Patent Application
20110217153
The present invention relates to the attachment of tools to the lift arms of a loader or other work machine.
Work machines, such as loaders, are used in many industries, such as farming and construction, and are used to perform many different jobs within each industry. For example, farmers use loaders to move soil as well as lift hay bales and other heavy items. A single machine is able to perform many different tasks by having different tools that can be releasably attached to the loader lift arms. This means that the user need not buy several machines, each dedicated to a particular task, but may use one or a few, multipurpose machines instead. This clearly has advantages in terms of cost.
However, the task of attaching and detaching tools from loaders can be difficult. The tools are typically heavy, weighing upwards of a couple of hundred pounds, and manually maneuvering them is a physically demanding job. The means of attachment itself can also be cumbersome and difficult to operate, particularly during periods of cold weather when the operator will be wearing heavy gloves.
Various arrangements have been proposed to address this problem. For example, U.S. Pat. No. 5,466,113 and U.S. Pat. No. 7,001,137 both disclose latching arrangements for locking a tool to the lift arms of a work machine.
U.S. Pat. No. 5,466,113 discloses the use of a carrier or support, pivotally coupled to the lift arms using a pin, the carrier including two pairs of brackets for receiving an elongate, horizontal locking bar that is used to attach the tool to the carrier. The locking bar can be reciprocated along a horizontal axis between a locking position and an unlocking position. Corresponding brackets on the tool can be positioned in a space between the brackets on the carrier so that in the locking position the locking bar extends through the apertures in the brackets on both the carrier and the tool, thereby securing the tool to the carrier. The elongate locking bar allows the tool to be simply detached and attached to the carrier from one side only.
U.S. Pat. No. 7,001,137 discloses a similar system to that described in U.S. Pat. No. 5,466,113, but with a hydraulic cylinder for moving the locking bar between the locked and unlocked positions.
These systems are effective and user friendly, but suffer from limited durability of the carrier when the carrier is subjected to significant loads in use.
An object of the present invention is to provide an improved carrier arrangement for attaching a tool to the lift arms of a work machine, that offers the advantages of the prior art but also provides greater durability.
In a first aspect, the invention provides a combination including a lift arm, a tool and a carrier, the carrier coupled to the lift arm and the tool for releasably attaching the tool to the lift arm, the carrier comprising: a lift arm attachment point for attachment to the lift arm; a tool attachment point for releasable attachment of the tool to the carrier; and, a contact pad, for contacting the tool in use; wherein, in use, the lift arm and contact pad lie in the same vertical plane.
The lift arm attachment point may advantageously lie in the vertical plane. The tool attachment point may also advantageously lie in the vertical plane. The tool attachment point may form a part of the contact pad.
Providing a contact pad between the carrier and tool in line with the lift arm removes any transverse bending forces on the carrier. Forces applied to the tool by the lift arm during pushing operations pass directly from the lift arm through the carrier to the tool without placing any shear stresses on the carrier. Likewise, forces applied by the tool to the carrier pass directly to the lift arms. This provides a carrier that allows the tool to be releasably attached to the lift arms, with great durability. Prior carrier arrangements of this type have been found prone to failure due to bending forces applied to the carrier during use.
In a second aspect, the invention provides a carrier for attaching a tool to a pair of lift arms of a work machine, comprising: right and left lift arm attachment points, spaced from one another in a transverse direction, for attachment to the lift arms of a work machine; a tool attachment point for releasable attachment of the tool to the carrier; right and left contact pads, for contacting the tool in use; wherein the right lift arm attachment point and right contact pad lie in a first plane perpendicular to the transverse direction and the left lift arm attachment point and left contact pad lie in a second plane perpendicular to the transverse direction.
The carrier may further comprise a fastener for releasably securing the tool to the carrier at the tool attachment point.
