Abstract:
An automatic monitoring and display system for use with a digging machine in order to excavate holes having a predetermined depth and an excavation slope pitch from ground level to hole depth. The machine has a boom, a dipper stick connected to the boom and a bucket at the end of the dipper stick, all interconnected by three pivots. Only two sensors are used to detect the position of the bucket relative to a zero reference signal which is stored in a processor. The operator of the machine has a console whereby to select an excavation depth as well as a slope pitch angle and the console will display to him the hole depth and the percentage pitch on the slope as the excavation proceeds. The operator can reset his zero reference signal at any time from anywhere.

Description:
TECHNICAL FIELD 
     The present invention relates to a programmable automatic monitoring and display system for use with a digging machine whereby to monitor the excavation of a hole having a preset desired depth and a slope pitch angle from ground level. 
     BACKGROUND ART 
     It is known in the art to provide automatic monitoring systems in association with digging machines whereby to preset in a computer a predetermined depth for an excavation and upon excavating the hole, signals are provided to the operator concerning the position of the digging teeth of the bucket relative to the desired depth. Accordingly, the operator is continuously aware of the depth of the hole, particularly, in instances where the position of the bucket teeth is not visible. It is important when excavating holes for foundations, etc., that the depth of the hole be maintained as close as possible to the desired depth. Most methods are manual and labor intensive as an assistant is required to effectuate the measurements and relay this information to the machine operator. Such a method is also dangerous since the assistant is exposed to all sorts of hazardous situations and particularly when the weather is inclement. 
     U.S. Pat. No. 4,491,927 discloses a depth monitoring system of the type as disclosed in the present application whereby a computer is utilized to compute the trigonometric relationship between the boom, dipper stick and bucket. In that particular patent, the trigonometric equation involves the addition of three angular relationships between the boom, dipper stick and the bucket. The depth of the hole is also measured from the top edge of a vertical surveyor stake implanted in the ground to serve as a reference guide. The stick has a predetermined height above the level of the ground and this height is subtracted by the computer from the inputted measurements. Because the system utilizes three sensors, the set-up of the computer is more complicated and time consuming. Also, it is susceptible to errors as the alignment of the bucket with the dipper stick is far away from the operator, who sits in the cabin of the machine, and it is difficult to align these perfectly by using the eye. Although this system is adequate for excavating holes primarily for foundations, it cannot excavate slope angles associated with the hole or slope excavation for existing holes or trenches, ditches, etc. 
     SUMMARY OF INVENTION 
     It is a feature of the present invention to provide an automatic monitoring and display system in combination with a digging machine for excavating a hole having both a predetermined depth and an excavation slope pitch from ground level and which substantially overcomes the above-mentioned disadvantage of the prior art. 
     Another feature of the present invention is to provide an automatic monitoring and display system in combination with a digging machine for excavating a hole having an excavation slope pitch from ground level to hole depth and wherein the system utilizes only two inclinometer sensors associated with a boom, a dipper stick and a bucket, all interconnected together and to the machine by three pivot points. 
     Another feature of the present invention is to provide an automatic monitoring and display system in combination with a digging machine for excavating a hole having an excavation slope pitch from ground level to hole depth and wherein the operator of the digging machine can reset a zero reference signal at any ground point to excavate a hole as well as a slope pitch from either the top ground level or the bottom ground level at the base of the excavation. 
     It is a further feature of the present invention to provide an automatic monitoring and display system in combination with a digging machine for excavating a hole having an excavation slope pitch from ground level to hole depth and wherein the bucket and dipper stick are aligned at a predetermined position during the set-up mode by visual aligning markers provided on the bucket and dipper stick. 
     According to the above features, from a broad aspect, the present invention provides an automatic monitoring and display system in combination with a digging machine for excavating a hole having a predetermined depth and an excavation slope pitch from ground level to hole depth. The digging machine has a boom with a first pivot at a near end connected to a machine body. A dipper stick is pivotally connected to a far end of the boom by a second pivot. A bucket is pivotally connected to a far end of the dipper stick by a third pivot. The bucket has digging teeth at an extreme lower edge thereof. A first inclinometer sensor is secured to the boom close to the first pivot. A second inclinometer sensor is secured to the dipper stick close to the second pivot. A first aligning marker is provided on the far end of the dipper stick and disposed for visual access to a machine operator position. A second marker is provided on the bucket and disposed for alignment with the first marker. The first and second markers, when aligned, position the digging teeth in alignment with a longitudinal axis of the dipper stick passing through the second and third pivot. Memory storage means is provided for storing signals indicative of boom length between the first and second pivot, combined length of the dipper stick and the bucket from the second pivot to the digging teeth of the bucket, and mathematical information for calculating excavation depth and excavation slope angle. Processor means is provided for processing position signals received from the first and second inclinometer sensors relative to a preset virtual zero signal. The processor means feeds resultant signals to a display processor means for providing a visual display to a machine operator indicative of excavation depth and excavation slope pitch. A console has a first function switch means for programming for desired hole excavation depth and a second function switch means for programming desired slope pitch. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
     FIG. 1 is a schematic illustration of a digging machine incorporating inclinometers connected to the boom and dipper stick to feed information signals to a monitoring and display system located in the cabin to identify the position of the digging teeth of the bucket; 
     FIG. 2A is a fragmented perspective view illustrating the position of the visual aligning markers whereby to align the bucket teeth with a specific axis of the dipper stick; 
     FIG. 2B is a side view of the dipper stick, and bucket illustrating their alignment with the specific axis; 
     FIG. 3 is a simplified schematic plan view of an inclinometer sensor; 
     FIG. 4 is a block diagram showing the computerized system; and 
     FIG. 5 is a flow chart of the program for inputting and processing the computerized system of FIG.  4 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings and more particularly to FIG. 1, there is shown generally at  10  a digging machine for excavating a hole  11  having a predetermined depth from ground level  12  to hole bottom  13 . An important aspect of the present invention is that the system can also excavate a slope pitch  14  having a predetermined inclination angle as desired by the operator and stored in the computerized system. 
     As hereinshown the digging machine  10  has a boom  15  which is secured at a near end  16  by a pivot connection  17  to the machine body  18 . A dipper stick  19  is pivotally connected to the far end  20  of the boom  15  by a second pivot connection  21 . A digging bucket  22  is also pivotally connected to the far end  23  of the dipper stick  19  by a third pivot connection  24 . A first inclinometer sensor  25 , and as will be described in more detail with respect to FIG. 3, later on, is secured to the boom  15  close to the first pivot connection  17 . A second inclinometer sensor  25 ′ is secured to the dipper stick close to the second pivot connection  21 . 
     As shown in FIG. 2, the digging bucket  22  and the far end section  23  of the dipper stick  19  are each provided with a visual aligning marker. As hereinshown a first marker  26  is permanently affixed on a portion  27  of the far end section  23  of the dipper stick on each side thereof adjacent to the bucket connecting flanges  28 . A second position marker  29  is also permanently affixed to the connecting flanges  28  of the digging bucket  22 . When these two visual markers are aligned one adjacent the other, the bucket digging teeth  30  as shown in FIG. 2B are positioned in alignment with a longitudinal axis  31  of the dipper stick  19  passing through the second and third pivot connections  21  and  24 , respectively. This alignment is effectuated with the boom in any position such that the operator which is in the cabin  32  of the digging machine  10  has visual access thereto. This position is illustrated by reference numeral  33  in FIG.  1 . This type of alignment aid is easy to set up, is error free, and saves time to the machine operator. 
     FIG. 3 illustrates the construction of one of the inclinometer sensors, herein sensor  25 . As hereinshown each inclinometer sensor has a sealed housing  34  and a plumb weight  35  is secured therein on a pendulum connection which comprises a pivot connection  36  and a depending arm  37 . The plumb weight  35  provides a signal of its true vertical position relative to the vertical axis  38 . An attachment ring  39  is provided to connect the sensor to the boom and dipper stick. Accordingly, as the boom is displaced, the housing will be displaced but the plumb weight  35  will maintain its alignment with the true vertical axis  38 . Accordingly, an angle signal will be generated concerning the position of the boom. The operation of this sensor is well known in the art. It also incorporates electronic circuits to generate these signals as well as a connector cable  40 , see FIG. 4, to feed the signals to the electronic processing system  41  which is housed in the cabin  32  of the digging machine  10 . 
     As shown in FIG. 4, the electronic processing (CPU) system  41  is provided with a power supply  42 , a central processing unit  43  and two channels  44  and  45  feeding the CPU and associated respectively with the sensors  25  and  25 ′ connected to the boom and dipper stick. An inverter  46  feeds the power supply  42  and connects to the 12 volt D.C. battery of the digging machine (not shown). A console  47  is mounted in the cabin  32  and accessible to the operator of the machine. It is provided with a visual display  48 , function buttons  49  and data entry buttons So to enter the desired data concerning hole depth and slope angle pitch. Each of the sensors has an integrated micro-computer (not shown) which permits it to determine its position in degrees which are transmitted to the CPU  43  through the channels  44  and  45  and which converts these signals into percentages which are displayed in the windows  51  on the display  48 . The display can also be provided as a computer screen. The windows  52  display hole depth. 
