GB2447487A - Hose clamping arrangements - Google Patents

Abstract

A hose clamp 10 of the type in which a flexible band 12 provided with teeth 32 extends from a head 14 and is passed back for the teeth to be engaged by locking means within the head has an inwardly projecting formation 36 on a clamping surface of the band to engage a cylindrical clamping surface 48 of a hose 44. The surface 48 is preferably defined between annular ridges 52. Alternatively the clamping surface 48 of the hose can have an outwardly-protruding formation which engages a cylindrical clamping surface of the band 12. This formation can be either integral with the hose or be formed on an insert located in a depression in the hose clamping surface 48. The projecting formations are narrower than the clamping surfaces an concentrate the clamping force.

Description

IMPROVEMENTS RELATING TO HOSE CLAMPS

The invention relates to a hose clamp suitable for clamping a hose to a cooperating male boss in a low to medium pressure device such as an air intake system in a vehicle The invention also relates to hose assemblies which comprise a hose and a hose clamp, and to modified hoses suitable for use in such assemblies In particular, the invention further relates to a hose clamp suitable for low to medium pressure devices such as are common in a vehicle and further relates to a method of manufacturing a vehicle involving use of a hose assembly It is common in the automotive industry to secure a flexible hose to a male portion or boss of a component, which expression encompasses a comparatively rigid tubular structure over which a hose must be secured, using a band clamp. For example, band clamps are often used to secure flexible hoses such as breather hose' between male bosses on an air filter and a throttle body in a vehicle engine air intake system.

A band clamp typically comprises a metallic band attached at one end to a housing supporting a threaded screw. The other end of the band can be fed through the housing to form a loop for encircling a hose The band usually has a plurality of slots or grooves which engage the screw thread to form a worm drive for tightening the band around the hose when the screw is turned in the housing.

Breather hoses are used in may automotive applications including throttle bodies as described hereinafter. When a breather hose is installed on a vehicle production line, the ends of the hose are typically fitted over the respective male bosses on the air filter and throttle body, and band clamps are placed around each end of the hose and tightened using a screwdriver or similar tool to clamp the hose around the male bosses.

The band clamp described above can be problematic to fit on a fast-moving vehicle assembly line in the short period of time in which it must be fitted. This is because such band clamps have a tendency to bind-up and jam when torque is applied to the screw.

In addition, engaging the screwdriver or other tool with the screw can be awkward, and may result in the head of the screw being damaged Furthermore, over-tightening the screw can damage the band clamp If a band clamp is damaged during fitting of the hose, then the entire section of hose is usually discarded because there is often not time to remove a damaged band clamp from the hose. This can lead to a considerable wastage of parts and money As well as being problematic to fit, band clamps are relatively expensive. A spring clamp is one example of an alternative type of hose clamp that is generally cheaper than a band clamp However, in common with most other cheaper clamping solutions, spring clamps may be incapable of producing the clamping forces sufficient to secure a hose.

It is therefore an object of the invention to provide a low-cost solution for quickly and easily securing a hose to a male portion of a component, which overcomes the various problems described above, and which is suitable for use in low-pressure and medium-pressure applications.

According to the present invention there is provided a hose clamp comprising: a flexible band having a proximal end and a free distal end; a locking head at the proximal end of the band, the locking head having a passage into one end of which the distal end of the band may be inserted to the extent that the distal end protrudes from the other end of the passage, the band thereby forming a loop that can be tightened by gripping and pulling the protruding distal end away from the locking head, the locking head then being co-operable with the band to lock the loop in a tightened condition; wherein a first surface of the band has at least one inwardly-protruding formation, the first surface being innermost when the band is formed into the loop, the formation defining a contact area that is smaller than the area of the first surface and through which, in use, increases clamping pressure is exerted on a hose By means of the invention, the hose clamp can be installed easily around the hose and tightened by hand without requiring tools This means that the hose clamp can be fitted quickly and reliably on the production line, resulting in an increase in efficiency.

