US2369840A - Bake oven conveyer - Google Patents

Description

2 Sheets-Sheet l BAKE OVEN GONVEYER Filed March 25, 1942 J. R. NALBACH ET AL Feb. 20, 1945.

Fell 2O 1945- J. R. NALBACH x-:T AL 2,369,840

BAKE OVENy coNvEYEf;

2 sheets-smet 2 mmm U. wk k L LIL.

Filed March 23, 1942 Patented Feb. 20. 1945 UNITED STAT BAxEovENfcoNvErEn Y John lt. albach, Oak Park, and Adolph Haupt,

Chicago, Ill., assignors to Middleby-Marshall.i Oven Co., Chicago, Ill., a corporation of Illinois f Application March 23, 1942, Serial No. 435,774

6 Claims.

This invention relates. to improvements in bake oven conveyer. Y

One object of the invention is to provide an improved oven of thev traveling type provided A with tray supporting and moving means of such character that the' height of the bakingv chamber may be substantially less than theheight of conventional pendant tray traveling ovens, thereby reducing' the quantity of material, including insulation, required in the construction ofl the oven side walls and providing al` relatively smaller area to be heated.

Another object of the invention is to provide a traveling tray oven provided with pan supporting trays which are stabilized or positively supported in horizontal position throughout the path ofA travel thereof within the baking ing specication and accompanying drawings,

wherein Figure 1 is a vertical sectional view of an oven embodying the present improvements, the section being taken on line l.-I of Fig. 2;

Fig. 2 is a horizontal sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is an enlarged broken detached sectional view illustrating the tray carrying and stabilizing mechanism of the oven, the section being taken on line 3-3 of Fig. 4;

Fig. 4 is a broken plan view of the shown in Fig. 3;

Fig. 5 is a broken vertical sectional view taken on line 5-5 of Fig. 3;

Fig. 6 is a broken top plan view of a portion of a lower track and track switch;

Fig. '1 is a perspective view illustrating an mechanism The particular heating means used in supplying heat to thev oven is not particularly pertinent to the present invention, but for the purpose of illustration a iire box vI8 is shown at the rear end of the oven from which hot gases pass into a longitudinally extending centrally located duct I9 which, adjacent the forward end of the oven, communicates with a transverse header 2D. The hot gases flow from the header through heat radiating tubes 2l which at their rear ends communicate with a transverse gas receiving duct 22 from which extends an exhaust duct 23.

Above the heat radiating tubes is the baking chamber within which traveling mechanism of the oven is located. This mechanism, in the form illustrated, comprises a pair of endless chains, indicated generally by numerals 24 and 25, which are trained over a pair of sprockets 26 and 21 adjacent the forward end of the baking chamber and over a Second pair of sprockets 28 and 29 adjacent the rear end of the oven.

The sprockets 26 and 21 are mounted on a driven shaft 30 extending transversely of the oven, and in the form of the invention illustrated projects beyond the side walls thereof. A sprocket 3| is mounted on one end of the shaft 3U over which passes a drive chain 32 by means of which the shaft can be driven from vany sonrce of power such as a motor 33 shown in Fig. l. The motor may be of the reversible type or asuitable reversing clutch mechanism may be employed for driving the shaft 30 in either direction for operating the conveyer chains 24 'and 25 in the desired direction. The sprockets 28 and 29 are mounted on stub shafts 28"-, 29 respectively, as will be later described. l

The upper and lower horizontal runs of each chain are supported by upper and lower tracks 34 and 35, respectively, which are secured to the lower side walls or frame of the oven and hence support the loads imposed thereon without sagging. The pintles or pivots of the chain links ,are providedv with rollers 36 which contact the tracks for reducing friction. For supporting the pans of bakery products to be baked, trays 31 are provided, the trays being adiustablemounting for certain of the operatin" parts of the mechanism.

