The principle of Devoge’s border jacquard is shown in Fig. 103. C C is the rocking bar, for driving the cylinders, working on the centre D. It is driven by the levers F, G, and the connecting-rod E. The notches A and B fall over the studs on the cylinder frame, and can either be let down or raised, as required, by the cords K, L and the levers H, I. The machine is an ordinary double-cylinder one, and either griffe can be wrought to suit the cylinder that is in action. This machine can be used as an ordinary double-acting one, as a single-acting one raising both griffes together and bringing in both cylinders together, or as a border machine working one griffe and one cylinder at the same time.
Another method, similar to the above, is to have a double-cylinder machine with the cylinders wrought by the griffes, then have a stud on the crank-shaft wheel for raising one griffe, as for an ordinary single-acting jacquard, and the two connecting-rods from the griffes made so that either will work on it. A hook or catch can be put in any convenient place, so that when one connecting-rod is on the stud the other can be hooked out of the way. The rods can be made to slide on to the stud easily, and be fastened with a pin, so that the weaver can readily change from one to the other.
To obviate the vibration of the harness as much as possible, as well as to economise the wear and tear of it and to minimise the friction on the warp threads, especially in weaving patterns requiring heavy lifts, such as warp-faced patterns, Messrs. Priestley & Co., of Bradford, patented an open-shed jacquard, the principle of which is shown in Fig. 104. It did not, however, prove successful, as the tacklers found some difficulty in working it.
The machine is an ordinary double-lift jacquard with one cylinder, and works in the ordinary way. The hooks are made as in Fig. 104, where it may be observed there is a turn or catch on the lower portion of the hook, at A. Above these catches is a set of bars, _b_, like a stationary griffe, and when the hooks are raised by the upper griffe, in the ordinary way, they spring over these lower bars and rest on them when the griffe begins to fall. All the hooks raised would thus remain up, were it not that the cylinder, pressing in for the second griffe (the machine being double-acting), which begins to rise as the upper one begins to fall, presses back those hooks that are not to be raised for the following shot, and as they are held by the griffe above, they spring back at the bottom, and, clearing the bars _b_, come down with the falling griffe. In this way the hooks, when once raised, remain up till pressed off by the card, so that in the case of working a warp stripe with an 8-leaf satin binding the hooks would only fall for every seventh pick.
