Abstract:
A portable device for measuring deflection of a surface, comprising an elongate frame having a first end and a second end and a first datum surface, a first removable reference assembly adjacent the first end, a second removable reference adjacent the second end, a deflection gauge attached to the elongate frame between the first removable reference assembly and the second removable reference assembly, and wherein the deflection gauge engages and measures a deflection of the surface relative to the first removable reference assembly and the second removable reference assembly.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to measurement of surface deflection of vertical surfaces and, more specifically, to measurement of deflection of a window or door frame. 
     BACKGROUND OF THE INVENTION 
     In many fields, it is often necessary to measure the amount that a vertical surface or frame has been bent or deflected. Such a situation arises in disaster recovery in response to wind damage or other accidents or natural disasters. Measurement of damage is necessitated by retrofit procedures which may be required as well as insurance recovery and insurance adjustment. 
     One of the major problems in measuring the deflection over longs spans, such as in large window frames, is the lack of convenient, portable tools to measure the deflection. A typical tool available is a masons bubble level as well known in the art. A bubble level determines whether a surface is level and plumb (truly vertical or horizontal), but does not quantify the deflection of the surface. 
     U.S. Pat. No. 5,388,338 to Majors discloses an expandable screed level. The level has an open rectangular cross section and uses liquid bubble levels to determine slope. The device is expandable by adding additional sections at either end. The additional sections attach by means of a smaller rectangular cross section that fits inside the main body. The additional sections are retained in position by use of a latching mechanism. However, Majors makes no provision for measuring the displacement of a warp in a frame. 
     U.S. Pat. No. 5,433,011 to Scarborough et al discloses an expandable level. The level is expandable as a straight level, a square, a T-square and other shapes. Additional sections are added to the main body through a tongue and groove arrangement. A pressure screw is tightened to lock the pieces together. The device measures slope through use of liquid bubble levels. Each expansion piece contains at least one level. However, no provision for measuring deflection of a frame is provided. 
     U.S. Pat. No. 4,939,848 to Armstrong discloses an improved alignment gauge to check misalignment of the body of a vehicle. The device determines the distance between various physical points on the vehicle in order to aid in proper alignment. The device consists of a needle indicator attached at one end of a beam. The beam supports a horizontal and vertical liquid bubble level. The invention produces a precise result, but does not address the problems of ease of transport and use. It does not measure deflection along a long linear surface, but rather at specific points. 
     U.S. Pat. No. 7,497,022 to Aarhus discusses an extendable level. Telescopic extensions are contained within a main body of the level extension. Each terminates in an end piece. The extensions are supported by cross members. Each cross member and the main body includes a liquid bubble level. The invention facilitates viewing but does not measure depth or deflection. 
     US 2003/0033722 to Lanham discloses a telescopic leveling instrument having a body and telescopic extensions. The telescopic extensions are oriented horizontally or vertically. The extensions are marked to allow distance measurement. The main body includes a bubble level. The device measures distance but does not measure depth or deflection perpendicular to the surface. 
     U.S. Pat. No. 5,303,480 to Chek discloses a device to measure the amount of deviation of a patient&#39;s facial symmetry from a “standardized norm.” The device consists of a rod shaped base and a portable probe that is movable horizontally. The base is placed against a patient&#39;s sternum and maintained at horizontal by monitoring a liquid bubble level. The probe is then set against various facial features and the horizontal and radial distance from the sternum to the probe is measured. However, the device does not provide a means to measure depth between two points on a particular surface or over long distances. Further, the device is incapable of measuring multiple points of deflection at the same time. 
     U.S. Pat. No. 4,691,443 to Hamilton et al discloses a vehicle alignment system. The system includes fittings connected to beams that allow access to a vehicle, while maintaining the measurement surfaces in horizontal or vertical orientation. Lasers are used to project X, Y and Z coordinates. The device is not portable. The device also does not provide a means to measure deflection of a freestanding vertical beam. 
     U.S. Pat. No. 5,388,338 to Majors describes an extendable screed level. The level includes extensions that mount to a main body. The extensions enter a channel in the main body and are locked into position with releasable catches. The extensions produce an increase in length that allows the level to span retaining walls of various widths, forming a barrier to hold wet cement. The level of Majors includes a bubble level to ensure the surface of the wet cement is horizontal. However, Majors does not provide for determining a measurement of deflection of vertical surfaces. 
     Additionally, prior art does not address the problem in measuring deflection in a vertical beam by a single individual. Often the window frames are quite large, requiring spanning eight or more feet in order to determine the deflection. It is difficult and unwieldy for a single individual to hold prior art levels against such a window frame and measure the deflection accurately or consistently. 
