Abstract:
A method and device for elevator rail point alignment. A device body has a rear rail clamp and a front, angle alignable laser device. The laser mount provides for inversion alignment. In use, the device can be simply brought into true aim by focusing on an opposite target and marking the beam spot, inverting the tool on a aim and marking a second beam spot, and reaiming the laser to an intermediate spot.

Description:
TECHNICAL FIELD 
   The present invention relates to elevator installation and more specifically a device for accurately pointing elevator rails. 
   BACKGROUND ART 
   A number of factors have led to the development of high performance elevators. Taller buildings and increased passenger traffic requires efficient elevator systems to convey passengers between floors. This requires advanced, faster elevators with a sophisticated system for powering and controlling the elevator. This has resulted in elevators having ever increasing vertical operating speeds. However, such faster travel speeds have led to a number of technical challenges. One such technical challenge is the need for precisely aligned guide rails. These guide rails, upon which the elevator cars move vertically, must be aligned to exacting tolerances. If the opposing rails are not aligned this could be detected by passengers riding in the elevator car as vibration. This may result in passenger discomfort and wear and tear on elevator parts. 
   To alleviate these problems in elevator operation, the rails must be positioned as linear and parallel to one another as is practical. A number of different devices have been employed to ensure proper orientation of the elevator rails on the vertical services within elevator shafts. In one common technique, a plumb line may be hung adjacent to the brackets onto which the guide rails are mounted. This plumb line may then be used to ensure proper orientation of the rail from top to bottom. This is referred to as “plumb alignment”. 
   A second device may be used to ensure orientation of the point of the rails. This ensures that each elevator guide rail is positioned such that it properly faces the opposite guide rail. This is referred to as “point alignment”. 
   U.S. Pat. No. 4,593,794 provides an illustration of one such rail orientation device. The term used herein to describe the pointing of rails such that they face each other is “point leveling”. 
   U.S. Pat. No. 4,593,794 discloses an apparatus for installing elevator rails in a linear and parallel orientation. The device disclosed includes a pair of mirror image guide clamps which each attach to one opposite rail. These guide assemblies have a reference notch which positions the rail relative to an adjacent plumb line. The device also includes an inner connecting guideline which ensures that the point orientation of the rails of the rail clamp location is aligned. This requires attaching a guide to each rail and having a string extend between the two guides. Thus for proper rail point alignment at least two guides must be clamped to opposite rails, a string extends across the elevator shaft, and additional tools are required for plumb alignment. The combination of multiple clamps and multiple strings allows both plumb and point alignment using this tool. 
   A number of drawbacks exist for the use of string-based alignment. First, the alignment of point requires a rail installer to move back and forth between the two rails making multiple adjustment to each string guide. Secondly, the string is somewhat cumbersome. The string extends across the elevator shaft and the installers must move around a string extending across the elevator shaft. 
   One of the present objects is to design a elevator rail point alignment tool that requires only one device be attached to a rail for point alignment. 
   SUMMARY OF THE INVENTION 
   The above objects and other objects are achieved with a device for point alignment of elevator rails. This device includes a rail clamp body on which a laser mount is attached. A laser is mounted on the laser mount. The laser mount also includes means for adjusting the laser mount. This means for adjusting the laser mount may be configured to allow for inversion calibration. In some embodiments, the means for adjusting the laser mount may include an adjustable spring tensioning device and a central pivot attaching the laser mount to the rail clamp body. In some embodiments the means for adjusting the laser mount may include a locking fastener on the laser mount mounted in a track. In other embodiments the rail clamp body may include an adapter configured to allow the device to be used on rails having differing thicknesses. 
   Another embodiment of the invention is a method for adjusting the laser level. This method would include clamping a laser level to a vertical rail and activating the laser level such that the laser level is upright and horizontal and directed onto a second elongate vertical rail. The beam spot would be directed onto a flat vertical surface of a rail preferably at a rail clamp location. The location of the initial beam spot is marked on the second rail and then the laser level is inverted. The new beam spot location is marked on the second rail and the laser aim is adjusted such that the beam spot is located between the first and second marked spot locations. This new intermediate spot is then marked and the laser level is once again inverted. If the device has been properly aligned the beam spot will remain at this third beam mark location. If not, the laser level may once again be inverted the new spot marked and the device further adjusted. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top view of an embodiment of the point laser level alignment tool. 
       FIG. 2  is a cross sectional view of an elevator rail. 
       FIG. 3  is a top view of a laser level tool shown mounted on a rail cross section with a beam generated by the laser level tool directed at a second rail. 
