Abstract:
An alignment tool for vehicular adaptive cruise control detection devices attaches with precision and repeatability to an adaptive cruise control sensor subassembly. Integral to this alignment tool is a low energy visible light laser that can be adjusted to point along the signal axis of the ACC sensor subassembly with stable and calibratable precision. The point at which a visible laser light beam strikes a reference surface can reveal the alignment of the ACC sensor subassembly with respect to the vehicle.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to automobile maintenance and repair calibration tools. More particularly, the present invention relates to a method and apparatus that aids in mechanically aligning and verifying the alignment of adaptive cruise control sensors.  
       BACKGROUND OF THE INVENTION  
       [0002]     Adaptive Cruise Control (ACC) is an evolution of cruise control devices that, in addition to measuring and regulating the forward speed of the vehicle on which the cruise control is mounted (own-car), can also measure the distance to and/or the relative speed of a vehicle ahead of the own-car. The ACC apparatus can permit normal cruise control operation within a range of acceptable conditions. When either the distance or the closing rate with respect to the vehicle ahead becomes unsatisfactory, the ACC can attempt to reduce own-car speed until an acceptable condition range is reestablished. Decreasing own-car speed may require, for example, reducing a throttle setting, canceling cruise control operation, and/or application of own-car brakes. Own-car speed may be allowed to resume if the condition ahead becomes acceptable before cruise control operation is canceled.  
         [0003]     ACC can use a sensor technology that transmits a beam, such as an ultrasonic acoustic, infrared optical, or radio frequency electromagnetic signal, in the forward direction with high precision. ACC can also use a directional receiver to detect such a signal. Whether a particular ACC design uses a directional transmitter, a directional receiver, or both, alignment precision can be important to avoiding interpreting traffic in adjacent lanes as being in the own-car lane. Either routine maintenance or repair may require readjustment or verification that the ACC sensor is properly aligned with the own-car longitudinal axis.  
         [0004]     Presently-existing test apparatus, such as optical frame alignment tools, are in common use, and can verify that the four corners of a vehicle have been properly realigned after body repairs, as well as to check wheel alignment with respect to the vehicle structure. It is possible to use an optical frame alignment tool to determine the fore-and-aft axis of a vehicle starting at some point on the front of the vehicle, but this is not the complete measurement required for ACC alignment, and converting such an axis determination to the required alignment test is cumbersome to perform and affords marginal accuracy.  
         [0005]     Accordingly, it would be desirable to provide a method and apparatus that aids in mechanically aligning and verifying the alignment of adaptive cruise control sensors.  
       SUMMARY OF THE INVENTION  
       [0006]     The adaptive cruise control sensor alignment tool described herein includes a fitting that attaches with precision and repeatability to an adaptive cruise control sensor subassembly. Mounted to this fitting is a low energy visible light laser that can be adjusted to point along the signal axis of the ACC sensor subassembly. The point at which the visible light laser beam strikes a reference surface indicates the alignment of the ACC sensor subassembly with respect to the vehicle.  
         [0007]     In another aspect, an adaptive cruise control sensor subsystem alignment tool comprises an illumination source, an illumination axis defined by the illumination source a plurality of gauge pins, each having a respective distal end, the distal ends arranged to define a plane, wherein the plane has a known orientation to the illumination axis, and a body to which the illumination source and the plurality of gauge pins are attached.  
         [0008]     In yet another aspect, an adaptive cruise control sensor subsystem alignment tool comprises means for illuminating a target, means for establishing an illumination axis defined by the illumination means, means for making simultaneous physical contact with a plurality of reference surfaces on the adaptive cruise control sensor subsystem, means for establishing a specified angular relationship between a plane defined by the means for making contact and the illumination axis defined by the illuminating means, wherein the angular relationship occurs at the center of emission of the adaptive cruise control sensor subsystem being aligned, and means for combining the means for illuminating and the means for making contact in a unitary assembly.  