The or each inwardly-protruding formation may be regarded as a means for uniformly reducing the contact area between the hose clamp and the hose, thereby resulting in an increased clamping pressure on the hose The hose clamp can provide an adequate clamping pressure when made from a plastics material such as nylon, which is relatively inexpensive. Increasing the clamping pressure produced by the loop for any given tension in the band raises the potential clamping capacity for any given cross section of the band prior to reaching the axial yield load for the band material.

The or each inwardly-protruding formation may be integrally formed with the hose clamp, and the locking head and the band may be parts of a single moulding. The band may have opposed longitudinal edges and the or each inwardly-protruding formation may be disposed between those edges. In embodiments to be described, the or each inwardly-protruding formation is arranged in the form of a substantially continuous rib or ridge which extends around the inner circumference of the loop The substantially continuous rib ensures that an even seal is provided between the hose and the male coupling member. Where the rib projects to a substantially uniform extent from the first surface of the band along at least a majority of the length of the band, this ensures that the clamping pressure exerted by the hose clamp is substantially even around the circumference of the loop The band may have at least one locking formation that, as the band advances through the passage, is engageable with a pawl associated with the locking head to lock the loop in the tightened condition. The hose clamp may have a plurality of locking formations spaced along its length to allow the loop to be locked in a plurality of tightened conditions, so that the hose clamp can be used to clamp hoses of varying diameter The or each locking formation is suitably co-operable with the pawl in a ratchet arrangement for allowing the band to advance through the passage to narrow the loop, but resisting withdrawal of the band from the passage to widen the loop. A ratchet arrangement facilitates fitting of the hose clamp because the loop is locked in the tightened conditioned automatically when the band is pulled through the passage; this enables the hose clamp to be both tightened and locked in one swift action. As an alternative to an automatic locking arrangement, the locking head may be manually operable to lock the loop when in the tightened state For example, the hose clamp may include a locking ball which is moved forward and rearward to lock the loop in the tightened condition The locking formations may be on a second surface of the band which is outermost when the band is formed into the loop. In such an arrangement, the locking formations are on the opposite side of the band to the or each inwardly-protruding formation which provide the reduced contact area with the hose. This arrangement enables the locking means and the contact area-reducing means to be optimized independently of one another. In an embodiment of the invention to be described, the band of the hose clamp includes a series of teeth on the outermost surface, and a rib on the innermost surface. If, for example, the teeth and the rib were both provided on the innermost surface, the ratchet pawl would have to negotiate the rib when engaging the teeth, and this would result in a reduced area of contact between the ratchet pawl and the teeth and hence a reduced maximum clamping force.

The inventive concept encompasses a hose which is suitable for being clamped to the male coupling member using the hose clamp of the invention as defined above. The hose comprises an end portion defining an opening for receiving a male coupling member; and a cylindrical clamping surface extending around the end portion and being co-operable with a band of an encircling hose clamp; wherein the clamping surface is defined between annular ridges spaced along and protruding from the end portion.

The means for reducing the contact area between the hose and the hose clamp need not be associated with the hose clamp. For example, the inventive concept extends to a hose having outwardly protruding formations on an outer surface for reducing the contact area between the hose and a hose clamp. The hose has an end portion defining an opening for receiving a male coupling member, and a cylindrical clamping surface extending around the end portion and being co-operable with a band of an encircling hose clamp; wherein the clamping surface has at least one outwardly-protruding formation defining a contact area that is smaller than the area of the clamping surface and through which, in use, clamping pressure from the hose clamp is exerted on the hose The or each outwardly protruding formation may be a substantially continuous rib extending around the outer circumference of the clamping surface. For optimally distributed clamping pressure, the rib may project to a substantially uniform extent from the clamping surface along at least a majority of the circumference of the clamping surface. The clamping surface may be defined between annular ridges spaced along and protruding from the end portion. The or each outwardly-protruding formation may be disposed on the clamping surface between said ridges. The or each outwardly-protruding formation may protrude from the clamping surface to a lesser extent than the ridges protrude from the end portion.

