Impact resistant breaker deployment system for an excavating machine

Disclosed is an excavating machine, representatively a tracked excavator, having a boom stick portion on which both an excavating bucket and a hydraulic breaker are mounted for hydraulically driven pivotal movement between first and second limit positions. The bucket may be operated independently of the breaker for digging operations. Similarly, the breaker may be operated independently of the bucket for refusal material-breaking operations. The same excavating machine may now use the bucket and breaker in a rapid and continuous exchange to permit frequent removal of small quantities of broken refuse material with the bucket, exposing the bucket and breaker to fresh refuse material. The excavating machine disclosed incorporates an impact resistant deployment system with bifurcated and lubricated trunnion pivots and an in-line pivot restriction, or stop. The system provides a breaker assembly connection that permits quick installation and removal of the breaker, and significantly greater durability.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to a material handling apparatus and, in a preferred embodiment thereof, more particularly relates to an excavating machine, representatively a tracked excavator, having operatively attached to the stick portion of its boom a specially designed combination bucket and breaker structure which uniquely permits the excavator operator to selectively carry out either digging or refusal material breaking tasks without having to change out equipment on the stick.

BACKGROUND OF THE INVENTION

Large scale earth excavation operations are typically performed using a powered excavating apparatus, such as a tracked excavator, having an articulated, hydraulically pivotable boom structure with an elongated, pivotal outer end portion commonly referred to as a “stick.” Secured to the outer end of the stick is an excavating bucket which is hydraulically pivotable relative to the stick between “closed” and “open” positions. By pivotally manipulating the stick, with the bucket swung to a selected operating position, the excavator operator uses the bucket to forcibly dig into the ground, scoop up a quantity of dirt, and move the scooped up dirt quantity to another location, such as into the bed of an appropriately positioned dump truck.

A common occurrence during this conventional digging operation is that the bucket strikes refusal material (in excavation parlance, a material which “refuses” to be dug up) such as rock which simply cannot be broken and scooped up by the bucket. When this occurs it is typical practice to stop the digging operation, remove the bucket from the stick, and install a hydraulically operated “breaker” on the outer end of the stick in place of the removed bucket. The breaker has, on its outer end, an oscillating tool portion which rapidly hammers the refusal material in a manner breaking it up into portions which can be subsequently dug up. After the breaker has been utilized to break up the refusal material, the operator removes the breaker from the stick, replaces the breaker with the previously removed bucket, and resumes the digging operation with the bucket.

While this procedure is easy to describe, it is a difficult, laborious and time-consuming task for the operator to actually carry out due to the great size and weight of both the bucket and breaker which must be attached to and then removed from the stick, and the necessity for the operator to climb into and out of the high cab area of the excavator (often in inclement weather) to effect each bucket and breaker change-out on the stick. This sequence of bucket/breaker/bucket change-out, of course, must be laboriously repeated each time a significant refusal area is encountered in the overall digging process.

A previously utilized alternative to this single excavator sequence is to simply provide two excavators for each digging project—one excavator having a bucket attached to its boom stick, and the second excavator having a breaker attached to its boom stick. When the bucket-equipped excavator encounters refusal material during the digging process, it is simply moved away from the digging site, and the operator climbs down from the bucket-equipped excavator, walks over to and climbs up into the breaker-equipped excavator, drives the breaker-equipped excavator to the digging site, and breaks up the encountered refusal material. Reversing the process, the operator then switches to the bucket-equipped excavator and resumes the digging process to scoop up the now broken-up refusal material.

While this digging/breaking technique is easier on the operator, it is necessary to dedicate two large and costly excavators to a given digging task, thereby substantially increasing the total cost of a given excavation task. A modification of this technique is to use two operators—one to operate the bucket-equipped excavator, and one to operate the breaker-equipped excavator. This, of course, undesirably increases both the manpower and equipment cost for a given excavation project.

