Title of Invention

A DEVICE FOR MOUNTING AND REMOVING COIL SPRING OF SHOCK ABSORBER ASSEMBLY AND METHOD THEREOF

Abstract

This invention relates to a device for mounting and removing coil spring of shock absorber assembly for automobiles comprising an upper support member mountable below the moving ram plate of a press, a lower support member having a connector to mount a shock absorber strut on the lower plate of said press, said upper support member having downwardly disposed vertical space members, a top plate connected to said vertical space members, said top plate holding a detachable cup shaped member with a central hole for holding the coil spring and the strut; locating means for vertical positioning of the strut when mounted and guide means to ensure that the axis of the top and bottom members are aligned. This invention also includes methods of mounting coil spring and removing the same with the above described device.

Full Text

FORM 2 THE PATENTS ACT 1970 (39 of 1970) AND THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See Section 10; rule 13) TITLE OF THE INVENTION A DEVICE FOR MOUNTING AND REMOVING COIL SPRING OF SHOCK ABSORBER ASSEMBLY AND METHOD THEREOF APPLICANTS TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India INVENTOR Chawadimani Chetan S. an Indian National of TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai - 400 001 Maharashtra, India PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed. FIELD OF INVENTION This invention relates shock absorber assembly and more particularly it relates to a device for mounting and removing coil spring of shock absorber assembly and method thereof. BACKGROUND OF INVENTION For all kind of sports utility vehicle, shock absorber assembly with spring is used for suspension action during dynamic condition. The assembly of spring with strut is critical as springs of different stiffness values are used during prototyping. The force required to compress the spring and assemble the upper cup always vary depending on stiffness value of spring. In the conventional method of manufacturing an assembly of strut and spring, the spring is held by two screws at middle portion. The two screws are used on both the sides (180° opposite) with threaded holding bracket on top and bottom to hold the spring solid bar in the middle portion. There is a hexagonal head provided on screws at one end for the rotation purpose. Disadvantages in conventional methods: a) Buckling of spring observed during compressing, which is not favourable in assembling with strut. b) Spring tool (Screw with bracket holding spring) always slips from the intended position because of the helical portion of the spring thus creating problem during assembly. c) Alignment of spring seat top studs with vehicle body in white sheet metal panel is difficult. The orientation changes due to rotation of spring during compression. d) To compress a spring, a very high force is required at the screw hex head end. e) More heat is generated at threads due to resistance by spring. f) The operation is unsafe, as there are chances of accident. OBJECTS OF THE INVENTION The main object of the present invention is to provide a device for mounting and removing coil spring of shock absorber assembly and method thereof. Another object of the present invention is to provide a device for mounting and removing coil spring of shock absorber assembly that avoids buckling of spring. Another object of the present invention is to provide a device for mounting coil spring of shock absorber assembly that creates exact orientation with respect to vehicle body in while matching holes. Another object of the present invention is to provide a device for mounting and removing coil spring of shock absorber assembly which avoids using spring as a holding device. Another object of the present invention is to provide a device for mounting and removing coil spring of shock absorber assembly which is simple in construction and safe. Another object of the present invention is to provide a device for mounting and removing coil spring of shock absorber assembly which reduces development time during prototyping SUMMARY OF INVENTION A device for mounting and removing coil spring of shock absorber assembly for automobiles comprises an upper support member mountable below the moving ram plate of a press, a lower support member having a connector to mount the strut on the lower plate of said press, said upper support member having downwardly disposed vertical space members, a top plate connected to said vertical space members, said top plate holding a detachable cup shaped member with a means for vertical positioning of the shock absorber strut when mounted and guide means to ensure that the axis of the top and bottom members are aligned A method for mounting coil spring of shock absorbers assembly with the above described device as comprises the steps of positioning the locator on said lower support member of the press, aligning said upper support member with said guide means such that the upper and lower plates are aligned, mounting said upper support members at respective locations, locating shock absorber strut vertically; inserting a coil spring into said strut from the top, connecting the cup shaped member to upper support plate, downwardly pressing the moving ram plate of said press till the coil spring compressed and the threaded part of said strut comes out of said cup, tightening said threaded portion to the cup, disconnecting said cup from the upper support plate and removing the assembly from the hydraulic press. BRIEF DESCRIPTION OF DRAWINGS Fig 1. Schematic view of the device. Fig 2. Isometric view of the device. Fig 3. Schematic view of the device with shock absorber strut coil spring assembly. DETAILED DESCRIPTION OF INVENTION Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same, Now referring to Fig 1 and 2, in accordance with this invention, the device comprises; a) upper support member (1) and lower support member (2) that are located on the bottom side of the moving ram plate (3) and the top side of the fixed lower plate (bed) (4) respectively of the hydraulic press (17). b) A top plate (5) fitted with vertical spacer (6) connected to upper support member. The top plate is having holes to insert the studs of upper cup. c) Connecting assembly (7) comprising means to locate and tighten the shock absorber strut eye (9) firmly after vertical alignment. d) Locator assembly (8) connected to the lower support member (2) to align the shock absorber strut vertically. e) An upper cup (10) of shock absorber assembly (with rubber seat fitted inside the cup (not shown in figure) with studs (11) to fit it to the top support plate (5). The upper cup is having central hole to locate the shock absorber strut top portion during the assembling. For assembling the shock absorber strut (12) and coil spring (13) in the above device, the lower support plate (2) with locater held loosely to the hydraulic press. The top support plate (1) with vertical spacers (6) and top plate (5) held to the bottom side of the moving ram plate (3) of the hydraulic press. The top support plate (refer figure 2) preferably is 'C shaped to give better access during the tightening the washers and nuts on the strut threaded portion. Upper cup is connected to top support plate. The studs (11) are inserted through the holes provided on the top support plate and tightened using nuts. Both plates are perfectly aligned with each other by