof thev spindle 42, the spring embracing a` s leeveriil en the spindle 42 adjacent the clutch disc. Normal rotation of the pinion 40 as the lplaten i irotates in the progressive typing of a sheet-,ef paper in the machine causes the gear 45'to'rotate-.ina f Y clockwise direction, as viewed inFig.. 2, and if the ,gear 45 is pressed against the facing 55 of. l 25 49, the clutch disc will correspondingly rotate j Y the clutch disc by the action of the leaf'fsp'rlng' in a clockwise direction. Wheneverthehandlef' 53 is manipulated to release the pressureof the A.

leaf spring 49 on the gear 45, the helical spring 48 shifts the gear 45 out of frictional engage;. ment with the clutch disc 41, whereupon the torsional spring 56 is free to rotate the clutch disc 41 in a counter-clockwise direction to the desired initial position of the clutch disc.v The initial disposition of the clutch disc 41 may be determined by a member 60 unitary with the clutch disc and a stop means in the form of a block 6I mounted on the lower wall 62 of the casing 23. The member 60 may be in the form of va small block or plate inset extending radially from the periphery of the clutch disc 41, the block 6I being in the path of its movement.

The signal means in the present illustrative embodiment is preferably a bell 65 mounted on a post 66 and is operated in response to rotation of the clutch disc 41 by any suitable means. For

example, we may employ a resilient arm 61 mounted on the casing vby a suitable screw 68 and carrying a clapper 69 for the bell 65, and may provide means extending from the clutch disc 41 to engage and actuate the resilient arm for the purpose of striking the bell with the clapper. In the preferred form of our invention, we provide one pin 10 on the face of the clutch disc in a position to actuate the resilient arm 61 when the platen II of the typewriter has rotated to an extent corresponding to a letter size sheet of paper and we provide a second -similar pin 1I'to actuate the resilient arm for ringing the bell when the platen of the typewriter rotates to an extent corresponding to the length of a legal size sheet of paper in the typewriter. When the pin 10 rotates slightly less than 180 from the initial position shown in full lines in Fig. 2, lit encounters the underside of the resilient arm 61, and upon continued rotation of the clutch disc and pin first deilects the arm to the dotted position shown in Fig. 2 and then releases the arm whereupon the arm swings downwardly to carry the clapper 69 against the bell. The impact causes an audible signal to warn the operator that typing should cease at the end of the current line to provide the desired bottom margin for a page of letter size. If a legal size sheet is in the typewriter, the optime to indicate that the bottom 'margin has been reached.

Since the clutch disc 41 is rotated in clockwise direction by the power of the typewriter mechanism. it will move upwardly against fairly stiff resistanceon the part of the bell-ringing arm 61, but the return movement of the clutch disc, actuated by the relatively light torsional spring 56, may not have suflicient force to overcome .the same resistance on the part of the bell-ringing arm. A feature of our invention in this respect is the conception of a resilient bell-ringing arm that will offer substantially less resistance to downward iiexure than to upward exure. One form of such an arm may consist, as shown in the drawing, of two leaf springs that normally lie together, a lower relatively light spring 13 that extends into the path of the pins 10 and 1|, and an upper stiier spring 14 that falls short of the path of the `two pins. The lower spring may carry the clapper 69 and the upper spring may be cut away as indicated at 15 to clearthe clapper. It is apparent that clockwise rotation of one of the pins 10 and 1I past the arm 61 will deect both of the leaf springs 13 and 14 so that the force of the spring 14 will be given to the downward movement of the clapper 69; but the counter-clockwise movement of one of the pins past the yielding arm 61 will have the burden of deiiecting only the lower and lighter leaf springs 13.

