Patent Application
20190203812
The present invention relates to a tensioner bar apparatus. In particular, the invention relates to a tensioner bar apparatus for use with a tensioner arm for a drive belt. Such a drive belt may typically be found in an agricultural apparatus, such as a combine harvester or other agricultural machine.
Combine Harvesters and other agricultural machines commonly contain a number of drive systems comprising a belt or chain to transfer power from a drive source to a driven power consuming system. Such belts or chains are often provided with a means for tensioning or taking up slack in the belt or chain in the drive system.
The drive system comprises a driving wheel and a driven wheel connected by a belt. Tension in the belt is applied by an idler wheel which presses against the belt and is mounted on a tensioning arm.
The idler wheel is rotationally mounted on a first end of the tensioning arm, and the tensioning arm is pivotally mounted, at a midpoint, to the combine harvester. To the second end of the tensioning arm is connected a tensioner assembly, which applies a tensioning force.
The tensioner assembly comprises a longitudinal bar. At a first, or ‘top’ end of the bar is a clevis assembly which is connected to the second end of the tensioning arm by a clevis pin. In this prior art arrangement, the longitudinal bar is rotationally fixed to the clevis assembly such that in effect the bar and clevis assembly are a unitary item. A portion of the bar is provided with a screw thread. Fitted over this threaded portion of the bar is a spring provided with a top retainer and a bottom retainer which together keep the spring in place.
When in position on the machine, the top retainer butts up against a bracket attached to the combine harvester. The bottom retainer is kept in its position on the bar by a pair of locking nuts fitted onto the screw thread—a first locking nut for adjustment of spring compression and the second locking nut for locking the nuts in place.
When in position on the machine, the spring is effectively compressed between the bracket and the locking nuts via the action of the top and bottom retainers respectively. The action of the spring on the top retainer, and thus the bracket, acts to ‘push’ the bottom retainer, and thus the locking nuts, away from the bracket. As the locking nuts are threaded onto the longitudinal bar, this provides an axial force along the bar which in turn, through the clevis and clevis pin, produces a sustained pressure on the second end of the tensioning arm. As the tensioning arm is pivotally mounted, this produces a torque around the pivot point, such that the idler wheel, mounted on the first end of the tensioning arm, is pressed against the belt and thus provides a tensioning force on the belt.
It is occasionally necessary to adjust the tensioning assembly, either to change the spring tension or to replace worn or broken components. To do this, when the tensioning assembly is in position, it is necessary first to loosen the second locking nut. This releases the first locking nut to be rotated around, and thus move along, the threaded portion of the longitudinal bar, hence changing the axial position of the bottom retainer and thus adjusting the spring compression (and hence the force with which the spring acts against the bracket and consequently, via the longitudinal bar, tensioning arm and idler wheel, the tensioning force with which the idler wheel contacts the belt). This requires a wrench or spanner, such as an open end wrench/spanner or ratcheting wrench/spanner.
Use of such a wrench or spanner requires the involvement of an operator, and this is a job which is typically tedious and consumes an undesirable amount of time and energy. Further, machines such as a combine harvester, and indeed many other agricultural machines, are typically complex machines with many other components in close proximity to the drive system. Access to the locking nuts, where an access route is typically required to be substantially perpendicular to the axis of the longitudinal bar when a wrench is used, is therefore not always straightforward, further making the adjustment process problematic. Space is also required to allow for rotational movement of the wrench or spanner around the longitudinal bar so as to actually rotate the nut on the threaded portion. This is particularly so when the first part of the operation, namely loosening the second locking nut, may require the use of two wrenches (spanners), due to tightness of the engagement of the locking nuts—one wrench required to hold the first locking nut stationary and provide a reactive torque against the torque applied by a second wrench being used to loosen the second locking nut; this means that access is required for two wrenches. A solution to these problems would be desirable.