         [0009]     In still another aspect, a method for aligning an adaptive cruise control sensor subsystem on a vehicle comprises the steps of providing an alignment tool, defining a target at which an axis of radiation of the adaptive cruise control sensor subsystem should point, establishing an illumination axis defined by a light beam on the alignment tool, contacting a plurality of reference surfaces on the adaptive cruise control sensor subsystem at specified orientations with respect to the axis of radiation of the adaptive cruise control sensor subsystem, establishing a specified angle between a plane defined by the plurality of reference surfaces on the adaptive cruise control sensor subsystem and a line defined by the axis of radiation of the adaptive cruise control sensor subsystem, and adjusting the orientation of the plurality of coplanar reference surfaces on the adaptive cruise control sensor subsystem until the illumination axis of the light beam on the alignment tool coincides with the target.  
         [0010]     There have thus been outlined, rather broadly, some of the features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.  
         [0011]     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.  
         [0012]     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a perspective view of a typical ACC detection device including the adjustable vehicle interface.  
         [0014]      FIG. 2  is a perspective view showing an exemplary alignment tool in place over the ACC detection device of  FIG. 1 .  
         [0015]      FIG. 3  is a top view of an alignment tool in accordance with the embodiment of the invention shown in  FIG. 2 .  
         [0016]      FIG. 4  is a front view of an alignment tool in accordance with the embodiment of the invention shown in  FIG. 2 .  
         [0017]      FIG. 5  is a perspective view of an alignment tool in accordance with the embodiment of the invention shown in  FIG. 2 .  
         [0018]      FIG. 6  is a front view of a second style of ACC detection device.  
         [0019]      FIG. 7  is a perspective view of the second style of ACC detection device shown in  FIG. 6 .  
         [0020]      FIG. 8  is a top view of a second calibration tool that can be attached to the second style of ACC detection device shown in  FIG. 6 .  
         [0021]      FIG. 9  is a front view of the second calibration tool shown in  FIG. 8 .  
         [0022]      FIG. 10  is a perspective view of the second calibration tool shown in  FIG. 8 .  
         [0023]      FIG. 11  is a perspective view of an articulated calibration tool.  
         [0024]      FIG. 12  is a process flow chart indicating steps in a method for using an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0025]     An adaptive cruise control (ACC) sensor alignment tool as described herein comprises a body with reference surfaces that contact corresponding surfaces on an ACC sensor, and an illumination source that can be calibrated to point along the beam of the ACC sensor to permit alignment of the ACC sensor. The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout.  
         [0026]      FIG. 1  shows a representative ACC assembly  10  for a vehicle, a part of which is an ACC sensor subassembly  12  that can detect the range and/or rate of approach of an external object, such as another vehicle, and generate an electronic signal corresponding to that range and/or rate. Within the ACC assembly  10 , the ACC sensor subassembly  12  can be weatherproof and substantially sealed, and can be mounted to a bracket  14  that can be installed at the front of the vehicle. The representative ACC sensor subassembly  12  and other embodiments referenced herein can be fitted with reference surfaces  16 ,  18 , and  20  that can exist in fixed relation to the radiation axis  22  of the sensor  12 . Thus, for example, in manufacturing the ACC sensor subassembly  12 , an ACC manufacturer can assemble a unitized sensor frame  24  that includes preferably flat and coplanar reference surfaces  16 ,  18 , and  20 , along with a transmitter, a receiver, or a transceiver fixed within the sensor frame  24  and is further covered or embedded inside a weatherproof shell or a coating of permanent sealing material  26 . The shell or sealing material  26  may be substantially transparent to the form of energy emitted and/or detected by the transmitter, receiver, or transceiver. During the building and sealing of the ACC sensor subassembly  12 , it is desirable that the plane defined by the reference surfaces  16 ,  18 , and  20  be aligned at a known orientation with respect to the radiation axis  22  of the transmitter, receiver, or transceiver.  
         [0027]     The ACC sensor subassembly  12  can be joined to the bracket  14  by adjustable fittings  28 ,  30 , and  32 . This allows alignment of the ACC sensor subassembly  12  to the vehicle to be accomplished by mechanical actuation of ACC adjustment screws  34  and  36 . It may be observed that the layout of the adjustable fittings  28 ,  30 , and  32  shown in  FIG. 1  allows the vertical and horizontal adjustments to be largely independent of each other. This can simplify alignment of ACC sensor subassembly  12 .  
