C-shaped clip installation jig

A C-shaped clip 54 is set on the outer periphery of a shaft section 21 of a guide member 2. Part of the C-shaped clip 54 is held between a front edge of a clamp member 3 and the shaft section 21 by gripping a lever 4. In this case, the C-shaped clip 54 is held slantwise to situate the lower end thereof in front. Then, the shaft section 21 of the guide member 2 is inserted into a piston pin installation hole 51 of a piston. In this manner, the lower end of the C-shaped clip 54 is first fitted into an annular groove 53. If the shaft section 21 is further driven to advance while releasing the lever and releasing the holding condition by the clamp member 3, the rest of the C-shaped clip 54 is pushed into the annular groove 53 by a step section between the shaft section 21 and a joint section 22.

TECHNICAL FIELD

The present invention relates to an installation jig for fitting a C-shaped clip into an annular groove formed in a hole for a workpiece.

BACKGROUND ART

A piston is provided with a piston pin to which a small end of a connecting rod is connected. To prevent the piston pin from coming off, a C-shaped clip is fitted into an annular groove of a hole in which the piston pin is installed.

The C-shaped clip fitting operation is manually conducted mainly using long-nose pliers and the like. Since the operation is inefficient, various devices or jigs are proposed to improve the situation.

Patent Document 1 proposes an automatic fitting device comprising an ejecting cylinder, a positioning cylinder, and a fitting cylinder. According to this automatic fitting device, C-shaped clips held within a holder are slantwise pushed into a cylindrical member, one by one, in a reduced diameter condition by the ejecting cylinder. Subsequently, the cylindrical member is lowered by the positioning member to touch a piston, wherein the clip is caused to engage the inside of an annular groove by the fitting cylinder.

Patent Document 2 proposes a device in which a receiving shaft is inserted into an insertion hole for a piston pin, a clip catcher is caused to hold a clip, the clip catcher and a pusher are caused to integrally come close to a piston, the clip held by the clip catcher is transferred to the receiving shaft with a slope, wherein the clip is pushed into the insertion hole by the pusher.

Patent Document 3 discloses a jig in which when a clip is fitted into an annular groove formed in a deep section of a hole for a workpiece, the clip is set on a tapered inlet section of the hole. In this condition, the jig which is concentrically, slidably and integrally formed with a first punch and a second punch is caused to contact the tapered inlet section of the hole, wherein the clip is first pushed into the hole in the reduced diameter condition by the outside first punch and the clip is then pushed into the annular groove formed at the deep section by the second punch.

According to the fitting device comprising the ejecting cylinder, the positioning cylinder, and the fitting cylinder disclosed in Patent Document 1, it is possible to automatically install the C-shaped clip into the annular groove. However, the device becomes large and it becomes complicated to cope with the change of device.

In the device disclosed in Patent Document 2, it is necessary to operate two jigs of the receiving shaft and the pusher separately. Such a separate operation is troublesome so that it takes time to install the clip on the clip catcher.

In the jig disclosed in Patent Document 3, since the clip must be correctly set on the tapered inlet section of the hole of the opposite member, workability is not good. Further, usability is not good because the jig cannot be used in the case where the inlet section of the hole is not tapered.

DISCLOSURE OF THE INVENTION

It is therefore an object of the present invention to provide an improved C-shaped clip installation jig which can solve the problems stated above.

In order to attain this object, according to the present invention, a C-shaped clip installation jig comprises a grip section adapted to be gripped by an operator, a guide member which is provided on the front edge of the grip section and can be inserted into the hole for a workpiece, and a clamp member which is rotatably secured to the grip section and is adapted to hold down part of the C-shaped clip between the outer periphery of the guide member and the clamp member by the operation of a lever. With this construction, even a person with no experience can surely install the C-shape clip in the shortest time.

In particular, by detachably securing the guide member to the grip section, it is possible to easily cope with the change of installation jigs if guide members of a different size are prepared in advance.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.FIG. 1is a general view of a C-shaped clip installation jig according to the present invention.FIG. 2is an exploded view of the C-shaped clip installation jig.FIG. 3is a top view of a grip section of the C-shaped clip installation jig andFIG. 4is a top view of a lever.

The installation jig consists mainly of a grip section1, a guide member2, a clamp member3, and a lever4.

The grip section1is made of a pipe member. Slip resistance by a knurling process is applied on the outer periphery of a base section of the grip section1. An attachment11is secured to the front end of the grip section1and the top surface of the front section is axially provided with a slit12into which the clamp member3is inserted. Formed on the side thereof is a pin insertion hole13for rotatably supporting the clamp member3.

The guide member2comprises a shaft section21of which the front edge is pointed to be inserted into a hole for a workpiece of a piston and the like and a joint section22detachably secured to the attachment11. In this embodiment, three kinds of guide members2are prepared. These three kinds of guide members2have shaft sections21of which the length and diameter are different, and common joint sections22.

The clamp member3is made of a plate member which is angled when seen from the side. The front edge of the clamp member3becomes thin and is provided with a depression31into which a clip is fitted. Formed on the central section of the clamp member3is a pin insertion hole32for rotatably supporting the clamp member3relative to the grip section1. The lower section of the clamp member3is formed with an installation hole33for the lever4.

The clamp member3is spring-biased by a spring (not shown) in the closing direction, that is, in such a direction that the front edge thereof contacts the upper surface of the guide member2.

With this arrangement, steps for installing a clip into an annular groove of a piston pin installation hole will now be described with reference toFIG. 5andFIG. 6which is a view taken along line A-A ofFIG. 5. InFIG. 5, a piston pin52is installed in a piston pin installation hole51and a C-shape clip54is fitted into one of annular grooves53and53formed on both ends of the piston pin installation hole51.

