Thumb Assembly

A thumb actuator for a no-link type thumb assembly includes a cylinder body configured to be pivotally connected to a mounting bracket. The thumb actuator further includes a piston assembly having a piston and a piston rod configured to be pivotally connected to a thumb. Further, a ratio of a retracted length to a stroke length of the thumb actuator is in a range of about 1.9 to 2.2.

DETAILED DESCRIPTION

FIG. 1illustrates a side view of a machine100, such as a hydraulic implemented. The machine100may include an implement system102configured to move an implement104, a drive system106for propelling the machine100, a power source108that provides power to the implement system102and the drive system106, and an operator station110to control the movement of the implement104and the machine100.

As illustrated inFIG. 1, the implement system102may include a boom member112pivotally connected to a frame114of the machine100and configured to pivot in a vertical plane about a first horizontal axis (not shown) relative to a ground116by a pair of first hydraulic actuators118(only one side shown inFIG. 1). The implement system102may also include a stick member120pivotally connected to the boom member112and configured to pivot in the vertical plane about a second horizontal axis122by a second hydraulic actuator124. Further, the implement104is pivotally connected to the stick member120and configured to pivot in the vertical plane about a third horizontal axis126by a third hydraulic actuator128.

According to an embodiment, the implement system102further includes a no-link type thumb assembly130. The no-link type thumb assembly130may include a thumb132pivotally connected to the stick member120and also configured to pivot in the vertical plane about the third horizontal axis126by a thumb actuator134. The power source108may embody an engine such as, for example, a diesel engine, a gasoline engine, a gaseous fuel-powered engine, or any other type of combustion engine known in the art. It is contemplated that the power source108may alternatively embody a non-combustion source of power such as a fuel cell, a power storage device, or another source known in the art. The power source108may produce a mechanical or electrical power output that may be used to pressurize a hydraulic fluid for moving the hydraulic actuators118,124,128and134.

FIGS. 2 and 3illustrate, a perspective view of the stick member120and the no-link type thumb assembly130with the thumb actuator134in a retracted position and an extended position, respectively. As illustrated, the thumb actuator134may have a retracted length R corresponding to the retracted position (seeFIG. 2) and a stroke length S corresponding to the extended position (seeFIG. 3). Further, as illustrated inFIG. 2, in the retracted position, the thumb132is in a stowed position at a stow height H with respect to the stick member120. In an aspect of the present disclosure, a ratio of the retracted length R to the stroke length S, of the thumb actuator134, may lie in a pre-determined range from about 1.9 to 2.2. In an embodiment, the ratio of the retracted length R to the stroke length S may be 2.1. It will be apparent to a person having ordinary skill in the art that the pre-determined range for the ratio of the retracted length R to the stroke length S is exemplary and may vary based on the application and the size of the machine100.

According to an embodiment, the thumb actuator134includes a cylinder body136and a piston assembly138. The piston assembly138may include a piston140and a piston rod142(seeFIG. 3), such that a distal end144of the piston rod142is pivotally connected to the thumb132at an attachment point146. Further, the cylinder body136is pivotally connected to a mounting bracket148disposed on the stick member120. In an embodiment of the present disclosure, the mounting bracket148may be attached to the stick member120at a pre-determined distance D1from a stick pin150by various well known fastening means for example, but not limited to, welding, bolts. Moreover, the mounting bracket148may be formed integral with the stick member120. Further, it will be apparent to a person having ordinary skill in the art that the stick pin150may be a distal point on the stick member120and may or may not coincide with the third horizontal axis126.

FIG. 4illustrates a side view of the thumb actuator134, according to an aspect of the present disclosure. The cylinder body136of the thumb actuator134may include a main portion152and an extension portion154such that the piston140(as shown in dashed lines) is configured to reciprocate substantially within the main portion152. In an aspect, the extension portion154may be an unoccupied or empty structure such that the extension portion154may increase the retracted length R of the thumb actuator134corresponding to the retracted position of the thumb actuator134. Further, a first barrel pin bore156configured to interconnect the mounting bracket148(seeFIGS. 1-3) and the extension portion154. A second barrel pin bore158is configured to be connected to the attachment point146on the thumb132(see FIGS.1-3). An end plate160, for example a solid plate, may be configured to interconnect the extension portion154and the main portion152of the cylinder body136. Further, the cylinder body136may include ports162at each end of the main portion152and configured to supply a hydraulic fluid for both the retraction and extension of the piston140. The ports162may further be connected to hydraulic tubes164which traverse the main portion152and the extension portion154, and terminate close to the first barrel pin bore156to minimize rotational movement of hydraulic hoses and fittings during normal operation.

INDUSTRIAL APPLICABILITY

The industrial applicability of the no-link type thumb assembly130described herein will be readily appreciated from the foregoing discussion. Although, in the illustrated embodiment, the machine100is embodied as the hydraulic excavator, in various other embodiments, the machine100may be, but not limited to, an, a backhoe loader, an industrial loader, a skidder, an excavator, and a hydraulic shovel, or the like. The machine100may be a fixed or mobile machine that performs operations associated with an industry such as mining, construction, demolition, farming, or any other industry known in the art.

FIG. 5illustrates a perspective view of a machine500with a stick member502with a link-type thumb assembly504which is pivotally connected to the stick member502by a thumb actuator506. The link-type thumb assembly504may include a first link member508pivotally connected to the stick member502. The first link member508is further connected to a second link member509. Further, the second link member509is connected to an attachment point512provided on a thumb510. The thumb actuator506includes a cylinder body514and a piston assembly516. The piston assembly516is pivotally connected to the first link member508. Further, the cylinder body514is pivotally connected to a mounting bracket518disposed on the stick member502. In an embodiment of the present disclosure, the mounting bracket518may be attached to the stick member502at a pre-determined distance D2from a stick pin520by various well known fastening means for example, but not limited to, welding, bolts.

As illustrated inFIGS. 3 and 5, in an aspect of the present disclosure, a singular mounting bracket148,518location on the stick members120,502is achieved for the no-link type thumb assembly130and the link-type thumb assembly504by inclusion of the extension portion154with the main portion152of the cylinder body136in case of the no-link type thumb assembly130. According to an aspect, the pre-determined distance D1of the mounting bracket148from the stick pin150of the no-link type thumb assembly130is substantially equal to the pre-determined distance D2of mounting bracket518from the stick pin520of the link-type thumb assembly504.

In an aspect of the present disclosure, the addition of extension portion154may imply a singular location of the mounting bracket148,518in terms of the pre-determined distance D1, D2for the no-link type thumb assembly130and the link-type thumb assembly504. This may increase the life of the stick members120,502. Further, the stick members120,502of the machines100,500with the mounting bracket148,518may be a single factory assembled thumb-ready stick for use with the no-link type thumb assembly130and the link-type thumb assembly504. In an aspect of the present disclosure, the ratio of retracted length R to the stroke length S being in the pre-determined range from about 1.9 to 2.2 may decrease the stowed heights H of the no-link type thumb assembly130, while maintain a high degree of rotation of the thumb132. Moreover, the thumb actuator134having the ratio of retracted length R to the stroke length S of within the pre-determined range also maintains a resistance to buckling conditions.