CZ9901854A3 - Device for controlling movement of riveting tool pulling member - Google Patents

Abstract

In the invented device for controlling movement of riveting tool pulling member said pulling member (1), being terminated by a screw mandrel, is brought into motion by a pressure medium using a rotary pneumatic motor (7) and pressure medium distribution system that is performed in a valve head (9) and enabling change in rotational direction of the motor (7). At the same time, said pulling member (1) is mounted slidably relative to the pressure medium distribution system, with restriction of stroke in axial direction within the body (2) of the riveting tool operating hydraulic piston wherein said operating hydraulic piston body (2) with said rotary pneumatic motor (7) and said valve head (9) connected thereto are arranged one after other and have a through hole in a common axis. At least one bypass chamber (30) with an inlet (10) of pressure medium, and valves (19, 20) are arranged in the valve head (9) to control distribution of the pressure medium, whereby the valves (19, 20) are adapted to alternate transfer pressure medium to one of two inlets of the rotary pneumatic motor (7) in dependence on the action of force produced either from the side of the pulling member (1) or from the side opposite to the pulling member (1).

Description

Technical field

The invention relates to a device for controlling the movement of a pulling member for nut or screw rivets of a riveting tool.

BACKGROUND OF THE INVENTION

The rotary movement of the pulling bolt for nut or bolt rivets is carried out in riveting tools by a pneumatic motor whose function is controlled by a double-sided spring-loaded spool with seals. In some riveting tool designs, the slide is firmly connected to a control rod whose axis coincides with the slide axis by means of which the slide position is adjusted. The slider is guided in a through-hole of the valve head of the tool, provided with a plurality of manifolds connected to the pneumatic motor to rotate it in both directions and to the surrounding environment and transmits a translational movement from the pull bolt. At present, the valve head designs of the riveting tools are provided with a relatively complex system of manifolds, which is expensive to manufacture and increases in cost. Also, the slide is usually made up of several parts, which in the functional positions must be displaced axially relative to each other. This increases the demands on manufacturing precision and hence the production cost of the riveting tool. Also disadvantageous is the relatively large clearance (1 to 1.5 mm) in the rest position of the tool between the outer shoulder of the pull bolt and the inner shoulder of the hydraulic piston body against which the pull bolt is mounted. When starting work with the tool, that is, during riveting, it is necessary to first limit this play (the hydraulic piston moves the pulling screw only after the play has been overcome). The greater this clearance, the greater the pressure air losses.

Current embodiments of said riveting tools are described in a number of patents, e.g., German Patent Nos. 3308915, 3306827, 3216696, British Patent 1327407, and US Patent Nos. 3929056 and 3744291.

SUMMARY OF THE INVENTION

Disadvantages of the present state are largely eliminated by the new design of the device for controlling the movement of the pulling member of the riveting tool according to the invention. The pulling member for nut or screw rivets is terminated by a threaded mandrel and is moved by the pressure medium by means of a rotary pneumatic motor and

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A pressure medium manifold formed in the valve head to change the direction of rotation of the engine. At the same time, the pulling member is displaceably disposed in the axial direction of the stroke in the working hydraulic piston body of the riveting tool, the hydraulic piston body with the rotary pneumatic motor and the associated valve head being arranged one after the other. SUMMARY OF THE INVENTION In order to control the distribution of the pressurized medium, a pressure chamber with a pressurized medium supply is provided in the valve head and valves are adapted to alternately transfer the pressurized medium to one of the two inlets of the rotary pneumatic motor. either on the side of the pulling member or on the side opposite the pulling member.

An essential advantage of the present invention is a significant reduction to almost clearance clearance (approximately 0.2 mm) between the shoulder of the pulling member transmitting the pulling force during riveting and the internal shoulder of the working hydraulic piston body. This significantly reduces the loss of compressed air during riveting. In current designs of slider tools, this clearance must be so large (about 1.5 mm) to allow movement of the control slider, its rod and pull bolt when the slider is pushed towards the rivet, i.e. the pneumatic motor rotates to the left. For example, with small rivet diameters M4, the rivet needs to be deformed over a path of about 2 mm, in which case the loss of compressed air required to deform the rivet is almost 50%.

