US2094204A - Method of and apparatus for manufacturing rolled steel worms - Google Patents

Description

p H. c. CARTER ET AL 2,094,204

METHOD OF AND APPARATUS'.FOR MANUFACTURING ROLLED STEEL WORMS.

' Filed March 7, less 4 Sheets-Sheet 1 Sept; 1937- v H. c. CARTER ET AL ,METHOD OF AND APPARATUS FOR MANUFACTURING ROLLED STEEL WORMS 4 Sheets-Sheet 2 Filed March 7, 1956 III! II!!! II!!! III! I II!!! H.C.CARTER E A-LYVQLLACE 47-7-U WE Sept; 28, 1937. c, CARTER r 2,094,204 METHOD OF AND APPARATUS FORMANUFACTURING ROLLED swam, womns Fild. Match 7, 1936 4 Sheets-Sheet 3 3O 2O lllmluullnllnnlm m/z/w TURS HCCAETEIR 5 A'L-WALLACE' /7 frua/vss Sept. 28, 1937. H. c. CARTER El AL 2,094,204

' METHOD OF AND APPARATUS FOR MANUFACTURING ROLLED STEEL WORMS Filed March '7, 1956 4 Sheets-Sheet 4 HL. CARTER A.L.WALLACE worms.

Patented Sept; 28, 1937 METHOD OF AND APPARATUS FOR MANU- FACTURING ROLLED STEEL WORMS Haskell C. Carter and Albert L. Wallace, Portland, Oreg., assignors to Iron Fireman Manufacturing Company, Portland, Oreg.

Application March 7, 1936, Serial No. 67,696

4 Claims. (Cl. 153-645) This invention relates generally to the manufacture of conveyor worms such as are used in coal burning stokers and particularly to a method of and apparatus for manufacturing rolled steel The main object of this invention is the evolution of a process and the productionof an apparatus for manufacturing worms from rolled steel and to produce these worms in dimensions hitherto regarded as practical only by the use of a casting process.

The second object of this invention is the development of a method of and apparatus for manufacturing conveyor worms of cold rolled steel for the purpose of changing a straight bar to a. helix and to avoid the necessity of applying heat during its forming operation which would detract from its finish and to do so at a material saving in cost.

The third object-of this invention is the development of an apparatus and method whereby full depth flights may be successfully and accurately wound upon a supporting arbor or core.

The fourth object is the development of an' apparatus whereby a continuous flight can be wound upon a core or arbor in a manner that it will be formed to the desired pitch by imparting to the bar as it is wound upon the arbor a controllable holding action whereby a twisting action may be imparted to the bar in either direction and also the angle at which the bar mounts the arbor can be varied with relation to the helix angle.

The fifth object is the provision of a means 35 for accurately guiding a worm flight upon an arbor in a manner to overcome any tendency for the flight to lie over on its side during the coiling operation.

The sixth object is to so construct the appara- 'tus that it can successfully form the worms although the relations between the depth and thickness of the flight, the helix angle, the diameter of the core, and the character of the steel may vary through a relatively large range;

45 We accomplish these and other objects in the manner set forth in the following specificationas illustrated in the accompanying drawings, in which:

Fig. 1 is a perspective view of the worm forming machine.

Fig. 2 is a section taken along the line 2--2 in Fig. 1. e

Fig. 3 is a section taken along the line 3-3 in Fig. 6.

Fig. 4 is a transverse section through a bar from which the flight is formed prior to the' winding operation.

Fig. 5 is a view similar to Fig. 4 but showing the cross section of the flight after the winding operation. 5

Fig. 6 is a section taken along the line 6-6 in Fig. 3.

Fig. '7 is a section taken along the line in Fig. 6.

Fig. 8 is a section taken along the line 8-8 in Fig. 6.

Fig. 9 is a plan showing a modified form of the device by means of which the worms can be formed in an ordinary winding machine constructed after the fashion of an engine lathe.

