US3047245A - Adjustable cam means for winding machines - Google Patents

Description

Jul 31, 1962 H. A. GEORGE 3,047,245

7 A ADJUSTABLE CAM MEANS FOR WINDING MACHINES Filed Jan. 20, 1960 2 Sheets-Sheet 1 PRIOR ART INVENTOR l/a wnno A. 65026:

ATTORNEY July 31, 1962 H. A. GEORGE 3,047,245

ADJUSTABLE CAM MEANS FOR WINDING MACHINES Filed Jan. 20, 1960 2 Sheets-Sheet 2 Illllllllll ATTORNEY United States This invention relates to adjustable cam means and methods for making the same, and more particularly, to such apparatus and means for coil winding machines.

This application is a continuation in part of my prior application of the same title S.N. 420,031, filed March 31, 1954, now abandoned.

The use of cams is widespread in the winding of electrical coils, as well as in the textile industry. In general, these cams control the motion of the wire guide which distributes the wire in a predetermined pattern on the coil itself, as shown in FIGURE 8. Up until the present time, most cams were shaped specifically for the coil to be wound and the shape or size of the coil could not be conveniently modified. Various devices have been used to overcome this diiiiculty by employing levers or similar multiplying devices which generally introduced errors in the traverse of the winding guide as compared to the original cam surface. Some of these errors result from the geometry of the amplifying members, but additional errors arise from the mechanical difiiculties involved in making all pivot points slack free. The cam of the present invention preserves the desirable feature of direct action on the wire guide without pivots, levers, or other error producing mechanisms. At the same time, it provides an opportunity for accurate control and calibration of the length (or shape) of the traverse.

The adjustable cam of the present invention provides means for adjusting and modifying the throw of the cam without changing cams, and even for making fine adjustments while the machine is running. This reduces set-up time tremendously and provides products which could not be made with standard size cams.

Accordingly, a principal object of the present invention is to provide new and improved adjustable cam means.

Another object of the present invention is to provide new and improved adjustable earn means for coil winding machines.

Another object of the present invention is to provide new and improved cam means for providing a smoothly adjustable throw, thereby eliminating the need for a multiplicity of different cam sizes or-shapes.

Another object of the present invention is to provide new and improved means for winding coils including means for adjusting the throw of the wire leading means without the removal of any parts.

Another object of the present invention is to provide new and improved coil winding apparatus including means for adjusting the cam throw of the apparatus while it is in operation.

Another object of the present invention is to provide new and improved coil winding apparatus comprising a cam for a smoothly adjustable throw at difierent planes along its axis, wire leading means adapted to be moved by said cam, and means to move said cam along its axis to adjust said throw.

Another object of the invention is to provide new and improved means to move a coil form and means to coordinate movement of the'coil form and'wire guide.

Another object of the invention is to provide new and improved means to make special coils.

Another object of the invention is to provide new and improved means to make progressive and bank wound coils.

Another object of the present invention is to provide new and improved three dimensional adjustable cam means.

These and other objects of the invention will be apparent from the following specification and drawings of which:

FIGURE 1 is a perspective view of a conventional heart-shaped cam.

FIGURE 2 is a perspective view of a cam formed in accordance with the present invention.

FIGURE 3 is a plan view of the cam shown in the embodiment of FIGURE 2.

FIGURES 4 and 5 are sectional views of the cam shown in FIGURE 3 taken along lines 4-4 and 55 respectively.

FIGURE 6 is a side view of the cam shown in FIG- URE 3.

FIGURE 7 is a plan view of apparatus for generating or manufacturing a cam according to the present invention.

FIGURE 8 is a perspective schematic view showing coil winding apparatus constructed in accordance with the present invention.

FIGURE 9 is a perspective view of another cam embodiment of the invention for winding bank coils.

FIGURE 10 is a perspective view of another cam embodiment of the invention designed for winding progressive universal coils.

