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(11) | EP 0 927 585 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Device for clamping a stem to the traction mandrel of a riveting tool |
| (57) In a device for clamping a stem to the traction mandrel of a riveting tool, the traction
mandrel has a traction sleeve (11) loosely fitted in the enclosing sleeve (12) and
mutually secured with the enclosing sleeve against axial shifting and turning. Between
the enclosing sleeve and the peripheral recess in the traction sleeve (11) there is
a compression spring (10). The traction sleeve (11) has an inner thread, onto which
is screwed the stem (1), whose collar has at least one flattened plane on its outer
circumference corresponding to an inner peripheral surface of the adjacent part of
the enclosing sleeve (12). The device is fitted together with the traction mandrel
(13) in the nozzle (5) of the riveting tool, wherein the nozzle has a passage opening
in the area of the enclosing sleeve (12). Without the use of a tightening instrument
as for example a key, it is possible to change easily and very quickly the mandrels
for rivets in the riveting tool. |
Field of the invention
[0001] The invention involves a device for clamping a stem to the traction mandrel of a riveting tool.
Description of the prior art
[0002] At the present time mandrels for nut and screw rivets in riveting tools are tightened by turning them with a key to their frontal stop either at the lock-nut or the recess on the traction mandrel of the riveting tool. Tightening is necessary in order to prevent their accidental release (unscrewing) from the traction mandrel. This tightening operation requires a certain amount of time and an implement (a key) all of which lengthens the time required to replace the mandrels.
Summary of the invention
[0003] The above disadvantages are eliminated by the arrangement, according to this invention, of a device for clamping a stem to the traction mandrel of the riveting tool. The basis of the invention lies in the fact that the traction mandrel has a traction sleeve loosely fitted in the enclosing sleeve and mutually secured with the enclosing sleeve against axial shifting and turning; between the enclosing sleeve and the peripheral recess in the traction sleeve there is a compression spring. The traction sleeve has an inner thread into which is screwed the stem, whose collar has at least one flattened plane on its outer circumference corresponding to an inner peripheral surface of the adjacent part of the enclosing sleeve. The device is fitted, together with the traction mandrel, in the nozzle of the riveting tool, the nozzle having a passage opening in the area of the enclosing sleeve.
The compression spring is fitted against a lock-nut screwed to the traction mandrel.
The securing of the traction sleeve and the enclosing sleeve against mutual axial shifting is effected by means of a safety ring, fitted in a recess of the enclosing sleeve and resting against the stepped end of the traction sleeve.
The passage opening in the nozzle is covered with a sliding covering sleeve, between which and the nozzle is a protective flexible O-ring, situated on the side of the passage opening in the direction of the outer end of the nozzle. The device is provided with a stop to prevent the covering sleeve slipping from the nozzle. The traction sleeve can be an integral part of the traction mandrel.
[0004] The advantage of the invention is that, without it being necessary to use a tightening instrument (a key), it is possible to change, easily and very quickly, the mandrels for nut and screw rivets in the riveting tool. Work productivity is thereby substantially increased. Moreover, in order that harmful injuries should not occur during operation of the riveting tool, the passage opening in the nozzle is covered with a protective sliding covering sleeve.
[0005] A further advantage is the fact that, thanks to the ease with which the stem for nut or screw rivets can be attached to the fast clamping system, the invention makes it possible to eliminate problems with non-observance of manufacturing tolerance, especially of alignment of the rotatable parts of the riveting tool.
Brief description of the drawings
[0006] The invention can be described in more detail by means of the attached drawings. Figure 1 shows in section the front part of the riveting tool with the clamping device in the position where the passage opening in the nozzle is covered by the protective sliding covering sleeve. Figure 2 shows the clamping device with the sliding covering sleeve slipped to the outer end of the riveting tool, when the passage opening in the nozzle is uncovered and it is thus possible to easily grasp with the fingers the enclosing sleeve, push it back against the spring to the stop and unscrew the stem for nut or screw rivets. Figure 3 is a schematic representation of the body of the stem for screw rivets.
Description of the Preferred Embodiments
[0007] To the traction mandrel 13 of the riveting tool is attached a fast clamping system for blind nut and screw rivets which can have the following arrangement. To the threaded traction mandrel 13 there is screwed a lock-nut 9 with a recess and tightly fitted to the lock-nut there is a traction sleeve 11 which is inserted or loosely fitted in the enclosing sleeve 12. The traction sleeve 11 is now, in the position described, firmly connected to the traction mandrel 13 (alternatively, it can be an integral part of the traction mandrel 13) so as to continually turn with it. The traction sleeve 11 and the enclosing sleeve 12 are mutually secured against axial shifting and turning. The actual means of securing, not illustrated in the attached drawings, can be effected by a whole range of known methods. For example, there can be a recess in the enclosing sleeve 12 into which is inserted a safety ring, resting against the stepped end of the traction sleeve 11 (securing against mutual axial shifting). There can also be an axial groove in the enclosing sleeve 12, into which a safety pin goes, inserted into the traction sleeve 11 (security against mutual turning). In the space between the enclosing sleeve 12 and the peripheral recess in the traction sleeve 11 is a compression spring 10 which is fitted between the stepped end of the traction sleeve 11, to be more precise, between the safety ring tightly fitted to it, located in the recess in the enclosing sleeve 12, and the lock-nut 9. That whole assembly is screwed to the traction mandrel 13 and tightened up to the lock-nut 9. The outer positions of the enclosing sleeve 12 are defined by the recess in the lock-nut 9, the traction sleeve 11 and the enclosing sleeve 12 (the position of the safety ring).