The carrier may include right and left tool attachment points, and the right tool attachment point may lie in the first plane and the left tool attachment point may lie in the second plane. The tool attachment points may be formed within the contact pads. The tool attachment points may comprise a recess formed in each of the contact pads for receiving a corresponding bracket on a tool. The fastener may include a bar that extends through bores formed in the contact pads.
The carrier may comprise a carrier frame and the contact pads may be welded or otherwise fixed to the carrier frame. Alternatively, the contact pads may be integral with a carrier frame. The carrier frame may comprise a pair of parallel walls and the contact pads may extend between the parallel walls.
The lift arm attachment points preferably allow for pivotal movement of the carrier relative to the lift arms about a transverse axis.
The carrier may comprise right and left pairs of upright walls, and a transverse member connecting the right and left pairs of upright walls, wherein the right contact pad is positioned between the right pair of upright walls and left contact pad is positioned between the left pair of upright walls. The right lift arm attachment point may be positioned between the right pair of upright walls and left lift arm attachment point is positioned between the left pair of upright walls.
In a third aspect the invention provides combination including a lift arm, a tool and a carrier, the carrier coupled to the lift arm and the tool for releasably attaching the tool to the lift arm, the carrier comprising: a lift arm attachment point for attachment to the lift arm; a tool attachment point for releasable attachment to the tool; and wherein, in use, the lift arm and tool attachment point lie in the same vertical plane.
In a fourth aspect, the invention provides a carrier for attaching a tool to a pair of lift arms of a work machine, comprising: right and left lift arm attachment points, spaced from one another in a transverse direction, for attachment to the lift arms of a work machine; right and left tool attachment points for releasable attachment of the tool to the carrier; wherein the right lift arm attachment point and right tool attachment points lie in a first plane perpendicular to the transverse direction and the left lift arm attachment point and left tool attachment point lie in a second plane perpendicular to the transverse direction.
In a fifth aspect, the invention provides a method of attaching a tool to a lift arm of a work machine comprising the steps of: connecting the lift arm to a carrier at a first attachment point on the carrier; and connecting the tool to the carrier at a second attachment point on the carrier such that a contact pad on the carrier abuts the tool, the lift arm and contact pad lying in the same vertical plane.
The preferred embodiment will be described in detail below with reference to the accompanying drawings wherein:
a is a rear perspective view of the carrier of
b is a front perspective view of the carrier of
c is a front view of the carrier of
The term “work machine” as used herein means any vehicle used in the agricultural, construction or forestry industries for performing heavy tasks. Example work machines are loaders and tractors.
The term “lift arm” as used herein covers any type of movable arm on a work machine to which a tool or implement can be attached. Lift arms are sometimes referred to as “booms”.
The term “tool” as used herein can mean any implement or attachment for a work machine, such as a bucket, pallet fork or bale spear.
The term “attachment point” as used herein refers to any mechanical feature that allows for attachment thereto, such as a hook, a ring, an aperture, a passageway, a lug, a bracket, a threaded bore or shaft, a recess, a shelf or shoulder.
The term “contact pad” as used herein means an element that provides an abutment surface through which force can be applied. It is not limited in size or shape and can be discontinuous. It can be designed to fit against the surface of a particular tool or tools.
Each lift arm is attached to the carrier at two points. A first lift arm attachment point 16 is provided at the lower end of the carrier and a second lift arm attachment point 17 is provided about midway up the carrier. The carrier is pivotable about a horizontal axis passing through the attachment point 16 by movement of a second hydraulic ram 15. This type of connection between lift arms and carrier is described in U.S. Pat. No. 7,001,137, the contents of which are incorporated herein by reference.
The tool, in this case a bucket 10, is attached to the carrier at two points. A hook 18 on the bucket engages a transverse bar 19 at the top of the carrier. A second attachment point 30 is provided at the bottom end of the bucket, as will be described in greater detail.
a is front perspective view of the carrier alone,
A latching mechanism 46 is provided that extends between the two pairs of parallel walls 40. The latching mechanism will be described in more detail below.