The pressure-fluid transfer chamber is provided with a valve at each of its two opposite ends lying in the axis of the device, wherein the valves are adapted to alternately transfer the pressure-medium to one of the two inlets to the rotary pneumatic motor the device either on the side of the pulling member or on the side opposite to the pulling member. The arrangement of the transfer chamber with both valves in the axis of the device is simpler in construction and manufacture.

Each valve consists of a seat, a seal and a sliding element with a closing element, wherein the sliding element in the open position of the valve tightly closes a through hole from one outside of the valve head, the valve head having a throughflow channel downstream of the seat. connected to the inlet to the · 000 ·· 0 ··· 00 · 0 • 00 · · 0 0 rotary pneumatic motor. In this tool arrangement, the control path for bringing the tool into any of the functional states is shortened.

The transfer chamber is preferably arranged as an extended shoulder of the through hole, the opposing ends of which are formed as valve seats, wherein each seat bears a ball forming a closing element, and the supply of pressure medium is connected to the transfer chamber between the two balls. The control force required to rotate the pneumatic motor to one side or the other is less than that of the present embodiments. At the same time, the reliability of returning the valves to the rest position is increased compared to using only springs.

The pulling member may be provided with an extended shoulder for which a recess with axial clearance is formed in the working hydraulic piston body, the stop surface for limiting the travel of the pulling member being arranged on the side of the threaded mandrel.

The pulling member is terminated on the inside by an external hexagon, which engages a rotary pneumatic motor through transmission, where a connecting rod is freely guided in the through hole between the hexagon and the sliding element of the first valve arranged on the facing side of the transfer chamber. The sliding element of each of the two valves is a cylindrical body with a graduated diameter, the narrower part of which passes through the through-hole in the valve head and abuts the valve closing ball in the transfer chamber, with a groove O-ring against the through hole is provided with a saddle bevel. The control path for bringing the tool into any of the functional states is reduced.

The outer end of the valve head is closed by a lid on whose inner shoulder a wider portion of the cylindrical body of the sliding member of the second valve facing the lid is supported, and a thrust member of the second valve is received in the lid through hole adjacent to the device through hole. The pressure element is formed by a spring which abuts one end on the sliding element of the other valve and the other end against the body of the riveting tool. After riveting the joint and releasing the tool release, the spring pressure causes the pneumatic motor to automatically spin in such a direction that the threaded darkness is unscrewed from the rivet joint.

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Overview of the drawings

For further explanation, an exemplary embodiment of the invention is illustrated in the accompanying drawings, which is described in more detail in the following description. 1 is a cross-sectional view of an air distribution device of a rotary pneumatic motor for controlling the rotational movement of the pulling member of the riveting tool in the rest position of the tool. Fig. 2 shows the arrangement of Fig. 1 after pushing the pulling member inwardly of the riveting tool, for example after applying the nut rivet to the threaded mandrel of the pulling member and pushing inward. In this operating position, the pneumatic motor rotates in one direction. Figures 2a, 2b and 2c show in detail in this functional position a cross-sectional and front view of the valve head with the valves and the visible position of the individual seals, as well as an example of the arrangement of the individual air distribution channels. Figures 3, 3a, 3b and 3c show a valve head with valves, seals and air distribution channels in another functional position, after applying force to the valves in the opposite direction, i.e. towards the rivet.

DETAILED DESCRIPTION OF THE INVENTION

1 shows a part of a riveting tool consisting of a working hydraulic piston 2 assembly with a through hole in which a pulling member 1 is slidably and rotatably mounted. The pulling member 1 is provided with an external widened shoulder 26 which, in riveting tool operating position (riveting) 1) rests on the inner recess 27 in the working hydraulic piston body 2. At its outer end, the pulling member 1 is threaded to screw a mandrel onto which a nut or screw rivet is fastened. Seals for hydraulic oil and compressed air are mounted on the working hydraulic piston body 2. In this case, the working hydraulic piston body 2 is shaped with a plurality of recesses which correspond to the outer shape of the planetary gearbox and the rotary pneumatic motor 7 with the blades 15. At the opposite end of the working hydraulic piston body 2 is an internal thread for screwing the valve head 9 that the contact surfaces of the pneumatic motor 7, its front face 17 and rear face 8 are tightly pushed together to prevent loss of compressed air from the pneumatic motor 7 during operation. Position of the pneumatic motor body 7, its rear face 8 and valve head 9 it is fixed with respect to one another by a locking pin 6 which extends through parallel axial holes in said components. In order to simplify production or assembly, one or two sealed inserts may be housed in the valve head 9.

