ONE-WAY DRIVE DEVICE AND METHOD

TECHNICAL FIELD

[0001] The present invention relates generally to one-way drive devices and more particularly to improvements in planar type one way drive devices and the way they are manufactured.

BACKGROUND

[0002] Planer type one-way drive devices are well known in the art. In particular, attention is directed to a planer type one-way drive device described in United States Patent No. 5,070,978 to Pires (the "'978 Patent"), which is incorporated herein by reference. This Patent is owned by the assignee of the present application and is under license to another company which manufactures and sells one-way drive devices using the principles described in the '978 Patent.

[0003] Briefly summarized the one-way drive device disclosed in the '978 Patent, includes what the patent refers to as a strut plate and a receptor plate positioned in confronting relationship to one another. The strut plate in the '978 Patent includes a series of circumferentially spaced pockets, each of which receives a biasing spring and a strut movable within the pocket between a spring biased position in which the strut extends partially outside the pocket and a forced position in which it is located entirely within the pocket, as described in the '978 Patent. The receptor plate also includes a series of circumferentially spaced pockets which serve to engage the struts under specific conditions of operation of the one-way drive device, as described in the patent.

[0004] In the present application, a one-way drive device is disclosed which includes plates which are referred to as pocket and notch plates that correspond in certain respects, respectively, to the strut and receptor plates of the '978 Patent. The pocket plate includes corresponding pockets are referred to as notches rather than pockets. For additional structural and functional details, reference is made to the '978 Patent.

[0005] An actual commercial embodiment presently being manufactured and sold by the licensee mentioned above includes an integrally molded pocket plate having an

outwardly projecting, circumferential side wall designed to define a chamber, more or less, for receiving an integrally molded notch plate.

[0006] As will be seen, the one-way drive device disclosed and claimed herein provides for an improved drive device that has advantages over that disclosed in the '978 Patent, both structurally and in the way in which it is manufactured and assembled.

SUMMARY

[0007] In one aspect, the invention affords a one-way drive device comprising a pocket plate assembly including a disc-shaped pocket plate and a notch plate assembly including a disc-shaped notch plate, contained within an axially extending open-ended cylindrical shell. The shell has opposite first and second axial ends and opposing inner and outer circumferential surfaces which extend axially between the first and second ends. The surfaces are configured to include a plurality of circumferentially spaced, axially extending, radially inward and outward projecting shell splines, and first and second sets of tabs. The radially inward and outward projecting shell splines define an innermost annular bearing surface within the shell. The first and second sets of tabs are located adjacent to the first and second axial ends of the shell, respectively, and extend radially inward beyond the innermost annular bearing surface. The shell splines extend axially from the first end of the shell to the second end of the shell, except where the first and second sets of tabs are located.

[0008] The shell is formed from an elongated sheet of metal having end edges which is rolled into a cylindrical shape with its end edges fixedly connected together to form an open ended cylinder. Alternately, the shell may be formed by plastically extruding it in a corrugated shape from molten or otherwise made plastic metal, and subsequently slicing the extrusion into parts having the appropriate axial length. The shell splines and tabs are integrally formed in the sheet of metal, and each of the tabs is stamped or otherwise deformed radially inward from a segment of an associated one of the shell splines.

[0009] In accordance with another aspect, a method is provided in which the cylindrical shell including its splines is first made. Thereafter, the first set of tabs is formed adjacent to a first axial end of the shell, after which the pocket plate assembly and the notch plate assembly are introduced into the shell such that one of these plate assemblies interlocks in a splined fashion within the shell while the other plate assembly

is radially located for movement and cooperation with the first plate assembly within the shell by the inner annular surfaces of the splines. The assemblies have struts and cooperating pockets that function as interlocks so they serve as a one-way drive device. Thereafter, a disc-shaped washer is positioned within the shell and interlocked with a spline. The washer is axially retained by the second set of tabs, and locks the plate assemblies in cooperating relationship within the shell.

[0010] Further aspects of the improved one-way drive device and the method by which it is made and assembled will be described and shown in the following detailed description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is an exploded perspective view of a one-way drive device in accordance with the invention; and

[0012] Figure 2 is a perspective view of the device of Figure 1 shown in an assembled state.

