Grapple assembly for excavating machines and the like

An assembly mountable on a dipper stick of a machine having a tool pivotally connected thereto and means operatively interconnecting the dipper stick and the tool for pivoting the tool relative to the dipper stick, cooperable with the tool for grappling objects, generally consisting of an arm member having a first section connectable to an underside of the dipper stick for pivotal movement about a second axis and a second section connectable to the first section for pivotal movement relative to the first arm section about a third axis, one of the arm sections having a curved bearing surface with a notch therein and the other of the arm sections having a roller biased against the bearing surface whereby the roller may be received in the notch to displaceably position the second arm section relative to the first arm section in a certain relationship, and ride on portions of the curved bearing surface upon a force in a certain direction as being applied to the second arm member causing the roller to ride out of the recess against the biasing force acting thereon; and a chain connected at one end to the second arm section and connectable at an opposite end thereof to the dipper stick.

This invention relates to an arm assembly connectable to the dipper stick of a machine having a tool pivotally connected thereto and means operatively interconnecting such dipper stick and such tool for pivoting the tool, cooperable with the tool for grappling objects between such assembly and the tool. This invention further contemplates an assembly which is operable to displace laterally out of alignment with such tool when a lateral force is applied thereto and to return into alignment with the tool upon removal of such force.

BACKGROUND OF THE INVENTION

In the prior art, there has been developed an assembly consisting of a dipper stick connectable to the boom of a machine such as an excavating machine, a tool typically a bucket, pivotally connected to the dipper stick, a cylinder assembly operatively interconnecting the dipper stick and the tool for pivoting the tool and an arm member mounted on and depending from the underside of the dipper stick, commonly referred to as a “thumb”, cooperable with the tool when the tool is pivoted toward the arm member for grappling objects such as trees, logs, large rocks and the like therebetween. Such an assembly is illustrated and described in U.S. Pat. No. 3,613,922.

For such an assembly to operate effectively in performing grappling operations, such arm member should lie in substantially the same vertical plane as the dipper stick and tool and be aligned with the tool to most effectively grapple an object between the tool and the arm member. Often, however, in the operation of such machines, lateral forces may be applied to such arm members which could have the effect of misaligning the arm member with a tool and, with the application of severe forces, possibly breaking the arm member from the dipper stick. Accordingly, it is the principal object of the present invention to provide an arm member of a grappling assembly which will withstand laterally directed impact forces, prevent breakage and restore it in proper alignment with the cooperating tool of the assembly for grappling objects.

SUMMARY OF THE INVENTION

The present invention provides an assembly mountable on the boom of a machine for grappling objects, generally consisting of a dipper stick pivotally connectable to such a boom, a tool connected to the dipper stick pivotal about an axis relative to the dipper stick, means operatively interconnecting the dipper stick and the tool for pivoting the tool about its pivot axis and an arm assembly mountable on the dipper stick and cooperable with the tool as the tool is pivoted relative to the dipper stick to grapple objects therebetween. The arm assembly generally includes an arm member having a first section connected to an underside of the dipper stick for pivotal movement about a second axis and a second section connected to the first arm section for pivotal movement relative to the first arm member about a third axis, one of the arm sections having a curved bearing surface with a notch therein and the other of the arm sections having a biased roller engaging the bearing surface whereby the roller may be received in the notch to displaceably position the second arm member relative to the first arm member and ride on portions of the curved surface when a force in a certain direction is applied to the second arm member; and a chain connectable at one end to the underside of the dipper stick and connected at another end thereof to the arm member. Objects grappled between such an arm assembly and a tool may be engaged by the arm assembly by means of an end of the arm member alone, such chain alone or a combination of the end of the arm member and the chain.

