GB2192964A

GB2192964A - Mechanism for transmitting relative angular movement between a pair of pivotally interconnected parts

Info

Publication number: GB2192964A
Application number: GB8717638A
Authority: GB
Inventors: Ian Robertson
Original assignee: MCCONNEL F W Ltd; FW McConnel Ltd
Current assignee: MCCONNEL F W Ltd; FW McConnel Ltd
Priority date: 1986-07-25
Filing date: 1987-07-24
Publication date: 1988-01-27
Anticipated expiration: 2007-07-24
Also published as: GB2192964B; GB8717634D0; GB8717638D0; GB2194423A; GB8618236D0; GB2194423B

Abstract

A mechanism for effecting relative angular movement between a pair of pivotally interconnected parts, such as an implement (10) and a supporting boom (4B), has a ram (11) fixed to the boom (4) and connected by a slave link (15) to an arm (14) fast with the implement at a position spaced from the pivotal connection of the implement with the boom. A radius arm (16) is pivoted on the boom and pivotally connected to the slave link (15) at an intermediate location on the latter spaced from the respective pivot locations on the slave link of the radius arm (16) and the ram (11). <IMAGE>

Description

SPECIFICATION Mechanism for transmitting relative angular movement between a pair of pivotally interconnected parts This invention relates to mechanism for transmitting relative angular movement between a pair of pivotally interconnected parts, being primarily for use with an implement pivotally mounted on a support such as a boom, and including power means such as a ram for effecting said movement.

In some conventional mechanisms of this general kind, the power means is a ram of which the cylinder is fixed in relation to one of the parts and the piston rod is either pivoted on a radius arm connected to the implement via a slave link, or to a common pivotal joint between such an arm and link. This arrangement has the inherent disadvantage that an increase in the speed of relative rotation between the parts tends to occur, with a resultant corresponding loss of power input, at the extremes of travel of the ram. An object of the invention is to provide a mechanism in which the aforesaid disadvantage is alleviated or avoided.

According to the present invention, a mechanism for effecting relative angular movement between a pair of pivotally interconnected parts comprises a fluid pressure-operated ram fixed relative to one of the parts, a slave link connected between the ram and a location on the other of the parts spaced from the pivotal connection between the parts, and a radius arm connected between said one part and an intermediate location of the slave link, the arrangement being such that the radius of action of the ram is maintained substantially constant during relative pivotal movement between the parts. Preferably, the radius arm is arcuate and arranged to embrace the pivotal connection between the parts when they assume one of their extreme positions of relative pivotal movement.

The invention will now be described, byway of example, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view from the rear of one form of a cutting apparatus incorporating the mechanism of the invention and mounted on a vehicle, and Figure 2 to 4 are scrap side views of the cutting apparatus of Fig. 1 in different operative positions.

Referring to the drawings, Fig. 1 illustrates an implement indicated generally at 1, in the form of a hedge cutter, mounted on the rear of a vehicle, such as a tractor, indicated generally at 2. The supplement includes a main support 3 in the form of a generally triangular frame mounted on the tractor, the frame carrying a boom 4 pivoted at 5 to an upper location on the frame. Power means, in the form of a ram 6 is pivotally connected at 7 to the frame 3 and at 8 to the boom 4 and is operable to swing the boom about its pivotal connection 5 with the frame so that the boom may assume alternative operative positions respectively at either side of the tractor, two of which positions are indicated respectively in full and broken lines in Fig. 1.The boom includes a pair of portions 4A, 4B, the latter of which carries, at its free end, a cutting head 10, illustrated as a bar cutter, which is pivotally mounted on the boom and can be swung through an arc of approximately 250 by a ram 11 which actuates the cutter through an angling mechanism, indicated generally at 12, which will now be described in more detail with reference to Figs. 2 to 4.

The bar cutter 10 is mounted on the boom portion 4B by means of a shaft 13 to which is secured an arm 14 fast for rotation with the shaft and with the cutter bar. The piston rod 11A of the ram 11 is connected to the arm 14 by a slave link 15 which is pivotally connected at its respective ends to the piston rod and arm. The slave link is connected in turn to the boom by a curved radius arm 16 pivoted to the boom portion 4B and arm 15.

The connection between the radius arm 16 and arm 15 is at an intermediate location on the latter between the respective connections of the arm 15 with the boom and piston rod.

Fig. 2 illustrates the mechanism in its retracted position with the cutter bar 10 laid back over the boom portion 4B. In Fig. 3, the mechanism is in an intermediate position with the cutter bar 10 having been moved through approximately 90" to an upright position. Fig.

4 illustrates the fully extended position of the mechanism in which the cutter bar has been pivoted through approximately 250". The curvature of the radius arm 16 is chosen so that, in the fully extended position of Fig. 4, the radius arm may embrace the adjacent end of the arm 14 thereby contributing to the large angular sweep of which the arm is capable.

The positions of the various pivotal connections between the arms 14, 15 and 16, together with the lengths of the arms are chosen such that the radius of action of the slave link 15, and thus of the pivotal connection of the rod 11 A with the link 15, remains substantially constant throughout the full rotational movement of the cutter bar, which means that the speed of rotation of the cutter arm and actuating force applied by the ram also remains substantially uniform. In particular, the separation of the radius arm and piston rod pivot locations on the slave link makes a sig nificant contribution to the advantageous geo metry of the arrangement.