FIGURE 1 illustrates a conventional heart shaped cam 1 commonly employed in some coil winding mechanisms. A cam with a constant displacement for each degree of rotation is shown since this is the most used mot-ion. The symmetrical design provides for a linear traverse in of rotation and a traverse, also linear, in the opposite direction for the remaining 180'. It should be noted that the shape of the follower 9' mechanism, affects the linearity of the resultant motion. This is shown by the dotted line 8 which traces the path of the follower as the cam rotates. The path is shown to meet the above conditions although the surface on the cam would not. These comments are made to point out a fact which otherwise might introduce confusion later.

The effective throw of the cam in FIGURE 1 is the diiference between the minimum and maximum dimensions of the cam, i.e. BA.

FIGURE 2 shows an embodiment of a cam of the present invention. It is heart shaped at one end 2' to provide a throw BA as in FIGURE 1. It is circular at the other end 3 which provides zero throw since A=B. Between the two ends it is smoothly tapering. Intermediate sections like 4 are heart shaped and have a corresponding intermediate throw. For instance, if the heart face 2 has a throw of .250" and the circular end 3: has a throw of .000", then all thro'ws between these limits are obtainable by moving the cam along its axis. Intermediate throws dilfer in size but not in characteristic shape.

The subject cam may be thought of as a multitude of flat cams as in FIGURE 1, assembled with the X axis in the same plane with a common mounting hole. For the full advantage of this design the sum of A+B must be constant for all the unit cams. This stack of cams is so arranged that the throw as defined above increases progressively and uniformly from one end of thestack to the other. In visualizing a single, unit so constructed the individuallcams may be thought of as approaching infinity in number so that the surface on which the follower rides is smooth and uniform. The resulting unit will act in the same manner as thecam described in FIGURE 1, but the throw of this cam will depend upon the location of a spherical follower along the shaftway axis of the cam. By moving the follower or the cam along its axis the throw may be changed at will. This approach should give a general concept of this cam.

A second method of describing this cam of FIG. 2 would be to make certain specifications about points and lines which lie on its surface. Intermediate points and the shape of the cam surface may be induced from these factors.

The following comments are actually based on the traverse of the follower although for convenience we shall refer to the surface of the cam as though it were one and the same thing. (This condition could only be met if the follower were actually a point rather than a sphere with an appreciable radius.)

In FIGURE 3 the X axis is constructed so as to pass through the minimum and maximum dimensions of the heart face of the cam which are 180 apart by previous definition. The Y axis is originally placed at a 90 position to the X axis, so as to intersect the X axis at the center of rotation of the cam. By previous definition it should be noted that A+B=A+B'. It should also be noted that with the Y axis in the 90 position A=B'. If the Y axis is rotated clockwise so that it approaches X axis, A will decrease uniformly with rotation until it equals A, while B will increase accordingly to B, the fundamental relationships mentioned above remaining: i.e. A-i-B=A'+B'. While all of this discussion could properly have been applied to a single cam as in FIG- URE l, the subject cam is a three dimensional concept which meets these requirements at any plane perpendicular to its axis. It should be further stated that a section through the cam parallel to its axis on the line X-X will show a section which is a parallelogram as in FIG- URE 5, while a section taken through the axis YY' is a rectangle as in FIGURE 4. Any section taken on the line Y--Y as it rotates toward XX' is a transition from the rectangle to the parallelogram in which the angle 0 FIG. 5, is constantly becoming more acute. FIG- URE 6 is a left side view of FIGURE 3.

Another method of defining the shape of this cam may be by means of discussing its method of generation. In FIGURE 7, the cam 10 is mounted on a spindle 11 such as in a lathe 19. A motor driven cutting tool such as an end-mill 12 is mounted on a rotating table 13, the rotation of this table being linked to the spindle on which the cam is mounted through suitable worm 14, spur 15 gearing and change gears 11'. The solid lines show the position of the rotating end mill 12 at the 90 or mid point of the generating motion, while the upper and lower dotted positions show the location of the end mill at the minimum and maximum tarverse of the generated cam. Suitable change gears 11 are used to achieve the desired traverse in 180 of cam generation. It should be noted that the end mill 12 which generates the surface of the cam is preferably of the same radius as the sphere which is to be the cam follower. The center of the end mill traverses a path indicated by the dotted line 8, in FIGURE 1, while the cutting edge of the end mill follows the desired contour. curacy, the spindle 11 holding the cam 10 and the axis of the cutter 13 must not only be parallel at the 90 point, but must lie in the same plane at all times.

