Electrically actuated attachment system for tractor front end loaders

Electrically actuated quick attach systems for tractor front end loaders are disclosed. An electric actuator with extendable rods is connected to rotatable handles mounted on attachment mounting plates. Extension of the electric actuator rods rotates the handles and causes attachment locking pins to extend into locking positions. Retraction of the electric actuator rods rotates the handles in opposite directions and causes the locking pins to retract into unlocked positions. The electrically actuated quick attach systems may be used with compact utility tractors as well as other types of tractors.

FIELD OF THE INVENTION

The present invention relates to tractor front end loaders, and more particularly relates to electrically actuated systems for locking and unlocking attachments to compact utility tractors and other types of tractors.

BACKGROUND INFORMATION

Tractors are often equipped with front end loaders which may be used with various attachments such as buckets, forks, bale spears and the like. For example, compact utility tractor front end loaders typically have lifting capacities of 800-5,000 pounds and are mounted on tractors which typically range in horsepower from 18-45. Larger tractors having horsepowers of up to 150 or more and greater lifting capacities may also utilize front end loaders and attachments. Such tractors with front end loaders are used in commercial, agricultural, landscaping, residential and other applications.

Conventional quick attach systems for tractors such as compact utility tractors allow operators of the tractors to quickly change the attachments on the front end loader by manually moving levers which lock and unlock the attachment to the quick attach system by means of retractable locking pins. The mounting envelope or size of such systems is an industry standard which is common among compact utility tractor front end loaders. This standard is the SAE Surface Vehicle Standard J2513.

SUMMARY OF THE INVENTION

The present invention provides an electrically powered actuator for tractor quick attach systems. By activating the electric actuator, the operator has the ability to lock and unlock an attachment to the tractor quick attach system from the tractor operator's position. Tractor front end loader attachments may be quickly and conveniently changed with the present electric actuator in comparison with conventional systems which require manual movement of levers by the operator.

An aspect of the present invention is to provide an attachment system for mounting attachments to a tractor. The attachment system comprises handles pivotally mounted on tractor attachment mounting plates. Each handle includes a connection to an attachment locking pin and another connection to an actuator end clevis. An electric actuator is connected to the end clevises. In one embodiment, the electric actuator extends the end clevises linearly away from each other to rotate the handles and locking pins to downward locked positions. Retraction of the end clevises toward the actuator rotates the handles and retracts the locking pins to their unlocked positions.

Another aspect of the present invention is to provide a handle for a tractor attachment mounting system. The handle comprises a first region structured and arranged for pivotal mounting of the handle on a tractor attachment mounting plate, a second region structured and arranged for connecting an attachment locking pin to the handle, and a third region structured and arranged for connecting an electric actuator end clevis to the handle.

DETAILED DESCRIPTION

FIG. 1illustrates a compact utility tractor5including a front end loader8which may be equipped with an electrically actuated attachment system100in accordance with an embodiment of the present invention. As shown most clearly in the enlarged section ofFIG. 1, the electrically actuated attachment system100includes an electric actuator110mounted on a quick attach mechanism including mounting plates12, upper support members14and extendable locking pins16. The quick attach system is configured for attachment to conventional compact utility tractor attachments such as buckets, forks, bale spears and the like. Although attachment systems for compact utility tractors are primarily described herein, it is understood that the present electrically actuated attachment system may be used with other types of tractors as well.

FIG. 2illustrates a conventional manual quick attach system10including standard mounting plates12, upper support members14, extendable locking pins16and locking pin springs18. Manually operated handles20are pivotally mounted on the mounting plate12by bolts24. Each handle20also includes a slot26in which a locking pin connector28is retained. The locking pin connector28is connected to the extendable locking pin16by means of a pivotable linkage. In the position shown inFIG. 2, the handles20are in downward positions, and the locking pins16are extended to their downward locking positions. Manual movement of the handles20upward from their positions shown inFIG. 2causes rotation of the handles20around the bolts24and retraction of the locking pins16upward to their unlocked positions.

FIGS. 3-6and9illustrate an electrically actuated attachment system100in accordance with an embodiment of the present invention. The system includes an electric actuator110controlled by a switch111which may be mounted at any suitable location on the compact utility tractor. The electric actuator110includes a stationary rod at one end and an extendable rod112at the other end which may be extended away from and retracted toward the electric actuator110. Although a single extendable rod112is shown in this embodiment, the electric actuator110may alternatively include two rods extendable in opposite directions from the actuator. The rods of the electric actuator110include end clevises114which are connected by bolts134to handles120which include hand grip levers. As more fully described below, when the switch111is activated, the electric actuator110extends, which moves the handles120downward to engage the locking pins16into the attachment. Depressing the switch111reverses the direction of movement of the electric actuator110and cause the handles120to rotate upward and the locking pins16to disengage. Any suitable electric actuator110may be adapted for use in accordance with the present invention, for example, an electric actuator with an internal clutch sold by Linak U.S. Inc. under the designation LA36.

