Title of Invention

AN IMPROVED WRENCH FOR LOSSENING AND TIGHTENING OF ROUND STOCKS AND HEX

Abstract

The invention relates to an improved wrench for loosening and tightening of round stocks and hex comprising: an operating handle (1); a fixed jaw (10) having an involute curved member (2) with unidirectional teeth (3) extending from a leading (H) to a trailing edge (A) for gripping the round stock, said fixed jaw (10) provided at the upper end of said handle (1); a movable jaw (4) having only an angular movement and pivotally held to said fixed jaw (10) through a pivot pin (8), said movable jaw (4) having an inner extending profile with teeth (5) cooperating with teeth (3) of the fixed jaw (10); the involute curved member (2) comprising a plurality of continuous curved surfaces (AB to GH), each curved surface formed between an imaginary forward and rear line (FL, RL) radiated from a pivot pin (P), each forward line (FL) has a rise (X) in length in comparison to its respective rear line (RL), the rise in length (X) of the forward lines (FL) of each curved surface (AB) being equal to each other, the angles between the forward and rear radiated lines (RL) of each curved surface are equal to each other.

Full Text

FIELD OF INVENTION This invention relates to a pipe wrench. Though reference is made to a pipe and its related fittings as one of the applications of the wrench of the present invention, it is not intended to be limited thereto and it may advantageously be employed with any round or hex stock. BACKGROUND OF THE INVENTION Pipe wrenches are known in the art and which normally comprise two jaws, one is a fixed jaw and another is movable jaw. A linear movement is imparted to the movable jaw by a mechanism similar to a screw and nut arrangement. Thus, a linear movement of the movable jaw is possible either towards or away from the fixed jaw and is imparted by the rotatable movement of a nut. When the pipe is held between the jaws of the wrench, the wrench is operated so as to release or tighten the grip on the pipe. A distinct disadvantage associated with such a known construction of a wrench is that for each operation the jaws are to be adjusted for gripping or release of the pipe. For each operation of the conventional pipe wrench to cause tightening or release of the grip on the pipe, it is necessary to adjust the jaws of the wrench by actuation of the nut. The nut is then again actuated so that the jaws grip the pipe and the rotatable movement of the wrench is repeated. It would be apparent that such a process is laborious, time consuming and inconvenient. Further, such a pipe wrench does not provide a firm and positive grip of the pipe or round stock. U.S. patent no. 5,251,518 describes a pipe wrench to comprise a handle having a teeth portion formed on the arenate edge of a curved portion at the upper end or fixed jaw of said handle. The pipe wrench further comprises a pivotable jaw which can be angularly displaced away or towards the fixed jaw to open or close the jaw of said wrench. The movable jaw has teeth co-operating with the teeth portion of the fixed jaw. The teeth of the movable jaw comprise of the two adjacent sides of a rectangle and such that the pipe is held between the two sides of the rectangle and the teeth portion of the fixed jaw. OBJECTS OF THE INVENTION An object of this invention is to propose a novel construction of a wrench employing an involute curved surface for opening and closing of any round stock and hex. Still another object of this invention is to propose a wrench having self adjusting properties and also which does not require any frequent adjustment for each rotation of the wrench. Yet another object of this invention is to propose a wrench which generates a consistent force upon all sizes of round stocks. Further objects and advantages of this invention will be more apparent from the ensuing description. DESCRIPTION OF INVENTION WITH REFERENCE TO ACCOMPANYING DRAWINGS The objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein: Fig. 1 shows the wrench of the present invention; Fig. 2 shows the profile of a gripping surface of a wrench having an eccentric curve; Fig. 2a shows the force graph of such an eccentric curve; Fig. 3 shows the involute curved surface of the wrench of the present invention; Fig. 3a shows the force graph of the involute curve; and Fig. 4 shows the wrench of the present invention with a round stock. Referring to fig.1, the wrench comprises of a handle 1 extending into a fixed jaw 10 of the upper