GB2326438A - Hose clamp - Google Patents

Abstract

A hose clamp 1 comprises a strip 10, a housing 12 mounted on one end of the strip 10, a driving member 18 mounted in the housing 12, in which a distal end 13 of the strip 10 passes through the housing 12 to form a loop. The driving member 18 comprises a flat face carrying teeth or threads (23, Fig 3) to engage slots or slits 15 in the strip 10. Rotation of the driving member 18 about an axis normal to the flat face causes expansion and contraction of the loop. The driving member 18 is slidable in the housing 12 between a first position in which the threads or teeth 23 engage the slits 15 to a second position in which the threads or teeth 23 are disengaged from the slits 15, and retaining means 32 are provided on a surface of the clamp 1 to retain in use the distal end 13 of the strip 10.

Description

IMPROVEMENT8 RELATING TO CLIP8 This invention relates to clips and especially to clips of the kind comprising a strip, one end of the strip being secured to a housing, the other end of the strip passing through the housing and a driving member mounted in the housing and engagable with slots or slits in the strip so that rotation of the driving member in one direction causes the loop to contract to grip anything placed within the loop and rotation in the other direction causes the loop to expand. Such clips are frequently used to secure hoses to pipes.

An example of such a clip is described in GB-1 551 041, wherein the driving member is a rotatable disc having a substantially flat face abutting the strip. The flat face carries teeth or threads which are so shaped that they engage the slots or slits in the strip and rotation of the driving member about an axis normal to the flat face causes expansion or contraction of the loop. The driving member is slidable in the housing between a first position in which the threads or teeth of the driving member engage the slots or slits in the strip and a second position in which the threads or teeth are disengaged from the slots or slits.

A disadvantage of clips such as those described in GB-1 551 041 is that the driving member is difficult to manufacture in metal or conventional plastics as the material forming process leads to tearing of the threads or teeth. A further disadvantage is that the strip and housing are manufactured as separate components. This leads to increased expense of manufacture. Yet another potential disadvantage is that once secured to a pipe or other fixture, the loose end of the strip could cause injury to the hands of a user since the end of the strip is often sharp and can protrude to a significant length from the housing. This has often led to users of such clips cutting off the loose end of the clip which renders the clip non-reusable.

It is therefore an object of the present invention to provide a clip having a strip and a housing as a single component. It is a further object of the present invention to provide a clip having a driving member that may be manufactured without the teeth or threads being subjected to tearing. It is a yet further object of the present invention to provide a clip wherein the loose end of the strip is securely and safely retained to thereby avoid injury to the hands of a user of the clip.

The present invention therefore provides a clip comprising a strip, a housing mounted on one end of the strip, a driving member mounted in the housing, in which a distal end of the strip passes through the housing to form a loop; the driving member comprising a substantially flat face abutting the strip, the flat face carrying teeth or threads to engage slots or slits in the strip and rotation of the driving member about an axis normal to the flat face causing expansion and contraction of the loop; the driving member being slidable in the housing between a first position in which the threads or teeth engage the slits and a second position in which the threads or teeth are disengaged from the slits; wherein retaining means are provided on a surface of the clip to retain in use the distal end of the strip.

An advantage of providing retaining means on the clip to secure the distal end once it has passed through the housing is that the distal end of the strip is not free to move away from the loop where it may easily cause injury to the hands of a user. Thus the temptation to remove the distal end of the strip once the clip has been tightened is reduced.

Preferably the retaining means comprise detents on a surface of the clip to retain in use the distal end of the strip; the detents being flexible to allow the strip to be engaged with and disengaged from the detents by flexing of the detents in response to movement of the distal end of the strip.

Preferably the driving member has, on its flat face, a single spiral thread in the manner of a scroll with the strip passing over the centre of the face and abutting the face only on one side of the centre of the face.

Preferably the driving member comprises a disc having the substantially flat face, and a shaft coupled to the disc, the shaft being slidable in a slot in the housing.

It is desired that the disc and the shaft are integral.

Preferably the shaft comprises means for rotating the shaft about an axis normal to the flat face.

In one embodiment the means for rotating the shaft comprises an indentation in an end of the shaft for receiving in use a screwdriver.

In another embodiment the means for rotating the shaft comprise flattened projections to allow rotation by hand.

Preferably the driving member comprises means for limiting the torque applied to the flat face of the driving member.

Preferably the torque limiting means comprise an overcap engagable with the shaft; the overcap comprising one or more internal teeth, each tooth having an inclined face and a substantially perpendicular face; the shaft having external teeth engagable with the internal teeth of the overcap; wherein rotation of the overcap in the direction corresponding to contraction of the loop urges the internal teeth of the overcap to move vertically relative to the external teeth of the shaft such that when the torque applied reaches a threshold level the teeth of the overcap and shaft move out of contact allowing the overcap to rotate freely relative to the shaft.