The inventive concept also encompasses a hose arrangement in which the means for reducing contact area is separate from both the hose clamp and the hose. The hose assembly comprises a hose having an end portion defining an opening for receiving a male coupling member, and a cylindrical clamping surface extending around the end portion and being co-operable with a band of an encircling hose clamp, wherein the clamping surface includes at least one recessed seat for retaining a member that then protrudes from the clamping surface to define a contact area that is smaller than the area of the clamping surface and through which, in use, clamping pressure from the hose clamp is exerted on the hose. The member may be an 0-ring which protrudes from the clamping surface to provide the reduced contact area between the hose clamp and the hose The inventive concept extends to a hose assembly comprising the hose clamp of the invention as defined above, and a hose suitable for being clamped to a male coupling member using the hose clamp. In this assembly, therefore, the means for reducing the contact area between the hose clamp and the hose is associated the hose clamp. The hose comprises an end portion defining an opening for receiving a male coupling member A cylindrical clamping surface extends around the end portion and is co-operable with the encircling band of the hose clamp such that the inwardly-protruding formation of the hose clamp bears against the clamping surface to press the hose against the male coupling member in use.

The inventive concept further extends to a hose assembly in which the contact area reducing means is associated with the hose instead of with the hose clamp. The hose therefore includes either outwardly protruding formations as described above, or a recessed seat, also as described above, for retaining a member such as an 0-ring which provides the means for reducing the contact area. In this case, the hose clamp comprises a flexible band that may be formed into a loop encircling the clamping surface of the hose, wherein, in use, the outwardly-protruding formation on the hose, or the outwardly protruding member seated in the recessed seat in the clamping surface of the hose, bears against a first surface of the band that is innermost when the band is formed into the loop, thereby defining said contact area through which clamping pressure is exerted on the hose.

As described, the inventive concept encompasses embodiments in which the means for reducing the contact area between the hose and the hose clamp is associated with the hose clamp, or with the hose, or is a separate component. As such, the inventive concept extends to a hose assembly comprising a hose and a hose clamp, wherein the hose clamp comprises: a flexible band having a proximal end and a free distal end; and a locking head at the proximal end of the band, the locking head having a passage into one end of which the distal end of the band may be inserted to the extent that the distal end protrudes from the other end of the passage, the band thereby forming a ioop that can be tightened by gripping and pulling the protruding distal end away from the locking head, the locking head then being co-operable with the band to lock the loop in a tightened condition; wherein the hose comprises: an end portion defining an opening for receiving a male coupling member, and a cylindrical clamping surface extending around the end portion and being co-operable with the encircling band of the hose clamp; and wherein at least one formation or member between an inner surface of the band and the clamping surface of the hose defines a contact area that is smaller than the area of the inner surface or the clamping surface and through which, in use, clamping pressure is exerted by the band on the hose. In this assembly, the or each formation or member between the inner surface of the band and the clamping surface may be inwardly protruding formations associated with the hose clamp such as those described above with reference to the hose clamp of the invention.

Alternatively, the or each formation or member may be outwardly protruding formations associated with the hose such as the outwardly protruding members described above.

As a further alternative, the or each formation or member may be a separate component, which is not part of the hose clamp or hose, but which is located therebetween. This separate component may, for example, be an 0-ring located around the clamping surface. The hose may include a recessed seat in the clamping surface for retaining the separate component in position.

The inventive concept also encompasses a method of clamping an end portion of a hose to a male coupling member of a vehicle component using a hose clamp, the hose clamp comprising a band, and the method comprising: forming the band into a loop around the end portion of the hose; tightening the loop around the end portion by pulling an end of the band, and locking the loop in a tightened condition to clamp the hose to the male coupling member. The method enables a hose to be secured to a male coupling member quickly and efficiently and does not require tools to tighten the hose clamp The method is suited to use in securing a breather hose between an air filter and a throttle body on a fast-moving vehicle production line.

The locking of the loop may take place automatically upon pulling the loop into the tightened condition.

The band may be passed around the end portion of the hose to form the loop after said end portion has been fitted to the male coupling member. Alternatively, the band may be formed into a loop, and the loop located around the end portion of the hose before the end portion is fitted to the male coupling member; the loop being tightened once the hose is fitted to the male coupling member.

It should be appreciated that subsidiary features of the invention, which are described in detail with reference to a particular embodiment but which, for brevity, may not be described again with reference to other embodiments, may have equal application to the other embodiments, and as such these subsidiary features may be interchanged between embodiments within the general ambit of the invention.

