Transmission mounted solenoid interlock device

An electrically controlled transmission shift interlock device. The device provides interlock capability by locking the pivotable shift actuating lever which is operatively associated with the transmission. A transmission mounted solenoid is provided having a moving armature coupled to a locking member which, when energized, positions the locking member into interlocking engagement within an engaging notch provided in the shift actuating lever. The device includes means for proper alignment of the interlocking components during installation of the interlock device onto the transmission. One alternate embodiment further provides means for having interlocking capabilities at more than one gear shift lever position. Another embodiment causes the transmission actuating lever to lock when the solenoid is de-energized and is movable upon energization.

BACKGROUND AND SUMMARY OF THE INVENTION 
This invention relates to a lever locking device and particularly to a 
transmission shift lever locking device for motor vehicle applications. 
Automobile manufacturers are evaluating devices which lock automatic 
transmission shift levers in certain operating modes. This invention is 
directed toward a design for such a shift lever interlock device. The 
present invention employs an electrically energized solenoid coupled to a 
pivotable locking member which is mounted on the outer transmission 
housing in close proximity to a transmission mounted shift actuating 
lever. The transmission mounted shift actuating lever is coupled to an 
operator actuated gear shift lever through remote actuation means such as 
a cable, rigid linkage or any other known method. The solenoid locking 
member engages a slotted engaging notch on the shift actuating lever which 
prevents the gear selection from being changed, for example, out of the 
"park" position. The solenoid locking member can be activated to disengage 
the engaging notch, thereby permitting free movement of the shift 
actuating lever. The system can be designed to lock the shift actuating 
lever when the solenoid is energized or de-energized, depending on the 
requirements of the vehicle manufacturer. 
In accordance with a preferred embodiment of the present invention, means 
for properly locating the solenoid interlock device during installation 
are provided to allow orientation and alignment of the locking member. The 
locking member must be aligned to properly engage the engaging notch of 
the shift actuating lever when the vehicle transmission is set in the park 
(or other) position. 
Additional benefits and advantages of the present invention will become 
apparent to those skilled in the art to which this invention relates from 
the subsequent description of the preferred embodiments and the appended 
claims, taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 illustrates a motor vehicle automatic transmission shifter assembly 
10 in operative association with a transmission mounted solenoid interlock 
device 12 in accordance with this invention. Shifter assembly 10 includes 
mounting plate 14 for mounting on the floor pan of a motor vehicle. Gear 
shift lever 16 is pivotable through a limited angular range with various 
angular positions corresponding to a particular transmission gear 
selection. Gear shift lever 16 is mounted to clevis 18 which is pinned for 
rotation with respect to plate 14 by clevis pin 20. 
Automatic transmission shifter assembly 10 and solenoid interlock device 12 
are shown to be operatively associated through actuation cable assembly 22 
which couples shifter assembly 10 to a pivotable transmission mounted 
shift actuating lever 30. Transmission shift cable assembly 22 includes an 
outer sheath 24 with an end fitting 25 which is supported by plate 14 at 
restraining notch 26. Shift cable rod 28 attached to an end of cable core 
29 is affixed to clevis 18 via pin 27 such that arcuate motion of gear 
shift lever 16 causes the rod to be moved in and out of outer sheath 24. 
Shifter assembly 10 would further include (not shown) some means for 
indicating to the operator the transmission selection position at which 
gear shift lever 16 is set. Such indicia can be provided, for example, in 
the form of a labeled elongated slot through which gear shift lever 16 
passes, or through remotely actuated shift indicator devices which are 
well known according to the prior art. The opposite end of cable assembly 
22 is coupled to the vehicle's automatic transmission. At the 
transmission, a bracket (not shown) is provided which restrains outer 
sheath 24, whereas cable inner core 29 is coupled to pivotable 
transmission mounted shift actuating lever 30. Axial motion of cable inner 
core 29 within outer sheath 24 translates into pivotable motion of shift 
actuating lever 30 through a limited angular range directly corresponding 
to a particular transmission gear selection via gear shift lever 16. It 
would alternatively be possible to provide a transmission with a linearly 
actuated shift lever or rod (not shown). Movement of transmission mounted 
shift actuating lever 30 is communicated to the transmission via a shaft 
31, extending through the transmission and coupled at its outermost end to 
shift actuating lever 30. Rotation of shaft 21 communicates the gear 
selected via gear shift lever 16 to the transmission. 