An advantage of limiting the torque applied to the clip is that over-tightening of the clip is prevented. This helps to prevent over-stretching of the clip, and in an extreme case the breaking of the clip due to the forces applied exceeding the strength of the strip or housing. Also it provides an easy means for tightening the clip to a known extent, simply be tightening the clip until the overcap and shaft rotationally disengage.

Preferably the overcap comprises a detent locatable in a recess in the shaft to retain said overcap on the shaft in use; the overcap further comprising two or more slots in a cylindrical portion of the overcap to allow an inwardly-directed flange of the overcap to be prised apart to allow the overcap to be engaged over the shaft.

It is desired that the strip and the housing are formed integrally.

Preferably the clip is made from glass-filled nylon.

Preferably the glass filled nylon is greater than 20% by weight glass.

Glass-filled nylon has material advantages in that it is more resistant to tearing and is more suitable for forming in certain processes e.g.

pressing. Furthermore, nylon is better than plastics as it can withstand higher temperatures, such as those which occur under the bonnet of a car.

A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1A is a side view of the clip; Figure 1B is a top plan view of the clip; Figure 2 is a side view of a part of the clip; Figure 3 is a cross-sectional view of the driving member; Figure 4 is a top plan view of the driving member; Figure 5 is a side view of the driving member; Figure 6 is a perspective view of a part of the clip; Figure 7 is a side view of another embodiment of the driving member; Figure 8 is a part cross-sectioned view of a part of the present invention; Figure 9 is a side elevation of a part of the present invention; Figure 10 is a top plan view of a part of the present invention.

Referring to Figures 1 to 10 of the drawings, a clip 1 according to the invention comprises a strip 10 having at one end a housing 12. On one face, the strip 10 has a plurality of slots or slits 15.

Hereinafter any reference to the term "slits" also includes the term "slots" and any similar shaped aperture. These slits 15 form teeth having a buttress form, i.e. they have one substantially perpendicular face 16, the other face 17 being inclined. In one embodiment, there are approximately 5.5 teeth per centimetre and the tooth depth is 1.14 millimetres.

Also mounted within the housing 12 is a driving member 18. Member 18 comprises a disc 19 having a flat face and a shaft 20. Preferably, the disc 19 and shaft 20 are formed as a single component to minimise the number of components and reduce manufacturing costs. Also the disc 19 and shaft 20 are less likely to break apart in use when formed as a single component, rather than two separate components joined, for example, by swaging. The shaft 20 has a head 21 having a screwdriver slot 22 therein.

On the flat face of the disc 19 is a spiral thread 23 bearing teeth having the same form as the slits 15.

The housing 12 has openings 24, 25 through which the strip 10 may pass. The housing 12 also has an open slot 26 at one end, which slot 26 receives the shaft 20 as shown in Figure 1B.

The clip 1 is assembled as shown in Figure 1A.

The disc 19, by virtue of the slot 26 receiving the shaft 20, can be moved between a position as shown in Figures 1A and 1B in which the threads 15 and 23 engage, and a position in which the disc lies at the leftmost part of the housing as viewed in Figure 1A and in the uppermost part of the housing as viewed in Figure 1B, the threads 15 and 23 being disengaged.

In use, the disc 19 is moved to a "disengaged" position and a distal end 13 of the strip 10, remote from the housing 12, is then curled and passed through opening 24 of the housing 12 in a "forward" direction, emerging through opening 25 of the housing 12, as shown in Figure 1A.

The loop so formed is then placed over the article which it is designed to clamp. This may, for example, be a piece of rubber hose which has been passed over a metal pipe.

The distal end 13 of the strip 10 is then pulled through the housing 12, until the loop closely embraces the article to be clamped.

The strip 10 also includes a pair of detents 32 as shown in Figures 1A and 6. The strip 10 may be engaged with the detents 32 by pressing the strip 10 down onto the detents 32 in a direction substantially perpendicular to the strip 10 adjacent the detents 32.

The engagement of the strip 10 with the detents 32 is accommodated by the detents 32 flexing outwardly (away from the centre-line of the strip 10) to allow the strip 10 to pass therebetween. The flexing movement of the detents 32 is encouraged by the provision of upper and lower ramped surfaces 35, 36 on the detents 32. The downward movement of the strip 10 whilst contacting the upper ramped surface 35 of the detents 32 causes the detents 32 to flex outwardly. Once the strip 10 has passed through the detents 32, the detents 32 flex back into their rest position, thus securely retaining the distal end 13 of the strip 10.