DETAILED DESCRIPTION

[0013] Turning now to the drawings wherein like components are designated by like reference numerals in the two figures, attention is first directed to Figure 1 which illustrates a one-way drive device generally indicated by the reference number 10, in accordance with the invention. This one-way drive device may include an axially extending open-ended cylindrical shell 12 having opposite first and second open ends 14 and 16 and opposing inner and outer circumferential surfaces 18 and 20 that extend axially between the ends 14 and 16. The opposing inner and outer circumferential surfaces together are configured to provide a plurality of circumferentially spaced and axially extending, radially inward and outward projecting shell splines 22 having radially innermost surface edges 24, which together define an innermost annular bearing surface 25, generally indicated in Figure 2.

[0014] Still referring to Figure 1 , shell 12 also may have a first set of tabs 26 formed therein between adjacent splines and located adjacent to the first axial end 14 of the shell. These first tabs extend radially inward beyond the innermost annular bearing

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surface 25, for the reasons to be described hereinafter. The shell may also include a second set of tabs 28 formed therein between adjacent splines and located adjacent to the second axial end of the shell. Like the first tabs 26, the second tabs 28 may extend radially inward beyond the innermost annular bearing surface 25 as best seen in Figure 2, again for reasons to be explained hereinafter. As illustrated in both Figures 1 and 2, the tabs of each set may be spaced circumferentially around the shell, preferably symmetrically. While twelve such tabs are shown at each end of the shell, it will become apparent that there may be a greater or lesser number of tabs so long as the tabs function in the intended manner that will be described. Moreover, the way in which this shell assembly (that is, the shell including its splines and tabs) is made in accordance with one embodiment will be described hereinafter.

[0015] Still referring to Figure 1 , in addition to shell 12, the one-way drive device 10 also includes a pocket plate assembly 29 including a disc-shaped pocket plate 30 disposed within shell 12 between the first and second sets of tabs 26 and 28, respectively. This disc-shaped pocket plate has opposing planar sides including a series of circumferentially spaced pockets 32 and an outermost circumferential periphery defining circumferentially spaced splines 34. These splines 34 are interlocked for rotation with cooperating ones of the shell splines 22 at a circumferential location adjacent to the first set of tabs 26. Within each pocket 32 in pocket plate 30, the pocket plate assembly 29 may include a strut 36 and a cooperating biasing member 38, for example a spring in the illustrated embodiment, such that the strut is moveable within its pocket between a biased driving position and an overrun position as will be described below. The whole assembly 10 may connect with a first external rotating element (not shown) by means of the splines 22 on the outer surface of the spline shell 12. The assembly 10 may also connect with a second external rotating element (not shown) by means of the inner spline surface of a pocket plate to be described.

[0016] In the embodiment illustrated in Figures 1 and 2, the pocket plate assembly 29 is positioned within the shell 12 such that pocket plate 30 rests against the set of tabs 26 which extend sufficiently radially inward to prevent the pocket plate from moving out of the shell in the direction of those tabs. At the same time, as indicated previously, the splines 34 of the pocket plate cooperate with the splines 22 of the shell so that the shell and pocket plate are interlocked and rotate as a single unit.

[0017] Still referring to Figure 1 , one-way drive device 10 may further include a notch plate assembly 39 which comprises a notch plate 40. Notch plate 40 may also be discshaped and include opposing planer sides having a series of circumferentially spaced notches 42 formed therein. Notches are configured to engage periodically one of the struts 36 when the strut is in a biased driving position at which the strut extends at least partially out of its pocket, and when the pocket and notch plates rotate in predetermined directions relative to one another, as will be described hereinafter and as is well know with regard to planar type one-way drive devices. The notch plate defines an outermost circumferential periphery 44 that serves as an outermost annular bearing surface. To that end, the notch plate is preferably dimensioned such that its outermost circumferential periphery 44 is located slightly radially inward of and in sliding confronting relationship with the innermost annular bearing surface 25 of shell 12 when the notch plate is properly assembled within the shell, in the manner to be described below. A number of circumferentially spaced axially extending channels or passageways 45 may be provided in the periphery 44 of the notch plate to accommodate the passage of oil within the device. The notch plate may also include an innermost circumferential periphery 46 having appropriately configured splines 47 designed to interlock with an external drive or driven member (not shown).

[0018] Once the pocket plate assembly 39 is located within shell 12 with pocket plate 30 and engaging tabs 26, the notch plate assembly may be positioned within the shell with its notch plate 40 engaging the pocket plate such that the spring biased struts 36 carried by the pocket plate and the notches 42 carried by the notch plate cooperate with one another in the typical one-way drive operation to be described briefly below and described in detail in the '978 Patent referenced previously. To this end, the notch plate is mounted for rotation about an axis (the axis of the drive or driven member to which it is adapted to be attached) which is co-extensive with the axes of the shell and pocket plate.

