US2122200A - Apparatus for conveying objects treated in continuously operating furnaces - Google Patents

Description

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APPARATUS FOR CONVEYING OBJECTS TREATED IN CONTINUOUSLY OPERATING FURNACES Filed, Jan. 9, 1935 2 Sheets-Sheetl llllllllllll mllllllll .m

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APPARATUS FOR CONVEYING OBJECTS TREATED IN CONTINUOUSLY OPERATING FURNACES Filed Jan. 9, 1935 2 Sheets-Sheet 2 Efipua- /60 Patented June 28, 1938 PATENT OFFICE APPARATUS FOR CONVEYING OBJECTS TREATED IN CONTINUOUSLY FURNACES OPERATING Marcel Foul-ment, Paris, France Application January 9, 1935, Serial No. 1,060 In France March 10, 1933 16 Claims.

This invention relates to apparatus for conveying objects being treated in continuously operating furnaces.

In order to circulate objects intended to undergo heat treatment in continuously operating furnaces it has been proposed to provide. socalled rail conveyors therein, these being formed of two groups of bars or plates animated with a combined vertical and horizontal movement,

such that the advance movement of one group of bars, located in the elevated position and supporting at this moment the objects being treated, takes place at the same time as the return of the other group which is then in the low posi- 15 tion, without contact with the objects being treated.

In existing furnaces all the mechanism is located exterior of the furnace or at least outside of the hot parts, so as to be inspected, maintained and lubricated, and each bar of a group is affixed by transverse cast shoulders to an outerframe directly actuated by the mechanism. These shoulders or transverse members require for their passage slots or openings in the furnace walls, these latter admitting air,and"interfering with the heating of the furnace. If the number of bars is multiplied to permit the transportation of small objects the number of such openings will naturally be multiplied, thus resulting in complicated and 30 delicate mechanism. These defects, notwithstanding the advantages offered, make rail furnaces useless for delicate tempering operations.

The method of the present invention, which overcomes these defects, consists in subjecting intended to be treated in the furnace are placed, to a tractional force the resultant of which is exerted solely at one of their ends, while the lift-' An exemplary embodiment of a conveyor constructe'd in accordance with the invention is illustrated on the accompanying drawings as applied to a continuously operating furnace.

Fig. 1 is a longitudinal section of the furnace.

the conveyor bars or plates, on which the objects Fig. 2 is a horizontal section of the furnace at the level of the transporting platform (conveyor table), on .i I-li of Fig. 1.

Fig. 3 is a cross section of the furnace on Iii-'-l||lofFig.1. I 5

Fig. i is a partial perspective view on enlarged I scale showing the two sets of plates forming the conveyor platform.

Figs. 5 and 6 are sections of transverse shafts supporting the plates of the platform, showing the 180 displacement of two successive eccentrics supporting the plates.

Fig. '7 is a partial cross section of the platform, showing the conveyor plates in the high and low position.

Fig. 8 is a section on enlarged scale showing details of Fig. 1, and the mechanism positioned in the insertion or charging side of the furnace.

Figs. 9 to l'show paths which can be realized for any point of the conveyor platform.

Fig. 15 is a plan view of an example of the invention for afurnace having four 'zones of independent speeds.

Fig. 16 is a detail view illustrating an arrangement for adjusting the sleeve It, which carries the actuating cams It, ll, angularly in respect to the shaft 1 9. The continuously operating furnace I (Figs. 1 and 2) comprises the transverse shafts 2, of any number desired mounted in any suitable manner in the bearings 3 (Fig. 2) exterior of the furnace; each of these shafts carries eccentric pul-. leys or cams t, 5, all having the same eccentricity, but two successive pulleys are relatively displaced or staggered 180, as shown on Figs. 5 and-6, the result being that for a given position of shaft 2 the pulleys t (for example those of the even row) are in the upper position and the pulleys 5 (odd row) are in the lower position as shown on Figs. 5, 6 and '1; Fig. 4 is a perspective view of the corresponding relative position of plates 6, 1 carried by these pulleys.

Each shaft 2 carries at its free end, outside the furnace, a bevel pinion 8 (Figs. 2 and 3), meshing with a similar pinion 9 keyed on a. longitudinal shaft in actuated by a motor I ll through a suitable variable speed mechanism i2 and a speed reducer E3, in order to assure the transverse shafts such as 2 a continuous and uniform movement, at regulable speed.

The'eecentrics, such as t and t, are separated by the jaws M, of suitable form, forguiding the plates laterally.

