INCORPORATING SUCH REMOVAL TOOL

FIELD OF THE INVENTION

The present disclosure concerns after sales tooling to repair automotive diesel pumping injectors and more precisely concerns a removal tool for removing a thrust socket of a pumping injector in order to check, clean or replace such part and other parts such as a pumping plunger.

The disclosure also concerns a tool kit incorporating such removal tool and mounting tools to put a thrust socket back in place.

BACKGROUND OF THE INVENTION

Heavy-duty pumping injector comprises a thrust socket receiving a pusher of the engine in order to compress the thrust socket in an inward direction and actuate a pumping plunger in the injector. The thrust socket is forced in a backward direction by a spiral return spring through a retainer cup assembly.

In order to reduce the manufacturing cost of the injector, the thrust socket is held in position in the retainer cup assembly with a flat coiled spring ring that it is not possible to remove easily.

SUMMARY OF THE INVENTION

In view of the situation, and in order to reduce aftersales costs, there is a need for a tooling that permits to remove the spring ring in order to dismount the thrust socket and the present disclosure proposes a removal tool for removing a thrust socket of a pumping injector, said thrust socket being received in a retainer cup and attached to said retainer cup through a coiled flat annular spring ring lying in a plane perpendicular to a main axis of said thrust socket and received in an annular groove of an inner wall of said retainer cup where said removal tool comprises a holding shaft having a first end in a longitudinal axis direction, said first end being provided with a spring ring removal device, said spring ring removal device comprising a stem lying in said longitudinal axis direction and provided at a distal end with a hook for catching said spring ring, said removal device being sized to pass in a tubular gap between a head of said thrust socket and a tubular wall of said retainer cup and sized to be able to rotate about said axial direction when inserted between said head and said wall.

The removal tool is adapted to compress the coils of the coiled flat annular spring ring in order to extract it from a groove in the retainer cup which permits to move the spring ring and thrust socket out of the retainer cup. In realization modes which may be combined or alternate:

A thickness of the stem is adapted to allow the stem to rotate around an axis parallel to axis A in the gap and a thickness of the hook is adapted for catching an end of said spring ring and for grabbing and lifting coils of said spring ring out of said tubular gap through a rotational movement of said stem around said spring ring when said hooked distal end is engaged under said end of said flat spring ring.

The stem may be attached to the holding shaft through a support plate provided with a shoulder cooperating with an annular end surface of said cup for guiding the stem in the tubular gap.

The support plate may be attached on said holding shaft. The support plate may comprise at least one reinforcing rib parallel to said longitudinal axis direction.

The stem may be an extension of the support plate.

Said first end of said shaft may define a push surface for pushing said thrust socket inwards said cup and release tension on said spring ring. The disclosure concerns also a tool kit comprising a removal tool as disclosed and comprising further a flat coil spring mounting tool set comprising:

- an annular guide block having an axial bore with a funnel shaped inner wall and a lower locating collar for securing said annular guide block on a top part of said cup with a reduced diameter wall end of said axial bore positioned flush with an inner surface of said tubular wall; - a tubular spring pusher having a tubular wall provided for entering in the funnel shaped axial bore and entering in the tubular gap between the head of said thrust socket and the tubular wall of said retainer cup.

The disclosure concerns also a process for removing a spring ring and thrust socket with a removal tool of the disclosure, comprising inserting the removal device of the removal tool in the tubulargap between the tubular wall of the retainer cup and the head of the thrust socket, catching an end of an upper coil of the coiled flat annular spring ring with the hook, rotating the removal device around the holding shaft longitudinal axis inside the tubular gap to have the stem pass between the tubular wall and a side of the spring ring at said end, turning the removal tool around the spring ring and lifting coils of said spring ring to remove the spring ring and thrust socket.

The disclosure concerns also a process for repairing an injector comprising the above exposed process for removing a spring ring and thrust socket and comprising further a process for inserting a coiled flat annular spring ring with a mounting tool set disclosed above comprising pushing a coiled flat annular spring ring with the tubular spring pusher in a locking position of the thrust socket through pushing said spring with said tubular spring pusher inside the funnel shaped bore of the guide block for contracting said spring ring and pushing further the contracted spring ring further in said cup into its locking position within said annular groove in said tubular wall.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of exemplary embodiments of the invention will be discussed hereunder in reference to the attached drawings where: Figure 1: a side view with partial cut of an injector according to the disclosure.