Each handle120includes a handle mounting hole122(most clearly shown inFIGS. 8 and 9) through which a handle mounting bolt124extends in order to pivotally connect the handle120to the mounting plate12. The handle120also includes a slot126which retains a locking pin connector128that is connected by a pivotable linkage surrounded by the spring18to the extendable locking pin16. The handle120further includes an extended actuator mounting tab130for connection to the end clevis114of the electric actuator110. The actuator mounting tab130has an actuator mounting hole132extending therethrough (most clearly shown inFIGS. 8 and 9).

InFIGS. 3 and 4, the end clevises114of the electric actuator110are extended, and the handles120are in their downward positions with their hand grip levers extending substantially horizontally. In this position, the locking pins16are also extended to their downward locking positions. A portion of each handle120contacts a sidewall of the mounting plate12to stop rotation of the handle120in this position.

InFIG. 5, the end clevises114of the electric actuator110are retracted to rotate the handles120around their handle mounting bolts124to their upward positions with their hand grip levers extending upward. In this position, the slots126and their respective locking pin connectors128have been rotated to thereby retract the locking pins16to their upward unlocked positions. In this position, the electric actuator110may be in its fully retracted, end of stroke position.

FIG. 6is a bottom view andFIG. 9is an exploded isometric view illustrating details of the arrangement of the end clevises114of the electric actuator110in relation to the handles120. Each end clevis114has a slot115which is aligned close to the center line of the electric actuator110. The extended actuator mounting tab130of each handle120extends into the slot115of the actuator end clevis114, and the bolt134connects these components together. This arrangement, with the centerline of the electric actuator110closely aligned with the clevis slot115and the actuator mounting tab130of the handle120, provides improved operation and reliability for the electric actuator110by reducing or eliminating side deflection or cantilever type loading conditions.

The embodiment shown inFIGS. 3-6and9has the end clevises114of the electric actuator110arranged such that they straddle the actuator mounting tab130handle120and place the centerline of load as close as possible to the centerline of the electric actuator110. When the electric actuator110is operated in this configuration, side deflection is within recommended specifications and the operational life of the actuator is maximized.

FIGS. 7 and 8illustrate a manual quick attach handle20and an electrically actuated handle120in accordance with an embodiment of the present invention, respectively. As shown inFIG. 7, the manual handle20includes a mounting hole22for pivotable attachment of the handle20to the quick attach mounting plates12. The manual handle20also includes a slot26for the locking pin connector28of the extendable locking pin16. As shown inFIG. 8, the handle120in accordance with an embodiment of the present invention includes a similar handle mounting hole122and a similar slot126. However, the handle120further includes the extended actuator mounting tab130and actuator mounting hole132extending therethrough for connection to the electric actuator110, as described above. The handle mounting hole122, locking pin linkage slot126and actuator mounting hole132are arranged at different positions or regions in the plane of the handle120.

FIGS. 10-12illustrate another electrically actuated attachment system in accordance with an embodiment of the present invention. In this embodiment, handles220are pivotally mounted on the mounting plates12by means of handle mounting bolts224. Each handle220includes a slot226which receives a locking pin connector228connected to the extendable locking pin16by a pivotable linkage surrounded by the spring18. The end clevis214of each actuator arm is connected to the handle220by an actuator mounting bolt234which extends through an actuator mounting hole232in the handle220. The actuator mounting hole232is most clearly seen inFIG. 14. Alternatively, the mounting hole232and bolt234may be replaced with a stud connected to the handle by welding or the like. Each handle220also includes a clutch stop tab236extending therefrom which stops rotation of the handle220at the desired position.

InFIG. 10, the end clevises214of the electric actuator110are extended, and the handles220are pivoted around the mounting bolts224to their downward positions with their hand grip levers extending substantially horizontally. In this position, the locking pin connectors228retained in the slots226force the extendable locking pins16to their downward locked positions. A portion of each handle220and a portion of each actuator end clevis114contacts a sidewall of the mounting plate12to stop rotation of the handle220in this position.

