GB2284874A

GB2284874A - Snap-action coupling of a component to a shaft

Info

Publication number: GB2284874A
Application number: GB9325529A
Authority: GB
Inventors: Graham Trevor Cook; Anthony Raymond Coleman
Original assignee: Pitney Bowes PLC
Current assignee: Pitney Bowes PLC
Priority date: 1993-12-14
Filing date: 1993-12-14
Publication date: 1995-06-21
Anticipated expiration: 2013-12-14
Also published as: GB9325529D0; GB2284874B; DE4444087A1; ES2114425B1; ITMI942497A1; FR2713529B1; IT1276902B1; ES2114425A1; FR2713529A1; ITMI942497A0

Description

-I- 22848;m4 Component This invention relates to a component, in

particular a component which can be secured on or relative to an elongate member.

In manufacturing industry, there are many instances when it is desirable to secure components on, e.g., -rigid, elongate shafts. Examples of components which are frequently thus secured are roller hubs, gear wheels, pulley wheels, cams and optical encoder discs.

Hitherto, such components have been secured by a variety of means, including the employment of a friction or interference fit between the component and the shaft to which it is to be attached; key members inserted into corresponding apertures in the component and shaft; rivets; welding; spring clips; grub screws and adhesives. All of the aforementioned means for securing components are disadvantageous in mass-production is environments, where it is required to secure many components quickly with a high degree of reliability. Each of the aforementioned means is either time consuming to put into effect or requires specialised knowledge and skill. Additionally some of the known means require manufacturers to keep large stocks of fixing components such as clips or screws; or welding rods, adhesives and the'like.

According to the invention, there is provided a component adapted for securing relative to an elongate member, the component comprising an elongate aperture adapted to receive an elongate member; first and second resiliently deformable members extending in the longitudinal direction of the aperture and spaced from one another to define a pair of jaws; and an abutment spaced from the jaws in said longitudinal direction, the resiliently deformable members lying closer together in the vicinity of the jaws than in a further 'region spaced from the jaws such that, as the component and such an elongate member are moved one relative to the other, a protuberance secured on the elongate member may be advanced towards and forced between the jaws to lie in said further region of the resiliently deformable members, the abutment being so positioned that the protuberance is engageable therewith when disposed in said further region thereby to limit or prevent further relative movement between the component and such an elongate member unless the protuberance is forced in the reverse direction out of the jaws.

This arrangement advantageously permits the "snap" fitting of a component onto, e.g., a shaft having secured thereto a protuberance such that the component will be secured in a desired location.

Preferably, the aperture is generally circular. Thus, the component may readily accommodate the most common forms of drive shaft used in manufacturing. However, many other profiles of aperture are possible (e.g.

rectangular, square, triangular and other polygonal or irregular shapes).

Conveniently, the resiliently deformable members are secured on generally opposite sides of the aperture and extend from the aperture to define the jaws at a location spaced from the aperture. This feature allows the resiliently deformable members to be firmly secured on the component whilst still allowing for an adequate degree of flexing at the jaw ends thereof.

Preferably, at least one of the resiliently deformable members has a profile congruent with part of the periphery of the aperture, the member being adapted to support the component on an elongate member inserted into is the aperture.

This feature advantageously allows the resiliently deformable member, in addition to its function as defined above, to brace the component against, e.g., unwanted angular movement relative to the elongate member inserted into the aperture.

In a preferred embodiment, the resiliently deformable members are secured to the component on the periphery of the aperture. This feature advantageously allows the base of each resiliently deformable member to be secured adjacent the periphery of the aperture. Thus, the periphery of the aperture may constitute part of the resiliently deformable member in some embodiments.

Preferably, the resiliently deformable members are additionally spaced from one another at their ends attached to the component, and the aperture extends into the space or spaces between the resiliently deformable members.

This feature enhances the ability of the periphery of the aperture to act as part of the resiliently deformable member.

Conveniently, the resiliently deformable members define two pairs of jaws, adapted to receive a corresponding pair of protuberances, and a corresponding pair of abutments. This allows the component to be secured to the elongate member in a symmetrical manner if the pairs of jaws and abutments are appropriately arranged.

Conveniently, the or each abutment comprises a shoulder secured to the component and having formed therein a cup adapted to receive a protuberance. This design of abutment has been found to be particularly effective.

Preferably, the or each abutment lies on a respective plane between the aperture and the corresponding pair of jaws.

