DE2217108A1 - Device for driving a reciprocating gear member - Google Patents

Description

Applicant's file number: Docket EN 9-69-062

Device for driving a reciprocating gear member

The invention relates to a device for driving a gear member that can be moved back and forth between two positions, in particular a print hammer, by means of electromagnetic Powers.

It is known (US Pat. No. 3,241,480) to use a pressure hammer held in its rest position by spring force to move an electromagnet with the interposition of a longitudinally displaceable rod into its pressure position. Here the arrangement is made so that after the armature hits its core, the rod is under the influence of their kinetic energy continues to move and so, so to speak, in free flight the print hammer into its stop position pivoted further.

209844/0805

It is also known (U.S. Patent 3,507,213) a print hammer to accelerate directly through the magnetic core of an electromagnet, which is then under the influence of its kinetic energy moves further into the pressure position and receives a rebound energy in the same, which by renewed Exciting the electromagnet can be destroyed. In this device, too, the print hammer is held in place by a spring Held at rest.

It is the object of the invention to provide a device for driving a transmission member which can be moved back and forth between two positions to create that does not require a spring that holds the gear member in its rest position or safely returns it and by a more precise temporal return of the gear member to its rest position one compared to the known Devices higher drive frequency permitted.

The invention solves this problem by means of an electromagnetic magnet system, the core structure of which provides two different paths for the magnetic flux, each of which is assigned to a position of the gear element to be moved, designed as a magnet armature (38 or 40), with at least one control coil ( 20 or 28 or 22 or 30) is provided for switching the magnetic flux from one path to the other. The drive force of the device according to the invention is almost constant despite switching off the drive pulse long before the gear member arrives in its working position, since the magnetic resistance of the gap between the flat pole faces decreases during the breakdown of the current. In the working position, a slight rebound force is sufficient to achieve the return of the gear member, which is also effected under the influence of magnetic force. It can thus only by determining electrical quantities, in contrast -to springs are not subject to aging and do not have large tolerances for the return

Docket EN 9-69-062 »9844/080

Leadership required period of time can be precisely determined so that the drive frequency of the gear member to be moved is greater than that of devices that have springs and greater rebound forces require.

Further features of the invention can be found in the claims.

Details of the invention are described below using an exemplary embodiment illustrated in the figures. Show it:

Fig. 1 is a schematic of a print hammer drive device,

FIG. 2 is a side view of the print hammer drive device of FIG. 1;

3 shows a diagram to illustrate the driving force and the restoring force,

4 shows a diagram to illustrate flight times and compressive forces for different air gaps and

Fig. 5 is a diagram of the drive and damping pulse & ~ _o

The print hammer drive device IO has a magnetic core structure which has the central core part 14 arranged between the upper core part 11 and the lower core part 12. The core parts 11, 14 and 12 are connected to one another by means of the core parts 13, 15 connected to form a complete magnetic circuit. The upper and lower core parts 11 and 12, respectively each equipped with a protruding pole piece 16 or 18, on which a work coil 20 or 22 is arranged. Of the central core part 14 consists of laminations stacked on top of one another, the pole pieces 24 protruding upwards and downwards, 26, each of which has a control coil 28 or

Docket EN 9-69-062 209844 / 080S

records. Next to the upholstered counters 16, 24 and opposite one another Toothed, curved pole faces 32, 33 are arranged, each of which has teeth along its curve. Similarly, the pole pieces 18, 26 have similar curved pole faces 34, 36 formed by teeth.

The anchors 38, 40 are pivotable about the bolts 42 and 44, which are mounted in support arms 46 and 48, each of which fastened by means of rivets 50 and screws 52 to the plastic body 54 connecting the core parts 11 and 12 to one another is. The armatures 38, 40 have flat pole faces 58, 60 and 62, 63, respectively, which are arranged to run essentially radially are that they can be moved into a position in which they come to rest on the pole pieces 16, 24 or 18, 26, as soon as the armatures 38, 40 pivot about their bolts 42, 44 in the opposite direction to the clockwise direction of rotation or in the clockwise direction of rotation are. The armatures 38, 40 are equipped with toothed, curved parts 64, 66 and 68, 70, which are connected to the toothed, curved pole faces 32, 33 and 34, 36 of the core parts 11, 14, 12 cooperate. The anchors 38, 40 are each equipped with an arm 72 or 74, each of which has a hammer stop surface 76 or 78 for impact of the paper to be inscribed 80 and the ribbon 82 against a type element 84, which on one along the print line moving type chain can be attached. The anchor adhesive plate 86 made of non-magnetic material or plastic, made of polyurethane, for example, is attached to one or both surfaces of the pole pieces 16, 18, 24, 26 to provide a To prevent sticking of the armature to the pole pieces. Resilient stops are provided that are made out with rubber buffers 90, 91 provided leaf springs 88 and 89 exist. The leaf springs 88, 89 are in slots 92 and 93 of the Plastic body 54 attached and adjusting screws 94 resp. 95 determine the rest position of the armatures 38 and 40, respectively.

