Automotive transmission shift system linear measurement device

A measurement device includes a base extending along a longitudinal axis, an input connector configured for attachment to a shifter assembly of a vehicle and a clamp configured for attachment to a linkage support bracket of the vehicle. The measurement device measures the linear displacement of a linkage interconnecting the shifter assembly and a transmission of the vehicle in response to movement of the shifter assembly between a first position and a second position. A scale is attached to the input connector and slideably supported by the clamp. A scale reader is attached to the base for measuring linear movement of the scale in response to movement of the shifter assembly between the first and second positions. Preferably, the scale and the scale reader comprise a digital measuring unit having a digital display for displaying the measured linear movement.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention generally relates to a measurement device for measuring a linear displacement of a linkage interconnecting a shifter assembly and a transmission of a vehicle. The linkage being linearly displaced in response to movement of the shifter assembly between a first position and a second position.

2. Description of the Prior Art

The linear displacement of the linkage interconnecting the shifter assembly and the transmission must be known so that the linkage may be properly designed for each vehicle, to ensure that the interaction between the shifter assembly and the transmission functions properly. The shifter assembly may be located on a steering column, or alternatively may be disposed within a center counsel of the vehicle. The linkage typically includes a combination of rods and/or push pull cables to transmit linear movement between the shifter mechanism and the transmission. The precise linear distance the shifter assembly travels when moving between a first position and a second position, i.e., between park and drive or between park and reverse, must be known and be coordinated with the transmission so that the movement of the shifter assembly corresponds to the accompanying movement of the transmission.

Previously, individual measurement devices have been constructed for each specific vehicle design. Accordingly, the prior art measurement devices were specific to each different vehicle. These prior art measurement devices typically coupled the shifter assembly to a series of rods, which were linked to one or more gages that would measure the movement of the connecting rods. If for example the shifter assembly was mounted to the steering column, the entire steering column/shifter assembly would need to be mounted to the prior art measurement devices. While these systems provided an estimate of the linear displacement of the linkage, the results were not exact because the prior art measurement devices did not actually simulate the actual movement of the linkage. This is because the prior art measurement device only moves linearly, whereas the actual linkage pivots along arcuate path in addition to moving linearly. Furthermore, these prior art measurement devices were large, heavy and cumbersome.

Accordingly, there remains a need for a more versatile measurement device that accurately simulates the movement of the linkage to measure the actual linear displacement of the linkage.

SUMMARY OF THE INVENTION AND ADVANTAGES

The subject invention provides a measurement device. The measurement device measures a linear displacement of a linkage. The linkage interconnects a shifter assembly and a transmission of a vehicle. The linkage is linearly displaced in response to movement of the shifter assembly between a first position and a second position. A linkage support bracket connects the linkage to the vehicle. The measurement device comprises a base. The base defines an elongated slot extending along a longitudinal axis. An input connector is configured for attachment to the shifter assembly, and includes a guided portion engaging the elongated slot. The guided portion engages the elongated slot for guided linear movement within the elongated slot relative to the base. The guided movement is in response to the movement of the shifter assembly between the first position and the second position. A clamp is pivotably coupled to the base. The clamp is configured for attachment to the linkage support bracket of the vehicle to fixedly securing the base to the linkage support bracket. A sensing unit is coupled to the base. The sensing unit senses the guided linear movement of the input connector relative to the base.

Accordingly, the measurement device of the subject invention attaches directly to the shifter assembly and the linkage support bracket of the vehicle in place, thereby simulating the actual movement of the linkage to provide a more accurate measurement and to provide a more versatile measurement device than known in the prior art. Because the measurement device of the subject invention attaches to the shifter assembly and the linkage support bracket directly, the measurement device may be utilized in place during prototype design, production, validation, and vehicle verification operations, thereby eliminating separate out of vehicle testing.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a measurement device is generally shown at20. Referring toFIGS. 1 and 2, the measurement device20measures a linear displacement of a linkage (not shown) interconnecting a shifter assembly22and a transmission (not shown) of a vehicle (not shown). The linkage is linearly displaced in response to movement of the shifter assembly22between a first position and a second position. It should be appreciated that the shifter assembly22includes several different positions corresponding to different positions of the transmission. The different positions of the shifter assembly22typically include a park position, a drive position, a neutral position and a reverse position. Accordingly, it should be appreciated that the first position and the second position may include any of the different positions of the shifter assembly22. It should also be appreciated that the different positions of the shifter assembly22may further include other positions specific to the transmission.

