Abstract:
A ladder stabilizer, including: a serrated portion for placement against an object; and the serrated portion being attachable to an upper end of a ladder, with serrations formed on the serrated portion engaging the object.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to ladders generally and, more particularly, but not by way of limitation, to a novel ladder stabilizer that is easily manufactured and used. 
     2. Background Art 
     A ladder stabilizers is provided at the upper end of a ladder to engage an object, typically a pole or a tree, to minimize the possibility of slipping and sliding of the ladder against the object, thus minimizing the possibility of injury to, or the death of, a user of the ladder should slipping or sliding of the ladder occur. Some known ladder stabilizers are described in the following patents. U.S. Pat. No. 6,154,521, issued Nov. 28, 2000, to Campbell, and titled GYRATING ANODE X-RAY TUBE, describes an x-ray tube having a gyrating anode having a convex spherical surface. 
     U.S. Pat. No. 6,185,276, issued Feb. 6, 2001, describes an x-ray tube having a concave, stationary anode U.S. Pat. No. 2,808,975, issued Oct. 8, 1957, to Palmquist, and titled POLE REST ATTACHMENTS FOR LADDERS, describes a ladder stabilizer that, with reference to FIGS. 1 and 2, has an arcuate toothed structure that rests against a pole. The structure is obviously designed for a specific pole diameter, as it could not safely engage a wide range of diameters of poles. 
     U.S. Pat. No. 3,407,900, issued Oct. 29, 1968, to Hopfeld, and titled POLE ENGAGING DEVICE FOR LADDERS, describes a ladder stabilizer consisting of an arcuate strap having what is referred to as “a series of spaced friction projections”. It is not clear that the friction projections would really be of much use. Also, the strap is limited in the range of diameters it could safely accommodate. 
     U.S. Pat. No. 4,349,498, issued Apr. 12, 1983, to Krusmark, and titled SAFETY DEVICE FOR LADDERS, describes a ladder stabilizer that includes an elongated, serrated member that grips a tree or pole. It appears that the range of diameters of the tree or pole is not too limited, but the device includes a number of moving parts. 
     U.S. Pat. No. 4,946,004, issued Aug. 7, 1990, to Henson, and titled POLE GRIPPING LADDER STABILIZING DEVICE, describes a ladder stabilizer that is relatively complicated in that it has moving parts that substantially encircle a pole or tree. It also appears that the device would be somewhat limited in the diameters of poles or trees that could be accommodated. 
     U.S. Pat. No. 5,638,916, issued Jun. 17, 1997, to Schneider, and titled LADDER SAFETY ATTACHMENT, describes a ladder stabilizer that also has moving parts and also appears to be somewhat limited in the diameters of poles or trees that could be accommodated. 
     U.S. Pat. No. 6,244,382, issued Jun. 12, 2001, to Labonte, and titled ATTACHMENT FOR STABILIZING AN EXTENSION LADDER, describes a ladder stabilizer that has many moving parts, although it may be able to accommodate pole or tree diameters in a somewhat greater range than some of the above devices. U.S. Pat. No. 2,808,975, issued Oct. 8, 1957, to Palmquist, and titled POLE REST ATTACHMENTS FOR LADDERS, describes a ladder stabilizer that, with reference to FIGS. 1 and 2, has an arcuate toothed structure that rests against a pole. The structure is obviously designed for a specific pole diameter, as it could not safely engage a wide range of diameters of poles. 
     U.S. Pat. No. 3,407,900, issued Oct. 29, 1968, to Hopfeld, and titled POLE ENGAGING DEVICE FOR LADDERS, describes a ladder stabilizer consisting of an arcuate strap having what is referred to as “a series of spaced friction projections”. It is not clear that the friction projections would really be of much use. Also, the strap is limited in the range of diameters it could safely accommodate. 
     U.S. Pat. No. 4,349,498, issued Apr. 12, 1983, to Krusmark, and titled SAFETY DEVICE FOR LADDERS, describes a ladder stabilizer that includes an elongated, serrated member that grips a tree or pole. It appears that the range of diameters of the tree or pole is not too limited, but the device includes a number of moving parts. 
     U.S. Pat. No. 4,946,004, issued Aug. 7, 1990, to Henson, and titled POLE GRIPPING LADDER STABILIZING DEVICE, describes a ladder stabilizer that is relatively complicated in that it has moving parts that substantially encircle a pole or tree. It also appears that the device would be somewhat limited in the diameters of poles or trees that could be accommodated. 