In .the drawings, ID generally indicates Aan oven enclosure which may be constructed in any approved manner and of any suitable materials 5 and comprises a front end wall I I. provided with a loading and unloading opening l2 (no closure therefor being shown), a rear wall I3, side walls I4, I5,`a top or roof` lli'and arba-se or iioor i1.

attached to the chains and being movable therewith. 1n Fig. 2 of the drawings the trays are shown as comprising metal frames 31a which have upwardly directed flanges 31h at the ends and rear thereof and foraminous or reticulated members 31c upon which the bake pans rest' and circulation currents can pass. I

' The trays 31 do not hang pendant frornthe traveling chains but are supported positively at their front and rear corners throughout their movements and hence are stable in all positions. Due to the fact that they are so supported they and their supporting means require less vertical space for accommodating their movements and hence the baking chamber of the improved oven may be less in height than conventional traveling ovens and the loading door l2 may also be nearer the floor, that is, it may be substantially at table height if desired, and hence the loading and unloading operations when performed by hand are much less difiicult as compared with ovens the loading doors of which are at a substantially greater distance from the floor.

Thetrays 3l are pivotally attached adjacent the rear ends thereof to the chains 24 and 25 by means of pintles or rods 3l@ which constitute the pins or pivots of certain of the chain links as illustrated in Fig. 3. The forward ends of the trays are provided with laterally projecting pins 37", having rollers thereon which generally roll on the tracks 34 and 35 whereby the trays are supported positively against tilting during the horizontal portions of the movements of the respective trays.

Mechanism is provided for stabilizing the trays during the movements from the upper to the lower as well as from the lower to the upper horizontal runs of the conveyer. This mechanism in the form illustrated comprises a pair of rotatable transfer arms 38 located forwardly of the sprockets 26, 21 and a second pair 4l of such arms located forwardly of the rear pair of sprockets 28 and 29. The arms 38 are mounted on stub shafts 38B journaled suitably in the oven wall or frame work and are provided with sprockets 40 at their outer ends over each of which passes a chain 4l to sprockets 42 mounted on the shaft 38 as shown in Fig. 2. As the shaft 30 operates, the stub shafts 38a will be rotated in timed relation therewith due to the fact that the sprockets 40 and 42 are of like diameter. The transfer arms 38 correspond in length to the diameter of the sprockets 26 and 21 and at their ends are provided with sockets or recesses 38b for receiving therein the forward roller supporting pins 31e of the respective trays.

Referring to Fig. 3, let it be assumed that the upper run of the chain is moving from right to left. Tray indicated by letter A is approaching the end of its horizontal travel but in that position is supported at its forward end by the roller pin 3le which still contacts the track 34, the end 34a of which is wider horizontally than the intermediate portion thereof. As the pin 3le of tray A reaches the end of the track 34, the tray does not tilt downwardly for the reason that an intermediate roller bearing pin 311 will then be in contact with the wide end section of the track and supports the tray against such tilting movement, and before the pin 3'!t will have moved off the end section 34a the forward pin 3Te will have moved across the gap or space between the end of section 34a and the adjacent end of a short horizontal section 34b of the upper track, and hence the tray will still. be supported positively in horizontal position. As the rear roller pin 3'ld passes off the end of the section i4a of the track to the position of tray B of Fig.

the forward roller pin 31e will have been en- `aaged by the upper end of the transfer arm 38. From the position of tray A shown in full lines in Fig. 3, the tray begins to descend, the forward end thereof in the arc described by the upper end of transfer arm 38 and the rear end of the tray in the arc of the sprocket 26, the pin Sid passing through the gap or cutout in the track above mentioned. The distance between the centers of the pins 31e and 31d of each tray is the same as the distance between the centers of the shaft 38a, and the shaft 3l).V Since the length of the arm 38 corresponds to the diameter of the sprocket 2S, 27 the tray is retained in horizontal position in its downward movement from the position of tray B to the position of tray C wherein both front and rear pins STP, rest'on the bottom track 35 which at the forward end thereof is extended. as shown in Fig. 3, to form an arcuate guide 35a against which the roller of pin 31e may contact during the descent or transfer of the tray from the upper to the lower track as described.