The operation of our invention will be clear from the foregoing disclosure. When a new sheet of paper is inserted in the typewriter and the operator desires to be warned when the bottom margin of the sheet is reached, the typist will momentarily shift the handle 53 to the right when the fresh sheet is at a predetermined position in the machine. For example, in the preferred practice of our invention, we contemplate having the described mechanism so adjusted and arranged that if the handle 53 is manipulated to release the clutch disc as soon as the top edge of a fresh sheet initially appears in front of the platen I l, the signal mechanism will be synchronized with the sheet of paper. This initial manipulation of the lever 53 is the only attention to the device required by the typist, the sheet in the machine being typed in the usual manner. As soon as the platen rotates to a position corresponding to the last line that is to be typed on av sheet of letter size, the first of the two pins will cause the signal to sound, and if the typing is continued thereafter in the case of a legal size sheet, the bell will ring again at the proper time.

If the friction disc 41 is not released by movement of the handle 53 at the beginning of ya new sheet, clockwise rotation of the friction disc' may be carried to the point where the member 60 comes to rest against the stop 8| on the opposite side of the stop from that shown in Fig 2. In such a situation the stop 6| limi-ts the clockwise movement of the clutch disc to prevent straining of the torsional spring 56, but the fact that the clutch disc 41 is held stationary against further clockwise rotation does not interfere with operation of the typewriter, since the frictional engagement between the clutch disc "and the gear 45 is light enough to permit the gear 45 to rotate independently of the clutch disc notwithstanding pressure from the leaf spring 49.

If it is desired to make the above described device adjustable with respect to the timing of the signal whereby the margin may be varied or the signal may be adapted to various lengths of paper, it is necessary merely to make adjustable the stop that determines the initial position of the clutch disc 41. For example, instead of the lilxed stop 6l, we may provide a stop block 80 that is movably mounted on the lower casing wa1l62 in the manner indicated by Fig. 4. The block 80 is shown with a threaded stem 8| extending downward through a guide slot 82 in the wall 62. A thumb nut 83 on the stem 8|A below the slot normally holds the block at a selected position. timing of the signal may be advanced or retarded by shifting the block 80 to the left or right respectively.

For the purpose of disclosure and to illustrate the principles involved, we have directed our description to the specific construction of a preferred embodiment of the invention. It will be apparent to those skilled in the art, however, that various changes and modications may be made and other forms employed without departing from the scope of our inventive concept. We reserve the right, therefore, to all forms of our invention and any changes and modifications thereof that come within the scope of our appended claims.

We claim as our invention:

. 1. The combination with a typewriter or the like of: a bell; a resilient arm; a clapper mounted on the resilient arm in a position ,to strike said bell; means rotatable in one direction from an initial position to flex said arm to cause said clapper to strike the bell, said resilient arm being adapted to permit said rotary means to return Theto its initial position with relatively little opposia signal mechanism movable from an initial disposition to a disposition eiiective to signal a bottom margin on a sheet in the typewriter; a rst yielding means continuously urging said signal mechanism toward said initial disposition; a member operatively connected to said signal mechanism; a member operatively connected to said sheet-advancing mechanism of the typewriter to be driven thereby; a second yieldingy means normally pressing one of said members against the other to operatively and frictionally interconnect said sheet-advancing mechanism of the typewriter with said signal mechanism for driving the signal mechanism in opposition to said rst yielding means; and manual means for operation at the beginning of typing a page to relieve the pressure of said one member against the other member to release said signal mechanism from operative connection with the sheet-advancing mechanism thereby to permit said ilrst yielding means to return said signal mechanism to said initial disposition.

3. The combination with a typewriter or the like having a sheet-advancing mechanism, of: a signal mechanism movable from an initial disposition to a disposition effective to signal a bottom margin on a sheet in the typewriter; adjustable stop means cooperative with said signal mechanism to adjustably determine said initial disposition thereof; a first yielding means continuously urging said signal mechanism toward said initial disposition; a movable member operatively connected to said signal mechanism; a movable member operatively connected to said sheet-advancing mechanism of the typewriter to be driven thereby; .a second yielding means normally pressing one of saidl members against the other to operatively and frictionally interconnect said sheet-advancing mechanism of the typewriter with said signal mechanism for driving the signal mechanism in opposition to said rst yielding means; and manual means for operation at the beginning of typing a page to relieve the pressure of said one member against the other member to release said signal mechanism from operative connection with the sheetadvancing mechanism thereby to permit said first yielding means to return said signal mechanism to said initial disposition.