     Therefore, a need exists for an economical device for measuring deflection of large surfaces, including window frames, which can be operated single-handedly. A need also exists for a deflection measurement device which is portable and may be used in the field. Still further, a need exists for a simple uncomplicated device to measure deflection of a vertical beam at or around its center point. A further need exists for a device which is expandable to fit both large and small spans, without the need for additional tooling or calibration. A still further need exists for a device to measure many points of deflection over a surface simultaneously between a pair of reference points. 
     SUMMARY OF THE INVENTION 
     The preferred embodiment includes a device and method for determining the deflection of a long freestanding vertical beam. A common use would be measuring the deflection of frames of large windows or doors. 
     One embodiment includes of an elongate frame having an adjustable reference assembly located at each end. A gauge is located centrally in the elongate frame and positioned to measure a deflection from two calibrated reference assemblies. A centrally located handle is provided for ease of use, allowing a single individual to hold the device and manipulate the measurement gauge. 
     Expansion sleeves are provided which can be attached precisely and rigidly to each end of the frame in order to expand the span of the device. The reference assemblies are then removed and placed at the end of the additional lengths. The reference assemblies are designed and constructed so that re-calibration is not required. Alternatively, the additional lengths incorporate additional pre-calibrated reference assemblies. 
     In another embodiment, the deflection at several locations along a given frame may be measured by repositioning the support frame, or, in another preferred embodiment, by several gauges simultaneously. 
     In use, the device is first calibrated. Then, the reference assemblies are positioned against a span of window frame or other surface by manipulation of the elongate frame. The gauge in the elongate frame provides a reading of deflection. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a side view of a preferred embodiment. 
         FIG. 2  is a cross sectional side view of a preferred embodiment. 
         FIG. 3   a  is a side view of a preferred embodiment that includes expansion sleeves. 
         FIG. 3   b  is a side view of several expansion sleeves of different lengths. 
         FIG. 3   c  is an assembly view of the elongate frame and an expansion sleeve. 
         FIG. 3   d  is a partial cross-sectional view of the elongate frame and an expansion sleeve. 
         FIG. 3   e  is a partial cross-sectional view of the adjustable reference assembly. 
         FIG. 3   f  is a top view of a mounting block. 
         FIG. 4  is a detailed view of a latch mechanism. 
         FIG. 5  is a side view of an alternative embodiment. 
         FIGS. 6   a  and  6   b  show a side view of a preferred embodiment resting against a surface, shown in two deflection states. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention now will be described more fully with reference to the accompanying drawings in which various embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. 
     Referring to  FIGS. 1 and 2 , the preferred embodiment includes elongate frame  1 . Elongate frame  1  is a rectangular tube having a base length of approximately three feet. Bottom surface  1   a  of elongate frame  1  in the preferred embodiment is machined flat. The flat surface forms a first datum surface. End caps  30  and  31  are solid aluminum billets that are sized to fit precisely into the ends of the rectangular channel of elongate frame  1 . In the preferred embodiment, the end caps are epoxied in place and machined flat and perpendicular to bottom surface  1   a . Perpendicularity is important. In the preferred embodiment the end caps are generally perpendicular to bottom surface  1   a . End caps  30  and  31  each contain holes  31   a  and  31   b , sized so that threaded bolts  17  and  18  may extend into the end caps without interference (shown in detail in  FIG. 3   e ). End caps further include guide holes  125  and  130 . Recesses  47   a  and  48   a  are located at each end of elongate frame  1 . Catch support  225   a  resides in recess  47   a . Catch support  226   a  resides in recess  48   a . Each catch support is secured to the elongate frame by way of retaining screws  235  and  240 . Each catch support includes a catch  230  (shown in detail in  FIG. 4 ). 
     By way of example,  FIG. 5  shows the construction of catch support  226   a  and catch  230  as well as the location of the retaining screws  235 . Catch support  226   a  and catch  230  are formed from stamped steel plate in the preferred embodiment. 
     Returning to  FIGS. 1 and 2 , a number of weight reduction holes  4  pass through elongate frame  1 . Center cavity  6  is supplied for mounting of gauge  2 . Elongate frame  1  also includes a set of threaded holes for receiving mounting screws for a set of reference assemblies  15  and  16 . The threaded holes are shown by way of example in  FIG. 3   e  as  120  and  121 . 
     Elongate frame  1  may be made from an extrusion, milled from stock or cast. An aluminum magnesium alloy is preferred for cost and weight considerations. However, elongate frame  1  may be constructed of other rigid materials capable of maintaining a very low central beam deflection for moderate to light loads, on the order of 25 pounds. Lighter weight materials are preferred. For extremely high precision applications, stainless steel or titanium may be employed, resulting in extremely low deflections over large spans. Cross sectional shapes can vary. In one preferred embodiment an “I” beam extrusion is employed having the highest rigidity to weight ratio available. Rectangular and box extrusions are also preferred as having high rigidity. 
