Hydraulically actuated backhoe sliding mechanism

Abstract: A mechanical excavator provided on a tractor or other vehicle (10) and which comprises a main boom (12), which at its lower end is pivotally connected to a king post assembly (20) for movement up and down in a vertical plane, a dipper arm (13) pivotally connected to the outer end of the boom (12) for movement in a vertical plane and the dipper arm (13) carrying or being adapted to carry a bucket (15) or like tool, the king post assembly (20) providing for pivotal slewing movement of the main boom (12) about a vertical axis so that the main boom (12) can be rotated from one side to the other of the centre line of the vehicle (10), the king post assembly (20) being mounted upon a guide means (28,29) extending transversely of the centre line of the vehicle (10), the king post assembly (20) being moveable along the guide means (28,29), and fixing means (33) releasably to fix the king post assembly (20) relative to the guide means (28,29) characterised in that a fluid operated ram means (40) is connected between the king post assembly (20) and an anchor means which is adapted to be fixed relative to the guide means (28,29) whereby extension or contraction of the fluid operated ram means (40) causes movement of the king post assembly (20) along the guide means (28,29).

Description: This invention relates to a mechanical excavator herein referred to as "the kind specified", provided on a tractor or other vehicle and which comprises a main boom, which at its lower end is pivotally connected to a king post assembly for movement up and down in a vertical plane, a dipper arm pivotally connected to the outer end of the boom for movement in a vertical plane and the dipper arm carrying or being adapted to carry a bucket or like tool, the king post assembly providing for pivotal slewing movement of the main boom about a vertical axis so that the main boom can be rotated from one side to the other of the centre line of the vehicle, the king post assembly being mounted upon a guide means extending transversely of the centre line of the vehicle, the king post assembly being moveable along the guide means, and fixing means releasably to fix the king post assembly relative to the guide means. Hitherto, when it has been desired to slide the king post assembly along the guide means, this has been done either by lowering the excavator bucket to engage the ground and then slewing the main boom about said vertical axis to cause movement of the king post assembly along the guide means to a desired position, or the main boom has been slewed until it is at 90° to the axis of the vehicle and the bucket then lowered to engage the ground, and the king post assembly being caused to move along the guide means by moving the dipper arm relative to the main boom (GB-959,790). Such methods of moving the king post assembly along the guide means are cumbersome and inconvenient. The use of a fluid operated ram to produce lateral movement of the king post assembly is known from United States patent US-A-4239085, where the fluid operated ram means is connected between a side shift frame assembly and a slide plate which is slidable relative to an upper implement support bracket and latchable thereto in a selected one of a plurality of positions by a latching mechanism. The use of a flexible link between two separate fluid operated ram means and a king post is disclosed in Australian patent application AU-A-5111873. US-A-3891065 discloses a frame which is moveable on a guide means and is attachable thereto by a hydraulic cylinder. An object of the present invention is to provide a mechanical excavator of the kind specified wherein at least the above mentioned problem is overcome or is reduced. According to the present invention we provide a mechanical excavator provided on a tractor or other vehicle and which comprises a main boom, which at its lower end is pivotally connected to a king post assembly for movement up and down in a vertical plane, a dipper arm pivotally connected to the outer end of the boom for movement in a vertical plane and the dipper arm carrying or being adapted to carry a bucket or like tool, the king post assembly providing for pivotal slewing movement of the main boom about a vertical axis so that the main boom can be rotated from one side to the other of the centre line of the vehicle, the king post assembly being mounted upon a guide means extending transversely of the centre line of the vehicle, the king post assembly being moveable along the guide means, whereby extension or contraction of a fluid operated ram means to a first extent causes movement of the king post assembly along the guide means to a greater extent than the first extent, and fixing means releasably to fix the king post assembly relative to the guide means wherein said fluid operated ram means is connected between the king post assembly and an anchor means which is fixed relative to the guide means, a first flexible element extending between the king post assembly and an anchorage on the guide means and a first actuating part being in engagement with the first flexible element, a second flexible element extending between the king post assembly and an anchorage on the guide means and a second actuating part being in engagement with the second flexible element characterised in that the fluid operated ram means comprises a piston rod connected at one end to said anchor means and a cylinder carrying