GB2288717A

GB2288717A - Tip-up grass box for lawn mower

Info

Publication number: GB2288717A
Application number: GB9408311A
Authority: GB
Inventors: Francis Pepys Durie Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-04-27
Filing date: 1994-04-27
Publication date: 1995-11-01
Also published as: GB9408311D0

Abstract

A mechanism for demounting a grass cutting collection box 3 from a mounting on the body of a mower, comprising transporting the collection box to a position forward of the mower body and at a raised level above the ground upon which the mower stands, for tipping the collection box to discharge the contents of the collection box, and for returning the collection box to its mounting upon the mower body; said mechanism comprises: a. a first arm or arms 10 pivoted about a first point located axially offset from the collection box and pivotally connected to the collection box, b. a second arm or arms 20 pivoted about a second pivot point offset from said first pivot point and pivotally connected to the collection box at a position offset from said first arm(s), and c. means 4 by which an operator can cause pivoting of the first and second arm(s) about the first and second pivot points to cause the collection box to be carried over said first pivot point; the configuration of the arms and the positions of the pivot points and the connections of the arms to the collection box being such that the collection box is retained in a substantially horizontal orientation until it reaches a point on its travel at which it passes over said first pivot point, and then adopts an orientation at which it is adapted to discharge its contents. <IMAGE>

Description

TITLE: MECHANISM The present invention relates to a mechanism, notably to a mechanism for discharging the contents of the grass box of a mower.

BACKGROUND TO THE INVENTION: Many forms of grass cutting machines comprise a mower body housing the grass cutting mechanism, for example a cylinder cutter rotating about an horizontal axis or one or more horizontal blades rotating about a vertical axis; and the motive power unit, for example the electric or petrol motor driving the cutting mechanism through a suitable belt, gear or other means; the mower body being supported on ground engaging wheels or rollers or a combination of these. The grass cuttings are discharged from the cutting mechanism to a collection box or the like carried by the body, typically at the front or back of the mower body. For convenience, the term mower will be used to denote in general such grass cutting machines and the term collection box will be used to denote the container into which the grass cuttings are discharged.

When the collection box is full, the user has to remove the box and empty out the cuttings at a suitable location. It would be desirable to discharge the cuttings mechanically, rather than having to remove the collection box manually for every emptying operation.

I have now devised a mechanism by which the collection box of a mower can be discharged mechanically. The mechanism of the invention enables a user to discharge the grass cuttings from a comparatively elevated height onto a compost heap, into a wheelbarrow or the like without the need for manual exertion, and to discharge the cuttings forward of the mower so that the operator can monitor the discharge and accurately place the discharge where it is required. Such a mechanism simplifies emptying of the collection box, which encourages the mower operator to empty the collection box regularly which ensures that the cutting mechanism does not become clogged with cuttings overflowing back into the cutting mechanism from an over-full collection box. The cutting mechanism can thus be operated at all times efficiently, so that uniform cutting of the grass can be achieved.

SUMMARY OF THE INVENTION: Accordingly, the present invention provides a mower having a demountable grass cuttings collection box, characterised in that the mower is provided with a mechanism for demounting the collection box from the body of the mower, for transporting the collection box to a position forwardly of the mower body and at a raised level above the ground upon which the mower stands, for tipping the collection box to discharge the contents of the collection box, and for returning the collection box to its mounting upon the mower body; said mechanism comprising: a. a first arm or arms pivoted about a first point located axially offset from the collection box and pivotally connected to the collection box, the pivotal movement of the arms being adapted to demount the collection box from the mower body and to carry the collection box along an upward and forward arcuate path; b. a second arm or arms pivoted about a second pivot point offset from said first pivot point and pivotally connected to the collection box at a position offset from said first arm(s), the pivotal movement of said second arms being adapted to carry the collection box along a second arcuate path generally parallel to but below the said first arcuate path and passing over said first pivot point; and c. means by which an operator can cause pivoting of the first and second arm(s) about the first and second pivot points to cause the collection box to be carried over said first pivot point; the configuration of the arms and the positions of the pivot points and the connections of the arms to the collection box being such that the collection box is retained in a substantially horizontal orientation until it reaches a point on its travel at which it passes over said first pivot point, and then adopts an orientation at which it is adapted to discharge its contents.

