DESC:FIELD OF INVENTION

The present invention relates to positioning of parts to be machined on a CNC lathe machine. In particular, the invention relates to an attachment to be fitted on the tool post of the turret of CNC lathe machine. More particularly, the invention relates to a pusher attachment for accurately fixing the job on the CNC lathe machine chuck in a true or non-tilted position.

BACKGROUND OF THE INVENTION

It is observed that during machining on lathes, particularly on CNC lathes, the accuracy of machining of the jobs depends on the accuracy of fixing them on the machine chuck. Often, this job-fixing is not exactly true, i.e. job remains tilted even after fixing it on the machine chuck. This leads to inaccuracies during machining. In particular, due to the tilted position of the job fixed on the chuck, the face machining is not true enough. Although, the job is properly held between the chuck, there is improper resting of the job on the chuck, thereby there is a tilting of the job, which leads to inaccurate facing operation and which in turn results in an imperfectly machined job. This problem is more common in heavier machine parts such as differential cases, which are prone to such tilted and thereby defective fixing in the machine chuck. This leads to substantial rejection of the machined parts, which is a major disadvantage during the production of desired accurately machined parts. This occurs due to tilted fixing of heavy part, e.g. differential case on the machine chuck. So, this also leads to substantial rework or re-machining required to be carried out on such imperfectly machined differential cases, thereby increasing the final machining/production costs thereof.

Accordingly, in a conventional arrangement, the job to be machined is loaded on the CNC lathe machine chuck. Thereafter, the loaded job is brought in resting position on the rest pins of the lathe/CNC machine. The proper resting of a differential case totally depends on the skill of the operator. However, quite often errors were observed in proper resting of the job, which resulted in high rework, which led to higher costs with low rate of production.
DISADVANTAGES WITH THE PRIOR ART

Some of the major disadvantages of the conventional job fixing and holding arrangement on lathe machines are as under:

- No positive interlocking of the job
- Manual operation
- Complex procedure
- No process interlocking possible
- Excessive run-out on the joint face

The main reasons for the above disadvantages are as under:

- Unskilled operator
- Standard operating procedure not being followed
- Ignorance/non-attentiveness of the operator
- Lack of design interlock

Therefore, there is an urgent need to provide interlocking for proper or true resting of the job to be machined on the chuck face.

DESCRIPTION OF THE PRESENT INVENTION

Therefore, a unique pusher assembly is provided in accordance with the present invention, which is fitted in one the turret pocket holder of the CNC lathe machine (e.g. Mazak QN). A programme is written for the job using the standard ISO Code for using the CNC lathe turret. At the start of cycle, the pusher assembly holding turret is brought in an Auto mode. Subsequently, the pusher is made to touch the job to be machined and the spring of the pusher assembly is initially pressed by 5 mm. In Auto mode, machine is using the Built-in ISO M code, the chuck is opened and the job is pressed further by 15 mm. Now, the spring force is used further to push the job for proper resting on the CNC lathe machine chuck.
Thereafter, the chuck is closed using the Built-in function in the spring-pressed condition, which ensures a uniform job fixing and holding for true position thereof on the chuck. Finally, auto-machining function is initiated to accurately machine the job.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a pusher assembly for accurately holding the jobs to be machined on a lathe machine chuck.

Another object of the present invention is to provide a pusher assembly for facilitating true machining of the jobs a CNC lathe machine chuck.

Still another object of the present invention is to provide a pusher assembly for a CNC lathe machine programmable for mounting on CNC lathe turret.

Yet another object of the present invention is to provide a pusher assembly for a CNC lathe machine programmable as per profile of the job to be machined.

A further object of the present invention is to provide a pusher assembly for a CNC lathe machine which reduces operator fatigue.

A still further object of the present invention is to provide a pusher assembly for a CNC lathe machine which improves safety around the work environment.

A yet further object of the present invention is to provide a pusher assembly for a CNC lathe machine which achieves zero-defect targets.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.
SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a pusher assembly for accurate fixing and holding of jobs in lathe machine chuck, the assembly comprises:

- a pusher having a head and a leg;
- a receiver having a head and a leg; and
- a compression spring disposed between the pusher head and receiver head,

wherein the receiver includes a through bore for facilitating a sliding movement of the pusher leg inside the receiver for proper fixing and holding of the work-piece in the lathe machine chuck.