     Handle  8  extends from the center of elongate frame  1 . The handle is centrally positioned between the reference assemblies to provide equal pressure to the reference assemblies when in use and to facilitate ease of positioning by a single user. Handle  8  is attached to the elongate frame  1  using screws  8   a  and  8   b  passing through the inside of elongate frame  1  or by welding. Other methods of removable or permanent attachment may be employed as known in the art. A removable handle is preferred to aid in compact storage for shipment. 
     Elongate frame  1  includes two reference assemblies  15  and  16 . Reference assemblies  15  and  16  include mounting blocks  3  and  5 . The top surface of each mounting block (shown by example as  50  of  FIG. 3   f  is machined flat to match the bottom surface  1   a  of the elongate frame. The flat surfaces form second and third datum surfaces from which the device is calibrated. The mounting blocks are removably attached to elongate frame  1  as shown with reference to  FIGS. 1 ,  2 , and  3   e . The mounting blocks include holes  107  and  108 . Bolts  52  and  54  pass through holes  107  and  108  in mounting blocks  3  and  5  and thread into holes  120  and  121  in end cap  31 . Each mounting block includes a threaded hole shown as  17   a  for receiving a threaded contact support, shown as  18 . The threaded contact support  18  is retained in threaded hole  17   a  by locking nut  14 . The threads are standard ASTM pitch. In high precision embodiments, threads with lesser pitch may be employed. 
     Each reference assembly further includes contact pad, shown by example as  9 . In the preferred embodiment, each contact pad includes a flexible neoprene gasket. In other embodiments requiring greater accuracy, each contact pad may be comprised of a suitable rigid material such as nylon, delrin, aluminum or polished stainless steel. In applications where static discharge or contact with high voltage is a concern, the contact assemblies can be formed of bakelite or asbestos. 
     Returning to  FIGS. 1 and 2 , Gauge  2  is operatively positioned in mounting hole  6 . Gauge  2  includes deflection probe  12 , retention knob  10   a  and data read out  10   b . Probe  12  extends radially from the bottom of gauge  2  through access hole  12   a  in elongate frame  1 . Hole  12   a  is sized to avoid interference with the radial movement of probe  12 . Similarly, retention knob  10   a  extends radially through access hole  12   b  in the top of elongate frame  1 . Access hole  12   b  is sized to allow free motion of the retention knob. Probe  12  is spring loaded to facilitate ease of use. Retention knob  10   a  follows the movement of probe  12 . Retention knob  10   a  secures probe  12  to gauge  2  preventing over-extension or loss of probe  12  due to the spring. 
     Gauge  2  in the preferred embodiment is a 543-683B electronic digital indicator manufactured by Mitutoyo of Tokyo, Japan. Another viable option is a depth gauge manufactured under part number CEN44345 and offered for sale by Central Tools/Central Lighting. In another preferred embodiment, the gauge can include an electronic memory including time and date indexing so that the time and date of measurements taken can be recorded. Furthermore, gauge  2  may include a memory for alphanumeric tagging of each measurement so that notes may be made as to the location of the window frame being measured. In this embodiment, electronic downloading of this data is provided to a laptop computer for later use. An RFID tag may be applied to the physical window frame corresponding to the deflection tagging for later positive location and correlation with the deflection measurement. 
     Additionally, gauge  2  may be an optical or acoustic distance measuring device. An example of an optical measuring device is Leica Disto&#39;s model 740690, which measures distance via a laser. An example of an acoustic measuring device is the Intellimeasure model 77-018 from Stanley Tools, which measures distance via ultrasonic waves. Other such measuring devices are known in the art and may include wireless data capture via a computer. Gauge  2  may also include a button to zero the readout at a given height during calibration. 
       FIGS. 3   a - 3   d  and  4  show features extensions  100 ,  105  and  110 . In the preferred embodiment, the extensions are different lengths of 3 inches, 6 inches and 12 inches, respectively. Other lengths of extensions may be utilized. The extensions are attached to the elongate frame singularly or in groups, thereby variably extending the length spanned by the device. Extensions  100 ,  105  and  110  are constructed of hollow rectangular channel having solid ends  101   a  and  101   b ,  106   a  and  106   b , and  111   a  and  111   b . The solid ends are epoxied into each end of each extension, respectively. Bottom surfaces  1009 ,  1089  and  1109  are each machined flat to match bottom surface  1   a  of elongate frame  1 . The bottom surfaces form datum surface for calibration. Each solid end is also machined to be perpendicular with the bottom surfaces. 
