Geometrical instruments – Straightedge type – Cord type
Reexamination Certificate
2002-09-30
2004-03-16
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Straightedge type
Cord type
C033S770000, C033S758000, C007S119000
Reexamination Certificate
active
06705018
ABSTRACT:
BACKGROUND
1. Field of the Invention
This invention relates to hand tools and, more specifically, to a chalk line device.
2. Description of Prior Art
In many fields, especially in most phases of building and construction, the chalk line can be used to strike a near perfect line on any uniformly flat surface. The chalk line, sometimes referred to as a “chalk box”, has been around for some time with very few design changes or improvements. It consists of a length of string, a hollow housing containing a reel to collect this string attached to a crank outside of the housing, and a flat hooked tab that usually contains a tear-shaped aperture. For the purposes of this discussion, this hooked tab and the like will be referred to as a “chalk line end”. The hollow housing is full of colored chalk, which coats the string when it is drawn out through a small hole in the housing.
To operate the chalk line system, the user first hooks the chalk line end over the edge of a sheet of material at a predetermined point, looking through the aperture to center the chalk line end on his mark. Then he unreels the string line as he stretches it across the material's surface, pulling it taut and holding it to the surface with one hand at a second predetermined point. With his other hand the user grasps the string line between thumb and finger a distance from where he is holding it to the surface, lifts it off the surface around six to eighteen inches and quickly releases it. The string line snaps back down onto the surface with some force, and when it is removed and re-reeled a straight, clear line of colored chalk is left on the material's surface connecting the two points. This process is often referred to as “popping a line”.
The chalk line is a very useful tool in many fields, but in its present embodiment it is not without its limitations. For the purposes of this discussion, only limitations of the standard or “prior art” chalk line end, and not the entire chalk line system, will be disclosed in the interest of simplicity. The standard chalk line end can be used in the pre-described manner only if the line to be popped is at or very near a ninety-degree angle to the edge of the surface, and if the edge is clean and defined (not rounded, tapered or otherwise imperfect). If either of these conditions is not met, the standard chalk line end will almost always slip from the edge of the material.
The user can solve this problem in several ways. He can have a helper hold the end of his string line on the mark while he pulls it taut and pops the line. If no one is available to help, however, the user still has other options. The standard chalk line end has a tear-shaped aperture directly centered, with its narrowest end pointing toward the hooked tab of the chalk line end. The largest end of this aperture is easily wide enough to allow the head of a twelve or sixteen penny nail to pass through. This allows the user to drive a nail at an angle into the material, slide the chalk line end over the nail and pull the string line taut without the aid of a helper. Or, the user has the option of cutting a small notch into the material's edge with a knife or saw, then sliding the chalk line through the notch until it catches, thereby holding it on the mark.
However, all of these solutions are inconvenient and time-consuming, leading some to seek to design a more utilitarian chalk line end. Only two recent inventions attempting to accomplish this or anything similar could be found, disclosed in U.S. Pat. Nos. 6,082,014 to Beyers (2000) and 6,138,370 to Rolfe (2000). With no disrespect to the inventor intended, Beyers' chalk line end is large and bulky, as far as chalk line ends are concerned. Also, it bears little resemblance to its predecessors, thus losing the advantage of familiarity. And, while it can be used to pop lines off the surface edge at angles other than ninety degrees, it cannot be used in many of the ways that the standard chalk line end can be. This means that at some point the user would have to cut Beyers' chalk line end from the string line and replace it with a standard end to perform many tasks. In addition, Beyers' invention does little to address the issue of surface edge quality.
Rolfe's invention is not a chalk line end at all, but a instead a chalk line helper, as it is not attached to the string line in any way. However, it is included in the interest of thoroughness, as it serves as an anchor for a chalk line. Though it could be considered to have a similar purpose as the presently disclosed invention, there is nothing remotely similar in either their structure or method of operation. Not only is Rolfe's chalk line helper a separate entity from the chalk line itself, but the device must also be set and removed with a claw hammer or other such means, thereby involving the use other tools and thus making the process more complicated. In addition, the device's main goal is to facilitate the popping of parallel lines a particular distance apart (such as to define the area of a two-by-four wall), which it seems quite capable of doing well. So, in the end, Rolfe's chalk line helper has a significantly different main goal from that of the present invention, and is sufficiently different in structure as well.
SUMMARY
The invention, a modified chalk line end with retractable blade, in its preferred embodiment, consists of a flat, tapered, semi-rectangular main body made up of two flat members shaped somewhat like a standard chalk line end, bent and fused together along one of their corresponding long edges. At one end of the main body, one or both of the members are bent at least once to form a hooked tab that is essentially perpendicular to the main body. At the other end there is a small, round aperture through which the string line is threaded and tied off. There is another larger, tear-shaped aperture in the main body (in both members) with its narrowest end pointing toward the hooked tab, which allows the invention to be slid over the head of a driven nail and be held fast. This aperture also serves as a window through which the user can see and center the chalk line on the mark.
However, the invention has a new and significant feature. The two members that form the main body are set at a slight distance from each other, and between them there is a single-edged blade, attached to the main body towards one end by a pivotal connector, such as a rivet. This blade contains the same tear-shaped aperture as the main body, these apertures essentially aligning when the blade is completely inside the main body. It also has a pull tab or other device to allow the user to grasp and rotate the blade out from the main body somewhat like a pocketknife. The blade is stopped by a fused section of the main body members or a stop attached to the main body, when the blade edge is at an approximate ninety-degree angle to the long, open edge of the main body.
The normal position of use for a standard chalk line end (when it is used to engage a square, defined edge) is with the hooked tab pointing essentially downward and the main body flat on the top surface of the sheet of material. The present invention can be used in the previous manner, as well as in a new and novel way. If the user encounters a rounded or otherwise imperfect edge, or if the line to be popped is at an angle other than an approximate ninety-degree angle to the edge of the sheet of material, he now has a new option. First, the user must first swing the blade completely out from the main body, as described in the previous paragraph. Next, he rotates the blade around ninety degrees from the aforementioned normal position of use, using the chalk line as an axis. Then, instead of securing the invention to the edge using the hooked tab as before, the user engages the edge by the blade, which sets itself into the material when the chalk line is pulled back upon. He now can pop a line on a sheet with a rounded edge, or off the edge of a sheet at most any angle he chooses. In addition, using the
Cohen Amy R.
Gutierrez Diego
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