JPH0410065Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a hammer stamping device in which a hammer for striking a type carrier such as a type wheel is provided protruding from an electromagnetic plunger.

"Prior art and its problems" In this type of hammer stamping device, the hammer moves forward by energizing the electromagnet and energizing the plunger, and by demagnetizing the electromagnet, the plunger and the hammer release the return spring. However, if the plunger and hammer move forward due to reaction after retracting, the hammer may strike the type carrier twice, resulting in poor print quality, or the hammer may get stuck between the type carriers, causing damage to the type carrier. It is necessary to prevent the recoil of the plunger and hammer since it has harmful effects such as inhibiting rotation and emitting noise.

Conventional methods for preventing this have included interposing a spring between the main body of the electromagnet and the rear cover, or interposing a spring between the rear cover and the plunger to buffer the recoil of the plunger. It was a pain to assemble things.

In addition, in a case where a recess is formed on the inner surface of the rear cover, a washer that contacts the plunger is freely accommodated in the recess, and the washer is used as a buffer, and the washer is moved each time the plunger moves back and forth. As it collides with the inner surface of the recess in the rear cover, the inner surface is worn away by the angular edge of the washer, and the stopping positions of the plunger and hammer gradually move back, causing the striking position of the hammer and the selection point of the type carrier to become misaligned, resulting in printing. Errors occurred, and print quality deteriorated.

The present invention aims to eliminate the above-mentioned drawbacks of a washer that is movably housed in the recess of the rear cover, and also to improve the cushioning effect by improving the movability of the washer.

"Means for solving the problem" A circular plate-shaped packing made of synthetic resin is fitted into the circular recess of the rear cover of the electromagnet, and a disk smaller than the inner diameter of the plate-shaped packing is inserted into the plate-shaped packing. A shaped washer is freely movable therein. The peripheral edge of this washer and the inner peripheral corner of the dish-shaped packing shall be arcuate surfaces. A ventilation hole is continuously provided in the center of the rear lid and the center of the dish-shaped packing, and a ventilation hole having an inner diameter larger than these holes is provided in the center of the washer.

``Function'' In addition to the washer, the plunger is also cushioned by a dish-shaped packing made of synthetic resin. The inner surface of the recessed portion of the rear lid is protected by this packing, and since the peripheral edge of the washer and the inner peripheral corner of the dish-shaped packing are arcuate surfaces, the dish-shaped packing is less likely to wear out.

In addition, a ventilation hole is provided in the center of the back cover of the electromagnet and the dish-shaped packing, and a ventilation hole is also provided in the center of the washer, which creates a negative pressure inside the dish-shaped packing and restricts the movement of the washer. Moreover, since the vent hole in the washer has a larger inner diameter than the vent holes in the rear cover of the electromagnet and the dish-shaped packing, the ventilation action is performed no matter where the washer moves within the dish-shaped packing. .

"Embodiment" Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In this hammer stamping device, a coil 4 and a core 5 wound around a bobbin 3 are fixed in a cylindrical metal main body case 1 so as to constitute an electromagnet 2 in the main body case 1. A plunger 7 is slidably fitted into a hard synthetic resin guide tube 6 on the front side of the core 5. This plunger 7 is
A flat hammer 8 is integrally provided on the front side. The plunger 7 is biased rearward by a return coil spring 9 that passes through the hammer 8. The front end of the hammer 8 is connected to a front cover 10 made of hard synthetic resin that is fitted into the front end opening of the main body case 1.
It protrudes slidably through a cross-shaped guide hole 11.

On the other hand, the rear end opening of the main body case 1 is closed by a disc-shaped rear lid 12 made of metal (for example, aluminum). The rear cover 12 is attached to the core 5 by a set screw 13. This rear lid 12 has a wire lead-out recess 14 formed at the lower side of its periphery, a circular recess 15 formed at the center of the inner surface, and a ventilation hole 16 bored at the center of this recess 15. There is. Inside this recess 15, there is a plate-shaped hard synthetic resin (for example, acetal resin) that matches the inner surface shape of the recess 15.
A made gasket 17 is removably fitted. A metal disc-shaped washer 18 smaller than the inner diameter of the dish-shaped packing 17 is freely movably accommodated therein. A ventilation hole 19 that is continuous with the ventilation hole 16 of the rear cover 12 is provided in the center of the dish-shaped gasket 17, and a ventilation hole 19 that is continuous with the ventilation hole 16 of the rear lid 12 is provided in the center of the washer 18.
A ventilation hole 20 having an inner diameter larger than that of holes 6 and 19 is provided. The inner circumferential edge corner 17a of the dish-shaped packing 17 and the circumferential edges 18a on both front and rear sides of the washer 18 are both arcuate surfaces.

