Abstract:
An eccentric adjustment and mounting system is useful for belt engaging engine components such as alternators or water pumps. The system includes a housing fixed to the engine, a socket rotatable in pawl-and-ratchet fashion within the housing, and a socket aperture eccentrically disposed relative to the socket&#39;s axis. The aperture receives the belt engaging component, whereby rotation of the socket moves the component to adjust belt tension.

Description:
GOVERNMENT INTEREST  
       [0001]     The invention described herein may be made, used, and licensed by, or for, the United States Government for governmental purposes without paying me any royalty. 
     
    
     BACKGROUND AND SUMMARY  
       [0002]     The present invention relates to an eccentric mounting and adjustment (EMA) system for belt driving or belt driven devices that are installed and operated within the restricted confines of an engine compartment, typically a motor vehicle. It satisfies two essential requirements for automotive devices driven by an endless flexible belt. These are: 1) a reliable mounting to the engine block assembly, and 2) a continuous provision of a proper amount of tension to the belt for either driving or driven devices. As a result, there is minimal wear and tear on device bearings and the belt, which reduces operational failures and assures maximum efficiency for these devices.  
         [0003]     The term “belt driven device” includes those devices within motor vehicles that are serviced by endless belts, such as power steering pumps, air compressors, water pumps, generators, alternators, cooling fans, sheaves, idlers, pulleys, water extraction and recycle systems, and other ancillary devices customarily used by motor vehicles with internal combustion engines. A drive device is one that is directly connected to an output shaft of said engine and uses a flexible endless belt to drive at least one driven device, such as an alternator.  
         [0004]     Further, a mechanic must avoid accidents while working in the restricted confines of an engine compartment to avoid any mishap to himself or to sensitive engine components. Such accidents could potentially disrupt or disable hydraulic, electrical, and mechanical systems located therein. Also, the mechanic or operator must perform all installation, adjustment, and removal work very quickly with minimal efforts and support in either the field or the shop. Finally, uncomfortable or awkward positions while working should be avoided to avoid personal injury.  
         [0005]     My invention allows any flexible belt of the armed forces&#39; inventory to be readily removable, installable, and adjustable by a single person using the simplest of tools, such as a large screwdriver, a pair of pliers, or an elongated rod of about ½ inch in diameter. Thereby, I have avoided former frustrations and expenses involving special tools or fasteners, which can be lost or misplaced. Moreover, minimal force and exertion are expended.  
         [0006]     Furthermore, this invention does not significantly modify or depart from standard procedures currently used by motor pools for maintaining belts, drives, and driven devices. For example, electrical connections are easily made by using a simple bayonet or coaxial connector that, in form, resembles the ends of modern “jumper cables” employed by the US Military, such that positive and negative poles are axially symmetric. Similarly, connections for mechanical or hydraulic systems are just as easily made by conventional methods at the rear of my invention.  
         [0007]     It is to be understood that the readiness requirements for military vehicles are unusual, and thereby necessitate more reliable and rugged designs than their commercial counterparts. The components must have a good tolerance for more frequent shocks, vibrations, and thermal events because they frequently go from prolonged periods at standing idle to wide open cross-country travel. Further, present art approaches have the potential for reducing readiness, increasing maintenance frequency and costs, as well as exposing personnel to undue risks to reattach or tension belts while engaged in awkward positions or extreme reaches.  
         [0008]     For military vehicles, belt performance is critical with regard to the tension that is maintained on them. With use, the belts can become loose and full torque is not easily transmitted to the driven devices. Thereafter, the belts can slip and become more damaged. If the belts are too tight, excessive wear can result in the bearing assemblies of the driving or driven devices as well as causing belt shredding or separation. This impacts operating efficiency.  
         [0009]     It is therefore an object of this invention to provide an EMA system that properly tensions an endless drive belt. It is a separate object to provide such a system that requires less manual force and effort while installing, tensioning, and operating. It is another object to provide a functional EMA system that is mechanically durable, economical to produce, reliable in construction, simple to manufacture, and capable of achieving a long or trouble free service life.  
         [0010]     These and other objects, features, and advantages of this invention will be apparent to those skilled in the relevant arts upon a full reading of this specification and the appended claims which explain and define the aspects and principals of this invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is an exploded perspective view of the eccentric mounting and assembly system of the present invention.  
