GB2188020A - Drive system for continuous conveying system - Google Patents

Abstract

A continuous conveying system particularly for a prover for baking has a series of spaced apart supporting members 20a, 20b for baking trays extending away from one side of the drive system for the conveyor in cantilever fashion. The drive system comprises a drive chain 21 and a series of drive sprockets 35 the peripheral shapes of which are in the form of constant velocity cams. The path traversed by the supporting members comprises a first spiral path extending vertically upwardly, and a further spiral path extending vertically downwardly, with the first and further spiral paths being connected to provide the continuous conveying system. Delivery and discharge conveyors are provided for continuously loading and unloading the conveyor system. <IMAGE>

Description

SPECIFICATION Conveyor system This invention relates to a conveyor system, and more particularly, but not exclusively, a conveyor system for a prover, that is, a conveyor system for equipment for providing a process dwell time, depending on the nature of the product and the process being performed, and the remainder of this specification will be directed to the particular application in a prover. As applied to use in a prover, the invention relates to a continuous system whereby trays, pans, boards and like devices, and hereinafter generally referred to as trays, of product, such as bakery products, to be proved are continuously fed onto the conveyor system and at the same time are continuously discharged from the system at spaced locations along the path of the conveyor system.

With continuous proving of bakery products, trays of product are loaded onto a continuous conveyor system externally of the prover and are carried by the conveyor system into the prover to move therethrough to an exit therefrom, whereafter the trays are removed. The length of the conveyor system within the prover and the speed at which the conveyor moves determines the proving time.

Factors which govern the efficiency of such systems, including systems for conveying other objects, are the ease with which objects can be transferred to and from the conveyor system; the manner in which the conveyor system is driven; and the length of time any particular point on the conveyor system takes to pass a given point, or in the case of a prover to pass through the prover and therefore the proving time of the product being proved.

The primary objective of the present invention is to provide a conveying system which ensures that the lubricated components of said system will not contaminate product on parts of the system underlying other parts.

In accordance with the invention there is provided a continuous conveying system, comprising object support means driven by a drive system, wherein the support means comprises a series of spaced apart supporting means for the objects each extending away from one side of the drive system for the conveyor means in cantilever fashion.

With such a support arrangement for the tray supporting members, objects, such as product trays, on portions of the system which underly other portions, such as with the spiral arrangement defined previously, are not immediately beneath any part of the drive mechanism (chains and bearings) as would be the case with known conveying systems, and therefore are not exposed to contamination by lubricant and other contaminents gravitating from the drive mechanism for overlying portions of the conveyor system.

An objective in accordance with a further object of the invention is to provide a relatively small and simple drive means for smoothly driving conveying systems, including.

conveying systems for proving trays in baking.

Therefor, preferably the drive system comprises a chain drive and means for driving said chain, said drive means comprising at least one drive sprocket the peripheral shape of which is in the form of a constant velocity cam.

Unlike known conveyor systems, a system of the type described above in utilising a constant velocity cam which exerts a push/pull action on the chain drive avoids the need for chain tensioning and due to the continuous sliding engagement between the surfaces of the constant velocity cam and the chain drive members the "polygonal" action normally associated with chain drive sprockets is avoided and the continuity of driving engagement is not effected by any variations in chain pitch which might occur through wear.

For product which requires a relatively long proving time either a particularly long length of conveyor system within the prover, and therefore a relatively large prover, is required which occupies valuable floor area, or the conveyor speed has to be small thus reducing the quantity of product that can be proved during a particular time interval.

It is therefore an object of a further preferred form of the invention to reduce the floor area for the conveyor system and, as applied to a prover, a system whereby the quantity of product to be proved relative to the floor area occupied by the system is kept to a minimum.

Therefor, preferably the path traversed by the support means within said system comprises a first spiral path portion extending vertically upwardly, and at least one further spiral portion extending vertically downwardly, and wherein the said first and further spiral portions are connected to provide the continuous conveying system.

With the preferred conveyor path configured as described above a large portion of the length is contained within the spiral portions of its path and thus the floor area occupied by such portions is significantly less than would be occupied by an equivalent length of a non-spiral configuration. In addition the number of changes of direction at transitions between circular to linear paths is reduced to a minimum, i.e. two such changes in direction for those parts of the conveyor system on which objects reside, and which thus reduces disturbance to, and subsequent disarray of, the objects being conveyed, such as trays supporting the product to be proved and which are supported on the conveyor system.

Furthermore all the supporting structure for the conveyor system can be contained within, and between, the spirals, which once again contributes to reducing the floor area required.

An objective in accordance with a still further preferred form of the invention is to provide an arrangement whereby objects, such as proving trays supported on the conveyor means, are removed or discharged from said system efficiently and at a rate consistent with the required speed of the conveyor system.

Therefor, preferably there is provided a device for continuously collecting objects from the support means, said device comprising a discharge conveyor disposed adjacent the path of said support means, and a stationary diverting means in the path of the objects on said support means to divert the objects from said support means and onto said discharge conveyor with the linear speed of said discharge conveyor substantially corresponding to the linear speed of said support means at the point of discharge of said objects.

