US2757776A

US2757776A - Automatic ribbon rewind cut-off

Info

Publication number: US2757776A
Application number: US371331A
Authority: US
Inventors: Vincent J Gilmore
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1953-07-30
Filing date: 1953-07-30
Publication date: 1956-08-07
Anticipated expiration: 1973-08-07

Description

1956 v. .1. GILMORE AUTOMATIC RIBBON REWIND CUT-OFF 5 Sheets-Sheet 1 Filed July 30, 1953 INVENTOR VINCENT J. GILMORE BY Qm JYTTORNEY 1956 v. J. GILMORE 2,757,776

AUTOMATIC RIBBON REWIND CUT-OFF Filed July 50', 1953 3 Sheets-Sheet 2 F IG.2

INVENTOR VINCENT J. GILMORE BY Q c 1956 v. J. GILMORE AUTOMATIC RIBBON REWIND CUT-OFF 5 Sheets-Sheet 3 Filed July 50, 1953 INVENTOR VINCENT J. GILMORE Q 4 CIYTTORI;:;M

United States Patent .AUTOMATEC RHBRON REWIND CUT-OFF Vincent J. Gilmore, Wappingers Falls, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application July 30, 1953, Serial No. 371,331

8 'Claims. (Cl. 197-151) This invention relates to typewriting machines, and more particularly to an improved ribbon winding mechanism for such machines.

When the ribbon of a typewriter becomes worn and needs to be replaced by a new ribbon, it is necessary that the operator either manually rotate the ribbon spool which has the most ribbon wound thereon until the remaining spool is exhausted, or make use of some mechanical rewinding mechanism.

The Hazleton Patent 2,540,031 discloses a ribbon rewinding mechanism which operates continuously as long as a rewind key is held depressed. As soon as the ribbon is completely wound on one spool, the mechanism automatically reverses the winding operation if the key is held depressed. With the Hazleton'device, the operator must visually determine when the ribbon is wholly wound on one spool. At this point, the operator must release the key before the reversing mechanism operates to Wind the ribbon back on the empty spool.

'The manual rotation of the ribbon spool is slow, tedious, and very apt to soil the hands of the operator. The mechanism disclosed by Hazleton is faster but requires the careful and continuous attention of the operator.

Abroad object of the present invention is to provide an improved ribbon winding mechanism.

Another object of the invention is to provide an improved ribbon rewinding mechanism which operates by the depression of a key to rewind the ribbon on one or the other of 'two spools. Y

Yet anotherobject is to provide an improved power operated ribbon winding mechanism which operates continuously, upon the depression of a key, until all'the rib bon is wound on one or the other of two ribbon spools and then stops automatically.

'Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the "accompanying drawings, which disclose byway of example, the principle of the invention and the best'mode Whi'ch'has" been contemplated of applying that principle.

In the drawings:

Fig. ,1 is 'a sectional view of a typewriter showing a single type bar and its actuating mechanism. Y

Fig. '2' is a side elevational view of the improved ribbon winding device in its normal inoperative position. Fig. '3 is an enlarged viewof mechanism partially shown in Fig. Z'for actuating a power unit to effect stepby-step winding of the; ribbon. I r

"Fig.- 4' is a detail view of certain parts of the winding mechanism shown in Fig. 2.

Figs. 5 and-6 are views-similar to Fig. 4 but showingparts indifferent'positions. 1 Y InFig; 1 is shown a vertical section'of a power operated: typewriter in which keys 1 are pivoted-Onacross rod 2 and guided at their front ends bya-suitab'lekey comb 3, the keys being restored by springs 4. The keys I control power mechanisms which are driven by a power roller 6 normally rotating counterclockwise, as viewed in Fig. 1. Each keycontrols its own power unit, all of which coact with the power roller 6 to operate the corresponding type bars 7.

Each power unit includes a lever 8 which is pivoted by means of a notch 9 on an individual fulcrum bar 11 mounted on a support bar 12. The levers 8 are held in engagement with the bars 11 by springs 13 anchored to suitable lugs on the bars 11. The upper end of each lever 8 is connected bya link 14 to an arm 16 on the associated type bar 7 which is pivotally mounted at a point 17.

