DESC:FIELD OF THE INVENTION

The present invention relates to the assembly of connecting rod in the internal combustion engines. In particular, the present invention relates to the connecting rods fixture for locating and holding the same during assembly. More particularly, the present invention relates to a connecting rod fixture with locating-cum-indexing mechanism for number punching the connecting rods and caps of different types and models.

BACKGROUND OF THE INVENTION

In the internal combustion engine assembly plants, while removing the connecting rod caps, it is necessary to keep the caps in the correct sequence with the respective originally matched connecting rods. During original machining of the caps at the plant, first they were cut and assembled to the connecting rod and the bearing nest was bored subsequently. This bore is almost never exactly centred on the split line, which always resulted in a mix-up of the caps. This caused some bearings to get loosened and other bearings to get seized up on the crankshaft.

Therefore, it is always a good idea to mark the connecting rods and their respective caps for correct matching. This can be achieved either by number stamps or punch marks. Normally, one such unique mark/stamp is put on the cap end and another unique mark/stamp is put on the respective connecting rod.

PRIOR ART

In a conventional process for assembly of the connecting rod in an internal combustion engine, usually each operator manually uses a hammer for such number punching on the connecting rod and their respective caps. For example, this requires about 1504 hammer strokes per shift for an average volume of 188 four cylinder engines to be assembled per shift, which causes very high fatigue on the operator performing this number punching operation on the connecting rods and their caps.

Often, there are finger injuries caused to these operators. It should be noted that about 10 to 12 method steps are to be performed for every engine model changeover. Also, different locating fixtures are required for conducting cap removal process on different models and types of connecting rods. The applicant uses two types of diesel engines in their vehicles, i. e. Mahindra Direct (MDI) Engines and New Engine Family (NEF), which basically consist of Common Rail Diesel Engines (CRDe). Thus, both these types of engines require additional set-ups. The cap nuts have to be removed by using a pneumatic runner. There are two main operations, i.e. number punching and removal of the connecting rod cap to be performed by the operators. This operation becomes more complicated with a variety of connecting rods to be assembled in different types of engines, e.g. MDI engines or NEF engines.

DISADVANTAGES WITH THE PRIOR ART

In the course of the manual number punching operations on the connecting rods and respective caps by using a hammer, the repetitive hammering operation requires a large number of hammer strokes, which causes very high fatigue on the operator performing number punching. Often, there are finger injuries caused to the operators, which are costly as well as hamper the assembly process. This lowers the operator’s and thus plant’s overall output. Substantial amount of time is wasted due to large number of set-up changes to be made for different types of engines and various types of connecting rods thereof.

Therefore, there is a long-felt need for doing away with this manual number punching operation to speed-up the number punching process and to quicken the overall connecting rod assembly process. There is also a need for developing a unique solution, which caters to different engines and their different types of connecting rods, but without wasting time for changing different set-ups for the variety types of engines and their respective different types of connecting rods. This is also desirable from the point of view of simplifying the connecting rod assembly process in any internal combustion engine assembly plant.

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 simple mechanism for hammerless number punching of the connecting rods and their respective caps.

Another object of the present invention is to provide a locating fixture for accurately locating the connecting rod and their caps adjacent to each other for correct number punching thereon.

Still another object of the present invention is to provide an indexing mechanism for different types of connecting rods on variety of engines on a single locating fixture.

A further object of the present invention is to provide a cost-effective solution for connecting rod number-punching and assembly.

A still further object of the present invention is to provide a connecting rod locating fixture which reduces operator fatigue.

Another object of the present invention is to provide a connecting rod locating fixture mechanism which requires the least set-up time, thereby reducing the overall cost of manufacture.

Still further object of the present invention is to provide an indexing mechanism, which accommodates all types of connecting rods in the locating fixture.

Yet further object of the present invention is to provide a locating fixture and indexing mechanism, which facilitates set-up changeover from outside th number punching machine.

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 an adjustable connecting rod locating fixture-cum-indexing mechanism, wherein the mechanism comprises:

(a) a connecting rod locating mechanism; and

(b) a connecting rod stroke length indexing mechanism;

wherein the connecting rod locating mechanism comprises a plurality of levers operated by an engagement lever for indirectly coupling to a spring-loaded mechanism for aligning to a predetermined stroke length of the connecting rod to be number punched by means of a externally slotted rotating disc.

Typically, the rotating disc comprises at least four slots configured circumferentially equally spaced apart on the external diameter thereof.

