GB2153044A

GB2153044A - Flexible blade coupling

Info

Publication number: GB2153044A
Application number: GB08501063A
Authority: GB
Inventors: Jean-Marie Watremez; Andre Antoine Seignez
Original assignee: Compagnie Engrenages et Reducteurs Messian Durand SA
Current assignee: Compagnie Engrenages et Reducteurs Messian Durand SA
Priority date: 1984-01-17
Filing date: 1985-01-16
Publication date: 1985-08-14
Also published as: FR2558225B1; GB8501063D0; IT1182362B; BE901506A; IT8567038A1; IT8552852V0; DE3501415A1; FR2558225A1; IT8567038A0; GB2153044B

Abstract

The flexible coupling consists of a stack of distinct arms or blades (1, 2), arranged in a polygonal structure (D), each of the two ends (4) of each of said arms being provided with a fastening hole, said arms being assembled together by means of fastening means inserted through the aligned holes in the stacked arms. At least some of the arms in the stack have their center portions (1c, 2c), ie. their portions spanning between their two ends (4), lying entirely to one side of the line (D) joining the centers (3) of said two holes such that said center portions do no overlap the center portions of the axially adjacent arms in the stack. The invention provides a coupling having a high resistance to fatigue. <IMAGE>

Description

SPECIFICATION Flexible blade coupling There are a number of known mechanical couplings termed flexible blade, disk or membrane couplings, designed to connect driving means (drive shaft) with driven means (driven shaft) and being basically very rigid torsionally whilst having a certain bending flexibility, thus allowing slight misalignment of the driving and driven shafts.

Such a coupling can consist for example of a stack of separate arms arranged in a polygonal structure, each of the two ends of each of said arms being provided with a hole for fastening purposes, said arms being assembled together by means of fastening means inserted through the aligned holes in the stacked arms, at least some of the arms in the stack having their center portions, ie. that part of the arm lying between the two ends thereof containing the fastening holes thereof, entirely disposed to one side of the line joining the centers of said two holes such that there is some clearance between said center portion and said line and no overlap.

Bolts are used to attach the coupling alternately to the drive shaft and the driven shaft so that a certain flexibility is obtained between any two successive bolts attached to a same part.

In the prior art coupling, the metal blades are stacked on one another and held together by fastening bolts. The micro-friction occurring between two blades (each of which blades can be part of a group of blades cut from the same disk) is a source of corrosion tending to damage the coupling.

One solution which has been proposed to solve this problem consists in inserting a spacer between two successive blades. However this solution requires a long and difficult assembly process and therefore a costly one.

Moreover, if any spacers are left out or lost, the coupling will not operate correctly.

This invention is directed to obviating these disadvantaes by proposing a new shape for the blades and a new arrangement thereof.

It thus provides a coupling in which at least a first of two axially adjacent arms is of the above-mentioned type, with a center portion lying entirely to one side of the line joining the centers of the two fastening holes and spaced apart from said line, the center portion of said first arm not overlapping the center portion of the second of said two arms.

In fact, for reasons of simplifying assembly of the coupling, it is preferable to use arms grouped into a same disk. Accordingly, the following arrangements are preferred: -either the arms of the stack constitute the sides of polygon-shaped disks, the coupling device being built-up by stacking a plurality of disks configured so that for each arm of a first disk, the centers of the fastening holes whereof coincide with the centers of the fastening holes of an arm of a second disk adjacent to the first disk, the center portion of at least one of the said two arms of the first and second disks lies entirely to one side of the line joining said centers of said fastening holes and does not overlap the center portion of the other of the two arms;; -or the disks are of at least two different types, each disk of a first type consisting of arms whose center portions lie to the outside of the polygonal line joining the centers of the holes provided in said arms, whereas each disk of a second type consists of arms the center portions whereof lie inside said polygonal line; -or alternatively, the disks are all of the same type and are shaped as a polygon with an even number of sides, the successive arms of such a disk having their center portions lying alternately outside and inside the polygonal line joining the centers of the holes in the ends of said arms.

The arms of the coupling stack can also preferably be provided with means for securing them in their assembled configuration, said means being separate from those used to attach the coupling to the mechanical parts it is designed to connect, said securing means preferably consisting of: -either tubular members going through the aligned holes in said arms of the stack and having their ends attached to washer-like bearing parts applying against the outside surfaces of said stack; -or an adhesive coating on the edges of the ends of the various arms of the stack.

The improvements according to the invention thus provide the desired advantages, namely the avoidance of friction between the center portions of the stacked arms and the avoidance, resulting therefrom, of corrosionrelated damage to the coupling.

In addition, the invention ensures easy assembly of the coupling in the case where several arms are part of the same disk, and easy manufacture of the parts in the case where the various disks are all identical with a single model.

Finally, the securing of the various arms or disks together by means for securing them as assembled which are separate from the means for attaching them to the driving and driven parts enables efficient and reliable handling of the coupling as a unit.