For convenience the invention will be described in terms of a collection box mounted at the rear of the mower. However, by suitable modification of the design of the mechanism, the invention may also be applied to mowers having the collection box mounted at the front thereof.

Preferably, the first arm(s) are connected to or adjacent the upper leading edge of the collection box and the second arm(s) are connected to a point towards the rear underside of the collection box. The first arm(s) are preferably substantially straight so that the point of connection with the collection box follows a first arcuate path upwards and forwards until the arm passes through the vertical and then continues the arcuate path downwards from its apogee.

Typically, the first arcuate path will extend over an arc of greater than 1800. If desired, the first arm(s) can be curved or cranked to allow the configuration of the mechanism with a comparatively small vertical offset between the first and second pivot points without the first arms fouling the second pivot point.

The second arm(s) are preferably longer than the first arms so that the point of connection of the second arm(s) to the collection box follows a second arcuate path of greater radius than the first arcuate path. Typically, the first arm(s) will be from 75 to 95%, eg. about 85%, of the length of the second arm(s). Preferably, the second arms incorporate a crank or curve so that the second arm(s) can be provided with a pivot point between their ends as described below.

The first and second pivot points for the arms are offset axially and/or vertically from one another so that the first and second arcuate paths retain the connection point of the second arm(s) to the collection box rearwardly of the point of connection of the first arm(s) from the first pivot over the arc of travel of the collection box. It is preferred that the first pivot point be located above and axially forward of the second pivot point.

The optimum positions of the pivot points and the lengths of the first and second arms and the positions of their attachment to the collection box can be readily determined from a study of the geometry of the collection box and the point at which the collection box is to be caused to discharge its contents. Typically, the collection box will be mounted at the rear of the mower and will follow a path of travel upwardly and forwardly until it passes over the first pivot point, at which point it will begin to descend and the difference in the radii of the first and second arcs of travel of the connection points of the arms to the collection box will cause the point of attachment of the first arm(s) to the collection box to descend more rapidly than the point of attachment of the second arm(s) to the collection box. Effectively, the collection box moves overcentre as it passes over the first pivot point and begins to descend and rotate to discharge its contents.

As stated above, some means is provided for actuating the pivoting of the arms. Conveniently, this takes the form of a lever mechanism which can be depressed by the operator, preferably by applying foot pressure to the free end of a lever arm. The lever arm applies a pivoting force to the first or second arm(s) to cause the arms and the collection box to move. In a preferred configuration, the lever arm extends rearwardly of the mower and collection box, so that the free end is readily accessible to the operator, and is mounted upon a pivot pin or the like, preferably located towards the rear of the mower body. The lever arm preferably acts upon the first arm(s) so as to lift the loaded collection box. Due to the offset between the lever pivot point and the pivot point of the first arm(s), it will usually be preferred to form both the lever arm and the first arm(s) with a cranked portion about their pivot points and to link the free ends of the cranks. The crank on the lever member is preferably greater than that on the first arm(s) so that the first arm(s) pivot through a greater angular rotation than the lever arm. Typically, the crank on the lever arm is from 2 to 5 times the length of the crank on the first arm(s).

Surprisingly, I have found that the momentum generated by the initial movement of the collection box is sufficient to assist travel of the collection box over the apogee of its travel and that the mechanism can be configured so that the operation of the mechanism can be achieved by the application of foot pressure to the free end of the lever arm. However, where depression of the lever arm fails to achieve adequate momentum during the initial lifting of a fully loaded collection box from the position at which it is mounted in position on the mower housing (the rest position of the mechanism of the invention), it may be desired to provide some form of mechanical assist to the movement of the collection box. For example, the pivoting of the lever arm and/or the first and/or the second arms can be spring biassed, for example by a torsion spring incorporated in the pivot mounting, so that the spring assists pivoting of the arms. Alternatively, gas struts or other means can be employed to provide the mechanical assist. For example, eccentric weights can be incorporated into the pivot mounts of the various arms or carried by the arms, which are located with their centre of gravity over the pivots when the mechanism of the invention is in its rest position, but which move off the pivot axis and thus provide a pivoting force to the arms when the lever arm is depressed. The mechanical assist mechanisms can be configured so that they apply a positive force locating the collection box upon the mower when the mechanism of the invention is in the rest position. If desired, the lever mechanism can incorporate a ratchet mechanism whereby the pivoting force can be applied to the first arm(s) progressively in increments.

