Fixation element and method for its production

DESCRIPTION

The present invention relates to fasteners for mounting a first component in a second component so that it was isolated from vibrations, and for this purpose, the fastener includes a seat plate that are arranged at a certain distance from the one of the other and having protruding coupling elements that are intended to penetrate one or more corresponding holes formed in each component, so that the two components rest stably against the seat plates.

The assembly of a first component in a second component so that it is isolated from vibrations generally implies the use of rubber elements, which are frequently assembled by means of screws, nuts, washers and sometimes even with a separation sleeve that passes through them. . The use of a certain number of components gives rise to problems. For example, the various components create more work regarding distribution and storage. In addition, the assembly is more difficult and time-consuming, particularly if the space around the two components is reduced. Furthermore, the assembly must normally be carried out with an exact tightening movement, so that the elastomeric element is not subjected to a compression greater than that which is admissible.

These problems occur, for example, when mounting a refrigerant compressor in a refrigerator or freezer. Vibrations from this compressor can be transmitted to the refrigerator or freezer frame and result in a resonance noise. Vibrations may also deteriorate refrigerant transport tubes and other components of the refrigerator or freezer. Therefore, it is considered that the assembly of the compressor in a refrigerator or freezer is very important with respect to the quality of the finished product. As a result of high quality demands, in a real case the compressor assembly may take approximately two to three minutes. This means that the compressor assembly constitutes an important bottleneck in the production of refrigerators and freezers.

The verification of plastics fixing elements has been carried out, which have been molded in one piece and have been provided with a vibration damping design thanks to parts of reduced material thickness. These fasteners have a relatively mediocre efficiency to dampen vibrations and therefore have failed to meet quality requirements.

Conditions similar to those described above also apply to other manufacturing lines, such as the assembly of compressors in heat pumps and the assembly of various components in vehicles.

An object of the invention is to provide a fixing element by means of which the inconveniences described above can be avoided. Another object of the invention is to produce these fixing elements in an efficient manner.

A fixing element according to the invention was characterized in that the quick coupling elements form an integral part of each seat plate, and because the plates are mutually connected by means of a bridge-shaped part made of elastomeric plastics material. Thanks to this fixing element it is possible to join the two components with one another in a way that ensures the isolation of vibrations in an extremely short period of time.

According to an advantageous example of embodiment of the invention, the elastomeric part is molecularly attached to each seat plate. In a variant, the elastomeric part can be mechanically attached to each seat plate by means of bridges of elastomeric material that extend through holes formed in each seat plate. Both methods allow to obtain an effective bond between a logical plagistic material and an elastomeric vibration isolation material.

At least one sleeve-shaped element extends from the first seat plate and a one hole hole, coaxially with respect to the longitudinal axis of the element, in the second seat plate, the free space being between the edge of the hole and the sufficient element to avoid mutual contact under normal operating conditions. This provision ensures transport reliability that prevents damage from occurring, even if the components are in an abnormal position.

According to another advantageous example of embodiment of the invention, at least one of the quick coupling elements was provided with a locking pin that was coaxially formed with this element and which, after the assembly of each component, can be introduced into the coupling element to block it. Thanks to this arrangement it is possible to give the quick coupling element smaller dimensions, without reducing its strength.

A method of production of fixing elements according to the invention was characterized in that the seat plates are formed in one piece using a first casting mold, so that they are connected at least by a breakable bridge, because said piece is located in a second casting mold consisting of two halves, because the two halves of the mold are pushed together axially, axially moving a seat plate relative to the other, so that the bridge is broken, and because an elastomeric plastic material is cast into the mold between the two seat plates. The vent obtained thanks to this production method is that it is only necessary to move a piece from the first mold to the second casting mold.

The two halves of the second casting mold are conveniently pushed towards each other until the desired distance between the two seat plates is obtained. In this regard, the travel distance of the two seat plates can be modified by a diver nucleus that can be displaced axially in the mold, such

017 221 so that fixing elements with different desired distances between the two seat plates can be produced in the same molding device.

According to an advantageous embodiment of the method according to the invention, the second casting mold is divided in line with the first seat plate. Thanks to this design of the second casting mold, the separation of the two seat plates can be done automatically by bringing the two molding devices to each other.

On the other hand, said seat plate can be provided with a central hole for a sleeve-shaped element protruding from the second seat plate. This allows, through the first molding device, to pass through the first seat plate and move the second plate axially, so that the parts acting as a bridge are broken and so that the required distance between the two is obtained seat plates

The characteristics mentioned in the foregoing as well as other features of the invention will be described in the following in more detail, referring to the attached drawings in which:

Figure 1 is an end view of a fixing element according to a first embodiment of the invention,

Figure 2 is a side view of the fixing element illustrated in a mounting position between two components,

Figure 3 is a sectional view taken along line III-III of Figure 1,

Figure 4 is an end view illustrating the fixing element during manufacturing, between a first and a second casting operation,

Figure 5 is a sectional view taken along the line VV of Figure 4,

Figure 6 depicts, by means of an open view, a casting mold for carrying out the second casting operation,

Figure 7 is an end view of a fastener in accordance with a second embodiment of the invention, and

Figure 8 is a sectional view taken along line VIII-VIII of Figure 7.