Typically, the pusher leg end disposed away from the pusher head includes an internal threading.

Typically, after inserting the compression spring on the pusher leg and sliding the pusher leg with compression spring into the bore of the received hear, a plate is fixed at the pusher leg end away from the pusher head for locking the pusher along with the compression spring in place.

Typically, the through bore in the receiver is configured in a stepped manner and having receiver leg bore being larger than the receiver head bore by a predetermined amount.

Typically, the receiver leg bore is smaller than the outer diameter of the compression spring.

Typically, the compression spring is made from wire having a diameter in a range of 3 to 4 mm, preferably 3.5 mm and the spring length is 60 to 100 mm, preferably 80 mm and the outer diameter of the spring is 20 to 40 mm, preferably 30 mm.
In accordance with the present invention, there is also provided a pusher assembly for accurate fixing and holding of jobs in lathe machine chuck, the assembly comprises:

- a pusher having a head and a leg and the pusher leg end disposed away from the pusher head includes an internal threading;

- a receiver having a head and a leg; and a stepped bore is configured through the receiver; and

- a compression spring disposed between the pusher head and receiver head,

wherein the receiver leg bore is configured higher than the receiver head bore to facilitate smooth and obstacle-free sliding movement of the pusher leg therein.

Typically, the compression spring includes an outer diameter higher than the bore in the receiver head and an internal diameter higher than the outer diameter of the pusher leg.

Typically, a plate is fixed by means of a fastener threaded in the internal thread provided at the pusher leg end away from the pusher head for locking the pusher along with the compression spring in place.

Typically, the pusher assembly is configured according to the type and weight of the load to be accurately positioned on the lathe machine chuck.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1 shows a conventional arrangement for fixing and holding a job to be machined on a lathe machine chuck.
Figure 2 shows a pusher assembly in accordance with the present invention for precisely fixing and holding a heavy job on a chuck of a CNC lathe machine.

Figure 3a shows a perspective view of the job to be machined held in a CNC lathe machine chuck in accordance with the present invention.

Figure 3b shows the perspective view of the pusher assembly in accordance with the present invention fitted in one of the turret pocket holders by means of a grub screw.

Figure 3c shows a perspective view of the pusher of the pusher assembly shown in Figure 3b moved rapidly with the spring of the pusher assembly just touching the job to be machined.

Figure 3d shows a perspective view of the pusher of the pusher assembly shown in Figure 3c compressing the spring of the pusher assembly in accordance with the present invention.

Figure 4a shows a detailed assembled view of the pusher assembly in accordance with the present invention.

Figure 4b shows the pusher of the pusher assembly shown in Figure 4a.

Figure 4c shows the pusher rod receiver of the pusher assembly shown in Figure 4a.

Figure 4d shows the spring for the pusher assembly shown in Figure 4a.

Figure 5a shows the conventional situation in which the operator manually pushes the job to be machined on the lathe machine chuck.

Figure 5b shows the operator ready to use the pusher mechanism in accordance with the present invention for fixing and holding a heavy job to be machined on the CNC lathe machine chuck.
Figure 5c shows of the pusher rod of the pusher assembly shown in Figure 5b just touching the job to be machined.

Figure 5d shows of the spring of the pusher assembly shown in Figure 5b completely pressed on the job to be machined.

Figure 5e shows of the pusher assembly shown in Figure 5b completely pressed on the job to be machined on the CNC lathe machine chuck, i.e. in its final true resting position achieved in accordance with the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a conventional arrangement showing a lathe machine chuck 10 for manually fixing and holding a job 20 to be machined on it by an operator 30.

Figure 2 shows a CNC lathe machine chuck 110 for precisely fixing and holding a heavy job 120 to be machined by means of a pusher assembly 130 configured in accordance with the present invention.

Figure 3a shows a perspective view of the CNC lathe machine chuck 110 holding a job 120 to be machined by the pusher assembly 130 (not visible here) configured in accordance with the present invention.