Another attempt to solve this problem is disclosed in U.S. Pat. No. 6,085,446 and U.S. Pat. No. 4,100,688 for an excavating machine having a motorized milling tool attached to the back of the bucket. A primary disadvantage of these devices is complexity, cost, and reliability. Another disadvantage is the weight that must be continuously carried by the bucket. The additional weight substantially reduces the carrying capacity and mobility of the bucket. Another disadvantage to the device of U.S. Pat. No. 6,085,446 is that the back of the bucket cannot be used to smooth or pad the soil, as is a well-known practice in the industry. Another disadvantage is that surface rock is not subject to an overburden pressure, so it generally fails faster under compression and impact forces than by the shearing forces of a scraping and gouging rotary drilling tool.

Another attempt to solve this problem is disclosed in U.S. Pat. No. 4,070,772 for an excavating machine having a hydraulic breaker housed inside, or on top of, the boom stick. A primary disadvantage of this device is that it is extremely complex and expensive. Another disadvantage of this device is that it cannot be retrofit to existing excavators. Another disadvantage of this device is that the size of the breaker is limited. Another disadvantage of this device is that the bucket must be fully stowed to access the breaker and vice versa, making simultaneous operation impractical.

Another attempt to solve this problem is disclosed in U.S. Pat. No. 5,689,905 for another excavating machine having a hydraulic breaker housed inside, or on top of, the boom stick. In this device, the chisel portion of the breaker is removed when not in use. A primary disadvantage of this device is that it fails to permit immediate, unassisted switching from breaker to bucket, and thus simultaneous operation is impossible. Another disadvantage of this device is that it requires manual handling of the extremely heavy chisel tool each time the operator desires to convert to a breaker or bucket operation. Another disadvantage of this device is that it is extremely complex and expensive. Another disadvantage of this device is that it cannot be retrofit to existing excavators.

A more recent attempt to solve this problem is disclosed in U.S. Pat. No. 6,751,896 for an excavating machine having a boom stick portion on which both an excavating bucket and a hydraulic breaker are mounted for hydraulically driven pivotal movement between first and second positions. A deployment system is disclosed having a bracket for closely aligned pivotal support of both the breaker and a single hydraulic cylinder on a single bracket. While this design is a marked improvement over the prior art, its primary disadvantage is that it lacks the desired level of durability at the first pivot and extension limiting (stop) mechanisms to tolerate the massive reciprocating loads of operation over time. Another disadvantage is that it is difficult to disassemble the first pivot to replace tool components. Another disadvantage is that the means for lubricating the bearing surface of the first pivot was ineffective and weakened the first pivot assembly. Another disadvantage is that it suffers durability loss from exposure of mechanical fasteners to the excavated material.

As can be readily appreciated from the foregoing, a need exists for an improved design for carrying out the requisite digging and refusal material-breaking portions of an overall excavation operation in a manner eliminating or at least substantially eliminating the above-mentioned problems, limitations and disadvantages commonly associated with conventional digging and breaking operations. It is to this need that the present invention is directed. In particular, there is a need for a new design with superior durability to the designs disclosed in U.S. Pat. No. 6,751,896.

SUMMARY OF THE INVENTION

The present invention is a marked improvement over the designs disclosed in U.S. Pat. No. 6,751,896. In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, an excavating machine, representatively a tracked excavator, is provided with a specially designed pivotable boom stick assembly that includes a boom stick having first and second excavating tools secured thereto for movement relative to the boom stick. Illustratively, the first excavating tool is an excavating bucket secured to the boom stick for pivotal movement relative thereto between a first position and a second position, and the second tool is a breaker secured to the boom stick for pivotal movement relative thereto between a stowed position and an operative position.

A hydraulically operable drive apparatus is interconnected between the boom stick and the bucket and breaker and is usable to pivotally move the bucket between its first and second positions, and to pivotally move the breaker between its stowed and operative positions. Representatively, the drive apparatus includes a plurality of hydraulic cylinder assemblies operatively interconnected between the boom stick and the bucket and breaker.