Fig. 10 is a section taken along the line Ill-J0 in Fig. 9.

Fig. 11 is a section taken along the line li -ll in Fig. 9.

Fig. 12 is a fragmentary elevation showing the graduated scale on the adjustment for the bar holding mechanism.

Fig. 13 is a section taken along the line 13-43 in Fig. 10.

. Fig. 14 is a section taken along the line -14 2 in Fig. 9, showing the bar being twisted to the left of a plane which is normal to the conveyor ax1s.

Fig. 15 is similar to Fig. 14, but showing the bar being twisted to the right of the plane which is normal to the conveyor axis.

Fig. .16 is a fragmentary plan of a section of the worm at its winding point showing a twisting motion being imparted to the bar as shown in Fig. 15.

Fig. 17 is a view similar to Fig. 16 but showing a twist being imparted in the direction shown in Fig. 14.

Fig. 18 is a fragmentary plan of a worm at its winding point showing the bar being held to the left of the helix angle. i

Fig. 19 is similar to Fig. 18 but showing the bar being held to the right of the helix angle.

Similar numbers of reference refer to similar parts throughout the several views.

Before entering into a detailed explanation of this invention, it must be understood that the a success of the apparatus herein described as well as the method of winding the worms is dependent largely upon the, ability to easily and accurately control the helical and radial angles of the bar as it mounts the-worm.

It must also be understood that numerous methods ha e been employed in the formation of lglltd. Steel worms, the commonest method being that of rolling a straight bar in a manner to elongate one side thereof, and thereby convert same into a helix. A typical example of this is illustrated in Patent No. 368,569.

Others have formed circular perforated discs which are split and the split ends of eachsection joined to the split ends of adjacent sections, after which the united sections would be stretched to the desired pitch. This type is illustrated in Patent No. 1 738,994.

The third and very common form of conveyor flight is known as the sectional type illustrated in Patent No. 643,636.

A fourth type is illustrated in the patent of Green, Patent No. 361,998, in which a bar A is closely wound upon an arbor on edge and then stretched to the desired pitch. In this patent, the bar from which the helix is made is actually wound upon the arbor and is prevented from lying over on its side by closely winding the helix. This is objectionable in that it sets up a stress in the metal during the flnal stretching operation necessary to obtain the desired helix angle,.arid that in a worm so formed it is difllcult to maintain a true pitch along the length of the worm.

In spite of the fact that car springs have long been made by winding flat bars on edge into helical form, and it would seem to be a short step from the formation of a car spring to the insertion of an arbor therethrough for the purpose of forming a worm, there has been until the present time a relatively sharp limitation to the size of .the worm, the radial depth of its flights, the relative thickness thereof, and the character of the steel employed therein.

With the method which we are about to describe and the apparatus which we employ therein, the objections to the known methods as illustrated in the foregoing statements are overcome, and we are able to easily produce a smooth and accurately woundworm with a minimum of internal stresses and having its flight tapering in thickness with the thin edge outermost.

In the form of the device shown in Figs. 1 to 8 inclusive, there is shown a bed 20 which includes the guides 2i. At one end of the bed 25 is disposed a head 22 which is in the form of a housing containing the gears 23 and 24 which are con- .nected by means of an interposed idler 25. At the other end of the bed 26 is mounted the tail stock 25 in which journals the arbor or core 21 of the worm to be formed. The arbor 21 is secured to the gear 24.

Journaling in the end 23 of the bed 25 is a revolvable splined shaft 29 which is keyed to the gear 23.