Accordingly there is provided in an aspect a tensioning bar assembly (111) for a tensioning assembly (101) of a drive system (60) of an agricultural machine, comprising: a longitudinal bar (102) having a longitudinal axis (2x), a top end (102t) and a bottom end (102b); an attachment device (103) attached to the top end (102t) of the longitudinal bar (102); a compression spring (4s) having first (6b) and second (6t) ends, said spring located around a portion of the longitudinal bar; and a first spring retainer (4b) for engaging with and retaining the first end (6b) of the spring; characterised in that the longitudinal bar comprises a bolt section (121), said bolt section comprising a threaded portion (102a) and an engagement head (102h), and a sleeve section (122), said sleeve section comprising an internally threaded hollow section (102c) for receipt of the bolt section (121) and further wherein the sleeve section (122) is fixedly rotationally attached to the attachment device (103).
The advantage of this tensioning assembly is that the adjustment of the tensioning assembly may be performed by using a single wrench on the engagement head 102h of the bolt section 121 in order to rotate the bolt section 121 relative to the sleeve section 122, hence altering the overall length of the bar 102. Usefully, the engagement head may not require the use of an open end wrench and may be provided with a head for engagement with a complementary socket, or alternatively a socket for engagement with a complementary head, or similar mechanical arrangement, which complementary head or socket may also be attached to a power tool of some kind, such as a pneumatic socket gun or power screwdriver. This would make the adjustment of the tensioning assembly easier and also potentially a great deal quicker, as well as greatly reducing the physical exertion required by a user in order to adjust the tensioning bar.
In an embodiment, the tensioning bar assembly further comprises a locking nut (105a) fitted on the threaded portion (102a) of the bolt section (121) of the bar (102), wherein the locking nut may be used to lock the bolt section of the bar in place in relation to the sleeve section of the bar.
A locking nut may be provided so as to assist in ‘locking’ the bolt portion of the bar axially in place relative to the sleeve portion of the bar. One skilled in the art will readily recognise the technique for this.
In an embodiment, a second spring retainer (4t) is provided for engaging with and retaining the second end (6t) of the spring.
As will be described below, when in use the tensioning bar assembly will comprise part of a tensioning assembly and will be fitted to a bracket and a tensioning arm. In some embodiments the second end of the spring 6t may directly contact the bracket, but in other embodiments the bar assembly is provided with a second spring retainer which is formed to ‘cup’ the end of the spring and this second spring retainer either butts up to, or is connected to, the bracket.
The first spring retainer is nominally kept in place longitudinally on the bar by means of the engagement head 102h of the bolt section 121 of the bar 102. When the tensioner bar assembly is in place, the first spring retainer is pushed against the engagement head by the force of the spring 4s.
In an embodiment, the first spring retainer (4b) and the engagement head (102h) may be a unitary item. It may be that the hex head of the long bolt section 121 is simply very large and so able to retain the spring.
It will be recognised that if the first spring retainer and the engagement head are a unitary item, then engagement of the spring with the first spring retainer may be more easily facilitated, as any potential perpendicular motion of the first spring retainer will be prohibited due to its engagement with the threaded portion of the bar. It will also further facilitate the adjustment of the tensioner bar assembly.
In embodiments, the engagement head (102h) at or proximate the bottom end (102b) of the bar may be any one or more of;
The ‘engagement head’ of the bolt section of the bar, at or proximate the bottom end of the longitudinal bar, has the purpose of allowing a tool to be applied to the longitudinal bar at a convenient point, and advantageously allows access to the engagement head in a longitudinal direction. Herein the bottom end of the bar may be considered to be the engagement-headed end of the bolt section. Typically, a bolt will have a hex-head engagement head, and in embodiments the bolt section will simply be a long bolt. However, it will be recognised that any shape of ‘head’ may be used or provided that allows for engagement with a tool that may be used by a user, and it is envisaged that, in particular, the use of a power tool of some description may be facilitated. The bottom end of the bar or end of the bolt section may therefore be provided with any head or socket or other shape which allows engagement with a tool, and in addition to those already listed this may include any one of a head or socket such as Security Torx, Tri-wing, Spanner, Clutch, Mortorq, Frearson, Supadriv, Polydrive, Double square, Bristol, Torq-set, One-way, Pentalobe, TP3, or TTAP head, or indeed any other suitable geometry. The bolt section of the bar will typically be manufactured with such a head or socket in place as a unitary item with the bar.