     U.S. Pat. No. 5,638,916, issued Jun. 17, 1997, to Schneider, and titled LADDER SAFETY ATTACHMENT, describes a ladder stabilizer that also has moving parts and also appears to be somewhat limited in the diameters of poles or trees that could be accommodated. 
     U.S. Pat. No. 6,244,382, issued Jun. 12, 2001, to Labonte, and titled ATTACHMENT FOR STABILIZING AN EXTENSION LADDER, describes a ladder stabilizer that has many moving parts, although it may be able to accommodate pole or tree diameters in a somewhat greater range than some of the above devices. U.S. Pat. No. 2,808,975, issued Oct. 8, 1957, to Palmquist, and titled POLE REST ATTACHMENTS FOR LADDERS, describes a ladder stabilizer that, with reference to FIGS. 1 and 2, has an arcuate toothed structure that rests against a pole. The structure is obviously designed for a specific pole diameter, as it could not safely engage a wide range of diameters of poles. 
     U.S. Pat. No. 3,407,900, issued Oct. 29, 1968, to Hopfeld, and titled POLE ENGAGING DEVICE FOR LADDERS, describes a ladder stabilizer consisting of an arcuate strap having what is referred to as “a series of spaced friction projections”. It is not clear that the friction projections would really be of much use. Also, the strap is limited in the range of diameters it could safely accommodate. 
     U.S. Pat. No. 4,349,498, issued Apr. 12, 1983, to Krusmark, and titled SAFETY DEVICE FOR LADDERS, describes a ladder stabilizer that includes an elongated, serrated member that grips a tree or pole. It appears that the range of diameters of the tree or pole is not too limited, but the device includes a number of moving parts. 
     U.S. Pat. No. 4,946,004, issued Aug. 7, 1990, to Henson, and titled POLE GRIPPING LADDER STABILIZING DEVICE, describes a ladder stabilizer that is relatively complicated in that it has moving parts that substantially encircle a pole or tree. It also appears that the device would be somewhat limited in the diameters of poles or trees that could be accommodated. 
     U.S. Pat. No. 5,638,916, issued Jun. 17, 1997, to Schneider, and titled LADDER SAFETY ATTACHMENT, describes a ladder stabilizer that also has moving parts and also appears to be somewhat limited in the diameters of poles or trees that could be accommodated. 
     U.S. Pat. No. 6,244,382, issued Jun. 12, 2001, to Labonte, and titled ATTACHMENT FOR STABILIZING AN EXTENSION LADDER, describes a ladder stabilizer that has many moving parts, although it may be able to accommodate pole or tree diameters in a somewhat greater range than some of the above devices. 
     None of the above devices is simple and has no moving parts. Additionally, most of the above devices cannot accommodate a relatively wide range of diameters of objects. 
     Accordingly, it is a principal object of the present invention to provide a ladder stabilizer that can be economically manufactured and easily used. 
     It is a further object of the present invention to provide such a ladder stabilizer that can accommodate a relatively wide range of diameters of objects. 
     It is an additional object of the present invention to provide such a ladder stabilizer that has no moving parts. 
     It is another object of the present invention to provide such a ladder stabilizer that can be quickly attached to or removed from the end of a ladder. 
     Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figure. 
     SUMMARY OF THE INVENTION 
     The present invention achieves the above objects, among others, by providing, in a preferred embodiment, a ladder stabilizer, comprising: a serrated portion for placement against an object; and said serrated portion being attachable to an upper end of a ladder, with serrations formed on said serrated portion engaging said object. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Understanding of the present invention and the various aspects thereof will be facilitated by reference to the accompanying drawing figures, provided for purposes of illustration only and not intended to define the scope of the invention, on which: 
     FIG. 1 is an isometric view of the ladder stabilizer of the present invention, attached to the upper end of a metal ladder, and placed against an object. 
     FIG. 2 is an exploded isometric view of the ladder stabilizer, the upper end of the metal ladder, and hardware for attaching the ladder stabilizer to the upper end of the metal ladder. 
     FIG. 3 is an isometric view of the ladder stabilizer attached to the upper end of the metal ladder. 
     FIG. 4 is a top plan view of the ladder stabilizer attached to the upper end of the metal ladder, showing the wide range of diameters of objects that can be accommodated by the ladder stabilizer. 
     FIG. 5 is an alternative embodiment of the present invention for use with a wooden ladder. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference should now be made to the drawing figures on which similar or identical elements are given consistent identifying numerals throughout the various figures thereof, and on which parenthetical references to figure numbers, when used, direct the reader to the view(s) on which the element(s) being described is (are) best seen, although the element(s) may be seen on other figures also. 
