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US 4,538,352 AGranted
Shrinkage compensated measuring device
AssigneeNone recorded
InventorDonald E. Frith
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AssigneeNone recorded
InventorDonald E. Frith
Estimating the term…
The disclosure describes a shrinkage compensated measuring device comprising a first scale calibrated in units of length, e.g., inches or centimeters, and a second scale calibrated in units of percent shrinkage. Each point on the second scale corresponds to a unique point on the first scale and indicates the percent difference between a reference point on the first scale and the unique point on the first scale. The shrinkage device also comprises a first array of lines, each line of the first array corresponding to a unique percent shrinkage, and a second array of lines extending across the first array such that the distance between any two lines of the second array as measured along one of the lines of the first array is inversely proportional to one minus the percent shrinkage corresponding to that line of the first array divided by one hundred.
A shrinkage device comprising a flat body member, a first scale on the flat body member calibrated in units indicative of length, the scale including an initial point and a reference point spaced from the initial point and each point on the first scale indicative of the distance from that point to the initial point, a second scale on the flat body member calibrated in units indicative of percent shrinkage, each point on the second scale corresponding to a unique point on the first scale wherein a line passing through a point on the first scale and the corresponding point on the second scale is parallel to a line passing through any other point on the first scale and the corresponding point on the second scale, the second scale including a reference point which corresponds to the reference point on the first scale, the distance between the reference point on the second scale and a second point on the second scale being indicative of the percent difference between the distance indicated by the reference point on the first scale and the distance indicated by the point on the first scale to which the second point on the second scale corresponds, a first array of lines on the flat body member, each line of the first array corresponding to a unique percent shrinkage, and a second array of lines on the flat body member intersecting the first array of lines, the distance between two successive lines of the second array as measured along any one line of the first array being inversely proportional to one minus the percent shrinkage corresponding to that one line of the first array divided by one hundred, whereby the percent shrinkage determined from the first and second scales may be compensated for by the distance between successive lines of the second array as measured along the line of the first array corresponding to that percent shrinkage.
Dependencies are inferred from the claim text.
No related US applications are recorded in the indexed filing history.
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Term ended 22 Nov 2003 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to measuring devices. More specifically, it relates to measuring devices which compensate for shrinkage.
During many fabricating or manufacturing processes, the piece being processed (i.e., the workpiece) shrinks. For example, a piece of porcelain typically shrinks anywhere from 12 to 16 percent during firing in a kiln. To produce a finished piece having specific dimensions, it is important to determine the exact amount the workpiece will shrink during processing and to increase the pre-processing dimensions sufficiently to allow for the determined shrinkage.
Many factors affect the exact amount of shrinkage, including the composition of the material from which the workpiece is fashioned, the size of the workpiece and the conditions under which the workpiece is processed (e.g., temperature, humidity and duration). Consequently, the amount of shrinkage can vary from the workpiece to another and from one process to another. Ideally, there should be some means to determine the exact amount a particular workpiece will shrink during a particular process.
In the accompanying drawings:
FIG. 1 is a plan view of the front side of a shrinkage device of the present invention and
FIG. 2 is a plan view of the back side of a shrinkage device of the present invention.
An exemplary device 100 which embodies the present invention comprises a thin rectangular plate fashioned from a plastic or other suitable material and having a front side 101 as shown in FIG. 1 and a back side 102 as shown in FIG. 2. The front side 101 is used to determine the amount that a testpiece of a certain material (e.g., a porcelain ceramic) will shrink during a particular processing operation (e.g., firing in a kiln). The back side 102 is used to create a scale calibrated in standard units of length (e.g., inches) but having a distance between successive unit designations greater than the standard unit by an expansion factor defined according to the determined shrinkage. For a workpiece which is of a similar material to that of the testpiece and is to undergo a similar processing operation, the scale may be used to establish pre-processing dimensions which will shrink during the processing operation to desired post-processing dimensions.
As shown in FIG. 1, the front side 101 of the device 100 has first and second edges 103, 104 comprising first and second scales 105, 106, respectively. In this preferred embodiment, the first scale 105 is calibrated in 10 inches having one inch between successive inch designations, and the second scale 106 is calibrated in 10 centimeters having one centimeter between successive centimeter designations. However, either scale 105, 106 may be calibrated in any number of any units of length having a single unit distance between successive unit designations without departing from the scope of the invention.
A first oblique line 110 extends across the front side 101 at an acute angle to the first edge 103, intersecting the first edge 103 at a reference point on the inch scale 105, which in this preferred embodiment is the 10-inch designation. This first oblique line 110 comprises a scale 111 which is calibrated in percent shrinkage and which relates directly to the inch scale 105. Each point on the percent shrinkage scale 111 corresponds to a unique point on the inch scale 105 and indicates the percent difference, i.e., the percent shrinkage, between the reference point, i.e., ten inches, and the unique point on the inch scale 105. For example, the percent shrinkage scale 111 indicates that nine inches is 10 percent less than 10 inches, as determined by the perpendicular 112 from the nine-inch designation on the inch scale 105 to the percent shrinkage scale 111. A second oblique line 113 similarly extends across the front side 101 at an acute angle to the second edge 104, intersecting the second edge 104 at a reference point on the centimeter scale 106, which in this preferred embodiment is the 10-centimeter designation. This second oblique line 113 also comprises a scale 114 which is calibrated in percent shrinkage and which relates to the centimeter scale 106 just as the percent shrinkage scale 111 along the first oblique line 110 relates to the inch scale 105.