first and second actuating parts at opposite ends of the cylinder. The first actuating part of the ram means may be connected to the king post assembly by means which permit translational relative movement between the actuating part of the ram means and the king post assembly to provide said greater extent of movement of the king post assembly. The fluid operated ram means may be connected to the king post assembly by said first flexible element which is movable by said extension or contraction of the fluid operated ram means to cause said movement of the king post assembly along the guide means. Preferably return means are provided to move the king post assembly in the opposite direction to that in which it is moved by said first flexible element. Preferably said return means comprises said second flexible element which is movable by said fluid operated ram means in the opposite direction to the first mentioned actuating part longitudinally of the guide means to move the king post assembly along the guide means in said opposite direction. Preferably a second piston rod extends from the cylinder at the opposite end thereof to said first mentioned piston rod, the second piston rod being connected to an anchor means which is adapted to be fixed relative to the guide means at the opposite end thereof to the first mentioned anchor means. The or each actuating part may comprise at least one actuating member for engaging by a flexible element. The actuating member may comprise a rotatable member. The first and/or second flexible element may have a further flexible element disposed in spaced parallel relationship therewith to provide a pair of first and/or second flexible elements respectively and the ram means being provided with a pair or pairs of first and second actuating members. The or each anchor means may be permanently fixed, or, at least during operation of the excavator may be fixed, relative to the guide means. By connecting the fluid operated ram means to the king post assembly by a flexible element which extends between the king post assembly and an anchorage on the guide means with an actuating member, movable by the fluid operated ram means, being in engagement with the flexible element, it is possible to move the king post assembly to a greater extent longitudinally of the guide means than the actuating part of the ram means and hence it is possible to move the king post assembly longitudinally of the whole extent of the guide means with a fluid operated ram means having an extent of piston rod movement which is less than the longitudinal extent of the guide means. Said anchorage may be provided at a position at or adjacent the middle of the longitudinal extent of the guide means. The or each flexible element may comprise a pivoted link chain. The ram means may be provided to extend longitudinally of the guide means at a position between the upper and lower limits of the king post assembly and in a region disposed in front of a bracket part of the king post assembly which is slidably supported by the guide means. In the broadest aspect of the invention, the guide means may comprise a frame comprising a plurality of elongated guide members arranged horizontally in vertically spaced relationship to extend at right-angles to the longitudinal axis of the vehicle and the king post assembly is carried by said guide members so as to be capable of sliding movement along the guide members with the releasable clamping means being provided for fixably clamping the king post assembly to the guide members. Preferably the fixing means of the king post assembly comprise fluid operated clamping means. The invention will now be described with reference to the accompanying drawings wherein: FIGURE 1 is a perspective view of a mechanical excavator operating from the rear of a vehicle; FIGURE 2 is a fragmentary elevation of a guide means embodying the invention for attachment to a mechanical excavator as described previously; FIGURE 3 is a section on the line 3-3 of Figure 2; FIGURE 4 is an end view looking in the direction of the arrow A in Figure 2; and FIGURE 5 is a fragmentary cross-section to an enlarged scale through a fluid operated ram of the arrangement shown in Figures 2 to 4. Figure 1 shows a vehicle 10 having at the rear a sub-frame 11 which provides a guide means upon which a mechanical excavator is mounted. The excavator comprises a main boom 12 to which a dipper arm 13 is pivotally, mounted, as shown at 14 and a bucket 15 is pivotally mounted to the dipper arm, as shown at 16. A hydraulic ram 17 is connected between the main boom 12 and the dipper arm 13 for causing pivotal movement therebetween, whilst a crowd ram 18 is pivotally connected between the dipper arm 13 and a crowd linkage 19 which is connected to the bucket 15 in conventional manner. The dipper arm 12 is carried on a king post assembly 20 comprising a boom support 21 to which the main boom 12 is pivotally connected as shown at 22 and there being a hydraulic ram 23 pivotally connected between the main boom 12 and the support 21, as shown at 24 for causing pivotal movement of the main boom 12 up and down in a vertical plane. The support 21 is connected by a king post 25 to a king post carriage 26 with a hydraulically powered rotary actuator 27 being provided for causing slewing movement of the main boom 12, about a vertical axis defined by the king post 25, relative to the carriage 26. The carriage 26 is mounted upon the transverse