In order that the invention may be more readily understood, reference will now be made by way of example to the accompanying drawings in which: Figures la to if show views of a hose clamp having an integral rib according to a first embodiment of the invention; Figure 2 is an exploded schematic perspective view of a hose, the hose clamp of Figure 1, and a male boss; Figure 3 is a schematic section through the hose, the hose clamp and the male boss taken along the line A-A in Figure 2 with the hose clamped to the male boss; Figure 4 is an exploded schematic perspective view of a hose, a hose clamp, and a male boss, in which, in accordance with a second embodiment of the invention, a rib is integral with the hose instead of with the hose clamp, Figure 5 is a schematic section through the hose, the hose clamp, and the male boss taken along the line B-B in Figure 4 with the hose clamped to the male boss; Figure 6 is an enlarged detailed view of the hose in Figure 5, and Figure 7 shows schematic cross-sections of ribs having (a) part-circular, and (b) rectangular cross-sections, in each case showing the rib in (i) uncompressed and (ii) compressed forms.

Figures ia, lb and ic show a hose clamp 10 in accordance with a first embodiment of the invention. Figure la shows an example of the present invention prior to being formed into a loop The hose clamp 10 comprises an elongate flexible band 12 which is integral with a locking head 14 The band 12 and the locking head 14 are injection moulded in plastics material such as nylon, EFTE, ECFTE or other suitable polymeric material. The band 12 has proximal and distal ends 16, 18, with respect to the locking head 14; specifically, the band 12 extends from the locking head 14 at the proximal end 16 to the free, distal end 18 The locking head 14 comprises a band-receiving passage having an entrance 22 in a first side 24 of the locking head 14 and an exit 26 in a second side 28 of the locking head 14 (best seen in Figure ib). The distal end 18 of the band 12 is inserted into the entrance 22 of the passage 20, and protrudes from the exit 26 of the passage 20, the band 12 thereby forming a substantially circular loop 30 as shown in Figures lb and lc.

The band 12 comprises a plurality of teeth 32 (not shown in Figure ic) moulded into a surface 34 which is outermost when the band 12 is formed into the loop 30, the teeth 32 are equally spaced around the outer periphery of the loop 30 The teeth 32 are shown schematically in Figures 1 to 3. In reality, there will be many more teeth 32 than the number illustrated in the Figures. A pawl (not shown) is located within, and is integral with, the locking head 14. The pawl engages the teeth 32 to form a ratchet arrangement.

The ratchet arrangement allows the distal end 18 of the band 12 to pass through the passage 20 in one direction only i.e. to reduce the diameter of the loop 30, and hence to tighten the hose clamp 10. The pawl prevents the band 12 from passing back through the passage 20 in the reverse direction i.e. to loosen the hose clamp 10 A rib 36 protrudes from a surface 38 of the band 12 which is innermost when the loop 30 is formed. The innermost surface 38 and the outermost surface 34 are on opposite sides of the band 12, and hence the rib 36 is on the opposite side of the band 12 to the teeth 32. The rib 36 is shown in Figures 1 to 3. The rib 36 extends longitudinally along the length of the band 12, and is located substantially centrally between the parallel edges 40 of the band 12. The rib 36 is continuous along its length, and projects from the band 12 to a uniform extent along the length of the band 12. This continuous formation ensures that an even pressure is provided around the hose resulting in a seal. In alternative examples (not shown) the band 12 may be non-continuous although the integrity of the seal would have to be insured by other means. As shown in Figures lb and ic, when the distal end 18 of the band 12 is fed through the band-receiving passage of the locking head 14 to form the loop 30, the rib 36 extends around the inner circumference of the loop 30 and protrudes radially inwards.

Figures le and if show a fill-piece 43. In order to minimize the step 42 in the loop 30 where the band 12 enters the locking head 14, fill-piece 43 may be provided to maintain an even clamping pressure on the hose 44. The effect of this is that the innermost surface 38 of the band 12 is substantially continuous, and hence the hose clamp 10 is able to provide a substantially even clamping pressure on a hose 44 (Figure 2) around the circumference of the loop 30.

