The population or mix of construction equipment has transformed in recent years. With the ever increasing cost of land, the square footage or size of various lots is becoming smaller. Accordingly, the size of construction equipment has likewise decreased. Construction equipment is now available in compact configurations. For example, “mini excavators” or compact excavators are available by numerous manufacturers in several size choices, due to the compact utility they offer.
Such construction equipment typically includes a bucket, scoop or similar ground moving implement mounted on a movable machine. Such an implement has multiple walls including a bottom wall. The bottom wall of the implement terminates in a forward or front edge. Alternatively, a bucket lip is secured to the front edge of the bottom wall of the implement. As used herein, the term “bucket lip” means and refers to a forward or front portion of the bucket/implement whether such portion is formed as part of the bottom wall of the implement or is secured thereto. In some implement designs, a front edge of the bucket lip has an angled surface or bevel which acts as a blade. Moreover, a series of ground engaging teeth can project longitudinally forward from the bucket lip to facilitate ground penetration the implement.
The ground engaging teeth for such implements have a form which facilitates their penetration into the ground, and they must, moreover, retain this form as long as possible during their operational life despite the wear to which they are subjected. The dimensions and shape of these teeth must be able, as far as possible, to withstand the considerable forces which occur during operation. Additionally, the connection of the teeth to the bucket lip must be sufficiently robust as to inhibit inadvertent separation of the teeth from the bucket. Moreover, the shape of the teeth must ensure good penetration of the front edge of the bottom wall of the bucket.
Ground engaging teeth typically come in two styles. One style of digging tooth involves a unitary or one-piece design including an appropriately shaped or configured tooth portion with either one, one and one half or a pair of elongate sections or legs longitudinally extending from and for securing the tooth portion to the bucket. With this design, however, and after the tooth portion of the digging tooth wears and requires replacement, there is a considerable amount of digging tooth material (throw-away) which is wasted and irretrievably lost when the worn digging tooth is replaced.
The other style of digging tooth commonly used in the industry embodies a two-piece or multipiece design. With this design, one piece of the digging tooth is configured as an adapter having a nose portion and base portion. The adapter nose portion is configured to releasably accommodate the other piece of the multipiece digging tooth design, i.e., the digging tooth or tip. To advantageously reduce the amount of throw-away, this multipiece design allows replacement of only the digging tooth or tip portion of the tooth design, when required. Typically, and depending upon digging conditions, three to ten digging tooth replacements can be used before the adapter is sufficiently worn as to require replacement.
As with the unitary tooth design, the base portion of the adapter embodies alternative designs. The first adapter base portion design includes a single leg or elongate section which engages with a top surface of the bucket lip and extends longitudinally from a body section of the adapter. This design is usually used in those applications where lesser digging forces are expected to be applied to the digging tooth during operation of the digging implement. The other adapter base portion designs include either one and one half or two bifurcated and elongated sections which embrace top and bottom vertically spaced faces of the bucket lip and extend longitudinally from the body section of the adapter.
The value of a double strap or double leg design is its increased strength over a single leg or a leg and one half designed adapter. Of course, the enhanced value of a double strap or double leg design is lost if the double legs are not operably conjoined with the body section of the adapter. Without the top and bottom elongate or leg sections being manufactured as an integral unit, or alternatively, mechanically attached to each other, the strength provided to the adapter is no greater than two separate single legs being provided on the base portion of the adapter. Regardless of the base portion design, it is highly desirable to have each elongate section, used to mount the digging tooth to the bucket, longitudinally supported along the full length of each elongate section.
Problems occur in designing teeth for such implements. One such problem involves the lack of conformity between the numerous bucket designs offered by different implement manufacturers. That is, there is little or no standardization regarding bucket or implement designs between the various bucket manufacturers. As a result, and although different manufacturers frequently list the bucket designs as being similar, an actual comparison between the bucket designs offered by different manufacturers can and often do result in: differing bucket lip thicknesses, different angles for the bevel on the bucket lip; different blunt thicknesses, and differing bolt hole location spacings and size (in the case of bolt-on adapters). Bolt-on adapters are preferred, since this allows an operator the option of removing the adapters/teeth when they desire to dig with only the bucket. Besides the above, the configuration and angle or pitch of the nose portion on the adapter can and often do differ between manufacturers.
Because of the lack of standardization between the various bucket manufacturers, when an operator needs to replace an adapter of a multipiece digging tooth or a unitary digging tooth, the operator must return to the original equipment dealer for such replacement parts since the parts made by other manufacturers are not likely to fit and mate with the particular bucket requiring new parts. Very few of the thousands of independent dealers across the country are likely to have a wide choice of different adapters or one-piece tooth designs that fit the particular needs of a specific operator. That is, to facilitate such an accommodation, each independent dealer would be required to inventory scores of various adapters and/or one-piece digging teeth. This would create tremendous inventories, confusion and monetary waste.
Thus, there is a need and continuing desire for a universal digging tooth attachment apparatus which accommodates differences or variations between: the thicknesses of the bucket lip used on various implements, the angle of the bevel on the bucket lip, blunt thickness, and bolt-hole location spacings and size (in the case of bolt-on adapters), as well as differences between the angle or pitch of the nose portion of the adapter.