Sealed battery for coordinate measurement machine

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/796,973, entitled “SEALED BATTERY FOR COORDINATE MEASUREMENT MACHINE,” filed on May 1, 2006.

[0002] Also, this application hereby incorporates by reference the above-identified provisional application, in its entirety.

[0003] 1. Field of the Invention

[0004] The present application relates to measuring devices, and more particularly, articulated arm coordinate measurement machines for measuring the coordinates of three-dimensional objects.

[0005] 2. Description of the Related Art

[0006] Rectilinear measuring systems, also referred to as coordinate measuring machines (CMM's) and articulated arm measuring machines including portable coordinate measuring machines (PCMM's) have been described for generating geometry information from various objects and areas. In general, these instruments capture the structural characteristics of an object for use in electronic rendering and duplication. One example of a conventional apparatus used for coordinate data acquisition comprises a support and a moveable measuring arm made up of hinged segments to which a contact-sensitive probe or remote scanning device is attached.

[0007] Geometry information or three-dimensional coordinate data characterizing the shape, features, and size of the object may be acquired by tracing or scanning along the object's surface and contours. Probe or scanning device movement is typically tracked relative to a reference coordinate system resulting in a collection of data points and information that may be used to develop an accurate electronic rendering of the object. In conventional implementations, the acquired geometry information is processed by a computer capable of making use of the information to model the surface contours and dimensions of the object.

[0008] In one embodiment, a coordinate measurement apparatus comprises a base configured to at least contain one or more removable batteries, a cover member configured to be secured to the base and one or more seal members situated between the base and the cover member. In one arrangement, the cover member of the coordinate measurement apparatus substantially encloses the removable battery. In another embodiment, the coordinate measurement apparatus further comprises one or more securement members which are configured to secure the cover to the base. In yet another embodiment, the securement member is a bolt.

[0009] In some embodiments, the seal member situated between the base and the cover is a gasket, an o-ring, a silicone membrane, a seal, a sealant and/or the like. In another arrangement, the cover is configured to prevent moisture from contacting the battery. In one embodiment, the cover is configured to prevent dust from contacting the battery. In another embodiment, the seal member is attached to the cover. In yet another embodiment, the cover is configured to satisfy at least one industry accepted standard for the enclosure of electrical components. In one embodiment, the cover is configured to meet the Ingress Protection 65 (IP65) standard.

[0017] FIG. 1 illustrates one embodiment coordinate measuring machine (CMM) 10. In the illustrated embodiment, the CMM 10 comprises a base 20, a plurality of rigid transfer members 24, 26, 28, a coordinate acquisition member 30 and a plurality of articulation members 40, 42, 44, 46, 48, 50 connecting the rigid transfer members 24, 26, 28 to one another. Each articulation member is configured to impart one or more rotational and/or angular degrees of freedom. Through the various articulation members 40, 42, 44, 46, 48, 50, the CMM 10 can be aligned in various spatial orientations thereby allowing fine positioning of the coordinate acquisition member 110 in three dimensional space.

[0018] The position of the rigid transfer members 24, 26, 28 and the coordinate acquisition member 30 may be adjusted using manual, robotic, semi-robotic and/or any other adjustment method. In one embodiment, the CMM 10, through the various articulation members, is provided with seven rotary axes of movement. It will be appreciated, however, that there is no strict limitation to the number of axes of movement that may be used, and fewer or additional axes of movement may be incorporated into the CMM design.

[0019] In various embodiments, the coordinate acquisition member 30 comprises a contact sensitive member or probe 32 configured to engage the surfaces of a selected object and generate coordinate data on the basis of probe contact. Alternatively, the coordinate acquisition member 30 may comprise a remote scanning and detection component that does not necessarily require direct contact with the selected object to acquire geometry data. In one embodiment, a laser coordinate detection device (e.g., laser camera) may be used to obtain geometry data without direct object contact. It will be appreciated that various coordinate acquisition member configurations including: a contact-sensitive probe, a remote-scanning probe, a laser-scanning probe, a probe that uses a strain gauge for contact detection, a probe that uses a pressure sensor for contact detection, a probe that used an infrared beam for positioning, and a probe configured to be electrostatically-responsive may be used for the purposes of coordinate acquisition.