The bar or plate assemblage is subdivided into two groups: some, the plates or bars 5 for ex- 55 ample, bearing on the eccentrics t which are in the upper position at a given moment (Fig. 6), the plates 7 then resting on the eccentrics 5 which are in the lower position (Fig. 5).

According to the invention the horizontal movement of plates 6, I, is realized by a mechanism outside the furnace, at the charging or removal side.

Each of the bars or plates terminates atone end of the furnace in a frame [5 (Figs. 1 and 8) in which are seated the eccentrics or cams l6, ll, relatively displaced or staggered intended to control the longitudinal movement of the different plates or bars and suitably brace each other as well as a common sleeve l8 mounted for adjustment on a shaft l9 (Fig. 8) which receives its movement from the main shaft I ll through any suitable drive, gear train or other device.

Disposed on the inner standard of frame 15 is a slide 20 which comes into position under the corresponding end eccentric pulley 4 or 5, as shown onFig. 8, so as to prevent the plates or plate jaws from rising when cams I6, I! rotate in the direction indicated by the arrow on Fig. 8. The sleeve l8, integral with the different eccentrics I6, I1, is integral with a shackle 2|, the free arms of which carry a worm 22 in mesh with a helicoidal gear 23 (Fig. 15) keyed on shaft l9. Rotation of the worm 22 by a wrench or crank 22a will produce an angular variation such may be desired of the keying of the sleeve l8 and thus of the eccentrics I6, I! relative to this shaft IS. The pinions 8, which drive or control the different transverse shafts 2 mounted at the interior of the furnace, are keyed invariably with respect to their drive shaft, and it is'thus possible to vary the relative keying of the advance eccentrics l6, H with respect to the lifting eccentrics 4, 5.

The relative displacement of the cams I5ll and eccentrics 4.5 can also be effected by displacing the eccentrics 45 on their shafts, by mechanism similar to that employed in adjusting the cams l6l'l.

As shown particularly on Fig. 8, the eccentrics I 6, I! are arranged at a level lower than eccentrics 4, 5 and more particularly to the group of these eccentrics 4, 5 located outside the furnace, on a shaft 26.

A movable stop 25 is formed by a crossbar supported by threaded arms 26 screwed in fixed nuts,

each having on its periphery teeth meshing with a worm 28, through which the position of the crossbar stop 25 can be regulated at each instant.

According to the invention and as shown on Fig. l a certain number of shafts 2 are animated with a rotational movement in the direction of the arrows F, a component of the movement of these eccentrics resulting in the lifting or raising of the bars or plates 6, I, while another component is passed in the direction of the arrow G on Fig. 1. This component results in constantly assuring the contact of the standard 29 of each frame l5 with a corresponding eccentric l6 or H.

In order to avoid excessive forces from being exerted on eccentrics l6, H the pinions 8 of certain transverse shafts 2 are driven in a diametrically opposite direction, as indicated for example at 9 on Fig. 2, thus causing the corresponding shafts 2 to rotate in the direction of the arrows H, opposite that of arrows F.

By reason of this arrangement the plates or bars 6, I constantly operate under tension, the advantage being that each bar or plate being constantly tensed, it can expand with all freedom and it may be given a slight cross section without danger of bending or sagging, which would take place if the plate operated under compression, at any movement.

This feature makes it possible to construct conveyor platforms for very small objects, the bars or plates being thinner, up to 2 mm.

Each shaft 2, rotating in the direction of the arrow H is, of course, preferably'a'rranged between two shafts rotating in the direction of the arrow F, thus assuring constant tension of each bar or plate, at any point thereof.

The function of the slide 20 (Fig. 8) which engages under the eccentrics mounted on the transverse shaft 24 exterior of the furnace is to prevent the raising of the frames l5 and the corresponding bars or plates 6, l as a result of the tangential friction which is exerted between the eccentrics l6, l1 and the vertical standard 29 of the frame Hi.

The operation is as follows:

Assuming (Fig. 8) that by reason of the relative position of sleeve I 8 on its shaft I 9, the eccentric l6 has, on said shaft IS, the same keying as the eccentrics 5 on their respective shafts 2, that is, as shown on Fig. 8, eccentric I6 is at its lowest point while all the eccentrics 5 are likewise at their lowest point.