         [0028]      FIG. 2  shows the above-described assembly  10  with an exemplary alignment tool  38  attached thereto. It may be seen that the alignment tool  38  has attached to its body  40  three gauge pins  42 ,  44 , and  46  that rest against the reference surfaces  16 ,  18 , and  20 , respectively, on the ACC sensor subassembly  12 . Since the body  40  of the alignment tool  38  is oriented substantially vertically in use, it is desirable to use spring tension to hold the gauge pins  42 ,  44 , and  46  in intimate contact with their respective reference surfaces  16 ,  18 , and  20 . This is realized in the exemplary alignment tool  38  by using three spring-loaded retention hooks  48 ,  50 , and  52  to carry the weight of the alignment tool  38  and to introduce sufficient friction to prevent the gauge pins  42 ,  44 , and  46  from shifting position after being attached to the ACC sensor  12  until the alignment tool  38  is removed. Like the reference surfaces  16 ,  18 , and  20  shown in  FIG. 1 , the tips  54  of the gauge pins  42 ,  44 , and  46  define a plane at a known orientation with respect to the radiation axis  22  of the ACC sensor subassembly  12 .  
         [0029]     The gauge pins  42 ,  44 , and  46  shown in  FIG. 2  may be of any suitable material or combination of materials, and are preferably made from hard, generally nonreactive materials such as ceramics and tool steels. Other materials, such as spring bronze, beryllium copper, some stainless steels, and other metal alloys, may be employed, particularly where the contact surface of the contact elements is no softer than and/or no less durable than the surface being contacted. Still other materials, including engineered plastics such as PEEK®, whether pure or mixed with finely divided solids such as talc or chopped fibers, can be employed, and may exhibit excellent wear properties along with low weight, good mechanical and thermal stability, and chemical nonreactivity. Coatings such as ceramics and finishes such as anodizing can be employed, and may also provide a hard and nonreactive finish over less durable but more manufacturable materials, and may allow, for example, the use of the same material for the body  40  and the gauge pins  42 ,  44 , and  46 . A similar benefit may be derived from the use of materials that can be annealed, machined, and then hardened.  
         [0030]     Each gauge pin  42 ,  44 , and  46  may be made from more than one piece, such as by co-molding a metallic threaded portion, a ceramic contact tip, and a plastic intermediate section into an integral component. Alternative gauge pin configurations may be preferable.  
         [0031]     Affixed to the body  40  of the alignment tool  38  is shown an illumination source  56 . This illumination source  56  can be, for example, a commercially available laser, which may comprise an envelope  72  in which are a laser diode with associated control and power circuitry, such as a power switch, a battery, a voltage regulator, and a voltage multiplier, as well as focusing and aiming apparatus and a provision for mounting the laser. Such a laser can provide a beam of light, such as visible light in the red portion of the visible spectrum, that is substantially collimated—that is, free of spreading. This light beam can project along an axis whose orientation with respect to gauge pins  42 ,  44 , and  46  is at least substantially the same as the orientation of the radiation axis  22  of the ACC sensor subassembly  12  with respect to the reference surfaces  16 ,  18 , and  20 . Thus, after the alignment tool  38  is attached to the ACC sensor subsystem  12  by placing the gauge pins  42 ,  44 , and  46  against the reference surfaces  16 ,  18 , and  20  and positioning the spring-loaded retention hooks  48 ,  50 , and  52  so as to hold the alignment tool  38  in place, the light beam from the illumination source  56  is at least substantially, and preferably to a high degree, parallel to and/or collinear with the radiation axis  22  of the ACC sensor subsystem  12 .  
         [0032]      FIGS. 3-5  show multiple views of the exemplary alignment tool  38 . The triangular shape of the body  40  is preferred to substantially minimize the amount of material as well as the complexity of fabrication required to build the body  40 , while preserving a desired degree of rigidity. As shown, the gauge pins  42 ,  44 , and  46  are preferably placed in an orthogonal relationship near the corners of the body  40 , with the spring-loaded retention hooks  48 ,  50 , and  52  situated for the retention task shown in  FIG. 2 , and with the illumination source  56  preferably placed essentially at the center of a circular relief  58 , shown in  FIG. 4 , in the body  40 . The relief  58  accommodates the shell or sealing material  26  of the ACC sensor subsystem  12 .  