Figure2: a cut view of a detail of figure 1;

Figure 3: A perspective view of a removal tool of the disclosure;

Figure 4: a perspective cut view of a detail of the injector with the tool of figure

3 in a working position; Figure 5: a perspective view of the tool of figure 3 in a working position on the top of an injector;

Figure 6: a perspective view with cut of a spring mounting tool set above the top of an injector.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention concerns maintenance of an injector pump as disclosed in figure 1 and known in the art. Such an injector comprises, from the bottom to the top according to the drawing orientation, a nozzle 25 for injecting fuel in an engine cylinder not shown, a nozzle body holding the nozzle and incorporating a solenoid actuator not shown to let fuel enter the nozzle at certain timing when driven by an electric current provide through an electric connector 22.

In the upper part of the injector a high pressure pumping system is provided in order to provide high pressure fuel in an injection circuit of the engine through the high pressure fluid connector 23 with a plunger member 20 which reciprocates in a main injector body 21. The plunger member is cyclically pushed downwardly by a thrust socket 2 actuated by a mechanical pusher not shown of the engine. The mechanical pusher is received in a top recess 2b of the thrust socket. The plunger member 20 and thrust socket 2 are moved back upwards by a return spring 9. A retention assembly made of a retainer cup 3, a spring retainer 8 held together with a retaining ring 26 preloads the return spring 9. The spring retainer 8 is attached to the injector body with tabs 8a pushed over a locating ridge of the injector body.

The retainer cup has a longitudinal bore receiving the thrust socket, such longitudinal bore having a tubular upper part with a tubular wall 3b.

As better seen in figure 2, the thrust socket 2 is held in the retainer cup 3 thanks to a coiled flat annular spring ring 4 which is received in a groove 5 of the tubular wall 3b of the retainer cup 3 as represented in figure 4. It should be noted that there remains a slight play between the interior diameter of the coiled flat annular spring ring 4 and the thrust socket central part which allows compressing the coils of such spring ring inwardly. It also should be noted that the coiled flat annular spring ring (hereafter spring ring) is shown in figures 2 and 4 with approximately 1,8 coils but may comprise two coils or more than two coils.

Contrary to a standard circlip who could be removed with generic tools, the spring ring having several coils makes it impossible to remove with standard clip removal tools.

The spring ring 4 is lying in a plane perpendicular to a main axis A of the thrust socket and received in the annular groove 5 of the inner wall 3b of said retainer cup. A spacer 7 is located under the spring ring 4. A bottom part of the retainer cup comprises a support element 19 for a head 20a of the plunger the support element is made of a circular wall of a hole in the retainer cup forming a socket for the ball shaped head 20a of the plunger 20.

In this configuration, removing the thrust socket 2 above the plunger implies to have an access to the spring ring 4, compress such and remove it in a very constrained area as the diametrical clearance between the thrust socket head 2a and the inner diameter of the spring guide 3b is only 1.3mm with the trust socket in a central position which causes the gap 6 between the retainer cup and the head of the thrust socket to be in the millimeter range.

According to the disclosure, a removal tool 10 shown in figure 3 has a specific shape to be introduced inside the gap 6 to compress the clip from the external diameter to the center with circular movement.

This tool 10 comprises a holding shaft 11 having a first end 11 in a longitudinal axis direction B, said first end being provided with a spring ring removal device 12.

The spring ring removal device comprises a stem 13 lying in said longitudinal axis direction and provided at a distal end with a hook 14 for catching said spring ring 4, said removal device being sized to pass in the tubular gap 6 between the head 2a of said thrust socket and a tubular wall 3b of said retainer cup and sized to be able to rotate about said axial direction when inserted between said head and said wall with said axial direction parallel to said main axis A of said thrust socket.

Back to figure 3, in the example shown, the stem 13 is attached to the holding shaft 11 through a support plate 15 provided with a shoulder 15a which may cooperate with an annular end surface 3a of the cup 3 for guiding the stem 13 in the tubular gap 6 as can be seen in figure 4. The stem 13 is unitary with the support plate 15 but could be attached to such plate.

The support plate 15 is attached on said holding shaft with screws 18 or other means such as rivets and comprises one or more reinforcing ribs 16a, 16b parallel to said longitudinal axis direction.

Figure 4 shows a position of the removal device 12 in the gap with the thrust socket removed for better understanding and figure 5 shows the complete tool with the removal device inserted in such gap 6. A thickness of the stem 13 is adapted to allow the stem to rotate around an axis parallel to axis A in the gap and a thickness of the hook 14 is adapted for catching an end 4a of said spring ring 4.

The removal device 12 can then grab and lift coils of said spring ring out of said tubular gap through a rotational movement of said stem around said spring ring when said hooked distal end is engaged under said end of said spring ring.