A discharge conveyor system of the type described above is relatively simple and reliable in operation and overcomes many of the complications of previous discharge systems.

An objective in accordance with a still further preferred form of the invention is to provide a device for delivering or discharging baking objects, such as proving, onto the support means.

Therefor, preferably there is provided a device for continuously delivering or loading objects onto the support means, said device comprising a delivery conveyor having a discharge and disposed above a point in the path of the support means.

DESCRIPTION OF THE PREFERRED EMBODI MENT One preferred embodiment of the invention, as applied to a conveyor system for a prover, will now be described with reference to the accompanying drawings, in which; Figure 1 is a schematic plan view of the conveyor system, Figure 2 is a side elevational view of the system of Figure 1, Figure 3 is a sectional view taken along line 3-3 of Figure 2, Figure 4 is an enlarged view of the section of the system shown in Figure 3, Figure 5 is a cross-sectional view taken along line 5-5 of Figure 3, Figure 6 is a cross-sectional view taken along line 6-6 of Figure 2 and showing the unloading device, and Figure 7 is a side elevational view of the unloading device of Figure 6.

Referring to Figures 1 and 2 of the draw ings, there is shown a continuous conveying system 10 for baking trays in a prover, and which is designed to continuously ioad trays external of the prover and thereafter carry the trays into the prover along a pair of interconnected spiral paths, before exiting from the prover with the trays then being continuously removed from the conveyor system.

As shown, the system comprises a main support structure 11 positioned within the co- nfines of a continuous conveying means 12, and which structure consists of a series of uprights 13 and ties 14 forming a pair of towers 15a and 15b which in turn are interconnected at their tops by additional ties 16.

The conveying means 12 is supported by support tracks around and between the towers 15a and 15b such as to provide a first spiral path portion 1 7a extending up tower 15b and than along an upper bridging portion 18 to a second spiral path portion 1 7b extending down tower 15a with the remainder of the path of the conveyor means being completed by a lower bridging portion 19. The bulk of the conveyor system, with the exception of those adjacent tray loading and unloading stations to be later described, are situated within the proving space (not shown).

As shown in more detail in Figures 3 and 4, the conveyor means 12 comprises a series of pairs of tray supporting arms 20a and 20b attached at one end by bolts 27 to the links 26 of a chain drive 21 which in turn is carried by support tracks 22 attached to, and extending around, the two towers in spiral configurations and between the towers at the top and bottoms thereof to define the continuous path of the conveyor means discussed previously.

In order to maintain the tray supporting arms 20a and 20b at a substantially horizontal orientation and extending outwardly away from the track supports, a support rail 23, attached to the main frame by brackets 28, is provided extending parallel to and spaced from the support track 22 and beneath the support arms, whilst each pair of support arms 20a and 20b are interconnected by members 24 which carry support rollers 25 at either end which in turn engage and run along the underlying support rail 23. The major portion of the length of the support arms 20a and 20b extend in cantilever fashion beyond the support rail 23 and support the baking trays. As shown in Figure 1, when moving around curved portions of the path of the conveying means, such as when moving around the spiral portions of the path, one support arm of each pair and the adjacent support arm of an adjacent pair adopt an essentially parallel relationship which changes to a generally outwardly diverging relationship when moving along the two linear portions of the path, and as movement of the arms relative to the tray supported thereon by way of sliding beneath those trays occurs only at those portions of the path where it changes direction from circular to a linear trajectory, and vice versa, at the transitions from one to the other at the top of both the spiral portions of the path between the loading and unloading stations along the path of the con veyor, that is, only twice, disturbance to the trays such as to produce possible disarray on the arms, is kept to a minimum.

As shown the track means 22 associate with the chain drive 21 are fabricated to produce upper and lower channels 29 and 30 respectively with which rollers 31 and 32 respectively cooperate. The rollers 31 and 32 are supported on axles extending through the axis of the pivot points 33 between the ends of adjacent pairs of links of the chain drive 21, and on the outside of the pairs as shown, whilst rotatable chain drive rollers 34 are retained between the ends so as to be engaged by a drive sprocket to be later described. A further roller 34a is provided midway along the length of each pair of links of the chain drive and is received within a further fabricated channel 34b directed inwardly of the conveying system and to complete the support track for the chain drive.