In such a structure, when the coil 4 is energized, the plunger 7 is advanced against the coil spring 9, and the hammer 8 projects forward and strikes a type carrier (not shown). When the coil 4 is demagnetized, the plunger 7 moves backward together with the hammer 8, and the rear end surface 7a of the plunger 7 collides with a freely movable washer 18, and this washer 18 collides with a dish-shaped packing 17 made of hard synthetic resin. The washer 18 and the dish-shaped packing 17 prevent the plunger 7 from rebounding when it is returned to its backward position. Since the inner surface of the recess 15 of the rear lid 12 is protected by the dish-shaped packing 17, it is prevented from being abraded by the washer 18. Further, the peripheral edge 18a of the washer 18 is an arcuate surface, and the inner peripheral corner 17 of the dish-shaped packing 17
Since a is also an arcuate surface, the washer 18 has little abrasion effect on the dish-shaped packing 17. Even if it wears out, you only need to replace the dish-shaped gasket 17.
There is no need to replace the rear cover 12.

Furthermore, the electromagnet rear cover 12 and dish-shaped gasket 17
Since ventilation holes 16 and 19 are provided in the center of the washer 18, and a ventilation hole 20 is also provided in the center of the washer 18, negative pressure is created in the dish-shaped packing 17, and movement of the washer 18 is restricted. Never. Moreover, since the ventilation hole 20 of the washer 18 has a larger inner diameter than the ventilation holes 16 and 19 of the rear cover 12 and the dish-shaped packing 17, the ventilation effect is achieved by moving the washer 18 to any position within the dish-shaped packing 17. It is also done.

"Effects of the invention" The hammer stamping device of the invention has the following effects.

Since the recoil of the plunger and hammer is buffered by a plate-shaped synthetic resin packing in addition to the washer, the recoil prevention effect is good.

Since the inner surface of the recessed portion of the rear lid is protected by the dish-shaped packing fitted thereto, the rear lid can be prevented from being worn out by the washer.

Since the peripheral edge of the washer and the corner of the inner circumferential edge of the dish-shaped packing are made into arcuate surfaces, there is little wear of the dish-shaped packing by the washer, and even if it wears out, only the dish-shaped packing needs to be replaced, and there is no need to replace the rear cover. ,
Economical.

A ventilation hole is provided in the rear cover of the electromagnet and the center of the dish-shaped packing, and a ventilation hole is also provided in the center of the washer, so that the movement of the washer will not be restricted due to negative pressure inside the dish-shaped packing. Moreover, since the vent hole in the washer has a larger inner diameter than the vent holes in the rear cover of the electromagnet and the dish-shaped packing, the ventilation effect is performed no matter which position the washer moves within the dish-shaped packing. Therefore, it is possible to improve the free movement of the washer and improve the buffering effect.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is an exploded perspective view. 2...Electromagnet, 7...Plunger, 8...Hammer, 12...Rear cover, 15...Recess, 16,1
9,20...Vent hole, 17...Dish-shaped packing, 1
7a... Inner peripheral edge corner of dish-shaped packing, 18... Washer, 18a... Peripheral edge of washer.

Claims (1)

[Scope of utility model registration request] A hammer for striking the type carrier was protruded from the plunger of the electromagnet, a circular recess was formed on the inner surface of the rear cover of the electromagnet, and a washer that came into contact with the rear end of the plunger was freely accommodated in the recess. In the hammer stamping device, a circular dish-shaped packing made of synthetic resin is fitted into the circular recess, and a disc-shaped washer smaller than the inner diameter of the dish-shaped packing is freely movably accommodated in the dish-shaped packing. And the peripheral part of this washer,
The inner peripheral corner of the dish-shaped packing is made into an arcuate surface, and a ventilation hole is continuously provided in the center of the rear lid and the center of the dish-shaped packing, and the center of the washer has an inner diameter larger than that of these ventilation holes. A hammer stamping device characterized by having a ventilation hole.