This feature advantageously allows an elongate member to be fed into the aperture via firstly the jaws and secondly the or each abutment before it reaches the aperture proper.

Preferably, the component is adapted for securing on an elongate member in the form of a rigid shaft having at least one locating member extending laterally therefrom.

In particularly preferred embodiments, the locating member is constituted as a cross pin inserted into an aperture extending transversely of the shaft so that the cross pin protrudes from the shaft on either side thereof.

There now follows a description of preferred embodiments of the invention, by way of example, with reference being made to the accompanying drawings in which:

Figure 1 is a perspective view from the front of a first embodiment of the invention; Figure 2 is a perspective view from the front of a second embodiment of the invention; Figure 3 is a perspective view from behind of the embodiment of Figure 2; and Figures 4a and 4b show typical shafts onto which the components of Figures 1 to 3 may be secured.

Referring to the drawings, there is shown in Figure 1 a first embodiment of the invention. Figure 1 shows a component 10 in the form of a roller hub that is intended to be secured non rotatably on a circular shaft.

Component 10 includes a back wall 7 which is disc-like and an annular side wall 12 upstanding therefrom. One exemplary use for the component 10 shown in Figure 1 is for the outer peripheral surface 12a of the side wall 12 to engage e.g. a stack of paper sheets in a mailing machine for the purpose of withdrawing sheets.

Disposed centrally in back wall 11 is a generally circular, through going aperture 13. Aperture 13 includes aperture extensions 13a and 13b which are shaped like ears and extend aperture 13 into the back wall 11 on diametrically opposite sides of the circular part of aperture 13. Thus, the periphery of aperture 13 comprises two, oppositely disposed, almost semi-circular portions spaced from one another at each end by respective, ear-shaped aperture extensions 13a and 13b.

Projecting forwardly of aperture 13 (in the same direction that wall 12 is upstanding from base 11) are respective, arcuate, resiliently deformable members 14a and 14b. The members 14a and 14b are respectively secured on the substantially semi-circular portions of the periphery of aperture 13. The profiles of the members 14a and 14b correspond to the curvature of the arcuate portions of the periphery of aperture 13.

In the embodiment shown, the resiliently deformable members 14a and 14b extend forwardly to terminate in respective end surfaces 16a and 16b which are flush with the forwardmost (end) face 12b of the side wall 12.

The end surfaces 16a and 16b are substantially semi-circular when viewed in plan, in conformity with the arcuate portions of the periphery of aperture 13. The extreme ends of the surfaces 16a and 16b are provided with respective chamfers 17a, 17b, 17c and 17d. The chamfers extend inclinedly from the ends of the end surfaces 16a, 16b generally towards the rear of the component 10 as shown.

The chamfers 17 respectively terminate in edges a short distance from the respective ends of the end surfaces 16a and 16b. The arrangement is such that the chamfers are disposed opposite each other in pairs, ie. two chamfers 17a and 17c are disposed opposite one another at one end of the pair of end surfaces 16a, 16b and the other two chamfers 17b, 17d are disposed opposite one another at the other end of the end surfaces 16a and 16b.

A short gate surface 18 extends from the edges defined by each respective chamfer 17 towards the plane of the back wall 11. At the termini of the respective gate surfaces 18, the resiliently deformable members are undercut as indicated by the reference numerals 19. The undercuts 19 are arcuate and extend a short distance. The undercuts 19 merge into straight portions of the upright edges of the resiliently deformable members 14 which extend to the junctures of the respective members 14 with the periphery of the aperture 13.

Thus, it will be seen that the members 14 are spaced from one another on opposite sides of a circle defined by the aperture 13, with the chamfers 17 and gate surfaces 18 defining two pairs of jaws on opposite sides of such a circle.

In the region between the jaws and the periphery of aperture 13, the resiliently deformable members are spaced from one another to a greater extent than in the region of the jaws, by virtue of the undercuts 19.

The jaws are disposed on diametrically opposite sides of a circle defined by the aperture 13. There are additionally provided aligned with the jaws respective cups 20 formed in blocks 22 secured on the inner periphery of the side wall 12.

The cups are aligned with the jaws when viewed in plan. However, the bottoms 23 of the cups are in the embodiment shown disposed in a plane lying between the plane containing the jaws and the plane containing the back wall 11.

Referring now to Figures 4a and 4b, there are shown two typical elongate members which can be used in conjunction with components in accordance with the invention. In Figure 4a, there is shown a rigid, circular section shaft 24, such as a drive shaft. Drive shaft 24 includes a through going aperture in which is secured a cross pin 25.