Each power unit also includes an L-shaped lever 13 pivoted at 19 on the lever 8 and urged in a counterclockwise direction by a spring 21 anchored to an ear formed on the lever. An interposer 22 having an upper lug 23 and a lower lug 24 is pivotally mounted at 26 on the lever 8 and is urged in a clockwise direction by a spring 27. The depression of the key 1 causes an extension 28 of the lever 1 to engage the lug 23 and rock the inteiposer 22 in a counterclockwise direction. The lug 24 then forces the lever 18 in a clockwise direction and causes the serrated tread portion 29 of the cam to engage the power roller 6 and be gripped thereby. Rotation of the power roller causes the'cam 18 to swing about its pivot 19, and due to the eccentricity of the cam tread 29 with respect to the pivot 19, eflect'a rocking of the lever 8 in a clockwise direction about the pivot 9, against the tension ofthe spring 13 thereby actuating the type bar 7 to printing position.

Pivotally mounted on the framework of the machine is a cross shaft'31 on' which is pivotally mounted a universal bar or bail 32. This bail 32 is engaged by the nose piece 33 of the lever 8 whereby eachtime the lever is operated, the bail 32 is actuated in a counterclockwise direction. This movement of the bail 32 is utilized to trip a power unit in a manner to be explained.

Referring to Fig. 2, suitably supported in the machine framework by a fixed frame piece 36 is a power unit generally designated 37. The power unit 37 includes a suitable frame 38 pivoted at 39 on the frame 36. An elliptical cam 41 is pivoted at 42 in the frame 38, and the cam 41 is provided with two pins 43 located on diametrically opposite sides of the pivot 42. One of the pins 43 is normally engaged by an arm 44 pivoted at 46 in the frame 38. This arm 44 is urged in a clockwise direction by a torsion spring 47 partly coiled around the pivot 46 and hooked to lugs formed in the arm 44 and in the frame 38.

Also pivoted at 46 is a trip lever 48 having an offset lug 49 coacting with one of two pins 51 set in the cam 41 on diametrically opposite sides of the pivot 42 to limit rotation of the cam 41. The spring actuated lever 44 pressing on one of the pins 43 tends to rotate the cam 4-1 in a clockwise direction about its pivot point 42. In thispo'sition of the parts, there isa small clearance between the tread of the cam 41 and an enlarged portion 52 formed on or suitably secured to the continuously running power roller 6. 1

-When the trip lever 48 is pivoted in a clockwise direction about the pivot .46. by means to be disclosed, the

lug 49 is moved upwardly out of the path of the pins 51 and the cam 41 is rotatedslightly clockwise by actionof the spring tensioned lever 44 on one of the pins. 43. This slight clockwise rotation brings a high portion of the cam 41 into contact with the portion 52 of thepower-roller 6, causing clockwise rotation of the cam 41 about pivot-42.

-.-The trip lever 48 may be rocked in a clockwise direction by two diiferent meansto actuate the power. unit37. Referring to Fig. 3, the firstmeans is the above described individual type barpower units. Whenthe nose piece'33 of-fhe lever Sengages the .bail 32 and rotatesit in :a counterclockwise direction, the bailengages an arm 53 (Fig. 3), pivoted on the end of the cross shaft 31, and rotates it in a counterclockwise direction about the shaft 31, thereby shifting downwardly a link 54 joining the arm 53 and the actuating lever 48. The downward movement of the link 54 rotates the lever 48 in a clockwise direction and disengages the lug 49 from the pin 51. At the same time, a lug 56 also formed in the trip lever 48, is positioned in the path of movement of the second pin 51 so as to allow only one-half revolution of the cam 41. The trip lever 48 is then rocked in a counterclockwise direction by a spring 57 anchored to the frame 38 and to :1 lug carried by the trip lever 48. The lug 56 slips off the pin 51 but the pin 51 is then immediately engaged by the lug 49 and further rotation is prevented.