end, said jaw 10 having an integrally formed involute curved member 2 at the upper end. The involute curved member 2 constitutes a specially designed curve, as described subsequently herein, to ensure a positive firm clamping of any size of a pipe or round stock between a pre-determined range. The involute curved member 2 has been designed in such a manner that the growth of the curve with reference to its own pivot 8 rises with equal angle and equal height. The involute curved member 2 has uni-directed angular teeth 3 (forming a smooth curve) to facilitate a positive firm action on the pipe, round stock, hex, etc. Involute curved member 2 has a leading edge H and trailing edge A. The pipe-wrench further comprises a movable jaw 4 having an angular displacement action and not a linear displacement action as known from the prior art. The movable jaw 4 has specially designed inner profile for maintaining optimum contact area and to facilitate positive firm grip for plumbing accessories like union (hex) etc. The movable jaw 4 has angular teeth 5 on two inclined surfaces 6 forming 120° included angle. The pipe or round stock ST (Fig. 4) is always clamped between the two inclined surfaces 6 of the movable jaw 4 and the involute curved member 2 in such a way that the tangent TL at the point of contact of the stock ST with the involute curved member 2 always coincides with the diameter of the pipe or round stock ST. This phenomenon of coinciding of the tangent TL and diameter of pipe or round stock ST remains constant for all variable sizes in the pipe wrench. The disc-washers 9 are placed at the pivot 8 on the both sides of the movable jaw 4 to prevent any free falling movement of the movable jaw 4. The object (pipe, round stock, hex union, etc.) is placed between the movable jaw 4 and the involute curved member 2 by pushing the movable jaw 4 from 7. By turning the handle 1, an optimum clamping force is generated in between involute curved -member 2 and the movable jaw 4. The harder handle is turned, the tighter it grips on to the object. This process is performed for clamping and rotating the object in desired direction. For repeated operations, handle 1 is returned to the original position and the object is reclamped again as explained above. Reference is made to the formation of the involute curved member 2. For this purpose, reference is first made to fig. 2 which shows the profile of a curved member 11 extending between a leading edge H and trailing edge A. The curved surface 11 of fig. 2 comprises of an eccentric curve, wherein the trailing edge A is disposed at an angle of 75° with respect to the horizontal axis of the pivot point 8. Further, the curve is formed by providing and unequal rise of sectors of the curve viz. AB, BC, CD, DE, EF, FG and GH. However, each sector AB to GH of the curved member 11 has the same centre O. Reference is made to fig. 2(a) which illustrates that the smaller diameter pipes receive a much higher force than required and that a middle sized diameter pipes receive much a lower force, resulting into slippage. Reference is now made to fig. 3 which illustrates the formation of involute curved member 2 of the present invention. Each of the curve surfaces AB, BC, CD, DE, EF, FG and GH are formed from two imaginary lines radiated from the pivot pin P. The two imaginary lines constitute a front or forward line FL and a rear line RL. The forward line FL for point B becomes the rear RL for point C. Thus the forward line FL for each of the points also form the rear lines RL for the next point. The lines PA to PH radiated from pivot 8 increases in equal lengths (heights) of x mms, for eg. 6.6 mm, and disposed at equal angle of, for eg. 15° from each other. Furthermore, the trailing edge A is disposed at an angle of, for eg., 75° away from the horizontal axis of pivot 8. Fig. 3(a) illustrates that the force applied on the stock is more uniform across different diameters of pipes. It has been found that the equal rise of each imaginary line radiated off the involute curved member 2 contributes in providing an uniformity of force applied on the pipe or stock. Further, and as will be apparent from the fig. 3(a), the force generated on to the pipes is proportionate to the diameter of the pipes namely, a relatively lesser force for smaller pipes and higher force for the bigger pipes. The equal angle between two radiated lines provides a smoothness of the curved surface 3. In fact, if such an angle is increased in a non-uniform manner, the curved surface