Referring toFIG. 1of the drawings, there is illustrated a front end assembly of an excavating machine which generally includes a dipper stick10, a bucket11, a fluid actuated cylinder assembly12and a grappling assembly13. Dipper stick10is pivotally connected to the free end of a boom14of the machine by means of a pinor set of pins15to permit the dipper stick to be pivoted about a substantially horizontal axis of pin or pins15. The lower end of the boom is pivotally connected to the front end of the main frame of the machine, and a fluid actuated cylinder assembly operatively interconnects the boom and the upper end of the dipper stick for pivoting the dipper stick about the axis of connecting pin or pins15. Similarly, one or more fluid actuated cylinder assemblies operatively interconnect the main frame of the machine and the boom for lifting and lowering the boom. Bucket11is pivotally connected to the free end of the dipper stick by means of a connecting pin16. Cylinder assembly12also is of a conventional construction including a pair of support links17,17, a pair of tilt links18,18and a hydraulic cylinder assembly19. Support links17,17are mounted on the side walls of the dipper stick adjacent connecting pin16, by means of connecting pins20,20and are connected at their free ends to a connecting pin21. Tilt links18,18are pivotally connected at one set of ends to connecting pin21and pivotally connected at the opposite ends thereof to bucket11at points spaced from connecting pin16, by means of a connecting pin22. Cylinder assembly19includes a cylinder member23connected at a base end thereof to a set of brackets24,24mounted on the upper side of the dipper stick by means of a connecting pin25, and a rod member26connected at its free end to connecting pin21. Cylinder assembly19may be operated to curl and uncurl bucket11about the axis of connecting pin16by extending and retracting rod member26in the conventional manner.

Arm assembly13includes an arm member30and a chain31. Arm member30further consists of an upper arm section32pivotally connected to the underside of the dipper stick and a lower arm section33pivotally connected to the upper arm section. As best shown inFIGS. 3,6aand6b, the upper arm section is provided with a cylindrical portion34and a plate portion35projecting substantially radially from cylindrical portion34. Portion34is received within a pair of depending brackets36,36depending from the underside of dipper stick10and is pivotally connected thereto by means of a connecting pin37. Mounted on the upper and lower surfaces of plate portion35are a pair of annular spacers38and39providing a connecting pin opening40having a axis41disposed perpendicular to a plane passing through the axis of cylindrical portion34. The leading, free edge of plate member35is radially displaced relative to axis41providing a bearing surface42which further is provided with a notch or recess43at the center thereof forming a substantially undulating surface including notch43having a curved bottom wall and a pair of forwardly and outwardly curved side walls merging with radially displaced bearing surface portions42aand42bon opposite sides of the notch.

Lower arm section33is of an elongated box beam construction having rectangularly configured pad44rigidly secured on the free end thereof, lying in a plane angled relative to a longitudinal centerline of the lower arm member. Pad44is intended to cooperate with bucket11for grappling objects therebetween. To facilitate such gripping action, pad44is provided with a pair of spaced knife-like projections45and46.

As best shown inFIGS. 3,6aand6b, the opposite end of the lower arm member is provided with upper and lower plate portions47and48rigidly secured on the upper and lower sides of the beam member and extending beyond the upper end of the beam member. The end portions of plate portions47and48engage spacers38and39and are connected thereto by means of a connecting pin49, thus pivotally connecting lower arm member33to upper arm section32for pivotal movement about axis41.

Referring toFIGS. 6aand6b, a plate member50is provided in the upper end of arm section33, spaced from the upper end thereof. Disposed within the upper end of arm section33is a cup-shaped member51having an end wall52displaceable longitudinally within the space between plate member50and the upper end of arm section33. Secured to the inner side of end portion52of the cup-shaped member is an elongated bolt53disposed longitudinally relative to arm section33, extending through an opening in plate member50and having a nut54threaded on the free end thereof. Disposed within member51and seated on plate member50is an annular spacer55receiving bolt53therethrough. Interposed between spacer25and end portion52of the cup-shaped member is a compressible elastomer56which functions to bias the cup-shaped member away from plate member50, restrained by engagement of nut54with the inner side of plate member50. Projecting from the outer side of end portion52of the displaceable cup-shaped member is a pair of ear portions57and58, as best seen inFIG. 3, supporting a pin59. Rotatably mounted on pin59, receivable within notch43and ridable on bearing surface portions42aand42bis a roller60having an axis of rotation lying on the longitudinal centerline of arm section33and perpendicular to it.