[0019] In addition to the shell 12 including its splines and tabs, the pocket plate assembly 29 and the notch plate assembly 39, the overall one-way drive device 10 may also include an oil controlling annular-shaped end washer 50 having a splined outer periphery 52 configured and dimensioned to interlock with splines 22 of shell 12. In particular, once the pocket plate assembly and the notch plate assembly are assembled within the shell 12 in the manner described above, that is, after the tabs 26 are formed in

the manner to be described but before the tabs 28 are formed, the washer 50 may be located within the shell against the side of notch plate 40 opposite pocket plate 30. Once the washer 50 is so positioned, the tabs 28 may be formed in the manner to be described, thereby locking the washer inside the shell by virtue of the fact that they extend radially inward beyond the outermost periphery of the washer. Indeed, the tabs 26 on one side of the shell and the tabs 28 on the other lock the notch plate assembly, the pocket plate assembly, and the washer together in a sandwiched configuration such that the pocket plate and the washer rotate with the shell as a single unit while the notch plate is free to rotate relative to and cooperate with the pocket plate in the manner to be described.

[0020] Before describing the way in which one-way drive device 10 operates, the preferred way in which it is made and assembled in accordance with one particular embodiment disclosed herein will be described. The shell itself may begin as a thin strip of metal material, for example, a low carbon steel sheet material having a thickness of approximately 0.040 inches (approximately 1 millimeter). The length of this sheet material and its width may be selected based upon the intended diameter of the ultimately formed shell and its axial length. For example, in one embodiment of device 10, the inner diameter of the shell, that is, the diameter of its radially inwardly facing bearing surface 24, is 5.51 inches (approximately 140 millimeters) and the axial length of the shell is 0.880 inches (approximately 22 millimeters). These various dimensions are being provided and indeed the material itself making up the shell are provided for exemplary purposes only and are not intended to limit the claims appended hereto. As will be appreciated, other dimensions and other materials may also be used. Based upon the teachings herein and the desired application, one of ordinary skill in the art can readily provide the necessary material and dimensions based upon the intended use.

[0021] Once the sheet of metal material for making the shell is provided, either of two alternatives may be used to form the splices 22 and tabs 26 and 28. These may be first formed in the strip of material, and it may be then rolled into an open ended cylindrical shape of the shell. Alternatively, the sheet material may be first rolled into a cylindrical shape and the splines and tabs formed thereafter. Indeed, the splines can be provided first before the sheet material is formed into the cylindrical shape of shell 12, and then the tabs may be provided thereafter. In any event, once the sheet material is rolled into

the cylindrical shape of the shell, its adjoining ends may be welded, crimped or otherwise fixedly connected in any suitable manner.

[0022] At this point, the shell material may be in the form of a simple hoop (without its splines) which has the correct axial dimension, but which will have a substantially greater diameter than the desired diameter of the finished shell (sufficient to permit the splines to be formed in the hoop). This hoop may be then rotated between a mating pair of corrugating wheels that resemble a loosely fitting gear set to form the splines. The size and spacing of the teeth in these wheels are such that they form the sheet material of the hoop into the desired corrugated shape with the correct diameter.

[0023] An alternate method of forming the shell is to extrude a tube of the desired shape. The extrusion would be formed by forcing molten or otherwise plasticized metal through forming dies of the appropriate shape to create a tube with a spline shaped inner diameter and of the desired wall thickness. This tube, of arbitrary length, would then be cut into pieces of the desired axial length.

[0024] While the splines 22 can be provided in shell 12, either before or after the shell is formed from the sheet material, the tabs themselves in this particular embodiment can only be made after formation of the splines. The way this is accomplished is best illustrated in Figure 2.

[0025] As seen in Figure 2, one of the tabs 28, which for clarity will be referred to as tab 28a, as viewed from above, may be formed, while a somewhat diametrically opposite tab 28b as viewed from its underside may be formed. As shown, tab 28a extends from one spline 22 not to the next spline which will be labeled 22a, but to the spline 22 thereafter such that a spline 22a is disposed adjacent to and made shorter axially by tab 28a. This is because the tab 28a is formed using an end segment of spline 22a. In particular, before the tab 28a is ever formed, but after the spline 22a is formed, a slit 52 may be made into the slpine a short distance from its end, as shown in Figure 2. Once the slit is made, a suitable deforming device, for example a punch or striker, may be used to push the segment of spline 22a between the slit and the end of the shell radially inward such that it forms the tab. This radially inward deformation, best illustrated by tab 28b, allows the tab to project radially inward beyond the innermost bearing surface 24. All of the tabs 26 and 28 may be formed in this manner in the embodiment disclosed.