On the guides 21 is mounted a carriage 35 through which slidably extends and in which Journals the arbor 21 and the shaft 29. The carriage 33 is provided with the transverse walls 3|, 32, and 33. In the walls 32 and 33 is mounted a die 34 in which is formed a helical slot 35 which extends from the exterior 35 to the interior 31 within which journals the worm 34 is held against rotation by means of the here 33. g

The wall 32 is provided with a slot 33 which is tangent to the slot 35 in the die 34. It is desirable to provide a roller 45 in the slot 35 on. the side thereof against which the bar-'4 l bears in its passage through. the slot 33. v

Extending through the wall 31' and into the die .34 is a tubular sleeve 42 whose flanged end 43 is secured to the wall 31 by means of the screws 44. On the sleeve 42 is mounted a gear 45 which is 5 integral with the pinion 40.

core 21. The die Disposed around the. axis of the die 34 are the four rollers 41, each of which has its reduced end 48 joumaling in the eccentric bushing 49 in the walls 32 and 33. Meshing withthe pinion 45 are the roller drive gears 50 which are secured on the reduced ends 48 of the respective rollers 41.

Journaling in the walls 3| and 32 is a shaft 51 on which is secured a pinion 52 which meshes with and drives the gear 45. Alsosecured to the shaft 5| is a gear 53 which meshes with the pinion 54 of the drive motor 55.

Journaling in the wall 32 is a cylindrical nut 56. On the nut '56 is formed a gear 51 which is driven through an idler gear 58 from the gear 45. The gear 51 is held between the walls 3| and 32 and prevents the longitudinal movement of the nut 56 with relation to the carriage 30. Secured to the bed 2|! is a stationary screw 59 which passes through the nut 56.

V The operation of this form of the device is as follows:

A section of worm flight 60 is permitted to remain within the die 34 at all times, and the flight portion is made continuous by merely welding the bars end to end. Assuming that the worm core 21 is in place and that the carriage is adjacent to the head 22 and that a section of the worm flight 60 has been secured to the core '21 at the end 6|, the-operation of the motor 55 causes the rollers 41 to be rotated and thereby cause a driving action to be imparted to the worm flight 65 and also to cause the core 21 to be rotated through the driving action of the shaft 29 and in addition thereto to cause the carriage to be moved along the bed 20 at a speed which would be equal to that at which it would be driven if the worm flight 50 itself provided the propelling action for the carriage 30.

As the worm flight is formed, it is secured upon the arbor 21 by means of a welding operation, and there is indicated a welding rod 62 which is held at the junction of the worm flight 65 and the core 21 by means of the holder 53. The flight 65 may be propelled through the die 34 by the separate or joint action of the rollers 41 or the turning movement supplied by the gear 24.

The worm thus formed is very correct as to pitch along its entire flight and flts smoothly upon thecore 21 and is in perfect axial alignment throughout so that the vcore itself is not needed to hold the worm to a true axis.

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The mechanism thus far described is a somewhat general description of the machine employedin our process; but the details of construction which contribute most to the success of the method are illustrated in Figs. 6 and 9 to 19 inclusive. Fig. 6 shows the means for positively holding the flight to a true helix during the winding operation while Figs. 9 to 19 inclusive illustrate the means for accurately guiding a night as it mounts the arbor in a manner to overcome any tendency for the flight to lie over on its side.

It will be noted that in Figs. 4 and 5 are shown cross sectional views of the worm flight before and after the winding operation in which the completed flight is of reduced thickness at its outer edge and increased thickness at its inner edge, which is the one bearing upon the core 21.

Refening now to the second form of themvention, there is shown a lathe chuck 54 by meansof which is held the core 21 which is supported in a guide bushing 35 which is mounted on the lathe carriage 33 to which movement is imparted by means of a lead screw 61 through the change gear 68 such as are in common use.

Mounted on the carriage 66 is a head 59 which is mounted on the vertical pivot 10. To the piv- 0t Ill is secured a worm wheel II which meshes with a worm 12 which is capable of being rotated manually by means of the hand wheel H3. The worm I2 is connected to the handwheel "it by means of a shaft 14 which journals in the carriage 56. The head 69 can be clamped in any desired position by means of the bolts iii which occupy the arcuate slot 16 in the head 59, making it possible-to clamp the head t9 rigidly to the carriage St. The head 69 is provided with a cylindrical opening ii in which is placed a cylindrical slotted guide it, which is adapted to receive the bar M. The head he is provided with a slot 79 across which extends the bolts Bil. The guide it is provided with a space key iii which prevents the tightening of the bolts 80 from closing the slot 82 in the guide I8.