The bucket, when the breaker is in its stowed position, is movable by the drive apparatus to the second bucket position and is usable in conjunction with the boom stick, and independently of the breaker, to perform a digging operation. The breaker, when the bucket is in its first position, is movable by the drive apparatus to the breaker's operative position and is usable in conjunction with the boom stick, and independently of the bucket, to perform a breaking operation. Accordingly, the excavating machine may be advantageously utilized to perform both digging and breaking operations without equipment change-out on the boom stick.

A primary advantage of the present invention's various embodiments is that it provides an extremely durable trunnion assembly for pivotal connection of the tool to the bracket. Another advantage is that it provides a new and durable stop mechanism, configured to avoid distortion of the side plates. Another advantage is that it is easy to disassemble the trunnion assembly to replace or service tool components. Another advantage is that it provides a reliable and effective means for lubricating the bearing surface of the trunnion assembly to ensure reliable operation of the tool.

In accordance with a preferred embodiment thereof, an excavating tool system for use on an excavating machine is provided. A bracket is located on the underside of a boom stick. The bracket has a first pivot and a second pivot. The first pivot is a trunnion. An excavating tool is pivotally secured at one end to the trunnion. The excavating tool has a third pivot located thereon between its one end and its opposite end. A hydraulic cylinder is pivotally secured at one end to the second pivot and pivotally secured on its opposite end to the third pivot. In the preferred embodiment, the pivotal attachment of the excavating tool to the bracket is bifurcated, thus comprising a pair of coaxial trunnions.

In the preferred embodiment, the centers of the trunnions are located coaxially on the bracket sides slightly further from base than the location of the second pivot.

In a preferred embodiment of the present invention, each trunnion comprises an outer plate and a cylindrical bearing extending from the outer plate. A plurality of bolt holes extends through the outer plate and the sleeve bearing. In a more preferred embodiment, a hub extends from the sleeve bearing. In the more preferred embodiment, the outer plate and hub are also cylindrical.

The mounting bracket further comprises a base and a pair of parallel bracket sides extending upward from the base, each having a hub socket and a plurality of threaded holes arranged generally symmetrically around the hub sockets. The threaded holes are aligned with the bolt holes for receiving threaded fasteners (such as bolts) for attaching the trunnions to the mounting bracket sides.

In a more preferred embodiment, the trunnion further comprises a lubrication system. In the preferred embodiment, the lubrication system comprises a bore in the outer plate. A fluid channel extends from the bore to the outer surface of the bearing. A lubrication connection, such as a grease cert, is attached to the fluid channel inside the bore.

In another preferred embodiment of the present invention, a stop is formed on each bracket side. A stop bar is located on one end of the excavating tool such that the stop bar engages the stop members to limit the pivotal rotation of the excavating tool.

These embodiments have the advantage of being easily retrofit onto excavating machines without modification of the hydraulic system. An additional advantage is the lower cost of materials and installation. Optionally, an uncontrolled hydraulic or pneumatic cylinder may be used to prevent free fall of the breaker upon release of the latch-lock. An advantage of this embodiment is increased safety.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1discloses earth-excavating machine10in accordance with a preferred embodiment of the present invention. A breaker assembly100is mounted on boom stick200in addition to excavating bucket300. Breaker assembly100is an excavating tool pivotally attached to excavating machine10at a first pivot102, a second pivot104, and a third pivot106. A bracket140is rigidly attached to boom stick200by welding or other means of secure attachment. In the preferred embodiment, breaker assembly100is pivotally attached to a bifurcated first pivot102on bracket140.

A single hydraulic cylinder assembly110is pivotally attached at one end to second pivot104on bracket140. Hydraulic cylinder assembly110is pivotally attached at its other end to third pivot106on breaker assembly100. In the most preferred embodiment, the distance between first pivot102and second pivot104is less than the distance between first pivot102and the third pivot106. A latch190is located on boom stick200. When breaker assembly100is in the retracted position, latch190engages strike132(best seen inFIG. 4) so that breaker assembly100remains in the locked or stowed position.

