Patent GB-172255-A (GB)
Title: Improvements in typewriting machines with automatic shift-lock releasing mechanism for the paper roller
IPC: B41J11/14
Filed: 1921-03-24
Abstract: 172,255. Rogers, T. W., (Krupp Akt.-Ges., F.). March 24, 1921. Platen-shift mechanism; shift - key actions; key locks.-In machines having a shift-locking device that is released automatically upon operating the typing- keys, a releasing-key is provided for releasing the locking - device without operating the typing-keys, the arrangement enabling the platen to be restored to the normal position after being shifted in error; the releasing-key may be employed as a locking-key. In the mechanism shown in Figs. 1 and 2, a bail D, pivoted at a<1> and provided with shift-keys d<1>, is connected to an arm F carrying a roller f<2> which engages the shift frame g<1>. A cross pin f<1> on the arm is guided by slots a<3> in a stationary bracket a<2>. A locking-bar N pivoted on the pin f<1> is formed with a lug n<3> for engaging a part a<5> of the bracket, and an arm n<1> for engaging a cross-piece k<2> on a releasing-member K. The releasing-member is formed with slots k<1> engaging a cross-pin f<3> on the arm F. A bail H, pivoted at a<1> and connected to the releasing-member, carries at each side a releasing-key h<5>. The bails D, H are connected by a spring J, pins h<2> on the bail H normally abutting on the bail D. On depressing either of the shift keys d<1>, the shift frame is raised and is then locked by the locking- bar N; on operating the typing-keys, the universal bar P releases the locking-bar by engaging a roller n<6> thereon, and the shift frame and mechanism return to the normal position. A strong returning-spring is connected to the bail D. To release the shift frame without operating the typing-keys, one of the releasing-keys h<5> is depressed momentarily and the releasing-member is thereby raised further, and by engaging an inclined lug n<2> on the arm n<1> effects release of the locking-bar, the parts then returning to the normal position. If the parts fail to return when the locking-bar is first released, the spring J causes the member K to descend, and the crosspiece k<2>, by riding over the top of the incline n<2>, again releases the locking-bar and permits the parts to return. To permit the printing of a series of capitals, each of the releasing-keys h<5> is adapted to serve also as a locking-key; for this purpose, the key is pivoted to the bail H and is formed with a nose h<10> for engaging a stop a<4>. When either key h<5> is depressed, the releasing- member K is raised, the cross-piece k<2> riding over the inclines n<2>, and pins h<3> on the bail H then engage the bail D and cause the arms F to raise the shift frame. The key is then rocked in opposition to a spring h<7> to bring the nose h<10> into engagement with the stop a<4> and thereby lock the parts in the shift position, the typing- keys being thereafter unable to effect release of the shift frame. In the mechanism shown in Fig. 4, the bail H consists of two sections, the front section being pivoted on the pins a<1> and provided with the releasing-keys h<5>, and the rear section H<12> having a pin-and-slot connection h<11> with the front section and being pivoted on pins R on the bail D. The section H<12> is formed with a cross-piece h<14> engaging the arms n<1> of the locking-bar N. On operating the releasing-keys, the front section of the bail moves from stops d<2> to stop d' on the bail D, and the section H<12> rocks and releases the locking-bar, the parts thereupon returning to the normal position. The bail D is connected to a strong spring E which returns the parts before the returning-springs T, M of the sections H<12>, N have time to act, the arrangement preventing accidental re-engagement of the locking-bar. The framework A is formed with a ledge a<6> for engaging the noses h<10> when the keys h<5> are used as locking-keys.