Abstract:
A driveshaft containment system and a method of its use. In preferred embodiments, the invention takes the form of a two component system including a first component mounted to a device such as a differential housing, coupled to driveshaft, and a second component comprising a tubular driveshaft containment housing. A driveshaft containment ring is preferably mounted to the forward end of the tubular housing which in turn is provided with a mechanism at its rearward end for rotationally engaging and disengaging the first component. The first and second components are also provided with a mechanism for preventing relative rotational movement of the first and second components while engaged with one another.

Description:
RELATED APPLICATION 
     This application claims priority from U.S. provisional Patent Application No. 61/463,389 for a Driveshaft Containment Device, by Paul Pittman, filed Feb. 26, 2011, incorporated herein by reference in its entirety. 
    
    
     FIELD 
     This invention generally relates to a device for containing a vehicle drive shaft in the event of a failure of a universal joint. The invention relates particularly to containment of the portion of a driveshaft adjacent to a differential or other driveline housing in a motor vehicle. 
     BACKGROUND 
     It is known to provide containment loops at the forward and rearward ends of drive shafts in motor vehicles to retain the ends of the drive shafts in the event of failure or breakage of a universal joint. The NHRA (National Hot Rod Association), in particular, mandates the use of both front and rearward driveshaft containment loops in several classes of vehicles used for quarter mile drag racing. A wide variety of designs of such loops are currently available. In particular, those manufactured or sold by Scribner Welding and Distributing, Mark Williams Enterprises and Jerry Bickel Race cars, Inc, take the form of loops mounted to and completely supported by the forward portion of the differential housing or carrier (the terms are used interchangeably herein). These devices are also known as “rearward driveshaft enclosures”. 
     Such devices typically comprise a ring-shaped flange attached to the front of the rearward differential housing at several points around its circumference. In some designs, the device includes a tubular shield extending forward of the differential housing and surrounding the adjacent universal joint. A containment loop is typically provided located somewhat forward of the universal joint, at the forward end of the tubular shield (if provided). The loop may be coupled to the flange by means of a set of tubes extending rearward to the flange. Alternatively, the flange may be provided with forward extending projections which are coupled to the side of the tubular housing or the tubular housing may be provided with a second flange at its rearward end, coupled to the flange on the driveshaft housing. These designs generally employ multiple separate connector mechanisms associated with various attachment points located spaced around the circumference of the flange attached to the driveshaft housing. 
     SUMMARY OF THE INVENTION 
     In the context of drag racing, it is sometimes necessary to disconnect the driveshaft from and reconnect the driveshaft to the same or a substitute differential between successive races during a single event. Time between successive rounds can be short, and many other tasks may also need to be performed. To this end, the ability to quickly and simply remove and replace these rearward driveshaft enclosures is desirable in order to make best use of the available time. The present invention is directed toward accomplishing this desired result without compromising structural integrity of the driveshaft enclosure as mounted. 
     The present invention accomplishes the above desired result by providing a driveshaft enclosure which provides a first plurality of multiple attachment locations arrayed around the forward end of the differential housing to ensure structural integrity while only requiring disconnection of a lesser number of connector mechanisms and/or performance of a lesser number of disconnection operations to release the enclosure from the differential housing. 
     In preferred embodiments, the invention takes the form of a two component system including a first component mounted to the differential housing and a second component comprising a driveshaft containment ring. The driveshaft containment ring is preferably mounted to the forward end of a tubular housing which in turn is provided with a mechanism at its rearward end for rotationally engaging and disengaging the first component. The first and second components are also provided with a mechanism for preventing relative rotational movement of the first and second components while engaged with one another. 
     In a preferred embodiment, various versions of the first component are available, each having a configuration adapted for use with a specific type of differential housing or carrier. However, the rotational engagement mechanism of the first and second components is preferably the same for each of the first components, whereby a single configuration of the second component is usable with all versions of the first component. By this arrangement, a user may purchase individual first components for each of several differential housings, while only needing to purchase a single second component, usable with all. By this means, expense associated with the replacement or exchange of differential housings can be correspondingly reduced. 
     In a preferred embodiment, the first component takes the form of a generally ring-shaped flange mountable to the front portion of a differential housing or case, typically by means of bolts or nuts arranged to mount to corresponding pre-existing threaded bores in or studs extending from the font portion of the differential housing. To this end, the flange will typically be provided with a plurality of holes at locations extending around the flange and aligned with the threaded bores or studs of the differential housing. In some cases, it is understood that additional bores or studs may have to be provided on the housing, if needed to provide structural rigidity. 
