Abstract:
An automatic transmission brake adapter for use in high performance vehicle drag racing. In electronic controlled automatic transmission, the transmission is held in both reverse and drive allowing the engine to accelerate without movement of a vehicle. Release of the reverse gear and associated rapid acceleration of the vehicle in drive is accomplished by a modular transmission brake adapter using the existing electronic automatic transmission control system without extensive modification thereto.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   This invention relates to transmission brakes for vehicles in which the transmission is held in place by engaging both drive and reverse gears simultaneously allowing the engine to be accelerated without moving the vehicle until the reverse gear is released. Such devices are used in high performance automobile drag racing in which it is important to get the fastest start possible when utilizing an automatic electronic controlled transmission. 
   2. Description of Prior Art 
   Prior art devices of this type have been directed to a variety of ways in which automatic transmissions can be selectively locked into a braking position for drag racing purposes when released, see for example U.S. Pat. Nos. 4,883,151, 5,148,720, 5,622,088 and 6,050,384. 
   In U.S. Pat. No. 4,883,151 a transmission brake is disclosed for automatic transmissions in which the conventional gear selector is modified in the vehicle with two gear engagement positions by modifying the existing manual selecting switch shift valve. 
   U.S. Pat. No. 5,148,720 discloses a lock-up solenoid assembly that is universal that closes off a fluid passageway allowing pressure to build up in a control chamber moving a valve element so that the front portion of the torque converter can empty itself, effectively locking the transmission. 
   An automatic transmission for racing is set forth in U.S. Pat. No. 5,622,088 which has a reverse gear piston that is engageable to act as a transmission brake. 
   U.S. Pat. No. 6,050,384 is directed to a method and device for rapid transmission brake release in which a modification to the automatic transmission is made applicable to Turbo Hydromatic 400 Transmissions. A pressure release passageway is provided in the servo cover so that it can be selectively blocked and unblocked by a solenoid. 
   SUMMARY OF THE INVENTION 
   An automatic transmission brake for use on electronically controlled automatic transmissions for high performance drag racing vehicles which allows for modification by use of a modular controller unit that is added to the existing electronic shift valve body. Electronically controlled transmissions can therefore be modified maintaining the use of the CEM computer controlled shift body while providing for an integrated transmission braking by engaging both drive and reverse gear simultaneously then instantaneously disengaging the reverse gear allowing for acceleration of the vehicle under high engine R.P.M.&#39;s without effecting the electronic control of the transmission. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a sectional view on lines  1 - 1  of  FIG. 2  showing the transmission brake control insert of the invention; 
       FIG. 2  is a front elevational view of the invention; 
       FIG. 3  is an enlarged partial sectional view of the control valve of the invention in unlocked position; and 
       FIG. 4  is an enlarged partial sectional view of the control valve of the invention in locked drive position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to  FIGS. 1 and 2  of the drawings, a transmission brake  10  of the invention for use in electronically computer controlled automatic transmissions that use manifold type sensor fluid control switch as is well known and understood within the art. The transmission brake  10  of the invention is of a modified modular configuration that is installed within the transmission valve body  11  shown graphically in broken lines with the existing manifold sensor plate  11 A shown graphically in broken lines reinstalled thereover via alignment of multiple bolt apertures  12  and inclusive mounting bolts (not shown). 
   A control body member  13  has a plurality of control fluid inlet and outlet portals generally referred to at  14  with interconnecting communication fluid pathways generally indicated at  15 . 
   A cylinder control valve chamber  16  is formed within the main body member  13  and is in communication with control fluid pathway ports  17  for a drive and reverse gears activation thereof as will be explained in greater detail hereinafter. 
   A shuttle valve element  18  is movably disposed within the valve chamber  16  controlling the flow between the pathway ports  17  and is engaged by a spring  19  at one end thereof. A control solenoid  20  in oppositely disposed relation to the spring  19  is in communication with the valve chamber  16  via control portal  21  and valve needle  20 A movably thereby for selectively sealing a portion of the chamber  16 A defined by the effacing end  18 A of the shuttle valve element  18 . The shuttle valve element  18  has an oppositely disposed spring engagement seat  22  and a central area of reduced annular diameter at  23  and a plurality of annular ring gasket seals  24  on the valve body in spaced relation thereto as required to maintain a sealing relationship therewith. 
   Referring to  FIGS. 2 and 3  of the drawings, an enlarged valve control sectional view can be seen wherein the solenoid control port  21  and valve needle  20 A is shown graphically for illustration purposes for the understanding of the control valving sequence of the system during use. 
   The solenoid valve  20  is in electrical communication via an electrical circuit  25  to a transmission brake activation button  26  as seen in  FIG. 1  of the drawings. The transmission brake activation button  26  is interconnected in the electrical circuit  25  through an electronic pressure switch  27  that assures that the transmission brake of the invention cannot be engaged when the transmission is in overdrive for best performance as will be well understood by those skilled in the art. The pressure switch  27  is therefore in fluid communication with an overdrive fluid portal indicated at  27 A as best seen in  FIG. 1  of the drawings. 
   In operation, the electronically controlled automatic transmission will operate in a normal manner with the control solenoid  20  deactivated as seen in  FIG. 3  of the drawings in which the fluid control pathway ports  17  specifically the “from” the reverse gear pathway  28 A and the “to” reverse gear pathway  28 B are in communication with each other as indicated by flow arrows A. The solenoid  20  prevents pressure build-up in the chamber portion  16 A which is in non-restrictive communication with drive fluid via an inlet port  29 . 
   Once activated by the transmission brake activation button  26  the solenoid  20  seals the chamber portion  16 A by engagement of the valve needle  20 A within the solenoid control port  21  thereby pressurizing the chamber  16 A driving the shuttle valve element  18  against the resilient spring  19  allowing control fluid to flow to both the drive gear by the drive port  30  and “to” reverse gear port  28 B effectively locking the electronic control transmission in both reverse and drive gears as shown by flow arrows B as seen in  FIG. 4  of the drawings. 
   Upon deactivation of the solenoid  20  the pressurized valve chamber portion  16 A is vented again by opening the solenoid control port  21  and the spring urged shuttle valve element  18  returned to its first position, releasing reverse gear so that the vehicle (not shown) accelerates rapidly forward in “drive” at the established high R.P.M.&#39;s as seen in  FIG. 3  of the drawings. 
   It will be seen that the transmission brake  10  of the invention has a plurality of communication portals  31  shown in broken lines in  FIG. 2  of the drawings that will interengage and communicate with existing corresponding fluid control passageways in the electronic transmission manifold  11 A as seen in broken lines in  FIG. 2  of the drawings which will allow for an effective and simple installation of the automatic transmission brake  10  of the invention without extensive modification to the existing transmission valve body. This assures full normal operation of the electronically controlled automatic transmission with the advantage of a true automatic transmission brake which is critical in the sport of drag racing as outlined above and understood by those skilled in the art. 
   It will thus be seen that a new and novel transmission brake for electronically controlled automatic transmissions for use in drag racing has been illustrated and described and it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.