If it be assumed that the direction of movement is the reverse of that described above, the transfer of a tray in the position C to position B takes place somewhat similarly. Thus in the position of tray C the lower end of the arm 3d engages the pin 31e of the tray and begins to elevate it arcuately in synchronism with the arcuate elevation of the rear pin 37d which, as above described, constitutes a pivot for adjacent pairs of links of the chain and is supported by the latter. As a tray moves clockwise from nthe position C to lposition B, the arm 33 carries the pin Ele around the forward end of the track section 2511 from which it is released as the pin moves to the right and the arm continues its clockwise movement. In proceeding from position B to position A, a tray is retained in horizontal position by reason of the fact that roller pin 3l@ will not have moved to a position over the cutout or gap between the right-hand end of track section Siti and section 34a until the roller pin 3'!b will have made rolling contact with the adjacent end of the main section 34 of the track.

Since both sides of the transfer mechanism at the forward end operate similarly and operate in synchronism, the trays are positively supported in horizontal position during the transfer from one run of the conveyer to the other.

At the opposite end of the traveling mechanism the operation is the same in principle, but in providing for movement of the conveyer in both directions slightly different mechanism must be employed, since at the right end (which is assumed to be the rear end of the oven by reason of the illustrated arrangement of the trays) the front ends of the trays are moved in arcuate paths which are located between the opposite chains 24 and 25 whereas at the forward end of the oven the front end of the trays move in arcuate paths located forwardly of the carriers and horizontal portions of the tracks.

At the rear or right hand end portion of the traveling mechanism-there is provided a pair of sprockets 44 and 45 which mesh with the drains 24 and 25 respectively and which are located forwardly of the sprockets 28 and 29 a distance corresponding to the longitudinal spacing of the axes of the shafts 38 and 38. The sprockets 44 and 45 are mounted on a. transverse shaft 46 on which, at each side of the oven is mounted a transfer arm 41, corresponding to the arms 38.

The lower tracks 35 adjacent the right hand end portions thereof are provided each with a pivotally mounted section 48 secured to shafts 49 and constituting a track switch between the intermediate horizontal portion of the track 35 and an arcuate portion 35b (similar to portion 35") which extends to the rear of and in proper proximity to the sprocket 44. The switch members 48 are arranged to operate within :slots formed in the tracks 35 (see Fig. 6) which extend 'to the right to positions beneath the sprockets 28 and 29 -as illustrated in Fig. 3. Secured to eachcams 52.

Referring to Fig. 3, let it be assumed that the accantoreached the position of tray E durings'uch coun- Y traveling mechanism is moving clockwise.' Tray in position D will'move .to the right, and as the -roller pin 31' at the forward or left hand free end of the tray moves oif the right hand -end of the upper track 34, it is engaged by the'upper portion of the transfer arm 41 as illustrated by the tray in position E. The tray is thus supported at its forward end by the arms 41 at each` side of the oven and at its rear ends by the vpins 31d which are connected to the chains. As the tray moves downwardly from position E, it is retained in horizontal position by reason of the fact that the axes of the pins 31e and 31d move through similar arcs at the same rate, the sprockets 44 and 45 being driven by the respective chains 24V l and 25 at the same angular Vvelocity as that of the sprockets 28 and 29. During the descent of the tray from position E to position F, the vcurved track portions 35b retain the pins ."1e against dislodgment from the recesses 41a in ends of the arms 41 and" as the pins 31e reach the lower ends of the track sections 35h, they' contact the track switches 48, which then are in the position shownin Fig. 3, and move along the same to the ter-.clockwise movement, it assumes ahorizontal movement tothe ,left toward position D and as it moves from position E the-forward pins 31e' obtain support on the ends 34e of the, track sectionsv 34 (see Fig. 4) for supporting the forward ends of the trays as disengagement occurs between those pinsV and the transfer arms 41-. l

From the above description it will be seen that vthe trays are positively heldin horizontal rela- ,tion during the transfer ofthe same from one run of the conveyers to the other and since the means for retaining them in such relation is dis# .posed largely in the space between the planes of the upper and lower runs, the mechanism can be accommodated in a baking chamber of relatively small vertical dimensions as compared, for example, with pendant tray ovens. i

For the purpose of maintaining the chainssuitably taut and accommodating the contraction and expansion thereof, we have shown the shafts 28e, 29a and 46 journalled in sldable bearing 54.

