US944799A - Pitch-board. - Google Patents

Description

O. E. LYTLE.

PITCH BOARD.

APPLICATION :IILED MAR. 16, 1908.

944,799. Patented Dec. 28, 1909.

3 SHEETS-SHEET 1.

CHARLES EDWIN LYTLE, OF ST. JOSEPH, MISSOURI. I

Biron-Benin).

names.

Specification of Letters Patent. Patented Dec. 28, 1909.

Application filed March 1c, 1908. Serial in. 421,320.

To all whom it may concern:

Be it known that I, CHARLES EDWIN LY'rLn, a citizen of the United States, and a resident of St. Joseph, in the county of Buchanan and State of Missouri, have invented a new and Im roved Pitch-Board, of

' which the following 1s a full, clear, and exact description.

The invention relates to measuring instruments, and its object is to provide a new and improved pitch board, more especially designed for use by carpenters, to enable them to readily and accurately obtain the length and bevels of rafters, thus enabling a carpenter to frame the roof of a building with ease and despatch and without the use of a square or a bevel and without requiring mental calculations.

The invention consists of novel features and parts and combinations of the same, which will be more fully described hereinafter and then pointed out in the claims.

A practical embodiment of the invention is represented in the accompanying drawings forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figures 1 and 2 are face views of opposite sides of the instrument; Fig. 3 is a horizontal sectional View of ,the sameon the line 3-3 of Fig. 2'; Fig. 4 is an enlarged front viewfof the im irovement; Figs. 5 and 6 are face views 0 opposite sides of the swing arm, and Fig. 7 is a transverse section of the improvement on the line 7-7 of Fig. 1.

The plate Aof the pitch board is preferably made of sheet metal, and is rovided with the side edges A, A standing at a right angle one to the other, and near the a ex of the said sides A, A is arranged a pivot B for an arm G to swing on, the said arm being slotted toprovide front and rear members C, C extending on opposite faces of the plate A, as plainly indicated in Figs. 3 and 7. The front and rear members O, C are engaged near their outer ends by a clamping bolt D, to clamp the saidmembers upon the plate A, thus holding the arm C in position on the plate A after the desired ad ustment is made, as hereinafter more fully described. On the outer or free end of the swing armC is arranged a tablet E of slate or other suitable material, to permitthe user of the instrument to write memoranda thereon, such as the length of the rafters and other desiderata. j

On the front face of the plate A (see Figs. 1 and 4) is arranged a segmental graduation F, indicating one-half of the widthsof buildings, and next to this graduation F are arranged'sets of segmental concentric graduations G, G, of which the graduation Gr indicates the length in feet of main or common rafters,,while the graduation G indicates the length in feet of hi rafters. The segmental .graduations F, (g and G have their center coinciding with the center of the pivot B. a

On the front member O of the swing arm (1 is formed an elongated opening C covered vby a pane H Fig. 7 of transparent material such as glass, celluloid and the like, andthrough which ane the graduations F, G and G are visi 1e. On the pane H are en raved or otherwise produced versub-divisions, the foot corresponding to one foot as represented on the corresponding graduations G, G.

On the member O at the outer end of the opening O is produced the legend Width of buildin indicating that the gradua tions F an I are for indicating one-half of the width of a building in feet and subdivisions thereof. On the member C to the left of the opening C is produced in the direction of the length of the arm O, the word rafters and transversely thereto the Words main and hip. Opposite the graduations J, J and on the member O are produced the fractions 4, and each fraction being complementary to the pairs of graduations G, J and G, J. Adjacent to the fractions is produced the word pitches, indicating that the fractions are pitches of the roofof a building.

In using the device for obtaining the length of the main rafters or hip rafters, the user of the instrument-proceeds as follows: If the building to be erected issay 23 feet 4 inches wide, then one-ha f this width is 11 feet 8 inches, and this length is indicated by swinging the arm O on the plate A until 11 feet 8 1nches are indicated by the graduations I and F, as illustrated in Fig. 4. Now if the roof is to be one-third pitch then the operator reads the length of the main rafter on the graduations G, J at A; pitch, and will thus find that the length of the main rafter is to be 14 feet and the length of the hip rafter can be read at the graduations G, J for A; .pitch as 18 feet 2 inches. Thus from the foregoing it will be seen that the length of the main or common rafters and hip rafters for the different widths of buildings can be readily read ofl,

sition on the plate A and fastening it therei on by the. clamping bolt D.

in outthe cuts for the top ends of hi For obtaining the length of jack rafters, the distance from the corner of the building to the location of the jack rafter is laid out by the use of the swing arm O on the graduations F and I.

