Abstract: A multiple substantially identical countershaft powershift transmission is provided. The transmission (10) comprises an input shaft (12) and preferably three (16, 18 and 20) input gears and an output gear (22) concentric and rotatable relative thereto. A plurality of substantially identical countershaft assemblies (42, 42A) carrying countershaft gears (54, 56, 58 and 60) constantly meshed with the input gears and output gear surround the input shaft and an output shaft (24) generally coaxial with input shaft (12) and carrying the output gear (22) rotationally fixed thereto are provided. A first double acting friction clutch mechanism (26) for selectively frictionally coupling first speed input gear (16) or third speed input gear (18) to the input shaft and a second double acting friction clutch mechanism (28) for selectively coupling second speed input gear (20) or fourth speed output gear (22) are provided and are concentric and driven by the input shaft (12).

Abstract: A multiple substantially identical countershaft (16, 16A), simple change gear transmission (10) having two-piece (20, 20A, 22, 22A) countershafts is provided. The use of two-piece countershafts allows the countershafts to be supported by three bearings (72, 74 and 76) while not requiring greater than normal manufacturing accuracy of the transmission housing (H). A driving connection between the front and rear countershaft portions is utilized which will allow a degree of axial misalignment between the front and rear portions and which when connected assures proper circumferential alignment of the countershaft gears.

Abstract: An improved, blocked, change gear transmission utilizing at least one improved resilient jaw clutch assembly to selectively engage a selected gear to a shaft is provided. The improved jaw clutch assembly comprises two axially engageable jaw clutch members and a blocker mechanism to prevent engagement of the jaw clutch members until the jaw clutch members are rotating at a substantially synchronous speed. Preferably, one of the jaw clutch members carries axially and radially outwardly extending external clutch teeth designed for selective interengagement with axially and radially inwardly extending internal jaw clutch teeth carried by the other jaw clutch member. The improvement comprises providing a back-lash between the interengageable clutch teeth which is substantially greater than the back-lash normally utilized with similar clutch assemblies, said increased back-lash being in the range of five to fifteen times greater than normal back-lash and preferably about ten times greater than normal back-lash.

Abstract: An improved shiftable change speed transmission is provided. The improved transmission is preferably provided with at least one countershaft having countershaft gears thereon disposed in meshing engagement with main shaft gears encircling the transmission main shaft. Gears are selectively axially movable relative to the associated shaft by conventional means for effecting shifting of the transmission. The axially movable gears cooperate with clutch rings which surround and are supported on and for rotation with the associated shaft by splines, preferably the clutch rings also are axially movable relative to the associated shaft and are resiliently urged in a direction toward the respective gear with which same cooperates, whereby shifting of the axially movable gear toward its respective clutch ring causes resilient axial movement of the latter until synchronization is achieved to permit the clutch ring to move axially in response to said resilient urging and engage the main shaft gear.

Abstract: An improved, blocked, change gear transmission having an input shaft driven by a prime mover through a normally engaged, selectively disengageable, master friction clutch is provided with means for decelerating and positively reverse rotating the transmission input shaft. The means for decelerating and positively reverse rotating the transmission input shaft may be selectively operator actuated and/or automatically actuated. The means for decelerating and positively reverse rotating the transmission input shaft is preferably only actuatable upon disengagement of the master clutch and may be selectively or automatically actuated by the master clutch control.

Abstract: A mechanism for selectively and/or automatically decelerating and positively reversing the normal direction of rotation of a rotatable shaft is provided. The mechanism includes a member which is meshingly engaged to a shaft driven by a one-way drive, such as the input shaft of a change gear transmission driven by a Diesel engine, and is operable to decelerate the shaft and positively rotate the shaft in the opposite direction of rotation.

Abstract: An improved, blocked, change gear transmission having an input shaft normally driven by a one-way prime mover and an output shaft normally connected to a driven device is provided. The transmission utilizes at least one improved blocker and jaw clutch assembly which allows engagement of a selected ratio gear under static conditions, i.e., when the driven device is at rest and the blocked transmission is in neutral.

