About this item 2 Heat Setting (800 and 1200 watts) LCD Room Temperature Read Out Digital Thermostat Control,30 Minutes to 8 Hours Timer Setting Tip Over Cut-off Switch and Overload Thermal Protector Please refer the user manual for troubleshooting information Heating coverage:- 500 square feet

Arduino PWM fading example captured by JYETECH LCD digital storage oscilloscope

In contrast to the other metal detector in this issue, the present one works on the principle that the frequency of an LC oscillator changes when the inductance is altered. Any metal object brought near the inductor will modify the inductance. The degree by which the frequency changes depends on the nature of the metal and on the frequency. If the fre- quency is very high, a metal object will act as a shorted turn, which lowers the inductance, so that the fre- quency increases. If the frequency is low enough for eddy-current losses to be ignored, it is possible to distinguish ferrous from non-ferrous metals. The inductance required for an oscil- lator frequency of not greater than 200 Hz would be pretty difficult to make, and the oscillator in the present circuit, therefore, works at about 300 kHz. The inductance then needed is quite easy to make and consists of a single turn of coaxial cable as shown in the accompanying diagram. The circuit consists of oscillator T i, frequency-t...

Description (No Model.) W. H. JACKSON. CIRCULAR KNITTING MACHINE. No. 467,874. Patented Jan. 26, 1892. INVENTOR UNITED STATES PATENT OFFICE. WVILLIAM H. JACKSON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF TYVO-THIRDS TO JOHN BLOOD AND EDVARD BLOOD, OF SAME PLACE. CIRCULAR-KNITTING MACHINE. SPECIFICATION forming part of Letters Patent No. 467,874, dated January 26, 1892. Application filed June 9, 1890. Serial No. 354,701. (No model.) I plished by the raising and lowering of needles, as is well understood. In the ordinary non-automatic machines of this class it is usual to effect the continuous rotary movement by power, and when the change is made to reciprocating movement to shift the driving-belt onto a loose pulley and work by hand, a crank or winch being provided upon the driving-shaft for that purpose. The raising and lowering of the needles being also cf- 2 5 fected by the hands of the operator, much delay and inconvenience results from the necessity of such twofold manipulation. The object of my present invention is to provide means whereby the operator can re- 0 ciprocate the cylinder by means of the foot, leaving both hands free to manipulate the needles, the mechanism for this purpose being so combined with the power driving mechanism as to afford no interference therewith. 3 5 In the accompanying drawings, Figure 1 is a view in perspective of a knitting-machine embodying my improvements. Fig. 2 is a horizontal section, on an enlarged scale, through the driving-shaft which carries the fast and loose pulleys and showing some of the adjacent parts. Fig. 3 is a partial view in perspective of the treadle and adjacent mechanism. Figs. at and 5 are views of an alternative arrangement, Fig. at being a par tial horizontal section on the line of the prolonged axis of the driving-shaft, and Fig. 5 being merely a diagrammatic view of the treadle mechanism. Taking first the type shown in Figs. 1, i, and 3, A represents the table on which the base-plate B of the knitting machine is mounted, the canrcylinder being indicated at C, the needles at D, and the thread-guide at E. The cam-cylinder is driven in the usual manner by means of a bevel-gear F, having a hub Q, rigidly mounted upon the drivingshaft G, which carries the fast pulley K and loose pulley K. The belt J is driven by means of the main pulley I, mounted upon the shaft H. The belt-shifter M is rigidly attached by means of a head M to the end of a rod R, sliding horizontally in the guides V V and provided with a spring S, compressed between the guide V, and a collar 0', attached to the rod B, so as normally to tend to throw the belt onto the loose pulley K. Belt-shifting. levers P P, jointed together at p, are connected with the belt-shifter head M in such manner as that when they are thrown past the center at their joint the shifter'will be locked in position upon the fast pulley. Between the bevel-gear F and the loose pulley K, I mount freely upon the shaft G a sliding sprocket wheel or disk L, having holes or seats upon one face to engage with pins q 7 upon the proximate face of the hub Q, which, as before stated, is rigidly connected with the shaft G. The other face of the disk Lis provided with a shallow hub having an annular groove to permit engagement with a shifting- 8o arm I, attached to a head T, which slides upon the rod R. A spring 11, compressed between said head T and the guide V, tends normally to throw said head away from said guide and thus to throw the disk L out of engagement 8 5 with the studs q. The length of the head T is such that when the head M of the beltshifter moves towardit in the act of shiftingthe belt onto the loose pulley it will just strike said head after the belt has moved 0 clear of the fast pulley, and thereupon the continuation of the shifting movement for a very slight distance will throw the head T sufficiently along the rod to cause engagement of the studs q with their seats of the disk L. When, however, the converse movement of the shifter commences the headT will immediately follow the head M, (by reason of the tension of the spring u,) and before the belt has come into contact with the fast pulley the disk will have been shifted completely out of engagement with the studs q, so that no interference can take place between the respective groups of driving mechanism. The sprocket-wheel is provided with a chain belt N, whose openings are adapted to engage with the teeth Z of the sprocket-wheel, and said chain is attached at one end to a strong spring WV, secured to the table, and at the other is connected by means of a rod n to the treadle O, suitably pivoted to the floor. The operation of the device is as follows: Assuming that the leg of the stocking has been knit by continuous rotary movement and by means of the power driving mechanisrn, when the time for narrowing theheel has arrived, the operator throws the shifting-levers I P out of the locked position, and the spring S thereupon throws the rod R to the left and shifts the belt onto the loose pulley K. In completing this movement the head M has shifted the head T also to the left and caused the engagement of thedisk L with thestuds q. The operator then raises onehalf the needles by hand and by means of his foot depresses the treadle O, causing a half-reciprocation of the cam-cylinder. Upon releasing the treadle the spring XV causes a corresponding reciprocation in the opposite direction, and the operator,wi-th both hands free, lifts needle after needle into the idle series at tlie'end of each reciprocating movement until thenecessary-amount of narrowing has taken place, when the needles are returned one by one during the intervals of reciprocation. It will thus be-seen that a much more rapid manipulation is permitted, since the moveinent'of the treadle in no way'interferes with the manipulation of the needles, and not only is much time saved, but the risk of breaking or "displacing needles through hasty movementsof the hand is avoided. As soon as it is desired to return to the continuous rotary movementof the cylinder the operator has only to throw the belt-shifter levers P P in the'opposite direction, when the disk L will, by means of thespring u, be itself shifted out of engagement with the studs q, after which the belt J will then resume its position upon the fast pulley. An alternative form of device is shown in Figs. 4 and5. The. point of difference between this and the system just described lies chiefly, inthe fact that instead of using an intermediatesprocket-wheel, which is alter- .nately coupled to and uncoupled from the driving-shaft G, the treadle appliances are directly connected with a second bevel-gear F, sliding upon'a stationary shaft or'aXisG, secured in any convenient position beneath the bed-plate, said bevel-gear being adapted to 'engage with the horizontal bevel-gear F upon the bottom of the cylinder O,'(indicated by dotted lines in Fig. 4,) but being capable of shifting into and out of engagement with the teeth of said gear. The hub t of the gear F is provided with an annular groove to engage with an arm T, mounted upon the end of the belt-shifting rod, which in this instance is indicated by R. The arrangement of the belt-shifting devices upon the rod R and the relation of the fast and loose pulleys thereto are such that when the rod R moves to the left in Fig. 4, and consequently throws the gear F out of engagement with the gear F upon the cam-cylinder, the belt shall be shifted onto the fast pulley, and conversely the position of engagement between the gears F and F shall correspond with the position of the belt upon the loose pulley. In this system the treadle is represented at O and is connected by means of a cord N with the stud f upon one face of the bevelgear F. The return movement isefiected by a spring W, fastened at '11 to the floor and connected at the other end by means of a cord 0 to a second stud f, mounted upon the face of the gear F. It will thus be seen that the underlying principle of the two forms is the same, and for the purpose of defining my invention hereinafter I use the. term oscillating wheel to indicate, broadly, that member of the combinationupon which the treadle directly acts, irrespective of whether said member in turn acts directly upon the bevelgear of the cam-cylinder, as indicated in Fig. 4, or'operates through the medium of such parts as the gear F and hub Q, having Epins q to engage withsuchosci'llating wheel. Having thus described my invention, I claim 1. The combination, with the'cam-cylinder and a bevel gear in operative connection therewith-of a shaft, fast-and loose pulleys mounted upon said shaft, an oscillatingwheel mounted toslide axially and'bethroWn in and out of operative connection withsaid gear, a treadle and spring connected wit'h said oscil- 'lating wheel, a shifting-rod, a belt=shifter mounted 'thereon in proximity'to 'thefast and loose pulleys, and ashiftin arm also mounted thereon and connected with said oscillating wheel, substantially in the manner and for the purposes set forth. 2. The combination, with the cam-cylinder and a bevel -gear in operative connection therewith, of a shaft, fast and :loose pulleys mounted upon said shaft, an oscillating wheel also mounted upon said shaft and sliding axially thereon, a coupling device whereby said oscillating wheel may be'coupled to said bevel-gear, a treadle and spring connected with said wheel, a shifting-rod, a belt-shifter, a-head carrying'said belt-shifter and rigidly connected with said rod, a shifting-arm connected with said oscillating wheel and provided with a head sliding upon said :rod in proximity to the head of the belt-shifter, arm to couple the oscillating Wheel, substantially as set forth. WILLIAM H. JACKSON. Witnesses: JAMES H. BELL, E. REESE.