would buldge too suddenly resulting in an improper grip on the stock. The pivot 8 constitutes the common centre through which the angular lines radiate. The involute curved member 2 is re-oriented to 75° with respect to vertical orientation of the handle 1 so that the smallest diameter and the biggest diameter openings will be distributed equally on both the sides of vertical position of the handle 1. This is to increase comfort operating of the wrench in different positions. We Claim --------------- 1. An improved wrench for loosening and tightening of round stocks and hex comprising: - an operating handle (1); - a fixed jaw (10) having an involute curved member (2) with unidirectional teeth (3) extending from a leading (H) to a trailing edge (A) for gripping the round stock, said fixed jaw (10) provided at the upper end of said handle (1); - a movable jaw (4) having only an angular movement and pivotally held to said fixed jaw (10) through a pivot pin (8), said movable jaw (4) having an inner extending profile with teeth (5) cooperating with teeth (3) of the fixed jaw (10); - the involute curved member (2) comprising a plurality of continuous curved surfaces (AB to GH), each curved surface formed between an imaginary forward and rear line (FL, RL) radiated from a pivot pin (P), each forward line (FL) has a rise (X) in length in comparison to its respective rear line (RL), the rise in length (X) of the forward lines (FL) of each curved surface (AB) being equal to each other, characterized in that the angles between the forward and rear radiated lines (RL) of each curved surface are equal to each other. 2. The wrench as claimed in claim 1 wherein the line extending between the pivot (8) and trailing edge (A) is angularly disposed with respect to the horizontal axis extending through the pivot (8). 3. The wrench as claimed in claim 1 wherein said movable jaw (4) is held to the fixed jaw (10) through the pivot pin (P) consisting two disc - washer (9) on both sides. 4. The wrench as claimed in claim 1 wherein said pivot pin (P) is disposed off centre with respect to the central vertical axis of the fixed jaw (10). 5. The wrench as claimed in claim 1 wherein the movable jaw (4) has a first and second set of teeth (5) with an included angle therebetween, and comprises an inclined surface (6) on either sides of an intermediate planar surface. 6. The wrench as claimed in claim 1 wherein a tangent line (TL) of the involute curved member (2) at the point of contact of the round stock (ST) coincides with the diameter of the round stock (ST). The invention relates to an improved wrench for loosening and tightening of round stocks and hex comprising: an operating handle (1); a fixed jaw (10) having an involute curved member (2) with unidirectional teeth (3) extending from a leading (H) to a trailing edge (A) for gripping the round stock, said fixed jaw (10) provided at the upper end of said handle (1); a movable jaw (4) having only an angular movement and pivotally held to said fixed jaw (10) through a pivot pin (8), said movable jaw (4) having an inner extending profile with teeth (5) cooperating with teeth (3) of the fixed jaw (10); the involute curved member (2) comprising a plurality of continuous curved surfaces (AB to GH), each curved surface formed between an imaginary forward and rear line (FL, RL) radiated from a pivot pin (P), each forward line (FL) has a rise (X) in length in comparison to its respective rear line (RL), the rise in length (X) of the forward lines (FL) of each curved surface (AB) being equal to each other, the angles between the forward and rear radiated lines (RL) of each curved surface are equal to each other.

Documents:

208-kolnp-2003-abstract.pdf

208-kolnp-2003-claims.pdf

208-kolnp-2003-correspondence.pdf

208-kolnp-2003-description (complete).pdf

208-kolnp-2003-examination report.pdf

208-kolnp-2003-form 18.pdf

208-kolnp-2003-form 5.pdf

208-kolnp-2003-gpa.pdf

208-kolnp-2003-granted-abstract.pdf

208-kolnp-2003-granted-claims.pdf

208-kolnp-2003-granted-correspondence.pdf

208-kolnp-2003-granted-description (complete).pdf

208-kolnp-2003-granted-drawings.pdf

208-kolnp-2003-granted-examination report.pdf

208-kolnp-2003-granted-form 1.pdf

208-kolnp-2003-granted-form 13.pdf

208-kolnp-2003-granted-form 2.pdf

208-kolnp-2003-granted-form 26.pdf

208-kolnp-2003-granted-form 3.pdf

208-kolnp-2003-granted-form 5.pdf

208-kolnp-2003-granted-specification.pdf

208-kolnp-2003-specification.pdf

208-kolnp-2003-translated copy of priority document.pdf