     FIG. 1 illustrates a ladder stabilizer, constructed according to the present invention, and generally indicated by the reference numeral  10 . Ladder stabilizer  10  is illustrated as attached to the upper end of a metal ladder  20  and is placed against an object, in this case a tree  22 . It will be noticed that ladder stabilizer  10  includes a plurality of serrations, as at  30 , which serrations engage the tree and minimize the possibility of the slipping or sliding of metal ladder  20 . 
     FIG. 2 illustrates the means of attachment of ladder stabilizer  10  to the upper end of metal ladder  20  and includes four threaded bolts, as at  40 , inserted through four holes, as at  42 , defined through the ladder stabilizer and aligned with four holes, as at  44 , defined through flanges  46  on metal ladder  20 . One each of four tapered bearing blocks, as at  60 , is provided on either side of the non-serrated portion of ladder stabilizer  10  to provide for the proper placing of the non-serrated portions of the ladder stabilizer against the upper end of metal ladder  20 . Eight flat washers, as at  70 , (only six shown on FIG. 2) and four locking nuts, as at  72 , (only two shown on FIG. 2) complete the hardware for attaching ladder stabilizer  10  to the upper end of metal ladder  20 . 
     Continuing to refer to FIG. 2, the non-serrated portions of ladder stabilizer  10  are bent upwardly from the plane of flanges  46  of metal ladder  20  at an angle α of about 20 degrees. Thus, the ends of the serrated portions of ladder stabilizer  10 , being disposed roughly orthogonally to the non-serrated portions of the ladder stabilizer are also bent upwardly about 20 degrees from the plane of flanges  46 . Serrations  30  can be spaced apart about 1-½ inches and can be about 1-½ inches high, although serrations  30  having other dimensions and ladder stabilizers having other angles may be provided as well within the contemplation of the present invention. Serrations  30  on the two serrated portions of ladder stabilizer  10  are roughly aligned. 
     FIG. 3 illustrates more clearly ladder stabilizer  10  attached to the upper end of metal ladder  20 , with the elements of the ladder stabilizer and the means for attachment of the ladder stabilizer to the upper end of the metal ladder are as is described above (FIG.  2 ). 
     FIG. 4 illustrates that ladder stabilizer  10  having the above dimensions (FIG. 2) can accommodate a wide range of diameters of objects, here a ratio of diameters of about at least 4 to 1. Other dimensions and angles can be provided to accommodate other diameters. 
     FIG. 5 illustrates an embodiment of the present invention for use with a wooden ladder  20 ′. Elements of ladder stabilizer  10 ′ shown on FIG. 5 that are identical to the elements of ladder stabilizer  10  (FIG. 2) are given identical reference numerals. Elements of ladder stabilizer  10 ′ that have a different form, but similar function to that of ladder stabilizer  10  are given primed reference numerals. The primary difference between the embodiment shown on FIG.  5  and the embodiment shown on FIG. 2 is that four bolts, as at  40  (FIG.  2 ), have been replaced with four lag crews, as at  40 ′. Also, four circular holes, as at  42  (FIG.  2 ), have been replaced with four slots, as at  42 ′, for slight lateral adjustment of ladder stabilizer  10  on ladder  20 ′. Such slots could also be provided on the embodiment shown on FIG. 2 or, alternatively, circular openings  42  could be provided on ladder stabilizer  10 ′. 
     Ladder stabilizer  10  or  10 ′ can be economically constructed of any suitable metallic or engineering plastic material using conventional methods of manufacture. 
     In the embodiments of the present invention described above, it will be recognized that individual elements and/or features thereof are not necessarily limited to a particular embodiment but, where applicable, are interchangeable and can be used in any selected embodiment even though such may not be specifically shown. 
     Terms such as “above”, “below”, “upper”, “lower”, “inner”, “outer”, “inwardly”, “outwardly”, “vertical”, “horizontal”, and the like, when used herein, refer to the positions of the respective elements shown on the accompanying drawing figures and the present invention is not necessarily limited to such positions. 
     It will thus be seen that the objects set forth above, among those elucidated in, or made apparent from, the preceding description, are efficiently attained and, since certain changes may be made in the above construction and method without departing from the scope of the invention, it is intended that all matter contained in the above description or shown on the accompanying drawing figures shall be interpreted as illustrative only and not in a limiting sense. 
     It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.