The biasing mechanism of arm section33, as described, functions to displaceably position roller60in notch43of bearing surface42under normal operating conditions to maintain arm section33longitudinally aligned with arm section32and correspondingly in cooperative alignment with bucket11to permit objects to be gripped between arm assembly13and the bucket. Upon application of a laterally directed force on the arm member, arm section33will be caused to angularly displace relative to arm section32, as shown inFIG. 6b, roller60to ride on a bearing surface portion42aor42b, depending on the direction of the force applied, and cause elastomer56to compress and thus exert a greater force on roller60. Upon removal of the laterally directed force on arm section33, compressed elastomer56will exert a force on roller60causing it to ride toward and be repositioned in notch43to again longitudinally align arm section33with arm section32. To enhance the camming action of bearing surface portions42aand42b, the radii of curvature of such surfaces relative to axis41may be made to increase in directions away from notch43. Such increased radial displacements of bearing surface portions42aand42bwill function to more positively cam roller60toward notch43to provide the desired alignment of the arm sections.

Mounted on the upper portion of arm section33, spaced from pad46, is a bumper70formed of an elastomer material and engageable with the underside of the dipper stick whenever the dipper stick is angularly displaced in a substantially vertical position as shown being approached inFIG. 5. As shown inFIG. 7, in the space provided between bumper70and pad46, the upper wall of arm section33is provided with an opening71adapted to be closed by a plate72. Plate72is provided with a circular opening73having a radially extending slot74. Opening73further is adapted to be closed by a retainer plate75which may be secured to plate member72by means of a set of bolts.

The function of chain31is to extend and thus limit the angular displacement of the arm member relative to the dipper stick, provide a gripping component when extended and cooperating with bucket11and collapsing when the dipper stick is angularly displaced approaching a vertical position. One end of the chain is linked to a bracket76on the underside of the dipper stick and an opposite end of the chain is secured to the free end of arm section33by passing a link of the chain through opening73when retainer plate75is removed, inserting a link of the chain in slot74as shown inFIG. 8and replacing retainer plate75to cover opening73and thus retain link in slot74. To adjust the angular displacement of the arm member relative to the dipper stick, retainer plate75only needs to be removed, another chain link be inserted in slot74and the retainer plate replaced.

It is contemplated that the front end assembly as described may be used alternatively to excavate utilizing only the bucket or grapple utilizing a combination of the bucket and the arm assembly. When the assembly is used in the excavating mode, the arm assembly is not removed from the front end assembly. The length of the arm member intentionally is formed of a sufficient length to permit it to be received within the opening of the bucket as the bucket is curled during a normal digging operation.

In the grappling mode, objects being grappled may be seized between the bucket and the pad portion of the arm assembly, the bucket and the chain in its extended condition or between the bucket and the chain and pad together.

Although the front end assembly described utilizes a bucket as in an excavating machine, it should be understood that any type of tool may be used within the scope of the invention which is functional to cooperate with the arm assembly to grapple objects therebetween. In addition to the tool constituting a bucket, it also may consist of a grapple, a rake a fork and the like.

In the use of the arm assembly to grapple an object such as a tree trunk, with the bucket in an uncurled position, the boom and dipper stick are maneuvered to cause chain31and pad portion44to engage a side of the trunk. Cylinder assembly12is then operated to curl the bucket and thus grip the tree trunk between the arm assembly and the bucket. The boom and dipper stick may then further be maneuvered to transport the gripped tree trunk to a selected location where the bucket may be uncurled to release and thus deposit the tree trunk at the selected location. In performing such operations, the length of chain31may be adjusted as previously described. In switching to a digging mode, no removal or adjustment of the arm assembly is required in that such assembly will not interfere with the normal curling and uncurling of the bucket as it performs a digging operation.

Whenever any lateral forces are imposed on the lower arm section to misalign the arm member with the bucket, the biasing mechanism in the lower arm section will function automatically to realign the lower end section with the bucket in the manner as previously described.

From the foregoing detailed description, it will be evident that there are a number of changes, adaptations, and modifications of the present invention which come within the province of those persons having ordinary skill in the art to which the aforementioned invention pertains. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.