A DEVICE FOR MOUNTING ELASTIC ANNULAR DETAILS ONTO MACHINE PARTS

Abstract: A device for mounting elastic annular details such as sealing rings to machine parts and similar objects which have an axis (A) of symmetry and a free end (24), comprises means (16) for positively guided application of the elastic detail (25) onto said object (19), said means being supported so as to be movable in a plane containing said axis (A) of symmetry of the object (19) as well as in a path around said axis and adapted to engage the inner side of the detail (25) at only a portion of the circumference. For making the device easily usable for various sizes of details (25) and objects (19), the invention suggests that the guide means is made as a radially movable hook (16) adapted to displace the detail (25) radially a distance at the point of engagement and when moved in the direction of the axis (A) of symmetry as well as moved angularly therearound to entrain said detail (25) to the desired position along the length of the object, and in that a retaining means (12) is adapted at the initial revolution of the rotary movement of the guide means (16) to be brought into engagement with the free end (24) of the object (19) for retaining the detail (25) and force the same to climb said object (19).

Description: A Device For Mounting Elastic Annular Details Onto Machine Parts The present invention refers to a device for mounting elastic annular details such as sealing rings to machine parts and similar objects having an axis of symmetry and a free end, said device comprising means for posi- tively guided application of the elastic detail onto said object, said means being supported so as to be movable in a plane containing said axis of symmetry of the object as well as in a path around said axis and adapted to engage the inner side of the detail at only a portion of the circumference. A device of this kind is known from US-A 1968640. When assembling industrial products, elastic details often are used which have low or restricted form stabi¬ lity, such as rubber rings, plastic rings, sealings etc. This kind of details cause problems in the assemb¬ ly, particularly when the same is to be automized. In some cases, said problems can render the automation impossible and in other cases make the same non-economi¬ cal. The principles used today in automatic assembly and mounting most often rely on a specially-designed tool which fits an article of a particular size. In some cases the part being dependent on the dimension con¬ stitutes only a certain portion of an assembly appa¬ ratus. To use tools which are dependent on dimensions implies several drawbacks, such as great tool costs, great tool-changing times, extensive work for introduction of a new detail etc. The above-stated US patent specifica¬ tion is a typical example of said fact, since for each size of valve seat a particularly adapted tool has to be used. Furthermore, from US-A 3177569 is also known a tool for positively mounting a handle onto the neck of hollow articles such as bottles. In this device the reaction forces from the operative guide means are transferred to a support acting against the inner surface of the bottle neck and hence this device cannot be used with non-hollow articles and requires similarly to the afore¬ mentioned tool a particular dimensioning for each artic¬ le size. The object of the present invention now is to provide a device of the above-stated kind which allows that one and the same size of the device can be used for mounting details onto objects of several different sizes and which furthermore allows that the detail can be moved a greater distance along the object in the direction of the axis of symmetry thereof. According to the invention this object is substantially achieved in that the guide means is made as a radially movable hook adapted to displace the detail radially a distance at the point of engagement and when moved in the direction of the axis of symmetry as well as moved angularly therearound to entrain said detail to the position along the object, and in that a retaining means is adapted at the initial revolution of the rotary movement of the guide means to be brought into engage- ment with the free end of the object for retaining the detail and force the same to climb said object. Owing to the invention a device is now provided which makes the mounting of elastic annular details onto machine parts and similar objects rapid and easy. Furthermore, the device also can be easily adjusted for adaptation to various sizes of the details and objects. By way of example the invention will be further describ- ed below with reference to the accompanying drawings in which Fig. 1 is a side elevational view illustrating an embodiment in principle of a device according to the invention. Fig. 2 is a plan view of an object with a detail in the form of a sealing ring climbed thereon, Figs. 3 - 5 are side views of a portion of the device together with the object in various moments of the application of the detail, i.e. the sealing ring, onto the object. Fig. 6 is a side view of another embodiment of the inventive device and Figs. 7 - 10 are side views of various embodiments in principle of the very hook- shaped guide means. As is evident from Figs, l - 3 of the drawings, a mount¬ ing device 10 according to the invention consists of a tool 11 and a retaining means 12. The tool 11 comprises an elongated shank 13 which at one end 14 is secured to the tool 11, preferably at right angles thereto. The shank 13 is adapted to be secured under the intermedia¬ tion of the slideable tool 11 eccentrically in relation to a suitable rotatable element 17 so as to be located at a selected radial distance from the axis A of rota¬ tion of the element. The tool 11 is adapted to rotate about an object 19, the center axis of which coincides with the axis A of rotation of the tool. The object has a free end 24. The shank 13 supports at its other end 15 a guide means which according to the invention is made as a hook 16. The retaining means 12 comprises an elongated shank 21, at one end resiliently secured in a suitable holder 22. From a rotational point of view, the retaining means 12 is stationary in relation to the axis A of rotation of the tool. When using the device according to the inven¬ tion, it is intended that after an elastic annular detail 25, such as a sealing ring or the like, has been inserted manually or automatically in the hook 16, the tool 11 is to carry said detail or ring against the free end 24 of the object without rotation. After that the retaining means 12 is adapted to be brought into engagement with its free end against the free end 24 of the object, so as to prevent the applied detail or ring 25 from slipping off from the object. The tool 11 with the hook 16 supported thereby, which engages the detail or ring 25, is then brought to rotate an initial revolution, during which the hook 16 slides along the inner side of the detail or ring 25 and ex- pands the same locally in radial direction a distance sufficient for making the ring climb the free end 24 of the object around the full circumference thereof. After that, the retaining means 12 is removed. By a suitable movement of the rotary element 17 in the direction of the rotational axis A thereof the tool 11 with the hook 16 is brought to move the detail or ring 25 along the outer surface of the object 19 to an in¬ tended position, such as the ring groove 22 according to Fig. 4. The major advantage of the inventive device is that the guide means or hook 16 engages the detail 25 at a posi¬ tion which constitutes a small portion of the circumfer¬ ence, such that the stretching of the elastic annular detail 25 will be limited and the risk for damages thereon are eliminated. In the drawings the object 19 has been illustrated standing upright but this does not constitute a limitation but the object together with the element 17 might as well occupy an inclined position or even be horizontal. By selecting a suitable combina¬ tion of the orbital speed of the guide means 16 around the object 19 and the movement in the longitudinal direction thereof many different forms of details can be mounted onto various types of objects. Tests have shown that it is possible to transfer details over shoulders, chamfers etc. Test also have shown that it is possible to mount de¬ tails onto objects having other cross-sectional shapes than circular, such as oval and rectangular cross-sec¬ tions. The expression "elastic annular details" is in- tended in the present connection to include rings of rubber or plastic, so-called O-rings, spring-reinforced rubber details etc. An important advantage of the device according to the present invention ought to be obvious from the above- stated description, namely the fact that the same tool 11 and guide means 16 can be used in connection with several different sizes of details for being mounted onto objects of different sizes. The adjustment of the tool 11 so as to place the guide means 16 at a desired distance from the object in view of the dimensions thereof and of the detail is fast and easy to carry out. By the fact that the elongation of the detail is small, the device can be used for mounting details hav¬ ing great as well as small elasticity. The above-stated advantages are of particular importance when the device is to be used in connection with robotized assembly. In Fig. 6 of the drawings has been illustrated a side elevational sketch of another embodiment of the mounting device according to the invention. Similar parts of the device as in the first embodiment described above, have been provided with the same reference numerals. In Figs. 7 - 10 there have been illustrated detail views of various examples of closeable versions of the hook 16 which now are to be described. Advantageously the hook 16 namely can be made like a snap hook having a movable spring-biased pin 18 as closing member. The position of the pin defines an open and a closed state of the hook. In this case the hook 16 is oriented relative the object 16 such that the pin is facing the latter. The hook can be opened by means of a lifting arm 20, either manually or preferably automatically by means of e.g. a pneumatic cylinder. In Fig. 8 an alternative embodiment is disclosed in which the hook 16' is formed as a hook-like curved member and in Fig. 9 the hook 16' * is constituted solely of a neck 18 " facing away from the object 19. Finally, in Fig. 10 is illustrated a further alternative embodiment, in which the hook 16* • ' is formed as a cavity open in the direction of the axis A of the object 19 and adapted to accomodate the elastic annular detail 25 and then be closed by mans of a pin 18* • ' . Said pin is movable at right angles to the axis A of the object 19 and the element 17. As is evident from Fig. 6, the retaining means 21, which at one end is secured to a holder 32, further¬ more can be provided with an extending arm 23 at its other end. Said arm forms in its operative position engaging the free end 24 of the object 19 an acute angle of between 10 and 80° and preferably about 45° with the last-mentioned rotational axis A. It is to be noted that the friction between the object 19 and the annular elastic detail 25 always has to be greater than between the guide means 16 and the detail.