Typically, the mechanism comprises:

(i) a rotatable engagement lever;
(ii) a coupling;
(iii) a first link passing through a first pivot plate fixed at first support and connecting the engagement lever to the coupling;
(iv) a spring-loaded mechanism connected at one end thereof to a second pivot plate fixed to a second support and connected to a fixed platform at the other end thereof;
(v) a second link connected to a second pivot plate at one end thereof and connected to the coupling at the other end thereof;
(vi) the second pivot plate connected to the spring loaded mechanism for indirectly connecting the second link with the engagement lever;
(vii) the spring loaded mechanism connected to the second pivot plate at one end thereof and fixed to a fourth support at the other end thereof;
(viii) a wedge-guide fixed to a third support and configured with a head at the lower end thereof and an aperture in the centre at the upper end thereof; and
(ix) a rotating disc configured with a plurality of slots of different depths;

wherein the engagement and disengagement mechanism of the wedge-guide and rotating disc by rotating the engagement lever via first and second links to the spring-loaded mechanism constitutes a positive lock for number punching operation on the selected pair of connecting rod and cap and wherein each slot on the rotating disc is configured with the same width and a depth corresponding to the stroke length and model of a respective connecting rod to be number punched.

Typically, the wedge-guide comprises a wedge-shaped cavity configured for guiding a rectangular locking piece having an enlarged head portion corresponding to the width of the slots and depth equal to the least deep slot on the rotating disc.

Typically, the wedge-guide guides the width of the rectangular locking piece within the cavity thereof.

Typically, the spring loaded mechanism constantly ensures a positive pressure of the engagement lever for preventing the distortion thereof during operation of the mechanism for making the number punch impressions legible enough after the completion of the number punching operation.

Typically, the engagement lever is configured as a cantilever mechanism extending out of the number punching machine during number punching operation to ensure operator safety during the number punching operation.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

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

Figure 1 shows a conventional arrangement for removing connecting rod caps using a Teflon rod;

Figure 2 shows a conventional method of the connecting rod and cap number punching by operator using a hammer, which often requires a changeover in the set-up thereof;

Figure 3 shows the details of the number punching machine with a common locating fixture and indexing mechanism configured in accordance with the present invention.

Figure 4 shows another view of the number punching on the connecting rod and the caps thereof by using an indexing mechanism configured according to the present invention.

Figure 5 shows the implementation of a number punching machine with an indexing mechanism in accordance with the present invention for number punching on the connecting rods and caps applicable for all engine models;

Figure 6 shows the process of opening cap nuts on the connecting rods by a pneumatic runner;

Figure 7 shows the locking arrangement with a toggle clamp for quick opening provided in accordance with the present invention;

Figure 8 shows the connecting rod locating fixture with a unique common locating and indexing mechanism configured in accordance with the present invention;

Figure 9 shows a schematic arrangement of the common locating and indexing mechanism configured in accordance with the present invention for clamping connecting rods of different stroke lengths for different engines and models;

Figure 10 shows a typical display of programming for number selection according to the type of model to be number punched on the connecting rods/caps; and

Figure 11 shows details of the spring-loaded mechanism configured in accordance with the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The connecting rod locating fixture with an indexing mechanism configured in accordance with the present invention will now be described in more details with reference to the accompanying drawings, without limiting the scope and ambit of the present disclosure in any way.

Figure 1 shows a conventional arrangement for removing connecting rod caps using Teflon rod 2. Teflon rod 2 is normally used for removing the connecting rods and for placing them at different locations on the connecting rod number punching machine, which uses manual hammering for number punching on both the connecting rods and their respective caps. Very often, this causes a lot of fatigue to the operators performing the number punching operations and also requires substantial set-up time for different types of connecting rods for different models of engines, e.g. MDI or NEF engines, i.e. connecting rod having different stroke lengths for different models.

Figure 2 shows a conventional method for number punching on the connecting rod CR and number punching NP on the connecting rod caps CRC performed by the operator using a hammer 6. Often, this requires substantial set-up time for changeover. The operator holds a hammer 6 in hand 4 and manually performs the number punching operation. However, the connecting rod locating fixture is different for different engines, e.g. MDI and NEF engines due to the connecting rods CR of different stroke lengths used therein. For example, at 188 number of 4-stroke engines assembled per shift, the operator has to manually perform 1504 hammering strokes per shift by using number punch NP. This causes high fatigue and thereby, often causes finger injuries to the operator. Moreover, the cap removal also necessitates using different locating fixtures for different models. So, every time there is a change in the model to be number punched, at least 10 to 12 steps were required for any model changeover. Further, additional set-up time was required for changing over from MDI to NEF type of engines and vice-versa. The connecting rod cap nuts were usually removed by using a pneumatic runner. Therefore, the operations of number punching and connecting rod cap removal were performed manually using different set-up for MDI and NEF engines, which required substantial amount of time, thus the number punching process was quite slow.