The lift arms are attached to the carrier using pin or bearing that extends through apertures 16 in the carrier walls and through a corresponding passage or aperture in the end of the lift arms 11. A 45 mm diameter steel cylindrical pin and circular apertures are used to allow the carrier and/or lift arms to pivot about the pin.
The lift arms are also connected to the carrier by a similar pinned arrangement at the attachment points 17. This arrangement allows the carrier to be tilted relative to the lift arms using a hydraulic piston, as described in U.S. Pat. No. 7,001,137.
It should be noted that each lift arm in use, defines a vertical plane of movement, parallel to the plane of the paper in
With reference to
The bucket includes four hooks 18 that engage the transverse bar 19 on the top of the carrier 12. The transverse bar is a 50 mm diameter steel rod. As shown, the hooks are symmetrically disposed on either side of each pair of upright walls 40. The bucket 10 also has two latch brackets 30, shown in
The latch brackets 30 on the bucket 10 extend into a space formed in the contact pads 43 on the lower front face of the carrier 10, as shown in
It is possible to provide symmetrically disposed tool attachment points outside of the contact pads, but having the tool attachment points within the same vertical plane as the contact pads and the lift arms is the preferred arrangement as it provides the greatest durability for a given amount material, e.g. for a given thickness of the carrier walls. Other possible variations include providing the tool attachment points in line with the lift arms but contact pads disposed, preferably symmetrically, on either side of the tool attachment points in a transverse direction.
The contact pads 43 in the embodiment
As described, within the front face of each contact pad 43 a recess 44 is formed to receive the latch brackets 30 on a tool. Each contact pad includes a bore defined by apertures 45 that align with the aperture formed in the corresponding latch bracket 30 on the tool so that when the contact pad is correctly positioned in contact with the tool, the apertures 45 in the contact pad align with the aperture in the latch bracket and the transverse locking bars of the latching mechanism 46 can pass through all of the apertures to fix the tool to the carrier.
The latching mechanism is similar to that described in U.S. Pat. No. 7,001,137 and will now be briefly described. The latching mechanism operates to attach the carrier to the tool at the tool attachment points within both contact pads and may be operated to latch and unlatch the tool from one side of the carrier. The latching mechanism comprises steel locking bars that extend through the bore in each contact pad when in a locked position. A handle 47 is attached to the locking bars to allow a user to move the locking bars between locked and unlocked positions. A long locking bar 49 extends from the handle through a first pair of upright walls 40 to the bore in the contact pad on the other pair of upright walls. A short locking bar 50, comprising a 30 mm diameter pin is attached to the handle 47 by a linking arm 48 and extends through the bore in the contact pad 43 on the first pair of upright walls. The long locking bar as shown is formed in three parts. A straight section attached to the handle 47 is joined to a dog-legged section using bolts. On the end of the dog-legged section is a 30 mm diameter pin that extends into the bore formed in the contact pad.
The long locking bar 49 includes a washer 53 stopped by a cross bolt extending through the bar. A helical spring 52 is positioned between the washer and the first set of upright walls 40 to bias the locking bars into a locked position.
The locking bars are moved to an unlocked position by a user pulling the handle against the bias of the spring. In the unlocked position, the locking bars are pulled out of engagement with the latch brackets on the bucket. The bucket can then be simply disengaged from the carrier by moving the carrier downwards and out of engagement with hooks 18. The same process can be carried out in reverse to attach and lock a tool to the carrier.
A retaining bracket 51 is provide to retain and support the long locking bar 49 in alignment with the apertures in the contact pad 43 when in the unlocked position.
The retaining bracket is formed from steel and is welded to one of the upright walls 40.
Advantageously, the locking bars can be held in an unlocked position. For example, the mechanism described in U.S. Pat. No. 7,001,1137 or U.S. Pat. No. 5,466,13, the contents of which are incorporated herein by reference, may be used.
An automated mechanism for operating the latching mechanism may be provided, as described, for example, in U.S. Pat. No. 7,001,137.
Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.
