Title of Invention	A JAW FOR POWER CHUCKS
Abstract	A jaw for chucks comprising [i] a tip having a gripping end and a dovetail end; [ii] a tip holder having holes for mounting the top holder in a chuck and a recess complementary to the dovetail end of the tip and adapted to slidingly receive and lock the top in the recess.

Full Text

FORM-2 -4 FEB 2005 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE Specification (See section 10 and rule 13) A JAW FOR CHUCKS GADRE SHASHANK WASUDEO, an Indian National of 1433, Shukrawar Peth, Pune 411 002, Maharashtra, India THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED:- 4 FEB 2005 This invention relates to jaws for chucks. In particular, this invention relates to jaws for power chucks. Power chucks are used on CNC lathes for clamping jobs [generally a work piece on which some operation is to be performed] on the chucks for carrying out a process on the job, typically a machining process. Power chucks have base jaws on which top jaws are mounted. A Job is actually clamped on the top jaws. There are two main types of top jaws. 1) Hard Jaws. 2) Soft Jaws Hard jaws are normally used to clamp a job at an unfinished diameter/profile. These jaws are hardened so have more strength & longer life. They have typically diamond shaped serrations on the clamping face. These diamond profiles bite in the job & give a very firm grip. This causes a small distortion on the clamped diameter profile of the job. Because of this, hard jaws are not used to clamp finished/areas or diameters of the job. Soft jaws are normally manufactured from mild steel & they are not hardened. Advantage of these jaws is that they do not bite in the job & so finished profiles or diameters are not damaged in the clamping operation. Another advantage is that, after fitting the soft jaws they can be bored on the machine to give any bore size & perfect concentricity. Soft jaw sets are normally used as one set for 2 one diameter, because, once bored to a particular diameter, bigger or smaller diameters do not fit in that bore. Both types of top jaws are manufactured to suit specific chuck models. Every type & size of chuck has different top jaw clamping specification. E.g. - Centre slot size, size serration, length, hole centre distance & no of holes. Therefore top jaws are not inter changeable for different chucks. This means that if there are two CNC machines in a shop having different power chucks, then it is necessary to keep different sets of top jaws even far the same operation. According to this invention there is provided a jaw for chucks comprising [i] a tip having a gripping end and a dovetail end; [ii] a tip holder having holes for mounting the tip holder in a chuck and a recess complementary to the dovetail end of of the tip and adapted to slidingly receive and lock the tip in the recess. Typically, the tip holder is provided with a threaded hole for mounting and securing a screwing fixture therein for securing the tip to the tip holder. Typically, the dovetail end of the tip is defined by a section, angled in two directions one in a direction parallel to the operative X axis where the contained angle between angled side walls of the section is between 15 to 25 degrees and the other in a direction parallel to the operative Y axis, 3 the contained angle between angled side walls of the section being between 2 to 8 degrees. The tip is soft to form a soft jaw. Alternatively, the tip is hardened to form a hard jaw. An object of this invention is that the jaw is replaced by a composite jaw having a hard base for top jaws & soft or hard tips to fit in the base. These tips after fitting in the hard base, can be bored to any required diameter just as soft top jaws. This arrangement of composite top jaws eliminates removing the top jaws fully. Only the front tips are needed to be change. Thus saving considerable time in setting change. Base of the composite top jaws are hardened so they have very good strength & longer life. The tips are of small size & will cost around 30% of conventional soft jaws. These tips are provided in an easy identification box & will need much less storing space then conventional top jaws. Tips will fit in one composite top base of the jaw by self-locking tapered recess provided in the base & gives a very rigid clamping. Every chuck will require a top hard base jaws set may be of different specification. But the tip holding portion of top hard base jaws will be the same for same size of chucks. This will eliminate the need of keeping stock of different jaw set for different chucks. This will reduce the jaw inventory further. 4 Hardenable metal tips can be made available. This will reduce the usage of conventional top hard jaws. In accordance with a preferred embodiment of this invention the clamping arrangement facilitates clamping of hexagonal shapes, which is not possible with the hitherto prior art soft jaws. Tips will be available in a range for clamping jobs having different diameters. This will reduce the boring time. 1) As different jobs are done on CNC machines, changing of top jaws is frequent. This is necessary as different jobs have different diameters for clamping. Changing a top jaw set involves I) loosening the clamping bolts. II) Removing top jaws with bolts & T-nuts. III) Dismantling T-Nuts by removing bolts fully. IV) Assembling now top jaws set with T-nut & bolts. V) Inserting the T-nuts in base jaws VI) Locating the top jaws in positions VII) Clamping by tightening of bolts. VIII) Tying together the removed top jaws set. 2) After boring a few times, the whole set of soft jaws are currently scraped because the clamping portion & length of jaws keeps on reducing in each boring cut. Such a process is totally eliminated with the arrangement in accordance with this invention. 5 The invention will now be described with reference to the accompanying drawings, in which Figure 1 is an isometric view of a typical chuck for mounting jaws in accordance with this invention and in the prior art Figure 2 shows the jaws mounted on the chuck in the prior art. Figures 3, 3 A and 3B show the hard jaws of the prior art where mounted on the chuck. Figure 4 shows the assembled view of the composite jaw in accordance with this invention Figure 5 shows the blown up view of the composite jaw of figure 4; Figures 6a, 6b and 6c show the front view, the top plan view and the cut away side view respectively of the tip holder for the jaw in accordance with this invention; Figures 7a and 7b show the top plan view and a cut away view of an embodiment of a tip and tip holder assembly for the jaw in accordance with this invention Figures 8a and 8b show the top plan view and a cut away view of another embodiment of a tip and tip holder assembly for the jaw in accordance with this invention; Figures 9a and 9b show the top plan view and a cut away view of yet another embodiment of a tip and tip holder assembly for the jaw in accordance with this invention; Figure 10 is