HOSE CLAMP

Abstract: An improved hose clamp of the kind comprising a tightening band (13) which is bent to annular shape and which has end portions one of which (19) is provided with transverse grooves (20). In the latter engage the threads (16') of a screw worm (16) which is rotatably journalled in a sleeve (11) enclosing the screw worm but axially non-slidable therein. Said sleeve is formed with a space (21) allowing the threaded band end portion (19) to be moved out of the sleeve (11) upon rotation therein of the screw worm (16). The opposite band end portion (13) which is attached to the sleeve (11) is elastic in its lengthwise direction and encloses a pressure strap (12) which is bent to annular shape with its end portions (14, 15) overlapping. This pressure strap (12) is arranged to form a guide means to the screw worm sleeve (11) and to the tightening band (13, 19) between said sleeve and said band and an enclosed article. The tightening band (13) describes an arcuate line in the plane of the external face of the pressure strap (12) along the major portion of the circumference of the latter.

Description: Hose Clamp The subject invention concerns an improved hose clamp of the kind comprising a strip of material which is bent to annular shape to form a tightening band. One end portion of the band is provided with transverse grooves in which engage the threads of a screw worm which is rotatably journalled in a sleeve but axially non-slidable therein. The sleeve encloses the screw worm and is formed with a space allowing the threaded band end portion to be moved out of the sleeve upon rotation of the screw worm therein. The opposite band end portion 1s fixed to the sleeve. In prior-art hose clamps of the kind referred to above some leakage is sometimes found. Often the cause of such leakage 1s ageing of the material of the hose which 1s mounted by means of a hose clamp so that after some time of use the hose material loses Its pliability and elasticity. After a certain period it Is therefore necessary to re-tighten the hose clamp and eventually the hose must be exchanged. However, if this 1s done Incorrectly accidents or damage may occur. The problem 1s particularly common in the engine space 1n cars, where several hoses are fastened with the aid of hose clamps and where the environment causes considerable problems on account of the large variations in temperatures and of the presence of various liquids, such as petrol, oil, hydraulic fluids, glycol, alcohols and water. Furthermore, vibrations and oscillations of varying frequencies also contribute to the generation of leakage. One way of counter-acting the generation of leakage in hoses mounted by means of hose clamps is to increase the clamping action of the clamp by tightening the screw worm very hard. Clamp hose manufacturers have endeavoured for many years to produce stronger and more efficient hose clamps. However, when a hose clamp is " tightened hard it is inevitable that the clamp bites increasingly deeper into the hose material, which together with the vibrations and the tensile stress to which the material is exposed is liable to cause cracks in the hose material adjacent the clamp. The result is yet another problem. A more efficient method of obviating the ageing problems found in hose material in order to achieve a permanent clamping action in hose clamps 1s to provide the clamp with some kind of resilient means. DE-A-13130092 discloses a hose clamp the tightening band of which encloses a pressure strap and has a pleated or corrugated configuration. Owing to this configuration the tightening band assumes an elasticity 1n its lengthwise extension and 1n this manner becomes capable of compensating for the decreasing elasticity of the hose enclosed by the hose clamp. One disadvantage inherent In the wavy or corrugated configuration of the tightening band wherein the corrugations extend towards and away from the pressure strap positioned interiorly thereof is, however, that dirt particles may enter between the ridges and dales of the corrugations and the pressure strap. When this happens the strap loses at least part of Its resilient properties. By giving the tightening band an undulating configuration It is also, however, weakened. Consequently, the band must be made thicker than what 1s normal 1n order to compensate for the weaker structure and as a result the clamp becomes more expensive to manufacture. The purpose of the subject invention is to provide a hose clamp possessing resilient properties without the disadvantages outlined 1n the aforegoing. This Is achieved in accordance with the teachings of the invention therein that the tightening band enclosing a pressure strap bent to annular shape and having its end portions overlapping and arranged to form a guide means to the screw worm sleeve and the tightening band between said sleeve and said band and an enclosed article, descr bes an arcuate line 1n the plane of the external face of the pressure strap along the major portion of the circumference of the latter. The clamp 1n accordance with the Invention will be described 1n closer detail in the following with reference to the accompanying drawings, wherein Fig. 1 1s a perspective view of a first embodiment of the hose clamp in accordance with the Invention, Fig.2 is a sectional view along line II-II in F1g. 1, Fig. 3 illustrates a second embodiment of the hose clamp in accordance with the invention, and F1g.41s a sectional view along Hne IY-IV in Fig.3. The hose clamp illustrated in F1gs. 1 and 2 consists of a pressure strap 1 bent to annular shape and having Its end portions 2 and 3 positioned in overlapping relationship. The radially Inner end portion 2 of the strap is provided with outwardly projecting folded edges V which serve to guide the radially outer strap end portion 3. Around the pressure strap 1 extends a tightening band 4 in the form of a wire bent to zigzag shape. One end portion 5 of the wire is straight, flattened and provided with transverse grooves 6. The opposite end portion 7 1s helically wound into a cylindrical screw worm sleeve 8. A screw worm 9 is rotatably journalled but axially non-sl1dable In the sleeve 8 in which a space 10 1s formed (see F1g.2) allowing displacement of the threaded end portion 5 Inside the sleeve 8 upon rotation of the screw worm 9 with the screw worm threads 9' in engagement with the grooves 6. The wire used to form the tightening band 1s made from a tough-hardened material, such as piano wire, which imparts resilient properties to the zigzag-shaped portion. The pressure strap 1 preferably is made from a thin stainless steel strip. When the hose clamp 1s tightened about a hose end to secure the latter to a pipe end, the pressure strap 1 will be compressed about the hose end by means of the tightening band 4 so as to assume a predetermined diameter dimension corresponding to a maximum clamping force. Upon further tightening of the screw worm 9 the bent or curved portions of the tightening band 4 will be straightened against the action of the resiliency. As the hose material slowly ages the tightening band 4, on account of its springiness, will gradually compress the pressure strap 1 as the diameter size of the hose material 1s being reduced. This size adjustment will continue while maintaining a clamping force which is equal to the maximum clamping force minus the existing frictional resistance in the hose clamp. Figs. 3 and 4 show the hose clamp in accordance with a second embodiment of the invention. In this case the screw worm sleeve 11, the pressure strap 12 and the tigthening band 13 are made as one continuous unit from an elongate sheet metal strap. One free end of this continuous unit is formed by the radially inner one of the end portions 14 of the pressure strap 12. Like 1n the embodiment described 1n the aforegoing the latter 1s provided with outwardly directed folded edges 14' forming guide means to guide the movements of the radially outer end portion 15. The latter 1s attached to one end of the screw worm sleeve 11. A screw worm 16 1s rotatably journalled but axially non slidable In the sleeve. The screw worm sleeve 11 consists of two flaps of the strap material which are interconnected by means of a welding seam 17 on the upper face of the sleeve. On either side of the sleeve 11 the strap material 1s upset Inwardly by means of punch marks 18 which are arranged to engage in a manner known per se in a groove 1n the screw worm 16 adjacent the head 16' thereof. The tightening strap 13 which 1s a zigzag shaped punching from the strap material, extends from the opposite end of the screw worm sleeve up to a straight end portion 19 which is provided with transverse grooves 20. In the latter engage the threads 16' of the screw worm 16 when the end portion 19 is positioned in the space 21 inside the screw worm sleeve 11. Upon tightening, the hose clamp in accordance with Figs. 3 and 4 will behave in the same manner as the hose clamp in accordance with the embodiment of Figs. 1 and 2. The Invention is not limited to the embodiments described in the aforegoing but a number of modifications are possible within the scope of the appended claims. The screw worm sleeve 8 in accordance with the embodiment of Figs. 1 and 2 need not be made from the wire but could be made from sheet metal in the conventional manner in the art and the wire be secured thereto. In the second embodiment the radially outer end portions 15 of the pressure strap need not be secured to the screw worm sleeve 11.

Claims: CLAIMS 1. An improved hose clamp of the kind comprising a * tightening band (4; 13) which is bent to annular shape and having end portions (5, 7; 19) one of which is provided with transverse grooves 5 (6, 20) In which engage the threads (9'; 16') of a screw worm (9; 16), said screw worm being rotatably journalled in a sleeve (8; 11) but axially non-slidable therein, said sleeve enclosing the screw worm (9;16) and being formed with a space (10; 21) allowing the threaded band end portion (5; 19) to be moved out of the sleeve (8; 11) upon 10 rotation of the screw worm (9; 16) therein, the opposite band end portion being attached to said sleeve, and which tigthening band (4; 13) 1s elastic in its lengthwise direction and encloses a pressure strap (1; 12) which is bent to annular shape with the strap end portions (2, 3; 14, 15) overlapping, said pressure strap (1; 12) being 15 arranged to form a guide means to the screw worm sleeve (8; 11) and to the tightening band between said sleeve and said band and an enclosed article, c h a r a c t e r i z e d therein that said tightening band (4; 13) describes an arcuate line in the plane of the external face of the pressure strap (1; 12) along the major portion of the circumference 20 of the latter. 2. An improved hose clamp as claimed in claim 1, c h a r- a c t e r l z e d therein that the tigthening band (4) 1s in the form of a wire one end portion (5) of which 1s flattened and provided with said transverse grooves (6) and which band extends from this end 25 portion (5) to the opposite one 1n the form of a loop formed with a . plurality of curved portions. 3. An Improved hose clamp as claimed in claim ^ c h a r¬ a c e r i z e d therein that the tightening band (13) 1s in the i form of a steel strap punched into zigzag configuration. 30 4. An improved hose clamp as claimed in claim 2, c h a r- a c t e r i z e d therein that the wire (4) of. the second end portion (7) is colled helically into a cylindrical screw worm sleeve (8).

Inventors: RIBRANT SVEN, RIBRANT, SVEN
Applicants: ALLMAENNA BRANDREDSKAPSAFFAERE, ALLMAENNA BRANDREDSKAPSAFFAEREN AB ABA-BOLAGEN
Application year: 1985
Main classification: F16L33
IPC codes: F16L33