     The first component (flange) is also preferably provided with a series of slots arrayed in a circular pattern extending around the flange. The rearward end of the tubular housing of the second component is preferably provided with a corresponding series of tangs, insertable within the slots. The tangs are preferably formed as integral extensions of the tubular housing. Each tang has a base that extends rearward from the tubular housing a free end that extends circumferentially, clockwise or counterclockwise, for distances less than or equal to the corresponding lengths of the slots. By this mechanism, the tangs may be simultaneously inserted into the slots and, with only a slight rotation of the tubular housing thereafter, the second component is simultaneously engaged with the first component at a plurality of locations to provide structural integrity. 
     After rotation of the tubular housing into engagement with the flange (rotational engagement of the first and second components) the first and second components are further engaged with each other to prevent unintentional counter rotation and disengagement of the components. In preferred embodiments this is accomplished by means of a single fastening mechanism which rotationally fixes the tubular housing relative to the flange. Preferably, this mechanism is located generally on the top center portion of the containment device as installed, so that it may readily be accessed from either side of the car optionally through an access opening through the floor of the car, provided, for example, by means of a removable panel 
     In addition to simplicity of installation and removal, the preferred embodiment discussed above provides a savings in over-all weight, due to the fact that the tubular housing itself includes the mechanisms (tangs) for attachments to multiple locations around the flange, without the necessity of additional structures such as tubes, additional flanges, extensions from the flange, nuts, bolts and the like. Fabrication of the device is also correspondingly simplified. The preferred embodiment also thus also minimizes the number of removable components (nuts, bolts and the like) which might be misplaced during sometimes hectic activity between successive rounds of racing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects and features of the present invention will be appreciated as the same becomes better understood by reference to the following detailed description of the embodiments of the invention when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a side view of a differential assembly of one type appropriate for use with the present invention 
         FIG. 2  is a side view of the differential assembly  FIG. 1  with a preferred embodiment of the invention attached thereto. 
         FIG. 3  is a plan drawing of the sheet of metal used to fabricate the tubular housing of the present invention. 
         FIG. 4  is a plan drawing of first embodiment of a flange according to the present invention. 
         FIG. 5  is a plan drawing of second embodiment of a flange according to the present invention. 
         FIG. 6  is a perspective view of a preferred embodiment of both components of the present invention, un-assembled. 
     
    
    
     DETAILED DESCRIPTION 
     In the figures as described below, numbered components on each drawing correspond to identically numbered components on the other drawings. All numbered components will not be described separately for each figure. 
       FIG. 1  is a side view of a differential assembly  10  of one type appropriate for use with the present invention. The input shaft  12  can be seen extending forward of the differential housing  14 , carrying one yoke  16  of the universal joint which couples the input shaft  12  to the rear end of the driveshaft (not illustrated). 
     The forward surface of the differential housing is provided with a plurality of bolts  18 , distributed in corresponding threaded bores circumferentially around the forward surface of the housing  14 , encircling the input shaft  12 . In some preferred embodiments, these bolts or longer, substitute bolts are used to secure the flange of the present invention to the differential housing. In alternative embodiments, the differential housing may be provided with forward extending studs, with corresponding nut used to secure the flange. If the forward surface of the differential housing is not provided with bores or studs, the flange may optionally be provided with rearward extensions to engage side surfaces of the differential housing. 
       FIG. 2  is a side view of the differential assembly  FIG. 1  with a preferred embodiment of the invention attached thereto. In this view, the flange  100  is secured to the front surface of the differential housing  14  by means of the bolts  18  ( FIG. 1 ). The tubular housing  102  extends forward from the flange, terminating at its forward end with the containment loop  104 . Tangs  106  are visible extending through corresponding slots in flange  100  and retain the tubular housing to the flange as discussed above. 
     An outwardly extending tab  108  is secured to the tubular housing  102  and is aligned with a corresponding tab on the flange  100  when the tubular housing is rotated into engagement with the flange as described above. A nut and bolt  110  are shown extending through corresponding bores through the flange  100  and the tab  108 , rotationally fixing the tubular housing with respect to the flange. The tabs on the flange and tubular housing are shown as extending upward from the assembly, located generally centrally as discussed above to allow access from both sides. The nut and bolt  110  may be replaced with another type of fastener, such as a quick release pin or the like. 