The motor I I being set in operation it actuates the different shafts through the transmission indicated on Fig. 2, the different eccentrics assume the position indicated in broken lines on Fig. 8 from that shown in full lines, the bar or plate 6 having under a horizontal displacement or movement represented by a: and a vertical move ment represented by y, the various eccentrics being turned for an angle a. Any point of the plate or bar has come to M. The figure shows that:

X=e1 sin a y=ez (1 -cos a) .the point M will be an ellipse the horizontal axis of which will be equal to 2e and the vertical axis equal to 2e If the movement of the point M is related to the two axes 0X and CY, passing through the centre of the ellipse described by this point, the equation of the movement of point M will be given by:

. =e sin a by having e 1 represent the eccentricity of the eccentric pulley l8,while':

I Y=e (1-cos a) e representing the eccentricity of the eccentric pulleys 5.

The immediate deduction is that the path of any point of plate 6 will be an ellipse the horizontal axis of which is equal to 2e and the vertical axis equal to 2.e If this movement of any point of plate 6 is related to two perpendicular axes passing through the centre of the ellipse described by this point, the equation of the movement of this point will be given by:

X=e sin a and Y=e (1-c0s a) Practically, the horizontal course of an object placed on a set of plates such as those shown on Figs. 1 and 2 will be equal to 2e If, now, the keying of eccentric i6 is varied by advancing it, for example, relatively to eccentrics 5, the vertical movement of any given point of plate 6 will always be given by the following equation:

given by the product of the eccentricity e of eccentric i6 multiplied by the sine of the new angle. If b represents the advance angle of the eccentric it over eccentrics 5 the equation of the horizontal path will be given by:

The angular coemcient or slope of the tangent at any point of the path is equal to:

horizontal course=2e cos b The vertical course always remains equal to 2e and is independent of b'. The following is the result: By varying the relative staggering of eccentric IS the course of the object, that is, the rate of passage through the furnace, is varied.

Fig. 10-designates.the trajectory of the involved point when the staggering is equal to A;

of the circumference (11:55).-

The course is then e /2 and the object circulates from left to right.

Fig. 11 designates the trajectory obtained when the staggering is equal to A of the circumference (b=).

The trajectory is a straight line whose inclination over the horizontal is equal to r. the course is zero; the objects no, longer advance in the furnace.

Fig. 12 indicates the path (trajectory) obtained when the staggering is equal to of the circumference (b=).

The horizontal course of travel is equal to e /2,' but the horizontal displacement of an object placed on the bar takes place for the upper part of the trajectory, from right to left instead of from left to right as in the preceding figures. In other words, by giving the staggering b a value .greater than A of the circumference the circu lating direction of the objects is reversed in the furnace. a

Fig. 13 designates a trajectory obtained when the staggering is equal to a half circumference (b=). The trajectory coincides with that of Fig. 9, but the direction of travel is reversed. It is understood, of course, that other trajectories may be obtained.

It is to be understood that as there are two sets of bars 6 and l the trajectory of an object placed on the platform will be limited to the portion of the curve above the horizontal passing through the centre of the ellipse (this trajectory is accentuated on Figs. 9 to 14 by the small transverse lines). The result is that for a complete revolution of shafts 2 the advance of the objects in the furnace is equal to twice the above indicated course.

It is thus apparent that, by varying the staggering angle of eccentrics or cams l6 and I1, mounted on the shaft l9, it is possible to vary therate of passage in the furnace of the objects to be treated and to reverse at will the direction angle b (difference of staggering eccentrics l6 and 5) a value greater than 90.

The course of the objects may also be modified by varying the position of the stop crossbar 25 through action, on the worm 28. This stop, in fact, forms a check of the course or travel of the frames l5 integral with the bars. By giving the slot provided in frame IS a length, horizontally;

, greater than the space covered by the eccentric it the course of the plates may be restricted, as shown on Fig. 14, and it is even possible completely to check the horizontal course of the platform.

It is to be noted that with the described arrangement the tension effort on the plates ceases as soon as the rotation ceases, thus making maintenance, inspection and repairs easily possible.

The foregoing assemblance thus permits of numerous practical combinations according to the thermal problems to be solved.

Thus, for a furnace of predetermined width, the stop bar 25 may be made of a plurality of elements, with independent regulation of the advance and return movement; it is hence possible to provide in the furnace a certain number of longitudinal sections of different speeds; in the simplest case it is possible to have two sections, one at high speed on which, for example, light objects are placed, the other at slower speed on which heavier objects requiring a longer period of treatment are placed. It is thus easy, in a furnace thus constructed, to vary the number and width of the sections operating at different speeds cation of the invention, in which, for clarity, the

frames such as (15 are not shown, and shaft 24 shown only partially. The head shaft [9 carries two sleeves 3i! and M which are independent of each other and which may be of equal or of different'length. Shaft l9 is'actuated from horizontal shaft. it through-bevel gears t, 9 of shaft 2t and straight gears 32. The mechanism thus realized is such that shaft it rotates with the same speed as shafts 2.

