OPERATOR PRESENCE HANDLE FOR WORK MACHINE

SUMMARY

[0001]The present invention is directed to a control assembly for a pedestrian-operated work machine. The control assembly comprises a control panel, at least one bidirectional control lever, an operator presence handle, a first presence sensor, a second presence sensor, and a controller. The at least one bidirectional control lever mounted to the control panel. The operator presence handle is mounted to the control panel and movable between a forward position and a rearward position, and biased to a neutral position between the forward position and the rearward position.

[0002]The first presence sensor is disposed on a first side of the operator presence handle and configured to detect the position of the operator presence handle in the forward position, while the second presence sensor is disposed on a second side of the operator presence handle and configured to detect the position of the operator presence handle in the rearward position. The controller is configured to selectively permit operation of the work machine in response to a signal from at least one of the first presence sensor and the second presence sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003]FIG. 1A is a side view of a control panel for use with a work machine. The control panel has first and second levers and an operator presence handle. The operator presence handle is tilted forward relative to a vertical plane, actuating a first switch.

[0004]FIG. 1B is the control panel of FIG. 1A, with the operator presence handle tilted back relative to a vertical plane, actuating a second switch disposed on an unseen second side of the control panel.

[0005]FIG. 1C is the control panel of FIG. 1A, with the operator presence handle in a neutral, vertical position, actuating neither switch.

[0006]FIG. 2A is a top view of the control panel of FIG. 1A.

[0007]FIG. 2B is a top view of the control panel of FIG. 1B, with the second switch visible.

[0008]FIG. 2C is a top view of the control panel of FIG. 1C.

[0009]FIG. 3 is a top side perspective view of the control panel of FIG. 1C.

[0010]FIG. 4 is a top side perspective view of a trenching machine using the control panel and levers of the present invention.

DETAILED DESCRIPTION

[0011]Turning now to the figures, FIGS. 1A-1C show a control mechanism for a work machine, including an operator presence handle for use with the same.

[0012]Work machines, such as trenchers, mechanical plows, compact loaders, and the like, are used to perform jobs mechanically that would otherwise be labor-intensive.

[0013]While many such work machines have seats, cockpits, or platforms which allow for an optional operator presence device attached to a seat or platform, a “pedestrian” work machine has no such platform, as operators walk behind the work machine. FIG. 4 shows a work machine 10 with a trenching attachment 11 and a control panel 12 for controlling the operation of the work machine 10. The work machine 10 is translated across the ground by a pair of tracks 13. Other motive force means, such as wheels, may be utilized as well.

[0014]The control panel 12 contains an operator presence device so that the tracks 13 and the attachment 11 will not operate at full speed unless the device indicates an operator is present at the control panel 12.

[0015]Operator presence devices are advantageous as they prevent the work machine, and/or its attachment, from operating during periods when an operator isn't actively engaging with the work. However, many such operator presence devices are placed on seats or platforms, which are not present in pedestrian machines, such as work machine 10, arranged for walking operation. Alternatively, some pedestrian machines utilize ergonomically uncomfortable devices. The operator presence device of the present invention overcomes these difficulties.

[0016]The work machine 10 of the figures comprises a control panel 12. The control panel, shown in detail in FIGS. 1A-2C, comprises a first control lever 14, a second control lever 16, and an operator presence handle 20. The first control lever 14 is preferably bidirectional, and controls an aspect of the work machine 10. Likewise, the second control lever 16 is bidirectional, and controls a second aspect of the work machine. As shown, the first control lever has a first end 14A and a second end 14B. The second control lever has a first end 16A and a second end 16B. Each end can be held in place by an operator to operate the work machine.

[0017]Possible aspects of the work machine 10 that levers 14, 16 control are movement of the tracks 13 or other ground drive members, operation of attachments, such as digging chains, and positioning of lift arms. One exemplary use of the first and second control levers 14, 16 is for the first and second tracks 13, allowing operation and movement of the work machine 10.

[0018]Because each of the levers 14, 16 is bidirectional, it may be that both levers are held in the full forward, or fully reverse position for some time. For example, both levers 14, 16 may be pushed forward during pedestrian operations. The work machine 10 moves forward, and the operator walks behind, one hand gripping the lever 14 and the operator presence handle 20, the other hand gripping the lever 16 and the operator presence handle 20. The operator presence handle 20 may be held with an end of the levers 14, 16 for ease of operation in either the fully forward or fully reverse position. As shown, the contour of the handle 20 matches each side of the bidirectional levers 14, 16, for ease of operation with a single hand.

[0019]The operator presence handle 20 is attached to the control panel 12 about a pivot point 22. The handle 20 is proximate a first presence switch 30 on its first side 24 and on a second side 26 to a second presence switch 32. The handle 20 may be attached to these switches 30, 32, or the switches 30, 32 may detect contact or a position of the ends of each side 24, 26 of the handle 20. The operator presence handle 20 is biased to return to neutral—that is, in the Figures, a vertical orientation as shown in FIG. 1C—when no pressure is placed on it. Preferably, the operator presence handle 20 is spring biased.

[0020]When in this vertical orientation shown in FIG. 1C, neither the first presence switch 30 nor the second presence switch 32 is actuated and the handle 20 is substantially centered on a vertical axis 100. The first presence switch 30 and the second presence switch 32 cooperate to form a presence detection system, communicating by a signal with a controller.

