GB2373305A

GB2373305A - Idle pulley belt tensioner for a flexible drive transmission system

Info

Publication number: GB2373305A
Application number: GB0202739A
Authority: GB
Inventors: Charles Leslie Glover; Leslie Smith
Original assignee: Satake Engineering Co Ltd; Satake Corp
Current assignee: Satake Engineering Co Ltd; Satake Corp
Priority date: 2001-02-06
Filing date: 2002-02-06
Publication date: 2002-09-18
Anticipated expiration: 2022-02-06
Also published as: JP2002273244A; CN1391989A; ITMI20020165A0; CH696595A5; GB0202739D0; GB2373305B; CN1259143C; ITMI20020165A1; JP4191934B2; GB0102887D0

Abstract

A flexible drive transmission system, preferably for driving the rolls of a cereal milling machine, comprises a pair of pulleys 10,11 rotatable upon generally parallel spaced axes, a flexible drive belt 12 and at least one idler pulley 19 which is preferably supported between a pair of pivotable arms 21 with and adjustment mechanism 23,24 to tension the belt. The arms 21 may be pivotable on a spigot 22 mounted on an arm 25 which is pivotable about an axis 26 normal to the axis of the pulleys 10, 11 and 19. Preferably an adjustment mechanism 27 moves an upper end of the arm 25 inwardly or outwardly to adjust the angular disposition of the axis of idler pulley 19 thus to control the tracking of the belt 12 and prevent lateral drift thereof. The spigot 22 may rotatably support a further idler pulley (28, fig 2) to minimise the wrap of the belt 12 around pulley 11.

Description

A FLEXIBLE DRIVE TRANSMISSION SYSTEM THIS INVENTION concerns flexible drive systems for machinery, and particularly, though not exclusively, relates to a drive system for a cereal milling machine adapted to reduce and grind cereal products. In such a machine known as a rollermill one or more pairs of parallel rolls which have smooth or fluted surfaces are driven in rotation side-byside and in opposite rotational directions with a small and controllable gap between the adjacent surfaces thereof which forms a milling nip through which cereal is fed to be processed by the interactive surfaces of the two rolls against the stock.

Conventionally such rolls are connected by a chain or gear drive mechanism running in an oil bath disposed at one or each axial end of the machine remote from the treatment zone.

More recently, the rolls are driven by one or more flexible belts which may be of flat or V-configuration or by one or more double-sided toothed belts which mesh with complementary surface formations on a pair of roll pulleys mounted respectively on the axes of the two rolls.

In such an arrangement one or more idler or jockey pulleys are provided to apply tension to the belt to maintain it in positive driving contact with the roll pulleys, and the or each idler or jockey pulley is mounted on an arm which is pivotally mounted on the rollermill frame with adjustment means for moving the arm about its pivot point to adjust the tension in the belt.

An object of the present invention is to provide a flexible drive transmission system of the kind referred to including controllable tracking means to prevent the belt from drifting to one side or the other in a direction parallel to the axes of the pulleys.

According to the present invention there is provided a flexible drive transmission system comprising a first pair of pulleys rotatable upon generally parallel spaced axes and wrapped by a flexible drive member, and at least one idler pulley also wrapped by the flexible drive member; characterised in that the rotational axis of the idler pulley is adjustable angularly with respect to that of at least one of said first pair of pulleys.

Preferably, said first pair of pulleys are rotated in opposite rotational directions, respectively.

The or each idler pulley may be mounted on a first arm which, at a position remote from the axis of the idler pulley, is pivotally mounted about an axis generally parallel to the axes of rotation of the first pair of pulleys, and tensioning means is connected to the arm remote from the axis of the idler pulley to cause said arm to pivot about its pivotal mount thus to adjust the driving tension of the flexible drive member.

The idler pulley may be axially and rotatably mounted on a second arm which at a position remote from the axis of the idler pulley, is pivotally mounted about an axis generally normal to the axes of rotation of the first pair of pulleys and the idler pulley, with means to adjust the pivotal position of the second arm thus to provide angular adjustment of the idler pulley axis with respect to that of at least one of the first pair of pulleys. Two or more idler pulleys may be provided.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic end elevation of a flexible belt drive system for a rollermill incorporating an angularly adjustable idler pulley mechanism made in accordance with the invention;.