FIGS. 2 and 3are isometric and side views, respectively, of an alternative mounting system.FIG. 2illustrates bracket140and latch190ofFIG. 1attached to a plate202by welding or other similarly secure means. In this embodiment, latch190can be located in proper alignment with bracket140and breaker assembly100on plate202prior to installation on excavating machine10. Plate202can then be attached to boom stick200. The other embodiment options disclosed herein are independent of whether plate202is used or not, and the various embodiments of the invention are not dependent upon the attachment option illustrated inFIGS. 2 and 3.

As shown inFIG. 1, bracket140is attached to boom stick200. Referring toFIG. 2, one end of hydraulic cylinder110is pivotally coupled to bracket140. The opposite end of hydraulic cylinder110is pivotally coupled to third pivot106between a first body section112and a second body section114. Body sections112and114are pivotally coupled to bifurcated first pivot102. First pivot is comprised of a pair of coaxial trunnions160located on bracket140.

FIG. 4is an exploded view of breaker assembly100ofFIG. 1. The principal component of breaker assembly100is reciprocating breaker180, also known as a hammer. Breaker180has a replaceable cutting tool182extending from one end. A breaker end184is located on the end of breaker180opposite tool182.

InFIG. 4, body sections112and114are illustrated uncoupled. A hollow bushing116is provided on each of body section112and114for receiving trunnion160for attachment to bracket140. A series of aligned holes118are provided on body sections112and114for assembly of breaker assembly100. In the preferred embodiment, bolt protectors120are provided on the exterior of one of body section112or114(shown on body section112).

A pair of opposing lower lock plates122and a pair of upper lock plates124are provided for securing breaker180between body sections112and114. Aligned holes118are also located on lower lock plates122and upper lock plates124. Lock plates122and124are secured between breaker180and body sections112and114by nut and bolt assemblies126passing through aligned holes118. In the preferred embodiment, the nuts of nut and bolt assemblies126are of the acorn type.

A stop bar128is provided for bolted attachment between body sections112and114at aligned holes118. A pivot bar130is provided for bolted attachment between body sections112and114at aligned holes118. Third pivot106is comprised of pivot bar130. A strike132is provided for bolted attachment between body sections112and114at aligned holes118.

FIG. 5is an isometric view of breaker assembly100and boom stick200(or plate202) ofFIGS. 2 and 3, shown with body section112of breaker assembly100removed for visibility. In this view, breaker assembly100is shown in the fully extended position. As seen in this view, stop member152is secured between body sections112and114, and is located in adjacent contact with breaker end184of breaker180.

FIGS. 6-8are top, side, and isometric views, respectively, of bracket140, in which bracket140is illustrated in detail. Bracket140comprises a base142and a pair of bracket sides144extending upwards from base142in substantially parallel relationship.

Second pivot104comprises a pivot bar146located between bracket sides144. In the preferred embodiment, a pair of hub sockets148is coaxially located in bracket sides144. A series of bolt holes150are located generally symmetrically in each of bracket sides144. In a more preferred embodiment including hub sockets148, bolt holes150are located generally symmetrically around hub sockets148in bracket sides144.

In a preferred embodiment best seen inFIGS. 7 and 8, a stopping member152is formed on one end of each of bracket sides144. Stop members152of bracket sides144are in substantial alignment with one another.

FIGS. 9-11are isometric, front, and side cross-sectional views of trunnion160, in which trunnion160is illustrated in detail. Trunnion160has an outer plate162. A cylindrical bearing164extends coaxially inwards from outer plate162. Bearing164contacts bushing116in a bearing relationship when breaker assembly100is fully assembled. In a more preferred embodiment, a hub166extends coaxially inwards from bearing164.