[0021]When the operator presence handle 20 is manipulated by an operator, during use of the levers 14, 16, however, the operator presence handle 20 will tilt either slightly forward or slightly rearward. Tilting the handle 20 forward, as best shown in FIG. 1A, results in the first presence switch 30 being actuated. Tilting the handle 20 rearward, as shown in FIG. 1B, results in the first presence switch 30 being inactive, but the second presence switch 32 being actuated. The switches 30, 32 are preferably designed to be actuated when the handle 20 deviates from the vertical axis 100 a predetermined amount. The predetermined amount may be small, as little as a degree or two, which is enough to show that the operator is present at the control panel 12 and actively attending to the work machine 10.

[0022]As shown, the operator presence switches 30, 32 are mechanical switches depressed by a tab on the first side 24 and the second side 26 of the handle 20. The switches 30, 32 are each attached to the control panel 12, and provide an electrical signal to the controller to indicate whether it is actuated or not. Either the presence of, or absence of the electrical signal may be indicative of the switch's actuation. Alternatively, other switches 30, 32 may be used that use an electromagnetic signal, optical signal, or other impulse to determine the angle of the operator presence handle 20.

[0023]An electromagnetic or optical switch or sensor may operate in a non-contact manner, and may utilize visual or electromagnetic information to detect the localized presence of an end of the handle indicative of an operator's presence. The indication of an operator presence may initiate a signal to the controller as discussed above. With such a sensor, it may be possible to place both the first switch 30 and the second switch 32 on a single side 24 of the handle 20. Further, a single mechanical switch 30 may detect operator presence and activate when the handle 20 is rotated both towards and away from the switch 30.

[0024]As a further alternative, a rotational encoder may be placed at the pivot point 22 to determine when the angular orientation of the handle 20 deviates from vertical axis 100.

[0025]The pivot point 22 is preferably disposed well above the operator presence switches 30, 32, to allow the bottom portion of the operator presence handle 20 to rotate a greater distance about the pivot point. Preferably, each switch 30, 32 is rigidly attached to the control panel 12 and has enough structural support to, at full actuation, prevent further rotation of the handle 20 about the pivot point 22. Rotation stops for the handle 20 is provided by the upper structure of the control panel 12.

[0026]The switches 30, 32 are connected to a controller. When one of the switches 30, 32 is actuated, the controller allows the work machine 10 to continue operation, as dictated by the first control lever 14 and the second control lever 16. When neither of the switches 30, 32 is actuated, operation of the work machine 10 ceases, whether or not the control levers 14, 16 are actuated. When ceasing the work machine 10, the controller may shut off the prime mover of the work machine, or may, through hydraulic or electric control, simply prevent the attachment and/or the ground drive from operating, while allowing the prime mover of the work machine to continue operating, with operation of the attachment and/or ground drive to continue once an operator presence switch 30, 32 is again actuated.

[0027]Likewise, operator presence, as detected by the operator presence handle 20, may be required for starting elements of the work machine 10. For example, the attachment 11 may be started by a switch disposed at the control panel 12. Should the operator presence handle 20 be biased such that it is centered, as in FIGS. 1C and 2C, the controller may prevent the switch from starting operation of the attachment. Should the handle 20 be tilted such that one of the switches 30, 32 is actuated, the controller may allow the attachment 11 to begin operation.

[0028]When control levers 14, 16 are transitioned from one orientation to the other, for example, when the operator desires to change the direction of the work machine 10 or to begin to turn the work machine 10, the angle of the operator presence handle 20 may change during the transition. This transition may cause the handle 20 to pass through the vertical axis 100 for a short time. Therefore, the controller may include a timer, which allows for the transition between positions of the operator presence handle 20.

[0029]For example, if the handle 20 is in the position of FIGS. 1A, 2A, and the first switch 30 is depressed, and the first switch 30 is then released, the controller may wait a predetermined time before ceasing operation of the work machine 10. Such a time delay will allow for the handle 20 to be moved, during ordinary operation, into the position of FIG. 1B, with the second switch 32 depressed, without interrupting operation. Further, it will allow for ordinary ergonomic adjustments of an operator during operation, such as shifting of hand positions, adjustments for bumps in the ground surface, etc.

[0030]One exemplary predetermined time for such a delay is one half a second. Other delays may be used, such as 250 milliseconds, 1 second, or more. However, it is preferable that the predetermined time is not long enough for an operator to move substantially away from the control panel 12 while the work machine 10 is operating. The predetermined time may be adjustable by the operator through interaction with the controller.

[0031]The control panel 12 may comprise additional controls. In the Figures, the control panel comprises an attachment plunge control 50. The plunge control 50 may, in the case of a work machine 10 that is a pedestrian trencher, actuate the tilting of, and operation of, a trenching boom for uncovering a trench.

[0032]While the present invention may be used in various types of work machines 10, the particular levers 14, 16, in conjunction with switches 30, 32, may be advantageously used in an electrically powered and controlled machine.

[0033]The various features and alternative details of construction of the apparatuses described herein for the practice of the present technology will readily occur to the skilled artisan in view of the foregoing discussion, and it is to be understood that even though numerous characteristics and advantages of various embodiments of the present technology have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the technology, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present technology to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.