Figure 3 shows the details of the number punching machine with the common locating fixture and indexing mechanism configured in accordance with the present invention. The connecting rod locating fixture 10 can be easily used to locate all variants of the connecting rods having different stroke lengths on the unique number punching machine. A changeover pin 12 is provided, which has a flat wedge shaped engagement, so that it can engage accurately and can sustain all types of loads. This wedge shaped engagement mechanism is configured in one piece and operated through a spring loaded mechanism with the help of a long engagement lever projecting out by using the guide support. A unique pivoted wedge shaped guide is devised to take care of engagement and disengagement of the set-up changeover pin 12 according to the different stroke lengths of various connecting rods. An additional support 14 is provided, disposed above the set-up change over pin 12. This support 14 guides the flat wedge shaped mechanism therethrough, so as to ensure the correct alignment as well to act as a guide to eliminate any breakage of the link in the long run. The number punching is carried out by a probe 16 using a pneumatic runner. Accordingly, number punch 2205 EXLS, Tier 4, 90 HP, LS, UP Speed, Compact, Tier 3, Regular Genset Connecting rods can all be number punched on this connecting rod locating fixture by implementing a spring loaded mechanism to select the engagement/disengagement with the different sized slots configured on a rotating disc. This mechanism can be easily operated from outside the number punching machine. Therefore, this mechanism provides a safe working environment to the operator throughout the number punching operation performed on different connecting rods/caps.

Figure 4 shows another view of the number punching of the connecting rod and caps thereof by using an indexing mechanism configured in accordance with the present invention. The indexing mechanism totally eliminates the set-up changeover time and makes it possible to change over the number punching operations for almost 8 types of connecting rods for different types of engines, e.g. MDI or NEF engines, just by using a quick-change mechanism shown in Figure 11 described below. Here, a set-up change-over engagement lever 18 and a set-up change over linkage 20 are provided. The connecting rods 22 are number punched by the number punching machine 24 in which, a pneumatic cylinder (not shown) is attached to the fixed arms of the connecting rod locating fixture. This facilitates an easy opening of the connecting rod cap, which were otherwise very tight and not easily opened in the conventional arrangements. Therefore, the solution in accordance with the present invention is much less strenuous as compared to manual number punching operation used earlier and thus, it substantially reduces the operator fatigue.

Figure 5 shows a side view of the locating fixture and indexing mechanism 26 configured in accordance with the present invention for implementing a common number punching operation on the connecting rod and the caps thereof. This figure shows a locking arrangement 28 provided with a quick open toggle clamp for set-up changeover 30, which can be used on all models of connecting rods and for all types of engine, whether MDI or NEF. Accordingly, all types and models of connecting rods can be accommodated by this locating mechanism 26 for changing over to any type of connecting rod, each of which has a different stroke length.

Figure 6 shows the process of opening cap nuts on the connecting rods CR by a pneumatic runner in accordance with the present invention. The pneumatic runner 32 and collector tray 34 for collecting the cap nuts have been suitably modified. This pneumatic runner 32 opens the cap nuts, which are collected in the tray 34 and then transferred to the next work station. Basically, it is configured to avoid any non-value adding activity. Previously, once the operator punched the number on the connecting rod cap CRC and connecting rod CR, the connecting rods were removed and then put into the locating fixture CRLF (Fig. 2). Subsequently, the nuts and bolts were opened by a nut runner. However, in the mechanism configured in accordance with the present invention, all these operations, such as number punching, set-up changeover, cap removal and nut or bolt removal are combined in one single step, and therefore the pneumatic nut runner 32 is provided at this location. Secondly, after removal, these connecting rod cap nuts are to be transferred to the online station, where the subassembly of connecting rod and pistons is to be assembled with the crankshaft. This requires transfer from offline station to online station, which is easy to retract and therefore on opening, the cap nuts are collected on the collector tray 34 to be picked up easily.