     The containment loop  104  may be fabricated, for example, of chrome-molly alloy steel, and may take the form of two semi-circular segments of ⅞″ OD, tubing, welded end to end to provide a loop of approximately 7″ in outer diameter. The loop is then welded to the forward end of the tubular housing. Dimensions and materials of course may be altered and optimized to suit particular applications. The specific example described herein is merely exemplary. Similarly sized components of titanium, for example, may be substituted. 
     As illustrated, the containment loop is located forward of the universal joint coupling the driveshaft to the input shaft  12  ( FIG. 1 ), so that in case of failure of the universal joint, the rearward end of the driveshaft will be retained within the loop. 
       FIG. 3  illustrates the sheet  200  of metal from which the tubular housing is manufactured. This sheet may also be fabricated of chrome-moly alloy steel or other suitable material. The tangs  106  are seen extending from the edge  202  of the sheet  200  that will form the rearward edge of the tubular housing. The tangs are preferably formed integral with the sheet, for example by cutting the sheet as illustrated from a larger sheet by laser of plasma cutter or other appropriate mechanism. The sheet is then rolled into the form of a tube, with edges  204  and  206  welded to one another. Edge  208  forms the forward edge of the tubular housing and is welded circumferentially to the containment loop as described above. While a tubular housing formed of a single rolled sheet as described herein is the preferred embodiment, a tubular housing formed of multiple individual tubes or rods as employed in some prior art rearward driveshaft enclosures may be substituted in some cases. 
     The sheet  200  as shown is sized to provide a tubular housing of approximately 6″ in diameter and 6″ in length. Dimensions and materials of course may be altered and optimized to suit particular applications. The specific example described herein is merely exemplary. As shown, the sheet is provided with five tangs  106 , but this number may also need to be to be altered to allow optimization for particular applications. 
     In some embodiments, the tubular housing may be provided with an opening though which a sensor (e.g. speed sensor) or conductors associated therewith may extend. This opening (not illustrated) is preferably takes the form of a slot or notch in the rearward edge of the sheet, so that the sensor may remain attached when the tubular housing is detached from the flange. The slot or notch may conveniently be located to that it resides at the 9:00 position as viewed from the front of the assembled device. 
       FIG. 4  is a plan view of a first embodiment of a flange  300  according to the present invention, corresponding to flange  100  ( FIG. 2 ). The flange may also be fabricated of chrome-moly alloy steel or other suitable material. As illustrated, the flange is provided with five bores  302  extending therethrough allowing for attachment to the forward surface of a corresponding differential housing provided with five bolts or studs. Five slots  304  are also illustrated, arranged to allow insertion of the tangs  106  ( FIGS. 2 and 3 ) as discussed above. Tab  306  extends outwardly from the flange also provided with a bore therethrough. Tab  108  ( FIG. 2 ) is welded to sheet  200  ( FIG. 3 ) after it is welded to form a tube and in a location such that the bore therethrough aligns with the bore through tab  306  after rotation of the tubular housing  102  ( FIG. 2 ) into engagement with the flange, as discussed above. 
       FIG. 5  is a plan view of a second embodiment of a flange  400  according to the present invention, corresponding to flange  100  ( FIG. 2 ). The flange may also be fabricated of chrome-moly alloy steel or other suitable material. As illustrated, the flange is provided with twelve bores  402  extending therethrough allowing for attachment to the forward surface of a corresponding differential housing provided with five bolts or studs. Five slots  404  are also illustrated, arranged to allow insertion of the tangs  106  ( FIGS. 2 and 3 ) as discussed above. Tab  406  extends outwardly from the flange also provided with a bore therethrough. Tab  108  ( FIG. 2 ) is welded to sheet  200  ( FIG. 3 ) after it is welded to form a tube and in a location such that the bore therethrough aligns with the bore through tab  406  after rotation of the tubular housing  102  ( FIG. 2 ) into engagement with the flange, as discussed above. 
       FIG. 6  is a perspective view of the containment device components, unassembled. 
     While the preferred embodiment as disclosed herein is adapted for use in containing the rearward universal joint adjacent the differential, the device may also be adaptable for use in other locations, adjacent other driveline devices such as the rear end of a transmission or the like. As such, the above disclosure should be considered exemplary of the invention as claimed below. 
     In conjunction with the above disclosure, I claim the invention as set forth below.