[0008] The traction sleeve 11 is further provided with an inner thread, into which is screwed the stem 1, 4 (of the nut or screw rivets), whose collar has at least one flattened plane on its outer circumference corresponding to an inner peripheral surface of the adjacent part of the enclosing sleeve 12 (for example, if the enclosing sleeve 12 has its inner surface in the shape of a hexagon, the traction sleeve 11 has an outer surface with a corresponding hexagonal shape).
[0009] The fast clamping system is fitted, together with the traction mandrel 13, in the front nozzle 5 of the riveting tool which has a passage opening in the area of the enclosing sleeve 12. The passage opening in the nozzle 5 is covered by a sliding covering sleeve 7, made from plastic for example, between which and the nozzle 5 there is a protective flexible O-ring 8, situated on the side of the passage opening, in the direction of the outer end of the nozzle 5. The device is further provided with a stop 6 (for example, another O-ring) to prevent the covering sleeve 7 slipping from the nozzle 5. Into the front nozzle 5 which is fastened to the front part of the riveting tool, an extension 2 with a lock-nut 3 (screwed to the thread of the extension 2) can be screwed from the front, the extension having a central passage opening for the stems 1, 4, which can determine the length of the stem 1, 4 for nut or screw rivets, protruding from the tool.
[0010] The extension 2 is unscrewed while changing the stem 1, 4 to which the nut or screw rivet is screwed. The covering sleeve 7 slips in a forward direction from the riveting tool and, through the access opening in the nozzle 5, it is possible to grasp with the fingers the enclosing sleeve 12 and gradually draw it back against the pressure of the compression spring 10 in the direction of the rear part of the tool. In that position it is easy to unscrew the stem 1 or 4 by hand from the clamping system. A further stem 1 or 4 as required is then inserted and is loosely screwed by hand to the traction sleeve 11. The enclosing sleeve 12 is then released (the spring 10 pushes it back to its original position) and by unscrewing the stem 1 or 4 slightly from the traction sleeve 11, the outer peripheral surfaces of the collar of the stem 1 or 4 line up with the inner peripheral surface of the enclosing sleeve 12. The covering sleeve 7 is retracted again and an extension 2 is screwed to the appropriate corresponding stem 1, 4 (for each dimension of stem there is an appropriate corresponding dimension of extension).
1. A device for clamping a stem to the traction mandrel of a riveting tool, characterized by the fact that the traction mandrel (13) has a traction sleeve (11) loosely fitted in the enclosing
sleeve (12) and mutually secured with the enclosing sleeve against axial shifting
and turning; between the enclosing sleeve and the peripheral recess in the traction
sleeve (11) there is a compression spring (10); the traction sleeve (11) has an inner
thread into which is screwed the stem (1, 4), whose collar has at least one flattened
plane on its outer circumference corresponding to an inner peripheral surface of the
adjacent part of the enclosing sleeve (12), the device being fitted, together with
the traction mandrel (13), in the nozzle (5) of the riveting tool, the nozzle having
a passage opening in the area of the enclosing sleeve (12).
2. A device for clamping a stem to the traction mandrel of a riveting tool according
to claim 1, characterized by the fact that a compression spring (10) is fitted against a lock-nut (9) screwed to the traction
mandrel (13).
3. A device for clamping a stem to the traction mandrel of a riveting tool according
to claims 1 or 2, characterized by the fact that the securing of the traction sleeve (11) and the enclosing sleeve (12) against
mutual axial shifting is effected by means of a safety ring, fitted in a recess of
the enclosing sleeve (12) and resting against the stepped end of the traction sleeve
(11).
4. A device for clamping a stem to the traction mandrel of a riveting tool according
to any of the preceding claims 1 to 3, characterized by the fact that the passage opening in the nozzle (5) is covered by a sliding covering sleeve
(7), between which and the nozzle (5) there is a protective flexible O-ring (8), situated
on the side of the passage opening, in the direction of the outer end of the nozzle
(5), the device being provided with a stop (6) to prevent the covering sleeve (7)
slipping from the nozzle (5).
5. A device for clamping a stem to the traction mandrel of a riveting tool according
to any of the preceding claims 1 to 4, characterized by the fact that the traction sleeve (11) is an integral part of the traction mandrel (13).