The second means for actuating the power unit 37 utilizes a member 58. Referring to Figs. 2 and 5. the member 58 is supported for vertical sliding movement by means of two

slots

59 and 61 engaging

studs

62 and 63 which are rigidly mounted in a frame plate adjacent the power unit 37. The member 58 is held in its normal, 1

raised position, Figs. 2 and 4, by a spring 67 tensioned between the frame stud 63 and a lug 68. The member 58 may be manually depressed to a position in which a notch 69 at one end of the slot 61 lies adjacent the stud 63. At this time, the member is pivoted by the spring 67 about the stud 62 to engage the notch 69 with the stud 63 for holding the member depressed. With the member in this depressed position, its lower end 71 acts against a pin 72 on the lever 48 for holding the latter in such a position that both the

lugs

49 and 56 on the lever. 48 are raised out of the path of the pins 51 and leave the cam 41 free to rotate continuously.

With the rotation limiting lug 49 and the repeat preventing lug 56 out of the path of the pins 51, the cam 41 contacts the roller portion 52 and rotates in a clockwise direction continuously until the trip lever 48 is allowed to rock in a counterclockwise direction under the tension of the spring 57, again placing the lug 49 in the path of the pins 51.

Due to the eccentricity of the lobes on the cam 41 and the action of a spring 73 connecting the frame 38 to a lug 74 on the fixed frame 36, an oscillating motion is imparted to the frame 38. Fixed to the frame 36 is a resilient bumper 76 for limiting the counterclockwise rocking movement of the frame 38.

Referring to Fig. 2, the cross shaft 31 is provided at its opposite ends with two arms 77, the left one of which is connected by a link 78 to the pivoted frame 38. The shaft 31 is rocked in synchronism with the oscillation of the frame 38 through the connecting link 78 and left arm 77. Attached to each of the arms 77 is a link 79 which actuatcs a ribbon mechanism associated with a ribbon spool. Fig. 2 shows the ribbon feeding mechanism located on the left hand side of the machine, but it will be understood that the two mechanisms are similar in construction and the description of one will sufiice for both. The side plate 81 of the main framework is formed with a large open, cut-out portion 82 to accommodate the ribbon mechanisms. Each of these mechanisms has a spool 83 and various control means mounted as a unit in the cutout 82 of the associated side frame 81, by means of a plate 84 attached by three screws 86.

The link 79 for the left hand spool 83 is connected to one arm of a lever 87 which is pivoted on a stud 88 carried by the plate 84. Another arm of the lever 87 has pivoted at 89 a feed pawl 91 which is urged in a clockwise direction by a spring 92 to engage the usual ratchet teeth 94 of the ribbon spool 83 when the ribbon feed mechanism is in condition to feed the ribbon ontothe left hand spool. When the power unit 37 is rendered operative in the manner described above to impart an oscillating movement to the shaft 31, both links 79 are oscillated up and down. This movement of the links 79 will cause the lever 87 associated with the pawl 91 to be actuated in a clockwise direction and, if the pawl 91 is engaged with the 4 teeth 94, the spool 83 will be rotated in a clockwise direction. It will be understood that the levers 87 for both feeding mechanisms will be oscillated each time the links 79 are oscillated, but the driving of a ribbon spool depends upon whether or not the pawl 91 for that particular spool is engaged with the ratchet teeth.

A mechanism is provided for causing the pawls 91 to engage the teeth 94 of the ribbon spools in alternation so as to cause one ribbon spool to feed until the other is exhausted and then to automatically render the other spool effective to feed. This mechanism is controlled by the tension produced in the ribbon when the free-running spool is exhausted. Pivoted at 96 on a plate 97, which is shaped somewhat like a letter G reversed right to left, is an interposer 98 which is connected by a link 99 to one arm of a tension lever 101 pivoted at 102 on the plate 84. The tension lever 101 is formed with a ribbon guide lug 103 having an open ribbon guiding slot formed therein and is urged in a clockwise direction against a stop lug 104 by a spring 106. Due to the fact that the ribbon is secured to the spools, sufiicient tension will be built up in the ribbon when a spool is exhausted to cause the tension control lever 101 of the free-running spool to pivot in a counterclockwise direction, while the tension control lever of the driven spool is unaffected. When all the ribbon has been wound onto one of the spools, the angles between the ribbon on the full spool and the lever 101 are such that an increase in tension on the ribbon has no tendency to swing the lever about its pivot. The ribbon at the empty spool, however, extends from the associated lever at such angles that an increase in the tension on the ribbon causes the lever to swing. Through the link connection 99, the interposer 98 will be rotated in a clockwise direction by the movement of the control lever 101 and into the path of an offset lug 107 formed on the lever 87. Consequently, the next oscillation of the lever 87 by the link 79 will cause the plate 97 of the free-running spool mechanism to be shifted upwardly rendering the pawl 91 effective to drive the previously free-running ribbon spool 83 with each clockwise oscillation of the lever 87. The plate 97 is formed with a long ofiset lug 108, like the cross bar of a G, disposed between the pawl 91 and the teeth 94 so that with the plate 97 in the lower position, Figs. 4 and 6, the pawl 91 is prevented from engaging the teeth 94, but when the plate 97 is shifted upwardly as in Figs. 2 and S, the pawl 91 will be permitted to engage the teeth 94.