The invention will be more readily understood and subsidiary features and advantages thereof become apparent from the following description of several embodiments given by way of example, with reference to the accompanying drawings in which: Figure 1 is a plan view of a flexible disk used in a coupling according to the invention; Figure 2 is a plan view of a coupling according to the invention using disks identical to that shown in Fig. 1; Figure 3 is a plan view of flexible blades or arms suitable for use in an alternative embodiment of the coupling shown in Fig. 2; Figures 4 and 5 are plan views of two distinct types of flexible disk used in making a coupling according to the invention; Figure 6 is a plan view of the coupling made with the disks of Figs. 4 and 5; Figure 7 is a plan view of a variant of the disk of Fig. 1;; Figure 8 is a plan view of a coupling according to the invention made entirely from disks identical to that of Fig. 7; Figure 9 is a plan view of an alternative embodiment of the coupling shown in Fig. 2, using two different types of disk, namely that of Fig. 2 and another type; Figure 10 is a plan view of an alternative embodiment of the disk shown in Fig. 1; Figures ii and 12 are cross-sectional views of couplings according to the invention showing two embodiments of means for securing the arms or disks of the couplings as assembled; and Figure 13 is a plan view of a coupling according to the invention fitted with means for securing it in its as-assembled configuration.

Fig. 1 shows a flexible disk with an overall hexagonal shape comprising six arms of two different types: three arms 1 of a first type and three arms 2 of a second type, with an arm of one type preceeding the following two arms of the other type.

The arms are arranged as follows in relation to the polygonal line D of a regular hexagon with six points 3: -each arm 1 or 2 extends substantially parallel to one side of line D, -the center portion 1 C of each arm 1 lies entirely outside polygonal line D, -center portion 2c of each arm 2 lies entirely inside polygonal line D, -center portions 1 C and 2c are spaced apart from polygonal line D and do not overlap the line, -end portions 4, which are common to an arm 1 and an arm 2, overlap polygonal line D and are each provided with a hole 5, the center of which coincides with a point or vertex of polygonal line D, -and the disk consists merely of arms 1 and 2 and is made of a flexible material, for example cut out from a steel sheet.

To make a coupling according to the invention merely requires, as illustrated in Fig. 2, stacking a plurality of disks like that shown in Fig. 1 such that the centers 3 of the holes 5 in the various stacked disks coincide and staggering each disk angularly in relation to the previous disk by one sixth of a turn (60 ) such that the two ends 4 of an arm 1 are placed above the two ends 4 of an arm 2 and so on, and securing the various disks of the stack as assembled.

The holes 5 allow passage of the bolts for fastening the stack to the driving and driven parts connected by the coupling, one bolt attaching the coupling to one of said parts and the next bolt attaching the coupling to the other of said parts and so on.

The same holes 5 also serve to assemble the disks independently of the coupling's fastening to the driving and driven parts by providing a passage for rivets 6, the head whereof 7 bears against one of the transverse faces of the stack and the end 8 whereof is bent back against a washer or cap 9 which itself bears against the other transverse face of the stack (Fig. 11), or providing a passage for hollow pins 10 the ends whereof are clinched back against bearing washers 11 on the two transverse faces of the stack (Fig. 12).

Alternatively, the superposed ends 4 of the various arms 1, 2 of the disks can have their edges 1 2 coated with an adhesive substance 13 (Fig. 13).

As can be seen from Fig. 2, the center portions 1 C and 2c of arms 1 and 2 are located to either side of the polgonal line D and, as concerns any two arms whose ends 4 are superposed, are separated by a space 14.

Only the ends 4 of the arms of successive disks are in mutual contact.

Obviously, if the arms 1 and 2 belonging to the same disk are shaped as illustrated in Figs. 1 and 2, this leaves open the option of adopting elementary arms 1 5 such as that shown in Fig. 3, comprising a center portion 1 sic and two ends 1 sue having holes 1 6 with centers 17. The main feature of such an arm 1 5 is that its center portion 1 sic is substantially parallel to the line F joining the hole centers 1 7 and is relieved with respect to said line so that it does not overlap it.

Fig. 7 shows a disk with six arms 1 and 2 having the same functional characteristics as that of Fig. 1 in spite of having a slightly different shape. Like parts in the two figures naturally bear like references.

Fig. 8 shows a coupling made with a stack of disks like the model in Fig. 7.

Fig. 9 shows a coupling similar to that of Fig. 2 (as well as to that of Fig. 8), except containing, in addition to the disks stacked as are those of the coupling of Fig. 2, a second type of disk 1 8 whose arms 1 9 extend into the spaces 14 between two center portions 1 C and 2c of arms 1 and 2 of the disks of the first type, without, nevertheless, coming into contact with said center portions 1 C and 2c.

Fig. 10 shows still another disk shape, similar to that of the disk of Fig. 1, but having only four arms: two arms 1 and two arms 2, parallel to the sides of the square polygonal line D. The functional features of this disk are analogous to those of the disk of Fig. 1 which will be discussed further hereinafter.

