US1825266A - Combination rule and compass - Google Patents

Description

Sept. 29, 1931. A. A. FISCHER PASS Filed Nov. 10 1928 Patentedsept. 29, 1931 UNITED? STATES PATENT OFFICE Lemma 4'. mscm, or nmsnnmm, rumors communon .nULn comes I Application filed November 10, 1988. serial iio. 818,320.

This invention relates to a combination rule and compass and more particularly to a device adapted for use inflayin out'cir cles and lines upon a schoolroom b ackboand or other plane surface. V I

The main object of the invention is the provision of an'adjustable means for de; scribing circles .or arcs thereof which may be :dsed upon the conventional rule or straightnother object of the invention is to pro vide a device of the above mentioned character which will be eflicient in operation and simple, cheap and durable in construction.

With the foregoing and other objects in view the invention resides in the novel construction and arrangement of parts as hereinafter set forth and claimed.

In the drawings: 1 p 7 Figure 1 is a plan view ofthe invention partially broken away.

Figure '2 is an enlarged stion along the line 2-2 in Figure 1.

Figure 3 is a plan view of a modification of the invention, also shown partially broken away; Figure' t is an enlarged section along the line 4- 1 in Figure 3.

The invention consists of a pivotal element denoted generally at 1, the same being rotatably mounted in the rule 2 adjacent one end thereof as shown in Figure 1. The said pivotal 'element 1 comprises the circular metal plate 3 and the circular rubber plate 4 mounted in spaced relationship upon the ends of a tubular spindle 5, the said plates 3 and 4 being rotatably mounted in aligned recesses 6 cut inopposite faces of the rule 2 adjacent one end thereof and the spindle 5.

being rotatably mounted in a bore 7 through the rule and connecting the said recesses 6. Spaced apertures 8 are provided in the rule 2 in longitudinal alignment with and spaced from the pivotal element 1. M i

In the use of the present embodiment of the invention the pivotal element 1 'is positioned over any desired centeror point and heldin place by the finger of the operator, the rubber constructionofvthe circular plate 4=facilitating the holding of the pivotal element upon the proper point, it alsobeing noted that the said rubber plate 4.- projects slightly beyond the face of the rule 2 for this same purpose. A suitable markin device (not shown) such as a pencil or cha is then inserted through one of the apertures 8 and by swlnging'or rotating the .rule 2 upon the said-pivotal assembly 1 a circle or are may be described as will be understood. The tubular construction of the spindle 5 affords a sight aperturefacilitating the proper locating of the pivotal element over the line or point. It will be noted that the pivotal element 1 and apertures 8 are positioned in lateral alignment with certain points upon the scale of the rule 2 so that the length of the radius of the are or circle being described'may be known.

In Figures 3 and 4 is shown a modification of the marking device receiving means for the. rule, the pivotal element (not shown in this view) being identical with that previously described. In this embodiment the rule 7 is provided-with a longitudinally extended slot 9 placed toward that end of the rule opposite to the end in which the pivotal element is mounted. A carrier or slide 10 is provided with grooves 11 in its parallel sides to slidably engage themargins of the slot 9 andthe said carrier is also provided with a medial aperture 12 to receive a suitable marking device (not shown).

The use of this embodiment is the same as that set forth for the first embodiment, the carrier 10 being susceptible of movements to different pointstwithin the slot 9v to permit the drawing of circles of various sizes.

While I have herein set forth certain pre-- ,ferred embodiments of my invention, it is metal plate and a. circular rubber plate rotatably mounted in the recesses in the upper and lower faces respectively of the rule and secured to the ends of the said tubular. spindle. p In testimony whereof aifix my signature.

ARTHUR A. FISCHER.

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