[0026] Moreover, while the present embodiment discloses tabs 26 and 28 that are axially aligned, that is, using the same splines to form them, it will be understood that the present embodiment is not limited to the axial alignment of tabs. Indeed, one-way drive device 10 is not limited to this particular way of forming the tabs themselves, although it is a relatively simple, uncomplicated, and economical way of doing so. They could be provided by welding or soldering in place a separate, small block of material into a spline. Further, while the shell 10 is shown as including twelve tabs 26 and twelve tabs 28, it will be appreciated that the one-way drive device is not limited to that number of tabs. The number of tabs may vary from device to device, depending upon the dimensions of the device, the material being used and its application, and possibly other factors that may be readily determined by those with skill in the art.

[0027] Turning now to the pocket plate 30, the notch plate 40, and the end washer 50, attention is directed to the way in which they are provided. In each case, in the embodiment illustrated, each of these components may be integrally stamp formed from a sheet of metal or other suitable material. In the case of the pocket plate, splines 34 may be simultaneously stamp formed into its outer periphery, or formed by means of partial piercing, and pockets 32 may similarly be formed by means of partial piercing. In the case of the notch plate 40, oil flow channels 45 and inner splines 46 can be stamp formed when forming the rest of the plate. Notches 42, however, may be formed by means of partial piercing in the same manner as the pockets are formed in the pocket plate. This partial piercing process is described in co-pending United States application serial number 1 1/455,320, filed June 19, 2006, entitled ONE-WAY DRIVE DEVICE AND METHOD OF MAKING THE SAME and assigned to the assignee of the present application. Finally, the end washer 50 can be readily stamp formed along with its outer splines 52.

[0028] While the methods of forming the pocket and notch plates and the washer, as described immediately above is a preferred way of making these components, it will be appreciated that device 10 is not limited to components formed in that way.

[0029] Clearly, the pocket plate assembly, notch plate assembly, and end washer can be formed and provided in any particular order as long as they are all available when the one-way drive device is to be assembled. This is also true of the shell, with one exception that should be apparent from the foregoing discussions. The shell has to be

made with the splines and, preferably, with one of the sets of tabs in place, for example, tabs 26, so that the pocket plate assembly, notch plate assembly, and end washer can be inserted into the shell in the manner described previously from the other end of the shell, that is, the end ultimately including tabs 28. Once the pocket plate assembly, notch plate assembly, and end washer are assembled in the shell, the tabs 28 can be formed in the shell to lock everything in place.

[0030] Once the one-way drive device 10 is assembled in the manner just described, it can be readily connected to drive and driven members (not shown) in a conventional manner, for example, as described in the '978 Patent. In particular, the pocket plate 30 can be connected with a drive member such that the pocket plate, shell and end washer rotate as a single unit in either a clockwise or counter-clockwise direction. When the pocket plate is caused to rotate in one direction, it is allowed to rotate freely relative to the notch plate, that is, in the overrunning direction. This is because in that direction none of the struts engage and lock into any of the notches in the notch plate. However, when the pocket plate is rotated in the opposite direction, at least one of the struts will eventually be moved by its biasing member to lock into engagement with a cooperating notch. This causes the notch plate to rotate with the pocket plate, or if the notch plate is locked in place by an external member, it will prevent the pocket plate from rotating in that direction. This particular way in which one-way drive devices of the type to which the invention pertains operate is not new. For a more detailed description of this general type of one-way drive device operation, reference is made to the '978 Patent.

[0031] Returning to Figure 1 , an additional point should be made here. The one-way drive device described in conjunction with Figure 1 has the pocket plate assembly 29 interlocked with the shell 12 for movement with the shell. It will be understood, however, that the pocket plate assembly and the notch plate assembly may readily reverse roles in this regard. That is, the notch plate assembly 39 may be provided with outermost splines and dimensioned to interlock with shell 12 adjacent tabs 26 so that the notch plate rotates with the shell, while the pocket plate of the pocket plate assembly may be made slightly smaller radially and provided, for example, with oil flow channels so the pocket plate may move relative to the notch plate and shell. In this latter case, the pocket plate assembly could then be positioned between the notch plate assembly and the washer.