As shown inFIG. 5, the C-shaped clip54is set on the outer periphery of the shaft section21of the guide member2and part of the C-shaped clip54is held between the front edge of the clamp member3and the shaft section21by gripping the lever4. In this case, the C-shaped clip54is held slantwise to situate the lower end thereof in front.

Subsequently, the shaft section21of the guide member2is inserted into the piston pin installation hole51. In this case, the lower end of the C-shaped clip54is first fitted into the annular groove53. When the shaft section21is further advanced while releasing the lever4and releasing the holding condition by the clamp member3, the rest of the C-shaped clip54is pushed into the annular groove53by a step section between the shaft section21and the joint section22.

As shown inFIG. 6, part of the annular groove53is formed as a notch section53a. When the piston is disassembled, it is necessary to remove the C-shaped clip54. This notch section53aserves to allow the front edge of long-nose pliers to enter. In the present embodiment, it is possible to not only install the clip, but also to remove it. Namely, when the shaft section21of the guide member2is inserted into the innermost recess of the piston pin52, the front edge of the clamp member3is caused to correspond with the notch section53ato engage part of the C-shaped clip54fitted into the annular groove53by strongly gripping the lever4, wherein the shaft section21is extracted in such a condition.

According to a conventional method, the clip is removed using pliers and the like. This leads to damage or deformation of the clip and as a result, there is a disadvantage that it is difficult to remove the clip. According to the present invention, removal of the clip can also be easily performed.

Further, if the open end of the C-shaped clip54agrees with the notch section53a, it is not possible to remove the C-shaped clip when disassembled. However, according to the present invention, the open end of the C-shaped clip can be situated in a fixed position of the annular groove53.

In the above-mentioned embodiments, examples are explained, in which an operator sets the C-shaped clips on the shaft section21of the guide member2, one by one. Examples in which the C-shape clips are automatically installed will now be explained with reference toFIGS. 7 through 11.FIG. 7is a general view of a clip-loading (installation) device provided with a C-shaped clip installation jig and a separation device according to the present invention.FIG. 8is a view taken along line B-B ofFIG. 7.FIG. 9is a front view of a separating plate forming part of the separation device andFIG. 10is a cross-sectional view taken along line C-C ofFIG. 9.FIG. 11is a rear view of the separating plate forming part of the separation device.

A clip-loading device comprises an installation jig set device6and a separation device7. The installation jig set device6is provided so that a rail62is disposed parallel to a base61, the rail62is caused to engage a mounting base63for mounting and securing the C-shaped clip installation jig on the rail62, and the mounting base63is designed to advance or retreat relative to (to and from) the separation device7.

On the one hand, the separation device7is provided in such a manner that a rail72is disposed parallel to a base71, a guide pipe73is disposed above and parallel to the rail72, and the rail72is provided with a movable body74. A constant force spring76is provided between the movable body74and a support plate75secured to the base71.

Further, as shown inFIG. 8, a V-shaped guide plate77is secured to the front edge of the support plate75. The shaft section21of the guide member2is mounted on the guide plate77for alignment.

One the one hand, a group of C-shaped clips54is installed on the outer periphery of the guide pipe73. A ring member78is slidably disposed on the outer periphery of the guide pipe73on the rear side of the group of C-shaped clips54to engage part of the movable body74. In this manner, the biasing force of the constant force spring76is applied to the group of C-shaped clips54through the movable body74and the ring member78to spring-bias the group of C-shaped clips54on the right side of the figure. The far right C-shaped clip54of the group of C-shaped clips54touches the separating plate80which is adapted to move vertically by a cylinder unit81firmly secured to the base71.

The shape of the separating plate80is explained with reference toFIGS. 9 through 11.FIG. 9is a front view of the separating plate andFIG. 10is a cross-sectional view taken along line C-C ofFIG. 9.FIG. 11is a rear view of the separating plate forming part of the separation device. The separating plate80is formed as a rectangle when seen from the front and is provided at the center with an oval opening82. The rectilinear right and left sides of the inner periphery of the opening82are provided with a step section83and a wedge section84.

FIGS. 12(a) through (c) are views explaining the operation of the separation device.FIG. 12(a) shows the condition in which the far right C-shaped clip54of the group of C-shaped clips54contacts the step section83of the separating plate80and stops under the influence of biasing force of the constant force spring76.

If the separating plate80is lowered from this condition by the actuation of the cylinder unit81, the wedge section84is driven between the far right C-shaped clip54and the subsequent C-shaped clip54as shown inFIG. 12(b) and as a result, the upper section of the far right C-shaped clip54is separated to fall down on the right side. If the separating plate80is further lowered, the far right C-shaped clip54is completely separated as shown inFIG. 12(c).

Thus, the separated C-shaped clip54is held by the front edge of the clamp member3for preparation of the subsequent clip installation. By improving the front edge shape of the clamp member3, it is possible to separate the C-shaped clip54and to allow the upper end of the C-shaper clip54to enter under the clamp member3at the same time.

INDUSTRIAL APPLICABILITY

The C-shaped clip installation jig according to the present invention can be effectively used in such a process where the clip installation is carried out by conventional pliers.

According to the invention, gripping and releasing of the clip can be performed only by the operation of a lever. Since such an operation can be performed with only one hand, operationality is extremely good and it is not affected by the skillfulness of the operator. Number of parts used can also be reduced to make the jig lightweight. Thus, the jig is costwise advantageous and production can also be easily performed.

Further, the clip installation jig according to the present invention can also be used to remove the clip from the existing piston and the like.