1. A mechanism for effecting relative angular movement between a pair of pivotally in terconnected parts, comprising a fluid pres

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Mechanism for transmitting relative angular movement between a pair of pivotally interconnected parts This invention relates to mechanism for transmitting relative angular movement between a pair of pivotally interconnected parts, being primarily for use with an implement pivotally mounted on a support such as a boom, and including power means such as a ram for effecting said movement. In some conventional mechanisms of this general kind, the power means is a ram of which the cylinder is fixed in relation to one of the parts and the piston rod is either pivoted on a radius arm connected to the implement via a slave link, or to a common pivotal joint between such an arm and link. This arrangement has the inherent disadvantage that an increase in the speed of relative rotation between the parts tends to occur, with a resultant corresponding loss of power input, at the extremes of travel of the ram. An object of the invention is to provide a mechanism in which the aforesaid disadvantage is alleviated or avoided. According to the present invention, a mechanism for effecting relative angular movement between a pair of pivotally interconnected parts comprises a fluid pressure-operated ram fixed relative to one of the parts, a slave link connected between the ram and a location on the other of the parts spaced from the pivotal connection between the parts, and a radius arm connected between said one part and an intermediate location of the slave link, the arrangement being such that the radius of action of the ram is maintained substantially constant during relative pivotal movement between the parts. Preferably, the radius arm is arcuate and arranged to embrace the pivotal connection between the parts when they assume one of their extreme positions of relative pivotal movement. The invention will now be described, byway of example, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view from the rear of one form of a cutting apparatus incorporating the mechanism of the invention and mounted on a vehicle, and Figure 2 to 4 are scrap side views of the cutting apparatus of Fig. 1 in different operative positions. Referring to the drawings, Fig. 1 illustrates an implement indicated generally at 1, in the form of a hedge cutter, mounted on the rear of a vehicle, such as a tractor, indicated generally at 2. The supplement includes a main support 3 in the form of a generally triangular frame mounted on the tractor, the frame carrying a boom 4 pivoted at 5 to an upper location on the frame. Power means, in the form of a ram 6 is pivotally connected at 7 to the frame 3 and at 8 to the boom 4 and is operable to swing the boom about its pivotal connection 5 with the frame so that the boom may assume alternative operative positions respectively at either side of the tractor, two of which positions are indicated respectively in full and broken lines in Fig. 1.The boom includes a pair of portions 4A, 4B, the latter of which carries, at its free end, a cutting head 10, illustrated as a bar cutter, which is pivotally mounted on the boom and can be swung through an arc of approximately 250 by a ram 11 which actuates the cutter through an angling mechanism, indicated generally at 12, which will now be described in more detail with reference to Figs. 2 to 4. The bar cutter 10 is mounted on the boom portion 4B by means of a shaft 13 to which is secured an arm 14 fast for rotation with the shaft and with the cutter bar. The piston rod 11A of the ram 11 is connected to the arm 14 by a slave link 15 which is pivotally connected at its respective ends to the piston rod and arm. The slave link is connected in turn to the boom by a curved radius arm 16 pivoted to the boom portion 4B and arm 15. The connection between the radius arm 16 and arm 15 is at an intermediate location on the latter between the respective connections of the arm 15 with the boom and piston rod. Fig. 2 illustrates the mechanism in its retracted position with the cutter bar 10 laid back over the boom portion 4B. In Fig. 3, the mechanism is in an intermediate position with the cutter bar 10 having been moved through approximately 90" to an upright position. Fig. 4 illustrates the fully extended position of the mechanism in which the cutter bar has been pivoted through approximately 250". The curvature of the radius arm 16 is chosen so that, in the fully extended position of Fig. 4, the radius arm may embrace the adjacent end of the arm 14 thereby contributing to the large angular sweep of which the arm is capable. The positions of the various pivotal connections between the arms 14, 15 and 16, together with the lengths of the arms are chosen such that the radius of action of the slave link 15, and thus of the pivotal connection of the rod 11 A with the link 15, remains substantially constant throughout the full rotational movement of the cutter bar, which means that the speed of rotation of the cutter arm and actuating force applied by the ram also remains substantially uniform. In particular, the separation of the radius arm and piston rod pivot locations on the slave link makes a sig nificant contribution to the advantageous geo metry of the arrangement. CLAIMS

1. A mechanism for effecting relative angular movement between a pair of pivotally in terconnected parts, comprising a fluid pres sure-operated ram fixed relative to one of the parts, a slave link connected between the ram and a location on the other of the parts spaced from the pivotal connection between the parts, and a radius arm connected between said one part and an intermediate location of the slave link, the arrangement being such that the radius of action of the ram is maintained substantially constant during relative pivotal movement between the parts.

2. A mechanism according to Claim 1 wherein the radius arm is arcuate and arranged to embrace the pivotal connection between the parts when they assume one of their extreme positions of relative pivotal movement.

3. A mechanism according to Claim 1 or Claim 2 wherein the slave link is pivotally connected to a further arm fast for pivotal movement with the other of said parts, the pivotal connection between the slave link and further arm being at said location on said other part.

4. A mechanism according to any one of the preceding claims wherein in one extreme position of pivotal movement between the parts, said other part lies generally parallel with said one part in overlapping relationship therewith.

5. A mechanism according to Claim 3 or Claim 4 wherein the ram and said further arm are connected to respective end portions of the slave link.

6. A mechanism according to any one of the preceding claims wherein said one part is a supporting boom and the other part is a vegetation cutting device.

7. A mechanism for effecting relative angular movement between a pair of pivotally interconnected parts, substantially as hereinbefore described with reference to the accompanying drawings.