In a variant, the ‘bolt section’ of the bar may simply be a length of bar threaded along its entire length, and a suitable head may then be attached to the bottom end of the bar and locked in place with a locking nut (202h, 105c). In a further variant or this variant, a hole may be present across a diameter of the threaded bar, proximate to the bottom end, into which a pin may be inserted, and this may be engaged by a suitable tool.
In an embodiment, the attachment device at the top end of the bar is a clevis.
One skilled in the art will readily recognise and be able to easily determine alternatives to a clevis which may be used as an attachment device, such as a simple hole through the top end of the bar 102t through which a bolt may be fitted or any one of a number of alternatives of bracket, plate, or rod. However, in the art a clevis is generally used and for ease of reference herein a clevis may generally be referred to although it will of course be realised that any suitable alternative will be generally intended to be encompassed by such reference.
In an aspect, there is provided a tensioning assembly (101) for a drive system of a machine, comprising a tensioning bar assembly as described elsewhere herein, further comprising:
In an embodiment, the tensioning assembly bracket has a facing side (20f) facing towards the tensioning arm and a distal side (20d) facing away from the tensioning arm; the spring (4s) and first retainer (4b) are located on the distal side; and the second end of the spring (6t) is in direct or indirect physical contact with the distal side (20d) of the bracket such that the resultant force (Fa) acts to pull the attachment point (103p) towards the bracket.
Differing arrangements of the tensioning arms may be as described in the embodiments below:
In an embodiment, the tensioning arm (41) has a first end (41a) and a second end (41b), the tensioning device (47) being mounted proximate to the first end (41a), the clevis (or other attachment device) attachment point (103p) is proximate to the second end (41b), and the pivotal mounting (41p) of the tensioning arm is at a midpoint (41m) between the first and second ends. (
In an embodiment, the tensioning arm (41) has a first end (41a) and a second end (41b), the tensioning device (47) is mounted proximate to the first end (41a), the pivotal mounting (41p) of the tensioning arm is proximate to the second end (41b), and the clevis (or other attachment device) attachment point (103p) is at a midpoint (41m) between the first and second ends. (
In an embodiment, there may be provided a second spring retainer (4t) for engaging with and retaining the second end of the spring (6t) and the second spring retainer may further engage with the bracket.
The second end of the spring 6t may act directly against the bracket 20, or may act on a second spring retainer 4t which in turn acts upon the bracket 20. It will be recognised that the bracket may comprise a dish or annular groove which acts as a second spring retainer. The longitudinal bar may be positioned so that it passes through a hole or notch in the bracket, and/or may be positioned so that it passes through a hole or a notch in the second spring retainer. The second spring retainer may comprise a hole or notch through which the longitudinal bar passes, and may be attached by an arm so that the spring is laterally displaced from the bracket, as in
In an embodiment, the second spring retainer and the bracket may be a unitary item. In other words, the bracket may simply be formed so as to fulfil the function of the second spring retainer, or the spring retainer may be formed such as to be bolted to the machine and thus also fulfil the function of bracket.
The tensioning device may be any suitable device for pressing against the drive system of the machine.
The drive system may be a belt drive or may be a chain drive. In either case, the tensioning device may be an idler wheel, roller, or may be a simple bar. Where the drive system is a chain drive, the tensioning device may equally be an idler gear with teeth that engage the chain.
In an aspect, there is provided a drive system comprising a tensioning bar assembly or tensioning assembly as provided herein and wherein the drive system is a belt drive system or a chain drive system.
In an aspect, there is provided an agricultural machine comprising a tensioning bar assembly, a tensioning assembly, or a drive system as provided herein.