The keying or adjustment of the sleeves 30 and Bi relative to drive shaft It may be regulated for any value so as to vary the course of the circu lating direction of the objects; for this purpose shaft is has keyed on it two gear wheels 23 and 33 which mesh respectively with two independent tangent screws, such as 22 (Fig. 16).

It is apparent that, by manipulating the worm it is possible to give the displacing or staggering angle the desired angle. The barswhich form the conveyor platform are thus subdivided into two groups, accordingly as the frame, such as it which drive them, are actuated by eccentrics keyed either on sleeve 30 or on sleeve 3|. The furnace is thus subdivided into two longitudinal sections, independent of each other, and capable of conveying the objects at variable speed and direction of circulation.

Different thermal cycles may be'obtained with the same furnace thusconstructed: assuming that the hot point of the furnace is at the right side on Fig. 15, the object may be placed on the section A, from which they pass to A, there to reach the desired temperature; having arrived at A, the objects are placed at B and they return to B' cooling progressively and giving off their heat units to objects which advance in the opposite-direction on the section AA. If the hot part of the furnace is at the centre thereof the cold objects may be charged or inserted at A and B, thus forming two rows of objects AA and B'B, which advance in opposite directions and which, in their respective cooling zones, give 01f their heat units to the adjacent r ,ow which, circulating in the oppositedirection, are being heated. In order to realize the foregoing thermal cycles it is sufficient to stagger sleeves 30 and 3| relatively for 180. The sections AA and BB may be divided into sub-sections, each with its own rate of speed. For this purpose it is sufficient to provide stop bars, such as 25, which limit the travel of the frame such as l5 and permitting diiferent and variable speeds on the sections. This simple example shows how the invention is capable of multiple combinations which can be instantly modified according to the thermal cycle to be produced.

It is, of course, possible to subdivide the platform into any desired number of sections, extending over the entire length of the furnace or only a portion thereof. The various elements may be of any desired materials and of any dimensions.

The arrangement for modifying the displacing or staggering of the eccentrics may be of any type suited to the specific case, and it is obviously possible, in each case, to modify the staggering of one or the other group of eccentrics by action either on the staggering proper of these eccentrics or on the shafts which support them,- or on transmission gears.

The invention is applied to. conveying through continuously operating furnaces objects intended to undergo heat treatment, said objects being of any dimension or constitution.

What is claimed is: a

1. In a furnace for the thermal conditioning of articles, the combination of a plurality of bars, means for inducing longitudinal movement of said bars, a plurality of shafts extending transversely of said bars and below the same, means associated with said shafts and bars for inducing vertical movement of said bars and means for rotating one or more of said shafts in a direction opposite to the rotation of other of said shafts whereby to keep said bars under tension. 2. In a furnace for the thermal conditioning of articles the combination of a plurality of bars, each provided with an actuating arm adjacent one end thereof, a cam operating said actuating arm, a plurality of transverse shafts, each carrying cams and engaging said bars, and means for actuating said transverse shafts -in a direction tocause said last named cams to maintain said actuating arm in working relation to the surface of the first named cam.

3. In a furnace for the thermal conditioning of articles, the combination of a plurality of bars, each provided with an actuating arm adjacent one end thereof, a plurality of cams, each operatively arranged to move the actuating arm, a sleeve to which each cam is keyed, a shaft within the sleeve, means interconnecting the sleeve and shaft whereby the sleeve and cams may be advanced or retarded angularly in respect to said shaft, and means for driving said shaft.

4. In a furnace for the thermal conditioning of articles the combination of a-series of sections, each consisting of a plurality of bars, means for imparting longitudinal movement to the bars of each section including a shaft, a plurality of spaced sleeves carried by said shaft, a plurality of cams fast to each sleeve and engaging said bars, means connecting each sleeve and shaft for adjusting the angular relation of the same, whereby the bars of onesection may be moved longitudinally to move articles through the furnace in a direction opposite to the movement of the articles occasioned by another section.

5. In a furnace for the thermal conditioning of articles, the combination of a plurality of bars free at one end, means associated with shafts extending transversely of the bars and frictionally engaging the same arranged at intervals throughout the length of the bars for imparting vertical motion thereto, means connected to the bars at a point remote from their free ends and operable in timed relation with the first named means for imparting horizontal movement to said bars, and means for varying relatively the timed relation between said first and second named means and thereby vary the rate of progression of articles through the furnace.