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At the inner end, the pulling member 7 is provided with an external hexagon 34 which is engaged by the rotary pneumatic motor 7 via a gear (hexagon 34 engages from a corresponding hole in the planet gear carrier 4). It is thus freely movable in the axial direction and at the same time transmits the rotational movement from the pneumatic motor 7.

The entire planetary gear assembly (bearing 3, carrier 4, internal toothing 5 with gears 18) and pneumatic motor 7 has a central through hole for the control rod 33 of the first valve 19, which is further connected in this direction from the pulling member 1 to the tool end chamber 30 and second valve 20. All these components are coaxially aligned with the pull member 2 and the working hydraulic piston body 2. In other words, all the aforementioned parts of the device are arranged in succession with a continuous through hole in a common axis.

In the valve head 9 a pressure medium (compressed air) manifold is provided which allows the direction of rotation of the pneumatic motor 7 to be changed. In order to control the compressed air distribution, a transfer chamber 30 is provided in the valve head 9 with an inlet 10 of pressurized medium (air). and two valves 19,20. These valves 19 and 19, respectively. 20, which are located at each of the two opposite ends of the transfer chamber 30 lying in the axis of the device, are adapted to alternately transfer compressed air to one of the two inlets to the rotary pneumatic motor 7 depending on the force of the member 2 or on the side opposite to the pull member 7. Each valve 19, 20 comprises a seat, a gasket 32, 32 'and a slide 21, 21' with a shut-off element 22, 22 '. The sliding element 21, 21 'in the open position of the valve 19, 20 tightly closes the through hole from one outside of the valve head 9, the valve head 9 being provided with a bypass channel (first and second crank channel 23) , 24), connected to the inlet of the rotary pneumatic motor 7.

The transfer chamber 30 is arranged as an extended shoulder of the described through-opening of the device, the opposing ends of which are formed as valve seats 19, 20. A plastic ball constituting the closure member 22, 22 ' The pressure medium (air) supply 10 is connected to the transfer chamber 30 between the two balls. The sliding element 21, 21 'of each of the two valves 19, 20 is a cylindrical body with a graduated diameter, the narrower part of which passes through the through-pass. · »» »» »» »» »· · · · · · · · · · · · · · · · · An aperture in the valve head 9 and abutting the valve closing ball in the transfer chamber 30, wherein at the transition to the wider part, an O-ring (forming a 32,32 'seal) is grooved against which the through hole is provided with a saddle bevel.

The outer end of the valve head 9 is closed by a cover 11 on the inner shoulder of which a wider portion of the cylindrical body of the slider 21 ^{1 of the} second valve 20 facing the cover 11 is supported. position. A push-through element of the second valve 20 is formed in the through-hole of the lid 11 following the through-hole of the device, formed by a spring 13 which bears one end against the slide 21 'of the other valve 20 and the other end against the body 31 of the riveting tool. , a nut for automatic rivet dial adjustment, etc.).

As already mentioned, the valve head 9 is provided with a plurality of ducts 10, 23, 24, 25 connected to the pneumatic motor 7 to rotate it in one direction, to rotate it in the opposite direction and to connect it to the environment. Opposite to the transfer chamber 30 is provided in the valve head 9 a pressure medium (air) inlet 10 formed by an inlet radial passage (may also be oblique), to which two cranked channels 23, 24 are provided, which are individually connected on one side into the pneumatic motor 7 and on the other hand into the inner space 28 facing the pneumatic motor 7 or the outer outer space 29. The valve head 9 is further provided with a through axial channel 25 (not necessarily axial; another arrangement) connecting the exhaust of the pneumatic motor 7 to the environment.

In the rest position of the riveting tool (FIG. 1), compressed air is supplied through an inlet radial passage (pressure medium inlet W) to a transfer chamber 30, which is located between the first and second valves 19, 20 in the extended through hole of the valve head 9 the ends are formed as valve seats 19, 20. The transfer chamber 30 is sealed because a plastic ball forming a closing element 22, 22 ' In this position, the pneumatic motor 7 does not rotate.