         [0012]      FIG. 2  is an end view of the base housing member of  FIG. 1 .  
         [0013]      FIG. 3  is a side view of  FIG. 2 .  
         [0014]      FIG. 4  is a perspective view of the present invention mounted to an engine block assembly.  
         [0015]      FIG. 5  is an end view of the invention minus the driven device showing elastic bands and gripping pawls holding the socket in a secure, tensioned position.  
         [0016]      FIGS. 6 and 7  are perspective views showing greater detail of the gripping pawls of this invention. 
     
    
     DETAILED DESCRIPTION  
       [0017]      FIG. 1  depicts an eccentric mounting and assembly system  10 .  FIG. 4  shows a typical mounting of system  10  to a plate  70  on the engine block  68 , wherein the assembly is affixed to plate  70  by bolts passing through the system&#39;s rectangular base  18 . Plate  70  can be spaced from the engine block to allow clearance for electrical or fluid conduits passing from driven a device  56  through base  18 . An endless drive belt  74  rotates driven device  56  in conventional fashion. Besides device  56 , system  10  includes an eccentric socket  42  and a housing member  14 .  
         [0018]     Returning to  FIG. 1 , device  56  fits within receiving aperture  48  of socket  42 , which preferably is fashioned of a high-strength, heat resistant, non-metallic material. Device  56  is non-rotatably seated in socket  42  by the shape of the socket, or by alternate means, such as axial fixation within the socket by the use of wedges, lugs, flats, or pins. For instance, at least one lug  62  that extends outwardly from the circular surface of driven device  56  could be slidingly inserted within a conforming slot  50  of the internal wall of the eccentric socket  42 . Optionally, lug  62  and slot  50  can be angled so they effectively have a slightly spiraled or threaded engagement, such that rotation force exerted on device  56  by a drive belt screws the device into socket  42 , thereby seating the device in the socket.  
         [0019]     With reference to  FIGS. 1 through 3 , the housing member  14  includes a cylindrical portion  16 , having an open end  39 , with the opposite end of said portion fixedly attached to rectangular base  18 . The rectangular base has an annular resting surface  17  which defines central aperture  19 , which is smaller in diameter than cylindrical portion  16 . Aperture  19  provides ventilation while surface  17  provides a stop or rest for both socket  42  and driven device  56  within the socket.  
         [0020]     As seen in  FIG. 5 , automotive quality elastic bands, as at  41 , are placed about the cylindrical portion  16  so as to hold generally arcuate gripping pawls  20  thereon. Pawls  20  define arcuate channels  23  ( FIGS. 6 and 7 ) that accommodate bands  41  and prevent their escape from the pawls. Portion  16  is shown in section in  FIG. 5  so that it can be easily distinguished from the bands. Normally, each band will hold a set of two or more concentric, arcuate pawls on cylindrical portion  16  so as to retain the pawls in sets of complementary pawl slots, as at  28 ,  30  and  32 . The complimentary sets of slots and pawls are shown in  FIG. 1 . Teeth  27  of the pawls ( FIGS. 6 and 7 ) engage tooth-like elements on the outer periphery of socket  42  when the socket is inserted in housing member  14 . As with socket  42  it is expected that the pawls will be fashioned of a high-strength, heat-resistant, non-metallic material.  
         [0021]     The various pawls and slots in  FIG. 1  may be regarded as being in a three-by-three array, where apertures or slots  28  and the associated pawls are in the first row of the array. Slots  30  and their associated pawls are in the second row, and slots  32  and their associated pawls are in the third row. The three slots and pawls most distant from base  18  are in the first column, the next most distant slots and pawls are in the second column, and the slots and pawls closest to base  18  are in the third column. A given elastic band  41  retains pawls of one column in slots of that column.  
         [0022]     Pawls  20  can be retained by bands  41  or by a friction fit with their associated slots or by both means. Thus retained, the pawls hold socket  42  in housing member  14  by means of pawl teeth  27 , which mesh with or grip the socket&#39;s two gear-like annular regions  34  and  36 . Each of these regions comprises a multitude of teeth  46 . Teeth  46  have flat, relatively more radially oriented faces  45  alternating with relatively less radially oriented slopes  47 . Annular regions  34  and  36  are separated by an annular groove  40 . As desired for weight reduction or for cooling, socket  42  may be provided with apertures  54 , which may be cast, injected, or machined into the socket.  