Docket EN 9-69-062 209844 / 08QS

The armature 38 is shown in its attracted position, in which the flat pole face 58 is essentially the armature adhesive plate 86 brings against the protruding pole piece 16 to abut. In this position, the hammer stop surface strikes 76 the paper to be inscribed 80 and the ribbon 82 against the type element 84. In this position, the toothed, Curved parts 64, 66 a position in which their teeth are essentially the gaps between the teeth Core parts 11, 14 provided toothed, curved pole faces 32, 33 are opposite. The overlap of the teeth of the toothed parts 64, 66 with respect to the teeth of the stationary, toothed, curved pole faces 32, 33 is 20 to 40% in order to obtain a sufficient return movement force. The armature 40 is shown in its rest position, in which its flat pole faces 62, 63 from the protruding pole pieces 18, 26 are furthest apart. In this position are the teeth of the toothed, curved Parts 68, 70 of armature 40 substantially opposite the teeth of the stationary, toothed, curved pole faces 34, 36.

In the position of the armature 40 shown, the work coil 17 located on the lower core part 12 generates a magnetic Έ1 \ χβφ2 which normally successively traverses the air gap between the toothed, curved pole faces 36, 34 and the toothed, curved parts 68, 70 of the armature 40 . When a pulse is applied to the control coils 22, 30, a substantial part of the magnetic flux φ2 is branched off from the aforementioned path and traverses the path between the projecting pole pieces 18, 26 and the flat pole faces 62, 63 as magnetic flux φΐ, whereby a driving force is exerted on the armature 40 in order to pivot the same in an anti-clockwise direction, whereby the air gaps between said pole pieces and pole faces are closed. When the anchor 40 in its

Docket EN 9-69-062 209844/0805

2217103

Working position is moved, strikes its hammer stop surface 78 the paper 80 to be inscribed and the flat pole faces 62, 63 come essentially by means of the armature, adhesive pads 86, as shown for armature 38, abut the protruding pole pieces 18, 26. In this The teeth of the spaced-apart toothed, curved parts 68, 70 of the armature 40 are in position their with the corresponding teeth of the toothed, curvilinear Pole faces 34, 36 are moved out of the aligned position and are in the position shown for armature 38 Gap position in which you have sufficient backward movement force can generate in order to be able to move the armature 40 back into its rest position as soon as the control coils 22, 3O supplied pulse has ended.

When, as shown in Figures 1 and 2, a plurality of print hammer drive devices 10 are arranged side by side surrounds the upper core parts 11 of all print hammer driving devices the common work coil 19 and the lower core parts 12 of all print hammer driving devices the common work coil 17 to create a constant magnetic field common to all print hammer drive devices forces to align for minimal magnetic reluctance, with separate control coils 20, 28 are provided on the protruding core parts 16, 24 of each print hammer driving device. In the resting position about 10% of the main flow generated by the work coil 19 traverses the air gap between the projecting ones Pole pieces 16, 24 and the flat pole faces 58, 60 of armature 38, which ensures a minimum of initial movement delay while at the same time one minimal interaction between neighboring paths occurs. The excitation of the control coils 20, 28 produces a sufficient one magnetomotive force to cause the magnetic flux to change its path and to produce a torque. this

Docket EN 9-69-062 209844/0805

results in a rotary movement of the armature 38, causing the teeth the curved pole faces 32, 33 and the curved parts 64, 66 of the armature 38 get into their saturation state and thereby most of the flux into the main air gap between the salient pole pieces 16, 24 and the deflect flat pole faces 58, 60.

Measurements showed the following conditions: The initial flow in the return path is approximately 2000 flow lines.