The shifter assembly22may be mounted to a steering column assembly24as is well known and shown inFIG. 1. Alternatively, the shifter assembly22may be mounted to a center counsel of the vehicle, i.e., the shifter assembly22may comprise a floor shifter as is also well known. The linkage typically includes a combination of rods and/or push-pull cables to transmit the movement of the shifter assembly22to the transmission.

A linkage support bracket26, best shown inFIG. 9, connects the linkage to the vehicle. The linkage support bracket26may be configured in any suitable manner to accommodate the different design constraints of the different vehicles. Accordingly, the linkage support bracket26may be differently configured in each different vehicle. However, it should be appreciated that the linkage support bracket26supports the linkage and provides a solid point of attachment between the linkage and the vehicle. If the shifter assembly22is mounted to the steering column assembly24, the linkage support bracket26may also be part of and attached to the steering column assembly24as shown. However, it should be appreciated that the linkage support bracket26may alternatively be attached to some other part of the vehicle, other than the steering column assembly24.

Referring toFIGS. 1 and 3through6, the measurement device20includes a base28. The base28defines an elongated slot30extending along a longitudinal axis32. The base28includes a top portion34and a bottom portion36cooperating together to define the slot. The top portion34and the bottom portion36are rigidly connected by a plurality of fasteners38extending through the top portion34and into threaded engagement with the bottom portion36. The top portion34and the bottom portion36cooperate together to define an interior cavity40therebetween. The internal cavity extends along the longitudinal axis32and is open to the elongated slot30. The purpose of the internal cavity is described in greater detail below.

An input connector42is coupled to the base28. The input connector42inputs the movement from the shifter assembly22to the measurement device20. The input connector42includes a guided portion44and an arm portion46. The guided portion44is in sliding engagement with the elongated slot30for guided linear movement within the elongated slot30. The guided portion44of the input connector42moves relative to the base28in response to the movement of the shifter assembly22between the first position and the second position. Accordingly, as the shifter assembly22is moved between the park position and the drive position, for example, the input connector42and thereby the guided portion44of the input connector42moves linearly relative to the base28.

As best shown inFIG. 6, the guided portion44of the input connector42includes a plate48. The plate48is disposed between the top portion34and the bottom portion36of the base28and moveable relative to the top portion34and the bottom portion36within the elongated slot30and the internal cavity. The internal cavity is sized to permit free movement of the plate48along the longitudinal axis32, yet prevent unwanted and undesirable lash between the plate48and the top portion34and the bottom portion36. The plate48assists in stabilizing the input connector42during linear movement to remove any lash between the base28and the input connector42.

Referring back toFIG. 2, the input connector42is configured for attachment to the shifter assembly22. The shifter assembly22includes a shifter attachment device50for connecting the shifter assembly22to the linkage. The shifter attachment device50may include a ball stud. However, it should be appreciated that the shifter attachment device50may include some other device20capable of pivotably attaching the linkage to the shifter assembly22.

As best shown inFIGS. 3 through 5, the input connector42includes a connector mechanism52. The connector mechanism52couples the input connector42to the shifter assembly22. More specifically, the connector mechanism52couples the input connector42to the shifter attachment device50. The attachment mechanism includes a seat54. The seat54engages the shifter attachment device50on the shifter assembly22.