Figs. 4, 5 and 6 finally, relate to a variant, still according to the invention, of the disks of two distinct types and to the coupling made therefrom.

The disk of Fig. 4 has six arms 1 arranged in a manner similar to the arms 1 of Fig. 1 in relation to a polygonal line D established by a regular hexagon. The disk of Fig. 5 itself comprises six arms 2 also arranged relative to hexagonal polygonal line D similarly to the arms 2 of the disk in Fig. 1. Like parts in Figs. 1 and 2 and 4 through 6 bear like numbers and the same names.

The coupling of Fig. 6 is made by stacking the two types of disk illustrated respectively in Figs. 4 and 5, in alternation, with the centers 3 of the holes 5 in the various disks all aligned. Obviously, given the shapes of the arms 1 and 2, spaces 14 are left open between facing arms, without any overlapping occurring between the arms' center portions lcand 2c.

The advantages of the embodiments described are inherent, specifically, to the existence of these spaces 14.

In all the couplings illustrated (Figs. 2, 6, 8 and 9) as well as in any other couplings which could be made using disks such as that of Fig. 10, the center portions 1 c and 2c of disks in adjacent layers do not come into contact with one another, nor do they come into contact with the arms 1 9 of disks 1 8 of the coupling of Fig. 9. Only the ends 4 of the various arms touch. This absence of contact between the center portions 1 C and 2e removes all risk of friction between these parts and thus all risk of friction-induced corrosion.

The same result is obtained with disks such as those of Figs. 4 and 5, except that in this case two different types of disk must be fabricated.

This manufacturing requirement can nevertheless be avoided by using disks with arms 1 and 2 alternating (Figs. 1, 7 and 10) enabling couplings according to the invention to be fabricated with only one type of disk.

The number of arms in a disk (for example, six arms for the disks of Figs. 1, 4, 5, 7 and 8 and four for the disk of Fig. 10) is chosen according to coupling size and flexibility requirements.

In addition, the means for securing the couplings "as assembled", ie. the rivets 6-7-8 of Fig. 11, the pins 10 and washers 11 of Fig. 12, or the adhesive coatings 13 of Fig. 13, make these couplings easy to handle.

As shown in Fig. 9, a coupling according to the invention can even contain disks 18 of another type than those comprising arms 1 and/or 2 already described herein, provided it also contains elements having such arms 1 and 2 to enable the required spaces 14 to be formed.

Finally, the spaces 14 as well as the center voids of the various disks can be subsequently filled with another material, such as a vulcanizing plastic material for example.

The invention is not limited to the embodiments described and illustrated but rather extends to all the variants thereof which may occur to those skilled in the art without departing from the scope of the invention as outlined in the following claims.

Claims

1. Mechanical coupling of the flexible blade type consisting of a stack of separate arms arranged in a polygonal pattern, each of said arms having a fastening hole at each end, said arms being assembled together with fastening means inserted through the aligned holes of the stacked arms, at least some of the arms in the stack having their center portions, ie. that part of the arm lying between the two ends thereof containing the fastening holes thereof, entirely disposed to one side of the line joining the centers of said two holes such that there is some clearance between said center portion and said line and no overlap, wherein at least a first of two axially adjacent arms is of the previously mentioned type, with a center portion lying entirely to one side of the line joining the centers of the two fastening holes and spaced apart from said line, the center portion of said first arm not overlapping the center portion of the second of said two arms.

2. Coupling according to Claim 1, wherein said arms of the stack constitute the sides of polygon-shaped disks, the coupling being built-up by stacking a plurality of disks configured so that for each arm of a first disk, the centers of the fastening holes whereof coincide with the centers of the fastening holes of an arm of a second disk adjacent to the first disk, the center portion of at least one of the said two arms of the first and second disks lies entirely to one side of the line joining said centers of said fastening holes and does not overlap the center portion of the other of the two arms.

3. Coupling according to Claim 2, wherein said disks are of at least two different types, each disk of a first type consisting of arms whose center portions,lie to the outside of the polygonal line joining the centers of the holes provided in said arms, whereas each disk of a second type consists of arms the center portions whereof lie inside said polygonal line.

4. Coupling according to Claim 2, wherein said disks are all of the same type and are shaped as a polygon with an even number of sides, the successive arms of such a disk having their center portions lying alternately outside and inside the polygonal line joining the centers of the holes in the ends of said arms.

5. Coupling according to Claims 1 through 4, wherein means are provided for securing the arms thereof in their as-assem bled configuration, said means being separate from those used to attach the coupling to the mechanical parts it is designed to connect.

6. Coupling according to Claim 5, wherein said means for securing said stacked arms in their as-assembled configuration consist of tubular members going through the aligned holes in said stacked arms, the ends of said tubular members being attached to washerlike bearing parts applying against the outside surfaces of said stack.

7. Coupling according to Claim 5, wherein said means for securing said stacked arms in their as-assembled configuration consist of an adhesive coating on the edges of the ends of the various arms of the stack.

8. Flexible Blade Coupling substantially as herein described with reference to the accompanying drawings.