         [0033]     The illumination source  56  and the gauge pins  42 ,  44 , and  46  are shown screwed into threaded holes  60 ,  62 ,  64 , and  66  in the body  40 . Material and workmanship tolerances are preferably selected to make this a suitably rigid and durable assembly with good initial alignment. Adjusting screws  68  and  70 , capable of repositioning the illumination source  56  within its protective outer shell  72 , are preferable to achieve fine alignment adjustment.  
         [0034]     As an example of a fine alignment requirement for an ACC sensor alignment tool  38 , a 40 mm circle may be marked on a vertical surface 7.5 meters from and at the same height as the illumination source  56 . If the ACC sensor subsystem  12  is designed so that the plane of the reference surfaces  16 ,  18 , and  20  is substantially perpendicular to the ACC sensor  12  emitting and/or detecting axis  22  and the direction of travel of the vehicle on which the ACC assembly  10  is mounted, and if the reference surfaces  16 ,  18 , and  20  are equidistant from the ACC sensor  12  emitting and/or detecting axis  22 , then fine alignment of the illumination source  56  is at least substantially realized when the tips  54  of the gauge pins  42 ,  44 , and  46  lie in a plane perpendicular to a line from the illumination source  56  to the center of the 40 mm circle and are equidistant from that line. Such an alignment may be made substantially permanent, for example, by using self-locking adjusting screws or by application of a material such as an adhesive sealant to conventional adjusting screws.  
         [0035]     The illumination source  56  may include further features such as an ability to allow removal of the shell  72  without disturbing alignment, which removal may permit replacement of one or more batteries (not shown). The illumination source  56  may also support a power switch (not shown) with an actuator slide  74 , preferably located as shown at the base of the illumination source  56  to permit the illumination source  56  to be switched on and off by moving the switch actuator slide  74  laterally.  
         [0036]     Each of the exemplary spring-loaded retention hooks  48 ,  50 , and  52  preferably has an extended center section  76 , a portion of which can slide through a pass hole  78  in the body  40 , an offset end  80  with a tip  82  that can make contact with an available location behind the reference surfaces  16 ,  18 , and  20 , a spring  84  that can provide the spring tension needed to apply force to the gauge pins  42 ,  44 , and  46 , and a handle  86  that can accept the force from the spring  84  pushing against the body  40  to withdraw the retention hook  48 ,  50 , or  52 . The retention hooks  48 ,  50 , and  52  can be constructed from a variety of materials, such as stainless steel, for example. The retention hooks  48 ,  50 ; and  52  can be made of more than one piece, such as by attaching the handle  86  by screwing, gluing, pinning, or the like. The offset end  80  can be bent into shape, machined, or made from a separate piece and attached by screwing, riveting, welding, or other methods. The handle  86  can be, for example, knurled, ribbed, smooth, or otherwise textured, and can incorporate a cross hole for ease in gripping. Although represented in  FIG. 3  as generally cylindrical, the handle  86  can be of any shape that allows it to be pressed and rotated and to provide a bearing surface for the spring  84 . The spring  84  can be a helical spring surrounding a portion of the retention hook  48 ,  50 , or  52  as shown in  FIG. 3 , or can have another form that permits rotation of the retention hook  48 ,  50 , or  52  and applies tension when needed.  
         [0037]      FIGS. 6 and 7  show a second style of ACC sensor subassembly  90  that is not physically compatible with the above alignment tool  38 . To permit alignment using the general approach described herein, it is preferable that the ACC sensor subassembly  90  or any other design of sensor to be aligned to a vehicle have an externally accessible reference plane  92  to which the transducer within the sensor subassembly  90  is permanently aligned. The reference surfaces  94 - 98  in  FIG. 6  define such a reference plane.  
         [0038]      FIGS. 8, 9 , and  10  show a second calibration tool  100 , one that is compatible with the sensor subassembly  90  of  FIG. 4 . An illumination source  102  can be affixed in the second style of body  104 , while three gauge pins  106 ,  108 , and  110  can, as in the previous configuration, allow precise contact with the reference surfaces  94 - 98  of  FIG. 4  that define the reference plane  92  of the sensor subassembly  90 . In this second embodiment, two spring-loaded retention hooks  100  and  102  are shown, which provide the requisite attachment force.  