using guide rods (16) shown in fig. I to ensure that the axis of the both plates and orientation is exact. In aligned condition both lower and upper support members (1 and 2) are fixed to respective location with the help of bolt and tee nut (15a, 15b). Once setting is completed, the guide bars (16) will be removed and the strut eye end (9) is located on lower support member (2) and held vertically by locators (8). The locator is 'Z' shaped, where the lower portion is connected to lower support member and top end with a 'U' bracket to hold the strut (refer figure 2). With locator (8), it will ensure that shock absorber strut (12) is exactly vertical. Now insert spring (13) into strut (12) from top. The shock absorber strut (12) is having a collar to hold the spring (13). Spring rubber seat (not shown) is inserted on spring (13) top correctly. Operation of the hydraulic press (17) is started in downward direction. The upper cup (spring seat top) (10) will start moving down and on reaching the spring top it holds the spring top in position and compress the spring (13). A guide bar (not shown) is provided to check the deflection required, the height of guide bar (not shown in figure) is decided in such a manner that it will stop the hydraulic press ram (3) at certain fixed location. At this position the threaded portion of the shock absorber strut (12) (top of the strut) will come out of upper cup through the hole at the centre, where we will be able to put rubber bush, washer and nut (14) to tighten the upper cup (10) to hold the spring (13) in the compressed position. Vertical spacers (6) on the upper plate (5) will create good access for tightening nut from all side. The maximum height of the vertical spacers is decided by amount of displacement expected while compressing the spring (13). Once nut tightening operation on strut (12) central shaft thread is completed, the top support plate (5) mounting on upper cup (10) is removed after loosening nuts on studs (11). Raise hydraulic ram to upside and remove complete assembly of strut and spring easily. The same arrangement is used for removing a compressed spring from a shock absorber assembly. For removing compressed spring the steps followed in the above assembling method has to be followed in reverse order. The strut and spring assembly is placed on lower support plate. The strut is tightened to the locator and held vertically. Starting hydraulic press operation in downward position, once the upper support plate reaches on the upper cup, locate the studs on upper cup in the holes provided on the support plate. Tightening the nuts on the studs to hold the upper cup firmly on the upper support plate. Removing the upper bush and washer on the strut. Starting hydraulic press operation in the upward position. The upper cup will start moving upwardly along the upper support plate and releases the compressed spring. The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof. WE CLAIM 1) A device for mounting and removing coil spring of shock absorber assembly for automobiles comprising an upper support member mountable below the moving ram plate of a press, a lower support member having a connector to mount a shock absorber strut on the lower plate of said press, said upper support member having downwardly disposed vertical space members, a top plate connected to said vertical space members, said top plate holding a detachable cup shaped member with a central hole for holding the coil spring and the strut; locating means for vertical positioning of the strut when mounted and guide means to ensure that the axis of the top and bottom members are aligned. 2) The device for mounting and removing coil spring of shock absorber assembly for automobiles as claimed in claim 1, wherein said press is a hydraulic press. 3) The device for mounting and removing coil spring of shock absorber assembly for automobiles as claimed in claim 1, wherein said cup shaped member is mounted on said top plate with studs and nut. 4) The device for mounting and removing coil spring of shock absorber assembly for automobiles as claimed in claim 1 wherein said vertical space members are capable of creating a space between said upper support plate and top plate to accommodate the threaded portion of said strut and a space for inserting a bush and washer. 5) The device for mounting and removing coil spring of shock absorber assembly for automobiles as claimed in claim 1 wherein said locating means is a 'Z' shaped bracket with a 'LP shaped bracket at top end to hold said strut. A method of mounting coil spring of shock absorbers assembly with a device as claimed in claims 1 to 5 comprising the steps of positioning the locator on said lower support member of the press, aligning said upper support member with vertical spacers and top plate below the moving ram plate using said guide means such that the upper and lower plates are aligned, mounting said support members at respective locations, locating said mounted strut vertically; inserting a coil spring into said strut from the top, connecting a cup shaped member to top plate, downwardly pressing the moving ram plate of said press till the coil spring is compressed and the threaded part of said strut comes out of said cup, tightening said threaded portion of the strut to the cup, disconnecting said cup from the top plate and removing the assembly from the hydraulic press. A method of removing coil spring of shock absorbers assembly with a device as claimed in claims 1 to 5 comprising the steps of positioning the locator on said lower support member of the press, aligning said upper support member with vertical spacers and top plate below the moving ram plate using said guide means such that the upper and lower plates are aligned, mounting said support members at respective locations, locating said shock absorber assembly vertically; downwardly pressing the moving ram plate to locate the top plate on said upper cup, attaching said cup to said top plate using bolts and nuts, removing the washer and nut on the threaded portion of the strut so that the upper cup is moved to release the spring, raising the hydraulic press to release compression in the spring, removing the spring from the assembly. 8) The device for mounting and removing coil spring of shock absorber assembly for automobile substantially as herein described with reference to accompanying drawings. 9) The method of mounting and removing coil spring of shock absorber assembly for automobile substantially as herein described with reference to accompanying drawings. ABSTRACT A device for mounting and removing coil spring of shock absorber assembly and method thereof This invention relates to a device for mounting and removing coil spring of shock absorber assembly for automobiles comprising an upper support member mountable below the moving ram plate of a press, a lower support member having a connector to mount a shock absorber strut on the lower plate of said press, said upper support member having downwardly disposed vertical space members, a top plate connected to said vertical space members, said top plate holding a detachable cup shaped member with a central hole for holding the coil spring and the strut; locating means for vertical positioning of the strut when mounted and guide means to ensure that the axis of the top and bottom members are aligned. This invention also includes methods of mounting coil spring and removing the same with the above described device. Fig.l