Rotary adjustment of the guide it is accomplished by means of a worm wheel 83 which meshes with a worm 84 which in turn may be manually rotated by means of a hand wheel 85.

Obviously, the wheel 85 may not be turned unless the bolts 80 are first released.

It is desirable to provide graduations 81 on the face 88 and an indicator point 89 on the carriage 66 for the purpose of facilitating the making of settings. Corresponding graduations 90 should be provided for the guide 18 with relation to the head 69. A clamping screw M is also provided for the worm wheel 83 which bears the graduations 90 and which is attached directly to the guide .18. 1

It will be noted that in Figs. 14 to 1'7 inclusive are shown conditions in which the bar ii is caused to mount the arbor 21 in a manner which is not radial with the axis of the core 21 but inclined to the right or left of the axial plane at the point where the guiding takes place, namely, while the bar 4| is within the guide 18. The

purpose of this is to offset the tendency possessed by the particular specimen of bar 4| to lie over on its side while being wound. However, the

ability to twist the bar radially for the purpose of overcoming this tendency is not suificient in most cases and it is commonly found necessary to accurately adjust the helical angle at which the bar 4| passes through the guide I8. Two examples of such adjustments are shown in Figs. 18 and 19 in which the straight portion of the bar 4| is held to the left and right of the helicalangle 55 93 as indicated in dotted lines in these figures.

In the form of the device illustrated in Figs. 9 to 19 inclusive, the force. necessary to wind the worm flight 60 is imparted by the chuck 64 directly tothe core 21 itself and to the end 94 0 which is secured to the chuck 64 by means of the bolt 95.

Previous attempts to wind worms by a similar method have found it necessary to support the flight at one or more points along the core where the forming was taking place. With our method such supports are unnecessary since the test of the proper winding of the worm resides in a complete balance of the stress set up within as manifested in the perfect axial alignment of the worm produced by our process.

Throughout this specification, we have referred to rolled steel in order to distinguish our process from those employed in the manufacture of cast metal worms. It must be distinctly understood that we are especially interested in the formaf tion of worms from cold rolled stock. having a smooth finish and that this finish is not marred in any way in the coiling or winding process itself. No heat whatsoever is employed except for the purpose of welding the flight to the core.

It will be understood that we are fully aware that rolled steel worms have been constructed in sections and that worm flights have been made of discs which were split and subsequently joined and that worm flights have been constructed by rolling a flat bar into a helical form by stretching one side thereof and that in at least one instance, helical worms havebeen made by winding a bar on edge in close fashion and later stretching the wound bar to the desired pitch. Our method is distinguished from those referred to by the precise control of the twist imparted to the bar and the angle at which said bar is guided bears to the helical angle of the worm being formed. It is this advancement in the art which we intend to cover in the following claims:

1. A method of forming rolled steel worms at the desired helical angle consisting of coiling a bar on edge directly upon a worm core while defiecting it away from its true helical and radial angles prior to its mounting said core.

2. A method of forming rolled steel worms consisting of progressively moving one end of a flat bar around a supporting core holding said bar approximately at a tangent to the helix to be formed, then imparting a twisting action to said bar in a manner to urge same away from a plane which is radial to the worm axis near a point where said bar leads upon said supporting core.

3. An apparatus for forming rolled steel worms consisting of a means for holding a worm core, means for holding one end of a flat bar with one edge tangent to said core, means for rotating the held end of said bar around said core, means for holding said bar at substantially the helical angle of said worm and adjustable means for accurately controlling and applying a twisting action to said bar as it mounts upon said core.

4. An apparatus for forming rolled steel worms consisting of a flight coiling machine having 1 means for carrying one end of a flat bar about the

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