US2674038A

US2674038A - Roofer's knife

Info

Publication number: US2674038A
Application number: US149227A
Authority: US
Inventors: Donald T Twiss
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-03-13
Filing date: 1950-03-13
Publication date: 1954-04-06
Anticipated expiration: 1971-04-06

Description

April 6, 1954 D. -r. TWISS ROOFER'S KNIFE Filed March 15, 1950 INVENTOR. DONALD T TWISS BY %4%%44 HIS 'A ORNEY a FF? 7 FIIG. 12

FIIG. 13

Patented Apr. 6, 1954 UNI-TED STATES PATENT OFFICE ROOFERS KNIFE Donald T. Twiss, Los Angeles, Calif. Application March 13, 1950, Serial No. 149,227

1 Claim. 1

This invention relates to knives for cutting roofing and particularly to an improved form thereof adapted to supplement the usual hand knives heretofore used and to increase the efficiency and facility with which roofing may be cut to fit the position in which it is applied.

A great number of buildings are roofed with prepared roofing consisting of several plies of paper impregnated and cemented together with various asphalt compounds and generally having an outer surface of gravel or crushed stone. Such roofing is usually sold in rolls and is cut to length and, where necessary, to width to suit the point of use. Heretofore, the conventional hooked point roofing knives have been employed but the gravel and/or stone coated types rapidly dull such knives unless the strip to be cut is inverted and the cutting done from the uncoated side after which the strip is turned back right side up. Also in some cases, the roofing must be cut in place with the strip overlying another strip and in such cases care must be exercised not to cut the underlying roofing.

With the foregoing considerations in mind, it is an object of the invention to provide a roofing knife which may be used to cut gravel or stone coated roofing from the outer face, thereby making unnecessary the heretofore necessary extra work of first inverting the roofing strip and then turning it back.

Another object of the invention is to provide a roofing knife which is adjustable as to depth of cut to accommodate various thicknesses of roofing material.

A further object of the invention is to provide a roofing knife in which the above desirable objects are achieved and which is designed as an attachment for the conventional roofing knife so that the roofer is not burdened with an extra tool.

Still another object of the invention is to provide a roofing knife having a renewable blade of small size so that replacement does not involve the purchase of an entire knife and handle as has heretofore been required.

With the above objects in view together with such additional objects and advantages as may subsequently appear, the invention resides in the parts, and in the construction, combination, and arrangement of parts described, by way of example, in the following specifications of certain modes of execution of the invention, reference being had to the accompanying drawings forming a part of said specification, and in which drawings:

the line 'I1 of Fig. 5,

Fig. 1 is a side elevation of one form of the invention mounted for use on the back of the blade of a conventional roofers knife,

Fig. 2 is an enlarged, top plan view of the form of the invention shown in Fig. 1,

Fig. 3 is an enlarged side elevation of the same side as shown in Fig. 1,

Fig. 4 is a rear elevation of the form shown in the preceding figures,

Fig. 5 is an elevation of the side opposite that shown in Figs. 1 and 3,

Fig. 6 is a vertical, medial, sectional view taken on the line 6-4; of Fig. 4,

Fig. 7 is a transverse, sectional view taken on Fig. 8 is a rear elevation of a second mode of execution of the invention,

Fig. 9 is an elevation of the right hand sideof F g- Fig. 10 is a top plan view of Fig. 8,

Fig. 11 is a top plan view of a third mode of execution of the invention, and

Figs. 12 and 13 are side and rear elevations, respectively, of the third form of the invention.

Referring first to the form of the invention shown in Figs. 1 to 7, inclusive, the knife holding means is formed of two reversely formed L- shaped members I and 2 which are united along a portion of their meeting vertical edges by a built-up weld 3. Above the weld the vertical legs of the members I and 2 are offset from each other to provide a receiving slot 4 for the back of a conventional roofing knife blade 13. Below the slot 4 the meeting faces of the members I and 2 at their mid-width are recessed to form a rectangular slot 5 for the shank 6 of a cutting blade I which projects below the plane of the

horizontal legs

8 and 9 of the members I and 2. The slot 5 may be formed in any suitable manner; as here shown, a hole I0 is first drilled through the united members and opposite sides of the hole are broached to the size and shape of the blade (see Fig. 7). Alternatively, the meeting faces of the members I and 2 may be provided with mating shallow grooves before they are welded together. The shank 6 of the knife is clamped in place by a screw II which passes through a hole I2 in the member 2 and is threaded into the member I as best shown in Figs. 2 and 7.