The distal end 13 of the strip 10 may be disengaged from the detents 32 by pulling on the distal end 13 with sufficient force to flex the detents 32, by means of the strip 10 contacting the lower ramped surfaces 36, to a point where the strip 10 may pass between the detents 32. Retaining the distal end 13 of the strip 10 close to the remainder of the strip 10 by retaining means such as the detents 32 helps to prevent injuries to the hands of a user, who might otherwise injure themselves on the loose, flapping end 13. The detents 32 also serve to retain the distal end 13 when the driving member 18 is disengaged from the strip 10.

Thus, the detents 32 restrict the movement of the strip 10 in a "rearward" direction through the housing 12 (in the direction from opening 25 towards opening 24) by means of engaging the distal end 13. The detents 32, however, allow the strip 10 to be manually fed through the housing 12.

The disc 10 is then moved into the position shown in Figures 1A and 1B in which the threads 23 engage the slits 15 and the loop can then be firmly tightened onto the article to be clamped by turning the disc 19 through the medium of the shaft 20 using a screwdriver inserted into the slot 22. The action of the vertical faces 16 of the slits 15 tends to hold the disc 19 in the position shown in Figure 1A.

When it is desired to release the clip 1, the distal end 13 of the strip 10 is disengaged from the detents 32 and the disc 19 is given a few turns in an opposite direction to slacken the loop and once a little play has been obtained, the disc 19 may be moved out of engagement with the strip 10 and the strip 10 may be manually pulled out of the housing 12 in the rearward direction.

The thread 23 on the disc 19 may be produced by a pressing operation, which is a relatively inexpensive operation compared with machining. The material of the clip 1 may be a metal or plastic. However, it has been found that the teeth on the disc 19 are difficult to form and have a tendency to tear during manufacture. To overcome this problem, it has been found that glass-filled nylon is a suitable material from which to form the disc 19, and also the remainder of the clip 1. Preferably, the nylon contains 20% to 30% glass by volume.

It is not necessary for the strip 10 to have slits 15 along its entire length. In the above example, the slits 15 extend for three to four centimetres along the strip 10. The overall length of the strip 10 is in the order of 100 to 125 millimetres.

The clip 1 of the present invention is not restricted to any particular size and may be manufactured to be suitable for use with pipes of a wide range of diameters.

With the clip 1 forming the subject of this example, the load which will be applied to the clip 1 by the screwdriver during tightening of the clip 1 will be substantially radial. With some known clips the force applied is tangential. The clip therefore tends to slip away from the screwdriver by rotating about the centre of the loop.

Instead of a screwdriver slot 22, the member 18 may be provided with a butterfly wing head 40 comprising flattened projections as shown in Figure 7.

This conveniently allows the clip 1 to be tightened and loosened by hand.

The driving member 18 may comprise a safety cap as shown in Figures 8, 9 and 10. The safety cap provides a means of preventing over-tightening of the clip 1. The safety cap comprises a female overcap 50 and a male shaft 51 formed as an extension of the shaft 20. The male shaft 51 is of larger diameter than the shaft 20, thereby forming a recess 56 between the male shaft 51 and disc 19. The overcap 50 and shaft 51 respectfully comprise internal and external teeth 52 and 53. The teeth 52 and 53 have a complimentary buttress form having a substantially perpendicular face 54, and another face 55 which is inclined.

The overcap 50 has a cylindrical section 60 below the internal teeth 52. The cylindrical section 60 comprises on the end furthest from the internal teeth 52 an inwardly-directed flange 57. Preferably, the inwardly-directed flange 57 extends around a substantial part of the circumference of the cylindrical section 60. The cylindrical section 60 also comprises two slots 58 on opposing sides of the cylindrical section 60 extending from the end furthest from the internal teeth 52 part way along the cylindrical section 60. The slots 58 allow the cylindrical section 60 to expand laterally in the direction perpendicular to the plane of the slots 58 when a prising force is applied to the cylindrical section 60. The overcap 50 is matingly engaged with the male shaft 51 by prising the cylindrical section 60 apart sufficiently to allow the inwardly-directed flange 57 to pass over the male shaft 51. With the overcap 50 in position and the prising force removed, the inwardly-directed flange 57 is free to flex back into the recess 56 beneath the male shaft 51. The inwardly-directed flange 57 acts to retain the overcap 50 on the male shaft 51.