Figure 7 shows the locking arrangement with a quick opening toggle clamp provided in accordance with the present invention. It shows the unique indexing mechanism 36. This lock is connected to a rotating disc which is provided with slots of different sizes for adjusting the location of the connecting rod on the number punching machine according to their respective stroke lengths. Further, the front end of this lock end is configured as a flat wedge for proper engagement in the selected slot. This is flexibly connected above to the spring loaded mechanism. A cantilever dual linkage is also provided with a engagement lever disposed outside the number punching machine to be connected to this linkage for facilitating the operation of the indexing mechanism by selecting appropriate slot on the rotating disc thereof (Fig. 11).

Figure 8 shows the connecting rod locating fixture CRLF with a unique indexing mechanism configured in accordance with the present invention, which eliminates the necessity of set-up changeovers. This mechanism consists of a locating fixture along with a circular slotted disc 38, in which four slots are provided for accurately accommodating the connecting rods of different stroke lengths to match the number punching on the connecting rods and the respective caps thereof. Moreover, this mechanism is supported by a spring loaded locking arrangement to prevent any deflection or movement of the connecting rods by a positive locking during number punching operation. The spring loaded mechanism always ensures a positive pressure on the number punch during number punching operation to make punch impressions legible enough.

Figure 9 shows a schematic arrangement of the spring-loaded mechanism in accordance with the present invention for accommodating different type of connecting rods having different stroke lengths. The caps CRC are tightened on the connecting rods CR by means of the respective nuts 40. The connecting rods have stroke lengths L, which vary according to the model and the type of engine, e.g. MDI or NEF engine. The spring loaded mechanism 44 includes an engagement lever 42 for its operation. The indexing mechanism 46 facilitates to control the stroke length variation for different connecting rods, as discussed above.

Figure 10 shows a display of programming for number selection according to the type of model to be number punched. In this process, the operator selects the model by using a keyboard, and also selects the details of the group series. As per the standard operating procedure, the operator uses a start button for starting the number punching machine.

Figure 11 shows the details of the spring-loaded mechanism in accordance with the present invention to prevent any deflection or movement by a positive locking during the number punching operation on the connecting rods. The mechanism consists of an engagement lever 42 connected via a first link 44 at the coupling 48. The link 44 passes through a pivot plate 46 fixed at first support 50. The pivot plate 46 allows a linear movement of link 44 through an aperture (not visible) therein. This way, the first end of the engagement lever 42 is directly connected to the first link 44 which passes through the pivot plate 46 and the other end of this first link 44 is coupled to a coupling 48. A wedge guide 54 having a head 56 at its lower end and an aperture 58 in the centre at its upper portion is provided for engagement and disengagement with the rotating disc 60. This rotating disc 60 has at least 4 slots 62, 64, 66 and 68 for selectively engaging the head 56 of the wedge guide 54. There is another link 70, one end of which is connected to a pivot plate 72 which is fixed at second support 74. The other end of this second link 70 is coupled to the coupling 48 for indirectly connecting the spring loaded mechanism 76 with the engagement lever 42. The second pivot plate 72 is connected at it one end to a spring loaded mechanism 76. The other end of this spring loaded mechanism 76 is fixed to the platform 78. The wedge guide 54 can be moved through a fixed support 80 fixed at 52 for selecting the suitable slot (62, 64, 66 or 68) as per the connecting rod to be number punched according to its stroke length. Accordingly, by suitable movement and/or rotation of the engagement lever 42 and by selecting the respective slot (62, 64, 66 or 68) as per the desired connecting rod to be number punched according to its respective stroke length, all types and models of the connecting rods and caps can be number punched by the mechanism configured according to the present invention. Thus, the invention provides a solution for using the same locating fixture for number punching accurately on the connecting rods of different stroke lengths and models and their respective connecting rod caps.

WORKING PRINCIPLE OF THE INVENTION

• The locating fixture shown in Fig. 11 is configured with four slots of equal widths, but configured eccentrically to accommodate the variation in stroke lengths of the connecting rods of different types and models.

• The indexing mechanism in Figures 9 and 11 includes a spring loaded mechanism to always ensure a positive pressure of the engagement lever, to prevent any distortion during operation thereof and therefore the punched impressions are sufficiently legible after the completion of the number punching operation.