4. The combination with a typewriter or the like having a sheet-advancing mechanism, of: signal means; means movable from an initial ineffective position to a position to actuate said signal means; a first yielding means continuously urging said movable means toward said initial position; a member operatively connected to said movable means; a member operatively connected to said sheet-advancing mechanism of the typewriter to be driven thereby; a second yielding means normally pressing one of said members against the other to operatively and frictionally interconnect said sheet-advancing mechanism of the typewriter with said movable means for driving the movable means in opposition to said iirst yielding means: a third yielding means adapted to force said members apart, said third yielding means exerting less force than said second yielding means whereby the third yielding means is normally restrained by the second yielding means; and manually operable means to retract said second yielding means to permit said third yielding means to space said two members apart to release said movable means from operative connection with said sheet-advancing mechanism of the typewriter thereby to permit said first yielding means to return said movable means to said initial position.

5. The combination with a typewriter or the like having a sheet-advancing mechanism, of: signal means; means movable from an initial ineiiective position to a position to actuate said signal means; an adjustable stop means cooperative with said movable means to vary said initial position; a first yielding means continuously urging said movable means toward said initial position; a member operatively connected t-o said movable means; a member operatively conected to said sheet-advancing mechanism of the typewriter to be driven thereby; a second yielding means normally pressing one of said members against the other to operatively and frictionally interconnect said sheet-advancing mechanism of the typewriter with said movable means for driving the movable means in opposition to said first yielding means; a third yielding means adapted to force said members apart, said third yielding means exerting less force than said second yielding means whereby -the third yielding means is normally restrained by the second yieldin lmeans;'and manually operable means' to retract said second yielding means topermit said third yielding means to space said two members apart to release said movable means from operative connection with said sheet-advancing mechanismA of the typewriter thereby to permit said rst yielding means to return said movable means to said initial position.

6. As a new article of manufacture, a marginindicating accessory for use with a typewriter or the like having a rotary platen, comprising: a housing adapted to be mounted on said typewriter; signal means carrled by said housing and movable from an initial position to a signal position; a first yielding means continuously urging said signal means towardsaid initial position; a rst clutch member in said housing; means adapted to connect said clutch member operatively with said platen; a second clutch member coaxial with said first clutch member and opera.- tively connected with said signal means, one of said clutch members being movable into and out of frictional engagement with the other; a second yielding means normally urging said movable clutch member into said frictional engagement with the other clutch member to operatively connect said rotary platen of the typewriter with said signal means for actuating said signal means in opposition to said first yielding means; and manually controlled means to space said clutch 'members apart thereby to permit said first yielding means to return said signal means to said initial disposition.

7. As a new article of manufacture, a marginindicating accessory for use with a typewriter or the like having a rotary platen, comprising: a housing adapted to be mounted on said typewriter; signal means carried by said housing and movable from an initial position to a signal position; an adjustable stop means cooperative with said signal `means to vary said initial position thereby to vary the extent of movement of the signal means from said initial position to said signal position; a first yielding means continuously urging said signal means toward said initial position; a clutch member; means adapted `to connect said clutch member peratively with said platen; a clutch member o eratively connected with said signal means, one of said clutch members being movable into and out of frictional engagement with the other; a second yielding means normally urging said movable clutch member into said frictional engagement to operatively and frictionally interconnect said platen with said signal means for moving the signal means to said signalling position in opposition to said firstv J. ARNOLD VARNEY. G. HANNAN VAN BRUNT.

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