514 



TAMBOIHI.\(J. 



the needles. Finally, by working two pedals alter- 

 nately with hi* feet, lie opens one hundred and thirty 

 pincers in the first carriage, after they have fixed 

 the needles in the cloth, and shuts the same num- 

 bers of pincers in the second carriage when they 

 have received the needles from the pincers of the 

 first. The girls have only to re-thread the needles, 

 and observe that none fall from the pincers. 



Referring to Plate LXXXVIII. we describe the 

 details of the machine under the following beads : 

 I. Arrangement of the Frame; 2. Position of the 

 Cloth ; 3. Arrangement of the Carriages; 4. Arrange- 

 ment of the Pincers. 



Arrangement of the Frame. The frame is of cast 

 iron, and requires to be fixed on a firm, immovable 

 base, not liable to be shaken by the movement of 

 t lie machine or the motions of the assistants. Fig. j 

 1. is a transverse section of the machine. Fig. 2. 

 is an elevation of the side where the workmen is , 

 placed ; in this figure the end of the frame forms 

 two equal rectangles ABBA, ABBA, similarly 

 placed, the one on the right, and the other on the 

 left, and united in the centre by a third rectangle of 

 less width, but more elevated, A D C A. These 

 rectangles are cast in one piece, and the horizontal 

 and vertical sections of the sides are perfectly equal. 

 The four feet of the frame, marked a, are firmly 

 fixed to the floor by screws. The other end of the 

 frame is perfectly similar to this, and the correspond- 

 ing parts are distinguished by the same letters with 

 an accent; thus, A'B'B'A', A'B'B'A', are the sym- 

 metrical rectangles, and A D'C'A' the connecting 

 rectangle, analagous to ADDA; and a' denotes the 

 six feet of this end, corresponding to the feet a in 

 fig. 2. Between each foot a, and its corresponding 

 one a', there is a cross-piece of cast-iron A", of 

 which the form and position are seen in fig. 1. 

 Thus at the lower part, the two ends of the frame 

 are bound together by six cross bars similar to A"; 

 at the extremities of each of the cross bars, there 

 are also supports a" to strengthen the frame- work ; 

 two of these are seen in fig. 1. At the upper part 

 the two ends of the frame are united by a single 

 beam D" (fig. 1.) connecting the corresponding 

 angles D and D*. At the top of fig. 3. a section of 

 this beam is shown, and in fig. 1. the form of its fore 

 and hinder edges are represented by a dotted line. 



Such is the arrangement of the frame, at once 

 light and durable, which carries all the mechanism of 

 the machine. It was necessary to give an exact idea 

 of it for the better understanding how the other 

 fixed pieces are supported, and the numerous mov- 

 able parts enabled to execute their movements. 



The length of the machine depends on the 

 number of pincers required. The model that was 

 exhibited carried 260 pincers, and was two yards 

 and a half in length ; but the scale of our plates 

 would not admit the representation of a machine so 

 long, and we have, therefore, shown one having 

 120 pincers ; the result of which is simply that our 

 cross beams A" and D'', instead of being two yards 

 and a half in length, are rather less than two yards. 

 The dimensions of the other parts are the same. 



The width of the frame should be the same in 

 all machines, as it determines the length of thread 

 that can be put into the needles, and it is an ad- 

 vantage that they should carry as long a thread as 

 those in Mr Hielmann's model. 



Position of the Cloth The pincers always pre- 

 sent themselves at the same point, and it is obvious ] 

 that a delicate movement must be given to the cloth, ! 

 in order that all the points through which the | 



m . dies are required to pass, may be successively 

 presented. The position of the cloth, and the 

 method of shifting it, are important particulars, 

 which we shall endeavour to describe in detail. 



The cloth is placed upon a large rectangular 

 frame, the four sides of which are visible in fig. 1. 

 i. e., the two vertical sides F F, and the upper and 

 under horizontal sides F F'. In fig. 1. are seen 

 two long wooden rollers G and G, with iron pivots 

 at the extremities, and resting upon the sides F of 

 the frame, in such a manner as to revolve freely. 

 Upon these rollers the fabric intended to be em- 

 broidered is wound, and stretched vertically to a 

 convenient degree of tension. Each roller has at 

 one extremity a small toothed wheel g </, furnished 

 with a catch, and by reference to fig. 3. it will be 

 seen that these wheels enable the workman to 

 tighten the fabric, or transfer it from one roller to 

 the other at pleasure. Two other rollers placed 

 above the former, but in a manner exactly similar, 

 are seen in fig. 3, and, though less distinctly, in fig. 

 1. One set of rollers presents the cloth to the up- 

 per needles, the other to the lower ones; but as the 

 two upper or two under rollers have not their axes 

 in the same vertical plane, the level of the cloth 

 G" (fig. 3.), will itself be inclined and presented ob- 

 liquely to the needles, if care be not taken to correct 

 and replace them exactly in the middle of the fnime 

 by means of a strong wooden ruler, fixed like the 

 rollers upon the vertical sides of the frame. The 

 form of this ruler is seen at G', fig. 3. 



The cloth should be stretched laterally as much 

 as the strength of the fabric will admit. This 

 being done, strips of brass are stitched upon the 

 borders, and afterwards the packthreads g" (fig. 1.) 

 are fastened to those strips, and these being drawn 

 to the sides of the frame F, stretch the cloth to the 

 degree of tension required. 



It remains to notice the ingenious contrivance 

 for moving the frame F, in all directions, without 

 suffering it to leave the vertical plane, and also how 

 the cloth is fixed upon it and partakes of its move- 

 ments, and is thereby presented to the needles in 

 such a way that all the required points are succes- 

 sively stitched and traversed by the thread. 



To obtain this result, Mr Hielmann has employed 

 the pantograph, the principles of which we proceed 

 to explain. 



Fig. 1. b b' fb" represents a parallelogram, whose 

 four angles b b' fb" are so jointed as to be made at 

 will either very obtuse or very acute ; the sides b b' 

 and b b" are elongated, the one towards the point 

 d, the other towards the point c, and these points 

 are so chosen that in one position of the parallelo- 

 gram the line c d, which joins them, may pass the 

 point/. This purpose may be accomplished in many 

 ways; for, the position of the parallelogram re- 

 maining the same, it is evident that if it be wished 

 to remove the point d farther from the point b", it 

 is only necessary to bring the point c towards the 

 point b'', or vice versa; but when once the distance 

 b'd, is fixed, it is evident that the distance b' c is a 

 necessary consequence of it. The principle of the 

 pantograph is this : It is sufficient that the three 

 points, d,f, and c, be in a right line in one single 

 position of the parallelogram, to cause them to be 

 in a right line in any position soever. 



On looking over figures 1, 2, and 3, we see in fig. 

 1. that the side A c has a handle, by which the 

 workman puts the instrument into action : fig. 2. 

 gives a side view of the angles and joints ; and fig. 

 3. gives a more distinct view of the supporting point 



