US1333912A - Apparatus for cutting helical propellers - Google Patents

Description

C. H. GRANT. APPARATUS FOR CUTTING HELICAL PROPELLERS.

APPLICATION FILED NOV-22, 1919.

1,333,912. Patented Mar. 16, 1920.

2 SHEETS-SHEET l.

C. H. GRANT.

APPARATUS FOR CUTTING HELICAL PROPELLERS.

APPLICAHON FILED NOV. 22, 1919.

( Patented Mai. 16, 1920.

2 SHEETS-SHEET 2- ['1' III-,

CHARLES HAMPSOTI GRANT, OF NEVT YOR K, N. Y.

APPARATUS FOR. CUTTING HELICAL PROPELLERS.

Specification of Letters Patent.

Patented Mar. 16, 1920.

Application filed November 22, 1919. Serial No. 340,022.

To all whom it may concern Be it known that I, CHARLES HAMPsoN GRANT, a citizenof the United States, residing in the city, county, and State of New York, have invented certain new and useful Improvements in Apparatus for Cutting Helical Propellers, of which the following is a specification.

This invention relates to improved means for cutting helical bladed propellers of the type used in airplanes;

The principal objects of the invention are to simplify the operations and to reduce the cost of manufacturing propellers by providing apparatus for mechanically cutting helical blades on rough propeller blanks.

The invention consists in certain features of construction, arrangement, and combination of parts, hereinafter described and particularly pointed out in the claims.

the accompanying drawings, il1ustrating my invention,

Figure 1, is a top view of 'a jig used for holding the propeller blank in cutting the back or convex face of the blade;

7 F ig. 2, is a side view thereof;

Fig. 3, is a fragmentary perspective view of a shaper showing the knives employed in forming the back of the blades;

Fig. 4: is aside view of one of the knives used in cutting the front of the blade;

Fig. 5, is a -t0p view of the jig used in forming the front or concave face of the blade;

Fig. 6, is a side view of the same;

Fig. 7, is a vertical section on the line 7-7 I of Fig. 6; and

Fig. 8, is a perspective view 'of the propeller blank. I

- The apparatus employed in carrying out my invention consists, generally, of an ordinary shaper provided with removable cutting knives, a jig for holding the blank in cutting the back of the blades, and a second jig for holding the blank in cutting the *front of the blades.

In the manufacture of the propeller, I- take a blank A having the general outline of a double-bladed propeller, such as is the blades after which the blank is turned endwise in the jig and the back of the other blade is out. After the back of the blades have been formed, the blank is removed from said and placed in the second jig with the back of the'blades downward, and then the front faces of the two blades are successively cut.

The rotary shaper employed in cutting the blades may be of any ordinary or approved construction. As illustrated in the drawings it consists of a revolving vertical shaft 1 projecting through an opening in the worlctable 2 and provided with a fixed collar 3 and a removable collar 4 between which the cutting knives 5 are held. The collars are formed with grooves into which the knives fit and a nut 7 is provided for clamping the collars together so as to tightly hold the knives in position.

It is essential that the knives be formed with parabolic cutting edges. The knives shown in Fig. 3, are provided with con cave parabolic-shaped cutting edges 6' and are used in forming the back or convex face of the blades, while the knives 5", 'one of which is shown in Fig. 4, are formed with convex parabolic shaped cutting edges 6' and are used in cutting the front or concave face of the blades;

My improvement relates particularly to the jigs in which the propeller blank is held while the faces of the blades are being cut by the parabolic-shaped knives revolving at highspeed. Referring now to Figs. 1 and 2, the jig used in making thefirst cut consists of a base 8, a plate 9 adjustably mounted on the base, and an inclined blocklO carried on the plate. The block 10 preferably has its lower end hinged at 11 to the plate 9 and has its upper end supported in graduated arms 12 so that the angle of inclination of the block may be adjusted to permit of varying the pitch of the blades. .A cavity13, substantially similar in outline and depth to the blank A, is formed in the inclined face of the block to receive and hold said blank. A portion of one side of the block 10 is cut away as indicated at 14 so as to expose an end of the blank and to allow the shaper knives to come into cuttin contact therewith. It will be m'lde'rstoo" that incutting in arms 12.

the blades the position of the rotary sha per is stationary and that the jig is moved on the surface of the work table thereof.