(See Fig. '1 where the bearing at one-side only of the oven is shown.) ports one end of the shaft 46 and also the shaft 28a, is mounted in channel members 55, 56 which are sldably positioned vbetween the channelshaped gui-des 51, 58 which may be suitablyattached to the oven frame and arranged flush with the inner surface of' the furnace side wall. Brackets 59, 6U depend from the slide members 55, 56 for supporting the cam shaft 49. An abutment plate bl (see Fig. 3)A is located between the horizontal section of the track concurrently with i the movement of the pins .31d from their arcuate.

paths to the horizontal paths along the rear .or right hand portions of the lower tracks 35. During the last described portion of the movement of the tray, the switches 48 are retained in the operative positions shown in Fig. 3 by one of the dwells 52a of each cam 52 but as the rear pins 31d approach the track switches as the tray moves to the left from position F, the cams permit the counterweights to shift the switches 48 downwardly, as shown in Fig. 1, whereby the rear pins 31d of the tray can move horizontally from' posi'- tion F toward position vG of Fig. 3. Each tray as it approaches the position E as the conveyer moves clockwise is thus engaged by the transfer arms which, in cooperation with the sprockets 28 and 29, .cause the trays to be shifted from the upper to the lower runs of the chainswhile positively maintaining their horizontality.

If it be assumed that the conveyer chains are moving counterclockwise as viewed in Fig. 3,v a tray moving to the right from position G to the position F travels horizontally on the lower tracks. As it reaches the position F, the lower ends of the arms 41 will have moved into engagement with the forward pins 31e and the vcams 52 will have elevated the track switches 48 from the position shown in Fig. l to the position shownI in Fig. 3. Such shifting of the switches will not have occurred until the rear pivot pins 31d have moved beyon'd or to the right of said switches. The switches when in the position of Fig'. 3 direct the pins 31e upwardly in any arcuate path into rolling contact with the inner face of the curved track section 35h, such movement taking place simultaneously with the similar upward arcuate movement ofthe pins 31d as the latter' move around the sprockets 28, 29. When the .tray has stationaryV members 51, 58 against which a. spring 62 hears at one end while the other end of the.

spring presses against the encl of the sldable bearing structure as shown in Fig. '1. The springs 62 (one at each side'of the furnace) tend to move the movable bearings to the right as viewed in- Fig. 7 and thus retain suitable tension on the chains 24 and 25 and accommodate the contraction expansion of the chains under the influence of diierent temperatures. The curved track sections 35b also are mounted respectively on the corresponding slidable bearing structurer and hence retain their relationship with the corresponding track switch members 48 during the slight displacements of the movable bearings that may occur due to temperature changes to which the chains are subjected. Hence the slight elongation of the chains'that may occur do not disturb the properv spaced relationship of the shafts 46 with respect to shafts 28-, 29a, rior of the members 48 with respect to members 35h nor the synchronism of the operation thereof'.

In Fig. 5 a rail 63 as shown slightly spaced above thev upper rear ofthe chain 25 to restrain upward movement of the chain due to vibration or other causes, particularly where the improvements are embodied in a portable oven as in an army field oven, for example. Similar rails are provided for the upper run of the chain 24 aswell as for the lower runs of the chains, out they have been omitted from the other figures of the drawings for the purpose of avoiding confusion and obstruction of other illustrated parts.

The mechanism shown and described supports the pans of bakery products placed on the trays 31 in horizontalv positions throughout the cycle The bearing 54, which supn ovens, not only conserves the use of construction' materials but less stratification of heat in the relatively low baking chamber occurs and a more uniform 'temperature may be maintained within the oven. Likewise, the reduction in height of the oven made possible by the present improvements renders possible the installation of the oven in relatively low ceiling rooms without such r substantial building alterations as frequently are lnecessary in installing ovens of the prior type.