In the preferred embodiment, a plurality of bolt holes168extend through outer plate162and cylindrical bearing164in generally symmetric relationship. In a more preferred embodiment including hub166, bolt holes168are located in a ring around hub166. In a more preferred embodiment, bolt holes168include countersunk portions170for receiving the heads of bolts.

In a more preferred embodiment, trunnion160further comprises a lubrication system172. A lubrication connection174, such as a grease nipple, is attached to trunnion160, preferably within a bore176. A fluid channel178connects lubrication connection174to the surface of cylindrical bearing164. Optionally, fluid channel178may intersect the surface of bearing164in more than one location.

Operation of the Preferred Embodiments

Experience in field operation of an excavating tool in accordance with the disclosure of U.S. Pat. No. 6,751,896 has disclosed the opportunity for improvements in the invention of that patent, which are particular to an excavating machine having a deployable hammer pivotally attached to a boom stick. Specifically, the deployment system may suffer premature destruction of breaker assembly100.

Referring toFIGS. 1 through 5of the drawings, the reference numeral100generally designates a breaker assembly. Breaker assembly100is specifically designed to couple to either a new or existing boom arm, such as boom stick200, allowing easy retrofit onto excavating machines without modification of the hydraulic system. In an alternative mounting arrangement, bracket140and latch190can be welded to a flat plate202. By this method, breaker assembly100and latch190can be pre-aligned, simplifying and accelerating the installation of the device.

The disclosed configuration allows an excavating machine10to have multiple uses, and therefore reduce the cost of operation. The deployment and retraction of breaker assembly100is accomplished by the relationships between breaker assembly100, boom stick200, and hydraulic cylinder110, as associated with the configuration first pivot102, second pivot104, and third pivot106. In the most preferred embodiment, the distance between first pivot102and the second pivot104is less than the distance between first pivot102and third pivot106.

As illustrated inFIG. 1, first pivot102and second pivot104are located on bracket140. In the preferred embodiment, first pivot102is bifurcated. This configuration allows for the most complete retraction of breaker assembly100without physically interfering with first pivot102. Hydraulic cylinder assembly110is pivotally attached at one end to second pivot104on bracket140. Hydraulic cylinder assembly110is pivotally attached at its other end to third pivot106on breaker assembly100. A latch190secures breaker assembly100in a retracted position. Release of latch190and expansion of hydraulic cylinder110results in quick rotation and deployment of breaker assembly100.

In the preferred embodiment, first pivot102is comprised of a pair of coaxial trunnions160located on bracket140. Trunnions160are fully illustrated inFIGS. 9,10and11. Trunnions160provide pivotal coupling between breaker assembly100and bracket140.

Third pivot106comprises a pivot bar130coupled between body sections112and114. Pivot bar130provides pivotal coupling between hydraulic cylinder110and breaker assembly100.

As seen inFIGS. 6 through 8, bracket140is comprised of three main pieces: a base142and a pair of substantially parallel sides144extending orthogonally upwards from base142. Coaxial hub sockets148are located on sides144. Bolt holes150are located symmetrically around hub sockets148. Stop members152are located on one end of sides144.

As seen inFIGS. 9-11, each trunnion160is comprised of outer plate162, cylindrical bearing164, and hub166. Bolt holes168are located symmetrically through outer plate162and cylindrical bearing164. When trunnions160are inserted into bushings116of body sections112and114, bolt holes168align with bolt holes150on bracket sides144. This permits threaded fasteners to secure trunnions160to bracket140. Countersunk portions170provide protection for the fasteners during excavating activities, thus adding durability to the system. Bushings116of body sections112and114are located on bearings164in a bearing relationship when breaker assembly100is fully assembled.