In use, the removal tool is positioned on the injector hear with its axis B close to parallel to the main axis A of the injector.

In addition and as seen in figure 5, the first end 11a of the shaft 11 shown in figure 3 defines a push surface for pushing said thrust socket inwards said cup and release tension on the spring ring.

The removal tool 10 with its specific shape is introduced inside the gap to compress the spring ring coils and remove them from their receiving groove with a circular movement around the thrust socket.

By this way, the spring ring is removed and the thrust socket may be removed to be cleaned or replaced.

This tool does not generate any debris or risk to damage the body of the injector.

To provide a complete tool kit, the removal tool is associated with a coiled flat annular spring ring mounting tool set shown in figure 6 and comprising:

- an annular guide block 30 having an axial bore 31 with a funnel shaped inner wall 31 and a lower locating collar 32. The lower locating collar 32 permits to secure the annular guide block on a top part 3a of the cup 3 while the head of the thrust socket enters the axial bore.

The reduced diameter wall end of the funnel shaped axial bore has a same diameter than the inner surface of wall 3b of the cup so in order to be positioned flush with an inner surface of the tubular wall 3b. A the other extremity of the annular guide block, the funnel shape starts with a diameter larger than the diameter of the spring ring 4 and is reduced until it reaches the diameter of the wall 3b of the retainer cup in order to permit compressing said spring ring through reducing the diameter of its coils while pushing it through the funnel shaped bore to reach the diameter of the retainer cup internal diameter and insert such ring in such retainer cup easily.

In alternate designs, the reduced diameter of the funnel shape may be a little smaller than the retainer cup internal diameter to provide clearance and avoid a step between the guide block and cup.

Pushing of the spring ring is done with a tubular spring pusher 33 having a tubular wall 34 provided for entering in the funnel shaped axial bore 31 and the tubular gap 6 between the head 2a of the thrust socket and the tubular wall 3b of the retainer cup 3.

The tubular spring pusher provides insertion of a new spring ring in a locking position of the thrust socket through pushing said spring with said tubular spring pusher 33 inside the funnel shaped bore 31 of the guide block 30 for contracting the spring ring and pushing said contracted spring ring further in said cup until it expands in its locking position within the annular groove 5 in the tubular wall 3b.

The tubular spring pusher is provided with a knurled holding area to provide a good grip for pushing and turning the spring pusher to ease insertion of the spring ring in position.

A process for removing the spring ring and thrust socket comprises inserting the removal device 12 in the tubular gap 6 between the tubular wall 3b of the retainer cup 3 and the head 2a of the thrust socket, catching an end of an upper coil of the coiled flat annular spring ring with the hook, rotating the removal device around the holding shaft longitudinal axis inside the tubular gap to have the stem pass between the tubular wall and a side of the spring ring at said end, turning the removal tool around the spring ring and lifting coils of said spring ring to remove the spring ring 4 and thrust socket 2.

After the thrust socket is removed, a repair process steps may comprise controlling the parts such as thrust socket and plunger, cleaning or replacing such parts. The repair process may end with mounting new or the formers thrust socket and spring ring by positioning said thrust socket in place inside the retainer cup, positioning the annular guide block on the top of the retainer cup, inserting the spring ring in the funnel shaped bore of the annular guide block, pushing the spring ring inside the retainer cup using the spring pusher until the spring ring locks in the groove in the inner tubular wall 3b of the cup 3.

The invention is not limited to the above described example and for example the holding shaft may be knurled or ergonomically shaped without departing from the invention.

LIST OF REFERENCES 1 - Pumping injector

2 - Thrust socket

2a - Head of the thrust socket

2b - Top recess of the thrust socket

3 - Retainer cup

3a - Annular end surface

3b - Tubular wall

3c- Support

4- Coiled flat annular spring ring

5 - Annular groove

6 - Tubular gap

7 - Spacer

8 - Spring retainer 8a- Tab

9- Return spring

10- Removal tool

11- Shaft

11a- first end of shaft

12 - Spring ring removal device

13- Stem

14- Hook

15- Support plate

15a- Shoulder

16a, 16b - Reinforcing ribs

17- Mounting face

18- Mounting screws

19- Support

20- Plunger member

20a- Head of plunger member

21- Injector body

22- Connector

23 High pressure fluid connector

24- Nozzle body

25 - Nozzle

26- Retaining ring

30- Annular guide block

31- Axial bore

31a- funnel shaped wall

32- Lower locating collar

33- Spring pusher

34 - Tubular wall of spring pusher

35- Knurled head