Figure 3b shows the perspective view of the pusher assembly 130 configured in accordance with the present invention fitted in one of the turret pocket holder 140 by means of a grub screw 150.

Figure 3c shows a perspective view of the pusher 132 of the pusher assembly generally shown by 130 just touching the job 120 to be machined after moving it rapidly by compressing the spring 136 (not visible here) of the pusher assembly by 20 mm to accurately fix and hold in true position on the machine chuck 110.

Figure 3d shows a perspective view of the pusher 132 of the pusher assembly shown in Figure 3c after compressing the spring 136 (not visible here) of the pusher assembly 130 by a predetermined distance, e.g. by 20 mm.

Figure 4a shows an assembled view of an embodiment of the pusher assembly 130 configured in accordance with the present invention. It consists of a pusher 132, a receiver 134 for receiving the pusher 132 and a spring 136 disposed between the pusher 132 and the receiver 134. The pusher 132 is axially moveable inside a through bore 138 provided in the receiver 134. The spring 136 is a compression spring, e.g. made from wire of 3.5 mm diameter, the spring length being 80 mm and the outer diameter of the spring being about 30 mm. However, the pusher assembly 130 can also be configured according to the type and weight of the load / job 120 to be accurately positioned on the CNC lathe machine chuck.

Figure 4b shows detail view of the pusher 132 of the pusher assembly 130 shown in Figure 4a. It includes a pusher head 132a, a pusher leg 132b extending from the pusher head 132a and configured with a internally threaded portion 132c at the other end thereof for fixing the pusher 132 on the receiver head 134a (as shown in Figure 4c). The pusher leg 132b has an external diameter d, which is configured for facilitating the sliding movement of the spring 136 in the pusher assembly 130.

Figure 4c shows the receiver 134 of the pusher assembly 130 shown in Figure 4a. It includes a receiver head 134a configured with a through bore 134c and a receiver leg 134b extending from the receiver head 134a. The receiver leg 134b has an internal diameter D, which is configured for facilitating the sliding movement of the pusher leg 132b inside the receiver head 134a. The receiver leg 134b also includes an internal bore 134d of diameter D1 therethorough, which is slightly larger than receiver head bore 134c.

Figure 4d shows the spring 136 for the pusher assembly 130 shown in Figure 4a. The spring is generally made of a steel wire, e.g. of 3.5 mm diameter. The internal diameter (D + x) of the spring 136 is slightly more than the internal diameter D of the receiver head 134 to retain the spring 136 between the pusher head 132a and the receiver head 134a. Whereas, the outer diameter of the spring 136 (D1 + y) is slightly greater than the bore 134d of the receiver leg 134b, so that the spring 136 is not pushed into the bore 134d of the receiver leg 134b on compressing the spring 136 on the job for achieving the true positioning of the job 120 on the CNC lathe machine chuck 110. Moreover, the bore 134d in the receiver leg 134 is slightly greater than the bore 134c of the receiver head 134c to allow smooth and obstacle-free sliding movement of the pusher leg 132b inside the receiver leg 134b.

Figure 5a shows the conventional situation in which the operator Op manually pushes the job 120 to be machined on the lathe machine chuck 110. However, as indicated, often there prevails a tilting of the job in the chuck even after the job is finally fixed and tightened in the jaws thereof. This results in higher rate of rejections and thus these imperfectly machined jobs require further reworking for making them acceptable for further assembly and/ or production process.

Figure 5b shows the operator Op ready to use the pusher mechanism 130 in accordance with the present invention on the CNC lathe machine chuck 110 to fix and hold a heavy job 120, e.g. a differential case to be machined thereon.

Figure 5c shows of the pusher rod of the pusher assembly 130 shown in Figure 5b just touching the job 120 to be machined.

Figure 5d shows of the spring 136 of the pusher assembly 130 shown in Figure 5b completely compressed on the job to be machined. In this position, there is a gap ‘A’ still remaining between the chuck 110 and the job 120.

Figure 5e shows of the pusher assembly shown in Figure 5b completely pressed with the job to be machined on the CNC lathe machine chuck, i.e. in its final true resting position achieved in accordance with the present invention. Here, the position shown by “B” has no or Zero gap between the chuck 110 and the job 120, so the desired true position of the job is achieved on the CNC lathe chuck, which facilitates machining of the jobs with zero rejections.

