Abstract:
A motor driven discharge chute control system for automatically controlling the lateral position of a concrete discharge chute associated with a transit mixer vehicle is disclosed including a reversing motor connected to an output gear normally engaged to rotate with the motor through a gear reducer. A rotating chute swing gear is driven by the output gear and rotates a connected pivot assembly that carries one end of a discharge chute. A manual override system is also provided.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to transit mixing concrete hauling vehicles and particularly to rear discharge types which include an appended discharge chute capable of lateral directional displacement to direct discharge of concrete in a desired direction. Specifically, the invention is directed to a mechanized chute control system to automatically and controllably rotate and position of the chute as desired. 
     II. Related Art 
     Concrete transit mixing or ready-mix trucks are widely used in the construction and paving industries for preparing and transporting concrete mixtures to desired construction sites where the concrete is discharged into prepared forms or other carriers. Discharge is normally accomplished by reversing mixing drum rotation so that concrete spills from the top drum charging opening. In order to guide concrete to prepared forms, equivalent molding structures, or other receiving containers, mixing trucks in commercial use today typically employ a main discharge chute having an ability to pivot both vertically and laterally. A chute may or may not have one or more extensions. In order to withstand stresses which are created by the discharge of heavy wet concrete (approximately 4,000 pounds or 1800 kg per yard), discharge chute components need to possess a great deal of strength and are typically made of rather heavy gauge trough-shaped metal segments. 
     The position of the chute typically must be adjusted often during discharge operations. Vertical adjustment is accomplished with the help of attached hydraulic cylinders, however, lateral operation of the chutes has been accomplished through manual positioning and the weight of the chute and the concrete material makes the positioning difficult during use. Additionally, chute operation requires virtually the full-time attention of one crew member who could more advantageously be accomplishing other tasks. 
     FIG. 1 presents, in schematic perspective illustration, a typical environment or context for which the present invention is designed. In that figure, a rear discharge transit mixer vehicle is depicted discharging concrete to one side of the truck. The truck generally designated  10  is supported as by wheels  12  connected by an axle assembly  14  mounted to a body frame  16  through a heavy duty suspension system  18 . The transit mixing vehicle also includes a mixing drum  20  and a hopper for charging materials to be mixed at  21 . The conventional discharge chute system includes a dispenser  22  which passes concrete from opening  23  through a transition segment  30  to an inclined chute system  24 , including one or more U-shaped sections  26  tapering to a distal discharge end  28 . 
     Elevation or vertical pivoting of the chute sections  26  is controlled and powered by a pair of fluid operated cylinders  36  and  38  linked thereto in a manner that also enables free rotation of the chute from side to side. This operation is typically manual and so, together with mechanized height adjustment, enables cement  40  to be placed in the desired location as at  42 . 
     Once positioned, an air-operated chute lock is usually used to hold the chute in place. Additionally, a manually operated spring latched handle lock which uses a pin to align holes in moving and stationary parts may also be used. 
     Whereas prior systems have been successful, drawbacks include the need for constant attention by operating personnel in unlocking, making lateral adjustments and re-locking the chute in place. In addition, the chutes are heavy and, as is well known throughout the industry, care must be taken in the manipulation of such devices particularly during discharge operations. Accordingly, there remains a need for a hands-off mechanized system to automatically control the lateral positioning of the chute, to free an operator for other tasks and to provide better chute disposition control. 
     SUMMARY OF THE INVENTION 
     The present invention provides controlled motorized operation of the swivel or lateral chute swinging function of concrete discharge chute operations and is susceptible of remote or local control. The chute control system of the invention allows a full 180°+ lateral chute deployment range and provides inherent positive locking at all positions using an engaged transmission. A freewheeling manual override mode is included and a conventional latch lock is also provided. The system is designed to be compatible with many existing manual systems as a retrofit upgrade. 
     The system includes a fluid operated (preferably hydraulic) reversing motor connected to drive a suitable gear speed reduction and transmission system which includes a drive gear that engages a rotating chute swing plate gear which predicts and controls chute side-to-side orientation in response to operation of the motor. The system gears remain engaged after operation of the motor and this provides one positive locking mechanism. A manual spring-biased shaft latch lock also can be engaged. The gears can be disengaged to provide a manual or freewheeling override when desired. It is contemplated that the motor can be operated remotely from the cab of the truck or locally with controls at the rear of the vehicle. 
     This summary of the invention is intended not to limit the claimed subject matter, the scope of the invention being broader than any particular example and defined by the attached claims and their equivalents. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other features and intended advantages of the invention will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings in which: 
     FIG. 1 shows a schematic perspective representation of a typical transit readymix truck having a manually operated swiveling discharge chute; 
     FIG. 2 is an exploded view of an embodiment of the chute control system of the invention; 
     FIG. 3 is a view of the system of FIG. 2 in an assembled state; 
     FIG. 4 is a schematic view partially in section showing a drive system for the embodiment of FIGS. 2 and 3; and 
     FIG. 5 is an exploded view of additional parts of the arrangement. 
    
    
     DETAILED DESCRIPTION 
     The present invention automates and improves the maneuvering of a discharge chute of the type which is adapted for guiding a concrete mixture from a discharge end of a concrete mixing truck to a desired location. This adds side-to-side control to chute elevation control which has been accomplished utilizing attached hydraulic cylinders for some time. The system of the invention adds ease and accuracy to the horizontal aspect of discharge point location without sacrificing any of the manual capabilities. The exemplary embodiment detailed in the following description is one which is designed to be compatible with and easily retrofit onto many existing models, particularly models of those manufactured by applicant&#39;s assignee. 
     With reference now to the drawing figures, the chute control mechanism is shown partially exploded in FIG.  2  and includes a stationary A-shaped bearing pivot frame  50  which is fixed to a heavy support frame carried by the truck chassis in a well known manner (not shown). This frame also supports a charging hopper above the discharge system. The bearing pivot frame  50  includes a pair of shaped structural frame members  52  and  54  which are jointed at a common tube member  56  which, in turn, describes a central bore  58 . A top mounting plate  60  is fixed to the structure. 
     A hydraulic motor is partially shown at  144  connected to a lower gear housing  64 ; a mounting plate  66  and an upper gear housing  68  with front opening  70  are also part of the drive mechanism. A clutch lever  72  for disengaging the drive and allowing free wheeling of the discharge chute is shown pivotally mounted at  73 . The plate  66  is designed to fix the drive components to the frame members  52  and  54 . These components remain in a fixed position relative to the truck chassis at all times. 
     The rotating portions of the delivery chute control system include a chute swing gear member  74  and a rear pivot assembly  76  which includes a mounting plate  78  designed to carry the swing gear member  74  using concentric mounting holes  80  (FIG.  3 ). The rear pivot includes a pair of heavy mounting brackets  82  for carrying a chute (not shown) in vertically pivoting relation thereto. A bearing shaft  84  is designed to be journaled in the central bore  58  so that the rear pivot assembly with the swing gear  74  are freely rotatable with respect to the fixed frame  50 . The rear pivot assembly  76  also includes a stiffener plate  86  and a plate  88  having a series of spaced radially distributed holes  90  which align and misalign during rotation with a hole  92  in the stationary member  60 . These aligned holes are used in conjunction with a manual locking system which will be described. 
     The pivoting or swing assembly details are further shown in the reduced exploded perspective view of FIG.  5 . That view includes a bearing assembly associated with the bearing shaft  84  including a pair of bearing cups  102  adapted to contain cone swivel bearings  104  flanked by seals  106 . Also carried by the shaft  84  are a spacer  108  and a chute cylinder mounting clevis  110 . The assembly is secured by a pivot bottom plate  112 , member  113  and a locking nut  114 . A chute pivot or lift cylinder which may be single or double acting is pictured at  116 . Connections are conventional. 
     Also pictured in FIG. 5 is a manual pivot lock assembly  120  which includes a lock handle  122  with locking member  124 . A latch spring  126  with washer  128  and roll pin  130  are also pictured with associated lock housing  132 . Lock housing  132  also carries a radial hole  134  which aligns with the opening  92  in the member  60 . When the pivot lock housing is fixed to the member as by bolting through adjacent spaced openings  136  and  93 . 
     FIG. 4 is a side elevational schematic view partially in section through the power drive system. The system includes a hydraulic motor  144  (FIG. 2) having an output shaft  146  keyed to a worm gear shaft  148  which is the input to a speed reducer or gear box  64 . A worm gear which enmeshes with and drives a first planetary gear  150  which also has an inner ring gear aspect  152  which engages a second planetary gear member  154 , in turn, keyed to one end of a main drive shaft  156 . The main drive shaft  156  further carries toward its other end a drive gear  158  which, in turn, engages the chute pivot or swing gear member  74 . The shaft  156  is displaceable downward axially utilizing the clutch lever  72 , but is normally forced upward by a spring at location  160 . This results in the normal engagement of the gears  150  and  154 . As can be seen, rotation of the worm with the elements in the relation pictured results in rotation of the chute swing gear member  74  at reduced speed thereby laterally displacing the rear pivot assembly and attached chute left or right as desired. 
     In operation, the automated mechanized system of the invention can be readily connected for remote activation as from the truck cab or by activation at the rear of the vehicle near the chute in a well known manner. Operation is normally by push-button so that upon the release of the button when the desired relative lateral position is reached, movement of the chute will stop and as the gears remain engaged, the chute positioned in this manner will remain securely in place. The latch system  120  can also be employed to aid in locking the manual chute in position assuming it stops with the proper holes aligned. It will be recognized that a stepping motor or the like may also be used to drive the positioning system. In this manner, angular positioning of the concrete discharge chute relative to the truck is accomplished and adjusted as necessary readily and without the need to engage a worker who can be otherwise occupied with the distribution of the concrete. 
     A manual override is also available using the clutch lever  72  to disengage the drive system and allow manual freewheeling adjustment of the chute if desired so that this option remains available. Upon release of the lever  72 , the gears will re-engage holding the chute position. The swing gear member  74  is preferably toothed through a full 180° so that a full 180° automated swing range is provided. Of course, the clutch system could also be detanted or operated by a motor or by a fluid cylinder as well. Mechanization would allow an operator to keep a greater distance from gears and other moving parts. 
     This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the example as required. However, it is to be understood that the invention can be carried out by specifically different devices and that various modifications can be accomplished without departing from the scope of the invention itself.