Claims: C l a i m s 1. A device for mounting elastic annular details such as sealing rings to machine parts and similar objects having an axis (A) of symmetry and a free end (24), said device comprising means (16) for positively guided application of the elastic detail (25) onto said object (19) , said means being supported so as to be movable in a plane containing said axis (A) of symmetry of the object (19) as well as in a path around said axis and adapted to engage the inner side of the detail (25) at only a portion of the circumference, c h a r¬ a c t e r i z e d i n that the guide means is made as a radially movable hook (16) adapted to displace the detail (25) radially a distance at the point of engage¬ ment and when moved in the direction of the axis (A) of symmetry as well as moved angularly therearound to entrain said detail (25) to the desired position along the object, and in that a retaining means (12) is adapt¬ ed at the initial revolution of the rotary movement of the guide means (16) to be brought into engagement with the free end (24) of the object (19) for retaining the detail (25) and force the same to climb said object (19). 2. A device according to claim 1, c h a r a c t e¬ r i z e d i n that the hook (16* ;16* ' ;16' * ') is close- able bymeans of amovable closure member (18;18* ' ,18* ' ') .

Inventors: ARNSTROEM ANDERS, LANGBECK BJOERN, ARNSTROEM, ANDERS, LANGBECK, BJOERN
Applicants: INST VERKSTADSTEK FORSK IVF, INSTITUTET FOER VERKSTADSTEKNISK FORSKNING (IVF)
Application year: 1991
Main classification: B23P19
IPC codes: B25B27