FIELD OF INVENTION
[001] This invention is related in general to hose clamp and particularly to worm clamp with adjustable internal diameter. The clamp controls minimum internal diameter of the clamp body, thereby preventing over compression of the hose clamped thereby.
BACKGROUND/PRIOR ART
[002] In general, a hose clamp is used to tighten a hose to prevent the hose from being loosened. For example, the hose may involve a hose used in a brake, an air conditioning system, a power steering system or an engine room for a vehicle to allow a flow passage of fluid or gas, or a hose fitted on a pipe or a connecting tube to allow a flow passage of fluid or gas in an industrial field.

[003] In order to prevent the hose clamp as described above or a hose from being damaged or deformed when the hose is tightened using the hose clamp, an assembling torque may be set or visibly indicated to enable the hose clamp to be assembled with reference to the set torque in an assembling field.
[004] However, when a technician performs an assembling work to comply with an assembly torque set at the time of designing, it is required to confirm a torque applied for tightening using a separate specific torque wrench or the like, and to separately confirm whether the assembling work is normally performed. Consequently, it is difficult to perform an efficient work.
[005] For this reason, an impact wrench, which is electrically, hydraulically or pneumatically operated, is used to quickly tighten the hose clamp, thereby maximizing the work efficiency.
[006] When the assembling work is performed in this manner, the tightening of the hose clamping may be quickly completed. However, upon being tightened using an electric power, hydraulic power or pneumatic power, the hose clamp may be frequently clamped by a torque that exceeds a limit torque as well as an optimum assembling torque set at the time of designing the hose clamp.
007] When the hose clamp is clamped by a torque exceeding the limit torque, the hose clamp and the hose tightened by the hose clamp may be damaged. Consequently, it is difficult to maintain the hose clamp and the hose at a normal condition after the clamping or tightening is completed. Furthermore, it is also difficult to visually confirm a damaged or ruptured condition during the assembling
process. As a result, a problem may be caused in that fluid or gas may leak out in the process of using the hose clamp or hose in the practically assembled state.
[008] There are various types of hose clamps available in the market including worm (screw/band) clamp, spring clamp, wire clamp, ear clamp. The present invention focuses on worm clamp for clamping hose.
[009] Worm clamps comprise of a galvanized or stainless steel band into which a screw thread pattern has been cut or pressed. One end of the band contains a captive screw. The clamp is put around the hose or tube to be connected, with the loose end being fed into a narrow space between the band and the captive screw. When the screw is turned, it acts as a worm drive pulling the notches of the band, causing the band to tighten around the hose (or when screwed the opposite drection, to loosen).
[0010] Now for clear understanding, the worm clamp can be described with reference to fig. 1 in which the clamp (1) is tightened or loosened by torquing the screw (2) as illustrated. This clamp can be employed to clamp rubber hose (1A) joined with a metallic pipe (2A) as shown in fig. 1A.
[0011] The aforesaid known clamp has long range of diameter and therefore goes beyond the required minimum diameter in case tightened at a little more torque than specified value because there is no provision to restrict movement of the screw.
[0012] Thus, the screw in the clamp goes beyond the last of notches (3) and slips over the flat surface of the clamp if further torque is applied.
[0013] As a result, internal diameter of the clamp is reduced further.
[0014] The above discussed construction gives rise the following drawbacks:-
-Development of crack in the hose.
- Leakage from the hose joint at clamp area.
- Reduction in the durability of hose i.e. shorter life span of hose.

[0015] In this regard, reference may be made to a patent US 2013/0280004 directing towards a torque control bolt for a hose clamp comprising a rupture bolt with a fastening body to transmit the torque from the tool to a head of the bolt, a coupling unit formed on the head and rupture bolt and a rupture section provided on the rupture bolt, wherein the rupture section comprises a notch. Here, torque is controlled by the torque valve of the bolt.
[0016] However, the patent is associated with several drawbacks, which can be listed hereinbelow:-