It is further noted that in addition to the concepts mentioned above, the apparatus shown in FIGURE 7 suggests the following:

If the center of rotation 13' of the table 13 on which the cutting tool is attached coincides with the plane of either face of the cam as shown in FIG. 17, then that face is circular and has a zero throw. If this pivot point falls between the two faces of the cam, then the resulting unit has a O or null point at a corresponding plane. On each side of this point lie planes which produce throws equal but opposite to each other and progressively larger. If the pivot point falls outside of the cam, then no zero throw exists and the resulting cam provides adjustment between the limits available at each heart shaped face.

To produce cams of maximum ac Referring to FIGURE 8, it is general practice in machines of this type to make the movement or motion of the winding finger positive in both directions. This is accomplished by using two points of contact of the cam follower 20 on the cam, rather than one. In FIG- URE 1, this second point would be at the apex of the cam and is always located 180 from the first point. In other words, the two points of contact are in a line which passes through the center of the shaft on which the cam is mounted. The distance between these two followers is represented by A-l-B and is therefore constant. The cam of the present design is of such shape that A+B is constant for any two points on its surface lying in the same plane through the shaftway axis, and, therefore, no new compensating device need be introduced. To adapt a standard machine to this unit requires only that a method of moving the cam shaft along its axis be provided. A suitable method of calibration is also desirable.

FIGURE 8 shows a schematic of such a coil winding machine design. The wire 33 is fed onto the coil form 34. The wire leading arm 35 is mounted on shaft 36 which is actuated axially by the action of cam 37, and cam follower yoke 20, to provide the desired coil shape. The coil form 34 is adapted to be rotated by spindle 23. In certain applications, the spindle 23 is also moved axially by rack 76, for winding certain type coils such as, for example, progressive universal or bank wound type coils.

Power is applied by driving means 23' which drives spindle 23", spindle 23 is connected to spindle 23" by spline connectors to permit axial movement of the spindle 23 which is mounted on rack 76 by bracket 77, and collar 78.

Gears 50 and 51 are change gears used to secure satisfactory turns per layer or suitable cross over pattern for the winding of a specific coil, 50, being the driver gear which is mounted on a drive shaft 22 driven through a worm gear arrangement or other means such as right angle drive 52, 52' by the spindle 23. 53 is a bracket holding an elevated idler gear 54 which may be placed at a convenient position for linking the two change gears, 50 and 51. 55 is the cam shaft which carries the driven gear 51 on one end and the adjustable cam 37 on the other. The shaft 55 rotates in bushing 56 which is prevented from rotating by a key 57 or similar device. 58 is a gear which has internal threads in the hub to fit similar threads 59 on bushing 56. It should be noted that gear 58 is secured against movement along its axis by solidly mounted bracket 60. Bushing 56 and shaft 55 have collars or shoulders (not shown) so that when bushing 56 is moved axially the shaft 55 is also moved axially. Thus, rotation of gear 58 results in the axial movement of the entire assembly consisting of gear 51, shaft 55, hub 56 and cam 37.