         [0039]     Generic alignment tool designs are also possible, as shown in  FIG. 11 . For such a design  120 , the gauge pins  122  may need to be articulated while retaining the precision of rigid pins, while the spring-loaded retention hooks  124 , likewise, may require long reach, as shown in  FIG. 6 , or articulation similar to that of the gauge pins  122  themselves. These articulations may permit the illumination source  128  to be fixed with respect to the alignment tool body  126 , and may require the technician to make a reasonable effort to position the illumination source  128  above the radiation center of the ACC sensor subassembly being aligned. In a variation on this concept, the articulated alignment tool  120  can be used in conjunction with a setup station that can have setup processes for each type of ACC sensor subassembly to be aligned, allowing the gauge pins  122 , for example, to be locked for a particular sensor rather than movable.  
         [0040]     The method of application for many alignment tool designs may be similar, however. In many cases, as shown in  FIG. 12  in a procedural flow chart  130 , in which reference is made to reference numerals found in  FIGS. 1-3 , the device to be calibrated, such as an ACC sensor subassembly  12 , is to be aligned with the longitudinal axis of a vehicle. The adaptive cruise control assembly  10  can first be exposed sufficiently  132  to permit an alignment tool  38  to be affixed.  
         [0041]     Either before or after the above sequence, the vehicle under test can be set up  134 , which can comprise such steps as checking for proper tire pressure, loading the vehicle with the equivalent of driver and/or passenger weights, and positioning the vehicle on a level surface 7.5 meters from a vertical wall or equivalent reference plane. A reference line for the vehicle can be established using wheel centers, suspension reference points, body or frame points, or the like, indicating a precise direction of normal motion with respect to a specific point on the vehicle  136 . The intersection of the longitudinal axis so established and the reference plane may be used to define a starting reference point (at the front of the vehicle) and a finishing reference point (at the reference plane)  138 . Next, the lateral distance from the starting reference point to the center of the ACC sensor subassembly  12  can be transferred to the finishing reference point to establish a vertical target line  140 , and the height of the center of the ACC sensor subassembly  12  can be transferred to the vertical target line to establish the target point and can permit affixing a 40 mm-diameter target thereto, centered on the target point  142 .  
         [0042]     Next, in a preferred embodiment, the alignment tool  38  can have its spring-loaded retention hooks  48 ,  50 , and  52  swung out of the way  144 , after which the alignment tool  38  can be positioned so that its gauge pins  42 ,  44 , and  46  contact the reference surfaces  16 ,  18 , and  20  of the unit under test  146 . Preferably, the retention hooks  48 ,  50 , and  52  can be pushed against spring force and rotated until each hook tip is positioned behind its local reference point  16 ,  18 , or  20  or behind a convenient point on the reference surface as in  FIG. 6 . Each retention hook is then released to establish retention force  148 . Next, the illumination source  56  can be powered on  150 . The ACC sensor subassembly  12  can then be adjusted using ACC adjustment screws  34  and  36  until the illumination spot falls within the 40 mm circle  152 . The illumination source  56  may then be powered off, the alignment tool  38  removed, and the vehicle reassembled as necessary  154 .  
         [0043]     Alternative illumination source  56  designs may be identified that could be suitable for this application. Since the illumination source  56  can be expected to have a low duty cycle in many applications, there may a benefit in using a replaceable, disposable battery with long shelf life. An illumination source  56  powered from a rechargeable battery, the battery of the vehicle under test, or an electrical outlet, however, may be preferable where frequent or prolonged use is contemplated.  
         [0044]     A non-laser light source may be practical. Lasers are known for intrinsic low spreading and high power efficiency. Non-laser light sources such as light emitting diodes or halogen-filled filament bulbs, two of many examples of alternate light sources, may be able to fulfill the tight beam requirement through focusing, collimation, or other techniques. In applications where power limitations are less stringent, still other alternative light sources may be practical. Testing outdoors in full daylight or at low light levels inside a service center may dictate a specific light source performance level or capability for a source to emit at a multiplicity of brightness levels.  
         [0045]     Alternate attachment methods between the illumination source  56  and the body  40  are feasible. These might include, for example, a single female screw fitting at the base that would require a separate male screw to be applied from the opposite side of the body  40 . Another attachment method might be a friction fit sleeve separately mounted to the body  40  with or without a tapered nut to permit the illumination source  56  to be positively clamped. Another attachment method might use one or more threaded holes along a flat surface of the illumination source  56 , with an integral or added mating surface projecting out of the body  40  through which mounting screws could be driven into the threaded holes. These and other alternative mounting methods share the property of providing secure mounting that can be expected to remain fixed with respect to the body  40  after assembly.  
