Patent Publication Number: US-2017362798-A1

Title: System and method to drive vacuum excavator

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. provisional application Ser. No. 62/350,494 filed on Jun. 15, 2016, all the contents of which are herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to the field of vacuum excavation, and, more particularly, to a system and method to drive a vacuum excavator. 
     BACKGROUND 
     Industrial vacuum equipment has dozens of wet and dry uses such as locating underground utilities (potholing), hydro excavation, air excavation and vacuum excavation. In addition, the equipment can be used for directional drilling slurry removal, industrial clean-up, waste clean-up, lateral and storm drain clean-out, oil spill clean-up and other natural disaster clean-up applications, signs and headstone setting, for example. The vacuum equipment may be mounted to a truck or trailer and is typically powered by gas or diesel engines. 
     A dedicated engine may be mounted alongside the vacuum equipment to power the equipment. The truck could include a transmission-driven power take-off for driving the equipment and the engine can be used to power both the truck and the auxiliary equipment. A split shaft transfer cases is one type of PTO that has been used to allow the engine to power either the rear wheels or the deck equipment. When driving, the engine power is connected straight through to the drive axle. In the PTO position, the axle drive shaft is disengaged and the engine power is re-directed up through the gear train to outputs to operate various equipment. 
     A shortcoming of the prior art is the difficulty and expense in adapting a truck transmission to a power take-off. 
     SUMMARY 
     In view of the foregoing background, it is therefore an object of the present invention to provide a system to drive a vacuum excavator that is easy and cost effective to implement. The system to drive vacuum equipment on a truck having an engine and a transmission includes a power take-off (PTO) unit configured to be coupled to a PTO port located on a side of the transmission. The system also includes a PTO shaft coupled to the PTO unit, vacuum equipment mounted to the truck, and a first gear box coupled to the PTO shaft and the first gear box configured to transfer power to the vacuum equipment. In addition, the system includes at least one belt coupled to the gear box, wherein the at least one belt drives additional auxiliary equipment. The additional auxiliary equipment comprises at least one of a water pump and a hydraulic pump, where the hydraulic pump is configured to stop and reverse a flow of hydraulic fluid to stop and reverse a rotational direction of air through the blower. 
     In another embodiment, a method to drive a vacuum excavator is disclosed. The method to drive vacuum equipment on a truck having an engine and a transmission includes coupling a power take-off (PTO) unit to a PTO port located on a side of the transmission, coupling a PTO shaft to the PTO unit, and transferring power to the vacuum equipment mounted to the truck via a first gear box coupled to the PTO shaft. The method also includes driving a hydraulic pump coupled to a blower, and controlling a direction of flow of hydraulic fluid of the hydraulic pump in order to control a direction of air flow through the blower. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top perspective view of a truck and vacuum equipment mounted thereon; 
         FIG. 2  is a partial right side elevational view of the truck and system to drive the vacuum equipment of  FIG. 1 ; 
         FIG. 3  is a perspective left side view of the system to drive the vacuum equipment shown in  FIG. 2 ; and 
         FIG. 4  is a flow diagram of a method to drive vacuum equipment. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     Referring now to  FIGS. 1-3 , a particular illustrative embodiment of a system to drive vacuum equipment  102  on a truck  104  having an engine  106  and a transmission  118  is disclosed. The system includes a power take-off (PTO) unit  120  coupled to a PTO port  121  located on a side of the transmission  118 . A PTO shaft  122  is coupled to the PTO unit  120 . The vacuum equipment  102  mounted to the truck  104  is coupled to the PTO shaft  122  and configured to be driven by the PTO shaft  122 . Substantially all available horsepower of the engine  106  is transferred to the vacuum equipment  102  via the PTO shaft  122 . 
     A debris tank  108  is also mounted to the truck  104  and a vacuum hose  111  is coupled to the debris tank  108  by an inlet of the debris tank  108 . The debris tank  108  can be placed under a vacuum by a blower  114  coupled to the debris tank  108 . In turn, the vacuum hose  111  is also coupled to the debris tank  108  and has suction that is used to excavate materials into the debris tank  108 . A filter housing  112  is coupled to the blower  114 . 
     In a particular embodiment, the blower  114  may be a positive displacement pump, for example. The blower  114  is driven by a hydraulic pump  116  coupled to the PTO unit  120 . In particular, the hydraulic pump  116  is configured to control the direction of air flow through the blower  114  (and in turn the debris tank  108  and vacuum hose  111 ) in response to a direction of the flow of hydraulic fluid through the hydraulic pump  116 . As the hydraulic pump  116  is driven by the PTO unit  120 , the direction of hydraulic fluid is selected so that the blower  114  is also moving air flow in a first direction (e.g., providing a vacuum). 
     For example, a first conduit  126  is coupled to a first port of the blower  114  and a second conduit  122  is coupled to a second port of the blower  114 . The first conduit  126  can be for suction and the second conduit  122  can be for discharge when the air flow is in first direction. When the direction of the hydraulic fluid is reversed, the first conduit  126  then becomes the discharge and the second conduit  122  is the suction. The direction of flow of the hydraulic fluid of the hydraulic pump  116  can be reversed using valving of the hydraulic pump  116  known to those in the art so that as a result the air flow of the blower  114  can also be reversed. 
     Accordingly, a significant advantage is that the speed and rotation of the hydraulic pump  116  can be varied, which thus controls the volume and direction of air from the blower  114 . More importantly, changing the flow of hydraulic fluid through the hydraulic pump  116  can be used to reverse the air flow in order to dislodge rocks that may be lodged inside the vacuum hose  111  and also can be used to pick up rocks out of a hole and drop them by stopping the air flow and vacuum. 
     Referring now to  FIG. 3 , a first gear box  128  may be coupled to the PTO shaft  122  and the first gear  128  box is configured to transfer power to the vacuum equipment  102 . Belts  130 ,  132  may be coupled to the first gear box  128 , where the belts  130 ,  132  drive additional auxiliary equipment such as the hydraulic pump  116  described above and a water pump  117 . The water pump  117  is in fluid communication with water tanks  110  that are carried by the truck  104 . The water pump  117  may include user operated controls configured to adjust an amount of water used during hydro excavation. 
     A second gear box  134  may also be coupled to the first gear box  132 , where the second gear box  134  may be configured to transfer power to an air compressor  135  used to generate high pressure air for the excavation process and break up soil. A frame  136  may be used to support and hold the blower  115  and the first and second gear boxes  128 ,  134  under the truck  104  in order to be in communication with the PTO shaft  122 , which is also under the truck  104 . 
     Referring now to  FIG. 4 , a method to drive vacuum equipment on a truck having an engine and a transmission includes coupling a power take-off (PTO) unit to a PTO port located on a side of the transmission, at  202 . The method also includes, at  204 , coupling a PTO shaft to the PTO unit. Moving to  206 , the method includes transferring power to the vacuum equipment mounted to the truck via a first gear box coupled to the PTO shaft, and driving additional auxiliary equipment via at least one belt coupled to the gear box, at  208 . In addition, the method includes driving a blower using a hydraulic pump coupled to the PTO unit, where the blower is configured to provide suction or discharge air flow to a vacuum hose in response to a direction of hydraulic fluid flowing through the hydraulic pump. 
     Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.