HOSE CLAMP

Abstract: An improved hose clamp of the kind comprising a steel strip (2) bent to annular shape with the end portions (5, 6) of the strip overlapping. The radially outer strip end portion (6) is formed on its external face with a lengthwise threaded passageway (7) having transverse grooves engaging the threads (8) of a headed worm (4). The worm is rotatably journalled in a sleeve (1) but axially non-slidable therein, said sleeve (1) enclosing the screw worm and comprising a space allowing the outer strip end portion (6) to be moved between the inner strip end portion (5) and the worm (4) by rotating the latter. The worm sleeve (1) is formed with lugs (10) gripping the outer strip end portion (6) at the radially inner face thereof and the inner strip end portion is formed with matching notches (11), the lugs (10) being insertable into said notches in abutment against the inner face of the outer strip end portion (6). The worm sleeve (1) is arranged, after interconnection of the lugs (10) and the notches (11) of the inner strip end portion (5) to prevent lengthwise movements of the inner strip end portion (5) relative to the worm sleeve (1).

Description: An Improved Hose Clamp The subject invention relates to an improved hose clamp of the kind comprising a steel strip bent to annular shape with the ends of the strip overlapping, the radially outer end portion of the strip being formed on its external face with a lengthwise extending threaded passageway having transverse grooves in which engage the threads of a headed worm, the latter being rotatably journalled in a sleeve but axially non-slidable therein, said sleeve enclosing the screw worm and comprising a space allowing the outer strip end portion to be displaced between the inner strip end portion and the worm by rotating the latter. In the manufacture of hose clamps of the kind outlined above the worm sleeve is generally produced from a tubular blank which is upset so that a space is formed to accommodate the worm and the two strip end portions. It is also known to manufacture the worm sleeve from a strip blank which is bent to the desired configuration, whereupon the lengthwise edge portions are welded together. The latter working step is difficult to effect in an automised manner at high speeds of assembly if a highquality standard is to be maintained. The bending operation to which the strip blank is subjected, is rather complicated, in consequence of which it becomes necessary to allow tolerance variations in the edge portions of the future weld Joint within certain limits. This, in turn, means that the finished weld Joint often has a bead, which hampers the subsequent assembly operation8. If instead, in order to obviate the risks of bead formation, the supply of welding material were to be reduced, someworm sleeves would as a consequence exhibit weak welding Joints. In using hose clamps of the kind above, being, as stated, provided with a worm sleeve enclosing the worm and the two strip end portions, damages to the hose material are sometimes found as also leakage beyond the hose clamp. Both problems are usually caused by the "thresholds" formed by the bottom of the worm sleeve both at the sleeve end where the inner strip end portion enters the worm sleeve and at the opposite end, where the outer strip end portion enters the worm sleeve, To solve this problem attempts have been made to machine the threshold portions of the worm sleeve bottom to ensure that the thickness of the sleeve bottom tapers from the sleeve centre towards the ends thereof, the threshold portions thus disappearing. This is suggested in .g. GB 559 653. However, this machine treatment weakens the worm sleeve and also increases the manufacturing costs to a not insignificant degree. It is also known to allow the inner strip end portion to extend through the worm sleeve so as to form a tongue in contact with the outer strip end portion and, at the opposite end of the worm sleeve, to form a Z-shaped section designed to urge the strip to a position close to the level of the worm sleeve bottom. Also these kind of arrangements do, however, raise the manufacturing costs and they also increase the amount of material used. The hose clamp in accordance with the subJect invention is designed to allow the manufacture of worm sleeves using a conventional strip blank as the starting material and without involving complex manufacturing operations, such as welding or riveting. It is characteristic of the invention that the worm sleeve is formed with lug portions gripping the outer strip end portion at the radially inner face of the latter, that the inner strip end portion is formed with notches matching the lug portions, the latter being arranged for insertion into said notches into abutment against the inner face of the outer strip end portion, that the worm sleeve is arranged, after interconnection of the lug portions and the notches of the inner strip end portion, to prevent lengthwise movements of the inner strip end portion relative to the worm sleeve, and that the inner strip end portion is arranged to prevent a transverse movement of the side walls of the worm sleeve. The arrangement in accordance with the invention provides safe and secure attachment of the inner strip end portion inside the worm sleeve without the use of locking means in the form of a notch in the inner strip end portion and a correspondingly shaped shoulder formed at the bottom of the worm sleeve to engage with said notches, which is the sonventional arrangement in priorart hose clamps. In addition, the arrangement in accordance with the subject invention also eliminates the threshold portions at the bottom of the worm sleeve. The invention will be described in closer detail in the following with reference to the accompanying drawings illustrating one embodiment of the invention by way of example. In the drawings Fig. 1 shows a hose clamp in accordance with the invention, Fig. 2 is a sectional view along line II-II in Fig. 1, Fig. 3 shows the two details of Fig. 2 detached from one another, and Fig. 4 is a sectional view along line IV-IV of Fig. 1. The hose clamp shown in the drawings comprises a sleeve 1, a steel strip 2 and a worm 4 with a head 3 thereon. The strip 2 is bent to an annular shape. Its radially inner end portion 5 is attached to the sleeve 1 and its radially outer end portion 6 is provided with a longitudinal threaded passageway 7 in which engage the threads 8 formed on the worm 4. The inner strip end portion 5 extends as a conically tapering tongue 9 past the worm sleeve 1 in contact with the outer end portion 6. As illustrated in Figs. 2 and 3 the bottom face of the worm sleeve 1 is provided with lug portions 10 gripping the outer strip end portion 6. The inner strip end portion 5 is provided with notches 11 having a shape matching that of the lugs 10. The edge walls 12 of the lug portions form an opening 13, which widens conically in a direction radially inwards in the hose clamp and in a corresponding manner the edge walls 14 of the notches 11 extend obliquely in the radial direction. Consequently, the inner strip end portion 5 may be inserted into the worm sleeve 1 until it is level with the sleeve bottom with the lug portions 10 engaging the notches 11. In this manner, the lug portions 10 prevent the inner strip end portion 5 from moving longitudinally relative to the worm sleeve 1. The strip end portions 5 may also be permanently attached to the worm sleeve 1 through stamping as at 15. Owing to this interconnection of the worm sleeve and the inner. st#ip end portion 5 there is obtained a hose clamp having an seven" inner face, e.g. without the thresholds found in prior-art hose clamps, which thresholds have hitherto necessitated a special configuration of the inner strip end portion or of the worm sleeve. The operation to bend the worm sleeve and to interconnect it with the inner strip end portion can be effected at high speeds in an automatic assembly machine. The manufacturing machinery may be simplified, since fewer working steps are required, owing to the simplified design. The inner face of the hose clamp has in ideal configuration ensuring that upon tightening of the clamp the compression force will be equally and uniformly distributed around the periphery of the clamp. As a result, the risk of leakage and damage to the hose material is eliminated. The configuration of the lug portions and the notches formed in the strip end portion 5 as shown and described herein serves to prevent the side walls of the worm sleeve from sliding apart, also when exposed to the stress occurring when the worm is tightened. Because the lug portions 10 grip about the outer strip end portion 6 they prevent this strip end portion from pressing the inner strip end portion 5 inwards in the hose clamp. The invention is not limited to the embodiment described above but a number of modifications are possible within the scope of the appended claims. For instance, the tongue 9 may be omitted, in which case the worm sleeve 1 and the inner strip end portion 5 may be suitably bevelled to provide a smooth transition area towards the outer strip end portion 6. Likewise, it is possible to turn the conicity of the opening 13 radially outwards, in which case the inner strip end portion 5 must be inserted into the worm sleeve in the space intended for the outer strip end portion 6 and then be moved down to its locking position. In this case stampings as at 15 probably are not needed. In addition, the lug portions 10 and the matching notches 11 obviously could be shaped differently from those shown. The interconnection of the joint parts between the worm sleeve 1 and the inner strip end portion 5 could also be effected by moving the hose clamp, at the end of the manufacturing path, past a laser, which is arranged to heat some or several joint areas and thus effect a total fusion of the worm sleeve to the inner strip end portion.

Claims: C L A I M S 1. An improved hose clamp of the kind comprising a steel strip (2) bent to annular shape with the end portions (5,6) of the strip overlapping, the radially outer end portion (6) of the strip being formed on its external face with a lengthwise extending threaded passageway (7) having transverse grooves in which engage the threads (8) of a headed worm (4), said worm being rotatably Journalled in a sleeve (1) but axially non-slidable therein, said sleeve enclosing the screw worm and comprising a space allowing the outer strip end portion (6) to be displaced between the inner strip end portion (5) and the worm (4) by rotating the latter, char a c t e r i S e d i n t h a t the worm sleeve (1) is formed with lug portions (10) gripping the outer strip end portion (6) at the radially inner face of the latter, in that the inner strip end portion (5) is formed with notches (11) matching the lug portions (10), the latter being arranged for insertion into said notches (11) into abutment against the inner face of said outer strip end portion(4 n that the worm sleeve (1) is arranged, after interconnection of the lug portions (10) and the notches (11) of the inner strip end portion, to prevent lengthwise movements of the inner strip end portion relative to the sleeve, and in that said inner strip end portion (5) is arranged to prevent a transverse movement of the side walls of the worm sleeve. 2. A hose clamp as claimed in claim 1, c h a r a c t e r i s e d in that the edge walls (12) of the lug portions (10) form an opening (13), said opening widening conically in a direction radially inwards in the hose clamp, in that in a corresponding manner the edge walls (14) of the notches (11) extend obliquely in the radial direction, and in that the contiguous areas common to the lug portions (10) and the notches (11) are provided with stampings (15), said obliquely extending edge walls (12-14) serving to prevent displacement of the inner strip end portion (5) relative the worm sleeve (1) in a direction radially outwards, and said stampings (15) serving to lock the inner strip end portion (5) relative to the worm sleeve (1) against movements radially inwards.

Inventors: RIBRANT, SVEN
Applicants: ALLMANNA BRANDREDSKAPSAFFAREN AB
Application year: 1983
Main classification: F16L33
IPC codes: F16L33