an explanation drawing for the angled dimensions of the dovetail end of the tip in accordance with this invention ; and Figure 11 shows the isometric view of a set of jaws with tip and tip holder mounted on a chuck in accordance with this invention; 6 Referring to the drawings, Figure 1 depicts a typically chuck 10 which is a power chuck. The mounting arrangements for mounting jaws are marked by reference numeral 12. These mounting recesses 12 in the nature of grooved slides can receive soft or hard jaws 14, 14a and 14b of the prior art. Figures 2 and figures 3, 3A, and 3B depict the chuck and jaw arrangement in accordance with the prior art. Figure 3B typically shows a soft jaw body 14B of the prior art. Figures 4 and 5 depict the composite jaw 16 in accordance with this invention. The composite jaw 16 has a hard base body tip holder 18 in which is fitted the tip 20. The tip holder 18 has mounting holes 24 for mounting the jaw 16 on the chuck 10 in the mounting recess . The tip is defined by a gripping end 30 and a dovetail end 32. The tip 20 is further provided with a threaded recess 22 for receiving a nut 26 for locking the soft tip to the base tip holder 18 . The dovetailed end projection 32 and the recess 34 arrangement typically a dovetailed recess as seen in figure 5 is provided for locking the tip 20 in the base tip holder 18. The tips 20 may be soft or may be hardened. Figures 6a and 6b and 6c show the front view, the top plan view and the cut away side view respectively of the tip holder for the jaw 16 in accordance with this invention. Figures 7a and 7b and 8a and 8b and 9a and 9b are end views of tips 20 showing alternative configurations of the dovetail end 32 of the tip 20 . Figure 10 is an explanation drawing for explaining the theory of locking of the tip in the tip holder for the jaw and the angles provided at the 7 dovetailed end of the tip which is defined by two tapering surfaces perpendicular to each other . The dovetail end of the tip is defined by a section, angled in two directions one in a direction parallel to the operative X axis where the contained angle between angled side walls of the section is between 15 to 25 degrees and the other in a direction parallel to the operative Y axis, the contained angle between angled side walls of the section being between 2 to 8 degrees. As seen in figure 10 which represents the dovetailed end the angle 'A0' represents the contained angle of a first tapering surface of the dovetailed end and the contained angle 'B0' represents the contained angle of a second tapering surface perpendicular to the first tapering surface. The contained angle A may vary between 15 and 20 degrees and is preferably 20 degrees whereas the contained angle B may vary between 2 and 8 degrees and is preferably 6 degrees 30 minutes. The taper on two surfaces provide a self locking feature of the tip and tip holder for the jaw in accordance with this invention . The dovetailed end is therefore self locking in the recess in the tip holder. The arrangement locks the tip in the holder in two axes. The nut 26 and washer 27 as seen in the arrangement in figure 5 provided fit within the recess 36 and a recess in the holder which prevents displacement in the third axis also. Once the tip is fitted in the tip holder it is not possible to unlock it by hand. The threaded recess 24 in the dovetail is used along with a puller [not shown] for extracting the tip from its holder. The self locking arrangement ensures that the job is located and clamped on the chuck precisely. 8 Figure 11 shows the working of the jaw in accordance with this invention as mounted on the chuck. As seen in the figure 3 jaws are fitted on the chuck to provide a fitment. The arrangement does not need removing of the jaw set and nut fully. Setting can be changed only by changing the tips 20 and moving the tip holder 18 forward or backward by a few serrations. This saves setting time significantly. The tips when refitted give an accuracy of 0.05 mm reducing the need of boring of the jaws thus increasing the life of the tips and reducing the setting time still further. Normally the jaw sets of the prior art after removing from the chuck are tied together and kept in racks. One set requires 100 sq cms of space. Identifying the correct size jaw is time consuming and it is very difficult to differentiate between 20mm diameter bore and 22mm diameter bore for example. The jaws in accordance with this invention do not pose such a problem at all and need much less space for storage as only the tips have to be stored. Different types of chucks are used on CNC machines such as closed centre chucks, hollow centre chucks, high speed chucks, eccentric compensating chucks and the like. In different types, slot size, serrations, hole sizes are different even for the same size chuck. When switching operation from one machine to another different size soft jaws are required. This increases the inventory. In accordance with this invention the tip holder of the jaw is the same for the same size chuck. This further reduces inventory. 9 While considerable emphasis has been placed herein on the structures and structural interrelationships between the component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principals of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. 10 I Claim: [1] A jaw for chucks comprising [i] a tip having a gripping end and a dovetail end; [ii] a tip holder having holes for mounting the tip holder in a chuck and a recess complementary to the dovetail end of the tip and adapted to slidingly receive and lock the tip in the recess. [2] A jaw for chucks as claimed in claim 1, in which the tip holder is provided with a threaded hole for mounting and securing a screwing fixture therein for securing the tip to the tip holder. [3] A jaw for chucks as claimed in claim 1, in which the dovetail end of the tip is defined by a section, angled in two directions one in a direction parallel to the operative X axis where the contained angle between angled side walls of the section is between 15 to 25 degrees and the other in a direction parallel to the operative Y axis, the contained angle between angled side walls of the section being between 2 to 8 degrees. [4] A jaw for chucks as claimed in claim 1, in which the tip is soft to form a soft jaw. [5] A jaw for chucks as claimed in claim 1, in which the tip is hardened to form a hard jaw. [6] A jaw for chucks as claimed in claim 1, in which the dovetailed end of the tip is provided with a threaded recess to assist in extracting the tip from the tip holder with a puller. 11 [7] A jaw for chucks as described herein with reference to the accompanying drawings. 12 ABSTRACT A jaw for chucks comprising [i] a tip having a gripping end and a dovetail end; [ii] a tip holder having holes for mounting the tip holder in a chuck and a recess complementary to the dovetail end of of the tip and adapted to slidingly receive and lock the tip in the recess. -4 FEB 2005