The initial flow in the drive path is approximately 300 lines.

Shortly before the start of the movement, the return movement field has 800 lines and the drive field 1650 lines.

After completion of the work movement, the return movement field has 350 lines and the drive field has 2300 lines. These Results were at approximately 880 amperes of the work coils 17, 19 and at 1800 ampere windings for the control coils 20, 28, 22 and 30 are achieved.

As can be seen from Figure 3, takes in the movement of the ^; 'jikers to the driving force, namely following the path A and the backward movement force falls following the path B. The drive current can be switched off long before the end of the work movement, because while the current breaks down, the resistance of the drive gap between 16 - 58 decreases, whereby the drive force is kept positive and almost constant. Once the stop occurs, a very small recoil force is required to create a return force that follows path C. The relationship between the input pulse size and the required energy is shown in FIG. This also shows the changes in the time of flight as a function of the drive impulse and the length

Docket EN 9-69-062

209844/0805

7217108

the movement.

In one embodiment, the toothed curved parts 64, 65 and 68, 70 of the armature have 38 and 40, respectively a radius of about 17.4 mm and the tooth width is about 1.2 mm, while the slots are about 1.7 mm wide are. The thickness of the armature is approximately 2.3 mm, so that the print hammer drive devices or the print hammers one May have a pitch of 2.54 mm. The gap between the anchor and the core parts is 0.05 mm and the anchor adhesive plate has a thickness of 0.35 mm. Two anchors above and two anchors below form an opposing arrangement a compact print hammer unit with the upper and lower core parts spaced 2.4 mm apart to form a total thickness of 7.2 mm with the central core portion 19 mm thick and each leg a width of approximately 12.7 mm. The print hammer drive device has a compressive force of approximately 75 to 230,000 ergs, generated with a response time of 0.6 to 1.1 milliseconds, a movement time of 1.9 to 3 milliseconds and a usable stroke from 0.9 to 1.3 mm. As shown in Fig. 5, the drive and damping pulses a and b can be from each other be spaced to give the displacement curve c.

Docket EN 9-69-062 209844/0805

Claims (6)

- Q _ PATENT CLAIMS Device for driving a between two positions reciprocating gear member, in particular a pressure hammer _{f by} means of electromagnetic forces, characterized by an electromagnetic magnet system, the core structure of which provides two different paths for the magnetic flux, one of which each has a position of the armature 38 or 40 is assigned to the gear member to be moved, at least one control coil (20 or 28 or 22 or 30) being provided for switching the magnetic flux from one path to the other. 2. Apparatus according to claim 1, characterized in that the pivotably mounted magnet armature (38 or 40) seen in one sense of rotation in alternating Sequence: a flat, roughly radial pole face (58, 60 or 62, 63) and a curved, toothed part (64, 66 or 68, 70) and the magnetic core correspondingly formed pole pieces (16, 24 or 18, 26) and curved, toothed pole faces (32, 33 or 34, 36) and the Tooth arrangement is made so that this curved parts (64, 66 and 68, 70) penetrate magnetic flux generates a torque opposite to that generated by the other flux is directed. 3. Apparatus according to claim 2, characterized in that the magnetic core is essentially U-shaped is that one leg (11 or 12) of the U-shape is surrounded by a coil (19 or 17), and that each the parallel legs (11, 14 or 92, 14) of the U-shape 209844/0805 each with a protruding pole piece (16, 24 or 18, 26) the flat pole face and one pole piece each with the curved, toothed pole face (32, 33 or 34, 36) and that the projecting pole pieces (16, 24 or 18, 26) each receive a control coil (20, 28 or 22, 30). 4. Apparatus according to claim 2, characterized in that the magnet armature (38 or 40) in its rest position, in which the teeth of its toothed, curved parts (64, 66 or 68, 70) those of the toothed, curved pole faces (32, 33 or 34, 36) of the magnet core opposite, rests against an elastic stop (88, 90 or 89, 91). 5. Apparatus according to claim 4, characterized in that the elastic stop is a cantilevered, adjustable Represents leaf spring (88 or 89) with a rubber buffer (90 or 91) at its free end. 6. The device according to claim 2, characterized in that the magnet armature (38 or 40) has an arm (72 or 74), the free end of which is designed as a hammer stop surface (76 or 78). 209844/0805 A4 Blank page