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Pushing the threaded mandrel of the pulling member 1 towards the inside of the tool (eg by means of a nut or screw rivet held by the operator in the hand) moves the first valve 19 relative to the valve head 9 (see Figs. 2, 2a, 2b and 2c). The ball forming the closure member 22 of the first valve 19 ceases to seal, while the respective O-ring (seal 32 of the first valve 19) abuts the sealing seat (saddle bevel of the through-hole in the valve head 9) and seals. In this position of the riveting tool, the compressed air is supplied through the inlet 10 to the transfer chamber 30, from there to the transfer chamber with the narrowed portion of the slider 21 'of the first valve 19 and further through the crank channel 23 (see FIG. is rotated in one direction (for example to the right to screw the nut rivet onto the threaded mandrel of the pull member). The compressed air passes through the rotating pneumatic motor 7 and exits therefrom both through the exhaust duct (through axial duct 25 communicating with the environment through the outer space 29 and through-holes in the lid 11) and through the second crank duct 24 (see Figs. 2b, 2c). opening into the transfer space at the tapered portion of the slider 2Γ of the second valve 20, from where it is directed to the outer space 29 and further out of the tool (O-ring, seal 32 'of the second valve 20, leaks). Upon discontinuation of the pressure on the pulling member 1 inwardly of the tool, the compressed air returns the ball of the first valve 19 back to the seat and thus the whole assembly to its original position. The pneumatic motor 7 stops. The pressure on the pulling member 1 is usually discontinued when the rivet face, when screwed onto the threaded mandrel, rests on an extension (not shown) through which the threaded mandrel of the pulling member 7 passes through its inner opening. Thus, when the rivet pulling member 2 is rotated, it is displaced forwards, thereby breaking said pressure on the pulling member 1.

The screwed rivet is inserted into the prepared hole and by pressing the trigger of the riveting tool, the hydraulic piston with the pneumatic motor 7 and valve head 9 is moved away from the rivet into the tool. By this displacement the rivet is deformed and the joint is riveted. Simultaneously with this movement, the clearance between the sliding element 21 * of the second valve 20 and the adjacent compression spring 13 (approximately 0.4 mm) is first defined. Further, the second valve 20 and its ball (closure member 22 ') are moved towards the threaded mandrel until the O-ring of the second valve 20 (seal 32') is seated on its seat (saddle bevel of the through-hole in the valve head) 9). With the further movement of the hydraulic · · · «α α α α α α α α α α α α α α α α α α α The compression spring 13 is compressed inwardly of the piston towards the inside of the tool. After riveting the joint and releasing the tool trigger, the spring pressure (not shown) automatically returns the hydraulic piston assembly with the pneumatic motor 7 and valve head 9 towards the rivet. Since the second valve 20 is in the open state due to the pressure of the spring 13, the pneumatic motor 7 automatically rotates in the opposite direction (eg, to the left) and thereby the threaded mandrel is unscrewed from the rivet joint (from the internal hole of the rivet thread). The pneumatic motor 7 rotates as long as the pressure of the spring 13 keeps the second valve 20 in the open position. The spring 13 ceases to press immediately before the second valve 20 returns to its initial position, which corresponds to the aforementioned clearance of about 0.4 mm. Due to the compressed air supplied to the transfer chamber 30, the second valve 20 is closed and the pneumatic motor 7 is stopped. The tool is now ready for the next operation.

By applying a force to the second valve 20 (by spring 13 or hand) in the inward direction of the tool, i.e. towards the rivet, the compressed air flows through the valve head 9 and the pneumatic motor 7. Once the O-ring of the second valve 20 (seal 32 ') abuts its seat (saddle bevel of the through-hole in the valve head 9), the compressed air from the transfer chamber 30 (see Figs. 3a, 3b, 3c) enters the transfer space at the narrowed portion of the slider 21 'of the second valve 20 and a cranked channel 24 (see FIG. 3a) into the interior of the pneumatic motor 7, which rotates in the opposite direction (eg, to the left). Compressed air is exhausted from the rotating motor from the pneumatic motor 7 through an exhaust port (a through axial passage 25 communicating with the environment through the outer space 29 and through the openings in the lid 11) and a first crank passage 23 opening into the overflow space at the narrowed portion the valve 21 of the first valve 19, from where it is directed to the interior space 28 communicating with the through axial channel 25 and further out of the tool (the O-ring seal 32 on the slider 21 of the first valve 19 leaks).