     The horizontal level  12  or any position where the teeth of the bucket are positioned represents 0 degrees or 360 degrees when programming the system to set a virtual zero degree setting. Once the system is set to virtual zero, the sensor  25  will read the position of the first and second pivots and the sensor  25 ′ will read the position of the second and third pivots. Each of the sensors will transmit signals in degrees in their respective channels to feed the CPU  43  which treats these signals and feeds the resultant signal to the display on the console  47 . 
     During calibration of the system, the operator enters the length of the boom  15  from pivot  17  to pivot  21  into the computer and this information is stored in the memory of the computer. This is done by the use the keyboard  50  and the ENTER switch  55 . Secondly, the operator measures the distance from the pivot  21  to the tip of the digging teeth  30  and enters this measurement into the memory of the computer in the same fashion. The combined dipper stick and bucket measurement is taken with the dipper stick and bucket aligned as shown in position  1  in FIG.  1  and namely lying in alignment on the axis  31 . 
     As illustrated in FIG. 1, when the boom is at “position  1 ”, the second pivot connection  21  and the third pivot connection  24  are in alignment on a horizontal axis and it represents a reference point of 0 degrees which is entered into the computer by the operator. As previously described, the bucket teeth  30  have already been aligned with the dipper stick  19  or may be aligned at this instance. If after entering this virtual zero signal into the computer the dipper stick was to be displaced to its “position  2 ”, as herein illustrates in phantom lines, a position which is 90 degrees from the horizontal, the computer will generate a negative signal. However, if the virtual zero signal is entered with the dipper stick at the position shown in phantom line, wherein the dipper stick extends vertically, then if the dipper stick goes back to ground level, the computer will provide a positive signal to the operator as the bucket teeth are being displaced above the virtual zero angle setting. 
     The second sensor  25 ′ monitors the position of the third pivot connection  24  to indicate the position of the bucket teeth. The sensors read the position of the pivot points  17 ,  21  and  22  in degrees. They transmit these signals to the computer (CPU) where they are converted into percentage to be displayed on the console. If the pivot  21  is at the same level as pivot  17 , it will indicate 0 degrees. If the pivot  21  is above pivot  17 , it will indicate an increase angle in degrees. If the pivot  21  is below the pivot  17 , a console will be fed a negative degree signal. To indicate the hole depth, it is the same principle except that the signals will be converted in inches or centimeters depending on the “mode” switch F 1  for imperial measurements or F 2  for metric measurements. 
     The virtual zero signals are set by the operator on the keyboard and this can be done during the excavation of the hole by positioning the digging teeth  30  on a ground surface and the operator will depress the function switch  1  to enter hole depth and switch  2  for the slope inclination angle. Once the switch buttons are depressed he can then effectuate his zero setting. The computer will then display positive or negative signals to the operator so that he is continuously updated on depth as well as inclination angle of the slope as he operates the machine. For example, if the operator wishes to dig a hole of six feet deep with a slope pitch of 15 percent at both ends, he resets the first function switch  1  enter at the level reference. The second function switch  2  enter is reset on the top of the slope. The operator begins digging the slope until he sees −15 on the display  51  and he keeps this pitch until he sees −72 on the screen. On the other end of the excavation he resets the second function  2  enter from the bottom of the excavation and then begins to excavate the slope until he reads 15 percent positive on the display  51  and he keeps this pitch until he reaches the ground level above the hole. 
     Referring now to FIG. 5 of the drawings, there is shown the flow chart of the program for inputting information in the memory of the computer and the execution of the calculation and displays. Referring to the steps of the flow chart and as shown at step  60 , the boom lengths are measured as above described and the data is entered into the computer by the keyboard  50 . The step of automatic feeding the data from the sensors  25  and  25 ′ is expressed by steps  61  and  62 . All of this data is inserted in a conversion function of the system illustrated at step  63  in the computer. These values are then displayed on the screen  48  as expressed by step  64 . Also, the data conversion step  63  then feeds signals to computer circuitry which effectuates the mathematical treatment of the information signals, as exemplified by step  65  and the resultant signals representative of the absolute height value are obtained in step  66  and absolute flow value in step  67 . These values are processed in step  68  in relation to a virtual zero setting signal as entered into the memory of the computer by the operator and representative at step  69 . The computer then calculates the vectorial slope angle between active position and the virtual zero signal in step  70  to feed the display  51  with a degree signal in either the imperial notation represented by step  71  or the metric notation as represented by step  72 . 
     It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein, provided such modifications fall within the scope of the appended claims.