Patent Application
20080042016
Further details of the sidewalk drive shaft mounting are shown. These include a gasket 36, a ball bearing 38, and O-ring 40, a bearing retainer 42, and machine screws and washers 44. These components are used to mount the sidewalk drive shaft. The conventional, one-piece sidewalk gate arm support 46 is fixed to the drive shaft 34 by a woodruff key 48 and held in place by a nut and washer set 50.
These components are enumerated to illustrate the problem with the prior art support arm attachment. As can be seen by the drive train arrangement, the control circuit can be set up to control the motor 14 such that the main gate arm attains a horizontal position when it is closed. Due to the arrangement of the gear train, the sidewalk gate arm will then obtain whatever position is dictated by the engagement of sidewalk drive gear 30 with the segment gear assembly 28. The only adjustment available is to disengage the sidewalk drive gear from the segment gear assembly 28, rotate the sidewalk drive shaft 34 and drive gear combination relative to the segment gear assembly 28, and then re-engage the gears with different sets of gear teeth meshing with one another. As pointed out above, this can result in overcorrection of the problem, leaving no chance to place the sidewalk gate arm in a horizontal position when the main gate arm is in its horizontal position. Further, the disassembly of a nut 50, key 48, support 46, screws 44, retainer 42, O-ring 40, ball bearing 38, and gasket 36 is required to achieve even this coarse adjustment. All those parts must then, of course, be put back together. Overall this is a time-consuming job that will produce indifferent results. Even the most determined installer is likely to be discouraged from even attempting such a task.
The present invention overcomes these problems.
As seen in
The moveable section 56 is an annular disk with a central bore 66 sized for receiving the hub portion 58. The disk has a plurality of arcuate slots 68 cut on the same bolt circle as the bolt holes 64 of the fixed section. Thus, the slots 68 align with the holes 64 when the sections 54, 56 are placed next to one another. A gate arm connector 70 is fixedly attached to the moveable section 56, such as by welding. The gate arm connector may be a weldment or casting having an angled plate 72 and top and bottom flanges 74. The plate may be provided with holes as shown for attachment of a replaceable gate arm extension.
The split hub 52 is assembled by placing the fixed section 54 over the end of the sidewalk drive shaft 34 and pushing the key 48 into place. With the fixed section thus locked on the sidewalk drive shaft 34 the moveable section 56 is slipped over the hub portion 58 of the fixed section 54. Washers 76 and lockwashers 78 are placed on capscrews 80. The capscrews are inserted into the arcuate slots 68 and threaded into the bolt holes 64 of the fixed section. Just before tightening the cap screws the gate arm connector is adjusted to place its free end portion in a horizontal position. The movement of the arcuate slots relative to the cap screws allows this adjustment to take place. With the free end of the gate arm connector horizontal, the cap screws 80 are tightened to lock the mating faces of the fixed section 54 and the moveable section 56 together. When adjusted to the proper position and the cap screws are tightened, the face contact area of the fixed and moveable sections provide enough friction to prevent undesired movement with over 500 ft-lbs applied to the moveable section, which exceeds AREMA main shaft torque requirements.
The split hub components are painted with the exception of the bolt holes, main bores and the contact faces of the fixed and moveable sections. The components may also be zinc plated, galvanized or have no finish if the material is stainless steel.
It will be understood that the embodiments of the present invention which have been described are illustrative of some of the applications of the principles of the present invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention, including those combinations of features that are individually disclosed or claimed herein. For example, instead of the arcuate holes in the movable hub section, the hub sections could have a plurality of radial teeth formed on their adjoining faces. Then the rotational adjustment of the movable section relative to the fixed section would be achieved by loosening the bolts, resetting the mesh of these teeth, and then retightening the bolts. Another possibility would be to clamp the fixed and movable sections together by clamps extending around the outer edges of the hub sections. Also, the above discussion has indicated the primary problem addressed by the invention is positioning of the sidewalk gate arm relative to the main gate arm. However, it will be appreciated that the invention is not limited to use with sidewalk gate arms. It could equally be applied to the main gate arm attachment as well.