The configuration of the lever, first and second arms, the cranks on the lever and first arms and the positions of the pivot points can be selected so that as the collection box travels over the first pivot point, the free end of the crank on the first arm(s) moves away from the pivot point of the lever arm, having moved towards that pivot during the initial pivoting of the first arm(s). For example, when the mechanism is in the rest position, the crank on the lever arm can directed upwardly, the crank on the first arm(s) being directed downwardly, the free ends of the cranks being linked by a suitable rod, bar, chain or other linkage. As a result, when the free end of the lever arm is pressed downwardly to initiate pivoting of the first arm(s), the crank on the lever arm will move anti-clockwise and the crank on the first arm(s) will move clockwise. The free end of the lever arm travels downwardly until the collection box passes over the first pivot point. The interaction of the cranks on the lever and first arms will then cause the free end of the crank on the lever arm to move clockwise and thus cause the free end of the lever arm to rise until the collection box has reached the end of its travel. The user can then depress the free end of the lever arm to cause the mechanism to reverse its travel and return the collection box to the rest position in mounting engagement with the body of the mower.

As indicated above, the momentum of the collection box generated during the initial movement from either extreme of its travel is preferably sufficient to enable the collection box to travel past the apogee of its travel without the need for spring or other assist to the operation of the mechanism by the operator. In order to achieve this, the vertical offset of the first pivot point above the level of the second pivot point is a small as is practicable having regard to the need to lift the collection box clear of the mower body. The optimal vertical offset can be readily determined by simple trial and error for any given case having regard to the geometry of the mower and its collection box and the weight of the fully loaded collection box.

The components of the mechanism of the invention can be made from any suitable material, for example steel bar or rod and can be mounted on suitable pivot pins or the like mounted on the body of the mower. Alternatively, the mechanism can be mounted on a support frame which is mounted as a unit on the mower body, thus permitting the invention to be applied to existing mowers as well as during the manufacture of new mowers.

DESCRIPTION OF THE DRAWINGS: To aid understanding of the invention, a preferred form of the lever and arms mechanism will be described by way of illustration with respect to the accompanying drawings which are diagrammatic line drawings of the mechanism in the rest position (Figure 1); with the collection box at the apogee of its travel as it passes over the first pivot point (Figure 2); and with the collection box at the full extent of its travel (Figure 3).

DESCRIPTION OF THE PREFERRED EMBODIMENT: A mower body 1, for example a conventional rotary blade mower, is carried on four wheels and/or rollers 2 and carries at its rear a grass collection box 3. A rearwardly extending lever arm 4 is mounted on a transverse pivot pin 5 located adjacent the rear of the body 1 and preferably forward of the rear wheels 2. Extending at an angle of approximately 90 from lever arm 4 is a crank arm 6.

Preferably, the crank arm 6 is mounted on the bush or other pivot mounting of lever arm 4 on pin 5 so that it pivots directly about pin 5. Preferably, a strengthening gusset 7 is formed at the elbow between the lever and crank arm 6.

As indicated above, the pivot mounting can incorporate a torsion or other spring mechanism which urges lever arm 4 to pivot anti-clockwise and thus assist lifting of the load of a full collection box. It may therefore be necessary to provide some form of latch mechanism (not shown) which engages the lever arm 4 to retain it in the rest position shown in Figure 1 against the bias of the spring. However, I have found that by suitable dimensioning of the arms and the location of the pivot points of the mechanism of the invention, such spring assist is not normally required.