This brings the desired area of the cam into contact with the cam follower points on yoke 20. Idler gear 54 has teeth of sufficient length that change gear 51 remains in mesh with it regardless of the position of the cam shaft 55. To provide conventional adjustment and calibration for this device, shaft 62 has a small pinion gear 63 which engages gear 58 and a worm 64, and suitable means of attaching a wrench or knob 65, by which the actual adjustment is made. The worm 64 engages a gear 66 on vertical shaft 67 which carries an indicating pointer 68 on its upper end. The gear ratios are preferably so chosen that one revolution of the indicating hand covers the full range of cam adjustment. The hand is secured in such a fashion that its position in relation to the shaft can be altered for calibration. When it is desired to move the coil form 34 axially for progressive universal or bank wound coils, knob 79 is pushed in thereby connecting rack 76 to the driving source via gear 75 which engages the rack gear 74, idler 72 on bracket 73, gears 71 and 70 to driver spindle 23"". Gears 71 and 74 are change gears, which may be changed to provide the desired rack movement.

Among the advantages of an adjustable cam throw are economy of equipment, ease of setup, flexibility and This particular design has other advanconvenience. tages and applications beyond those available in other equipment designed for similar purposes.

Speed of operati0n.-'I'he yoke and follower design used with this cam and shown in FIGURE 8 represents the very minimum weight in the reciprocating parts. In fact, no additional reciprocating parts have been added to utilize this cam and soits use does not curtail the operating speed.

Direct action.The design of this cam permits continued use of the very desirable feature of having the cam act directly; i.e. rather than through levers or pivots. Mechanisms employing pivot joints or sliding members depend on their fit for accurate results. In this design the accuracy of the cam surface alone determines the accuracy of the movement of the wire guide.

Low c0st.--Previously accuracy and speed mentioned above could be obtained only by using cams of a specified and unalterable throw. If such cams are to be manufactured with reasonable accuracy their cost is not inconsiderable and a group of cams to give a continuous range equal to one of the cams of the adjustable type would cost a great deal more than the single cam.

C0nvenience.-The convenience of this design is manifold. In determining a satisfactory coil setup, previous procedure involved the manufacture or purchase of a cam of definite specified size and shape. Once this cam was procured experience might show that a cam slightly different in size or shape should be tried. The attendant delays in securing a cam to the new specifications often proved considerable. With this design, these compensations can be made immediately.

An additional convenience is that the necessity of removing one cam and installing a substitute is eliminated. Since the cam follower spacing might vary from cam to cam this adjustment is also eliminated by the new design.

Self-centering feature.A cam of the design mentioned above not only provides for an accurate and continuous adjustment of the length of traverse of the winding button, but also makes this adjustment of equal effect at each end of the stroke. When this stroke of the cam is adjusted, therefore, the coil continues to be wound in the same area. With bobbins (flanged fors) this means that the cam adjustment can be used to secure even buildup to each flange.

Adaptability.While the specific design described is basically a linear, constant Velocity, constant displacement unit, this need not be a limiting specification in the design. Non-linear cams may be constructed which likewise have the advantage of adjustment using the mechanism described herein.

Once the general structure of the basic cam is understood and a mechanism provided to utilize the adjustable features, variations and deviations from the cam form may be made for specific applications. In these cases certain features which may not be needed for the problem at hand may be sacrificed in order to secure further advantages. Two such cam forms are described below, in connection with FIGS. 9 and 10. In both of these illustrations the condition A+B equals A'-]-B' is sacrificed. This means that a spring loading on the left hand follower in FIGURE 8 must be used. The right hand follower alone determines the motion of the winding wire guide. (This spring is often used with the original cam design to eliminate errors due to wear of the machine or other factors.)

In the winding of the so-called bank-wound coils successive turns are wound on top of the preceding one running up a bank at approximately a 60 angle from the core axis. Each of these turns is thought of as belonging to a separate layer and thus, a six layer bank wound coil would have six such turns and the seventh turn would be preceded by a rapid excursion down the slope of the bank to the core on which the coil is wound. Starting with the seventh turn, the process is repeated. The problem of displacement of the rapid return to secure suitable nesting of the turns does not affect the cam design and is not a part of this description. In winding a bank wound coil it is customary to depend ppon the cam to produce the basic motion of the winding finger and at the same time a suitable means of moving the coil along its axis must be provided so that when the winding finger has returned for turn seven to the place it occupied for turn one, then the coil will have been displaced one wire diameter, the combination of these two motions providing the desired pattern.