The seat54may include a depression56for receiving the ball stud therein. As described above, the input connector42includes an arm portion46. The arm portion46is attached to and extends from the guide portion. The arm portion46extends from the guide portion to the shifter attachment device50. As shown, the arm portion46defines the seat54. However, it should be appreciated that the seat54may be disposed on the guide portion, and that the arm portion46merely permits for attachment to the shifter assembly22in spaced relationship relative to the guided portion44. As shown, the input connector42includes a first arm portion46A and a second arm portion46B. The second arm portion46B positions the seat54at a ninety degree (90°) angle relative to the first arm portion46A, to thereby permit attachment to other types of shifter attachment devices50. It should be appreciated that the shape and configuration of the shifter attachment device50and the seat54may encompass many different configurations, and that the scope of the invention should not be limited to the configuration and interaction between the shifter attachment device50and the seat54shown and described herein.

The connector mechanism52further includes a seat set screw58in threaded engagement with the input connector42. The seat set screw58secures the shifter attachment device50to the seat54. Accordingly, once the shifter attachment device50is firmly positioned in the seat54, the seat set screw58is advanced into engagement with the shifter attachment device50. The interaction of the seat set screw58and the shifter attachment device50prevents the shifter attachment device50from being withdrawn from the seat54, yet permits pivotable movement between the input connector42and the shifter attachment device50.

Referring toFIGS. 3, through5and7through9, a clamp60is fixedly coupled to the base28. The clamp60is configured for attachment to the linkage support bracket26of the vehicle, i.e., the linkage support bracket26and the base28are pivotable relative to the clamp60. Accordingly, the clamp60fixedly secures the base28to the linkage support bracket26.

The clamp60includes a generally C-shaped jaw having an insert62disposed on one portion of the jaw and a head64disposed opposite the insert62on the other portion of the jaw. As best shown inFIG. 9, the insert62is configured to mate with the linkage support bracket26in interlocking mechanical engagement. Preferably, the insert62includes a plurality of differently configured interchangeable inserts62, with each of the plurality of differently configured interchangeable inserts62configured to mate with a differently configured linkage support bracket26. As such, by changing the insert62within the clamp60, the measurement device20may be used with the different vehicles having differently configured linkage support brackets26.

The head64of the clamp60is moveable along a clamp axis66. The head64engages the linkage support bracket26opposite the insert62. As such, the linkage support bracket26is sandwiched between the insert62and the head64. The clamp60includes a biasing member68coupled to the head64for biasing the head64along the clamp axis66into engagement with the linkage support bracket26. Accordingly, the linkage support bracket26is retained between the insert62and the head64. The clamp60further includes a head set screw70for positionally securing the head64. Once the linkage support bracket26is positioned between the insert62and the head64, the biasing member68urges the head64into tight compressing engagement. The head set screw70is then advanced into engagement with the head64to secure the head64relative to the jaw of the clamp60to prevent the head64from moving.

A clamp connector72interconnects the clamp60and the base28. As shown, the clamp connector72includes a generally T-shaped configuration, in which an axial beam74extends along the longitudinal axis32. The clamp connector72includes a first attachment point76and a second attachment point78disposed along the axial beam74. The first attachment point76attaches the clamp60to the base28in a first position. The second attachment point78attaches the clamp60to the base28in a second position. The second position is axially spaced from the first position along the longitudinal axis32. It should be appreciated that the clamp connector72may be configured differently than shown or described herein to accommodate different vehicles. It should also be appreciated that the clamp60may alternatively be directly connected to the base28, thereby not utilizing the clamp connector72to interconnect the clamp60to the base28.

The clamp60includes a first pin80in pivotable engagement with the base28, and a second pin82in pivotable engagement with the clamp connector72. The second pin82is pivotably attached to one of the first attachment point76and the second attachment point78. The first pin80and the second pin82are axially aligned along a pivot axis84and spaced from each other along the pivot axis84to permit relative pivotable movement between the clamp60and the base28. In other words, the base28and the clamp connector72are free to pivot about the pivot axis84relative to the clamp60. The pivotal movement of the base28relative to the clamp60permits the measurement device20to accurately track or simulate the movement of the linkage. Accordingly, in response to movement of the shifter assembly22between the first position and the second position, the base28and thereby the input connector42pivot about the pivot axis84, while the input connector42also moves linearly along the longitudinal axis32.