A first arm 10 is connected by a pivotal connection 11 to the upper edge of the collection box 3, the other end of the arm being mounted on a pivot pin 12, which can incorporate a spring mechanism to bias the arm 10 in a clockwise pivot direction. Extending at an angle, typically of from 900 to 1200, from arm 10 is a crank arm 13, which is typically only a quarter the length of the crank arm 6 on lever arm 4. The free ends of the crank arms 6 and 13 are connected by a link arm 14 through pivotal connections 15 and 16.

A second arm 20 is connected by a pivotal connection 21 to the lower rear corner of the collection box 3. Arm 20 is pivotally mounted on pivot pin 22, which is located on the base of body 1 some distance behind and below the pivot pin 12 of the first arm 10. Preferably, the second arm 20 is formed with a 900 elbow 23 adjacent the pivot 22, and has a strengthening gusset 24 at the elbow 23, so that the arm 20 does not foul the pivot mounting 5 of the lever arm 4.

Typically, arm 20 is from 10 to 15% longer than arm 10. As with pivot mountings 5 and 12, pivot mounting 22 can incorporate a spring mechanism to bias arm 20 in a clockwise pivot direction.

As shown in Figure 1, in the rest position the collection box 3 is seated against the rear grass cutting discharge opening in the mower body 1 with arms 10 and 20 generally parallel to one another. When the free end 30 of the lever arm 4 is depressed, crank arm 6 pivots anti-clockwise causing link arm 14 to pull crank arm 13 and thus pivot arm 10 clockwise. Arm 10 lifts the collecting box upwards and forwards so that the connection point 11 between arm 10 and collection box 3 follows the first dotted arcuate path 40.

Arm 20 guides and supports the rear of the collecting box 3 so that the connection 21 between arm 20 and the collection box 3 follows the second arcuate path 50 and maintains the box 3 in a generally horizontal orientation.

As stated above, the momentum of the collection box 3 carries it through the apogee of path 40 as shown in Figure 2, at which point the free end 30 of lever arm 4 reaches the lowest point in its travel, and arms 13 and 14 and pivot connection 16 pass through a straight line configuration.

The mechanism will in effect pass through an over centre configuration and the effect of the weight of the collection box will now act to assist completion of the operation of the mechanism.

Further clockwise pivoting of arm 10 causes arm 6 to begin to pivot clockwise and thus raise the free end of the lever arm 4. By virtue of the geometry of the arms and the pivot points, further clockwise pivoting of arm 10 about pivot 12 and of arm 20 about pivot 22 causes the collection box to be lowered towards the ground and to rotate about pivot connection 21 so that it adopts the tilted orientation shown in Figure 3 to discharge its contents. The extent of the further movement of the collection box can be limited by applying pressure to the free end 30 of lever arm 4 so as to restrict further movement of the-arms or can be limited by suitable stop or stops in the path of travel of one or more of arms 4, 6, 20, 13 or 10, so that box 3 discharges its contents from a suitable height above ground, for example to enable the contents to be discharged onto the top of an existing grass heap.

If the operator depresses the free end 30 of lever arm 4 when the mechanism is in its fully forward extended position as shown in Figure 3, this will now cause the arms 10 and 20 to pivot anti-clockwise. The collection box 3 will be raised and moved rearwardly so that its momentum causes it to pass in an anti-clockwise direction through the apogee on path 40. connection point 21 will follow path 50 in an anti-clockwise direction and arm 13 will pivot anticlockwise. Again, as the collection box passes the apogee of path 40, the mechanism will pass over centre and the effect of the pivoting of the arms will again reverse to bring the collection box back into engagement with the rear grass opening on body 1 with lever arm 4 raised to its start position as shown in Figure 1.

In order to accommodate variations in the size and shape of the mower body and the collection box 3, it will usually be preferred to incorporate means for adjusting the length of the arms 10, 14 and 20, for example turnbuckle connectors or the like.

