Sept» 10, 1946- . . G. J. HENJUM DEVELOPMENT AND LAYOÄJÍIl INSTRÜIMENT 2,407,368l Filed May _22, 1945 INVENroA GERALD J. HENJUM BY www Attorney 2,407,368 Patented Sept.v l0, 1946 UNITED STATES -PATENT oFFlcE DEVELOYPMENT AND LAYOUT INSTRUIVIENT Gerald J. Henjum, Hollywood, Calif., assîgnor of one-third to Albert H. Farness, North Holly wood, and one-third to Chester H. Sherer, Los Angeles, Calif. Application May 22, 1945, Serial No. 595,109 4 Claims. (Cl. 33-.-104) l 2 This invention relates to a new and improved The practical embodiment chosen for illustra drafting instrument for developing flat patterns tion comprises a draftsman’s triangle lil of con of the‘intersection of surfaces of revolution such as pipes used for ñuids, and standards or mount ings wherein it is desired to develop a Wrap arcund‘template or pattern to facilitate the cut ting of the end of a pipe, as when it is desired vto attach a branch pipe'v to another pipe at any ventional outline, having the usual central open ing Il whereby the inner edges of the side por tions l2, I3 and i4 are parallel to the external angle thereto. , edges. In addition, I have sho-Wn a protractor arc l5 having suitable indicia, this feature being useful in setting out the desired anglesat which thepipes `are to be joined. The coordinated series of scales as shown and By well known mechanical drafting processes, hereinbefore referred to, are grouped in vari familiar to engineering draftsmen, it is possible ous standard pipe sizes, which as is well known, to develop such intersections and patterns or are rated as the nominal inside diameters, vary templates on the drawing board, with the use ing in this case from one and one-quarter inches of Yconventional drafting instruments. Such processes are responsible for considerable delayV 15 to eight inches. In each standard size, I show a scale Yiii marked ID (inside diameter) which in'ñeld and shop work, where the Welder or sheet metal worker desires to do the job on the spot. It is, therefore, an object of this invention to provide a layout instrument capable of use by represents the successive projections on a diam eter of arcs of twenty-two and. one-half degrees, i. e., a semi-circle is divided into eight equal a mechanic for developing such intersections as 20 parts, and the projections of these points on the diameter form the scale. For convenience needed, at a great saving of time as compared I show only four points plus the center line l'! to conventional mechanical drawing procedures. for a ninety degree arc, as the other four points The use of my herein described instrument elim can be obtained by reversing the triangle and inates the need of computations and the use of conventional drafting instruments, as I provide 25 scale. A second scale I8, marked OD (outside diameter) covers four points running the other a »series of scales for each standard pipe size to enable the workman to complete the develop ment or layout of a wrap-around pattern or tem way‘from the center line Il, and corresponds to the actual outside diameter of standard pipe of thenominal inside diameter specified. In order plate, Which can be applied directly to the end of ’the pipeto be cut'or beveled to lit against 30 to develop a flat pattern of the circumference of a »pipe of given nominal size, I provide a third » another pipe at the angle and/or offset contem scale I9, marked X, which gives the actual de plated. It is also sometimes convenient to de veloped length of the arcuate segments divided velop a wrap-around template to transfer the as in producing the OD scale I8. outline of the hole to be cut in the pipe to which In order to be able to strike arcs correspond-' the branch is to be applied, and this can read 35 ing to the actual outside diameters of the sev ily be done with the instrument of my invention. ` eral nominal pipe sizes, I provide a series of per With these and other objects in view, as will more fully appear as the description proceeds, forations 20, one oi’ which is marked as the center drawing wherein: shortened. O, and the others positioned at the correspond my invention consists in the construction, novel features and combination of scales hereinafterk 40 ing radii and marked for the nominal pipe sizes. Inthe use of my layout instrument, the usual more fully described, pointed out in the claims mechanical drafting procedure is materially appended, and illustrated in the accompanying In the simplest case of a right an gled joint between equal sized pipes, it is only Figure 1 is a View of one side of a triangle embodying the features of this invention; and, 45 necessary to draw two lines at forty-five degrees and to carry the projections of the OD and ID Figure 2 isa view of the other side thereof. scales normal to one line to their intersection While I have chosen to illustrate my inven with the other lines, and measure their length tion as incorporated in a triangle similar in out on the forty-five degree line, transferring these line to a conventional draftsman’s triangle, it is to be understood that the exact proportions 50 