Figure 2 is an exploded schematic perspective view showing the hose clamp 10 of Figure 1 a portion of a hose 44, and a male boss 46 onto which the hose 44 is fitted.

The hose 44 is a rubber breather hose and the male boss 46 defines an air filter outlet [not shown] The hose 44 comprises a parallel-sided, tubular end portion 48 defining an opening 50 for receiving the male boss 46 in male-female relation. The hose 44 may have one or more other outlets or ends which are similarly arranged for connection to other components, for example, another end of the hose 44 may be arranged for connection to a throttle body.

The end portion 48 of the hose 44 comprises a pair of outwardly-protruding annular ridges 52 which are spaced from each other along the end portion 48 in parallel planes to define a cylindrical clamping surface 54 which extends around the end portion 48. The hose clamp 10 is received around the cylindrical clamping surface 54, between the annular ridges 52 which serve to retain the hose clamp 10 in position and substantially prevent it from sliding longitudinally.

Pre-fit assembly involves fixing the hose 44 to the male boss 46 is to feed the distal end 18 of the band 12 through the passage 20 in the locking head 14 to form a wide loop that is placed loosely around the end portion 48 of the hose 44 before the hose 44 is fitted over the male boss 46. Once the end portion 48 of the hose 44 has been fitted to the male boss 46, the hose clamp 10 is tightened around the clamping surface 54 of the hose 44 by gripping and pulling the distal end 18 of the band 12 as described above.

There are two ways to fix the hose 44 to the male boss 46 using the hose clamp 10, called hereinafter a pre-fit assembly and a post-fit installation. In the post fit installation the end portion 48 of the hose 44 is fitted over the male boss 46 and then to form the loop 30 of the hose clamp 10 by passing the band 12 around the clamping surface 54 of the hose 44 such that the innermost surface 38 of the band 12 faces the clamping surface 54. The distal end 18 of the band 12 is fed through the passage 20 in the locking head 14 of the hose clamp 10 to the extent that it protrudes from the exit 26 of the passage 20 in the locking head 14. The protruding distal end 18 is then gripped and pulled by hand in a direction away from the locking head 14, which causes the distal end 18 to advance further through the passage 20 and the band 12 to tighten around the clamping surface 54 of the hose 44.

As the band 12 is pulled through the passage 20 in the locking head 14, the pawl (not shown) in the locking head 14 rides over the teeth 32 on the band 12 until the band 12 is tightened sufficiently to prevent leaks or adequately secured and cannot be pulled any further through the passage 20 The ratchet arrangement locks the hose clamp 10 in this tightened position and prevents the hose clamp 10 from loosening The innermost surface 38 of the band 12 faces the clamping surface 54 of the hose 44 such that the rib 36 of the hose clamp 10 is in contact with the clamping surface 54 of the hose 44. The innermost surface 38 of the band 12 and the outer surface 56 of the rib 36 are smooth in order to reduce the friction between the band 12 and the clamping surface 54 when the hose clamp 10 is tightened, thereby allowing the band 12 to slide easily over the clamping surface 52 so minimising the force required to tighten the band 12 and so that local distortion of the hose 44 is reduced. Whilst the rib 36 presents little resistance to relative circumferential movement between the innermost surface 38 of the band 12 and the clamping surface 52 of the hose 44 as the band 12 is tightened, the rib 36 does however resist relative axial movement of the hose clamp 10 and the clamping surface 52 along the length of the hose 44, thus resisting axial creep Figure 3 is a schematic section through the hose 44, the hose clamp 10 and the male boss 46 taken along the line A-A in Figure 2 with the hose 44 clamped to the male boss 46 with the hose clamp 10 The rib 36 on the hose clamp 10 serves as a stress raiser' and concentrates the clamping force provided by the hose clamp 10 over a reduced area (i.e. substantially the area of the rib 36 as opposed to the area of the innermost surface 38 of the band 12), thereby increasing the clamping pressure on the hose 44. The increased clamping pressure causes the rib 36 to protrude into, and locally deform, the clamping surface 52 of the hose 44 as shown in Figure 3. The increased clamping pressure is translated through the clamping surface 52 of the hose 44, and bears down on the male boss 46 in a localised zone 58 of increased clamping pressure The increased clamping pressure in the zone 58 ensures that the hose 44 is clamped firmly to the male boss 46 in a manner that minimises leaks Referring now to Figure 4, this shows a second embodiment of the invention in which reference numerals incremented by 100 are used to denote features that are similar to those of the first embodiment. In the second embodiment, a circumferential rib 136 is integral with the hose 144 instead of with the hose clamp 110. Thus, in this embodiment, the innermost surface 138 of the band 112 is plain and uninterrupted by a rib, The circumferential rib 136 is located substantially equidistant from, or midway between the annular ridges 152 which define the cylindrical clamping surface 154 of the hose 144, and protrudes radially outwards from said clamping surface 154. The circumferential rib 136 is continuous around its circumference, and in this embodiment is integrally moulded with the hose 144 during manufacture.

Figure 5 is a schematic section through the hose 144, the hose clamp 110, and the male boss 146 taken along the line B-B in Figure 4, with the hose 144 clamped to the male boss 146 with the hose clamp 110. As with the first embodiment, the circumferential rib 136 serves as a stress raiser' and concentrates the clamping force provided by the hose clamp 110 over a reduced area (i.e. substantially the area of the circumferential rib 136 as opposed to the area of the innermost surface 138 of the band 112), thereby increasing the clamping pressure on the hose 144. The increased clamping pressure causes the circumferential rib 136 to deform slightly. In common with the first embodiment, the increased clamping pressure is translated through the clamping surface 154, and bears down on the male boss 146 in a zone 158 of increased clamping pressure The increased clamping pressure in the zone 158 ensures that the hose 144 is clamped firmly to the male boss In the enlarged view of Figure 6, it can be seen that the annular ridges 152 defining the clamping surface 154 of the hose 144 protrude from the hose 144 to a greater extent than the circumferential rib 136, so that when tightened, the hose clamp 110 (Figure 4 and 5)is between the annular ridges 152, and hence is retained longitudinally by said ridges 152. An additional advantage of the hose 144 having relatively high ridges 152 is that they assist in the initial positioning of the hose clamp 110 on the hose 144.

As before, the hose 144 may have one or more other outlets bosses or junctions also having integral circumferential ribs, so that the hose 144 can be clamped to other components in a similar manner.

The inventive concept also encompasses a hose arrangement in which the rib is a separate component, that is, which is not integral with a hose or with a hose clamp Whether the rib 36, 136 is a separate component, or is integral with the hose 44, 144 or with the hose clamp 10, 110, the function of the rib 36, 136 is the same; i e. to reduce the contact areabetween the hose 44, 144 and the hose clamp 10, 110, and thereby raise the clamping pressure on the hose 44, 144 provided by the hose clamp 10, 110. The contact area, and hence the clamping pressure are affected by the cross-section of the rib 36, 136, as will now be explained.

Whilst the embodiments shown in Figures 1 to 6 have ribs 36, 136 with part-circular cross-sections, in other embodiments the ribs 36, 136 may have otherwise rounded cross-sections, or cross-sections that define edges. For instance, Figure 7 shows schematic cross-sectional views of similarly sized ribs having (a) part-circular, and (b) rectangular cross-sections, in each case showing the rib in (i) uncompressed and (ii) compressed forms The skilled man would readily understand that other cross sectional profiles, e.g. triangular, are also possible within the scope of the invention. The shaded regions in Figure 7 represent the reduced contact area provided by the rib. Whereas a part-circular rib (Figure 7(a)) provides a contact area 160 which is defined by a convex surface 162 of the rib, a rectangular rib (Figure 7(b)) provides a contact area 164 which is defined by a substantially flat surface 166 of the rib. The contact area 160 of the part-circular rib (Figure 7(a)) is smaller than the contact area 164 of the similarly sized rectangular rib (Figure 7(b)), and hence the part-circular rib (Figure 7(a)) produces greater stress, and hence increased clamping pressure.

Figure 7(a) shows that whilst part-circular ribs have an advantageously small contact area 160 when uncompressed (Figure 7(a)(i)), they have a tendency to squash and flatten out when subjected to a clamping force (Figure 7(a)(ii)). If a part-circular rib flattens, the contact area 160 between the hose 44, 144 and the hose clamp 10, 110 increases, and hence the clamping pressure is reduced. As shown in Figure 7(b), rectangular ribs do not suffer from this problem to the same extent because, even though they may squash slightly when subjected to a clamping force, the contact area 164 does not increase as much as with part-circular ribs (Figure 7(a)), and hence the clamping pressure does not decrease by as much. With careful selection of materials and geometry, any detrimental effects on the clamping pressure brought about by deformation can be minimised.

Claims (38)

1. A hose clamp, comprising: a flexible band having a proximal end and a free distal end; a locking head at the proximal end of the band, the locking head having a passage into one end of which the distal end of the band may be inserted to the extent that the distal end protrudes from the other end of the passage, the band thereby forming a loop that can be tightened by gripping and pulling the protruding distal end away from the locking head, the locking head then being co-operable with the band to lock the loop in a tightened condition; wherein a first surface of the band has at least one inwardly-protruding formation, the first surface being innermost when the band is formed into the loop, the formation defining a contact area that is smaller than the area of the first surface and through which, in use, clamping pressure is exerted on a hose.

2. The hose clamp of Claim 1, wherein the or each inwardly-protruding formation is integrally formed with the hose clamp.

3. The hose clamp of Claim 1 or Claim 2, wherein the band and the locking head are parts of a single moulding.

4. The hose clamp of any preceding claim, wherein the band has at least one locking formation that, as the band advances through the passage, is engageable with a pawl associated with the locking head to lock the loop in the tightened condition.

5. The hose clamp of Claim 4, wherein the band has a plurality of locking formations spaced along its length.

6. The hose clamp of Claim 4 or Claim 5, wherein the or each locking formation is on a second surface of the band, the second surface being outermost when the band is formed into said loop

7 The hose clamp of any of Claims 4 to 6, wherein the or each locking formation is co- operable with the pawl in a ratchet arrangement for allowing the band to advance through the passage to narrow the loop, but resisting the withdrawal of the band from the passage to widen the loop.

8. The hose clamp of any preceding claim, wherein the locking head is co-operable with the band to lock the loop automatically in the tightened condition.

9 The hose clamp of any of Claims 1 to 7, wherein the locking head is manually operable to lock the loop when in the tightened state.

10. The hose clamp of any preceding claim, wherein the or each inwardly-protruding formation is a substantially continuous rib extending around the inner circumference of the loop.

11. The hose clamp of Claim 10, wherein the rib projects to a substantially uniform extent from the first surface along at least a majority of the length of the band

12. The hose clamp of any of Claims 1 to 10, wherein the rib tapers toward the locking head at the proximal end of the band.

13 The hose clamp of any of Claims 11 to 12, wherein the rib has a cross-section shaped to present a convex surface that defines the contact area

14. The hose clamp of any of Claims 11 to 12, wherein the rib has a cross-section shaped to present a substantially flat surface that defines the contact area.

15. The hose clamp of any of Claims 10 to 14, wherein the band has opposed longitudinal edges and the or each inwardly-protruding formation is disposed substantially centrally between those edges.

16. A hose, comprising: an end portion defining an opening for receiving a male coupling member, and a cylindrical clamping surface extending around the end portion and being co-operable with a band of an encircling hose clamp; wherein the clamping surface is defined between annular ridges spaced along and protruding from the end portion.

17. A hose, comprising an end portion defining an opening for receiving a male coupling member, and a cylindrical clamping surface extending around the end portion and being co-operable with a band of an encircling hose clamp; wherein the clamping surface has at least one outwardly-protruding formation defining a contact area that is smaller than the area of the clamping surface and through which, in use, clamping pressure from the hose clamp is exerted on the hose.

18. The hose of Claim 18, wherein the or each outwardly-protruding formation is a substantially continuous rib extending around the outer circumference of the clamping surface.

19. The hose of Claim 19, wherein the rib projects to a substantially uniform extent from the clamping surface along at least a majority of the circumference of the clamping surface.

20. The hose of Claim 19 or Claim 20, wherein the rib has a cross-section shaped to present a convex surface that defines the contact area.