It is contemplated that transmission mounted solenoid interlock device 12 
is adaptable for application without regard to the type of remote 
actuation means utilized to move the shift actuating lever. Actuation 
means such as rod-type linkages, rotary cables, etc. are examples of 
methods other than linear actuation cables which could be readily 
utilized. 
In accordance with a principal feature of this invention, a solenoid 
interlock device 12 is provided which activates a pivotable locking member 
36 which provides the interlock function such that shift actuating lever 
30 is restrained at a particular position from motion by engagement of the 
locking member 36 with a lock engaging slot 38 formed in shift actuating 
lever 30, until the device is released. Solenoid interlock device 12 is 
secured to a substantially U-shaped mounting bracket 32 which is mounted 
to outer transmission housing 34. 
With particular reference to FIGS. 2, 3 and 4, the components making up 
solenoid interlock device 12 and the locked and unlocked relative angular 
positioning of the locking member 36 and shift actuating lever 30 are 
shown. Solenoid interlock device 12 is structurally designed to protect 
the working components therein from the severe environment beneath the 
vehicle's floor pan where it is subject to corrosives, severe vibration 
and thermal stresses. Specifically, housing 40, cover 42, bracket 32 and 
locking member 36 are coated with an anti-corrosion material and assembled 
so as to reduce the effects of the severe environment encountered. Pole 
piece 44 is fixedly mounted within housing 40. Pole piece 44 is staked to 
a radially extending flange 48 which acts as a flux collector at one of 
its axial ends and forms a convex frusto-conical surface 50 at its 
opposite end. Axially extending passage 52 is provided within pole piece 
44 at its end adjacent surface 50. 
Armature 54 is movable in an axial direction through a limited range of 
motion within housing 40 and defines a concave frusto-conical surface 56 
which corresponds in shape to that of pole piece surface 50. Additionally, 
axial passage 57 is formed within armature 54 at its end adjacent surface 
56 such that passages 52 and 57 are axially aligned. Noise damper 64 is 
disposed within axial passage 57. Armature 54 further defines an annular 
extension 58 having a necked portion 60 provided for coupling locking 
member 36 to armature 54. Coil bobbin 66 encirlces pole piece 44 and 
armature 54, and forms a pair of axially separated flanges 68 and 70 which 
confine and support bobbin 66. Flux collector rings 74 and 76 are 
positioned adjacent bobbin 66. Return spring 78 is disposed within axial 
passages 52 and 57, and biases armature 54 away from pole piece 44. 
Shift actuating lever 30 engaging slot 38 is positioned to be aligned with 
engaging portion 35 of interlocking member 36 when the transmission is set 
in the park position. Engaging portion 35 of locking member 36 enters slot 
38 to provide the interlockig function as will be described hereinafter. 
FIG. 3 illustrates the orientation and cooperation of elements of solenoid 
interlock device 12 when winding 72 is energized which causes the 
transmission to be locked in the park position. As shown, armature 54 is 
drawn toward pole piece 44 by the induced magnetic field from winding 72. 
The tapered working air gap provided by the frusto-conical surfaces 50 and 
56 provides a desired level of attractive force of armature 54 over a 
fairly long stroke distance of the armature. However, it is contemplated 
that other working air gap configurations such as planar air gaps could be 
utilized. In the position shown in FIG. 3, the energized solenoid 
interlock device 12 acts to pivot locking member 36 against wall surfaces 
80 and 82 of access slots 84 and 86, respectively, provided through 
mounting bracket 32. Engaging portion 35 of locking member 36 is thereby 
positioned within engaging slot 38 such that shift actuating lever 30 is 
interlockingly restrained from moving from the park gear position until 
the solenoid is de-energized. Solenoid interlock device 12 is designed 
such that forces imposed by shift actuating lever 30 onto the device do 
not directly load armature 54. This design provides compactness and 
structural efficiency for the overall structure. 