Claims

CLAIMS:

1. A mechanism for demounting a grass cutting collection box from a mounting on the body of a mower, for transporting the collection box to a position forward of the mower body and at a raised level above the ground upon which the mower stands, for tipping the collection box to discharge the contents of the collection box, and for returning the collection box to its mounting upon the mower body; said mechanism comprising: a. a first arm or arms pivoted about a first point located axially offset from the collection box and pivotally connected to the collection box, the pivotal movement of the arms being adapted to demount the collection box from the mower body and to carry the collection box along an upward and forward arcuate path; b. a second arm or arms pivoted about a second pivot point offset from said first pivot point and pivotally connected to the collection box at a position offset from said first arm(s), the pivotal movement of said second arms being adapted to carry the collection box along a second arcuate path generally parallel to but below the said first arcuate path and passing over said first pivot point; and c. means by which an operator can cause pivoting of the first and second arm(s) about the first and second pivot points to cause the collection box to be carried over said first pivot point; the configuration of the arms and the positions of the pivot points and the connections of the arms to the collection box being such that the collection box is retained in a substantially horizontal orientation until it reaches a point on its travel at which it passes over said first pivot point, and then adopts an orientation at which it is adapted to discharge its contents.

2. A mechanism as claimed in claim 1, wherein the first arm(s) are connected to or adjacent the upper leading edge of the collection box and the second arm(s) are connected to a point towards the rear underside of the collection box.

3. A mechanism as claimed in either of claims 1 or 2, wherein the point of connection of the first arm with the collection box is adapted to follow a first arcuate path upwards and forwards until the arm passes through the vertical and then continues the arcuate path downwards from its apogee.

4. A mechanism as claimed in claim 3, wherein the first arcuate path extends over an arc of greater than 1800.

5. A mechanism as claimed in any one of the preceding claims, wherein the first arm(s) are curved or cranked to allow the configuration of the mechanism with a comparatively small vertical offset between the first and second pivot points without the first arms fouling the second pivot point.

6. A mechanism as claimed in any one of the preceding claims, wherein the second arm(s) are longer than the first arms so that the point of connection of the second arm(s) to the collection box follows a second arcuate path of greater radius than the first arcuate path.

7. A mechanism as claimed in claim 6, wherein the first arm(s) are from 75 to 95% of the length of the second arm(s).

8. A mechanism as claimed in any one of the preceding claims, wherein the second arms incorporate a crank or curve and the second arm(s) pivot about the apex of that crank or curve

9. A mechanism as claimed in any one of the preceding claims, wherein the first and second pivot points for the arms are offset axially and/or vertically from one another so that the first and second arcuate paths retain the connection point of the second arm(s) to the collection box rearwardly of the point of connection of the first arm(s) from the first pivot over the arc of travel of the collection box.

10. A mechanism as claimed in claim 9, wherein the first pivot point is located above and axially forward of the second pivot point.

11. A mechanism as claimed in any one of the preceding claims, wherein the collection box is to be mounted at the rear of the mower and the configuration of the first and second arm(s) and the pivot points is such that the collection box is adapted to follow a path of travel upwardly and forwardly until it passes over the first pivot point, at which point it begins to descend and the difference in the radii of the first and second arcs of travel of the connection points of the arms to the collection box will cause the point of attachment of the first arm(s) to the collection box to descend more rapidly than the point of attachment of the second arm(s) to the collection box, whereby the collection box moves overcentre as it passes over the first pivot point and begins to descend and rotate to discharge its contents.

12. A mechanism as claimed in any one of the preceding claims, wherein the means for actuating the pivoting of the arms is provided by a lever arm mechanism whose free end can be depressed by an operator to apply a pivoting force to the first or second arm(s) to cause the arms and the collection box to move.

13. A mechanism as claimed in claim 12, wherein the lever arm extends rearwardly of the mower and collection box, so that the free end is readily accessible to the operator, and is mounted upon a pivot pin or the like located towards the rear of the mower body so that the lever arm acts upon the first arm(s) so as to lift the loaded collection box.

14. A mechanism as claimed in claim 12, wherein both the lever arm and the first arm(s) are formed with a cranked portion about their pivot points and the free ends of the cranks are linked, the length of the crank on the lever member being greater than that on the first arm(s) so that the first arm(s) pivot through a greater angular rotation than the lever arm.

15. A mechanism substantially as hereinbefore shown in and as described with respect to the accompanying drawings.

16. A mower having a demountable grass cutting collection box mounted thereon and provided with a mechanism as claimed in any one of the preceding claims for demounting and emptying the cuttings from the collection box.