US1236486A - Rafter-miter. - Google Patents

Description

A'. L. RUTQUIST.

RAFTER MITER.

APPLICATION FILED OCT. I8, 1916.

. Patented Au 'rnvrn errate .armar einen. i

AXEL L. RUTQUIST, OF WALLACE, IDAHO.

BAFTER-MITER.

Application filed October 18, 1916.

To all whom t may concern.'

Be it known that I, AXEL L. RUTQUIST, a citizen of the United States, residing at l/Vallace, in the county of Shoshone and vState of Idaho, have invented certain new and useful Improvements in Rafter-Miters, of which the following is a specification.

My invention relates to improvements in rafter miters, and the object of my invention is the provision of a device of this character especially designed to enable a workman to quickly, accurately, and automatically determine the angles of various correlated rafter cuts, without having to resort to the old cut and try method, or to the use of difficult and time consuming mathematical calculations.

It is well known that the work of laying out of rafters in the usual way by the use of an ordinary square for securing the desired rise and run or the proper lines for the ridge and plate cuts, requires considerable skill, mathematical knowledge, and great care in order to avoid serious errors. I/Vith my device it is Vpossible for a carpenter of ordinary intelligence to readily ascertain the angles of the desired cuts with absolute unerring accuracy.

Broadly, I provide an instrument which is capable of various adjustments in planes angnlarly related to a stock, the adjustable elements comprisingI a plurality of straightedges or arms pivotally and slidably mounted in said stock and so connected and coordinated that the movement and adjustment of one arm will serve to automatically adjust the remaining angle members so as to indicate `the proper cuts for the several types of rafters.

The use of my invention will be hereinafter fully explained, and the construction of one form or embodiment thereof specilically described, recourse being had to the accompanying drawings, in which- Figure 1 is a longitudinal side elevation of the device as it appears with the angle or miter arms incased inoperatively within the stock.

Fig. 2 is a longitudinal sectional view of the stock taken on line 2 2 of Fig. 3., and

.showing the straight-edges withdrawn from the stock and set for a half or 45 degree angle where the pitch begins, the dash-lines indicating the arms positioned for a cut of diferent angle.

Specification of Letters Patent.

Fat-elated Aug. 14, 1917.

Serial No. 126,404.

Fig. 3 is a somewhat enlarged transverse sectional view on line 3--3 of Fig. 1, and

Fig. 4 is a` greatly enlarged fragmentary transverse sectional view of Fig. 1. t Referring more particularly to said drawings, in which like reference characters indicate like parts in the several views, the numeral l designates the stock of my instrument which is preferably of metal and in the form of an elongated casing having a pocket 2 extending interiorly throughout its dimensions, the side-walls 8 and 4 of the casing being extended to provide the longitudinal oppositely disposed flanges 5 and 6. A plate 7 is fitted in the pocket 2 and fixedly secured in place to the side-wall 4 by means of rivets or screws 8. rlhis wall 4 and plate 7 are provided with corresponding and registering diagonal slots 9, and the curved elongated slots 10, while the plate 7 also has a curved hook-shaped guideway or slot 11 anda lguideway or slot 12.

As clearly illustrated in Figs. 1 and 2, the straight-edges or angle- arms 9, 10, 1l and 12 are pivotally mounted at their inner ends in their respective slots 9, 10, 11, and 12. Their opposite ends are pivotally mounted in close adjacent relation, to a bar 13.

For the purpose of locking the straightedges in any desired adjusted position I provide the internally threaded pivotal member 9 with a threaded and headed lockingI bolt or setscrew 14, the inner end of the bolt extending through the side-wall 3 of the casing, as clearly shown in Fig. 4, while the arm 10 has a similar locking device indicated at l0.

rIhe illustration, Fig. 2, shows the instrument set where the pitch begins or at an angle of 45 degrees for the arm 12', while the dotted lines indicate a diiferent lesser angle of adjustment of the straightedges, showing the true positions of the several arms for indicating the proper angles upon the rafters for making cuts for the joints.