In an aspect, there is provided an agricultural machine as provided herein wherein the machine is a combine harvester. The drive system may be a drive system for a straw chopper.
The invention will now be described in more detail by reference to the attached Figures.
The drive system 60 comprises a driving wheel 61 and a driven wheel 62 connected by a belt 63. Tension in the belt is applied by a tensioning system 1. Tensioning system 1 includes an idler wheel 47 which presses against the belt and is mounted on a tensioning arm 41.
The idler wheel is rotationally mounted on a first end 41a of the tensioning arm, and the tensioning arm is pivotally mounted on a pivot 41p, at a midpoint 41m, to the combine harvester (not shown). To the second end of the tensioning arm 41b is connected a tensioner assembly 1, which applies a force Fa to the end 41b of the arm 41.
The tensioning assembly 1 comprises a longitudinal bar 2. At a first, or ‘top’ end of the bar 2t is a clevis assembly 3 which is connected to the second end of the tensioning arm 41b by a clevis pin 36 at an attachment point 3p. In this prior art arrangement, the longitudinal bar 2 is fixed to the clevis assembly 3 such that in effect the bar and clevis are a unitary item. A portion of the bar 2a is provided with a screw thread. Fitted over this threaded portion of the bar is a spring 4s, having first end 6b and second end 6t, and also a first spring retainer 4b and a second spring retainer 4t which together keep the spring in place.
When in position on the combine harvester (or machine), the second spring retainer 4t butts up against a bracket 20 which is attached, ultimately, to the combine harvester. Bracket 20 has a facing side 20f facing towards the tensioning arm 41 and a distal face 20d facing away from the tensioning arm. The first spring retainer 4b is kept in its position on the bar by a pair of locking nuts 5a, 5b fitted onto the screw thread of bar portion 2a—a first locking nut 5a for adjustment of spring compression and the second locking nut 5b for locking the nuts in place.
When in position on the machine, the spring is effectively compressed between the facing side 20f of bracket 20 and the locking nuts 5a, 5b via the action of the top and bottom (second and first) retainers 4t, 4b on ends of the spring 6t, 6b respectively. The action of the spring on the second retainer, and thus the bracket face 20f, acts to ‘push’ the first retainer, and thus the locking nuts, away from the bracket. As the locking nuts are threaded onto and thus mechanically joined to the longitudinal bar, this provides an axial force Fa along the bar which in turn, through the clevis and clevis pin, produces a sustained pulling pressure on the second end of the tensioning arm. As the tensioning arm is pivotally mounted, this produces a torque T around the pivot point 41p, such that the idler wheel 47, mounted on the first end 41a of the tensioning arm 41, is pressed against the belt and thus provides a tensioning force Ft on the belt.
There is provided a longitudinal bar 102 having a first, or top end 102t which is attached to (or unitary with) an attachment device, in this case a clevis 103 and which is formed in two parts: a sleeve portion 122 which is hollow and has a threaded internal diameter along a portion of its length; and a bolt section 121 which in this embodiment is very simply in the form of a long bolt having a hexagonal engagement head 102h and a threaded portion 102a which extends the full length of the bolt. The bolt section 121 is screwed into the sleeve portion 122 and is locked in place with a lock nut 105a which is also threaded onto the bolt portion. A tool, preferably a power tool, can clearly be applied to hex head 102h. Spring 4s with ends 6b and 6t and first and second spring retainers 4b and 4t are also fitted around the threaded portion 102a of the bolt section of the bar, at either end of the spring.
As described hereinbefore, the arrangement shown in
Clearly the skilled person will recognise that various aspects, embodiments and elements of the present application, including as illustrated in the figures, may be arranged in differing combinations, any and all of which may be considered to fall within the ambit of the inventive concept. The invention will be defined by the following claims.
This application claims the benefit of U.S. Provisional Application No. 62/612,779 filed Jan. 2, 2018, which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62612779 | Jan 2018 | US |