Documents:

491-mum-2008-abstract.doc

491-mum-2008-abstract.pdf

491-MUM-2008-CLAIMS(AMENDED)-(14-6-2012).pdf

491-MUM-2008-CLAIMS(AMENDED)-(30-7-2013).pdf

491-MUM-2008-CLAIMS(MARKED COPY)-(14-6-2012).pdf

491-mum-2008-claims.doc

491-mum-2008-claims.pdf

491-mum-2008-correspondence(17-3-2008).pdf

491-mum-2008-correspondence-received.pdf

491-mum-2008-description (complete).pdf

491-MUM-2008-DRAWING(30-7-2013).pdf

491-mum-2008-drawings.pdf

491-mum-2008-form 18(17-3-2008).pdf

491-mum-2008-form 2(title page)-(11-3-2008).pdf

491-mum-2008-form 8(17-3-2008).pdf

491-mum-2008-form 9(17-3-2008).pdf

491-mum-2008-form-1.pdf

491-mum-2008-form-2.doc

491-mum-2008-form-2.pdf

491-mum-2008-form-26.pdf

491-mum-2008-form-3.pdf

491-MUM-2008-MARKED COPY(30-7-2013).pdf

491-MUM-2008-REPLY TO EXAMINATION REPORT(14-6-2012).pdf

491-MUM-2008-REPLY TO HEARING(30-7-2013).pdf

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