LACE MANUFACTURE 



31 



1307 



unless a certain small force of traction be employed upon the thread. The curvilinear 

 groove h h, sunk in each face or side of the carriage, has the depth shown in the 

 section at h. The groove corre- 

 sponds to the interval between the 

 teeth of the comb, or bars of the . 

 bolt, in -which each carriage is 

 placed, and has its movement. A 

 portion of that bolt or comb' is 

 shown at a, fig. 1307 in plan, and 

 one bar of a circular bolt machine 

 at 6, in section. If we suppose two 

 such combs or bolts placed with 

 the ends of the teeth opposite each 

 other, but a little apart, to let the 

 warp threads be stretched, in one 

 vertical plane, between their ends 

 or tips, we shall have an idea of 

 the skeleton of a bobbin-net ma- 

 chine. One of these two combs, in 

 the double bolt machine, has ait 

 occasional lateral movement called 

 shagging, equal to the interval of 

 one tooth or bolt, by which, after it 

 has received the bobbins, with their carriages, into its teeth, it can shift that interval 

 to the one side, and thereby get into a position to return the bobbins, with their 

 carriages, into the next series of interstices or gates in the other bolt. By this means 

 the whole series of carriages receives successive side steps to the right in one bolt, and 

 to the left in the other, so as to perform a species of counter- march, in the course of 

 which they are made to cross and twist round about the vertical warp threads, and 

 thus to form the meshes of the net. 



The mimber of movements required to form a row of meshes in the double tier 

 machine, that is, in a frame with two combs or bars, and two rows of bobbins, is six; 

 that is, the whole of the carriages (with their bobbins) pass from one bar or comb to 

 the other six times, during which passages the different divisions of bobbing and warp 

 threads change their relative positions twelve times. 



This interchange or traversing of the carriages with their bobbins, which is the 

 most difficult thing to explain, but at the same time the most essential principle of the 

 lace-machine, may be tolerably well understood by a careful study of fig. 1.308, in which 

 the simple line | represents the bolts or teeth, the sign 4 the black line of carriages, and 



the sign <J> the front line of carriages. H is the front comb or bolt bar, and i the back 

 bolt bar. The former remains always fixed or stationary, to receive the carriages as 

 they may be presented to it by the shogging of the latter. There must be always one 

 odd carriage at the end ; the rest being in pairs. 



No. 1 represents the carriages in the front comb or bar, the odd carriage being at 

 the left end. The black line of carriages is first moved on to the back bar i, the odd 

 carriage as seen in No. 1, having been left behind, their being no carriage opposite to 

 drive it over to the other comb or bar. The carriages then stand as in No. 2. The 

 bar i now shifts to the left, as shown in No. 3 ; the front carriages then go over into 

 the back bar or comb, as is represented by No. 4. The bar i now shifts to the right, 

 and gives the position No. 5. The front carriages are then driven over to the front bar, 

 and leave the odd carriage on the back bar at the right end, for the same reason as 

 before described, and the carriages stand as shown in No. 6. The bar i next shifts to 

 the left, and the carriages stand as in No. 7 (the odd carriage being thereby on the back 

 bar to the left). The back carriages now come over to the front bar, and stand as in 

 No. 8. The back bar or comb i shifts to the right as seen in No. 9, which' com- 