[0020] In other embodiments, one or more of the rigid transfer members 24, 26, 28 comprise a composite structure that includes an inner portion and an outer exoskeletal portion. In such an arrangement, the inner portion of the rigid transfer members 24, 26, 28 are interconnected to one another through articulation members that provide the ability to position the coordinate acquisition member 30 in a variety of different orientations in three dimensional space. The outer portions surrounding the various inner portions of the rigid transfer members 24, 26, 28 form an environmental barrier that at least partially encloses segments of the inner portions. In one aspect, the inner portions are configured to “float” inside the corresponding outer portions.

[0021] As is known in the art, the position of the probe 32 in space at a given instant can be calculated by knowing the length of each member and the specific position of each of the articulation members 40, 42, 44, 46, 48, 50. Each of the articulation members 40, 42, 44, 46, 48, 50 can be broken down into a singular rotational degree of motion, each of which is measured using a dedicated rotational transducer. Each transducer outputs an signal (e.g., an electrical signal), which varies according to the movement of the 40, 42, 44, 46, 48, 50 in its degree of motion. The signal can be carried through wires or otherwise transmitted to a the base 20. From there, the signal can be processed and/or transferred to a computer for determining the position of the probe 32 in space.

[0022] In one embodiment, the transducer can comprise an optical encoder. In general, each encoder measures the rotational position of its axle by coupling is movement to a pair of internal wheels having successive transparent and opaque bands. In such embodiments, light can be shined through the wheels onto optical sensors which feed a pair of electrical outputs. As the axle sweeps through an arc, the output of the analog encoder can be substantially two sinusoidal signals which are 90 degrees out of phase. Coarse positioning can occur through monitoring the change in polarity of the two signals. Fine positioning can be determined by measuring the actual value of the two signals at the instant in question. In certain embodiments, maximum accuracy can be obtained by measuring the output precisely before it is corrupted by electronic noise. Additional details and embodiments of the illustrated embodiment of the CMM 10 can be found in U.S. Pat. No. 5,829,148, the entirety of which is hereby incorporated by reference herein.

[0023] In one embodiment, the base 20 of the CMM 10 may be situated on a support surface, such as a table, floor, wall or any other stable surface. In another embodiment, as shown in FIG. 2, the base 20A may be positioned on a mobile unit 14, allowing the CMM 10A to be conveniently moved from one location to another. In such arrangements, the base 20A may be secured to the mobile unit 14 in a fixed manner (e.g. bolted, fastened or otherwise attached at one or more locations). Further, the mobile unit 14 may be configured with retractable or drop-down wheels 16 that facilitate in moving the CMM 10A. When properly positioned at the desired location, the wheels 16 may be retracted and rigid support legs (not shown) may be used to secure the CMM 10A in a fixed and stable position in preparation for the acquisition of coordinate data. Additional details of this embodiment of the CMM 10 can be found in U.S. Patent Publication 2005-015012, the entirety of which is hereby incorporated by reference herein.

[0024] FIGS. 3-6 are front perspective, front, side and cross-sectional views of an embodiment of a base portion 20B, which can be used in combination with the CMM 10, 10A embodiments described above or other CMM devices. In the illustrated embodiment, the base portion 20C includes a battery 60 (see FIG. 6) that is positioned at least partially within a receptacle 61 in the base 20B to supply a portion or all of the necessary electrical output to operate the device. The use of batteries 60 is particularly useful for portable CMMs that may not have easy or convenient access to a standard AC power supply during use.

[0025] In the illustrated embodiment, the battery 60 can be removed from the base 20B for replacement, external recharging or any other purpose. For cost-savings and other practical considerations, the battery 60 is preferably rechargeable. Types of rechargeable batteries can include nickel cadmium (Ni-Cad), nickel metal hydride (Ni-MH), lithium batteries or the like. Alternatively, those of skill in the art recognize that single use batteries may also be used. It will be appreciated that a single CMM may include two or more batteries 60. In addition, in modified embodiments, the one or more batteries 60 may be situated in any other suitable portion of the CMM besides the base 20B.

[0026] In an embodiments, rechargeable batteries used in a CMM device may be advantageously housed within a battery adapter that also serves as a battery charger. Thus, in one embodiment, the battery 60 is recharged while secured within the CMM 20C by simply attaching the CMM 20C to an external power supply (e.g., AC power source). In another embodiment, the CMM 20B can be configured so that the battery 60 is recharged by an external charger.