The clamp connector72slideably supports a scale86, described in greater detail below. As shown, the clamp connector72defines a passage88with the scale86slideably disposed within the passage88. It should be appreciated that the scale86may be supported relative to the base28in some other manner not shown or described herein.

As best shown inFIGS. 3 through 5, the scale86is attached to and linearly moveable with the input connector42. More specifically, the scale86is attached to the guided portion44of the input connector42. Preferably, the scale86includes a linear encoder90for storing linear measurement data. The linear measurement data represents measurable incremental distances along the scale86. However, it should be appreciated that the scale86may alternatively include indicia printed thereon representing the measurable incremental distances along the scale86.

The measurement device20further includes a sensing unit92for sensing the guided linear movement of the input connector42relative to the base28. Preferably, the sensing unit92includes an electronic scale reader94. The electronic scale reader94is attached to the base28and coupled to the scale86. The scale reader94measures the linear movement of the scale86relative to the scale reader94. The scale reader94is capable of reading the linear measurement data stored within the linear encoder90of the scale86. However, it should be appreciated that the sensing unit92may include some manner of visual indicator permitting visual reading of the measured distance of the scale86relative to the scale reader94. For example, it should be appreciated that the sensing unit92may include a pointer, which is utilized to index or read measurement or distance indicia printed directly on the base28.

If the sensing unit92includes an electronic scale reader94, then the scale reader94may include an output96. The output96sends a signal, including data representing the measured linear movement, to a computer98. The computer98may store the data and utilize the data within a software program for analysis.

Preferably, a display100is coupled to the sensing unit92. The display100displays100the sensed, i.e., measured, linear movement of the input connector42. Specifically, the display100displays100the measured linear movement between the scale86and the scale reader94, which represents the displacement of the linkage under actual conditions. Preferably, the display100includes a digital display100. However, it should be appreciated that the display100may alternatively include a simple dial display100or the like. The display100may be integral with the sensing unit92. Alternatively, the display100may be coupled through cables to the sensing unit92and disposed remotely relative to the sensing unit92.

Preferably, the scale86, the scale reader94and the display100are combined into an electronic scale86unit. The scale86unit is preferably digital. One such suitable digital scale86unit suited for use in the subject invention is an ABSOLUTE Digimatic Scale86Unit™, manufactured by Mitutoyo Corp.

In operation, referring back toFIG. 1, the measurement device20is mounted to the shifter assembly22and the linkage support bracket26. As described above, the input connector42is attached to the shifter attachment device50and the clamp60is attached to the linkage support bracket26. Accordingly, the measurement devise sits in the place of the linkage, effectively simulating the linkage. In response to movement of the shifter bracket between the first position and the second position, the input connector42moves with the shifter assembly22relative to the base28and the clamp60. As the scale86is attached to the input connector42, the scale86moves with the input connector42along the longitudinal axis32. It should be appreciated that the plate48attached to the guided portion44of the input connector42moves within the internal cavity of the base28, and helps stabilize the movement of the input connector42and thereby the scale86from any undesirable lash, which is not associated with the actual movement of the linkage that the measurement devices20is simulating. As the scale86moves in response to the movement of the shifter assembly22, the scale reader94detects or measures the encoded data within the scale86to measure the movement of the scale86relative to the scale reader94. The movement of the scale86relative to the scale reader94is equal to the linear displacement that the linkage would encounter during operating conditions. The display100visually outputs96the measured linear displacement. The scale reader94may alternatively output96the measured linear displacement to a computer98for analysis.

The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. As is now apparent to those skilled in the art, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.