It will readily be seen that, if the diameter of shaft 24 is less than the diameter of the circular portion of aperture 13 (and hence the aperture defined by the arcuate end surfaces 16a, 16b), one end of shaft 24 can be slideably inserted into the aperture defined by the arcuate end surface 16a, 16b and slid towards and out of aperture 13.

Such an action brings the cross pin 25 towards the end surfaces 16a, 16b of the members 14a, 14b.

When the cross pin 25 engages the ends of the members 14a, 14b, the cross pin 25 may come to rest on the chamfers 17a-17d as is desirable.

Alternatively, the cross pin 25 may come to rest on the end surfaces 16a, 16b. If the latter occurs, a short relative rotation between the component and the shaft 24 brings the cross pin to rest on the chamfers 17a-17d.

Continued progress of the shaft 24 through the aperture 13 is then prevented unless additional force is applied to the shaft 13 to cause it to continue sliding in the same direction. Such additional force presses the cross pin 25 into the chamfers 17a-17d with the result that the members 14a, 14b are spread apart. The cross pin 25 then passes between the gate surfaces 18 which are in contact with the cross pin 25 at this point. The cross pin 25 finally emerges into the undercut regions 19 of the members 14a, 14b.

Assuming that the cross pin 25 is of sufficient length, the ends of cross pin 25 will then abut the bottom surfaces 23 of the respective cups 20. Further-progress of the shaft 24 through the aperture 13 in the same direction is then prevented. It will thus be seen that by a simple, snap fit action, the shaft 24 bearing the cross pin 25 is retained rigidly relative to the component 10, because the bottom surfaces 23 of the cups 20 prevent movement of the cross pin (and hence the shaft) towards back wall 11, and the undercuts 19 prevent such movement away from the back wall 11.

The component 10 can be removed from the shaft 24 by firmly withdrawing the shaft away from back wall 11. This causes cross pin 25 to engage the undercuts 19, and spread the resiliently deformable members apart. The cross pin 25 then passes via the gate surfaces 18 to emerge at the chamfers 17, thereby freeing the shaft and component 10 relative to one another.

The members 14a, 14b can be arranged to flex in the regions between their ends 16a, 16b and their attachments to the periphery of aperture 13.

Alternatively, or in addition, flexing can be achieved by flexing of the back wall 11 relative to the remainder of the component 10. The aperture extensions 13a, 13b facilitate such flexing. In embodiments where such flexing of the back wall 11 is not required, the aperture extensions 13a, 13b can be dispensed with and the aperture 13 can be constructed as a circle.

Referring now to Figures 2 and 3, there is shown a second embodiment of the invention.

In this embodiment, the component 10 is constituted as a wheel having formed thereon peripheral vanes or projections 30. These may serve as anchorages for a rubber (or plastics) rim which is moulded onto the component.

The parts of the component 10 of Figures 2 and 3 that permit the securing of a shaft such as shaft 24 are functionally identical to their counterparts in the embodiment of Figure 1. The rear view shown in Figure 3 is useful for identifying the aperture extensions 13a and 13b, the gate surfaces 18 and the undercuts 19.

The component 10 shown in the drawings can take a great variety of forms, as previously mentioned. The components 10 can be manufactured from a great variety of suitable materials. However, it is important for the members 14a, 14b to be resiliently deformable to an appropriate degree.

This can be achieved through judicious choosing of: the materials of the members 14a, 14b; optionally the materials of the back wall 11; and also possibly the thickness of the members 14a, 14b and the back wall.

The embodiments shown herein are intended for non-rotatable securing on a shaft such as shaft 24 of Figure 4a. However, as an alternative, the components can readily be constructed as rotatable items, for example by manufacturing those parts of the component responsible for the securing function as an insert to be rotatably secured within the outer parts of the component such as side wall 12. This has been shown in an exemplary manner in the embodiment of Figure 1, wherein the line 26 denotes an optional division between the securing components and the side wall 12. A suitable bearing mechanism (e.g. a roller bearing) can be incorporated between the two resulting parts of the component 10.

As previously mentioned, the shaft on which the component 10 is to be secured can be manufactured in a variety of shapes and configurations.

A square section shaft 27 is shown in Figure 4b. Of course, when shaft is sections other than circular are employed, the aperture 13 needs to be shaped accordingly.

It should also be realised that the elongate member to which the component 10 is to be secured need not be straight, but can be curved or even angled.