A manual means also is provided for controlling the driving of the spools so as to obtain a winding of the ribbon onto the spool containing the greater portion of the ribbon. Pivotally connected to the left band member 97 at 109 and to the frame piece 84 at 111 is a manual lever 112, the operation of which will disengage the feed pawl 91 from the teeth 94 of one spool and engage the other feed pawl with the teeth of the other spool.

Referring to Fig. 4, the plate 97 'of the left hand spool 83 has a loose pin connection 113 with a lever 114 carried by a cross shaft 116 which is journalled in the stationary frame work. The plate 97 of the right hand spool (not shown) similarly has a loose pin connection 117 with a lever 118 disposed on the right end of the cross shaft 116 adjacent the plate 97 for the right hand spool feeding mechanism so that the

pins

113 and 117 are approximately 180 apart with respect to the cross shaft 116. When the left hand plate 97 is shifted upwardly, as in Figs. 2 and 5. to engage the left hand pawl 91 with the ratchet teeth 94 of the left hand ribbon spool 83, the cross shaft 116 is rotated in a clockwise direction by means of the pin 113 and the lever 114 to shift the right hand plate 97 downwardly by means of the lever 118 and the pin 117. This disengages the right hand pawl 91 from the ratchet teeth 94 of the right hand spool 83 and renders the right hand spool free-running.

In order to hold the plates 97 in their alternate shifted positions, the lever 118 is provided with an arm 119 which is engaged by one branch of a toggle spring 121,

the other branch of the spring being pivoted on a fixed stud 122 carried by the framework. The toggle spring 121 is fairly stiff with the result that the actuating lever 87 and the interposer 98 of either spool 83 need only raise the associated plate 97 a little beyond the dead center position of the toggle spring 121 to make the latter effective to snap the plate 97 to the alternate position.

Mounted on the cross shaft 116 adjacent its left end is a cam lever 123 having a bifurcated portion 124 receiving the pin 113 which is aflixed to the arm 114 and loosely engages the plate 97. Fixed to the right hand end of the cam lever 123 is a stud 125 extending into a slot 126 in the member 58. At one side of the slot 126 is a cam surface 127 adapted to cooperate with the stud 125 in a manner to be described shortly. Between the ends of the cam lever 123 is an arcuate slot 128 through which the frame stud 63 extends to guide the lever.

When the ribbon feedingmechanism for the left hand spool 83 is set as shown in Fig. 2, this spool is driven in a clockwise direction to wind up the ribbon 130. With the plate 97 for the left hand spool in its upper position, as shown, the cam lever 123 is in such a position that its stud 125 is located near the lower end of the slot 126 at a point between the sides of the latter. The plate 97 for the right hand spool is then in its lower position so as to make its pawl 91 ineffective, and the right hand spool rotates freely to pay off ribbon.

Upon actuation of any one of the type bars 7 (Fig. 1), the nose 33 of the lever 8 rocks the bail 32 to pull on the link 54 so as to swing the lever 48 in a clockwise direction about its pivot 46, Fig. 2. This releases the cam 41 for engagement with the portion 52 of the power roll, and the cam is driven through an angle of 180. As the cam is driven, the lever. 38 rocks about its pivot 39 and operates through the link 78 to rock the shaft 31. 'Since the links 79 are connected to arms 77 at opposite ends of the shaft 31, then both of the links 79 are operated to rock the levers 87 for actuating the feed pawls 91. Only the feed pawl for the left hand spool is effective with the parts in the positions assumed, and so this spool'is driven a short distance on each actuation of a type bar.