lengths to ordinates erected at intervals deter mined by the X scale to develop the layout or and/or shape of the instrument is immaterial to wrap-around template for cutting the ends of the the principles of my invention, since my coordi nated series of scales can be applied to other con pipe. Y In a more complicated case of unequal pipe figuratif-ns without affecting the usefulness 55 sizes, when the branch may be both offset and at thereof. ` g 2,407,368 3 ¿i a specified angle to the main run of pipe, the flexible sheet metal either for transfer direct to procedure is a trifle more complicated, but still the pipe, or as a template for contouring a collar basically straightforward and readily apparent to serve as a guide for cutting the ends of a numn to those skilled in the art. ber of pipes to the same pattern. In order to determine the ordinates to be applied to the layout or Wrap CTI Obviously, my invention is susceptible of em around template lines determined by the X scale bodiment in forms other than that chosen for for the branch pipe line, it is necessary to draw illustration herein, and applicable to other and a base line and strike an arc of the OD of the analogous uses than pipe welding and/or assem main run tangent thereto. The amount of off bling, and I therefore do not desire to be limited set is marked from the point of tangency and the 10 other than by the permissible scope of the claims appended hereto. ID and OD scales centered on the offset, the scale markings being carried down to the arc pre I claim: viously marked, and then carried` out parallel to the base line. The branch pipe center line is drawn at the desired angle and the ID and OD scales marked normal thereto,` being carried down parallel to the center line ofthe branch pipe to intersect the corresponding lines parallel to the base line ñrst drawn. The lengths of thelines parallel to the center line of the branch pipe 20 form the ordinates of the developed or wraparound template. Y I find it desirable to use the ID scales for the “open” sides of the branch pipe, and the OD scales for the “closed” sides of the pipes, since by so doing the necessity of beveling the cut ends of the pipe isy avoided, and in addition, a V is left for the welding material, in the case of standard pipe which has appreciable Wall thick ness. If working with thin-walled tubing or _ sheet metal, such as stove pipe, the outside di ameter is also practically the nominal pipe size, and both ninety degree arcs can be laid out from the ID scales by reversing the triangle about the center line of the scale. However, the illustrated embodiment of the developed length scale I9 allows for appreciable pipe thickness, so that for thin metal the spacings of the flat pattern should be reduced in proportion to the difference be tween the circumference of standard pipe and the desired circumference of the tubing, by set ting the scale at an angle to the base line suffi cient to reduce the spacings the required amount. In the use of the instrument of my invention, the development or wrap-around template may be drawn on any convenient material. If only a single joint is to be made, it may be drawn on paper, which is subsequently wrapped around the pipe and the outline transferred thereto as by prick punching. If a number of duplicate joints are to be made, the template may be drawn on _1. A layout instrument embodying a polygonal sheetmaterial having a plurality of scales dis posed along the edges thereof, comprising base line projections of equally divided circular arcs corresponding to the inside and outside diame ters of a plurality of standard pipe sizes, to gether with scaies of the developed circumference of similar pipe sizes divided into units corre sponding to the spacings of said circular arcs. 2. An instrument adapted to develop the in tersections of surfaces of revolution, embodying a member having at least one straight edge, a series of coextensive indicia for at least one circle of a desired diameter marked on said straight edge, comprising a scale of Vbase line projections of _uniform divisions of an arc of said circle, and a second scale of the developed lengths of said arcuate divisions. 3. A drafting instrument comprising a plane figure having a plurality of straight edges, and coordinated series of scales marked thereon for a plurality of standard pipe sizes, each set of scales for a >particular pipe size including scales of projections of equal arcuate divisions of cir cles corresponding to the inside and outside di ameters of the particular pipe size, and a scale of the developed length of the arcuate divisions of the outside diameter of said pipe size. 4. A layout instrument comprising a triangle having self-contained means for developing the intersection of surfaces of revolution, said means comprising a plurality of scales of base line pro jections _of a plurality of arcuate curves of vari ous radii divided into equal segments, and cor responding scales of the developed length of such arcuate segments for each radius of said ñrst mentioned scales. . GERALD J. HENJUM.