Suitable materials for the component 10 include various plastics materials. If the component 10 is manufactured from a plastics material it can be readily be manufactured by a moulding process.

Alternatively, numerous metals could be used, or the component lo could be manufactured as a sintered part. Moreover, a single component 10 can be manufactured as a composite item from a variety of appropriate materials if desired.

A component in accordance with the invention readily allows the assembly of, e.g., machines having many small components mounted on shafts to be achieved more rapidly and economically.

8

Claims

1. A component adapted for securing relative to an elongate member, the component comprising:

an elongate aperture adapted to receive an elongate member; first and second resiliently deformable members extending in the longitudinal direction of the aperture and spaced from one another to define a pair of jaws; and an abutment spaced from the jaws in said longitudinal direction, the resiliently deformable members lying closer together in the vicinity of the j aws than in a further region spaced f rom the j aws such that, as the component and such an elongate member are moved one relative to the other, a protuberance secured on the elongate member may be advanced towards and forced between the jaws to lie in said further region of the resiliently deformable members, the abutment being so positioned that the protuberance is is engageable therewith when disposed in said further region thereby to limit or prevent further relative movement between the component and such an elongate member unless the protuberance is forced in the reverse direction out of the jaws.

2. A component according to Claim 1 wherein the aperture is generally circular.

3. A component according to Claim 1 or Claim 2 wherein the resiliently deformable members are secured on generally opposite sides of the aperture and extend from the aperture to define the jaws at a location spaced from the aperture.

4. A component according to any preceding claim wherein at least one of the resiliently def ormable members has a profile congruent with part of the periphery of the aperture, said resiliently deformable member being adapted to support the component on an elongate member inserted into the aperture.

5. A component according to any preceding claim, wherein the resiliently deformable members are secured to the component on the periphery of the aperture.

6. A component according to Claim 5, wherein the resiliently deformable members are additionally spaced from one another at their ends attached to the components, and wherein the aperture extends into the space or spaces between the resiliently deformable members.

7. A component according to any preceding claim, wherein the resiliently deformable members define two pairs of jaws, adapted to receive a corresponding pair of protuberances, and a corresponding pair of abutments.

8. A component according to any preceding claim wherein the or each abutment comprises a shoulder secured to the component and having formed therein a cup adapted to receive a protuberance.

9. A component according to any preceding claim wherein the or each abutment lies on a respective plane between the aperture and a corresponding pair of jaws.

is

10. A component according to any preceding claim adapted for securing on an elongate member in the form of a rigid shaft having at least one locating member extending laterally therefrom.

11. A component generally as herein described, with reference to or as illustrated in the accompanying drawings.

Amendments to the claims have been filed as follows CIAIMS 1. A component adapted f or securing relative to an elongate member, the component comprising:

an elongate aperture adapted to receive an elortgate member; first and second resiliently deformable members extending in the longitudinal direction of the aperture and spaced from one another to define a pair of jaws; and an abutment spaced from the jaws in said longitudinal direction, the resiliently deformable members lying closer together in the vicinity of the jaws than in a further region spaced from the jaws such that, as the component and such an elongate member are moved one relative to the other, a protuberance secured on the elongate member may be advanced towards and forced between the jaws to lie in said further region of the resiliently deformable members, the abutment being so positioned that the protuberance is is engageable therewith when disposed in said further region thereby to limit or prevent further relative movement between the component and such an elongate member unless the protuberance is forced in the reverse direction out of the jaws. wherein the resiliently deformable members are additionally spaced from one another at their ends attached to the components, and wherein the aperture extends into the space or spaces between the resiliently deformable members.

2. A component according to Claim 1 wherein the aperture is generally circular.

6. A component according to any preceding claim, wherein the resiliently 6. A component according to any preceding claim, wherein the resiliently deformable members define two pairs of jaws, adapted to receive a corresponding pair of protuberances, and a corresponding pair of abutments.

7. A component according to any preceding claim wherein the or each abutment comprises a shoulder secured to the component and having formed therein a cup adapted to receive a protuberance. 8. A component according to any preceding claim wherein the or each 10 abutment lies on a respective plane between the aperture and a corresponding pair of jaws. 9. A component according to any preceding claim adapted for securing an an elongate member in the form of a rigid shaft having at least one is locating member extending laterally therefrom.

10. A component according to any preceding claim including one or more peripheral projections adapted for the securing of e.g. a rim or tyre onto the component.