• The cantilever mechanism in Figures 9 and 11 includes an engagement lever extending out of the number punching machine during number punching operation to ensure that the operator’s hand need never remain inside the number punching machine. This ensures the safety of the workman during number punching operation due to easy operation of the engagement lever within just a fraction of a second, operated from outside the number punching machine.

• The overall connecting rod locating fixture with novel indexing mechanism is configured in such a way that during any changeover of the model, the machine operator need to just externally operate the engagement lever quickly and rotate the rotating disc of the indexing mechanism shown in Fig. 11. Therefore, all models and types of connecting rod having different stroke lengths can be placed in this unique single locating fixture, because the center distance is also changed by this set-up changeover.

TECHNICAL ADVANTAGES & ECONOMIC SIGNIFICANCE

Some of the technical advantages of the locating fixture and number punching mechanism using the unique indexing mechanism proposed in accordance with the present invention are as under:

1) Accommodates all types of connecting rods in a single locating fixture;
2) Substantially reduces the operator’s fatigue;
3) Extremely safe operation;
4) Facilitates a positive engagement of locating pin in the changeover pin;
5) Eliminates frequent set-up time;
6) Can be used on any type of engine, e.g. MDI or NEF engine; and
7) Easy to use and achieves accurate positioning of the number punching.

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, it does not imply excluding any other element, integer or step, or group of elements, integers or method steps. In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

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. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

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. In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples.

However, it should be understood that the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description. Therefore, innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

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. These and other changes in the preferred embodiment 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.

The exemplary embodiments were selected and described in order to be able to best represent the principles and their possible practical application underlying the invention. Thereby, the skilled persons can optimally modify and use the invention and its different exemplary embodiments with reference to the intended use. ,CLAIMS:We claim:

1. An adjustable connecting rod locating fixture-cum-indexing mechanism, wherein the mechanism comprises:

(a) a connecting rod locating mechanism; and
(b) a connecting rod stroke length indexing mechanism;

wherein the connecting rod locating mechanism comprises a plurality of levers operated by an engagement lever for indirectly coupling to a spring-loaded mechanism for aligning to a predetermined stroke length of the connecting rod to be number punched by means of a externally slotted rotating disc.

2. Mechanism as claimed in claim 1, wherein the rotating disc comprises at least four slots configured circumferentially equally spaced apart on the external diameter thereof.

3. An adjustable connecting rod locating fixture-cum-indexing mechanism as claimed in claims 1 to 2, wherein the mechanism comprises:

(i) a rotatable engagement lever;
(ii) a coupling;
(iii) a first link passing through a first pivot plate fixed at first support and connecting the engagement lever to the coupling;
(iv) a spring-loaded mechanism connected at one end thereof to a pivot plate fixed to a second support and connected to a fixed platform at the other end thereof;
(v) a second link connected to a second pivot plate at one end thereof and connected to the coupling at the other end thereof;
(vi) the second pivot plate connected to the spring loaded mechanism for indirectly connecting the second link with the engagement lever;
(vii) the spring loaded mechanism connected to the second pivot plate at one end thereof and fixed to a fourth support at the other end thereof;
(viii) a wedge-guide fixed to a third support and configured with a head at the lower end thereof and an aperture in the centre at the upper end thereof; and
(ix) a rotating disc configured with a plurality of slots of different depths;

wherein the engagement and disengagement mechanism of the wedge-guide and rotating disc by rotating the engagement lever via first and second links to the spring-loaded mechanism constitutes a positive lock for number punching operation on the selected pair of connecting rod and cap and wherein each slot on the rotating disc is configured with the same width and a depth corresponding to the stroke length and model of a respective connecting rod to be number punched.

4. Mechanism as claimed in claims 1 to 3, wherein the wedge-guide comprises a wedge-shaped cavity configured for guiding a rectangular locking piece having an enlarged head portion corresponding to the width of the slots and depth equal to the least deep slot on the rotating disc.

5. Mechanism as claimed in claims 1 to 4, wherein the wedge-guide guides the width of the rectangular locking piece within the cavity thereof.

6. Mechanism as claimed in claims 1 to 5, wherein the spring loaded mechanism constantly ensures a positive pressure of the engagement lever for preventing the distortion thereof during operation of the mechanism for making the number punch impressions legible enough after the completion of the number punching operation.

7. Mechanism as claimed in claims 1 to 6, wherein the engagement lever is configured as a cantilever mechanism extending out of the number punching machine during number punching operation to ensure operator safety during the number punching operation.

Dated this 29th day of January, 2015. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT