US2894402A - Stepless gearing, suitable for driving travelling grates or similar devices - Google Patents

Description

Jul 14, 1959 2,894,402

. E. SZ'ASZ Y STEPLESS GEARING, SUITABLE FOR DRIVING TRAVELLING GRATES OR SIMILAR DEVICES Filed Jan. 4; 1954 IWVQTLZLOF '7 3 sheets sh'eet 1 E. szAsz July 14, 1959 2,894,402 STEPLESS GEARING, SUITABLE FOR'DRIVING TRAVELLING GRATES OR SIMILAR DEVICES 3 Sheets-Sheet 2 Filed Jan. 4, 1954 YWW 7 July 14, 1959 '5 51,052 2,894,402

STEIPLESS GEARING, SUITABLE FOR DRIVING TRAVELLING GRATES OR SIMILAR DEVICES Filed Jan. 4, .1954 3 Sheets-Sheet 3 QXQ?) 20 Y 5 0 50454035302520 15 10 5 0 m3 mm fee. 7 F795 Z 77ve?2Z0)- Emez-y dzzsz United States Patent STEPLES S GEARING, SUITABLE FOR DRIVING TRAVELLING GRATES OR SllVlILAR DEVICES Emery Szasz, Montreal, Quebec, Canada, assignor of onehalf to Saul Josephson, Montreal, Quebec, Canada Application January 4, 1954, Serial No. 402,085

1 Claim. (Cl. 74-117) This invention relates to a stepless gearing, suitable for driving travelling grates or similar devices, where a relatively slow, steady feed of the parts to be moved at an adjustable speed is required. Furthermore, the invention relates to the particular construction of individual elements of the gearing, the said elements being usable in combination with each other, and also independently in various ways.

The main object of the invention is to provide a gearing that will be particularly adaptable to travelling grates or similar devices and will meet the requirements of the trade better than do the known driving devices of this type. The known devices are generally very noisy and also take up a lot of space which is disadvantageous in a boiler room for example. Furthermore, the feeding speed is only adjustable in most cases by large steps or by means of complicated intermediate gearing. They are also imperfect as regards security against breakage of the members of the gearing due to sudden jamming of the feed.

All these disadvantages are eliminated in a simple manner by means of the invention.

According to the invention, the gearing comprises a lever which through pawls engages the circumference of a wheel that drives one of the driving shafts of the travelling grate or the like, and is connected to an adjustable double eccentric by means of an eccentric rod linked to one of its ends. The double eccentric is power motivated, for example by an electric motor, preferably via an intermediate gearing and an overload clutch.

The pawl mechanism consists preferably of a simple lever with two oppositely directed pawls which engage the outer and inner surfaces respectively of a flange on said wheel, thus making it possible for the lever to hang freely on the flange by the aid of the clamps alone and without any additional fixed mounting. Such a pawl mechanism has a minimum moving mass and works smoothly and practically without noise. Its assembly and upkeep are relatively simple and it is very durable due to its low wear.

The driving of the pawl mechanism via an adjustable double eccentric makes possible a continuous variation of the feeding speed over a wide range, in a very simple manner. Furthermore, this range of variation may be altered by changing the angular speed of the eccentric shaft, for example by selecting a faster or slower driving motor so that the gearing may at all times work under the best conditions.

A further advantageous feature of the invention is that the overload clutch is formed of a cone or sliding clutch that is built directly into the double eccentric. For this purpose, the co-operating bearing surfaces of the inner and outer eccentric discs are advantageously coniform and are pressed together under the action of a spring. When an overload is caused by jamming of the travelling grate or the like, the spring yields and allows relative sliding of the clutch surfaces. At the same time, and independently of their action as a resilient overload clutch, the

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eccentric discs which interengage at their conical surfaces, may be angularly movable relatively to one another so as to alter the eccentricity of the double eccentric.

A double function of the eccentric members is achieved in this way and a space saving, simple and cheap arrangement of the overload clutch is made possible.

In comparison with the often used shear pins which break in case of overload, the arrangement according to this invention has the advantage that the driving gearing can resume working immediately after removal of the overload. This is of particular importance in operat-' ing a travelling grate, where the overloads are mostly of a temporary nature. Thus an adjustable drive for travelling grates is provided that, in a simple manner, meets all the requirements demanded from such a drive. The gearing affords a practically noiseless drive, makes possi ble stepless gear changing and is protected against damage by the overload clutch. Over and above all these advantages, the gearing is of small dimensions, is light in weight and is liable to a minimum of wear, thus assuring many years of service.

Details of a practical form of the invention are illustrated in the accompanying drawings, wherein Fig. 1 shows entire gearing in side view, with some parts in section,

Fig. 1a shows the wheel in section on the line AB of Fig. 1,

Fig. 2 shows the lever with part of the wheel in longitudinal section, on the line C-D of Fig. 1,

Fig. 3 shows an enlarged side view of the adjustable double eccentric.

Fig. 4 shows in cross section, on the line EF of Fig. 3, the double eccentric with the built-in overload clutch, and

Fig. 5 shows a diagram of the feeding speed in dependence on the eccentric position, for various speeds, of the driving motor.

The gearing shown in the drawings serves to drive a travelling grate. On the driving shaft (not shown) of the travelling grate is keyed a wheel 1 which is provided with a T-shaped flange 2. At the side of the flange 2 hangs a fork-like lever 3 and its outer end is linked to the lower end of an eccentric rod 5 by means of a pivot pin 4.

The limbs of the fork of the lever 3 are spaced by a distance which is about equal to the width of the flange 2 so that the lever 3 may engage the wheel laterally. On that part of the lever 3 that lies beyond the wheel, an outer pawl 7 is pivoted by means of a pivot pin 6 which can jam on the external circumference of the flange Opposite to this pawl 7 on the inner side of the flange 2, two internal pawls 9 are pivoted to the respective sides of the wheel 1 by means of pivot pins 8. The internal pawls 9 co-operate with the internal surfaces of the flange '2, which are separated from each other by the wheel disc 1. The external pawl 7 and the internal pawls 9 are arranged somewhat oflset relatively to each other and have a slight clearance from the external and internal surfaces respectively of the flange. With movement of the eccentric rod 5 in one direction they clamp the flange 2 between themselves and entrain it, whilst upon movement in the other direction they free the flange and slide past it. A practically noiseless motion of the pawl mechanism is herewith obtained. As can be seen from the drawing, the lever 3 engages the flange 2 only with its pawls 7 and 9 and no further mounting is required for it. The limbs of the lever 3 that project over the wheel 1 are furnished with counter-weights 10. In order to obtain continuous lubrication of the pawl mechanism, an oil bath into which the flange 2 dips may be arranged below the wheel 1.

The eccentric rod 5 is inclined upwards and is secured at its upper end to a bushing 13 of a double eccentric 14 which consists of two parts held together by a bolt 12 (Pig. 3). An outer eccentric disc 15 is fixed on an inner eccentric disc 16 so that by a relative angular movement of the eccentric .discs a variation of the eccentricity of the double eccentric may be produced. The inner eccentric disc 16 is keyed by means of groove 17 on an eccentric shaft which may be driven .by any convenient source .of power. In the example shown, the eccentric shaft is composed of the Worm wheel shaft of a .worm gear 18 and its worm shaft 19 is driven by an electric motor 20.

An overload clutch is built into the double eccentric 14. The .interengaging surfaces of the two eccentric discs 15 and '16, Le, the inner surface 21 of the outer eccentric disc -15 .and the outer surface 22 of vthe internaleccentn'c disc 16 are .for this purpose made coniform so that the .twoeccentric discs form at the sametinie a cone clutch. The inner eccentric disc 16 is pressed by means of a spring 23 with its cone 22 into the cone 21 ofthe outer eccentric disc 15. This spring bears against an inner wall 24 of .the inner disc 1.6 at one end and against a cover 25 at the other end. This coveris fixed on the outer eccentric disc 15 by means of a screw 26. The size and strength of the spring 23 are such that both eccentric discs 15 and 16 are usually firmly pressed against each other. The torque of the eccentric shaft is thus transmitted to the outer eccentric disc 15 and by the eccentric rod via the lever 3 to the Wheel 1. When the maximum permissible torque is exceeded e.g. as a consequence of a sudden jamming of the travelling grate the spring 23 yields so that the inner eccentric disc 16 can rotate with its cone surface 22 in the .cone surface 21 of the outer eccentric disc without taking the latter along. In this way, the two eccentric discs act as a slipping clutch.

Furthermore, the twoeccentricdiscs 15 and 16 can be angularly adjusted relatively to one another, in order to vary theeccentricity ofthe double eccentric. forthis purpose, the. outer eccentric disc may be provided with means for effecting this. For example, the eccentric disc 15 is shownas formedwithone or more radial bores 27 in which a tommy barmay be-inserted, by means of which theouter eccentric disc 15 may be turned on the inner veccentric disc 16 against the actionof theclutch spring 23 .without the necessity of taking the clutch to pieces.

The operation of the mechanism will be clear without further description. The angular speedofthewvheel 1 and therewith the feeding speedof the traveling grate may be regulatedover a wide range in steplessmanner by adjusting the double eccentric 14. The range. of adjustmentof the .double eccentric can moreover be altered by suitable selection of the speedof theeccentric shaft.

The simplest way of doing this is to. use an electricmotor of suitable, speed. -In Fig. 5 of the drawing, the feed of a travelling grate is shown in metres. per hour plotted against theeccentricity of the double eccentric, the various curvescorresponding to different speeds ofrthe electric motor employed. The extremely vast range of adjustment of a mechanism according to the invention be seen from this diagram.

I claim:

A mechanical movement, comprising a wheel adapted to be coupled to a driving shaft, said wheel having a circumferential T-shaped flange, a fork-like lever provided with pawls adapted to co-operate with the cirumt n a fl n e o a d W e va a t .011 O Sai pawls cooperatin g with the outer surface of said flange and at least another of said pawls co-operating with the inner surface ofsaid flange, inner and outer eccentrics having an eccentric rod, said lever being linked to said eccentric rod at its end remote from said wheel and being at its outer end supported solely by the engagement of its pawls with said flange, said pawls being directed so that the movement of said eccentric rod in one direction causes said flange to be clamped between saidpawls and movement ofsaid rod in the other direction causing free movement of said pawls relative .to said flange, said lever carrying at least one counterweight ion itsend remote fromsaidendlinlredto saideccentric rod, the inner eccentric and the outer eccentric being angularly movable relatively toone another whereby .to vary the eccentricity of said eccentrics, said inner eccentric having a peripheral frusto-conical surface andsaidouter eccentrichavinganinternal frustoconical surface adapted to contact the frusto conica1 surface of .said inner eccentric, the .saidtwoeccentrics being axially movable re1a tivelyvto one, another wherebyto bring said frusto-conical v urfaces into and out of clutching engagement, a coiled compression spring ,on said inner .eccentric part and adapted ,to urge said frusto-conicalsurfaces into driving engagement with one another, said two eccentrics being capable of vslippingrelatively to one another in.r esponse to an overload, and a cover ,plate fixed on the outer eccentric, said ,spring hearing against an inner Wall of said inner eccentric at oneend and against gsaid cover plate .at the other end, and said outer eccentric being formed with at least onevbore textending radially inwards from the periphery of said outer eccentric ,andadap ted to cooperate with a bar adapted to be inserted intosaid bore whereby to turnsaid outereccentricon.said inner eccentric against the action. of. said spring.

References Cited inthe file of this patent UNITED STATES PATENTS 240,536 Peartree Apr. 26, 1881 265,309 Drury Oct. 3, 1-882 272,511 Angeli c Feb. 20, 1883 739,773 Arnold Sept. 22, 1903 861,723 Hansen V July 30, 1907 1,202,558 -Maurseth et al. Oct. 24, 1916 1,839,815 Teece Jan."5,-19-3-2 2,158,677 'Pallister et al. May 16, 1939 2,308,974 -Harper Jan. 19, ;19 43 2,633,215 Battaline Mar. 31,1953 2,749,264 Amrick June 5, 1956

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