Title:
Combination square and slide rule
United States Patent 2028052


Abstract:
This invention relates to devices for calculating the length of a hypothenuse of a right triangle when the length of one side is known and the rise, per unit in linear measurement of the hypothenuse is known. More specifically, the invention relates to a combination square and slide rule particularly...



Inventors:
Easterly, John I.
Application Number:
US56217131A
Publication Date:
01/14/1936
Filing Date:
09/10/1931
Assignee:
Easterly, John I.
Primary Class:
Other Classes:
33/832
International Classes:
G01B3/56
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Description:

This invention relates to devices for calculating the length of a hypothenuse of a right triangle when the length of one side is known and the rise, per unit in linear measurement of the hypothenuse is known.

More specifically, the invention relates to a combination square and slide rule particularly adapted for use in roof framing for calculating the length of hip, valley, and common rafters, for calculating the difference in length of jack rafters and for calculating the bevel cut on jack, hip, and valley rafters.

The principal object of the invention is to provide a device of this kind which is easy to manipulate and which quickly gives the results sought.

Another object of the invention is to provide a device of this kind which may also be employed as a board measure calculator and as 2o an extension rule.

Still another object of the invention is to provide, in a device of this kind, which includes a slidable member, means for retaining the slidable member against dropping out of the device. Other objects and advantages of the invention will be apparent during the course of the following detailed description, taken in connection with the accompanying drawing, forming a part of this specification, and in which drawing, Figure 1 is a plan view of the device, with a portion broken away, but showing all the novel features of the device.

Figure 2 is an enlarged fragmentary plan view of the device with the slidable portion thereof partly extended.

Figure 3 is a section on the line 3-3 of Figure 2.

In the drawing, wherein for the purpose of illustration is' shown only a preferred embodiment of the invention, the letter A may generally designate the improved device, B a carpenter's square, C 'a slidable portion of the device, and D means for retaining the slidable device against transverse movement.

The improved device is preferably made of rust-proof metal and the lengths of the several parts may vary, as required.

As for the portion B, this preferably comprises two elongated arms or a body portion 4 and 5, at a right angle to each other. Midway between the top edge 6 and the bottom edge 7 of the face 8 of the body portion 4 is a transverse, inverted T-shaped slot or groove .9, extending the entire length of the body portion 4. Preferably adjacent the side or end 10 of the body portion 4 is an arcuate depression II communicating with the upper portion of the slot 9.

At the bottom of the depression and at the axis 00 of the arc is a circular aperture 12 communieating with the bottom of the body portion 4 through a bevel opening 13. The indicia employed in the calculation is engraved or stamped in the face 8 of the body portion 4. Irf addition units of measurement, such as ordinarily appear on a carpenter's square, as for instance, the designations of 1 to 24 inches, generally indicated at 14 may be engraved or stamped in the face 8 of the body portion 4 adjacent the top edge. These are, of course, units of linear measurement and similar units of measurement, indicated at 15, may be engraved or stamped on the face 8 adjacent the bottom edge 7 and similar units on the corresponding face of the body portion 5. The other indicia appearing on the face 8 includes numbered graduations gradually increasing in spaced relation from left to right as shown at 16 and designated as the common rafter scale or as the scale representing the known rise per unit of linear measurement of a hypothenuse. Other numbered graduations increasing in spacing from left to right shown at 17 and designated either as the hip and valley rafter scale, or as the second scale representing the known rise per unit of linear measurement of a hypothenuse, appear on the face 8 but at the opposite edge 'of the slot from the first mentioned calculating indicia. Still a third set of numbered graduations, graduating decreasingly in spaced relation from left to right, shown at 18 appearing on the face 8 may be termed the graduations representing the calculation answer or the sought length of the hypothenuse. At one side, preferably the bottom, of the slot 9 may be provided indicia comprising spaced apart graduations 19 and numerals representing units of linear measurement 19a; these constituting the units employed when extending the sliding body C for use as an extension rule. It is preferred that the portion B be of flexible metal.

As for the sliding body C, this includes an elongated inverted T-shaped body portion 20 having a width, height and thickness sufficient to accommodate it within the inverted T-shaped 4,slot 9 for sliding movement with its upper face 21 level with the face 8 of the body portion 4 and with side walls 22 and 23 abutting the side walls of the invert T-shaped slot 9. Adjacent one end of the body portion 20 is a finger grip ;( or hold 24 cut into the face 21. An arcuate depression 25 in the face 21 forms with the arcuate depression 1 in the face 8 of the body portion 4, a circular depression when the sliding body is wholly within the body portion 4 as is shown in Figure 1. The face 21 carries engraved or stamped indicia, comprising numbered graduations increasing in spaced relation from left to right as shown at 26 and may be termed a run of rafter indicia or indicia representing the known 6g length of units of linear measurement of one side of the right triangle. In addition, an index 27 and an index 28 are provided at the graduation 10 for a purpose later set out. It should also be noted that the sliding body C cooperates with the body portion 5 since the first numeral (I) shown at 29 of the linear measurement scale on the body portion 5 is carried by the sliding body C.. By referring to the indicia designated at 26 on the sliding body and the indicia designated at 18 on the body portion 4 it will be found that one set of graduations is spaced apart in a direction opposite to the spacing apart of the other set of graduations. This portion C, like the portion B, may preferably be of flexible metal.