[0027] In the illustrated embodiment, the battery 60 can be configured to be positioned within receptacle 61 in the base 20C or another other part of the CMM 10C. With particular reference to FIG. 6, the battery 60 can be positioned in the receptacle 61 near the bottom of the base 20B on a front portion of the CMM 10C. To ensure that the battery 60 has been properly positioned within the slot or adapter, a snap fit or another type of positive engagement or locking mechanism can be optionally provided.

[0028] As shown in FIG. 6, in the illustrated embodiment, the CMM 10C includes a cover 62 configured to enclose the battery 60 within the base 20B. The cover 62 is preferably sized and shaped to snugly fit over the battery 60 and the adjacent surfaces of the CMM 10B so as to completely conceal the battery within the base 20B. In one embodiment, one or more sealing members 66 are included between the cover 62 and the outer surface of the base 20B or other surface of the CMM 10B. This is particularly important for CMMs that are used in environments where contaminants and other outside elements (e.g., dust, water, etc.) are present. In such situations, it is important to keep contaminants away from electrical and other sensitive internal components of the CMM 10B. Therefore, the battery 60, the electrical contacts and any other internal components are protected from corrosion and/or other similar damage resulting from exposure to the elements. Further, with or without the sealing members 66, the cover 62 can help to prevent the accidental disconnection of the battery 60 from the corresponding electrical contacts. In addition, the cover 62 can protect the battery 60 from damage resulting from the accidental contact with other objects during operation of the CMM 10B.

[0029] The one or more sealing members 66 can include o-rings, gaskets, silicone membranes, seals, sealants and/or any other material. Typically, the sealing members 66 are made of a compressible material (e.g., rubber, Viton, silicone, etc.) to further enhance the sealing effect between the cover 62 and the adjacent surfaces of the CMM 10B. The battery cover 62 may be constructed of one or more rigid or semi-rigid materials, including, but not limited to, aluminum, steel, stainless steel, iron, fiberglass, plastic, polycarbonate, acrylonitrile butadiene styrene (ABS), polystyrene or the like. In some arrangements, two or more different materials may be used to construct a single cover 62. Further, the cover 62 can include a solid, clear, translucent, transparent and/or other type of construction.

[0030] As illustrated in FIGS. 3-6, in the illustrated embodiment, the cover 62 can be connected to the base 20C using two fasteners 64. In the preferred embodiment, the fasteners 64 comprise bolts 64 that can be removed with a tool (e.g., an Allen Wrench or Hex Key). In this manner, the cover 62 is not easily removed or dislodged. Those of skill in art will appreciate that fewer or more than two fasteners 64 can be used and that the position of the fasteners 62 can be modified. For example, in FIG. 6, a fastener is shown being position on an upper, central portion of the cover 62. In certain embodiments, the use of the fasteners 64 in combination with the sealing member 66 can eliminate or reduce the amount of dust, water, other fluids and any other contaminants that contact the battery 60 and the other internal components of the CMM 10C. Thus, in one embodiment, the battery 60 is completely concealed within the base 20C.

[0031] In some embodiments, the cover is advantageously designed to meet and/or exceed one or more industry-recognized ratings for the protection of electrical components (e.g., IP65). Such industrial standards, as administered by the International Electrotechnical Commission (for Ingress Protection (IP) standards), National Electrical Manufacturers Association (NEMA) and others, ensure that a cover 62 or other electrical housing is adequately designed for a particular environment. For example, there are different Ingress Protection (IP) ratings for protection against exposure to moisture (e.g., dripping water, spraying water, immersion, submersion, etc.). In one embodiment, the cover 62 and other components of the battery protection system are capable of achieving a IP62 rating or better. The various characteristics (e.g., size, material, thickness, shape, etc.) of the cover 62 and the sealing members 66 can be modified to satisfy the desired level of protection.

[0032] The various devices, methods, procedures, and techniques described above provide a number of ways to carry out the invention. Of course, it is to be understood that not necessarily all objectives or advantages described may be achieved in accordance with any particular embodiment described herein. Also, although the invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. Accordingly, the invention is not intended to be limited by the specific disclosures of preferred embodiments herein.