         [0046]     Adjustment of the alignment of the illumination source  56  may be realized in a variety of ways, of which the exemplary embodiment, which uses a pivoting bottom point (internal to the illumination source  56 ) and a pair of orthogonal adjusting screws  68  and  70 , is one that has been shown to be practical. Another adjustment method can use a non-adjustable illumination source  56  fixed to the body  40 , and can use, for example, threads with jam nuts on at least two of the three pins  42 ,  44 , and  46  so that screwing the pins  42 ,  44 , and  46  in and out and locking them in place, for example with the jam nuts, can adjust the direction of the beam of the illumination source  56  with respect to the plane defined by the tips  54  of the pins  42 ,  44 , and  46 .  
         [0047]     The tips  54  of the gauge pins  42 ,  44 , and  46  have been described herein as hemispherical in the exemplary embodiment. An alternative tip  54  design may be preferable, given that the reference surfaces  16 ,  18 , and  20  and  94 ,  96 , and  98  in the two ACC applications shown herein are all essentially flat and lie in common planes perpendicular to their respective ACC sensor axes. Other ACC sensor designs that provide reference surfaces and retention hook attachment locations different from those shown herein may require different interface styles without departing from the spirit of the invention.  
         [0048]     Attachment of the gauge pins  42 ,  44 , and  46  to the body  40  may use male screw threads integral to the gauge pins driven into female threaded holes in the body  40 . The female threaded holes in the body  40  may be reinforced with inserts, which inserts may be screwed, pressed, pinned, co-molded, or otherwise permanently installed. The gauge pins  42 ,  44 , and  46  themselves may similarly be screwed, pressed, co-molded, vibro-inserted, cryo-pressed, or installed by another suitable technology with or without inserts, or may be formed integrally with the body  40 , as by molding or machining, where the alignment tool calibration process does not forbid such a method of attachment. The gauge pins  42 ,  44 , and  46  may instead be attached to the body  40  using separate fastenings with unthreaded holes in the body  40 .  
         [0049]     As indicated above, the shape and the construction of the exemplary tool body  40  have been shown to achieve a combination of sturdiness, rigidity, and low weight. Materials and methods of manufacture as well as shape and construction are subject to review in light of total lifetime cost considerations, however. Thus, machining each tool body  40  from an aluminum slab might be preferable for production of a small number of alignment tools, while a process such as casting or injection molding the body from metal or an engineering plastic with or without reinforcement such as talc or fibers, and using co-molded or integral gauge pins, for example, might be preferable for quantities that justify more complex tooling. Other combinations of materials and manufacturing processes may be preferred when other criteria are applied.  
         [0050]     The spring-loaded retention hooks  48 ,  50 , and  52 , likewise, can have other implementations. The retention hooks  48 ,  50 , and  52  shown in the exemplary embodiment provide spring tension and are comparatively simple, while being unlikely to get caught on obstructions and interfere thereby with installation or removal of the alignment tool  38 . Alternative retention hook designs, such as the use of cam actuated clamping devices instead of or in addition to springs, may be preferable for these or other ACC sensor subassembly configurations. Hookless designs can be realized, using, for example, shop compressed air with a venturi-type vacuum generator to use one or more suction cups in place of retention hooks. A magnetic base, for another example, attached to the vehicle by an articulated arm, can likewise provide retention force. The retention hooks  48 ,  50 , and  52  can each be made of a single piece and captured by a separate clamp forming part of the pass hole  78 .  
         [0051]     The alignment tools and the methods of making, aligning, and using the tools that are disclosed herein are suitable for aligning adaptive cruise control sensor assemblies in a variety of hardware configurations. The tools and methods may also be suitable for other purposes, such as other alignment activities and activities other than alignment. Tools made and aligned according to the described methods can provide an arbitrarily accurate reference axis. A similar tool with a beam splitter or with multiple laser sources at various positions and orientations can provide multiple axes at any desired orientation with respect to a reference plane, which may be of use, for example, in setting up work in milling machines, assembling large machine parts, and other high-precision tasks.  
         [0052]     The many features and advantages of the invention are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and, accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the invention.