With the overcap 50 engaged on the shaft 51 the overcap 50 is free to move vertically relative to the shaft 51 by a predetermined amount. The vertical movement of the overcap 50 is constrained at the upper limit by the inwardly-directed flange 57 striking the shaft 51 and at the lower limit by the internal and external teeth 52, 53 fully engaging. The overcap 50 comprises a screwdriver slot 22 on a horizontal face 21. In the rest position the overcap 50 will tend to be located such that the internal and external teeth 52, 53 are fully engaged.

In use, a user of the clip 1 tightens the driving member 18 by use of a screwdriver applied to the screwdriver slot 22. Initially, as the overcap 50 is turned in the clockwise sense, the shaft 51 and disc 19 are rotated together with the overcap 50. Once the slits 15 and threads 23 have been firmly engaged, the resistance to movement of the disc 19 increases.

Continued rotation of the overcap 50 leads to the inclined faces 55 of the teeth 52 and 53 sliding relative to one another, leading to the overcap 50 moving vertically upwards relative to the shaft 51.

Further rotation of the overcap 50 leads to the teeth 52 and 53 becoming vertically displaced relative to one another and thus disengaged allowing the overcap 50 to rotate whilst the shaft 51 and disc 19 remain stationary. In this way, the safety cap limits the amount of torque that can be applied to the disc 19 of the driving member 18 and hence, prevents the clip 1 being over-tightened.

The perpendicular faces 54 of the teeth 52 and 53 do not limit the amount of torque that can be applied in the counter-clockwise sense in order to loosen the clip 1.

The screwdriver slot 22 of the overcap 50 may be replaced by a butterfly head as described above.

Claims (15)

CLAIMB:-

1. A clip comprising a strip, a housing mounted on one end of the strip, a driving member mounted in the housing, in which a distal end of the strip passes through the housing to form a loop; the driving member comprising a substantially flat face abutting the strip, the flat face carrying teeth or threads to engage slots or slits in the strip and rotation of the driving member about an axis normal to the flat face causing expansion and contraction of the loop; the driving member being slidable in the housing between a first position in which the threads or teeth engage the slits and a second position in which the threads or teeth are disengaged from the slits; wherein retaining means are provided on a surface of the clip to retain in use the distal end of the strip.

2. A clip as claimed in claim 1 wherein the retaining means comprise detents on a surface of the clip to retain in use the distal end of the strip; the detents being flexible to allow the strip to be engaged with and disengaged from the detents by flexing of the detents in response to movement of the distal end of the strip.

3. A clip as claimed in claim 1 or claim 2, wherein the driving member has, on its flat face, a single spiral thread in the manner of a scroll with the strip passing over the centre of the face and abutting the face only on one side of the centre of the face.

4. A clip as claimed in any preceding claim wherein the driving member comprises a disc having the substantially flat face, and a shaft coupled to the disc, the shaft being slidable in a slot in the housing.

5. A clip as claimed in claim 4 wherein the disc and the shaft are integral.

6. A clip as claimed in claim 5 or claim 6 wherein the shaft comprises means for rotating the shaft about an axis normal to the flat face.

7. A clip as claimed in claim 6 wherein the means for rotating the shaft comprises an indentation in an end of the shaft for receiving in use a screwdriver.

8. A clip as claimed in claim 6 wherein the means for rotating the shaft comprise flattened projections to allow rotation by hand.

9. A clip as claimed in any preceding claim, wherein the driving member comprises means for limiting the torque applied to the flat face of the driving member.

10. A clip as claimed in claim 9, wherein the torque limiting means comprise an overcap engagable with the shaft; the overcap comprising one or more internal teeth, each tooth having an inclined face and a substantially perpendicular face; the shaft having external teeth engagable with the internal teeth of the overcap; wherein rotation of the overcap in the direction corresponding to contraction of the loop urges the teeth of the overcap to move vertically relative to the teeth of the shaft such that when the torque applied reaches a threshold level the teeth of the overcap and shaft move out of contact allowing the overcap to rotate freely relative to the shaft.

11. A clip as claimed in claim 10 wherein the overcap comprises an inwardly-directed flange locatable in a recess below the shaft to retain said overcap on the shaft in use; the overcap further comprising two or more slots in a cylindrical section of the overcap to allow the inwardly-directed flange of the overcap to be prised apart to allow the overcap to be engaged over the shaft.

12. A clip as claimed in any preceding claim wherein the strip and the housing are formed integrally.

13. A clip as claimed in any preceding claim, wherein the clip is made from glass-filled nylon.

14. A clip as claimed in claim 13, wherein the glass filled nylon is greater than 20% by weight of glass.

15. A clip substantially as hereinbefore described with reference to and as shown in the accompanying drawings.