FIG. 4 illustrates the orientation and cooperation of elements of solenoid 
interlock device 12 when winding 72 is de-energized so as to unlock the 
transmission from the park position. Upon interruption of electrical 
current to winding 72 caused, for example, by the operator depressing the 
vehicle's brake pedal, the magnetic attraction between pole piece 44 and 
armature 54 is relieved and the biasing force of spring 78 is allowed to 
move armature 54 away from pole piece 44. Once armature 54 is fully 
extended away from pole piece 44, pivotable locking member 36 is outwardly 
positioned so as to seat against the rearward surface 81 and 83 of 
respective access slots 84 and 86. In this position, locking member 36 is 
no longer interlockingly engaging the engaging slot 38 of shift actuating 
lever 30, thereby allowing pivotable motion of shift actuating lever 30 
via actuation of cable assembly 22 through the desired arcuate motion of 
gear shift lever 16. 
With particular reference to FIG. 5 and 6, the locked and unlocked 
positions of the present invention are respectively presented. For proper 
installation positioning of the interlocking components installation, 
alignment means are provided. According to a preferred embodiment of this 
invention, installation alignment is provided by a pinning extension 
surface 90 on mounting bracket 32 having a bore 92 extending therethrough. 
Pivotable shift actuating lever 30 further defines a two legged member 
wherein a first leg 94, coupled to shift cable core 29, has a pinning bore 
96 alignable with mounting bracket pinning hole 90 upon interlocking 
orientation of engagement slot 38 and engaging section 35 of locking 
member 36. The installation alignment means effectively locate the park 
position for installation of the solenoid interlock device 12 to the 
transmission housing 34. Alternatively, lever 30 could be formed as a 
simple intergral shape without distinct legs as described above. 
Mounting bracket hole 98 is slotted such that tolerance variations in the 
transmission housing 34 and the mounting bracket 32 can be readily 
accommodated. Subsequent to securing solenoid interlock device 12 in 
proper alignment to transmission housing 34, adjustment of the remote 
actuation means (i.e., cable assembly 22) accommodates tolerance 
variations in the vehicle so as to synchronize the positions of gear shift 
lever 16 and transmission shift actuation lever 30. The second leg 100 of 
shift actuating lever 30 includes the engaging slot 38. Upon release of 
locking member 36 from engaging slot 38, shift actuating lever 30 is 
capable of a range of pivotable motion corresponding to arcuate motion of 
gear shift lever 16 as selected by the vehicle operator. 
The solenoid interlock device 12 according to the first embodiment of this 
invention is provided with a failure mode adapted to permit shifting of a 
transmission upon failure of the vehicle's electrical system. Solenoid 
interlock device 12 is actuated upon energization of the windings 72. 
Energization of windings 72 is provided via an electrical current supplied 
by energization of the automobile ignition system upon starting, thereby 
preventing interlocked actuation of the solenoid interlock device 12 
whenever the vehicle is not running or upon failure of the electrical 
circuit controlling the device. 
It is contemplated that pivotable actuation lever 30 could further 
incorporate an additional engaging slot 39 so as to enable solenoid 
interlock device 12 to lock at two positions, thus enabling the 
manufacturer to provide interlocking capability operable at either the 
neutral or park positions. 
FIG. 7 illustrates an alternate embodiment of this invention which is 
generally designated by reference number 112. This embodiment is 
substantially identical to that previously described with the exception 
that is is configured to lock transmission shift actuation lever 130 upon 
de-energization of solenoid winding 72. For this embodiment, shift 
actuating lever 130 is extended such that it engages modified locking 
member engaging portion 135 when it is moved from the position shown to 
its rightmost position. In the engaged position, engaging portion 135 
meshes with engaging slot 138 as described previously. In all other 
respects, solenoid interlock device 112 is identical to that described 
previously and identical components are designated by like reference 
numbers. 
While the above description constitutes the preferred embodiment of the 
present invention, it will be appreciated that the invention is acceptable 
to modification, variation and change without departing from the proper 
scope and fair meaning of the accompanying claims.