Abstract: Improved blocker and jaw clutch means for shiftable change speed gearing is provided for effecting engagement of the low speed gearing of a simple transmission, or the low speed gearing of the main transmission section of a splitter type compound transmission. A transmission having an input shaft driven by a one-way prime mover, a main shaft and at least one countershaft, and including pairs of shiftable gears arranged on and cooperatively between said shafts, is provided with positive clutches, preferably spring loaded jaw clutches, for effecting connection to one of said shafts of a selected one gear of a selected one of said pairs of said gears upon the achievement of substantial synchronization between such gear and such shaft. Blockers are provided for protecting the positive clutch teeth from excessive wear during such shifting.

Abstract: Improved change speed gearing utilizing an improved blocker means for effecting engagement of the jaw clutch associated with the low speed gearing of a simple transmission, or with the low speed gearing of the main transmission section of a splitter type compound transmission. A transmission having an input shaft driven by a one-way prime mover, a main shaft and at least one countershaft, and including pairs of shiftable gears arranged on and cooperatively between said shafts, is provided with positive clutches, preferably spring loaded jaw clutches, for effecting connection to one of said shafts of a selected one gear of a selected one of said pairs of said gears upon the achievement of substantial synchronization between such gear and such shaft. Blockers are provided for protecting the positive clutch teeth from excessive wear during such shifting.

Abstract: Transmission and engine control means for a vehicle wherein the engine is connected through at least one friction clutch to a transmission having a positively geared power train therethrough. A low speed governor is provided to sense an engine speed at or shortly below idling speed and functions to increase fuel supply to the engine as same is lugged down for maintaining, within the capacity of the engine, at least said selected minimum speed. Further, means are provided responsive to the position of the throttle control, such as the accelerator pedal, for modulating the engagement pressure of said clutch in response to the position of such throttle control, progressive opening of the throttle effecting progressive increase in the torque transmitting capacity of the clutch, whereby the torque transmitting capacity of the clutch is under all throttle settings maintained at a value a little greater than the load torque normally applied thereto at such throttle setting.

Abstract: Improved mainshaft gear retainer means for a twin countershaft transmission having floating mainshaft gears positioned close together in groups of two and clutchable to a mainshaft one at a time by positive clutches which each have splines mateable with splines defined by each gear. The improved mainshaft gear retainer means prevents axial movement of two closely positioned gears and includes a snap ring axially interconnecting the gears, a thrust ring interposed between the axially interconnected gears, and a snap ring carried by each axially interconnected gear.

Abstract: Shiftable gearing including spring loaded means and blocker means for effecting engagement of clutch teeth. In a transmission having a main shaft and at least one countershaft, and including pairs of shiftable gears arranged on and cooperatively between said shafts, there are provided spring loaded clutches for effecting connection to one of said shafts of a selected one gear of a selected one of said pairs of said gears upon the achievement of substantial synchronization between such gear and such shaft. Blockers are provided for protecting the clutch teeth from excessive wear during such shifting and malfunctioning of said blockers is prevented in part by providing light frictional drag means between each of said blockers and the portion of said clutches rotatable with said shaft and in part by angling the leading surfaces of the blocker teeth an amount sufficient to effect an unblocking under one limited set of conditions but insufficient to prevent blocking under normal operating conditions.

Abstract: A shiftable change speed gear system, particularly a transmission, having resilient shifting mechanisms for simplifying the transmission structure and the shifting thereof. The transmission is preferably provided with multiple countershafts having countershaft gears thereon disposed in meshing engagement with main shaft gears encircling the transmission main shaft, said main shaft gears being supported on and solely by the countershaft gears. The main shaft gears are axially movable relative to the main shaft by conventional means for effecting shifting of the transmission.

Abstract: A shiftable change speed gear system, particularly a transmission, having resilient shifting mechanisms for simplifying the transmission structure and the shifting thereof. The transmission is preferably provided with multiple countershafts having countershaft gears thereon disposed in meshing engagement with main shaft gears encircling the transmission main shaft, said main shaft gears being supported on and solely by the countershaft gears. The main shaft gears are axially movable relative to the main shaft by conventional means for effecting shifting of the transmission.