- Damage to head of bolt following application of particular torque.
- Though clamp can be employed for different outer diameter of the pipe and hose joint, but bolt needs to be changed every time so as to meet the torque requirement.
- Controlling is done by the application of torque on the head and at breakage of the head of bolt. Thus, clamp can be used only once as bolt breaks after achieving required torque, which is not replaceable with spare part.
[0017] In view of the above, it is required to devise a worm hose clamp which can address issues of prior arts and serve the purpose efficiently.
OBJECTS OF THE INVENTION
[0018] An object of the present invention is to provide a worm clamp with adjustable internal diameter which obviates shortcomings of prior art(s).
[0019] Another object of the present invention is to provide a worm clamp with adjustable internal diameter which is simple in construction.
[0020] Further object of the present invention is to provide a worm clamp with adjustable internal diameter which maintains minimum internal diameter even after application of further torque.
SUMMARY OF INVENTION
[0021] According to this invention there is provided a worm clamp with adjustable internal diameter comprising a clamp body constituting a loop of sheet metal, end of which is secured to a tightening/releasing module including a housing accommodating a screw, torquing of which varies internal diameter of the clamp, wherein the clamp body is provided with a plurality of notches together with a stopper to stop the clamp at minimum internal diameter.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0022] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of exemplary embodiments of invention and wherein:
Fig. 1 shows: Conventional worm clamp.
Fig. 1A shows: Conventional clamp clamping hose and pipe joint.
Fig. 2 shows: First embodiment of worm clamp according to present invention.
Fig. 2A shows: Stopper of first embodiment.
Fi. 3 shows: Second embodiment of worm clamp of present invention.
Fig. 4 shows: Third embodiment of worm clamp in accordance with the invention.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[0023] The instant invention pertains to hose clamp in particular worm clamp, internal diameter of which can be adjusted upto minimum.
[0024] Now, reference may be made to fig. 2, in which the worm clamp comprises a clamp body (1') constituting a circular loop formed by bending a narrow and long sheet member, in which a tightening/releasing module (2') is provided at/near one end of the clamp body. The module is provided to reduce or increase the diameter of clamp body in order to tighten or release a hose clamped with the help of said clamp.
[0025] This module includes a housing (3') accommodating a screw (4'). The screw is rotatably fitted inside the housing.
[0026] The rotatable screw is integrated to a plurality of threads across length thereof, which is engaged with a notch (5') formed in the clamp body in such a manner that, when the screw is rotated forwardly or reversely, the diameter of the circular loop of said clamp body is decreased or increased in order to tighten or release the hose.
[0027] However, in order to restrict sliding movement of the screw beyond the last notch (5'), an obstructing means is placed at the end of series of notches i.e. next to the last notch. The means constitutes a stopper (6').
[0028] Said stopper is an embossed part (6') as best seen in the fig. 2A. The embossed part can have a rectangular, trapezoidal section without restricting scope of the invention to the same. Thus, other profile of section obvious to a person skilled in the art is also included in the present invention.
[0029] Thus, the provision of said stopper after the last notch stops the clamp at minimum internal diameter thereof required for a particular application. This controls reduction of further diameter with application of extra torque by not allowing the screw to slide beyond the minimum diameter even with the application of the additional torque.
[0030] The above purpose can also be served by various other embodiments of invention, which will be discussed hereinbelow.
[0031] According to second embodiment of invention, for which reference may be made to fig. 3. Here, the stopper forms a strip of sheet (6A) which is fixedly secured onto the top surface of the clamp body. This strip is placed at the edge and covers nearly half of the clamp body width. The strip is positioned at a particular location on the clamp body to achieve minimum diameter. So that the screw can’t move beyond the minimum diameter even after applying the additional torque.
[0032] The strip can be welded/crimped on the clamp body, which is not necessarily required to take configuration of a substantially U- section as indicated in the exemplary embodiment. Thus, it can confirm to other shape as well.
[0033] Further, according to third embodiment of the present invention as illustrated in fig. 4, the stopper is a strip (6B) placed on the outer surface of the clamp body covering whole of the width. The strip is having substantially C-section. The strip is placed at a particular location to accomplish the required minimum diameter by preventing movement of the screw beyond said strip even after application of the extra torque. The strip is fixed onto the clamp body preferably by crimping.
[0034] The clamp of the proposed invention is preferably made of steel by the method of blanking, stamping, forming without limiting ambit of the invention to the same. Thus, other materials and methods readily apparent to a person skilled in the art are understood to be within purview of invention.
ADVANTAGEOUS FEATURES
- Controls minimum internal diameter even when subjected to extra torquing.
- Simple in construction.
- Easy in manufacturing.
[0035] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

Claims:WE CLAIM:
1.A worm clamp with adjustable internal diameter comprising a clamp body constituting a loop of sheet metal, end of which is secured to a tightening/releasing module including a housing accommodating a screw, torquing of which varies internal diameter of the clamp, wherein the clamp body is provided with a plurality of notches together with a stopper to stop the clamp at minimum internal diameter.
2. A worm clamp with adjustable internal diameter as claimed in claim 1 wherein the stopper constitutes an embossed part placed next to the last notch
3.A worm clamp with adjustable internal diameter as claimed in claim 2 wherein the stopper can have rectangular, trapezoidal section.
4.A worm clamp with adjustable internal diameter as claimed in any of the preceding claims wherein the stopper forms a strip of sheet metal which is fixedly secured onto the top surface of the clamp body.
5.A worm clamp with adjustable internal diameter as claimed in claim 4 wherein the strip placed at the edge covers nearly half of the clamp body width and is located at a particular location on the clamp body to achieve minimum diameter.
6.A worm clamp with adjustable internal diameter as claimed in claim 4or 5 wherein the strip is having substantially U-section.
7.A worm clamp with adjustable internal diameter as claimed in any of the preceding claims wherein the stopper is a strip placed on the outer surface of the clamp body at the required minimum diameter location covering whole of the width.
8.A worm clamp with adjustable internal diameter as claimed in claim 7 wherein the strip is having substantially C-section.
9.A worm clamp with adjustable internal diameter as claimed in any of the preceding claims is associated with the advantageous features such as herein described.
10.A worm clamp with adjustable internal diameter substantially as herein described with reference to the accompanying drawings.