The fixing element illustrated in Figures 1-3 includes two circular seat plates 10 and which are arranged in parallel, the first having a diameter smaller than the second. The two plates 10, 11 are held together by a part 12 of elastomeric material.

The seat plate 10 is provided with a relatively narrow quick coupling element 13 projecting in straight angles with respect to the side of the seat plate 10 which is remote from the plate 11. A cylindrical locking pin 14 is arranged in the extension of the quick coupling element 13 in such a way that it can be introduced axially into an internal coaxial channel 15 formed in the quick coupling element 13. The seat plate 10 is provided, on the side opposite to the quick coupling element 13 of a sleeve section 16 which is coaxial to the longitudinal direction of the channel 15 and which extends through a central hole 17 formed in the plate wider seat 16. The hole 17 is wider enough than the sleeve section 16 so that in normal operating conditions contact between the edge of the hole and the sleeve section is prevented.

The seat plate 11 is provided with a relatively wider coupling element 18 protruding in straight angles with respect to the side of the plate 11 that is remote from the plate 10.

Figure 2 represents the fixing element in a mounting position between a first component 19, for example a part of the refrigerator frame, and a second component 20, for example a fixing plate of a refrigerant compressor. The locking pin 14 is located inside the coupling element 13 and tends to separate the flexible bridges 13a that form the quick coupling element 13. At the same time, the locking pin 14 reinforces the most sensitive part of the quick coupling element, that is to say the neck section located at the transition point with the seat plate 10. Figure 2 represents a possible use position for the fixing element when the refrigerator is arranged vertically. However, if the refrigerator is transported in a horizontal position, there is a risk that the elastomeric part 12 of the fixing element will be subjected to abnormal stresses, for example shear forces. The sleeve section 16 is intended to prevent these forces from appearing.

The fixing element described above is prepared for assembly, and in this respect the necessary number of fixing elements are firmly pressed with their quick coupling elements 18 into mounting holes formed in the first component 19 or 20. Next, the opposite rapid coupling elements 13 are placed in mounting holes formed in the second component. Finally, the locking pin 14 is inserted into each quick coupling element.

13. Normally, this assembly takes place in approximately 10 to 15 seconds when four fasteners are used. Therefore the time economy is very important in comparison with conventional assembly methods.

The embodiment of the fixing element described above will be described schematically in relation to Figures 4-6. In this case, the piece 21 represented in Figures 4 and 5 is molded under pressure to form a piece of rigid plastic, for example polyamide, in which the two seat plates 10, 11 are connected by bridges 22 and the pin Lock 14 is connected to the quick coupling element 13 in the manner described above.

The piece 21 is placed in a second casting mold consisting of two halves 23, 24 and is divided in a line with the outer part of the seat plate 11. When the two halves of the mold are joined, the two seat plates 10 , 11 move axially away from each other, until the bridges 22 are broken and a

017 221 predetermined distance between the plates. The fixing of the two separate parts in the molding device is carried out, inter alia, by means of a certain number of protruding pins 23a in the middle 23 of the mold and a sleeve 24a in the middle 24 of the mold. The space 25 that remains in the molding device is filled, for example, with a thermoplastic elastomer. After hardening of this elastomer, the fixing element can be removed from the molding device and constitutes the finished product.

The height of the fixing element can be modified by increasing or reducing the distance between the two seat plates. It is possible to design the mold halves 23, 24 with movable parts in axial direction, which allows the appearance of the elastoomer part to be modified.

In the second embodiment of the invention shown in Figures 7 and 8, the same piece 21 described in accordance with the first embodiment is used. However, the elastomeric part 12 has been molded in the form of a crushed tube so that it acquires an oval shape, the two flat sides of the oval forming the bases for the seat plates 10, 11. The semicircular parts of the oval tube increase the elasticity of the elastomeric part 12. This design of the elastomeric part 12 makes it very easy to modify the shape of the elastomeric part for certain applications and also allows to use a wide spectrum of materials endowed with different elastomeric properties. The elastomeric part 12 is provided with holes 26 for the protruding pins 23a, which have already been described in conjunction with the first embodiment.

In the two embodiments illustrated in the drawings, the elastomer material extends around both sides of the seat plates. This allows to produce a mechanical connection between the hard plastics and the elastomer, because the plates are provided with a certain number of small holes that can constitute bridge spaces for the elastomer material. In a variant, a molecular bond between hard plastid and elastomer can be achieved.

The invention is not limited to the embodiment described above, and several modifications can be devised without departing from the scope of the following claims. For example, the appearance of the elastomeric part can be modified in many ways, in order to ensure maximum damping at different frequencies. Each seat plate can be equipped with a quick coupling element.

Described the object of the present invention in its different parts, it is declared that what constitutes the essentiality of it, is what is specified in the following:

017 221