frame 11 which is secured to, or may be an integral part of, the rear of the vehicle 10 so as to extend at right angles to the longitudinal centre line which runs fore and aft of the vehicle. The frame 11 comprises two horizontal king post assembly guide members 28, 29 which extend between and are connected to two upright posts 30, which are conveniently made of box section with hydraulically operable telescopic legs 30a housed therein. The guide members 28, 29 are each formed from two angle section girders suitably welded at their ends to connect them to the upright posts. Accordingly, the lower king post assembly guide member 28 comprises a pair of spaced angle section elements 28 a , 28 b whilst the upper king post assembly guide member 29 comprises a pair of spaced angle section elements. The king post assembly 20 is further provided with conventional hydraulic clamping means 33. The king post assembly 20 is movable laterally of the sub-frame 11 by means not shown in Figure 1 but shown in Figures 2 to 5. Figures 2 to 5 show a sub-frame arrangement of an embodiment of the invention. The sub-frame is indicated generally at 111 and provides a guide means on which a mechanical excavator is mounted. A king post assembly is indicated generally at 120 and comprises a boom support 121 to which the main boom is pivotally connected by a pivotal connecting means 122 and there being a hydraulic ram pivotally connected between the main boom and the support 121 by a pivotal connecting means 123 causing pivotal movement of the main boom up and down a vertical plane. The support 121 is connected by king post pivot pin means 125 to a king post carriage 126 for slewing movement of the main boom about a vertical axis defined by the king post pivot pin means 125 relative to the carriage 126. The carriage 126 is mounted upon the transverse frame 111 which is secured to, or may be an integral part of, the rear of a vehicle similar to the vehicle 10 so as to extend at right-angles to the longitudinal centre line which runs fore and aft of the vehicle. The frame 111 comprises two horizontal king post assembly guide members 128, 129 which extend between and are connected to two upright posts 130, which are conveniently made so as to be of box section with hydraulically operable telescopic legs housed therein similar to legs 30 of Figure 1. The guide members 128, 129 each comprise a channel section girder having a "V"-section base 131 and spaced parallel limbs 132. At their free ends the limbs 132 have inturned flanges 133 which provide bearing surfaces for the carriage 126. At its upper end the carriage 126 has an abutment plate 134 which rests on and is adapted to slide along an outer part 135 of the upper limb of the two limbs 132 of the guide member 129 so that the weight of the king post assembly and associated boom and dipper arm etc. is carried thereby. The support 21 is slewed about the hereinbefore referred to vertical axis relative to the king post carriage 26 by means of a pair of hydraulic rams 140 each of which has a piston rod 141 which can be extended and retracted by feeding hydraulic fluid to opposite sides of a piston 142 fixed relative thereto within a cylinder 143 of the ram. Each piston rod 141 is connected at the outer end to the boom support 120 as shown at 144. Clamping means, not shown, similar to the clamping means 33 of Figure 1 are provided. In order to adjust the king post carriage longitudinally of the guide means so that it may be disposed at any desired position transversely of the rear of the tractor, a fluid operated ram means 150 is connected between the king post assembly 120 and an anchor means comprising angle brackets 151, 152 adapted to be fixed by welding to the uprights 130 of the guide means. If desired the anchor means may be permanently fixed relative to the guide means or fixed relative to the guide means at least during operation of the excavator in any other suitable manner, for example by bolting or clamping. The fluid operated ram means comprises a cylinder 153 in which a piston 154 is sealingly and slidably mounted in conventional manner. The piston 154 has a pair of opposed piston rods 155, 156 projecting therefrom and sealingly and slidably engaged with end caps 157 of the cylinder 153. The piston rods 155, 156 are connected through a rubber bushed joint 158 to an associated one of the brackets 151, 152. The cylinder 153 has a tubular extension 160, 160 a of square cross-section at each end and the tubular extensions carry a pair of opposed chain rollers 161, 161 a . A first pair of pivoted link chains 162 extend between a position 163 on the king post assembly and an anchorage 164 provided on an anchor bracket 166 which depends downwardly from the guide means 129. The chain rollers 161 engage the chains 162 so that they are entrained partially around the surface of the roller 161. A second pair of chains 167 extend from a second position 164 on the king post assembly 120 to an anchorage 168 provided on the anchor bracket 166 and are engaged by chain rollers 161 a provided at the opposite end of the cylinder 153. The roller 161 and 161 a thus provide actuating parts of the fluid pressure ram means 150. In use, hydraulic fluid is fed to a desired side of the piston 154 through one of ports 170, 171 whilst fluid is withdrawn from the opposite side of the piston 154 through the other of the ports 170, 171. This causes extension of one of the piston rods 155, 156 and retraction of the other, with consequent driving of the king post assembly longitudinally of the guide means. It will be appreciated that the king post assembly moves twice the distance moved by the actuating means and thus the king post assembly can be moved along the complete length of the guide means with an extent of piston travel of the ram assembly equal to one half of the travel of the king post assembly. The clamping means are released or engaged as necessary to permit of such adjustment. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims: A mechanical excavator provided on a tractor or other vehicle and which comprises a main boom (12), which at its lower end is pivotally connected to a king post assembly (120) for movement up and down in a vertical plane, a dipper arm (13) pivotally connected to the outer end of the boom (12) for movement in a vertical plane and the dipper arm (13) carrying or being adapted to carry a bucket (15) or like tool, the king post assembly (120) providing for pivotal slewing movement of the main boom (12) about a vertical axis so that the main boom (12) can be rotated from one side to the other of the centre line of the vehicle, the king post assembly (120) being mounted upon a guide means (111) extending transversely of the centre line of the vehicle (10), the king post assembly (120) being moveable along the guide means (111), whereby extension or contraction of a fluid operated ram means (150) to a first extent causes movement of the king post assembly (120) along the guide means (111) to a greater extent than the first extent, and fixing means (33) releasably to fix the king post assembly (120) relative to the guide means (111) wherein said fluid operated ram means (150) is connected between the king post assembly (120) and an anchor means (151, 152) which is fixed relative to the guide means (111), a first flexible element (162) extending between the king post assembly (120) and an anchorage (164) on the guide means (111) and a first actuating part (161) being in engagement with the first flexible element (162), a second flexible element (167) extending between the king post assembly (120) and an anchorage (168) on the guide means (111) and a second actuating part (161 a ) being in engagement with the second flexible element (167) characterised in that the fluid operated ram means (150) comprises a piston rod (155) connected at one end to said anchor means (151) and a cylinder (153) carrying first and second actuating parts (161, 161 a ) at opposite ends of the cylinder. An excavator according to claim 1 wherein the first actuating part (161) of the ram means (150) is connected to the king post assembly (120) by means which permit translational relative movement between the actuating part (161) of the ram means (150) and the king post assembly (120) to provide said greater extent of movement of the king post assembly (120). An excavator according to claim 1 or claim 2 wherein the fluid operated ram means (150) is connected to the king post assembly (120) by said first flexible element which is movable by said extension or contraction of the fluid operated ram means (150) to cause said movement of the king post assembly (120) along the guide means (111). An excavator according to claim 3 wherein return means are provided to move the king post assembly (120) in the opposite direction to that in which it is moved by said first flexible element (162). An excavator according to claim 4 wherein said return means comprises said second flexible element (167) which is being movable by said fluid operated ram means (150) in the opposite direction to the first mentioned actuating part (161) longitudinally of the guide means (111) to move the king post assembly (120) along the guide means (111) in said opposite direction. An excavator according to any one of claims 1 to 5 wherein a second piston rod (156) extends from the cylinder (153) at the opposite end thereof to said first mentioned piston rod (155), the second piston rod (156) being connected to an anchor means (152) which is adapted to be fixed relative to the guide means (111) at the opposite end thereof to the first mentioned anchor means (151). An excavator according to any one of claims 1 to 6 wherein the or each actuating part (161, 161 a ) comprises at least one actuating member for engaging by a flexible element (162, 167). An excavator according to any one of claims 1 to 7 wherein the first and/or second flexible element (162, 167) has a further flexible element disposed in spaced parallel relationship therewith to provide a pair of first and/or second flexible elements (162, 167) respectively and the ram means (150) being provided with a pair or pairs of first and second actuating parts (161, 161 a ). An excavator according to any one of claims 1 to 8 wherein the or each anchor means (151, 152), at least during operation of the excavator, is fixed relative to the guide means (111). An excavator according to any one of claims 1 to 9 wherein the ram means (150) is provided to extend longitudinally of the guide means (111) at a position between the upper and lower limits of the king post assembly (120) and in a region disposed in front of a bracket part of the king post assembly (120) which is slidably supported by the guide means (111).

Inventors: ALLEN WALTER ROY, ALLEN, WALTER ROY
Applicants: BAMFORD EXCAVATORS LTD, J.C. BAMFORD EXCAVATORS LIMITED
Application year: 1995
Main classification: E02F3
IPC codes: E02F3