FIGURE 9 illustrates the approximate shape of a cam for this purpose. Since the placement of these turns is very critical, the amount of throw in the cam must be adjusted very closely and generally must be determined by trial. If a cam is made of an appearance similar to FIG. 9, in which the one end 30 is a circle and the opposite end 31 is a cam of the indicated spiral shape, then this adjustment can be made using the mechanism we have described in FIG. 8.

Referring to FIG. 10, a second cam variation is designed for the more "accurate winding of the so-called progressive-universal coil. This winding is produced by having a wire guide place the wire in a path very similar to that used for the more common lattice, or universal coils, while at the same time the coil form is moved along its axis at a uniform slow rate. The winding of lattice patterns has been developed until 'a very stable pattern has been achieved. This results from a careful balancing of the various factors such as wire size, cam throw, and coil diameter. When a progressive universal coil is wound, these critical calculations are upset since the rate of traverse of the constant progression is added to the rate of traverse produced by the same in one direction of its throw and is subtracted from it in the other direction. It is possible to displace the nodes on a cam so that they are not 180 apart, thus altering the rate of traverse in both directions. In this manner, it is possible to wind a progressive universal coil of a quality equally as good mechanically as can be achieved with a simple universal pattern. The increased mechanical quality results in more uniform and stable electrical characteristics and this change materially reduces the distributed electrical capacity of the coil.

In designing an adjustable cam for such purpose, adjustment of the displacement (in degrees) rather than in distance is desired. In other words, such a cam has a constant amount of throw. One heart face 32 of this cam, FIG. 10, would have the maximum and minimum dimension; i.e. A+B dimensions, 180 apart. On the other face 42 these two dimensions will be separated by less than 180, generally about as shown in FIGURE 10. Using the mechanism described for adjustment this cam will provide any degree of displacement necessary to compensate for the progression of the coil. Coils with very slow progression will be wound near the face while coils with the most rapid progression will be wound near the 90 face.

I claim:

1. Coil winding means comprising a movable rack, a spindle rotatably mounted on said rack, drive means connected to rotate said spindle, movable gear means for connecting said drive means to said rack, a coil form on said spindle, a cam shaft mounted perpendicular to said rack and said spindle, a cam on said cam shaft, cam follower means mounted adjacent said cam and adapted to be oscillated by said cam, wire guide means connected to said cam follower means and extending over said coil form, a gear train connecting said driven spindle to said cam shaft including change gears for adjusting gear ratio, and means to move said cam shaft and cam axially to move said cam surface relative said cam follower.

2. Apparatus as in claim 1 wherein said last means comprises a hub mounting said cam shaft, said hub being movable axially with said cam shaft and having external threads thereon and an adjusting gear having internal threads mounted on said external threads, knob means connected to rotate said gear to move said cam shaft axially, and indicator means connected to said knob means.

3. Coil winding means comprising a movable rack, a spindle mounted on said rack, drive means connected to rotate said spindle, movable gear means for connecting;

said drive means to said rack, a coil form on said spindle, a cam shaft mounted perpendicular to said rack and said spindle, a cam on said cam shaft, cam follower means mounted adjacent said cam and adapted to 'be oscillated by said cam, wire guide means connected to said cam follower means and extending over said coil form, a gear train connecting said driven spindle to said cam shaft including change gears for adjusting gear ratio, and means i to move said cam shaft and cam'axially to move said cam surface relative said cam follower, comprising a hub mounting said cam shaft, said hub being movable axially and having external threads thereon and a gear having internal threads mounted on said external threads and means 605,984 Whyte June 21, 1898 1,927,547 Gordon Sept. 19, 1933 2,305,085 Jacob et a1. Dec. 15, 1942 2,771,250 Icenbice Nov. 20, 1956 FOREIGN PATENTS 21,686 Great Britain Sept. 23, 1910 110,705 Australia Oct. 10, 1928 412,315 Italy Nov. 26, 1945

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