While we have shown and described an irnproved oven of the reversible type, that is, one in which the direction of travel may be reversed since such arrangement 'is considered desirable in some instances of use, it will be apparent that such mode of operation is not essential to the utilization of the principle of this invention, hence we do not wish to be restricted thereto nor to the specific embodiment of the invention which has been shown for the purpose of illustration.

We claim:

1. A bake oven conveyer comprising s, pair oi endless parallel chains having horizontal upper and lower runs, pairs of front and rear sprockets around which the chains pass, means for operating said chains, trays each pivotally attached at one end thereof only to said chains, horizontal tracks beneath the horizontal runs of the chains for supporting the same and for supporting the unpivoted ends of said trays during movement of the latter by the horizontal runs of the chains, transfer mechanism located adjacent one pair of sprockets for engaging the unpivoted ends of said trays for retaining the same in horizontal relation as the pivoted ends thereof are carried around said pair of sprockets in moving from one horizontal run to the other, a secondtransfer mechanism located adjacent said other pair of sprockets for engaging said unpivoted ends of said trays and moving the same arcuatelyfor retaining the trays in horizontal relation as the pivoted ends thereof are moved arcuately about said other pair of sprockets in passing from one horizontal run of the chains to the other, said second transfer mechanismcomprising arcuate track members disposed-between the upper and lower tracks and spaced from the latter, movable switches adjacent said lower tracks, and means for moving said switches into non-switching positions as the pivoted ends of said trays pass through the spaces between said arcuate track members and said lower tracks and for moving said switches into operative switching positions as said unpivoted ends of said trays approach said spaces for effecting cooperation of said switches with said second transfer mechanism in directing said unpivoted ends of the trays across said spaces.

2. A bake oven conveyer comprising a pair of endless parallel chains having horizontal upper and lower runs, pairs of front and rear sprockets around which the chains pass, means for operating said chains, trays each pivotally attached at one end'thereof only to said runs of the chains for supporting the same and for supporting the unpivoted ends of said trays during movement of the latter by the horizontal runs of the chains, transfer mechanism lochains, horizontal tracks beneath the horizontal cated forwardly of one pair of sprockets for engaging the unpivoted ends of said trays for re- -taining the same in horizontal relation as the ment of the trays about said other pair oi sprockets from one horizontal track to the other comprising arcuate track sections disposed between said upper and lower tracks and spaced at the lower ends from the respective lower tracksy track switches movable into said spaces between said lower tracks and said arcuate tracks, rotatable members each arranged to engage the unpivoted end portions of said trays and to move the same along said switches and arcuate tracks for retaining the trays in horizontal relation as the pivoted ends thereof are moved about said other pairof sprockets, and cam means for operating said track switches out of said spaces to enable the pivoted ends oi the trays to move beneath said arcuate track members along said lower horizontal tracks.

3. A bake oven conveyer comprising a pair of endless parallel chains having horizontal upper and lower runs, pairs of front and rear sprockets around which the chains pass, means for operating said chains, trays each pivotally attached at one end thereof only to said chains, horizontal tracks beneath the horizontal runs of the chains for supporting the same and for supporting the unpivoted ends of said trays during movement of the latter bythe horizontal runs of the chains, transfer mechanism located adjacent one pair of said sprockets for engaging the unpivoted ends of said trays for retaining the sam'e in horizontal relation as the pivoted ends thereof are carried around said pair oi sprockets in moving from one horizontal run to the other, and mechanism adjacent said other pair of sprockets for guiding the unpivoted ends of the trays arcuately for retaining the trays in horizontal relation as the pivoted ends thereof are moved arcuately in succession about said other sprockets from one horizontal track to the other, said mechanism comprising arcuate track sections disposed between the upper and lower horizontal tracks and being spaced from the latter to enable the pivoted ends of thetrays to pass beneath said arcuate tracks, track switches arranged for movement into said spaces to form extensions of said arcuate tracks and projecting into the plane of the lower tracks for guiding the unpivoted ends of the trays across said spaces, means for operating said switches to and from said guiding positions in timed relation with respect to the movements of the trays beneath said curved tracks, and a pair of rotatable members cooperable with said arcuate tracks and said switches for engaging unpivoted portions of said trays and moving the same along said switches and arcuate tracks in synchronism with the arcuate movement of the pivoted ends of the trays about said other sprockets.