Fig. 2 is a similar view of a second embodiment; Fig. 3 is a part-sectional view taken in the direction of arrow A in Fig. 1; Fig. 4 is a view similar to Figs. 1 and 2 but illustrating a third embodiment. and Fig. 5 is a schematic view similar to Fig. 2 but illustrating a fourth embodiment.

A flexible belt drive system for a rollermill comprises a first pair of pulleys 10 and 11 preferably having toothed circumferential surfaces, and a flexible drive belt 12 having complementary toothed formations on both faces thereof.

Pulley 10 is rotatable about axis 13 on which is also mounted one of a pair of grinding rolls (not shown) in a support housing 14 pivotable about axis 15 in relation to the rollermill frame, part of which is illustrated at 16.

Fixedly mounted on the rollermill frame 16 is a further housing 17 whereupon the other of the pair of grinding rolls (not shown) is rotatable upon axis 18.

As will be seen from Fig. 1 the drive belt 12 wraps the first pair of pulleys 10 and 11 such as to rotate them simultaneously in opposite rotational directions, and in a typical rollermill the housing 14 will be pivotally adjusted relative to the housing 17 to bring the rolls together or apart as required thus to set the milling gap between the roll surfaces.

An engagement mechanism is usually provided to separate the rolls widely when no stock is flowing between them.

To maintain the correct driving tension in the belt 12 a toothed idler pulley 19 also wrapped by the belt is rotatably mounted about an axis 20 in a pair of parallel arms 21 such that the idler pulley 19 rotates between them, and the arms 21 are pivotally mounted on a spigot 22 which, conventionally, is fixed to the rollermill frame and extends in a direction parallel to the axes of the pulleys 10,11 and 19.

At the opposite end of arms 21 a tensioning mechanism 23 is provided to set the belt tension, i. e. to determine the pivotal position of the arms 21 relative to the rollermill frame 16 upon which the tensioning mechanism is mounted.

The tensioning mechanism 23 includes a spring 24 to act as a shock absorber and to enable the rollermill rolls to part to accommodate any large solid objects which may pass unexpectedly through the nip.

In accordance with a first embodiment of the invention the spigot 22, instead of being mounted fixedly on the rollermill frame is mounted on a second arm 25 which is pivotally mounted at 26 on the rollermill frame about a pivotal axis extending at right-angles to the axes 13,18 and 20. At an opposite end of the arm 25 is a linear adjustment mechanism 27 thus to cause the adjacent end of the arm 25 to move inwardly and outwardly relative to the rollermill frame, i. e. pivotally about axis 26. In this manner, the angle of the axis of spigot 22 is adjusted relative to that of axes 13 and 18, which, in turn, adjusts the angle of axis 20 relative thereto. This adjustment may be used to control the tracking of drive belt 12 relative to the surfaces of pulleys 10 and 11, and thus prevent lateral drift.

Referring now to Fig. 2 in a second embodiment the belt 12 may wrap a second idler pulley 28 mounted on the arms 21. In this case the spigot 22 on second arm 25A forms the axis of rotation of the second idler pulley 28. Once again, tracking control for the belt may be achieved by angular adjustment of the spigot 22 on arm 25A, about pivotal axis 26. In this case the idler pulley is mounted directly upon the spigot 22.

Fig. 3 illustrates the manner of pivotal attachment (at 26) of the arm 25 or 25A at its lowermost end to the rollermill frame 16, and the adjustment mechanism 27 at its upper end.

Referring now to Fig. 4 it will be seen that idler pulleys 19 and 28 are mounted on arms 21A and are both wrapped by the drive belt 12, and spaced apart generally above and below the pulley 11. The arms 21A are formed to provide optimum wrap of belt 12 around pulley 11. In this case, the upper idler pulley 28 is again mounted on the spigot 22 with the lower idler pulley 19 mounted between the arms 21A adjacent the tensioning mechanism 23.

Fig. 5 illustrates a so-called two-high rollermill arrangement in which two pairs of grinding rolls are mounted respectively on axes 30,31 so that stock to be milled may flow through the gap of one pair of rolls, then that of the other.