The means D for retaining the sliding member against transverse movement and which cooperates with the arcuate depression 25, includes a lock head 30 having side walls 31 to be accommodated by the side walls of the depressions I i and 25, and a straight side wall 32 which abuts the side wall 22 of the sliding member C, but does not prevent sliding of the latter. The top surface of this lock head is preferably level with the top surface of the body portion 4 and slide scale 20 and is slotted as at 33. A shank 34 is carried by the head 30 and fits into the opening 12 and terminates at its free end in a beveled portion 35 fitting into the beveled portion 13 of the body portion 4, but loose enough so that the means D carried by the body portion 4 can be easily adjusted either to lock the sliding member in place as shown in Figure 1, or so as to permit the sliding member to be moved transversely as in Figure 2. Thus when the device is being carried about or used as a carpenter's square the means D locks the slide scale in place. The end of a screw driver or the like may be used in the slot 33 to turn the head 30.

In use, if it is desired to employ the device for calculating, the following examples will illustrate this use. Given a roof with a rafter run of 12 feet, a rise of 9 inches per foot, having hip, jacks, and valleys. To find the necessary length of a common rafter:-Move the slide scale C so that the graduations for the numeral 12 (representing 12 feet) of the indicia 26 coincides with the graduations of the numeral 9 (representing 9 inches) of the indicia 16 and the graduations of the indicia 18 (to which the uppermost index 27 points) will be the length of the common rafter. To find the length of hip or valley rafters, move the slide scale 20 so that the graduations for the numeral 12 of the indicia 26 will coincide with the graduations for the numeral 9 of the indicia 17, and the graduations of the indicia IS (to which the uppermost index 27 points) will be the length of the hip or valley rafters. To find the side cut of hip or valley rafters, move the slide scale 20 so that the graduations for the numeral 12 of the indicia 26 will coincide with the graduation for the numeral 9 of the indicia 17, and the graduation of indicia 18 to which the uppermost index 27 points will be the side cut required, 17 being the constant.

By sliding the sliding member 20 towards the right, measurements over 24 inches may be made in running units of linear length for the indicia 19 and 19a last uncovered at the bottom of the slot 9 will show the length of the body portion 4 (24 inches in the example shown) plus the length of the extended portion of the sliding member.

From the foregoing description it will be apparent that a new and efficient device of this character has been disclosed, the manipulation of which will be easily understood, and which will quickly give the answers sought.

Changes in detail may be made to the form of invention herein shown and described, without departing from the spirit of the invention or the scope of the following claims.

What is claimed is: 1. In a device for determining the length of rafters and the bevel cut thereof in roof construction, the combination of an L-shaped carpenter square bearing measuring indicia upon the face of one arm thereof and bearing measuring indicia upon the face of the second arm thereof, said first arm having a groove extending longitudinally thereof and with its end opening into a side edge of the other of said arms, said groove having measuring indicia at the bottom thereof bearing a relationship to a portion of the measuring indicia'upon the face of one of said arms, and a slide scale carried in said groove and having one edge normally extending across said side edge, whereby said edge of said slide scale normally forms a continuation of said side edge, the exposed face of said slide scale being provided with measuring indicia forming in part a continuation of the measuring indicia upon the face of said second arm.

2. In a device for determining the length of rafters and the bevel cut thereof in roof construction, the combination of an L-shaped carpenter square bearing measuring indicia upon the face of one arm thereof and bearing measuring indicia upon the face of the second arm thereof, said first arm having a groove extending longitudinally thereof and with its end opening into a side edge of the other of said arms, said groove having measuring indicia at the bottom thereof bearing a relationship to a portion of the measuring indicia upon the face of one of said arms, a slide scale carried in said groove and having one edge normally extending across said side edge, whereby said edge of said slide scale normally forms a continuation of said side edge, the exposed face of said slide scale being provided with measuring indicia forming in part a continuation of the measuring indicia upon the face of said second arm, and means at the end of said slide scale and square remote from said indicia upon said second arm to releasably lock said slide scale in said groove, said means being operable only when said edge of said slide scale forms a continuation of said side edge of said square.

3. A carpenter's framing square of the class described comprising an arm, a second arm extending perpendicular to said first arm, said first arm being provided with a longitudinal groove extending into a side edge of said second arm, a strip slidably carried in said groove, said strip being movable to a position whereby an edge thereof bridges said side edge and forms a continuous edge along said second arm and means to releasably secure said strip in said position, said means being operable only when said strip is in said position. JOHN I. EASTERLY.