In a more preferred embodiment, trunnion160further comprises lubrication system172. Lubrication system172comprises lubrication connection174at, such as a grease cert for adding grease, attached to fluid channel178within trunnion160. Preferably, lubrication connection174is located within bore176to provide protection during excavating activities, thus adding durability to the tool system. Fluid channel178connects lubrication connection174to the surface of cylindrical bearing164. Optionally, fluid channel178may intersect the surface of bearing164in more than one location.

Lubrication system172thus provides the advantage of a protected and accessible means of maintaining lubrication at first pivot102, which receives the heaviest load and impacts of the system. The large bearing area provided by cylindrical bearing164, when lubricated, has the advantage of distributing the significant impact forces of operation over a larger area. Similarly, the use of hubs166and multiple threaded fasteners (not illustrated) through bolt holes150to secure trunnions160to bracket140distributes the impact forces of operation over the collectively larger cross-sectional area of the multiple fasteners and hubs166.

As best seen inFIG. 12, an advantage of a preferred embodiment of the present invention is that use of trunnions160facilitates rapid installation and removal of breaker assembly100from excavation machine10. This is necessary when reciprocating breaker180requires maintenance or replacement, as often occurs with high-energy tools operating in harsh environments.

As illustrated inFIG. 4, aligned holes118are provided on body sections112and114for assembly of breaker assembly100. In the preferred embodiment, bolt protectors120are provided on the exterior of one of body section112or114(shown on body section112) for receiving the bolt portions of nut and bolt assemblies126. Additionally, in the preferred embodiment, the nut portions of nut and bolt assemblies126are of the acorn type. It has been found that fastener heads such as bolt heads and nuts can be quickly destroyed during excavating procedures making breaker assembly100difficult to remove and service. Thus, the configured fasteners126and protectors120provide the advantage of increased durability. Additionally, bolt protectors secure bolt portions of nut and bolt assemblies126from rotation, therefore having the advantage of simplifying service by only needing to apply torque tooling, such as a wrench, to the nuts portions of nut and bolt assemblies126located on one of body sections112or114.

Nut and bolt assemblies126connect through aligned holes118to secure lower lock plates122and upper lock plates124around breaker180and between body sections112and114. Additionally, nut and bolt assemblies126connect through aligned holes118to secure pivot bar130, stop bar152, and strike132between body sections112and114at aligned holes118. Stop bar152is located immediately adjacent to breaker end184of breaker180.

Strike132provides a means of engagement with latch190when it is desired to retain breaker assembly100in the retracted, or stowed, position. The retracted, or stowed, position is illustrated inFIG. 1.

FIG. 5is an isometric view of breaker assembly100and boom stick200(or plate202) with side112of breaker assembly100removed for visibility. In this view, breaker assembly100is shown in the fully extended position. It is necessary to limit the maximum extension of breaker assembly100to prevent damage to hydraulic cylinder110. It is in the fully extended position that reciprocal breaker180is operating and engaging formation or matter for destruction and, thus, the position in which highest impact forces are being imparted to excavating machine10and breaker assembly100.

In a preferred embodiment of the present invention illustrated inFIG. 5, stop members152on bracket140engage stop bar128, which is abutted to breaker end184of breaker180. Instead of transferring the impact forces of operation to body sections112and114, the forces are transferred directly to boom stick200through breaker180, stop bar128and bracket140. This configuration has the advantage of preventing separation of body sections112and114and premature failure of breaker assembly100during operation. Besides a substantial increase in durability, this configuration simplifies construction of breaker assembly100and bracket140.

Another advantage of the present invention is that the bucket can be operated without fully stowing the breaker. Likewise, the breaker may be operated without the necessity to fully extend the bucket. This increases the efficiency of the excavation process by providing immediate access to each of the tools, without delay. Another advantage of this capability is that it further increases the efficiency of the excavation process by rendering the bucket available to frequently scrape away the freshly generated cuttings so the breaker tool is always exposed to fresh refusal material, avoiding operation against previously generated cuttings. Another advantage of this capability is that by avoiding operation against previously generated cuttings, the breaker tool will last longer.