In ascertaining the true angles for the cuts of the several rafters subordinate to the angle or pitch of the common rafters, the two set screws are first loosened to allow the straight-edges to be pulled out of the casing. The plumb cut for the common rafters having been determined with a steel square, a line is drawn en the rafter te in dicate the same. Then the angle-arm which represents the angle of plumtb cut for the common rafter is placed parallel with this line and the locking screws tightened. The angles of the cuts for the several rafters Will be accurately indicated by the arms, as follows: arm 11 for the plumb cut of hip or valley rafters; arm 9 for the plumb cut of the common and jack rafters; arm 10 for the side cut of the hip or valley rafters; and arm 12 for the side cut of the jack rafters. v

In every instance, the angles indicated by the arms represent the same purpose for any adjusted pitch. When once set there can be no mistakes as the cuts are ascertained mechanically with absolute accuracy, it being understood that the adjustment of the master arm 9 from its pivotal point X governs the adjustments of the several angle members automatically, as their movements are controlled by the curves of the slots in which they are respectively pivoted.

The curves for the slots are plotted by first establishing the correct or true angles which the legs will assume under given conditions. The plumb eut of the common rafter edge constitutes the base from which the other cuts are gaged, and hence the other edges must be adjusted to conform or correspond With the correlated cuts for a given pitch orpredetermined angle of the common rafter plumb cut.

To secure these curves the master arm or edge 9 is rst set at 90 degrees to the straight edge of the stock and the correlated angles of the arms 10', ll, and 12 having been determined for that particular angle the arms are set at such angles and dots made on the pattern piece for the stock to indicate the initial connecting points of the stock ends of the arms as clearly shown in solid lines in Fig. 2 of the drawings. The master arm or edge 9 is then set at an angle to give a slight degree of pitch, say 85 or 87 degrees to the stock. The angles of said correlated arms or edges Which, as heretofore explained, are intended to designate for all establishedI pitches of the master arm, the side cuts oft jack rafters, the side cuts of hip and valley rafters, and the plumb cuts of hip and val?- ley rafters, are then computed, the posi-` tions of the arms set to the correct angles'@- and dots used toindicate on the stock pat-l`l` tern piece the guide or stock connecting'`v The foret, going operation is repeated successively, theiii points for the respective arms.

master arm being shifted by degrees, the correlated angles determined, and the dots used as before. All the desired angles having been thus ascertained and plotted, lines arethen drawn connecting the dots for the respective arms, the curve for each slot Vbeing indicated by the lines. In the foregoing explanation it is to be understood that the references to the master arm and the correlated arms are used figuratively, the actual plotting being` made upon the usual pattern sheet, the several arms being ofV a desirable or convenient length and the dimensions of the stock being such as Vto accommodate the scope of the slots.

From the foregoing description taken in connection With the drawings, it is apparent that I have provided a meritorious instrument of novel and advantageous construction, Well adapted to fulfil the purpose for which it Was designed.

Having described my invention, I claim 1. An instrument of the character described, consisting of a stock member provided with a plurality of curvilinear correlated slots or guideyvays, an angle-arm piv otally mounted in each of said slots or guideways, and a master angle-arm pivotally mounted in said stock member, the outer ends of said arms being pivotallyrretained in adjacent relation.

2. An instrument of the character described, consisting of a stock member provided with a plurality of curvilinear correlated slots or guideWays, an angle-arm pivotally mounted in each of said slots or guideways, a master angle-arm pivotally mounted in said stock member, the free ends of said arms being adjustably retained in adjacent relation, and locking means. for securing said arms in adjusted position relative to said stock member. v

3. An instrument of the character described, consisting of a stock member hav ing a straight edge and provided with a plurality of curvilinear correlated slots or guidevvays, an adjustable angle arm slidably mounted in each of said slots or guidevvays, and an adjustable master angle arm pivotally connected to said stock member, the adjustment of the rst mentioned arms being mechanically and automatically controlled by adjustable movement of the l master arm.

In testimony Vwhereof I hereby afX my signature.

AXEL L. RUTQUIST.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents. Washington, D. C.

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