         [0023]     Positioned approximately 60 degrees apart within groove  40  are adjustment holes  44 . When socket  42  is within housing member  14 , holes  44  align with slots  28 ,  30  and  32  in the second column in the array described above. Holes  40  receive tools which turn socket  42  within housing member  14  about its own axis  43  ( FIG. 5 ). Turning the socket clockwise moves device  56  to tighten belt  74  ( FIG. 1 ) due to eccentricity of the socket&#39;s receiving aperture  48 , which holds the device. The tools used for turning the socket can be very simple, such as a large screwdriver, a pair of pliers, or an elongated rod of about ½ inch in diameter that will fit into adjustment holes  44 .  
         [0024]     As eccentric socket  42  is turned clockwise with housing member  14 , one or more pawls  20  ratchet on each tooth  46 . When socket  42  reaches a suitable position, pawl teeth  27  lock with teeth  46 . In this position, socket  42  holds device  56  in a placement that maintains belt tension. The pawls may be held in position not only by band  41 , but also by friction fit with the pawl slots. The pawls will friction fit within one or more pawl slots  26 ,  30  or  32 , or a combination of these. Ideally each of the gear-like annular regions  34  and  36  will then be held in position by two or more pawls  20  gripping teeth  46 .  
         [0025]     In practice, not all the pawl slots will be filled by pawls. As little as two gripping pawls  20  are all that is necessary to hold the socket  42  in position as shown in  FIG. 5 . Some of the pawl slots can be left vacant to facilitate an immediate inspection of the sprocket  42 . Likewise, inspection can also be made of electrical or fluid connection elements(s)  52  between device  56  and engine block  68 .  
         [0026]     Additionally, it may be preferable that the pawl teeth  27  associated with one column not be angularly aligned with the socket  46  teeth of another column. For example, if the ratchet teeth  46  are every 6 degrees and the pawl teeth  27  are every 6 degrees, the first column (See paragraph 0021) will align the pawl teeth with ratchet teeth only every 6 degrees of rotation of the ratchet  42 . If, however, the second column is offset by (n×6)+2 degrees (n being an integer to determine the angular offset) and the third column is offset by another +2 degrees, the ratchet  42  teeth will be engaged every 2 degrees by one or another of the three columns. Thus, a three fold finer control of tension of the belts may be achieved.  
         [0027]      FIG. 6  shows further details of pawl  20  which mates with pawl slots  28 ,  30  and  32 . Pawls  20  have shoulders  21  whose undersides  25  rest on cylindrical housing  16  when the pawls are placed in their slots. Pawls  20  define frontal alignment notches  24 , which accommodate tabs  22  of the pawl slots. The notches and tabs prevent the pawls from being placed backwards in the slots. In alternate pawl  20   a  shown in  FIG. 7 , shoulder  25  has been extended rearward. This allows the rear of pawl  20   a  to be rested upon housing  16 . Pawl  20   a  is also modified to provide a pawl ridge  29  on its rear tooth  27   a . This ridge allows the pawl tooth to rest at a higher elevation on housing  16  which in turn raises the modified pawl tooth  27   a  further above the socket  42 . This higher elevation will limit any contact with the teeth  46  of socket  42  until pawl  20   a  is completely placed within a pawl aperture.  
         [0028]     Returning to  FIG. 1 , the pertinent features of the driven device  56  include a driven pulley  58  having cooling means  60  and a threaded mounting aperture  66  bored within one or more lugs  62  for the compatible receipt therein of a screw having complementary threading with aperture  66 . Said screw can operate in combination with assorted locking devices and washers that are ordinarily employed to assemble driven devices in the automotive industry.  
         [0029]     The main components of the cooling means  60  of driven device  56  include a fan  59  and a plurality of cooling apertures or vents  57 . At the rear of the driven device, an electrical output connector element  52  extends for mating with any compatible connector element. Typical connectors are a bayonet, spade, or coaxial connector that will connect to a complementary female acceptor coming from the engine block assembly. The connector mating is conventional and is not shown for simplicity within the drawings. Additionally, the driven device could be a water pump which would require conventional fluid connectors.  
         [0030]     I wish it understood that I do not desire to be limited to the exact details of construction or method shown herein since obvious modifications will occur to those skilled in the relevant arts without departing from the spirit and scope of the following claims.