Retaining Device Of A Tool Cotter For A Percussive Demolition Apparatus

Abstract

The tool mounted in a body of an apparatus is retained by a cotter engaging inside a notch of the tool, the cotter being engaged in a borehole of the body. The area of the body containing this borehole for engagement of the cotter is equipped with a covering ferrule. This ferrule is provided for occupying a first position in which it at least partially occludes the borehole and a second position in which the borehole is cleared for enabling the cotter to be inserted or removed.

Description

In any case, the invention will be well understood with the aid of the following description, with reference to the appended schematic drawing representing, as nonlimiting examples, several embodiments of this device.

FIGS. 1 and 2 are two views in cross section of two devices illustrating the prior art.

FIG. 3 is an exploded view in perspective of a percussive demolition apparatus fitted with the device according to the invention.

FIGS. 4 and 5 are two views in cross section and on an enlarged scale of this device along the line IV-IV of FIG. 3, respectively in the uncovered position and in the locked position of the cotter.

FIG. 6 is a view in perspective on an enlarged scale of another ferrule.

FIG. 7 is a view in cross section, similar to FIG. 5, of an apparatus fitted with the ferrule of FIG. 6.

FIG. 8 is a view in perspective of an apparatus fitted with a ferrule that can be moved in translation.

FIG. 3 represents an apparatus 20 comprising a body 22 of substantially cylindrical cross section terminating at one of its ends in a plate 23 for attachment to a support. In the end of the body opposite to that fitted with the plate 23, a bore 24 opens, designed for the passage of a tool 25 comprising, in its rear zone, a notch 26. In the body 22 a transverse bore 27, offset relative to the axis of the body 22, is arranged, this bore emerging in a peripheral groove 28 comprised in the body. The bore 27 serves for the engagement of a cotter 29 for retaining the tool, by the engagement of the cotter in the notch 26 of the tool 25.

The groove 28 is designed for the mounting of a ferrule 30, of a width substantially matching that of the groove, made of a material with a high elastic limit, such as spring steel. The length of the ferrule is less than the perimeter of the body, in order to arrange between the two ends of the ferrule a slot that is wider than the diameter of the bore 27 receiving the cotter 29.

In practice, when the cotter is inserted, the ferrule is pivoted into the position shown in FIG. 4, uncovering the bore 27, and allowing the cotter to be inserted or removed. On the other hand, while the apparatus is working, the ferrule is pivoted into the position of FIG. 5 to close off the bore 27.

FIG. 6 represents a ferrule 30 similar to that previously described, one end of which is furnished with a finger 32 protruding on its inner face, this finger 32 being designed to engage in a recess 33 made in the outer wall of the body of the apparatus in the closed position of the ferrule, as shown in FIG. 7.

In the embodiment shown in FIG. 8, the ferrule 30 consists of a split ring, which can be moved in translation on the body 22 to uncover, as shown in the drawing, the bore 27 designed to receive a cotter 29. In the working conditions of the apparatus, the ferrule 30 is housed in the groove 28.

It should be specified that the term “body” that has been used previously in the description must be taken in the broad sense, and may just as well relate to the body of the apparatus or to a casing surrounding the body, insofar as the apparatus is more complex and comprises a body designed for the guidance of the tool and the hydraulic actuation of the latter, and an outer casing serving as a support for the assembly.

As emerges from the foregoing, the invention provides a great enhancement to the prior art, by providing a device of simple structure, perfectly incorporated into the apparatus and not risking being damaged during the operation of the latter, while having a moderate cost price.

It goes without saying that the invention is not limited only to the embodiments of this device that are described hereinabove as examples; on the contrary, it covers all the variants thereof.

Claims

1. A tool cotter retaining device for a percussive demolition apparatus, in which the tool mounted in a body of the apparatus is retained by a transverse cotter engaged in a notch of the tool, the cotter being engaged in a bore of the body, wherein the zone of the body comprising the bore for the engagement of the cotter is fitted with a covering ferrule, this ferrule being arranged to occupy a first position in which it at least partially closes off the bore and a second position in which the bore is uncovered, to allow the cotter to be inserted or removed.

2. The device as claimed in claim 1, wherein the ferrule is made of a material with a high elastic limit.

3. The device as claimed in claim 1, wherein the ferrule is made of spring steel.

4. The device as claimed in claim 1, wherein the body of the apparatus comprises a peripheral groove, into which the bore of the cotter opens, and which serves for the positioning and guidance of the ferrule on the body.

5. The device as claimed in claim 1, wherein the body of the apparatus comprises raised elements, such as ribs or pins serving to guide the ferrule.

6. The device as claimed in claim 1, wherein the ferrule is of cylindrical shape and consists of a cylinder closed on itself in which an opening is made with a diameter at least equal to the diameter of the bore of the body designed for the cotter to pass through.

7. The device as claimed in claim 1, wherein the ferrule is of generally cylindrical shape and consists of a split ring.

8. The device as claimed in claim 7, wherein the ferrule comprises a finger, turned on its inner face, designed to engage in a recess of the body, to lock the ferrule in position covering the bore of the body designed for the cotter to pass through.