US2487834A

US2487834A - Ribbon reversing mechanism for writing machines

Info

Publication number: US2487834A
Application number: US652752A
Authority: US
Inventors: Stolz James Marshall
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-03-07
Filing date: 1946-03-07
Publication date: 1949-11-15
Anticipated expiration: 1966-11-15

Description

Nov. 15, 1949 J. M. STOLZ 2,487,834

RIBBON REVERSING MECHANISM FOR WRITING MACHINES Filed March 7, 1946 Patented Nov. 15, 1949 RIBBON REVERSING MECHANISM FOR WRITING MACHINES James Marshall Stolz, Los Angeles, Calif.

Application 'M archfl, 1946, Serial No. '652,752

2 Claims.

(Granted under the act of March 3, 1883, as,

means is provided for the automatic reversal of the inked ribbon when it has become completely wound upon one spool, and manual reversal is necessary. Several disadvantages arise from this condition. Frequently, an operator will reverse the ribbon well before the proper time, and this results in nonuse of a substantial portion thereof. On the other hand, an operator in some cases may fail to note that reversal is necessary; the machine then types on one part of the ribbon only, reducing the clarity of the printed matter and perhaps wearing a hole in the ribbon. In

extreme cases, breakage of the ribbon occurs.

The principal object of this invention is to provide a novel means for automatically reversing the ribbon in a typewriting machine of the nature indicated so as to eliminate the aforementioned difliculties.

Other objects will be apparent from a reading of the following specification and claims.

The single drawing is a front View, partly broken away, of the ribbon reversing mechanism of my invention.

Referring to the drawing, the typing and ribbon winding elementsin themselves substantially conventional-may be seen to include a typewheel I0 having numerals, letters and other indicia on the periphery thereof, the typewheel being adapted to be driven by a power source (not shown), two ribbon spools II and I2, provided with toothed driving wheels, as I I and I2, respectively, and an arm I5 having two teeth I5 and I5", the first being adapted to cooperate with wheel I I' and the second with toothed wheel I2. the same power source which drives print wheel I0; its action is to engage the toothed wheels II and I2 and to wind the ribbon 2U first in one direction and then in the other.

In a construction of this nature, difilculty is 50 encountered with any arrangement which depends for shifting arm I5 upon the strain which gradually builds up in the ribbon when the ribbon is run completely off one spool since the first action is to move arm I5 out of engagement with 5 amended April 30, 1928; 370 O. G. 757) Arm I5 is driven through an eccentric by 45 For the true scope of the invention, reference its cooperating ratchet wheel and thus prevent further advance of the ribbon.

Briefly, my invention provides means for preventing. any movement of arm I5 until enough strain has been accumulated to. snap the arm quicklyto its secondoperative position, namely (according to the drawing), in engagement with ratchet wheel I2.

According to my invention, the ribbon 20 is threaded through the apparatus in substantially conventional manner, as from spool II, through guides 2I, 22, and 23, and to spool I2. Guide 22, it will be understood, is furnished with an opening 22' through which a hammer (not shown) may cooperate with typewheel I0 to cause a character to be printed.

Assuming that the parts are in the conditions shown in the drawing, the ribbon being almost completely wound upon spool II, the eyelet 30, which is located adjacent the end of ribbon 20, will catch in the guide 23. As ratchet wheel II continues to step, lever 3 I pivoted at 32, will move under the urging of eyelet 3!! and abut against lever 33, pivoted at 34. Movement of lever 3|, therefore, first increases the tension on spring and then, acting through lever 33, moves pin 36, normally bearing against plate 31 above the corner 39 of said plate. It is this pin which prevents premature movement of arm I5. The parts are so calculated that by the time pin 36 clears plate 31 spring 35 is under sufficient tension to move arm I5 rapidly into engagement with ratchet wheel I2, notwithstanding the restraining influence of spring 40.

At the same time, pin 45, urged by spring 46, shown in the drawing as beneath the lower edge of plate 31, moves into a position substantially like that previously occupied by pin 36 but against the opposite side of plate 31.

The operations are then repeated except that ratchet wheel I2 is rotated by tooth I5 of arm I5 and the ribbon wound upon spool I2.

The foregoing description is in specific terms, and many modifications will suggest themselves.

should be had to the appended claims.

I claim:

1. In a ribbon reversing mechanism for a writing machine, including two ribbon spools and a ribbon having elements adjacent the ends thereof of substantially greater thickness than the ribbon, two ratchet wheels each adapted to drive one of said spools, a ratchet adapted to drive said wheels alternately, and means for controlling 5 said ratchet including a pivoted lever having a ribbon guide thereon adapted to be engaged by one of said thickened elements, continued movement of the ribbon after such engagement resulting in movement of said lever upon its pivot, a spring associated with said lever and with said ratchet, said spring being adapted to have its tension increased by movement of said lever, and a second lever adapted when in one position to bear against said ratchet, said second lever being adapted to be moved out of engagement with said ratchet by said first lever after a predetermined movement of said first lever.

2. In a ribbon reversing mechanism for a writing machine, a first ribbon spool, a first ratchet wheel for driving the same, a second ribbon spool, a second ratchet wheel for driving the same, a ratchet having one normal position in engagement with the first ratchet wheel and a second normal position in engagement with the second ratchet wheel, and means for shifting said ratchet from each of said normal positions to the other including a first lever and a second lever, a first spring connecting said first lever and said ratchet, a second spring connecting said second lever and said ratchet, said levers being adapted to be put under strain by means adjacent the end of a ribbon, said springs being adapted to have their tension increased by the lever associated therewith as the same is put under strain, a first member and a second member, each having two normal positions and each