21. The hose of Claim 19 or Claim 20, wherein the rib has a cross-section shaped to present a substantially flat surface that defines the contact area.

22. The hose of any of Claims 18 to 21, wherein the clamping surface is defined between annular ridges spaced along and protruding from the end portion, and the or each outwardly-protruding formation is disposed on the clamping surface between said ridges, and wherein the or each outwardly-protruding formation protrudes from the clamping surface to a lesser extent than the ridges protrude from the end portion

23. The hose of Claim 22, wherein the or each outwardly-protruding formation is substantially equidistant from each of the ridges.

24 A hose, comprising: an end portion defining an opening for receiving a male coupling member; and a cylindrical clamping surface extending around the end portion and being co-operable with a band of an encircling hose clamp; wherein the clamping surface includes at least one recessed seat for retaining a member that then protrudes from the clamping surface to define a contact area that is smaller than the area of the clamping surface and through which, in use, clamping pressure from the hose clamp is exerted on the hose.

25. The hose of Claim 24, wherein the clamping surface is defined between annular ridges spaced along and protruding from the end portion and the or each recessed seat is defined in the clamping surface between the ridges.

26. The hose of Claim 24, wherein the or each recessed seat is substantially equidistant from each of the ridges.

27. A hose as defined in any of Claims 17 to 26 and being a breather hose for a vehicle engine.

28. A hose as defined in any of Claims 17 to 27 and having a plurality of end portions each having a clamping surface as defined therein.

29. A hose assembly comprising a hose clamp as defined in any of Claims 1 to 16 and a hose, the hose comprising an end portion defining an opening for receiving a male coupling member, and a cylindrical clamping surface extending around the end portion and being co-operable with the encircling band of the hose clamp such that the inwardly-protruding formation of the hose clamp bears against the clamping surface to press the hose against the male coupling member in use.

30. A hose assembly comprising a hose as defined in any of Claims 18 to 27, and a hose clamp, the hose clamp comprising a flexible band that may be formed into a loop encircling the clamping surface of the hose, wherein, in use, the outwardly-protruding formation or member bears against a first surface of the band that is innermost when the band is formed into the loop, thereby defining said contact area through which clamping pressure is exerted on the hose.

31. A hose assembly comprising a hose and a hose clamp, wherein the hose clamp comprises: a flexible band having a proximal end and a free distal end, and a locking head at the proximal end of the band, the locking head having a passage into one end of which the distal end of the band may be inserted to the extent that the distal end protrudes from the other end of the passage, the band thereby forming a loop that can be tightened by gripping and pulling the protruding distal end away from the locking head, the locking head then being co-operable with the band to lock the loop in a tightened condition; wherein the hose comprises: an end portion defining an opening for receiving a male coupling member, and a cylindrical clamping surface extending around the end portion and being co-operable with the encircling band of the hose clamp; and wherein at least one formation or member between an inner surface of the band and the clamping surface of the hose defines a contact area that is smaller than the area of the inner surface or the clamping surface and through which, in use, clamping pressure is exerted by the band on the hose.

32 A method of clamping an end portion of a hose to a male coupling member of a vehicle component using a hose clamp, the hose clamp comprising a band, and the method comprising: forming the band into a loop around the end portion of the hose; tightening the loop around the end portion by pulling an end of the band, and locking the loop in a tightened condition to clamp the hose to the male coupling member.

33. The method of Claim 33, wherein locking of the loop takes place automatically upon pulling the loop into the tightened condition

34. The method of Claim 33 or 34, wherein the band is passed around the end portion of the hose to form the loop after said end portion has been fitted to the male coupling member.

35. The method of Claim 33 or 34, wherein the band is formed into a loop, and the loop is located around the end portion of the hose before the end portion is fitted to the male coupling member; the loop being tightened once the hose is fitted to the male coupling member.

36. A hose clamp substantially as herein described, with reference to or as shown in any of Figures 1 to 3, and Figure 7 of the accompanying drawings

37. A hose substantially as herein described, with reference to or as shown in any of Figures 2 to 7 of the accompanying drawings.

38. A hose assembly comprising a hose and a hose clamp, substantially as herein described with reference to or as shown in the accompanying drawings.