As soon as the ribbon has been wound onto the spool in Fig. 2 and a tension has been placed on the ribbon, the lever 101 at the other spool is rocked about its pivot, as described, to move its interposer 98 into the path of the lug 107 on the lever 87. When this lever 87 is next rocked by its link 79, the plate 97 for the right handspool is lifted to make'the pawl 91 associated therewith efiective to drive the spool. The lifting of the plate 97 and the pin 117 causes the lever 118 to be actuated so as to rock the shaft 116 in a counterclockwise direction. The lever 114 is rocked in the same direction with the shaft 116 and through the loose pin connection 113 causes the plate 97 in Fig. 2 to be lowered so that the pawl 91 for the left hand spool is ineffective. When the plate 97 in Fig. 2 is moved downwardly, the cam lever 123 is rocked, by means of the pin 113 and the bifurcated portion 124, to the position shown in Fig. 4. It will be noted that the cam lever now has its stud 125 located at the left hand side of the slot 126 and at a point spaced somewhat below the top.

If it is decided to drive the ribbon winding mechanism continuously when the parts are in the positions of Fig. 2 then the member 58 is depressed manually so that its lower end swings the lever 48 until the

lugs

49 and 56 are removed from the path of the studs 51. As the member 58 reaches it lowermost position, the spring 67 rocks the member counterclockwise to engage its notch 69 with the stud 63 so that the member is held depressed. The cam lever 123 now has its stud 125 engaging the right hand side of the slot 126 at the lower end of the cam surface 127, as shown in Fig. 5.

With the

lugs

49 and 56 removed from the path of the studs 51, the cam 41 is driven continuously to actuate the ribbon feeding mechanism repeatedly. As soon as all of the ribbon has been wound from the right hand spool to the left and a tension has been placed on the ribbon, then the lever 101 at the right hand spool is rocked to move the interposer 98 into the path of the lug 107 so that the plate 97 and the pin 117 at the right hand spool are lifted. This causes the lever 118 to be actuated for rocking the shaft 116 and swinging the lever 114 and its pin 113 to move the plate 97 for the left hand spool downwardly. As this operation takes place, the cam lever 123 is rocked counterclockwise from the position shown in Fig. 5 by means of the pin 113 and the bifurcated portion 124. The cam stud 125 then acts upwardly against the cam surface 127 to rock the member 58 in a clockwise direction and unlatoh it from the stud 63. This permits the spring 67 to lift the member 58 and release the lever 48 so that it can move to the position shown in Fig. 2 and stop the rotation of the cam 41.

When the plate 97 for the left hand spool is moved downwardly from the position of Fig. 2 to stop the driving of that spool, then the cam lever 123 is moved to the position of Fig. 6, and the member 58 moves from the position in Fig. 5 to the position in Fig. 4. The ribbon winding mechanism at the right hand spool is then operative to drive the latter. If the member 58 is now depressed from the position in Fig. 4 to the position in Fig. 6-.to cause a continuous driving of the spool, the cam stud 125 takes a position in the slot 126, as shown in Fig. 6. When the ribbon is completely unwound from the left hand spool and is subjected to a tension, the plate 97 at the left hand spool is lifted to reverse the direction of ribbon feed. At the same time, through the loose pin connection 113 and its bifurcated end, the cam lever 123 is rocked in a clockwise direction to the position of Fig.

5. This causes the cam studto act on the cam surface 127 for releasing the member 58 and stopping the feeding of the ribbon. The member 58 is returned by the spring 67 to the position in Fig. 2.

Therefore, to rewind the ribbon, the opera-tor has merely to initiate the operation by depressing the member 58 until said member is latched in its operative position, Figs. 5 and 6. The ribbon is then automatically wound into one spool and when the rewinding is complete the reversing mechanism operates automatically to disconnect the rewind mechanism. The full spool may. then be removed from the machine and replaced with a new spool thus requiring a minimum of ribbon handling and making it unnecessary for the operator to turn a spool by hand or to hold a rewind mechanism in its operative position or to visually detect when the rewinding operation is complete and then to manually halt thewinding operation.