   

   DETAILED DESCRIPTION 
   With reference to  FIG. 1  the laser alignment tool  10  includes a rail clamp body  11  onto which other elements are mounted. A nose section  12  on rail clamp body  11  projects providing a laser support surface. Mounted onto rail clamp body  11  is a laser mount  14 . Laser  40  is mounted to laser mount  14  at the location of attachment  16  which attaches laser  40  to mount  14 . The laser  40  is fixedly mounted to laser mount  14  such that the longitudinal axis of laser  40  is substantially perpendicular to laser mount  14 . Laser mount  14  is attached to a floating pin  19  that extends into an internal cavity (shown in cutaway) in block  12 . A spring  100  is set into a blind hole and biases one side of pin  19 . An Allen screw  18  having adjustment head  17  is driven into a threaded hole in block  12  below laser mount  14  and pushes against an opposite side of pin  19 . 
   At the opposite end of laser mount  14  is a adjustment arc track  21  which extends through laser mount  14 . An adjustment lock fastener  20  extends through adjustment arc track  21  and may be bolted into rail clamp body  11 . Adjustment lock fastener  20  may be loosened allowing pivoting of laser mount  14 . From this configuration it should be apparent how the laser might be adjusted. Adjustment lock fastener  20  may be loosened and the laser mount  14  would pivot on pivot  16  changing the aim of laser beam  42  emitted by laser  40 . This would allow side to side adjustment of a beam aim. The tensioner would allow more simplified incremental movement of laser mount  14 . Adjustment screw  17  may be tightened, increasing the tension of spring tensioner  18 . 
   A number of alternative means for adjusting the laser mount are possible. For example, a ring group of pins on laser mount  14  could be received into a ring group of holes in rail clamp body  11 . This would allow physical manual adjustment of the laser mount. Alternatively, various ratcheting mechanisms, magnetic mechanisms, and other adjustment means are contemplated. 
   Rail clamp body  11  also has a first rail mount arm  22  and a second rail mount arm  24  which define a rail receiving space  26 . This is the location where the alignment tool  10  is secured to an elongate elevator rail. With reference to  FIG. 2  the elongate rail  50  is shown in cross section. The present device is clamped between the face  52  and face  54 . An opposite rail has a flat surface  56  onto which the laser is aimed. 
   Returning to  FIG. 1 , to allow tightening to the rail knob  28  is received through a threaded hole extending through second mount arm  24 . This allows knob  28  to be rotatably tightened against the rail. Alternative clamping devices including spring mounted pins and other fasteners may be used. 
   Because the elongate rails may be of different sizes an adapter may be fitted into the rail clamp body  11 . In  FIG. 1 , rail size adapter  30  is shown secured onto rail clamp body  11  by adapter mount bolts  32 ,  34 . Adapter  30  is mounted on first rail mount arm  22  opposite the knob  28  mounted on second rail mount arm  24 . Thus when the alignment tool  10  is mounted on a rail the laser is centered on the tool at the rail center. 
   The present tool is used to align elevator t-rails, specifically point alignment of elevator t-rails. The tool does not align or position the rails in the hoistway. Plumb alignment may be performed with a number of other tools, including plumb lines. Instead, the present tool is used to point rails at each other. With the present adapter the present alignment tool may be used on a number of different sizes of elevator t-rails. Different adapter blocks may be exchanged to accommodate a variety of different size rails. The primary purpose of this tool is to align the face of a king t-rail parallel to the face of a queen t-rail. Aligning the face of both t-rails parallel to each other is referred to throughout as point alignment. With reference to  FIG. 3 , a king rail  52  and queen rail  60  are shown. The alignment tool  10  is mounted to king rail  62  on faces  64 ,  66  the laser  40  mounted on laser mount  14  produces laser beam  42  directed at target surface  61  on queen rail  60 . 
   In the alignment process, first the correct adapter is inserted into the rail clamp body. The adapters selected for the thickness of the rail that is being aligned. This will ensure that the laser spot on the center line of the post on the opposite rail is correctly centered. 
   The alignment tool is clamped such that the laser is upright and horizontal on king rail  62  as shown. The device is turned on and the location of the laser dot on the queen rail is marked. The tool is then inverted 180%, resecured to the king rail  62  and the new position of the laser spot on the queen rail is marked. If the first spot location is different from the second spot aim is adjusted the adjustment screws are loosened and the laser is repainted such that the spot is at a third position halfway between the first and the second position. The screw is retightened and clamp is once again inverted. If the laser spot does not change from this third position then the laser is aimed true and parallel to the face of the rail that its clamped onto. If the laser spot is in a different position the laser is again realigned by marking the spot and moving to halfway between this fourth spot and the third spot. 
   Once the laser has been properly adjusted and centered it is clamped onto the king rail and turned on. The king rail is then positionally adjusted on its mounting fasteners until the laser dot is in the center of the queen rail post face. At this point the rail bracket is tightened. The alignment tool is then taken off of the king rail and moved onto the queen rail where the laser is upright and horizontal. The queen rail is then turned until the laser dot is in the center of the king rail post and then the queen rail is tightened onto the rail bracket. The alignment tool may then be moved back to the king rail to verify accuracy and then back to the queen rail to verify accurate of point alignment.