4. An oven conveyer comprising a pair of parallel endless chains having horizontal runs, sprockets around which said chains pass, horizontal tracks beneath said horizontal runs of the chains for supporting the same, said tracks extending inwardly of the said chains, trays disposed betweensaid chains and pivotally secured at one end only of each to opposite portions of the chains, said trays having laterally projectaseaefio ing anti-friction members at the unpivoted ends thereof arranged for rolling contact with said inwardly projecting portions of said tracks for supporting the trays in horizontal 'relation during movement thereof through the ranges of the horizontal runs of the chains, mechanism located adjacent one end of the chains for retaining the trays in horizontal relation as the pivoted ends thereof pass in successionl about the adjacent sprockets, and means adjacent the other sprockets for supporting the unpivoted ends of the trays as the pivoted ends thereof move about said other sprockets, said means comprising a pair' for cooperation with said rotary members in mov.-

ing the unpivoted ends of the trays across the spaces between the-arcuate tracks and said lower tracks. Y

5. A conveyer for bake .ovens comprising a pair of endless parallel reversibly operable chains having horizontal upper and lower runs, a plurality of trays each having one end thereof only pivotally attached to opposite ends of the chains, horizontal tracks beneath the horizontal runs of said chains adapted to support the unpivoted ends of said trays in`horizontal relationv during movement thereof by the horizontal runs of the chains, rotary transfer means adjacent one end of the conveyer for retaining said trays in horizontal relation during movement thereof from one run of the conveyer to the other, arcuate track members disposed betweenvthe upper and lower tracks adjacent the other ends thereof and spaced therefro movable switches in the spaces between said arcuate track members and the lower of the said horizontal tracks at said last mentioned end of the latter and adapted to direct the unpivoted end .of each tray across the spaces between said arcuate track members and the. lower of said tracks, rotary means for engaging said unpivoted ends of the trays in succession for moving the same along said arcuate tracks and switches for retaining said unpivoted ends of the trays in horizontal augment with the respective pivoted ends thereof as the trays move from one` run of the chains` to the other at said end of the conveyer, and means for moving said switches into non-switching positions as the pivoted ends of the trays pass through said spaces and for moving said switches into operative switch positions as said unpivoted ends of said trays approach said spaces.

6, A bake oven conveyer comprising a pair of spaced apart parallel endless chains having upper and lower horizontal runs, sprockets at the ends of the conveyer around which said chains pass, trays between, the chains each pivoted at one end to opposed portions of the chains and being free at the other end, horizontal tracks disposed adjacent each of the horizontal runs of the chains for retaining said trays in horizontal relation during movement thereof by the horizontal runs of the chains, means at one end of the conveyer for engaging the free ends of the trays in succession for retaining the trays in horizontal relation as the pivoted ends thereof move about the adjacent sprockets in passing from one horizontal run of the conveyer to the other-,stabilizing means at the opposite end of the conveyer for engaging said unpivoted ends of the trays in succession for retaining the trays in horizontal relation as the pivoted ends thereof move about the adjacent sprockets, said stabilizing means comprising rotary tray engaging members, arcuate track members cooperable with said rotary members and spaced at the lower ends from said lower horizontal tracks to enable the pivoted ends of the trays to pass beneath the same in moving to and from the adjacent sprockets, track switches movable into operable positions within said spaces as the unpivoted ends of the trays approach said spaces' to provide arcuate track extensions cooperable with said transfer means for moving saidunpivoted ends of the trays across said spaces,^cam means for indexing said track switches intosaid operable positions and out of said positions in timed relation with respect to the movements of successive traysto enable the pivoted ends of the trays Y to pass through said spaces, and means for maintaining said chains taut during expansion and contraction thereof comprising longitudinally slidable means vin` which saidrotary members, said cam means, said arcuate tracks and adjacent sprockets are supported for effecting mov ment of said supported means as a unit for preserving the indexed operating relation of the same during expansion and contraction of said chains.

JOHN R. NALBACH. ADOLPH HAUPT.

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