WORKING OF THE INVENTION:

In accordance with this invention, the pusher assembly for accurate fixing and holding of jobs in lathe machine chuck is used as under:

• Part to machined is held in the lathe machine (CNC) chuck.
• Pusher assembly is fitted in one of the turret Pocket holder by means of a Grub screw.
• Pusher turret is called in program by turret change.
• Pusher is moved rapidly and spring just touches the part.
• Part program made by using standard ISO Code for using Turret.
• Part just touches by compression spring in feed by about 20 mm.
• At the end of spring compression, the chuck opened by using chuck opening code.
• Spring Force of about 400 N ensures that the part rests properly.
• Chuck is closed using built-in function in the compression spring compressed condition, which ensures uniform part clamping.
• Auto-machining starts further.
• Load Applied about 400N.
• Spring Stiffness about 20 N/Mm.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The pusher assembly in accordance with the present invention has the following advantages:

• The requirement of the excellent skill of the workmen/machine operators for proper resting of the job on the CNC lathe machine chuck is eliminated by providing the interlock in machine itself.

• Pusher assembly and its component can be designed and manufactured in-house.
• No requirement for rework by using the pusher assembly proposed in accordance with the present invention

• Reduction in cost of poor quality products, which contributed in achieving the targets of Zero Manufacturing Defects.

• Customer satisfaction

• Boosts the employee morale by reducing operator fatigue

• Improves work environment by assuring the safety and eliminating operator fatigue.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.
Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Although the embodiments presented in this disclosure have been described in terms of its preferred embodiments, a person skilled in the art may make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention. ,CLAIMS:We claim:

1. A pusher assembly for accurate fixing and holding of jobs in lathe machine chuck, the assembly comprises:

- a pusher having a head and a leg;
- a receiver having a head and a leg; and
- a compression spring disposed between the pusher head and receiver head,

wherein the receiver includes a through bore for facilitating a sliding movement of the pusher leg inside the receiver for proper fixing and holding of the work-piece in the lathe machine chuck.

2. Pusher assembly as claimed in claim 1, wherein the pusher leg end disposed away from the pusher head includes an internal threading.

3. Pusher assembly as claimed in claim 2, wherein after inserting the compression spring on the pusher leg and sliding the pusher leg with compression spring into the bore of the received hear, a plate is fixed at the pusher leg end away from the pusher head for locking the pusher along with the compression spring in place.

4. Pusher assembly as claimed in claim 1, wherein the through bore in the receiver is configured in a stepped manner and having receiver leg bore being larger than the receiver head bore by a predetermined amount.

5. Pusher assembly as claimed in claim 4, wherein the receiver leg bore is smaller than the outer diameter of the compression spring.

6. Pusher assembly as claimed in claim 2, wherein the compression spring is made from wire having a diameter in a range of 3 to 4 mm, preferably 3.5 mm and the spring length is 60 to 100 mm, preferably 80 mm and the outer diameter of the spring is 20 to 40 mm, preferably 30 mm.

7. A pusher assembly for accurate fixing and holding of jobs in lathe machine chuck, the assembly comprises:

- a pusher having a head and a leg and the pusher leg end disposed away from the pusher head includes an internal threading;

- a receiver having a head and a leg; and a stepped bore is configured through the receiver; and

- a compression spring disposed between the pusher head and receiver head,

wherein the receiver leg bore is configured higher than the receiver head bore to facilitate smooth and obstacle-free sliding movement of the pusher leg therein.

8. A pusher assembly as claimed in claim 7, wherein compression spring includes an outer diameter higher than the bore in the receiver head and an internal diameter higher than the outer diameter of the pusher leg.

9. Pusher assembly as claimed in claims 7 and 8, wherein a plate is fixed by means of a fastener threaded in the internal thread provided at the pusher leg end away from the pusher head for locking the pusher along with the compression spring in place.

10. Pusher assembly as claimed in claims 1 to 9, wherein the pusher assembly is configured according to the type and weight of the load to be accurately positioned on the lathe machine chuck.

Dated: this day of 30nd June, 2015. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT