Patent GB-271825-A (GB)
Title: Improvements in or relating to shed-forming machines with a pattern comprising a perforated band of paper
IPC: D03C1/14
Filed: 1927-03-11
Abstract: 271,825. Staubli, H., Staubli, H., Staubli, R., and Staubli, H., (trading as Staubli & Co., Geb.). May 28, 1926, [Convention date]. Dobbies; jacquards.-In a shed-forming device with a paper pattern passing over a cylinder 1, during the stroke of a lifting-knife 12 two picks are simultaneously read off, one by means of needles 22<c> and the other by means of needles 22<a>. Each pick is read off twice, the cylinder 1 being fed after each pick, the distance corresponding to one pick, the pick previously read by the needle 22a being read by the needle 22<c>. During the forward rotation of the cylinder, the engagement of the hooks 14 with the lifting-knife 12 are governed by the needles 22<c>, the indications of the needles 22<c> being ineffective to control the hooks for the reason explained below, and the sheds for consecutive picks are thus correctly formed according to the indications of the needles 22<c>. When the device is rotated backwards, the needles 22<a> and not the needles 22<c> govern the engagement of the hooks 14, hence immediately on reversal the shed corresponding to the last pick is first re-opened instead of a new shed, so that the device acts correctly both for constant and alternating directions of rotation. In the case of a single lift dobby, the movement of the lifting knife 12 is governed by a cam 6, which is arranged, as shown in Fig. 3, to continue its backward movement a little after the hooks 14 have completed their backward movements, this lost motion disengaging the hooks 14 from the knife 12. The needles 22<a>, 22<c> govern respective driver needles 21<a>, 21<c> connected to spring-controlled bell-crank levers 16, the needles being all raised at times by bars 25, 26 on a spring-controlled bell-crank lever actuated by a cam 29, the rotation of the cylinder 1 occurring at this time. The needles 22a, 22<c> are subsequently allowed to fall and certain of them engage holes in the pattern, the driver needles 21<a>, 21<c> corresponding to such indicating needles moving into the path of the driving-bars 34, 35 on spring-controlled levers 32, 33 actuated by respective cams 30, 31 on a shaft 4, which may be the shaft of the cam 29. During the forward movement of the machine, the cam 30 acts first, the timing being such that this occurs whilst the knife 12 is moving backwards. Consequently certain driver needles 21<a> corresponding to lowered indicator needles 22<a> are actuated by the driving-bar 34 and the corresponding levers 16 are rocked, whilst other levers 16 remain in their original positions. As, however, it is immaterial whether the hooks 14 are raised or not at this stage, the indications of the needles 22<a> are ineffective. Just before the knife 12 moves forwards, the cam 31 comes into action, and the driving-bar 35 actuates the driver needles 21<c> corresponding to raised indicator needles 22<c>, so that the corresponding levers 16 are rocked and the corresponding hooks 14 allowed to engage the knife 12, whilst the hooks 14 corresponding to the lowered needles 22c are prevented from engaging the knife, the balance levers 40 and swing levers 41 being thus actuated according to the indications of the needles 22<c>. When the machine is reversed, from the position shown in Fig. 3, the driving-bar 34 again moves to the right and acts on the needles 21<a> and hooks 16 as the knife moves forwards to re-open the shed of the previous pick. The indication of the indicator needles 22<a> and driver needles 21<a> now govern the successive sheds. The application of the device to a double lift dobbv is described. The device is stated to be applicable to dobbies and jacquards.