In order to obtain cuts for main rafters and hip rafters on the various pitches, the following arrangement is made: On .the front face of the late A below the innermost raduation are arranged the segmenta raduations K, K, representing pitches fir hip rafters and main rafters, and on the lower end of the pane H is arranged a radial hair line L for setting the arm C on the corresponding pitch graduation K or K, the angle between the sides of the arm C and the edges A and A giving the corresponding plumb and level cuts.

On the right hand side of the plate A are formed a series of V-shaped slots N for layd:

an va ley rafters for the different pitches marked in the angle of the said slots, as shown in Fig. 1.

In using the V-sha ed slots, one of the slots is placed paralle with the side of the rafter, the other being transverse to the rafter and markin the line of the cut.

On the left-ban side of the plate A are arranged a series of straight slots 0 at angles to the edge A, to lay out the bevel cuts on. the upper ends of jack rafters for the various pitches marked on the plate- A at 'the correspondin slots.

In using the a ove slots, the central line of the plate which is designated by the line Rin Fig. 2 is laid paralle the rafter, and the slots O designate'theline 'of the on min using the apertures -Along the outer marginal edge of the plate A are formed apertures P, to permit the user to mark the foot or base of a. rafter at the point of prpljection of the rafter over the side of the u ding.

I the central line of the plate whichis designated by the line.

It is placed at right angles to the rafter, a\t

with the edge of the point of the rafter which is even with the edge of the building, and a pencil is inserted through the proper opening P, to mark the point on the rafter where it is to be out, the distance between the pencil mark and the central line R is the distance which the rafter end projects beyond the building.

On the reverse faceof the plate A (see Fig. 2) is arranged a protractor scale Q, on which indicates a radialhair line R, engraved or otherwise produced on the pane H of transparent material and covering an openin (3* formed in the rear clamping member 2 of. the arm C. The scale is marked in both directions, so that by the arrangement described the arm O can be readily set at any desired angle relative to either side A or A of the plate A.

Miter lines S and S for octagons and hexagons appear radially on the plate A above the scale Q, to allow of setting the arm C by the hair line R on the miter lines and relative to the edge A of the plate, to obtain the sides of octagons and =hexagons.

The hair line B is also adapted to indicate on graduations T,-T indicatin pitches for plancher bevels and lancher ace cuts,

it being understood that 1n order to obtain a plancher bevel or a plancher face cut the arm C is swung until the hair line B coincides or T, and then the arm C is 'fastenedin place and the corresponding bevel or face out can be laid by the u e of the arm O and the edge A of the plat A.

Havlng thus described my invention, .1

claim as new and desire to secure by Letters ing adjacent sides standing at a right angle to each other, an arm mounted to swing on the said plate and rovided with ahair line, and segmental gra nations on the'said plate, indicatin the itch for the main and hip rafters, t e sai graduationathe said hair line and the said adjacent sides determining plumb and level cuts for rafters."

3. A device of the class described, comprising a plate of sheet material provided other, an .arm slotted to receive the plate and with two side edges at right angles to each pivoted thereto near the junction of the two sides,'means for clamping the 'arm'on the plate, said plate being provided with a plu- 95 with the desired pitch on the graduation T rality of are shaped scales, said plate having 7 adjacent to one of said side edges a series of and pivoted thereto near the junction of the two sides, means for clamping the arm on the plate, said plate being provided with a plurality of are shaped scales, said plate having adjacent to one of the said sides a plurality of slots at different angles tothe said sides for the purpose set forth.

5. A device of the class described comprising a plate of sheet naterial provided with two side edges at right angles to each other, an arm slotted to recelve the plate and pivoted theretonear the junction of the two sides, means for clamping the arm on the plate, said plate being provided with a plurality of are shaped scales, said plate having spaced apertures adjacent to one of said side edges for the purpose setf forth. In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES EDWIN LYTLE. Witnesses:

J. C. HEDENBERG, A. GWYNNE-VAUGHAN.

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