Industrial applicability

The device according to the invention is intended for riveting tools in which the rotary movement of the pulling screw for nut or screw rivets is performed by a pneumatic motor.

Claims (9)

PATENT REQUIREMENTS ························· I A device for controlling the movement of a pulling member of a riveting tool, wherein the pulling member (1) terminated by a threaded mandrel is actuated by a pressure medium by means of a rotary pneumatic motor (7) and a pressure medium manifold formed in the valve head (9) in the sense of rotation of the motor (7), and wherein the pulling member (1) is simultaneously displaceable, with axial stroke limitation, mounted therein in the working hydraulic piston body (2) of the riveting tool, The motor (7) and the connected valve head (9) are arranged one after the other with a through bore in a common axis, characterized in that at least one transfer chamber (30) with an inlet is arranged in the valve head (9) for controlling the pressure medium distribution. (10) pressure media and valves (19, 20), wherein the valves (19, 20) are adapted to alternate p relieving the pressure medium to one of the two inlets to the rotary pneumatic motor (7) depending on the force applied by either the pulling member (1) or the side opposite the pulling member (1). Device according to claim 1, characterized in that the transfer chamber (30) with the pressure medium supply (10) is provided with a valve (19 and 20) at each of its two opposite ends lying along the axis of the device, 19, 20) are adapted to alternately release the pressure medium to one of the two inlets to the rotary pneumatic motor (7) depending on the force applied in the direction of the device axis either from the pulling member (1) or from the side opposite the pulling member (1). ). Device according to claim 1 or 2, characterized in that each valve (19,20) consists of a seat, a seal (32,32 ') and a slide (21,2T) with a closing element (22,22'), wherein the sliding element (21, 2T) in the open position of the valve (19, 20) tightly closes a through hole from one outside of the valve head (9), the valve head (9) being provided with a bypass behind the seat a duct connected to the inlet of the rotary pneumatic motor (7). -n / 7W-w 4. Device according to one of Claims 1 to 3, characterized in that the overflow chamber (30) is arranged as an extended shoulder of the through hole, the opposing ends of which are formed as valve seats (19, 20), each ball seating a closing ball. element (22, 22 '), and the pressure medium supply (10) is connected to the transfer chamber (30) between the two balls. Device according to one of Claims 1 to 4, characterized in that the pulling member (1) is provided with an extended shoulder (26) for which an axial clearance recess (27) is provided in the working hydraulic piston body (2), the stop surface for limiting the stroke of the pulling member (1) is arranged on the side of the threaded mandrel. Device according to one of Claims 1 to 5, characterized in that the pulling member (1) is terminated on the inside by an external hexagon (34) which meshes with the rotary pneumatic motor (7) through the transmission, where between the hexagon (34) and a sliding member (21) of the first valve (19) disposed on the upstream side of the transfer chamber (30) is a loosely guided connecting rod (33) in the through hole. Device according to one of Claims 3 to 6, characterized in that the sliding element (21, 21 ') of each of the two valves (19, 20) is formed by a cylindrical body with a graduated diameter, the narrower part of which passes through a through hole in the valve head. (9) and abutting the valve closing ball in the transfer chamber (30), wherein at the transition to the wider part, a groove O-ring is mounted in the recess, against which the through hole is provided with a saddle bevel. Device according to one of Claims 1 to 7, characterized in that the outer end of the valve head (9) is closed by a cover (11) on whose inner shoulder a wider part of the cylindrical body of the sliding element (21 ') of the second valve (20) is supported. ) facing the lid (11), wherein a push member of the second valve (20) is received in the through hole of the lid (11) following the through hole of the device. Apparatus according to claim 8, characterized in that the pushing element is formed by a spring (13) which bears on one end on the sliding element (21 ') of the other valve (20) and on the other end on the body (31) of the riveting tool.