TAMBOURING. 



515 



on which it turns, and the point of connection com- 

 municating motion to the frame and the cloth. 



To ohtain precision and steadiness, the sides 

 of the pantograph are joined so that the centre of 

 their thickness is exactly in the perpendicular 

 plane of the cloth, and the axes of the joints are 

 also perpendicular to this plane, in which, con- 

 sequently, all the progressive movements are ac- 

 complished. This is obtained by fixing upon 

 the great upper beam D", an elbow piece d" (fig. 

 1. and 3.) having a convenient rising, upon which 

 is fixed the piece d' that receives at the joint the 

 end of the side b d; this piece d' is fixed npon d" 

 with a bolt., but it has also an elongated hole, and 

 before closing up the screw hole, it is moved 

 forward or backward until it is got exactly in the 

 plane of the cloth. This done, nothing more is 

 required than to attach the frame to the angle/ of 

 the parallelogram, which is done by means of the 

 piece F'' (tig. 1 and 3.) 



It is now evident that if the workman take the 

 handle B" (fig. 1.), and move the pantograph in 

 any manner, that the point/ will desciibe a figure, 

 similar to that described by the point c, though one 

 sixth of the size, and the point/ will communicate 

 its motion to the frame and all that is carried by it. 

 Farther, if the frame be well supported in every 

 part, and caused to move in the same level, each of 

 its own points, and of those which are fixed with 

 it, will describe exactly the same figure as the point 

 /. Thus, by the moving of the pantograph, each 

 point of the machine describes a figure the same as 

 that described by the point/; and consequently the 

 same as that described by the point c, but only one 

 sixth of the size. It is sufficient then to give the 

 workman, who holds the handle B", a design six times 

 as large as that wished to be done by the machine, and 

 at the same time, to arrange it so that he will both 

 easily and surely go over all the tracings of the 

 design with the point c; to facilitate this, they fix 

 into c, perpendicular to the level of the parallelo- 

 gram, a small rod terminated by a point C'', and 

 place the design upon a vertical table E, parallel to 

 the plane of the cloth and of the parallelogram, and 

 draw it back only the length of the rod c C" (fig. 1 . 

 and 2.) ; this table is supported by an iron rod e ', 

 which is itself fixed upon a metal foot E' (fig. 1.), 

 which serves other purposes also, as we shall after- 

 wards see. The frame, loaded with its beams and 

 cloth, forms a very great weight ; and whilst it is 

 necessary that it should be kept exactly in a level, it 

 is no less necessary that it should move so easily that 

 the workman may carry the point of the pantograph 

 over the table without effort or uncertainty. 



1. A cord e (fig. 1.) attached to the side of the 

 pantograph b c passes over a returning pulley and 

 carries at its other end a weight which the work- 

 man can graduate at pleasure ; this weight balances 

 the pantograph, and tends, in some measure, to 

 lighten the frame. 



2. The upper side of the frame F' bears two pro- 

 jecting sockets, of which there is a side view given 

 in E" (fig. 3) ; each of these has a long horizontal 

 slit, in which the bolt e" (fig. 1. and 3.) can work 

 with very little friction, and which thus serves as a 

 conductor to keep every part of the upper frame to 

 its level ; for the bolts e" are fixed in the great 

 beam D" ; the length of the slit in each socket E" 

 should equal the range of lateral motion. 



3. The under side of the frame bears two hori- 

 zontal rails H and H (fig. 1.) each fastened by two 

 claws h h, slightly bent to the left, as is seen in h 



(fig. 2.) ; each of these rails is fitted into the hollow 

 of a pulley H' (fig. 1.) the bearer of which, of an 

 oval form, (fig. 4.) is supported upon two triangular 

 edges h' h' on the two branches h'', which form 

 the extremity of a forked lever H", of which there 

 is a side view in fig. 2. ; the two levers similar to 

 H" ought to be bound together, in order that the 

 sides of the frame may be equally supported ; for this 

 reason, they are united by the beam or axle I', the 

 two extremities of which are supported upon metal 

 legs (fig. 2.) ; a counter-weight I, resting upon the 

 end of the levers H", and capable, at pleasure, of 

 being brought nearer to or removed farther away 

 from the centre of support, exerts an upward pres- 

 sure upon the frame, which, without hindering its 

 motions in any way, prevents it from leaving the 

 original level for which the pantograph was regu- 

 lated ; the length of the rails H ought to be equal 

 to the range of the lateral motion of the frame ; and 

 the arms of the levers H" ought to be so long, that 

 the arc which they cause the edges h' of the sup- 

 port of the pulley to describe, form a right line with 

 the highest rising or lowest descent of the frame. 



4. Lastly two conductors i i (fig. 1.) supported 

 on metal feet, present vertical slits, in which the 

 lower side of the frame F' remains fixed. 



Arrangement of the Carriages Before describing 



the arrangement and action of the pincers that bear 

 the needles, we shall endeavour to explain the ar- 

 rangement of the two carriages that carry the 

 pincers and all their mechanism. These carriages, 

 both exactly similar, are placed one at the right and 

 the other at the left of the frame (fig. 2.). The 

 same letters are used in describing their correspond- 

 ing parts. 



Each carriage performs its movements upon an 

 iron rail, composed of two rods well dressed and 

 adjusted horizontally, one at either end of the ma- 

 chine. One of these rods may be seen in its place al 

 K(fig. 2.); there is also a side view of it a little to the 

 right, under No. 2. and a plan of it is shown in fig. 

 5. ; the two projecting portions h k are bolted down 

 upon two brackets, which are themselves fixed upon 

 the two vertical supporters AC and AB of the 

 frame ; one of the brackets is seen to the left of 

 fig. 1. ; the corresponding bracket of the other rod 

 is seen at the right against .the supporters A'B'. 

 The carnage itself is composed of a long hollow 

 cast metal cylinder L (fig. 1. and 2.) having at each 

 extremity a grooved wheel L', which revolves upon 

 the rail K ; these wheels are mounted upon a piece 

 I' forked at the two ends to receive their axes, and 

 the piece /' itself is bolted upon an appendage / (fig. 

 1. and 6.) cast along with the cylinder L. 



The carriage, thus constituted, preserves its equi- 

 librium perfectly secure upon the rods K, and so in- 

 fluences the whole, that the cloth may, with the 

 greatest ease, be moved backward and forward so as 

 to enter or draw the needles. 



But to avoid employing a person for these alter- 

 nate movements of the carriage, M. Heilmann has 

 by an ingenious construction enabled the workman 

 managing the pantograph, without moving from his 

 place, or at all inconveniencing himself, to guide the 

 carriages, and regulate at pleasure the extent of 

 their course and the rapidity of their motions. 



A pulley J (fig. 2.) is adjusted to the supporter 

 AB, to the right of the frame, by means of the two 

 pieces J' and J" ; a similar pulley is adjusted at the 

 other end of the frame to the corresponding sup- 

 porter A'B' (fig. 1.). In this figure, the last only is 

 shown, the one fixed to AB being left out, to show 

 2 K2 