Documents:

1171-mum-2003-abstract(4-2-2005).doc

1171-mum-2003-abstract(4-2-2005).pdf

1171-mum-2003-abstract(complete).pdf

1171-mum-2003-abstract.doc

1171-mum-2003-cancelled pages(16-5-2008).pdf

1171-mum-2003-claims(complete).doc

1171-mum-2003-claims(complete).pdf

1171-mum-2003-claims(granted)-(16-5-2005).doc

1171-mum-2003-claims(granted)-(16-5-2008).pdf

1171-mum-2003-claims.doc

1171-mum-2003-correspondace-received-040205.pdf

1171-mum-2003-correspondace-received-051104.pdf

1171-mum-2003-correspondace-received.pdf

1171-mum-2003-correspondence(16-5-2008).pdf

1171-mum-2003-correspondence(ipo)-(10-6-2008).pdf

1171-mum-2003-description (complete).pdf

1171-mum-2003-drawing(4-2-2005).pdf

1171-mum-2003-drawings.pdf

1171-mum-2003-form 1(7-11-2003).pdf

1171-mum-2003-form 18(19-12-2006).pdf

1171-mum-2003-form 2(granted)-(16-5-2008).doc

1171-mum-2003-form 2(granted)-(16-5-2008).pdf

1171-mum-2003-form 26(7-11-2003).pdf

1171-mum-2003-form 3(7-11-2003).pdf

1171-mum-2003-form 4(10-11-2004).pdf

1171-mum-2003-form 5(4-2-2005).pdf

1171-mum-2003-form-18.pdf

1171-mum-2003-form-2(complete).pdf

1171-mum-2003-form-2(provisional).pdf

1171-mum-2003-form-2.doc

1171-mum-2003-form-2.pdf

1171-mum-2003-form-26.pdf

1171-mum-2003-form-3.pdf

1171-mum-2003-form-4.pdf

1171-mum-2003-form-5.pdf

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