The offset upper portions of the vertical leg portions of the members I and 2 at their mid width are curved outwardly and thence inwardly to provide reinforcing ribs I3 and I4 and are inclined slightly toward each other (see Fig. 4) to accommodate the taper of the roofing knife blade. The member I is provided with a threaded hole IS in which is located a set screw it which clamps the knife blade B against the face of the member 2 and the hole I5 is so disposed that the set screw engages the opposite side of the knife blade at a right angle. The lower faces of the

horizontal legs

8 and 8 of the members i and 2 are curved (see Figs. 1, 3, 5, and 6) so that the knife may be rocked to a considerable degree without affecting the depth of cut and so that the knife will ride over the rough surface of the roofing. The knife 1 and its shank G are preferably formed of a carbide which is much harder than steel and which, therefore, is not affected by the stone or gravel coating of the roofing. Due

to its small size, the replacement of blades is in-' expensive despite the high cost of the carbide as compared to steel. Also it may be clamped to cut at various depths to suit the thickness of the roofing and as it becomes dulled it can be moved further out of the rectangular slot 5 so that a considerable portion of the knife 'l is available for use.

Preferably, the device is mounted on the back of the knife blade B just at the beginning of the curve leading to the point of the'knife so that when in u e the handle of the roofers knife is inclined upwardly in the direction of out (see Fig. l). The fact that the knife blade 3 is tapered assists materially in holding the device on the knife blade during cutting, and since the blade 1 is disposed directly beneath the blade B, it is easy to follow a line even though the blade 7 is obscured from view.

Referring next to the form of the invention shown in Figs. 8, 9 and 10, the holder If is formed from a steel casting or forging of inverted T- shape as viewed from either end provided with a knife blade receiving slot 18 and an angularly disposed set screw i9 adapted to clamp the holder to a roofers knife blade B in the slot is. Disposed centrally of the holder is a rectangular hole 28 formed in the manner first described in the description of the first form of the invention. Located with capacity for endwise adjustment in the hole 20 is the rectangular shank 21 of a carbide knife 22 of the same type as the knife '5 in the first form of the invention and a set screw 23 threaded into the front edge of the holder engages the shank Zl to clamp it in adjusted position. The laterally extending

arms

2 and 25 on each side of the knife serve to guide it in the same manner as the

members

8 and 9 in the first form of the invention. The use and advantages are the same as the first described form of the invention but the design is better adapted to quantity production.

The form of the invention shown in Figs. 11, 12 and 13 embodies a holder 28 formed from a short length of round steel. On one side face a 4 knife blade receiving slot 21 is provided and offset from this slot and extending through the holder is a rectangular hole 28 in which the shank portion 29 of a carbide blade 30 is disposed. At one side of the slot 21 the holder is provided with a set screw 3| adapted to simultaneously clamp the holder to the blade of a roofers knife and through the engagement of the blade with the shank 29 of the knife 30, to clamp the knife 38 in adjusted position. The mode of use and the advantage achieved thereby are the same as in the preceding forms of the invention, the added advantage being that of simplification in the elimination of one of the setscrews, although the resulting device is somewhat heavier than the preceding forms.

I claim:

A device for cutting mineral coated roofing materials incident to the laying of such materials, said device comprising a knife blade formed of material of sufficient hardness to readily cut roofing material and the mineral coating thereof; said knife blade having a rectangular shank, and a holder therefor in which said shank is mounted; said holder comprising a body having a slot extending across one end thereof for reception of the back of a blade of a roofers knife and being provided with setscrew mean extending from the exterior of said body through a side wall of said slot operable to clamp the roofers knife blade against the opposite side Wall of said slot, a rectangular opening extending through said body member from the bottom of said slot and emerging at the end of said body member opposite said slotted end thereof; said rectangular shank of said knife blade being disposed in said rectangular opening with the cutting edg thereof disposed beyond said opposite end of said body member, and other setscrew means carried by said body member extending from the exterior thereof into said rectangular opening operable to clamp said rectangular shank therein in adjusted position longitudinally of said opening; said body member at said opposite end thereof having roofing surface contacting flange portion extending laterally in a common plane from both sides of said knife shank and being effective to determine the depth of cut made by said knife blade incl: dent to the adjusted position thereof in said rectangular opening.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 538,459 McCausland Apr. 30, 1895 718,882 Savaria Jan. 20, 1903 1,129,310 Platt Feb. 23, 1915 1,940,270 Rainwater Dec. 19, 1933 2,282,729 Knauf May 12, 1942. 2,579,773 Williams Dec. 25, 1951