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:

1, In a typewriter having a ribbon winding mechanism, a power actuator, a coupling means engageable with said power actuator for connecting the latter in driving relation with said winding mechanism, a manually operable member movable to a position for engaging said coupling means with said power actuator, means for latching said member in said position when moved thereto, means operable automatically in response to ribbon tension produced upon completion of ribbon winding to release said latching means, and means for moving said member from said position when released.

2. In a typewriter having a ribbon winding mechanism, a power actuator, a coupling means engageable with said power actuator for connecting the latter in driving relation with said winding mechanism, a manually operable member movable to a position for engaging said coupling means with said power actuator, means for yieldingly urging said member away from said position, means for latching said member in said position when moved thereto, and means operable automatically in response to ribbon tension produced when the ribbon has been completely wound for releasing said latching means.

3. In a typewriter having a ribbon winding mechanism, a power roller, means operable to couple said power roller and said winding mechanism, said coupling means including an actuator having an eccentric cam engageable with said power roller for intermittently driving said winding mechanism, a manually operable member movable to a position for effecting engagement between said cam and said roller, means for yieldingly urging said member away from said position, means for latching said member in said position when moved thereto, and means operable automatically for releasing said latching means when the ribbon is completely wound.

4. In a typewriter having a reversible ribbon winding mechanism, means operable automatically upon completion of ribbon winding for reversing said winding mechanism, a power roller, means operatively coupling said power roller and said winding mechanism, said coupling means including an actuator having an eccentric cam normally disengaged from said roller but rotatably engageable therewith, a manually operable member movable to a position to effect said rotating engagement between said cam and said roller for intermittently driving said winding mechanism, means for yieldingly urging said member away from said position, means for latching said member in said position when moved thereto, and means actuated by said reversing means upon completion of ribbon winding for releasing said latching means.

5. In a typewriter having a ribbon winding mechanism, a power roller, means operable to couple said winding mechanism with said power roller, said means including an actuator having an eccentric rotatable cam engageable with said power roller for intermittently driving said windding mechanism, means yieldingly urging said cam into engagement with said roller, means normally holding said cam in a position free from said roller, a manually operable control means movable to a position for releasing said holding means from said cam, means for latching said manual control means in said position when moved thereto, means yieldingly urging said manual control means away from said position, and means operating automatically upon the completion of ribbon winding for releasing said latching means.

6. A ribbon winding mechanism for a typewriter comprising, in combination, a pair of ribbon spools about which opposite end portions of the ribbon are wound, a ratchet connected to each of said ribbon spools, a pawl cooperating with each ratchet, a plate engageable with each pawl and movable to a position for holding its pawl free from engagement with its ratchet, means connecting said plates so that a movement of one to a position for holding its pawl free from one ratchet causes the other to move to a position engaging its pawl with the other ratchet, means for actuating said pawls to efiect rotation of said ratchets when engaged therewith, said actuating means including a power roll, a cam engageable with said power roll, means operatively connecting said cam to said pawls, means for yieldingly urging said cam toward engagement with said power roll, means normally holding said cam free from said power roll, a manually operable member movable to a position for re leasing said holding means, means for latching said member in said position when moved thereto, means operable upon a complete winding of the ribbon from one spool to the other for shifting the positions of said plates, and means operatively connected to one of said plates for releasing said latching means when a shifting of the plates takes place.

7. The mechanism of claim 6 in which said last mentioned means includes a cam surface on said manually operable member, and a cam lever connected at one end to one of said plates and engageable at its other end with said cam surface.

8. In a typewriter having a reversible ribbon winding mechanism, means operable automatically upon comple tion of ribbon winding for reversing said winding mechanism, a power roller, means for operatively coupling said power roller and said winding mechanism, means yieldably urging said coupling means to an uncoupling position, a manually operable member movable to a position for actuating said coupling means to efiect a coupling action, means yieldingly urging said member away from said position, means for latching said member in said position when moved thereto, and means actuated by said reversing means upon completion of ribbon winding for releasing said latching means.

References Cited in the file of this patent UNITED STATES PATENTS