In this case, the arrangement as shown in Fig. 2 is duplicated in superimposed relationship. The second arm 25A is mounted, as before, on pivotal axis 26, and a further second arm 25B is mounted at its upper end on the machine frame 16 on a further piovtal axis 32, and has an adjustment screw 33 at its lower end.

It is not intended to limit the invention to the examples described and illustrated herein. The principal requirement for the inventive step is that the idler pulley should be mounted on an axis which is adjustable angularly with respect to those of the main pair of pulleys 10 and 11 and preferably on a spigot attached directly to the pivoted arm.

Only a slight angular adjustment is required to ensure accurate and constant tracking of the belt on the pulleys 10 and 11, and is provided to compensate for any expected or unexpected drift of the belt to one side or the other.

Typically, the width of the pulleys 10,11 and 19 and thus that of drive belt 12 is in the order of 120mm.

Although the invention has been described in relation to a cereal milling machine, any drive mechanism incorporating a pair of pulleys and a flexible drive belt may include the means in accordance with the invention to provide angular adjustment of the axis of the idler pulley in relation to that of at least one other pulley wrapped by the drive belt. A similar mechanism may be provided for a chain drive system but is particularly applicable to a dry belt drive system.

Claims

1. A flexible drive transmission system, comprising a first pair of pulleys rotatable upon generally parallel spaced axes and wrapped by a flexible drive member, and at least one idler pulley also wrapped by the flexible drive member; characterised in that the rotational axis of the idler pulley is adjustable angularly with respect to that of at least one of said pair of pulleys.

2. A flexible drive transmission system according to Claim 1, wherein said first pair of pulleys are rotated in opposite rotational directions respectively.

3. A flexible drive transmission system according to Claim 1 or Claim 2, wherein the or each idler pulley is mounted on a first arm which, at a position remote from the axis of the idler pulley is pivotally mounted about an axis generally parallel to the axes of rotation of the first pair of pulleys, and tensioning means is connected to the arm remote from axis of the idler pulley to cause said arm to pivot about its pivotal mount thus to adjust the driving tension of the flexible drive member.

4. A flexible drive transmission system according to Claim 3, in which the or each idler pulley is axially and rotatably mounted on a second arm which, at a position remote from the idler pulley, is pivotally mounted about an axis generally normal to the axes of rotation of the first pair of pulleys and the idler pulley, with means to adjust the pivotal position of the second arm thus to provide angular adjustment of the idler pulley axis with respect to that of at least one of the first pair of pulleys.

5. A flexible drive transmission system according to any preceding claim, wherein two or more idler pulleys are provided.

6. A flexible drive transmission system according to any preceding claim, in which the or each idler pulley is mounted for rotation between a pair of parallel arms such that the idler pulley rotates between them.

7. A flexible drive transmission system according to Claim 4, wherein the second arm, at a position thereon remote from its pivotal mount, includes a linear adjustment mechanism to cause the adjacent arm of the arm to move inwardly and outwardly relative to a fixed point.

8. A flexible drive transmission system according to Claim 6, wherein the flexible drive member wraps a second idler pulley mounted for rotation between said pair of parallel arms.

9. A flexible drive transmission system according to Claim 4, wherein at least one idler pulley is rotatably mounted directly upon a spigot fixed to and extending from the second arm.

10. A flexible drive transmission system according to Claim 8, wherein said pair of parallel arms are formed to provide a support for the pair of idler pulleys the axes of rotation of which are spaced apart generally above and below at least one of said first pair of pulleys.

11. A flexible drive transmission system according to Claim 3, including a second pair of pulleys mounted beneath said first pair of pulleys, with further first and second arms, each said second arm being pivotally mounted at its lower end and having adjustment means at its upper end.

12. A flexible drive transmission system according to any preceding claim, wherein said first pair of pulleys are rotatable on axes which carry a pair of rolls in a cereal milling machine, the pulleys and rolls rotating in opposite rotational directions, the axis of one of said pulleys being adjustable relative to that of the other thus to form a milling nip between the tolls, through which cereal is fed to be processed by the interactive surfaces of the two grinding rolls.