CA1215219A

CA1215219A - Hose clamp

Info

Publication number: CA1215219A
Application number: CA000427384A
Authority: CA
Inventors: George E. Spaulding
Original assignee: WITTEK INDUSTRIES Inc
Current assignee: WITTEK INDUSTRIES Inc
Priority date: 1982-06-24
Filing date: 1983-05-04
Publication date: 1986-12-16
Also published as: GB2122247B; GB8312338D0; DE3321908A1; FR2536494B1; JPS599388A; FR2536494A1; GB2122247A

Abstract

ABSTRACT

The disclosure relates to a hose clamp comprising a generally circular band having a plurality of longitudin-ally spaced laterally extending slots at one end and a clamp housing engaged with an opposite end of the clamp band. A portion of the opposite end of the band within the housing is provided with a pair of upstanding continu-ous ears at the laterally spaced outer extremities thereof for engagement with the laterally outer edge portions of the one end of the band. A screw is journaled in the housing and has a thread engageable with the slots. A thin tough ductile plastic tape having a stretch coefficient of approxi-mately 70% is secured to the inner face of the band and covers the slots exposed to a hose being clamped by the clamp to minimize extrusion of the hose through the slots upon tightening of the clamp about the hose. The tape also permits engagement of the screw thread within the slots without rupture of the tape. The plastic tape is spaced inwardly from the edge portions of the one end of the band to provide a metal bearing surface thereon for direct metal to metal engagement with the ears on the opposite end por-tion of the band.

Description

3L2~z~
HOSE CLAMP

ACKGROVND OF THE INVENTION

Ladder-type hose clamps are often required to be lined with a member having tensile strength suf-fi ient ~o prevent extrusion of hose material through ; ~ 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 pro-vide 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- ~ 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, sinc~ the liner extends the f~ll width of the strap, as the strap with liner attempts to enter and pass through the housing and under the screw, the sur-face 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. A~ain, any increase in ~ ~ g g~r~ e liner thickness will ~t~erst~-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 punc-turing the liner, stripping it free of the strap or both~ The stripping or separation of the liner from ~2~52~

the strap frequently compounds the proble~ since, free of the strap, it is apt to bunch or gather at the entrance to the housing or within it. Such bunching w111 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 creatinq pre-mature and catastrophic failure.
To be effective a liner should be strong, duc-tile 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 tape 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 reac-tion with the hose or other materials encountered in SZ~9 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.
Broadly speaking the present invention provides a generally circular hose clamp comprising a metal band having a plurality of longitudinally spaced laterally extending IO slots at one end thereof, 2 clamp housing engaged with an opposite end of the clamp band, a portion of the opposite end of the band within the housing being provided with a pair of upstanding continuous ears at laterally spaced outer - extremities thereof for engagement with laterally outer edge portions of the one end of the band, a screw journaled in the housing and having a thread engageable in the slots, a thin tough ductile plastic tape having a stretch coefficient of approximately 70% secured to an inner face of the band ~ and covering the slots to be exposed to a hose being clamped by the clamp to minimize extrusion of the hose through the slots upon tightening of the clamp about the hose yet per-mitting engagement of the screw thread within the slots - without rupture of the tape, the plastic tape being spaced inwardly from the edge portions of the one end of the band to provide a metal bearing surface thereon for direct metal to metal engagement with the ears on the opposite end por-tion of the band.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a plan view of a 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 lcm/rlt ~3~

52:19 i.c~.~ wil.:]1 ~oth t}~ l rlou~ q;
I~`i;lure 3 is a cross-sect iOln`~ I vie~ rA~n <iul~s-tan-ti~11y .~loi1cJ ~ 3-3 oi- ~
Figul:e 4 i~ a view similar to Fig. 2 with the housincJ
partial l~7 b~oken awa~- to illustrate c'.eLorn~ ion o:E -the liner unc1er the c]amp scre~-; and rigure 5 is a view taken substant ally along ti1e line 5-5 of F:ic~. 4.

DETAILED DESCRIPTION OF Ti-.E PRE-ERRED

_EMBODl~lEMT OF ThF._I V_MTION _ _ A clamp ]0 compr:ises a strap 12 havin~ a pluralit~-of apertures or slots 14 t}lerein of ladder cGnflguration for the accep1-ance o~ the threads 16 of a screw 18. The band l2 ma~ be macle -rom stainless s~eel or, when the clamp is not to be used in a corrosive environmert, mild steel or aluminum.

';(l/ ,~ _3~_ S:~IL~!
A housing 20 is secured in an aperture 22 in the band 12 as by staking therein oppositely disposed tabs 24l 26 and 28, 30 of leg portions 36 and 38 of the housing 20~ The screw 18 is journaled in a complemen-tary arcuate recess 40 at one end of the housing 20, a head portion 42 of the screw lB 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 i5 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 ln the automotive or industrial environ-ment.
It is to be noted that, as seen in Fig. 1 of the drawings, the tape extends in width to an extent only necessary to cover the apertures 14 leaving spa~ed parallel side portions 54 and 55 which function as bearing sur~aces for a pair of upstanding ears 56 and 58 on an end portion 60 of the hand 12. As best seen in Fig. 5, the ears 56 and 58 bear against the edge portions 54 and 55 on the underside of the band 12 out-board of the tape 50 precluding interference or bunching of the tape under the housing 20.
While ~he preferred embodiment of the inven-tion has been disclosed, it should be appreciated that ~lSZ~'9 the invention is susceptible of modif ication without departing from the scope of the following claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A generally circular hose clamp comprising a metal band having a plurality of longitudinally spaced laterally extending slots at one end thereof, a clamp housing engaged with an opposite end of said clamp band, a portion of the opposite end of said band within said housing being provided with a pair of upstanding con-tinuous ears at laterally spaced outer extremities thereof for engagement with laterally outer edge portions of the one end of said band, a screw journaled in said housing and having a thread engageable in said slots, a thin tough ductile plastic tape having a stretch coefficient of approximately 70% secured to an inner face of said band and covering the slots to be exposed to a hose being clamped by said clamp to minimize extrusion of the hose through the slots upon tightening of said clamp about the hose yet permitting engagement of the screw thread within the slots without rupture of said tape, said plastic tape being spaced inwardly from the edge portions of said one end of said band to provide a metal bearing surface thereon for direct metal to metal engagement with the ears on the opposite end portion of said band.