The front ed e of the is formed with a cam-shaped recess 15 of such configuration that when the jig is pressed against the collar 3 of the shaper, the lower or hub portion of the exposed end of the blank will contact with the heel or lower portion of the cutting edges 6 of the knives 5, and

that as the jig is moved endwise, in the direction of the arrow in Fig. 1, the line of cutting contact will gradually travel from the heel toward the point of the knives, thus producing the desired helical shape of the back of the'blade.

An arm 16, pivoted at 17, is provided to hold one end of the blank firmly in place in the jig while the other end is being out and to prevent the blank from chattering during the cutting operation. The arm is locked in its holding positlon by means of .9, and an. inclined block 10 having its lower end hinged at 11 to the plate 9 and having its upper end adjustablysupported The block 10 of this jig is inclined in the opposite direction of the block 10 of the jig heretofore described. The jig is provided with a cavity 13 for receiving the blank, the bottom of which cavity is shaped to correspond with the back of the blades, as seen in Fig. 7. A portion of the block 10 18 cut away as at 14: to allow the knives 5 to come into contact with the end of the blank, which is to be out.

In cutting the front face of the blades the knives 5 of the shaper are replaced by the knives 5, one of which is shown in Fig. 41-, which knives have convex parabolic cutting edges 6. The cam-shaped recess 15' of the jig is so designed that when the jig is pressed against the collar 3 and is moved in the direction of the arrow in Fig. 5, the line of cuttingcontact of the knives 5 will travel from the point to the heel and will thereb cut the front face of the blade in the desired helical shape. nn arm 16 pivoted at 17 and adapted to be locked by the lever 18 is provided to firmly hold one end of the blank in the jig while the other end is being out.

When the front face of one "blade has bee-n of the shaper 2. In apparatus for cutting helical propeller blades, the combination with a rotary shaper,. of a jig for holding a propeller blank with an end portion exposed and ar ranged that when the jig is moved in operative relation to the shaper the knives of the latter will out the surface of the exposed end portion of the blank to form one face of the blade.

3. In apparatus for cutting helical propeller blades, the combinationwith a rotary shaper having parabolic shaped knives, of a jig for holdinga propeller blank in an inclined position with one blade exposed, said jig being constructed that when 'it is moved in operative relation to the shaper the knives will engage the exposed blade at its hub and will cut the blade from the hub outward.

4:. In apparatus for cutting helical pro peller blades, the combination with a rotary shaper having a collar and provided with knives formed with parabolic shapedcutting edges, of a jig for holding a propeller blank in an inclined position with one blade exposed to the action of the knives, said jig having a recessed portion serving as a guide, when the jig is moved with its recessed portion pressing against the collar of the shaper, to cause the knives to out the exposed face of the blade in'helical shape.

5. In apparatus for cutting helical propeller blades, a jig comprising an inclined supporting member provided with a seat for a propeller blank and having a portion cutaway to expose an end of the blank, and a base member formed with an irregular shaped recess disposed substantially in line with the cut-away portion of the supporting member. 7

6. In apparatus for cutting helical pr0- .peller blades, a jig comprising an inclined supporting member provided with a seat for a propeller blank and having a portion cut-away to expose an end of the blank, means mounted on said memberfor firmly holding. the blank inrits seat, and a base memberformed with an irregular shaped recess disposed substantiallyin line with the cut-away, portion of the supporting member. 7 I

'7. In apparatus for cutting helical propeller blades, a jig comprising an adjustably inclined supporting block formed with a seat I for receiving a propeller blank and having a portion of the block cut-away to expose one end of the blank, a member pivoted on the block and engaging the other end of the blank to firmly hold it in its seat, and a base member formed with an irregular shaped recess disposed substantially in line with the 10 cut-away portion of the block.

8. In apparatus for cutting helical propeller blades, a jig comprising a base having an irregular shaped recess, a plate ad]ustably mounted on the base, and an inclined 15

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