InFIG. 11, the end clevises214of the electric actuator110are retracted, which causes the handles220to rotate around the handle mounting bolts224until the clutch stop tabs236of the handles220contact sidewalls of the mounting plates12or the actuator110reaches its retracted end of stroke position. In this position, the slots226are rotated along with the locking pin connectors228to thereby retract the locking pins16to their upward unlocked positions. As more fully described below, a standard clutch contained in the electric actuator110may disengage when the clutch stop tabs236of the handles220contact the mounting plates12. Also, the electric actuator110may reach its fully retracted end of stroke in this position.

FIG. 12is a top view of the electrically actuated attachment system shown inFIG. 10, illustrating the alignment of the centerline of the electric actuator110with the interface between each end clevis214and each handle220in the region of the actuator mounting bolt234and actuator mounting hole232. Each end clevis214is offset to permit the mounting of the electric actuator110centerline as close as possible to the load, thereby minimizing the side deflection of the electric actuator110as well. In accordance with this embodiment of the invention, this alignment improves the operation and reliability of the electric actuator110.

FIGS. 13 and 14illustrate a manual handle20and an electrically actuated handle220in accordance with an embodiment of the present invention, respectively. As shown inFIG. 13, the manual handle20includes a mounting hole22and slot26. The electrically actuated handle220shown inFIG. 14includes a similar mounting hole222and slot226, and further includes the actuator mounting hole232and the clutch stop tab236. The handle mounting hole222, locking pin linkage slot226and actuator mounting hole or stud232are arranged at different positions or regions in the plane of the handle220.

FIG. 17is a bottom view of the electrically actuated attachment system shown inFIG. 16, illustrating the connection of the ends314to the handles320. As shown in the expanded section ofFIG. 17, the314extends between two opposing faces320aand320bof the handle320, and is secured by the actuator mountin pin334. This connection is substantially aligned with the center line of the electric actuator110, which provides improved operation and reliability for hte electric actuator110.

The embodiment shown inFIGs. 15-17has each end of the electric actuator110arranged such that it is straddled by the opposing faces320aand320bof the handles320. This places the centerline of load as close to the centerline of the electric actuator110as possible. When the electric actuator110is operated in this configuration, side deflection is within recommended specifications and the operational life of the actuator is maximized.

FIGS. 18 and 19illustrate a manual handle20and an electrically actuated handle320in accordance with an embodiment of the present invention, respectively. The manual handle20ofFIG. 18includes a mounting hole22and a hole26for the locking pin connector. The electrically actuated handle320ofFIG. 19includes a handle mounting hole322and locking pin connector hole326, as well as the extended actuator mounting tab330having the actuator mounting hole332extending therethrough. The handle mounting hole322, locking pin linkage hole326and actuator mounting hole332are arranged at different positions or regions in the plane of the handle320.

In accordance with an embodiment of the present invention, the electric actuator110includes a standard internal automatically self adjusting, bi-directional clutch mechanism of any suitable known design to determine the locked and/or unlocked position for the quick attach system. For example, the clutch may make a ratcheting sound when it is activated, providing an audible indicator to the operator. The handles120,220and320stop rotation in the locked and/or unlocked positions so as to activate the clutch mechanism of the electric actuator110. The end clevises114,214and314are preferably of a length such that the electric actuator110reaches its own internal end of stroke upon full retraction and thereby activates its internal clutch. This point may be reached when the handles are beyond center in the unlocked positions.

Electrical actuators may be prone to premature failure under certain conditions. One very undesirable condition is where the load placed on the actuator is offset from the centerline of the actuator. This will cause the actuator to deflect sideways (perpendicular to the axis of force) and ultimately cause the motor excessive stress as well as the internal components. In accordance with embodiments of the present invention, the electric actuator110is connected to the handles120,220and320such that side deflection loads are reduced or eliminated.

By mounting the electric actuator110to the handles120,220and320at locations other than the locking pin linkage pivot point, a clutch-type actuator may be used to determine locked and unlocked states of the quick attach system. The clutch-type actuator provides superior field performance and reliability as compared to limit switch actuators for this application.

The present electrically actuated system may fit both existing and newly manufactured quick attach systems within the front end loader industry. The present electrically actuated quick attach system has many advantages. It is easy to install with minimal wiring, and easy to field repair in the event the wiring gets pinched by the front end loader. The electric motor design permits fast operation, and require less power or drain on the vehicle's electrical system. The electric actuator is clean to maintain without the fluids that are required by hydraulics, and is easier and more economical to adapt to existing equipment in the field.