     Each extension includes a set of guide pins  115  and  120  and a set of guide holes  116  and  121 . Guide holes  116  and  121  are sized to provide a close fit with guide pins  115  and  120 . Guide pins  115  and  120  are different diameters and different lengths so that the extensions may be assembled with the elongate frame in the proper orientation. 
     In an alternate embodiment, each extension includes a pre-calibrated reference assembly as previously described in relation to elongate frame  1 . 
     As shown in reference to  FIGS. 3   d  and  4 , toggle support  205  resides in recess  47   a  located on each extension. Toggle support  205  is secured in recess  47   a  with bolts  235   a  and  240   a . Toggle arm  245  is pivotally supported by toggle support  205  through hinge pin  215 . Toggle arm  245  includes toggle pin  220  which pivotally supports latch  210 . 
     In situations where a vertical surface has been deflected in more than one plane and/or in more than one location, additional deflection measurements must be taken.  FIG. 5  shows an alternate embodiment which accomplishes this goal. In this embodiment, gauges  51 ,  53 ,  55 ,  57 , and  59  reside in holes  91 ,  93 ,  95 ,  97 , and  99 , respectively. Each gauge includes a retention knob  61 ,  63 ,  65 ,  67 , and  69 , respectively, and a probe  71 ,  73 ,  75 ,  77 , and  79 , respectively. In use, once contact pads  7  and  9  have been positioned, readings from each of the gauges may be taken and recorded simultaneously. 
     The span of the invention may be increased by adding extensions  40 ,  41  at each end of elongate frame  1 . In this case, the guide pins are engaged with corresponding guide holes until one or more extensions meets elongate frame  1 . In order to removably engage an extension with the elongate frame, toggle arm  245  is advanced allowing latch  210  to engage catch  230 . Toggle arm  200  is then rotated forcing latch  210  under catch support  225 , thereby releasably securing the extension to the elongate frame. The mounting blocks, along with the contact assemblies  15  and  16  are removed from elongate frame  1  and attached to extension  40  by use of threaded bolts  52  and  54 . Movement of contact supports  17  and  18  with respect to mounting blocks  3  and  5  is not required and their calibrated height is retained by locking nut  14 . Thus relocation of contact assemblies  15  and  16  onto the extension without recalibration of gauge  2  is accomplished. Other extensions are added in a similar manner. 
     Before use, the device must be calibrated. To calibrate the device, contact pads  7  and  9  are positioned on a flat calibration surface. A gauge block of known height, typically half of the probe&#39;s travel distance, is placed on the flat calibration surface and under the machined bottom surface  1   a  of elongate frame  1 . Contact supports  17  and  18  are adjusted until elongate frame  1  comes to rest on the gauge block. Probe  12  of gauge  2  is spring loaded and provides a measurement of deflection when contact pads  7  and  9  come to rest against the surface. Gauge  2  is adjusted so that the gauge provides a neutral reading of the calibration surface. If additional contact assemblies are included on the extensions, they are attached to elongate frame  1  and calibrated in a similar fashion. 
     Alternatively, the gauge blocks may be replaced by a measurement device. A measurement device, such as a machinist square or a set of calipers is used to determine the distance between contact pads  7 ,  9  and machined bottom surface  1   a . Pads  7  and  9  are then placed against a flat calibration surface and gauge  2  is zeroed against the surface. Alternatively a measuring device may be used to set probe  12  at the same distance as pads  7  and  9 . Probe  12  is then zeroed. 
       FIGS. 6   a  and  6   b  show an embodiment of the invention in use. The device is positioned on a vertical, free standing surface, such as frame  26 . Contact pads  7  and  9  are located at the extremities of the vertical surface and positioned by manipulating the elongate frame by the handle. Spring loaded probe  12  meets frame  26  prior to either contact pad  7  or  9 . As contact pads  7  and  9  move toward the surface, gauge  2  makes a measurement. Generally, the device will be located so that probe  12  meets frame  20  in the center, as this is often the area of greatest deflection. However, the device may be used to measure multiple locations along frame  26 . 
     Where gauge  2  has been properly calibrated, a positive displacement reading will show a deflection of frame  20  inward  22  (away from the device), a negative reading will show a deflection outward  24  (toward the device) and a reading of zero will show no deflection. Where an RFID tag  20   a  is to be employed, it is affixed to frame  20  and its serial number is recorded and correlated with the deflection reading. 
     While preferred embodiments of this device are described as having a manually adjustable gauge, other gauges and measurement devices may be utilized. Further, seals for moving parts are not required for all uses and types of gauges. Finally, zeroing of the gauge and extensions may be accomplished utilizing many methods without departing from the intent and scope of the invention. 
     In the drawings and specification, there have been disclosed embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.