In this embodiment of the invention a total of five sprocket drive assemblies 35, spaced along the path of the conveyor means, are used to drive the chain drive, namely three in tower 15a, two of which are positioned near the top and bottom of the tower and one midway up the tower, and two in tower 15b at the positions shown in Figure 2. Each sprocket drive assembly 35, as shown more particularly in Figures 3, 4 and 5, comprises a support plate 36 attached to the track means, and from beneath which a geared motor 37 (electric or hydraulic) is supported and attached by bolts 38 as shown.A drive sprocket 39 in the form of a constant velocity cam is clamped between a pair of clamping members 40 and 41 which in turn a rotatably supported on the shaft 42 of the motor 37, whilst in order to rigidify the assembly a retaining bolt 43 is provided between the upper clamping member 41 and a support member 44 extending over the top face of, and spaced from, the sprocket drive and connected at either end to the uprights 13 of the frame. Additional bolt attachments 45 and 46 are provided to attach the support member 44 to pillars 47 extending upwardly from the support plate 36 on either side of the drive sprocket. In the case of electric motors, identical motors with same slip torque characteristics should be chosen for each sprocket drive assembly and all are controlled by a common variable frequency inverter.In the case of hydraulic motors, once again identical motors supplied by a common oil supply pressure, with speed being varied in the usual way, should be chosen for each sprocket drive assembly.

All drive sprockets are driven in unison and smoothly and progressively slidably engaged with the drive rollers spaced along the length of the chain drive. As the effect of the constant velocity cam form of the drive sprockets is to exert a push/pull action on the drive chain there is no need for a tensioning device for the chain, and, the drive motion is smooth and free from jerkiness which may cause undue movement of the trays on the conveyor.

In addition, the use of constant velocity cams.

as drive sprockets and resulting in a sliding contact between the sprocket and the respective drive rollers for the chain avoids the necessity to rely on the "polygonal" action associated with normal sprocket drives, and as such the sprocket can be made small in size with few teeth and its smooth driving action is uneffected by any changes in pitch, such as changes due to wear.

Referring to Figures 1, 2, 6 and 7 of the drawings, an unloading station is provided for receiving trays from the conveyor means and is positioned at the bottom of the tower 15a and adjacent the lower spiral of the downwardly spiralling path of the conveyor means.

A diverting plate 48 is angled across, and slightly above, the support arms 20a and 20b as shown in Figure 6, and as product trays following the curved path of the conveyor means at that point strike the diverting plate 48 their continuing motion is such as to direct them off the conveyor means and onto an adjacent unloading conveyor 49 comprising three continuous conveyor belts 50, 51 and 52 of progressiveiy shorter lengths to terminate just short of the curving outer trajectory of the conveyor means, and which serve to convey the trays away from the conveying means. As shown the diverting plate 18 and the conveyor belts 50, 51 and 52 are supported on a support frame comprising uprights 53 and ties 54.

Referring to Figures 1 and 2 of the drawings, a loading or delivery conveyor 55 is also provided at the bottom of tower 15b and extending between the two lower spirals of the upwardly moving spiral portion of the conveyor means, and the loading conveyor continuously desposits proving trays directly onto the lower spiral of the conveyor moving beneath its discharge end. The loading conveyor comprises a conveyor belt 56 supported on a support frame composed of uprights 57 and ties 58.

The speeds of both the loading and unloading conveyors are such that proving trays bearing product to be proved are continuously loaded on, and unloaded from, the conveying system at a speed matching that of the conveyor means within the system, and the particular nature of the loading arrangement is such that continuous loading is possible and if the loading conveyor is run at a slightly lower speed than the main conveyor there is no need for any provision to correctly space the trays on the main conveyor system. In addition, with the arrangement described the roi- lers supporting the chain drive, the support arms, and the drive rollers within the chain drive, are all accessable at the edge of the conveyor system thus allowing for ease of servicing and maintenance.

It is to be understood that the invention includes any modifications that would be envisaged by a person skilled in the art and which do not depart from the spirit of the invention, and any such modifications are to be considered within the scope of the invention.

Claims (8)

1. A continuous conveying system, comprising object support means driven by a drive a system, wherein the support means comprises a series of spaced apart supporting means for the objects each extending away from one side of the drive system for the conveyor means in cantilever fashion.

2. A continuous conveying system as claimed in claim 1, wherein the drive system comprises a drive chain and means for driving said chain, said drive means comprising at least one drive sprocket the peripheral shape of which is in the form of a constant velocity cam.

3. A continuous conveying system as claimed in claim 1 or 2, wherein the path traversed by the support means within said system comprises a first spiral path portion extending vertically upwardly, and at least one further spiral portion extending vertically downwardly, and wherein the first and further spiral portions are connected to provide the continuous conveying system.

4. A continuous conveying system as claimed in any one of claims 1 to 3, wherein there is provided a device for continuously collecting objects from the support means, said device comprising a discharge conveyor disposed adjacent the path of the support means, and a stationary diverting means in the path of the objects on the support means to divert the objects from the support means and onto said discharge conveyor with the linear speed of said discharge conveyor substantially corresponding to the linear speed of the support means at the point of discharge of said objects.

5. A continuous conveying system as claimed in any one of the preceding claims, wherein there is provided a device for continuously delivering or loading objects onto the support means, said device comprising a delivery conveyor having a discharge end disposed above a point in the path of the support means.

6. A continuous conveying system substantially as hereinbefore described with reference to the accompanying drawings.

7. A prover for baking, incorporating a continuous conveying system as claimed in any one of the preceding claims.

8. Any-novel feature or combination of features disclosed herein: