GB2122247A

GB2122247A - Hose clamp

Info

Publication number: GB2122247A
Application number: GB08312338A
Authority: GB
Inventors: George E Spaulding
Original assignee: Microdot Inc
Current assignee: Microdot Inc
Priority date: 1982-06-24
Filing date: 1983-05-05
Publication date: 1984-01-11
Also published as: CA1215219A; FR2536494B1; GB8312338D0; FR2536494A1; GB2122247B; DE3321908A1; JPS599388A

Abstract

A hose clamp is tightened by means of worm screw 18 engaging serrations 14. These serrations are covered by a relatively thin plastic liner 50, preferably, of polyester, which is held on by adhesive. This prevents the hose being forced through the serrations when the band is tightened. <IMAGE>

Description

SPECIFICATION Hose clamp Background of the invention Ladder-type hose clamps are often required to be lined with a member having tensile strength sufficient to prevent extrusion of hose material through serrations as clamping load is applied.

Known lined clamps use a metal foil liner applied with an adhesive and extending the full width of the strap. The thickness of foil material used may be adjusted to provide the strength required to prevent extrusion and damage to the hose but they are not ductile enough to allow the screw thread to enter the serrations without tearing or fracturing, and, in fact, any increase in thickness required to inhibit extrusion of the hose will aggravate the probability of damage at the screw. Moreover, since the liner extends the full width of the strap, as the strap with liner attempts to enter and pass through the housing and under the screw, the surface friction between the surfaces of the liner and the stationary strap will create shearing loads in excess of the strength of the adhesive, causing the liner to be stripped from the strap.Again, any increase in liner thickness will exasperate the shearing problem by increasing the compressive loads on the moving strap and, consequently, the frictional loads creating shear. Reuse of the clamp will be precluded by either puncturing the liner, stripping it free of the strap or both. The stripping or separation of the liner from the strap frequently compounds the problem since, free of the strap, it is apt to bunch or gather at the entrance to the housing or within it. Such bunching will alter the torque characteristics of the clamp and, if occurring in the vicinity or under the screw, will jam the mechanism. Additionally, it should be noted that an improper selection of metal for the liner may create accelerated corrosion of the clamp creating premature and catastrophic failure.

To be effective a liner should be strong, ductile and non-metallic. Moreover, it should be applied to the strap so that, in actual use, its entry into the housing will be limited, and, when it does enter the housing, it will pass clear of the bearing surface of the stationary strap. The liner should have as low a coefficient of friction as possible.

Summary of the invention The aforesaid problems are solved by the hose clamp of the instant invention through the use of a polyester tape which is bonded to the inner surface of the clamp by an adhesive. The tape exhibits a stretch coefficient of approximately 70% which insures thread engagement with the ladder section of the clamp yet does not result in perforation of the liner since the tap has sufficient stretch or ductility to preclude rupture thereof by the threads of the screw as the ladder of the clamp passes thereunder. The tape is chemically inert so as to preclude any chemical reaction with the hose or other materials encountered in the automotive environment. Moreover, since the polyester tape liner is secured to the inner surface of the clamp by an adhesive, there is no requirement for the tape to extend beyond the ends of the slots which define the ladder of the clamp.Thus, bunching of the tape under the clamp screw or within the housing of the clamp is minimized.

Brief description of the drawings Figure 1 is a plan view of the clamp prior to assembly; Figure 2 is an elevational view of a clamp with the clamp band assembled into a housing and with a screw secured in operative relation with both the band and housing; Figure 3 is a cross-sectional view taken substantially along the line 3-3 of Figure 1; Figure 4 is a view similar to Figure 2 with the housing partially broken away to illustrate deformation of the liner under the clamp screw; and Figure 5 is a view taken substantially along the line 5-5 of Fig. 4.

Detailed description of the preferred embodiment of the invention A clamp 10 comprises a strap 12 having a plurality of serrations 14 therein of ladder configuration for the acceptance of the threads 16 of a screw 18. The band 12 may be made from stainless steel or, when the clamp is not to be used in a corrosive environment, mild steel or aluminum.

A housing 20 is secured in an aperture 22 in the band 12 as by staking therein oppositely disposed tabs 24, 26 and 28, 30 of leg portions 36 and 38 of the housing 20. The screw 18 is journaled in a complementary arcuate recess 40 at one end of the housing 20, a head portion 42 of the screw 18 bearing against an end wall 44 of the housing to accept clamp loads on the clamp 10.

In accordance with the instant invention, the band 12 is provided with a relatively thin plastic liner 50, for example, commercial grade polyester tape that is one mill in thickness. The tape is secured to an inner face 52 of the band 12 by a synthetic adhesive which resists discoloration and chemical deterioration. Both the tape and the adhesive resist chemical reaction with the hose or other materials clamped by the clamp 10 encountered in the automotive or industrial environment.

It is to be noted that, as seen in Figure 1 of the drawings, the tape extends in width to an extent only necessary to cover the apertures 14 leaving spaced parallel side portions 54 and 55 which function as bearing surfaces for a pair of upstanding ears 56 and 58 on an end portion 60 of the band 12. As best seen in Figure 5, the ears 56 and 58 bear against the edge portions 54 and 55 on the underside of the band 12 outboard of the tape 50 precluding interference or bunching of the tape under the housing 20.

Claims

1. A hose clamp comprising a band having a plurality of longitudinally spaced laterally extending serrations therein a clamp housing engaged with one end of said clamp band, a screw journaled in said housing and having a thread engageable in said serrations, and a thin plastic tape secured to the inner face of said band and covering the serrations exposed to a hose being clamped by said clamp.

2. A clamp in accordance with claim 1 wherein said plastic tape is spaced inwardly from the edge portions of said band to provide a bearing surface for engagement with the opposite end portion of said band.

3. A clamp in accordance with claim 2 wherein the opposite end portion of said band is provided with a pair of upstanding ears for engagement with the edge portions of the first end thereof outboard of said tape.

4. A clamp in accordance with claim 1 wherein said tape is sufficiently ductile to accommodate the thread portion of said scerw without rupture of said tape.

5. A clamp in accordance with claim 1 wherein said tape is adhesively secured to the inner face of said band.

6. A hose clamp constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.