6. In a furnace for the thermal conditioning of articles, the combination of a plurality of bars free at one end, means associated with shafts extending transversely of the bars and frictionally engaging the same arranged at intervals throughout the length of the bars for imparting vertical motion thereto, means connected to the bars at a point remote from their free ends and operable in timed relation with the first named means for imparting horizontal movement to said bars and means for adjusting the second named means to vary the timed relation between the first and second named means and thereby vary the rate of progression of articles through the furnace.

'7. In a furnace for the thermal conditioning of articles the combination of a plurality of bars free at one end, means associated with shafts extending transversely of the bars and frictionally engaging the same arranged at intervals throughout the length of the bars for imparting vertical motion thereto, means connected to the bars at a point remote from their free ends and operable in timed relation with the first named means for imparting horizontal movement to said bars, and means for adjusting the first named means to vary the timed relation between the first and second named means and thereby vary the rate of progression of articles through the furnace.

8. In a furnace'for the thermal conditioning of articles, the combination of a plurality of bars free at one end, means associated with shafts extending transversely of the bars and frictionally engaging the same, arranged at intervals throughout the length of thebars for imparting vertical motion thereto, means connected to the bars at a point remote from their free ends and operable in timed relation with the first named means for imparting horizontal movement to said bars, and means for adjusting the first and second named means to vary the timed relation between said first and second named means and thereby vary the rate of progression of articles through the furnace.

9. In a furnace for the thermal conditioning of articles, the combination of a plurality of bars free at one end, means associated with shafts extending transversely of the bars and frictionally engaging the same arranged at intervals throughout the length of the bars for imparting vertical motion thereto, means connected to the bars at a point remote from their free ends and operable in timed relation with the first named means for imparting horizontal movement to said of articles, the combination'of a plurality of bars arrangedside by side in spaced relation and free at one end, means associated with shafts extending transversely of the bars and frictionally engaging the samearranged at intervals throughout the length of the bars for imparting vertical motion to alternate bars in succession, means connected to the bars at a point remote from their free ends and operable in timed relation with the first named means for imparting horizontal movement to alternate bars in succession, and means for varying relatively the timed relation between said first and second named means and thereby vary the rate of progression of iarticles through the furnace.

11. In a furnace for the thermal conditioning of articles, the combination of a plurality of bars having one end free, mechanism for inducing longitudin'al movement of said bars positively in one direction, means for imparting a vertical movement to the articles and-means frictionally engaging said bars at intervals throughout their length and tending to move them in the opposite direction. I

12. In a furnace for the thermal conditionin of articles, the combination of a plurality of bars having one end free, mechanism for inducing longitudinal movement of said bars positively in one direction located at a point remote from the free ends of said bars, means for imparting a vertical movement to the articles, means frictionally engaging said bars at intervals throughout their length tending to move said bars in the same direction, and means frictionally engaging said bars at intervals throughout their length tending to move them in annppesitedirection, thereby of said last named means tending to movesaid bars in the above named direction and other said means tending to move said bars in an opposite direction, thereby maintaining said'bars in a state of substantially uniform tension throughout their length independently of thermal conditions within the furnace.

14. In a furnace for the thermal conditioning of articles, the combination of a plurality of sections, each section comprising a series of bars, means associated with shafts extending transversely of the bars of each section and frictionally engaging the same arranged at intervals throughout the length of the bars to ixnpart'vertical movement thereto, driving means common to the bars of each section for imparting horizontal movement thereto, and means associated with the last named means and operable in timed relation to the first named means for moving the bars comprising each section at diflerent speeds.

15. In a furnace for the thermal conditioning of articles, the combination of a plurality of sections, each section comprising a series of bars, means associated with shafts extending transversely of the bars of each section and. frictionally engaging the same arranged at intervals throughout the length of the bars to impart vertical movement thereto, driving means common to the bars of each section for imparting horizontal movement thereto, and adjustable means permanently associated with the last named compris' g said sections, in the same ordifferent directio I 16. In a furnace for the thermal conditioning\ of articles, the combination of a plurality of sections, each section comprising a series of bars, means associated with shafts extending transversely of-the bars of each section and frictionally engaging .the same arranged at intervals throughout the length of the bars to impart vertical movement thereto, driving means common to the bars of both sections for imparting hori-' zontal movement thereto, and means-associated with the last named means for varying relatively the time of occurrence of the vertical and horizontal movements of the bars comprising each section and thereby vary the rate of progression means and operable in timed relation to the first named means for selectively moving the bars of articles on the bars oi. each section through the

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